Estudio de diferentes alternativas de refrigerantes al R-134A para el aire acondicionado automotriz que trabaja en ciclos subcríticos

Abstract

This study presents a thermodynamic analysis of various refrigerants based on the vapor compression refrigeration cycle. The objective of this research is to numerically find the alternative refrigerant to R-134a by modeling the vapor compression cycle using the EES (Engineering Equation Solver) software, the heat exchangers were modeled using the ε-NTU (Number of Units) method. of heat transfer), in which they were divided by zones, the compressor was modeled using the efficiency curves. For the validation of the model, experimental data from similar air conditioning systems were used, which allowed representation of the real behavior of the system. The thermodynamic comparison of the vapor compression cycle was carried out for all the refrigerant alternatives. Performance parameters include COP (Coefficient of Performance), refrigeration capacity, compressor input power, and discharge temperature. These parameters are calculated at different rotating speeds of the compressor, condenser temperatures of 13.5℃,17℃ and 21℃, and evaporator temperatures of 25℃,35℃,45℃,55℃ and 65℃. The R-152a refrigerant showed a 7% increase in the COP (Coefficient of Performance), the R-1234yf refrigerant showed a 9% decrease in the COP (Coefficient of Performance), the R-410A and R-32 refrigerants presented a drastic departure from R-134a. R-152a was determined to be a refrigerant that can be used as a drop-in replacement, R-1234yf and R-290 refrigerants can be used as alternatives, but consideration should be given to making modifications to the compressor or evaporator geometry. Finally, it is recommended to develop the modeling independently for the system components and each of the refrigerants since they have different characteristics.