Simulation study on performance of an air source heat pump system combined with phase change thermal storage using alternative refrigerants.

Abstract To solve the problems of conventional air source heat pump (ASHP) system in cold regions, a novel air source heat pump system combined with phase change thermal storage (ASHPPCTS) was proposed. A Mathematical model of the proposed system was established when charging refrigerants, such as R410A, R134a, R32 and R290, and the operating performance was simulated and analyzed. Besides, the influence of ambient temperature on operating performance of different refrigerants was also investigated. The simulation results showed that R32 is not recommended for the application in the ASHPPCTS system due to its extremely high supply water temperature in the initial discharging process; R134a is not high-efficient in the ASHPPCTS system because of its low total heat storage capacity and COP value; R410A shows excellent performance in almost every aspect, e.g., large total heat storage capacity, high COP value, and proper supply water temperature, which makes it suitable for the proposed system; R290 also shows great performance in the ASHPPCTS system, although its operating characteristics in the ASHPPCTS system is not as prominent as those of R410A. However, considering the low GWP value of R290, it can be regarded as the perfect alternative refrigerant used in the proposed system in cold regions to replace R410A. This research provided a reference on refrigerant replacements for the novel proposed system.