Performance of low-GWP zeotropic refrigerants R454C and R455A in a medium temperature display case.

The refrigeration industry is looking to replace existing refrigerants such as R404A (GWP=3922) with more environmentally sustainable refrigerants as dictated by regulations. The two leading low-GWP refrigerant (GWP<150) options that can match R404A's performance are R454C and R455A. R454C and R455A are class A2L refrigerants with high evaporator glides of about 5 °C and 6.5 °C, respectively. Thermodynamic cycle assessment for medium temperature refrigeration shows that R455A offers higher cooling capacity than R454C but lower COP. However, the literature suggests that without heat exchanger optimization, glide can significantly impact system performance, reduce cooling capacity, impact optimal superheat and subcool control, and ultimately affect system efficiency. This study reports both refrigerants' drop-in performance in an R404A medium-temperature display case with a remote condenser. Results show that both refrigerants have very similar performance.