Patent Publication Number: US-2019170372-A1

Title: Indoor heat exchanger

Description:
BACKGROUND 
     The present invention relates to an indoor heat exchanger, more particularly, to an indoor heat exchanger used for exchanging heat between indoor air and refrigerant. 
     As a heat exchanger used for exchanging heat with indoor air in an indoor unit of an air conditioner, there is known a cross-finned heat exchanger such as that described in Patent Literature 1 (WO 2008/041656). In this type of cross-finned heat exchanger, a dead water region is likely to occur on a leeward side of cylindrical heat transfer tubes that penetrate fins. Because there is less contribution to heat exchange at this fin portion corresponding to the dead water region, heat transfer tubes must be provided in at least three rows in order to secure necessary heat exchange capacity and increase performance. However, providing three or more rows causes the heat exchanger to increase in size. In addition, because the air that flows between these heat transfer tubes travels through a path made narrow by the heat transfer tubes, the heat transfer tubes cause air flow resistance to increase. 
     As an improvement over this type of cross-finned heat exchanger, there is, for example, described in Patent Literature 2 (WO 2013/160957) a heat exchanger that uses flat tubes in place of the tubular heat transfer tubes. In such a heat exchanger that uses flat pipes, air flow resistance is reduced. 
     However, a heat exchanger must increase in size through, for example, providing more rows of tubes in order for the heat exchanger to achieve better performance. Providing a plurality of rows of flat tubes in the heat exchanger described above may cause the fins to deform when the flat tubes are bent, and this increases air flow resistance. In addition, flat tubes are longer than cylindrical tubes in the direction in which indoor air flows, and hence it becomes difficult to discharge condensed water that is generated in the indoor heat exchanger. 
     SUMMARY 
     One or more embodiments of the present invention provide an indoor heat exchanger that reduces an increase in air flow resistance and enables easy discharge of condensed water. 
     An indoor heat exchanger according to one or more embodiments of the present invention includes a first heat exchange portion including a plurality of first flat tubes arranged in rows and a plurality of first heat transfer fins that intersect with the plurality of first flat tubes, the first heat transfer portion being configured to exchange heat between indoor air that flows in a width direction of the plurality of first flat tubes and refrigerant that flows through the plurality of first flat tubes; and a second heat exchange portion including a plurality of second flat tubes arranged in rows and a plurality of second heat transfer fins that intersect with the plurality of second flat tubes, the second heat transfer portion being configured to exchange heat between indoor air that flows in a width direction of the plurality of second flat tubes and refrigerant that flows through the plurality of second flat tubes, the plurality of first heat transfer fins and the plurality of second heat transfer fins each including a windward main portion formed with a notch that receives the first flat tube and the second flat tube respectively, and a leeward communication portion located on a side opposite to an open end of the notch, and, in the first heat exchange portion and the second heat exchange portion, the plurality of first flat tubes and the plurality of second flat tubes in the rows being arranged in a width direction, and the first heat exchange portion and the second heat exchange portion each having a bent shape with an inner peripheral side on a windward side and an outer peripheral side on a leeward side. 
     According to the indoor heat exchanger of one or more embodiments of the present invention, because the notches of the first heat transfer fins and the second heat transfer fins are disposed inward and the first flat tubes and the second flat tubes each have an inwardly bent shape, deformation of the main portions of the first heat transfer fins and the main portions of the second heat transfer fins is reduced. Because the communication portions of the first heat transfer fins and the second heat transfer fins are disposed on a leeward side, condensed water guided by the indoor air traveling in the width direction of the first flat tubes and the second flat tubes can be sent in an up-down direction via the communication portion. 
     An indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the first heat exchange portion and the second heat exchange portion each have the bent shape so as to surround an indoor fan with the inner peripheral sides, and are disposed such that indoor air discharged from the indoor fan disposed on the inner peripheral side can be guided along the width direction of the plurality of first flat tubes and the plurality of second flat tubes to pass between the plurality of first heat transfer fins and between the plurality of second heat transfer fins and reach the outer peripheral side on which the communication portion of the second heat transfer fins is located. 
     According to the indoor heat exchanger of one or more embodiments of the present invention, the indoor air discharged from the indoor fan surrounded by the inner peripheral sides of the first heat exchange portion and the second heat exchange portion can be discharged in the width direction of the first flat tubes and the second flat tubes, which has low air flow resistance. In addition, condensed water can be sent across the entire indoor heat exchanger from the inner peripheral sides to the outer peripheral sides of the first heat exchange portion and the second heat exchange portion. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the plurality of first flat tubes are disposed so as to be positioned windward of windward edges of the plurality of first heat transfer fins by 0 mm or more. 
     According to the indoor heat exchanger according to one or more embodiments of the present invention, because the plurality of first flat tubes are positioned windward of the windward edges of the plurality of first heat transfer fins by 0 mm or more, the first flat tubes protrude leeward of the windward edges of the first heat transfer fins by 0 mm or more, and hence first abut against a member or other component when, for example, the first heat exchange portion and the second heat exchange portion are bent. This reduces the occurrence of buckling of the windward edges of the plurality of first heat transfer fins, for example. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which, in the plurality of first flat tubes arranged in rows and the plurality of second flat tubes arranged in rows, a thickness of tube walls at a windward portion located windward is larger than a thickness of tube walls at a side portion located in a row direction of the plurality of first flat tubes and the plurality of second flat tubes. 
     According to the indoor heat exchanger according to one or more embodiments of the present invention, because the tube walls at the windward portion located windward are thick, a reduction in compressive strength can be suppressed even if the first flat tubes and the second flat tubes are damaged by a jig when the first flat tubes and the second flat tubes are bent using the jig. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the first heat exchange portion is configured so as not to make contact with the second heat exchange portion due to a clearance that is located between leeward edges of the plurality of first heat transfer fins of the first heat exchange portion and the windward main portions of the plurality of second heat transfer fins of the second heat exchange portion. 
     According to the indoor heat exchanger according to one or more embodiments of the present invention, because the first heat exchange portion and the second heat exchange portion, which have different temperatures, are configured such as not to make contact with each other, heat transfer can be reduced from one of the first heat exchange portion and the second heat exchange portion to the other. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the plurality of second flat tubes are arranged so as to be positioned windward of windward edges of the plurality of second heat transfer fins by 0 mm or more. 
     According to the indoor heat exchanger of one or more embodiments of the present invention, because the plurality of second flat tubes are positioned windward of the windward edges of the plurality of second heat transfer fins by 0 mm or more, the clearance between the first heat exchange portion and the second heat exchange portion can be easily maintained. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the plurality of second flat tubes are disposed so as to be positioned windward of the windward edges of the plurality of second heat transfer fins by 2 mm or less. 
     According to the indoor heat exchanger of one or more embodiments of the present invention, because the plurality of second flat tubes are positioned windward of the windward edges of the plurality of second heat transfer fins by 2 mm or less, condensed water is more likely to be drawn by surface tension into a clearance of 2 mm or less formed between the first heat exchange portion and the second heat exchange portion, to flow and drop down. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the leeward edges of the plurality of first heat transfer fins in the first heat exchange portion extend in a straight line along the clearance in a vertical direction. 
     According to the indoor heat exchanger of one or more embodiments of the present invention, because the leeward edges of the plurality of first heat transfer fins extend in a straight line along the clearance in a vertical direction, condensed water is more likely to be guided along the leeward edges. 
     The indoor heat exchanger according to one or more embodiments of the present invention is an indoor heat exchanger in which the first heat exchange portion and the second heat exchange portion each have an L-shape, a C-shape, or a rectangular shape when viewed from the row direction of the plurality of first flat tubes and the plurality of second flat tubes. 
     According to the indoor heat exchanger of one or more embodiments of the present invention, because the first heat exchange portion and the second heat exchange portion each have an L-shape, a C-shape, or a rectangular shape, windward space can be surrounded by either one or two pairs of the first heat exchange portion and the second heat exchange portion. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, an increase in air flow resistance is reduced and the leeward communication portion improves drainability of water when condensation occurs. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, drainability of condensed water can be improved by efficiently utilizing air flow discharged around by the indoor fan. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, an increase in air flow resistance caused by deformation of the windward edges of the plurality of first heat transfer fins can be reduced. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, decrease of compressive strength of the first flat tubes and the second flat tubes at inwardly bent portions is suppressed due to damage from a jig. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, heat exchange capacity is less likely to decrease due to thermal conduction between the first heat exchange portion and the second heat exchange portion. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, it becomes easy to prevent the degradation of the performance of the first heat exchange portion and the second heat exchange portion due to thermal conduction between the first heat exchange portion and the second heat exchange portion. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, drainability of condensed water is improved. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, problems caused by condensed water, such as condensed water splashing outward, can be reduced. 
     In the indoor heat exchanger according to one or more embodiments of the present invention, the configuration of the device to which the indoor heat exchanger is applied can be simplified. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view for illustrating the external appearance of an indoor unit according to one or more embodiments. 
         FIG. 2  is a cross-sectional view of the indoor unit in  FIG. 1 . 
         FIG. 3  is a schematic plan view of an indoor heat exchanger according to one or more embodiments. 
         FIG. 4  is a cross-sectional view for illustrating the structure of the indoor heat exchanger and the vicinity thereof taken along the line I-I in  FIG. 3 . 
         FIG. 5  is a schematic view from above illustrating the indoor heat exchanger functioning as an evaporator according to one or more embodiments. 
         FIG. 6  is a partially enlarged cross-sectional view of an exemplary relationship between first and second flat tubes and notches according to one or more embodiments. 
         FIG. 7  is a schematic view for illustrating an exemplary process of manufacturing the indoor heat exchanger according to one or more embodiments. 
         FIG. 8  is a schematic view for illustrating another exemplary process of manufacturing the indoor heat exchanger according to one or more embodiments. 
         FIG. 9  is a cross-sectional view for schematically illustrating the relationship between indoor heat exchanger parts and jigs according to one or more embodiments. 
         FIG. 10  is a cross-sectional view for explaining wall thicknesses of the first flat tube and the second flat tube according to one or more embodiments. 
         FIG. 11  is a partially enlarged cross-sectional view of a first heat exchange portion and a second heat exchange portion according to one or more embodiments. 
         FIG. 12  is a schematic view from above for illustrating an indoor heat exchanger according to a modification example 1A. 
         FIG. 13  is a schematic view from above for illustrating another indoor heat exchanger according to the modification example 1A. 
         FIG. 14  is a diagram for illustrating an internal structure of an indoor unit according to a modification example 1B when viewed from below. 
         FIG. 15  is a cross-sectional view of the indoor unit taken along the line II-II in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     (1) Outline of Configuration of Air Conditioner 
       FIG. 1  illustrates the external appearance of an indoor unit to which an indoor heat exchanger according to one or more embodiments of the present invention is applied.  FIG. 2  illustrates the internal structure of the indoor unit in  FIG. 1 . An indoor unit  100  is a ceiling-mounted indoor unit that is used to heat and cool a room inside, for example, a building such as a high-rise building through performing a vapor-compression refrigeration cycle. As illustrated in  FIG. 2 , the indoor unit  100  is installed into a ceiling CE of a room inside a building such as a high-rise building. The indoor unit  100  includes an indoor fan  120  and an indoor heat exchanger  10 . In the indoor unit  100 , the indoor fan  120  operates to suck in indoor air through an intake port  101  provided on a lower center part of the indoor unit  100  and discharge this air from four discharge ports  102  provided in the indoor unit  100 . The four discharge ports  102  of the indoor unit  100  extend parallel to the four sides of a decorative plate  103  having a substantially square-shaped lower surface, respectively. 
     Inside the indoor unit  100 , a bell mouth  104  is mounted directly above the intake port  101 . The indoor air sucked in through the intake port  101  is guided to the indoor fan  120  using this bell mouth  104 . The indoor air is discharged from the indoor fan  120  in a direction substantially parallel to the ceiling CE. Then, the indoor air passes through the indoor heat exchanger  10  that surrounds the indoor fan  120  in a horizontal direction to be discharged from the indoor fan  120  and then discharged from the four discharge ports  102  located further outside than the indoor heat exchanger  10 . 
     Condensation may occur in the indoor heat exchanger  10  when, for example, the temperature of the indoor heat exchanger  10  becomes lower than the temperature of the room during a cooling operation. In the indoor unit  100 , a drain pan  130  is provided beneath the indoor heat exchanger  10  to receive condensed water generated by condensation in the indoor heat exchanger  10 . The condensed water generated in the indoor heat exchanger  10  is pulled by gravity so as to flow down through the indoor heat exchanger  10  and drop from the indoor heat exchanger  10  into the drain pan  130 . 
     (2) Indoor Heat Exchanger  10   
       FIG. 3  illustrates a state in which the indoor heat exchanger  10  is viewed from above. As illustrated in  FIG. 3 , the indoor heat exchanger  10  surrounds the indoor fan  120 . The arrows Ar 1 , Ar 2 , Ar 3  and Ar 4  in  FIG. 3  indicate the direction of air flow. The four discharge ports  102  are formed in the directions in which these arrows Ar 1  to Ar 4  face, respectively. When viewed from above, the indoor heat exchanger  10  has a shape similar to the four sides of a square with a diagonal center at the center of the indoor fan  120 . However, a portion corresponding to where a drain pump  140  is located is recessed toward the inner periphery of the indoor heat exchanger  10 . 
     The indoor heat exchanger  10  is, for example, a device that partly forms a refrigerant circuit (not illustrated) which performs a refrigerant cycle and exchanges heat between refrigerant that flows through the refrigerant circuit and indoor air. A liquid pipe  51  and a gas pipe  52  that extend outward from the indoor heat exchanger  10  are connected to the refrigerant circuit. Liquid refrigerant and gas refrigerant primarily flow through the liquid pipe  51  and the gas pipe  52  that extend outward from the indoor heat exchanger  10 , respectively. 
     (2-1) First Heat Exchange Portion  11  and Second Heat Exchange Portion  12   
       FIG. 4  illustrates in an enlarged manner a partial cross-sectional structure of the indoor unit  100  at a place corresponding to a portion taken along the line I-I in  FIG. 3 . As illustrated in  FIG. 4 , the indoor heat exchanger  10  includes a first heat exchange portion  11  on an inner peripheral side and a second heat exchange portion  12  on an outer peripheral side. In other words, the first heat exchange portion  11  is disposed on a windward side and the second heat exchange portion  12  is disposed on a leeward side. The first heat exchange portion  11  includes a plurality of first flat tubes  21  arranged in rows and a plurality of first heat transfer fins  31  that intersect with the plurality of first flat tubes  21 . The first flat tubes  21  and the first heat transfer fins  31  are substantially orthogonal to one another. Only one first heat transfer fin  31  is illustrated in  FIG. 4 . Other first heat transfer fins  31  that are adjacent to the first heat transfer fin  31  illustrated in  FIG. 4  are arranged parallel to the first heat transfer fin  31  in  FIG. 4 . However, at bent portions  10 R of the indoor heat exchanger  10 , these adjacent first heat transfer fins  31  are not parallel to one another, and an interval between outer peripheral sides of the adjacent first heat transfer fins  31  is larger than an interval between inner peripheral sides of the adjacent first heat transfer fins  31 . A plurality of flow paths  21   a  are formed as one windward-to-leeward row inside one first flat tube  21 , and refrigerant flows through each of these flow paths  21   a.    
     The second heat exchange portion  12  includes a plurality of second flat tubes  22  arranged in rows and a plurality of second heat transfer fins  32  that intersect with the plurality of second flat tubes  22 . The second flat tubes  22  and the second heat transfer fins  32  are substantially orthogonal to one another. Only one second heat transfer fin  32  is illustrated in  FIG. 4 . Other second heat transfer fins  32  that are adjacent to the second heat transfer fin  32  illustrated in  FIG. 4  are arranged parallel to the second heat transfer fin  32  in  FIG. 4 . However, at the bent portions  10 R of the indoor heat exchanger  10 , these adjacent second heat transfer fins  32  are not parallel to one another, and an interval between outer peripheral sides of the adjacent second heat transfer fins  32  is larger than an interval between inner peripheral sides of the adjacent second heat transfer fins  32 . A plurality of flow paths  22   a  are formed as one windward-to-leeward row inside one second flat tube  22 , and the refrigerant flows through each of these flow paths  22   a.    
       FIG. 5  schematically illustrates an exemplary direction of flow of the refrigerant that flows through the indoor heat exchanger  10 . The indoor heat exchanger  10  includes a flow divider  53  connected to the liquid pipe  51 , a liquid header  54  connected to the flow divider  53 , a gas header  55  connected to the gas pipe  52 , and a return header  56 . The indoor heat exchanger  10  illustrated in  FIGS. 3 and 5  includes two pairs of the first heat exchange portion  11  and the second heat exchange portion  12 . The pair of heat exchange portions disposed near the drain pump  140  is referred to as a “first pair P 1  of the first heat exchange portion  11  and the second heat exchange portion  12 ” or the “first pair P 1 ” and the other pair of heat exchange portions is referred to as a “second pair P 2  of the first heat exchange portion  11  and the second heat exchange portion  12 ” or the “second pair P 2 .” 
     In  FIG. 5 , the flow of refrigerant when the indoor heat exchanger  10  functions as an evaporator is indicated by the arrows Ar 5  to Ar 8 . In the first pair P 1 , liquid refrigerant flows in the direction of the arrow Ar 5  after traveling from the liquid pipe  51  to the first flat tube  21  via the flow divider  53  and the liquid header  54 . Then, the refrigerant that flows through the first flat tube  21  of the first pair P 1  is returned by the return header  56  and flows from the first flat tube  21  into the second flat tube  22 . The refrigerant then travels in the direction of the arrow Ar 6  to the gas pipe  52  via the gas header  55 . In the second pair P 2 , liquid refrigerant flows in the direction of the arrow Ar 7  after traveling from the liquid pipe  51  to the first flat tube  21  via the flow divider  53  and the liquid header  54 . Then, the refrigerant that flows through the first flat tube  21  of the second pair P 2  is returned by the return header  56  and flows from the first flat tube  21  into the second flat tube  22 . The refrigerant then flows in the direction of the arrow Ar 8  to the gas pipe  52  via the gas header  55 . In the indoor heat exchanger  10  illustrated in  FIG. 5 , liquid refrigerant changes to gas refrigerant by evaporating while flowing through the first flat tube  21  and the second flat tube  22 . The indoor heat exchanger  10  illustrated in  FIG. 5  is formed of a combination of the L-shaped first pair P 1  of the first heat exchange portion  11  and the second heat exchange portion  12  and the L-shaped second pair P 2  of the first heat exchange portion  11  and the second heat exchange portion  12 . Note that the first pair P 1  has two bent portions  10 R and the second pair P 2  only has one bent portion  10 R. The shapes of all of these bent portions  10 R are classified as an L-shape. 
     As described above, the first pair P 1  and the second pair P 2  each have an L-shape such that inner peripheral sides of the first heat exchange portion  11  and the second heat exchange portion  12  surround the indoor fan  120 . Both the first pair P 1  and the second pair P 2  are disposed such that indoor air discharged from the indoor fan  120 , which is disposed on the inner peripheral side, can be guided along a width direction of the first flat tubes  21  and the second flat tubes  22  to pass between a plurality of the first heat transfer fins  31  and a plurality of the second heat transfer fins  32  and reach an outer peripheral side on which a communication portion  34  (see  FIG. 6 ) of the second heat transfer fin  32  is located. 
     (2-2) Detailed Configuration of First Heat Transfer Fin  31   
       FIG. 6  illustrates in a further enlarged manner a part of the first heat transfer fin  31  and the first flat tube  21  that is fitted into the first heat transfer fin  31  in the first heat exchange portion  11  illustrated in  FIG. 4 . The second heat exchange portion  12  has the same structure as that of the first heat exchange portion  11  illustrated in the enlarged manner in  FIG. 6 . Therefore, herein, the first heat exchange portion  11  is described, but a description of components of the second heat exchange portion  12  that are the same as those of the first heat exchange portion  11  is omitted. 
     The first heat transfer fin  31  includes a windward main portion  33  formed with a notch  35  that receives the first flat tube  21 , and the leeward communication portion  34  located on a side opposite to an open end  35   a  of the notch  35 . The first flat tube  21  is inserted in the direction of the arrow Ar 9  in  FIG. 6 . Similarly, the second heat transfer fin  32  includes the windward main portion  33  formed with the notch  35  that receives the second flat tube  22 , and the leeward communication portion  34  located on a side opposite to the open end  35   a  of the notch  35 . A water guide rib  36  that facilitates condensed water discharge is formed in the communication portion  34 . This guide rib  36  is a portion that extends from a pressed groove. A protruded structure extends in the up-down direction along the guide rib  36  when the guide rib  36  is viewed from one main surface f 1  of the first heat transfer fin  31  (or the second heat transfer fin  32 ), while a recessed structure extends in the up-down direction along the guide rib  36  when the guide rib  36  is viewed from the other main surface on a side opposite to the one main surface f 1 . A plurality of raised-lance portions  37  are formed on the one main surface f 1  side of the first heat transfer fin  31  (or the second heat transfer fin  32 ). Each of the raised-lance portions  37  protrudes in a bridge shape. As seen in  FIG. 6 , the raised-lance portions  37  are not formed around the notches  35 . 
     (3) Bending Parts of the Indoor Heat Exchanger  10   
     (3-1) Summary of Bending 
     A method of forming the bent portions  10 R of the indoor heat exchanger  10  illustrated in  FIG. 3  is described with reference to  FIGS. 7 to 9 . Two jigs are used to form the bent portions  10 R. Examples of such jigs are illustrated in  FIGS. 7 and 8 . In other words, the bent portions  10 R of the indoor heat exchanger  10  is formed using a rolling jig  210  and a pressing jig  220 . As illustrated in  FIG. 7 , the rolling jig  210  is brought into contact with a position at which the bent portion  10 R is to be formed, and fixed to a part  300  of the indoor heat exchanger  10  on a side of an end  301  of the part  300 . Then, the pressing jig  220  is pressed against the part  300  from a side opposite to a rolling part  211  of the rolling jig  210 . The pressing jig  220  is pressed against the part  300  at a position that is closer to the other end  302  of the part  300  than the position of the rolling part  211 . 
     Next, as illustrated in  FIG. 8 , the pressing jig  220  applies force to the part  300  of the indoor heat exchanger  10  to bend the first flat tube  21  and the second flat tube  22  of the part  300 . The curvature radius of the second flat tube  22  is larger than that of the first flat tube  21  at the position where the bent portion  10 R is formed. Thus, as illustrated in  FIG. 7 , an end of the second flat tube  22  is designed to protrude further outward than an end of the first flat tube  21  before the part  300  is bent so that the ends of the first flat tube  21  and the second flat tube  22  are not arranged too far apart from each other at the other end  302  of the part  300  when bending is completed. 
       FIG. 9  illustrates a portion of the part  300  in an enlarged manner. In  FIG. 9 , the rolling jig  210  and the pressing jig  220  are pushed against the part  300 . As is evident from  FIG. 9 , it is mainly the first flat tube  21  that makes contact with the rolling jig  210 . Although not illustrated in  FIG. 9 , upon completion of this step, a plate is interposed between the first heat exchange portion  11  and the second heat exchange portion  12  during bending. In other words, force is transmitted from the second flat tube  22  to the first heat transfer fin  31  via the plate during bending. Similarly, the area in which the pressing jig  220  comes into contact with the second heat transfer fin  32  is large. Pressure applied to the second heat transfer fin  32  by the pressing jig  220  and pressure applied to the first heat transfer fin  31  by the plate are both smaller than pressure applied to the first flat tube  21  by the rolling jig  210 . As a result, buckling of a leeward edge  31   b  of the first heat transfer fin  31  and a leeward edge  32   b  of the second heat transfer fin  32  (see  FIG. 11 ) is less likely to occur during the bending. 
     (3-2) Positional Relationship Between Flat Tube and Heat Transfer Fin 
     As illustrated in  FIG. 6 , the plurality of first flat tubes  21  are disposed so as to be positioned windward of windward edges  31   a  of the plurality of first heat transfer fins  31  by 0 mm or more. In other words, a distance D 1  illustrated in  FIG. 6  between a windward end portion of the first flat tube  21  and the windward edge  31   a  of the first heat transfer fin  31  is 0 mm or more, and may be set to 0.5 mm or more in consideration of, for example, manufacturing errors. As described above, the first flat tube  21  may protrude outward in order to reduce the amount of force applied to the first heat transfer fin  31  during the bending. 
     In addition, during bending, force is applied to the first flat tube  21  by the rolling jig  210  and to the second flat tube  22  by the plate interposed between the first flat tube  21  and the second flat tube  22 . The wall thicknesses of the first flat tube  21  and the second flat tube  22  are set in consideration of the force. More specifically, as illustrated in  FIG. 10 , a thickness t 3  of tube walls  21   d ,  22   d  at windward portions located on the windward side of the first flat tube  21  and the second flat tube  22  is larger than a thickness t 2  of the tube walls  21   c ,  22   c  at side portions located in the row direction of the first flat tubes  21  and the second flat tubes  22 . The thickness t 3  of the tube walls  21   d ,  22   d  at the windward portion located on the windward side is larger than a thickness t 1  of inner walls  21   b ,  22   b  that divide flow paths of the multi-hole first flat tubes  21  and second flat tubes  22 . 
       FIG. 11  illustrates in an enlarged manner a part of the first heat exchange portion  11  and the second heat exchange portion  12 . The first heat exchange portion  11  is configured such as not to make contact with the second heat exchange portion  12  through a clearance CL that is located between the leeward edge  31   b  of the first heat transfer fin  31  and the windward main portion  33  of the second heat transfer fin  32  of the second heat exchange portion  12 . More specifically, the leeward edges  31   b  of the plurality of first heat transfer fins  31  of the first heat exchange portion  11  extend in a straight line along the clearance CL in a vertical direction. A distance of 2 mm or less may be allocated for the distance D 3  between the leeward edge  31   b  of the first heat transfer fin  31  and the windward edge  32   a  of the second heat transfer fin  32 . 
     As illustrated in  FIG. 6 , the plurality of second flat tubes  22  are disposed so as to be positioned windward of the windward edges  32   a  of the plurality of second heat transfer fins  32  by 0 mm or more. In other words, the distance D 2  illustrated in  FIG. 6  between a windward end portion of the second flat tube  22  and the windward edge  32   a  of the second heat transfer fin  32  is 0 mm or more, and may be set to 2 mm or less such that condensed water is more easily drawn by surface tension to flow and drop downward. This distance of 2 mm is set in consideration of the size of water droplets. If this distance is set 2 mm or more, water droplets are not as easily drawn down by surface tension (capillary action). In addition, in order to reduce the force applied to the second heat transfer fin  32  during bending, the second flat tube  22  may protrude outward (the second flat tube  22  may protrude outward by more than 0 mm from the windward edge  32   a  of the second heat transfer fin  32  and is positioned windward). 
     (4) Modification Example 
     (4-1) Modification Example 1A 
     In the above-described embodiments, the indoor heat exchanger  10  is described by taking an example in which the indoor heat exchanger  10  is configured to enclose the entire periphery of windward space in which the indoor fan  120  is disposed when viewed from the row direction of the first flat tubes  21  and the second flat tubes  22  through the combination of the L-shaped first pair P 1  and the L-shaped second pair. However, the shape of the indoor heat exchanger  10  for surrounding the windward space in which the indoor fan  120  is disposed may be, for example, rectangular when viewed from the row direction of the first flat tubes  21  and the second flat tubes  22 , such as that illustrated in  FIG. 12 or 13 . 
     In  FIG. 12 , the arrows Ar 11 , Ar 12  indicate the flow of refrigerant when a rectangular indoor heat exchanger  10  functions as an evaporator. Liquid refrigerant flows in the direction of the arrow Ar 11  after traveling from the liquid pipe  51  to the first flat tube  21  via the flow divider  53  and the liquid header  54 . Then, the refrigerant that flows through the first flat tube  21  is returned by the return header  56  and flows from the first flat tube  21  into the second flat tube  22 . The refrigerant then travels in the direction of the arrow Ar 12  to the gas pipe  52  via the gas header  55 . 
     In  FIG. 13 , the arrows Ar 12 , Ar 14  indicate the flow of refrigerant in the first flat tube  21  of the first heat exchange portion  11  and the arrows Ar 13 , Ar 15  indicate the flow of refrigerant in the second flat tube  22  of the second heat exchange portion  12  when the rectangular indoor heat exchanger  10  functions as an evaporator. Liquid refrigerant flows in the directions of the arrows Ar 12 , Ar 13  after traveling from the liquid pipe  51  to the first flat tube  21  via the flow divider  53  and the liquid header  54 . Then, the refrigerant that flows through the first flat tube  21  flows in the direction of the arrows Ar 14 , Ar 15  to the gas pipe  52  via the gas header  55 . 
     (4-2) Modification Example 1B 
     In the above-described embodiments, the indoor heat exchanger  10  is described as surrounds the entire periphery of the indoor fan  120 , but the indoor heat exchanger  10  may have a configuration that does not surround part of the periphery of the indoor fan. For example, the indoor heat exchanger  10  may have a C-shape such as that illustrated in  FIGS. 14 and 15  when viewed from the row direction of the first flat tubes  21  and the second flat tubes  22 . 
       FIG. 14  illustrates the internal structure of the indoor unit  100  when viewed from below, and  FIG. 15  illustrates a cross-sectional structure of the indoor unit  100  taken along the line II-II in  FIG. 14 . The indoor unit  100  includes the indoor fan  120  and the indoor heat exchanger  10 . In  FIG. 14 , the C-shaped indoor heat exchanger  10  is the hatched portion. In the indoor unit  100 , the indoor fan  120  operates to suck in indoor air through the intake port  101  provided on a lower center part of the indoor unit  100  and discharge this air from the discharge port  102  of the indoor unit  100 . 
     The bell mouth  104  is mounted directly above the intake port  101  in the indoor unit  100 . The indoor air sucked in through the intake port  101  is guided to the indoor fan  120  using this bell mouth  104 . The indoor air is then discharged from the indoor fan  120  in a substantially horizontal direction. The indoor air passes through the C-shaped indoor heat exchanger  10  that surrounds the indoor fan  120  in a horizontal direction to be discharged from the indoor fan  120  and then discharged from the discharge port  102 . 
     Condensation may occur in the indoor heat exchanger  10  when, for example, the temperature of the indoor heat exchanger  10  becomes lower than the temperature of the room during a cooling operation. In the indoor unit  100 , the drain pan  130  is provided beneath the indoor heat exchanger  10  to receive condensed water generated in the indoor heat exchanger  10 . The condensed water generated in the indoor heat exchanger  10  is pulled by gravity so as to flow down through the indoor heat exchanger  10  and drop from the indoor heat exchanger  10  into the drain pan  130 . 
     (4-3) Modification Example 1C 
     The refrigerant that flows through the first flat tube  21  and the second flat tube  22  according to the above-described embodiments may be a substance other than refrigerant for vapor compression refrigerant, for example, water. 
     (4-4) Modification Example 1D 
     In the indoor heat exchanger  10  according to one or more embodiments, two rows of heat exchange portions, that is, the first heat exchange portion  11  and the second heat exchange portion  12  are provided, but the present invention can also be applied to an indoor heat exchanger having three or more rows of heat exchange portions. 
     (4-5) Modification Example 1E 
     The indoor heat exchanger according to the present invention is not limited to being applied to the ceiling-mounted indoor unit  100  and can also be applied to, for example, an indoor unit that hangs from a ceiling. 
     (4-6) Modification Example 1F 
     In the above-described embodiments, the first flat tubes  21  and the second flat tubes  22  are arranged at the same height, but the first flat tubes and the second flat tubes in the indoor heat exchanger according to the present invention may be arranged in a staggered fashion. 
     (5) Characteristics 
     (5-1) 
     As described above, the notches  35  in the first heat transfer fin  31  and the second heat transfer fin  32  are disposed inward and the first flat tube  21  and the second flat tube  22  each have an inwardly bent shape. This configuration reduces deformation of the main portions  33  of the first heat transfer fin  31  and the second heat transfer fin  32 . As a result, because deformation of the main portions  33  of the first heat transfer fin  31  and the second heat transfer fin  32  is reduced, there is less possibility of increasing air flow resistance caused by such deformation and an increase in air flow resistance is thereby reduced. 
     In addition, because the communication portions  34  of the first heat transfer fin  31  and the second heat transfer fin  32  are disposed on a leeward side, condensed water guided by the indoor air traveling in the width direction of the first flat tubes  21  and the second flat tubes  22  can be sent in the up-down direction via the communication portions  34 , particularly guide ribs  36 . In this way, drainability when condensation occurs is improved due to the leeward communication portions  34  of the first flat tube  21  and the second flat tube  22 . 
     (5-2) 
     In the above-described embodiments, as illustrated in  FIG. 5 , the first pair P 1  and the second pair P 2  of the indoor heat exchanger  10  each have an L-shape so as to surround the indoor fan  120  with the inner peripheral sides thereof. In the modification example 1A, the indoor heat exchanger  10  illustrated in  FIGS. 12 and 13  is rectangular so as to surround the indoor fan  120  with the inner peripheral side thereof. Further, in modification example 1B, the indoor heat exchanger  10  illustrated in  FIG. 14  has a C-shape so as to surround the indoor fan  120  with the inner peripheral side thereof. With these configurations, indoor air discharged from the indoor fan  120  arranged on the inner peripheral side is guided along the width direction of the first flat tubes  21  and the second flat tubes  22  to pass between a plurality of the first heat transfer fins  31  and a plurality of the second heat transfer fins  32  and reach the outer peripheral side on which the communication portion  34  of the second heat transfer fin  32  is located. As a result, in the indoor heat exchanger  10 , drainability of condensed water is improved by efficiently utilizing air flow discharged around by the indoor fan  120 . 
     (5-3) 
     As described with reference to  FIG. 6 , the first flat tubes  21  are positioned windward of the windward edges  31   a  of the plurality of first heat transfer fins  31  by 0 mm or more. With this configuration, the first flat tubes  21  protrude leeward of the windward edges  31   a  of the first heat transfer fins  31  by 0 mm or more, and hence first abut against a member such as the rolling jig  210  when, for example, the first heat exchange portion  11  and the second heat exchange portion  12  are bent. This reduces the possibility of buckling of the windward edges  31   a  of the plurality of first heat transfer fins  31 , for example. As a result, an increase in air flow resistance caused by deformation of the windward edges  31   a  of the plurality of first heat transfer fins  31  can be reduced. 
     (5-4) 
     When a thickness tt 3  of the tube wall  21   d ,  22   d  at the windward portion located windward is larger than the thickness t 2  of the tube wall  21   c ,  22   c  at the side surface portion as illustrated in  FIG. 10 , a reduction in compressive strength can be suppressed even if the first flat tube  21  and the second flat tube  22  are damaged by the rolling jig  210  when the first flat tube  21  and the second flat tube  22  are bent by the rolling jig  210 . As a result, the compressive strength of the first flat tubes  21  and the second flat tubes  22  at bent portions toward the inner peripheral side of the indoor heat exchanger  10  is less likely to decrease. 
     (5-5) 
     By adopting a configuration such as that illustrated in  FIG. 11  in which the first heat exchange portion  11  and the second heat exchange portion  12 , which have different temperatures, are configured not to make contact with each other through the clearance CL that is located between the leeward edge  31   b  of the first heat transfer fin  31  and the windward main portion  33  of the second heat transfer fin  32 , heat transfer can be reduced from one of the first heat exchange portion  11  and the second heat exchange portion  12  to the other. As a result, heat exchange capacity of the first heat exchange portion  11  and the second heat exchange portion  12  is less likely to decrease due to thermal conduction between the first heat exchange portion  11  and the second heat exchange portion  12 . 
     (5-6) 
     As illustrated in  FIG. 11 , because the second flat tubes  22  are positioned windward of the windward edges  32   a  of the plurality of second heat transfer fins  32  by 0 mm or more, the clearance CL can be easily left between the first heat exchange portion  11  and the second heat exchange portion  12 . When the clearance CL is left by arranging the second flat tubes  22  in this way, heat exchange capacity is less likely to decrease due to thermal conduction between the first heat exchange portion  11  and the second heat exchange portion  12 . 
     (5-7) 
     As illustrated in  FIG. 11 , because the second flat tubes  22  are positioned windward of the windward edges of the plurality of second heat transfer fins by 2 mm or less, a clearance CL of 2 mm or less can be reliably formed between the first heat exchange portion  11  and the second heat exchange portion  12 . In other words, the distance D 3  between the leeward edge  31   b  of the first heat transfer fin  31  and the windward edge  32   a  of the second heat transfer fin  32  is 2 mm or less. Condensed water is more likely to be drawn by surface tension into this clearance of 2 mm or less formed between the first heat exchange portion  11  and the second heat exchange portion  12 , to flow and drop down. As a result, condensed water in the indoor heat exchanger  10  is drained with better performance. 
     (5-8) 
     As illustrated in  FIG. 11 , because the leeward edges  31   b  of the plurality of first heat transfer fins  31  extend in a straight line along the clearance CL in a vertical direction, condensed water is more likely to be guided along these leeward edges  31   b . As a result, problems caused by condensed water, such as condensed water splashing outward, can be reduced. 
     (5-9) 
     The windward space can be surrounded by two L-shaped pairs of the first heat exchange portion  11  and the second heat exchange portion  12 , namely, the first pair P 1  and the second pair P 2  as illustrated in  FIG. 5 , one rectangular pair of the first heat exchange portion  11  and the second heat exchange portion  12  as illustrated in  FIGS. 12 and 13 , or one C-shaped pair of the first heat exchange portion and the second heat exchange portion as illustrated in  FIG. 14 . As a result, the configuration of the indoor unit  100  to which the indoor heat exchanger  10  is applied can be simplified. 
     Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims. 
     REFERENCE SIGNS LIST 
     
         
           10  Indoor heat exchanger 
           11  First heat exchange portion 
           12  Second heat exchange portion 
           21  First flat tube 
           21   b ,  21   c ,  21   d  Tube wall 
           22  Second flat tube 
           22   b ,  22   c ,  22   d  Tube wall 
           31  First heat transfer fin 
           31   a  Windward edge 
           31   b  Leeward edge 
           32  Second heat transfer fin 
           32   a  Windward edge 
           32   b  Leeward edge 
           33  Main portion 
           34  Communication portion 
           35  Notch 
       
    
     CITATION LIST 
     Patent Literature 
     
         
         [Patent Literature 1] WO 08/41656 
         [Patent Literature 2] WO 13/160957