Air conditioner

Abstract

An air conditioner includes an outdoor unit including a first heat exchanger and an indoor unit including a second heat exchanger. The first heat exchanger includes a first heat transfer tube and a plurality of first fins. The second heat exchanger includes a second heat transfer tube and a plurality of second fins. The first heat transfer tube, the first fins, the second heat transfer tube, and the second fins are made of aluminum or an aluminum alloy. A first sacrificial layer is provided on a surface of the first heat transfer tube. The first sacrificial layer is lower in potential than a base material of the first heat transfer tube and lower in potential than the first fins. A fin pitch of the first fins is larger than a fin pitch of the second fins.

1 . An air conditioner comprising:
 an outdoor unit including a first heat exchanger having
 a first heat transfer tube made of aluminum or an aluminum alloy, and 
 a plurality of first fins made of aluminum or an aluminum alloy; and 
   an indoor unit including a second heat exchanger having   a second heat transfer tube made of aluminum or an aluminum alloy, and
 a plurality of second fins made of aluminum or an aluminum alloy, wherein 
 a first sacrificial layer that is lower in potential than a base material of the first heat transfer tube and lower in potential than the first fins is provided on a surface of the first heat transfer tube, and 
   a fin pitch of the first fins is larger than a fin pitch of the second fins.   
     
     
         2 . The air conditioner according to  claim 1 , wherein the first heat transfer tube and the second heat transfer tube have a cylindrical shape. 
     
     
         3 . The air conditioner according to  claim 1 , wherein a first surface layer containing a resin is provided on a surface of the first fin. 
     
     
         4 . The air conditioner according to  claim 3 , wherein
 a second surface layer containing a resin is provided on a surface of the second fin, and   a thickness of the first surface layer is larger than a thickness of the second surface layer.   
     
     
         5 . The air conditioner according to  claim 1 , wherein a second sacrificial layer that is lower in potential than a base material of the second heat transfer tube and lower in potential than the second fin is provided on a surface of the second heat transfer tube. 
     
     
         6 . The air conditioner according to  claim 1 , wherein a difference between the fin pitch of the first fins and the fin pitch of the second fins is 0.1 mm or more and 0.3 mm or less. 
     
     
         7 . The air conditioner according to  claim 1 , wherein the fin pitch of the first fins is more than 1.0 times and less than 1.3 times the fin pitch of the second fins. 
     
     
         8 . The air conditioner according to  claim 1 , wherein
 the second sacrificial layer that is lower in potential than the base material of the second heat transfer tube is provided on the surface of the second heat transfer tube, and   a thickness of the first sacrificial layer and a thickness of the second sacrificial layer are same.   
     
     
         9 . The air conditioner according to  claim 1 , wherein an outer diameter of the first heat transfer tube and an outer diameter of the second heat transfer tube are same. 
     
     
         10 . The air conditioner according to  claim 1 , wherein a material of the first heat transfer tube and a material of the second heat transfer tube are same. 
     
     
         11 . The air conditioner according to  claim 1 , wherein
 the outdoor unit further includes a first drain pan that receives water,   the indoor unit further includes a second drain pan that receives water,   a plurality of the first heat transfer tubes and a plurality of the second heat transfer tubes are provided,   a lowermost end of the plurality of first heat transfer tubes is located above a water level of the first drain pan, and   a lowermost end of the plurality of second heat transfer tubes is located above a water level of the second drain pan.   
     
     
         12 . The air conditioner according to  claim 1 , wherein
 the plurality of first fins is stacked in a first direction in which the first heat transfer tube extends and includes a first collar through which the first heat transfer tube passes,   the first collar includes
 a first upright portion extending in the first direction from a fin body, 
 a flat portion extending from the first upright portion toward the first heat transfer tube, 
 a second upright portion extending from the flat portion along the first heat transfer tube, and 
 a flange extending outward from the second upright portion, 
   one of the flat portions is in contact with the flange of another adjacent first fin of the first fins, and
 the plurality of second fins is stacked in a second direction in which the second heat transfer tube extends and includes a second collar through which the second heat transfer tube passes, 
   the second collar includes
 a first upright portion extending from the fin body in the second direction, 
 a flat portion extending from the second upright portion toward the second heat transfer tube, 
 a second upright portion extending from the flat portion along the second heat transfer tube, and 
 a flange extending outward from the second upright portion, and 
   one of the flat portions is in contact with the flange of another adjacent second fin of the second fins.   
     
     
         13 . The air conditioner according to  claim 1 , wherein
 the plurality of first fins is stacked in a first direction in which the first heat transfer tube extends, and includes a first collar through which the first heat transfer tube passes, and   the first collar includes
 a second upright portion extending along the first heat transfer tube, and 
 a flange extending outward from the second upright portion, 
 the plurality of second fins is stacked in a second direction in which the second heat transfer tube extends and includes a second collar through which the second heat transfer tube passes, 
   the second collar includes
 a second upright portion extending along the second heat transfer tube, and 
 a flange extending outward from the second upright portion, and 
   a coupling portion between the second upright portion and the flange of each of the first collar and the second collar has a curved shape having a curvature radius of 0.2 mm or more.   
     
     
         14 . The air conditioner according to  claim 1 , wherein a second sacrificial layer that is lower in potential than a base material of the second heat transfer tube and higher in potential than the second fin is provided on a surface of the second heat transfer tube. 
     
     
         15 . The air conditioner according to  claim 1 , wherein a rate of zinc content of the first fin is higher than a rate of zinc content of the second fin. 
     
     
         16 . The air conditioner according to  claim 2 , wherein a first surface layer containing a resin is provided on a surface of the first fin. 
     
     
         17 . The air conditioner according to  claim 2 , wherein a second sacrificial layer that is lower in potential than a base material of the second heat transfer tube and lower in potential than the second fin is provided on a surface of the second heat transfer tube. 
     
     
         18 . The air conditioner according to  claim 3 , wherein a second sacrificial layer that is lower in potential than a base material of the second heat transfer tube and lower in potential than the second fin is provided on a surface of the second heat transfer tube. 
     
     
         19 . The air conditioner according to  claim 4 , wherein a second sacrificial layer that is lower in potential than a base material of the second heat transfer tube and lower in potential than the second fin is provided on a surface of the second heat transfer tube. 
     
     
         20 . The air conditioner according to  claim 2 , wherein a difference between the fin pitch of the first fins and the fin pitch of the second fins is 0.1 mm or more and 0.3 mm or less.