The unsatisfactory performance of the heat pump water heaters (air-to-water) in colder ambient temperatures is the main obstacle to the expansion of the residential market for this device. This study examines the possibility of retrofitting the gas-fired water heater with a heat pump water heater. The result of the investigation on the thermodynamic performance of a water heater system comprised of a heat pump water heater and a gas-fired water heater is presented in this paper.

Units: I-P