Reducing energy use for heating hot water remains a major challenge around the world. This paper describes a novel solar photovoltaic assisted heat pump water heater (PV-HPWH) which achieved an 83% reduction (COP 5.4) in water heating energy compared with electric resistance. This technology demonstrates very large potential energy savings around the U.S.
The system uses two 300 Watt PV modules, micro-inverters and innovative controls to produce and store daily hot water. The system promises to cost less than half that of solar thermal systems, with greater reliability, no freeze protection and potentially superior performance in cloudy locations. Moreover, no net metering is needed for the PV which with two modules would make for a simple installation.
Notable quote: "Marrying PV with heat pump water heating and smart controls may be a key technology for eliminating gas boilers and water heaters around the world.”
Title: “Potential of a Very High Efficiency PV Assisted Heat Pump Water Heater,” by Danny Parker, Florida Solar Energy Center