Comprehensive Energy Master Plan Report

Transcription

1 Comprehensive Energy Master Plan Report Prepared for Purdue University West Lafayette, Indiana October 2011 FINAL DRAFT

2 Comprehensive Energy Master Plan Report Prepared for Purdue University West Lafayette, Indiana October 2011 Prepared by Burns & McDonnell Engineering Company, Inc. Kansas City, Missouri FINAL DRAFT COPYRIGHT 2011 BURNS & McDONNELL ENGINEERING COMPANY, INC.

3 INDEX AND CERTIFICATION Comprehensive Energy Master Plan Report Report Index Chapter Number Number Chapter Title of Pages 1 Executive Summary 12 2 Introduction 5 3 Demand Side Management 46 4 Control System Review 15 5 Renewable and Alternative Energy Options * 10 6 Production Modeling 43 7 Building Interconnection Model 4 8 Distribution Modeling 68 9 Dispatch Management Tool Review 4 10 Base Purchase Calculator Review 3 11 Review of Design Standards 1 12 Economic Analysis Conclusions and Recommendations 8 14 Implementation Plan 7 * Chapter provided by Purdue University Certification I hereby certify, as a Professional Engineer in the state of Indiana, that the information in the document was assembled under my direct personal charge, with the exception of Chapter 5 Renewable and Alternative Energy Options. This report is not intended or represented to be suitable for reuse by Purdue University or others without specific verification or adaptation by the Engineer. This certification is made in accordance with the provisions of the laws and rules of the Indiana State Board of Registration for Professional Engineers under the Indiana Administrative Code. Blake E. Ellis, PE Indiana No. PE Date: (Reproductions are not valid unless signed, dated, and embossed with Engineer s seal)

4 Comprehensive Energy Master Plan FINAL DRAFT Table of Contents TABLE OF CONTENTS Page No. 1.0 EXECUTIVE SUMMARY Purpose Observations and Analysis Energy Use (Demand Side Management) Energy Distribution Energy Production Control Systems RecommendationS Energy Use (Demand Side Management) Energy Distribution Energy Production Control Systems Implementation Summary INTRODUCTION CEMP Mission Statement Goal Project Purpose Living Document Acknowledgements Demand Side Management Approach Demand Side Management Survey Evaluation of Energy Conservation Measures (ECMs) Extrapolation of the Results to Campus Development of an Implementation Plan Distribution Approach Steam Chilled Water Production Approach DEMAND SIDE MANAGEMENT Building Selection Investigation Procedure General Building Observations Specific Building Observations Young (Ernest C.) Hall Hovde (Frederick L.) Hall of Administration Mechanical Engineering Krannert Building Purdue University TOC-1 Burns & McDonnell

5 Comprehensive Energy Master Plan FINAL DRAFT Table of Contents Electrical Engineering Hansen (Arthur G.) Life Sciences Research Building Lynn (Charles J.) Hall (1993 and 2005 sections) McCutcheon Residence Hall Summary of Results Extrapolation to the Campus ECM Energy Savings Calculations ECM Descriptions Recommended and Evaluated ECM-01: Convert Multi-Zone AHU to VAV ECM-02: Convert Dual-Duct AHU to VAV ECM-03: Air-Side Economizer - AHU Modification ECM-04: Air-Side Economizer - BAS Sequencing ECM-05: Air-Side Heat Recovery on Exhaust Air ECM-06: Eliminate Simultaneous Heating and Cooling ECM-07: Reduce ACH Rates in Unoccupied Lab Spaces ECM-08: Convert 100% Fresh Air AHU to Mixed Air ECM-09: New Space Temperature Sensors w/scheduling and Occupancy ECM-10: Low Flow Water Fixtures ECM-11: Water-Side Economizer - Plate HX at Plant ECM-12: Insulate Steam Condensate Piping ECM-13: Replace IGVs with Fan VFDs ECM-14: Disable Steam Humidifiers in Off-Season ECM-15: Change Air Filters ECM-16: Static Pressure Reset on VAV AHUs and Exhaust Systems ECM-17: Optimize DAT Temp/RH from Make-Up Air AHUs ECM-18: Schedule Equipment Off (Computers) ECM Descriptions Recommended, not Evaluated ECM-19: Repair/Replace Leaking CHW Valves ECM-20: Replace Modified Three-Way CHW Valves with Two-Way ECM-21: Repair Duct Leakage ECM-22: Replace Faulty Temperature Sensor ECM-23: Optimize Heat Recovery Water Loop Operation ECM-24: Elevator Motor Replacement ECM-25: CHW Btu-Meter Commissioning ECM-26: Isolate Steam Systems in Off-Season ECM-27: Eliminate Vacuum and Compressed Air Leaks ECM-28: Residence Hall FCU Control with Smart-Phone Operation ECM-29: Eliminate CHWR Temperature Control Trend Data Analysis Implementation Plan CONTROL SYSTEM REVIEW Current Building Automation Systems Configuration User Interface Design Reviews and Sequence Standards on New Projects Trouble Call Procedure Purdue University TOC-2 Burns & McDonnell

6 Comprehensive Energy Master Plan FINAL DRAFT Table of Contents 4.5 Improving Troubleshooting Effort Preventative Maintenance Improved Preventative Maintenance Procedures Control System Graphics and Information Upgrade Expanding Sequence of Operation Standards Sharing of Information Continuous Commissioning Effort Energy/Utility Monitoring RENEWABLE AND ALTERNATIVE ENERGY OPTIONS Introduction Alternative Fuel Co-Firing Organic Waste Biomass Energy Crops Material Waste Biomass Purdue and Alternative Fuels Factors considered when evaluating an alternative fuel: Typical evaluation process: Fuels considered as alternative fuels for Wade s boilers in the past: Solar Thermal Photovoltaic Cells Wind Geothermal Heat Pump Energy Storage Implementation issues Purdue and Wind Energy Purdue and Solar Energy Purdue and Anaerobic Digestion Energy Production Purdue and Geothermal Heat Pumps Renewable and Alternative Energy Options Summary PRODUCTION MODELING Approach Demand Profiles Production Capacity Production Options Overview of CHP and TES Analysis and Results Utilization of Steam Driven Assets Chilled Water Production Curtailment BUILDING INTERCONNECTION MODEL Approach Determining the Load Purdue University TOC-3 Burns & McDonnell

7 Comprehensive Energy Master Plan FINAL DRAFT Table of Contents Capital Costs Annually Recurring Costs Life Cycle Cost Analysis Results DISTRIBUTION MODELING Steam Load Definition Approach Results Distribution Improvement Scenarios Conclusions Chilled Water Load Definition Approach Results Distribution Improvement Scenarios Conclusions Demand Side Management Effect Building Investigation Conclusions DISPATCH MANAGEMENT TOOL REVIEW BASE PURCHASE CALCULATOR REVIEW REVIEW OF DESIGN STANDARDS General Requirements Chilled Water System Components HVAC Systems HVAC Steam and Condensate Piping ECONOMIC ANALYSIS Chilled Water Assets Steam Production Electric Production Installation Program Options Analyzed Assumptions Base Case Option 1 Implementation of Thermal Energy Storage (TES) Option 2 Implementation of TES and Combined Heat & Power CHP Option 3 Implementation of Demand Side Management (DSM) Projects Option 4 Implementation of DSM Projects and TES Purdue University TOC-4 Burns & McDonnell

8 Comprehensive Energy Master Plan FINAL DRAFT Table of Contents Option 5 Implementation of DSM Projects, TES, and CHP Economic Analysis Results CONCLUSIONS AND RECOMMENDATIONS Demand Side Management Control Systems Distribution Systems Steam Chilled Water Production Steam Production Chilled Water Production IMPLEMENTATION PLAN Demand Side Implementation Control System Technology Improvement Control System Coverage Organizational Issues Implementation Steps Distribution Systems Implementation Production Systems Implementation Program Management CEMP Road Map * * * * * Purdue University TOC-5 Burns & McDonnell

9 Comprehensive Energy Master Plan FINAL DRAFT List of Tables LIST OF TABLES Table No. Page No. Table 1-1: Campus Wide Energy Saving Potential Table 1-2: Steam Improvement Option Summary Table 3-1: Selected Buildings for Demand Side Evaluation Table 3-2: Young Hall Recommended ECMs Table 3-3: Hovde Hall Recommended ECMs Table 3-4: Mechanical Engineering Recommended ECMs Table 3-5: Krannert Building Recommended ECMs Table 3-6: Electrical Engineering Recommended ECMs Table 3-7: Hansen Life Science Building Recommended ECMs Table 3-8: Lynn Hall Recommended ECMs Table 3-9: McCutcheon Residence Hall Recommended ECMs Table 3-10: Summary of Building Survey Results Table 3-11: Buildings Included in Campus Level Demand Side Management Table 3-12: Buildings Included in Campus Level Demand Side Management (cont) Table 3-13: Building Classifications as a Percentage of Campus Table 3-14: Energy Savings by Building Type Table 3-15: Energy Savings Extrapolated to Campus Table 4-1: Chilled Water Return Reset Schedule Table 6-1: Existing Chilled Water Production Assets Table 6-2: Existing Steam Production Assets Table 6-3: Existing Dispatched Electricity Production Assets Table 6-4: Taurus 65 Combustion Turbine Generator Performance Summary Table 6-5: Taurus 70 Combustion Turbine Generator Performance Summary Table 6-6: Titan 130 Combustion Turbine Generator Performance Summary Table 6-7: Gas Fired Boiler Performance Summary Table 6-8: Pumps Table 6-9: Boiler Fans Table 6-10: Chillers Purdue University TOC-6 Burns & McDonnell

10 Comprehensive Energy Master Plan FINAL DRAFT List of Tables Table 6-11: Existing Chillers Table 6-12: Wade Utility Plant Cooling Tower Loads Table 6-13: Cooling Tower Design Capacity Table 6-14: Curtailment Electricity Costs Table 7-1: Building Connection Evaluation Example Table 8-1: Current Peak Wade Utility Plant Summary Table 8-2: 5 Year Peak Wade Utility Plant Summary Table 8-3: 20 Year Peak Wade Utility Plant Summary Table 8-4: 5 Year Building Addition Summary Table 8-5: Calibration Results Table 8-6: Improvement Option Summary Table 8-7: Branch Line Summary Table 8-8: Base Case Chilled Water Summary Table 8-9: 5-Year Scenario Chilled Water Summary Table 8-10: 20-Year Scenario Chilled Water Summary Table 8-11: 5-Year Building Addition Summary Table 8-12: Chilled Water System Improvement Option Summary Table 8-13: Chilled Water Branch Line Summary Table 10-1: Daily Timeframes Table 12-1: Chilled Water Asset Retirement Schedule Table 12-2: Steam Production Asset Retirement Schedule Table 12-3: Matrix of Options Analyzed Table 12-4: Commodity Escalation Rates Table 12-5: Commodity Escalation Rates Table 12-6: Base Case Steam Asset Roadmap Table 12-7: Base Case Chilled Water Roadmap Table 12-8: Option 1 Steam Asset Roadmap Table 12-9: Option 1 Chilled Water Roadmap Table 12-10: Option 2 Steam Asset Roadmap Table 12-11: Option 2 Chilled Water Roadmap Table 12-12: Option 3 Steam Asset Roadmap Purdue University TOC-7 Burns & McDonnell

11 Comprehensive Energy Master Plan FINAL DRAFT List of Tables Table 12-13: Option 3 Chilled Water Roadmap Table 12-14: Option 4 Steam Asset Roadmap Table 12-15: Option 4 Chilled Water Roadmap Table 12-16: Option 5 Steam Asset Roadmap Table 12-17: Option 5 Chilled Water Roadmap Table 12-18: Economic Analysis Summary Table 12-19: 2014 Cost Summary Table 12-20: Life Cycle Cost Summary ($2012) Table 13-1: Campus Wide Energy Saving Potential Table 13-2: Steam Improvement Option Summary * * * * * Purdue University TOC-8 Burns & McDonnell

12 Comprehensive Energy Master Plan FINAL DRAFT List of Figures LIST OF FIGURES Figure No. Page No. Figure 1-1: Existing Controls System Responsibilities Figure 1-2: Proposed Control System Responsibilities Figure 1-3: Life Cycle Cost Summary ($2012) Figure 3-1: Btu/hr Saved per Installed Cost by Building Type Figure 3-2: Peak Energy Savings by Building Type Figure 3-3: [ECM-06] Eliminate Simultaneous Heating and Cooling Figure 3-4: [ECM-29] Eliminate CHWR Temperature Control Figure 3-5: [ECM-09] New Space Temperature Sensors w/scheduling and Occupancy 3-45 Figure 4-1: Example of Ladder-Logic Programming Figure 4-2: Example of a Thermo-Graphic Floor Plan Control Interface Figure 4-3: Example of an Air Handling Unit Control Interface Figure 4-4: Control System Programming Code Figure 4-5: Existing Controls System Responsibilities Figure 4-6: Proposed Control System Responsibilities Figure 4-7: Building Energy Assessment Tool (1 of 3) Figure 4-8: Building Energy Assessment Tool (2 of 3) Figure 4-9: Building Energy Assessment Tool (3 of 3) Figure 6-1: Chilled Water Load Growth Figure 6-2: Steam Load Growth Figure 6-3: Electric Load Growth Figure 6-4: CHP versus Separate Heat and Power Production Figure 6-5: Example TES Dispatch Strategy Figure 6-6: Wade Utility Plant Flow Diagram 125 psig-to-15 psig Drives Figure 6-7: 125 psig-to-15 psig Steam Drives Break-Even Point Figure 6-8: Wade Utility Plant Flow Diagram 650 psig-to-125 psig Drives Figure 6-9: TG1 Heat Rate Figure 6-10: TG1 Minimum LP Section Flow Figure 6-11: Wade Utility Plant Flow Diagram Steam Driven Chillers Purdue University TOC-9 Burns & McDonnell

13 Comprehensive Energy Master Plan FINAL DRAFT List of Figures Figure 6-12: Wade Chiller 6 Break-Even Ratio Figure 6-13: 125 psig Steam Chillers - Break Even Ratio Figure 6-14: Cooling Water Pump Curve Figure 6-15: Cooling Tower Capacity Figure 8-1: Base Case High-Pressure System Pressures Figure 8-2: Base Case Low-Pressure System Pressures Figure 8-3: Base Case Velocity Figure 8-4: 5 Year Scenario High-Pressure System Pressures Figure 8-5: 5 Year Scenario Low-Pressure System Pressures Figure 8-6: 5 Year Scenario Velocity Figure 8-7: 20 Year Scenario High-Pressure System Pressures Figure 8-8: 20 Year Scenario Low Pressure System Pressures Figure 8-9: 20 Year Scenario Velocity Figure 8-10: Third Street to PA Pit High-Pressure System Pressures Figure 8-11: Third Street to PA Pit Low-Pressure System Pressures Figure 8-12: Third Street to PA Pit Velocity Figure 8-13: Jischke Pipe Upsize High-Pressure System Pressures Figure 8-14: Jischke Pipe Upsize Low-Pressure System Pressures Figure 8-15: Jischke Pipe Upsize Velocity Figure 8-16: NE Upsize High-Pressure System Pressures Figure 8-17: NE Upsize Low-Pressure System Pressures Figure 8-18: NE Upsize Velocity Figure 8-19: Biochemistry Building Calibration Chart Figure 8-20: Heine Pharmacy Calibration Chart Figure 8-21: Burton Morgan Center Calibration Chart Figure 8-22: Base Case System Pressures, NE Quadrant Figure 8-23: Base Case System Pressures, NW Quadrant Figure 8-24: Base Case System Pressures, SW Quadrant Figure 8-25: Base Case System Pressures, SE Quadrant Figure 8-26: Base Case System Velocities Figure 8-27: 5-Year Scenario Pressures, NE Quadrant Purdue University TOC-10 Burns & McDonnell

14 Comprehensive Energy Master Plan FINAL DRAFT List of Figures Figure 8-28: 5-Year Scenario Pressures, NW Quadrant Figure 8-29: 5-Year Scenario Pressures, SW Quadrant Figure 8-30: 5-Year Scenario Pressures, SE Quadrant Figure 8-31: 5-Year Scenario Velocities Figure 8-32: 20-Year Scenario Pressures, NE Quadrant Figure 8-33: 20-Year Scenario Pressures, NW Quadrant Figure 8-34: 20-Year Scenario Pressures, SW Quadrant Figure 8-35: 20-Year Scenario Pressures, SE Quadrant Figure 8-36: 20-Year Scenario Velocities Figure 8-37: NW Plant Pump Upgrade Pressures, NE Quadrant Figure 8-38: NW Plant Pump Upgrade Pressures, NW Quadrant Figure 8-39: NW Plant Pump Upgrade Pressures, SW Quadrant Figure 8-40: NW Plant Pump Upgrade Pressures, SE Quadrant Figure 8-41: NW Plant Pump Upgrade Velocities Figure 8-42: New 18" Pipeline Pressures, NE Quadrant Figure 8-43: New 18" Pipeline Pressures, NW Quadrant Figure 8-44: New 18" Pipeline Pressures, SW Quadrant Figure 8-45: New 18" Pipeline Pressures, SE Quadrant Figure 8-46: New 18" Pipeline Velocities Figure 8-47: New North Sat. Plant Pressures, NE Quadrant Figure 8-48: New North Sat. Plant Pressures, NW Quadrant Figure 8-49: New North Sat. Plant Pressures, SW Quadrant Figure 8-50: New North Sat. Plant Pressures, SE Quadrants Figure 8-51: New North Sat. Plant Velocities Figure 9-1: Purdue Dispatch Management Tool Screenshot Figure 9-2: TG1 Heat Rate as a Function of LP Section Flow Figure 9-3: TG1 Output Figure 10-1: Base Purchase Spreadsheet Figure 10-2: Average Hourly RTP Price and Electric Load - FY Figure 12-1: Base Case Steam Asset Roadmap Figure 12-2: Base Case Chilled Water Roadmap Purdue University TOC-11 Burns & McDonnell

15 Comprehensive Energy Master Plan FINAL DRAFT List of Figures Figure 12-3: Option 1 Steam Asset Roadmap Figure 12-4: Option 1 Chilled Water Roadmap Figure 12-5: Option 2 Steam Asset Roadmap Figure 12-6: Option 2 Chilled Water Roadmap Figure 12-7: Option 3 Steam Asset Roadmap Figure 12-8: Option 3 Chilled Water Roadmap Figure 12-9: Option 4 Steam Asset Roadmap Figure 12-10: Option 4 Chilled Water Roadmap Figure 12-11: Option 5 Steam Asset Roadmap Figure 12-12: Option 5 Chilled Water Roadmap Figure 12-13: Total Life Cycle Cost ($2012) Figure 12-14: Total Life Cycle Cost Savings ($2012) Figure 12-15: 2014 Cost Summary Figure 12-16: Life Cycle Cost Summary ($2012) Figure 13-1: Existing Controls System Responsibilities Figure 13-2: Proposed Control System Responsibilities Figure 14-1: CEMP Road Map Schedule of Projects Figure 14-2: CEMP Road Map - Cash Flow Diagram * * * * * Purdue University TOC-12 Burns & McDonnell

16 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary 1.0 EXECUTIVE SUMMARY Purdue University owns and manages the heating, cooling and electrical energy production and distribution for the majority of the West Lafayette campus. Within the next year, the last location to add heating production at the Wade Utility Plant will be filled with a new boiler and the last location for adding cooling production to the Satellite Chiller Plant will be filled with a new chiller. The traditional response to this situation would be to analyze the increasing energy needs of the campus and add new plants as necessary to meet the energy demand. Purdue staff has also been focused on reducing the energy usage of the buildings and have already accomplished the quickly implemented, highest return on investment energy savings initiatives. In addition, Purdue s internal investigations indicated that potential energy savings still existed on campus. The energy use at the buildings is interrelated with the capital and operating costs to produce and distribute that energy to the buildings, In order to better understand the interrelated costs on a Life Cycle Cost basis, Purdue commissioned this Comprehensive Energy Master Plan (CEMP). 1.1 PURPOSE The purpose of the CEMP is to investigate the energy production, distribution and building demand on the West Lafayette Campus. The investigation analyzed the chilled water, steam and electrical production at the utility plants, modeled the chilled water and steam distribution systems and estimated the energy savings potential in the campus buildings. The result of this analysis is a fiscally and environmentally responsible Comprehensive Energy Master Plan that provides Purdue guidance in managing the energy production and consumption on the campus as it continues to grow and evolve. 1.2 OBSERVATIONS AND ANALYSIS Energy Use (Demand Side Management) Prior to commencing with the CEMP, Purdue staff had implemented a number of energy savings measures to reduce the energy consumption across campus. This included high payback items like lighting retrofits and instituting fume hood sash control procedures. Purdue staff also believed that additional energy savings was available in the buildings. A sample of eight buildings was selected jointly with Purdue for energy audits. The audits were performed during the summer and calculated the energy savings potential for those eight buildings. The results from the eight buildings were then extrapolated to Purdue University 1-1 Burns & McDonnell

17 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary the campus to provide an estimate of the potential impact of the energy savings reductions. A summary of the energy saving potential is listed in Table 1-1 below: Table 1-1: Campus Wide Energy Saving Potential Annual Energy Savings Electricity 10,500 MW-hr Heating 250,000 MMBtu Cooling 7,500,000 Ton-hrs Annual Demand (Peak) Savings Electricity 0.8 MW Heating 80 MMBtu/hr Cooling 2,800 Tons For Purdue to achieve these savings, several energy conservation measures (ECM s) would require implementation across the campus. The installation cost for these measures has an order of magnitude cost of $32 million with an associated energy savings of $2.6 million per year. Implementation of the ECM s would affect the majority of the major buildings on campus and would require several years to implement. For this analysis, it was assumed that the implementation of the ECM s would be performed over a six year period. Observations developed as part of the survey in conjunction with interview of building operators, occupants and the University s facility operations team includes the following items: Based on the conditions observed, it appears that the maintenance of the buildings has not been supported with adequate resources to maintain condition and efficient operation. Zone maintenance personnel could benefit from additional training and access to the building automation system to correct building operational issues. Maintenance personnel are reliant on the Building Systems Group for system troubleshooting. New Lab/Research spaces on campus maintain a minimum occupied air exchange rate of six Air Changes per Hours (ACH). Opportunities exist in selected existing labs to reduce the air change rate during occupied and unoccupied times while offering significant reductions in energy. Our understanding is that Purdue is currently working to reduce air change rates in labs during unoccupied times. Purdue University 1-2 Burns & McDonnell

18 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Space temperature set back is currently not utilized in a majority of campus locations. Rooms that have varying occupancy patterns based on academic calendar and scheduled events have a high opportunity for energy savings. Most of the campus facilities that were investigated currently utilize high flow water devices (urinals, faucets, toilets, etc). There are numerous opportunities to save water by retrofitting these fixtures with low flow devices Energy Distribution Steam and chilled water distribution systems were analyzed as part of the CEMP. A model was created for the distribution systems and Purdue provided peak building load information. These models were then calibrated to actual operating information. Once the models were calibrated, they were used to analyze the distribution systems at current conditions, 5 years in the future and 20 years in the future. The last step in the process was to create improvement options and test them in the model to represent the system performance under the conditions expected in the 5 year model Steam Steam is currently produced only at the Wade Utility Plant, which results in the process delivering steam to the north end of the campus without excessive pressure drop becomes a big challenge. One particular location labeled the PA Pit (located north of Tower Drive near Cary and Ford) provides the best indicator of overall distribution system operation at distributing steam to the north end of campus. Due to planned building growth, in the 5 year plan the steam pressure at the PA Pit falls below the level desired for satisfactory system operation. Three options were analyzed to improve the pressure at the PA Pit. This first option establishes a new steam distribution path from the south to the north end of campus. The other two options focus on upgrading the existing north-south distribution infrastructure. A summary of the results of these options are indicated in Table 1-2: Table 1-2: Steam Improvement Option Summary PA Pit Pressure PA Pit Scenario Construction Cost $ (psig) (psi) 5 Year Option 1 - Third Street to PA Pit $1,700, Option 2 - Jischke Drive Upsize $1,500, Option 3 - NE Pipe Upsize $1,900, Purdue University 1-3 Burns & McDonnell

19 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Chilled Water Chilled water is currently produced at the Wade Utility Plant on the south side of campus and the Satellite Chilled Water Plant on the northwest side of campus. Modeling of the chilled water distribution system indicates that supplying water from the satellite plant to the east and from the Wade Plant to the northeast portion of campus are the major stress points. Like the steam system, the chilled water system also needs improvements to meet the distribution requirements during the next 5 years. The chilled water system differential pressure in the northeast portion of campus was utilized as the reference point when analyzing improvement options. Options considered focused on alleviating restrictions for flow distributed from the west side of the campus near the existing chilled water plant to the northeast corner of campus. Locating additional chilled water plant capacity in the northeast corner of campus was one of the options considered Energy Production Analysis of the energy production focused on the production of steam, chilled water and electricity to meet the current and future campus energy requirements. Several options to meet the campus energy requirements were developed for both chilled water and steam. These options were then analyzed with an economic model with the final result being in the form of a road map for Purdue to follow to meet the production requirements Steam Boiler 1 at the Wade Utility Plant is a coal stoker boiler that was originally installed in 1961 and is scheduled to be retired during The loss of steam production from Boiler 1, coupled with anticipated demand growth results in a capacity deficiency that must be addressed to meet campus demand with an N+1 level of redundancy. Consequently Purdue is faced with a near term decision concerning what type of steam production asset should be installed. The CEMP analyzed a new gas boiler as well as three different size combined heat and power (CHP) options. Steam demand forecasts and associated capacity plans were developed through Chilled Water Similar to the analysis of the steam system, chilled water demand was forecast through 2038 and several options were created to meet the demand. This analysis indicated that Purdue does not have adequate chilled water production capacity to meet current needs. The chilled water options were created to provide an N+2 level of redundancy. As a result of the deficiency in current chilled water production Purdue University 1-4 Burns & McDonnell

20 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary capacity all options require a large investment in chilled water production as soon as practical so that Purdue can catch up with the production needs of the campus Control Systems Purdue utilizes control systems from two control companies (Automatic Logic and Siemens) and has two different user interfaces. Both control systems utilize a complex user interface that requires a high degree of understanding of the control system. In addition, all of the control information is located with the Building Systems Group and very little information is accessible to the IAQ technicians that are maintaining the buildings. This results in the Building Systems Group staff becoming involved with every trouble call throughout the campus. A more user friendly interface to the control systems would allow the IAQ technicians to access the information they need without involving the Building Systems Group and it would free up the Building Systems Group to focus on more campus wide initiatives. Section 4.0 has sample control systems graphics that have been utilized at other locations. Both control companies on the Purdue campus offer modern graphical user interfaces that provide a more user friendly experience. In addition, the access to the control system can be at the building level; however IAQ technicians would need additional training on how to take full advantage of the control systems capabilities. Cross-training of staff and introduction of new staff to the operations and programming efforts performed by the Building Systems Group is critical. The University s entire controls programming and operations knowledge base rests with just a few senior staff members (Console Group) who have responsibilities as shown on Figure 1-1: Existing Controls System Responsibilities. Purdue University 1-5 Burns & McDonnell

21 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Figure 1-1: Existing Controls System Responsibilities 1.3 RECOMMENDATIONS Energy Use (Demand Side Management) Implementation of a demand side management program to reduce the energy use in the buildings has a significant net present value (NPV) savings for Purdue. The amount of savings depends on the chilled water and steam production options chosen, however the lowest benefit still provides over $14.1 million of NPV savings to Purdue. We recommend that Purdue University implement a campus wide demand side management program to reduce the energy used in the buildings Energy Distribution The West Lafayette campus continues to grow and the energy distribution systems will require improvement to be able to deliver the required steam and chilled water to the campus buildings Steam We recommend the completion of the upsizing of the steam piping on Jischke Drive as the most cost effective, lowest risk option to meet the five year steam distribution demands. After the completion of the Jischke Drive improvements, we recommend further investigation towards installing a new north/south steam main from Third Street to the PA pit. The future load growth of campus buildings in The Island should be analyzed and then factored into the size of this piping and whether it should be direct buried or if a new utility tunnel should be installed. Purdue University 1-6 Burns & McDonnell

22 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Chilled Water We recommend the completion of the new 18 east/west main along Third Street as the most cost effective solution with the best pressure increase to meet the five year distribution requirements. Analyses of the chilled water production options below all indicate that new chilled water production is required. Depending on the option that Purdue implements, this could be a new satellite plant or the combination of a new satellite plant and a new chilled water storage tank. The location of these new production assets will have a great impact on the performance of the chilled water distribution system. We recommend that when these projects are implemented, the ability to get chilled water from the plant to the northeast portion of campus be included in the analysis Energy Production Steam Purdue is at a decision point regarding the technology to be implemented to replace the capacity of Boiler 1. A traditional gas boiler or a combined heat and power (CHP) system are the most viable options to add this capacity. The economic analysis indicates that both solutions have merit. Purdue will face another decision point when Boiler 2 is retired in the next decade. Installing a gas boiler now and deferring the decision to install CHP to when Boiler 2 is replaced is the lowest first cost option. The CHP system has a higher first cost, but provides an annual savings to the University. In the years until Boiler 2 is replaced, the savings is small and it becomes more significant after Boiler 2 is replaced. CHP has several additional benefits compared to the gas boiler in the areas of efficiency, reliability and the environmental impact. CHP provides efficiency benefits with lower operating costs, reduced emissions of all pollutants, increased power quality and reduced grid congestion and avoided distribution losses. Reliability benefits include the ability to produce power in the event of a grid outage. Finally the environmental benefits are centered on the dual use of energy (recycling of waste heat), utilizing less energy and lower emissions to the atmosphere per unit of useful energy. Finally, the economic analysis was performed over a 25 year horizon that is consistent with other analysis performed by Purdue, however the service life of both the boiler and CHP exceed that timeframe. If the timeframe of the analysis was extended to match the service life of the assets the economics would swing more in the favor Purdue University 1-7 Burns & McDonnell

23 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary of CHP. Therefore, we recommend the installation of CHP to replace Boiler 1 at the Wade Utility Plant. Note: If Purdue chooses to install a gas boiler to replace Boiler 1instead of CHP, we strongly recommend a thorough analysis of CHP when Purdue faces the decision to replace Boiler Chilled Water As stated above, Purdue does not currently have adequate chilled water production capacity for the current demand and the campus demand for chilled water continues to grow. Due to current demand, predicted load growth, and the pending retirement of several aging assets, Purdue needs to invest in increasing the capacity to provide chilled water to campus. The currently installed chiller capacity at Purdue in combination with the lower cooling demand in the night would support the addition of a thermal energy storage (TES) tank to utilize excess night time capacity and shift that cooling capability to the daytime when it is needed to meet the campus chilled water demand. This analysis utilized a 5 million gallon chilled water storage tank that can provide the equivalent of 8,000 tons of chiller capacity. The height of the TES tank is estimated to be between feet tall with a diameter of feet in diameter. The TES tank performance was then included in several chilled water options and analyzed in the economic model. The TES tank has a lower first cost than adding chillers and significant NPV savings over adding chillers. However the addition of a TES tank alone does not meet the chilled water demand and additional chillers are required. An analysis was also performed to determine if the additional chillers should be steam driven or electric driven assets. That analysis indicated that the operating cost of both types of chillers was nearly the same. However the first cost of the steam driven chiller is significantly higher. Therefore, we recommend installing a TES tank and constructing another satellite chilled water plant with at least one electric driven chiller. When chilled water demand increases, additional chillers will be required to be installed in the new satellite plant. The ideal location of the satellite plant is in the northeast portion of campus; however that is also the most difficult location for a plant. The TES tank and the new satellite chiller plant should be located together to take advantage of operating and maintenance efficiencies. The impact of these production assets on the distribution system must be evaluated and modifications required for effective distribution of the chilled water must be included in the planning. Purdue University 1-8 Burns & McDonnell

24 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Control Systems Building controls systems are the best tool for Purdue to utilize to reduce building energy use. However, the user interface for the controls systems must be upgraded to make the control system information accessible to the staff at the building level. We recommend the implementation of the control system graphical interfaces. After the control system interface is improved, integration of team activities with structured communication and training has the potential to significantly improve their performance. Figure 1-2: Proposed Control System Responsibilities provides diagram of the interrelated responsibilities. Figure 1-2: Proposed Control System Responsibilities An order of magnitude cost to implement was obtained from controls vendors for the control system improvements identified in the surveyed buildings. The pricing received had noticeable variability; however it did provide a range of $1 million to $2 million in a onetime cost. We recommend implementation of a program to review the HVAC system control sequences and revise them as necessary to provide appropriate occupancy conditions in the buildings. Because some of the current control system sequences were implemented to compensate for other system deficiencies, this implementation must include the correction of existing system deficiencies. This would include repair or replacement of items such as chilled water control valves, damper operators, steam traps, dampers, system Purdue University 1-9 Burns & McDonnell

25 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary components required for satisfactory operation. After the control sequences are implemented and the malfunctioning system components have been repaired or replaced the system should be commissioned to assure the proper operation. 1.4 IMPLEMENTATION Implementation of the recommendations above includes a wide variety of projects that are all interrelated. These projects range from energy efficiency improvements in as many as 90 campus buildings to chilled water and steam production and distribution projects. If Purdue proceeds with all of the recommended changes, over $80 million of construction will need to occur by To provide a consistent approach for the implementation of multiple projects in a relatively short time, we recommend utilizing a Program Management concept. A Program Management approach provides the practices and tools required to effectively coordinate the multitude of consultant and contractor agreements and activities required deliver the individual projects in alignment with the Purdue infrastructure goals. The exact structure of the Program Management Team (PMT) will need to be created with input from the selected Program Manager; however we envision a PMT that includes both Purdue staff and staff from the program management firm. The PMT will act on behalf of Purdue in the implementation of the CEMP and will ensure that any modification made in one particular project is executed with the understanding of the impact to the entire overall program. The most difficult task in selecting a Program Manager for this particular Program will be finding the individual that can understand and manage the entire program. This program has a project mix that ranges from industrial projects in the energy plants to light commercial projects to implement the energy conservation measures in the buildings. 1.5 SUMMARY The West Lafayette Campus of Purdue University continues to expand and with that expansion is an increase in the energy use of the buildings on campus. This CEMP has analyzed several options for Purdue to meet that increased demand and has determined that a multi-faceted approach has lowest net present value as indicated in Figure 1-3 and provides the overall best option for Purdue University. Purdue University 1-10 Burns & McDonnell

26 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Figure 1-3: Life Cycle Cost Summary ($2012) (Millions) $800 $700 $600 $500 $400 $300 $200 New Debt Service GT LTSA O&M RTP Demand RTP Energy HRSG Duct Burners GT Fuel Natural Gas Boilers Stoker Coal $100 $0 Base Option 1 Option 2 Option 3 Option 4 Option 5 CFB Coal & Limestone Base Purchase Demand Base Purchase Riders Base Purchase Energy DSM = Demand-Side Management TES = Thermal Energy Storage GT = Gas Turbine HRSG = Heat Recovery Steam Generator CFB = Circulating Fluidized Bed RTP = Real Time Power purchases LTSA = Long Term Service Agreement for Gas Turbine NPV = Net Present Value O&M = Operations and maintenance costs excluding fuel, electricity, and LTSA. Production Retire Boiler 1 at the Wade Utility Plant Add a 6.5 MW Combined Heat and Power (CHP) system at the Wade Utility Plant Add a 5 million gallon thermal energy storage (TES) system Add a new satellite chilled water plant with a minimum of one electric driven chiller Purdue University 1-11 Burns & McDonnell

27 Comprehensive Energy Master Plan FINAL DRAFT 1.0 Executive Summary Distribution Increase the size of the steam main along Jischke Drive Investigate the addition of a new north/south steam main from Third Street to the PA Pit Complete the installation of a new east/west chilled water main along Third Street Locate the future satellite chilled water plant as close to the northeast corner of campus as possible. Demand Side Management Implement a demand side management program to reduce the energy utilized in campus building. Controls System Simplify the user interface for the controls system and provide this information to the IAQ Techs. Integrate the roles of the Building Systems Group and the IAQ Technicians. Implement a program to review the HVAC system control sequences and revise them as necessary to provide appropriate occupancy conditions in the buildings. * * * * * Purdue University 1-12 Burns & McDonnell

28 Comprehensive Energy Master Plan FINAL DRAFT 2.0 Introduction 2.0 INTRODUCTION Purdue University has determined that energy management across the entire campus is a vital component of the University s environmental, fiscal, operational, and engagement goals. In support of this process, Burns & McDonnell has been engaged by Purdue to develop a Comprehensive Energy Master Plan (CEMP) that will provide a strategic framework for campus-wide energy management. 2.1 CEMP MISSION STATEMENT Enhance Purdue s ability to create a sustainable environment by improving the University s energy management, utility infrastructure and building operations in order to increase energy conservation, reliability and efficiency while managing Purdue s future capital investments Goal To reduce energy consumption and procurement costs, improve the reliability of University utility infrastructure systems, thereby reducing deferred maintenance, improving the campus environment and creating additional savings for future energy management initiatives while serving the steam, cooling, electric, water and sewage needs of campus Project Purpose To develop a fiscally and environmentally responsible Comprehensive Energy Master Plan (CEMP) that includes production, distribution and demand for potable water, chilled water, steam and electricity use at the buildings on the Purdue University West Lafayette Campus. CEMP will align with the vision and mission of the New Synergies and Sustainability strategic plans and will incorporate input from Purdue stakeholders. This integrated planning process will result in a formulation of a strategic framework for making fiscally sound and sustainable choices regarding energy production, distribution and demand Living Document The goal of the CEMP would be to provide Purdue with a greater understanding of current operations and a solid plan for short term development that is aligned with future long term campus energy requirements. Development of the future long term energy requirement is based upon projections of a number of factors that can be expected to change in the future. In addition, Purdue intends to implement recommendations contained in the CEMP that will improve current operating performance. These changing factors indicate that the CEMP will warrant revisiting as time progresses, requiring periodic updating to keep it current. Purdue University 2-1 Burns & McDonnell

29 Comprehensive Energy Master Plan FINAL DRAFT 2.0 Introduction We suggest updating the report after major projects are completed or when the assumptions have changed. Typically a master plan would be updated every five to seven years. 2.2 ACKNOWLEDGEMENTS Burns & McDonnell appreciates the opportunity to work with Purdue University in developing an energy master plan that investigates all facets of a campus energy use including the building energy requirements, distribution of energy to the buildings and production of energy in the plants. We want to extend our thanks and appreciation to the staff from Purdue University that provided assistance to us in many areas including gathering plant documentation, coordinating building investigations, providing insight on the system options and many other areas. We would like to specifically thank Bob Olson, Dan Schuster and Sally McGill for their assistance in this process. We would also like to commend Purdue for taking a holistic approach at managing the energy use on campus by including the three main components of energy use (production, distribution and building energy use) in one comprehensive report. The intent of the CEMP is to understand the interrelation of these components. We would also like to indicate that Purdue hasn t been standing still with regard to managing their energy. Several energy conservation measures that we would have expected to recommend have already been implemented by the University. Purdue also had a good understanding of the constraints of their distribution system and they have a diverse mix of production assets that have given Purdue flexibility to meet the energy needs of the campus. 2.3 DEMAND SIDE MANAGEMENT APPROACH Purdue University Staff had evaluated a number of the buildings on the campus and had the belief that energy use in the buildings could be decreased through the implementation of energy improvement projects. The amount of energy savings potential across the entire campus was not known, but it was believed to be a significant amount. The approach to determine the energy savings potential across the entire campus was as follows: Demand Side Management Survey The first step in the process was to survey selected buildings that were representative of the entire campus. A Demand Side Management Survey develops information regarding operations, maintenance procedures and energy consumption patterns at the facilities selected for survey as part of the CEMP. The facilities were investigated with a focus on developing conservation opportunities that would provide an overall reduction in the facilities annual energy consumption. Purdue University 2-2 Burns & McDonnell

30 Comprehensive Energy Master Plan FINAL DRAFT 2.0 Introduction Buildings throughout Purdue s West Lafayette campus were selected for inclusion in the facility energy demand assessments. Based on development of a representative list of University facilities, the following locations were selected for survey based on discussions with Purdue staff: Young Hall Hovde Hall of Administration Mechanical Engineering Krannert Building Electrical Engineering Hansen Life Sciences Research Building Lynn Hall McCutcheon Residence Hall These facilities represent four building categories and 8% of the gross campus building footprint. The results of the building analysis are developed on a facility by facility basis and are further extrapolated to represent likely conditions throughout the remainder of the campus facilities. Building energy assessments were performed in eight Purdue campus facilities. The energy assessments were conducted following the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Level II audit recommendations as procedural guidelines for the demand side observations. Following the review of these initial eight buildings, Forney Hall of Chemical Engineering and Heine Pharmacy Building were audited, focusing on the potential impact to the peak heating and cooling load for the campus and that effect on the distribution system Evaluation of Energy Conservation Measures (ECMs) Results from the building survey were developed in the form of Energy Conservation Measures (ECMs). Implementation costs and annual cost savings were calculated for each ECM based on the actual operating conditions and expected implementation process. Each facility selected and surveyed as part of the CEMP has ECMs with associated implementation cost and projected savings. This Report provides a building specific description of system operations and a summary of the applicable ECMs for each facility. Purdue University 2-3 Burns & McDonnell

31 Comprehensive Energy Master Plan FINAL DRAFT 2.0 Introduction Opportunities to reduce energy and water consumption were developed for specific opportunities throughout the campus. For each opportunity a corresponding cost of implementation and savings projection was developed Extrapolation of the Results to Campus The savings and costs accrued at each building by the ECMs were determined so a campus wide extrapolation based on building type could be developed. The basis of extrapolation is that the ECMs are repeatable throughout the campus Development of an Implementation Plan The final step in the process is the development of an implementation plan that addresses the logistics to implement campus wide energy savings projects in a way that provides the best return on investment for Purdue. 2.4 DISTRIBUTION APPROACH Purdue has previously analyzed the chilled water and steam distribution systems on campus. The approach to evaluate the distribution systems was to convert Purdue s existing distribution models to models developed in Applied Flow Technologies (AFT) software Steam The geometric information from the campus GIS system for the piping networks and building steam demands provided by Purdue University was inputted into AFT Arrow. The model was reviewed with Purdue and clarification was provided to specific areas. The AFT Arrow model was then calibrated to existing conditions with information provided by Purdue. Finally optimal routing was determined by analyzing three options for new or extended utility distribution systems that allow for flexibility during the future growth and changes in requirements Chilled Water The geometric information from the campus GIS system for the piping network and building chilled water demands provided by Purdue University was inputted into AFT Fathom. The model was reviewed with Purdue and clarification was provided in specific areas. The AFT Fathom model was then calibrated to existing conditions with information provided by Purdue. Finally optimal routing was determined by Purdue University 2-4 Burns & McDonnell

32 Comprehensive Energy Master Plan FINAL DRAFT 2.0 Introduction analyzing three options for new or extended utility distribution systems that allow for flexibility during the future growth and changes in requirements. 2.5 PRODUCTION APPROACH The approach to analyzing the production options for Purdue began by comparing current production capacities and future demand requirements for electricity, chilled water and steam. This analysis highlights areas when additional loads on campus will exceed the production capacities requiring Purdue to make capital investments to provide capacity for growing utility demands. This information was presented to Purdue and four production areas were selected for further analysis. It should be noted that the TES/CHP Feasibility Study included a high level review of Thermal Energy Storage and the Level II CHP Feasibility and Fiscal Impact Assessment Study included a detailed review of the production requirements to meet steam demand. Therefore the following items were selected: Chilled Water Road Map: Develop a road map for the entire chilled water system including retirement of chillers and meeting increased chilled water demand. Curtailment Analysis: Investigate the requirements to allow Purdue to remove the current operating procedure of curtailing steam and chilled water demand at the buildings during peak times. Future Satellite Chilled Water Plant: Analyze a location or locations for the future satellite chilled water plant and determine the size, cost and facility implementation schedule. Auxiliary Components: Investigate the economic implications of utilizing steam driven auxiliary components or electrically driven assets at the Wade Utility Plant. * * * * * Purdue University 2-5 Burns & McDonnell

33 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management 3.0 DEMAND SIDE MANAGEMENT Comprehensive energy investigations was conducted on eight representative buildings on the Purdue University campus. The eight selected facilities represent the following campus facility types: Administrative, Classroom, Research/Labs, Dorm/Residence Hall. These facility types comprise the majority of Purdue s campus building stock and provide a sampling of buildings from which to predict energy and operational performance across the rest of campus. Excluded facility types were designated as Other (described as maintenance, utility and grounds), Parking Garage and Sports/Recreation facilities. The investigation of the representative facilities was initiated to develop a baseline of the energy savings potential that exists across the select campus facilities with respect to utility consumption (domestic water, chilled water, steam, and electricity). Interviews were conducted of Purdue Facility Staff, existing information was reviewed and site investigations were performed on the selected facilities. Based on development of a representative list of University facilities, the following facilities were selected for investigation: Young Hall Hovde Hall of Administration Mechanical Engineering Krannert Building Electrical Engineering Hansen Life Sciences Research Building Lynn Hall McCutcheon Residence Hall ASHRAE Level II Energy Assessment Procedures were utilized in conducting the building surveys. Building systems reviewed as part of the Assessment included mechanical and electrical systems, steam distribution, lighting systems, domestic water systems, HVAC systems and building automations systems. University facilities were investigated between the months of June and August University personnel responsible for the facility maintenance and most familiar with the particular day-to-day operation of the facilities accompanied the investigation team. Through observations, interviews and discussions with operators and facility occupants, a summary list of Energy Conservation Measures (ECMs) was developed. The ECMs represent specific energy savings opportunities with a reasonable Purdue University 3-1 Burns & McDonnell

34 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management payback and are projected to be repeatable across multiple campus facilities. The ECMs are generally items requiring revision of operational parameters, installation of control system components or reprogramming of software systems. Items not selected for consideration as ECMs in this Plan include those items requiring major renovation or retrofit, architectural renovation, renewable energy systems, and distributed generation systems. These items were not considered due to their typical extended project payback performance. Costs and saving attributes for individual ECMs were quantified for the specific conditions found in each facility as described in Section through Section In each building analyzed, cost and savings were determined on an individual basis for each ECM developed. Summary implementation costs presented in tables throughout Sections to Section are the summary total of all ECMs developed for the particular facility. The ECMs are discussed in detail in Sections 3.8 and BUILDING SELECTION Representative facilities were selected from a Purdue University zone maintenance summary list. The summary list includes the active facilities under the University s zone maintenance program. Dormitory and/or residence life facilities were added to the buildings on the zone maintenance summary to provide a total of approximately 263 facilities totaling 16,800,000 ft 2 to be considered for the demand side analysis. Based on an interactive selection process which identified a representative sampling of campus facilities regarding classification and age, the following facilities in Table 3-1 were selected for inclusion in the demand side building analysis. Table 3-1: Selected Buildings for Demand Side Evaluation Facility Gross Area (ft 2 ) Classification Year of Construction Young Hall 214,900 Administration 1962 Hovde 76,700 Administration 1935 Mechanical Engineering 136,900 Classroom 1929 and 1948 Krannert 179,800 Classroom 1963 (Krannert) Electrical Engineering 154,900 Classroom 1923 and 1940 Hansen 106,400 Research/Lab 1983 Lynn 200,000 (est.) Research/Lab 1993 and 2005 additions McCutcheon 209,200 Dormitory 1962 Purdue University 3-2 Burns & McDonnell

35 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management The selected buildings represent four categories and represent approximately 8% of the gross campus building area of 16,800,000 ft 2. The results of the building analysis are developed on a facility by facility basis and are further extrapolated to estimate the magnitude of costs and savings associated with implementing the energy conservation opportunities throughout campus. 3.2 INVESTIGATION PROCEDURE Building energy assessments were performed in eight Purdue campus facilities. The assessments were conducted following the ASHRAE Level II audit recommendations as procedural guidelines. The energy investigations were conducted with the following activities: Review available building information such as facility floor plans, control sequences, facility bible plans and equipment schedules. Perform on site investigations of each selected facilities mechanical, electrical, steam distribution, lighting, plumbing (domestic water and compressed air), and building automation/control systems. Discuss with building operations personnel the ongoing maintenance procedures and recurring operational and/or maintenance issues. Discuss building comfort, hours of operation, and occupancy patterns with building operations personnel and occupants. Develop Energy Conservation Measures (ECMs) including each ECMs applicable installation cost and annual utility savings. 3.3 GENERAL BUILDING OBSERVATIONS The majority of buildings on campus and each building surveyed in this CEMP are supplied with electricity, chilled water, steam, and compressed air from central utility plants on campus. The utilities are generally not accurately metered at the building level, but the University is currently conducting a building by building program to install meters in the buildings. Throughout the facilities, interior lighting typically consists of T8 linear and compact fluorescent fixtures which are manually controlled by occupants. The University previously completed lighting retrofit projects in many of the facilities resulting in efficient lighting technology with minimal opportunity for improvements. In most facilities surveyed, the water fixtures installed are high flow devices presenting many opportunities for water conservation throughout the campus. Purdue University 3-3 Burns & McDonnell

36 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Opportunities to reduce facility energy consumption and demand were observed in each of the surveyed facilities. However, the impact of the opportunity varies greatly between the buildings and throughout the building types surveyed. Observations developed as part of the survey in conjunction with interview of building operators, occupants and the University s facility operations team includes the following items: Zone maintenance personnel could benefit from additional training and access to the building automation system to correct building operational issues. Maintenance personnel are reliant on the Building Systems Group for system troubleshooting. New Lab/Research spaces on campus maintain a minimum occupied air exchange rate of six Air Changes per Hours (ACH). Opportunities exist in selected existing labs to reduce the air change rate during occupied and unoccupied times while offering significant reductions in energy. Our understanding is that Purdue is currently working to reduce air change rates in labs during unoccupied times. Space temperature set back is currently not utilized in a majority of campus locations. Rooms that have varying occupancy patterns based on academic calendar, occupancy and/or scheduled events and do not have a regular occupancy schedule have a high opportunity for energy savings. Most of the campus facilities that were investigated currently utilize high flow water devices (urinals, faucets, toilets, etc). There are numerous opportunities to save water by retrofitting these fixtures with low flow devices. 3.4 SPECIFIC BUILDING OBSERVATIONS This section contains a brief summary of the mechanical systems encountered in each facility and table providing the ECMs identified for each facility. Purdue University 3-4 Burns & McDonnell

37 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Young (Ernest C.) Hall Young Hall is a 214,900 ft 2 office building constructed in 1962, and was originally a dormitory. The building is located in Maintenance Zone 4. The HVAC system is separated into two main sections: the basement and first floor, and nine above-ground floors. The basement and lower floors are served by one Multi-Zone (MZ) AHU and one Dual-Duct (DD) AHU located in the basement. The other floors are served by individual room induction units, which receive conditioned fresh air from two high-pressure AHUs in the penthouse. Exhaust air from the bathrooms on each floor is collected for each wing and exhausted by two large fans in the penthouse. The building chilled water distribution is supplied from the campus chilled water (CHW) distribution system which is augmented by a variable speed booster pump in the basement. The chilled water is supplied to all four AHUs before entering the dual-temp heat exchangers, which provide cooling for the two building chilled water loops during the cooling season. Alternatively, the building water loops are heated during heating seasons via heat exchangers with steam from the campus loop. The building water loops are circulated through the room induction unit coils with two manually controlled Variable Frequency Drive (VFD) equipped pumps. Steam provides the energy source for AHUs in the heating mode. Campus CHW and steam enters the building in the basement. Both CHW and steam have Btu meters installed. The CHW meter has a local GE module with readout. The steam condensate meter is connected to the Building Automation System (BAS) Young Hall Recommended ECMs ECMs developed for Young Hall are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Purdue University 3-5 Burns & McDonnell

38 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Table 3-2: Young Hall Recommended ECMs ECM YOUNG Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 01 Convert Multi-Zone AHU to VAV Bsmt MZ AHU 38, , $ 90,500 $ 3, Convert Dual-Duct AHU to VAV Bsmt DD AHU 32, , $ 97,500 $ 2, New Space Temp Sensors with 2 Bsmt Scheduling & Occupancy AHUs 1, , $ 59,500 $ 2, Air-Side Heat Recovery on Exhaust Air 2 PH AHUs -11, , $ 75,600 $ 3, Eliminate Simultaneous Heating and Cooling 2 PH AHUs 0 1,672 31, $ 7,000 $ 9, * Insulate Steam Condensate Piping $ 7,900 $ 1, * Disable Steam Humidifiers in Off- Season , $ 4,200 $ * Change Air Filters - 65, $ 700 $ 3, * Low Flow Water Fixtures $ 72,200 $ 11, * Schedule Equipment Off (Computers) - 14, $ - $ 700 TOTAL 141,275 3,633 79, $ 415,100 $ 39,100 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified with a corresponding payback are as follows: The design of the majority of the building with induction air units in each room does not match the current use of office space. It results in over-ventilated spaces because of the fresh air delivered by the Penthouse AHUs. However, due to the uncertainty concerning the future use of many of the floors, it is recommended that this system be left in its current state. Once the future use is known the applicability of this system for new occupancy should be reviewed. [ECM-22] There was some moderate duct leakage in the penthouse on the supply ducts from the two AHUs. The high pressure supply results in more CFM per duct penetration, and these should be sealed to prevent leaks. [ECM-26] The CHW energy meter in the basement, common to many of the buildings audited, is installed using strap-on ultrasonic transducers and temperature probes. This method of flow and temperature measurement is not accurate and should be improved. Purdue University 3-6 Burns & McDonnell

39 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Hovde (Frederick L.) Hall of Administration In 1935 the 76,700 ft 2 Purdue Executive Building was opened to house administration offices. Frederick L. Hovde was president of Purdue from 1946 until his retirement in 1971, after which time the Purdue Executive Building was renamed the Frederick L. Hovde Hall of Administration. The building is located in Maintenance Zone 2. Hovde Hall is a four story building not including basement and attic levels that primarily house mechanical and electrical equipment. Chilled water is supplied to the basement equipment room from the campus chilled water distribution system. The chilled water is circulated by pumps in Elliot Music Building. Both the ground and first floors are served by a variable volume (VAV) AHU. The Provost Office area on the first floor is served by a constant volume (CAV) dual duct (DD) AHU with 12 zones. The main office areas on the second floor are served by a VAV single duct (SD) AHU. The first floor main office area, the second floor large conference room and board room, and the president s office are all served by separate single zone CAV AHU. The entire third floor is served by a CAV multi-zone (MZ) AHU. All of the AHUs have steam heating and chilled water cooling except the unit serving the president s office which has direct expansion (D/X) cooling. There is a general exhaust fan (GEF) in the attic that relieves air from the restrooms and plenums in the building Hovde Hall Recommended ECMs ECMs developed for Hovde Hall are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Purdue University 3-7 Burns & McDonnell

40 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Table 3-3: Hovde Hall Recommended ECMs ECM HOVDE Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 01 Convert Multi-Zone AHU to VAV ACA-1 in Attic 41, , $ 89,000 $ 3, Convert Dual-Duct AHU to VAV AC1-13 5, , $ 6,400 $ New Space Temp Sensors with Scheduling & Occupancy 03 Air-Side Economizer - AHU Modification 06 Eliminate Simultaneous Heating and Cooling 13 Replace IGVs with Fan VFDs 16 Static Pressure Reset on VAV AHUs and Exhaust AC's 1,2,5,13 3, , $ 64,400 $ 4,600 ACB-5 in Bsmt ACA-2 and ACB-5 ACA-2 and ACB-5 ACA-2 and ACB , $ 10,500 $ , $ - $ 3,000 30, $ 40,200 $ 1,400 8, $ - $ * Insulate Steam Condensate Piping $ 2,800 $ * Disable Steam Humidifiers in Off- Season , $ 1,500 $ * Change Air Filters - 23, $ 200 $ 1, * Low Flow Water Fixtures $ 25,800 $ 4, * Schedule Equipment Off (Computers) - 5, $ - $ 200 TOTAL 118,080 1,459 74, $ 240,800 $ 20,100 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified in with a corresponding payback are as follows: [ECM-20] Several of the CHW valves on AHUs in the attic are three-way way valves with the bypass leg isolated. This is an inexpensive conversion from a three-way valve to two-way, resulting in conserved CHW flow and increased ΔT. However, three-way valves are not designed for close-off pressure like two-way valves. This commonly results in poor flow control through the coil and valve hunting. [ECM-11] AC1-13 has no capability to air-side economize and therefore uses CHW year-round to cool its spaces. Depending if this unique situation exists in other buildings on campus, it could be beneficial to install a plate-and-frame heat exchanger at the Wade plant to provide CHW to users during cool outdoor air periods without running chillers. All the AHUs currently run 24/7 although staff indicated schedules were formerly used. ACA-2 has a steam leak in the coil that should be repaired. Purdue University 3-8 Burns & McDonnell

41 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Mechanical Engineering The School of Mechanical Engineering was founded in 1882 and in April of 1930, the Mechanical Engineering Building was opened. Since then the building has had renovations in 1932, 1942, 1948, 1980 and An addition to the Mechanical Engineering Building called the Roger B. Gatewood Wing was recently dedicated. The Gatewood Wing is the first Purdue building constructed to Leadership in Energy and Environmental Design (LEED) standards. The Mechanical Engineering Building is 136,900 ft 2 and houses offices, classrooms, and research laboratories. Mechanical Engineering is a four story building along with basement and attic level mechanical and electrical spaces. The building is located in Maintenance Zone 2. The chilled water and steam for the building enters through the basement mechanical room. The chilled water system has two building chilled water pumps along with a bypass valve for flow and temperature control in the building. All of the AHUs have steam heating coils. There is a steam to hot water converter in the basement that supplies terminal units on the ground floor and building radiation. The northwest offices and classrooms on the ground, first, second, and third, floors are served by two variable volume (VAV) single duct air handling units (AHU) that are cooling only. More offices on the ground floor are served by one constant air (CAV) dual duct (DD) AHU that is 100% return air. There are 15 shops/labs in the west wing of the ground floor that are served by a VAV single duct AHU that is 100% outside air and 17 variable air volume terminal units with hot water reheat. The large classroom and maintenance bay on the first floor are served by separate CAV single duct AHUs. The offices on the first floor are served by a VAV single duct AHU that is cooling only. There is a cooling only Liebert unit on the second floor providing cooling. The building has a number of fan coil units providing supplemental cooling and heating to a number of spaces throughout the building. Purdue University 3-9 Burns & McDonnell

42 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Mechanical Engineering Recommended ECMs ECMs developed for Mechanical Engineering are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Table 3-4: Mechanical Engineering Recommended ECMs ECM MECHANCIAL ENGINEERING Unit(s ) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 09 New Space Temp Sensors with Scheduling & Occupancy AC's 3,5,6,10 5, , $ 338,100 $ 7, Air-Side Economizer - BAS Sequencing 2 Big PH AHUs , $ 14,000 $ 3, Convert 100% Fresh Air AHU to Mixed ACA-10 Air Outside 0 2,880 77, $ 94,500 $ 17, Eliminate Simultaneous Heating and Cooling AC , $ 1,400 $ Replace IGVs with Fan VFDs 2 Big PH AHUs 53, $ 37,300 $ 2, * Insulate Steam Condensate Piping $ 5,000 $ 1, * Disable Steam Humidifiers in Off- Season , $ 2,700 $ * Change Air Filters - 41, $ 400 $ 2, * Low Flow Water Fixtures $ 46,000 $ 7, * Schedule Equipment Off (Computers) - 9, $ - $ 400 TOTAL 110,150 4, , $ 539,400 $ 42,200 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified in with a corresponding payback are as follows: There is approximately 800 cfm of conditioned outside air from ACA-10 that serves a basement mechanical room. This register blows air down the stairs, but does not seem to reach the lower area where the cooling load exists. [ECM-12] Insulating steam components and using transfer air instead of primary air would reduce energy usage to cool this area. This is a high-temperature safety hazard and should be identified and remedied as soon as possible. ACA-10, which sits outside on the ground, is a 100% fresh air unit, although most of the spaces do not require 100% fresh air. Although the conversion [ECM-08] of this AHU to re-circulation should be simple considering the existing return/exhaust air ductwork, consideration should be given to the machine shop served, as it has tight humidity requirements. The CHW pump serving ACA-10 has no bypass as other building pumps do. Installing a bypass with check valve would allow the AHU to run on plant pressure instead of constantly pumping. Purdue University 3-10 Burns & McDonnell

43 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Krannert Building The 179,800 ft 2 Krannert Building was built in 1965 after a donation from Herman and Ellnora Krannert. The Krannert Building is an eight story building that houses offices, classrooms, and computer labs. The building is located in Maintenance Zone 4. The building chilled water system consists of a secondary pump along with a plate and frame heat exchanger and booster pump. The campus chilled water enters the building in the basement and is supplied to the basement air handling units (AHU) and the heat exchanger. From the heat exchanger the chilled water is supplied to the penthouse AHUs and the fan coil units. The fan coil units have dedicated dual temperature pumps and a steam to hot water heat exchanger for winter mode. If the chilled water measured leaving the fan coil units is below 63 F, there is a three-way control valve that will mix the penthouse AHU return water with the supply water to bring return water temperature up to setpoint. When the system is in winter mode, the fan coil loop is isolated and steam to hot water converter is enabled. All of the AHUs have steam heating coils, but there is a steam to hot water converter for the fan coil units throughout the building. The basement and first floor offices and classrooms are supplied by four constant air (CAV) multi-zone (MZ) AHUs. Floors two thru seven are supplied by CAV dual duct (DD) AHUs. The seventh floor also has four supplemental heating and cooling units for different areas including a unit with a secondary chiller. The Krannert Center is a two story 31,251 ft 2 building that was opened in 1983 and has two large arenastyle classrooms and many smaller meeting areas. The first floor is served by two CAV AHUs. The second floor and part of the first floor are served by a variable air volume (VAV) AHU which serves spaces that have individual VAV terminal units controlled by a local thermostat. Purdue University 3-11 Burns & McDonnell

44 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Krannert Building Recommended ECMs ECMs developed for the Krannert Building are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Table 3-5: Krannert Building Recommended ECMs ECM KRANNERT Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 01 Convert Multi-Zone AHU to VAV 4 Bsmt AHUs, ,2,3,4 159, ,898 $ 346,000 $ 13, New Space Temp Sensors with All AHUs exc Scheduling & Occupancy 10,11 11,121 2,133 96,587 $ 462,000 $ 18, Air-Side Economizer - AHU 4 PH AHUs, Modification 6,7,8,9 56, ,476 $ 143,000 $ 7, * Insulate Steam Condensate Piping $ 6,600 $ 1, * Disable Steam Humidifiers in Off- Season , $ 3,500 $ * Change Air Filters - 54, $ 600 $ 2, * Low Flow Water Fixtures $ 60,400 $ 9, * Schedule Equipment Off (Computers) - 12, $ - $ 600 TOTAL 294,405 3, , $ 1,022,100 $ 54,100 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified in with a corresponding payback are as follows: Although the attic AHUs are mostly dual-duct configuration, the quantity of zones and mixing boxes makes a VAV conversion not economical. An algorithm that takes instantaneous temperatures and duct flows should be implemented to reset mixed air temperature and hot/cold duct temperature setpoints to optimize energy usage. Much of the perimeter space is served by 2-pipe fan-coil units, which heat and cool to the same thermostat as the mixing boxes from the attic dual-duct AHUs. This setup allows the possibility for the FCUs and mixing boxes to be fighting each other if the thermostat becomes out-of-calibration. The dual-temp pumps in the basement have VFDs for soft-start, but are on/off. Because the FCU water control valves are two-way, these pumps are forced to ride their curve. Using the VFD to maintain speed and pressure can result in pump energy savings. Purdue University 3-12 Burns & McDonnell

45 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Electrical Engineering The Electrical Engineering Building is four stories and was built in In 1932 the Duncan Annex was the first addition to the Electrical Engineering Building. The Electrical Engineering Building had a major renovation in 1940 and the estimated size of the building is 154,900 ft 2. The building is located in Maintenance Zone 3. Chilled water is supplied to the main Electrical Engineering Building in the basement and the chilled water system has dual variable volume building chilled water pumps to control the flow through the building. The Duncan Annex has its own chilled water service with a single variable volume distribution pump and return water modulating control valve to control chilled water flow and temperature in the building. The Electrical Engineering Building and Duncan Annex have 35 air handling units (AHU) throughout the space with chilled water coils and steam heating coils. The basement and first floor of the Duncan Annex are served by four constant volume (CAV) AHUs that have a dedicated outside air unit located in the third floor attic. The first, second and third floors of Duncan Annex are served by two CAV multi-zone (MZ) AHUs. One has a direct outside air unit in the attic and serves the office area; the other unit serves two large lecture halls. The ground floor in the Electrical Engineering Building is supplied by a CAV multi-zone AHU and two CAV single-duct AHUs. The first floor offices and classrooms are served by three CAV multi-zone AHUs, one CAV single-duct AHUs, and two CAV dual-duct AHUs. There is a CAV single-duct AHU that serves a large auditorium on the first floor. The southwest portion of the second floor is currently under construction and five AHUs were being removed and replaced with one variable air volume (VAV) single duct AHU. The rest of the classrooms and offices on second floor are served by three CAV singleduct AHUs, and three CAV multi-zone AHUs. One of the multi-zone units has seven VAV terminal units with local control. The third floor is supplied by one CAV multi-zone AHU, one CAV dual-duct AHU, and two CAV single-duct AHUs. One of the CAV single-duct AHUS serves 48 rooms on the third floor. Purdue University 3-13 Burns & McDonnell

46 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Electrical Engineering Recommended ECMs ECMs developed for Electrical Engineering are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Table 3-6: Electrical Engineering Recommended ECMs ECM ELECTRICAL ENGINEERING Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 01 Convert Multi-Zone AHU to VAV 21,22,23,27,28 119, , $ 270,300 $ 9, Convert Dual-Duct AHU to VAV ACG-3 & ACA-26 40, , $ 248,900 $ 3, New Space Temp Sensors with Scheduling & Occupancy 1-3,5,8-11,21-23,26-28, 35, 43 5,721 1,097 49, $ 189,000 $ 7, Air-Side Economizer - BAS Sequencing ACA , $ 2,800 $ Convert 100% Fresh Air AHU to Mixed Air 06 Eliminate Simultaneous Heating and Cooling Liebert , $ 14,000 $ 4,600 ACG-2,5, ACA ,012 59, $ - $ 7, * Insulate Steam Condensate Piping $ 5,700 $ 1, * Disable Steam Humidifiers in Off- Season , $ 3,000 $ * Change Air Filters - 47, $ 500 $ 2, * Low Flow Water Fixtures $ 52,000 $ 8, * Schedule Equipment Off (Computers) - 10, $ - $ 500 TOTAL 224,248 4, , $ 786,200 $ 46,400 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified in with a corresponding payback are as follows: [ECM-12] Much of the condensate piping in the building is un-insulated, including that in classrooms. This is a high-temperature safety hazard and should be identified and remedied as soon as possible. Insulating the condensate piping everywhere will result in steam savings and increased safety for occupants. There are several separate steam systems in the building, all of which are active year-round. Some perimeter heating loops should be able to be shut off in the summer months. ACG-3 s minimum fresh air dampers did not operate when stroked and should be commissioned to provide economizing during free-cooling hours. ACA-44 should be de-commissioned and replaced with a smaller system designed to serve the new computer room. Purdue University 3-14 Burns & McDonnell

47 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management [ECM-09] During the audit, the auditorium was empty and dark, but a significant amount of air was exhausting from the space. This is due to the constant space temperature and ventilation setpoints, regardless of occupancy Hansen (Arthur G.) Life Sciences Research Building Hansen Hall is a five story, 106,400 ft 2 research building which opened in The building is located in Maintenance Zone 8. Hansen has four primary types of HVAC systems. The basement animal holding and vivarium areas are served by a single-pass 100% outside air system with an exhaust heat recovery system located in the basement. The basement is exhausted by a single exhaust system that includes the heat recovery loop. The common and support areas (offices, classrooms, etc) on the first floor and the central core of the second, third and fourth floors are served by recirculating VAV air handling units located in the basement and on first floor. The corridor on each floor is served by a 100% outside air unit with no return. The corridors are pressurized in relation to the labs to prevent migration of gases and fumes. The perimeter areas of second, third and fourth floors are populated by multiple lab modules, six per floor. Each perimeter lab module is served by a dedicated 100% outside air handling unit and a general exhaust fan. The second floor is Constant Air Volume (CAV) and the third and fourth floors are Variable Air Volume (VAV). Each fume hood exhaust service, in the perimeter labs, is served by a small dedicated exhaust fan on the roof (which results in dozens of exhaust fans on the roof). Each of these exhaust systems include a VFD controller to maintain the room pressurization. All AHU s have chilled water cooling and steam heating supplied by the campus central plants. A steam-to-hydronic hot water heat exchanger is utilized for zone level reheat Hansen Life Sciences Recommended ECMs ECMs developed for Hansen Life Sciences are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Purdue University 3-15 Burns & McDonnell

48 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Table 3-7: Hansen Life Science Building Recommended ECMs ECM HANSEN Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 09 New Space Temp Sensors with ACB Scheduling & Occupancy ,059 $ 16,800 $ 1, Air-Side Heat Recovery on Exhaust Air AHUs ,763 5,935 19, $ 500,900 $ 24, Reduce ACH Rates in Unoccupied Lab See Comment Spaces 132,211 1,976 49,026 $ 59,700 $ 17, Air-Side Economizer - AHU AC1-4 and Modification other 0 0 5,513 $ 5,600 $ * Insulate Steam Condensate Piping $ 3,900 $ * Disable Steam Humidifiers in Off- Season , $ 2,100 $ * Change Air Filters - 32, $ 300 $ 1, * Low Flow Water Fixtures $ 35,700 $ 5, * Schedule Equipment Off (Computers) - 7, $ - $ 300 TOTAL 82,939 8,252 87, $ 625,000 $ 52,300 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified in with a corresponding payback are as follows: The multiple exhaust fans on the roof should be replaced by larger manifold exhaust systems. The manifolded exhausts should incorporate a heat recovery loop. The heat recovery loop should be connected to the perimeter 100% OA units. To improve the static pressure impact, the installation should also include a bypass of the heat recovery coils for mild outside air temperatures. Install occupancy sensors in each lab room to reduce air change rate and lighting when room is unoccupied. Continue fume hood sash management program with energy awareness stickers. (see photo below) Purdue University 3-16 Burns & McDonnell

49 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Lynn (Charles J.) Hall (1993 and 2005 sections) Areas of the building constructed in 1993 and 2005 were considered in the survey. The applicable spaces in Lynn Hall are approximately 200,000 ft 2 and are home to research functions and the School of Veterinary Medicine. Lynn was originally built in 1958 with a major addition in 1993 and Lynn Hall was named after Charles J. Lynn, a pharmaceutical company executive and philanthropist. The building is in Zone 5. Lynn is broken into five wings, A thru E. This project s scope includes only wings A, B and C. The basement, under A and B only, is primarily mechanical space. Wing A is primarily classrooms, offices, and common support areas on ground, main and second floors, and is primarily mechanical space in the basement. Wing B is veterinary clinic and surgery on the main floor, labs on the main floor, with mechanical space in the basement and on second (a roof penthouse). Wing C is a single story on ground floor with a mechanical penthouse. The Wing C ground floor includes support areas for the veterinary clinic including the veterinary lab, and animal holding. Lynn has two primary types of HVAC systems. The critical areas (the labs, the surgery area, and the veterinary areas) are 100% outside air with manifolded exhaust systems. The labs and the animal holding area include exhaust heat recovery systems. The units serving the veterinary clinical lab and three surgery areas are designed for recirculation, but the units are balanced to 100% OA at all times. The common and support areas (offices, classrooms, and library) are served by recirculating VAV systems. All AHU s receive cooling from the campus chilled water (CHW) system and utilize the campus Steam system for preheating. A steam-to-hydronic hot water heat exchanger is utilized for zone level reheat Lynn Hall Recommended ECMs ECMs developed for Lynn Hall are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Purdue University 3-17 Burns & McDonnell

50 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Table 3-8: Lynn Hall Recommended ECMs ECM LYNN Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 07 Reduce ACH Rates in Unoccupied Lab AC Spaces 16, ,044 $ 19,600 $ 2, Convert 100% Fresh Air AHU to Mixed ACB-30,31, Air ACM ,285 61,666 $ 56,000 $ 8, New Space Temp Sensors with AC's 28, Scheduling & Occupancy 1, ,197 $ 61,600 $ 2, Eliminate Simultaneous Heating and AC Cooling ,113 $ - $ 1, Static Pressure Reset on VAV AHUs MHER and Exhaust Strobic 52, $ - $ 2, * Insulate Steam Condensate Piping $ 7,400 $ 1, * Disable Steam Humidifiers in Off- Season , $ 3,900 $ * Change Air Filters - 61, $ 600 $ 2, * Low Flow Water Fixtures $ 67,200 $ 10, * Schedule Equipment Off (Computers) - 13, $ - $ 600 TOTAL 145,332 3, , $ 216,300 $ 33,600 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. Other observations that were not quantified with a corresponding payback are as follows: The veterinary and surgery areas are not required by code to have single-pass 100% outside air systems (excluding the animal holding area). These should be converted to a re-circulating system per the requirements of the ASHRAE ventilation standard. The multiple exhaust fans on the roof should be replaced by larger manifold exhaust systems. The manifolded exhausts should incorporate a heat recovery loop. The heat recovery loop should be connected to the perimeter 100% OA units. To improve the static pressure impact, the installation should also include a bypass of the heat recovery coils for mild outside air temperatures. The existing central lab exhaust system in the penthouse is operating at 5 inches static pressure. This is much higher than is anticipated. Fan energy could be dramatically reduced by just rebalancing the system. Install occupancy sensors in each lab room to reduce air change rate and lighting when room is unoccupied. Continue fume hood sash management program with energy awareness stickers. Purdue University 3-18 Burns & McDonnell

51 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management McCutcheon Residence Hall McCutcheon Hall opened in 1963 and was named after John T. McCutcheon. McCutcheon Hall is 209,200 ft 2 and houses dorm rooms, conference rooms, computer labs, and a dining facility. McCutcheon has two 8 story dorm room towers that are connected by a common 2 story student center. The building chilled water system consists of a secondary pump along with a plate and frame heat exchanger and two secondary pumps serving the high rise fan coil units. All of the AHUs cooling coils are served directly by the campus chilled water, and the high fan coil units are served through the heat exchanger. All of the AHUs have steam heating coils supplied by the campus central plant. Dorm rooms utilize fan coil units for cooling and steam radiators for heating. There are two constant air volume (CAV) make-up air handling units (AHU) in the towers that supply air to the corridor on each floor to provide fresh air to the rooms. The units are equipped with D/X cooling and dehumidification control. The common student center is served by two CAV AHUs which have a dedicated outside air unit. The owner has indicated that there is a project in progress to replace these AHUs. The building is being maintained by Housing and Food Service Facilities maintenance. Purdue University 3-19 Burns & McDonnell

52 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management McCutcheon Residence Hall Recommended ECMs ECMs developed for McCutcheon Residence Hall are provided in the following table. The ECMs represent opportunities to reduce energy and water consumption. These recommendations are based on observations gathered during the site investigations. Table 3-9: McCutcheon Residence Hall Recommended ECMs ECM MCCUTCHEON Unit(s) Annual Energy Savings Annual Demand Savings Installed Annual # ECM Identification Affected kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings 17 Optimize DAT/RH from Make-Up Air 2 Roof DX AHUs MAU's 72, $ 16,800 $ 3, Air-Side Heat Recovery on Exhaust Air 2 Roof DX MAU's -14, , $ 70,000 $ 2, * Insulate Steam Condensate Piping $ 7,700 $ 1, * Disable Steam Humidifiers in Off- Season , $ 4,100 $ * Change Air Filters - 63, $ 700 $ 3, * Low Flow Water Fixtures $ 70,300 $ 11, * Schedule Equipment Off (Computers) - 14, $ - $ 700 TOTAL 136,637 1,369 17, $ 169,600 $ 23,800 Table Notes: See Sections 3.8 and 3.9 for ECM descriptions. ECMs indicated by (*) were developed on a project total basis and extrapolated on a building square foot basis. DAT = Discharge Air Temperature; RH = Relative Humidity Other observations that were not quantified in with a corresponding payback are as follows: ACP-2 and ACP-3 are slated for replacement due to age and condition. The current design proposes to replace the units in kind, with an option to combine the units into one. The air distribution remains as is: constant volume, multi-zone. It is recommended that these units be replaced with VAV AHUs, similar to ECM-01. The two roof make-up-air AHUs deliver a constant volume of air to each floor year-round. It could be economical to install VAV dampers on each floor s register and modulate the airflow based on temperature, humidity, and ventilation requirements in the space. This would reduce airflow during unoccupied times. Purdue University 3-20 Burns & McDonnell

53 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management 3.5 SUMMARY OF RESULTS A summary of the impact from the eight facilities surveyed as part of the study are compiled in the following table. These results are the aggregate of incorporating all ECMs developed for each facility. Table 3-10: Summary of Building Survey Results Sample Annual Energy Savings Annual Demand Savings Installed Annual By Facility kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings Young Hall 141,300 3,600 80, $ 415,100 $ 39,100 Hovde 118,100 1,500 75, $ 240,800 $ 20,100 Mechanical Engineering 110,100 4, , $ 539,400 $ 42,200 Krannert 294,400 3, , $ 1,022,100 $ 54,100 Electrical Engineering 224,200 4, , $ 786,200 $ 46,400 Hansen 82,900 8,300 87, $ 625,000 $ 52,300 Lynn 145,300 3, , $ 216,300 $ 33,600 McCuthcheon 136,600 1,400 17, $ 169,600 $ 23,800 1,252,900 29, , $ 4,014,500 $ 311, EXTRAPOLATION TO THE CAMPUS Following the assessment of eight campus facilities and the related economic analysis of developed Energy Conservation Measures, an analysis of campus wide benefits was conducted. Through this analysis data developed in the building assessment on a building by building basis is extrapolated to determine the potential impact across specific building types across campus. The impact across the campus is scaled on a building classification basis such that ECM results for each category of facility surveyed are broadly applied to the same classification across campus. Buildings surveyed as part of the Demand Side Management Investigation total approximately 1,300,000 ft 2, and are comprised of four facility types. Extrapolation of energy savings to select Purdue University facilities is conducted on the basis of building classification. Buildings selected for inclusion in the extrapolated set are those facilities exceeding 40,000 ft 2 and are one of the four types of facilities (Administration, Classroom, Research/Laboratory, Dormitory/Residence Hall) selected in the 8 building evaluation set. The facilities selected for inclusion in the extrapolated campus demand side program are as follows in the following tables. Purdue University 3-21 Burns & McDonnell

54 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Table 3-11: Buildings Included in Campus Level Demand Side Management Zone Acronym Building Name Area (ft2) Year of Construction Type of Facility 1 ENAD Engineering Administration Building 54, , 1932, 1937, 1940 Administration 2 HOVD Hovde (Frederick L.) Hall of Administration 76, Administration 2 PUSH Purdue University Student Health Center 58, Administration 2 SCHL Schleman (Helen B.) Hall of Student Services 87, , 1988 Administration 4 YONG Young (Ernest C.) Hall 214, Administration 4 PMU Purdue Memorial Union 258, , 1935, 1938,1962 Administration 4 PMUC Purdue Memorial Union Club 109, , 1938, 1953, 1986 Administration 5 FREH Freehafer (Lytle J.) Hall of Administrative Services 126, , 1987 Administration 7 FOOD Food Stores Building 46, , 1989 Administration 8 AGAD Agricultural Administration Building 65, Administration 8 AR Armory 73, Administration 8 BRNG Beering (Steven C.) Hall of Liberal Arts and Education 205, Classroom 3 CIVL Civil Engineering Building 297, , 1962, 1986 Classroom 7 DLR Hall for Discovery and Learning Research 96, Classroom 3 EE Electrical Engineering Building 154, , 1925, 1930, 1940 Classroom 2 ELLT Elliott (Edward C.) Hall of Music 163, Classroom 1 GRIS Grissom Hall 58, , 1928, 1948 Classroom 2 HAAS Haas (Felix) Hall 50, Classroom 1 HEAV Heavilon Hall 97, Classroom 5 HGRH Horticulture Greenhouses 63, , 1996 Classroom 7 HOCK Wayne T. and Mary T. Hockmeyer Hall Structural Biology 74, Classroom 1 KNOY Knoy (Maurice G.) Hall of Technology 130, Classroom 4 KRAN Krannert Building 179, Classroom 2 LWSN Lawson (Richard and Patricia) Computer Science Building 108, Classroom 7 MANN Mann (Gerald D. and Edna E.) Hall 49, Classroom 8 MATH Mathematical Sciences Building 131, , 1981 Classroom 2 ME Mechanical Engineering Building 136, , 1932, 1942, 1948 Classroom 8 MTHW Matthews (Mary L.) Hall 47, Classroom 8 PFEN Pfendler Hall (David C.) of Agriculture 62, , 2001 Classroom 3 PHYS Physics Building 314, , 1947, 1961, 1967, 1968 Classroom 2 PSYC Psychological Sciences Building 84, Classroom 4 RAWL Rawls (Jerry S.) Hall 125, Classroom 1 REC Recitation Building 41, Classroom 1 SC Stanley Coulter Hall 72, , 1997 Classroom 8 SMTH Smith Hall 67, , 1948, 1972 Classroom 4 STEW Stewart Center 484, , 1933, 1954, 1959 Classroom 8 STON Stone (Winthrop E.) Hall 118, Classroom 5 LSR Life Science Ranges (Greenhouse and Service Building) 81, , 1960, 1998 Classroom 4 HAWK Hawkins (George A.) Hall 286, Dorm/Residence CQE Cary Quadrangle East (CQE) 56,833 Dorm/Residence CQNE Cary Quadrangle, NorthEast (CQNE) 47,180 Dorm/Residence CQNW Cary Quadrangle - Northwest (CQNW) 48,474 Dorm/Residence CQS Cary Quadrangle South (CQS) 173,256 Dorm/Residence CQW Cary Quadrangle West (CQW) 59,036 Dorm/Residence DUHM Duhme Hall 50,359 Dorm/Residence ERHT Earhart Hall 252,629 Dorm/Residence FOOD Food Stores 46,349 Dorm/Residence FORD Ford Dining Court 63,743 Dorm/Residence FSTC FIRST STREET TOWERS, CENTRAL 89,089 Dorm/Residence FSTE FIRST STREET TOWERS, EAST 71,756 Dorm/Residence HARR Harrison Hall 235,599 Dorm/Residence HAWK Hawkins Hall 286,521 Dorm/Residence HILL Hillenbrand Hall 315,070 Dorm/Residence MCUT McCutcheon Hall 209,164 Dorm/Residence Purdue University 3-22 Burns & McDonnell

55 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Table 3-12: Buildings Included in Campus Level Demand Side Management (cont) Zone Acronym Building Name Area (ft2) Year of Construction Type of Facility MRDH Meredith Hall 135,545 Dorm/Residence OWEN Owen Hall 157,220 Dorm/Residence PMU Purdue Memorial Union 258,190 Dorm/Residence PMUC Purdue Memorial Union Club 109,925 Dorm/Residence SHLY Shealy Hall 49,281 Dorm/Residence SHRV Shreve Hall 255,866 Dorm/Residence TARK Tarkington Hall 157,220 Dorm/Residence VAWT Vawter Hall 50,029 Dorm/Residence WARN Warren Hall 62,817 Dorm/Residence WDCT Wiley Dining Court 48,411 Dorm/Residence WILY Wiley Hall 164,560 Dorm/Residence WOOD Wood Hall 55,698 Dorm/Residence 2 ARMS Armstrong (Neil) Hall of Engineering 243, Research/Labs 5 HORT Horticulture Building 66, , 1937 Research/Labs 3 MSEE Materials and Electrical Engineering Building 118, Research/Labs 1 POTR Potter (A.A.) Engineering Center 119, Research/Labs 5 ABE Agricultural and Biological Engineering 60, , 1940 Research/Labs 5 ADDL Animal Disease Diagnostic Lab 60, Research/Labs 8 BCHM Biochemistry Building 99, , 1948, 1976 Research/Labs 7 BIND Bindley (William E.) Bioscience Center 55, Research/Labs 7 BRK Birck Nanotechnology Center 219, Research/Labs 1 BRWN Brown (Herbert C.) Laboratory of Chemistry 216, Research/Labs 2 FRNY Forney Hall of Chemical Engineering 177, , 2002 Research/Labs 8 HANS Hansen (Arthur G.) Life Sciences Research Building 106, Research/Labs 4 HIKS Hicks (John W.) Undergraduate Library 96, Research/Labs 5 LILY Lilly Hall of Life Sciences 389, , 1953 Research/Labs 5 LSA Life Science Animal Building 49, Research/Labs 5 LYNN Lynn (Charles J.) Hall of Veterinary Medicine 339, , 1993, 2005 Research/Labs 1 MGL Michael Golden Engineering Laboratory and Shops 77, , 1947 Research/Labs 7 MJIS Martin C. Jischke Hall of Biomedical Engineering 92, Research/Labs 5 NLSN Phillip E. Nelson Hall of Food Science 126, Research/Labs 2 RHPH Heine (Robert E.) Pharmacy Building 149, Research/Labs 8 WSLR Whistler (Roy L.) Hall of Agricultural Research 93, Research/Labs 1 WTHR Wetherill (Richard Benbridge) Laboratory of Chemistry 252, , 1950 Research/Labs Purdue University 3-23 Burns & McDonnell

56 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management The buildings selected as part of this analysis and their corresponding impact to the overall campus building inventory is as follows: Table 3-13: Building Classifications as a Percentage of Campus Classification Selected Gross Area (ft 2 ) Campus Total (1) (ft 2 ) Percent of Total Campus Selected Administration 291,630 1,171,258 25% Classroom 471,631 3,499,978 13% Research/Lab 306,355 3,209,008 10% Dormitory 209,164 3,796,341 (2) 6% Table Notes: (1) Campus Total (ft 2 ) does not include Other, Parking Garages, and Sports/Recreation Facilities. These building types total approximately 4,800,000 ft 2 and were not selected for inclusion in the building survey. (2) Dormitory does not include Purdue Village and Hilltop Apartments. (3) Buildings less than 40,000ft 2 are not included. Surveyed data is summarized in the following table to provide the energy savings aspects of each category of building surveyed. Table 3-14: Energy Savings by Building Type Sample Annual Energy Savings Annual Demand Savings Installed Annual By Building Type kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings Admin 259,400 5, , $ 655,900 $ 59,200 Classroom 628,800 11, , $ 2,347,700 $ 142,700 Research/Lab 228,300 11, , $ 841,300 $ 85,900 Dormitory 136,600 1,400 17, $ 169,600 $ 23,800 1,253,100 29, , Surveyed data is extrapolated to the entire campus for facilities of similar type (category) as provided in the following table. Table 3-15: Energy Savings Extrapolated to Campus Extrapolation to Campus Annual Energy Savings Annual Demand Savings Installed Annual By Building Type kwh MMBtu Ton-hr kw Tons MMBtu/hr Cost Savings Admin 1,041,600 20, , $ 2,634,500 $ 238,000 Classroom 4,666,400 86,500 4,559, $ 17,422,500 $ 1,059,000 Research/Lab 2,391, ,300 2,073, $ 8,812,500 $ 900,000 Dormitory 2,480,000 24, , $ 3,078,500 $ 432,000 10,579, ,000 7,573, , $ 31,948,000 $ 2,629,000 Purdue University 3-24 Burns & McDonnell

57 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management The following charts provide a comparison of the relative impact of demand savings related to investment dollars for the building types considered. Figure 3-1: Btu/hr Saved per Installed Cost by Building Type Btu/hr/$ 5.0 Peak (Btu/hr) Saved per Dollar Spent Admin Classroom Research/Lab Dormitory Steam Btu/hr per Dollar CHW Btu/hr per Dollar MMBtu/hr Figure 3-2: Peak Energy Savings by Building Type Peak Savings by Bldg Type Admin Classroom Research/Lab Dormitory MMBtu/hr Peak Tons Peak Tons 1,400 1,200 1, ECM ENERGY SAVINGS CALCULATIONS The calculation methods used to estimate savings potential for each ECM were as follows: Bin Temperature Method: Spreadsheet analysis using number of hours in each temperature range (dry bulb, wet bulb, or enthalpy) and calculating energy costs for existing sequences and proposed modifications. This method was most efficient when AHU sequences were translated and programmed into the spreadsheet to mimic the actions of the AHU for each outside air condition or bin Purdue University 3-25 Burns & McDonnell

58 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management equest using DOE-2 Engine: Energy simulation software that allows architectural and mechanical inputs to simulate any type of building in any U.S. location; uses TMY2 file weather data to simulate a typical local weather year. This method was used to produce several sample models of known square footage or design AHU cfm. Results were normalized into metrics such as Saved Btu per 1,000 square feet or cfm. These metrics were used against known areas and air flows to be retrofitted with the ECM modeled. Trane Trace: Energy simulation and design load software similar to equest. This was used to evaluate ECMs impact on cooling peak load reduction Other Spreadsheet Calculations: Spreadsheet analysis using physical formulas to estimate savings for simpler measures not dependent on weather or building loads All calculation methods produced either a) normalized savings metrics, or b) actual savings numbers based on specific equipment operation. The savings metric technique was combined with an exhaustive AHU inventory to apply the savings associated with an ECM to multiple AHUs, areas, buildings, etc. across campus. This method also lends itself to further use in additional buildings. The following savings metrics were utilized: Savings in MMBtu steam, MMBtu/hr steam peak, and Savings in Ton-hrs CHW, Tons CHW peak, and Savings in kwh Electric, kw Electric peak per 1000 sq ft, or 1000 design AHU cfm, or 1 motor hp 3.8 ECM DESCRIPTIONS RECOMMENDED AND EVALUATED The following describes the ECMs with the most significant impact across campus ECM-01: Convert Multi-Zone AHU to VAV A Multi-Zone (MZ) system is a dual path AHU that provides each zone a constant flow of supply air. The temperature of the supply air for an individual zone is controlled by mixing warmer and cooler airstreams at the AHU. The most common configuration is to have a heating coil (hot deck) and a cooling coil (cold deck) in parallel at the AHU. Each zone has a dedicated pair of dampers located at the AHU across the hot and cold deck at the outlet of the unit. An individual duct starting from a set of zone Purdue University 3-26 Burns & McDonnell

59 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management dampers serves each zone. A zone thermostat modulates the zone dampers to mix the hot and cold air streams in varying proportions. Often during cooling periods, the hot deck temperature is reset or inactive and acts as a bypass deck, equalizing with the mixed air temperature. As with most Constant Air Volume (CAV) systems, one of the primary inefficiencies is excess fan motor power consumption. This is especially true with units serving multiple zones. To satisfy space load, the AHU varies the temperature of air delivered to the space. Despite diversity in zone loads, the AHU provides design air flow at all times. In addition, thermal inefficiencies can occur. This is especially true if the coils for both decks are active at the same time. Thermal losses due to air mixing will occur for each zone unless a zone requires supply air at either the hot deck setpoint or cold deck setpoint. This retrofit includes the installation of a VFD on the supply air fan and return air fans (if present). Each zone s mixing damper will become a two-position damper, at any given time open to either the hot deck or cold deck. These dampers shall be inspected for leakage and repaired. In most cases, the existing actuator can be left in service and used as 2-position. Each zone will be retrofitted with a Variable Air Volume (VAV) box in the duct downstream of its hot/cold damper. This VAV box will consist of a damper, modulating damper actuator, flow ring, temperature sensor, and controller. Ramping of the supply fan is based on polling the zone VAV dampers to satisfy the critical zone. New DDC space temperature sensors shall be installed in room areas served by these MZ AHUs to allow for individual space scheduling ECM-02: Convert Dual-Duct AHU to VAV A Dual-Duct (DD) system is a dual path AHU that provides each zone a constant flow of supply air. The temperature of the supply air for an individual zone is controlled by mixing hot and cold airstreams at a terminal mixing damper at the space. The most common configuration is to have a heating coil (hot duct) and a cooling coil (cold duct) in parallel from the AHU. Each zone has a dedicated mixing box with a pair of dampers across the hot and cold ducts. Mixed air is delivered via a single duct to the diffusers for each space. A zone thermostat modulates the zone dampers to mix the hot and cold air streams in varying proportions. Often during cooling periods, the hot duct temperature is reset or inactive and acts as a bypass duct, equalizing with the mixed air temperature. As with most CAV systems, one of the primary inefficiencies is excess fan motor power consumption. This is especially true with units serving multiple zones. To satisfy space load, the AHU varies the temperature of air delivered to the space. Despite diversity in zone loads, the AHU provides design air Purdue University 3-27 Burns & McDonnell

60 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management flow at all times. In addition, thermal inefficiencies can occur. This is especially true if the coils for both ducts are active at the same time. Thermal losses due to air mixing will occur for each zone unless a zone requires supply air at either the hot duct setpoint or cold duct setpoint. This retrofit includes the installation of a VFD on the supply air fan and return air fans (if present). Each zone s mixing damper will become a two-position damper, at any given time open to either the hot duct or cold duct. These dampers shall be inspected for leakage and repaired. In most cases, the existing actuator can be left in service and used as 2-position. Each zone shall also receive a Variable Air Volume (VAV) box in the duct downstream of its hot/cold damper. This VAV box will consist of a damper, modulating damper actuator, flow ring, temperature sensor, and controller. Ramping of the supply fan is based on polling the zone VAV dampers to satisfy the critical zone. New DDC space temperature sensors shall be installed in classroom areas served by these MZ AHUs to allow for individual space scheduling ECM-03: Air-Side Economizer - AHU Modification Most non-research buildings on campus have AHUs that mix fresh air with return air from the spaces before conditioning and supplying back to the spaces served. Regardless of the AHU configuration, cooling coil temperature setpoints are maintained by using mechanical cooling. For many hours of the year, the outside air conditions are closer to the cooling setpoints of the AHU compared to the return air. During these times, if an AHU cannot receive 100% of its airflow from outside, cooling has to be provided by mechanical cooling. Enabling an AHU to open its fresh air dampers 100% and close return air dampers reduces the amount of cooling required from the campus CHW loop. When outside temperatures drop even further, the fresh air and return air dampers can modulate in sequence to maintain the cooling setpoint, thus taking advantage of free-cooling. This ECM includes the retrofit of AHUs with 100% outside air economizers. In some cases, this will require ductwork from fresh air louvers to the AHU capable of the unit s design air flow. In other cases, it requires only sequencing and new dampers and actuators. Special consideration should be given to the sequence and setpoints maintained by the economizer sequence to minimize the amount of mechanical cooling and heating needed. Purdue University 3-28 Burns & McDonnell

61 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management ECM-04: Air-Side Economizer - BAS Sequencing This ECM is similar to ECM-03 except that it applies to those AHUs that have economizer capability but are not programmed to do so. BAS programming is all that is necessary to return the units to the original economizer sequence of operation, assuming adequate fan capacity is available ECM-05: Air-Side Heat Recovery on Exhaust Air Many areas of the buildings surveyed exhaust air from the spaces such as restrooms, labs and general exhaust. In some cases, the exhaust air is isolated, and individual small fans are used to remove the air from the building. In other cases, much of the building exhaust air is ganged together into a common duct and relieved from the building via a single or multiple large fans. These fans often reside in the same mechanical rooms as the AHUs that serve the spaces. Adequate fresh air is brought in by the AHUs to make up the air exhausted from the building. This air has to be conditioned before delivered to the space. It takes a large amount of heating and cooling energy to condition fresh air. With a large amount of exhaust being necessary, there is no possibility of reducing the fresh air intake of the AHUs. The exhaust holds potential energy that could be used to pre-condition outside air before it is conditioned by the AHU and delivered to the spaces. This measure proposes to install a run-around glycol loop between an appropriate exhaust stream and the fresh air intake of one or multiple AHUs. Each application will require individual sizing and configuration of coils and pumps to recover the energy in the exhaust air stream and temper fresh air to the AHU(s). The existing fans will have to overcome additional static pressure through the heat recovery coil, so the systems will have to be re-balanced ECM-06: Eliminate Simultaneous Heating and Cooling During the building audits, the team discovered several AHUs with sequences that commanded the CHW valve to maintain a leaving water temperature or discharge air temperature at all times, while controlling the reheat valve/coil to maintain space temperature. It was understood that this was a common sequence for single-zone AHUs and some VAV AHUs with zone reheat. Temperature measurements in the AHUs were utilized to identify and quantify instances of this simultaneous heating and cooling. In Purdue s climate zone, there are some hours of the year where it is necessary to cool air down below 55⁰ F and reheat the air to maintain space humidity setpoints in ASHRAE s thermal comfort window (approximately 50%). However, a year-round sequence forcing the AHU to operate the CHW coil Purdue University 3-29 Burns & McDonnell

62 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management uncontrolled or at a constant discharge air temperature means the AHU will spend most of the hours of the year reheating the supply air to maintain space temperature setpoints. This results in wasted cooling and heating energy much of the time. The recommended solution for this issue is to install new or calibrate the existing space humidity sensors and include them in the control sequence for CHW coil discharge air temperature. The reheat valve and coil should be activated only during the times when space cooling load is minimal, but either reheating is required or humidity is high and dehumidification is needed. At this time, the cooling coil will cool the air below 55 F to remove moisture, and the reheat coil will heat the air back up to maintain space temperature. Note: Example energy models for a typical campus building in Indiana were created to show the results of the existing and recommended sequences described above. Allowing the cooling coil to cool below 55 F when needed, and using the reheat only when needed to maintain space temperature resulted in overall heating and cooling energy savings annually, but an increase in peak usage for CHW in the summer. This was due to the fact that the current sequence does not adequately dehumidify the air enough during these times. The reason for this is the low limit on discharge air temperature or the control of the leaving water temperature from the CHW coil to 63 F. Model results showed as high as a 0.5 ton per 1,000 cfm increase in peak CHW load ECM-07: Reduce ACH Rates in Unoccupied Lab Spaces Per conversation with Purdue staff, the majority of the lab spaces are designed and balanced to receive 6 Air Changes per Hour (ACH). This is to dilute and displace potentially hazardous chemicals that may be used in lab experiments. This policy matches common industry practice. While 6 ACH is the recommended occupied rate, industry standards allow the ACH rate to be reduced when the labs are unoccupied. The labs currently do not have the capability to reset the ACH rates. This ECM would utilize an occupancy sensor installed in a lab room and reprogramming of the controls to reduce the airflow during unoccupied times. When the space is unoccupied, the airflow would be reduced to four air changes per hour. This would dramatically reduce the fan power, cooling, and heating demands during unoccupied times (Approximately 33% reduction). Air change rates during occupied times would be unchanged. Purdue University 3-30 Burns & McDonnell

63 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management ECM-08: Convert 100% Fresh Air AHU to Mixed Air Some areas are currently served by single-pass 100% outside air AHUs even though 100% OA is not required for the space functions. These spaces could be adequately served by a re-circulating system that re-circulates air from Class I spaces to Class I or Class II spaces. This was found in multiple buildings on campus. (Air should not be re-circulated from a Class II space.) This ECM would reroute the existing exhausts or take advantage of already in place ductwork from these spaces back to the existing AHU intake. Return and outside air dampers shall be installed to control the OA mixture of delivered air, as well as provide economizing times during cooler OA conditions. It is necessary in most cases to re-position the existing exhaust/relief fan and operate it as a traditional relief fan delivering air to the AHU and out of the building. This will dramatically reduce the cooling and heating demand for these areas ECM-09: New Space Temperature Sensors w/scheduling and Occupancy Currently, the Building Automation System (BAS) in each building is centralized around large equipment or systems like AHUs and pumps. There are sensors, valves, VFDs, relays, and other control points that feed back into one of the two campus-wide Automation Systems. There are very few control points beyond the system level as described above. A majority of the space controls consist of pneumatic thermostats that directly control their space-level HVAC unit, whether that be fin-tube radiation, a VAV box with reheat, or a DD or MZ mixing damper. There is no feedback from the space level to the BAS, and thus no ability to monitor or program temperature setpoints for the space. In some cases, there is a single night setback thermostat in a sample space served by an AHU. This stat was originally intended to monitor a sample space at night and cycle the AHU off to maintain this space setpoint. However, it was observed that most of these were no longer correctly controlling AHUs at night, either because of local overrides or unknown sequence modification. In a classroom and office environment, space use typically has a predictable pattern either based on office hours or class schedules. Currently, AHUs operate no differently during unoccupied hours than during occupied hours. This results in wasted fan energy, cooling energy, and reheat energy. This ECM provides for additional controls at the space level to sense and respond to varying space requirements. In office areas, new DDC space temperature sensors will be installed and programmed via the BAS for occupied and unoccupied temperature and ventilation setpoints. In classrooms, new DDC space temperature sensors will be paired with dual-technology occupancy sensors and CO 2 sensors. The Purdue University 3-31 Burns & McDonnell

64 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management combination of these sensors in the classrooms allows for two levels of control. First, class schedules can be migrated from the existing campus database and programmed into the BAS to maintain space temperatures and ventilation at appropriate occupied setpoints during classes. Secondly, occupancy sensors and CO 2 sensors provide feedback to the BAS on actual occupancy in the space, which in turn allows the AHU and terminal unit serving that space to adjust temperature and ventilation from the programmed schedule. This tightly controlled space optimization eliminates wasted energy usage during unoccupied times and maintains appropriate conditions when the space is occupied ECM-10: Low Flow Water Fixtures The majority of the plumbing fixtures in each of the campus buildings have not been retrofitted with new low-flow fixtures. Faucets are not equipped with aerators. Toilets and urinals seem to be original in some cases or simply antiquated. Water used in these older fixtures represents a significant portion of the total water demand for each building. Due to the high volume of use in a campus setting, millions of excess gallons a year are used to do the same job that a quarter or half of the water would do. This ECM includes the replacement of all standard fixtures with new low-flow fixtures. The low-flow fixtures will include ultra low flow (ULF) 1.28 gallon per flush toilets and flush valves, gallon per flush urinals and flush valves, 1.0 gallon per minute shower heads, 0.5 gallon per minute aerators in bathroom lavatories, and others as applicable to specific plumbing situations. The program will include installation, tile work, related repairs, and any other work needed to complete the low flow fixture retrofit ECM-11: Water-Side Economizer - Plate HX at Plant Some AHUs are not able to take advantage of air-side economizing for several reasons. For instance, AHU-13 in Hovde Hall is in the core of the building and has no path for a full-size fresh air duct or relief air duct to the outside wall. This results in CHW usage year-round to cool the interior spaces. Other AHUs are not able to economize because of space constraints like particulate or humidity requirements. This ECM has not been considered in the specific building analysis, but could offer winter time savings if investigated at the central chilled water plant. The year-round use of CHW from the plant means that chillers have to run along with cooling towers, pumps, and other associated equipment at the plant, even though outside temperatures are well below the temperature of the chilled water delivered to the buildings. Purdue University 3-32 Burns & McDonnell

65 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management The installation of a water-side economizer allows for the production of free chilled water when the outside air temperature is sufficiently low. Chilled water is created using condenser water directly in a plate and frame heat exchanger (HX) instead of using the plant chillers. The system would utilize control valves and the BAS to switch operation from cooling via the chiller to HX and back. Once the outside air temperature has gotten sufficiently low, the chiller would be shut down and the cooling water and CHW flow will be diverted from the chiller to the HX. Note: The installation and use of any free-cooling apparatus at the central CHW plant should be coordinated with projected campus off-peak load and asset dispatching. This analysis for the building need only takes into account the savings achievable by the offset of mechanical cooling ECM-12: Insulate Steam Condensate Piping Low-pressure steam heat is used in all campus buildings audited in some form or fashion. The steam condensate returns through piping back to receiver tanks in each building, where it is pumped back to the plant typically by electric centrifugal pumps. Much of this condensate piping was observed to have no insulation, either by design or because it was removed. Conversations with IAQTs revealed that it is standard practice to not only leave condensate piping un-insulated, but try to further cool the condensate before it enters the receiver tanks. One building audited has installed fin tube radiation in mechanical rooms to reject condensate heat. It seems that University staff has experienced chronic issues with failed seals from condensate pumps getting too hot. Condensate piping and other steam components are at a consistent operating temperature of ⁰ F year-round. At this temperature, heat loss from the un-insulated pipe, tank, or other component is significant and constant. It is also a significant safety issue when it occurs in occupied rooms or hallways. Mechanical rooms often contain the most un-insulated condensate piping due to the point of use. In many cases, there was significant duct leakage or even cold air taps into the duct to cool the mechanical room. For instance, approximately 800 cfm of 55 F air was measured through a dedicated VAV box and register into the basement mechanical room of the Mechanical Engineering Building to attempt to cool a room with a significant amount of un-insulated steam piping and tanks. This cold air was supplied by a 100% outside air AHU. In the summer, the benefit of pipe insulation is two-fold. The heat is not radiated and can be returned back to the plant, and the cold air duct leakage is no longer needed to cool the room. Ducts can be sealed and taps/diffusers can shut off to provide more cooling to the occupied spaces. Purdue University 3-33 Burns & McDonnell

66 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management This ECM recommends the insulation of all condensate piping in buildings where accessible, along with any tanks and components not often in need of adjustment/maintenance/repair. Along with this insulation effort, investigation should be made into historical problems with the condensate pump systems to prevent pre-mature wear and/or failure ECM-13: Replace IGVs with Fan VFDs There are several existing VAV AHUs that use Inlet Guide Vanes (IGV) for volumetric flow control. With this type of control the fan speed remains constant and flow is modulated by restricting the fan inlet area with the vanes. The modulation of the IGVs changes the fan curve slightly so it operates at a constant speed with less horsepower. Most of the IGVs noted are original to the equipment. Although all were found to be generally operable, many would not fully open or would stick at a certain position until stroked dramatically by the control signal. This type of mechanical flow control is less efficient than using VFDs to modulate the speed of the fan. Savings over the IGV control are realized in different magnitudes depending on the type of fan blades. All of the fan wheels with IGVs found used forward curved blades The way that the IGVs operated on the observed fans caused an unnecessary restriction of flow (addition of static pressure), which draws more power from the motor for a similar flow rate. This modification includes the removal and disposal of existing IGVs and the installation of VFDs to control fan speed. The existing motors will be replaced with premium efficiency motors. The fan speed will be modulated to maintain a duct static pressure, similar to the existing control method. A VFD can also serve as a soft start for motors at the beginning of an operating schedule, increasing motor life and preventing power spikes during startup ECM-14: Disable Steam Humidifiers in Off-Season Low-pressure steam is used in most campus buildings that were audited for humidification of supply air to the space. Although the audits were performed during the cooling season, approximately half of the humidifiers were maintaining hot cylinders ready to humidify. These humidifiers are designed with bypass steam to maintain hot cylinders so dry steam can instantly be injected into the airstreams. The nature of these humidifiers delivers some steam even when no humidification is needed. This translates to significant heat loss. For the humidifiers energized during the cooling season, this creates an unnecessary cooling load that adds to the energy consumed by the building. Purdue University 3-34 Burns & McDonnell

67 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management This ECM provides for the manual isolation of all humidifiers during the shoulder and summer months. Careful consideration should be given to piping configurations if drip-leg steam traps are not installed to properly drain condensate upstream of the isolated humidifier to prevent water hammer. Isolation of these units will result in steam and CHW usage savings most of the year and a reduction of peak CHW load during the summer ECM-15: Change Air Filters Many of the AHUs observed, had air filters that were dirty and in need of replacement. Air filters consist of box pleated filters (of varying efficiencies), roller filters, and HEPA filters in some lab applications. In some cases, filters were found to have blown out of the rack due to static pressure build-up caused by extreme loading of the filter. Although air filters are a relatively inexpensive component, lack of proper maintenance will increase energy consumption and degrade system performance. AHUs, especially those that vary air volume based on space loads, will compensate for dirty filters by increasing fan speed or IGV position, maintaining airflow at the expense of added horsepower. This ECM provides for the replacement of dirty filters and sometimes the removal and replacement of old roller filters in disrepair. It is also recommended that a campus wide filter maintenance program be implemented and championed to record and assure constant filter maintenance. Clean filters can reduce fan energy consumption by as much as 5% ECM-16: Static Pressure Reset on VAV AHUs and Exhaust Systems VAV AHUs were observed to be controlling to a constant duct static pressure setpoint of 2.0 inches W.C. or higher to supply air to all the VAV boxes they serve. This setpoint is usually established to meet the maximum air flow requirement of the system. Fan energy is wasted in VAV AHUs if they are set to maintain a fixed setpoint at all times, because the duct is over-pressurized for much of the system operation. As VAV boxes close off due to lower space requirements, duct static pressure increases. At lower operating conditions, less duct static pressure is needed to supply air to the most remote zones. If the static pressure setpoint remains constant, the fans are not modulated to maintain the lowest possible static pressure setpoint and energy will be wasted. Purdue University 3-35 Burns & McDonnell

68 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management This measure consists of programming to reset the static pressure setpoint on all VAV AHUs. This measure will reduce the wasted fan energy of VAV AHUs maintaining a fixed setpoint at all times. Note: The exhaust fans recommended for static pressure reset are in Hansen and Lynn research buildings. MHER-34 in Lynn was measured to be pulling close to 5 inches static pressure at the inlet even though it is rated for 3 inches and programmed to maintain 2.25 inches. An immediate fix for this would be to correct the pneumatic control tubing on the signal transmitter, causing the correct setpoint to be relayed to the fan ECM-17: Optimize DAT Temp/RH from Make-Up Air AHUs The two D/X AHUs on the roof of McCutcheon Residence Hall are 100% fresh air units delivering conditioned air to the corridors of both wings of the building. In addition to using the D/X for cooling, some of the hot refrigerant gas is used to reheat the supply air. This provides an economical form of dehumidification to the fresh air delivered to the resident rooms. However, temperature logs and BAS trends confirmed that the hot gas reheat is operating unchecked or at an inappropriate space humidity setpoint. Since the installation and commissioning of the two AHUs, University staff have had repeated problems with the units not functioning as they were designed. The BAS does some monitoring of the units, but has no control over the D/X system. This lack of control results in inadequate temperature and humidity control due to over-dehumidification and slight over cooling during unoccupied times. This ECM provides for the reprogramming of occupied and unoccupied temperature and humidity setpoints maintained by these two AHUs. This will require minor programming and possibly further integration with the AHUs. The AHUs should be re-commissioned during this work to verify proper D/X hot gas reheat operation and dehumidification control ECM-18: Schedule Equipment Off (Computers) During the times of the audits, some unoccupied computer labs were observed to have computers running in screen saver mode. Since campus computers have overall inconsistent use, there are many hours of the year where they could be shut off to save electricity. Computers left in screen saver mode use similar amounts of electricity to when they are on and being used. Purdue University 3-36 Burns & McDonnell

69 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management This ECM recommends implementing a campus-wide computer maintenance program that concentrates first on larger computer labs and uses the built-in software to program a sleep-mode after 20 minutes of no use. Sleep-mode uses approximately 5-10% of the electricity compared to the on-mode. This can translate to tens of thousands of kwh annually saved by simple programming. 3.9 ECM DESCRIPTIONS RECOMMENDED, NOT EVALUATED The following describes ECMs more unique to specific buildings and those found randomly throughout the survey. It should be noted that the costs and savings for these items were not calculated due to their infrequent occurrence throughout campus ECM-19: Repair/Replace Leaking CHW Valves Through temperature measurements at AHUs and chilled water piping was utilized to identify several CHW valves that were leaking by. In all cases, the cause was that the valves did not receive the correct control air pressure to close tightly, or the valve seal was bad. This can cause a lack of CHW control at a coil, resulting in simultaneous heating and cooling. In addition, new technology exists that allows the control valve to operate independent of the pressure in the chilled water system. This can be compared to the difference between as simple damper and a VAV box. Purdue currently recommends installing these valves in new buildings. recommends a thorough commissioning of CHW control valves and creation of a control valve inventory and preventative maintenance program. This should be followed with a replacement plan to replace all chilled water valves with pressure independent control valves ECM-20: Replace Modified Three-Way CHW Valves with Two-Way A few three-way CHW control valves had been modified to act as a two-way valve. This was most likely done when a VFD was installed on the pump, and a variable volume CHW loop was established. However, the way the valves were converted was to shut the isolation valve on the bypass leg. Because three-way valves are not designed to close off against water pressure, relying on the three-way modified valve to modulate flow from 100% to 0% flow is unrealistic. Most valves are shown to operate in the bottom third of their open percentage, and this is where modified three-way valves perform poorly, due to the increased pressure drop across the valve. In addition, new technology exists that allows the control valve to operate independent of the pressure in the chilled water system. This can be compared to the difference between as simple damper and a VAV box. Purdue currently recommends installing these valves in new buildings. It is recommended these modified valves be replaced with two-way pressure independent control valves. Purdue University 3-37 Burns & McDonnell

70 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management ECM-21: Repair Duct Leakage Discharge air ducts from AHUs are generally in good repair, but several holes/rips/seams were found to be leaking air into the mechanical rooms. Although this can sometimes be desirable for building operators and maintenance personnel due to the cooling effect, it compromises the primary purpose of the AHU: to condition the occupied spaces. This ECM recommends the use of duct sealant and metal patching to repair leaking ducts. In many instances, this measure will compliment the insulation of condensate piping. Insulating the radiant sources in the mechanical rooms will minimize the need for cooling ECM-22: Replace Faulty Temperature Sensor A few of the AHUs audited had faulty temperature sensors, usually of the averaging type. These sensors are used to average the air temperature across a hot or cold coil. If not calibrated properly, these sensors will provide erroneous readings. They can also drift out of calibration. Faulty sensors can result in over cooling or heating of an airstream, which in turn causes simultaneous heating and cooling. This ECM recommends the commissioning/calibration of all temperature sensors used for controlling heating and cooling in an AHU. This can be a simple as comparing the BAS reading with the reading of a calibrated thermometer. This calibration process is recommended to be part of a recurring preventative maintenance program ECM-23: Optimize Heat Recovery Water Loop Operation In the research buildings where heat recovery loops are common on 100% fresh air AHUs, several instances of improper loop operation were observed. While heat recovery loops are very beneficial during more extreme outdoor air temperatures, there is a range of temperatures where the pump energy usage of the loop outweighs the thermal benefit. In addition, there is a small temperature band where running a heat recovery loop can actually increase the heating and cooling energy usage in an AHU. This ECM recommends the creation of a common programming sequence to be implemented at all general heat recovery loops, turning the pump off when it is not economical to operate ECM-24: Elevator Motor Replacement Even though attempts to confirm with the local Dover Elevator representative were unsuccessful, it is believed that the elevator motor and equipment powering the elevators in McCutcheon Residence Hall are high energy consumers. These old elevator motors utilize an AC-to-DC generator and DC motor to drive the cars. This is an antiquated way of varying speeds and soft-starting motors, and results in high energy Purdue University 3-38 Burns & McDonnell

71 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management use compared to newer elevator motor technology. In addition, the existing motors and equipment are well past their useful service life and should be considered for replacement. This ECM recommends the inspection and replacement of the DC elevator equipment on both wings of McCutcheon Hall ECM-25: CHW Btu-Meter Commissioning Chilled water energy meters have been recently installed at each existing building. Many existing meters have strap-on ultrasonic transducers, which do not physically penetrate the pipe. This measured flow is used in conjunction with strap-on temperature sensors on the supply and return pipes to calculate an instantaneous energy rate as well as aggregate the chilled water energy usage of the building. Although ultrasonic flow measurement can be highly accurate for short term measurements, it is not recommended for the continuous long term service as applied here. Low flow conditions and change in fluid and ambient temperature degrade the accuracy, and the substance used to couple the transducer with the pipe degrades and evaporates over time, resulting in inaccurate readings. In addition, the strap-on temperature sensors used for supply and return temperature measurement are installed on pipe where insulation was removed and not re-installed. Ambient temperature significantly affects sensor readings when no insulation surrounds the sensor. The inaccuracy of the temperature sensors was verified by looking at the local flow meter modules and comparing to measured temperatures. Temperature readings averaged 4-8 F higher than the actual temperatures. It is recommended that immersion temperature sensors as well as immersion flow meters be used for chilled water. (This method of installation was observed in some locations already.) Electromagnetic or venturi flow meters are standard industry practice for chilled water applications and would be appropriate for these buildings. Turbine meters can also be utilized; however they have a higher pressure drop. Purdue is currently installing in-line electromagnetic meters in existing buildings and all new capital projects ECM-26: Isolate Steam Systems in Off-Season Currently, the steam system is active throughout the campus year round to be used for reheating, desiccant activation, domestic water heating, and other purposes. Although many of these needs are legitimate, the steam systems in most buildings are piped to allow the isolation of a single system while other building steam is active. For instance, some buildings with steam or hot water radiation were found with these steam systems live during cooling seasons. There is no time during the summer when perimeter heating is needed. This ECM recommends the careful inspection of steam systems in each building to determine what systems can be manually isolated during shoulder and summer seasons, eliminating the continuous steam losses through radiation and drip leg steam traps. Purdue University 3-39 Burns & McDonnell

72 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management ECM-27: Eliminate Vacuum and Compressed Air Leaks All eight of the buildings audited use compressed air for pneumatic controls at some level. Pneumatic piping, tubing, and end-devices are common for space-level controls as well as AHU damper and valve actuation. Lynn and Hansen research buildings have additional compressed air and vacuum systems for laboratory equipment and point use. In both compressed air and vacuum systems, a constant pressure is maintained on the system by compressors and vacuum pumps. Since the demand on these systems is variable, the compressors and pumps are designed to cycle on and off. During the building audits, some of these compressors were observed cycling at a high rate, indicating either a high instantaneous use or leaks in the system. This ECM recommends a dead-test of the compressed air and vacuum systems in these buildings. This consists of isolating or de-activating all loads on the system and observing the cycle rate of the compressor and vacuum equipment. This test will identify which systems should be inspected for leaks and repaired ECM-28: Residence Hall FCU Control with Smart-Phone Operation Every room in McCutcheon Residence Hall is conditioned individually by a suspended Fan Coil Unit (FCU) supplied with chilled water from the building s central loop. Heating is provided via perimeter radiation. Every FCU is shut off in the summer if the room is unoccupied, but runs continually during the school season using a room thermostat to open or close the CHW valve and enable cooling. The fan runs at medium speed constantly. It is common for most students to leave their thermostat at a constant temperature throughout the day, using much more cooling/heating energy than necessary. This measure proposes to link the FCUs to the web-based BAS to allow control from the BAS. The existing room controllers will be replaced with new smart thermostats to allow for both local control in their rooms as well as remote-control via the internet. Because the control system is web-based, the students would be able to control and schedule their individual FCUs with their smart-phones or from any internet-capable device. By providing this capability, students will be able to customize their own room conditioning and save energy by not conditioning their spaces during vacant times. By providing each resident their own secure login and password to the BAS, they could access only their FCU. However, careful consideration should be given to password protection and other security issues related to this measure. Purdue University 3-40 Burns & McDonnell

73 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management To further energy savings with this measure, it is recommended that residence hall coordinators develop initiatives such as a competition between residents to use the least amount of energy through the year. This can easily be monitored through trending in the BAS ECM-29: Eliminate CHWR Temperature Control In general, all of the buildings audited have a common CHW sequence that attempts to limit return water back to plant to a temperature not less than 63 F. This sequence exists at AHU CHW coils as well as some building-level recirculation valves. The following is an interpretation of the historical account provided by University staff leading to this sequence. Late 1960 s CHW bypasses existed in the buildings, in the form of AHU three-way valves, building level recirculation valves, and building pumps s Building bypasses were abandoned in favor of one-pass CHW through a building. To account for coils not designed for high ΔT s, sequences were written to limit chilled water return temperatures to 63 F s Reports of humidity concerns increased across campus buildings. Sequences were altered to control chilled water valves on space humidity in addition to the 63 F return water temperature. The audit and programming code interpretation showed a variety of sequences across the eight buildings surveyed. A majority of CHW coil sequences include control of return water temperature as a base with an additional control to discharge air temperature or return air humidity. The hours spent controlling to return water temperature versus controlling to humidity was not quantified. This is highly dependent on the coincidence of space loads and outside air conditions. It is apparent that most AHU sequences have evolved and been tailored in response to their individual space needs and historical complaints. Conversations with building occupants and Indoor Air Quality Technicians (IAQTs) revealed a variety of spaces that do not maintain thermal comfort standards, especially noticed during curtailment periods in the summer. These spaces were not limited to general function, but included some laboratory and research areas of Lynn and Hansen. CHW ΔT syndrome is a common problem on college campuses, due to the variety of coils, valves, pumping and control schemes. A decreased ΔT results in increased pumping energy and an effective decrease in distribution system capacity required to deliver the tons of CHW required. There are several standard approaches to masking this problem, but all of these result in increased energy usage, thermal Purdue University 3-41 Burns & McDonnell

74 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management comfort issues, or both. The following operational changes and solutions to each level of a campus chilled water system are recommended: AHU Coils Start with the coils. These should be the first level of analysis and improvement across campus to alleviate CHW ΔT issues. If coils operate at design ΔT or better, all bandaids such as CHW return water control should be eliminated. Coils that do not consistently achieve design ΔT should be cleaned and commissioned thoroughly. Any three-way control valves and non-pressure independent control valves should be replaced with two-way pressure independent control valves, eliminating the possibility that cold supply water bypasses into the return stream. Building-Campus Interface Once coils and valves are set up to achieve a good ΔT, the building interface to the campus CHW system should be addressed. The goal of this work is to eliminate the recirculation that occurs in the building, tempering cold CHW from the campus supply with return water from the building. Any re-circulation back into the supply to the building negates some of the work done by the chiller plant to produce cold water. The added effect is the loss of humidity and sometimes temperature control at the AHUs, due to the warmer CHW supply delivered to the coils. Using a building recirculation valve to control the leaving CHW back to the campus loop should be eliminated. If pumps exist in the buildings, they should only be used as booster pumps to increase pressure at the building when campus pressure does not suffice. All pumps should be variable speed. If coils are fixed or replaced, discharge air temperature and humidity can be maintained at all times, resulting in thermal comfort in the spaces. This should be a priority. Next, sequences dictating 63 F return water temperature, both at the coils and building re-circulation valve, should be eliminated. Due to the fact that many spaces are currently experiencing thermal comfort deficiencies, fixing these CHW ΔT problems might result in increased energy consumption. However, the magnitude of this is unknown and unpredictable and might be counterbalanced by the improved performance of the system when other ECMs are implemented. A staged approach across campus is recommended that carefully implements these strategies while monitoring the effect on the campus chilled water system. The following plots show trend data gathered from data loggers and BAS monitoring. Each plot is named by the ECM it represents. Purdue University 3-42 Burns & McDonnell

75 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management 3.10 TREND DATA ANALYSIS The following plots show trend data gathered from data loggers and BAS monitoring. Each plot is named by the ECM it represents. Figure 3-3: [ECM-06] Eliminate Simultaneous Heating and Cooling 110% 100% YG AHU % 70 80% 70% 60% REHEAT COIL LEAVING AIR TEMP CONTROLLED INDEPENDENTLY. RESULTS IN SIMULTANEOUS HEATING AND COOLING SF Speed 50% 40% CHWV % CC Temp DA Static COOLING COIL LEAVING AIR TEMP REMAINS CONSTANT % PC Temp 20% 10% CHWR Temp Discharge Temp % 0 Purdue University 3-43 Burns & McDonnell

76 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Figure 3-4: [ECM-29] Eliminate CHWR Temperature Control EE CHW Pumps BUILDING RECIRCULATION PREVENTS COLD WATER FROM RETURNING TO THE CAMPUS LOOP, OPENING BLDG RE CIRCULATION VALVE. CHW SUPPLY TEMP TO BLDG INCREASES BECAUSE OF BLDG CHW RE CIRCULATION. AHUS RECEIVE 57 F CHW, AND COIL DELTA T REDUCES SIGNIFICANTLY CHWR to Plant CHWS to Bldg CHW Delta T CHW Pump DP CHW Pump On/Off Purdue University 3-44 Burns & McDonnell

77 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management Figure 3-5: [ECM-09] New Space Temperature Sensors w/scheduling and Occupancy 1 EE Auditorium AHU AUDITORIUMSPENDS MOST SUMMER DAYS AND NIGHTS UNOCCUPIED, BUT AHU CURRENTLY RUNS MOST OF THE TIME, VENTILATES THE SPACE, AND COOLS TO 72 F Fan Status Purdue University 3-45 Burns & McDonnell

78 Comprehensive Energy Master Plan FINAL DRAFT 3.0 Demand Side Management 3.11 IMPLEMENTATION PLAN The results of the analysis of selected Purdue campus buildings and the extrapolation of those results across the campus building portfolio has clearly demonstrated that there is a strong business case for implementing a comprehensive energy reduction program. The effective planning and implementation is critical to realizing the potential benefits of this opportunity. The approach of selecting Performance Contractors to identify energy conservation measures with a short payback will not provide Purdue with the best investment results for this initiative. Investments that reduce building energy consumption also reduce both operating and capital costs. The operating cost reductions are obvious, less coal, natural gas and electricity to purchase and less pumping energy to distribute the utilities to the campus buildings. The other benefit of reduced building consumption is the impact on future capital expenditures for utility production and distribution equipment required to accommodate planned campus expansion. Existing system capacity becomes available to support planned campus expansion. Therefore developing the business case for these interrelated investments and operating expenses requires that they be accounted for in the analysis. This requires modeling of the impact of a portfolio of demand side energy improvements on the production and distribution systems and future energy purchases to develop life cycle cost comparisons of several comprehensive solution sets. The depth of retrofit for the campus buildings should be determined by the economic performance of the options considered. The investment criteria applied to the demand side investment should be similar to those applied to the production and distribution systems. Since the demand side projects are essentially funded from the savings of ongoing operating expenses, the more rapidly they can be accomplished the sooner the benefits will begin to accrue for both operating and capital savings. In order to implement this program in a timely manner and minimize the interference with ongoing campus educational and research activities, a comprehensive program management approach will be required. The coordinated resources of multiple consultants and contractors will be required for effective delivery of the desired results. Purdue s in-house project management resources will probably need to be supplemented by a Program Management consultant to handle the scale of the multi-year initiative. * * * * * Purdue University 3-46 Burns & McDonnell

79 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review 4.0 CONTROL SYSTEM REVIEW A review of the installed Building Automation and Control Systems was performed that concentrated on the installed technology, current control strategies, algorithms and sequences of operation to identify existing deficiencies. This effort was focused on the buildings surveyed as part of the Demand Side Management task. The focus of the Control System Review was to identify methods for standardization of practices, procedures, and recommendations to improve communication between field staff and the Building Systems Group. 4.1 CURRENT BUILDING AUTOMATION SYSTEMS CONFIGURATION Purdue University currently utilizes Automated Logic and Siemens for the University s HVAC building control systems. Dual systems allow Purdue to have a choice on which control system and components will be installed. These decisions are based on application, options, pricing, and services provided. The control systems are similar in the fact that they have zone to user interface level controls and have the capability to meet most sequence of operations through custom programming. Both Siemens and ALC can utilize a BACnet MS/TP communication protocol which is beneficial in communicating to factory equipment controls. They have different programming and setup applications and use different field devices such as space and pressure sensors. The controls systems are monitored by the Purdue University Building Systems Group who handles trouble calls from the Purdue University IAQ Teams. Information on the existing HVAC and controls systems throughout campus are archived with the Building Systems Group including, one-line control diagrams, building layouts depicting what areas equipment serves, point trending, and any retrocommissioning or energy studies. 4.2 USER INTERFACE The Purdue University Building Systems Group is maintained by three console technicians with dual work stations that provide support to the field technicians regarding the building automation systems. Each workstation provides a user interface to both ALC and Siemens control systems. The ALC system communicates to the workstations through the Purdue Web Network. This allows the user to connect to any port on the Purdue network to access ALC information throughout the campus. The Siemens system Purdue University 4-1 Burns & McDonnell

80 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review is communicating on a closed loop which is only accessible from the console front end workstations or by plugging directly into Siemens area controllers. Siemens has the technology to provide a web network based level of access to the system, and plans to implement this strategy at Purdue in the future. The ALC system user interface provides the user with live data through the ladder-logic programming tool. Users of the ALC system must decipher the programming to identify exactly how the equipment is operating. (See example below) Figure 4-1: Example of Ladder-Logic Programming On new projects, when control contractors are involved, graphical user interfaces (GUI) are created which includes thermo-graphic floor plan displays that indicate if a room is above or below setpoint with a color indicator. Also, displayed are pictures of the equipment being controlled, locations of control sensors, and current setpoints. (See examples below) Purdue University 4-2 Burns & McDonnell

81 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review Figure 4-2: Example of a Thermo-Graphic Floor Plan Control Interface Figure 4-3: Example of an Air Handling Unit Control Interface Purdue University 4-3 Burns & McDonnell

82 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review The Siemens system user interface provides the user with live data and low-level programming code. Users must decipher the code and bring up a live screen of data to troubleshoot and identify system issues. (See Figure 4-4 below) Figure 4-4: Control System Programming Code On new projects where the design, programming and installation is outsourced to a separate contractor, graphical interfaces have been created. In order to create graphics on existing ALC controls, the ALC contractor would require the air-handling unit (AHU) controls diagram drawing in Microsoft Visio format. Currently, the existing control diagrams are in Bentley Micro-Station format and would require a software upgrade to Microsoft Visio Tech Edition which converts dwg, dxf, and dgn drawings to Visio formatting. In order to create graphics for existing systems utilizing Siemens controls, it would require considerable time, funding, and resources because of the large amount of controls installed on campus. 4.3 DESIGN REVIEWS AND SEQUENCE STANDARDS ON NEW PROJECTS Purdue University is currently implementing standard sequences of operation, on all new construction projects, during the Building Systems Group s design review of the project. The reviews consist of verifying the proposed control system and strategy meets Purdue University s requirements and Purdue University 4-4 Burns & McDonnell

83 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review standards. Below are the standard basic sequences of operation requirements as provided by Purdue University Staff: Safety (mixed-air units): If the mixed-air temperature (or preheat leaving temperature) is less than 45 F, close the outside and relief dampers and open the return-air dampers. The chilled water valve shall modulate to full open. If physical low-limit stat (38 F) trips, the fan shall stop and alarm issued. Safety (dedicated outside-air units): If preheat leaving temperature is less than 45 F, open the preheat valve and chilled water valve. If physical low-limit stat (38 F) trips, the fan shall stop and alarm issued. Economizer Cycle: Activate cycle when outside air temperature is less than 75 F and the dew point is below 55 F. The economizer shall control to mixed-air temperature. During this time the chilled water return temperature (63 F) program shall be disabled and unit shall control to cold deck leaving-air temperature. Cold Deck/Chilled Water Control: Chilled water shall modulate to meet cold-deck setpoint (typically 55 F). If the chilled water leaving temperature is less than 63 F, this shall override the discharge-air temperature (DAT) setpoint control to ensure that the leaving water temperature does not go below 63 F. If the return humidity rises to 50%RH, then the return water low-limit reset shall utilize the following reset schedule: Table 4-1: Chilled Water Return Reset Schedule Return Air Humidity CHW Low Limit Setpoint 0-50% 63 F % 58 F Cold-Deck/Chilled Water Control (dedicated outside air unit): Same sequence as indicated above (4), except if the outside-air temperature is less than or equal to 65 F, then the 63 F return water low-limit is disabled and the unit shall control to straight cold-deck leaving temperature. Chilled Water Pumping Systems: Chilled water pumps shall start if the building chilled water differential pressure drops below setpoint. Enthalpy/Economizer Control: Economizer cooling is enabled/disabled based on the return-air and outside-air enthalpy differential switchover point with a 1.5 BTU/lb dead-band. When the outside-air enthalpy is no more than 1.0 BTU/lb below the return-air enthalpy, economizer cooling is disabled. When the outside-air enthalpy is below return enthalpy by at least 2.5 BTU/lb, economizer cooling is enabled. When economizer cooling is enabled the maximum outdoor-air, return-air, and relief dampers shall modulate together to maintain a mixed-air setpoint of 53 F. When economizer cooling is disabled, the maximum outside-air and relief Purdue University 4-5 Burns & McDonnell

84 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review dampers are fully closed; the return-air damper is positioned for minimum outside-air ventilation. When the outside-air is less than or equal to 65 F, the 63 F return water low-limit is disabled and the unit will control to a straight cold deck leaving air temperature. 4.4 TROUBLE CALL PROCEDURE The current trouble call procedure is as follows: 1. Thermal or system malfunction complaint received by IAQ technician from occupant/user. 2. IAQ technician attempts to troubleshoot issue on-site. 3. If the issue found is a mechanical/electrical failure of specific equipment, the technician will make the necessary adjustments to the system and submit a request for a replacement part (if not in inventory) and wait to make repairs. When the issue is not apparent, the IAQ technician may choose to contact the Building Systems Group for more information on the operation of the system(s). 4. The Building Systems Group receives a call and brings up specific system programming and live data. The Building Systems Group works with the IAQ technician to identify the issue. 5. After the issue is found, repairs are made, or programming adjusted to correct the sequence of operation. At times, the IAQ technicians may choose to make adjustments to improve occupant thermal comfort without consulting with the Building Systems Group (ie- Console Group). If the Building Systems Group is consulted, they may make programming or sequence changes to improve the occupant s thermal comfort until permanent repairs are made. It is recommended that changes made to the system, whether by the IAQ technician or the Building Systems Group are documented for future reference. When an issue surfaces with a system it is not always clear on what changes have been made to the system. 4.5 IMPROVING TROUBLESHOOTING EFFORT Providing more information to the field technicians will improve the details of the thermal comfort issues relayed back to the Building Systems Group. Giving the field technicians access to user friendly graphics and detailed sequence of operations will improve their understanding of how the systems work and should improve the troubleshooting and preventative maintenance effort. Currently the technicians have access to a laptop computer with the software required to access the control systems, a recently instituted apprentice program will allow proper training to effectively utilize the software to troubleshoot the systems. The benefit of this program will be greatly enhanced with a user friendly, graphics oriented interface. It was also noted that some technicians may not favor the effort required to access system data Purdue University 4-6 Burns & McDonnell

85 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review and will just call the Building Systems Group to troubleshoot the system. Although the Building Systems Group is well trained and efficient at troubleshooting, there is such a vast array of system information from the numerous buildings that providing more user friendly information would still improve the Building System Group s reaction time to resolve the issue. This should also free up time for the Building Systems Group to focus on small projects and updating existing control systems. It is recommended that training and workshops be provided by the Building Systems Group to the IAQ techs on how to operate building automation software, maintenance procedures for replacing components of the control system, and effective troubleshooting techniques. Cross-training of staff and introduction of new staff to the operations and programming efforts performed by the Building Systems Group is critical. The University s entire controls programming and operations knowledge base rests with just a few senior staff members (Console Group) who have responsibilities as shown on the following Figure. The Console Group is largely responsible for controls system programming and remote troubleshooting when called upon by building level IAQ techs. These two groups currently operate in separate management groups which limits interaction and the opportunity for IAQ techs to receive training in the proper diagnosis of building control issues. The IAQ techs rely on the Console Group for much of the control system diagnosis and trouble resolution. Figure 4-5: Existing Controls System Responsibilities Purdue University 4-7 Burns & McDonnell

86 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review Should the two teams become integrated into a single management group with the need to communicate regularly regarding training and building issues, the proposed responsibilities in the following figure could be realized. The benefit to Purdue is a single organization that is tasked with building operations and ongoing maintenance issues from the perspective of the controls system. Figure 4-6: Proposed Control System Responsibilities 4.6 PREVENTATIVE MAINTENANCE There is currently a group that performs the preventative maintenance duties for the entire Purdue University campus. The duties include filter changes, fan belt inspections, lubricating fan and pump motors, and identifying failed steam traps. It is our understanding that their responsibilities do not include cleaning of the ductwork, dampers, or coils, evaluating the HVAC controls sensor and operation, or verifying sequence of operations of the unit. It was not determined on how frequent these preventative maintenance procedures occur or if they are modified based on system configuration. In a few buildings, there were bar codes on certain pieces of equipment which are used by preventative maintenance software to track procedures. This did not appear to be consistent in all buildings. 4.7 IMPROVED PREVENTATIVE MAINTENANCE PROCEDURES It is not fully understood how the preventative maintenance team schedules their duties throughout the campus. It was noted during the site observations that air-handling unit filter changing frequency was Purdue University 4-8 Burns & McDonnell

87 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review lacking. A number of air-handling unit filters were loaded and past the recommended change date. Dirty filters result in, among other things, increased pressure-drop, which in turn increases energy consumption. When the IAQ technician is performing routine monitoring, it is recommended they should review and inspect preventative maintenance of equipment and provide feedback to the preventative maintenance teams so they can update their schedules. For example, if an IAQ technician identifies that an airhandling unit has filters that are dirty (loaded) after two months and should be changed in the near future, that information should be relayed to the preventative maintenance teams so they can update their schedule from three months to two months. Each system should have a unique preventative maintenance schedule developed rather than a one size fits all approach. 4.8 CONTROL SYSTEM GRAPHICS AND INFORMATION UPGRADE It is recommended that Purdue continue to create dynamic interface graphics for all new installations. These graphics should include all data and monitoring points depicted on the equipment they are associated with. A graphics implementation plan should include upgrading all existing control system points to a user-friendly interface. These graphics can be a vital tool in assisting in troubleshooting thermal comfort issues. Providing graphical user interfaces would allow the IAQ technician to see a snapshot of the system in question and provide more detailed information to the Building Systems Group regarding the issue. Along with a graphical interface, a detailed operating procedure sheet should also be created and provided to the IAQ technicians to improve their understanding of the overall operation of the equipment. It is recommended that the operating procedure sheet be posted at the unit next to the control system diagrams that already exist. The graphical software depicting the system should allow the programmer to add the detailed sequence of operation documentation as an attachment to the graphics page. This would allow the Building Systems Group to be the keeper of the current version of the document. Utilizing engineering students to create graphics and data sheets could provide a low-cost option for updating the existing systems. For this and future control system upgrades, it is recommended that Purdue rely on commercially available controls contractors who have experience in campus systems and who are presently involved on the campus. Involving outside contractors for the development of graphics and updating control sequences will allow the console group the time and ability to continue performing facility optimization projects and the ability to assist the IAQ techs in diagnosing control system issues. Purdue University 4-9 Burns & McDonnell

88 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review 4.9 EXPANDING SEQUENCE OF OPERATION STANDARDS Below are recommended alterations to the existing standard sequence of operations along with recommended additional strategies to consider: Variable Air Volume Unit Control: In this control sequence, the peak cooling the airflow setpoint is the maximum amount of air the VAV box is set to deliver. As cooling requirements decrease, airflow decreases until it reaches its minimum setpoint. This setpoint will be based on the minimum controllable level of the VAV box or the required ventilation rate, whichever is higher. When it reaches this minimum, the system is in its deadband and is neither heating or cooling. As the system moves into heating mode, the sequence has two phases. In the initial phase of heating, the airflow will remain at the minimum airflow rate and the reheat valve will modulate to full open. If additional heating is required, the airflow rate will increase until it reaches a maximum heating airflow setpoint. During both of these phases, the VAV box maintains a constant supply air discharge temperature to the room. This requires a sensor that monitors the temperature of the supply air discharge. In the heating phases, the supply air discharge temperature should be approximately 90 F; air temperature should not be allowed to get too hot to prevent stratification and short circuiting of the hot air to the return plenum. Fan Static Pressure Reset Control: In this strategy, the critical VAV zone changes as loads vary throughout the building. Instead of maintaining a constant pressure setpoint at a specific area, the setpoint must be reset constantly so that it maintains the static pressure required by the critical zone. The critical zone is identified as the VAV damper that is wide open or running at its maximum. Generally polling all VAV damper positions every minute and making small adjustments to the static pressure setpoint provides stable control. Limiting the minimum and maximum amount of setpoint adjustment is recommended in the instance of a VAV damper failure, or communication failure. This strategy allows fans to operate at generally lower static pressures. Studies have shown that 30%-50% of the fan energy can be saved using this technique. This strategy should be used in conjunction with Supply Air Temperature Reset, but not programmed to occur simultaneously. Pump Pressure Control: Similar to fan static pressure reset control, but the system would poll all of the associated valve positions and adjust the setpoint accordingly. AHU Supply Air Temperature Control: Supply air temperature from VAV AHUs can be reset similar to Fan Static Pressure Control based on polling of the VAV dampers. Maximum energy savings usually occur by allowing fan static pressure to be reset first, and then supply air temperature. Purdue University 4-10 Burns & McDonnell

89 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review Occupancy Sensor Setback Control: For spaces with occupancy sensors, upon detection that the space is not occupied, reset the temperature and airflow requirements. For example, if a space is served by an AHU or VAV and there is no occupancy, reduce the airflow setpoints to the space to 100 cfm and increase the space temperature deadband to 5. Minimum Ventilation Rate: ASHRAE 62.1 Ventilation Rate Procedure Building Static Pressure Control: As building pressure rises, modulate open the relief damper to maintain building pressure setpoint. If the relief damper modulates to full open for (a predetermined) time delay and the building pressure is greater than the setpoint, enable the relief fan and modulate to maintain setpoint. If the relief fan is running at minimum speed for (a predetermined) time delay and the building pressure is less than the space setpoint, disable the fan and proceed to modulate the relief damper closed to maintain the setpoint. Provide an end-switch (position indicator) with the damper motor to verify damper is open before enabling the fan. Humidity Control: Modulate the humidifier based on exhaust/return humidity. Reset the humidity setpoint based on outside air temperature. Heat Recovery Runaround Loop Control: Enable the pump when the outside air temperature is less than 50 or greater than 80 and the supply and exhaust fan are operating. Modulate the three-way valve to maintain the heat recovery coil leaving temperature at the unit supply air temperature setpoint. Alarms: Provide the following alarms to be routed to responsible parties. o Low Mixed Air Temperature 45 (ADJ) o Low Supply Air Temperature 50 (ADJ) o High Supply Air Temperature 95 (ADJ) o Low Space Temperature 5 below heating setpoint (ADJ) o High Space Temperature 5 above cooling setpoint (ADJ) o Low Return Air Temperature 50 (ADJ) o High Return Air Temperature 90 (ADJ) o Low Return Air Humidity 25% (ADJ) o High Return Air Humidity 60% (ADJ) 4.10 SHARING OF INFORMATION It is recommended that IAQ teams meet with their team leaders on a regular basis to discuss system operation and energy efficiency procedures. The team leaders should identify improvement ideas and methods and share them with the Physical Facilities management and groups that are responsible for the energy conservation throughout the University. Ideas from the technicians at the building controls level Purdue University 4-11 Burns & McDonnell

90 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review can prove to be invaluable in implementing improvements throughout the University campus including, but not limited to, updating sequence of operations, improved preventative maintenance procedures, and energy efficiency improvements CONTINUOUS COMMISSIONING EFFORT Currently the Energy group has performed a number of retro-commissioning (RCx) efforts on campus. It is recommended that these efforts continue on existing buildings. The building list should be ranked in order starting with buildings consuming the most energy, the most energy per square foot and buildings with a high number of trouble calls. RCx identifies low-cost operational and maintenance improvements in existing buildings and focuses on dynamic energy using systems with the goal of reducing energy waste and obtaining energy cost savings. RCx focuses on energy using equipment such as mechanical, lighting, and related controls to optimize system performance rather than relying on major equipment replacement. The results from a RCx study can improve indoor air quality, comfort, controls, energy efficiency, reduce occupant complaints, and increase equipment life. A general RCx process includes: 1. Analyze past two years utility records/bills (where available building submeters are installed) 2. Interview facility personnel/users 3. Diagnostic monitoring 4. Functional performance testing 5. Operational issues and most cost-effective opportunities compiled and submitted in report 6. Follow up to determine if the identified actions have been implemented. 7. Ongoing commissioning: Continual re-commissioning focusing on completed improvements. The process incorporates monitoring and analysis of building performance data to calculate the actual savings ENERGY/UTILITY MONITORING It is recommended that Purdue implement an energy and utility monitoring program which can be a valuable tool for operation of a building and reducing energy consumption. Some of the benefits of a utility monitoring system include: 1. Access to real-time and historical load information. 2. Identifying buildings that may benefit from retro-commissioning. 3. Identifying operational and maintenance issues. 4. Allocation of costs to specific loads or specific buildings. 5. Provides accurate budgeting forecasts and future consumptions. 6. Measurement and verification for conservation measures. Purdue University 4-12 Burns & McDonnell

91 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review Educating the staff, students, and the public on Purdue s dedication to reduce energy on campus would help foster behavioral modifications, enhance the learning environment in regards to sustainability and renewable energy sources, and help to attract and retain students and staff. The belief is that educated decision makers will make better choices, and voluntarily curtail at least some of the energy impacts. An energy awareness and education plan could be implemented and made available to all students and campus occupants through the internet displaying energy usage and reduction efforts throughout campus. This system could be used as a teaching tool in classes and as a data source for research work. Below are some examples of an interactive web tool that displays energy usage for Arizona State University. Figure 4-7: Building Energy Assessment Tool (1 of 3) Purdue University 4-13 Burns & McDonnell

92 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review Figure 4-8: Building Energy Assessment Tool (2 of 3) Figure 4-9: Building Energy Assessment Tool (3 of 3) There is a plan in place to utilize InStep edna software to capture data from the Siemens, ALC, and utility meters to provide feedback on the energy usage throughout campus. Part of this plan also includes upgrading the Siemens platform to a dedicated IT server. It was noted that flow meters were recently installed on some of the chilled water supply and return piping entering the buildings. The installation Purdue University 4-14 Burns & McDonnell

93 Comprehensive Energy Master Plan FINAL DRAFT 4.0 Control System Review was incomplete on most of these meters, and they were not communicating with the building automation system. We recommend that the meter installation be completed and sensors commissioned. * * * * * Purdue University 4-15 Burns & McDonnell

94 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options 5.0 RENEWABLE AND ALTERNATIVE ENERGY OPTIONS Chapter provided by Purdue University 5.1 INTRODUCTION According to the U.S. Energy Information Administration, the net electricity generation by fuel in the United States in 2010 was: 45% - Coal 23% - Natural Gas 20% - Nuclear 6% - Hydro 4% - Other renewable (includes wind, photovoltaic, biomass, and geothermal) 2% - Other non-renewable fuels Purdue continues to evaluate renewable and alternative energy options to be feasible alternatives to its existing generation portfolio. Much of the overview information in this chapter contains excerpts from the 2010 Indiana Renewable Energy Resource Study that was prepared by the State Utility Forecast Group for the Indiana Regulatory Commission and Regulatory Flexibility Committee of the Indiana General Assembly and was published in September of The State Utility Forecast Group is part of the Energy Center at Discovery Park at Purdue University. The full 129 page study is available on-line. The balance of this chapter looks at some of the available renewable and alternative energy options, including information on the test burns that we have conducted at our plant. 5.2 ALTERNATIVE FUEL CO-FIRING An economical way to use alternative fuels in an existing fossil fuel power plant is to co-fire biomass with coal in the existing plant. Co-fired projects are usually implemented by retrofitting a biomass fuel feed system to an existing coal plant. Co-firing biomass in a coal plant generally has overall positive environmental effects. The clean biomass fuel typically reduces emissions of sulfur, net carbon dioxide, ash, and heavy metals, such as mercury. Overall emissions of NOx and carbon dioxide typically increase slightly, depending on the application and the ratio of co-firing. Identifying the available biomass resources is a key early step in using this fuel, which may have economic benefits over coal as well. Purdue University 5-1 Burns & McDonnell

95 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options Organic Waste Biomass Organic waste biomass can be divided into several subcategories that include the following: Agriculture crop residues: Crop residues include biomass, primarily stalks and leave, not harvested or removed from the fields in commercial use. Examples include corn stover (stalks, leaves, husks and cobs), wheat straw, and rice straw. With approximately 80 million acres of corn planted annually, corn stover may become a major biomass resource for bioenergy applications in the Midwest. Forestry residues: Forestry residues include biomass not harvested or removed from logging sites in commercial hardwood and softwood stands as well as material resulting from forest management operations, such as pre-commercial thinnings and removal of dead and dying trees. Municipal solid waste (MSW): Residential, commercial, and institutional postconsumer wastes contain a significant proportion of plant derived organic material that constitutes a renewable energy resource. Waste paper, cardboard, wood waste and yard wastes are examples of biomass resources in municipal wastes. Biomass processing residues: All processing of biomass yields byproducts and waste streams collectively called residues, which have significant energy potential. Residues are simple to use because they have already been collected. For example, processing of wood for products or pulp produces sawdust and collection of bark, branches and leaves/needles. Animal wastes: Farms and animal processing operations create animal wastes that constitute a complex source of organic materials with environmental consequences. These wastes can be used to make many products, including energy Energy Crops Energy crops are not being commercially grown in the United States at present although a few demonstration projects are underway with DOE funding. The Bioenergy Feedstock Development Program at Oak Ridge National Labs has identified hybrid poplars, hybrid willows, and switchgrass as having the greatest potential for dedicated energy use over a wide geographic range. Switchgrass falls under the category of herbaceous energy crops. These energy crops are perennials that are harvested annually after taking two to three years to reach full productivity. The hybrid poplar and Purdue University 5-2 Burns & McDonnell

96 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options hybrid willow are short rotation, fast growing hardwood trees. They are harvested within five to eight years after planting. While Indiana has a huge potential for energy crops, it is unlikely that farmers will utilize prime farmland for an uncertain return on energy crops. It is more likely that marginal lands will be used. Switchgrass has been identified as the most effective energy crop for most of the Midwest including Indiana. The following reasons were used to justify this claim: It is native to most of the Midwest; It does not require much input after planting, therefore there is less soil disturbance; With less soil disturbance there is less chance of soil erosion; Harvest usually occurs from September to October prior to the harvest of corn and soybeans; and Machinery required for switchgrass is similar to that used for hay or silage harvest. The central region of the state has the highest potential for switchgrass production because of favorable soils and a high percentage of agricultural lands. The southern region has the least potential and the northern region has a fairly high potential Material Waste Biomass Tire-Derived Fuel or TDF, is processed used tires from truck and cars. The beadwire is removed and recycled and the remaining tread and sidewall cut into pieces that can be used along with coal in a coal fired boiler. It is used because of its high heating value. Compared to other commonly used solid fuels, the heating value is 25-50% higher than coal and % higher than wood. Facilities such as utility boilers, cement kilns, and pulp/paper mills use TDF as supplemental fuel in their energy-intensive processes. State and Federal studies have repeatedly shown that using tires to generate energy is environmentally sound when used in appropriate applications that ensure complete combustion, have proper air pollution controls in place, and conduct all required testing, monitoring, and other regulatory requirements. An additional advantage is the reduction in the number of scrap tires going to landfills. 5.3 PURDUE AND ALTERNATIVE FUELS Purdue University s Wade Utility Plant has evaluated a variety of potential alternatives to coal as possible fuels for the coal-fired boilers. A number of factors are considered when evaluating a potential fuel and only a few alternative fuels have met the basic considerations adequately enough to warrant a test burn. Purdue University 5-3 Burns & McDonnell

97 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options Factors considered when evaluating an alternative fuel: Fuel chemical characteristics: The Btu value of the alternative fuel must be high enough to produce a net energy gain in the boilers The alternative fuel must not be considered a waste under the US EPA s definition of waste. Wade s boilers are not permitted to burn wastes. The ash fusion temperature, ash content, sulfur content, metals content, and moisture content for fuels considered for use in the stoker fired boilers must be similar to the current coal quality so as not to cause permit issues or operational problems. Alternative fuels must be clean and free of foreign material Fuel physical characteristics: Because the stoker boilers and the CFB both lack a second fuel feed system, any fuels to be considered for a test burn must be able to be handled using existing yard storage, plant transfer, plant storage, and boiler feed equipment. E.g., the stoker fired boilers cannot use fuels with high moisture content or that segregate in the plant storage systems; the CFB boiler cannot use fuels that interfere with the boiler solids recirculation system or that interfere with the coal crusher Economics: The alternative fuel must be available delivered at a cost competitive with coal for the plant (cost comparison depends upon the fuel being displaced: depending CFB coal or stoker coal) or competitive with natural gas fueled boilers. The alternative fuel cannot require inordinate handling/processing time on the part of Wade staff. Most biomass fuels are less dense than coal, so transporting the biomass can add significantly to the costs Availability: For reliability of supply, the alternative fuel under consideration must be currently available in significant enough volumes and not speculative. As a state funded institution, Purdue University is mandated by Indiana Code to purchase coal mined in Indiana. In keeping with the spirit of this code requirement, Indiana sourced alternative fuels are preferred. Purdue University 5-4 Burns & McDonnell

98 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options Typical evaluation process: Evaluate chemical and physical characteristics to determine technical viability as a fuel in one of Wade s boilers. Evaluate economic and supply characteristics. Schedule and conduct test burn (the Indiana Department of Environmental Management allows up to 30 operating days of test firing with an alternative fuel without permit modification as long as the alternative fuel will not cause the emission unit to exceed permit limits. The evaluation process is used to determine whether there are any operational or maintenance impacts on the boiler with the alternative fuel. Perform boiler stack testing to compare 100% coal emissions to coal/alternative fuel blend. This data is used for possible permit modification to allow the plant to use the alternative fuel on an ongoing basis. If the test burn is successful and the fuel is delivered reliably at an economically acceptable rate, the fuel could be incorporated into the operating permit Fuels considered as alternative fuels for Wade s boilers in the past: Fuels considered: Tire derived fuel Clean wood waste (e.g., pallets, etc.) Used railroad ties Animal manure Refuse derived fuel (both pellets and cubes) Fuel crops: o Switchgrass (direct fed and pellets) o Miscanthus o Poplar Dried distillers grain solids ( DDGS, a byproduct of ethanol production) Gluten feed pellet (a locally available byproduct of corn syrup production) Corn starch (locally available) Corn stover (locally available) Petroleum coke ( pet coke ) Purdue University 5-5 Burns & McDonnell

99 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options Fuels test burned Pet coke (Boiler 5, 1992) Tire derived fuel (Boiler 2, 2001) Tire derived fuel (Boiler 5, 2005) Corn stover (Boiler 2, 2010 and 2011). 5.4 SOLAR Thermal There are ways to generate electricity utilizing solar thermal technology, but practicality and economics are contingent on the annual solar radiation of the installation. Indiana has relatively little potential for grid-connected solar thermal projects to generate electricity because of the lack of annual solar radiation. There is, however, some potential for heating potable water (swimming pool and domestic) and building heating using flat-plate collectors Photovoltaic Cells Unlike solar thermal systems, photovoltaic (PV) cells allow the direct conversion of photons in sunlight into electricity. While Indiana does not have excellent solar resources, there is some potential for fixed, flat-plate PV systems. The high installation costs are offset by little or no operating costs, since there is no fuel required and there are no moving parts. Energy from PV systems currently ranges from 20 cents/kwh to 50 cents/kwh. A lot of research continues to be done on PV systems and the price has declined an average of 4% per year over the past 15 years. The Department of Energy has an initiative called SunShot to get the current capital cost of utility scale PV system from $4-5 per watt down to $1 per watt by WIND Wind power systems convert the movement of air to power by means of a rotating turbine and a generator. Wind power has been among the fastest growing energy sources over the last decade, with around 30 percent annual growth in worldwide capacity over the last 5 years. Total installed wind capacity in the United States exceeded 35,000 MW as of December The US wind market has been driven by a combination of growing state mandates and the Production Tax Credit (PTC), which provides an economic incentive for wind power. The PTC has been renewed several times and is currently set to expire on December 31, Typical utility-scale on-shore wind energy systems consist of multiple Purdue University 5-6 Burns & McDonnell

100 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options wind turbines that range in size from 1.5 MW to 3 MW produced by companies like Vestas, GE, and Siemens. The use of single, smaller turbines is also common in the United States for powering schools, factories, water treatment plants, and other distributed loads. Community wind projects in the U.S. involve a cluster of turbines, sometimes as part of a larger utility-scale wind farm, to provide power for a town, a large campus or other facility. Wind is an intermittent resource, with average capacity factors ranging from 25 to 40 percent in Indiana. The capacity factor is the percentage of time that the turbines are generating electricity. The capacity factor of an installation depends on the wind potential in the area and the energy capture characteristics of the wind turbine. Capacity factor directly affects economic performance; thus, reasonably strong wind sites are required for cost-effective installations. Since wind is intermittent, it cannot be relied upon as firm capacity for peak power demands. To provide a dependable resource, wind energy systems may be coupled with some type of energy storage to provide power when required, but this is not common and adds considerable expense to a system. In the Midwest, average wind power is highest in the winter and spring, while it is lowest in the summer when demand is the highest. In Indiana, the meteorological wind data reflects that the wind is more prevalent at night when the demand for electricity is reduced. 5.6 GEOTHERMAL HEAT PUMP There are two methods in which geothermal heat may be employed as an energy source for a customer. The first way and the way most commonly thought of is to draw high temperature heat from the earth s core for direct heating and steam generation. The heat from hot ground areas, such as Yellowstone National Park and the volcanic island of Iceland are examples of geothermal sources. Iceland generates most of the electricity used on the island utilizing high temperature geothermal energy. The second way to utilize geothermal energy and the way most commonly available is to use the earth as a low temperature heat source in the winter and heat sink in the summer in connection with heat pump technology. By using water source heat pumps, low temperature heat, say 40 to 50 F, can be extracted from the earth and then increased in temperature to a temperature, say 110 to 130 F, suitable for space heating. Low temperature geothermal heat with heat pump systems requires a way to get the heat from deep in the ground, and there are several ways, which are: Purdue University 5-7 Burns & McDonnell

101 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options Well water extraction Deep river water extraction Horizontal closed loop field Vertical closed loop field Individuals and organizations with longer return on investment (ROI) horizons are adopting geothermal across the State, even though Indiana is not known for high value geothermal assets. Technologies have improved and costs have fallen, making some geothermal applications attractive in Indiana. Among the larger adopters, for example, is Ball State University which is replacing its coal fired campus central heating boilers with geothermal heat pump systems (with partial Federal funding of $5M). The Ball State system is not yet operational. 5.7 ENERGY STORAGE Energy storage allows the reduction of production capacity by shaving the peaks in instantaneous demand. In the end with energy storage, the amount of building energy consumption, in terms of kwhs or BTUs, is not reduced, but the rate of production, in terms of kwhs or BTUs per hour, can be reduced and load swings can be minimized. The result can be more efficient operation with energy production assets, delayed need for the addition of energy production capacity, and possibly the retirement of some energy production assets. 5.8 IMPLEMENTATION ISSUES Many of the renewable technologies such as wind and photovoltaic are variable and difficult to accurately predict electricity output more than 24 hours into the future. Furthermore, integrating a variable or intermittent electricity generator into an existing operation or grid is difficult and sometime results in base loaded generation sources increasing emissions because of the flexing of those sources to compensate for the variable load. Energy storage technology and smart grids are critical for these systems to be cost effective for utility scale installations such as Purdue. Utility scale battery storage is still in development. Purdue is considering thermal energy storage (chilled water) to take advantage of the pricing differential of electricity between high and low demand periods. This thermal energy storage would also be effective to integrate the variability of electricity generated by wind into Purdue s energy portfolio. Purdue University 5-8 Burns & McDonnell

102 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options 5.9 PURDUE AND WIND ENERGY Purdue s Animal Sciences Research and Education Center ( ASREC ), a 1700 acre plot west of campus, has hosted a meteorological tower for six years. The data collected thus far from the tower indicate that the wind resources in this area are substantial. The University could pursue a MW installation at this site (approx ½ peak demand on the campus). As of the date of this plan, Purdue is working with a developer in the hopes of utilizing wind as a partial fuel source of Purdue s electricity portfolio. In addition, several years ago, a team of EPICS students proposed installing a small wind turbine on the northwest corner of campus to power the intramural field lights PURDUE AND SOLAR ENERGY Purdue has a small PV array installed at the Beck Agricultural Center installed with the assistance of Duke Energy Indiana. Other solar opportunities that have not been studied extensively include the application of solar thermal to the campus condensate storage tank 5.11 PURDUE AND ANAEROBIC DIGESTION ENERGY PRODUCTION Purdue s ASREC farm has manure supplies that could be used as sources of energy through anaerobic digestion. Currently the manure is held in lagoons and land applied as a nutrient source for crops. A large portion of Purdue s food waste form the residence halls is collected and used as a fuel for the City of West Lafayette s anaerobic digester at the waste water treatment plant. Gas from the digester powers microturbines used for electricity production at the plant PURDUE AND GEOTHERMAL HEAT PUMPS There is an opportunity for application of a ground source heat pump system for added cooling of Purdue s chilled water return lines. This opportunity has not been evaluated for technical or economic feasibility RENEWABLE AND ALTERNATIVE ENERGY OPTIONS SUMMARY With the exception of wind that is still under evaluation, the other renewable and alternative energies are becoming more attractive, but are currently not feasible to implement at Purdue. It is important that Purdue continues to be both environmentally and fiscally responsible, and will continue to evaluate the economics and implications of incorporating renewable and alternative energies into our portfolio every few years or as economics change and technologies progress. Purdue University 5-9 Burns & McDonnell

103 Comprehensive Energy Master Plan FINAL DRAFT 5.0 Renewable and Alternative Energy Options New tax credits (for taxpaying entities), incentives, increased monetary valuation of environmental benefits, or sustained high prices for fossil fuels could make these other fuel sources more economically viable in the future. References Indiana Renewable Energy Resources Study, State Utility Forecasting Group, Energy Center At Discovery Park, Purdue University * * * * * Purdue University 5-10 Burns & McDonnell

104 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling 6.0 PRODUCTION MODELING Based upon utility demand information provided by Purdue University staff, recommendations were developed for short and long term approaches for campus utility production facilities and distribution systems. A detailed analysis of the distribution system options is included in Section 8.0. However, the production plan outlined below was developed with regard to short and long term distribution capacity and barriers. Steam, chilled water, and electricity production plans are presented below with regard to the total load growth across campus. The plans span at least a 20 year timeline and include a longer horizon where necessary to illustrate significant plan implementations. The production modeling effort focused on six primary challenges to meet future campus demands. 1. Determine the impacts and barriers at the Wade Utility Plant to remove curtailment of chilled water on campus. Currently the campus building s HVAC systems are operated to reduce the cooling load during times of high demand due to perceived cooling system limitations (primarily cooling towers) at the Wade Utility Plant. The cooling towers at the Wade Utility Plant serve the chillers, Steam Turbine Generator 1, and other ancillary loads. 2. Investigate the need to install a third chilled water plant at the main campus. The goal is to recommend the proper size, location, and construction timing with careful regard to load growth and distribution limitations. 3. Provide an overall chilled water capacity roadmap for the campus, including an analysis of whether steam or electric driven assets should be installed in the future. 4. Provide a plan to meet future steam capacity needs with regard to demand growth, existing asset retirement, and distribution capacity. 5. Provide a plan to meet future electricity needs with regard to demand growth, existing asset retirement, and distribution capacity. 6. The utilization of the existing Wade Utility Plant pump and fan steam drives. Many of these auxiliaries have the redundant ability to be driven electrically or by steam produced at the plant. The goal of this analysis was to determine the cost effective utilization of these assets. In addition to the items listed above the viability of installing Thermal Energy Storage (TES) and Combined Heat and Power (CHP) capacity were investigated for installation within the next few years. TES and CHP are both integral to the analysis of the production options for the Comprehensive Energy Master Plan and are part the plans outlined herein. Purdue University 6-11 Burns & McDonnell

105 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling 6.1 APPROACH Many of the scenarios investigated to establish a production capacity implementation plan utilized hourly dispatch models developed to for this analysis. These models preferentially dispatch existing and future chilled water, steam, and electric production assets to optimize economic performance. In particular these models were used to determine the value of steam driven assets and determine their future value as part of the production implementation plan. 6.2 DEMAND PROFILES Chilled water, steam, and electricity load projections were supplied by Purdue. Those loads were factored against the current demand to generate future demand. These demands do not consider any building renovation impacts and are illustrated in the graphs below. (Note: If Purdue implements measures to decrease peak building energy usage, the recommendations are still valid, but the timing of the implementation would be decelerated. See Section 12.0 for specific information.) On average these graphs represent a 1-2% annual increase in peak and total annual energy consumption. Figure 6-1: Chilled Water Load Growth Purdue University 6-12 Burns & McDonnell

106 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Figure 6-2: Steam Load Growth Figure 6-3: Electric Load Growth Purdue University 6-13 Burns & McDonnell

107 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling 6.3 PRODUCTION CAPACITY The following tables represent the existing assets considered as part of this analysis. Asset retirement schedules were considered as part of the short and long term production plans. Retirement dates were either provided by University staff, estimated based on similar assumed life expectancies established at Purdue, or typical industry standards. Table 6-1: Existing Chilled Water Production Assets Chiller Capacity Driver Location Install. Mfr. Number (Tons) Date 1 2,000 Electric NW Chiller 2002 Trane Plant 2 2,000 Electric NW Chiller 2002 Trane Plant 3 2,000 Electric NW Chiller 2005 Trane Plant 4 2,700 Electric NW Chiller 2007 Trane Plant 5 2,700 Electric NW Chiller 2007 Trane Plant 6 6,250 Steam Wade 1971 Carrier 7 3,000 Steam Wade 1988 York 8 4,500 Steam Wade 1994 Carrier 9 2,000 Electric Wade 1999 Trane 10 2,000 Electric Wade 2000 Trane 11 5,000 Steam Wade 2001 York Boiler Number Fuel Coal (Stoker) Coal (Stoker) Natural Gas Coal (CFB) Natural Gas Install. Date Table 6-2: Existing Steam Production Assets De- De- Rated Rated Rated Rated Rated Steam Fuel De- Rated Flow Steam Fuel Output Input Output Input lb/hr MMB/h MMB/h lb/h MMB/h MMB/h , , , , , Purdue University 6-14 Burns & McDonnell

108 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Turbine Number 1 Configuration Extraction / Condensing 2 Backpressure Table 6-3: Existing Dispatched Electricity Production Assets Throttle Conditions 600 psig / 810 F / 250,000 lb/h 600 psig / 825 F / 265,000 lb/h Extraction Pressure Exhaust Pressure Rated Capacity Install. Date Mfr. 125 psig 2.5 inhg 30 MW 1995 GE 120 psig 15 psig 10 MW 1967 GE The existing diesel generator was not considered as an economical electrical production asset. However, the analysis assumes it remains available to provide black start capacity at the Wade Utility Plant. 6.4 PRODUCTION OPTIONS Overview of CHP and TES Analysis and Results Analysis of Combined Heat and Power (CHP) and Thermal Energy Storage (TES) for Purdue utilized a multi-step process. The first effort was to determine the feasibility and fiscal impact of installing a 5-15MW of CHP and TES capacity at Purdue University to meet existing and future thermal and electric loads. This analysis was completed in two phases. First, an initial screening analysis was performed to determine general viability. Both CHP and TES showed favorable results. Then, a more detailed analysis was performed for implementing CHP. The installation of CHP capacity in lieu of traditional capacity can provide substantial efficiency, environmental and economic benefits. For this analysis, natural gas fired combustion turbines were used to make power. As a byproduct of this process, high temperature exhaust gas is created. This heat source is utilized to make steam to meet campus thermal and electric loads through the use of existing steam turbines. The hot gas produced provides a significant thermal energy source without consuming additional fuel above that used to create power. Figure 1 from the EPA s Catalog of CHP Technologies, shows the efficiency advantage of CHP compared with conventional central station power generation from a local utility and onsite boilers. When considering both thermal and electrical processes together, CHP typically requires only 65% of the primary energy separate heat and power systems require. CHP systems utilize less fuel than separate heat and power generation, while providing the same level of output, resulting in fewer emissions. Purdue University 6-15 Burns & McDonnell

109 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Figure 6-4: CHP versus Separate Heat and Power Production Note: Assumes national averages for grid electricity and incorporates electricity transmission losses. The purpose of the thermal energy storage (TES) analysis was to determine if TES can potentially be a viable solution for Purdue University to offset or delay capital costs and improve operating costs. The analysis provided information related to total cost of ownership capital costs, energy costs, and operation and maintenance (O&M) costs for TES to offset the planned capital improvement of additional electric driven chillers. TES accomplishes these goals by creating useful thermal energy at night during periods of low electric cost and low thermal demand, storing that energy, and deploying it during peak hours when electricity is expensive. During these peak hours, several chillers can remain offline and the installation of additional capacity may be delayed. Figure 6-5: Example TES Dispatch Strategy Purdue University 6-16 Burns & McDonnell

110 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Initial TES and CHP Analysis and Results TES To meet the additional demand for chilled water, thermal energy storage (TES) was evaluated in an effort to meet the increased chilled water demand in lieu of additional chiller capacity. Several options were evaluated including dispatching steam chillers or electric chillers first, providing chilled water with or without TES. Trane TRACE modeling software was used to model and forecast future conditions for Purdue University based on the loads provided and weather conditions within the program. A model of the Wade Utility Plant and Northwest Chiller Plant was developed utilizing existing chiller efficiencies, chilled water pump horsepowers, condenser water pump horsepowers, and cooling tower fan horsepowers. The model plant was then calibrated to match existing conditions and loads to the best extent possible. Once the base case was calibrated, a model was created utilizing the projected increased peak load as provided by Purdue. The thermal energy storage tank was initially sized to offset additional cooling capacity (5700 tons) that would be needed to meet chilled water demand at peak load. This approach projects that a 33,500 ton-hr tank was required. A thermal energy storage tank was added to the model and analyzed in the options. This strategy allows for a portion of the load to be shifted to non-peak hours of the day for everyday of the year. The charge and discharge strategy of the tank is optimized based on current equipment capacities, efficiencies, daily peak tonnage, and utility costs. The inclusion of thermal energy storage also assists at removing the need for Purdue to enter into curtailment to reduce building chilled water loads CHP The equipment selected to serve as the basis for CHP evaluation was based on the 2010 loads, anticipated future growth, and assets previously considered by the University. The CHP capacity analyzed consisted of a Solar Turbines Titan 130 combustion turbine generator (CTG), a duct fired heat recovery steam generator (HRSG), and supporting auxiliary equipment. This size turbine was selected based on the available electric load and anticipated steam loads. The need to supplant the steam generation currently supplied by Boiler 1 would require a larger combustion turbine. This turbine size was limited based on the available electric load. Larger combustion turbines, although more efficient, would create conditions where an appreciable amount of power would need to be exported to the utility grid to realize the efficiency benefits from a CHP system. Purdue University 6-17 Burns & McDonnell

111 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling The CHP system was compared to a traditional boiler configuration consisting of a D-type, gas fired, Low-NOx, water tube boiler. The boiler was sized based on previous studies performed by the University for adding gas fired boiler capacity. The CHP and traditional boiler options were dispatched based on meeting hourly steam and chilled water campus demands. Steam Turbine Generator 2 (TG2) was dispatched first to meet campus and plant steam loads. Steam Turbine Generator 1 (TG1) was dispatched when the steam load exceeded the capacity of TG2 or when it was advantageous to make additional power based on available steam generating capacity and the real time cost of market power. For each hour considered, the cost of generating additional electricity by utilizing the condensing steam turbine was based on the incremental cost to fuel available boiler capacity Conclusions Three main conclusions can be drawn from the analysis performed in this first step: 1. In all operating scenarios evaluated, dispatching the electric chillers first results in significant savings. This is represented by both the annual operating costs savings as well as the life cycle cost analysis. Purdue will begin to reap the energy savings as soon as the dispatch strategy is changed to dispatching the electric chillers first. This benefit is independent of implementing either TES or CHP. 2. Implementing Thermal Energy Storage (TES) results in a lower Life Cycle Cost as result of lower operating costs and deferring capital investment for additional chiller capacity in operating scenarios evaluated. Therefore TES was brought forward to analyze in further detail. 3. Implementing a Combined Heat and Power (CHP) system that consists of a natural gas fired combustion turbine with a Heat Recovery Steam Generator (HRSG) provided a lower life cycle costs in all operating scenarios evaluated when compared with a natural gas fired boiler Detailed CHP Analysis and Results Due to the favorable results outlined in the first step of the process a more detailed analysis of several CHP options was performed. The following key assumptions were used when evaluating the economic and technical viability of installing combined heat and power (CHP) capacity in lieu of traditional gas fired boiler capacity to meet future thermal and electrical campus demands. Purdue University 6-18 Burns & McDonnell

112 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Site and Equipment Assumptions 1. New steam generating assets will be installed at the Wade Utility Plant in the location of existing Boiler 1. Boiler 1 will be removed from service in May of Existing condensate, water treatment, and boiler feedwater systems will be utilized. 3. Existing chilled water systems will be utilized for combustion turbine inlet cooling. 4. A gas compressor is required to provide adequate pressure for the gas turbine included in the CHP options. 5. A selective catalytic reduction (SCR) system is not included for NOx control. 6. All future chillers will be electric centrifugal. 7. Boiler 2 is removed from service in FY The stack for Boiler 1 will be utilized for new capacity proposed Dispatch Model Assumptions 1. All steam generating assets produce steam at a constant pressure and temperature (650 psig / 825 F). 2. Analysis time frame ends in Electric chillers are dispatched before steam-driven chillers. 4. It was assumed that adequate cooling tower capacity exists for all operating scenarios. 5. The 15 psig steam admission on TG-1 was not modeled. 6. All boilers (not including the HRSG s) were modeled at a constant 86% efficiency. 7. CTG performance is based on an elevation of 590 ft above sea level. 8. All CTG options will utilize turbine inlet cooling capable of producing 55 F inlet air under all ambient conditions. 9. All electric chillers were assumed to have a constant efficiency equal to kw/ton. All steam-driven chillers were assumed to have a constant efficiency equal to 8695 BTU/Ton. This is based on historic chiller operating data provided by Purdue. 10. The chilled water system has a parasitic electric load equal to 0.28 kw/ton % of the campus steam demand is 15 psig steam, while the remaining 67% is 125 psig steam. 12. A constant 24 MMBTU/hr of miscellaneous 15 psig steam load was assumed. 13. The 125 psig to 15 psig plant auxiliary equipment load was assumed to be 4.6 MMBTU/hr. 14. The 650 psig to 125 psig plant auxiliary equipment load was assumed to be 3.8 MMBTU/hr. 15. Steam turbine performance is based on the steam turbine performance curves provided by Purdue. 16. TG-1 was assumed to be in operation from May 23 rd until September 14 th, and from November 25 th until March 8 th to match current operating profiles. TG1 is shut down in the shoulder months Purdue University 6-19 Burns & McDonnell

113 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling due to the combination of the low cost of power and limited steam load during these periods. The extraction from TG2 provides enough steam capacity to meet campus needs and is more efficient than TG Development of Options The equipment selected to serve as the basis for evaluation was based on the 2010 loads outlined above, anticipated future growth, and assets previously considered by the University. The CHP options selected for evaluation include a nominal 6.3 MW Solar Turbines Taurus 65 CTG, a nominal 8.0 MW Solar Turbines Taurus 70 CTG, and a nominal 15 MW Solar Turbines Titan 130 CTG. Each of the combustion turbine options is coupled with a duct fired heat recovery steam generator (HRSG), and supporting auxiliary equipment. The turbine sizes selected are based on the available electric load and anticipated steam loads. The need to totally supplant the steam generation currently supplied by Boiler 1 would require a larger combustion turbine. The turbine size was limited based on the available electric load. Larger combustion turbines, although more efficient, would create conditions in the near term where an appreciable amount of power would need to be exported to the grid to realize the efficiency benefits from a CHP system. Exporting power may require the University to adhere to national standards and regulations not currently enforced and would require cooperation from the local electric utility. Becoming a net exporter is typically not a profitable venture for universities. The combustion turbine selection was also limited based on turbine exhaust temperature. To match the operating conditions of the existing boilers at Wade, the HRSG must be capable of producing steam at 650 psig and 825 F. Some combustion turbines have an exhaust gas temperature as low as 700 F, and therefore would not be able to produce 825 F steam. The three combustion turbine options selected have sufficient exhaust gas temperatures for producing 825 F steam. The traditional boiler configuration consists of a D-type, gas fired, Low-NOx, water tube boiler. The boiler was sized based on previous studies performed by the University for adding gas fired boiler capacity. A summary of the assets for each option is provided below. Purdue University 6-20 Burns & McDonnell

114 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Table 6-4: Taurus 65 Combustion Turbine Generator Performance Summary Nominal Electrical Generating Capacity 6.3 MW Nominal Turbine Heat Rate 10,373 Btu/kWh (LHV) Nominal Turbine Fuel Consumption 65 MMBtu/hr (LHV) Nominal Gas Compressor Load 61 kw Unfired Steam Production Capacity 23,000 lb/hr Duct Fired Steam Production Capacity 52,000 lb/hr Duct Burner Fuel Consumption 59 MMBtu/hr (LHV) NOx Emissions 25 15% O2 CO Emissions 50 15% O2 Table 6-5: Taurus 70 Combustion Turbine Generator Performance Summary Nominal Electrical Generating Capacity 8 MW Nominal Turbine Heat Rate 9,955 Btu/kWh (LHV) Nominal Turbine Fuel Consumption 80 MMBtu/hr (LHV) Nominal Gas Compressor Load 93 kw Unfired Steam Production Capacity 25,000 lb/hr Duct Fired Steam Production Capacity 70,000 lb/hr Duct Burner Fuel Consumption 81 MMBtu/hr (LHV) NOx Emissions 25 15% O2 CO Emissions 50 15% O2 Table 6-6: Titan 130 Combustion Turbine Generator Performance Summary Nominal Electrical Generating Capacity 15 MW Nominal Turbine Heat Rate 9,695 Btu/kWh (LHV) Nominal Turbine Fuel Consumption 145 MMBtu/hr (LHV) Nominal Gas Compressor Load 193 kw Unfired Steam Production Capacity 42,000 lb/hr Duct Fired Steam Production Capacity 136,000 lb/hr Duct Burner Fuel Consumption 153 MMBtu/hr (LHV) NOx Emissions 25 15% O2 CO Emissions 50 15% O2 Table 6-7: Gas Fired Boiler Performance Summary Steam Production Capacity 200,000 lb/hr Boiler Efficiency 86% % Nominal Fuel Consumption 280 MMBtu/hr (HHV) NOx Emissions 20 15% O2 CO Emissions 50 15% O2 Purdue University 6-21 Burns & McDonnell

115 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Technical Evaluation The CHP and traditional boiler options were dispatched based on meeting hourly steam and chilled water campus demands. Steam Turbine Generator 2 (TG2) was dispatched first to meet campus and plant steam loads. Steam Turbine Generator 1 (TG1) was dispatched seasonally to match Purdue s current TG1 dispatch calendar, as follows: TG1 ON from May 23 rd until September 14 th, ON from November 25 th until March 8 th, and OFF for the remainder of the year (shoulder months). When TG1 is not in operation, the 125 psig extraction on TG2 is used to meet the steam flow required by the 125 psig steam system (up to the maximum extraction capability of TG2). When TG1 is in operation, its 125 psig extraction takes priority over the 125 psig on TG2. If the 125 psig steam demand is beyond the capability of the extraction on TG1, then TG2 will increase its extraction flow until the steam demand is met, or until the maximum extraction capability of TG2 is met. If the 125 psig steam demand cannot be fully supplied by the extractions on the steam turbines, then the remainder will be served via the 650 psig to 125 psig pressure reducing valves. If the 15 psig steam demand cannot be fully supplied by the exhaust steam of TG2, then the remainder will be served via the 125 psig to 15 psig pressure reducing valves. The 15 psig admission on TG1 was not included in the dispatch model due to its limited use. For each hour considered, the model first dispatches the steam turbines to meet the required thermal loads. The dispatch model then determines the most economical way of meeting the remaining electric demand. The model can meet this demand by dispatching the combustion turbine generator, by condensing steam in TG1, by purchasing RTP, or with a combination of the three. The Base Case and all three options assume a fixed level of Base electricity is purchased by Purdue University according to the current purchasing approach. This base purchase amount ranges from 9-19 MW per hour and reflects 2011 estimated purchases. This amount is not escalated over the analysis timeline Results The Taurus 65 provides savings over the life of the analysis and is what is assumed as part of the overall steam production capacity plan; however Purdue also has the option of installing a gas boiler to replace boiler #1 with a small difference in NPV. The Taurus 65 is recommended to be installed in the spaced vacated by Boiler 1 scheduled for demolition in Implementation of CHP will also reduce the University s overall emissions profile by further limiting the amount of electricity produced with coal assets on site or by the local utility. On an annual basis, this is estimated to be 170 tons of NOx, 940 tons of SO 2, 66,000 tons of CO 2, 16,000 metric tons of carbon and 280,000 MM Btu less fuel consumption. Purdue University 6-22 Burns & McDonnell

116 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Utilization of Steam Driven Assets The goal of this analysis is to determine the relative value of steam driven assets at the Wade Utility Plant compared to electric drives. The following tables show the auxiliary assets at the Wade Utility Plant that have the flexibility of being driven with either a steam turbine drive or an electric motor. The analysis below includes the price of steam produced by a conventional natural gas fired boiler with an efficiency of 86%. Steam produced from heat recovery steam generator (HRSG) was not evaluated. The duct firing efficiency of a HRSG is roughly 94%, and therefore the operation of steam driven assets with steam derived from a HRSG would appear slightly more attractive when compared with steam derived from a traditional natural gas fired boiler. Service No. Boiler Feedwater Chilled Water Cond. Trans. Closed Coolin g Type Power Drive Data Steam Inlet Table 6-8: Pumps Steam Outlet Motor Eff. Pump Data Flow Head HP psig psig % GPM ft Drive Install. Pump Install. 1 Electric Steam Electric Steam Electric Steam Steam Steam Steam Steam Electric Electric Electric Electric Electric Steam Electric Steam Electric Electric Purdue University 6-23 Burns & McDonnell

117 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Table 6-9: Boiler Fans Boiler Number Service 1 OFA 1 ID 1 FD 2 OFA 2 ID 2 FD 3 FD 5 PA 5 ID Type Drive Data Power Steam In Steam Out Motor Eff. HP psig psig % Drive Installed Fan Installed Steam Electric Steam Electric Steam Electric Steam Electric Steam Electric Steam Electric Steam Electric Steam Electric Steam Electric Table 6-10: Chillers No. Capacity Steam In Steam Out Driver Tons psig inhg(a) Location Install Electric NW Chiller Plant Electric NW Chiller Plant Electric NW Chiller Plant Electric NW Chiller Plant Electric NW Chiller Plant Steam Wade Steam Wade Steam Wade Electric Wade Electric Wade Steam Wade 2001 Purdue University 6-24 Burns & McDonnell

118 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling psig to 15 psig Backpressure Steam Turbine Drives The Wade Utility Plant has nine backpressure steam turbine drives that consume 125 psig steam and exhaust into the 15 psig steam system, with a combined power of about 3,000 horsepower. Seven of the nine drives serve boiler fans, one serves a small condensate transfer pump, and another serves a small closed cooling pump. The figure below shows a flow diagram of the major equipment in the Wade Utility Plant, with all 125 psig-to-15 psig backpressure steam turbine driven equipment represented as a single turbine (circled). Figure 6-6: Wade Utility Plant Flow Diagram 125 psig-to-15 psig Drives Assuming a 60% isentropic efficiency and throttle conditions of 125 psig / 575 F, the simultaneous operation of all 125 psig-to-15 psig drives at full power represents a total flow of about 90,000 lbm/hr. Purdue University 6-25 Burns & McDonnell

119 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Ramping up load on these drives will impact the steam flow distribution within the plant. As flow to the drives increases, the 125 psig header will require more steam flow, which can come from four possible sources: TG1 extraction, TG2 extraction, 650 psig-to-125 psig pressure reducing valves (PRV), or 650 psig-to-125 psig backpressure steam turbine driven equipment. Extraction refers to a connection at an intermediate point on the turbine casing where steam is taken out of the steam turbine. In addition, as load on the 125 psig-to-15 psig drives increases, exhaust flow to the 15 psig steam header will increase. If TG1 is operating, this extra supply of 15 psig steam could be condensed via the 15 psig admission on TG1. If TG1 is not operating, then the exhaust flow from TG2 must decrease (or 125 psig-to-15 psig PRV flow must decrease if they happen to be operating). These operational complexities have the following implications: Ramping up load on the 125 psig-to-15 psig drives could require condensing 15 psig steam via the TG1 admission. Ramping up load on the 125 psig-to-15 psig drives will most likely give an opportunity to produce low cost electricity via increased flow through the TG extractions; however, this benefit may be offset by a decrease in TG2 exhaust flow. If TG1 is not operating and 15 psig campus steam demand is low, the operation of 125 psig-to-15 psig steam drives may be limited if the TG2 exhaust is already meeting the 15 psig steam demands. These implications were not directly evaluated and could have some impact on the break-even ratio. The following assumptions were used to analyze the break-even ratio: 95% electric motor efficiency 86% boiler efficiency 94% steam turbine drive mechanical efficiency The cost to drive the equipment with electricity is simply the cost of electricity divided by the electric motor efficiency: The cost to drive the equipment with steam is the cost of fuel divided by the boiler efficiency and divided by the mechanical efficiency of the steam turbine drive. The units are converted from MMBTU to MWh to be consistent with the cost to drive the equipment with electricity. Purdue University 6-26 Burns & McDonnell

120 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Setting the two previous equations equal to one another represents the point at which driving the equipment with an electric motor costs exactly the same as driving the equipment with a steam turbine. Rearranging the equation then yields the break-even ratio of electricity price to fuel price: Therefore when the price of electricity (in $/MWh) is more than 4 times the price of fuel (in $/MMBTU), then it is economically advantageous to drive the 125 psig-to-15 psig equipment with steam. In the chart below, the blue line has a slope equal to 4, and represents the break-even ratio. Three different costs of fuel are shown on the chart: $3.67/MMBTU for CFB coal (which includes limestone and ash cost), $4.50/MMBTU for Stoker coal (which includes ash costs), and $5.46/MMBTU for natural gas. The break-even electricity prices that correspond to these fuels are also shown: $14.72/MWh for CFB coal, $18.04/MWh for Stoker coal, and $21.89/MWh for natural gas. In addition, three coordinates are shown where the cost of base purchase energy ($34.33/MWh) intersects with the price of each fuel. All three coordinates are above the break-even line, indicating that driving the equipment with steam is advantageous. Purdue University 6-27 Burns & McDonnell

121 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Figure 6-7: 125 psig-to-15 psig Steam Drives Break-Even Point CFB Coal Stoker Coal Natural Gas Cost of Electricity ($/MWh) Dispatch Steam Dispatch Electric Cost of Fuel ($/MMBTU) psig to 125 psig Backpressure Steam Turbine Drives The Wade Utility Plant has eight backpressure steam turbine drives that consume 650 psig steam and exhaust into the 125 psig steam system, with a combined power of about 4600 horsepower. Four of the eight drives serve boiler feedwater pumps, three serve chilled water pumps, and one serves the Boiler 5 ID fan. The figure below shows a flow diagram of the major equipment in the Wade Utility Plant, with all 650 psig-to-125 psig backpressure steam turbine driven equipment represented as a single turbine (circled). Purdue University 6-28 Burns & McDonnell

122 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Figure 6-8: Wade Utility Plant Flow Diagram 650 psig-to-125 psig Drives Although the four steam turbine driven feedwater pumps total to 2370 horsepower, the peak feedwater flow at the Wade Utility Plant can be met with roughly 900 horsepower. If all three steam-driven chilled water pumps were operating (500 HP each) concurrently with the 900 HP steam-driven Boiler #5 ID fan and one or two steam-driven feedwater pumps totaling 900 HP, then the total would be approximately 3300 HP. Assuming a 60% isentropic efficiency and throttle conditions of 650 psig / 825 F, this 3300 HP represents a total steam flow of about 85,000 lbm/hr. This steam flow exhausts to the 125 psig steam header, and therefore as these turbine drives are brought online, steam flow through one or both of the TG extractions must decrease (or steam flow through the 650 psig-to-125 psig PRV s could decrease if they happen to be operating). Compared to the operation of the 125 psig-to-15 psig steam driven equipment, which has the added benefit of increased TG extraction flow, the operation of the 650 psig-to-125 psig steam driven equipment will actually decrease TG extraction flow. In general this makes the operation of the 650 psig-to-125 psig steam driven equipment less attractive economically. Purdue University 6-29 Burns & McDonnell

123 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling In the winter when campus steam demand is high and both TG1 and TG2 are operating, then switching from electric drives to steam drives will decrease the extraction flow through TG1 and/or TG2. In TG1 and TG2, as extraction flow decreases, heat rate increases (assuming LP section flow remains constant). This increased heat rate translates to reduced electrical output from the TG s, which means the deficit will have to be purchased from the grid or produced by condensing steam in TG1. 15,000 Figure 6-9: TG1 Heat Rate 14,000 TG1 Heat Rate (BTU/kWh) 13,000 12,000 11,000 10,000 9,000 8,000 LP Section Flow (kpph) ,000 6, TG1 Extraction Flow (kpph) In the summer when campus steam demand is low and both TG1 and TG2 are operating, then turning on the 650 psig-to-125 psig steam drives will decrease the extraction flow through TG1 and/or TG2. The minimum LP section flow in TG1 is a function of TG1 extraction flow. As shown in the chart below, minimum LP section flow is 30 kpph for extraction flows above 144 kpph. Below 144 kpph, minimum LP section flow increases as extraction flow decreases; this is so that TG1 can be maintained above the minimum load point of about 7.4 MW. When TG1 is not condensing steam to beat the market price of electricity, then TG1 s LP section flow (i.e. flow to the condenser) will be held at a minimum. During the summer when campus demand is low, the TG1 extraction will most likely be operating below 144 kpph, Purdue University 6-30 Burns & McDonnell

124 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling and therefore a decrease in TG1 extraction flow will bring with it an increase in LP section flow. Thus during the summer, there may be times when switching from electric drivers to steam drivers would mean that more steam must be condensed in TG1. This may or may not be advantageous depending on the market price of electricity at that time. Figure 6-10: TG1 Minimum LP Section Flow If TG1 is already condensing steam in TG1 to beat the market price of electricity, then switching from electric drives to steam drives will not force more steam to be condensed. In this case, only extraction flow will be impacted. The reduced extraction will impact heat rate, as described above. Purdue currently takes TG heat rate into account when making dispatch decisions. Given that the operation of the 650 psig-to-125 psig steam drives will most likely result in a decrease in TG extraction flow and an increase in TG heat rate, it is recommended that, in general, the operation of these assets be limited Steam Driven Chillers The Wade Utility Plant has four chillers with condensing steam turbine drives. Chiller 6 consumes 650 psig steam and the remaining three consume 125 psig steam. All four are designed for 3 inhg(a) condenser pressure. There are also chilled water auxiliaries associated with the chiller that operate at the same steam pressure. As compared to electric driven chillers, steam driven chillers typically require roughly 30% more cooling tower and condenser water pump load for a given amount of chilled water load. Cooling tower and Purdue University 6-31 Burns & McDonnell

125 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling pumping loads were not included in the analysis below. If they were included, the results would appear more favorable for the electric chillers. The figure below shows a flow diagram of the major equipment in the Wade Utility Plant, with steam driven chillers circled. Figure 6-11: Wade Utility Plant Flow Diagram Steam Driven Chillers Based on two years (2009 and 2010) of chiller performance data provided by Purdue, the average steam driven chiller efficiency is 8700 BTU/(Ton-hr), and the average electric driven chiller efficiency is 0.55 kw/ton. Assuming a 75% isentropic efficiency and throttle conditions of 600 psig / 810 F, Chiller 6 will consume 41,000 lbm/hr at full load. Assuming a 75% isentropic efficiency and throttle conditions of 125 psig / 575 F, Chillers 7, 8, and 11 combined will consume 88,000 lbm/hr at full load. Purdue University 6-32 Burns & McDonnell

126 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Unlike the other steam-driven equipment in the Wade Utility Plant, the operation of Wade Chiller 6 does not directly affect the flow to TG1 and TG2. The operation of the 125 psig chillers will have the added benefit of increasing 125 psig steam header demand, which will give an opportunity to produce low cost electricity via increased flow through the TG extractions. Because of these differences, Wade Chiller 6 will be analyzed separately from the 125 psig steam chillers Wade Chiller 6 The following assumptions were used in the analysis below: 0.55 kw/ton electric driven chiller efficiency 86% boiler efficiency 8700 BTU/(Ton-hr) steam driven chiller efficiency The cost to drive an electric chiller is as follows: The cost to drive Chiller 6 is the chiller efficiency multiplied by the cost of fuel and divided by the boiler efficiency: By setting the two previous equations equal to one another represents the point at which producing chilled water with Chiller 6 costs exactly the same as producing chilled water with an electric driven chiller. Rearranging the equation then yields the break-even ratio of electricity price to fuel price: Therefore when the price of electricity (in $/MWh) is more than 18.4 times the price of fuel (in $/MMBTU), then it is economically advantageous to dispatch Chiller 6 instead of an electrically driven chiller. In the chart below, the blue line has a slope equal to 18.4, and represents the break-even ratio. Three different costs of fuel are shown on the chart: $3.67/MMBTU for CFB coal (which includes limestone and ash cost), $4.50/MMBTU for Stoker coal (which includes ash cost), and $5.46/MMBTU for natural gas. The break-even electricity prices that correspond to these fuels are also shown: $67.50/MWh for CFB coal, $82.77/MWh for Stoker coal, and $100.10/MWh for natural gas. In addition, Purdue University 6-33 Burns & McDonnell

127 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling three coordinates are shown where the cost of base purchase energy ($34.33/MWh) intersects with the price of each fuel. All three coordinates are below the break-even line, indicating that driving the equipment electrically is advantageous. Therefore Purdue should only operate Chiller 6 as a last resort after all equipment is dispatched. This matches the current operating philosophy. Figure 6-12: Wade Chiller 6 Break-Even Ratio Dispatch Steam Dispatch Electric Cost of Electricity ($/MWh) CFB Coal Stoker Coal Natural Gas Cost of Fuel ($/MMBTU) psig Steam Chillers As discussed above, the operation of the 125 psig chillers will have the added benefit of increasing 125 psig steam header demand, which will give an opportunity to produce low cost electricity via increased flow through the TG extractions. This benefit is included in the analysis below. The following assumptions were used in the analysis below: 0.55 kw/ton electric driven chiller efficiency 86% boiler efficiency 8700 BTU/(Ton-hr) steam driven chiller efficiency Purdue University 6-34 Burns & McDonnell

128 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling The mass flow rate of steam to the chiller is equal to the chiller steam load divided by the enthalpy drop across the chiller. Assuming that the incremental mass flow rate through the turbine-generator extraction is equal to the mass flow rate to the chiller, the mass flow rate of steam to the chiller will be equal to the incremental turbine-generator HP section steam load divided by the enthalpy drop across the HP section of the turbine-generator (in actuality, the incremental mass flow rate through the turbine-generator extraction could be somewhat more, or significantly less than the mass flow rate of steam to the chiller, depending on the operation of TG1, TG2, and the PRV s): Therefore the ratio of incremental turbine-generator HP section steam load to chiller steam load will be as follows: The cost to drive an electric chiller is as follows: The cost to drive a steam chiller is the chiller efficiency multiplied by the cost of fuel and divided by the boiler efficiency: Assuming a heat rate of 3500 BTU/kWh (the actual heat rate may be significantly different depending on the current operation of TG1, TG2, and the PRV s), the savings due to increased electrical generation in the turbine-generator is as follows: The cost of fuel associated with the incremental steam load in the HP section of the turbine-generator is as follows: Purdue University 6-35 Burns & McDonnell

129 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Setting the cost to drive an electric chiller equal to the net cost to drive a steam chiller and then rearranging the equation yields the break-even ratio of electricity price to fuel price: Therefore when the price of electricity (in $/MWh) is more than 13.9 times the price of fuel (in $/MMBTU), then it is economically advantageous to dispatch the 125 psig steam chillers instead of an electrically driven chiller. In the chart below, the blue line has a slope equal to 13.9, and represents the break-even ratio. Three different costs of fuel are shown on the chart: $3.67/MMBTU for CFB coal (which includes limestone and ash cost), $4.50/MMBTU for Stoker coal (which includes ash cost), and $5.46/MMBTU for natural gas. The break-even electricity prices that correspond to these fuels are also shown: $51.01/MWh for CFB coal, $62.55/MWh for Stoker coal, and $75.89/MWh for natural gas. In addition, three coordinates are shown where the cost of base purchase energy ($34.33/MWh) intersects with the price of each fuel. All three coordinates are below the break-even line, indicating that driving the equipment electrically is advantageous. However, when Purdue is consuming RTP power rather than base purchase power, the cost of electricity will most likely be more than $34.33/MWh. In the chart below, if the cost of electricity was $50/MWh and incremental steam would be sourced from high-sulfur coal, then it would make the most economic sense to dispatch a 125 psig steam chiller rather than an electric chiller. Purdue University 6-36 Burns & McDonnell

130 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Figure 6-13: 125 psig Steam Chillers - Break Even Ratio Dispatch Steam Cost of Electricity ($/MWh) Dispatch Electric CFB Coal Stoker Coal Natural Gas Cost of Fuel ($/MMBTU) The following example may provide some insight into the practical implementation of the equations above. Suppose, hypothetically, that the campus chilled water demand suddenly increased by 2000 tons. In order to meet this demand, 2000 tons must be produced using either a steam-driven chiller or an electric chiller. Assuming an electric chiller with an efficiency of 0.55 kw/ton would use RTP power at $45/MWh, the cost to supply the 2000 tons with an electric chiller would be $49.50/hour. Assuming a steam-driven chiller with an efficiency of 8700 BTU/(Ton-hr) would use steam sourced from an 86% efficient stoker boiler burning low-sulfur coal priced at $4.30/MMBTU, the cost to supply the 2000 tons with a steam-driven chiller would be $87.00/hour. It appears that dispatching an electric chiller would save $37.50/hour, however, this does not account for the increase in TG electric generation due to the increase in extraction flow. Extraction flow would increase by roughly 15,000 lb/hr, which would increase TG electricity production by about 506 kw and increase boiler steam load by roughly 1.8 MMBTU/hr. Assuming the 506 kw displaces RTP purchases, this would save $23/hour in RTP energy Purdue University 6-37 Burns & McDonnell

131 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling costs, and the 1.8 MMBTU/hr increase in steam load would cost $9/hour. Therefore dispatching the electric chiller would actually only save about $24/hour Chilled Water Production Curtailment Current Capability Chilled water is currently generated in two facilities. The Wade Utility Plant, located on the southern part of campus, houses 6 chillers totaling 22,750 tons of capacity utilizing both steam and electric drives. The NW Chiller plant was added in 2002 and is currently equipped with 5 electric chillers totaling 11,400 tons with a new 2,700 ton electric chiller due to be on line in The table below summarizes the current chiller information. Table 6-11: Existing Chillers Chiller Capacity Install. Retire Driver Location Mfr. Number (Tons) Date Date * Electric NW Chiller Plant 2002 Trane Electric NW Chiller Plant 2002 Trane Electric NW Chiller Plant 2005 Trane Electric NW Chiller Plant 2007 Trane Electric NW Chiller Plant 2007 Trane Steam Wade 1971 Carrier Steam Wade 1988 York Steam Wade 1994 Carrier Electric Wade 1999 Trane Electric Wade 2000 Trane Steam Wade 2001 York 2031 * 30 years is longer than the ASHRAE recommended replacement Curtailment Curtailment with regard to the chilled water system manifests itself in two ways. The current building control sequence utilizing chilled water return temperature control as well as demand reduction procedures to reduce the chilled water demand of the buildings is what most people consider curtailment. However a second condition is related to curtailment and that is the limited condenser water capability in the Wade Utility Plant during the peak hours of the summer. The demand side curtailment of the chilled water system is the result of utilizing chilled water return temperature to control AHU coil flow in the buildings where this sequence is in operation. It has also resulted in space conditions uncomfortable for the building occupants. The implementation of discharge Purdue University 6-38 Burns & McDonnell

132 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling air temperature control will improve space temperature control and increase chilled water usage. Other ECM s, if implemented as discussed in Section 3.0, will potentially reduce the load on the chilled water system. The change of the chilled water usage will vary from building to building. The overall impact of these modifications on the chilled water system cannot be determined at this time. In order to position the chilled water production system to maintain adequate capacity, the chilled water map was calculated utilizing an N+2 approach at the system level. This means the analysis is based on the largest two chillers being out of service. As Purdue transitions to smaller chillers, this will result in a reduced level of reserve capacity as the plant asset mix transitions. Building level demand reduction or curtailment sequences have been instituted over a long period of time due to perceived limitations in the cooling tower capacity at the Wade Utility Plant. The installed cooling tower capacity provides cooling for condensing the steam exiting the Turbine Generator (TG1), the turbine drives for Chillers 6, 7, 8, and 11, and provides refrigerant condensing cooling for all six chillers installed at the Wade Utility Plant. The table below is a list of peak loads served by the six cooling towers and pumps installed at the plant. The chiller steam drive condensing loads are based on 8 lbs/hr of steam for each ton of chilled water production. Table 6-12: Wade Utility Plant Cooling Tower Loads Load Description Tower Load (tons) Closed Cooling Water 1,000 Gland Seal Condensers 1,000 Miscellaneous 200 Chiller 6 Refrigerant Condenser 6,250 Chiller 6 Steam Condenser 3,863 Chiller 7 Refrigerant Condenser 3,000 Chiller 7 Steam Condenser 1,854 Chiller 8 Refrigerant Condenser 4,500 Chiller 8 Steam Condenser 2,781 Chiller 9 Refrigerant Condenser 2,500 Chiller 10 Refrigerant Condenser 2,500 Chiller 11 Refrigerant Condenser 5,000 Chiller 11 Steam Condenser 3,090 Steam Turbine Generator Condenser (TG1- Full Condensing) 19,313 Total Peak Tower Demand 56,850 There are currently six cooling tower cells and circulating water pumps installed outdoor south of the Wade Utility Plant near the coal storage. The table below lists the relevant design data for each cell and pump. Purdue University 6-39 Burns & McDonnell

133 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Table 6-13: Cooling Tower Design Capacity Asset Metric Units Value Number of Cells No. 6 Design Hot Water Temperature F 101 Design Cold Water Temperature F 85 Design Wet Bulb Temperature F 77 Design Flow per Cell gpm 15,000 Design Load per Cell Tons 10,000 Total Peak Tower Capacity Tons 60,000 The tables above illustrate that the available capacity installed is sufficient to meet all required loads during a design day. However, these calculations assume that the pumps, towers, and heat exchangers are in new condition and are operating according to their designed intent. There are several key factors that could influence the overall capacity available from the cooling system. They are as follows: 1. The cooling towers are not capable of providing design capacity. This may be due to one or more of the following issues: a. The tower fill is fouled through particulate or biological contamination b. The tower nozzles are plugged and are not providing sufficient water dispersion for design evaporative cooling. c. The fans are not moving enough air due to fan pitch, increased tower pressure drop, or other obstructions. 2. The pumps are not providing enough flow for the tower design rating. This may be due to one or more of the following issues: a. Impeller erosion/corrosion due to chemical or particulate basin contamination and preventative maintenance. b. The inlet head available to the pump may be insufficient due to low basin levels or increased suction pressure drop due to plugged inlet screens. c. The system may have larger pressure drop than anticipated during design due to fouling, system modifications, or increases in heat exchanger pressure drop. This will cause the pump to provide less flow than desired. 3. The system heat exchangers and condensers are fouled. Fouling will decrease the system return temperature and reduce tower capacity. Fouling or pluggage will also cause the system curve to shift and reduce the overall pump capacity. Purdue University 6-40 Burns & McDonnell

134 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Purdue University staff also indicated that the circulating water pumps are being rewound at a regular interval due to damage caused by overloading the motors. According to the curve below, the installed 400hp motors are already operating above their designed rating. Figure 6-14: Cooling Water Pump Curve Continuous operation above the design point causes motor overheating and premature failure. Although a service factor is provided to allow motors to operate above design ratings, it is intended for short periods of time to allow for system disruptions and start-up conditions without significantly impacting motor life. Larger motors would eliminate this recurring expense and provide a cost effective solution to this problem. A careful study of the available cable size and voltage available is necessary prior to increasing the motor size. Limits in cable size may be eliminated by running a new conduit parallel to the existing conveying system. The figure above also demonstrates the affect that decreases in suction pressure, increases in system pressure drop, or pump impeller degradation may have on the flow provided by each pump. Each of these conditions will either change the intersection of the system and pump curves or directly reduce the pump Purdue University 6-41 Burns & McDonnell

135 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling capacity resulting in reduced flow to towers. The effect of having a cell out of service due to motor issues and/or having a significant reduction in flow is illustrated in the figure below. Figure 6-15: Cooling Tower Capacity 60,000 Tons 50,000 40,000 30,000 6 Cells, 90% Rated Flow 5 Cells, 100% Rated Flow 6 Cells, 80% Rated Flow 5 Cells, 90% Rated Flow 5 Cells, 80% Rated Flow Peak Cooling Tower Load 20,000 10,000 0 CCW SSF Misc Chiller 7 Chiller Chiller 7 Cond Chiller 8 Chiller Chiller 8 Cond Chiller 9 Chiller Chiller 10 Chiller Chiller 11 Chiller Chiller 11 Cond Steam Turbine Chiller 6 Chiller Chiller 6 Cond Regardless of the existing capacity limitations, by limiting the amount of steam condensed in TG1, a significant amount of capacity can be allocated to chilled water loads and reduce or eliminate the need for curtailment. The decision to limit the amount of steam in TG1 will force the University to purchase more power from the local electrical utility. Power from the utility during the summer cooling season when tower demand is the highest is expensive. The cost for additional steam production to generate additional electricity through the condensing turbine is typically more cost effective. Average costs for providing electricity to campus during peak cooling season are provided below. Table 6-14: Curtailment Electricity Costs Average Cost to Purchase Real Time Power from Average Cost to Produce Incremental Electricity the Utility with Existing Boiler Capacity through TG1 $66/MWh $45/MWh These costs are based on the following key assumptions: Purdue University 6-42 Burns & McDonnell

136 Comprehensive Energy Master Plan FINAL DRAFT 6.0 Production Modeling Analysis utilized existing dispatch model developed as part of the Level II Combined Heat and Power Analysis to determine average cost to produce incremental steam for condensing in TG1. Cost of Electricity is assessed for the times of year where there may not be enough tower capacity to supply all potential loads. The time frame is defined as follows: o June, July and August o Monday Friday o 8am to 8pm According to the dispatch previously developed and utilizing existing assets, in 2011 it was advantageous to incrementally dispatch TG1 above that needed to meet thermal loads during the time frame outlined above. During this time frame the analysis recommended producing an additional 12,500 MWh s instead of purchasing this power from the utility. Applying the $21/MWh difference in the cost to produce and purchase this power as outlined above, the opportunity cost to not produce this power is approximately $265,000 per year. This potential annual savings is sufficient to fund a myriad of system improvement projects up to and potentially including the installation of additional cooling tower capacity. However, several steps must be taken to determine to optimum system investment. 1. Develop a hydraulic and thermodynamic model of the cooling water system to determine the pressure drop in the existing system and the interaction with the existing pumps. 2. Perform a detailed inspection of at least two of the pumps to determine screen pluggage and potential impeller degradation. 3. Commission a performance test for the cooling towers and pumps to determine current capacity. 4. Inspect and clean condensers and heat exchangers. 5. Calibrate hydraulic model to account for known conditions. 6. Investigate barriers to increasing the pump motor size. The available annual savings listed above is sufficient to fund the items outlined above. Once the condition of the existing assets is known recommendations can be made to either remediate existing assets or add additional cooling capacity. * * * * * Purdue University 6-43 Burns & McDonnell

137 Comprehensive Energy Master Plan FINAL DRAFT 7.0 Building Interconnection Model 7.0 BUILDING INTERCONNECTION MODEL The tool is designed to determine the cost savings of connecting a building to the campus chilled water and steam distribution network versus utilizing local chilled water and steam generation at the building. The tool has standard input fields represented by blue cells and the calculated values are grey cells. All inputs and calculations on the main page and all subsequent pages can be changed or edited by the user. 7.1 APPROACH Determining the Load The load is calculated based on the size and type of the facility. Each type of facility available in the database is associated with a heating load and cooling load per square foot. The user has the option to add additional process loads to both the heating and cooling load. These projected heating and cooling loads are used as the basis of the analysis depending on the efficiencies and diversities of the respective scenario. Based on the actual anticipated building use the equivalent full load heating and cooling hours may need to be adjusted in the data tab Generation of Energy from District System The cost to generate steam at the central plant is determined by the efficiency of the boilers and the cost of natural gas as well as low and high sulfur coal. The cost of fuel is divided among the steam load based on the MMBtu s created by each fuel type. This cost is equated to a per pound of steam basis according to the steam enthalpy differential in the campus distribution loop. An additional load is added to the total peak heating load required at the facility to account for the distribution losses. The annual heating equivalent full load hours is applied to the total peak heating load to yield an annual pounds of steam generated. This is multiplied by the cost to generate steam from the district system to yield an annual cost of energy for the steam system. The cost to generate chilled water at the central plant is based on the costs to operate the chilled water equipment. The cost to operate the electrical centrifugal and the steam chillers are combined based on a weighted average based on the ton hours of the respected chillers and the cost of electricity and the cost to generate steam. Also included in this number, is the cost to operate the cooling towers and the associated pumps. As chilled water generation schemes and utility costs change, this number should be refined. An additional load is added to the total building peak cooling load to account for the distribution losses. The annual cooling equivalent full load hours is applied to the total peak cooling load to yield the Ton-Hrs Purdue University 7-1 Burns & McDonnell

138 Comprehensive Energy Master Plan FINAL DRAFT 7.0 Building Interconnection Model required to be generated at the central plant. This is multiplied by the cost to create chilled water from the district system to give an annual cost of energy for the chilled water system Local Generation of Energy Local generation of chilled water uses the chilled water plant efficiency (IPLV) which accounts for all of the local chilled water generating equipment including the centrifugal chiller, pumps and cooling towers. This efficiency is multiplied by both the firm capacity of the local chilled water plant and the annual cooling equivalent full load hours to yield the annual kwh. The electric rate is applied to the annual kwh to yield the annual cost of electricity for the local chilled water plant. The cost for local generation of steam is determined by the firm capacity of the local steam plant multiplied by the annual heating equivalent full load hours, the cost of natural gas, and the efficiency of the local boiler Capital Costs The capital cost for the expansion of the district steam plant is determined by the total peak heating load multiplied by a cost per pound per hour of steam expansion that accounts for iterative expansion of all equipment necessary to generate steam. The capital cost for expansion of chilled water equipment for the district system is determined by the total diversified peak cooling load multiplied by a cost per ton of chilled water equipment expansion that accounts for iterative expansion of all equipment necessary to generate chilled water at the district system. The capital cost for the local generation is dependent on the size and number of boilers and chillers selected. The load is divided among the number of boilers and the redundancy requirement selected. The capacity of the total number of boilers is multiplied by the respective cost per unit of capacity to install a local boiler and chiller plant. The distribution line sizes are based on velocities input by the user. Steam line sizes are based on the distribution pressure selected by the user. Schedule 40 pipe is default for chilled water and steam lines. Schedule 80 is used for condensate lines. The cost of the distribution piping is based on the trench distance from the distribution network input by the user. The cost is based on the size of the line and includes pipe, excavation and backfill, and two valves for each line. These costs should be kept up to date with actual installed data. The user chooses a multiplier for the distribution costs based on the difficulty Purdue University 7-2 Burns & McDonnell

139 Comprehensive Energy Master Plan FINAL DRAFT 7.0 Building Interconnection Model and congestion of the proposed routing path. The capital construction project costs incorporate a contingency represented as a percentage of the overall project cost Annually Recurring Costs Annually recurring costs are utility costs, including natural gas and electricity, as well as required operation and maintenance Utility Costs The electric rate includes all base purchase and real time power charges from Duke Energy. The natural gas rate includes the Henry Hub gas rate plus an assumed delivery charge of $1.00/MMBtu Life Cycle Cost Analysis The capital costs are treated as cost paid in cash in the year chosen for the project to be implemented. Annually recurring costs are considered in the analysis and are escalated based on their respective escalation rates, as input by the user, throughout the duration of the life cycle cost analysis, starting with the project implementation year. The net present value (NPV) for each project is calculated based on today s dollars. Savings is shown as NPV of the savings for connecting the building to the distribution network versus utilizing local generation, throughout the life of the project. A negative total savings value indicates that connecting the building to the distribution network will not payback over the life of the project Results It should be noted that specific pumping and distribution impacts are not included and should be reviewed separately utilizing the campus flow models. This tool enables the university to quickly develop an order of magnitude cost impact of connecting a building to the distribution system compared to utilizing assets installed at the building. It is intended for general guidance but provides a solid go/no-go for facility systems determination. Purdue University 7-3 Burns & McDonnell

140 Comprehensive Energy Master Plan FINAL DRAFT 7.0 Building Interconnection Model Table 7-1: Building Connection Evaluation Example Project Name: EXAMPLE Date: 10/5/2011 Cost for Connection to District Plant (PV) $5,040, YEAR DISTRICT CAPITAL COST SAVINGS V/S LOCAL (PV): ($20,253) Cost for Local Production (PV) $5,978, YEAR DISTRICT MAINTANENCE COST SAVINGS V/S LOCAL (PV): $527,452 Total District Savings v/s Local (PV) $938, YEAR DISTRICT ENERGY COST SAVINGS V/S LOCAL (PV): $431,378 GENERAL FINANCIAL FACTORS ESCALATION RATES Discount Rate 3.5% Operations & Maintenance 3.0% General Inflation Rate 3.0% Natural Gas 4.0% Capital Contingency 0.0% Electricity 3.0% FACILITY DESCRIPTION PURCHASED UTILITY COST CURRENT YEAR Facility Size 150,000 Sq. Ft. Natural Gas Cost $5.010 /MMBtu Facility Type CLASS/OFFICE Electricity $0.056 /kwh Year Project Complete 2014 TRENCH DISTANCE FROM DISTRIBUTION NETWORK 100 FT ROUTING DIFFICULTY NORMAL Projected Peak Heating Load 3150 MBH Projected Peak Cooling Load 429 Tons Enter Additional Process Steam Load PPH Enter Additional Cooling Load Tons Annual Heating Equivalent Full Load Hours 3,782 Annual Cooling Equivalent Full Load Hours 3,413 See below for Override. Note that selecting override will not account for diversity or distribution losses. Building Connection Evaluation See below for Override. Note that selecting override will not account for distribution losses. Note: Local production will require additional building space. This dollar value is not represented in this analysis. STEAM FACTORS CHILLED WATER FACTORS Local Generation Select Local Steam Pressure 55 Local CHW Plant Efficiency (IPLV) 0.85 kw / Ton Steam Enthalpy Differential (Bldg) BTU/LB Local HHV Boiler Efficiency 78% District Generation Cost to Generate Steam at Distric System $4.01 /MMBtu Chilled Water Temp Differential 14 deg F Steam Enthalpy Differential (Campus) 1163 BTU/LB District CHW Load Diversity 80% District Steam Plant Production Cost $4.66 /klb District CHW Production Cost $0.04 /Ton Hr District Steam Distribution Losses 8% District CHW Distribution Losses 3% Notes: Campus Enthalpy Differential is a blended value between 125 psig and 15 psig LOCAL GENERATION VARIABLES Steam Service Chilled Water Service Redundancy Requirement NONE Redundancy Requirement N+1 Total Number Of Boilers 3 Total Number Of Chillers 3 Capacity Per Boiler 998 PPH Capacity Per Chiller 214 TONS Recommended Total Capacity 2,994 PPH Recommended Total Capacity 643 TONS Capacity Overide? FALSE Yes Capacity Overide? FALSE Yes Enter Overide Total Boiler Capacity 2,500 Enter Overide Total Chilled Water Capacity 2,400 Steam System Capital Cost $194,622 Chilled Water System Capital Cost $1,285,714 DISTRICT SYSTEM VARIABLES Steam Service Chilled Water Service Projected Peak Heating Load 3,234 PPH Projected Peak Cooling Load 441 TONS Overide Peak Heating Load? FALSE Yes Overide Peak Cooling Load? FALSE Yes Enter Overide Peak Heating Load 2,400 Enter Overide Peak Cooling Load 367 Total Peak Heating Load 3,234 PPH Total Peak Cooling Load 441 TONS Choose Steam Distribution Pressure 125 Enter Max CHW Velocity 8 Ft/sec Enter Max Steam Velocity Ft/min Recommended CHW Lines Size 8 " Recommended Steam Lines Size 2 " Plant Expansion Cost $882,857 Recommended Condensate Line Size 1 " CHW Distribution System Cost $48,000 Plant Expansion Cost $242,529 Steam Distribution System Cost $327,500 * * * * * Purdue University 7-4 Burns & McDonnell

141 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling 8.0 DISTRIBUTION MODELING Modeling of the steam and chilled water distribution systems at Purdue was performed with the goal of identifying pressure and velocity issues in the system under current operating conditions as well as future operating conditions. The model allowed several distribution improvement options to be evaluated based on how they alleviated the issues that had been identified. 8.1 STEAM Purdue operates two different pressure distribution systems to distribute steam to the buildings on campus. One system is 15 psig which serves the majority of the heating loads, and the other is 125 psig which serves process loads as well as supplements the 15 psig system via pressure reducing stations. This allows the 125 psig system to indirectly serve all of the loads served by the 15 psig system, providing the campus with some redundancy in their distribution system Load Definition Steam load information was provided by Purdue University for existing buildings. Because peak steam usage information is not available via meters at the building level, loads provided were estimated on a BTU/SF basis depending on space usage type. The total building loads match fairly closely to historical steam production distributed from the plant. Therefore the building loads provided are assumed to be an accurate representation of the diversified peak campus steam load. Loads provided for future buildings were estimated in a similar BTU/SF fashion, depending on occupancy type. Future building loads were added to the distribution model in the appropriate location and used to establish a five year diversified peak load. A summary of these buildings can be seen in Table 8-4. Other future loads were added to the distribution system in locations in which the campus expects to see future growth, but were not necessarily specific locations, in order to define the 20 year diversified peak. This peak was based on overall forecasts provided as part of the Level II Combined Heat and Power Study. Steam flow summary information for each of the three load cases can be seen in Table 8-1, Table 8-2 and Table 8-3 below. Purdue University 8-1 Burns & McDonnell

142 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Table 8-1: Current Peak Wade Utility Plant Summary Pipe From Wade Pipe Size Steam Flow Velocity (in) (lb/hr) (ft/sec) 125 psig line # , psig line # , psig 18 74, Total - 367,176 - Table 8-2: 5 Year Peak Wade Utility Plant Summary Pipe From Wade Pipe Size Steam Flow Velocity (in) (lb/hr) (ft/sec) 125 psig line # , psig line # , psig 18 74, Total - 383,182 - Table 8-3: 20 Year Peak Wade Utility Plant Summary Pipe From Wade Pipe Size Steam Flow Velocity (in) (lb/hr) (ft/sec) 125 psig line # , psig line # , psig , Total - 530,228 - Table 8-4: 5 Year Building Addition Summary Building Addition Load (lb/hr) Health and Human Sciences 4,420 Drug Discovery 5,360 Herrick Lab 4,060 Bindley Addition 2,560 Service Building Removal -305 Service Building Annex Removal -88 Total 16,008 Purdue University 8-2 Burns & McDonnell

143 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Approach The aforementioned loads, as well as GIS data provided by the University was used to build a model of the steam distribution system in Applied Flow Technology s (AFT s) software for compressible fluid flow, Arrow. Other assumptions used in the model are listed below: Wade plant distributes steam at 125 psig, 525 F and 15 psig, 325 F. Piping lengths were obtained by dimensioning the GIS AutoCAD file. Only horizontal distances were used i.e. the extra length due to the slope of the pipe was not included. 90 degree bends were included with an r/d ratio of 1.5. Valves were included as 100% open gate valves with a k value of 0.2. Piping was assumed to be STD schedule. Piping was modeled as steel with an absolute roughness of inches. 10 piping to Mackey Arena was increased to 16 in order to reduce the velocity enough to compute results. 4 piping to Neil Armstrong Hall of Engineering was increased to 10 in order to reduce the velocity enough to compute results. Tee junctions were treated as zero losspoints to reduce complexity and computation time. Once all the information was input into the model, it was computed and the initial results were compared to distribution system readings provided by Purdue. The readings on February 10, 2011 at 8:00am were used for calibration, as this was the highest total steam flow from the Wade Utility Plant in the readings provided. A summary of the calibration results can be seen in Table 8-5. Calibration efforts concluded with 4 out of the 5 readings being within 6% of actual readings. Because the velocity in the header near Forney is so high, and therefore the pressure drop is so high, the pressure reading in Forney is very sensitive to the location the measurement is taken. This offers one explanation for the margin of error in this reading. It is also possible that the pressure gauge/transmitter at Forney needs to be calibrated. Table 8-5: Calibration Results Reference Point Actual Pressure Model Pressure (psig) (psig) PA Pit Forney Disk Park Vawter Third Street Purdue University 8-3 Burns & McDonnell

144 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Industry standards consider velocities in a steam system above 150 ft/sec to be undesirable, and velocities above 200 ft/sec to be extreme. Acceptable steam pressure is relative to existing control valve capacities and process steam pressure requirements. It was assumed current operating conditions (65.9 psig actual/63 psig modeled pressure at PA Pit) provide sufficient pressure for campus steam needs. For cases where pressure drops below this at PA Pit it was assumed the distribution system would no longer be able to meet campus steam demands Results A summary of steam flows from the Wade Utility Plant can be seen for each scenario below in Table 8-1, Table 8-2 and Table 8-3. The results of the model were evaluated to identify areas of high velocity and high pressure drop in the system under current peak operating conditions and under future peak operating conditions. Figure 8-1 and Figure 8-2 below illustrate the pressure in the system at peak steam flow under the current peak operating scenario. Notice the pressure in the high pressure system reduces as it extends away from the plant, and that the majority of the low pressure system registers at or below 10 psig. Figure 8-3 shows velocities in the system at this steam flow. Figure 8-4, Figure 8-5 and Figure 8-6 show the distribution system pressures and velocities in the 5 year scenario. Purdue University 8-4 Burns & McDonnell

145 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-1: Base Case High-Pressure System Pressures Purdue University 8-5 Burns & McDonnell

146 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-2: Base Case Low-Pressure System Pressures Purdue University 8-6 Burns & McDonnell

147 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-3: Base Case Velocity WADE Purdue University 8-7 Burns & McDonnell

148 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-4: 5 Year Scenario High-Pressure System Pressures Purdue University 8-8 Burns & McDonnell

149 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-5: 5 Year Scenario Low-Pressure System Pressures Purdue University 8-9 Burns & McDonnell

150 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-6: 5 Year Scenario Velocity WADE Purdue University 8-10 Burns & McDonnell

151 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling For the 20 year scenario, forecasted load growth was added to the system in the form of 8 arbitrary buildings. Each building accounts for 1/8 of the projected peak steam load growth. The buildings were input into the model in locations in which the campus anticipates growth in the future, namely near the service building and food stores building at the south end of campus and the central northern area which the campus does not currently own. This scenario resulted in pressure drops and velocities so high that in order to obtain results, the pipe size for the northeast run from ME to LAMB had to be increased to 12. The pressure and velocity results for the 20 year scenario, after the pipe modification, can be seen in Figure 8-7, Figure 8-8 and Figure 8-9. This scenario indicates that the campus distribution system will have extreme velocities in many locations, and will likely not be able to sustain steam flow to meet campus demands. Additional, substantial modifications will be required to supply the campus peak steam demand. Purdue University 8-11 Burns & McDonnell

152 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-7: 20 Year Scenario High-Pressure System Pressures NEW BUILDING Purdue University 8-12 Burns & McDonnell

153 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-8: 20 Year Scenario Low Pressure System Pressures Purdue University 8-13 Burns & McDonnell

154 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-9: 20 Year Scenario Velocity NEW BUILDING WADE Purdue University 8-14 Burns & McDonnell

155 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Distribution Improvement Scenarios As seen in the figures above, there are some high velocity areas in the distribution system both in the current case and in the five year case. Also in the current case and especially in the 5 year case pressure at the north end of campus becomes a concern. Several distribution improvement scenarios were analyzed to alleviate areas of high velocity and improve the pressure available at the north end of campus during peak steam flows. The scenarios analyzed are described below. New 8 pipe run from Third Street to PA Pit. This option provides a third path for steam to reach the north end of campus and relieves flow from the east and west runs that currently have high velocities. Figure 8-10, Figure 8-11 and Figure 8-12 show the results of this scenario. Increase pipe size in Jischke Drive from 6 to 12 from Third Street to Tower Drive. This also includes the pipe from north of Vawter to Jischke Drive. This option reduces velocities and pressure drop in the Jischke drive pipe and shifts some flow from the NE run, reducing velocity and pressure drop in that pipe. Figure 8-13, Figure 8-14 and Figure 8-15 show the results of this scenario. Increase pipe size in NE campus from 8 to 12 from ME to LAMB. This option reduces velocities and pressure drop in the NE run and shifts some flow from the Jischke Drive run, reducing velocity and pressure drop in that pipe. Figure 8-16, Figure 8-17 and Figure 8-18 show the results of this scenario. Note that the increase in pipe size to 12 in the NE portion of campus was modeled for the 20 year case. Prior to including this improvement, velocities and pressure drops were so high, the model failed to compute. Again, even with this improvement, velocities and system pressures are unacceptable in the 20 year case. Purdue University 8-15 Burns & McDonnell

156 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-10: Third Street to PA Pit High-Pressure System Pressures Purdue University 8-16 Burns & McDonnell

157 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-11: Third Street to PA Pit Low-Pressure System Pressures Purdue University 8-17 Burns & McDonnell

158 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-12: Third Street to PA Pit Velocity WADE Purdue University 8-18 Burns & McDonnell

159 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-13: Jischke Pipe Upsize High-Pressure System Pressures Purdue University 8-19 Burns & McDonnell

160 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-14: Jischke Pipe Upsize Low-Pressure System Pressures Purdue University 8-20 Burns & McDonnell

161 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-15: Jischke Pipe Upsize Velocity WADE Purdue University 8-21 Burns & McDonnell

162 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-16: NE Upsize High-Pressure System Pressures Purdue University 8-22 Burns & McDonnell

163 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-17: NE Upsize Low-Pressure System Pressures Purdue University 8-23 Burns & McDonnell

164 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-18: NE Upsize Velocity WADE Purdue University 8-24 Burns & McDonnell

165 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Conclusions The results of the model indicate that during peak operating conditions in the next 5 years, pressures in the north end of the system will drop below 60 psig. This will limit the capacity of the existing pressure reducing valves and reduces potential for the low pressure system to supply steam to buildings. All recommended distribution system improvement options increase the system pressure at the PA Pit. However, because the piping in the NE corner of campus is undersized by the largest margin, and there is a high concentration of high load buildings in that area, upsizing the piping in the NE corner of campus provides the greatest increase in pressure and room for load growth in the future. The complexity required to upgrade this line is significant. Due to this and upgrades already planned and being executed on Jischke Drive it is recommended that this upgrade be executed first. Careful consideration should also be given to the installation of a new line from Third Street to PA Pit. This will provide viable source for new loads added in the central portion of campus north of Third Street. A summary of project costs and the pressure increase at the PA pit can be seen in Table 8-6 below. Table 8-6: Improvement Option Summary Construction Cost PA Pit Pressure PA Pit Scenario $ (psig) (psi) 5 Year Third Street to PA Pit $1,700, Jischke Drive Upsize $1,500, NE Pipe Upsize $1,900, Several branch connections to buildings were found to be undersized based on the loads provided for these building. It is recommended that the loads for these buildings be verified. Although high velocities in these branch lines do not have a significant effect on the rest of the distribution system, pipe erosion and increased damage potential from water hammer are reasons to evaluate these lines. A summary of these branch lines can be found in Table 8-7 below. All values are based on the 5 year scenario model results. All the options above were evaluated to prevent pressure degradation sufficient to address 5 year distribution capacity deficiencies. To address long term deficiencies significant new north/south capacity will need to be installed or a distributed steam plant will need to be installed. The best solution should be re-evaluated over the next 5-10 years based on the impact of ECM implementation and revisions in projected load growth. Purdue University 8-25 Burns & McDonnell

166 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Building Branch Table 8-7: Branch Line Summary Pipe Size Steam Flow Velocity (in) (lb/hr) (ft/sec) Neil Armstrong Hall of Engineering 4 8, * Guy J. Mackey Arena 10 16, * Physics N 6 7, Physics C 6 7, Physics S 4 3, Recreational Sports Center 6 13, Eleanor B. Shreve Residence Hall 1-1/4 1, Lilly Hall 10 28, Lynn East 6 10, Lynn West 6 10, *Local branch to building pipe size was increased in model in order to compute results. Velocity calculated based on actual pipe size, mass flow rate, and density. 8.2 CHILLED WATER The chilled water system at Purdue is supported by two plants. A large portion of the chilled water load is generated at the Wade Utility Plant. The Northwest Satellite Plant supports the system by supplying load and by providing additional pressure in the pipelines farther away from Wade. Many of the buildings on campus use booster pumps at their connections to the chilled water system to ensure that there is sufficient pressure to supply water to the building Load Definition Peak load data for existing buildings was provided by Purdue University. Loads for buildings that were not provided were estimated in terms of Tons/SF depending on space usage type. Loads provided for future buildings were also estimated based on Tons/SF depending on space occupancy type. As with the steam model, future buildings whose exact location was known were placed into the model accordingly and used to establish 5-year diversified peak load. A summary of these buildings can be found in Table The remaining future loads were added to the model in general areas which are expected to see future growth to define a 20-year diversified peak. This total peak was based on overall forecasts provided as part of the Level II Combined Heat and Power Study. Purdue University 8-26 Burns & McDonnell

167 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling A summary of the chilled water flows from all three scenarios can be found in Table 8-8, Table 8-9, and Table 8-10 below. Plant Table 8-8: Base Case Chilled Water Summary Pipe Size Produced Flow Velocity Leaving Plant (in) (gal/min) (ft/sec) Wade 36 23, NW Satellite 24 23, Total - 47,600 - Plant Table 8-9: 5-Year Scenario Chilled Water Summary Pipe Size Produced Flow Velocity Leaving Plant (in) (gal/min) (ft/sec) Wade 36 24, NW Satellite 24 24, Total - 48,700 - Plant Table 8-10: 20-Year Scenario Chilled Water Summary Pipe Size Produced Flow Velocity Leaving Plant (in) (gal/min) (ft/sec) Wade 36 26, NW Satellite 24 25, Satellite II 32 16, Total - 67,800 - Velocities greater than 10 feet/second are acceptable if the annual hours above that velocity are less than 1500 hours per year. However, velocities above 15 feet/second are considered unacceptable regardless of operating hours. Table 8-11: 5-Year Building Addition Summary Building Addition Load (tons) Health and Human Sciences 334 Drug Discovery 404 Herrick Lab 306 Bindley Addition 192 Total 1,236 Purdue University 8-27 Burns & McDonnell

168 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Approach The aforementioned chilled water loads, as well as GIS data provided by Purdue University, were used to build a distribution system model in AFT s incompressible fluid flow software, Fathom. Pipe lengths, sizes, and fittings were input into the model based on the given GIS data. Purdue also provided performance curves for the primary and secondary chilled water pumps that were utilized in the model to represent plant output under changing conditions. The arrangement of utility plant components (chillers, pumps, control valves, etc.) were modeled according to schematic drawings provided by Purdue. Other assumptions input into the model are listed below: Wade and the NW Plant produce chilled water at 48 F The change in temperature of the system was assumed to be F Pipe lengths were obtained by dimensioning the GIS and AutoCAD file. Only horizontal distances were used i.e. the extra length due to the slope of the pipe was not included. 90 degree bends were included with an r/d ratio of 1.5. All valves were assumed to be 100% open butterfly valves with a K value of Piping was assumed to be STD schedule. Piping was modeled as steel with an absolute roughness of inches. Tee junctions were assumed to carry no friction losses to reduce complexity and computation time. The modeling software used the data given to calculate fluid velocities and differential pressures within the piping system. The model was then calibrated by comparing initial results of these calculations to distribution system readings provided by the University. These readings monitored the pressure drop across four buildings scattered across Stewart Center, Biochemistry Building, Morgan Center for Entrepreneurship, and Heine Pharmacy Building, as well as the total system flow rate over the course of one month. These measurements were compared to their corresponding results from the distribution model. Figure 8-19, Figure 8-20, and Figure 8-21 illustrate the comparison of the actual system performance data and the model results. Three out of the four buildings from the model showed differential pressures that fell within the range of measurements taken from the system readings. Therefore, the model was considered to be an acceptable replication of the chilled water distribution system. The fourth building showed a large discrepancy. This may be due to transmitter accuracy, location, or variability in the load at that building when measured compared to the load modeled. Purdue University 8-28 Burns & McDonnell

169 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Long term capacity additions are located at the north end of campus. Due to the limitations of the existing distribution system, adding chilled water capacity at Wade is not a viable option and would exacerbate existing challenges in the north-east corner of campus and significantly increase the chilled water velocities leaving Wade. Figure 8-19: Biochemistry Building Calibration Chart Purdue University 8-29 Burns & McDonnell

170 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-20: Heine Pharmacy Calibration Chart Purdue University 8-30 Burns & McDonnell

171 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-21: Burton Morgan Center Calibration Chart Stewart Center was the one outlier in the calibration. The reason for this is likely tied to the fact that Stewart is one of several buildings in the model that exhibted excessively high chilled water inlet and outlet velocities. These high velocities likely skewed the results of Stewart Center s calibration. Suggestions for addressing Stewart and other problem areas will be discussed in the Conclusions section of this portion of the report Results The results of the model were evaluated to determine areas of high velocity and low differential pressure in the system. Figure 8-22, Figure 8-23, Figure 8-24 and Figure 8-25 shows the differential pressures in the system at peak flow under the current operating scenario. Figure 8-26 shows the fluid velocities in the piping at peak flow. Figure 8-27, Figure 8-28, Figure 8-29 and Figure 8-30 illustrate the system pressure drop of the 5-year model. Figure 8-31 shows the chilled water pipeline velocities. Purdue University 8-31 Burns & McDonnell

172 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-22: Base Case System Pressures, NE Quadrant Purdue University 8-32 Burns & McDonnell

173 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-23: Base Case System Pressures, NW Quadrant Purdue University 8-33 Burns & McDonnell

174 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-24: Base Case System Pressures, SW Quadrant Purdue University 8-34 Burns & McDonnell

175 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-25: Base Case System Pressures, SE Quadrant Purdue University 8-35 Burns & McDonnell

176 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-26: Base Case System Velocities Purdue University 8-36 Burns & McDonnell

177 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-27: 5-Year Scenario Pressures, NE Quadrant Purdue University 8-37 Burns & McDonnell

178 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-28: 5-Year Scenario Pressures, NW Quadrant Purdue University 8-38 Burns & McDonnell

179 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-29: 5-Year Scenario Pressures, SW Quadrant Purdue University 8-39 Burns & McDonnell

180 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-30: 5-Year Scenario Pressures, SE Quadrant Purdue University 8-40 Burns & McDonnell

181 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-31: 5-Year Scenario Velocities Purdue University 8-41 Burns & McDonnell

182 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling As with the steam distribution model, forecasted load growth for the 20-year scenario was added to the system in the form of 8 arbitrary buildings. These buildings were placed in the two areas where the University expects to see future growth: the two service buildings on the south side of campus along Service Drive and the central northern area which is not currently owned by the University. The pressure drop problems in the northeast part of campus became so severe that a new satellite utility plant was added to the model to relieve these issues. Pressure and velocity profiles for the 20-year scenario can be found in Figure 8-32, Figure 8-33, Figure 8-34, Figure 8-35 and Figure 8-36 below. Purdue University 8-42 Burns & McDonnell

183 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-32: 20-Year Scenario Pressures, NE Quadrant Purdue University 8-43 Burns & McDonnell

184 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-33: 20-Year Scenario Pressures, NW Quadrant Purdue University 8-44 Burns & McDonnell

185 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-34: 20-Year Scenario Pressures, SW Quadrant Purdue University 8-45 Burns & McDonnell

186 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-35: 20-Year Scenario Pressures, SE Quadrant Purdue University 8-46 Burns & McDonnell

187 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-36: 20-Year Scenario Velocities Purdue University 8-47 Burns & McDonnell

188 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Distribution Improvement Scenarios The results of the distribution modeling reveal that the northeast area of campus suffers from lack of pressure in the system, requiring that the buildings in this area have booster pumps installed to maintain adequate chilled water flow. This problem extends from the base case to the 5- and 20-Year scenarios. In addition the velocity in the pipe leaving the satellite plant is above 12 ft/s. Several distribution improvement scenarios were investigated to improve the supply pressure in the northeast part of campus. The scenarios analyzed are as follows: Upgrade the secondary pumps in the Northwest Satellite Plant from three 200 hp pumps and two 250 hp pumps to three 250 hp pumps and two 300 hp pumps. This allows the satellite plant to provide more pressure to the distribution system, which results in a higher differential pressure across the buildings in the northeast side of the campus. Figure 8-37, Figure 8-38, Figure 8-39, Figure 8-40 and Figure 8-41 show the effects of this upgrade on the system pressure and velocities. Add a new 18 pipe run to the system that runs along Third Street from south of the Northwest Satellite Plant to the Lawson Computer Science building. This scenario creates a new loop which supplies more pressure directly to the northeast part of campus. Figure 8-42, Figure 8-43, Figure 8-44, Figure 8-45 and Figure 8-46 illustrate the results of this scenario. Add a new satellite chilled water plant to the north end of campus. This plant was modeled to be properly integrated with the performance of the Northwest Plant and still supply enough pressure to the northeast portion of campus to alleviate the high velocities and pressure drops. Figure 8-47, Figure 8-48, Figure 8-49, Figure 8-50 and Figure 8-51 show the results of this scenario. Purdue University 8-48 Burns & McDonnell

189 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-37: NW Plant Pump Upgrade Pressures, NE Quadrant Purdue University 8-49 Burns & McDonnell

190 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-38: NW Plant Pump Upgrade Pressures, NW Quadrant Purdue University 8-50 Burns & McDonnell

191 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-39: NW Plant Pump Upgrade Pressures, SW Quadrant Purdue University 8-51 Burns & McDonnell

192 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-40: NW Plant Pump Upgrade Pressures, SE Quadrant Purdue University 8-52 Burns & McDonnell

193 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-41: NW Plant Pump Upgrade Velocities Purdue University 8-53 Burns & McDonnell

194 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-42: New 18" Pipeline Pressures, NE Quadrant Purdue University 8-54 Burns & McDonnell

195 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-43: New 18" Pipeline Pressures, NW Quadrant Purdue University 8-55 Burns & McDonnell

196 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-44: New 18" Pipeline Pressures, SW Quadrant Purdue University 8-56 Burns & McDonnell

197 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-45: New 18" Pipeline Pressures, SE Quadrant Purdue University 8-57 Burns & McDonnell

198 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-46: New 18" Pipeline Velocities Purdue University 8-58 Burns & McDonnell

199 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-47: New North Sat. Plant Pressures, NE Quadrant Purdue University 8-59 Burns & McDonnell

200 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-48: New North Sat. Plant Pressures, NW Quadrant Purdue University 8-60 Burns & McDonnell

201 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-49: New North Sat. Plant Pressures, SW Quadrant Purdue University 8-61 Burns & McDonnell

202 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-50: New North Sat. Plant Pressures, SE Quadrants Purdue University 8-62 Burns & McDonnell

203 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Figure 8-51: New North Sat. Plant Velocities Purdue University 8-63 Burns & McDonnell

204 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Conclusions The results from the model indicate that there are a number of buildings, mainly concentrated in the northeast part of campus, which are not receiving adequate pressure from the supply side of the chilled water system to provide sufficient flow through the building. As more buildings are added to the campus over the next five years, the system will supply less pressure to the northeast side of campus. The issue is exacerbated by the fact that a number of buildings in the northeast corner appear to have undersized piping, resulting in high water velocities through the pipelines. While all of the improvement scenarios that were presented provide some relief for the velocities leaving the satellite plant and the pressure challenges in the NE corner of campus, the addition of the new 18 east/west distribution path would provide significant relief and provide connection for future loads in this area of campus. As outlined in subsequent sections capacity needs necessitate the addition of a new plant. The NE corner of campus is the ideal location for this plant from a distribution perspective. If an alternate location is considered for this plant it is recommended that the plant be located as close as possible to the NE area of campus. Table 8-12 summarizes the costs of each improvement option. Table 8-12: Chilled Water System Improvement Option Summary Scenario Improvement Cost 5-Year Scenario - NW Plant Secondary Pump Upgrade $960,000 New 18" East-West Pipeline $1,900,000 New North Satellite Plant/TES $20 to $28 million $ Several branch connections to buildings were found to be undersized based on the loads provided for that building. It is recommended that the loads and pipe sizes for these buildings be verified. A summary of these branch lines can be found in Table 8-13 below. All values are based on 5-Year scenario model results. Table 8-13: Chilled Water Branch Line Summary Building Branch Pipe Size Building Load Velocity (in) (gal/min) (ft/sec) Forney Hall 4 1, Physics C Physics S Brown Chemistry Labs 6 1, Wetherill Chemistry Labs 6 1, Purdue University 8-64 Burns & McDonnell

205 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Stewart Center 8 2, Lynn Hall of Vet. Medicine 6 2, DEMAND SIDE MANAGEMENT EFFECT The foreseen distribution issues with steam and chilled water prompted the investigation into problem areas of the campus, the worst being the northeast section. Buildings were selected for investigation with the goal of identifying possible building specific steam and chilled water demand reduction opportunities. In particular these buildings were selected due to their location and high demand relative to other campus buildings. The results were to be extrapolated to several other campus buildings in problem areas in an effort to relieve distribution bottlenecks Building Investigation The two buildings were surveyed from a demand-only point-of-view to focus on demand reduction opportunities. At the time of the survey, Hansen Life Sciences Building and Lynn Hall had already been surveyed. The estimated demand savings in these two buildings provided a data point for estimating high-level savings potential in Forney Hall and Heine Pharmacy Building. Both Forney and Heine were surveyed with participating IAQ technicians familiar with building operations. Both buildings are classified as Research/Lab buildings and have similar overall space use as Hansen and Lynn. Efforts were focused on outside air quantities, conditioning, and delivery. Demand reduction opportunities were estimated based on the site investigation and building observations. The results of the review of these two facilities are not included in the extrapolated campus wide demand side management program Selection of Buildings Forney Hall and Heine Pharmacy Building were selected for investigation, due to their location on the campus and their estimated demand on the steam and chilled water distribution systems. Purdue University 8-65 Burns & McDonnell

206 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Forney Hall of Chemical Engineering Forney Hall totals 177,676 square feet, comprised of the original 1938 building and the newer core addition finished in There is a distinct difference between the two areas with regards to lab exhaust hardware. Exhaust air for the older perimeter section of the building is removed via multiple small fans in the attic, most equipped with VFDs. However, these VFDs are used to maintain a constant total exhaust from each space, a combination of fume hood and general exhaust air. The supply air to these spaces is also constant volume, supplied through smaller AHUs. The majority of the space heating and cooling loads are served by in-room fan-coil units. Although the labs in this area of the building would be classified as constant air volume, it is questionable whether the spaces are receiving enough ventilation air from the small fresh-air AHUs. Demand savings for these areas are estimated to be minimal. The new core area of the building is exhausted via one large fume hood exhaust manifold and one large general exhaust manifold. Phoenix air valves in the general exhaust from each space react inversely to the Phoenix valves on the fume hoods, resulting in constant air volume exhaust from each space. Supply air is delivered at a constant rate through Titus supply air valves to each space. The three large AHUs serving the Titus air valves have VFDs on the fans that serve only as soft-starts. Demand savings in this area is estimated to be major, and at a low relative cost. Phoenix valves already exist in the exhaust air streams, and VFDs exist on the AHUs supplying air to the spaces. With the addition of Phoenix air valves on the supply air, and modulation of airflow to each space, significant demand savings could be realized due to lower airflow and less outside air conditioning. It is estimated for the building as a whole that 10% demand reduction is possible with modifications to existing air delivery and exhaust methods. Although there is significant opportunity in the new area of the building, the possibility that the older areas are under-ventilated reduces possible demand reduction if the spaces were to be brought up to ventilation standards Heine Pharmacy Building Heine Pharmacy Building was built in 1967 and has not undergone a major space renovation. However, many of the space-dedicated exhaust fans were removed and replaced with an exhaust manifold and Strobic fans. Purdue University 8-66 Burns & McDonnell

207 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Exhaust air from the lab areas is removed via one of two methods. Approximately half of the spaces are exhausted through the fume hood sash and hood bypass grill with individual constant-speed exhaust fans in the fifth floor mechanical space. These fans blow into a roof well where air is exhausted via several large Strobic fans. Other spaces are exhausted through the fume hood sash and bypass by connection directly to the roof well manifold. Phoenix air valves are installed in the exhaust duct from each space to regulate a constant air volume. Air is supplied to all lab spaces via several large 100% fresh-air AHUs with Titus air valves and dual-duct mixing boxes, both of which maintain constant air volume to each space. Significant opportunity for demand savings exists in this building due to the constant air volume through the lab spaces. In addition, most of the office areas of the building are supplied with 100% fresh air via a large AHU in the basement. The air from these areas can be re-circulated back to the AHU instead of directly exhausted. Testing and balancing analysis would be required to determine how much of this air is necessary as transfer air to the corridor and lab spaces. This would require evaluation before the office areas could be converted to recirculation. It is estimated for the building as a whole that 20% demand reduction is possible with modifications to existing air delivery and exhaust systems Steam In order to simulate the potential effect that focused building demand reductions may have on distribution improvement planning a 20% peak load reduction in the following buildings was modeled. Recreational Sports Center Forney Hall of Chemical Engineering Heine Pharmacy Building Neil Armstrong Hall of Engineering These reductions resulted in an increase of approximately 10 psi in the delivered pressure on the high pressure steam system. Purdue University 8-67 Burns & McDonnell

208 Comprehensive Energy Master Plan FINAL DRAFT 8.0 Distribution Modeling Chilled Water In order to simulate the potential effect that focused building demand reductions may have on distribution improvement planning a 20% peak load reduction in the following buildings was modeled. Forney Hall of Chemical Engineering Heine Pharmacy Building Neil Armstrong Hall of Engineering These reductions resulted in an increase of approximately 2 psi in the delivered pressure in the NE corner of campus Conclusions These localized demand reduction efforts do not significantly affect previous discussion regarding the chilled water distribution system. However, the impact to the steam delivered pressure was significant enough to warrant further consideration. These buildings should be considered high priorities for ECM implementation due to the potential to delay steam system distribution improvements and improve overall system performance. * * * * * Purdue University 8-68 Burns & McDonnell

209 Comprehensive Energy Master Plan FINAL DRAFT 9.0 Dispatch Management Tool Review 9.0 DISPATCH MANAGEMENT TOOL REVIEW Purdue has developed an Excel-based dispatch decision tool. The tool determines if it is economically advantageous to purchase electric power from Duke at the current RTP price, or to produce electric power at the Wade Utility Plant by condensing steam in TG1.The figure below is a screenshot of the tool. Figure 9-1: Purdue Dispatch Management Tool Screenshot The tool utilizes the following data (the data labeled Current is automatically updated in the spreadsheet via the PI system): Hourly RTP price Hourly Base Purchase Amount Hourly Minimum Self-Generation (MW produced when the Wade Utility Plant is dispatched to meet campus thermal loads, with no additional steam for condensing in TG1) Estimated Labor and Maintenance cost Current System Electrical Load Current Electric Purchase from Duke Purdue University 9-1 Burns & McDonnell

210 Comprehensive Energy Master Plan FINAL DRAFT 9.0 Dispatch Management Tool Review Current Discretionary Power (equal to Current Load minus Base Purchase minus Minimum Self-Generation) Current Fuel Cost (called Live Fuel Cost in spreadsheet) The spreadsheet uses the data above to determine the cost of producing electricity at the Wade Utility Plant by condensing steam in TG1. This is called the Wade Strike Price. If the current Duke RTP price is less than the Wade Strike Price, then the tool will make a recommendation to buy power. Conversely, if the Wade Strike Price is less than the current Duke RTP price, the tool will recommend self-generating. The current tool provides valuable operating information and a good overall approach to making dispatch decisions. However, there may be opportunities to further refine the tool. These potential enhancements are discussed below. It is important to include margin and Contract Riders in the Dispatch Management Tool to accurately reflect Purdue s opportunities to save on electricity costs by self-generating with TG1. It appears that the Dispatch Management tool does not include RTP demand charges as part of the decision making process. The tool may recommend purchasing an amount of RTP that exceeds the month-to-date maximum RTP demand, and in some cases the incremental demand charge incurred may be more than the amount saved on electricity costs. There may be economic value in developing the tool such that it will evaluate the projected electrical demand to determine an optimal peak RTP demand for every month. There are numerous factors that have an effect on Wade s cost to produce electricity by condensing steam in TG1. One important factor is the cost of fuel. Purdue s diversified mix of fuel sources means that for any given hour, the incremental cost of steam can vary significantly depending on which boilers are operating and which boilers have spare capacity to produce steam. Therefore, when making dispatch decisions, it is important to take spare boiler capacity into consideration along with fuel price. Another important factor is TG1 performance. The heat rate of TG1 varies significantly with changes in throttle flow and with changes in the ratio of LP section flow to extraction flow. The figure below shows how TG1 heat rate changes as a function of LP section flow for various extraction flows. Purdue University 9-2 Burns & McDonnell

211 Comprehensive Energy Master Plan FINAL DRAFT 9.0 Dispatch Management Tool Review Figure 9-2: TG1 Heat Rate as a Function of LP Section Flow 15,000 14,000 0 TG1 Heat Rate (BTU/kWh) 13,000 12,000 11,000 10,000 9,000 8,000 7,000 6, TG1 LP Section Flow The lines on the graph above represent turbine extraction flow. As shown, when TG1 extraction flow is below 100 kpph, then increasing LP section flow will improve the overall heat rate of the turbine. Conversely, when TG1 extraction flow is above 100 kpph, increasing LP section flow will decrease the overall heat rate. These changes in heat rate can have a significant impact on the Wade Strike Price and are evaluated as part of the dispatch decision-making process. TG1 output is affected by condenser pressure. As shown in the figure below, TG1 output drops roughly one megawatt for each inch of mercury of condenser pressure increase. The ambient wet bulb temperature and cooling tower load should be taken into account when evaluating the Wade Strike Price. Purdue University 9-3 Burns & McDonnell

212 Comprehensive Energy Master Plan FINAL DRAFT 9.0 Dispatch Management Tool Review Figure 9-3: TG1 Output The dispatching of auxiliary equipment at the Wade Utility Plant can also have an impact on the total cost of operation for any given hour. As described in the Utilization of Steam Driven Assets section above, the decision of whether to drive auxiliary assets at the Wade Utility Plant with steam or electricity can be complex, and has implications related to the operation of TG1 and TG2. The decision of whether or not to condense an incremental amount of steam in TG1 should be weighed against the opportunity to use that steam in a steam driven asset. Overall the current dispatch tool is good and very beneficial for Purdue. However with some enhancements, the performance could be even better and allow Purdue to operate with even more economic efficiency. * * * * * Purdue University 9-4 Burns & McDonnell

213 Comprehensive Energy Master Plan FINAL DRAFT 10.0 Base Purchase Calculator Review 10.0 BASE PURCHASE CALCULATOR REVIEW Near the end of every calendar year, Purdue sends Duke Energy a schedule, by hour, of the amount of Base Supplemental Capacity and Energy it expects to require during the upcoming year. The energy charge for this power is $ per kwh. In March 2011, Contract Riders were equal to $ per kwh, making the total cost for Base Purchase energy $.0343 per kwh. In addition to the energy charges, Purdue is charged $12.26 per kw per month for capacity; the capacity charge is based on the maximum amount of Base Purchase declared out of all hours of the month. Duke Energy charges Purdue for the energy actually used, rather than the energy declared. The capacity charge, however, is fixed based on the maximum amount that is declared. The capacity and energy supplied by Duke Energy that is in excess of the declared Base Purchase amount is considered RTP Energy/Capacity, and is charged based on hourly MISO prices. Duke Energy adds a 10% margin on the MISO price, and charges for Contract Riders, which totaled $ /kWh in March The charge for RTP capacity is $1.593 per kw. With a goal of minimizing electricity costs, Purdue has developed an Excel-based tool to determine the amount of Base Purchase to declare for every hour of the upcoming year. The figure below is a screenshot of the tool. Figure 10-1: Base Purchase Spreadsheet For the purposes of setting Base Purchase amounts, Purdue divides up the hours of the day into three timeframes as follows: Purdue University 10-1 Burns & McDonnell

214 Comprehensive Energy Master Plan FINAL DRAFT 10.0 Base Purchase Calculator Review Table 10-1: Daily Timeframes Off Peak 11PM 5AM Shoulder 5AM 9AM and 8PM 11PM Peak 9AM 8PM The spreadsheet will determine an amount of Base Purchase for each of the timeframes. This is determined on a month-by-month basis, so each month of the year can have a unique Base Purchase amount for each of the three timeframes. To determine the amount of Base Purchase, the spreadsheet takes the minimum system electrical load during a specific timeframe for a certain month, and subtracts the amount of electricity that will be produced by TG1 and TG2 when dispatched to meet campus steam demands. The figure below shows the average hourly price of RTP (margin and riders included, demand charges excluded) for fiscal year 2010 (July 2009 to June 2010) in blue, with the cost in $/MWh shown on the left side. It also shows the average hourly total system electric load for the same time period in red, with the load in MW shown on the right. (Note that each curve has a different scale in order to highlight the shapes of the curves. When plotted on the same scale, the electric load appears flatter, as it only varies by about 30%, whereas the price of RTP varies by about 70%). Peak hours are shown in pink, Shoulder hours in green, and Off Peak hours in blue. Figure 10-2: Average Hourly RTP Price and Electric Load - FY2010 As shown in the figure, RTP prices remain quite high during the first two hours of the afternoon shoulder (8PM and 9PM). Extending the peak Base Purchase period through 9PM or 10PM will allow Purdue to Purdue University 10-2 Burns & McDonnell

215 Comprehensive Energy Master Plan FINAL DRAFT 10.0 Base Purchase Calculator Review take advantage of the lower cost of Base Purchase energy ($34.33/MWh), without increasing the Base Purchase demand charge. Using the historic RTP prices and electric loads from FY2010, and assuming a minimum self-generation of 12 MW from TG1 and TG2, high level analysis indicates that extending the peak base purchase amount through 10PM would have saved roughly $59,000 in FY2010. Eliminating the morning shoulder period and making it equal to peak would have saved roughly $34,000. (Note that calendar year 2011Base Purchase amounts were used, and assumed to be similar to FY 2010 amounts). Extend Peak base Purchase Time Frame Potential Annual Savings 6am to 8am $34,000 8pm to 10pm $59,000 * * * * * Purdue University 10-3 Burns & McDonnell

216 Comprehensive Energy Master Plan FINAL DRAFT 11.0 Review of Design Standards 11.0 REVIEW OF DESIGN STANDARDS Purdue has developed a Consultant s Handbook that describes Purdue s requirements for specific building components to the design engineers. A cursory review of the Consultant s Handbook was performed that focused on the effect these components would have on the campus utility systems GENERAL REQUIREMENTS The general requirements (02 Design Philosophy) indicate that Purdue expects the technical systems to be MORE reliable than in private industry. We assume the intent of this section is to indicate that Purdue expects the technical system to be MORE reliable than a typical commercial building; however that is not was it says. This section could be clarified CHILLED WATER SYSTEM COMPONENTS Some of the most important components of the chilled water to be executed properly are the cooling coil sizing criteria, the cooling coil control valve selection and finally how that control valve is controlled. All three of these are addressed well in the Consultant s Handbook. 1. Pressure independent control valves are required for modulating service. 2. Information on how to properly select the cooling coil is located in Section The Handbook does not discuss specific control strategies, which is consistent to many other building design standards. The idea being that Purdue does not want to limit the engineer s design by calling out specific design strategy. This is normally dealt with during the design review process. However as indicated earlier in this report, Purdue performs the control system design HVAC SYSTEMS The standard referenced is out of date. The current standard is AHRI Performance Rating of Central Station Air-Handling Units HVAC STEAM AND CONDENSATE PIPING Some minor modifications are recommended for this section. The first would be to also specify inner rings on spiral wound gaskets. Second is to utilize Schedule 80 pipe in small sizes where threaded fittings are used and third to utilize ductile iron fittings instead of cast iron. * * * * * Purdue University 11-1 Burns & McDonnell

217 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis 12.0 ECONOMIC ANALYSIS The goal of this economic analysis is to evaluate several options to add chilled water, electric and steam production capacity to Purdue s existing assets to meet planned load growth and replace capacity that is planned to be retired. Several key decision points occur during the next 25 years based on the boiler, chiller, and steam turbine retirement schedules presented below. The key decision points are summarized below: 1. Boiler 1 and Chiller 6 at Wade are scheduled for retirement during the next few years. Replacing this steam production capacity with a traditional gas fired water tube boiler was compared to the installation of combined heat and power capacity. Replacing the retired chilled water production capacity with traditional electric centrifugal chillers was compared with the installation of thermal energy storage. Whether to install CHP and/or TES over the next few years was the primary focus of this analysis. 2. Several buildings were audited as a part of this CEMP to identify potential opportunities for reductions is energy consumption. As outlined in previous sections several opportunities were found. This analysis also includes the value of these modifications over the life of the analysis and the impact these modifications will have to the decisions required in Decision Point 1 above. 3. Boiler 2 is scheduled for retirement in This will be another key decision point for the university. Depending on the decisions made over the next few years the capacity may be replaced with either a traditional gas fired water tube boiler or CHP capacity. Due to the impact of retiring the remaining low sulfur coal capacity will have on overall fuel costs, CHP will likely be an economically viable solution for capacity replacement. Depending on the impact and schedule of demand side reductions, a remote steam plant may need to be considered at this point to address distribution concerns. 4. Steam Turbine 2 and Boiler 3 are scheduled to be retired in Depending on the decisions made at the key decision points listed above, careful consideration will need to be given to the technology and location of the capacity installed to meet load growth and replace retired capacity. The investment decisions outlined in 1 and 2 above will significantly impact the future decision points outlined in 3 and 4. Therefore, it is paramount that this analysis be revisited prior to making funding or planning decisions with regard to capacity installations in 2021 and Purdue University 12-1 Burns & McDonnell

218 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis 12.1 CHILLED WATER ASSETS Several key factors were considered in the development of the proposed chilled water infrastructure including: 1. Load growth profile. 2. Retirement and replacement of existing chilled water equipment. 3. Equipment and energy utilization for new equipment. 4. Location of future chilled water assets. Chilled water peak demand in 2011 was 30,400 tons. Load is expected to grow on campus at approximately 1.5% annually to slightly over 45,000 tons in 25 years. These load projections do not take into account demand reductions generated by ECM s implemented on the building side nor possible load increases resulting from elimination of the curtailment discussed in the previous section. The potential impact of ECM implementation is considered in the options analyzed and presented in this section. This plan recommends a conservative approach to develop and maintain adequate chilled water production capacity. The chilled water roadmap was developed utilizing an N+2 redundancy approach. Ultimately the timeline may have to be adjusted as the results of the building side renovation impacts on the central systems are realized, but the sequence installing additional capacity will not change. The retirement and replacement of existing equipment is a factor in the performance of the chilled water system. For the purposes of planning, 30 years has been used as the useful service life for the existing chillers, except for Wade Chiller 6 for which retirement in 2013 is recommended. Chiller Number Table 12-1: Chilled Water Asset Retirement Schedule Capacity (Tons) Driver Location Install. Date Mfr. Retire Date Steam Wade 1971 Carrier Steam Wade 1988 York Steam Wade 1994 Carrier Electric Wade 1999 Trane Electric Wade 2000 Trane Steam Wade 2001 York Electric NW Chiller Plant 2002 Trane Electric NW Chiller Plant 2002 Trane Electric NW Chiller Plant 2005 Trane Electric NW Chiller Plant 2007 Trane Electric NW Chiller Plant 2007 Trane 2037 Purdue University 12-2 Burns & McDonnell

219 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis As chillers are replaced, the question becomes: What is the optimum type of chiller to be used? Three cases were examined. 1. Base Case: Maintain the current mix of steam and electric chillers with additional capacity installed with electric drives. 2. Option One: Maintain the current mix of steam and electric chillers. Additional chillers needed for load growth to be installed as follows a. First new chiller with a steam drive b. Remaining new chillers being electric. 3. Option Two: Utilize electric chillers for all future chillers and all replacement chillers. Each of the cases assumes that TES is in place. If Purdue decides to not install TES, two or three additional chillers will be required to make up for that capacity. Each of these options was evaluated using the dispatch tool created for the CHP analysis. Comparing the Base Case to Option One, the overall utility costs over 25 years is almost equal, with a $1,300 savings for the Base Case. It is estimated that a $750,000 increased capital cost is associated with the base case which yields a $933,000 NPV savings using the electric chillers. Option Two yielded a $34,000 in utility savings over 25 years at an even lower first cost than Option One. Based on this information, the recommendation is to use electric chillers for capacity additions and replacements as steam driven chillers are retired tons was used as the standard increment for each new chiller. This size allows purchase of chillers with a single compressor, reduces the firm capacity size over time, and matches recent chiller installations on campus. The final question is the location of the new chilled water assets. Distribution modeling is addressed in detail in Section 8.0. There are distribution issues on the northeast side of campus. The overall pressure drop across campus from both existing plants creates significant pressure challenges in the NE corner of campus. The net result is a significant need for tertiary pumping and potentially inadequate supply pressure to existing buildings as the load continues to grow. The optimal location for the new Satellite Chiller plant is in the stadium area. However, another location can be accommodated by adding east-west distribution capacity in the northern part of campus. Early development of this plant will relieve the current flow issues in this part of campus. The roadmaps for the facility recommend the construction of a Purdue University 12-3 Burns & McDonnell

220 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis new satellite plant after the installation of Chiller 6 in the NW Satellite Plant (SP2) in It is assumed that this plant will host the TES as well as two chillers for the first phase STEAM PRODUCTION Several key factors were considered in the development of the proposed steam production infrastructure plan including: 1. Load growth profile. 2. Retirement and replacement of existing steam production equipment. 3. Equipment and energy utilization for new equipment. 4. Location of future steam production assets due to distribution limitations. Analysis of the steam flow rates for 2010 indicated a plant production of approximately 640 MMBtu/hr. Load is expected to grow on campus at approximately 1.5% annually to slightly over 800 MMBtu/hr in 25 years. These load projections do not take into account energy savings generated by ECMs implemented on the building side or possible load increases resulting from the elimination of chilled water curtailment discussed in the previous section. However, the peak load projections do take into account reductions in steam load due to the retirement of steam driven chillers and the effect of coal boiler retirement on steam turbine condensing demand. The potential impact of ECM implementation is considered in the options analyzed and presented in this section. The retirement and replacement of existing equipment is a key factor in the performance of the steam system. The retirement schedule used as a basis for steam production planning was based on information provided by Purdue University staff, equipment age, and industry standards. The assets being retired are listed below. Table 12-2: Steam Production Asset Retirement Schedule Asset Retirement Year Boiler Boiler Boiler As each of these assets is retired, replacement capacity must be installed. Over the next five years the steam distribution system has enough capacity to handle planned growth with some modifications. However, over the next 20 years the system will be taxed by additional load growth resulting in insufficient pressure on the north end of campus. As the campus master plan and load growth becomes Purdue University 12-4 Burns & McDonnell

221 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis more clearly defined, the University will have to seriously consider a remote steam plant or make significant investment to upgrade the north/south distribution capacity across campus. The firm capacity line in the graphs below represents the steam production capacity available with the largest installed boiler out of service. The plan keeps this line above the peak plant production forecast. The peak production line represents the total steam production required to run the plant auxiliary equipment and generate additional electrical load in addition to the steam exported to campus ELECTRIC PRODUCTION The electric production plan is driven primarily by the need for additional steam production capacity and the economic viability of meeting this need with CHP capacity. In order to focus on decision points in the near future it was assumed that Steam Turbine 2 remains in operation for the next 25 years. This turbine has a finite life and replacement will need to be carefully considered in light of capacity decisions made over the next five years. Additional chilled water capacity to meet future growth is anticipated to be installed on the north end of campus. Careful consideration should be given in regarding the location of electric generating assets. The potential to serve significant additional electrical loads on the north end of campus from Wade needs to be carefully analyzed as the overall campus load profile grows INSTALLATION PROGRAM OPTIONS ANALYZED Six unique asset installation programs were analyzed for meeting the future campus electric, chilled water, and steam loads. The following table outlines the projects included in each of the options analyzed. Table 12-3: Matrix of Options Analyzed DSM Program TES Tank CHP Base Case Option 1 Option 2 Option 3 Option 4 Option 5 Purdue University 12-5 Burns & McDonnell

222 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Assumptions The following assumptions were included in the analysis presented in this section. Analysis begins in 2013 Capital, operations, and maintenance costs were analyzed over 25 years All debt is retired by 2038, the last year analyzed. 4.5% discount rate 4.5% interest rate on new debt. 3% annual non-fuel O&M inflation rate 3% annual capital cost escalation Variability in distribution upgrade costs between options is not included. Internal Rate of Return (IRR) is calculated using the present value (PV) of future additional debt payments and the PV of energy savings over 25 years. Commodity escalation rates are outlined in the table below. Engineering estimates for capital costs are ±30%. Purdue University 12-6 Burns & McDonnell

223 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Table 12-4: Commodity Escalation Rates LS Coal Unit Cost ($/Tons) $95.72 $91.22 $96.01 $82.80 $84.93 $87.90 $90.98 $94.16 $97.46 $ $ $ $ $ $ LS Coal Heat Content (Btu/lb) 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 LS Coal Unit Cost ($/MMBtu) $4.35 $4.15 $4.36 $3.76 $3.86 $4.00 $4.14 $4.28 $4.43 $4.59 $4.75 $4.91 $5.08 $5.26 $5.45 Escalation Rate (%) -4.7% 5.3% -13.8% 2.6% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% HS Coal Unit Cost ($/Tons) $50.93 $58.20 $62.60 $64.79 $67.03 $69.38 $71.80 $74.32 $76.92 $79.61 $82.40 $85.28 $88.27 $91.36 $94.55 HS Coal Heat Content (Btu/lb) 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 HS Coal Unit Cost ($/MMBtu) $2.32 $2.65 $2.85 $2.95 $3.05 $3.15 $3.26 $3.38 $3.50 $3.62 $3.75 $3.88 $4.01 $4.15 $4.30 Escalation Rate (%) 14.3% 7.6% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% Limestone Unit Cost ($/Tons) $31.58 $33.38 $35.22 $37.24 $38.25 $38.50 $40.58 $41.79 $43.05 $44.34 $45.67 $47.04 $48.45 $49.90 $51.40 Escalation Rate (%) 5.7% 5.5% 5.7% 2.7% 0.7% 5.4% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Average Henry Hub Gas Price ($/MMBtu) $3.98 $4.46 $4.11 $4.61 $5.02 $5.30 $5.54 $5.76 $6.20 $6.39 $6.58 $6.78 $6.98 $7.19 $7.40 Escalation Rate (%) 12.0% -7.8% 12.1% 8.9% 5.6% 4.5% 4.0% 7.7% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Gas Transportation ($/MMBtu) $1.00 $1.00 $1.00 $1.00 $1.00 $1.00 $1.00 $1.00 $1.00 $1.03 $1.06 $1.09 $1.13 $1.16 $1.19 Escalation Rate (%) 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Delivered Gas Price ($/MMBtu) $4.98 $5.46 $5.11 $5.61 $6.02 $6.30 $6.54 $6.76 $7.20 $7.42 $7.64 $7.87 $8.10 $8.35 $8.60 Base Electric Purchase - Energy ($/kwh) $ $ $ $ $ $ $ $ $ $ $ $ $ $ Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Base Electric Purchase - Demand ($/kw) $12.26 $12.63 $13.01 $13.40 $13.80 $14.21 $14.64 $15.08 $15.53 $16.00 $16.48 $16.97 $17.48 $18.00 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Base Electric Purchase - Riders ($/kwh) $ $ $ $ $ $ $ $ $ $ $ $ $ $ RTP Demand Charge ($/kw) $1.59 $1.64 $1.69 $1.74 $1.79 $1.85 $1.90 $1.96 $2.02 $2.08 $2.14 $2.21 $2.27 $2.34 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% RTP Energy Riders ($/kwh) $ $ $ $ $ $ $ $ $ $ $ $ $ $ Duke Margin on MISO RTP Purdue University 12-7 Burns & McDonnell

224 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Table 12-5: Commodity Escalation Rates LS Coal Unit Cost ($/Tons) $ $ $ $ $ $ $ $ $ $ $ $ $ $ LS Coal Heat Content (Btu/lb) 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 LS Coal Unit Cost ($/MMBtu) $5.64 $5.83 $6.04 $6.25 $6.47 $6.69 $6.93 $7.17 $7.42 $7.68 $7.95 $8.23 $8.52 $8.81 Escalation Rate (%) 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% HS Coal Unit Cost ($/Tons) $97.86 $ $ $ $ $ $ $ $ $ $ $ $ $ HS Coal Heat Content (Btu/lb) 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 11,000 HS Coal Unit Cost ($/MMBtu) $4.45 $4.60 $4.77 $4.93 $5.10 $5.28 $5.47 $5.66 $5.86 $6.06 $6.27 $6.49 $6.72 $6.96 Escalation Rate (%) 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% Limestone Unit Cost ($/Tons) $52.94 $54.53 $56.17 $57.85 $59.59 $61.37 $63.21 $65.11 $67.06 $69.08 $71.15 $73.28 $75.48 $77.75 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Average Henry Hub Gas Price ($/MMBtu) $7.63 $7.86 $8.09 $8.33 $8.58 $8.84 $9.11 $9.38 $9.66 $9.95 $10.25 $10.56 $10.87 $11.20 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Gas Transportation ($/MMBtu) $1.23 $1.27 $1.30 $1.34 $1.38 $1.43 $1.47 $1.51 $1.56 $1.60 $1.65 $1.70 $1.75 $1.81 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Delivered Gas Price ($/MMBtu) $8.86 $9.12 $9.40 $9.68 $9.97 $10.27 $10.57 $10.89 $11.22 $11.56 $11.90 $12.26 $12.63 $13.01 Base Electric Purchase - Energy ($/kwh) $ $ $ $ $ $ $ $ $ $ $ $ $ $ Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Base Electric Purchase - Demand ($/kw) $18.54 $19.10 $19.67 $20.26 $20.87 $21.50 $22.14 $22.81 $23.49 $24.20 $24.92 $25.67 $26.44 $27.23 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% Base Electric Purchase - Riders ($/kwh) $ $ $ $ $ $ $ $ $ $ $ $ $ $ RTP Demand Charge ($/kw) $2.41 $2.48 $2.56 $2.63 $2.71 $2.79 $2.88 $2.96 $3.05 $3.14 $3.24 $3.34 $3.44 $3.54 Escalation Rate (%) 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% 3.0% RTP Energy Riders ($/kwh) $ $ $ $ $ $ $ $ $ $ $ $ $ $ Duke Margin on MISO RTP Purdue University 12-8 Burns & McDonnell

225 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Base Case The base case represents a traditional approach to meeting chilled water and steam capacity needed over the life of the analysis. The following asset installation assumptions were used as a basis for establishing this reference case. Traditional, natural gas fired, water tube boilers are installed to meet load growth and compensate for planned capacity retirements. Electrical centrifugal chillers are installed as needed to meet load growth and compensate for planned capacity retirements. The existing satellite plant is built out first, subsequently several chillers are installed at the proposed new satellite plant, followed by replacing retiring capacity at Wade with new electrical centrifugal chillers. No load decrease is included due to ECM or DSM project implementation. This case represents the largest annual operating cost and highest overall cost of ownership Demand (Building) Modifications This option does not include any modifications to the energy use of the buildings Steam The following asset retirement and installation schedule was assumed for the Base Case. Table 12-6: Base Case Steam Asset Roadmap Asset Fuel Capacity (MMBTU/hr) Install. Year Retire. Year $2012 Capital Cost Boiler 1 Stoker Coal Boiler 2 Stoker Coal Boiler 3 Natural Gas Boiler 5 CFB Coal Boiler 7 Natural Gas Boiler 8 Natural Gas $6,800,000 Boiler 9 Natural Gas $6,800,000 Boiler 10 Natural Gas $6,800,000 Purdue University 12-9 Burns & McDonnell

226 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis 1400 Figure 12-1: Base Case Steam Asset Roadmap MMBTU/hr BLR 3 BLR 7 BLR 8 BLR 9 BLR 10 BLR 2 BLR 5 Peak N+1 Plant Peak Purdue University Burns & McDonnell

227 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Chilled Water The following chilled water asset retirement and installation schedule was assumed for the Base Case. Table 12-7: Base Case Chilled Water Roadmap Asset Capacity (Tons) Type Location Install. Year Retire. Year $2012 Capital Cost CH-1NW 2000 Electric NWCP CH-2NW 2000 Electric NWCP CH-3NW 2000 Electric NWCP CH-4NW 2700 Electric NWCP CH-5NW 2700 Electric NWCP CH-6W 6250 Steam Wade CH-7W 3000 Steam Wade CH-8W 4500 Steam Wade CH-9W 2000 Electric Wade CH-10W 2000 Electric Wade CH-11W 5000 Steam Wade CH-6NW 2700 Electric NWCP CH Electric SP CH Electric SP CH Electric SP $26,600,000 CH Electric SP CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 Purdue University Burns & McDonnell

228 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-2: Base Case Chilled Water Roadmap Peak N NW 3NW 3NW 4NW 4NW 11W 11W 1NW 11W 11W 4NW 4NW 4NW 5NW 5NW 2NW 1NW 11W 11W 11W 8W 8W 8W 8W 8W 8W 10W 9W 9W 3NW 5NW 5NW 5NW 6NW 6NW 2NW 7W 7W 7W 7W 1NW 10W 10W 9W 9W 9W 3NW 4NW 6NW 6NW 6NW NW 7W 1NW 1NW 11W 11W 11W 11W 11W 11W 8W 8W 8W 8W 10W 10W 10W 3NW 4NW 5NW NW 2NW 1NW 1NW 1NW 8W 9W 9W 9W 9W 9W 9W 3NW 3NW 4NW 5NW 6NW 2NW 2NW 2NW W 11W 11W 11W 11W 10W 10W 10W 10W 10W 10W 3NW 3NW 3NW 4NW 4NW 5NW 6NW NW 1NW 1NW 1NW 1NW 1NW 11W 9W 9W 9W 9W 4NW 4NW 4NW 5NW 5NW 6NW NW 2NW 2NW 2NW 2NW 2NW 7W 10W 10W 10W 10W 9W 3NW 3NW 3NW 3NW 3NW 3NW 5NW 5NW 5NW 6NW 6NW W 1NW 1NW 1NW 1NW 10W 4NW 4NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 2NW 2NW 2NW 2NW 1NW NW 3NW 3NW 3NW 5NW 5NW 5NW 5NW 5NW 5NW 2NW W 3NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 6NW 6NW 6NW W 4NW 5NW 5NW 5NW 5NW W 5NW 6NW 6NW 6NW 6NW 1NW 6NW NW 3NW NW NW NW Tons The peak line above represents peak campus demand. The yellow line represents available capacity with the two largest chilled water assets out of service, N Option 1 Implementation of Thermal Energy Storage (TES) This option assumes the same steam production installation philosophy and schedule outlined in the Base Case. However, 8,000 tons of TES capacity is initially installed in lieu of traditional electrical centrifugal chillers. This capacity will defer larger capital investments needed in the chilled water system and provide energy cost savings through utilization the daily variability in electricity prices. TES can be installed at a lower cost per ton than building a new chilled water plant Steam Option 1 does not include any changes to the steam asset roadmap as compared with the Base Case and the asset retirement and installation schedule is repeated in the following table and figure. Purdue University Burns & McDonnell

229 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Asset Table 12-8: Option 1 Steam Asset Roadmap Fuel Capacity (MMBTU/hr) Install. Year Retire. Year $2012 Capital Cost Boiler 1 Stoker Coal Boiler 2 Stoker Coal Boiler 3 Natural Gas Boiler 5 CFB Coal Boiler 7 Natural Gas Boiler 8 Natural Gas $6,800,000 Boiler 9 Natural Gas $6,800,000 Boiler 10 Natural Gas $6,800, Figure 12-3: Option 1 Steam Asset Roadmap MMBTU/hr BLR 3 BLR 7 BLR 8 BLR 9 BLR 10 BLR 2 BLR 5 Peak N+1 Plant Peak Purdue University Burns & McDonnell

230 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Chilled Water Asset Table 12-9: Option 1 Chilled Water Roadmap Capacity (Tons) Type Location Install. Year Retire. Year $2012 Capital Cost CH-1NW 2000 Electric NWCP CH-2NW 2000 Electric NWCP CH-3NW 2000 Electric NWCP CH-4NW 2700 Electric NWCP CH-5NW 2700 Electric NWCP CH-6W 6250 Steam Wade CH-7W 3000 Steam Wade CH-8W 4500 Steam Wade CH-9W 2000 Electric Wade CH-10W 2000 Electric Wade CH-11W 5000 Steam Wade CH-6NW 2700 Electric NWCP TES 8000 TES $6,800,000 CH Electric SP $14,000,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 Purdue University Burns & McDonnell

231 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-4: Option 1 Chilled Water Roadmap Peak N+2+TES NW 3NW 3NW 4NW 4NW 11W 11W 1NW 11W 11W 4NW 4NW 4NW 5NW 5NW 2NW 1NW 11W 11W 11W 8W 8W 8W 8W 8W 8W 10W 9W 9W 3NW 5NW 5NW 5NW 6NW 6NW 2NW 7W 7W 7W 7W 1NW 10W 10W 9W 9W 9W 3NW 4NW 6NW 6NW 6NW NW 7W 1NW 1NW 11W 11W 11W 11W 11W 11W 8W 8W 8W 8W 10W 10W 10W 3NW 4NW 5NW NW 2NW 1NW 1NW 1NW 8W 9W 9W 9W 9W 9W 9W 3NW 3NW 4NW 5NW 6NW 2NW 2NW 2NW W 11W 11W 11W 11W 10W 10W 10W 10W 10W 10W 3NW 3NW 3NW 4NW 4NW 5NW 6NW NW 1NW 1NW 1NW 1NW 1NW 11W 9W 9W 9W 9W 4NW 4NW 4NW 5NW 5NW 6NW NW 2NW 2NW 2NW 2NW 2NW 7W 10W 10W 10W 10W 9W 3NW 3NW 3NW 3NW 3NW 3NW 5NW 5NW 5NW 6NW 6NW W 1NW 1NW 1NW 1NW 10W 4NW 4NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 2NW 2NW 2NW 2NW 1NW NW 3NW 3NW 3NW 5NW 5NW 5NW 5NW 5NW 5NW 2NW W 3NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 6NW 6NW 6NW W 4NW 5NW 5NW 5NW 5NW W 5NW 6NW 6NW 6NW 6NW 1NW 6NW NW 3NW NW 5NW TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES 0 6NW Tons Option 2 Implementation of TES and Combined Heat & Power CHP In addition to the chilled water implementation schedule outlined in Option 1, Option 2 includes 6.5MW of combined heat and power capacity utilizing a natural gas fired combustion turbine and heat recovery steam generator. This option assumes CHP capacity is installed after the retirement of Boiler 1 in Subsequent steam generating capacity required is assumed to be in the form of traditional natural gas fired, water tube boilers. Implementation of TES decreases but does not eliminate the overall economic advantage of CHP capacity by reducing the summer peak electric demand. The value of CHP relative to the base case without TES is approximately $6,200,000 over the life of the analysis. Purdue University Burns & McDonnell

232 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Steam Asset Table 12-10: Option 2 Steam Asset Roadmap Fuel Capacity (MMBTU/hr) Install. Year Retire. Year $2012 Capital Cost Boiler 1 Stoker Coal Boiler 2 Stoker Coal Boiler 3 Natural Gas Boiler 5 CFB Coal Boiler 7 Natural Gas T65 & HRSG(8) Natural Gas $15,200,000 Boiler 9 Natural Gas $6,800,000 Boiler 10 Natural Gas $6,800, Figure 12-5: Option 2 Steam Asset Roadmap MMBTU/hr BLR 3 BLR 7 BLR 9 BLR 10 T65/HRSG BLR 2 BLR 5 Peak N+1 Plant Peak Chilled Water Option 2 does not include any changes to the chilled water roadmap as compared with Option 1 and the asset retirement and installation schedule is repeated in the following table and figure. Purdue University Burns & McDonnell

233 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Asset Table 12-11: Option 2 Chilled Water Roadmap Capacity (Tons) Type Location Install. Year Retire. Year $2012 Capital Cost CH-1NW 2000 Electric NWCP CH-2NW 2000 Electric NWCP CH-3NW 2000 Electric NWCP CH-4NW 2700 Electric NWCP CH-5NW 2700 Electric NWCP CH-6W 6250 Steam Wade CH-7W 3000 Steam Wade CH-8W 4500 Steam Wade CH-9W 2000 Electric Wade CH-10W 2000 Electric Wade CH-11W 5000 Steam Wade CH-6NW 2700 Electric NWCP TES 8000 TES $6,800,000 CH Electric SP $14,000,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 Purdue University Burns & McDonnell

234 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-6: Option 2 Chilled Water Roadmap Peak N+2+TES NW 3NW 3NW 4NW 4NW 11W 11W 1NW 11W 11W 4NW 4NW 4NW 5NW 5NW 2NW 1NW 11W 11W 11W 8W 8W 8W 8W 8W 8W 10W 9W 9W 3NW 5NW 5NW 5NW 6NW 6NW 2NW 7W 7W 7W 7W 1NW 10W 10W 9W 9W 9W 3NW 4NW 6NW 6NW 6NW NW 7W 1NW 1NW 11W 11W 11W 11W 11W 11W 8W 8W 8W 8W 10W 10W 10W 3NW 4NW 5NW NW 2NW 1NW 1NW 1NW 8W 9W 9W 9W 9W 9W 9W 3NW 3NW 4NW 5NW 6NW 2NW 2NW 2NW W 11W 11W 11W 11W 10W 10W 10W 10W 10W 10W 3NW 3NW 3NW 4NW 4NW 5NW 6NW NW 1NW 1NW 1NW 1NW 1NW 11W 9W 9W 9W 9W 4NW 4NW 4NW 5NW 5NW 6NW NW 2NW 2NW 2NW 2NW 2NW 7W 10W 10W 10W 10W 9W 3NW 3NW 3NW 3NW 3NW 3NW 5NW 5NW 5NW 6NW 6NW W 1NW 1NW 1NW 1NW 10W 4NW 4NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 2NW 2NW 2NW 2NW 1NW NW 3NW 3NW 3NW 5NW 5NW 5NW 5NW 5NW 5NW 2NW W 3NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 6NW 6NW 6NW W 4NW 5NW 5NW 5NW 5NW W 5NW 6NW 6NW 6NW 6NW 1NW 6NW NW 3NW NW 5NW TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES 0 6NW Tons Option 3 Implementation of Demand Side Management (DSM) Projects This option utilizes that same steam and chilled water production asset installation and replacement philosophy as outlined in the Base Case. However, the year in which capacity additions are needed is significantly influenced by implementing ECM s and DSM projects across campus over a six year period from 2013 through 2018 at an expense of approximately $5 million a year Demand (Building) Modifications This option includes the implementation of ECM/DSM projects as outlined in Table 3-15: Energy Savings Extrapolated to Campus. Purdue University Burns & McDonnell

235 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Steam As seen in the table and chart below, the implementation of ECM/DSM projects could allow for a delay in the installation of Boiler 10 by about nine years. This also applies to Option 4. This delay is not possible with Option 5 because the steam production capacity of the proposed HRSG would not be as high as the proposed Boiler 8 capacity. Asset Table 12-12: Option 3 Steam Asset Roadmap Fuel Capacity (MMBTU/hr) Install. Year Retire. Year $2012 Capital Cost Boiler 1 Stoker Coal Boiler 2 Stoker Coal Boiler 3 Natural Gas Boiler 5 CFB Coal Boiler 7 Natural Gas Boiler 8 Natural Gas $6,800,000 Boiler 9 Natural Gas $6,800,000 Boiler 10 Natural Gas $6,800, Figure 12-7: Option 3 Steam Asset Roadmap MMBTU/hr BLR 3 BLR 7 BLR 8 BLR 9 BLR 10 BLR 2 BLR 5 Peak N+1 Plant Peak Purdue University Burns & McDonnell

236 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Chilled Water The following chilled water asset retirement and installation schedule was assumed for Option 3. The installation of Chiller 17 is delayed four years due to the implementation of DSM projects. Asset Table 12-13: Option 3 Chilled Water Roadmap Capacity (Tons) Type Location Install. Year Retire. Year $2012 Capital Cost CH-1NW 2000 Electric NWCP CH-2NW 2000 Electric NWCP CH-3NW 2000 Electric NWCP CH-4NW 2700 Electric NWCP CH-5NW 2700 Electric NWCP CH-6W 6250 Steam Wade CH-7W 3000 Steam Wade CH-8W 4500 Steam Wade CH-9W 2000 Electric Wade CH-10W 2000 Electric Wade CH-11W 5000 Steam Wade CH-6NW 2700 Electric NWCP CH Electric SP CH Electric SP CH Electric SP $26,573,489 CH Electric SP CH Electric Wade $1,814,517 CH Electric Wade $1,814,517 CH Electric SP $2,862,248 CH Electric SP $2,862,248 CH Electric SP $2,862,248 CH Electric Wade $1,814,517 CH Electric SP $2,862,248 CH Electric SP $2,862,248 CH Electric Wade $1,814,517 CH Electric Wade $1,814,517 CH Electric NWCP $1,744,105 CH Electric NWCP $1,744,105 CH Electric NWCP $1,744,105 CH Electric NWCP $1,744,105 Purdue University Burns & McDonnell

237 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-8: Option 3 Chilled Water Roadmap Peak N NW 3NW 3NW 4NW 4NW 11W 11W 1NW 11W 11W 8W 8W 4NW 4NW 4NW 5NW 5NW 2NW 1NW 11W 11W 11W 10W 8W 8W 8W 8W 9W 9W 3NW 5NW 5NW 5NW 6NW 6NW 2NW 7W 7W 7W 7W 7W 1NW 11W 11W 10W 10W 9W 9W 9W 3NW 4NW 6NW 6NW 6NW NW 1NW 1NW 11W 11W 11W 11W 8W 8W 8W 8W 8W 10W 10W 10W 9W 9W 3NW 4NW 5NW NW 2NW 1NW 1NW 1NW 6W 10W 10W 9W 9W 9W 9W 3NW 3NW 4NW 5NW 6NW NW 2NW 2NW 1NW 1NW 11W 11W 11W 11W 11W 10W 10W 10W 10W 3NW 3NW 3NW 4NW 4NW 5NW 6NW NW 2NW 7W 1NW 1NW 1NW 1NW 9W 9W 9W 9W 9W 3NW 3NW 4NW 4NW 4NW 5NW 5NW 6NW NW 2NW 2NW 2NW 8W 10W 10W 10W 10W 10W 3NW 3NW 3NW 3NW 4NW 4NW 5NW 5NW 5NW 6NW 6NW NW 1NW 1NW 1NW 1NW 4NW 4NW 4NW 4NW 5NW 5NW 6NW 6NW 6NW NW 2NW 2NW 2NW 2NW 11W 3NW 3NW 3NW 3NW 3NW 5NW 5NW 5NW 5NW 6NW 6NW W 4NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 6NW W 5NW 5NW 5NW 5NW 5NW 1NW 6NW 6NW 6NW 6NW 6NW 2NW 3NW NW NW NW Tons Option 4 Implementation of DSM Projects and TES This option utilizes that same steam asset installation and replacement philosophy as outlined in the Base Case. However, the year in which steam and chilled water capacity additions are needed is significantly influenced by implementing ECM s and DSM projects across campus over a six year period from 2013 through 2018 at an expense of approximately $5 million a year. In addition the TES installation philosophy outlined in Option 1 is applied to this option Demand (Building) Modifications This option includes the implementation of ECM/DSM projects presented in Table 3-15: Energy Savings Extrapolated to Campus. Purdue University Burns & McDonnell

238 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Steam Option 4 does not include any changes to the steam asset roadmap as compared with Option 3 and the asset retirement and installation schedule is repeated in the following table and figure. Asset Table 12-14: Option 4 Steam Asset Roadmap Fuel Capacity (MMBTU/hr) Install. Year Retire. Year $2012 Capital Cost Boiler 1 Stoker Coal Boiler 2 Stoker Coal Boiler 3 Natural Gas Boiler 5 CFB Coal Boiler 7 Natural Gas Boiler 8 Natural Gas $6,800,000 Boiler 9 Natural Gas $6,800,000 Boiler 10 Natural Gas $6,800, Figure 12-9: Option 4 Steam Asset Roadmap MMBTU/hr BLR 3 BLR 7 BLR 8 BLR 9 BLR 10 BLR 2 BLR 5 Peak N+1 Plant Peak Purdue University Burns & McDonnell

239 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Chilled Water The following chilled water asset retirement and installation schedule was assumed for Option 4. Asset Table 12-15: Option 4 Chilled Water Roadmap Capacity (Tons) Type Location Install. Year Retire. Year $2012 Capital Cost CH-1NW 2000 Electric NWCP CH-2NW 2000 Electric NWCP CH-3NW 2000 Electric NWCP CH-4NW 2700 Electric NWCP CH-5NW 2700 Electric NWCP CH-6W 6250 Steam Wade CH-7W 3000 Steam Wade CH-8W 4500 Steam Wade CH-9W 2000 Electric Wade CH-10W 2000 Electric Wade CH-11W 5000 Steam Wade CH-6NW 2700 Electric NWCP TES $6,900,000 CH Electric SP $14,000,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 Purdue University Burns & McDonnell

240 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-10: Option 4 Chilled Water Roadmap Peak N+2+TES NW 3NW 3NW 4NW 4NW 11W 11W 1NW 11W 11W 8W 8W 4NW 4NW 4NW 5NW 5NW 2NW 1NW 11W 11W 11W 8W 8W 8W 8W 10W 9W 9W 3NW 5NW 5NW 5NW 6NW 6NW 2NW 7W 7W 7W 7W 7W 1NW 11W 11W 10W 10W 9W 9W 9W 3NW 4NW 6NW 6NW 6NW NW 1NW 1NW 11W 11W 11W 11W 8W 8W 8W 8W 8W 10W 10W 10W 9W 9W 3NW 4NW 5NW NW 2NW 1NW 1NW 1NW 6W 10W 10W 9W 9W 9W 9W 3NW 3NW 4NW 5NW 6NW NW 2NW 2NW 1NW 1NW 11W 11W 11W 11W 11W 10W 10W 10W 10W 3NW 3NW 3NW 4NW 4NW 5NW 6NW NW 2NW 7W 1NW 1NW 1NW 1NW 9W 9W 9W 9W 9W 3NW 3NW 4NW 4NW 4NW 5NW 5NW 6NW NW 2NW 2NW 2NW 8W 10W 10W 10W 10W 10W 3NW 3NW 3NW 3NW 4NW 4NW 5NW 5NW 5NW 6NW 6NW NW 1NW 1NW 1NW 1NW 4NW 4NW 4NW 4NW 5NW 5NW 6NW 6NW 6NW NW 2NW 2NW 2NW 2NW 11W 3NW 3NW 3NW 3NW 3NW 5NW 5NW 5NW 5NW 6NW 6NW W 4NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 6NW W 5NW 5NW 5NW 5NW 5NW 1NW 6NW 6NW 6NW 6NW 6NW 2NW 3NW NW 5NW TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES 0 6NW Tons Option 5 Implementation of DSM Projects, TES, and CHP This option utilizes that same steam asset installation and replacement philosophy as outlined in Option 2 by installing CHP capacity in In addition the TES installation philosophy outlined in Option 1 is applied to this option. However, the year in which steam and chilled water capacity additions are needed is significantly influenced by implementing ECM s and DSM projects across campus over a six year period from 2013 through 2018 at an expense of approximately $5 million a year Demand (Building) Modifications This option includes the implementation of ECM/DSM projects presented in Table 3-15: Energy Savings Extrapolated to Campus. Purdue University Burns & McDonnell

241 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Steam Asset Table 12-16: Option 5 Steam Asset Roadmap Fuel Capacity (MMBTU/hr) Install. Year Retire. Year $2012 Capital Cost Boiler 1 Stoker Coal Boiler 2 Stoker Coal Boiler 3 Natural Gas Boiler 5 CFB Coal Boiler 7 Natural Gas T65 & HRSG Natural Gas $15,200,000 Boiler 9 Natural Gas $6,800,000 Boiler 10 Natural Gas $6,800, Figure 12-11: Option 5 Steam Asset Roadmap 1200 MMBTU/hr BLR 3 BLR 7 BLR 9 BLR 10 T65/HRSG BLR 2 BLR 5 Peak N+1 Plant Peak Chilled Water Option 5 does not include any changes to the chilled water roadmap as compared with Option 4 and the asset retirement and installation schedule is repeated in the following table and figure. Purdue University Burns & McDonnell

242 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Asset Table 12-17: Option 5 Chilled Water Roadmap Capacity (Tons) Type Location Install. Year Retire. Year $2012 Capital Cost CH-1NW 2000 Electric NWCP CH-2NW 2000 Electric NWCP CH-3NW 2000 Electric NWCP CH-4NW 2700 Electric NWCP CH-5NW 2700 Electric NWCP CH-6W 6250 Steam Wade CH-7W 3000 Steam Wade CH-8W 4500 Steam Wade CH-9W 2000 Electric Wade CH-10W 2000 Electric Wade CH-11W 5000 Steam Wade CH-6NW 2700 Electric NWCP TES $6,900,000 CH Electric SP $14,000,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric SP $2,900,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric Wade $1,800,000 CH Electric SP $2,900,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 CH Electric NWCP $1,800,000 Purdue University Burns & McDonnell

243 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-12: Option 5 Chilled Water Roadmap Peak N+2+TES NW 3NW 3NW 4NW 4NW 11W 11W 1NW 11W 11W 8W 8W 4NW 4NW 4NW 5NW 5NW 2NW 1NW 11W 11W 11W 8W 8W 8W 8W 10W 9W 9W 3NW 5NW 5NW 5NW 6NW 6NW 2NW 7W 7W 7W 7W 7W 1NW 11W 11W 10W 10W 9W 9W 9W 3NW 4NW 6NW 6NW 6NW NW 1NW 1NW 11W 11W 11W 11W 8W 8W 8W 8W 8W 10W 10W 10W 9W 9W 3NW 4NW 5NW NW 2NW 1NW 1NW 1NW 6W 10W 10W 9W 9W 9W 9W 3NW 3NW 4NW 5NW 6NW NW 2NW 2NW 1NW 1NW 11W 11W 11W 11W 11W 10W 10W 10W 10W 3NW 3NW 3NW 4NW 4NW 5NW 6NW NW 2NW 7W 1NW 1NW 1NW 1NW 9W 9W 9W 9W 9W 3NW 3NW 4NW 4NW 4NW 5NW 5NW 6NW NW 2NW 2NW 2NW 8W 10W 10W 10W 10W 10W 3NW 3NW 3NW 3NW 4NW 4NW 5NW 5NW 5NW 6NW 6NW NW 1NW 1NW 1NW 1NW 4NW 4NW 4NW 4NW 5NW 5NW 6NW 6NW 6NW NW 2NW 2NW 2NW 2NW 11W 3NW 3NW 3NW 3NW 3NW 5NW 5NW 5NW 5NW 6NW 6NW W 4NW 4NW 4NW 4NW 4NW 6NW 6NW 6NW 6NW W 5NW 5NW 5NW 5NW 5NW 1NW 6NW 6NW 6NW 6NW 6NW 2NW 3NW NW 5NW TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES TES 0 6NW Tons 12.5 ECONOMIC ANALYSIS A life cycle cost analysis (LCCA) was performed for each of the six options described above (Base Case and Options 1 through 5). The fuel and electricity costs were computed using an hourly dispatch model previously developed for the analysis performed in the Level I and II CHP studies. The financial model includes these fuel and electricity costs, along with O&M costs and bond payments to finance the capital projects for each option. The economic assumptions used in the dispatch and financial model are outlined above. The net present value of all fuel, electricity, O&M, and debt service expenditures was evaluated for each option in 2012 dollars. The analysis shows that all options have a lower life cycle cost when compared to the base case. Purdue University Burns & McDonnell

244 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis 12.6 RESULTS Table 12-18: Economic Analysis Summary NPV ($2012) NPV Savings IRR Base $755,042,379 Option 1 $743,306,226 $11,736,153 Infinite Option 2 $739,071,485 $15,970, % Option 3 $737,639,759 $17,402, % Option 4 $726,922,873 $28,119, % Option 5 $724,985,097 $30,057, % Figure 12-13: Total Life Cycle Cost ($2012) Millions $765 $755 $755.0 $745 $743.3 $739.1 $737.6 $735 $725 $726.9 $725.0 $715 $705 Base Option 1 Option 2 Option 3 Option 4 Option 5 Purdue University Burns & McDonnell

245 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-14: Total Life Cycle Cost Savings ($2012) $35 Millions $30 $28.1 $30.1 $25 $20 $16.0 $17.4 $15 $11.7 $10 $5 $ Option 1 Option 2 Option 3 Option 4 Option 5 The first year that the major capital improvements are installed is The summary of costs for the first year (2014) is shown in Table and Figure Table 12-19: 2014 Cost Summary Base Opt1 Opt2 Opt3 Opt4 Opt5 Base Case Option 1 Option 2 Option 3 Option 4 Option 5 Base Case TES TES, CHP DSM DSM, TES DSM, TES, CHP Operating Expenses GT Fuel $0 $0 $2,390,367 $0 $0 $2,284,445 HRSG Duct Burners $0 $0 $202,715 $0 $0 $113,949 CFB Coal & Limestone $9,221,863 $9,221,486 $9,055,050 $9,108,653 $9,125,140 $8,917,936 Stoker Coal $5,236,327 $5,033,298 $4,323,179 $4,864,956 $4,720,906 $3,970,249 Natural Gas Boilers $835,299 $747,707 $167,312 $558,841 $498,284 $89,788 RTP Energy $5,021,177 $5,137,379 $3,533,719 $4,910,644 $4,941,428 $3,498,062 RTP Demand $517,903 $561,847 $550,173 $510,421 $530,166 $505,209 Base Purchase Demand $2,732,954 $2,732,954 $2,732,954 $2,732,954 $2,732,954 $2,732,954 Base Purchase Energy $2,257,481 $2,257,481 $2,257,481 $2,257,481 $2,257,481 $2,257,481 Base Purchase Riders $2,433,410 $2,433,410 $2,433,410 $2,433,410 $2,433,410 $2,433,410 Operation and Maintenance $35,010 $14,004 $14,004 $28,008 $7,002 $7,002 GT LTSA $0 $0 $451,396 $0 $0 $451,396 Total Operating Expenses $28,291,423 $28,139,565 $28,111,759 $27,405,367 $27,246,770 $27,261,880 Non Operating Expenses New Debt Service $3,027,919 $2,657,748 $3,342,045 $3,735,926 $3,280,305 $3,964,602 Total Non Operating Expenses Total 2014 Expenditures $31,319,342 $30,797,313 $31,453,804 $31,141,294 $30,527,075 $31,226,482 Total 2014 Savings $522,029 ($134,462) $178,048 $792,267 $92,860 Purdue University Burns & McDonnell

246 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-15: 2014 Cost Summary (Millions) $35 $30 $25 $20 $15 $10 New Debt Service GT LTSA O&M RTP Demand RTP Energy HRSG Duct Burners GT Fuel Natural Gas Boilers Stoker Coal $5 CFB Coal & Limestone $0 Base Case Option 1 Option 2 Option 3 Option 4 Option 5 Base Purchase Demand Base Purchase Riders Base Purchase Energy Purdue University Burns & McDonnell

247 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Table 12-20: Life Cycle Cost Summary ($2012) Base Case Option 1 Option 2 Option 3 Option 4 Option 5 TES CHP, TES DSM DSM, TES DSM, TES, CHP Operating Expenses GT Fuel $0 $0 $60,309,963 $0 $0 $57,833,068 HRSG Duct Burners $0 $0 $34,032,051 $0 $0 $29,868,506 CFB Coal [1] $191,756,234 $191,756,882 $189,657,009 $189,564,601 $189,660,777 $186,673,050 Stoker Coal [2] $37,396,782 $36,149,447 $32,022,108 $34,011,571 $32,879,783 $28,601,368 Natural Gas - Boilers $148,005,160 $145,847,754 $84,551,625 $121,270,706 $118,765,392 $63,575,471 RTP Energy [3] $154,881,230 $152,840,701 $106,284,513 $144,598,408 $143,048,108 $99,556,617 RTP Demand $12,374,055 $12,781,168 $11,773,699 $11,825,992 $12,145,331 $11,258,253 Base Purchase Demand $53,039,303 $53,039,303 $53,039,303 $53,039,303 $53,039,303 $53,039,303 Base Purchase Energy $43,811,641 $43,811,641 $43,811,641 $43,811,641 $43,811,641 $43,811,641 Base Purchase Riders $35,270,727 $35,270,727 $35,270,727 $35,270,727 $35,270,727 $35,270,727 Operation and Maintenance $1,325,503 $917,837 $917,837 $1,197,955 $790,289 $790,289 GT LTSA $0 $0 $8,359,067 $0 $0 $8,359,067 Total Operating Expenses $677,860,635 $672,415,458 $660,029,542 $634,590,903 $629,411,350 $618,637,360 Non-Operating Expenses New Debt Service $77,181,744 $70,890,768 $79,041,944 $103,048,856 $97,511,523 $106,347,738 Total Non-Operating Expenses Total 2012 NPV Life Cycle Costs $755,042,379 $743,306,226 $739,071,485 $737,639,759 $726,922,873 $724,985,097 Total 2012 NPV Savings $11,736,153 $15,970,894 $17,402,620 $28,119,506 $30,057,282 IRR [4] Infinite 23.0% 8.3% 11.2% 9.6% [1] Includes limestone and ash disposal costs. [2] Includes ash disposal costs. [3] Includes margin and riders. [4] Internal Rate of Return, for calculation method see assumptions. Purdue University Burns & McDonnell

248 Comprehensive Energy Master Plan FINAL DRAFT 12.0 Economic Analysis Figure 12-16: Life Cycle Cost Summary ($2012) (Millions) $800 $700 $600 $500 $400 $300 $200 New Debt Service GT LTSA O&M RTP Demand RTP Energy HRSG Duct Burners GT Fuel Natural Gas Boilers Stoker Coal $100 $0 Base Option 1 Option 2 Option 3 Option 4 Option 5 CFB Coal & Limestone Base Purchase Demand Base Purchase Riders Base Purchase Energy DSM = Demand-Side Management TES = Thermal Energy Storage GT = Gas Turbine HRSG = Heat Recovery Steam Generator CFB = Circulating Fluidized Bed RTP = Real Time Power purchases LTSA = Long Term Service Agreement for Gas Turbine NPV = Net Present Value O&M = Operations and maintenance costs excluding fuel, electricity, and LTSA. * * * * * Purdue University Burns & McDonnell

249 Comprehensive Energy Master Plan FINAL DRAFT 13.0 Conclusions and Recommendations 13.0 CONCLUSIONS AND RECOMMENDATIONS Earlier chapters in the CEMP describe in detail many different aspects related to how Purdue uses energy, how energy is distributed to the campus and how it is produced in the energy plants. Chapter 12.0 analyzed the economics of several options. The intent of this chapter is to highlight the major conclusions that can be drawn from this analysis and recommend what options should be implemented DEMAND SIDE MANAGEMENT A sample of the building on campus was surveyed to identify energy savings opportunities and it confirmed Purdue s belief that energy savings potential exists in the campus facilities. Energy savings from the sample buildings was then extrapolated to campus to calculate a rough order of magnitude potential savings as indicated in Table Table 13-1: Campus Wide Energy Saving Potential Annual Energy Savings Electricity 10,500 MW-hr Heating 250,000 MMBtu Cooling 7,500,000 Ton-hrs Annual Demand (Peak) Savings Electricity 0.8 MW Heating 80 MMBtu/hr Cooling 2,800 Tons For Purdue to achieve these savings, several energy conservation measures (ECM s) would need to be implemented across the campus. The installation cost for these measures has a rough order of magnitude cost of $32 million with an associated energy savings of $2.6 million per year. Implementation of the ECM s would affect the majority of the major buildings on campus and would require several years to implement. For this analysis, it was assumed that the implementation of the ECM s would be performed over a six year period. To analyze the economics of implementing a demand side management (DSM) program, a comparison of the different options analyzed in Chapter 12.0 is required. Purdue University 13-1 Burns & McDonnell

250 Comprehensive Energy Master Plan FINAL DRAFT 13.0 Conclusions and Recommendations The results of the economic analysis indicate that implementation of demand side management measures has a significant net present value saving to Purdue. The table also indicates that as building energy is saved at the buildings, the benefit is reduced. However in every case the savings remains significant with a lowest benefit to Purdue of over $14.1 million. Therefore, we recommend that Purdue University implement a campus wide demand side management program to reduce the energy used in the buildings. In addition, this program will save Purdue money and like any energy reduction effort, it provides an environmental benefit of reducing the amount of resources consumed and emissions into the atmosphere. Observations developed as part of the survey in conjunction with interview of building operators, occupants and the University s facility operations team includes the following items: Based on the conditions observed, it appears that the maintenance of the buildings has not been supported with adequate resources to keep them in repair and operating efficiently. Zone maintenance personnel could benefit from additional training and access to the building automation system to correct building operational issues. Maintenance personnel are reliant on the Building Systems Group for system troubleshooting. New Lab/Research spaces on campus maintain a minimum occupied air exchange rate of six Air Changes per Hours (ACH). Opportunities exist in selected existing labs to reduce the air change rate during occupied and unoccupied times while offering significant reductions in energy. Our understanding is that Purdue is currently working to reduce air change rates in labs during unoccupied times. Space temperature set back is currently not utilized in a majority of campus locations. Rooms that have varying occupancy patterns based on academic calendar, occupancy and/or scheduled events and do not have a regular occupancy schedule have a high opportunity for energy savings. Most of the campus facilities that were investigated currently utilize high flow water devices (urinals, faucets, toilets, etc). There are numerous opportunities to save water by retrofitting these fixtures with low flow devices CONTROL SYSTEMS Purdue s building control systems are currently monitored by the Purdue University Building Systems Group who works with the Purdue University IAQ Team to respond to trouble calls. In addition, the Building Systems Group is also involved with the design of controls systems for the new and renovated buildings on campus. Purdue University 13-2 Burns & McDonnell

251 Comprehensive Energy Master Plan FINAL DRAFT 13.0 Conclusions and Recommendations Purdue utilizes control systems from two different control companies (Automatic Logic and Siemens) and has two different user interfaces. Both control systems utilize a complex user interface that requires a high degree of understanding of the control system. In addition, all of the control information is located with the Building Systems Group and very little if any information is located out at the buildings where the IAQ technicians that are maintaining the buildings can access and utilize that information. This results in the Building Systems Group staff becoming involved with every trouble call throughout the campus. A more user friendly interface to the control system would allow the IAQ technicians to access the information they need without involving the Building Systems Group and it would free up the Building Systems Group to focus on more campus wide initiatives. Section 4.0 has sample control systems graphics that have been utilized at other locations. Both control companies on the Purdue campus offer modern graphical user interfaces that provide a more user friendly experience. In addition, the access to the control system can be at the building level; however IAQ technicians would need additional training on how to take full advantage of the control systems capabilities. Cross-training of staff and introduction of new staff to the operations and programming efforts performed by the Building Systems Group is critical. The University s entire controls programming and operations knowledge base rests with just a few senior staff members (Console Group) who have responsibilities as shown on Figure Figure 13-1: Existing Controls System Responsibilities Purdue University 13-3 Burns & McDonnell

252 Comprehensive Energy Master Plan FINAL DRAFT 13.0 Conclusions and Recommendations Integration of team activities with structured communication and training has the potential to significantly improve the performance. Figure 13-2 provides diagram of the interrelated responsibilities. Figure 13-2: Proposed Control System Responsibilities An order of magnitude cost to implement was obtained from controls vendors for the control system improvements identified in the surveyed buildings. The pricing received had noticeable variability; however it did provide a range of $1 million to $2 million in a onetime cost. In addition to the review of the control system and how it is utilized by Purdue staff, an abnormal chilled water temperature control sequence was observed in a number of buildings. This sequence controls the chilled water control valve on cooling coils based on the return water temperature. The goal of this sequence is to increase the return water temperature to the plant to reduce pumping energy. Cooling coil control valves are normally controlled to maintain either a space temperature or a temperature of air leaving the cooling coil. Utilizing this control sequence compromises the system s ability maintain appropriate space temperature and humidity levels. We recommend implementation of a program to review the HVAC system control sequences and revise them as necessary to provide appropriate occupancy conditions in the buildings. Because some of the current control system sequences were implemented to compensate for other system deficiencies, this implementation must include the correction of any system deficiencies. This would include repair or Purdue University 13-4 Burns & McDonnell