Secondary Author(s)

Parker, Danny

Report Number




Water Heating; Buildings


As part of the effort towards zero energy buildings and high efficiency water heating systems, the Florida Solar Energy Center (FSEC) working under contract with the National Renewable Energy laboratories (NREL) has successfully completed a demonstration of a photovoltaic heat pump water heater (PV-HPWH) concept. The system integrates two 310Wp solar photovoltaics (PV) modules and grid tied micro-inverters with a commercially available 50-gallon HPWH. The project showcases innovative strategies for distributed PV thermal systems that limit grid interaction and provide increased thermal energy storage. The system utilizes a custom appliance control module (ACM) interface to vary thermostat settings (115 °F to 140 °F) depending on time of day and solar radiation levels. It is also programmable to setback the thermostat setting during nighttime standby and during morning recovery. By setting the thermostat down to 115 °F, it can disrupt compressor heating recovery normally set to 125 °F and shift the remainder of recovery to times where higher solar resources are available (i.e., after 10:30 am). Coefficient of performance thru October 2016 has averaged 5.22 utilizing only 1.15 kWh per day. The total system retail cost of $2053 fares considerably well compared to traditional solar thermal systems.

Date Published



Buildings; Water Heating



Rights Statement

In Copyright