A New Two-Stage Compression Refrigeration System with Primary Throttling Intermediate Complete Cooling for Defrosting

A new type of two-stage compression refrigeration system with primary throttling intermediate complete cooling is proposed in this paper. The defrost cycle of this system is still a two-stage compression cycle, and the refrigeration system can provide two evaporation temperatures at medium temperature or low temperature. Studies have shown that R410A is best suited for this system; increasing the evaporation temperature of 2 °C can increase COP by 4.3%; lowering the condensation temperature of 2 °C can increase COP by 6.4%; the COP of the system decreases with the increase of cooling capacity of the low-temperature stage but increase with the increase of the cooling capacity of the medium-temperature stage and the range of the system COP when the cooling capacity changes is obtained.