根据《蒙特利尔议定书》，渔船制冷系统所用R22制冷剂因对大气臭氧层具有破坏作用，应在2030年前被禁止使用。因此寻找理想的替代制冷剂迫在眉睫，混合制冷剂通过组分筛选与配比，既可以满足系统制冷需求，又达到环保要求，成为替代传统制冷剂的主流趋势。本研究设计了单机单级的自复叠制冷系统，采用化工流程模拟软件开展了多元混合制冷剂的应用替代研究。基于自复叠制冷系统特点和混合制冷剂热物性，面向-65 ℃的目标温区，筛选了R14、R23、R134a和R245fa四种制冷剂，分别组成二元、三元和四元混合制冷剂。针对自复叠式制冷系统，开展了二元、三元和四元混合制冷剂在不同组分不同浓度下的热力计算分析。结果显示：采用四元混合制冷剂的制冷系统相比于采用二元、三元混合制冷剂的系统制冷系数更优。当四元制冷剂组元配比为R14/R23/R134a/R245fa（0.35/0.36/0.1/0.19）时，制冷系统的COP可达1.037，排气压力与吸气压力分别为1 590 kPa与740 kPa，压比小于3，并且排气温度仅为61℃，工况参数良好。同时与传统的R22制冷系统进行对比研究，结果显示，混合制冷剂系统的COP接近于传统R22制冷系统，且在容积制冷效率方面，吸气流量为R22制冷系统一级吸气流量的26.56%，可显著降低系统中选用压缩机的尺寸，系统更加简单，性价比更高。因此，新型的低温混合制冷剂R14/R23/R134a/R245fa具备替代船用传统R22制冷剂的潜力。

According to the "Montreal Protocol", the R22 used in the refrigeration system of fishing vessels needs to be banned before 2030 due to its effect on the depletion of the ozone layer. Therefore, it is imminent to find an ideal alternative refrigerant. By screening and proportioning the components of the mixed refrigerants, it can not only meet the refrigeration requirements, but also meet the environmental requirements, and become the mainstream trend to replace traditional refrigerants. In this paper, a single-stage self-cascading refrigeration system is designed, and the chemical process simulation software is used to carry out the application substitution research of mixed refrigerants. Based on the characteristics of the self-cascading refrigeration system and the thermophysical properties of the mixed refrigerants, R14, R23, R134a, and R245fa, were selected for the target temperature zone of -65 ℃, which were composed of binary, ternary, and quaternary mixed refrigerants respectively. For the self-cascading refrigeration system, the thermodynamic calculation and analysis of binary, ternary and quaternary mixed refrigerants under different components and different concentrations were carried out. The results show that the refrigeration system with quaternary mixed refrigerants is better than that with binary and ternary mixed refrigerants. When the ratio of quaternary refrigerant components is R14/R23/R134a/R245fa (0.35/0.36/0.1/0.19), the COP of the refrigeration system could reach 1.037, the exhaust pressure and the suction pressure are 1590 kPa and 740 kPa respectively, the pressure ratio is less than 3, and the exhaust temperature is only 61℃. Compared with the traditional R22 refrigeration system, the COP of the mixed refrigerant system is close to the traditional R22 refrigeration system. In terms of volume refrigeration efficiency, the suction flow rate is only 26.56% of the first-stage suction flow rate of the R22 refrigeration system, which can reduce the size of the compressor in the system, making the system simpler and more cost-effective. Therefore, the new mixed refrigerants of R14/R23/R134a/R245fa have the potential to replace the traditional refrigerants of R22.