Exergy and exergoenvironmental assessment and optimization of low GWP refrigerant for vapor compression heat pump system

Scientists have worked assiduously to find low GWP refrigerants for HVAC systems that specifically address the environmental problems of ozone depletion and global warming. R1234ze and R1234yf were considered as potential alternatives to conventional refrigerants such as R410A. Thermodynamic analysis of 4 kW air conditioning systems was conducted to assess system performance of R1234ze and R1234yf. Furthermore, exergy and exergo-environmental analysis were carried out for the heat pump system using selected environmentally friendly refrigerants. Finally, by using a multi-objective genetic algorithm, the optimum operating condition, including evaporation temperature, condensing temperature and mass flow refrigerant was determined. The result showed that the optimum operating condition of 20oC evaporation temperature, 42.57oC condensation temperature and 0.02 kg/s mass flow rate, led to exergy efficiency of 51.92% and an exergo-environmental value of 101.925 mPts/h. R1234ze has a comparable performance to R410A or performs even better.