Conventionally, a method for coating a surface with a hydrophilic resin is used for the fin of the heat exchanger of an air conditioner, etc. in order to more readily eliminate dew condensation water during operation. However, with traditional methods for making a surface hydrophilic, dew condenses and freezes, i.e., frost forms, particularly during winter in cold environments. This frozen water is difficult to eliminate and reduces operating efficiency. In fact, air conditioning operation must be occasionally stopped to melt and remove the frost which builds up.
Thus, both an extra heater, and enregy it uses, is required for removing frost. Also, such a process is not desired as air conditioning operation must be occasionally stopped.