CCC/IOU Statewide Partnership SCE Pilot RCx Program

Transcription

1 CCC/IOU Statewide Partnership SCE Pilot RCx Program Investigation Report College of the Desert Multi-Agency Library Monterey Ave Palm Desert, CA December 31, 2013 Prepared by (562) Copyright 2013 Southern California Edison. All rights reserved. Reproduction or distribution of the whole, or any part of the contents of this document without written permission of SCE is prohibited. Neither SCE nor any of its employees makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any data, information, method, product or process disclosed in this document, or represents that its use will not infringe upon any privately-owned rights, including but not limited to, patents, trademarks or copyrights.

2 CONTENTS 1. EXECUTIVE SUMMARY INTRODUCTION Project Contacts FACILITY DESCRIPTION Occupancy HISTORICAL ENERGY USE Electricity Consumption Natural Gas Consumption Total Cost of Energy Benchmarking Typical Load Profile from 15 Minute Interval Data RCX PLAN RCx Process Roles and Responsibilities Project Schedule Program Measurement & Verification Requirements DESCRIPTION OF SYSTEMS EVALUATED, SITE CONTROLS, AND TRENDING CAPABILITY Primary Energy Using Systems SUMMARY OF RECOMMENDED RCX MEASURES Description of RCx Measures OTHER MEASURES CONSIDERED APPENDICES December 31, 2013 i

3 Investigation Report: College of the Desert Multi-Agency Library 1. EXECUTIVE SUMMARY The CCC/IOU Partnership is made up of participation from the Chancellor s office for California Community Colleges, Southern California Edison (SCE), Southern California Gas (SoCal Gas), Pacific Gas & Electric Company (PG&E) and San Diego Gas & Electric (SDG&E). In conjunction with the CCC/IOU Partnership, Southern California Edison and Southern California Gas are piloting a Retrocommissioning (RCx) program which has been designed to assist customers in the identification and funding of energy efficiency measures that improve the operation of eligible facilities. All identified campuses for this pilot will be limited to the SCE and SCG service territories. This focus of this RCx project is on the Multi-Agency Library (MAL) at the College of the Desert. Based on utility billing data, the subject facility consumes approximately 920,000 kwh of electricity annually, with an annual peak demand of 223 kw. The site uses gas for space heating and water heating, and consumed 18,455 therms last year. The RCx project includes five energy-saving measures, which are summarized in Table 1.1 on the following page. Over the course of this investigation, kw Engineering has identified the energy-saving measures, calculated the estimated energy and cost savings as well as the implementation cost and potential utility incentive for each measure. The calculations were performed based on a collection of real time usage data, observing building operational settings, and by using spreadsheet calculations. The measures include numerous repairs and control upgrades to the central plant and air-side systems. If all the measures are implemented, College of the Desert can expect to reduce their annual energy consumption by an estimated 375,568 kwh and 5,875 therms, while reducing their peak demand by 21.9 kw. To determine these savings we calculated energy savings estimates and applied a 20% reduction factor to in order to ensure a conservative estimate. This reduction factor did not affect the calculated incentive, since the incentive is capped by the eligible project cost. We independently estimated the costs for these retrofits using cost databases such as RS Means, or based on direct quotes from College of the Desert s current contractors. The total estimated cost for all measures is $77,475. This cost covers the de-scaling of the condenser system as well as repairs and re-programming costs for BAS system components in both the air-side and central plant systems. Per program rules, incentives are capped at 80% of the eligible project cost. Based on the current savings, the incentive is capped. The cost-capped incentive for this project s electrical savings is $56,270. There are no gas incentives because the gas savings do not meet the SoCalGas incentive threshold. This incentive may change once SoCalGas participation in this project is clarified. The current incentive reduces the simple payback period for this project to 0.4 years. Since final incentive amounts are based on verified energy savings and costs, these numbers are preliminary figures only and may increase or decrease depending on the final verified figures. December 31,

4 Investigation Report: College of the Desert Multi-Agency Library The next step of the RCx project is to review the proposed measures, ultimately selecting the measures College of the Desert will implement, sign and submit the Project Agreement to SCE, implement the measures selected per kw Engineering s recommendations, and notify kw Engineering and your Account Representative when the implementation of all measures is complete. After implementation, kw Engineering will verify the installation and energy savings, write a Verification Report documenting the verified savings, review the changes made with the Campus' facility staff through a training session, and College of the Desert will receive an incentive for their verified energy savings. December 31,

5 Investigation Report: College of the Desert Multi-Agency Library Table 1.1: Summary Table of Investigated Energy Efficiency Measures 1 Measure Number RCx-1 Measure Name Shut off HVAC During Unoccupied Hours Peak (kw) Annual Energy, Cost and GHG Energy (kwh/yr) Energy (therm/yr) Annual Cost CO2 Emissions Avoided (tons/yr) Estimated (Pre-Retrofit) Estimated Measure Cost Potential 2013 Incentive Project Financials Net Measure Cost Simple Payback (yr) NPV MIRR ,818 5,397 $ 23, $ 8,280 $ 6,014 $ 2, $ 144,830 22% RCx-2 Air-Side Controls Retro-commissioning , $ 16, $ 47,745 $ 34,677 $ 13, $ 59,203 10% RCx-3 Repair/Restore Economizer Control 0.0 7,577 (382) $ $ 5,175 $ 3,759 $ 1, $ (623) 5% RCx-4 RCx-5 Optimize Condenser Water System and Cooling Tower Operation Optimize Chilled Water Pump VFD Control ,939 0 $ 6, $ 9,900 $ 7,190 $ 2, $ 29,671 13% 1.3 7,736 0 $ $ 6,375 $ 4,630 $ 1, $ (593) 5% SUB-TOTALS ,568 5,875 $ 47, $ 77,475 $ 56,270 $ 21, $ 232,488 13% Adjustment Factor 80% Assuming Electricity Cost : $ 0.12 /kwh Assuming Gas Cost : $ 0.75 /therm Assuming CO2 Reduction Equivalents : lbs CO2/kWh (for marginal energy use reductions) lbs CO2/therm RCx Incentives RCx Program Max Incentive Rates Cost Cap for total project 80% of costs Financials Rate Electric Peak Demand $0.00 per peak kw NPV Discount Rate for ROI 5% Electric Use $0.24 per kwh Finance Rate for MIRR 50% Gas $1.00 per therm Reinvestment Rate for MIRR 6% SCE Cost Split 91% $ 56,270 Capped at 80% of SCE Project Cost SCG Cost Split 9% $ - No cost savings beyond SoCalGas Value Added Services (no incentive) Notes on MIRR The Internal Rate of Return (IRR) allows comparison of the financial return of projects through their expected lives. Attractive projects have an IRR greater than the cost of money. Precisely, IRR is the discount rate which yields a Net Present Value of zero. The Modified IRR (MIRR) provides realistic values in all cases by applying an expected reinvestment rate for cash inflows. Prepared by David Gilliland (562) Measures with a simple payback period (SPP) without incentive of less than 3 years require implementation within 12 months per the terms and conditions listed in the SCE RCx Program Agreement. 1 SoCalGas may provide additional incentives up to $1 per therm saved ($5,875 based on current calculations), which will be confirmed at a later date. December 31,

6 2. INTRODUCTION The RCx Investigation Report provides a description of the retrocommissioning (RCx) investigation findings for College of the Desert in Palm Desert, CA. The document summarizes the preliminary planning for the site investigation, identification of RCx measures, and an approach to measure and verify the impacts associated with potential energy efficiency measures. This study is sponsored by SCE with support from the CCC/IOU Statewide Partnership. The RCx program provides assistance to SCE customers to identify and fund energy efficiency projects. The goal of the RCx program is to implement the following types of measures: Fix problems with existing controls Enhance the control and operation of existing equipment and systems Make limited repairs/upgrades to existing equipment so that it will operate more efficiently Taking advantage of the enhanced electrical incentive rates that the CCC/IOU Partnership offers its customers to save energy, this pilot program aims to use a portion of that incentive to buy down the customer's upfront engineering costs, which have traditionally been a barrier to participation with CCC campuses. Using clear cost effectiveness metrics to appropriately scale the RCx Provider's effort and budget, this pilot seeks a true win-win between all parties involved: Customer's RCx investigation and verification study costs are transferred to the utility in exchange for slightly less incentive on the back end. Customer still receives the yearly energy savings from RCx modifications. Utility is able to reach more customers and claim cost effective RCx energy savings from customers who would otherwise be unable to participate in 3P or Core Programs. Incentives are scaled so to ensure target cost effectiveness is achieved. December 31,

7 2.1. Project Contacts The project team for this building is shown in the table below: Table 2.1: Project Contacts Name Role Organization Contact Information Steve Renew Director of Facilities College of the Desert (760) Kevin Snyder Assistant Director of Facilities College of the Desert (760) Bruce Perry Senior HVAC Mechanic College of the Desert (760) Steven Clarke Senior Program Newcomb Anderson (415) Manager McCormick Amy Discher Account Manager Southern California Edison (714) Jay Caputo Project Manager Dynalectric (858) Ron Beeler CCC/IOU Facilities Planning (714) Partnership Manager & Program Services David Gilliland RCx Agent kw Engineering (562) December 31,

8 3. FACILITY DESCRIPTION The Multi-Agency Library (MAL) at the College of the Desert ( the college ) is a 41,205 square-foot building in Palm Desert, CA. The building is used by both the college and by the city of Palm Desert as a public library. The north side of the building is owned and occupied by the college, and the south side is public, though the college manages the facilities for the entire building. The library has a dedicated central utility plant with a water-cooled chiller, cooling towers, and a hot water boiler. Space conditioning in the building is provided by five air handling units (AHUs). Four of these units are variable air volume (VAV) systems that serve numerous zones throughout the building. The fifth AHU is a constantvolume unit that serves one room. The building was originally built in In 2008, the building underwent a major renovation. This renovation replaced the central plant equipment including the chillers, but did not install new AHUs. In 2012, the public (south) side of the building was retrofitted. According to the college this renovation revealed and resulted in numerous HVAC issues in the space due to improper wiring, clogged ductwork and coils from construction dust, disconnected thermostats, broken VAV dampers, and more. Additionally, the college found that many of the building automation system (BAS) controllers in their AHUs and VAV boxes are in disrepair. As a result, the HVAC system in the building is not functioning optimally at this time Occupancy The library has two separate occupancy schedules one for the north side of the building which is occupied by the college, and one for the south side of the building which is occupied by the city. The city-side of the library operates using the following year-round schedule: Table 3.1: MAL South Schedule Day Open Close Mon - Thu 10:00 am 8:00 pm Fri - Sat 10:00 am 5:00 pm Sun 1:00 pm 5:00 pm The north side of the library is closed during the month of August when there are no classes. When classes are in session, the library is open the following hours: December 31,

9 Table 3.2: MAL North Schedule Day Open Close Mon - Thu 8:00 am 8:00 pm Fri 8:00 am 5:00 pm Sat - Sun Closed Closed Though the library is not occupied 24 hours per day, the HVAC system is currently set on a 24/7 schedule. As a result, space temperatures are being maintained at their occupied set points throughout both the occupied and unoccupied times. Site facilities staff stated that the schedule is manually set to 24/7, particularly during the summertime, to ensure that the building remains cool. We were told that the schedule is revised to more closely match the occupancy during non-summer months, though we have no firsthand verification of this. Figure 3.1: 24/7 Operating Schedule December 31,

10 kwh/day Peak kw kw Engineering 4. HISTORICAL ENERGY USE This section provides a review of the electricity consumption (kwh) and electric demand (kw), at the College of the Desert s Multi-Agency Library Electricity Consumption The MAL has one electrical meter, #V349N This account is billed under SCE s TOU-GS3-B Service Agreement. The following table and figure show the electricity consumption history at this site. Table 4.1: Monthly Electricity Demand, Consumption, and Cost Month Peak Demand (kw) Electricity Consumption (kwh) Total Electricity Cost ($) Jun ,079 $ 6,991 Jul ,097 $ 10,347 Aug ,982 $ 11,237 Sep ,428 $ 12,119 Oct ,492 $ 7,859 Nov ,703 $ 8,049 Dec ,170 $ 6,508 Jan ,994 $ 6,543 Feb ,199 $ 7,642 Mar ,478 $ 8,882 Apr ,039 $ 9,779 May ,983 $ 10,171 Annual Totals ,165 $ 106,419 4, ,500 3, , ,000 1, , Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Electricity Consumption Rate [kwh/day] Peak Demand [kw] Figure 4.1: Monthly Electricity Consumption and Demand December 31,

11 The data shows a typical weather-based load profile. Electricity consumption is typically much higher in the summer due to increased cooling demand with most electric usage occurring during the hottest hours of mid-summer days. The data also shows that the average energy consumption has increased between 2012 and Months April through May in 2013 show significantly higher energy consumption than June through July in Site staff confirmed that the building was renovated in late 2012 and the renovation resulted in malfunctions of many mechanical systems. These malfunctions continue to persist, resulting in significantly higher energy consumption this year compared to the same month from the previous year Natural Gas Consumption The following table and figure show the natural gas consumption history for the past year from December 2012 to November 2013 for the entire library. There is one natural gas meter for the building. Month Natural Gas Consumption (therms) Total Gas Cost ($) Dec-12 1,637 $1,238 Jan-13 2,401 $1,632 Feb-13 2,165 $1,526 Mar-13 1,158 $818 Apr-13 1,714 $1,293 May-13 1,875 $1,444 Jun-13 1,308 $1,101 Jul $522 Aug $527 Sep-13 1,003 $778 Oct-13 1,863 $1,357 Nov-13 2,132 $1,610 Annual Totals 18,455 $ 13,846 Average Cost of Gas ($/therm) $ Table 3.2: Monthly Natural Gas Consumption and Estimated Cost The gas data, like the electrical, shows a typical weather-based profile. The gas consumption drops in the summer when space heating is not frequently required, and increases in the winter when it is cold outside. The gas consumption load profile can be seen in the graph below. December 31,

12 $/month Therms per Month kw Engineering 3, Historical Gas Consumption 2, , , , Dec-12 Jan-13 Feb-13 Mar-13 Apr-13 May-13 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov Total Cost of Energy Figure 4.2: Monthly Natural Gas Consumption Rates Based on the energy costs described above, the total annual cost of energy at the College of the Desert s Multi-Agency Library is just under $120,000. The following figure shows the monthly breakdown of electric and gas costs. $14,000 $12,000 $10,000 $8,000 $6,000 $4,000 $2,000 $- Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Total Electricity Cost ($) Total Gas Cost ($) Figure 4.3: Estimated Total Monthly Energy Costs As seen in the graph above, the expenditure for electrical energy is significantly higher than that for gas. As a result, our expectation from this project was to find significant electrical energy savings, while additionally capturing as much gas savings as possible. December 31,

13 kwh/ft² - Electricty Use kbtu/ft² - Natural Gas Use kw Engineering 4.4. Benchmarking Benchmarking compares the energy use of this building to those of similar size and purpose. To put facilities of different size on an equal footing, the energy use is compared on a per square foot basis. CAL-Arch Energy Use Intensity The Cal-Arch Building Energy Reference Tool compiles data from the California Commercial End-Use Survey (CEUS), which is a comprehensive study of commercial sector energy use. A stratified random sample of 2,790 commercial facilities was collected from the service areas across California and divided by utility service area, climate region, and building type. The charts below show a reference to similar type buildings within the same climate region. Lower use intensities correspond to higher performing buildings % College of the Desert Multi-Agency Library 75% % 25% College of the Desert Multi- Agency Library 50% 25% Figure 4.4: Electricity Use Intensity The electricity benchmark shows above average electricity use compared other education facilities in the south coast climate zone defined by Cal-Arch. This climate zone includes locations that do not utilize mechanical cooling and ventilation. Nevertheless, the above graph suggests that there is significant opportunity for electrical energy savings on site Typical Load Profile from 15 Minute Interval Data 15 minute interval data was obtained from the Account Representative and analyzed to extract further information about the facility s energy consumption patterns. Load profiles from a few key months are highlighted in the graph below. These graphs indicate that the library s energy consumption is primarily driven by the cooling load. The total building load increases during the middle of the day and during the warmer months due to the increased cooling load, and decreases at night when the building is unoccupied and outdoor air temperatures are cooler. December 31,

14 12:00 AM 2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00 PM 2:00 PM 4:00 PM 6:00 PM 8:00 PM 10:00 PM Avg Value kw Engineering Apr 2012 May 2012 Jun 2012 Apr 2013 May 2013 Jun Figure 4.4: MAL Energy Consumption Profile This graph also shows a clear increase in overall energy consumption between 2012 and The load during the occupied hours has increased significantly, though the load shape during that time is the same. Additionally, the 2013 data shows significantly higher energy consumption during the unoccupied hours compared to the 2012 data. This indicates that there are numerous energy-using systems that are now running at night that were not operating previously. These nighttime loads are likely an unnecessary waste of energy and should be eliminated. December 31,

15 5. RCX PLAN The objective of this RCx project is to: Pinpoint deficiencies in existing energy-consuming systems and related controls Identify potential optimization strategies for these systems. Assist the owner in Implementing corrective actions, operational and maintenance (O&M) improvements, and energy conservation measures (ECMs, or measures) that optimize existing equipment to produce sustainable reductions in energy consumption and demand. Verify the implementation of measures and report back to the Owner and SCE the achieved savings. To achieve these objectives, kw Engineering has conducted comprehensive on-site investigations and analysis to identify and document cost-effective energy saving opportunities RCx Process To accomplish the project objectives, a rigorous and comprehensive on-site investigation and analysis of facility operations has identified deficiencies and potential optimization strategies for the operation of the facility's energy consuming systems and related controls. Site work included survey, investigation and analysis of various mechanical systems for potential energy reduction measures. Investigation and analytical activities included the following: Gathering operational and functional performance data to assess equipment operation and identifying deficiencies and measures for improvement Gathering data to quantify facility operation and deficiencies using the appropriate methods for the facility Short term monitoring with portable data loggers and on-site measurements Review of existing construction drawings, air and water balance reports, and other pertinent reports December 31,

16 Table 5.1: Pilot CCC RCx Process Outline to Date Complete To Be Completed Application Investigation Implementation Verification Payment Complete RCx program application and obtain customer signature (SCE/SCG) Select RCx Provider (SCE/SCG & Customer) Perform screening audit and determine rough project potential (SCE/SCG & Provider) Agree upon project budget and set up contractual arrangement between customer and RCx Provider Conduct kickoff meeting introducing RCx program to customer (RCx Provider, Customer, SCE/SCG) Perform initial investigation of EEMs, develop PDRL and review with customer (RCx Provider & Customer) Perform detailed investigation of measures customers wishes to pursue (RCx Provider Review and approve RCx Investigation Report including M&V Plan (SCE/SCG) Issue Project Agreement (SCE/SCG) Sign Project Agreement (Customer, SCE/SCG) Implement EEMs in alignment with RCx Provider instructions (Customer, Contractor) Keep track of project costs on a measure by measure basis (Customer) Document implemented EEMs (RCx Provider) Perform postinstallation verification of EEMs (RCx Provider) Develop RCx Verification Report (RCx Provider) Review and approve RCx Verification Report including final incentive calculation (SCE/SCG) Provide training to customer to ensure measure persistence (RCx Provider) Issue RCx incentive check based on approved savings (SCE/SCG) and cost effectiveness guidelines Transmit check to customer (SCE/SCG) 5.2. Roles and Responsibilities Table 5.2: CCC Pilot RCx Roles and Responsibilities Role SCE/SCG Responsibilities SCE/SCG CCC Program Managers Approve list of pilot candidates and projects Approve RCx Provider budgets Approve RCx Pilot process decisions to ensure that Utility requirements are being met Ensure Program Forms and Documents meet utility requirements Participate in key RCx project meetings Evaluate Pilot program (customer satisfaction/cost effectiveness) at end of offering SCE/SCG Account Representatives Identify potential projects, obtain customer signatures on Program Application December 31,

17 and Project Agreement Route signed applications through proper program channels Distribute incentive payment Ensure customer satisfaction with RCx program throughout process Participate in key RCx project meetings Technical Support (Newcomb Anderson McCormick, NAM ) Develop and maintain program process, policies and procedures Answer questions from all parties throughout process (eligibility, process, technical) Pre-screen potential RCx customers, sites and projects Perform scoping audit and budget proposal evaluation Manage RCx Providers for each committed project Perform technical review of deliverables, calculate incentive Calculate incentive rates for customer based on project savings and engineering costs Provide project status updates Solicit feedback from all parties involved to improve future process Evaluate Pilot program (customer satisfaction/cost effectiveness) at end of offering RCx Provider Customer Contractor Conduct Kick Off with Customer following acceptance of project scope and budget Obtain baseline performance data & develop list of recommended EEM s Develop and submit Product Deficiency & Resolution Log (PDRL), RCx Investigation Report and M&V Plan for approval Verify measure implementation Develop and submit RCx Verification Report for approval Provide Customer training Work with SCE/SCG and RCx Provider to provide facility access and staff Gathers the building documentation, provides input into the investigation process Assists with the installation and removal of diagnostic equipment and implementation of the identified commissioning improvements (as needed) Install measures through contractors or internal labor Keeps track of project costs including internal labor, contracted labor and material costs on a measure by measure basis Responsible for installation of approved RCx measures and making system changes as specified by RCx Provider December 31,

18 5.3. Project Schedule Table 5.3: RCx Project Schedule ID Task Name Start Duration [Days] End 1 Project Start 07/16/13 2 Investigation Phase 07/16/ /18/ Schedule Kick-off Meeting 07/16/ /16/ Site Visits and Trend Data Collection 07/16/ /09/13 Draft Investigation Report 08/09/ /20/ Final Investigation Report 09/20/ /11/13 Present RCx Findings 10/11/ /18/13 3 Implementation Phase* 10/18/ /28/ Customer Installs Measures w/ kw's Support 10/18/ /18/ Review trend data to confirm proper implementation 12/18/ /28/13 4 Verification Phase 12/28/ /08/ Post Implementation Site Visit 12/28/ /11/ Trend Review and Calculation Adjustment 01/11/ /25/ Draft Verification Report 01/25/ /08/14 Final Verification Report 02/08/ /22/ Present RCx Verification Report 02/22/ /01/ Conduct On-Site Training 03/01/ /08/14 6 Payment from SCE 03/08/ /19/14 * NOTE: We have provided a best estimate for implementation time, but this is heavily dependent on the contractor and is beyond our control. December 31,

19 5.4. Program Measurement & Verification Requirements The RCx Program has established minimum levels of measurement and verification required to calculate and incentive energy savings. The detail and duration of data collection depends on the projected energy savings for each measure. Specific data points and the duration of data collection will be discussed further in Section 7.1: Description of RCx Measures. Table 5.4 below shows the measurement and verification guidelines that apply to all RCx projects. Measure Size Small (BOA Tool Applies) Table 5.4: RCx Measurement & Verification Guidelines Initial Calculation by Provider < 75,000 kwh/yr or < 5,000 th/yr Source of Initial Submitted BOA Tool Results Source of Final Claimed BOA Tool Results M&V Required Pre- and Post- Implementation Snapshot Small (BOA Tool Does Not Apply) < 75,000 kwh/yr or < 7,500 th/yr Initial Calculation by Provider Initial Calculation by Provider verified by snapshots Pre- and Post- Implementation Snapshot Medium 75,000 kwh/yr < < 200,000 kwh/yr or 7,500 th/yr < < 20,000 th/yr Large 200,000 kwh/yr < or 20,000 th/yr < Initial Calculation by Provider Initial Calculation by Provider Initial Calculation, Adjusted for Preand Post- Implementation Trends Calculations Based on Pre- & Post- Implementation Measurements Pre- and Post- Implementation Trend Logging Pre- and Post- Implementation Trend Logging December 31,

20 6. DESCRIPTION OF SYSTEMS EVALUATED, SITE CONTROLS, AND TRENDING CAPABILITY 6.1. Primary Energy Using Systems Cooling Cooling to the library is provided by a chilled water (CHW) system that contains one 200- ton water-cooled McQuay chiller with two Danfoss Turbocor frictionless centrifugal variable-speed compressors. Chilled water is distributed through the chiller and to the library using a primary-only pumping system. Lastly, heat is rejected through a 250-ton Marley 2-cell cooling tower with variable-speed fans. Additional information on the waterside system is provided below. Figure 6.1 Central plant chiller A summary of the cooling system equipment specifications is provided on the following tables. Table 6.1: Chillers Mark Model Capacity kw/ton Rated Flow CH-1 McQuay WMC250DSC15R 200 tons gpm Y The current control system is intended to operate the chillers using a chilled water supply temperature reset that varies the chilled water temperature from 43 F when the outdoor air temperature is over 80 F to a maximum of 46 F when the outdoor air temperature is less than 55 F. The trend data collected to date shows a constant 43 F supply temperature because the temperature has not dropped significantly below 80 F in the past month. VFD December 31,

21 Table 6.2: Primary Chilled Water Pumps Mark Model Flow Head Motor HP P-1 Armstrong Series x2.5x GPM 90 ft 10 hp Y P-2 Armstrong Series x2.5x GPM 90 ft 10 hp Y These pumps are equipped with variable frequency drives (VFDs), but operate at 100% speed any time the chiller plant is active. There is also a bypass valve in the primary loop that maintains a constant flow of 300 gpm through the chiller. Although the graphic below indicates that the flow meter is measuring 254 gpm to the chiller, the actual location of the flow meter is on the building side of the bypass valve. When cooling loads are low, and less flow is needed through the building, the bypass valve opens in order to decrease the flow to the building while maintaining the constant flow through the chiller. The exact control methodology for the bypass valve is unknown, as we could not collect any specific control sequences for the valve, and the valve position didn t change during our monitoring period. VFD Figure 6.2: Chilled Water Distribution December 31,

22 CWST ( F) Cooling Tower Fan Speed kw Engineering Mark Model Fan qty CT-1 Marley Aquatower 495B Table 6.3: Cooling Tower Cells Capacity HP VFD Flow EWT LWT tons 7.5 Y 450 gpm 98 F 85 F The cooling tower modulates the fan speeds equally in order to maintain a fixed condenser water supply temperature of 72 F. Based on our observations, there are many instances in which the tower fans are operating at 100% capacity, but are not able to meet the set point. The trend data below clearly shows that the target temperature is not met, even though the fans are operating at full capacity % % % % CWST CT Fan Spd (%) 70.00% 60.00% Outdoor Air Temperature ( F) Figure 6.3: Cooling Tower Fan Speed and Supply Temperature Trends This data indicates that the tower may be undersized. However, on-site observation revealed that the tower fill is significantly scaled and may have significantly degraded the heat transfer ability of the tower. This scaling would explain why the tower is unable to meet the desired set point. Table 6.4: Condenser Water Pumps 50.00% Mark Model Flow Head Motor HP VFD P-3 Armstrong Series x4x8 450 GPM 40 ft 7.5 N P-4 Armstrong Series x4x8 450 GPM 40 ft 7.5 N December 31,

23 The condenser water pumps are fixed-speed and therefore cycle a constant flow-rate through the cooling towers and chiller s condenser barrel. There is a bypass valve in the condenser water piping that, according to the control sequences, modulates in order to maintain a 5 F temperature difference between the CW return temperature and the tower fan set point. This valve is not monitored via the building control system, but did not appear to be modulating during any of our on-site visits. Heating The heating hot water (HHW) system consists of one boiler and two constant-speed primary pumps in a lead/lag configuration. This hot water is distributed to reheat coils in the VAV boxes throughout the building. Figure 6.4: Heating Hot Water Boiler (left) and Hot Water Pumps (right) A summary of the hot water system equipment specifications is provided below. Table 6.5: Boilers Mark Model Efficiency Input Capacity Output Capacity B-1 Raypak H9-2002B 84% 1,999 MBH 1,679 MBH Table 6.6 Heating Hot Water Pumps Mark Model Flow Head Motor HP VFD HWP-1 Unknown Illegible Nameplate 60 GPM 70 ft 3 N HWP-2 Unknown Illegible Nameplate 60 GPM 70 ft 3 N December 31,

24 Air Distribution Conditioned air is circulated through the library using five Governair air handling units (AHUs). The AHU specifications are as follows. Mark Model Table 6.7: Air Handling Unit Information Air Dist. Type Supply Fan Hp SF VFD? Return Fan? RF Hp Econ? Min OSA AHU-1 RSA-02-E Variable 15 Y Y 5 Y 20% AHU-2 RSA-02-E Variable 15 Y Y 5 Y 20% AHU-3 RSA-02-E Variable 15 Y Y 5 Y 15% AHU-4 RSA-02-E Variable 7.5 Y Y 2 Y 15% AHU-5 RSA-01-E Constant 2 N N N/A Y 20% Figure 6.5: AHU-1 Air handling units 1 4 all have chilled water valves only. Hot water is provided for reheat at the variable air volume (VAV) boxes as needed. The fans in each air handling unit are automatically controlled to maintain a fixed duct static pressure typically 1.2 inches of water (in/wc). Supply air temperature (SAT) reset controls adjust the SAT temperature set point from 55 F when the outdoor air temperature is over 75 F to a maximum of 65 F when the outdoor air temperature is less than 70 F. However, the trend data that we collected shows that the supply air temperature for each unit was constant throughout the monitoring period. The actual supply air temperatures that we measured, as seen below, ranged from 48.5 F to 57 F. December 31,

25 Supply Air Temperature ( F) kw Engineering AHU2 SAT AHU3 SAT AHU4 SAT AHU1 SAT Outdoor Air Temperature ( F) Figure 6.6: Supply Air Temperature Trend Data AHU-5 is the only constant-volume unit on site. This air handler serves only the conference room in the south end of the building. This unit has both chilled water and hot water coils in the air handling unit. The chilled water loop s differential pressure sensor is located at AHU-5, as it is the most remote air handler. Site Controls and Trending Capability The library s HVAC system is controlled by a Tridium-based NiagaraAX building automation system (BAS). This system monitors and controls all equipment both in the central plant and on the air-side of the system. This system includes a graphical interface that displays current set points, monitored points, and equipment operating status. Examples of these interfaces can be seen below. Figure 6.7: Air Handling Unit (left) and VAV (right) BAS Screens Of particular note in this screenshot and the one below are the values which are colored red, orange, or yellow. These colors indicate a box that is not communicating properly with the EMS, or that is not receiving space temperature readings from its associated thermostat. Site staff has stated that there are numerous controllers on the VAV boxes that no longer function and communication with the controllers in the air handling units is December 31,

26 interrupted regularly. We confirmed that many of the thermostats are not functioning properly or are not in the correct location to control their associated VAV boxes. As a result, the VAV dampers and reheat valves are operating based on incorrect input information from the space, and many set points have been set to manual override. This is typically leading to overcooling, particularly in the south end of the building. Trending Capabilities The current Niagara AX system is able to trend numerous data points on a time interval and change of value basis. In order to establish the baseline operation of the system, we trended the following data points for a period of four weeks: Table 6.8: Trended Points List Device/System Name Parameter Unit # of Points Sample Rate AHU1-5 CHWvalve Chilled water valve position % 5 15 minute AHU1-4 SF speed Supply fan speed % 4 15 minute AHU-14 RF speed Return fan speed % 4 15 minute AHU1-5 SAT Supply air temperature F 5 15 minute AHU1-5 RAT Return air temperature F 5 15 minute AHU1-4 SA static Duct static pressure in. w.c minute AHU1-5 Econo % Outdoor air damper position % 5 15 minute AHU1-5 OAT Outdoor air temperature F 5 15 minute Chiller CHW Flow Chilled water flow rate gpm 1 15 minute Chiller Chiller capacity Chiller capacity % 1 15 minute Chiller CHWbypass Chilled water bypass valve position % 1 15 minute Chiller CHWPspeed Chilled water pump speed % 2 15 minute Chiller CHWS_Temp Chilled water supply temperature F 1 15 minute Chiller CHWR_Temp Chilled water return temperature F 1 15 minute Condenser System CWS_Temp Condenser water supply temperature F 1 15 minute Condenser System CWR_Temp Condenser water return temperature F 1 15 minute Condenser System CTSpeed Cooling tower fan speed % 2 15 minute Heating hot water HHWS_Temp Hot water supply temperature F 1 15 minute Heating hot water HHWR_Temp Hot water return temperature F 1 15 minute December 31,

27 7. SUMMARY OF RECOMMENDED RCX MEASURES The following table provides a summary of the recommended RCx measures and the associated energy and monetary impacts. The measures identified include numerous repairs and control upgrades to the central plant and air-side systems. If all the measures are implemented, College of the Desert can expect to reduce their annual energy consumption by an estimated 375,568 kwh and 5,875 therms while reducing their peak demand by 21.9 kw. To determine these savings we calculated energy savings estimates and applied a 20% reduction factor to in order to ensure a conservative estimate. This reduction factor did not affect the calculated incentive, since the incentive is capped by the eligible project cost. We independently estimated the costs for these retrofits using cost databases such as RS Means, or based on direct quotes from College of the Desert s current contractors. The total estimated cost for all measures is $77,475. This cost covers the de-scaling of the condenser system as well as repairs and re-programming costs for BAS system components in both the air-side and central plant systems. Per program rules, incentives are capped at 80% of the eligible project cost. Based on the current savings, the incentive is capped. The cost-capped incentive for this project s electrical savings is $56,270. There are no gas incentives because the gas savings do not meet the SoCalGas incentive threshold. This incentive may change once SoCalGas participation in this project is clarified. The current incentive reduces the simple payback period for this project to 0.4 years. Since final incentive amounts are based on verified energy savings and costs, these numbers are preliminary figures only and may increase or decrease depending on the final verified figures. December 31,

28 Measure Number RCx-1 Measure Name Shut off HVAC During Unoccupied Hours Table 7.1: Summary Table of Investigated Energy Efficiency Measures 2 Peak (kw) Annual Energy, Cost and GHG Energy (kwh/yr) Energy (therm/yr) Annual Cost CO2 Emissions Avoided (tons/yr) Estimated (Pre-Retrofit) Estimated Measure Cost Potential 2013 Incentive Project Financials Net Measure Cost Simple Payback (yr) NPV MIRR ,818 5,397 $ 23, $ 8,280 $ 6,014 $ 2, $ 144,830 22% RCx-2 Air-Side Controls Retro-commissioning , $ 16, $ 47,745 $ 34,677 $ 13, $ 59,203 10% RCx-3 Repair/Restore Economizer Control 0.0 7,577 (382) $ $ 5,175 $ 3,759 $ 1, $ (623) 5% RCx-4 RCx-5 Optimize Condenser Water System and Cooling Tower Operation Optimize Chilled Water Pump VFD Control ,939 0 $ 6, $ 9,900 $ 7,190 $ 2, $ 29,671 13% 1.3 7,736 0 $ $ 6,375 $ 4,630 $ 1, $ (593) 5% SUB-TOTALS ,568 5,875 $ 47, $ 77,475 $ 56,270 $ 21, $ 232,488 13% Adjustment Factor 80% Assuming Electricity Cost : $ 0.12 /kwh Assuming Gas Cost : $ 0.75 /therm Assuming CO2 Reduction Equivalents : lbs CO2/kWh (for marginal energy use reductions) lbs CO2/therm RCx Incentives RCx Program Max Incentive Rates Cost Cap for total project 80% of costs Financials Rate Electric Peak Demand $0.00 per peak kw NPV Discount Rate for ROI 5% Electric Use $0.24 per kwh Finance Rate for MIRR 50% Gas $1.00 per therm Reinvestment Rate for MIRR 6% SCE Cost Split 91% $ 56,270 Capped at 80% of SCE Project Cost SCG Cost Split 9% $ - No cost savings beyond SoCalGas Value Added Services (no incentive) Notes on MIRR The Internal Rate of Return (IRR) allows comparison of the financial return of projects through their expected lives. Attractive projects have an IRR greater than the cost of money. Precisely, IRR is the discount rate which yields a Net Present Value of zero. The Modified IRR (MIRR) provides realistic values in all cases by applying an expected reinvestment rate for cash inflows. Prepared by David Gilliland (562) Measures with a simple payback period (SPP) without incentive of less than 3 years require implementation within 12 months per the terms and conditions listed in the SCE RCx Program Agreement. 2 SoCalGas may provide additional incentives up to $1 per therm saved ($5,875 based on current calculations), which will be confirmed at a later date. December 31,

29 7.1. Description of RCx Measures The following section describes the retro-commissioning measures at the MAL that we identified during the Investigation phase of this project. We calculated the energy savings using weatherbased spreadsheet calculations. To confirm the accuracy of our baseline calculation, we compared the total calculated energy consumption to the actual energy consumption of the building over the last 12 months. Our calculated model is calibrated to the total building electrical power consumption within a 4% margin of error, the total electrical energy consumption within a 1% margin of error, and the total gas consumption within a 1% margin of error. This precise calibration to the existing utility bills indicates that our model is a reasonable representation of the current building operations. Table 7.2, below, shows the comparisons between our simulation results and the electrical calibration data. Table 7.2: Energy balance showing comparison of baseline modeled data to actual billing data Loads Calculations kw Each Peak Contrib Peak Load (kw) Hours/ Day Days/ Year Hours/ Year Utilization Energy Use (kwh/year) % Subtotal (kwh) % Lighting 159, % Interior Lighting Sq ft Density ( kw ea. All spaces 1 41, , , % Exterior Lighting Estimated kw kw ea. All Exterior 1 41, , , % Plug Loads 92, % Office Space Sq ft Density ( kw ea. Computers and Equipment 41, , , % Refrigeration No Refrigeration - 0.0% - 0.0% HVAC & Ventilation 674, % AHU Ventilation Count kw ea. VAV From Bin Simulations 1 Model , % CAV From Bin Simulations 1 Model , % Chillers Count kw ea. From Bin Simulations 1 Models , % Chilled Water Pumps Count kw ea. From Bin Simulations 1 Model , % Cooling Tower Fans Count kw ea. From Bin Simulations 1 Model , % Condensing Water Pumps Count kw ea. From Bin Simulations 1 Model , % Boiler Pumps Count kw ea. HWP 1 Model , % Other Loads - 0.0% Other Equipment kw ea. Total Electrical kw 926, ,621 Actual Peak Demand to Date % Actual kwh to Date: 920, % Gas Consumption Boilers Count Sq. Ft. Density Units Energy Use (therms/yr) Boilers 1-14, % DHW Heaters 1 41, kbtu/sf 3, % Total Electrical 18,221 Actual Therms to Date: 18,455 99% December 31,

30 Average Space Temp, F kw Engineering RCx-1: Shut off HVAC During Unoccupied Hours Annual Payback Peak Period (kw) Electricity (kwh) Gas therms/yr) Annual Cost Potential Utility Incentive Net Measure Cost MIRR Simple Payback (years) ,818 5,397 $23,689 $6,014 $2,266 22% 0.1 Initial Observations and Measurements Currently, the HVAC schedule in the BAS is set to maintain occupied space temperatures 24 hours per day. As a result, the library s chiller, cooling tower, and air handling units must all operate constantly in order to meet these set points. Site staff have manually input this 24/7 schedule for two reasons: they have had issues starting up the chiller in the morning, and because during the hot summer months, it is difficult to cool the building down in the morning if it is allowed to heat up over night. The following graph shows that the return air temperature from the building is consistent even during nighttime operation. This data clearly shows that the occupied space temperatures are maintained 24 hours per day. Keeping the building cool, even when it is unoccupied, is a significant and unnecessary use of energy. Average Space Temperature vs. Time of Day Time of Day Figure 7.1: Trend data showing consistent space temperature throughout all hours of the day Based on our conversations with facilities staff during our site visits, we ve determined that many if not all of the chillers previous issues which were affecting its start-up reliability have been addressed. These have included a replacing a failed expansion valve, malfunctioning controllers, and the compressors; and repairing communication issues between the chiller and BAS. Site staff did note, however, that they still experience a low condenser flow alarm during some startups. We have identified a number of issues with the condenser water system, which are discussed in RCx-4. We believe that implementing our recommendations in this measure will alleviate the condenser water flow issues during chiller startup. Additionally, though site staff have stated that they are unable to cool the building during the day if it is allowed to heat up at night, we note that last year during the summer months before the recent renovations to the building the site had significantly lower nighttime energy consumption due to the HVAC equipment turning off. We also note that during the trending December 31,

31 period, the peak chiller load was 50%, even though the outdoor air temperature was as high as 109 F. Based on this observation, and rule of thumb sizing calculations, the chiller is oversized for this site and should provide sufficient cooling capacity to cool down the building in the morning. Figure 7.2, in the Recommendations section below, confirms the peak chiller load of just over 100 tons. As a result of these observations, we believe that any morning cool down issues are the result of problems in the air-side systems. Our site visits and trend data collection confirmed that problems with the air-side controls are affecting the HVAC system s ability to effectively cool the space. We expect that repairing and optimizing the air-side systems, which we are proposing in RCx-2, will allow the site to shut down the HVAC, or at least relax the space temperature set points, during the nighttime. Recommendations We recommend implementing this measure in conjunction with RCx-4: and RCx-2: Air-Side Controls Retro-commissioning. As stated above, our findings indicate that implementation of these measures should increase the startup reliability of the chiller and increase the morning cool down effectiveness, making the implementation of RCx-1 more feasible. Implementing this measure may be as simple as programming the schedule within the BAS with occupied and unoccupied schedules. During the occupied schedule, the space temperature set points will be set at comfortable levels. We typically recommend a 74 F cooling set point and a 68 F heating set point. To ensure that the building is at a comfortable temperature by the time staff arrives in the morning, we recommend programming the occupied schedule to begin 1-2 hours before the staff typically arrives. Once the building is closed for the night or over the weekend, the BAS should be programmed so that the HVAC system goes into an unoccupied mode. In unoccupied mode, the space temperature set points should be set back to a cooling set point of 85 F and a heating set point of 55 F. Relaxing the space temperature set points during the unoccupied hours will reduce the load on the heating and cooling systems in many cases to a point where they can be shut off entirely. Programming the BAS so that the HVAC systems are off when the building is unoccupied will yield significant energy savings for this site. Since there is still apprehension about the reliability of starting up the chiller in the morning, we also recommend re-commissioning the chiller to ensure that it can properly and reliably start-up and shut down on a daily basis. This re-commissioning process will involve: - Testing the operation of all mechanical components in the chiller - Identifying and repairing any communication issues between the chiller and the EMS - Ensuring that all internal controllers are functioning correctly - Investigating any fouling or clogging of the coils that may be affecting the water flow rates. We suggest that site staff, a representative from the chiller manufacturer, and the controls contractor all conduct their analysis of the chiller s operational status in tandem to assure that all possible issues are identified and addressed. Once the chiller is reliably starting up in the morning, we recommend that site staff adjust the occupancy schedule within the current building automation system based on our recommendations above. December 31,

32 Cooling Load (tons) kw Engineering Basis of Energy and Costs To estimate energy savings, we modeled the baseline and post-retrofit systems using outdoor air temperature-based bin simulations. The baseline simulation models the existing chilled water and air-side systems using one month of trend data. The measured data includes airflow, supply and return air temperatures for each air handling unit, as well as chilled water temperatures. During the monitoring period, the HVAC equipment was conditioning the space 24 hours per day. Site staff confirmed that they run the chiller and condition the space all night because the chiller has failed to start-up in the past, causing major space conditioning issues. We believe that our baseline energy model is reasonable because the inputs are based on mechanical specifications and trend data, and because the baseline energy consumption is calibrated to within 4% of the building s peak demand, 1% of the annual energy consumption, and 1% of the annual gas consumption based on the past year s energy bills. To model the post-retrofit case, we adjusted the HVAC operating schedule so that there is minimal (25%) space conditioning between the hours of 8:00 pm to 6:00 am during the week or on either of the weekend days. We also reduced the weekend operating hours during the occupied period by 50% because the north half of the building is closed on weekends. Currently, the weekend building loads are nearly identical on the weekend and weekdays, as seen below. This load should decrease in the post-retrofit system once the temperature set points are relaxed in the unoccupied half of the building Average Weekday vs. Weekend Cooling Load Avg. WE Load Avg. WD Load Time of Day Figure 7.2: Trend data showing weekday and weekend cooling loads December 31,

33 As a result of implementing occupied and unoccupied HVAC scheduling, the total annual energy consumption of the chiller, cooling tower, pumps, air-handling unit fans, and heating hot water boiler all decreased. This measure did not result in a reduction in the building s peak power consumption because the building is occupied during the full DEER peak period and will therefore see no reduction in power consumption during this time. The primary cost of this measure is the labor required to assess any remaining issues with the chiller and to re-calibrate any sensors that maybe malfunctioning in the system. Additional labor will be required to re-program the BAS to implement the desired nighttime set back temperature, schedule. We estimated that 40 hours of labor would be required, at a rate of $138 per hour, to conduct the testing and to re-program the BAS. Measurement and Verification Plan The following table summarizes the proposed M&V activities for this measure: Measure Size Verification Type Pre-Install Duration Post-Install Duration Medium (IPMVP Applies) Option A: Retrofit Isolation - Key Parameters 4 weeks 2 weeks We collected the following data points during the RCx investigation and will collect the same points after implementation to verify the savings. Measurement System Logger Units Return Air Temperature AHU1-5 BAS F Supply Air Temperature AHU1-5 BAS F AHU Supply Fan Speed AHU1-5 BAS % % Chiller Capacity Chiller BAS % CHW Pump Speed CHWP BAS % CT Fan Speed CT BAS % CHWS Temperature CHW BAS F CHWR Temperature CHW BAS F The energy savings will be verified based on evidence, documented by trend data, that the space temperature is allowed to increase during unoccupied hours, and that the HVAC systems are off during those unoccupied hours. We will also review the programmed building occupancy schedules to ensure that the building is scheduled to be unoccupied at night. If the trend data does not confirm the simulation results, we will adjust the operating schedule to match the collected trend data. December 31,

34 RCx-2: Air-Side Controls Retro-commissioning Peak Period (kw) Electricity (kwh) Annual Gas therms/yr) Annual Cost Potential Utility Incentive Payback Net Measure Cost MIRR Simple Payback (years) , $16,547 $34,677 $13,068 10% 0.8 Initial Observations and Measurements Based on our site visits and observations from the BAS, there are a number of issues with the site s control over their air-side systems, including the air handling units (AHUs) and the variable air volume (VAV) boxes. The VAV control issues appear to be predominantly located in the south half of the building. During the site visit we tested a sample of VAV box and AHU controls to identify the functionality issues. The most common issues that we observed were: - VAV Damper positions are not reporting properly. As seen in the EMS screenshot below, the damper position is reading 0.0% but the airflow is 1,034 cfm. This is seen on a number of VAV boxes in the library. During our site visits we tested the dampers and found that most of them would open or close based on a manual override of the set point within the BAS. This indicates that the damper mechanisms are working properly, and that the wiring is connected, but that there is an issue with the control methodology that is preventing proper damper operation. - VAV and AHU control points are losing communication with the BAS. During our site visit we observed that numerous points, including duct temperatures, damper position, airflow set points, and the hot water valve position, would regularly lose communication with the BAS and fail to update. These lapses in communication are indicated by a yellow, orange, or red highlighted value, as seen in the BAS screenshots below. Figure 7.3: Malfunctioning VAV Boxes December 31,

35 - Although our tests revealed that most VAV boxes were able to receive manual overrides from the BAS, one of the VAV boxes we tested did not respond to any commands at all. This may indicate a complete failure of the VAV controller, a mechanical issue that is physically preventing the box from responding to commands from the BAS, or bad wiring. In the VAV box that we observed to be completely unresponsive, it appears that the wiring may be partially disconnected, as seen in the photo below. This and possibly other units on site will likely require mechanical repairs and/or replacing the controller and wiring, but the main issues appear to surround the programming/controls. Figure 7.4: VAV Controller with Disconnected Wiring - A number of VAV boxes have no communication with their associated thermostats either. The thermostat should be measuring the temperature in the space, and the VAV box should adjust its damper position and hot water valve in order to meet the desired space temperature set point. However, in a number of cases we identified that the thermostat controlling a VAV box was nowhere near the zone that the VAV was conditioning, or there did not appear to be any thermostat controlling the unit at all. Without a thermostat to measure space temperature and report this information to the VAV box, the BAS cannot know when to adjust the damper and valve position in order to maintain the set point. As a result, we observed that a number of areas are being overcooled (space temperatures of 65 F), the VAV dampers are open more than they need to be, and the reheat valves are opening unnecessarily (many reheat valves were at 100% open, even though the outdoor air temperature was nearly 100 F). Figure 7.5: Three Thermostats in Close Proximity December 31,

36 - The chilled water valves on AHU-1 and AHU-2 were malfunctioning during our site visits. During the first visit, we observed that the chilled water valve on AHU-2 was operating backwards opening when less cooling was needed, and closing when more cooling was needed. This poor control of the chilled water valve is resulting in cooler supply air temperatures than the rest of the AHUs, which in turn results in increased re-heat at the VAV box level. During our second site visit, the chilled water valve on AHU-1 was broken and not responding to BAS control. Finally, site staff noted that the building cannot cool down fast enough in the morning if the building HVAC system does not stay on all night. We suspect that restoring proper VAV control, particularly reducing the amount of simultaneous heating and cooling, will allow the HVAC system to more effectively cool the space. This will allow for implementation of other energysaving measures, such as RCx-1:. Recommendations Though we were able to identify a number of issues in the sample of air-side equipment that we inspected, a further inventory of all issues in the air-side control system is required. We recommend that the site s controls contractor, Dynalectric, inspect each of the 61 VAV boxes and 5 AHUs to determine what issues, if any, are preventing proper communication between the mechanical equipment and the BAS. Specifically, we recommend that Dynalectric take the following actions for each VAV box and AHU: - Visually inspect the mechanical equipment to identify any broken linkages, stuck dampers, or malfunctioning control valves. - Check each electromechanical controller to determine if it is properly wired and if it communicating properly with the BAS. - Next, test the functionality of the dampers and the calibration of the temperature sensors by comparing the EMS readings to real-world temperature and airflow measurements. - Confirm that the thermostat controlling each VAV box is located appropriately and is functioning properly. The thermostat should be placed in the vicinity of the supply air grill for the VAV that it is controlling. In order to fix the above problems, we recommend: 1. Making any necessary repairs to the mechanical and electrical systems (dampers, valves, wiring, controllers, etc.). 2. Next, re-locate thermostats or install new thermostats if necessary so that the thermostats are providing accurate space temperature data to each of the VAV boxes. Once these issues have been addressed, the BAS should be able to properly control the VAV boxes. Once the VAV boxes and AHUs are repaired and communicating properly with their thermostats and with the BAS, we expect the temperature profile within the library to equalize to a comfortable temperature throughout. The current space temperatures are quite low 65 F in some cases and 69 F on average. We anticipate that restoring control to the VAVs will result in an overall increase in the average space temperature to 74 F. With this increased set point and proper control over the VAVs, the VAV dampers should close more frequently during cooling hours. Closing the dampers will allow the air handling units supply fans to slow down while still maintaining the duct static pressure set point. December 31,

37 Additionally, restoring control of all VAV boxes should reduce the amount of time that the reheat valves are open, since the cooling capacity can be controlled by changing the airflow, rather than by reheating the air. Reducing this simultaneous heating and cooling will reduce the boiler consumption and reduce the load on the cooling coils, since the amount of heat being added to the space will decrease. We also note that proper control over the air-side systems will allow for the implementation of more advanced energy-saving measures in the future. These measures include control improvements such as a duct static pressure reset, which would reduce the static pressure set point and slow down the supply fans even further during times of low cooling load. We are not recommending these more advanced techniques as part of the scope of this project, however, as we believe the most critical goal of this project is to re-instate proper control of the air-side systems before implementing complicated control algorithms. Basis of Energy and Costs The baseline bin simulation for this measure uses actual supply fan speeds, supply air temperatures, and return air temperatures, which we trended for one month, to model the air handling unit operation and to determine the zone load. To model the post-retrofit case, we used the same zone load that was calculated in the baseline model. However, instead of using trend data to define the fan speed and supply air temperature, we calculated these values based on the proposed control method. Specifically, we modeled the supply air temperature in the following manner: - The supply air temperature set point is calculated based on the current supply air temperature reset strategy in this building s current sequence of operations. This strategy resets the supply air temperature between 55 F when the outdoor air temperature is greater than 70 F, and resets the supply air to 65 F if the outdoor air temperature drops below 50 F. - Using this calculated supply air temperature, we then calculated the required fan speed. We calculated the airflow (and thus the fan speed) using the following standard cooling load formula. We assumed that the zone load would remain the same as in the baseline case, and used an average return air temperature (RAT) of 74 F. As a result of revising the space temperature, airflow, and supply air temperatures to reflect proper operation of the air-side systems, the energy consumption of both the air-side systems and water-side systems decreased. The air-side energy dropped because air handler fan energy will be saved when the VAV dampers close down. The central plant energy consumption decreased because the overall load on the cooling coil decreased. Though the zone load is the same, the coil load decreased because less re-heat is needed when the dampers function properly. As a result, the load on the coil more closely matches the zone load, and the energy consumption of the chiller plant equipment decreases. To estimate the costs, we assumed that Dynalectric would investigate each of the building s 61 VAV boxes and the 5 air handling units to identify issues. We assumed the process of assessing and repairing any control issues would take 3 hours per each of the 66 devices. We also assumed that 10 new programmable thermostats would be required, and two new December 31,

38 automated chilled water valves. We assumed a labor rate of $138 and collected materials costs from the RS Means cost database. Measurement and Verification Plan The following table summarizes the proposed M&V activities for this measure: Measure Size Verification Type Pre-Install Duration Post-Install Duration Large (IPMVP Applies) Option A: Retrofit Isolation - Key Parameters 4 weeks 4 weeks We monitored the following points during this investigation phase, and plan to monitor the same points during the implementation phase in order to confirm the results: Measurement System Logger Units Supply fan speed AHU1-5 BAS % Supply air temperature AHU1-5 BAS F Return air temperature AHU1-5 BAS F If the fan speeds or air temperatures that we observe during the post-implementation monitoring differ dramatically from the values that our model predicts, we will adjust the model to match. We will also trend the following points from a sample of five VAV boxes during the postimplementation period to confirm that the dampers and valves are operating properly. Measurement System Logger Units Damper Position Discharge Air Temp Reheat Valve Position VAV Boxes (5) VAV Boxes (5) VAV Boxes (5) BAS % BAS F BAS % December 31,

39 OAT - RAT ( F) Outside Air Damper Position (%) kw Engineering RCx-3: Repair/Restore Economizer Control Peak Period (kw) Annual Electricity (kwh) Gas therms/yr) Annual Cost Potential Utility Incentive Net Measure Cost Payback MIRR Simple Payback (years) 0.0 7,577 (382) $589 $3,759 $1,416 5% 2.4 Initial Observations and Measurements Each of the library s five air handling units has outdoor air dampers with mechanically-controlled actuators. These dampers are controlled by the building automation system to open and close based on the outdoor air temperature. During times when the weather is hot, the dampers should be controlled to bring in only the minimum amount of outside air that is required to ventilate the space. However, when the outdoor air is cool, more air can be brought in to cool the space, rather than using chiller energy to do so. Based on the building s current control sequences, the dampers are supposed to open to 100% whenever the outdoor air temperature is 3 F colder than the return air temperature. The trend data that we collected from the individual air handling units, shown in the graph below, indicates that even when the above control scenario is met, the outdoor air dampers remain in their minimum position. The highlighted portion of the graph shows the temperature range where the dampers should have opened to bring in cool outdoor air OAT - RAT ( F) and Economizer Position (%) OAT - RAT ( F) MAL AHU1 Econo (%) Economizer Range Air Handler Economizers: Economizer systems take advantage of favorable weather conditions to reduce mechanical cooling loads by introducing cool outdoor air into a building. The term free cooling is used to describe savings achieved from a properly working economizer. An economizer consists of dampers, sensors, actuators, linkages and controls that work together to determine how much outside air to bring into a building. In mild climates, economizers save energy by using outside air to supplement mechanical cooling equipment to cool the building. When economizers are properly installed and maintained, they can significantly reduce mechanical cooling in certain climates. Economizers not only save energy, they also decrease wear on airconditioning equipment and increase indoor air quality /20/13 8/22/13 8/24/13 8/26/13 8/28/13 8/30/13 9/1/13 Date Figure 7.6: Current Outdoor Air Damper Positions We investigated the outside air dampers and the control system to determine why the economizer functionality was not working. During our second site visit, we input manual overrides into the BAS to tell the dampers to open to December 31,

40 100%. All of the AHU dampers responded properly to this manual override. This indicates that there are no communication issues between the AHU controllers and the BAS (with regard to damper control) and that the damper actuators are all functioning properly. The issue preventing proper damper control, therefore, is most likely a flaw in the current control algorithms. Recommendations We recommend that Dynalectric investigates the current control programming for the economizer cycles. The intent of the programming, which is listed in the sequence of operations, is to open the outdoor air dampers if the outdoor air temperature is three degrees less than the return air temperature. If functioning properly, this should be an effective method for controlling the outdoor air damper. We therefore do not recommend making any changes to the control intent, only the execution of these control parameters. Alternatively, the outdoor air dampers could be controlled based solely on the outdoor air temperature. A typical economizer cycle is to open the outdoor air dampers to 100% any time the unit is in cooling mode and the outdoor air dry-bulb temperature is 70 F or below. This more simplified control mechanism should provide equal performance to the current sequence of operations, and since it relies on fewer sensor inputs, may prove to be more reliable. We also note that, as mentioned in RCx-2, above, the current space temperatures are abnormally cold. The economizer control is based on the difference between the outdoor air and the return air. One expected result of implementing RCx-2 is that the overall return air temperature from the spaces will increase. This will in turn allow for additional economizer hours, resulting in an overall decreased load on the chiller. Basis of Energy and Costs We calculated the energy savings for this measure using a weather-based bin simulation. This simulation was implemented in succession with the simulation for RCx-2. Using the RCx-2 simulation as a baseline, we adjusted the maximum outdoor air intake for each air handling unit from the minimum value to 100%. Our model estimates that the outside air dampers will open to 100% any time the outdoor air temperature is below 74 F. We also implemented a cooling lockout so that any time the outdoor air temperature is below the 60 F bin, the chiller, cooling tower, and all hydronic pumps shut off. We applied these changes to all air handlers. Energy savings for this measure are achieved because the load on the cooling coils will be lower once a higher percentage of the cool outdoor air is used during the economizer hours. As a result, the water-side load will decrease, and in some cases the chiller, cooling tower, condenser water pump, and chilled water pump may shut off entirely. We estimated that it would take Dynalectric 25 hours to test and repair the economizer operations for all five air handling units, at an assumed labor rate of $138. We did not factor in any materials cost to this measure since our observations confirmed that the mechanical aspects of the outdoor air dampers are functioning properly. December 31,

41 Measurement and Verification Plan The following table summarizes the proposed M&V activities for this measure: Measure Size Verification Type Pre-Install Duration Post-Install Duration Small (BOA Tool does not apply) Option A: Retrofit Isolation - Key Parameters 4 weeks 2 weeks We collected the following data points during the RCx investigation and will collect the same points after implementation to verify the savings. Measurement System Logger Units Outdoor air temperature Outdoor air damper position Supply air temperature Return air temperature AHU1-5 BAS F AHU1-5 BAS % AHU1-5 BAS F AHU1-5 BAS F Supply fan speed AHU1-5 BAS % Chiller Capacity CH1 BAS % We expect that any time the outdoor air temperature is below 74 F and above the cooling lockout set point, the outdoor air dampers will open to 100%. As a result, the coil load will decrease and we should observe a decrease in the chiller capacity during these hours. If the post-implementation data does not correspond to our energy model, we will adjust the outdoor airflow and resulting coil load based on the collected data. December 31,

42 RCx-4: Optimize Condenser Water System and Cooling Tower Operation Peak Period (kw) Annual Electricity (kwh) Gas therms/yr) Annual Cost Potential Utility Incentive Net Measure Cost Payback MIRR Simple Payback (years) ,939 0 $6,123 $7,190 $2,710 13% 0.4 Initial Observations and Measurements During our site visits, and with the assistance of Dan Earley and Advanced Chemical Technologies (ACT), we identified a number of deficiencies in the current cooling tower and condenser water system. Scaling of Heat Transfer Surfaces First, we identified significant calcium carbonate buildup, also known as hard water scaling, on the cooling tower fill, as seen in the photo below. Scaling on the inner surfaces of a cooling tower reduces the effective heat transfer surface of the tower and thus reduces the capacity of the cooling tower. Using a borescope, ACT confirmed that there is heavy scaling within the cooling tower fill, which is altering the water flow and reducing the heat transfer effectiveness. ACT also found scaling on the air intake and air discharge, which is reducing the airflow capacity of the tower fans. This scaling is causing the cooling towers to operate at a severely reduced capacity. Dan noted that the site currently uses ACT s polymeric dispersion treatment to treat the tower water, and this method has been working on the site s other cooling tower. However, site staff confirmed that the scale built up before the ACT treatment process was implemented, and the scale was never removed. The treatment system can prevent new scale from forming, but will not remove the scale that is already built up. A physical cleaning and scale removal must be performed in order for the tower to return to full effectiveness and for the current water treatment system to prevent future scale build-up. Figure 7.7: Scaled Cooling Tower Fill December 31,

43 The result of this scaling is that the fans have to work harder in order to provide the same cooling capacity as a tower with clean heat transfer surfaces. The baseline trend data, seen in the graph below, shows that the cooling tower fans frequently operate at 100% speed, regardless of the cooling load or outdoor air temperature, and are still not able to meet their set point. Additionally, minerals from improperly treated cooling tower water can also scale the condenser coils within the chiller. This scaling reduces the heat transfer effectiveness within the condenser, as it does in the tower. During our site visit we observed that the condenser approach (the difference between the refrigerant s saturated condensing temperature and the leaving condenser water temperature), was at least 5 F. The site s chiller model, when new, should be capable of an approach of 1-2 F. The lower approach indicates greater heat transfer effectiveness between the refrigerant and the water in the condenser barrel MAL CT1aSpeed (%) CWRT OAT 0 9/3/2013 0:00 9/4/2013 0:00 9/5/2013 0:00 9/6/2013 0:00 9/7/2013 0:00 9/8/2013 0:00 9/9/2013 0:00 Figure 7.8: 100% CT Fan Speed (left), Condenser Approach (right) Open all Throttling/Balancing Valves in Condenser Water Line During our site visits we noticed that the condenser water flow rate is restricted in two locations. The condenser water return lines to the cooling towers are both throttled down to approximately 75% open, and the balancing valve on condenser water pump #2 is closed to 85%. Photographs of both of these flow restrictions are provided below. During our site visit, with pump #1 operating, we found that the pressure differential across the pump was 44 ft, which is 10% higher than the pump s rated operating point. Based on the pump curve, the pump is operating at 400 gpm, not 450 gpm as designed. This flow would be further restricted whenever CWP #2 is staged on as the lead pump, as the balancing valve is adding further restriction to the line. Sometimes the condenser water return lines are throttled at the tower to prevent overflows. However, Dan Earley of ACT opened the valves and confirmed that there were no overflows as a result. December 31,

44 Figure 7.9: Condenser Water Throttle Valve (left), CWP #2 Balancing Valve (right) Based on typical engineering rule of thumb, there should be 3 gpm of condenser water flow per ton of cooling. According to the mechanical schedule, this site s system only has 2.25 gpm of condenser water flow per ton. Therefore, further reducing the flow rate using throttling valves could have a seriously detrimental effect on the chiller performance, and may be partly responsible for the low condenser flow alarms that have been causing chiller start up issues, as mentioned in RCx-1:. Fixed Condenser Water Temperature Set Point Improving the tower performance via de-scaling and increasing the water flow should allow for lower condenser water supply temperatures. Currently, the tower operates with a fixed condenser water supply temperature set point of 72 F. However, the Turbocor compressors in the site s McQuay chiller operate best with lower condenser water temperatures down to 65 F. Due to the high temperatures in this climate zone the tower will not always be able to achieve a 65 F condenser temperature, but our model shows that there are times when this set point should be achievable. Any reduction in the condenser water supply temperature will yield a significant reduction in the chiller s compressor consumption. Recommendations In order to optimize the condenser water system and maximize the cooling tower capacity, we recommend the following actions: 1. Implement all of ACT s recommended corrective actions on the condenser system, which are summarized from their proposal as follows: Pressure wash cooling tower air intake and air discharge leading edges to remove accumulated debris. Remove distribution pan covers and clear nozzles of any obstructions. Flush debris from tower basin. Perform system de-scale utilizing inhibited sulfamic acid solution. Spray manifolds will need to be temporarily installed to ensure proper distribution of cleaning solution over the intake areas of the fill pack. This can be accomplished while the system is running in normal operation, and should not harm any system components. The bonus by cleaning the towers this way will also allow the cleaning of the shell and tube condenser on the McQuay chiller at the same time. December 31,

45 Adjust flow distribution valves and balance water return to tower distribution decks. This can be done while the system is in normal operation. (Opened valves fully on 9/30) Replace chemical pump injector. (Chemical pump and injector was replaced on 10/7) Replace cracked conductivity probe on LMI DC conductivity controller. Coat brominator with fiberglass paint to provide protection. Clear clogged drains. 2. Since the current water treatment mechanism has apparently been working to prevent scale build-up on the cooling towers at the site s other central plant, we recommend continuing to use the same system. This system was likely not effective before since the scale buildup had not been physically removed. Once all heat transfer surfaces have been cleaned this system is expected to effectively prevent further calcium carbonate scaling. 3. We also recommend hiring ACT or another water treatment contractor to return to the site in regular intervals to conduct cleanings and to properly maintain the condenser water treatment system. This regular maintenance will ensure that the tower remains scale free in the future. 4. We recommend re-balancing the condenser water distribution system with the assistance of AMT or a separate test and balance contractor. The goal will be to ensure that the full design flow of 450 gpm is running through the system. We expect that achieving this flow will require fully opening all balancing valves and throttling valves in the condenser water system. Opening the valves will increase the condenser water flow rate and therefore increase the cooling effectiveness of the tower. 5. We recommend implementing a condenser water temperature reset strategy. This control method would monitor the outdoor air wetbulb temperature and adjust the condenser water supply temperature set point so that it is 2-3 degrees above the wet bulb temperature, with a minimum set point of 65 F. Alternatively, the set point could be fixed at 65 F, and allowed to float up if the set point is not achievable based on the outdoor air temperature. The goal of this recommendation is to achieve the lowest possible condenser water temperature. The efficiency of the site s McQuay chiller increases dramatically with lower condenser water temperatures. Implementing these recommendations will increase the cooling capacity of the existing cooling tower, and will therefore allow the system to achieve lower condenser water temperatures. The result of decreasing the condenser water temperature will be an increase in the chiller capacity and a resulting decrease in the chiller power consumption. Additionally, implementing these maintenance and controls measures may fix the low condenser flow issues during chiller startup, which is one of the issues that may be affecting the chiller s start-up reliability. Basis of Energy and Costs We determined the energy savings for this measure using a weather-based bins simulation. The simulation identifies the expected load on the cooling tower at each outdoor air temperature bin. To model the baseline, we collected one month of trend data of the cooling tower fan speeds. Using this data, we correlated the tower fan speed to the outdoor air temperature using a linear regression. We then used this regression analysis to estimate the tower fan speeds across all December 31,

46 outdoor air temperatures. We applied the same regression analysis to the condenser water supply temperature and return temperature data in order to correlate those temperatures to the outdoor air temperature as well. In the baseline model, we back-calculated the chiller s perceived condenser water supply temperature using the measured chiller load, condenser return temperature, and condenser water flow rate using the standard cooling capacity equation: The result of this calculation showed that chiller s perceived temperature is consistently higher than the actual condenser water supply temperature. This indicates, as expected, that fouling in the condenser barrel is reducing the heat transfer capacity of the system. This was also observed by the high approach temperature as seen in Figure 7.8, above. To model the post-implementation system, we re-calculated the condenser water system parameters. We used the same cooling tower load and condenser water flow rate that was used in the baseline system, as these parameters are not expected to change. The condenser water supply temperature in our post-implementation model is based on the following outdoor air temperature reset: OAT CWT 80 F 75 F 70 F 65 F Once the flow rate, tower load, and condenser water supply temperature are known, we recalculated the expected return temperature using the cooling capacity calculation referenced above. Finally, with the condenser water return temperature known, we calculated the required tower fan speed in order to achieve the previously determined condenser water supply temperature. The resulting calculation shows a decrease in the cooling tower fan consumption, as well as an overall decrease in the condenser water supply temperature. This decreased condenser water temperature increases the capacity of the chiller decreases the chiller s energy consumption. ACT submitted a cost estimate of $4,312 for the de-scaling procedure, but indicated that some additional labor hours from outside contractors might be required. We estimated 10 additional labor hours, at a rate of $138. ACT s quote included materials, so there are no additional material costs in our estimate. We also estimated 10 hours for Dynalectric to implement the proposed condenser water reset control strategy. December 31,

47 Measurement and Verification Plan The following table summarizes the proposed M&V activities for this measure: Measure Size Verification Type Pre-Install Duration Post-Install Duration Medium (IPMVP Applies) Option A: Retrofit Isolation - Key Parameters 4 Weeks 4 Weeks We collected the following data points during the RCx investigation and will collect the same points after implementation to verify the savings. Measurement System Logger Units Outdoor air temperature Cooling tower fan speed Condenser water supply temperature Condenser water return temperature BAS BAS F CT1-2 BAS % CW BAS F CW BAS F Chiller Capacity CH1 BAS % We will verify the energy savings using the collected post-implementation trend data. The trend data should show that the tower fan speeds and condenser water temperatures have decreased compared to the baseline when analyzed under the same loading conditions. If the trend data does not confirm the simulation results, we will adjust the fan speed profile and condenser water temperatures to match the trend data. December 31,

48 % kw Engineering RCx-5: Optimize Chilled Water Pump VFD Control Peak Period (kw) Annual Electricity (kwh) Gas therms/yr) Annual Cost Initial Observations and Measurements Potential Utility Incentive Net Measure Cost Payback Currently the primary chilled water pumps are equipped with variable frequency drives (VFDs). However, all of the pumps are set to operate at 100% speed whenever they are active, as is seen in the trend data graph below. Operating a VFD-controlled pump at 100% speed is a waste of energy. VFDs are not 100% efficient, so operating a pump at 100% speed with a VFD uses even more energy than a constant-speed motor would consume. If, however, the pump speed can be decreased, then significant energy savings could be realized. MIRR Simple Payback (years) 1.3 7,736 0 $895 $4,630 $1,745 5% CHW Bypass (%) CHWP Spd (%) OAT ( F) Figure 7.10: CHWP Speed and CHW Bypass Valve Position There is also an automatic bypass valve in the system which is used to vary the flow through the air-side systems, while maintaining a constant flow through the chiller. We believe that the intended control method is to adjust the valve in order to maintain a constant differential pressure in the loop. There is a differential pressure sensor at AHU-5, which is the furthest point in the loop. We have not been able to determine the specific control methodology, as no sequence of operations has been made available for this system. The readout on the differential pressure sensor, seen in the photo below, showed a negative differential pressure during our site visits, which indicates a malfunction in the system. With the differential pressure sensor not working, it is unclear how the system is determining the appropriate bypass valve position. December 31,

49 Figure 7.11: Chilled water loop differential pressure sensor reading ( PSID) The rated flow through the chiller is 300 gpm. Based on our measured differential pressure across the chilled water pump, and the observed constant-speed operation of the pump, the flow is currently constant at 300 gpm. However, the chiller specification sheets indicate that this chiller is capable of operating with a variable chilled water flow and a minimum chilled water flow rate of 250 gpm. Therefore, any time the flow rate through the airside system is between 300 gpm and 250 gpm, the variable speed drive could be used to modulate the flow instead of the bypass valve. Using the VFD to vary the flow by reducing the pump motor speed, rather than by using a bypass valve, will yield energy savings over the baseline system. Recommendations We recommend re-programming the BAS system to enable variable chilled water flow. McQuay confirmed that the site s chiller is capable of a variable flow rate, and the chiller specifications indicate a minimum flow rate of 250 gpm. As such, we recommend the following actions: Test the functionality of the current differential pressure sensor. Repair any identified issues, or replace the sensor if necessary. Set the loop differential pressure (dp) set point to 3 psig, which is the maximum pressure drop for AHU-5 the furthest air handling unit in the chilled water distribution loop. We confirmed this pressure set point using the site s mechanical drawings. Program the BAS so that the variable speed drive modulates the pump speed to meet the differential pressure set point. Since the minimum flow through the chiller is 250 gpm (83% of rated flow), the minimum VFD speed should be set to 83% as well. If the pump is at minimum flow and the loop differential pressure is still higher than the set point, then the bypass valve should be used to further reduce the flow through the air-side loop. December 31,