Abstract:  In order to investigate the operating performance of the ocean fishing vessel refrigeration system, this paper establishes a mathematical model and experimental verification for the marine R404A stand-alone two-stage compression refrigeration system and the R404A/R23 cascade refrigeration system, and compares the impact of system evaporation temperature and intermediate temperature on the two-stage cyclic and cascade cyclic high-temperature compression ratios, high and low pressure refrigerant flow, refrigeration coefficient and thermodynamical perfectness, etc. The results show that as the intermediate temperature rises from -22°C to -7°C, compared with the two-stage cyclic, the cascade cyclic high-temperature compression ratio decreases faster, the high and low pressure refrigerant flow changes more smoothly, and under different working conditions, there are optimal intermediate temperatures to maximize the system refrigeration coefficient. When the condensing temperature is 40°C and the evaporation temperatures are -65°C, -60°C and -55°C, the cascade system refrigeration coefficient is higher than that of the two-stage system by 21.33%, 22.25% and 22.18% respectively. Under the operating conditions of -55℃~-65℃, the performance of the cascade system is obviously better than that of the two-stage system.

Key words: cascade system, two-stage compression system, evaporation temperature, intermediate temperature, marine refrigeration

摘要： 为探究远洋渔船制冷系统的运行性能，分别对船用R404A单机双级压缩制冷系统与R404A/R23复叠式制冷系统建立数学模型与试验验证，对比研究系统蒸发温度与中间温度对双级循环与复叠式循环高温级压缩比、高低压级制冷剂流量、制冷系数及热力完善度等性能参数的影响情况。结果显示：随着中间温度从-22℃上升至-7℃，相比双级循环，复叠式循环高温压缩比下降更快，高低压制冷剂流量变化更加平稳，且在不同工况下，分别存在最佳中间温度使系统制冷系数最大。当冷凝温度为40℃，蒸发温度分别为-65℃、-60℃、-55℃时，复叠式系统制冷系数分别高于双级系统21.33％、22.25％、22.18％。在-55℃～-65℃运行工况下，复叠式系统性能明显优于双级系统。

关键词: 复叠式系统, 双级压缩系统, 蒸发温度, 中间温度, 船用制冷