A Study on Change of the Shape and Size of the Minichannel Evaporators to Enhance the Cooling Capacity of the CO&underscore;2 Air Conditioning Cycle

An experimental on the change of the shape and size of the minichannel evaporators to increase the cooling capacity of the CO2 air conditioning cycle was carried out. Two minichannel evaporators with the same heat transfer area were designed with different channel lengths. In this study, the ambient temperature was tested for both evaporators at 32.5°C. For both cases, the cooler pressure and evaporator pressure are 77 bar and 42 bar, respectively. The results show that the cooling capacity of the evaporator E2 (shorter length) is 6.6 better than that obtained from the evaporator E1 (longer length): the air outlet temperature of E2 is 1.4°C lower than that of E1. In addition, the temperature distribution of the evaporator E2 is better than that of the evaporator E1. The study also concluded that the COP of the E2 is 0.22 larger than that obtained from the E1.