Energy and environmental performances of heat pumps using R32 and R466A as alternatives to R410A

초록

A huge amount of greenhouse gas is emitted from the use of R410A with a global warming potential (GWP) of 2256 in heat pumps. Although the adoption of R32 (GWP=771) as an alternative to R410A can reduce CO2 emissions, it is strictly limited to small heat pumps owing to its flammability. R466A has emerged as an alternative refrigerant to R410A and R32 because of its low GWP and nonflammability. However, experimental studies on the energy and environmental performance of R466A are limited. In this study, the heating and cooling capacities and COPs of water-to-water heat pumps using R466A, R32, and R410A were measured and compared under various inlet water temperatures in the evaporator and condenser. Based on the experiments, R32 and R466A exhibited 20.2 % lower and 6.3 % higher optimal refrigerant charges than R410A, respectively, owing to their densities. Moreover, R466A exhibited a 3 % lower heating capacity and a 3 % higher coefficient of performance (COP) than R410A, whereas R32 exhibited a 3 % higher heating capacity and 3 % lower COP. Moreover, the life cycle climate performance (LCCP) of refrigerants was compared by estimating the indirect and direct emissions through the calculation guideline in the six regions: Seoul, Austin, San Francisco, New York, Pittsburgh, and Saint Paul. R32 can reduce the LCCPs by 3.3-24.7 % compared with R410A owing to its 3 % higher capacity and 20.2 % lower refrigerant charge. Meanwhile, R466A can reduce the LCCPs by- 0.2-23.3 % compared to R410A, owing to its 3 % higher COP and 68 % lower GWP.

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