Basically energy balances during different tests are within 6% to ensure the validity of test results, as shown in Fig. 4 (ASHRAE Standard 116, 2010). Air-side capacity and COP are used for the performance evaluation (ASHRAE Standard 37, 2005). Refrigerant injection ratio a is defined as the injected refrigerant mass flow rate divided by the suction mass flow rate, as shown in Equation (6):
Where m_ inj is the injected refrigerant mass flow rate, and m_ suc is the compressor suction mass flow rate. To compare the difference between R32 and R410A, the performance of R410A was used as the baseline. The variation is defined in Equation (7):