Thermo dynamic analysis of transcritical CO2 two-stage compression booster system

In this paper,a thermo dynamic model of transcritical CO2 two-stage compression booster system was established. The factors affecting the system performance such as outlet temperature of gas cooler,pressure in expansion tank and degree of supercooling were numerically analyzed. The results show: the optimum discharge pressure of the system increase rapidly with the gas cooler exit temperature increases,and when the outlet temperature of the air cooler is constant,the optimum discharge pressure slightly increases with the evaporation temperature decrease. At the same time,the optimum COP of the system decreases rapidly with the increase of air cooler outlet temperature. The optimum dryness value of system increases with the air cooler outlet temperature rises. When the evaporation temperature is constant,the COP of the system decreases with the increase of the pressure in the expansion tank,and the system COP gradually increases with the increase of the undercooling degree,but more than the influence of evaporation temperature on the system performance smaller.