Improving the efficiency, occupant comfort, and financial well-being of campus buildings

Transcription

1 GHAUSI HALL ENERGY PROJECT REPORT Improving the efficiency, occupant comfort, and financial well-being of campus buildings ACE TEAM, ENERGY CONSERVATION OFFICE UC DAVIS FACILITIES MANAGEMENT

2 Executive Summary The Active Commissioning Enterprise (ACE) is a self-funding effort to leverage significant investment in campus building control systems over the past ten years and optimize building HVAC systems to eliminate energy waste. This report details the scope of the ACE pilot project in Ghausi Hall and its results. The goal of Existing Building Commissioning (EBCx) efforts like ACE is to make building systems perform efficiently while still meeting the current facility requirements and to provide the tools to support the continuous improvement of system performance over time. EBCx projects typically only address the operation of the existing equipment and include only minor capital investment improvements. The savings realized by EBCx efforts come as a secondary benefit to making the system operate efficiently as per design. The priorities of doing in-depth equipment commissioning remain safety, occupant comfort, and better system performance. Some of the measures taken to improve the building systems included upgrades to the HVAC controls hardware, improvements to the system schedule and sequences, standardization of temperature and ventilation setpoints, and integration of lighting occupancy sensors to ventilation controls. Additionally, we added variable speed motors to HVAC equipment, and installed a wind measurement station to allow for dynamic control of lab exhaust rates based on wind speed and direction. 2

3 Figure 1: Total Energy use at Ghausi Hall before and after project (area in red shows avoided energy use) The energy savings resulting from these efforts is shown in the table below. Weather Normalized Metrics Annual Energy Cost Before Project $207,000 Annual Energy Cost After Project $152,000 Annual Dollar Saved $44,100 % Reduction 22% This project was pilot effort for our in-house continuous commissioning services and process. The techniques utilized and the performance improvements implemented can now serve as a foundation for implementing similar projects in other buildings. It also helps us to set target energy use intensity (EUI) numbers for future projects with similar energy conservation measures. 3

4 Table of Contents Introduction 5 Analyze 7 Whole Building Baseline and EUI Benchmarking Building Data Compilation Identify 12 Data Analytics (Driving Zones, Outliers) Oil Check Fault Detection & Diagnostic Software Site Visits Develop & Implement 14 New Control Sequences New Setpoints and Control System Parameters Equipment Upgrades Utility Incentivized Upgrades (Motor Speed Control & Sensors, Air Rebalance, Dynamic Wind Control, DCV) Verify 19 Building Energy Model Automating Measurement & Verification Conclusion 21 4

5 Introduction Existing Building Commissioning is a systematic process for investigating, analyzing, and optimizing the performance of building s current systems by identifying and implementing low/no cost improvements and ensuring the building continues to perform well over time. This is a critical function because the requirements and use of the facility change with time and the operational efficiencies may degrade without active monitoring and intervention. Key benefits that demonstrate the value of the EBCx process: Improve building performance by saving energy and reducing operational costs Identify and resolve building system operation, control and maintenance problems Reduce or eliminate occupant complaints and increase tenant satisfaction Improve indoor environmental comfort and quality and reduce associated liability Extend equipment life-cycle Ensure the persistence of improvements over the building s life Assist in achieving LEED for Existing Buildings certification Improve the building s ENERGY STAR rating 5

6 This report describes the sequential phases in the EBCx process. Though the process is iterative and loops back to previous phases throughout the project, this report treats each step as sequential. The basic phases and the goals of each phase of the EBCx process are as follows: Analyze Identify Develop & Implement Verify Report Examine information from building s Utility Meters to understand the building s current use pattern Identify all potential building inefficiencies Develop solutions and improvements to improve identified building inefficiencies and Implement the developed solutions Measure and verify weather normalized savings Report savings, changes, lessons learned, and next steps to various stakeholders The rest of this project report will give details to each of these steps. 6

7 Analyze The Analyze phase, which can also be called the Planning phase, helped us develop the EBCx project goals for Ghausi Hall. It was also during this phase that we developed and reviewed the current facilities requirements and the Active Commissioning Plan. Defining the scope of work early on helped us to stay focused throughout the project duration. Items such as temperature, operating hours, lab requirements, and/or specialty needs were also discussed during this initial phase. A preliminary building benchmarking was conducted for different end uses using Energy Use Intensity (EUI) for comparison purpose (figure 2). This helped us uncover potential opportunities and also served as the baseline to measure the future performance improvement. A more involved building benchmarking was also performed to compare the performance of Ghausi Hall against other Lab buildings on Campus (figure 3). 7

8 Figure 2: Energy Benchmarking for Ghausi Hall for different end uses Ghausi Hall is primarily classified as a lab building and has an area of 66,462 sq.ft. The combined energy use for the year 2013 for Ghausi Hall was 14,289 MMBTU. Chilled Water, Electricity and Steam cost $45,764; $104,508; and $45,503 respectively calculated using standard campus utility rates of Chilled Water: 0.8 /kbtu, Electricity: 2.2 /kbtu and Steam: 1.1 /kbtu. The estimate that PG&E gave for the incentives available through this Statewide Partnership Project was documented to be $55, with an estimated $17,676/year of energy savings. 8

9 Figure 3: Benchmarking of Campus Buildings based on their Energy Use Intensity (2013) To reduce the energy use in Ghausi Hall, we needed to look at individual utility usage throughout the year as well as system level performance down to the zone level. We also analyzed seasonal variations in Energy Use (Figure 4). 9

10 Figure 4: Monthly Utility Usage in Ghausi Hall (Before and After) 10

11 At the system level, there are 5 air handlers that are used for ventilation and air-conditioning across the 3 floors of Ghausi Hall. The labs in the building are served by two air handling units which serve 100% outside air to these zones. The offices and other miscellaneous zones are served by another three air handling units. On initial screening of the lab zones, we found the Air Changes per Hour (ACH) rate ranging from 2 ACH to 20 ACH. We found zones both over-ventilated and under-ventilated. We found the load varied from weekdays to weekends (see graph below), but the base electric load was consistently high (more than 50% of the peak demand). Figure 5: Weekday and Weekend Electricity Use in Ghausi 11

12 Identify After familiarizing ourselves with Ghausi Hall in the Analyze stage, our team moved on to digging deep within the building to identify ways that we could improve its operation. We had three important tools that we utilized in this deep digging process: 1. Building checklist developed by Pacific Northwest National Laboratory (PNNL) 2. Site visits to check and verify the systems and interview the occupants 3. Review of equipment-level trends to see if any system doesn t look right The first tool was a comprehensive list of building checks developed by PNNL. Our team adapted this list to our own needs and added to it as we proceeded through the project, finishing with over 100 checks. By using this list our team has a tight and applicable process for quick and effective commissioning projects. We can also share this with others who are interested in finding deeper energy savings. The second tool we used for locating energy savings was conducting site visits. Going out in the field and getting our hands dirty unearthed some important findings. Our team left no stone unturned over multiple site visits that found us in the depths of the mechanical rooms, the roof of the building, and everywhere inbetween. An added benefit of these site visits was meeting the people that work and research inside the building. Through conversations and site visits we were able to learn things about the building that we couldn t have found from behind our desks. The third tool we used was trend data analysis collected by the building control system which helped us gain insights into equipment performance. To get an idea of the size and complexity of the system, here are some numbers for the control system at Ghausi Hall: Over 80 direct-digitally controlled zones 3 floors consisting of high-tech labs 12

13 7,734 data points (sensors, motors, actuators, and setpoints) These three main tools allowed our team to find a large volume of energy conservation opportunities that would eventually result in a significant decrease in building energy consumption and an increase in occupant safety and comfort. Here are some items our team identified as opportunities to save energy: Thermostat setpoints were irregular and held potential for standardization and optimization Laboratory & office ventilation rates were both above and below current Environmental Health & Safety standards Zones were ventilated during times of vacancy Equipment ran when nobody was in the building Exhaust Fans were running harder than they needed to during most weather conditions Outdated piping configuration allowed for bypass that wasted energy when units were off Control Sequences were not optimized for energy efficiency and comfort Outdated control equipment for Laboratories and other main HVAC equipment 13

14 Develop/Implement After our review of Ghausi Hall and identifying operation inefficiencies, our team started to develop solutions based on industry best practices, but customized to the specific needs of Ghausi Halls and its configuration. Many solutions were the result of a collaboration between the engineering team and UC Davis skilled control technicians and safety personnel. We also received help and guidance from cutting edge wind analysis engineers and energy efficiency consultants. Ideas transformed from whiteboard sketches to lines of code, and designs transformed from notepad sketches to installation of new pieces of equipment. The end result was nearly 20 different building improvements. Examples of some developed and implemented solutions are: Using a wind tunnel analysis and live wind speed and direction to dynamically determine optimal exhaust fan operation A building-wide control system upgrade to allow zone-by-zone customization New air flow stations and discharge air temp sensors to better monitor air flow and temperature in zones Air Handler 3-way valves replaced with 2-way valves to reduce system pumping energy Upgraded Lighting Control System to allow occupancy-based HVAC control Existing control sequences were optimized Brand new control sequences were developed to improve comfort and save energy Building zone box and lab controller air rebalance Below are a few graphs (Figures 6-10) that illustrate some of the developed and implemented energy saving solutions. 14

15 Figure 6: Reheat Lockout illustrates a programming change that prevented reheat valves from opening up when the units that served these valves were off. This wasted heating and pumping energy until it was fixed. Figure 7: New Equipment Schedule shows the old start and stop time for an air handler unit, compared to the typical occupancy profile (acquired through trended occupancy sensor data). There were many hours that it would run when nobody was inside the building. Our team gave the air handler unit a more intelligent schedule that still met the needs of the building occupants. This saved heating, cooling, and fan energy, and also decreased unit runtime which lengthens the lifespan of the unit. 15

16 Figure 8: Heating Hot Water Coil 3-way Valve Replacement shows the impact of replacing high bypass 3-way valves with 2-way (bypass eliminating) valves for air handler heating coils. By reducing bypass, both heating and pumping energy is saved within the building. The drop in minimum heating hot water flow is evidence of energy being saved through decreased bypass. Figure 9: Chilled Water Coil 3-way Valve Replacement shows the impact of replacing high bypass 3-way valves with 2-way (bypass eliminating) valves for air handler cooling coils. By reducing bypass, both cooling and pumping energy is saved within the building. The increase in building chilled water delta T is evidence of energy being saved through decreased bypass. 16

17 Figure 10: Demand Controlled Ventilation illustrates the impact of using occupancy sensors to limit HVAC ventilation for spaces when they are unoccupied. By using this strategy in every zone in Ghausi, heating, cooling, and fan energy was saved. Figure 10 shows the difference in AHU fan power for a weekend (less occupancy) and weekday (more occupancy). Here is an overview of the budgetary breakdown of the project: Materials: $128, Labor: $128,071 Consultants: $80,372 Additional Cx Engineering: $158,400 This project started in June of 2013, and ended in January of The work was coordinated with the building occupants via normal shutdown notification processes and some additional s. The most invasive work was the room pre-reads, investigations, and the control upgrades. Interruption was less than an hour for the investigations, and about a day for the control upgrades. Most labs if they needed to could continue working during the interruptions, but most elected to take a day off. After the installation of new sensors and equipment was completed, UC Davis engineers set to work on using the data gathered by the building meters and control system to measure and verify the effect of the change, as well as inform further tweaks to get more energy efficiency and performance gains from the building systems. 17

18 Figure 11: Wind Tunnel Study at Ghausi Hall to determine the minimum acceptable volume flow rate for each fan while maintaining adequate air quality, a 1:180 scale model of the Ghausi Building and nearby surroundings was constructed and placed in CPP s boundary layer wind tunnel. 18

19 Verify UC Davis M&V process aligns with the practices documented in International Performance Measurement and Verification Protocol (IPMVP) and American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Guideline 14, Measurement of Energy and Demand Savings. The before project time is called Baseline or Pre Implementation period. The after time is referred to as the Post Implementation or Reporting period. Regression analysis was conducted to correlate energy use with independent variables representing weather and time. A model is considered fit for use or calibrated when the statistical indices such as C v -RMSE and R 2 meet the set threshold. Savings are defined as the normalized baseline utility use minus the normalized reporting-period utility use. We used Typical Meteorological Year (TMY) weather data for normalization. We have used Hourly Chilled Water Use, Hourly Electricity Use and Daily Steam Used as the dependent variables for three baselines respectively. The result of our M&V process is presented in the table below. 19

20 Table 2: Results of Measurement and Verification for Ghausi Hall Energy Project Figure 12: Pre and Post Implement TMY model showing different utility savings 20

21 Summary This project allowed our team to create a repeatable, streamlined process for saving energy in future buildings on campus. In summary, it contained the following steps: Analyze: Review the building data and building characteristics to better understand the building. Identify: Determine building system inefficiencies and potential areas for improvement. Develop & Implement: Create solutions to the identified building system inefficiencies, and implement them within the buildings. Verify: Confirm that the implemented solutions are operating properly. Document each solution, as well as the buildings as a whole. Continuously monitor the building s operations to ensure maintained energy savings. Report: Evaluate savings from normalized baseline utility use and normalized reporting-period utility use. In reflecting on the project as a whole, our team came to the following high-level conclusions We created a new and effective process for analyzing and identifying energy saving opportunities in buildings that have already had the easy opportunities fixed. We have proven that our process and personnel are capable of achieving deep energy savings in buildings with complex needs (ie, laboratories) We have developed our own automated process for performing industry-compliant Measurement and Verification analysis. We can now easily calculate dependable, and transparent energy savings in a repeatable manner for any future building with adequate utility data availability. Our team plans to roll out our approach to almost every building on the UC Davis campus to achieve campus-wide energy savings. Some important lessons were learned during this project that will help shape and accelerate similar future projects. These lessons learned were: Collaboration with building occupants is imperative for the success of a building energy project Effectively communicating the team s success is almost as important as the success itself Organization and collaboration are the most important characteristics of a high-performing and complex project such as this one 21