Study on thermodynamic and environmental effects of vapor compression refrigeration system employing first to next-generation popular refrigerants

Abstract

This paper presents a rigorous exergy analysis of a vapor compression refrigeration system (VCRS) for the AHRI standard cooling operating conditions assessed with a constant cooling load of 50 kW. A comprehensive mathematical model has been developed to evaluate thermodynamic variables of the major components. The analysis is carried out for widely used refrigerants, namely R12, R22, R134a, R152a, R410A; next-generation low GWP refrigerants R32, R1234yf, R1234ze(E); and two natural refrigerants R600a and R744 (CO2). First law analysis and exergetic efficiency at cycle and component level are investigated for all the refrigerants. The results indicate that R600a is the best, followed by R152a, R1234ze(E), and R1234yf in terms of COP, total exergy destruction, and exergetic efficiency. Moreover, the total equivalent warming impact (TEWI), which is the aggregation of direct impact due to refrigerant leakage and indirect impact due to electricity usage, from each system has also been assessed. The lowest and highest amount of TEWI has been found for R600a and R12 systems, respectively. This study also indicates that CO2 is a prospective future refrigerant for its lower emission, affordability, availability, non-toxicity, non-flammability, and system compactness when the VCRS is powered by electricity generated from nuclear/renewable sources.