Figure 15 and Figure 16 summarize the comparison of low-stage and high-stage isentropic and volumetric efficiencies of R410A and R32 in a two-stage cycle with vapor injection at extreme conditions. It can be seen that at the ambient temperature of 46ºC and -18ºC, the isentropic efficiencies are almost the same but the volumetric efficiencies of R32 were significantly lower than those of R410A. This explains the significant refrigerant mass flow rate decrease in these conditions, as shown in Figure 11.