In this paper, a -100°C three-stage auto-cascade refrigeration system is proposed and the experimental device is established. In order to determine the impact of R50 on the refrigeration cycle, the experiments are made by using mixed-refrigerants with R134a/R23/R14 and R134a/R23/R14/R50 containing the same quantity of R134a, R23 and R14 respectively in the same device. By analyzing and comparing the different effects of the two experiments, it is found that when R50 is added into the mixed-refrigerants, the evaporation temperature and the temperature after condensation at the second-stage and the third-stage partial condensers are lower, but the high pressure is increased. The higher the hige pressure is, the more power consumption is needed and more time is required to achieve the designed temperature. So it is harmful to the cycle performance of the three-stage auto-cascade refrigeration system when R50 is added into the mixed-refrigerants.

In this paper the auto-cascade refrigerating system by using mixed-refrigerant in -100°C temperature rang is proposed and the corresponding experimental device is established, then the corresponding experiments are conducted. Based on the calculation, the best ratios of three-stage and four-stage autocascade refrigeration system are respectively obtained through many experiments. Then the performance comparison of three-stage and four-stage auto-cascade refrigeration system is obtained. © Sila Science. All rights reserved.

为了确定R50对-100℃温区三级自动复叠系统中后期运行状态的影响,分别以R134a/R23/R14、R134a/R23/R14/R50为混合工质在同一台实验装置上进行两次试验,其中R134a、R23、R14组分充注量相同。通过对两组工质进行实验和对比分析,发现添加R50时第二、三级分凝器蒸发温度和冷却后温度更低,但是系统压力明显更高,设备耗能增加,达到设计温度所需时间增长,因此在-100℃温区的自动复叠系统混合组分添加R50会对系统的性能不利。