Evaluation of the RTF Standard Protocol Fan and Cooling Savings from Commercial-Sector Heat Pump Units Rooftop Unit Working Group (RTUG) August 20, 2012

Topic 1 Topic 2 Topic 3 BEGINNINGS RTUG recommendation to RTF in 2010 to add heat pumps to the RTU Protocol and Annual Energy Use and Savings Calculator 3 heat pumps were selected (Vancouver, WA) for metering for winter-summer 2011, continuing to winter , and currently into summer 2012 Change of data service provider from Powermand to Makad Energy disrupted data acquisition –1 site survived with all required data –1 site had most of the data –1 site dropped out due to gateway failure during provider transition

RESEARCH BACKGROUND Heat pump heating is different because it includes resistance backup heat + defrost cycles. Principal research questions included: 1.Do these heating differences fit in an energy signature model? 2.How widespread is poorly controlled/contradictory heating and cooling? 3.If the heating signature is accurately derived, how should heat pump monitoring be staged for summer/winter measurement?

METERED DATA Per RTF/RTU protocol: One-minute data intervals Total power Outside air temperature Supply air temperature

Topic 1 Topic 2 Topic 3 RESEARCH TASKS Assure measurement & data acquisition equipment installed & operating effectively properly Collect initial 12 months data + tracking of maintenance work done by the HVAC service techs Test the data with the standard RTF/RTU protocol including: – Identifying the applicable monitoring period – Making recommendations as necessary for changes in the standard protocol to accommodate heat pumps in cooling and heating modes – Present results to the RTUG for review and recommendations to the RTF on next steps

Topic 1 Topic 2 Topic 3 HEAT PUMP SIGNATURE

Topic 1 Topic 2 Topic 3 OVERALL SIGNATURE: WINTER/SUMMER Unit 1

Topic 1 Topic 2 Topic 3 METERED/PREDICTED ENERGY USE Energy Use - Unit 1 Normalized predicted annual41,244 kWh/yr Actual metered (5 months)10,537 kWh/yr Signature predicted (5 months)10,389 kWh/yr Reconstruction Error1.4% Long-term metered energy use was constructed from the winter and summer energy signatures

Topic 1 Topic 2 Topic 3 RTU PROTOCOL HOURLY ENERGY USE PROFILES-WINTER Unit 1

Topic 1 Topic 2 Topic 3 RTU PROTOCOL HOURLY ENERGY USE PROFILES-SUMMER Unit 1

Topic 1 Topic 2 Topic 3 HEAT PUMP ANALYSIS REQUIRES ANNUAL PERSPECTIVE Summer signature from July or August Winter Signature from December or January September, October, November have minimal useful signature data Measure installation needs to be coordinated with metering

Topic 1 Topic 2 Topic 3 OPERATIONAL ISSUES Site 1Site 2 Size, tons156 Loading, average duty cycle 40% Observed kWh/yr41,244NA - missing resistance load Est improved kWh/yr32,540NA Est savings, kWh/yr8,704NA Est savings, kWh/yr/ton580NA Recommended EEMs Control adjustment - faulty interstage differential leads to unnecessary resistance heating 24 hour fan on lightly loaded space could be set back at night first stage heating has low efficiency Control adjustment – unnecessary use of resistance heat, reduce lockout temperature Possible over active de-frost with alternating cycles of heating and cooling; Anomalous 3 day period around 12/18 with half power and almost no heat

Topic 1 Topic 2 Topic 3 RECOMMENDED NEXT STEPS 1. Update Regional RTU Research Database to included metered data from the heat pump project. 2. Notify the Vancouver facility operator of observed deficiencies in RTU operation. 3. Continuing metering/data collection for another 12 months, assuming there is continued access to the Dreamwatts system data, which is unknown at this time. 4. Adapt the RTF/RTU Standard Protocol and Calculator to produce winter signatures. In the near term, this adaptation could take the form of an adapted spreadsheet tool. The adaptation includes annualizing a normalized year estimate by dividing the year into portions associated with the winter and summer signatures.

Topic 1 Topic 2 Topic 3 RECOMMENDED NEXT STEPS Further test and substantiate the two-season signature approach on additional heat pump units = 10 units, 5 east side, 5 west side, with at least 6 months data, to provide for normalized annual energy use and savings estimates in the Calculator. 6. Expand the tested application of the heat pump signature by revisiting earlier heat pump metering data from the BPA RTU research program and coordinate with future BPA-sponsored heat pump metering and Pacific Northwest National Laboratory heat pump metering that is just underway. 7. Consider proposing a heat pump addition to the RTU standard protocol by the RTF in 2014 or sooner if additional data is available. In this project as well as others, the existence of an approved protocol has been shown to be a substantial analytical time saver.

Topic 1 Topic 2 Topic 3 EXPANDING THE RTF/RTU PROTOCOL  NBI is developing a detailed physical RTU model for cooling/ventilation through the Variable Rate RTU Test (VRTUT) project with NEEA/BPA  The physical model can provide measure savings estimates, benchmarking and zone characterization (net energy transfer out of the zone/space, effect of outside air temperature)  The RTF/RTU Protocol measurement approach and the aggregate results from the Calculator are not changed.  Linking the characteristics of the RTU signature to the physical circumstances of the RTU including schedules/controls, results in an enhanced predictive modeling capability supported by the energy signature under a range of variable zone and RTU operating conditions

Topic 1 Topic 2 Topic 3 Contact Mark Cherniack Howdy Reichmuth