18 May 2017

O.4.2.5 Evaluation of Performance for Heat Pump System using Low GWP Refrigerants in High Ambient Temperature

The refrigerant R32 has a relatively low GWP that contributes to the prevention of global warming, also has a better COP than conventional R410A in air conditioning equipments. R32 was selected as the alternative for R410A for mini-split air-conditioners/heat pumps. After being introduced by all manufacturers in Japan, it started to be introduced by major manufacturers in Asia, Europe, Australia, and so on.
Recently several new alternatives for R410A have been proposed in order to achieve similar capacity to that of R410A and mitigate high discharge temperature issue of R32 as well as to reduce energy consumption. We selected R32 and brought our products to the market since 2012. However, it is important to continue the search for new and better candidates.
We carried out performance comparison for the lower GWP refrigerant R452B and R32. We also conducted the experiments in cooling operation in high ambient temperature. As the result, we found that the COP of R32 is superior to R452B because of its latent heat characteristic. In particular, as condensing temperature increases such as in high ambient temperature operation, latent heat of R452B becomes smaller. Therefore, advantage of R32 in COP becomes more significant in high ambient condition.
From the above, we consider that R32 is still the best refrigerant at present. However, we will continue investigation in search for a better refrigerant.