Air-conditioning apparatus

Abstract

In an air-conditioning apparatus including a heat exchanger to switch between serving as an evaporator and serving as a condenser, the heat exchanger includes a first heat exchanger, a second heat exchanger, and a connection pipe. The first heat exchanger includes a first header divided into a plurality of chambers and connected with one end of each of the first heat transfer tubes, and a second header extending in a horizontal direction and connected with the other end of each of the first heat transfer tubes. The second heat exchanger includes a plurality of second heat transfer tubes, a third header extending in the horizontal direction and connected with one end of each of the second heat transfer tubes, and a fourth header extending in the horizontal direction and connected with the other end of each of the second heat transfer tubes.

1 . An air-conditioning apparatus in which a compressor, a condenser, a pressure reducing device, and an evaporator are connected by a pipe and in which refrigerant circulates, the air-conditioning apparatus comprising:
 a heat exchanger configured to, in response to switching of directions of refrigerant flow, switch between serving as the evaporator and serving as the condenser; and   a fan configured to generate an air flow to send air to the heat exchanger,   wherein the heat exchanger includes
 a first heat exchanger including
 a plurality of first heat transfer tubes, 
 a first header extending in a horizontal direction, the first header having an internal space divided into a plurality of chambers including a first chamber and a second chamber, the first header being connected with one end of each of the plurality of first heat transfer tubes, and 
 a second header extending in the horizontal direction, the second header being connected with an other end of each of the plurality of first heat transfer tubes, 
 
 a second heat exchanger including
 a plurality of second heat transfer tubes, 
 a third header extending in the horizontal direction, the third header being connected with one end of each of the plurality of second heat transfer tubes, and 
 a fourth header extending in the horizontal direction, the fourth header being connected with an other end of each of the plurality of second heat transfer tubes, and 
 
 a connection pipe connecting one of the first header and the second header of the first heat exchanger, and the third header of the second heat exchanger, 
   wherein for an operation in which the heat exchanger is made to serve as the evaporator,
 the plurality of first heat transfer tubes are connected such that, after refrigerant to be evaporated enters the first chamber of the first header from the pipe, the refrigerant flows to the second header, and then flows from the second header to the second chamber of the first header, 
 the plurality of second heat transfer tubes are connected such that, after the refrigerant passes through the first heat exchanger, the refrigerant flows via the connection pipe into the third header of the second heat exchanger, and then flows from the third header to the fourth header, and further, 
 the pipe is connected such that, after the refrigerant passes through the second heat exchanger, the refrigerant is sucked into the compressor, 
   wherein for an operation in which the heat exchanger is made to serve as the condenser,
 the pipe is connected such that, after refrigerant to be condensed passes through the second heat exchanger from the pipe, the refrigerant flows via the connection pipe into one of the plurality of chambers of the first header of the first heat exchanger, or into the second header, and after passing through the first heat exchanger, the refrigerant exits from the first chamber of the first header, and 
   wherein the plurality of first heat transfer tubes each have a length greater than a length of each of the plurality of second heat transfer tubes.   
     
     
         2 . The air-conditioning apparatus of  claim 1 ,
 wherein the second header and the third header each have an internal space divided into a plurality of chambers, and   wherein the connection pipe connects: one of the plurality of chambers of the first header, or one of the plurality of chambers of the second header; and one of the plurality of chambers of the third header.   
     
     
         3 . The air-conditioning apparatus of  claim 2 , wherein the internal space of the first header or the second header includes a number of chambers connected to the connection pipe greater than a number of chambers in the internal space of the third header that are connected to the connection pipe. 
     
     
         4 . The air-conditioning apparatus of  claim 1 , wherein the first chamber of the first header is smaller than the second chamber. 
     
     
         5 . The air-conditioning apparatus of  claim 1 , wherein the internal space of the third header is divided into the plurality of chambers that are equal in size. 
     
     
         6 . The air-conditioning apparatus of  claim 1 , wherein a lowermost part of the first heat exchanger is located lower in a vertical direction than is a lowermost part of the second heat exchanger. 
     
     
         7 . The air-conditioning apparatus of  claim 1 ,
 wherein the first chamber of the first header is a chamber located at one end of the first header in the horizontal direction, and   wherein the connection pipe connects: one of the plurality of chambers of the first header that is located at an other end in the horizontal direction, or one of the plurality of chambers of the second header that is located at an other end in the horizontal direction; and the third header.   
     
     
         8 . The air-conditioning apparatus of  claim 1 , wherein when:
 with the plurality of first heat transfer tubes being divided into a plurality of groups such that a first heat transfer tube and another first heat transfer tube belong to a same group if a chamber of the first header to which the first heat transfer tube and the another first heat transfer tube are connected at one end, and a chamber of the second header to which the first heat transfer tube and the another first heat transfer tube are connected at an other end are same between the first heat transfer tube and the another first heat transfer tube, and belong to different groups if a chamber of the first header to which the first heat transfer tube and the another first heat transfer tube are connected at one end, and a chamber of the second header to which the first heat transfer tube and the another first heat transfer tube are connected at an other end are different between the first heat transfer tube and the another first heat transfer tube, the first heat exchanger has a mean number of branches N1, the mean number of branches N1 being determined by summing, for all of the plurality of groups, a square of a number of the first heat transfer tubes in each of the plurality of groups to obtain a sum total, and dividing the sum total by a total number of the first heat transfer tubes in all of the plurality of groups;   with the plurality of second heat transfer tubes being divided into a plurality of groups such that a second heat transfer tube and another second heat transfer tube belong to a same group if a chamber of the third header to which the second heat transfer tube and the another second heat transfer tube are connected at one end, and a chamber of the fourth header to which the second heat transfer tube and the another second heat transfer tube are connected at an other end are same between the second heat transfer tube and the another second heat transfer tube, and belong to different groups if a chamber of the third header to which the second heat transfer tube and the another second heat transfer tube are connected at one end, and a chamber of the fourth header to which the second heat transfer tube and the another second heat transfer tube are connected at an other end are different between the second heat transfer tube and the another second heat transfer tube, the second heat exchanger has a mean number of branches N2, the mean number of branches N2 being determined by summing, for all of the plurality of groups, a square of a number of the second heat transfer tubes in each of the plurality of groups to obtain a sum total, and dividing the sum total by a total number of the second heat transfer tubes in all of the plurality of groups; and   each of the plurality of first heat transfer tubes has a length L1, and each of the plurality of second heat transfer tubes has a length L2,   (L1/N1)×(N2/L2) is in a range of 1.3 to 5.2.   
     
     
         9 . The air-conditioning apparatus of  claim 1 ,
 wherein the fan is a fan with a blade that rotates around a rotation axis of the fan, and   wherein when viewed in a direction of the rotation axis, the first heat exchanger and the second heat exchanger are disposed at locations around the rotation axis that do no overlap each other.   
     
     
         10 . The air-conditioning apparatus of  claim 1 ,
 wherein the fan is an axial-flow fan,   wherein the first header, the second header, the third header, and the fourth header extend in a direction tangential to a circle centered on the rotation axis of the fan, and   wherein when seen in plan view in a plane orthogonal to the rotation axis, the first heat exchanger and the second heat exchanger are disposed at locations that do not overlap each other.   
     
     
         11 . The air-conditioning apparatus of  claim 1 ,
 wherein the fan is a centrifugal fan including a scroll casing,   wherein each of the plurality of first heat transfer tubes, and each of the plurality of second heat transfer tubes extend in a direction orthogonal to a rotation axis of the fan,   wherein the first header, the second header, the third header, and the fourth header extend in a direction parallel to a direction of the rotation axis, and   wherein in a plane orthogonal to the rotation axis, as viewed in a winding direction of the scroll casing, the second heat exchanger is located closer to a winding start position of the scroll casing than is the first heat exchanger.   
     
     
         12 . The air-conditioning apparatus of  claim 1 , wherein the first heat exchanger and the second heat exchanger are mounted in an indoor unit. 
     
     
         13 . The air-conditioning apparatus of  claim 1 , wherein the refrigerant is an olefin-based refrigerant, propane, or dimethyl ether, and has a low gas density relative to an R32 refrigerant or an R410A refrigerant. 
     
     
         14 . The air-conditioning apparatus of  claim 1 ,
 wherein the air-conditioning apparatus comprises the compressor, a use-side heat exchanger, an expansion device, and a heat-source-side heat exchanger,   wherein the compressor comprises at least one compressor, and   wherein at least one of the use-side heat exchanger or the heat-source-side heat exchanger includes the first heat exchanger and the second heat exchanger.