PERFORMANCE OF REFRIGERATION HEAT PUMP SYSTEM BY USING BINARY MIXTURES OF R32/R744

摘要

The performances of the transcritical or subcritical cycle by using refrigerant mixtures of R32/R744 with mass fraction of 0/100, 5/95, 10/90, 20/80, 30/70, 40/60 and 50/50 were investigated. This experimental study attempts to verify the possibility of applying the new binary mixture in refrigeration systems and heat pumps. Performance evaluation had been carried out for a simple binary mixture R32/R744 transcritical or subcritical cycle by varying evaporator temperature. The results show that when evaporation temperature is 0℃, the discharge pressure are 5.59MPa and 4.86MPa with R32/R744 mass fraction of 40/60 and 50/50. Compared with pure R744, the discharge pressure reduces by 28.6% and 37.9% respectively. When evaporation temperature is 0 ℃, the input power of compressor is 1.0 kW and 1.28 kW with R32/R744 mass fraction of 40/60 and 50/50 respectively. Compared with pure R744, the input power of compressor reduces by 25.6% and 32.8% respectively. When evaporation temperature is -3 ℃, the COPh is 5.07 with R32/R744 mass fraction of 50/50 and reaches the maximum. Compared with pure R744, the COPh increases 20.4%. When evaporation temperature is -2 ℃, the COPc is 4.35 with R32/R744 mass fraction of 40/60 and reaches the maximum. Compared with pure R744, the COPc increases 20.8%. The water temperature of gas cooler reduces with the R32 ratio increases. When evaporation temperature is 0 ℃, the water temperature of gas cooler is 39.5 ℃, with R32/R744 mass fraction of 50/50. Compared with pure R744, the water temperature of gas cooler reduces by 7.3 ℃.