Study on performance of bifunctional heat pump systems using HFC125/HC mixtures

A heat pump cycle using hydrofluorocarbon (HFC125)/hydrocarbon (HC) mixtures [ including HFC125/HC290 (M1), HFC125/HC600 (M2), HFC125/HC600a (M3) and HFC125/HC1270 (M4)], working both as water chiller and heat pump water heater, was studied based on fixed minimum heat transfer temperature difference between the refrigerant and the secondary fluid. The coefficient of performance and other parameters including volumetric heating/cooling capacity and exergy efficiency of the system were analysed over the full range of HFC125 composition and compared with that of systems using hydrochlorofluorocarbon (HCFC22) and HFC134a. The results show that, at certain HFC125 concentrations, the HFC125/HC mixtures exhibit better performance and can be used as promising alternative refrigerants to HCFC22 and HFC134a. The results may offer an energy efficient way to simultaneously provide heating and cooling in its present or future applications.