Experimental study of automotive air conditioning systems using CO2 as a refrigerant.

In the study, the authors wrestled with increasing the COP of automotive air conditioning systems using CO2 as a refrigerant. As a result, under cooling conditions, they achieved lower annual energy consumption with automotive air conditioning systems using CO2 than with conventional systems using HFC-134a, by improving the gas cooler and the evaporator, and adopting an inner heat exchanger.