Commercial Building Re-tuning: Overview and Key Operational Faults and Corrections

1. Commercial Building Re-tuning: Overview and Key Operational Faults and Corrections Srinivas Katipamula, Ph.D. Staff Scientist, Pacific Northwest National Laboratory Better Building by Design – 2011 February 10th, Sheraton Conference Center Burlington, Vermont

2. Presentation Outline • Learning Objectives • Definition of Retro-Commissioning and Re-tuning • Why Retro-Commission a Building? • Washington State Project Approach to Re-tuning • U.S. Department of Energy Project on Re-tuning • Overview of Re-tuning Training • Identifying Low-cost/No-cost Operational Faults Using the Re-tuning Approach • Common Operation Faults • Example Operational Faults • Results from Re-Tuning Buildings • Conclusions

3. Efficiency Vermont is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

4. Learning Objectives At the end of this program, participants will be able to: • Understand an overview of Commercial Building Re-Tuning • Understand Key Building Operation Faults and Their Corrections (These presentations will provide an overview of the re-tuning process including the difference between re-tuning and other similar approaches) • Describe the various steps in the re-tuning process • Identify targets that commonly yield significant improvements in operation and decreases in energy use and discuss how re-tuning can yield a “gold mine” in savings

5. Course Evaluations In order to maintain high-quality learning experiences, please access the evaluation for this course by logging into CES Discovery and clicking on the Course Evaluation link on the left side of the page.

6. Definitions • HVAC Retro-commissioning • HVAC Re-tuning • HVAC Re-commissioning • HVAC Continuous CommissioningSM • Monitoring-Based Commissioning • All processes above in part relate to setting up control systems to some known design configurations, verifying set points and adding control algorithms

7. Why Retro-Commission a Buildings?

8. Retro-Commissioning Literature A number of studies have shown that retro-commissioning buildings can lead to significant energy savings – 5 to 30% Cost of retro-commissioning varies between 0.1$/sf to 0.6$/sf Cost savings can range between 0.1$/sf to 0.75$/sf Simple payback ranging from 3 months to 3 years A number of the measures addressed by retro-commissioning relate to our inability to control the building operations

9. Why is Retro-Commissioning not Widely Used? • There is a perception that retro-commissioning can be expensive • It can be expensive, but typically has less than 3 year paybacks • There is a perception that measures addressed during retro-commissioning do not persist for a long time (>6 months)

10. Re-tuning can Fill the Gap Re-tuning can address both the cost and the persistence question Because re-tuning is implemented by leveraging information from building automation system and primarily targets operational problems, cost of implementation is significantly lower than retro-commissioning Because re-tuning costs a fraction of retro-commissioning, it can be periodically done to ensure persistence

11. Origins for Re-Tuning In 1990s several researcher organizations were developing automated fault detection and diagnostics (FDD) tools – the researchers found that the FDD tools can indeed be used for commissioning building systems Also, at the same time Texas A&M University was using a process called continuous commissioning to retro-commission existing buildings In 2000s monitoring-based commissioning was being applied at many California campuses

12. What is Re-Tuning? A systematic process to identify and correct building operational problems that lead to energy waste Implemented primarily through the building control system at no cost other than the labor required to perform the re-tuning process Includes small, low-cost repairs, such as replacing faulty sensors Includes identifying other opportunities for improving energy efficiency that require investment Might be thought of as a scaled-down retro-commissioning focused on identifying and correcting operational problems

13. Major Focus Areas in Re-Tuning Occupancy scheduling Discharge-air temperature control Discharge-air static pressure control Air-handling unit (AHU) heating & cooling AHU outside/fresh air makeup AHU economizer operation Zone conditioning Meter profiles Central plant

14. Purpose of Re-Tuning • Improve the building’s energy efficiency through low-cost and no-cost operational improvements (mostly control changes) • Identify opportunities to further increase the building’s energy efficiency • Identify problems requiring physical repair • Catch the big energy saving opportunities

15. Life Cycle of Retro-Commissioning/Re-Tuning Typical commercial building behavior over time Energy Consumption Periodic Re-tuning Ensures Persistence Continuous Re-tuning Maximizes Persistence Time

16. Washington State Re-Tuning Pilot Project

17. Large Commercial Buildings Project • Goal • Educate companies that large buildings can be re-tuned economically to save electricity • Teach the proper techniques and skills to perform re-tuning, and • Show that service providers can provide re-tuning as a service for a fee • Approach • Recruit 5 to 10 companies that provide HVAC services to commercial buildings to deliver re-tuning services and to help recruit customers • Each of the selected service providers are required to recruit at least 6 buildings for re-tuning • Use 10 to 20 of the buildings as training grounds for hands-on training of the HVAC service providers on how to perform re-tuning

18. U.S. Department of Energy Re-Tuning Project

19. U.S. Department of Energy Re-Tuning Training Outreach • Re-tuning Training was Originally Developed as part of a Project Funded by Washington State (www.retuning.org) • Extending Training Outreach Beyond WA State (www.pnl.gov/buildingretuning) • Organization with large building stock interested in getting trained in the re-tuning process • Train-the-trainer – secondary goal • Working with a number of organizations to recruit for both the above approaches

20. Online Interactive Re-Tuning Training • PNNL is also converting the training into an online interactive training • Role based training with help of learning management system • Modular • Interactive with ability to create abnormal conditions • Questions and answers at the end each module and at the end of the course • PNNL is also looking to automate identification of the no-cost/low-cost operational problems • To improve persistence and cost of retro-commissioning

21. Project Objective • Improve operational efficiency of the commercial building sector by transferring the skills to “re-tune” large commercial buildings • Training building operators and service providers in the general principles and practices of good energy management • Publicizing the results of the project to other building operators and HVAC service providers, who are not part of the training, and to customers to encourage widespread adoption of these energy-saving methods • Preparing case studies to quantify comfort impact and energy savings resulting from re-tuning

22. Overview of Re-tuning Training

23. Re-tuning Training • Training consists of two parts • Classroom training • 6 to 8 hours, limited to 20 to 25 people • Field training • 1 day to 3 days, depending on the size of the building • Limited to 4 to 8 people

24. Intent of Re-tuning Training “Tell me and I'll forget; show me and I may remember; involve me and I'll understand” Chinese Proverb Provide an in-depth training of the re-tuning approach Prepare the participating technicians for hands-on field training Provide an opportunity to ask questions and get clarification on any aspect of the re-tuning process

25. Six Primary Steps of Re-Tuning Collecting Initial Building Information: Basic building information Pre-Re-Tuning Phase: Trend-data collection and analysis Building Walk Down: Getting to know the building Re-Tuning: Identifying and correcting operations problems Post Re-Tuning: Reporting re-tuning findings Savings Analysis: Determining and reporting the impacts

26. Six Primary Steps of Re-Tuning Collecting Initial Building Information: Basic building information Pre-Re-Tuning Phase: Trend-data collection and analysis Building Walk Down: Getting to know the building Re-Tuning: Identifying and correcting operations problems Post Re-Tuning: Reporting re-tuning findings Savings Analysis: Determining and reporting the impacts

27. Information to Collect • Overall building geometry • Approximate gross square feet • Number of floors • General building shape • Type of HVAC system(s) • Approximate number of zones • Approximate number of each major type of equipment • Boilers • Chillers • Air handlers • Type of building automation system (manufacturer, model, version)

28. Collecting basic building information If you manage the building, you probably have all or most of this information at your fingertips Gather information to guide selection of trend logs to set up in the next phase Determine the overall design of the building and its mechanical systems

29. Six Primary Steps of Re-Tuning Collecting Initial Building Information: Basic building information Pre-Re-Tuning Phase: Trend-data collection and analysis Building Walk Down: Getting to know the building Re-Tuning: Identifying and correcting operations problems Post Re-Tuning: Reporting re-tuning findings Savings Analysis: Determining and reporting the impacts

30. Trend-Data Collection & Analysis: Purpose Detect potential operational problems even before visiting the building Identify problems that require time histories to detect – incorrect schedules, no use of setback during unoccupied modes, poor economizer operation

31. Steps for Trend Data Collection • Develop a monitoring plan – develop forms to guide service providers through this. Plan includes the points to trend and for each point: • Planned trend start time • Planned trend end time • Length of measurement period (2 weeks recommended) • Time interval between logged measurements (30 minutes or less recommended) • Measurement units (e.g., F for temperature) • Implement trend logs in control system

32. Analyze Trend Log Data – Major Steps Download trend log data files from BAS Format data files for compatibility with the spreadsheet analysis tool Open data files in spreadsheet analysis tool and automatically generate graphs Review graphs to identify operational issues Record operational issues for reference during re-tuning

33. Review Graphs & Identify Operation Issues Issues to investigate with trend log data PNNL spreadsheets automatically generate graphs needed We’ll look at some examples of what to look for Online reference document provides additional information and examples, which you can refer to any time you need to (see www.retuning.org)

34. ECAM Software • Five Easy, Simple Steps • Select data from existing spreadsheet • Map points (optional; required for Re-tuning) • Create schedules (optional) • Input energy project dates (optional) • Create metrics and charts ECAM≡Energy Charting And Metrics

35. Re-tuning Menu

36. ECAM: Example AHU Time Series Charts Outdoor, return, mixed, and discharge air temperatures vs. time Discharge air temperature and discharge air temperature set point vs. time Outdoor air fraction and damper position signal vs. time Outdoor and return air temperatures, damper position signal vs. time Damper, chilled water valve, and hot water valve position signals vs. time Damper position signal vs. time Discharge static pressure vs. time Supply fan speed, status, and static pressure vs. time Return fan speed and status vs. time

37. ECAM: Example AHU Scatter Charts Discharge air temperature vs. discharge air temperature set point Chilled water signal vs. hot water signal Damper signal vs. outdoor air temperature Mixed air temperature vs. outside air temperature

38. ECAM: Example Zone Charts Zone damper position signal, reheat valve position signal, occupancy mode, and Zone temperature vs. time.

39. ECAM: Example Central Plant Charts CHW supply, return, ΔT, and outdoor air temperature vs. time HW supply, return, ΔT, and outdoor air temperature vs. time CHW flow and outdoor air temperature vs. time

40. Six Primary Steps of Re-Tuning Collecting Initial Building Information: Basic building information Pre-Re-Tuning Phase: Trend-data collection and analysis Building Walk Down: Getting to know the building Re-Tuning: Identifying and correcting operations problems Post Re-Tuning: Reporting re-tuning findings Savings Analysis: Determining and reporting the impacts

41. Building Walk Down: Purpose • Get to know the building better • Develop a general impression of: • Overall building condition • Overall building design • HVAC system design • Collect some basic data on the building systems at a level of detail greater than the initial data collection

42. Building Walk Down: Major Steps Review electrical and mechanical prints Walk the outside of the building Walk the inside of the building Walk down the roof Walk down the air handlers Walk down the plant area Review the DDC system (BAS) front end

43. Six Primary Steps of Re-Tuning Collecting Initial Building Information: Basic building information Pre-Re-Tuning Phase: Trend-data collection and analysis Building Walk Down: Getting to know the building Re-Tuning: Identifying and correcting operations problems Post Re-Tuning: Reporting re-tuning findings Savings Analysis: Determining and reporting the impacts

44. Occupancy Scheduling • Shut off systems whenever possible • Night unoccupied schedules • Weekend unoccupied schedules • Daytime no or low use unoccupied schedules • Auditorium, class rooms, conference rooms • Includes lighting • Includes specialized exhaust • Do not restart too early • Use a startup schedule based on building needs • Do not use fresh air during warm-up except last 30 minutes for flushing building 44

45. Occupancy Scheduling (continued) • Shut off systems whenever possible • Refrain from starting up system for the occasional nighttime user or weekend user • Use bypass buttons • Unoccupied mode is a major cost saver • Simple to implement • Simple to track • Simple to administer • Sometimes the least paid employee is the most costly • Janitors working at night with all HVAC running, all fresh air open & lights on • Is this required?

46. Occupancy Scheduling (continued) • When running at night for warm up, cool down, or maintaining temperatures, do not ventilate (no outside air) • Run static pressure at ½ of normal set points, if it does not affect reheat controls • Check to make sure heated areas get full air in unoccupied modes • Push unoccupied mode air to where it is needed • Set VAV boxes in interior zones to unoccupied with 0 air flow • Set VAV boxes with reheat to a high air flow in unoccupied mode, so box will be 100% open during night cycling • Air gets to zones needing heat

47. Occupancy Scheduling (continued) • Building electric consumption should show significant energy drop for nights/weekends • Signifying setbacks are active on all HVAC systems • Base load versus peak loads should be at least 30% difference and as much as 50% with aggressive setbacks • Trended data for zone temps should show 5-10oF deviations from set points when setbacks are active during non-shoulder months • Winter zone temps should drop down to 60-65oF and summer zone temps should rise to 80-85oF

48. Occupancy Schedule (continued) • Trended data for discharge static pressures should show readings of 0” or at least 50% (half) of normal (occupied) static pressure readings • Trended data for main supply/return fan status should indicate “OFF” during unoccupied periods • Trended data for VAV boxes occupied status should indicate “Unoccupied” during unoccupied periods • Trended data for support systems (reheat pumps, reheat converters, reheat hot water boilers, chillers, towers, pumps, etc) should indicate they are turning off at night, if all areas of the building are also shut down

49. Occupancy Schedule (continued) • Unoccupied periods should include weekends, holidays and night hours during work week periods • If facility has sporadic use periods, this may require additional efforts to succeed at implementing setbacks • Make sure the “tail” is not “wagging the dog” – janitors, special events, extreme weather events, overrides, etc • How does your organization respond to trouble calls (occupant complaints)? How do you respond? Is the response a “band-aid” or a long-term solution? Overrides on schedules are not long-term solutions

50. Air Handler Data Analysis • Key conditions to look for while analyzing the charts: • Unoccupied or 24/7 operation • Unoccupied hour setback • Lower/higher than expected supply air temperature • Excessive outdoor air intake • During occupied periods • During pre-/pre-cooling periods • Significant reheat during summer/cooling season • Is the supply fan modulating (if VAV) • Higher than normal static pressure • Set point and static pressure resets • Economizer is not utilized or not working properly