BPA RTU Winter Operation Presented to: RTUG August 2010 Presented by: Kathryn Hile, The Cadmus Group Howard Reichmuth, New Buildings Institute

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Winter Analysis Overview  Improvements to analysis template  Downloading and organizing data  Fan operation – schedules  Gas pack operation  Heat pump operation  Winter economizing (or cooling)  Additional opportunities  Lessons learned 2

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Winter Sample  45 serviced RTUs –32 at 3 sites in Puget Sound area –13 at 3 sites in Tri-Cities area  4 baseline RTUs in Tri-Cities: serviced spring RTU TypeNumber of Units SubtractionsUnits Analyzed All Electric1 1 Gas Pack Heat Pump10 0

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Analysis Template Improvements  All winter data in one spreadsheet (at hour level)  Much smaller analysis files  Automation with SAS and VBA  Time series dynamic graph  Both SA min and SA max plotted in time series 4

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N 5 Downloading and Cleaning Data HOBOlink Excel Visual Basic SAS

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Data Preparation Process  Download zip file from HOBOlink with data from all HOBOs  Organize by HOBO  Create one file for each HOBO, based on power, one sheet for each two-week period  Import to SAS with keys for CT size, WattNode scale factor, fan low and fan high 6

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Data Preparation  Calculate hourly and daily minimums, maximums, totals and averages  Export to Excel  Only full 24 hour days used to create energy signature  View data in hourly compressor map, dynamic time series and energy signature 7

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Data Collection Issues  Some (not many) sensors failed last winter, and four sites required troubleshooting to fix –Splitters –AC adapter – battery failure  Downloaded data –One site: two units had nonsensical data –One site: three sensors just disappeared from HOBOlink – result of the AT&T upgrades last fall? 8

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Calculating Percent Outside Air 9

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Winter Operation  Schedules – fan ON or AUTO  Fan kW, duty, base load  Typical signatures 10

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Fan Mode = ON  Winter numbers similar to pilot data 11 Winter DataSummer Pilot Post-Servicing Data RTU Fan kWFan DutyBase LoadFan kWFan DutyBase Load RTU % % HP % % HP % % GP % % GP % % AC % % AC % % RTU % % RTU % % RTU % % 14.43

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Fan Mode = AUTO  Small sample  Fan kW very close; fan duty and base load differed 12 Winter DataSummer Pilot Post-Servicing Data RTU Fan kWFan DutyBase LoadFan kWFan DutyBase Load RTU % % RTU % % HP % % GP % % GP % % 4.07 AC % % 29.31

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Signatures  24 of 32 energy signatures were as expected  8 needed more investigation to understand performance 13

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Typical Signature 1 14  Operates same set schedule each day

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Compressor Map  Same RTU as previous slide 15

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Time Series 16

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Typical Signature 2 17  Operates slightly longer at lower temperatures

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Compressor Map  Same RTU, compressor map 18

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Typical Signature 3 19  Two signatures – Monday – Saturday, and Sunday  Unit may have reached setback temperatures when average daily temperatures below 40

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Gas Pack Findings  Fan power calculated this winter was close to metered pilot data in almost all cases  Fan duty was close to metered pilot data in units with fan scheduled ON  Fan duty and base load were difficult to predict from summer metered data when fan ran in AUTO mode 20

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Winter Heat Pump Operation  Heat pumps were trickier  Smaller sample, all at a notorious site  Units served either offices or fabrication (manufacturing) spaces  Four units did not have economizers 21

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Heat Pump Typical Operation  Energy increases as temperatures decrease  Steeper slope than for cooling 22

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Heat Pump Compressor Map  Same unit as previous slide 23

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Heat Pump Time Series 24

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Heat Pump Findings  Typical heat pumps will have a second sloped line  Need summer data (spring was not warm enough) to connect winter and summer usage  Will use that to calculate and predict total annual energy use, not just cooling and fan 25

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Winter Economizing  Some units modulate dampers to take advantage of free cooling.  SA min and SA max track OAT  Three speed fan? 26

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Heating to Economizing  Fan operates at different power when heating or economizing 27

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Atypical Performance  Balance point below the range of monitored temperatures  Cooling at low temperatures  Units serving the same space  Two units with bad data 28

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Low Balance Point 29

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Cooling at Low Temperatures  Mechanical cooling at 25 degrees 30

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Cooling at Low Temperatures 31

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Heating a.m., Cooling p.m.  Two different max kW, at 3.5 kW, cooling (SA min at 55) and heating 4.5 kW (SA max at 90) 32

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Someone’s Been in my RTU… 33

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N …Twice! 34

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Economizer Findings  Cooling at temperatures below 40 degrees. Why? Controls? Or dampers didn’t modulate because broken? Bad sensor? Comments? Significant savings opportunity?  Cooling in the degree F. Could economizer changeover temperature be increased for additional savings?  Winter is a good (better than summer?) candidate for economizer savings 35

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Preliminary Annual Signature  Winter: –Standard, flat gas pack –Standard, sloped – but could we just take an average and keep slope at 0? –Gas pack with two occupancy schedules –Heat pump – is this signature messier than it would be during summer cooling? TBD.  Atypical. 36

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Ex: AC w/Elect Resistance Heating 37

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N AC Compressor Map 38

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N AC Time Series 39

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Next Steps in Research  Draft annualized savings methodology with separate characterizations of annual operation for summer and winter  Data block interval analysis  Recommendations regarding fan schedule persistence  Additional persistence analysis  Measure life implications from the data  Updated M&V protocol recommendations 40

B O N N E V I L L E P O W E R A D M I N I S T R A T I O N Web-Enabled Thermostats  Test the web-enabled thermostat as an M&V tool as a substitute for data-loggers –Data-friendliness? –How complete is it? –What does it look like?  Use the current analysis protocol and modify it for these data 41