A comparative energy, exergy, and environmental impact analysis of R134A and R513B refrigerants in cooling systems

Cooling systems hold an indispensable role in contemporary industries, with vapor compression refrigeration methods being among the most widely adopted applications. Although the refrigerant R134a is commonly preferred in these systems due to its high efficiency, it is scheduled to be phased out because of its high global warming potential (GWP). This situation necessitates the development of environmentally friendly and sustainable alternative refrigerants, thereby underscoring the significance of innovative solutions in this field. In this study, the performance of the next-generation refrigerant R513B — a mixture of R134a and R1234yf (41.5/58.5) — was investigated as an alternative to R134a, through both experimental and theoretical approaches. A vapor compression refrigeration system compatible with R134a, operating in a water-to-water configuration and equipped with frequency control, was designed for this purpose. Experimental investigations were conducted for R134a and R513B at various evaporator temperatures (20, 15, 10°C), condenser temperatures (20, 30, 35°C), and compressor frequencies (40, 45, 50, 55, 60 Hz). Comparative analyses of energy performance, exergy efficiency, and environmental impact were carried out based on both theoretical and experimental data. The theoretical analysis revealed that the coefficient of performance (COP) of R134a was approximately %2 higher than that of R513B, whereas the experimental analysis indicated a greater discrepancy of approximately %15. Furthermore, it was observed in the experimental results that increasing compressor frequency led to a decrease in COP. Exergy analyses demonstrated that both refrigerants exhibited comparable exergy efficiencies. From an environmental perspective, life cycle climate performance analysis revealed a %6.88 difference between R134a and R513B. These findings highlight the critical importance of developing new refrigerants to achieve environmental sustainability.