Energy, exergy, and environmental analysis of five low-GWP refrigerants considered as alternatives to R410A for air conditioning systems

Abstract

The sustainability concern of high Global Warming Potential (GWP) refrigerants like R410A has spurred universal efforts in searching for low-GWP replacements in vapor-compression air conditioning systems. This study undertakes a comprehensive energy, exergy, and environmental analysis of five low-GWP refrigerants R32, R290, R454B, R454C, and R513A to be used as alternatives to R410A. A model of a single-stage vapor compression cycle was constructed and simulated with Engineering Equation Solver (EES) with real fluid property data under steady-state conditions. Simulation was undertaken using evaporating temperatures of –5 °C to 5 °C and condensing temperatures of 30 °C to 50 °C with fixed subcooling (5 K) and superheat (7 K) values. To maintain accuracy and credibility, the model was checked against literature data of experiments under similar working conditions with deviation of less than 10% in mass flow rate, discharge temperature, cooling capacity, power to compressor, and Coefficient of Performance (COP). From the analysis, it is found that R290 has the best thermodynamic performance with an optimal COP value of 7.91, 5.6% better than R410A and an optimal cooling capacity of 4.30 kW, 19.3% greater than R410A. It achieves the highest exergy efficiency of 0.52 and the lowest exergy destruction in components. R454B, with slightly lower COP performance, has the lowest Total Equivalent Warming Impact (TEWI) of 13.3 tons CO₂, which is some 16% less than R410A. On the other hand, R454C has the highest exergy destruction of 120.4 W and TEWI of 18.4 tons CO₂. R290 and R454B are thus found to be the best low-GWP options to fulfill the transition to environment-friendly and energy-efficient air conditioning systems.