2022 Volume 39 Issue 2 Pages 117-
CO2 is a promising refrigerant due to its low environmental impact and low toxicity. In the present study, ultra-low temperature refrigeration technology using CO2 heat pump system is introduced with newly developed cyclone separator-evaporator. In the installation phase of the actual refrigeration system, internal blockage was observed in the flow path of dry ice in a horizontal evaporator, which is modeled after a general-purpose evaporator. It was shown that the blockage phenomena caused to reduce the performance of the system as thermal resistance. In order to solve the problem of internal blockage and to improve the performance of evaporator, we introduced a cyclone separator-evaporator is designed and installed in the actual refrigeration system. The newly developed cyclone separator-evaporator is a combination of a cyclone separator part and an evaporator function part. As a result of evaluating the refrigeration system performance using a cyclone separator-evaporator, it is found that the system achieved high efficiency in the low temperature of -67°C and COPsystem of 1.2. The system performance is expected to be significantly improved compared to the system using a horizontal evaporator.
