A comparative study on the thermal performance of R290 and R32 rotary compressors in the air conditioner

R290 has been considered as an ideal refrigerant in the air conditioning system owing to its environmentally friendly properties. In this paper, a mathematical model considering the leakage process, heat transfer process and discharge process has been applied to investigate the working process of R290 and R32 compressors. The p-V diagram and T-V diagram of R290 compressor have been compared with those of R32 compressor. The thermal performance parameters have been calculated and the simulation results show that compared with R32 compressor, R290 compressor has a similar COP, a lower discharge temperature but a lower cooling capacity. If the stroke volume is the same, the cooling capacity of R290 compressor is only half that of R32 compressor. Besides, R290 compressor has lower pressure and temperature rise curves, which fluctuate at the end of discharge process due to the inappropriate discharge valve. In addition, the leakage characteristics of R290 and R32 compressor are similar due to the determined geometric parameters of compressor but the volumetric efficiency of R290 compressor is relatively low. A smaller clearance and a thinner discharge valve plate are suggested for an R290 compressor.