Two-Stage Refrigeration System for Air-Conditioningat Extremely High Ambient Temperatures
Gu Zhaolin¹，Zheng Donghong¹,Li Yun¹,Xu Dongping²
(1.School of Environmental and Chemical Engineering,Xi'an Jiaotong University,Xi'an 710049, China;2.Yongsheng Corporation, Jiangsu)

Abstract：A two-stage refrigeration system for air-conditioning is studied to solve such problems as higher pressure ratio, higher heat capacity of heat exchangers, and lower coefficient of performance, which occur when a single-stage refrigeration system operates at extremely high ambient temperatures. Some measures, such as controlling the dryness fraction of the refrigerant in the evaporator, liquid subcooling and superheating, are taken to improve the performance by thermodynamic simulation of the two-perature of high-stage compressor is reduced by 10 degrees C for the case of the suction gas with some superheating and by 20 degrees C for the case of the suction gas without superheating, and the coefficient of performance of the system is increased by about 15%.
Keywords：coefficient of performance (COP);two-stage compression;refrigeration cycle