Optimum Designing and Exergy Analysis of an Automobile Air Conditioning System using Fixed and Variable Capacity Compressors and low-GWP (global warming potential) Refrigerants

The air conditioning (A/C) system of the cabin is one of the most energy consuming auxiliaries in a vehicle andits optimization is a technological option suitable for achieving fuel consumption reduction in automotive sector.Hence, in this paper, we investigated the numerical model of an automotive air conditioning (AAC) system for the casesof employing fixed and variable capacity compressors (FCC and VCC). A comparative study of the second law ofthermodynamics is presented to determine the possibility of using R1234yf, an environmentally friendly refrigerant, as adrop-in replacement of HFC-134a in automotive air conditioning system. The energy and exergy analysis has beenapplied to the system, and its performance for both compressor operations has been evaluated. The results show thatthe operation with the VCC usually yields a higher COP than the operation with the FCC in expense of a lower coolingcapacity. Furthermore using R1234yf showed a 22% reduction of compressor shaft power with respect to the air cooledcondenser case and significant COP increase

Keywords:

Automobile Air conditioning , R1234yf refrigerant , Exergy , Variable speed Compressor