Theoretical investigation of low global warming potential blends replacing R404A: the simple refrigeration cycle and its modifications

Abstract

R404A refrigerant is one of the most widely used hydrofluorocarbons in the commercial refrigeration industry for low and medium temperatures. However, this refrigerant contributes negatively to the environment due to its high global warming potential (GWP = 3943), and for several years, it has been labeled as one of the refrigerants that should be phased out. The present study theoretically evaluates low-GWP refrigerants as a replacement alternative to R404A, including R407H, R442A, R449A, R454A, R454C, R455A, R459B, and R465A. The analysis focuses on the comparison between relative differences in the volumetric flow in the compressor suction and the coefficient of performance for four configurations of the vapor compression cycle, such as the basic cycle, the cycle with an internal heat exchanger, the cycle with direct injection, and the cycle with a sub-cooler. According to the proposed operating conditions of evaporation temperature (−10°C and −40°C) and condensation temperature (40°C and 55°C), R454A could be the best long-term replacement option for its low GWP, energy performance, and direct fit for any configuration. R459B could also be considered a viable option, but with certain design modifications. On the contrary, the refrigerants R465A, R455A, and R454C would be discarded because they present a greater non-adaptation to the compressor in each configuration analyzed.