Abstract
The purpose of this study is to investigate the performance of an autocascade refrigeration system using the refrigerant mixtures of R-134a(64${\sim}$72wt%), R-23(20${\sim}$25wt%) and R-14(8${\sim}$12wt%) as working fluids by experiment. The experimental apparatus consisted of a autocascade system with a compressor, condenser, evaporator, gas-liquid separator and cascade condenser, etc. Two main causes to this failure were considered as follows. First, the pressure ratio in the compressor was extremely increased at the beginning of the experiment. Second, the outlet temperature in compressor was higher than its limited temperature. For a stable operation of the compressor, a portion of the mixed refrigerant was by-passed at the inlet of the heat exchanger and transferred directly to the suction of the compressor in the modified system. The experimental parameters were changed weight of R-134a(1800g, 2800g), R-23(700, 800, 900g) and R-14(300, 400, 500g). The results showed that the best performance in case of R-134a of 2800g, R-23 of 900g and R-14 of 500g.
