Center for Energy and Environment Use of Building Automation Systems for (Retro)Commissioning Neal Ray, Center for Energy and Environment Gustav Brändström, Center for Energy and Environment January 17, 2012
Agenda Introduction Trending Setup Collecting and Processing Trend Data Using Trends in (Retro)Commissioning Wrap Up Page 2
Introduction Trending and Trend Data Trending overview Building Automation Systems (BAS) or data loggers Data is exported from the BAS or loggers for spreadsheet analysis Raw Data has to be formatted to be analyzed. Page 3
Introduction Trending and Trend Data Trend Data Time series data exported from BAS or data loggers 15 minute interval 6 continuous months minimum Weather-dependency Modes of operation Typical AHU has 15 channels Typical buildings have 300-500 channels 5-8 million data points Page 4
Trending and Trend Data Mechanical Equipment Summary Table 1 Building Automation System 2 Buildings 184,710 Interior Square Feet 9 Air Handlers 186 VAV Boxes 10 Exhaust Fans 1 Electric Unit Heaters 4 Chillers 4 Dry Coolers / Cooling Towers 5 Modular Cooling Units 3 Hot Water Boilers 15 Pumps (HW, CHW, etc) 2 Humidifiers 4 Fan Coil Units 2,490 Point available on the BAS 993 Minimum Points for Trending 0 Loggers required Page 5
Introduction Trending and Trend Data Why So Much Trending? Trend data allows you to identify operational issues you wouldn t find otherwise. Unoccupied operation Leaky valves, stuck dampers, etc Suboptimal controls sequences Trend data allows you to more accurately calculate savings Once it is setup it keeps running You can never tell the weather what to do Page 6
Trending Setup Trending Basics Point Addresses Storage Buffer storage Historical storage How points on the automation system are defined Binary Analog Page 7
Trending Setup Trending Setup Go to the building automation system and set up trends Problems encountered Learning all the different building automation systems Tedious work on occasions, instances where 3,000 to 4,000 points need to be trended Assuring system can handle the trend information stored on it Assuring the trend data is collecting How to extract the trend data in a useable format once it is setup and collecting Have to decide if it is cheaper to trend yourself or hire control contractor to do so during the project. Remote Access Page 8
Trending Setup Trending Setup Learning the automation system Many different types of systems Have to contact control contractor Might have to hire contractor to help you (typically 4 hours or work) Find User Manual for system Usually located on the hard drive Have to learn how to extract data as well. The more systems you work on and more familiar with automation systems you become the easier this task becomes. Page 9
Trending Setup Trending Setup First check to make sure the system can handle all the trend data you want to setup and collect Check with control contractor May have to go beyond control technician at site Someone at the company will know how to trend on the system and the capabilities. Even if control contractor tells you it can be sure to do test run first before setting all trends up. Setup about 25-50% and let the trends collect Check up on the system after one week Page 10
Trending Setup Trending Setup Remote Access Work with site IT and control company to see if Remote Access is possible Web based Remote Desktop Special software If remote access can be granted a lot of trending work can be done at the office and not the site. Will save time and project budget. Page 11
Trending Setup Trending Setup Actual Trend setup Tedious Work Will take anywhere from 8 to 20 hours to set up trends Possible have to trend 3,000 to 4,000 points May have to repeat the same procedure over and over again for each point. Why so many trends Page 12
Trending Setup Trending Setup Assure trend data is collecting Initial trend setup should be checked one week after setup. Once all trends are setup should be checked again after one week. Team Work Control contractor and site IT need to be aware of what you are doing. If not data may be lost. Page 13
Collecting and Processing Trend Data Collecting and Processing Trend Data Extracting Trend Data Each system is vastly different Different types of files for different types of systems Text, CSV, Database, SQL Database, Excel etc. One large file or one file per trend point Work with Control Contractor They can show you where trend files reside on system Remote Access is a big help in this area Should extract data once every two weeks, to once a month. Page 14
Collecting and Processing Trend Data Collecting and Processing Trend Data Different Ways it can be done Software available Could design own software Use Excel and VBA code Once code is written have it for future projects Example Page 15
Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Use of trending in Commissioning Verify sequences of operation Find problems with valves, dampers, VFD operation, etc. Use of trending in Retrocommissioning Understand sequences of operation Find problems with valves, dampers, VFD operation, etc. Find correlations of energy use Page 16
Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Verify Economizer Operation Plot %OA and OAD vs Outside Air Temperature (OAT) Filter for Fan ON Should clearly see Economizer Lockout and minoa% Exponential curve, peak at 100% at DAT stpt, stay at 100% until lockout. Page 17
Page 18 Locked OAD at 0%
Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Verify Economizer Operation Plot (RAT-MAT) vs (RAT-OAT) (RAT-MAT)/(RAT-OAT) = %OA (Mixed Air Method) Can see all modes of economizer operation Points under the ideal line is over-ventilating and vice versa + Ideal line from setpoints Page 19
minoa% 100% Econ Modulating Econ Page 20
Page 21 Locked OAD at 0%
Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Verify Boiler Operation Plot HWS-T, HWS-stpt, HWR-T, and HW dt vs OAT Filter for HW Pumps ON Can see HW reset if present Can see hot water dt performance Page 22
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Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Verify Chiller Operation Plot CHWS-T, CHWS-stpt, CHWR-T, and CHW dt vs OAT Filter for Chiller ON Can see CHW reset if present Can see chilled water dt performance Page 24
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Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Find leaking valves Plot DAT-MAT vs Valve Position Filter for Pumps ON, AHU ON Can see if there is a temperature rise/fall across closed coil Can also see if valve is reversed (N/O) Page 26
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Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Helpful formulas for trend processing %OA = (RAT-MAT)/(RAT-OAT) MOD() To get Time of Day =MOD([Cell with date and time],1) 1/17/2012 4:35 PM -> 4:35 PM AVERAGEIFS() To average numbers in a range given certain criteria COUNTIFS() To count numbers in a range given certain criteria MID() Extracts text (or numbers) from within a text Page 28
Using Trends in (Retro)Commissioning Using Trends in (Retro)Commissioning Helpful Excel Tips Put Date/Time and OAT columns to the far left Excel assumes the left most column selected is the X-axis when creating graphs Setup spreadsheet columns in the same order for similar equipment for ease of plotting Select range and Paste into existing graph for added Series Page 29
Wrap Up Wrap up Trending setup is tedious, but Easier with practice More trending = less functional testing (more in office = less travel) Certain things can only be found by trending Once it is going, it will keep going Page 30
Wrap Up Wrap up All systems are different Setup Extraction Processing But once you know it, you know it Trending techniques Page 31
Page 32 Questions?