Automotive air conditioning systems are essential for ensuring thermal comfort
for passengers. However, these systems require the elimination of refrigerants
with high Global Warming Potential (GWP) and a transition toward more
environmentally friendly alternatives. For many years, R134a has been the
industry standard in automotive applications, following the phase-out of
chlorofluorocarbons (CFCs) such as R12. This study evaluates the energy
efficiency and environmental impact of several refrigerants in automotive air
conditioning systems in tropical climates. A comprehensive literature review is
conducted to select the refrigerants to be compared with R134a. The following is
chosen: R1234yf, R744 (CO2), R290, R600a and R152a. Then a
mathematical model is prepared and validated. The deviation between the results
presented by the mathematical model and those in the literature varies from
-1.21% to 8.33%. The simulation results suggest that the Coefficient of
Performance (COP) of R152a and R600a is approximately 3% higher than that of
R134a. However, these fluids are flammable, requiring additional safety
investments. While R1234yf shows a slight loss in efficiency, at almost 4% lower
than R134a, it offers a degree of compatibility due to its similar overall
properties. The performance of R290 is slightly worse, while that of R744 is
significantly lower. Finally, the environmental analysis based on TEWI indicates
that R152a and R600a result in a slightly lower impact compared to R134a. In
contrast, R290 and R1234yf exhibit a slightly higher environmental impact than
R134a.