Patent Publication Number: US-11391521-B2

Title: Heat exchanger, heat exchanger unit, and refrigeration cycle apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a U.S. national stage application of PCT/JP2018/022576 filed on Jun. 13, 2018, the contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a heat exchanger, a heat exchanger unit provided with the heat exchanger, and a refrigeration cycle apparatus, and particularly to a structure of a spacer that maintains an interval between fins installed on heat transfer tubes. 
     BACKGROUND ART 
     Some heat exchanger has been known that is provided with flat tubes, to improve heat exchange performance, that are each a heat transfer tube having a flat sectional shape with multiple holes. One example of such a heat exchanger is a heat exchanger where flat tubes are arranged at predetermined intervals from one another in the up-and-down direction with the direction of pipe axes extending in the lateral direction. In such a heat exchanger, plate-like fins are aligned in the direction of the pipe axes of the flat tubes, and heat is exchanged between air passing through between the fins and fluid flowing through the flat tubes. 
     Some fin has been known that is provided with a fin collar at the peripheral edge of a flat tube insertion portion. The fin collar ensures a separation between the fins by causing the distal end of the fin collar to be in contact with the next fin. In recent years, as the thickness of the flat tube has been reduced, the width of the flat tube insertion portion of the fin is small and hence, it is difficult to raise the fin collar, which is provided to the peripheral edge of the flat tube insertion portion, up to a predetermined height. To solve the problem, in Patent Literature 1, spacers are provided to each fin to maintain intervals between fins disposed next to each other, and each spacer is formed by bending a portion of the fin at a portion other than the peripheral edge of the flat tube insertion portion. The fin has an insertion region where the flat tube is inserted, and an extension region formed downwind of the insertion region. The spacers are formed in the insertion region and the extension region. The spacer in the extension region is formed right behind the spacer in the insertion region (see Patent Literature 1, for example). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent No. 5177307 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the heat exchanger disclosed in Patent Literature 1, the spacer is formed by bending a portion of the fin, and the spacer is provided with a surface of the spacer directed in a direction of the flow of air passing through between the fins. A problem is consequently caused in that the area of an air passage between the fins decreases, so that ventilation properties of the heat exchanger are deteriorated. Further, in the case where the spacer is provided with the surface of the spacer extending along the direction of the flow of air, a problem lies in that, on the surface of the spacer, frost forms and stagnates and meltwater of frost stagnates, so that drainage properties and defrosting properties of the heat exchanger are reduced. Further, in the heat exchanger disclosed in Patent Literature 1, the flat tubes are disposed with the longitudinal direction of the sectional shape of each flat tube extending in the horizontal direction and hence, a problem lies in that water stagnates on the flat tube, and is not easily drained. 
     The present disclosure has been made to solve the above-mentioned problems, and it is an object of the present disclosure to provide a heat exchanger, a heat exchanger unit, and a refrigeration cycle apparatus where a reduction of drainage properties and ventilation properties is prevented, and an air passage is not easily clogged when frost forms. 
     Solution to Problem 
     A heat exchanger according to one embodiment of the present disclosure includes a flat tube and a plurality of fins that are each a plate having a plate surface extending in a longitudinal direction and in a width direction orthogonal to the longitudinal direction. The plate surface intersects a pipe axis of the flat tube, and the plurality of fins are arranged at an interval from one another. The plurality of fins each have a first spacer formed in the plate and maintaining the interval. The flat tube has a longitudinal axis of a section perpendicular to the pipe axis, and the longitudinal axis is inclined to the width direction by an inclination angle θ. The first spacer has a standing surface extending in a direction intersecting the plate surface, and the standing surface is inclined in a direction same as that of the inclination angle θ. 
     A heat exchanger unit according to another embodiment of the present disclosure includes the above-mentioned heat exchanger, and a fan configured to send air to the heat exchanger. 
     A refrigeration cycle apparatus according to still another embodiment of the present disclosure includes the above-mentioned heat exchanger unit. Advantageous Effects of Invention 
     According to an embodiment of the present disclosure, with the above-mentioned configuration, the spacer appropriately maintains the interval between the fins. It is therefore possible to prevent the clogging of the air passage when frost forms, and drainage properties of meltwater are ensured during the defrosting process. Further, the spacer is inclined in the same direction as the flat tube, so that it is possible to prevent the blockage of the flow of air along the flat tube, and the reduction of ventilation properties between the fin and the flat tube. Resistance against frost and drainage properties of the heat exchanger, the heat exchanger unit, and the refrigeration cycle apparatus are therefore enhanced while heat exchange performance is maintained. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a heat exchanger according to Embodiment 1. 
         FIG. 2  is an explanatory view of a refrigeration cycle apparatus to which the heat exchanger according to Embodiment 1 is applied. 
         FIG. 3  is an explanatory view of the sectional structure of the heat exchanger shown in  FIG. 1 . 
         FIG. 4  includes enlarged views of a spacer provided to fins of the heat exchanger according to Embodiment 1. 
         FIG. 5  is an explanatory view of a spacer that is a comparative example of the spacer formed on the fins of the heat exchanger according to Embodiment 1. 
         FIG. 6  includes explanatory views of a spacer that is a modification of the spacer formed on the fins of the heat exchanger according to Embodiment 1. 
         FIG. 7  includes explanatory views of a spacer that is a modification of the spacer formed on the fins of the heat exchanger according to Embodiment 1. 
         FIG. 8  is an explanatory view of the sectional structure of a heat exchanger that is a comparative example of the fin of the heat exchanger according to Embodiment 1. 
         FIG. 9  is an explanatory view of the sectional structure of a heat exchanger that is a modification of the heat exchanger according to Embodiment 1. 
         FIG. 10  is an explanatory view of the sectional structure of a heat exchanger that is a modification of the heat exchanger according to Embodiment 1. 
         FIG. 11  is an explanatory view of the sectional structure of a heat exchanger that is a modification of the heat exchanger according to Embodiment 1. 
         FIG. 12  is an explanatory view of the flow of air passing through the heat exchanger according to Embodiment 1. 
         FIG. 13  is an explanatory view of the sectional structure of a heat exchanger according to Embodiment 2. 
         FIG. 14  is an explanatory view of the sectional structure of a heat exchanger according to Embodiment 3. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of a heat exchanger, a heat exchanger unit, and a refrigeration cycle apparatus are described. Hereinafter, the embodiments of the present disclosure are described with reference to drawings. In the drawings, components and portions given the same reference signs are the same or corresponding components and portions, and the reference signs are common in the entire specification. Further, forms of components described in the entire specification are merely examples, and the present disclosure is not limited to the description in the specification. In particular, the combination of the components is not limited to the combination in each embodiment, and components described in one embodiment may be applicable to another embodiment. Further, when it is not necessary to distinguish or specify a plurality of components or portions of the same kind that are, for example, differentiated by suffixes, the suffixes may be omitted. In the drawings, the relationship in size of the components and portions may differ from that of actual components and portions. It is noted that directions indicated by “x”, “y”, and “z” in the drawings indicate the same directions in the drawings. 
     Embodiment 1 
       FIG. 1  is a perspective view showing a heat exchanger  100  according to Embodiment 1.  FIG. 2  is an explanatory view of a refrigeration cycle apparatus  1  to which the heat exchanger  100  according to Embodiment 1 is applied. The heat exchanger  100  shown in  FIG. 1  is a heat exchanger to be mounted on the refrigeration cycle apparatus  1 , such as an air-conditioning apparatus and a refrigerator. In Embodiment 1, an air-conditioning apparatus is described as an example of the refrigeration cycle apparatus  1 . The refrigeration cycle apparatus  1  has a configuration in which a compressor  3 , a four-way valve  4 , an outdoor heat exchanger  5 , an expansion device  6 , and an indoor heat exchanger  7  are connected by a refrigerant pipe  90  to form a refrigerant circuit. In the refrigeration cycle apparatus  1 , refrigerant flows through the refrigerant pipe  90 . By switching the flows of the refrigerant by the four-way valve  4 , the operation of the refrigeration cycle apparatus  1  is switched to one of a heating operation, a refrigerating operation, and a defrosting operation. 
     The outdoor heat exchanger  5  is mounted on an outdoor unit  8 , the indoor heat exchanger  7  is mounted on an indoor unit  9 , and a fan  2  is disposed in the vicinity of each of the outdoor heat exchanger  5  and the indoor heat exchanger  7 . In the outdoor unit  8 , the fan  2  sends outside air into the outdoor heat exchanger  5  to exchange heat between the outside air and refrigerant. In the indoor unit  9 , the fan  2  sends indoor air into the indoor heat exchanger  7  to exchange heat between the indoor air and refrigerant, so that the temperature of the indoor air is conditioned. Further, in the refrigeration cycle apparatus  1 , the heat exchanger  100  may be used as the outdoor heat exchanger  5 , mounted on the outdoor unit  8 , or as the indoor heat exchanger  7 , mounted on the indoor unit  9 , and the heat exchanger  100  is used as a condenser or an evaporator. In the specification, a unit, such as the outdoor unit  8  and the indoor unit  9 , on which the heat exchanger  100  is mounted is particularly referred to as “heat exchanger unit”. 
     The heat exchanger  100  shown in  FIG. 1  includes two heat exchange parts  10 ,  20 . The heat exchange parts  10 ,  20  are arranged in series along the x direction shown in  FIG. 1 . The x direction is a direction perpendicular to a direction along which flat tubes  30  of the heat exchange part  10  are arranged in parallel and to a direction along which the pipe axes of the flat tubes  30  extend. In Embodiment 1, air flows into the heat exchanger  100  along the x direction. The heat exchange parts  10 ,  20  are consequently arranged in series along a direction along which air flows through the heat exchanger  100 . The first heat exchange part  10  is disposed upwind, and the second heat exchange part  20  is disposed downwind. Headers  60 ,  61  are disposed at both ends of the heat exchange part  10 , and the header  60  and the header  61  are connected with each other by the flat tubes  30 . The header  60  and a header  62  are disposed at both ends of the heat exchange part  20 , and the header  60  and the header  62  are connected with each other by the flat tubes  30 . Refrigerant flowing into the header  61  from a refrigerant pipe  91  passes through the heat exchange part  10 , flows into the heat exchange part  20  through the header  60 , and flows out to a refrigerant pipe  92  from the header  62 . The heat exchange part  10  and the heat exchange part  20  may have the same structure, or may have different structures. 
       FIG. 3  is an explanatory view of the sectional structure of the heat exchanger  100  shown in  FIG. 1 .  FIG. 3  is an explanatory view showing a portion of a section A of the heat exchange part  10  of the heat exchanger  100  shown in  FIG. 1  as the portion is viewed from the lateral direction, and the section A is perpendicular to the y axis. The heat exchange part  10  has a configuration in which the plurality of flat tubes  30  are arranged in parallel in the z direction with the pipe axes of the flat tubes  30  extending in the y direction. Refrigerant flows through the flat tubes  30 , so that heat is exchanged between air sent into the heat exchanger  100  and the refrigerant flowing through the flat tubes  30 . Further, the heat exchange part  10  has a configuration in which fins  40  are attached to the flat tubes  30  with a plate surface  48  of each fin  40 , which is a plate, intersecting the pipe axes of the flat tubes  30 . The fin  40  has a rectangular shape having the longitudinal direction of the fin  40  extending in a direction along which the flat tubes  30  are arranged in parallel. In other words, the fin  40  is provided with the longitudinal direction of the fin  40  extending along the z direction. A first end edge  41 , which is one end edge in the x direction, of the fin  40  is positioned upwind, and a second end edge  42 , which is the other end edge, of the fin  40  is positioned downwind. Cut-out portions  44  are formed at the second end edge  42 . The flat tubes  30  are fitted in these cut-out portions  44 . The width direction of the fin  40  means a direction orthogonal to the longitudinal direction of the fin  40 , and aligns with the x direction. In  FIG. 3 , two flat tubes  30  are shown. These two flat tubes  30  disposed next to each other along the longitudinal direction of the fin  40  may be referred to as “first flat tube” and “second flat tube”. 
     Each flat tube  30  has the longitudinal axis of a section inclined to the width direction of the fin  40  by an inclination angle θ. A first end portion  31  positioned closer to the first end edge  41  of the fin  40  than is a second end portion  32  is positioned lower than is the second end portion  32  positioned closer to the second end edge  42  than is the first end portion  31 . Each cut-out portion  44  formed at the second end edge  42  of the fin  40  is also inclined to the width direction of the fin  40  by the inclination angle θ. 
     The plurality of fins  40  are arranged along a direction along which the pipe axes of the flat tubes  30  extend. The fins  40  disposed next to each other are disposed with a predetermined gap between the fins  40  so that air is allowed to pass through between the fins  40 . To ensure an interval between the fins  40  disposed next to each other, a first spacer  50   a  and a second spacer  50   b  are formed on the fins  40 . Hereinafter, the first spacer  50   a  and the second spacer  50   b  may be collectively referred to as “spacer  50 ”. The spacer  50  is formed by bending a portion of the fin  40 , which is a plate, and the spacer  50  is erected in a direction intersecting the plate surface  48 . 
       FIG. 4  includes enlarged views of the spacer  50  provided to the fins  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 4( a )  is an enlarged view as the spacer  50  is viewed from the direction illustrated by an arrow C in  FIG. 3 , and is an enlarged view as the spacer  50  is viewed from a direction parallel to the plate surfaces  48  of the fins  40  and parallel to a standing surface  53  of the spacer  50 .  FIG. 4( b )  is an explanatory view of the structure of the spacer  50  as the spacer  50  is viewed from a direction perpendicular to a section taken along B-B in  FIG. 4( a ) . The spacer  50  is erected toward the next fin  40 , and the distal end of the spacer  50  is in contact with the plate surface  48  of the next fin  40 . The distal end of the spacer  50  is bent to form a contact portion  52 . In Embodiment 1, the standing surface  53  of the spacer  50  extends substantially perpendicular to the plate surface  48  of the fin  40 . The spacer  50  is formed by bending a portion of the fin  40  in a direction intersecting the plate surface  48 . An opening port  51  is formed adjacent to the spacer  50  in the opposite direction of the z direction. An opening port  51   a  adjacent to the first spacer  50   a  may be referred to as “first opening port”, and an opening port  51   b  adjacent to the second spacer  50   b  may be referred to as “second opening port”. Further, a standing surface  53   a  of the first spacer  50   a  may be referred to as “first standing surface”, and a standing surface  53   b  of the second spacer  50   b  may be referred to as “second standing surface”. 
       FIG. 5  is an explanatory view of a spacer  150   c  that is a comparative example of the spacer  50  formed on the fins  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 5  is an explanatory view as the spacer  150   c  is viewed in the same direction as  FIG. 4( b ) . The spacer  150   c  of the comparative example is formed by bending a portion of a fin  140  in the opposite direction of the z direction in  FIG. 5 . In other words, when the heat exchanger  100  is installed with the opposite direction of the z direction in  FIG. 5  aligning with the direction of gravity, the spacer  150   c  is formed by bending the portion of the fin  140  in the direction of gravity. A standing surface  153   c  is formed substantially perpendicular to the plate surface  48 . In this case, an opening port  151   c  is formed over the spacer  150   c . When condensation water or meltwater of frost flows down to the spacer  150   c , not only water stays on the standing surface  153   c , but also water adheres to the edge of the opening port  151   c  because of capillarity. Further, water drops also adhere to a portion under the spacer  150   c  in such a manner that the water drops hang from the portion under the spacer  150   c , so that the spacer  150   c  and the opening port  151   c  maintain water in a region surrounded by a dotted line  180  in  FIG. 5 . In contrast, water drops adhere to the spacer  50  and the opening port  51  according to Embodiment 1 in such a manner that the water drops hang from a portion under the spacer  50  as shown by a dotted line  80  in  FIG. 4( b ) . The amount of water maintained at the spacer  50  and the opening port  51  is consequently small compared with that maintained at the spacer  150   c  and the opening port  151   c  of the comparative example. In other words, the spacer  50  and the opening port  51  according to Embodiment 1 maintains less amount of water and has higher drainage properties compared with the spacer  150   c  and the opening port  151   c  of the comparative example. 
     As shown in  FIG. 3 , in Embodiment 1, the spacer  50  is provided at two positions between two flat tubes  30  arranged in the longitudinal direction of the fin  40 . The spacers  50  are aligned in the width direction of the fin  40 , and are disposed in such a manner that a stable interval between the fins  40  is ensured. The first spacer  50   a  is disposed close to the first end edge  41  of the fin  40 , and is positioned on a first imaginary line L 1  connecting lower ends of the first end portions  31  of the flat tubes  30  aligned in the up-and-down direction. 
     When the fin  40  is viewed in the y direction, that is, when the fin  40  is viewed in a direction perpendicular to the plate surface  48 , the standing surface  53   a  of the first spacer  50   a  is inclined in the direction same as that of the inclination angle θ of the flat tube  30 , and the standing surface  53   a  is inclined by an inclination angle α 1 . Each of the inclination angle θ and the inclination angle α 1  is an angle by which the flat tube  30  or the standing surface  53   a  is inclined to the x axis on a section perpendicular to the pipe axes of the flat tubes  30  and, in other words, is an angle by which the flat tube  30  or the standing surface  53   a  is inclined to a straight line horizontal to the width direction of the fin  40 . The inclination angle α 1  of the standing surface  53   a  of the first spacer  50   a  is set to satisfy a mathematical formula of 0&lt;α 1 ≤θ. 
     The second spacer  50   b  is formed on the fin  40  in an intermediate region  43 , which is a region between the cut-out portions  44  into which the flat tubes  30  are inserted. The standing surface  53   b  of the second spacer  50   b  is also inclined in the same direction as the direction in which the flat tube  30  is inclined in the same manner as the standing surface  53   b  of the first spacer  50   a . The second spacer  50   b  has an inclination angle α 2 , and is set to satisfy a mathematical formula of 0&lt;α 2 ≤θ. The inclination angle α 2  is also an angle by which the standing surface  53   b  is inclined to the x axis on the section perpendicular to the pipe axes of the flat tubes  30  and, in other words, is an angle by which the standing surface  53   b  is inclined to a straight line horizontal to the width direction of the fin  40 . 
     Modification of Spacer  50   
       FIG. 6  includes explanatory views of a spacer  150   a  that is a modification of the spacer  50  formed on the fins  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 6( a )  corresponds to  FIG. 4( a ) , and  FIG. 6( b )  corresponds to  FIG. 4( b ) . Each of the first spacer  50   a  and the second spacer  50   b  provided to the fins  40  of the heat exchanger  100  according to Embodiment 1 may have the structure of the spacer  150   a  as shown in  FIG. 6 , for example. The spacer  150   a  is formed in such a manner that two slits are formed in a plate surface  148   a  of the fin  140 , and a portion between these slits is caused to protrude from the plate surface  148   a . The spacer  150   a  is consequently connected with the plate surface  148   a  at two positions. In  FIG. 6 , an upper surface of the spacer  150   a  is a standing surface  153   a . In the same manner as the standing surface  53  of the spacer  50 , the standing surface  153   a  is inclined in the same direction as the flat tube  30  in the heat exchanger  100  when the standing surface  153   a  is viewed in they direction. 
       FIG. 7  includes explanatory views of a spacer  150   b  that is a modification of the spacer  50  formed on the fins  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 7( a )  corresponds to  FIG. 4( a ) , and  FIG. 7( b )  corresponds to  FIG. 4( b ) . The spacer  150   b  is formed in such a manner that the spacer  150   b  is caused to protrude from a plate surface  148   b  of the fin  140  in a rectangular shape. In  FIG. 7 , an upper surface of the spacer  150   b  is a standing surface  153   b . In the same manner as the standing surface  53  of the spacer  50 , the standing surface  153   b  is inclined in the same direction as the flat tube  30  in the heat exchanger  100  when the standing surface  153   b  is viewed from they direction. 
     Draining Action of Heat Exchanger  100   
     Advantageous effects of the heat exchanger  100  according to Embodiment 1 are described below. To facilitate understanding of drainage properties of the heat exchanger  100  according to Embodiment 1, hereinafter, the description is made for the operation of the heat exchanger  100  when the heat exchanger  100  is operated as an evaporator under the condition that outside air has a low temperature. Subsequently, the configuration of a heat exchanger  1100  of a comparative example is described, and the draining action of the heat exchanger  100  according to Embodiment 1 is then described. 
       FIG. 8  is an explanatory view of the sectional structure of the heat exchanger  1100  that is the comparative example of the fin  40  of the heat exchanger  100  according to Embodiment 1. In the same manner as  FIG. 3 ,  FIG. 8  shows a section perpendicular to the pipe axes of the flat tubes  30 . Also in a fin  1040  of the heat exchanger  1100  of the comparative example, spacers  1050   a ,  1050   b  are formed in a region between the flat tubes  30 . Each of the spacers  1050   a ,  1050   b  is formed by bending a portion of the fin  1040 , and standing surfaces  1053   a ,  1053   b  are formed to be horizontal to the width direction of the fin  1040 . Further, opening ports  1051   a ,  1051   b  are respectively formed below and adjacently to the spacers  1050   a ,  1050   b.    
     During the operation of the refrigeration cycle apparatus  1 , condensation water or meltwater of frost flows down onto the fin  1040  from above. In such a case, water flows down also onto the standing surfaces  1053   a ,  1053   b  of the spacers  1050   a ,  1050   b . In the heat exchanger  1100  of the comparative example, the spacers  1050   a ,  1050   b  are formed to be horizontal, so that water stagnates on the standing surfaces  1053   a ,  1053   b , and is not drained. Water on the standing surfaces  1053   a ,  1053   b  is consequently frozen, and a frozen portion expands using the frozen water as a base point and thus becomes a cause of clogging of an air passage, or breakage of the heat exchanger  1100 . 
     In contrast, in the heat exchanger  100  according to Embodiment 1, the first spacer  50   a  and the second spacer  50   b  are inclined, so that water on the standing surfaces  53   a ,  53   b  is rapidly drained by gravity and flows downward. With such a configuration, in the heat exchanger  100 , an appropriate gap is ensured between the fins  40  disposed next to each other, and water flowing down onto the standing surface  53  of the first spacer  50   a  does not stagnate. The heat exchanger  100  consequently has high drainage properties, and has no clogging of an air passage between the fins  40  and hence, no possibility remains that heat exchange performance of the heat exchanger  100  is impaired. 
     To prevent ventilation resistance in the heat exchanger  100 , and to reduce the amount of refrigerant filled in the refrigeration cycle apparatus  1  for lessening an effect on global warming, the transverse axis of the flat tube  30  is set to have a small value, that is, the thickness of the flat tube  30  is reduced. With such a reduction in thickness, in providing a fin collar to the peripheral edge of the cut-out portion  44  for appropriately ensuring intervals between the fins  40 , the cut-out portion  44  into which the fin  40  is to be inserted has a small width and hence, it is difficult to raise the fin collar, which is provided to the peripheral edge of the cut-out portion  44 , up to a predetermined height. However, by providing the spacer  50  to the fin  40  as in the case of the heat exchanger  100  according to Embodiment 1, it is possible to appropriately ensure intervals between the fins  40 . 
     Modification of First Spacer 
       FIG. 9  is an explanatory view of the sectional structure of a heat exchanger  100   a  that is a modification of the heat exchanger  100  according to Embodiment 1. In the heat exchanger  100   a  of the modification, the first spacer  50   a  is disposed in a region close to the first end edge  41  of the fin  40 , and no cut-out portion  44  is provided at the first end edge  41 . In other words, the first spacer  50   a , disposed close to the first end edge  41  of the fin  40 , is disposed in such a manner that the first spacer  50   a  at least does not overlap with the first imaginary line L 1  connecting the first end portions  31  of the flat tubes  30  aligned in the z direction. 
     In the heat exchanger  100   a  of the modification, the first spacer  50   a  is disposed away from the first imaginary line L 1  by 1 mm or more, for example. By disposing the first spacer  50   a  as described above, when water on the flat tube  30  flows down from the first end portion  31  of the flat tube  30 , water flows through a drainage region h formed between the first spacer  50   a  and the first end portions  31  of the flat tubes  30 . In the case where the direction of gravity aligns with the longitudinal direction of the fin  40 , no object that blocks the flow of water is disposed in the drainage region h and hence, the heat exchanger  100   a  of the modification has further improved drainage properties compared with the heat exchanger  100 . 
       FIG. 10  is an explanatory view of the sectional structure of a heat exchanger  100   b  that is a modification of the heat exchanger  100  according to Embodiment 1. In the heat exchanger  100   b  of the modification, the first spacer  50   a  is disposed in the intermediate region  43  of the fin  40 , and the intermediate region  43  is disposed between two cut-out portions  44  disposed next to each other. In other words, the first spacer  50   a , disposed close to the first end edge  41  of the fin  40 , is disposed in the intermediate region  43  in such a manner that the first spacer  50   a  does not overlap with the first imaginary line L 1  connecting the first end portions  31  of the flat tubes  30  aligned in the z direction in  FIG. 10 . 
     In the heat exchanger  100   b  of the modification, the first spacer  50   a  is not disposed in the region close to the first end edge  41  of the fin  40 , and no cut-out portion  44  is provided at the first end edge  41 . No possibility consequently remains that the first spacer  50   a  blocks the flow of water from above shown in  FIG. 10 . Further, when water staying on an upper surface  33  of the flat tube  30  flows down from the first end portion  31  of the flat tube  30 , the water flows through the drainage region h positioned closer to the first end edge  41  than the first end portion  31  of the flat tube  30 . In the case where the direction of gravity aligns with the longitudinal direction of the fin  40 , that is, the direction of gravity aligns with the z direction in  FIG. 10 , no object that blocks the flow of water is disposed in the drainage region h and hence, the heat exchanger  100   b  of the modification has further improved drainage properties compared with the heat exchanger  100 . 
       FIG. 11  is an explanatory view of the sectional structure of a heat exchanger  100   c  that is a modification of the heat exchanger  100  according to Embodiment 1. The heat exchanger  100   c  of the modification is obtained by causing the fin  40  to extend farther in the downwind direction than the second end portions  32  of the flat tubes  30 . As the shape of the fin  40  is caused to extend in the downwind direction, the cut-out portions  44  are also formed to extend in the downwind direction. Nothing is disposed in a region of the cut-out portion  44  at a portion close to the second end edge  42 . In the heat exchanger  100  according to Embodiment 1, the second end edge  42  and the second end portions  32  of the flat tubes  30  are disposed at substantially the same position in the x direction. In contrast, in the heat exchanger  100   c  of the modification, the second end edge  42  of the fin  40  is positioned away from the second end portions  32  of the flat tubes  30  in the x direction. Further, in the intermediate region  43 , the second spacer  50   b  is disposed in a region between the second end portions  32  and the second end edge  42  of the fin  40 , and each second end portion  32  is the end portion of the flat tube  30  disposed downwind in the width direction of the fin  40 . By disposing the second spacer  50   b  further downstream than is the flat tube  30 , it is possible to prevent the reduction of heat exchange performance of the heat exchanger  100   c  caused by the provision of the second spacer  50   b.    
     In the heat exchanger  100 ,  100   a ,  100   b ,  100   c  according to Embodiment 1, the second spacer  50   b  is formed in the intermediate region  43  of the fin  40 . However, as long as intervals between the fins  40  are appropriately ensured, the second spacer  50   b  may not be provided. Further, it is not always necessary to provide the spacer  50  in every space provided between the flat tubes  30 , and the positions where spacers  50  are installed may be suitably changed. In addition to the above, it is not always necessary to provide the first spacer  50   a  and the second spacer  50   b  as a set, and only either one of the first spacer  50   a  or the second spacer  50   b  may be provided at some positions. 
     Ventilation Properties of Heat Exchanger  100   
       FIG. 12  is an explanatory view of the flow of air passing through the heat exchanger  100  according to Embodiment 1.  FIG. 12  shows a state where the first end edge  41  of the fin  40  of the heat exchanger  100  is disposed upwind. In the heat exchanger  100 , the first spacer  50   a  and the second spacer  50   b  are provided, so that intervals between the fins  40  are appropriately maintained. Air consequently passes through between the fins  40  and the flat tubes  30 , so that heat is exchanged between the air and fluid flowing through the flat tubes  30 . Each flat tube  30  is inclined to the direction of the flow of air flowing into the heat exchanger  100  and hence, the air that enters the heat exchanger  100  comes into contact with the upper surface  33  of the flat tube  30 , so that the direction of the flow changes. 
     The first spacer  50   a  and the second spacer  50   b  are provided between the fins  40  of the heat exchanger  100 . The standing surface  53   a  of the first spacer  50   a  and the standing surface  53   b  of the second spacer  50   b  are inclined in a direction same as that of the inclination angle θ of the flat tube  30  and hence, the flow of air is not easily blocked. Further, the inclination angle α 1  of the standing surface  53   a  of the first spacer  50   a  is smaller than the inclination angle θ of the flat tube  30 , so that the direction of the flow of air is gently changed and hence, no possibility remains that ventilation properties are impaired. Further, the inclination angle α 2  of the standing surface  53   b  of the second spacer  50   b  is set to a value close to the value of the inclination angle θ of the flat tube  30 , so that the flow of air is not blocked in the intermediate region  43  between the flat tubes  30  disposed next to each other. 
     In the heat exchanger  100   a  of the modification shown in  FIG. 9 , the first spacer  50   a  is positioned upwind of the flat tube  30 . By setting the inclination angle α 1  to a small value, ventilation properties are consequently not impaired. In the heat exchanger  100   b  of the modification shown in  FIG. 10 , the first spacer  50   a  is positioned in the intermediate region  43 , and is thus positioned downwind of the first end portion  31  of the flat tube  30 . It is consequently preferable to set the inclination angle α 1  to a value close to the value of the inclination angle θ of the flat tube  30 . 
     The description has been made above for a state where air flows into the heat exchanger  100  from a direction perpendicular to the first end edge  41  of the fin  40  of the heat exchanger  100 . However, there may be also a case where the heat exchanger  100  is disposed and inclined to the direction of gravity, for example. The inclination angle of each of the flat tubes  30 , the first spacer  50   a , and the second spacer  50   b  is only required to be suitably set corresponding to an environment where the heat exchanger  100  is disposed. 
     Advantageous Effects of Embodiment 1 
     In the heat exchanger  100 ,  100   a ,  100   b  according to Embodiment 1, the first spacer  50   a  is inclined in the same direction as the flat tube  30  and hence, it is possible to prevent stagnation, on the first spacer  50   a , of water flowing from an upper portion of the fin  40 . Further, the inclination angle α 1  of the standing surface  53   a  of the first spacer  50   a  has the relationship of the mathematical formula of 0&lt;α 1 ≤θ, so that the flow of air flowing into the heat exchanger  100 ,  100   a ,  100   b  is not easily blocked. Resistance against frost and drainage properties of the heat exchanger  100 ,  100   a ,  100   b  are consequently enhanced while heat exchange performance is maintained. Further, even in the case where the transverse axis of the flat tube  30  is shorter than the interval between the arranged fins  40 , it is also possible to appropriately ensure a gap between the fins  40  by the first spacer  50   a.    
     Embodiment 2 
     A heat exchanger  200  according to Embodiment 2 is a heat exchanger obtained by changing the disposition of the first spacer  50   a  from that in the heat exchanger  100  according to Embodiment 1. The description of the heat exchanger  200  according to Embodiment 2 is made below mainly for points different from Embodiment 1. In the drawings, portions of the heat exchanger  200  according to Embodiment 2 having the same functions as those in Embodiment 1 are given the same reference signs as used in the drawings for describing Embodiment 1. 
       FIG. 13  is an explanatory view of the sectional structure of the heat exchanger  200  according to Embodiment 2.  FIG. 13  shows a section perpendicular to the pipe axes of the flat tubes  30  shown in  FIG. 1 . A first spacer  250   a  is provided to a fin  240  of the heat exchanger  200  and positioned close to a first end edge  241 . The first spacer  250   a  is disposed and positioned closer to the first end edge  41  than the first imaginary line L 1  connecting the first end portions  31  of the flat tubes  30  aligned in the up-and-down direction. Further, the first spacer  250   a  is positioned between an imaginary line La and an imaginary line Lb. The imaginary line La extends in the longitudinal direction of the sectional shape of the flat tube  30  from the upper surface  33  of the flat tube  30 . The imaginary line Lb extends in the longitudinal direction of the section of the flat tube  30  from a lower surface  34  of the flat tube  30 . In other words, the first spacer  250   a  is disposed in a region obtained by projecting the flat tube  30  in a direction along the longitudinal direction of the section of the flat tube  30 . 
     The first spacer  250   a  and the first end portion  31  of the flat tube  30  are positioned with a predetermined separation. The cut-out portion  44  is formed in the fin  240  at a portion where the flat tube  30  is disposed and hence, the cut-out portion  44  and the first spacer  250   a  are formed to be spaced apart from each other. In Embodiment 2, the inclination angle α 1  of the first spacer  250   a  is set to a value substantially equal to the value of the inclination angle θ of the flat tube  30 . However, the inclination angle α 1  is not limited to the above, and any value within the mathematical formula of 0&lt;α 1 ≤θ may be used. 
     Advantageous Effects of Embodiment 2 
     In the heat exchanger  200  according to Embodiment 2, the first spacer  250   a  is disposed in the vicinity of the extension of the upper surface  33  of the flat tube  30  where water easily stagnates. When water on the upper surface  33  of the flat tube  30  reaches the first end portion  31 , the water is consequently guided toward the first spacer  250   a  because of capillarity, and is drained from the flat tube  30 . Further, the first spacer  250   a  is inclined by the inclination angle α 1 , so that the water guided from the flat tube  30  is easily drained also from the first spacer  250   a . In the heat exchanger  200 , water on the upper surface  33  and the lower surface  34  of the flat tube  30  is easily guided toward the first end edge  41  by the first spacer  250   a . Compared with the heat exchanger  100 ,  100   a ,  100   b  according to Embodiment 1, the heat exchanger  200  therefore has an advantageous effect that the amount of water remaining on the upper surface  33  and the lower surface  34  of the flat tube  30  easily reduces. Further, the first spacer  250   a  is disposed in a region obtained by projecting the flat tube  30  in the longitudinal direction of the section of the flat tube  30 , and is formed in such a manner that the flow of air passing across the first end edge  41  of the fin  240  is caused to flow to the upper surface  33  of the flat tube  30 . No possibility consequently remains that ventilation properties of the heat exchanger  200  are impaired. 
     As long as at least one of the first spacer  250   a  and an opening port  251   a  is disposed between the imaginary line La and the imaginary line Lb, the heat exchanger  200  according to Embodiment 2 obtains an advantageous effect of draining water on the upper surface  33  of the flat tube  30 . 
     Embodiment 3 
     A heat exchanger  300  according to Embodiment 3 is a heat exchanger obtained by changing the disposition of the second spacer  50   b  from that in the heat exchanger  100  according to Embodiment 1. The description of the heat exchanger  300  according to Embodiment 3 is made below mainly for points different from Embodiment 1. In the drawings, portions of the heat exchanger  300  according to Embodiment 3 having the same functions as those in Embodiment 1 are given the same reference signs as used in the drawings for describing Embodiment 1. 
       FIG. 14  is an explanatory view of the sectional structure of the heat exchanger  300  according to Embodiment 3.  FIG. 14  shows a section perpendicular to the pipe axes of the flat tubes  30  shown in  FIG. 1 . A second spacer  350   b  is formed on a fin  340  of the heat exchanger  300  in an intermediate region  343  that is a region between the cut-out portions  44  into which the flat tubes  30  are inserted. The flat tubes  30  of the heat exchanger  300  are inclined and hence, when air flows into the heat exchanger  300  across the first end edge  41  of the fin  340  as shown in  FIG. 12 , air passes through the heat exchanger  300  along the flat tubes  30 . 
     When the second spacer  350   b  is viewed from the first end edge  41 , that is, when the second spacer  350   b  is viewed in a direction along which air flows into the heat exchanger  300  in  FIG. 14 , the second spacer  350   b  is disposed in a region shielded by the flat tube  30 . In other words, the second spacer  350   b  is disposed in a shielded region  345  disposed behind the flat tube  30  as the second spacer  350   b  is viewed from the first end edge  41  of the fin  340 . Still further, in the intermediate region  343  between two cut-out portions  44 , the second spacer  350   b  is disposed in the shielded region  345  that is a region between a second imaginary line L 2  and the lower surface  34  of the flat tube  30 , and the second imaginary line L 2  is drawn horizontal to the width direction of the fin  340  from the lower end of the first end portion  31  of the flat tube  30 . 
     In the heat exchanger  300  according to Embodiment 3, the first spacer  50   a  may be disposed in the same manner as the heat exchanger  100 ,  100   a ,  100   b  of Embodiment 1, or the first spacer  250   a  may be disposed in the same manner as the heat exchanger  200  of Embodiment 2. Alternatively, the heat exchanger  300  may have a configuration in which only the second spacer  350   b  is provided to the fin  340 . 
     Advantageous Effects of Embodiment 3 
     In the heat exchanger  300  according to Embodiment 3, the second spacer  350   b  is disposed in the shielded region  345 , so that intervals between the fins  340  are ensured without blocking the flow of air passing through the heat exchanger  300 . The shielded region  345  below the flat tube  30  is a portion shielded by the flat tube  30  when the shielded region  345  is viewed from the upper stream of the flow of air, and is a region where the flow of air stagnates. Most of the flow of air passing through between the fins  340  passes through a region below the shielded region  345  and hence, the second spacer  350   b  does not significantly affect the flow of air passing through between the fins  340 . The heat exchanger  300  therefore maintains the intervals between the fins  340  with high accuracy while ventilation properties are ensured. Further, in the same manner as Embodiment 1 and Embodiment 2, as the second spacer  350   b  is inclined in the same direction as the flat tube  30 , drainage properties are high. In Embodiment 3, the inclination angle α 2  of the second spacer  350   b  may be set to be greater than the inclination angle θ of the flat tube  30 . The reason is as follows. In the case where air flows into the heat exchanger  300  in a direction perpendicular to the longitudinal direction of the fin  340  as shown in  FIG. 14 , the shielded region  345  where the second spacer  350   b  is disposed is a region where the flow of air stagnates and hence, ventilation properties of the heat exchanger  300  are not significantly affected. 
     REFERENCE SIGNS LIST 
       1  refrigeration cycle apparatus  2  fan  3  compressor  4  four-way valve  5  outdoor heat exchanger  6  expansion device  7  indoor heat exchanger  8  outdoor unit  9  indoor unit  10  (first) heat exchange part  20  (second) heat exchange part  30  flat tube  31  first end portion  32  second end portion  33  upper surface  34  lower surface  40  fin  41  first end edge  42  second end edge  43  intermediate region  44  cut-out portion 
       48  plate surface  50  spacer  50   a  first spacer  50   b  second spacer  51  opening port  52  contact portion  53  standing surface  53   a  standing surface  53   b  standing surface  60  header  61  header  62  header  90  refrigerant pipe  91  refrigerant pipe  92  refrigerant pipe  100  heat exchanger  100   a  heat exchanger  100   b  heat exchanger  100   c  heat exchanger  140  fin  148   a  plate surface  148   b  plate surface  150  spacer  150   a  spacer  150   b  spacer  151  opening port  153  standing surface  153   a  standing surface  153   b  standing surface  180  dotted line 
       200  heat exchanger  240  fin  241  first end edge  250   a  first spacer  251   a  opening port  300  heat exchanger  340  fin  343  intermediate region  345  shielded region  350   b  second spacer  1040  fin  1050   a  spacer  1050   b  spacer  1051   a  opening port  1051   b  opening port  1053   a  standing surface  1053   b  standing surface  1100  heat exchanger C arrow L 1  imaginary line L 2  imaginary line L 3  imaginary line La imaginary line Lb imaginary line h drainage region α 1  inclination angle 
     α 2  inclination angle θ inclination angle