In order to choose a suitable method for ultra-low temperature refrigeration system from two-staged compression and cascade compression,the two refrigeration systems’ technical characteristics were analyzed comparatively using theoretical calculations of two-stage and cascade refrigeration system. Both theoretical displacement and theoretical coefficient of the two systems were compared in the economic aspect. Results indicated that compared to two-stage system,compression ratio and exhaust temperature of cascade system were lower and suction pressure and cooling coefficient were higher. At condensing temperature 40℃ and evaporation temperature−65℃,the energy consumption reduction of cascade system can reach to 15.13%,indicating that the performance of cascade system could be better in the ultra-low temperature condition.%为了探究双级压缩制冷系统与复叠式压缩制冷系统哪种更适合超低温制冷装置，通过对双级压缩系统和复叠式压缩制冷系统采用循环热力计算的方法，比较分析了双级压缩与复叠式压缩制冷系统的技术特性。同时从经济性的角度，对两种制冷方案的理论输气量、制冷系数、初投资、实际运行费用进行了对比分析。结果表明：在相同的工况下，复叠式系统的压缩比、排气温度和理论输气量均低于双级压缩系统，而复叠式系统的吸气压力和制冷系数高于双级压缩系统。在冷凝温度为40℃、蒸发温度为−65℃时，采用复叠压缩实际节能可达15.13%，即在超低温工况下复叠式系统更有前景。
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