Experimental study on the pull‐down performance of a −80°C cascade refrigeration freezer

摘要

Abstract To cope with global climate change, chlorofluorocarbons and hydrofluorocarbons refrigerants have been or will be abandoned by different countries worldwide. Natural refrigerants seem to be promising substitutes in the near future. In this study, eco‐friendly refrigerants R290 and R170 are adopted as high‐temperature and low‐temperature fluid in a cascade refrigeration freezer to generate −80°C. The experimental measurements are carried out to investigate the pull‐down performance of the freezer. The inlet and outlet pressure of two compressors are monitored and tested. Temperatures of different state monitors in high‐temperature cycle and low‐temperature cycle are measured to analysis the operation performance of the cascade refrigeration system. Different temperature test points are set to research the temperature drop and temperature distribution in the freezer. Some new findings are obtained. Due to the lack of ultralow temperature experimental data on cascade refrigeration system, this study can enrich and deepen the understanding on operation mechanism of ultralow temperature cascade refrigeration freezer.