Working performance of R-32 two-stage compression system in domestic air-conditioner

A numerical simulation model of a two-stage compression refrigeration system with vapor injection using R-32 as refrigeration is newly presented in this paper. The middle chamber state of the twin rotary compressor with vapor injection was simulated. Based on that, the whole system model was set up and it was validated by comparing the predictions with measured data. The results show that, compared with No-injection cycle, R-32 vapor injection system provides very significant performance improvements for cooling performance. The most suitable volume ratio of the high-pressure cylinder to low-pressure is between 0.65 and 0.78; Compared with the single-stage compression system, the cooling capacity and COP of the two-stage compression system can improve 5-15% and 10-12%, respectively; The optimum vapor injection pressure corresponding to the comprehensive cooling performance was 1.3-1.8 MPa.