Heat exchanger and refrigeration cycle apparatus including same

Abstract

A heat exchanger in which inner wall surfaces of refrigerant passages through which a first refrigerant and a second refrigerant flow are constituted by a different metal and in which a heat exchange performance is improved. Second-refrigerant heat-transfer tubes that are formed with a metal different from a heat transfer block are each inserted through a corresponding second-refrigerant heat-transfer-tube insertion hole. The second-refrigerant heat-transfer tubes are formed with a metal with a different material from that of the heat transfer block.

1 - 20 . (canceled) 
     
     
         21 . A heat exchanger, comprising:
 a heat transfer block made of metal and formed by being penetrated by a first-refrigerant passage group, the first-refrigerant passage group including a plurality of first-refrigerant passages through which a first refrigerant flows, the first-refrigerant passages arranged in parallel to one another and in a row;   second-refrigerant heat-transfer tubes made of metal different from that of the heat transfer block and configured to constitute a second-refrigerant passage group including a plurality of second-refrigerant passages through which a second refrigerant flows, the second-refrigerant heat-transfer tubes being inserted through a plurality of second-refrigerant heat-transfer-tube insertion holes formed in parallel and in a row so as to be adjacent to the first-refrigerant passage group, the second-refrigerant heat-transfer-tube insertion holes being formed by penetrating through the heat transfer block;   second-refrigerant communicating header pipes configured to constitute second-refrigerant communicating portions, the second-refrigerant communicating header pipes being joined to respective both ends of the second-refrigerant heat-transfer tubes along a row direction of the plurality of the second-refrigerant heat-transfer tubes so as to be in communication with all of the second-refrigerant heat-transfer tubes; and   first-refrigerant communicating holes formed at both ends of the first-refrigerant passage group in a refrigerant flow direction in heat transfer block along a row direction of the plurality of the first-refrigerant passages, the first-refrigerant communicating holes being in communication with the plurality of the first-refrigerant passages, wherein   the first refrigerant flows in and flows out of the first-refrigerant communicating holes and flows through the first-refrigerant passage group,   the second refrigerant flows in and flows out of the second-refrigerant communicating portions and flows through the second-refrigerant passage group,   flow directions of the first-refrigerant passage group and the second-refrigerant passage group are parallel, the first-refrigerant passage group and the second-refrigerant passage group being arranged adjacent to each other with a partition wall therebetween and exchanging heat between the first refrigerant and the second refrigerant over the partition wall, and   an inner wall surface of the first-refrigerant passages and an inner wall surface of the second-refrigerant passages are made of different types of metals each other.   
     
     
         22 . The heat exchanger of  claim 21 , wherein each second-refrigerant heat-transfer tube that has been inserted through a corresponding second-refrigerant heat-transfer-tube insertion hole is expanded and is joined to an inner wall surface of the second-refrigerant heat-transfer-tube insertion hole. 
     
     
         23 . The heat exchanger of  claim 21 , wherein concave-convex grooves are formed on an inner surface of each of the second-refrigerant heat-transfer-tube insertion holes. 
     
     
         24 . The heat exchanger of  claim 21 , wherein
 a brazing-material installation groove for disposing a brazing material is formed on an inner surface of each of the second-refrigerant heat-transfer-tube insertion holes in a longitudinal direction thereof, and   each second-refrigerant heat-transfer-tube insertion hole and the corresponding second-refrigerant heat-transfer tube are joined together by being fixed by the brazing material flowed into a space between the second-refrigerant heat-transfer tube and the second-refrigerant heat-transfer-tube insertion hole by melting.   
     
     
         25 . The heat exchanger of  claim 21 , wherein
 the first-refrigerant passage group is one of a plurality of first-refrigerant passage groups and the first-refrigerant passage groups are disposed adjacent to each other, and   the first-refrigerant communicating holes are in communication with all of the first-refrigerant passages included in the plurality of the first-refrigerant passage groups.   
     
     
         26 . The heat exchanger of  claim 21 , wherein
 the second-refrigerant passage group is one of the plurality of second-refrigerant passage groups and the second-refrigerant passage groups are disposed adjacent to each other, and   the second-refrigerant communicating portions are in communication with all of the second-refrigerant passages included in the plurality of the second-refrigerant passage groups.   
     
     
         27 . The heat exchanger of  claim 21 , wherein
 the first-refrigerant passage group and the second-refrigerant passage group are one of a plurality of first-refrigerant passage groups and a plurality of second-refrigerant passage groups,   the first-refrigerant passage groups and the second-refrigerant passage groups are alternately arranged and adjacent to each other,   the first-refrigerant communicating holes are formed at the both ends of each group of the first-refrigerant passage groups in the refrigerant flow direction,   the second-refrigerant communicating portions are formed at the both ends of each group of the second-refrigerant passage groups in the refrigerant flow direction,   first collecting portions are formed in a column direction of the plurality of the first-refrigerant communicating holes that are disposed parallel at the same end of the refrigerant flow direction of the first-refrigerant passage groups, each of the first collecting portions being in communication with the plurality of the first-refrigerant communicating holes, and second collecting portions are formed in a column direction of the plurality of the second-refrigerant communicating portions that are disposed parallel at the same end of the refrigerant flow direction of the second-refrigerant communicating portions, each of the second collecting portions being in communication with the plurality of the second-refrigerant communicating portions,   the first refrigerant flows in and flows out of the first collecting portion and flows through the first-refrigerant communicating holes and the first-refrigerant passage groups, and   the second refrigerant flows in and flows out of the second collecting portion and flows through the second-refrigerant communicating portions and the second-refrigerant passage groups.   
     
     
         28 . The heat exchanger of  claim 27 , wherein
 the first-refrigerant passage group and the second-refrigerant passage group that are arranged adjacent to each other are configured as a single module, and   a plurality of the modules are stacked and joined to one another.   
     
     
         29 . The heat exchanger of  claim 27 , wherein
 at least one of the first collecting portions that are formed at the both ends of the first-refrigerant passage groups in the refrigerant flow direction is divided into a plurality of portions,   the first collecting portions include
 a first-refrigerant dividing-and-collecting-portion inflow portion that allows the first refrigerant to flow in from an outside and allows the first refrigerant to flow through one or some of the plurality of the first-refrigerant communicating holes and through the first-refrigerant passage groups that are in communication with the one or some of the plurality of the first-refrigerant communicating holes, 
 one or more first-refrigerant dividing-and-collecting-portion turn-back portions that allow the first refrigerant that has passed through part of the first-refrigerant passage groups and the first-refrigerant communicating holes that are in communication with the part of the first-refrigerant passage groups to flow back through a portion of the first-refrigerant communicating holes other than the one or some of the first-refrigerant communicating holes and through the first-refrigerant passage groups that are in communication with the portion of the first-refrigerant communicating holes other than the one or some of the first-refrigerant communicating holes, and 
 a first-refrigerant dividing-and-collecting-portion outflow portion that allows the first refrigerant that has flowed from the one or more first-refrigerant dividing-and-collecting-portion turn-back portions through the portion of the first-refrigerant communicating holes and through the first-refrigerant passage groups that are in communication with the portion of the first-refrigerant communicating holes to flow out to the outside, and 
   the first refrigerant flows so as to flow back through the first-refrigerant passage groups.   
     
     
         30 . The heat exchanger of  claim 27 , wherein
 at least one of the second collecting portions that are formed at the both ends of the second-refrigerant passage groups in the refrigerant flow direction is divided into a plurality of portions,   the second collecting portions include
 a second-refrigerant dividing-and-collecting-portion inflow portion that allows the second refrigerant to flow in from the outside and allows the second refrigerant to flow through one or some of the plurality of the second-refrigerant communicating portions and through the second-refrigerant passage groups that are in communication with the one or some of the plurality of the second-refrigerant communicating portions, 
 one or more second-refrigerant dividing-and-collecting-portion turn-back portions that allow the second refrigerant that has passed through part of the second-refrigerant passage groups and the second-refrigerant communicating portions that are in communication with the part of the second-refrigerant passage groups to flow back through a portion of the second-refrigerant communicating portions other than the one or some of the second-refrigerant communicating portions and through the second-refrigerant passage groups that are in communication with the portion of the second-refrigerant communicating portions other than the one or some of the second-refrigerant communicating portions, and 
 a second-refrigerant dividing-and-collecting-portion outflow portion that allows the second refrigerant that has flowed from the one or more second-refrigerant dividing-and-collecting-portion turn-back portions through the portion of the second-refrigerant communicating portions and through the second-refrigerant passage groups that are in communication with the portion of the second-refrigerant communicating portions to flow out to the outside, and 
   the second refrigerant flows so as to flow back through the second-refrigerant passage groups.   
     
     
         31 . The heat exchanger of  claim 21 , wherein
 at least one of the first-refrigerant communicating holes that are formed at the both ends of the first-refrigerant passage group in the refrigerant flow direction is divided into a plurality of portions,   the first-refrigerant communicating holes include
 a first-refrigerant dividing-and-communicating-hole inflow portion that allows the first refrigerant to flow in from the outside and allows the first refrigerant to flow through one or some of the plurality of the first-refrigerant passages, 
 one or more first-refrigerant dividing-and-communicating-hole turn-back portions that allows the first refrigerant that has passed through the one or some of the first-refrigerant passages to flow back through a portion of the first refrigerant passages other than the one or some of the first refrigerant passages, and 
 a first-refrigerant dividing-and-communicating-hole outflow portion that allows the first refrigerant that has flowed from the one or more first-refrigerant dividing-and-communicating-hole turn-back portions and passed through the portion of the first-refrigerant passages to flow to the outside, and 
   the first refrigerant flows so as to flow back through the first-refrigerant passages of the first-refrigerant passage group.   
     
     
         32 . The heat exchanger of  claim 21 , wherein
 at least one of the second-refrigerant communicating portions that are formed at the both ends of the second-refrigerant passage group in the refrigerant flow direction is divided into a plurality of portions,   the second-refrigerant communicating portions include
 a second-refrigerant dividing-and-communicating-portion inflow portion that allows the second refrigerant to flow in from the outside and allows the second refrigerant to flow through one or some of the plurality of the second-refrigerant passages, 
 one or more second-refrigerant dividing-and-communicating-portion turn-back portions that allow the second refrigerant that has passed through the one or some of the second-refrigerant passages to flow back through a portion of the second refrigerant passages other than the one or some of the second refrigerant passages, and 
 a second-refrigerant dividing-and-communicating-portion outflow portion that allows the second refrigerant that has flowed from the one or more second-refrigerant dividing-and-communicating-portion turn-back portions and passed through the portion of the second-refrigerant passages to flow to the outside, and 
   the second refrigerant flows so as to flow back through the second-refrigerant passages of the second-refrigerant passage group.   
     
     
         33 . The heat exchanger of  claim 21 , wherein the first refrigerant and the second refrigerant flow counter to each other in at least a portion of the refrigerant passages. 
     
     
         34 . A refrigeration cycle apparatus including the heat exchanger of  claim 21 .