Thermodynamic Analysis of CO_2 Supercritical Two-Stage Compression Refrigeration Cycle

摘要

Two-stage vapor compression refrigeration cycle is accomplished with an intercooler. Statues of the refrigerant vapor leaving the intercooler will have the effect on the system performance. The thermodynamic analysis of the supercritical two-stage refrigeration cycle using CO_2 as the refrigerant is processed, with a condensing temperature of 35°C and an evaporating temperature of-5°C. When the intercooler operates at about the geometric mean of the evaporating and condensing pressures, compared to the single stage cycle, the coefficient of performance (COP) of the two-stage is improved. It reaches maximum when the temperature entering into the high pressure compressor is saturated. As the degree of the vapor leaving the intercooler increases, the COP of the two-stage system decreases.