Heat exchanger and air conditioning device comprising same

Abstract

A heat exchanger and an air-conditioning apparatus including the heat exchanger include: heat transfer tubes allowing a fluid to flow therethrough, and each having both ends in a tube axial direction that are sealed, the heat transfer tubes being arranged in a first direction crossing the tube axial direction; a tube pitch defining part that defines the tube pitch of the heat transfer tubes in the first direction; and one or more headers penetrating the heat transfer tubes in the first direction to couple the heat transfer tubes together. Each of the heat transfer tubes has one or more header insertion holes into which the one or more headers are inserted, and which extend through the heat transfer tube in the first direction, and each of the one or more headers has communication holes each causing the header to communicate with the inside of an associated heat transfer tube.

Description

Technical Field

[0001] The present invention relates to a heat exchanger including a plurality of heat transfer tubes, and to an air-conditioning apparatus including the heat exchanger.Background Art

[0002] There are provided heat exchangers each including a plurality of heat transfer tubes spaced from each other and headers (see Patent Literature 1, for example). In a heat exchanger disclosed in Patent Literature 1, header flow passages provided in the headers communicate with heat transfer passages provided in the heat transfer tubes.Citation ListPatent Literature

[0003] Patent Literature 1: Japanese Unexamined Patent Application Publication JP 2001 - 280 884 ASummary of InventionTechnical Problem

[0004] However, in the heat exchanger of Patent Literature 1, each of the headers is formed to have tube holes into which end portions of the heat transfer tubes are inserted and which are arranged apart from each other. Thus, the pitch of the heat transfer tubes depends on the arrangement of the tube holes of the header. On peripheral portions of the holes of the header, a force for support of the heat transfer tubes acts. Thus, in order that the pitch of the heat transfer tubes be reduced, the pitch of the tube holes of the header is reduced, and the peripheral portions of the holes cannot secure a necessary strength. Accordingly, it is hard to reduce the pitch of the heat transfer tubes.

[0005] The present invention is applied to solve the above problem, and relates to a heat exchanger and an air-conditioning apparatus including the heat exchanger, in which the pitch of heat transfer tubes (which will be hereinafter also referred to as "tube pitch") can be set to be smaller than in an existing heat exchanger.Solution to Problem

[0006] A heat exchanger according to one embodiment of the present invention includes: a plurality of heat transfer tubes allowing a fluid to flow therethrough, and each having both ends in a tube axial direction that are sealed, the plurality of heat transfer tubes being arranged in a first direction crossing the tube axial direction; a tube pitch defining part configured to define a tube pitch of the plurality of heat transfer tubes in the first direction; and one or more headers penetrating the plurality of heat transfer tubes in the first direction to couple the plurality of heat transfer tubes together. Each of the plurality of heat transfer tubes has one or more header insertion holes into which the one or more headers are inserted, the one or more header insertion holes extending through the heat transfer tube in the first direction. Each of the one or more headers has a plurality of communication holes each causing the header to communicate with the inside of an associated one of the plurality of heat transfer tubes.

[0007] An air-conditioning apparatus according to another embodiment of the present invention includes a fluid circuit in which a compressor, the above heat exchanger, an expansion valve, and an indoor heat exchanger are connected by pipes, and the fluid circulates.Advantageous Effects of Invention

[0008] In the heat exchanger and the air-conditioning apparatus including the heat exchanger according to the embodiment of the present invention, the tube pitch of the plurality of heat transfer tubes in the first direction is defined by the tube pitch defining part, which is provided separate from the header. Each of the plurality of heat transfer tubes has the header insertion hole penetrating the heat transfer tube in the first direction. The header penetrates the plurality of heat transfer tubes in the first direction to couple the plurality of heat transfer tubes together. The header has the plurality of communication holes each of which causes the inside of the header to communicate with the inside of an associated one of the plurality of heat transfer tubes. Therefore, unlike an existing header, it is unnecessary to provide tube holes in the header, into which the end portions of the heat transfer tubes are inserted. In addition, a force for support of the heat transfer tube is not applied to the peripheral edge portion of the communication hole of the header. Accordingly, it is possible to reduce the interval between opening ports (the communication holes in the present invention) of the header and the tube pitch, as compared with an existing heat exchanger.Brief Description of Drawings

[0009] FIG. 1 is a perspective view illustrating an external appearance of a schematic configuration of a heat exchanger according to Embodiment 1. FIG. 2 is a schematic diagram illustrating a vertical section of an upper part of the heat exchanger as illustrated in FIG. 1. FIG. 3 is a vertical sectional view illustrating a vertical section A-A of the heat exchanger as illustrated in FIG. 2. FIG. 4 is an enlarged view of part of the heat exchanger as illustrated in FIG. 2 that is surrounded by a rectangle. FIG. 5 is a cross-sectional view illustrating a cross section B-B of the heat exchanger as illustrated in FIG. 4. FIG. 6 is a refrigerant circuit diagram of an air-conditioning apparatus in which the heat exchanger as illustrated in FIG. 1 is mounted. FIG. 7 is a vertical sectional view illustrating a first modification of a tube pitch defining part of the heat exchanger as illustrated in FIG. 2. FIG. 8 is a vertical sectional view illustrating a second modification of the tube pitch defining part of the heat exchanger as illustrated in FIG. 2. FIG. 9 is a vertical sectional view illustrating a first modification of a connection part between a heat transfer tube and a header of the heat exchanger as illustrated in FIG. 4. FIG. 10 is a vertical sectional view illustrating a second modification of the connection part between the heat transfer tube and the header of the heat exchanger illustrated in FIG. 4. FIG. 11 is a vertical sectional view illustrating a third modification of the connection part between the heat transfer tube and the header of the heat exchanger as illustrated in FIG. 4. FIG. 12 is a cross-sectional view illustrating a first modification of communication holes of the header of the heat exchanger as illustrated in FIG. 5. FIG. 13 is a cross-sectional view illustrating a second modification of the communication holes of the header of the heat exchanger illustrated in FIG. 5. FIG. 14 is a vertical sectional view illustrating a third modification of the communication holes of the header of the heat exchanger as illustrated in FIG. 5. FIG. 15 is vertical sectional view illustrating a first modification of a header of the heat exchanger as illustrated in FIG. 3. FIG. 16 is a vertical sectional view illustrating a second modification of the header of the heat exchanger as illustrated in FIG. 3. FIG. 17 is a perspective view schematically illustrating an external appearance of a first modification of the configuration of a flow passage in the heat exchanger illustrated in FIG. 1. FIG. 18 is a vertical sectional view of the heat exchanger as illustrated in FIG. 17. FIG. 19 is a partial vertical sectional view illustrating a section C-C of the heat exchanger as illustrated in FIG. 18. FIG. 20 is a perspective view schematically illustrating a second modification of the configuration of the flow passage in the heat exchanger as illustrated in FIG. 1. Description of Embodiments

[0010] Hereinafter, a heat exchanger according to Embodiment 1 will be described with reference to, for example, drawings. It should be noted that in figures including FIG. 1 that will be referred to below, for example, the relationships in dimension between components and the shapes of the components may differ from those of actual ones. Furthermore, in each of the figures, components that are the same as or equivalent to those in a previous figure or previous figures are denoted by the same reference signs, and the same is true of the entire text of the specification. In addition, in order that descriptions could be easily understood, terms indicating directions ("up", "down", "right", "left", "front", and "rear", for example) are used as appropriate; however, although these terms are used as a matter of convenience for explanation, they do not limit the arrangement of a device or devices or a component or components, or the orientation thereof. In the description, the positional relationships between the components, the extension directions of the components, and the arrangement directions of the components refer to, in principle, those in the case where the heat exchanger is installed in a usable state.Embodiment 1

[0011] FIG. 1 is a perspective view illustrating an external appearance of a schematic configuration of a heat exchanger 101 according to Embodiment 1. FIG. 2 is a schematic diagram of a vertical section of an upper part of the heat exchanger illustrated in FIG. 1. FIG. 3 is a vertical sectional view illustrating a vertical section A-A of the heat exchanger as illustrated in FIG. 2. FIG. 4 is an enlarged view of part of the heat exchanger as illustrated in FIG. 2 that is surrounded by a rectangle. FIG. 5 is a cross-sectional view illustrating a cross section B-B of the heat exchanger as illustrated in FIG. 4. The configuration of the heat exchanger 101 according to Embodiment 1 will be described with reference to FIGS. 1 to 5.

[0012] As illustrated in FIG. 1, the heat exchanger 101 includes a plurality of heat transfer tubes 10 and two headers (an upper header 61 and a lower header 62). The heat transfer tubes 10 are arranged in a first direction D1 crossing a tube axial direction. The two headers penetrate, in the first direction D1, end portions of the plurality of heat transfer tubes 10 on both sides in the tube axial direction. The heat exchanger 101 also includes tube pitch defining parts 20 that define a tube pitch Lp of the plurality of heat transfer tubes 10 in the first direction D1 (see FIG. 2). The heat exchanger 101 also includes a plurality of heat transfer fins 50.

[0013] Each of the heat transfer tubes 10 of the heat exchanger 101 is a flat tube that extends in a direction along a tube axis Ax (see FIG. 2) (that is, the tube axial direction), and that is shaped in such a manner as to be elongated in a single direction in cross section perpendicular to the tube axis Ax. Hereinafter, the first direction D1 in which the heat transfer tubes 10 are arranged may be referred to as "arrangement direction"; the tube axial direction of the heat transfer tube 10 may be referred to as "second direction D2" or "the longitudinal direction of the heat transfer tube 10", and the longitudinal direction of the cross section of the heat transfer tube 10 may be referred to as "third direction D3" or "the width direction of the heat transfer tube 10".

[0014] In addition, in the following description, it is defined that the heat exchanger 101 is installed such that the arrangement direction of the heat transfer tubes 10 (the first direction D1) coincides with the lateral direction. It is also defined that the heat transfer tubes 10 are arranged such that the tube axes Ax of the heat transfer tubes 10 coincide with the up-down direction orthogonal to the arrangement direction (the first direction D1), and such that the width direction of the heat transfer tubes 10 (the third direction D3) coincides with the front-back direction orthogonal to the tube axial direction and the arrangement direction.

[0015] The arrangement of the heat exchanger 101 or the angle between the arrangement direction of the heat transfer tubes 10 of the heat exchanger 101 (the first direction D1) and the tube axial direction of each heat transfer tube 10 (the second direction D2) are not limited to those described above. For example, the heat exchanger 101 may be inclined such that the tube axial direction of the heat transfer tube 10 is inclined relative to the up-down direction. Alternatively, the heat exchanger 101 may be configured such that the tube axial direction of the heat transfer tube 10 is inclined relative to the up-down direction in the case where the heat exchanger 101 is installed such that the arrangement direction of the heat transfer tubes 10 (the first direction D1) coincides with the lateral direction.

[0016] As illustrated in FIGS. 2 and 5, spaces are provided as air flow passages P2, between tube walls 11 of the heat transfer tubes 10 disposed adjacent to each other in the arrangement direction (the first direction D1), and air flows through the spaces in the heat exchanger 101 along the width direction of the heat transfer tubes 10 (the third direction D3).

[0017] Referring to FIG. 1, a first pipe a and a second pipe b are provided at right ends of the upper header 61 and the lower header 62, respectively, and each form an inlet / outlet of the heat exchanger 101 for a fluid (for example, refrigerant). It should be noted that the fluid flowing through the heat transfer tubes 10 may be refrigerant, or may be water, brine, or other kinds of fluid. Fluid flow passages are provided between the first pipe a and the second pipe b in the heat exchanger 101. To be more specific, as illustrated in FIG. 2, the inner spaces of the heat transfer tubes 10 and the inner spaces of the upper header 61 and the lower header 62 form the fluid flow passages. The heat exchanger 101 causes heat exchange to be performed between air and fluid. The following description is made on the assumption that a fluid flowing through the plurality of heat transfer tubes 10 is refrigerant.

[0018] As illustrated in FIG. 1, at the upper end portion of each of the heat transfer tubes 10, a header insertion hole 10h1 that allows the upper header 61 to be inserted thereinto is formed to extend through the upper end portion of the heat transfer tube 10 in the first direction D1. At the lower end portion of the heat transfer tube 10, a header insertion hole 10h2 that allows the lower header 62 to be inserted thereinto is formed to extend through the lower end of the heat transfer tube 10 in the first direction D1. The heat transfer tube 10 has a tube structure in which an inner space through which the refrigerant flows is provided in the longitudinal direction of the heat transfer tube 10 (the second direction D2), that is, from the upper end to the lower end of the tube wall 11. Opening ends 10e of the heat transfer tubes 10 on both sides in the longitudinal direction are sealed. A sealing structure will be described later.

[0019] As illustrated in FIGS. 2 and 5, the tube wall 11 of the heat transfer tube 10 includes a first tube-side wall part 10a, a second tube-side wall part 10b, and connecting wall parts 10c and 10d. The first tube-side wall part 10a and the second tube-side wall part 10b face each other in the first direction D1 and are formed in the shape of a substantially flat plate, and the connecting wall parts 10c and 10d are formed in the shape of a curved surface and connect the first tube-side wall part 10a and the second tube-side wall part 10b together at end portions of the first tube-side wall part 10a and the second tube-side wall part 10b on both sides in the third direction D3. As illustrated in FIGS. 2 and 3, each of the first tube-side wall part 10a and the second tube-side wall part 10b has a rectangular shape in which the long sides extend in the longitudinal direction of the heat transfer tube 10 (the second direction D2), and the short sides extend in the width direction of the heat transfer tube 10 (the third direction D3).

[0020] Although each of the first tube-side wall parts 10a and 10b has a flat plate shape, "flat plate shape" is not necessarily a completely flat surface, and it suffices that "flat plate shape" be a structure that appears as a whole to flatly spread. For example, part of a region that flatly spreads may have a recess, a protrusion, or a corrugation. Referring to FIG. 2, the left wall part of the tube wall 11 is the first tube-side wall part 10a, and the right wall part of the tube wall 11 is the second tube-side wall part 10b.

[0021] As illustrated in FIG. 2, the first tube-side wall part 10a on the left side has a first hole ha that extends through the first tube-side wall part 10a in the first direction D1, and the second tube-side wall part 10b on the right side has a second hole hb that extends through the second tube-side wall part 10b in the first direction D1. The header insertion hole 10h1 includes the first hole ha and the second hole hb. The first hole ha and the second hole hb have a circular shape, for example (see FIG. 3). The configuration of the header insertion hole 10h2 into which the lower header 62 is inserted, is similar to that of the above header insertion hole 10h1 into which the upper header 61 is inserted, and the header insertion hole 10h2 includes a first hole ha formed in the first tube-side wall part 10a and a second hole hb formed in the second tube-side wall part 10b.

[0022] As illustrated in FIG. 1, the header insertion holes 10h1 and 10h2 are provided inward of the opening ends 10e of the heat transfer tubes 10 on both sides in the longitudinal direction (the second direction D2). In the heat exchanger 101 disposed as illustrated in FIG. 1, the header insertion holes 10h1 of the heat transfer tubes 10 are provided below the opening ends 10e of the heat transfer tubes 10 on the upper side, and the header insertion holes 10h2 of the heat transfer tubes 10 are provided above the opening ends 10e of the heat transfer tubes 10 on the lower side.

[0023] As illustrated in FIG. 1, each of the upper header 61 and the lower header 62 penetrates the heat transfer tubes 10 to couple the heat transfer tubes 10 together. The upper header 61 and the lower header 62 have a cylindrical shape, for example. Referring to FIG. 1, the left end of each of the upper header 61 and the lower header 62 does not form a refrigerant inlet / outlet, and is sealed.

[0024] As illustrated in FIG. 4, the upper header 61 has a plurality of communication holes 60h through which the inner space of the upper header 61 and the inner spaces of the heat transfer tubes 10 communicate with each other. The communication holes 60h are formed in the upper header 61 at intervals Lh equal to the tube pitch Lp of the heat transfer tubes 10 in the first direction D1. Although it is not illustrated, the lower header 62 as illustrated in FIG. 1 also has a plurality of communication holes 60h through which the inner space of the lower header 62 and the inner spaces of the heat transfer tubes 10 communicate with each other.

[0025] That is, the refrigerant flow passages of the heat exchanger 101 include heat transfer passages P1a and header flow passages P1h. The heat transfer passages P1a are provided in the tube walls 11 of the heat transfer tubes 10, and extend in the longitudinal direction of the heat transfer tubes 10 (the second direction D2). The header flow passages P1h are provided in the upper header 61 and the lower header 62, extend in the arrangement direction of the heat transfer tubes 10 (the first direction D1), and cause the heat transfer passages P1a of the heat transfer tubes 10 to communicate with each other.

[0026] In an example illustrated in FIGS. 4 and 5, the communication holes 60h are provided in the lower end portion of the upper header 61 in the circumferential direction, the upper header 61 extending in the first direction D1. The communication holes 60h have a circular shape, for example (see FIG. 5). In the example illustrated in FIGS. 4 and 5, the communication holes 60h are provided in the respective heat transfer tubes 10 such that the central line of each of the communication holes 60h coincides with the center line of an associated one of the heat transfer tubes 10 in the first direction D1.

[0027] In addition, the communication hole 60h is provided such that in the first direction D1, the width of the communication holes 60h, that is, the diameter of the communication hole 60h is nearly equal to a width W of the heat transfer passage P1a of the heat transfer tube 10, that is, the distance between the first tube-side wall part 10a and the second tube-side wall part 10b. The structure of the lower part of the heat exchanger 101 is substantially the same as a structure that is obtained by vertically inverting the upper part of the heat exchanger 101. In the lower header 62, the communication holes 60h are provided in the upper end portion of the lower header 62 in the circumferential direction. The positions, number, and shape of the communication holes 60h of each header (the upper header 61 and the lower header 62) are not limited to those described above. Other configuration examples of the communication holes 60h of each header will be described later.

[0028] As illustrated in FIG. 1, each of the tube pitch defining parts 20 is formed of a plate-like member that covers the opening ends 10e of the heat transfer tubes 10 and that has a substantially rectangular shape as viewed in plan view. In the heat exchanger 101 as illustrated in FIG. 1, the tube pitch defining parts 20 are disposed at two locations, that is, at the upper side and the lower side of the heat transfer tubes 10.

[0029] More specifically, as illustrated in FIG. 2, the tube pitch defining part 20 includes a plurality of groove parts 22 (hereinafter also referred to as "engagement parts") and flat connection parts 21 (hereinafter also referred to as "connection parts") disposed between the groove parts 22. In the tube pitch defining part 20, the groove parts 22 are formed at a constant pitch Lr in the arrangement direction of the heat transfer tubes 10 (the first direction D1), and extend in the width direction of the heat transfer tube 10 (the third direction D3) along the opening ends 10e of the heat transfer tubes 10 (see FIG. 1).

[0030] The pitch Lr of the groove parts 22 of the tube pitch defining part 20 is equal to the tube pitch Lp of the heat transfer tubes 10. The end portions of the heat transfer tubes 10, which include the opening ends 10e, are disposed in the respective groove parts 22 of the tube pitch defining part 20. The width of each groove part 22 in the first direction D1 is substantially equal to or slightly greater than the thickness of each heat transfer tube 10 in the first direction D1.

[0031] In the case where the heat transfer tubes 10 are provided apart from each other at the time of manufacturing the heat exchanger 101, the end portions of the heat transfer tubes 10 in the longitudinal direction are inserted into the respective groove parts 22 of the tube pitch defining parts 20. As a result, the heat transfer tubes 10 are arranged at the constant tube pitch Lp in the first direction D1. Since the tube pitch defining parts 20 cause the heat transfer tubes 10 to be arranged at the constant tube pitch Lp in the first direction D1, in a step of assembling the upper header 61 and the heat transfer tubes 10 or in a step of assembling the upper header 61 and the plurality of heat transfer tubes 10, it is not necessary to adjust the positions of the heat transfer tubes 10 in units of one heat transfer tube 10.

[0032] Accordingly, it is possible to easily perform positioning between the heat transfer tubes 10 and the communication holes 60h of each header (the upper header 61, the lower header 62). The tube pitch defining parts 20 are joined to the opening ends 10e of the heat transfer tubes 10 by joining means, such as brazing or adhesive agent. An outer peripheral surface of each header (the upper header 61, the lower header 62) is joined to the inner peripheral surfaces of the header insertion holes 10h1 and 10h2 of the heat transfer tubes 10 by joining means, such as brazing or adhesive agent.

[0033] By providing the tube pitch defining parts 20, which cover the opening ends 10e of the heat transfer tubes 10, on both sides of the heat transfer tubes 10 in the longitudinal direction (the second direction D2) as illustrated in FIG. 1, the opening ends 10e of the heat transfer tubes 10 on both sides in the longitudinal direction are sealed. That is, each of the two tube pitch defining parts 20 also serves as a common tube sealing structure for the heat transfer tubes 10.

[0034] In the tube pitch defining part 20 on the lower side, it is preferable that the flat connection parts 21, which are portions other than portions that close the opening ends 10e of the heat transfer tubes 10 on the lower side (that is, the groove parts 22), have drain holes for discharging water, such as condensation water or meltwater from frost, generated in, for example, the heat transfer tubes 10.

[0035] It suffices that the tube pitch defining part 20 is provided at one end (the opening ends 10e) of the plurality of heat transfer tubes 10 in the longitudinal direction (the second direction D2). In this case, it suffices that the other end of the plurality of heat transfer tubes 10 in the longitudinal direction (the second direction D2) is sealed by tube sealing parts 70 that individually seal the opening ends 10e (see FIG. 8 that will be referred to later).

[0036] The configuration of the tube pitch defining part 20 is not limited to the above configuration. However, in the case where the above configuration, that is, the configuration in which the end portions of the heat transfer tubes 10 are inserted into the groove parts 22 is adopted, the movement of the heat transfer tubes 10 in the first direction D1 can be reduced by both side surfaces of the groove parts 22, and the configuration is thus advantageous in terms of the function of defining the tube pitch Lp and strength. Other configuration examples of the tube pitch defining parts 20 will be described later.

[0037] The heat exchanger 101 as illustrated in FIG. 1 includes, as an example of the heat transfer fins 50, corrugated fins in respective spaces between the heat transfer tubes 10, that is, in the air flow passages P2. Each of the corrugated fins connects the first tube-side wall part 10a and the second tube-side wall part 10b of associated adjacent ones of the heat transfer tubes 10, the first tube-side wall part 10a and the second tube-side wall part 10b facing each other. In this case, the first tube-side wall part 10a and the second tube-side wall part 10b of the adjacent heat transfer tubes 10 are joined to the heat transfer fins 50 by brazing, the first tube-side wall part 10a and the second tube-side wall part 10b facing each other. Since the heat exchanger 101 includes the heat transfer fins 50, heat exchange between refrigerant and air is promoted, and the heat exchange performance of the heat exchanger 101 is improved.

[0038] FIG. 6 is a refrigerant circuit diagram of an air-conditioning apparatus 100 in which the heat exchanger 101 as illustrated in FIG. 1 is mounted. As illustrated in FIG. 6, the heat exchanger 101 forms part of a refrigerant circuit 100c of the air-conditioning apparatus 100, in which the refrigerant circulates.

[0039] The air-conditioning apparatus 100 includes a compressor 102, the heat exchanger 101, an expansion valve 105, an indoor heat exchanger 104, and a four-way valve 103. Referring to FIG. 6, the compressor 102, the heat exchanger 101, the expansion valve 105, and the four-way valve 103 are provided in an outdoor unit 100A, and the indoor heat exchanger 104 is provided in an indoor unit 100B. The first pipe a and the second pipe b (see FIG. 1), each of which forms the refrigerant inlet / outlet of the heat exchanger 101, are connected to the four-way valve 103 and the expansion valve 105 of the refrigerant circuit 100c.

[0040] The compressor 102, the heat exchanger 101, the expansion valve 105, the indoor heat exchanger 104, and the four-way valve 103 are connected by refrigerant pipes (also simply referred to as "pipes"), thereby forming the refrigerant circuit 100c in which the refrigerant can be circulated. In the air-conditioning apparatus 100, when the compressor 102 is operated, a refrigeration cycle is performed in which the refrigerant circulates through the compressor 102, the heat exchanger 101, the expansion valve 105, and the indoor heat exchanger 104, while changing in phase.

[0041] The outdoor unit 100A is provided with an outdoor fan 107 that forcibly causes outdoor air to pass through the heat exchanger 101. The heat exchanger 101 causes heat exchange to be performed between the refrigerant and outdoor air flow generated by operation of the outdoor fan 107. The indoor unit 100B is provided with an indoor fan 106 that forcibly causes indoor air to pass through the indoor heat exchanger 104. The indoor heat exchanger 104 causes heat exchange to be performed between the refrigerant and an indoor air flow generated by operation of the indoor fan 106.

[0042] The operation of the air-conditioning apparatus 100 can be switched between a cooling operation and a heating operation. In FIG. 6, the flow direction of the refrigerant in the cooling operation is indicated by dashed arrows, and the flow direction of the refrigerant in the heating operation is indicated by solid arrows. The four-way valve 103 is a solenoid valve that switches the refrigerant flow passage between multiple refrigerant flow passages to switch the operation between the cooling operation and the heating operation of the air-conditioning apparatus 100.

[0043] Instead of the four-way valve 103, a two-way valve and a three-way valve may be used in combination to switch the refrigerant flow passage. In the cooling operation, the four-way valve 103 guides refrigerant from the compressor 102 to the heat exchanger 101, and guides refrigerant from the indoor heat exchanger 104 to the compressor 102. In the heating operation, the four-way valve 103 guides refrigerant from the compressor 102 to the indoor heat exchanger 104, and guides refrigerant from the heat exchanger 101 to the compressor 102.

[0044] In the cooling operation of the air-conditioning apparatus 100, refrigerant compressed by the compressor 102 is sent to the heat exchanger 101. In the heat exchanger 101, the refrigerant is condensed by transferring heat to outdoor air. Then, the refrigerant is sent to the expansion valve 105, is reduced in pressure by the expansion valve 105, and is then sent to the indoor heat exchanger 104. Thereafter, the refrigerant is evaporated by receiving heat from indoor air in the indoor heat exchanger 104, and then returns to the compressor 102. Therefore, in the cooling operation of the air-conditioning apparatus 100, the heat exchanger 101 serves as a condenser, and the indoor heat exchanger 104 serves as an evaporator.

[0045] In the heating operation of the air-conditioning apparatus 100, refrigerant compressed by the compressor 102 is sent to the indoor heat exchanger 104. In the indoor heat exchanger 104, the refrigerant is condensed by transferring heat to indoor air. Then, the refrigerant is sent to the expansion valve 105, is reduced in pressure by the expansion valve 105, and is then sent to the heat exchanger 101. Thereafter, the refrigerant is evaporated by receiving heat from outdoor air in the heat exchanger 101, and then returns to the compressor 102. Therefore, in the heating operation of the air-conditioning apparatus 100, the heat exchanger 101 serves as an evaporator, and the indoor heat exchanger 104 serves as a condenser.

[0046] Next, an example of the operation of the heat exchanger 101 will be described with reference to FIGS. 1, 2, and 6. As indicated by an outlined arrow in FIG. 1, the refrigerant flows into the heat exchanger 101 through the first pipe a. As illustrated in FIG. 2, in the heat exchanger 101, the refrigerant first flows into the header flow passage P1h of the upper header 61, and flows through the header flow passage P1h from right to left. In this process, the refrigerant is distributed to the heat transfer tubes 10 from the communication holes 60h provided in the upper header 61, and flows into the heat transfer passages P1a of the heat transfer tubes 10. In the heat transfer passages P1a, the refrigerant flows downward.

[0047] At this time, the refrigerant exchanges heat, via the tube walls 11, with air that flows through the spaces (that is, the air flow passages P2) provided between the tube walls 11 of the heat transfer tubes 10. The refrigerant from the heat transfer passages P1a flows into the header flow passage P1h of the lower header 62, which penetrates the lower end portions of the heat transfer tubes 10, through the communication holes 60h, and merges together in the header flow passage P1h. The refrigerant that has merged together in the header flow passage P1h flows out to the outside of the heat exchanger 101 (for example, the expansion valve 105 of the refrigerant circuit 100c as illustrated in FIG. 6) from the second pipe b provided at the right end of the lower header 62.

[0048] FIG. 7 is a vertical sectional view illustrating a first modification of the tube pitch defining part of the heat exchanger 101 as illustrated in FIG. 2. As illustrated in FIG. 7, although a tube pitch defining part 120 according to the first modification is formed of a plate-like member having a substantially rectangular shape as viewed in plan view in the same manner as in the example illustrated in FIG. 2, portions that are engaged with and joined to the end portions of the respective heat transfer tubes 10 (that is, engagement parts) are not the groove parts 22, but are protruding parts 122.

[0049] The protruding parts 122 extend in the third direction D3 and are provided on one surface of the tube pitch defining part 120 at a constant pitch Lr1 in the first direction D1. The protruding parts 122 are inserted into the end portions of the heat transfer tubes 10, thereby closing the opening ends 10e, and the tube pitch defining part 120 causes the heat transfer tubes 10 to be arranged at the constant tube pitch Lp (that is, the pitch Lr1). The tube pitch defining part 120 is joined to the end portions of the heat transfer tubes 10 by joining means, such as brazing or an adhesive agent.

[0050] In the heat exchanger 101 as illustrated in FIG. 7, the surfaces of the tube walls 11 of the heat transfer tubes 10 from one end to the other end in the tube axial direction (the second direction D2) are exposed to the air flow passages P2, and the heat exchanger 101 as illustrated in FIG. 7 has a larger heat exchange area than in the configuration as illustrated in FIG. 2, in which the end portions of the heat transfer tubes 10 are inserted into the groove parts 22.

[0051] FIG. 8 is a vertical sectional view illustrating a second modification of the tube pitch defining part of the heat exchanger 101 as illustrated in FIG. 2. As illustrated in FIG. 8, tube pitch defining parts 220 according to the second modification are provided at the tube walls 11 of heat transfer tubes 210. That is, in the heat exchanger 101 as illustrated in FIG. 8, tube sealing parts 70 that close opening ends 10e of the heat transfer tubes 210 are provided, in addition to the tube pitch defining parts 220 that define a tube pitch Lp of the heat transfer tubes 210.

[0052] The tube pitch defining parts 220 are protrusion parts that protrude outward from the tube walls 11 of the heat transfer tubes 210. To be more specific, each of the tube pitch defining parts 220 is configured such that a first protrusion part 221 protruding toward the left side is provided at the first tube-side wall part 10a on the left side, and a second protrusion part 222 protruding toward the right side is provided at the second tube-side wall part 10b on the right side, the first tube-side wall part 10a and the second tube-side wall part 10b of the tube wall 11 facing each other in the lateral direction (the first direction D1), and having a substantially flat plate shape. A distal end of the first protrusion part 221 and a distal end of the second protrusion part 222 of any adjacent ones of the heat transfer tubes 210 contact each other, thereby defining the distance between the tube walls 11 of the adjacent heat transfer tubes 210. In other words, the tube pitch defining parts 220 according to the second modification are spacers provided at the tube walls 11 of the heat transfer tubes 210.

[0053] As illustrated in FIG. 8, each of the first protrusion part 221 and the second protrusion part 222 is formed in the shape of, for example, a quadrangular frame as the heat exchanger 101 is viewed from the front side. The shape of each of the first protrusion part 221 and the second protrusion part 222 is not limited to the above shape, and may be, for example, a trapezoidal frame shape or a triangular frame shape. Since each of the tube pitch defining parts 220 includes the first protrusion part 221 and the second protrusion part 222 provided at an associated one of the heat transfer tubes 210, the heat transfer area of the heat exchanger 101 is increased, thereby improving the heat exchange performance. It should be noted that the first protrusion part 221 and the second protrusion part 222 are each made to have a frame shape in order to reduce airflow resistance.

[0054] In the example illustrated in FIG. 8, two protrusion parts, that is, the first protrusion part 221 and the second protrusion part 222, are provided at each heat transfer tube 210. However, one protrusion part having a greater length may be provided at each heat transfer tube 210, and contact the tube wall 11 of an adjacent heat transfer tube 210.

[0055] As illustrated in FIG. 8, each of the tube pitch defining parts 220 can be provided integrally with an associated one of the heat transfer tubes 210. To be more specific, part of material that forms the heat transfer tube 210 is provided as the tube pitch defining part 220. For example, in the case where the heat transfer tube 210 is formed of a plate-like material, it suffices that the first protrusion part 221 and the second protrusion part 222 are formed as follows: the heat transfer tube 210 is formed of material that has margin portions in addition to a portion that forms the tube wall 11; in this formation, cuts are made in the margin portions at the same time as the header insertion holes 10h1 and 10h2 and other parts are formed; and the margin portions are then bent, for example.

[0056] It should be noted that the first protrusion part 221 and the second protrusion part 222 may be formed of material other than material of which the heat transfer tube 210 is formed.

[0057] The tube sealing parts 70 are provided for the respective heat transfer tubes 210 to seal the respective opening ends 10e. Referring to FIG. 8, the tube sealing part 70 is provided in such a manner as to cover the end surface of the heat transfer tube 210, and is joined to close the opening end 10e. It should be noted that the configuration of the tube sealing part 70 is not limited to the above configuration. For example, the tube sealing part 70 may include a protruding part that is inserted into the end portion of the heat transfer tube 210, or may be formed by processing the opening end 10e itself of the heat transfer tube 10.

[0058] FIG. 9 is a vertical sectional view illustrating a first modification of connection part between the heat transfer tube 10 and the header of the heat exchanger 101 as illustrated in FIG. 4. At the peripheral edge portion of the header insertion hole 10h1 of each of the heat transfer tubes 10, a peripheral edge protruding part 12 is formed to extend in the first direction D1. Although it is not illustrated, the peripheral edge protruding part 12 extending in the first direction D1 is also provided at the peripheral edge portion of the header insertion hole 10h2 of the heat transfer tube 10, as at the peripheral edge portion of the header insertion hole 10h1.

[0059] To be more specific, the peripheral edge protruding part 12 includes a first peripheral edge protruding part 12a and a second peripheral edge protruding part 12b. The first peripheral edge protruding part 12a is formed at a peripheral edge portion of the first hole ha of the first tube-side wall part 10a on the left side, and the second peripheral edge protruding part 12b is formed at a peripheral edge portion of the second hole hb of the second tube-side wall part 10b on the right side.

[0060] The first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b are provided to extend in opposite directions in such a manner as to protrude outward from the tube wall 11 of the heat transfer tube 10. That is, the first peripheral edge protruding part 12a extends toward the left side from the first tube-side wall part 10a on the left side, and the second peripheral edge protruding part 12b extends toward the right side from the second tube-side wall part 10b on the right side.

[0061] In the first direction D1, each of the communication holes 60h of each of the headers (the upper header 61 and the lower header 62) is disposed between the distal ends of the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b of one of the heat transfer tubes 10 that communicates with the above communication hole 60h.

[0062] In the case where a width Wh of the communication hole 60h is set to be substantially equal to the width W of the heat transfer passage P1a of the heat transfer tube 10 in the first direction D1, there is a risk that leakage of refrigerant will occur when the communication hole 60h is displaced relative to the heat transfer tube 10 in the first direction D1. With the configuration as illustrated in FIG. 9 in which the peripheral edge protruding part 12 protruding outward is provided at the peripheral edge portion of each of the header insertion holes 10h1 and 10h2, even when the communication hole 60h of the header is slightly displaced relative to the heat transfer tube 10 in the first direction D1, occurrence of leakage of refrigerant can be reduced by the peripheral edge protruding part 12 extending outward from the tube wall 11, as compared with the configuration as illustrated in FIG. 5 in which the peripheral edge protruding part 12 is not provided at the peripheral edge portion of each of the header insertion holes 10h1 and 10h2.

[0063] Such a heat transfer tube 10 as described above may be manufactured as follows: for example, the first hole ha, the second hole hb, the first peripheral edge protruding part 12a, and the second peripheral edge protruding part 12b of each of the header insertion hole 10h1 and the header insertion hole 10h2 are formed in advance at material to be formed into the heat transfer tube 10, and this part is then formed into the heat transfer tube 10 by roll forming. The first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b may be formed by raising the peripheral edge portions of the first hole ha and the second hole hb when the first hole ha and the second hole hb are formed in the part to be formed into the heat transfer tube 10, and for example, the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b may be formed by burring processing. The method for forming the heat transfer tube 10 is not limited to roll forming, and the heat transfer tube 10 may be formed by, for example, extrusion or drawing.

[0064] FIG. 10 is a vertical sectional view illustrating a second modification of the connection part between the heat transfer tube 10 and the header of the heat exchanger 101 as illustrated in FIG. 4. In the example illustrated in FIG. 10, the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b are provided to extend toward the same side in the first direction D1 from the tube wall 11 of the heat transfer tube 10. Referring to FIG. 10, the first peripheral edge protruding part 12a extends toward the left side from the first tube-side wall part 10a on the left side, and the second peripheral edge protruding part 12b extends toward the left side from the second tube-side wall part 10b on the right side.

[0065] In the first direction D1, each of the communication holes 60h of each of the headers (the upper header 61 and the lower header 62) is disposed between the distal end of the first peripheral edge protruding part 12a and the outer surface of the second tube-side wall part 10b of an associated one of the heat transfer tubes 10 that communicates with the communication hole 60h.

[0066] With the configuration as illustrated in FIG. 10 in which the peripheral edge protruding part 12 extending toward one side (the left side in FIG. 10) in the first direction D1 is provided at the peripheral edge portion of each of the header insertion holes 10h1 and 10h2, even when the communication holes 60h of the header are slightly displaced relative to the heat transfer tubes 10 toward the one side (left side) in the first direction, occurrence of leakage of refrigerant can be reduced by the first peripheral edge protruding parts 12a extending from the tube walls 11, as compared with the configuration as illustrated in FIG. 5 in which the peripheral edge protruding part 12 is not provided at the peripheral edge portion of each of the header insertion hole 10h1, 10h2.

[0067] FIG. 11 is a vertical sectional view illustrating a third modification of the connection part between the heat transfer tube 10 and the header of the heat exchanger 101 as illustrated in FIG. 4. In the example illustrated in FIG. 11, the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b are provided to extend in opposite directions in such a manner as to protrude outward from the tube wall 11 of the heat transfer tube 10, and the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b include inclined tapered portions 12at and 12bt, respectively, at their proximal ends. Distal end portions 12ae and 12be of the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b extend in the first direction D1 along the outer peripheral surface of the header. The distal end portions 12ae and 12be are joined to the outer peripheral surface of the header.

[0068] The tapered portion 12at of the first peripheral edge protruding part 12a is an annular part whose opening diameter decreases in a direction from the first tube-side wall part 10a toward the distal end portion 12ae on the left side. The tapered portion 12bt of the second peripheral edge protruding part 12b is an annular part whose opening diameter decreases in the direction from the second tube-side wall part 10b toward the distal end portion 12be on the right side. That is, each of the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b is shaped such that the proximal end is more bulged than the distal end portion 12ae and 12be joined to the outer peripheral surface of the header.

[0069] As described above, in the example illustrated in FIG. 11, the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b include the tapered portions 12at and 12bt, respectively. Thus, in the first direction D1, the width Wh of each of the communication holes 60h of the header can be made greater than the width W of the heat transfer passage P1a of the heat transfer tube 10, that is, the distance between the first tube-side wall part 10a and the second tube-side wall part 10b.

[0070] Hereinafter, other configuration examples of the communication holes 60h of the header will be described. FIG. 12 is a cross sectional view illustrating a first modification of the communication holes 60h of the header of the heat exchanger 101 as illustrated in FIG. 5. In the example illustrated in FIG. 5, the communication holes 60h are provided in each of the headers (the upper header 61 and the lower header 62) such that one communication hole 60h is provided for one heat transfer tube 10.

[0071] However, in the example illustrated in FIG. 12, the communication holes 60h are provided in each header such that two communication holes 60h are provided for one heat transfer tube 10; to be more specific, two communication holes 60h are provided in the peripheral wall portion of the lower half of the upper header 61 and located respectively rearward and forward of the tube axis Ax of the heat transfer tube 10, and two communication holes 60h are also provided in the peripheral wall portion of the upper half of the lower header 62 and located respectively rearward and forward of the tube axis Ax of the heat transfer tube 10. The communication holes 60h may be provided in each header such that three communication holes 60h are provided for one heat transfer tube 10.

[0072] FIG. 13 is a cross sectional view illustrating a second modification of the communication holes 60h of the header of the heat exchanger 101 as illustrated in FIG. 5. In the example illustrated in FIG. 5, the communication holes 60h have a circular shape. However, in the example illustrated in FIG. 13, the communication holes 60h are formed in the shape of slits extending in the third direction D3. In such a manner, since the communication holes 60h extend in the third direction D3, the communication holes 60h are formed to extend in the longitudinal direction of the cross section of the heat transfer tube 10, whereby it is possible to reduce maldistribution of refrigerant in the third direction D3 that flows into the heat transfer passage P1a of the heat transfer tube 10 from the header flow passage P1h.

[0073] FIG. 14 is a vertical sectional view illustrating a third modification of the communication holes 60h of the header of the heat exchanger 101 as illustrated in FIG. 5. In the example illustrated in FIG. 5, the communication holes 60h are provided in the lower end portion of the upper header 61. However, in the example illustrated in FIG. 14, each communication hole 60h is provided within a predetermined angle range in the circumferential direction of the upper header 61 such that the communication hole 60h is located in the vicinity of the liquid surface of the refrigerant in the upper header 61. Hereinafter, one example of the angle range of the communication hole 60h will be described, and it is assumed that the heat exchanger 101 is provided such that the tube axial direction of each heat transfer tube 10 coincides with the vertical direction.

[0074] In the following description, an angle Φ of the communication hole 60h is an angle from the lower end on a vertical line passing through the center Ch of a header peripheral wall to the position of the communication hole 60h, as viewed from the center Ch. That is, the position of the communication hole 60h in the circumferential direction is represented by the angle Φ on the assumption that the vertically downward direction from the center Ch is 0 degrees. The communication hole 60h is provided such that the angle Φ of the communication hole 60h satisfies ΦDo < Φ < ΦDs, where ΦDo is the angle of the liquid surface on the assumptions that the slip ratio between gas and liquid of refrigerant is 1, and that the gas-liquid interface is flat and horizontal, and ΦDs is the angle of the liquid surface of the refrigerant in the header pipe. Then, where As [mm 2< ] is the cross-sectional area of the flow passage in the header flow passage P1h, ΦDo is expressed by (-0.0408 × As + 74.124) × 0.62, and ΦDs is expressed by (-0.0408 × As + 74.124) × 1.2.

[0075] In the example illustrated in FIG. 1, it is defined that the heat exchanger 101 includes two headers (the upper header 61 and the lower header 62), the upper header 61 penetrates the upper end portions of the heat transfer tubes 10, and the lower header 62 penetrates the lower end portions of the heat transfer tubes 10. However, the heat exchanger 101 may include only one header. Alternatively, both of two headers may be arranged in the front-back direction to penetrate end portions of the heat transfer tubes 10 on one side in the tube axial direction. The heat exchanger 101 may include three or more headers.

[0076] FIG. 15 is a vertical sectional view illustrating a first modification of the header of the heat exchanger 101 as illustrated in FIG. 3. As illustrated in FIG. 15, an upper header 161 includes three small-diameter headers 161a, 161b, and 161c that penetrate the heat transfer tubes 10 in the first direction D1 and that are arranged in each of the heat transfer tubes 10 in the direction (the third direction D3) orthogonal to the tube axial direction (the second direction D2) and the first direction D1. Each of the small-diameter headers 161a, 161b, and 161c has a cylindrical shape, and an outer diameter W2 of each of the small-diameter headers 161a, 161b, and 161c is smaller than an outer diameter W1 of the upper header 61 as illustrated in FIG. 3.

[0077] Furthermore, three header insertion holes 10h1a, 10h1b, and 10h1c having a circular shape are formed in each heat transfer tube 10, and allow the three small-diameter headers 161a, 161b, and 161c to be inserted into the three header insertion holes 10h1a, 10h1b, and 10h1c, respectively. The number of small-diameter headers 161a, 161b, and 161c arranged in the third direction D3 is not limited to three, and may be two or four or more.

[0078] As described above, since the header (the upper header 161) includes the small-diameter headers 161a, 161b, and 161c, the opening diameter of the header insertion holes 10h1a, 10h1b, and 10h1c is smaller than in the case illustrated in FIG. 3 in which the header includes one header pipe (the upper header 61). Therefore, a heat transfer area is increased in the longitudinal direction of the heat transfer tube 10 (the second direction D2), and the heat exchange performance of the heat exchanger 101 is thus improved. In addition, since the header (the upper header 161) includes the small-diameter headers 161a, 161b, and 161c, the maldistribution of liquid is reduced, and a more satisfactory distribution is achieved, thus improving the heat exchange performance.

[0079] FIG. 16 is a vertical-sectional view illustrating a second modification of the header of the heat exchanger 101 as illustrated in FIG. 3. As illustrated in FIG. 16, the upper header includes an elliptical header 261 that has an elliptical cross section perpendicular to the first direction D1. Referring to FIG. 16, the elliptical header 261 has an elliptical shape in cross section. The elliptical header 261 penetrates the heat transfer tubes 10 such that the longitudinal direction of the cross section of the elliptical header 261 coincides with the direction (the third direction D3) orthogonal to the tube axial direction and the first direction D1 in each of the heat transfer tubes 10. In the longitudinal direction of the heat transfer tube 10 (the second direction D2), an outer diameter W3 of the elliptical header 261 is smaller than the outer diameter W1 of the upper header 61 as illustrated in FIG. 3.

[0080] In such a manner, since the header (upper header) is the elliptical header 261, the opening width of the header insertion hole 10h1 in the second direction D2 can be set to be smaller than in the case illustrated in FIG. 3 in which the header includes one header pipe (the upper header 61). Therefore, in the case illustrated in FIG. 16, as in the case illustrated in FIG. 15, the heat transfer area is increased in the longitudinal direction of the heat transfer tube 10 (the second direction D2), and the heat exchange performance of the heat exchanger 101 is improved.

[0081] FIG. 17 is a perspective view schematically illustrating an external appearance of a first modification of the configuration of the flow passage in the heat exchanger 101 as illustrated in FIG. 1. FIG. 18 is a vertical-sectional view of the heat exchanger 101 as illustrated in FIG. 17. FIG. 19 is a partial vertical-sectional view illustrating a section C-C of the heat exchanger 101 as illustrated in FIG. 18. As illustrated in FIGS. 17 to 19, by changing the arrangement of two headers, it is possible to form a refrigerant flow passage that is different from the refrigerant flow passage as illustrated in FIG. 1.

[0082] In the heat exchanger 101 as illustrated in FIGS. 17 to 19, two headers (a first header 361 and a second header 362) are arranged in the front-back direction at the lower part of the heat exchanger 101. Referring to FIG. 17, the first header 361 provided with the first pipe a is disposed on the rear side, and the second header 362 provided with the second pipe b is disposed on the front side. Both the first pipe a and the second pipe b are provided at a lower left portion of the heat exchanger 101. The communication holes 60h are provided in, for example, an upper end portion of each of the headers (the first header 361 and the second header 362), and causes the inner space of the header to communicate with the inner spaces of the respective heat transfer tubes 10.

[0083] Furthermore, first partitions 30 are provided in the respective heat transfer tubes 10. Each of the first partitions 30 extend in the longitudinal direction of an associated one of the heat transfer tubes 10 (in the second direction D2, the up-down direction) to divide the inner spaces of the tube wall 11 of the heat transfer tube 10 in the width direction of the heat transfer tube 10 (the third direction D3, the front-back direction). As illustrated in FIG. 19, the first partition 30 has an upper end 30e that is located at a lower position than the upper opening end 10e of the heat transfer tube 10, whereby a return flow passage P1at is provided in an upper region of the inner space of the tube wall 11, the return flow passage P1at allowing the refrigerant to flow in the front-back direction (the third direction D3). That is, the heat transfer passage P1a for refrigerant in the heat transfer tube 10 has an inverted U-shape including the return flow passage P1at.

[0084] As illustrated in FIG. 18, the refrigerant flow passage of the heat exchanger 101 includes the heat transfer passages P1a and two header flow passages P1h that are provided in a lower region of the heat exchanger 101, arranged in the front-back direction, and intersect with the heat transfer passages P1a.

[0085] In the heat exchanger 101 as illustrated in FIGS. 17 to 19, the refrigerant first flows into the first header 361 that penetrates lower rear portions of the heat transfer tubes 10 in the lateral direction. As illustrated in FIG. 18, the refrigerant that has flowed into the first header 361 flows from left to right in the header flow passage P1h in the first header 361. In this process, the refrigerant is distributed to the heat transfer tubes 10 via the communication holes 60h provided in the first header 361, and flows into the heat transfer passages P1a of the heat transfer tubes 10. As illustrated in FIG. 19, in each of the heat transfer passages P1a, the refrigerant flows upward through the rear side in the inner space of the tube wall 11, flows forward in the return flow passage P1at in the upper region of the inner space of the tube wall 11, and then flows downward through the front side in the inner space of the tube wall 11.

[0086] At this time, as illustrated in FIG. 18, the refrigerant exchanges heat, via the tube walls 11, with air flowing through spaces (that is, the air flow passages P2) provided between the tube walls 11 of the heat transfer tubes 10. As illustrated in FIGS. 17 and 18, refrigerant from the heat transfer passages P1a flows into the header flow passage P1h in the second header 362, which penetrates lower front portions of the heat transfer tubes 10, and then merges together in the header flow passage P1h. The refrigerant that has merged together in the header flow passage P1h in the second header 362 flows out from the second pipe b located on the left side of the second header 362 to the outside of the heat exchanger 101 (for example, the expansion valve 105 of the refrigerant circuit 100c as illustrated in FIG. 2).

[0087] It should be noted that the heat exchanger 101 as illustrated in FIGS. 17 to 19 is merely an example of the heat exchanger 101 according to the present invention, and the shape of the heat transfer passage P1a, the presence or absence of the first partition 30 in the heat transfer tube 10, the number of first partitions 30 in the heat transfer tube 10, the location of the first partition 30 or the first partitions 30 in the heat transfer tube 10, the locations of the first pipe a and the second pipe b in the heat exchanger 101, etc., may be changed as appropriate.

[0088] FIG. 20 is a perspective view schematically illustrating an external appearance of a second modification of the configuration of the flow passage in the heat exchanger 101 as illustrated in FIG. 1. In the heat exchanger 101 as illustrated in FIG. 20, two headers (a first header 461 and a second header 462) are respectively provided in central part of lower part and central part of upper part of the heat exchanger 101 in the front-back direction (the third direction D3). Referring to FIG. 20, the first header 461 provided with the first pipe a and the second pipe b is disposed at the lower part, and the second header 462 is disposed at the upper part. The first pipe a is provided at a left end of the first header 461, and the second pipe b is provided at a right end of the first header 461. Although it is not illustrated, in each of the first header 461 and the second header 362, the communication holes 60h are provided.

[0089] The heat exchanger 101 as illustrated in FIG. 20 includes a second partition 40 that divides the header flow passage P1h in the arrangement direction of the heat transfer tubes 10 (the first direction D1). The second partition 40 blocks the forward movement of the refrigerant in the first direction D1 between the adjacent heat transfer passages P1a. In the heat exchanger as illustrated in FIG. 20, one second partition 40 is provided at the first header 461 provided with the first pipe a and the second pipe b. It should be noted that the first header 461 and the second header 462 may be formed to include respective second partitions 40. In addition, it suffices that the number of second partitions 40 provided in each of the headers is also determined as appropriate on the basis of a desired configuration of the flow passage.

[0090] Although it is not illustrated, the refrigerant flow passage of the heat exchanger 101 as illustrated in FIG. 20 includes the heat transfer passages P1a, and the two header flow passages P1h arranged in the lower part and the upper part of the central part of the heat exchanger 101 in the front-back direction, each of the two header flow passages P1h intersecting the heat transfer passages P1a. However, the header flow passage P1h of the first header 461 is divided by the second partition 40 into left part where the first pipe a is provided and right part where the second pipe b is provided. The first partition 30 as illustrated in FIGS. 17 to 19 is not provided in the heat exchanger 101 as illustrated in FIG. 20, and the inner space of each tube wall 11 forms one heat transfer passage P1a having an I-shape.

[0091] In the heat exchanger 101 as illustrated in FIG. 20, the refrigerant first flows into the left part of the header flow passage P1h of the first header 461, which penetrates lower parts of the heat transfer tubes 10, and then flows through this left part from left to right. In this process, the refrigerant is distributed to and flows into the heat transfer passages P1a of some heat transfer tubes 10 located at the left part of the plurality of heat transfer tubes 10. The refrigerant that has flowed into the heat transfer passages P1a of the above some heat transfer tubes 10 located at the left part flows upward through the inner spaces of the tube walls 11, and then merges together within the header flow passage P1h of the second header 462, which penetrates the upper parts of the heat transfer tubes 10.

[0092] Then, in the process of flowing of refrigerant through the header flow passage P1h toward the right side, the refrigerant is distributed to and flows into the heat transfer passages P1a of some heat transfer tubes 10 located at the right part of the plurality of heat transfer tubes 10, and flows downward. When flowing upward through the heat transfer passages P1a of some heat transfer tubes 10 located at the left part, and when flowing downward through the heat transfer passages P1a of some heat transfer tubes 10 located at the right part, the refrigerant exchanges heat, via the tube walls 11, with air flowing through spaces (that is, the air flow passages P2) provided between the tube walls 11 of the heat transfer tubes 10. Thereafter, the refrigerant from the heat transfer passages P1a of some heat transfer tubes 10 located at the right part flows into the right part of the header flow passage P1h of the first header 461, merges together within this right part, and then flows out from the second pipe b to the outside of the heat exchanger 101 (for example, the expansion valve 105 of the refrigerant circuit 100c as illustrated in FIG. 2).

[0093] In the heat exchanger 101 according to the present invention, both ends of the heat transfer tubes 10 in the tube axial direction are sealed. A sealing structure of sealing the both ends of the heat transfer tubes 10 in the tube axial direction may have the function of defining the tube pitch Lp, like the tube pitch defining parts 20 and 120 as illustrated in FIGS. 2 and 7, or may be provided as a separate member from the tube pitch defining part 220, like the tube sealing parts 70 as illustrated in FIG. 8. In the case where the sealing structure and the tube pitch defining parts are formed of different materials, the sealing structure may be formed by collapsing the end portions itself of the heat transfer tubes 10, instead of using cap-shaped parts that cover the opening ends 10e of the heat transfer tubes 10, as well as the tube sealing parts 70 as illustrated in FIG. 8.

[0094] As described above, the heat exchanger 101 according to Embodiment 1 includes: the plurality of heat transfer tubes 10 each of which allows a fluid to flow therein, and has both ends in the tube axial direction (the second direction D2) that are sealed, the plurality of heat transfer tubes 10 being arranged in the first direction D1 crossing the tube axial direction; the tube pitch defining parts 20 configured to define the tube pitch Lp of the heat transfer tubes 10 in the first direction D1; and one or more headers (for example, the upper header 61) penetrating the heat transfer tubes 10 in the first direction D1 to couple the heat transfer tubes 10 together. Each of the heat transfer tubes 10 has one or more header insertion holes 10h1 into which the one or more headers are inserted, the one or more header insertion holes 10h1 extending through the heat transfer tube 10 in the first direction D1, and each of the one or more headers has the communication holes 60h each of which causes the inside of the header to communicate with the inside of an associated one of the heat transfer tubes 10.

[0095] As described above, the heat exchanger 101 is configured such that the tube pitch Lp of the heat transfer tubes 10 in the first direction D1 is determined by the tube pitch defining parts 20, which are separate from the headers, and each header penetrates the heat transfer tubes 10 in the first direction D1 to couple the heat transfer tubes 10 together. Therefore, unlike existing headers, it is unnecessary to provide tube holes in the headers, into which the end portions of the heat transfer tubes 10 are inserted, and a force that supports the heat transfer tube 10 is not applied to the peripheral edge portions of the communication holes 60h of the headers. As a result, the distance between the opening ports (the communication holes 60h in the present invention) can be shortened as compared with the existing headers, and the tube pitch Lp can be reduced.

[0096] In each of the heat transfer tubes 10, the peripheral edge protruding part 12 extending in the first direction D1 is provided at the peripheral edge portion of each of the one or more header insertion holes 10h1. Therefore, the header (the upper header 61) can be supported, and can also be guided in the insertion direction when the heat transfer tubes 10 and the header are assembled.

[0097] Each of the heat transfer tubes 10 includes the first tube-side wall part 10a and the second tube-side wall part 10b, the first tube-side wall part 10a being located on one side in the first direction D1, the second tube-side wall part 10b being located on the other side in the first direction D1. Each of the one or more header insertion holes 10h1 includes the first hole ha and the second hole hb, the first hole ha being provided in the first tube-side wall part 10a of each of the heat transfer tubes 10 each having one or more header insertion holes 10h1, the second hole hb being provided in the second tube-side wall part 10b of the heat transfer tube 10.

[0098] The peripheral edge protruding part 12 includes the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b, the first peripheral edge protruding part 12a being formed at the peripheral edge portion of the first hole ha of the first tube-side wall part 10a, and extending toward one side in the first direction D1, the second peripheral edge protruding part 12b being formed at the peripheral edge portion of the second hole hb of the second tube-side wall part 10b, and extending toward the other side in the first direction D1. In the first direction D1, each of the communication holes 60h of each of the one or more headers is disposed between the distal ends of the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b of the heat transfer tube 10 that communicates with the communication hole 60h.

[0099] The first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b that extend in opposite directions are provided at the heat transfer tube 10 as described above. Therefore, even when the communication holes 60h of the header are slightly displaced relative to the heat transfer tubes 10 in the first direction D1, it is possible to reduce the likelihood that leakage of refrigerant will occur, because of provision of the first peripheral edge protruding parts 12.

[0100] Each of the heat transfer tubes includes the first tube-side wall part 10a and the second tube-side wall part 10b, the first tube-side wall part 10a being located on one side in the first direction D1, the second tube-side wall part 10b being located on the other side in the first direction D1. Each of the one or more header insertion holes 10h1 includes the first hole ha and the second hole hb, the first hole ha being provided in the first tube-side wall part 10a of the heat transfer tube 10 having the one or more header insertion holes 10h1, the second hole hb being provided in the second tube-side wall part 10b of the heat transfer tube 10.

[0101] The peripheral edge protruding part 12 includes the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b, the first peripheral edge protruding part 12a being formed at the peripheral edge portion of the first hole ha of the first tube-side wall part 10a and extending toward the one side in the first direction D1, the second peripheral edge protruding part 12b being formed at the peripheral edge portion of the second hole hb of the second tube-side wall part 10b and extending toward the one side in the first direction D1. In the first direction D1, each of the communication holes 60h of each of the one or more headers is disposed between the distal end of the first peripheral edge protruding part 12a and the outer surface of the second tube-side wall part 10b of the heat transfer tube 10 that communicates with the communication hole 60h.

[0102] In such a manner, the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b that extend toward the same side (for example, toward the left side) are provided at the first tube-side wall part 10a and the second tube-side wall part 10b of the heat transfer tube 10. Thus, even when the communication holes 60h of the header are slightly displaced relative to the heat transfer tubes 10 toward one side (left side) in the first direction, it is possible to reduce the likelihood that leakage of refrigerant will occur, because of provision of the first peripheral edge protruding parts 12a.

[0103] Each of the heat transfer tubes 10 includes the first tube-side wall part 10a and the second tube-side wall part 10b that are located on respective sides in the first direction D1. Each of the one or more header insertion holes 10h1 includes the first hole ha and the second hole hb that are provided in the first tube-side wall part 10a and the second tube-side wall part 10b, respectively, of the heat transfer tube 10 having the one or more header insertion holes 10h1.

[0104] The peripheral edge protruding part 12 includes the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b. The first peripheral edge protruding part 12a is formed at the peripheral edge portion of the first hole ha of the first tube-side wall part 10a, and extends toward the one side in the first direction D1, and the second peripheral edge protruding part 12b is formed at the peripheral edge portion of the second hole hb of the second tube-side wall part 10b, and extends toward the other side in the first direction D1.

[0105] The first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b include the inclined tapered portion 12at and 12bt, respectively, at the proximal ends of first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b. In the first direction D1, the width Wh of each of the communication holes 60h formed in each of the one or more headers is greater than the distance between the first tube-side wall part 10a and the second tube-side wall part 10b of each of the heat transfer tubes 10.

[0106] In such a manner, since the first peripheral edge protruding part 12a and the second peripheral edge protruding part 12b have the tapered portions 12at and 12bt, respectively, in the first direction D1, the width Wh of each communication hole 60h of the header can be made greater than the width W of the heat transfer passage P1a in the first direction D1, and it is therefore possible to ensure the amount of refrigerant to be distributed to the heat transfer tubes 10.

[0107] The communication holes 60h provided in each of the one or more headers are arranged at the intervals Lh equal to the tube pitch Lp in the first direction D1 such that two or more communication holes 60h are provided for each of the heat transfer tubes 10. The two or more communication holes 60h are arranged in the direction (the third direction D3) orthogonal to the first direction D1 and the tube axial direction of the heat transfer tube 10 that communicates with the two or more communication holes 60h. With such a configuration, maldistribution of the refrigerant in the longitudinal direction of the cross section of the heat transfer tube 10 (the third direction D3) is reduced.

[0108] The communication holes 60h provided in each of the one or more headers are arranged at the intervals Lh equal to the tube pitch Lp in the first direction D1 such that one communication hole 60h is provided for each of the heat transfer tubes 10. The one communication hole 60h is shaped in such a manner as to extend in a direction (the third direction D3) orthogonal to the first direction D1 and the tube axial direction of one of the heat transfer tubes 10 that communicates with the one communication hole 60h. With such a configuration, maldistribution of the refrigerant in the longitudinal direction of the cross section of the heat transfer tube 10 (the third direction D3) is reduced.

[0109] The one or more headers (for example, the upper header 161) include the small-diameter headers 161a, 161b, and 161c that penetrate the heat transfer tubes 10 in the first direction D1 and are arranged in the direction (the third direction D3) orthogonal to the first direction D1 and the tube axial direction in each of the heat transfer tubes 10.

[0110] In such a manner, since the header (for example, the upper header 161) includes the small-diameter headers 161a, 161b, and 161c, the opening diameter of each of the header insertion holes 10h1a, 10h1b, and 10h1c is set to be small. Thus, a heat transfer area is increased in the tube axial direction of the heat transfer tube 10 (the second direction D2) and the heat exchange performance of the heat exchanger 101 is improved. In addition, the maldistribution of the liquid in the third direction D3 is reduced and improved distribution is achieved, thus improving the heat exchange performance.

[0111] The one or more headers include the elliptical header 261 that penetrates the heat transfer tubes 10 in the first direction D1 and that has an elliptical cross section perpendicular to the first direction D1. The elliptical header 261 penetrates the heat transfer tubes 10 such that the longitudinal direction of the cross section of the elliptical header 261 coincides with the direction (the third direction D3) orthogonal to the first direction D1 and the tube axial direction in each of the heat transfer tubes 10.

[0112] Since the header is formed to include the elliptical header 261 as described above, the opening width of the header insertion hole 10h1 in the tube axial direction (the second direction D2) can be set to be small and the heat transfer area is increased. It is therefore possible to reduce the number of parts as compared with the case where the header is formed to include the small-diameter headers 161a, 161b, and 161c.

[0113] In a state in which the heat exchanger 101 is disposed such that the tube axial direction coincides with the vertical direction, each of the communication holes 60h of each of the one or more headers is provided such that Φ satisfies ΦDo < Φ < ΦDs, where Φ is the angle of the communication hole 60h in the case where the vertically downward direction from the center Ch of the header peripheral wall is defined as 0 degrees, ΦDo is the angle of a liquid surface on the assumption that a slip ratio between gas and liquid of a fluid is 1 and a gas-liquid interface is flat and horizontal, and ΦDs is an angle of the liquid surface of the fluid in the header peripheral wall. It should be noted that ΦDo is expressed by (-0.0408 × As + 74.124) × 0.62, and ΦDs is expressed by (-0.0408 × As + 74.124) × 1.2, where As [mm 2< ] is the cross-sectional area of the flow passage in the header peripheral wall.

[0114] Therefore, in the header peripheral wall, the communication hole 60h is provided at a position likely to be close to the liquid surface, and the ratio between liquid and gas that are distributed to each of the heat transfer tubes 10 is substantially uniform. Therefore, the distribution performance of the header is improved and the performance of the heat exchanger 101 is also improved.

[0115] The tube pitch defining parts 20 and 120 are disposed in such a manner as to cover one end of each of the heat transfer tubes 10 in the tube axial direction, and includes: the plurality of engagement parts (the groove parts 22 and the protruding parts 122) and the connection parts (the flat connection parts 21), the engagement parts being engaged with the one ends of the heat transfer tubes 10; and the connection parts connecting adjacent ones of the engagement parts. The tube pitch defining parts 20 and 120 seal one ends of the heat transfer tubes 10.

[0116] With the above configuration, by the tube pitch defining parts 20 and 120, the tube pitch Lp can be determined and one end of each of the of heat transfer tubes 10 can be sealed. Therefore, even in the case where heat transfer tubes 10 each having one open end in the tube axial direction are used, the heat transfer tubes 10 can be sealed by the tube pitch defining part 20 and 120, and it is possible to easily manufacture the heat exchanger 101.

[0117] The tube pitch defining parts 220 are protrusion parts each of which protrudes outward from the tube wall 11 of an associated one of the heat transfer tubes 10. Therefore, it is unnecessary to assemble the tube pitch defining parts 220 and the heat transfer tubes 10, and the heat exchanger 101 can be thus easily manufactured.

[0118] The air-conditioning apparatus 100 according to Embodiment 1 includes the fluid circuit (the refrigerant circuit 100c) in which the compressor 102, the above heat exchanger 101, the expansion valve 105, and the indoor heat exchanger 104 are connected by pipes, and fluid circulates. The air-conditioning apparatus 100 includes the heat exchanger 101 in which the heat transfer tubes are arranged at a smaller tube pitch Lp and a higher performance is achieved than in an existing heat exchanger, and an efficient operation is performed and energy savings are thus expected.List of Reference Signs

[0119] 10: heat transfer tube 10a: first tube-side wall part 10b: second tube-side wall part 10c: connecting wall part 10d: connecting wall part 10e: opening end 10h1: header insertion hole 10h1a: header insertion hole 10h1b: header insertion hole 10h1c: header insertion hole 10h2: header insertion hole 11: tube wall 12: peripheral edge protruding part 12a: first peripheral edge protruding part 12ae: distal end portion 12at: tapered portion 12b: second peripheral edge protruding part 12be: distal end portion 12bt: tapered portion 20: tube pitch defining part 21: flat connection part 22: groove part 30: first partition 30e: upper end 40: second partition 50: heat transfer fin 60h: communication hole 61: upper header 62: lower header 70: tube sealing part 100: air-conditioning apparatus 100A: outdoor unit 100B: indoor unit 100c: refrigerant circuit 101: heat exchanger 102: compressor 103: four-way valve 104: indoor heat exchanger 105: expansion valve 106: indoor fan 107: outdoor fan 120: tube pitch defining part 122: protruding part 161: upper header 161a: small-diameter header 161b: small-diameter header 161c: small-diameter header 210: heat transfer tube 220: tube pitch defining part 221: first protrusion part 222: second protrusion part 261: elliptical header 361: first header 362: second header 461: first header 462: second header Ax: tube axis Ch: center D1: first direction D2: second direction D3: third direction Lp: tube pitch Lr: pitch Lr1: pitch P1a: heat transfer passage P1at: return flow passage P1h: header flow passage P2: flow passage W1: outer diameter W2: outer diameter W3: outer diameter a: first pipe b: second pipe ha: first hole hb: second hole Φ: angle

Claims

1.

1. A heat exchanger comprising: a plurality of heat transfer tubes allowing a fluid to flow therethrough, and each having both ends in a tube axial direction that are sealed, the plurality of heat transfer tubes being arranged in a first direction crossing the tube axial direction; a tube pitch defining part configured to define a tube pitch of the plurality of heat transfer tubes in the first direction; and one or more headers penetrating the plurality of heat transfer tubes in the first direction to couple the plurality of heat transfer tubes together, wherein each of the plurality of heat transfer tubes has one or more header insertion holes into which the one or more headers are inserted, the one or more header insertion holes extending through the heat transfer tube in the first direction, and each of the one or more headers has a plurality of communication holes each causing the header to communicate with the inside of an associated one of the plurality of heat transfer tubes.

2.

2. The heat exchanger of claim 1, wherein at a peripheral edge portion of each of the one or more header insertion holes of each of the plurality of heat transfer tubes, a peripheral edge protruding part is provided to extend in the first direction.

3.

3. The heat exchanger of claim 2, wherein each of the plurality of heat transfer tubes includes a first tube-side wall part located on one side in the first direction and a second tube-side wall part located on an other side in the first direction, each of the one or more header insertion holes includes a first hole and a second hole, the first hole being provided in the first tube-side wall part of each of the plurality of heat transfer tubes each having the one or more header insertion holes, the second hole being provided in the second tube-side wall part of the heat transfer tube, the peripheral edge protruding part includes a first peripheral edge protruding part and a second peripheral edge protruding part, the first peripheral edge protruding part being formed at a peripheral edge portion of the first hole of the first tube-side wall part, and extending toward the one side in the first direction, the second peripheral edge protruding part being formed at a peripheral edge portion of the second hole of the second tube-side wall part, and extending toward the other side in the first direction, and in the first direction, each of the plurality of communication holes of each of the one or more headers is disposed between distal ends of the first peripheral edge protruding part and the second peripheral edge protruding part of the heat transfer tube that communicates with the communication hole.

4.

4. The heat exchanger of claim 2, wherein each of the plurality of heat transfer tubes includes a first tube-side wall part located on one side in the first direction and a second tube-side wall part located on an other side in the first direction, each of the one or more header insertion holes includes a first hole and a second hole, the first hole being provided in the first tube-side wall part of each of the plurality of heat transfer tubes each having the one or more header insertion holes, the second hole being provided in the second tube-side wall part of the heat transfer tube, the peripheral edge protruding part includes a first peripheral edge protruding part and a second peripheral edge protruding part, the first peripheral edge protruding part being formed at a peripheral edge portion of the first hole of the first tube-side wall part, and extending toward the one side in the first direction, the second peripheral edge protruding part being formed at a peripheral edge portion of the second hole of the second tube-side wall part, and extending toward the one side in the first direction, and in the first direction, each of the plurality of communication holes of each of the one or more headers is disposed between a distal end of the first peripheral edge protruding part and an outer surface of the second tube-side wall part of the heat transfer tube that communicates with the communication hole.

5.

5. The heat exchanger of claim 2, wherein each of the plurality of heat transfer tubes includes a first tube-side wall part located one side in the first direction and a second tube-side wall part located on an other side in the first direction, each of the one or more header insertion holes includes a first hole and a second hole, the first hole being provided in the first tube-side wall part of each of the plurality of heat transfer tubes each having the one or more header insertion holes, the second hole being provided in the second tube-side wall part of the heat transfer tube, the peripheral edge protruding part includes a first peripheral edge protruding part and a second peripheral edge protruding part, the first peripheral edge protruding part being formed at a peripheral edge portion of the first hole of the first tube-side wall part, and extending toward the one side in the first direction, the second peripheral edge protruding part being formed at a peripheral edge portion of the second hole of the second tube-side wall part, and extending toward the other side in the first direction, each of the first peripheral edge protruding part and the second peripheral edge protruding part includes an inclined tapered portion at a proximal end thereof, and in the first direction, a width of each of the plurality of communication holes formed in each of the one or more headers is greater than a distance between the first tube-side wall part and the second tube-side wall part of each of the plurality of heat transfer tubes.

6.

6. The heat exchanger of any one of claims 1 to 5, wherein in each of the one or more headers, the plurality of communication holes are provided at intervals equal to the tube pitch in the first direction such that two or more communication holes are provided for each of the plurality of heat transfer tubes, and the two or more communication holes are arranged in a direction orthogonal to the first direction and the tube axial direction of the heat transfer tube that communicates with the two or more communication holes.

7.

7. The heat exchanger of any one of claims 1 to 5, wherein the plurality of communication holes are provided in each of the one or more headers at intervals equal to the tube pitch in the first direction such that one communication hole is provided for each of the plurality of heat transfer tubes, and the one communication hole is shaped to extend in a direction orthogonal to the first direction and the tube axial direction of the heat transfer tube that communicates with the one communication hole.

8.

8. The heat exchanger of any one of claims 1 to 7, wherein the one or more headers include a plurality of small-diameter headers that penetrate the plurality of heat transfer tubes in the first direction and that are arranged in the direction orthogonal to the first direction and the tube axial direction in each of the plurality of heat transfer tubes.

9.

9. The heat exchanger of any one of claims 1 to 7, wherein the one or more headers include an elliptical header that penetrates the plurality of heat transfer tubes in the first direction and that has an elliptical cross section perpendicular to the first direction, and the elliptical header penetrates the plurality of heat transfer tubes such that a longitudinal direction of the cross section of the elliptical header coincides with the direction orthogonal to the first direction and the tube axial direction in each of the plurality of heat transfer tubes.

10.

10. The heat exchanger of any one of claims 1 to 9, wherein in a state in which the heat exchanger is disposed such that the tube axial direction coincides with a vertical direction, each of the communication holes of each of the one or more headers is provided such that Φ satisfies ΦDo < Φ < ΦDs, where Φ is an angle of the communication hole in a case where a vertically downward direction from the center of the header peripheral wall is defined as 0 degrees, ΦDo is an angle of a liquid surface of the fluid on the assumption that a slip ratio between gas and liquid of the fluid is 1 and a gas-liquid interface is flat and horizontal, and ΦDs is an angle of a liquid surface of the fluid in the header peripheral wall, and ΦDo is expressed by (-0.0408 × As + 74.124) × 0.62, and ΦDs is expressed by (-0.0408 × As + 74.124) × 1.2, where As [mm2] is a cross-sectional area of the flow passage in the header peripheral wall.

11.

11. The heat exchanger of any one of claims 1 to 10, wherein the tube pitch defining part is disposed to cover one end of each of the plurality of heat transfer tubes in the tube axial direction, and includes a plurality of engagement parts and a connection part, each of the plurality of engagement parts being engaged with the one ends of the plurality of heat transfer tubes, the connection part connecting adjacent ones of the plurality of engagement parts, the tube pitch defining part being configured to seal the one end of each of the plurality of heat transfer tubes.

12.

12. The heat exchanger of any one of claims 1 to 10, wherein the tube pitch defining part is a protrusion part that protrudes outward from a tube wall of each of the plurality of heat transfer tubes.

13. 13 An air-conditioning apparatus comprising a fluid circuit in which a compressor, the heat exchanger of any one of claims 1 to 12, an expansion valve, and an indoor heat exchanger are connected by pipes, and the fluid circulates.

Images