Abstract
In order to achieve ultra-low temperature system below -70℃, the CO2 refrigeration system with a cyclone separation evaporator, that separates dry ice, utilizes the sublimation heat of the dry ice generated during the expansion process. The system proves a useful refrigeration system with cold energy storage function compared to that of the conventionally used horizontal evaporator (CHE) system. In this study, the effect of the ethanol circulation system, which is installed as a secondary chiller on the cascade heat pump cycle, is investigated experimentally, and the basic performance of the ethanol circulation system is reported in details.