Abstract
In relation to the efficiency of heat pump system, basic experimental researches have been carried out on frosting and defrosting phenomena under forced convection at various level of humidity. Effects of surface properties on frosting and defrosting phenomena were investigated. Copper fin is coated by hydrophobic paint. In frosting process, surface temperature of coated fin showed higher temperature, compared with uncoated fin due to the thermal resistance of the coated material. Using hydrophobic paint mixed with material having high thermal conductivity, temperature rise of coated fin is considerably suppressed. At early stage of frosting process, configuration of frozen droplets at cooled fin is considerably different between coated fin and uncoated fin. Time needed for defrosting process is shortened about 30seconds for coated fin compared with uncoated fin.
