A comparative study on the performance of HFO-1234yf and HFC-134a as an alternative in automotive air conditioning systems

Highlights: • Performance of automotive an air conditioning system by two refrigerants is studied. • Compressor work for HFO-1234yf refrigerant is higher than HFC-134a refrigerant. • The discharge temperature of compressor and pressure ratio of HFO-1234yf is lower. • In constant mass flow rates, COP of HFO-1234yf is 18% higher than that of HFC-134a. - Abstract: In this study, an automotive air conditioning system is simulated by considering HFO-1234yf (2,3,3,3-tetrafluoropropene) as the drop-in replacement of HFC-134a. The simulated air conditioning system consists of a multi-louvered fin and flat-plate type evaporator, a wobble-plate type compressor, a mini-channel parallel-flow type condenser and a thermostatic expansion valve. The thermodynamic properties of the refrigerants are extracted from the REFPROP 8.0 software, and a computer program is simulated for the thermodynamic analysis. Two different conditions have been considered in this program for the cycle analysis: for the first state, the cooling capacity is taken as constant, and for the second state the refrigerant mass flow rate is considered fixed. The performance characteristics of system including COP and cooling capacity have been studied with changing different parameters. The results show that the refrigerant-side overall heat transfer coefficient of HFO-1234yf is 18–21% lower than that of HFC-134a, and the pressure drop is 24% and 20% smaller than HFC-134a during condensing and evaporating processes, respectively. Also, in a constant cooling capacity, the COP of HFO-1234yf is lower than HFC-134a by 1.3–5%, and in the second case the COP of HFO-1234yf is about 18% higher than that of HFC-134a.