An Overview of Commercial Building Retuning

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Irma Pitts
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1 An Overview of Commercial Building Retuning Training SRINIVAS KATIPAMULA Big Ten and Friends Mechanical and Energy Conference, October 16, 2012 PNNL-SA-91228

2 Presentation Outline Background on Re-tuning (Existing Building Commissioning) Large Commercial Building Retuning Training Small/Medium-Sized Building Re-tuning Training Concluding Remarks 2

3 Why is Building Retro- Commission Training Important? 3

4 Retro-Commissioning Literature A number of studies have shown that retro-commissioning buildings can lead to significant energy savings between 5 and 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 retrocommissioning relate to our inability to control the building operations 4

5 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) It is generally true, only consistent, periodic commissioning will lead to persistence 5

6 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 retuning 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 retrocommissioning focused on identifying and correcting operational problems 6

7 Re-tuning can Fill the Gap Building re-tuning training is targeted at building operations staff Once the staff are trained to re-tune buildings, it will address both the cost and the persistence question Because re-tuning is implemented by leveraging information from building automation systems and primarily targets operational problems, cost of implementation is significantly lower than retrocommissioning Because re-tuning costs a fraction of retro-commissioning, it can be periodically done to ensure persistence 7

8 Energy Consumption Life Cycle of Retro-Commissioning/Retuning Typical commercial building behavior over time Periodic Re-tuning Ensures Persistence Continuous Re-tuning Maximizes Persistence Time 8

ate (www.retuning.org) Extending training outreach beyond WA St

9 U.S. Department of Energy Building Retuning Training Outreach Building re-tuning training was originally developed as part of a project funded by Washington State ( Extending training outreach beyond WA State ( with U.S. Department of Energy funding Intended for building operations staff, retrocommissioning providers and energy service providers Converted the training into an online interactive training Recently drafted re-tuning training for small/medium-sized building prescriptive approach 9

10 Overview of Large Commercial Building Re-tuning Training 10

Large Commercial Building Re-tuning Training Training consists of two parts Classroom training - 6 to 8 hours; limited to 20 to 25 people Field training - 1 to 2 days, depending on the size of the

11 Large Commercial Building Re-tuning Training Training consists of two parts Classroom training - 6 to 8 hours; limited to 20 to 25 people Field training - 1 to 2 days, depending on the size of the building; limited to 6 to 10 people Intent of the training Provide an in-depth training of the retuning 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 11

Six Primary Steps of Large Commercial Building Re-tuning Collecting Initial Building Information: Basic building information Pre-Re-tuning Phase: Trend-data collection and analysis Building Walk

12 Six Primary Steps of Large Commercial Building 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 12

Large Commercial Building Re-tuning- Common Problems Found Occupied schedules longer than they need to be Equipment running during unoccupied periods (e.g. exhaust fans) Discharge-air set points too

13 Large Commercial Building Re-tuning- Common Problems Found Occupied schedules longer than they need to be Equipment running during unoccupied periods (e.g. exhaust fans) Discharge-air set points too low Heating/cooling set points too close Static pressure too high Especially during partially occupied periods No resets of either discharge-air temperature set point or discharge-air static pressure set point Economizer problems Lack of resets on distribution loops (both hot and chilled water) 13

14 Purpose of Re-tuning Improve the building s energy efficiency through low-cost and nocost 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 that may require capital investment 14

So, why do we operate buildings as if it is a design day every day?

15 Building Operations! Most buildings are operated as if it is a peak day every day! Building occupancy changes every hour Driving conditions change every hour weather! So, why do we operate buildings as if it is a design day every day? Easy to implement It is perceived as providing more comfortable environment it is not! Building automation systems are capable of providing intelligent controls to adapt as conditions change, which leads to Energy efficient operations Fewer comfort issues to deal with! October 16,

16 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 16

17 Air handling Unit Points to Monitor & Example Monitoring Plan Air-Handling Unit Monitoring Plan Building Name: ABC Bank Building Re-Tuning Technician Name: John Doe, McDonalds Control Services Building Location: th Ave., Seattle, WA Date: April 3, 2007 Contact Information: (509) ; john.doe@mcs.com Planned Start Date/Time: 5/1/07 TBD Planned Measurement Period (hours, days or weeks) 2 weeks Planned End Date/Time: 5/15/07 TBD Measurement Interval (seconds, minutes, or hours): 30 minutes Floor: 1 Equipment Name: AHU-1 Point Name Measurement Description Planned Start Date/Time Planned End Date/Time Planed Measurement Period (hours, days, or weeks) Measurement Interval (seconds, minutes or hours) Measurement Units OAT1 Outdoor air temperature Degrees F MAT1 Mixed air temperature Degrees F RAT1 Return air temperature Degrees F DAT1 Discharge air temperature Degrees F DATSP1 Discharge air-temperature set point Degrees F PDIST1 Discharge Static Press in. w.c. MADamper1 Mixed air damper position % open Fan1 Fan status on/off Fan Speed1 Fan speed rpm CWV%1 Chilled water valve position % open HWV%1 Hot water valve position % open MODE1 Occupancy mode Occupied/ Unoccupied 17

18 Points to Monitor Guidelines If there are fewer than 6 AHUs in the building, we recommend that all AHUs be trended. If the building is less than 4-stories tall, pick at least one AHU from each floor. If the building is 20-story tall, trend all AHUs if there are few than 6. If there are more than 6 AHUs, trend one AHU on every other floor (maximum of 10 AHUs trended). Our recommendation is not to pick the AHU that is operating the best. We recommend that the AHU be picked randomly for monitoring. Following are the guidelines for trending zone VAV boxes: If there are fewer than 8 zones per floor trend all zones on the floor. For each floor, trend at least 1 zone on each of the four directions (north, south, east and west) and at least 4 zones in core. So, we will need at least 8 VAV boxes trended per floor If the building is less than 4-stories tall, trend 8 zones on every floor. If the building is 20-stories tall, trend all 8 zones on every other floor (maximum of 80 VAV boxes to trend) 18

19 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 19

20 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, etc. Identify Simultaneous Heating and Cooling Identify poor control loops Identify when support equipment (central plants, etc.) are operating when they should not be or not operating when they should be 20

21 Major Steps in Analysis Using Energy Charting and Metrics (ECAM) Tool Download trend log data files from BAS Format data files for compatibility with the ECAM spreadsheet analysis tool - urces.stm Open data files in ECAM spreadsheet analysis tool and automatically generate graphs Review graphs to identify operational issues Record operational issues for reference during re-tuning 21

22 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 22

design HVAC system design Collect some basic data on the building

23 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 23

24 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 24

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 25

26 26 Using the knowledge learned from trend-data analysis and building walk down to start the building re-tuning process

27 Occupancy Scheduling Purpose Determine whether night, weekend and holiday set back is being used End-use loads are following occupancy schedules Approach For each major end use, review plots of consumption vs. time or temperature vs. time or status vs. time or static pressure vs. time 27

Occupancy Scheduling (continued) Shut off systems whenever possible Night unoccupied schedules Weekend unoccupied schedules Holiday unoccupied schedules Daytime no or low use unoccupied schedules

28 Occupancy Scheduling (continued) Shut off systems whenever possible Night unoccupied schedules Weekend unoccupied schedules Holiday unoccupied schedules Daytime no or low use unoccupied schedules Auditorium, classrooms, 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 28 28

29 Occupancy Scheduling (continued) Building electric consumption should show significant energy drop for nights/weekends Signifying set backs are active on all HVAC systems Base load versus peak loads should be at least 50% difference and as much as 80% with aggressive set backs Trended data for zone temperatures should show between 5 o F and 10 o F deviations from set points when set backs are active during non-shoulder months Winter zone temperatures should drop down to between 60 o F and 65 o F and summer zone temperatures should rise to between 80 o F and 85 o F 29

30 Occupancy Scheduling (continued) Enable unoccupied mode and night setback control Shut off units at night and weekend and holiday Turn off heating systems (for reheat only) during summer When reheat system is shut off, room comfort may be maintained by increasing supply air temperature for constant volume units Do not turn heating off too early in the summer to avoid having to turn the system on and off repeatedly Turn off systems during unoccupied hours Slow down systems during unoccupied/lightly-occupied hours 30

31 Examples of Occupancy Scheduling: Bad and Better 31

32 Examples of Occupancy Scheduling: Good 32

33 Examples of Occupancy Scheduling: Good 33

34 Test Your Knowledge

Air-Handling Fan Scheduling Damper and Cooling Coil Commands indicate weekend operation Damper and Cooling Coil Valve start action at 7:30 AM and end at 10 PM on Saturday,

35 Air-Handling Fan Scheduling Damper and Cooling Coil Commands indicate weekend operation Damper and Cooling Coil Valve start action at 7:30 AM and end at 10 PM on Saturday, 11:30 PM on Sunday (15-16 Hours occupy) This air-handling system serves an auditorium What would be your recommendation for a low cost/no cost control operation change? 35

36 Air-Handling Fan Scheduling Discussion Points: Is the schedule for this air-handling system appropriate? For an education institution, is this space likely occupied every weekend? What would be your recommendation for a low cost/no cost control operation change? Correct answer: Reduce or eliminate schedule or provide method to activate occupancy for a 2-4 hour maximum time or both 36

37 Air-Handler Data Analysis: Static Pressure Purpose: Determine whether the static pressure set point is too high or too low Approach: For each air handler, review a plot of the damper positions of all VAV units vs. time Look for situations where: Most dampers are nearly closed during cooling static pressure too high Several VAV boxes on an air handler have dampers fully open static pressure is too low and VAV boxes are not able to meet zone loads starved boxes Dampers are not modulating as conditions change VAV boxes that are not being controlled or not responding to control signals 37

38 Static Pressure Operations: Constant Static Pressure 38

39 Static Pressure Operations: Constant Static Pressure 39

40 Static Pressure Operations: Zone VAV Damper Position vs. Time 40

41 Static Pressure Operations: VAV Damper Position vs. Time 41

42 Static Pressure Operations: VAV Damper Position vs. Time 42

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

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 43

44 Highlights of Re-tuning Every set point adjustment made will have an impact of some sort on the utility meter Can save energy and keep occupants comfortable It takes time to tune a building There are no magic set points that work all the time Always monitor the utility meters (gas & electric) to see what affect you have had Look at the big picture when making adjustments Watch the meter profiles weekly Learn and know the building s personality 44

Large Commercial Building Re-tuning e- Learning Adds more reach to instructor-led classroom and field training Available for free Provides learners: A step-by-step walk through of the building

45 Large Commercial Building Re-tuning e- Learning Adds more reach to instructor-led classroom and field training Available for free Provides learners: A step-by-step walk through of the building re-tuning process Opportunity to practice meaningful re-tuning activities in real-world contexts and situations A variety of downloadable resources (checklists, templates, example plans, etc.) to use on the job 45

virtual building walk down Interact with building occupants Work through a variety

46 Large Commercial Building Re-tuning: Learn by Doing Work within a virtual, 3D commercial building Collect and analyze building prints and trend data Perform a virtual building walk down Interact with building occupants Work through a variety of interactive scenarios designed to target specific re-tuning issues throughout the building 46

47 Large Commercial Building Re-tuning Training Resources 10 re-tuning guides, each addressing an area of re-tuning Short course or training module How to use ECAM and interpret graphs generated by ECAM Working on another short course How to setup trends in a building automation system 47

48 Overview of Small/Medium-Sized Commercial Building Re-tuning Training 48

Small/Medium-Sized Building Re-tuning Training: Introduction The purpose of this training is to train students/technicians on how to make small/medium-sized buildings more efficient leading to energy

49 Small/Medium-Sized Building Re-tuning Training: Introduction The purpose of this training is to train students/technicians on how to make small/medium-sized buildings more efficient leading to energy savings and reduced operating cost The knowledge and skills learned through the training will be highly valued by organizations and companies seeking to improve the performance of small/medium-sized buildings It will also prepare the participating students/technicians for hands-on field training It will also provide an opportunity for students/technicians to ask questions and get clarification on any aspect of the re-tuning process 49

Small/Medium-Sized Commercial Building: Scope Small-sized Buildings: Defined as 5,000 sf or less No building automation system Medium-sized Buildings: Defined as greater than 5,000 and up to 50,000

50 Small/Medium-Sized Commercial Building: Scope Small-sized Buildings: Defined as 5,000 sf or less No building automation system Medium-sized Buildings: Defined as greater than 5,000 and up to 50,000 sf No building automation system Focus is on low-cost and no-cost ideas and methods for saving energy A prescriptive approach to identify and correct building operational problems that lead to energy waste May include identifying other opportunities for improving energy efficiency that require investment 50

51 Small-Sized Commercial Building Characteristics Buildings less than 5,000 sf Percent of total number of commercial buildings 54% Percent of total commercial building square footage 22% Percent of total commercial building energy use 21% Even a 10% reduction in HVAC and lighting energy consumption will lead to 6 kbtu/sf/year or 60 mbtu/yr for a small commercial building of 10,000 sf Refrigeration, 11.72, 14% Consumption Breakdown in kbtu/sf/year and % of Total Computer Use, 1.77, 2% Office Equipment, 1.1, 1% Cooking, 5.59, 7% Water Heating, 6.08, 7% Miscellaneous, 6.2, 7% Lighting, 15.32, 18% Heating, 27.7, 32% Cooling, 6.51, 8% Ventilation, 3.53, 4% 51

52 Medium-Sized Commercial Building Characteristics Buildings greater than 5,000 sf and up to 50,000 sf Percent of total number of commercial buildings 3% Percent of total commercial building square footage 6% Percent of total commercial building energy use 5% Even a 10% reduction in HVAC and lighting energy consumption will lead to 5.5 kbtu/sf/year or 165 mbtu/yr for a medium-sized commercial building that is 30,000 sf in size Consumption Breakdown in kbtu/sf/year and % of Total Computer Use, 1.92, 3% Office Equipment, 0.64, 1% Refrigeration, 5.54, 8% Cooking, 1.45, 2% Lighting, 16.6, 23% Water Heating, 6.82, 9% Miscellaneous, 7.45, 10% Heating, 19.09, 26% Ventilation, 4.8, 7% Cooling, 8.1, 11% 52

Small/Medium-Sized Building Re-tuning Training: Major Focus Areas Building Envelope Heating, Ventilation and Air Conditioning Systems and Controls Packaged air conditioners and heat

53 Small/Medium-Sized Building Re-tuning Training: Major Focus Areas Building Envelope Heating, Ventilation and Air Conditioning Systems and Controls Packaged air conditioners and heat pumps Gas furnaces Air distribution system Lighting and Lighting Controls Domestic Hot Water/Process Hot Water Office Equipment/Process Equipment Internal Conditions Meter Profile 53

54 Small/Medium-Sized Building Re-tuning: Definition and Scope Building re-tuning is a systematic process to identify and correct operational problems that lead to energy waste Although the original building re-tuning process developed for large commercial buildings leveraged data from building automation system to identify operational problems, the process for small/medium-sized buildings will be prescriptive and will not rely on detailed monitored data Because small/medium-sized buildings will mostly have packaged units for heating and cooling with simple air distribution, and are controlled by a zone thermostat, many of the recommendations for efficiency improvements will be prescriptive Some of the topics covered in this building re-tuning training are often covered in training associated with energy auditing and retrocommissioning for small/medium-sized commercial buildings 54

55 Small/Medium-Sized Building Re-tuning Training: Approach Because most small/medium-sized commercial buildings will not have a building automation system, the training will be prescriptive It will use a four step approach Initial data collection phase: Collection of information about the building Investigation phase: Building walk down to identify and characterize the building operations Implementation phase: Application of prescriptive re-tuning measures Documentation phase: Reporting of measures implemented and calculation of energy saving 55

Targeted Building Types There is a lot of diversity in small/medium-sized commercial buildings However, some building types are somewhat homogenous office, education, retail (strip mall, enclosed

56 Targeted Building Types There is a lot of diversity in small/medium-sized commercial buildings However, some building types are somewhat homogenous office, education, retail (strip mall, enclosed mall, retail other than mall), outpatient health care, religious worship and service (other than food or retail) They make up about 62% of all small/mediumsized commercial buildings (<50,000 sf) The remainder of the building types include food sales, food services, and refrigerated and non-refrigerated warehouses These are different from the first group So, re-tuning training will be focused on the first group of building types 56

providers or control vendors) hired to improve a building s energy efficiency, People interested in

57 Small/Medium-Sized Building Re-tuning Training: Intended Audience Onsite employees (custodial staff) responsible for day-to-day building operations, Offsite contractors (retro-commissioning agents, service providers or control vendors) hired to improve a building s energy efficiency, People interested in entering this field, including college students and military veterans, and People currently involved in weatherization work 57

58 Lessons Learned from Large Commercial Building Re-tuning Training 58

59 Issues for Successful Application of Large Commercial Building Re-tuning Important to make adjustments during the re-tuning process. Do not defer implementation until later Building operations staff need to know that they have the authority to implement minor operational changes without risk of reprisal Building operations staff need to have confidence in the process. To develop confidence, operators can make small incremental changes over time and observe the responses of occupants When re-tuning measures are implemented, the energy consumption information should be reviewed so feedback can be provided to building managers on the success 59

through implementation of no-cost and low-cost measures But, the human factor is a real issue in realizing

60 Key Lessons Learned Many commercial buildings have array of operational problems Trained building operations staff can re-tune buildings, if empowered Building re-tuning can yield energy savings between 5% and 20% through implementation of no-cost and low-cost measures But, the human factor is a real issue in realizing re-tuning benefits in practice In the long run, automation is key to persistence of optimal building operation 60

Online Re-tuning Resources All classroom re-tuning training material, including train-the-trainer instructors manual Energy Charting and Metric tool, a

61 Online Re-tuning Resources All classroom re-tuning training material, including train-the-trainer instructors manual Energy Charting and Metric tool, a semi-automated Microsoft Excel -based trend data analysis tool, including user guides and sample data Guides to re-tuning measures Community College Education Curriculum 61

62 Questions?

HVAC Controls Upgrade FPT: Scheduling, Override & Night Setback; End to End ( )

HVAC Controls Upgrade FPT: Scheduling, Override & Night Setback; End to End ( ) REQUIRED SEQUENCES CONTROLS/FEATURES: Indicate that the specific feature is installed and record the date it was verified to work correctly. Indicate NA if not required by grant. Installed? Date Tested