Advances in the Research of Heat Pump Water Heaters

摘要

This paper presents the progress of many recently correlative research works on the heat pump water heater (HPWH) and on solar-assisted heat pump water heaters. The advances in the research on compressor development, alternative refrigerant technology for a compressor HPWH are separately summarized. A new study on frosting/defrosting of an air source heat pump water heater (ASHPWH) is also discussed. The trends of some new technologies of HPWH are analyzed.