极高环境温度下的两级空调系统研究

Two-Stage Refrigeration System for Air-Conditioning at Extremely High Ambient Temperatures

针对极高环境温度下单级空调制冷系统运行中存在着的诸如压缩机的压缩比大、换热器热负荷大、性能系数小以及经济性差等问题 ,采用一级节流中间不完全冷却和一级节流中间完全冷却的两级制冷系统对单级制冷系统进行改进 ,使压缩机排气温度降低了 10℃ (一级节流中间不完全冷却 )或 2 0℃ (一级节流中间完全冷却 ) ,符合排气温度的要求 ,同时性能系数提高了 15 % ,因而使压缩机功耗降低 ,达到了提高单位工质的制冷量并使性能系数最优的目标 .

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 stage refrigeration system. Compared to the single stage refrigeration system the discharge temperature 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%.