In Tokyo area, its TEWI dropped by 18% in
comparison with that of R410A and the direct impact portion of R32 decreased to 7% of the total impact. Taira et al.
(2011) proposed a notion of diversity of refrigerant choice, and suggested that R32 is a refrigerant enabling quick
action against global warming. Tu et al. (2011) compared the performance using R32 and R410A in a
thermodynamic model and conducted experiments at different operating conditions in a 3.2 kW residential heat pump unit. Experimental results showed that R32 outperformed R410A by 8% and 3% in cooling and heating
capacities, respectively, and by 3% and 2% in cooling and heating COPs, respectively. Huang et al. (2011) tested an
air-to-water heat pump with tube-bundle-double-pipe heat exchanger. Test results showed that the charge of R32
was 66% of R410A. Cooling performance of R32 was close to that of R410A, and the heating COP was 14% higher
than that of R410A. Bella and Kaemmer (2011) performed the analysis of R32 versus R410A in air conditioning and
heat pump applications with a scroll compressor. They concluded that R32 is ready and could be implemented soon.
They also reported that the application envelope for a heat pump system would be decreased when switching from
R410A to R32.