Heat exchanger and refrigeration cycle apparatus

Abstract

A heat exchanger includes a plurality of fins spaced apart from one another in a first direction and a plurality of heat transfer tubes penetrating through the plurality of fins, the plurality of heat transfer tubes being spaced apart from one another in a second direction crossing the first direction. Each of the plurality of fins includes a fin base surface that is flat and a plurality of fin projections. The plurality of fin projections include inner fin projections provided to separately surround each of the plurality of heat transfer tubes, the inner fin projections protruding in the first direction from the fin base surface, and outer fin projections provided to separately surround each of the inner fin projections, the outer fin projections protruding in the first direction from the fin base surface.

1 . A heat exchanger comprising:
 a plurality of fins being spaced apart from one another in a first direction; and   a plurality of heat transfer tubes penetrating through the plurality of fins, the plurality of heat transfer tubes being spaced apart from one another in a second direction crossing the first direction,   wherein   each of the plurality of fins includes
 a fin base surface that is flat, and 
 a plurality of fin projections, and 
   the plurality of fin projections include
 inner fin projections provided to separately surround each of the plurality of heat transfer tubes, the inner fin projections protruding in the first direction from the fin base surface, and 
 outer fin projections provided to separately surround each of the inner fin projections, the outer fin projections protruding in a same direction with the inner fin projections from the fin base surface, and 
   the inner fin projections and the outer fin projections are adjacent to each other without gaps.   
     
     
         2 . The heat exchanger of  claim 1 , wherein
 the plurality of heat transfer tubes are circular in cross-section, and   each of the inner fin projections and a corresponding one of the outer fin projections are provided concentrically with a corresponding one of the plurality of heat transfer tubes.   
     
     
         3 . (canceled) 
     
     
         4 . The heat exchanger of  claim 1 , wherein assuming h1 is a height of each of the inner fin projections from the fin base surface and that h2 is a height of each of the outer fin projections from the fin base surface, a relationship between the height h1 and the height h2 is expressed as h2≤h1. 
     
     
         5 . The heat exchanger of  claim 1 , wherein
 the plurality of heat transfer tubes include a first heat transfer tube and a second heat transfer tube that are adjacent to each other in the second direction,   the inner fin projections include
 a first inner fin projection provided to surround the first heat transfer tube, and 
 a second inner fin projection provided to surround the second heat transfer tube, the outer fin projections include 
 a first outer fin projection provided to surround the first inner fin projection, and 
 a second outer fin projection provided to surround the second inner fin projection, and 
   the fin base surface has a second flat portion between the first outer fin projection and the second outer fin projection.   
     
     
         6 . The heat exchanger of  claim 5 , wherein
 the plurality of fin projections include an intermediate fin projection protruding in the first direction from the fin base surface, and   the intermediate fin projection is provided so that at least part of the intermediate fin projection is located between the first outer fin projection and the second outer fin projection.   
     
     
         7 . The heat exchanger of  claim 6 , wherein in the first direction, a direction in which the inner fin projections protrude from the fin base surface and a direction in which the intermediate fin projection protrudes from the fin base surface are opposite to each other. 
     
     
         8 . The heat exchanger of  claim 6 or 7 , wherein the intermediate fin projection is provided at a position not crossing a center line passing through a center of the first heat transfer tube and a center of the second heat transfer tube along the second direction. 
     
     
         9 . The heat exchanger of  claim 8 , wherein
 assuming that a transverse direction of the plurality of fins is a third direction crossing the first direction and the second direction,   the intermediate fin projection includes
 a first raised portion extending in the second direction, the first raised portion being raised from the fin base surface, and 
 a second raised portion extending parallel to the first raised portion, the second raised portion raised from the fin base surface, 
   in the second direction, the first raised portion is greater in length than the second raised portion,   in the third direction, a distance between the first raised portion and the center line is longer than a distance between the second raised portion and the center line,   in the second direction, the first raised portion includes
 a first end provided adjacent to the first outer fin projection, and 
 a second end provided adjacent to the second outer fin projection, 
   in the second direction, the second raised portion includes
 a first end provided adjacent to the first outer fin projection, and 
 a second end provided adjacent to the second outer fin projection, 
   a first virtual line passing through the first end of the first raised portion and the first end of the second raised portion does not cross the first outer fin projection, and   a second virtual line passing through the second end of the first raised portion and the second end of the second raised portion does not cross the second outer fin projection.   
     
     
         10 . A refrigeration cycle apparatus comprising the heat exchanger of  claim 1  as a condenser or an evaporator.