Numerical study on heat transfer performance of micro-channel gas coolers for automobile CO2 heat pump systems
Abstract This study aims to investigate the supercritical heat transfer characteristics of compact micro-channel gas coolers applied in automobile CO2 heat pump systems. A simulation model of automobile gas cooler was developed by using segment-by-segment method, and validated by experimental results. Using this model, under the typical heat pump operation conditions, the temperature distributions along the CO2 refrigerant flow path were predicted, and the variation of heat transfer coefficient was analyzed. Furthermore, the impacts of operation conditions such as refrigerant inlet pressure and temperature, as well as configuration parameters such as depth and pass number on the heating performance were discussed. Results show that the established model has a good prediction accuracy for heating capacity of gas cooler. It is found that there is unfavorable air temperature inhomogeneity on the airside outlet surface of gas cooler.