Development and performance testing of a polyvalent heat pump for hot and cold water production

This research investigates a polyvalent heat pump that simultaneously produces hot and cold water and uses natural refrigerants. The novelty of using a 48 V direct current compressor driven by solar photovoltaic (PV) energy and the staged retrofitting improvements to this heat pump are discussed. Empirical testing has indicated that using a suction line heat exchanger yields a 30% improvement in the heating Coefficient of Performance (COP). Rising ambient temperatures could positively and negatively impact its heating and cooling performance, respectively. In addition, an average COP of 3.8 was obtained after a one-hour simultaneous mode operation, with the average hot tank temperature rising from 32.7 to 58.9 degrees C and the average cold tank temperature dropping from 18 to 14.4 degrees C. Being capable of operating the polyvalent heat pump under renewable energy sources and utilizing all its generated heating and cooling energy contributes further to the electrification and decarbonization of residential buildings.