PURPOSE: To improve drain performance upon defrosting and shorten defrosting time, by a method wherein fins are provided with cut-and-raised parts in the downstream direction of the flow of air while the cut-and-raised parts are slanted downwardly with respect to the vertical direction.
CONSTITUTION: A fin 1 is fitted to a heat transfer tube 2. Cut-and-raised parts 4 on the surface of the fin 1 are provided downstream in the direction of airflow 5 and are slanted downwardly with respect to the vertical direction by an attack angle γ; therefore, the flow of air 5 is disturbed properly and the mixing of air is promoted, whereby a high heat transfer coefficient may be maintained. Further, frost is melted upon defrosting into water; however, the cut-and-raised parts 4 are provided in the downstream direction of the airflow 5 and are slanted downwardly with respect to the vertical direction; therefore, water drops quickly and water cutting performance may be promoted. As a result, a defrosting time may be shortened. Further, the freezing of remaining moisture may be restrained when room heating operation is started again.
MIYAGI MASAHIRO
ITO MASAAKI
