| 摘要 |
PURPOSE:To prevent sudden deterioration of heat collecting performance due to frosting and permit elongation of operating time as well as the operation under low atmospheric temperature by a method wherein the fin pitch of lower inlet port side of a heat collector is made more dense then the fin pitch of upper outlet port side of the same. CONSTITUTION:Since heat collection in refrigerating cycle is effected by the change of latent heat, the surface temperature of the fin 7 becomes lower than atmospheric temperature by several degrees, therefore, frosting B begins on the surface of the fin 7. Frosting is generated on the surfaces of the tip end part or flat surface part of the fin 7, thereafter, the frost grows gradually at the tip end of the fin 7 as time elapses and the thickness of frost is increased thereby reducing the width of gaps A gradually, however, the fin pitch of upper side of the device is larger than the lower side thereof, therefore, it takes quite long time until the fins are clogged. The upper side of the heat collector 1 is provided with wider fin pitch, therefore, clogging is not caused easily even when the amount of frosting is large. On the contrary, the fin pitch is more dense in the lower side of the collector 1, however, the heat transfer rate of the lower side is lower than the same of the upper side, therefore, the amount of frosting is comparatively small and the degree of clogging is small consequently.
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