Exergetic Investigation of a R1234yf Automotive Air Conditioning System with Internal Heat Exchanger

This experimental study presents the exergetic investigation of an automotive air conditioning (AAC) system with the refrigerant R1234yf. The air-conditioning system is based on the conventional mechanical compression refrigeration cycle. An internal heat exchanger (IHX) has been added to the system in order to provide performance enhancement. The influence of the IHX was investigated at different compressor speeds and air stream temperatures. Experimental measurements were controlled by using a data-acquisition system. The exergy destruction, exergy efficiency and the total exergy destruction per cooling capacity were calculated. The analysis results were compared with a baseline system which operates with the refrigerant R134a. Furthermore, an empirical correlation was proposed for the determination of the total exergy destruction per cooling capacity for various compressor speeds for evaluating the system performance. The exergetic efficiency of the system was improved by introducing IHX. Moreover, it was observed that the temperature rise in the air stream decreased the exergy efficiency and increased the total exergy destruction per cooling capacity.