Modeling and performance evaluation of heat pump water heater systems

Countries around the world have introduced strict energy policies to mitigate the adverse effects of global warming and climate change. These policies call for a change on a massive scale to decarbonize existing energy systems and to provide energy flexibility. Building stock accounts for a large percentage of carbon emissions. To support the decarbonization of buildings, this paper investigates the performance of a heat pump water heater (HPWH) system under a hot water draw-off load profile. The HPWH system was modeled in TRNSYS using a water-to-water heat pump, a hot water storage tank, and hydraulic components. A simulated load profile tapped a net useful energy content of 11.655 kWh in terms of domestic hot water. The coefficient of performance of the heat pump was calculated. In addition, the temperature distribution inside the storage tank and the water heating efficiency were obtained. The performance estimation of HPWH systems under daily heat load schedules may help in the design and selection of an energy efficient system which would, in turn, contribute to the decarbonization of building stock