R22 (HCFC22) has been widely used as the refrigerant in refrigerators and air conditioners. According to the Montreal protocol for ozone layer protection, the total amount of HCFCs was capped from the beginning of 1996. Zeotropic refrigerant mixture R407C and azeotropic refrigerant mixture R410A have been selected as the promising alternative refrigerants of R22. This paper examined the passage of R407C refrigerant in heat exchangers through simulation, and obtained the following results. In the heat exchangers used in heat pump type room air conditioners, a counter flow configuration when operating as condenser had high efficiency. In outdoor heat exchangers operating as evaporators, a configuration that restrained temperature glide by partly reducing refrigerant passage had not only high efficiency but also reduced the formation of frost on coils.
