Commercial Heat Pump Water Heater Research for Schools

Advanced Energy evaluated the performance of an A.O. Smith commercial electric air-source heat pump water heater at Rand Road Elementary School in Garner, North Carolina. The heat pump water heating system was installed in early July 2012 and had operational problems for several months. The system became fully operational in late November 2012 and has run reliably since.

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Advanced Energy monitored the system over a five-month period from January 24, 2013, to June 12, 2013. The team then performed supplemental testing in August 2013 to resolve questions that came up when analyzing the initial monitoring data. Results showed that while the heat pump increased water heating system efficiency, it also increased standby losses due to the additional less-insulated heat pump water storage tank.

A field test conducted during the supplemental testing found that the water heater’s measured coefficient of performance (COP) closely aligned with the manufacturer’s specified value. The test revealed a COP of 3.48, and the expected COP based on the manufacturer’s performance tables and actual operating conditions during the test was 3.88.

Based on the measured results, Advanced Energy estimates a 12 percent annual energy reduction associated with the heat pump water heater at Rand Road Elementary.