The impact of R50 on −100°C three-stage auto-cascade refrigeration system

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.