Experimental Investigation on the Performance of Scroll Refrigeration Compressor With Suction Injection Cooling

Suction injection cooling can be usually used in scroll refrigeration compressor which works under the high speed or high pressure ratio condition, when the atmosphere is severe. In the present paper, the suction injection process is simulated with isobaric adiabatic mixing model, which has been employed by many researchers; and the performance of the scroll compressor with suction injection cooling was investigated experimentally. The test rig was established, and the scroll compressor with suction injection cooling was measured when the pressure ratio rose from 3.4 to 4.5, and the injection volume flow rate rose from 0 to 0.085 m³·h⁻¹. The results indicate that the discharge temperature decreases remarkably with the injection volume flow rate. Also, the COP (Coefficient of Performance) decrease with the injection volume flow rate. When the injection mass ratio is lower than 20%, the decrease of COP is acceptable, at different pressure ratio. At high pressure ratio, the COP could keep unchanged when the injection mass ratio is lower than 10%. Hence, the effect of suction injection cooling is better at the high pressure ratio and low injection volume flow rate. The ideal simulation results agree well with the experimental ones at low injection volume flow rate, but deviate from that at high injection volume flow rate. This is because that the gas-liquid separation happened at high injection ratio, and the isobaric adiabatic mixing model could not predict the process practically. Therefore, a new model will be developed to describe the process accurately.