Air-conditioner, Heat exchanger, Refrigerant, Low-GWP
Recently several refrigerants have been lined up as candidate alternatives to R410A in order to mitigate further global warming and to promote saving energy. We have selected R32 from among these candidates; however it is important to continue comparing it to other refrigerants in search for an even better choice. Therefore we carried out the drop-in test of the new refrigerant R32/R1234yf/R125(67/26/7) by comparing its COP and compressor discharge temperature etc. to those of R410A, R32/R1234ze(70/30), and R32, using residential mini-split type air conditioner. As a result, we confirm the performance of new refrigerant R32/R1234yf/R125(67/26/7) is not better than that of R32, since they have loss due to refrigerant pressure drop. However the results above are not assumed to be fair since they are obtained by means of heat exchangers optimized for R32. Therefore we evaluate the new refrigerant candidate with optimization of heat exchangers for them by detail simulation including pass configuration. After that, we conclude that R32 is better than other candidate at present.