To respond to new energy efficiency standards and environmentally friendly policies in hot climate regions, it is necessary to develop high-efficiency air conditioners. The environmentally friendly and favourable thermo-physical properties of R290 and the high efficiency of rotary compressors have led to the proposal of R290 rotary compressors for use in split-room air conditioners in hot climate regions. The performance of R290 rotary compressor at high temperatures requires in-depth research. In this study, an R290 rotary compressor was experimentally and numerically studied at different ambient temperatures (t_a = 35 °C, 46 °C, and 55 °C), using different oils (mineral oil (MO) and synthetic oil (SO)). The results show that the volumetric efficiency (η_v) and adiabatic efficiency (η_ad) of the R290 rotary compressor decrease by only 5% and 6%, respectively, from t_a = 35 °C to 55 °C; even at 55 °C, η_v and η_ad are 89% and 67%, respectively, while the decrements of the R32 rotary compressor both reached more than 10%. In addition, the R290 rotary compressor performance differs with different oils because of miscibility, solubility, and viscosity influences on leakage and friction losses.

R32 has been used as an alternative refrigerant of R410A in room air conditioners for its zero ODP, low GWP, and high performance. In this study, performance of R32 hermetic rotary compressor with high pressure shell was analyzed with a more comprehensive theoretical model. The simulation results showed good agreement with the experimental results. Besides, in order to improve the accuracy, in the theoretical model, the two phase leakage model was chosen in the leakage passage of radial clearance, and the gas leakage was considered in the side of sliding vane when the height of oil level is lower than the upper end face of cylinder. The analysis results show that the main factors that influence the cooling capacity are heating loss and leakage loss, and the main factors that influence the input power are discharge pressure loss, suction heating loss, clearance volume loss, bearing friction loss and sliding vane friction loss. The theoretical model would have great useful for designation and performance optimization of rotary compressor.