JP2020020574A - Heat exchanger - Google Patents

Abstract

To suppress increase of pressure loss when a refrigerant flows in each of refrigerant flow channels and to easily perform a bending work in a width direction of flat tubes, in a heat exchanger in which the plurality of refrigerant flow channels are formed inside of the flat tubes.SOLUTION: A plurality of row portions (30, 40) having a plurality of flat tubes (31, 41) are arranged in an air passing direction, the plurality of row portions (30, 40) are constituted so that a refrigerant flows in parallel in each of flat tubes (31, 41) between the plurality of row portions (30, 40), the flat tubes (31, 41) of the plurality of row portions (30, 40) respectively have one or more bent portions (33a, 33b, 33c) bent in a width direction of the flat tubes (31, 41) in a manner that the flat tubes (31, 41) of the row portions (30, 40) adjacent to each other are along to each other in the air passing direction.SELECTED DRAWING: Figure 2

Description

    The present invention relates to a heat exchanger and an air conditioner.

    BACKGROUND ART Conventionally, a heat exchanger including a number of flat tubes arranged in parallel and fins joined to the flat tubes has been known. Patent Document 1 (see FIG. 2) discloses this type of heat exchanger. This heat exchanger is a single-row heat exchanger in which flat tubes are arranged in a single row in the air passage direction. The heat exchanger has an upper heat exchange region (main heat exchange region) and a lower heat exchange region (auxiliary heat exchange region). The number of flat tubes in the lower heat exchange region is smaller than the number of flat tubes in the upper heat exchange region.

    For example, when this heat exchanger functions as an evaporator, the refrigerant in a saturated liquid state flows through the lower heat exchange region, absorbs heat from air and evaporates. This refrigerant flows through the upper heat exchange region, evaporates further, and is overheated and flows out of the heat exchanger.

JP 2012-163328 A

    By the way, in order to improve the performance of the heat exchanger as disclosed in Patent Document 1, it is conceivable to increase the length of the flat tube and increase the flow path length of the refrigerant flow path inside the flat tube. . However, if the overall length of the refrigerant flow path is increased in this way, the pressure loss when the refrigerant passes will increase.

    Further, in a heat exchanger having a large number of refrigerant flow paths formed inside a flat tube, the flow area of each refrigerant flow path is relatively small, so that the flow velocity of the refrigerant flowing through each refrigerant flow path is likely to increase. For this reason, the pressure loss of the refrigerant flowing through each refrigerant flow path is further increased.

    On the other hand, in order to suppress such an increase in pressure loss, it is conceivable to adopt a configuration in which the flat tubes are lengthened in the width direction (the direction in which air passes) to increase the number of refrigerant flow paths. However, when the width of the flat tube is increased in this way, it becomes difficult to bend the flat tube in the width direction, and the heat of another surface (for example, four surfaces) having a plurality of side portions through which air passes is provided. It becomes difficult to manufacture the exchanger.

    The present invention has been made in view of such a point, and an object of the present invention is to provide a heat exchanger in which a plurality of refrigerant flow paths are formed inside a flat tube, the pressure loss when the refrigerant flows through each refrigerant flow path. It is an object of the present invention to suppress the increase in the width of the flat tube and facilitate the bending in the width direction of the flat tube.

    According to a first aspect of the present invention, there are provided a plurality of flat tubes (31, 41) each of which is arranged in parallel with each other and has a plurality of refrigerant flow paths (C), and fins joined to the flat tubes (31, 41). (32, 42), and a plurality of row portions (31, 41) having a plurality of flat tubes (31, 41) for a heat exchanger that exchanges heat between the refrigerant flowing through the refrigerant flow path (C) and air. 30, 40) are arranged in the air passage direction, and the plurality of row portions (30, 40) are arranged in parallel with the refrigerant in the flat tubes (31, 41) between the plurality of row portions (30, 40). The flat tubes (31, 41) of the plurality of rows (30, 40) are formed so as to flow, and the flat tubes (31, 41) of the rows (30, 40) adjacent to each other in the air passage direction. The flat tubes (31, 41) are characterized by having one or more bent portions (33a, 33b, 33c) bent in the width direction of the flat tubes (31, 41) along each other.

    In the first invention, a plurality of rows (30, 40) are provided in the air passage direction, and a plurality of flat tubes (31, 41) are arranged in parallel in each row (30, 40). When the refrigerant flows through the heat exchanger, the refrigerant flows in parallel through the flat tubes (31, 41) of the respective row portions (30, 40). For example, when the refrigerant flows by connecting the flat tubes (31, 41) of such row portions (30, 40) in series, the flow rate of the refrigerant flowing through each refrigerant channel (C) increases, The flow velocity of the refrigerant flowing through (C) increases. Further, the flow path length of each refrigerant flow path (C) also becomes longer. On the other hand, in the present invention, since the refrigerant flows through the flat tubes (31, 41) of the respective row portions (30, 40) in parallel, the flow rate of the refrigerant flowing through each refrigerant flow path (C) decreases, The flow velocity of the refrigerant flowing through the flow path (C) also decreases. Further, the flow path length of each refrigerant flow path (C) also becomes short. The pressure loss of the refrigerant flowing through the refrigerant channel (C) is proportional to the square of the flow velocity of the refrigerant and the length of the refrigerant channel (C). Therefore, with such a configuration, pressure loss can be reduced.

    In the heat exchanger, the flat tubes (31, 41) of the adjacent row portions (30, 40) are formed so as to be along each other, and one or more bent portions (33a, 33a, 33) of each flat tube (31, 41) are formed. 33b, 33c). For this reason, the bending process of the flat tubes (31, 41) becomes easier as compared with a configuration in which the single-row flat tubes (31, 41) are elongated in the width direction.

    In a second aspect based on the first aspect, each of the row portions (30, 40) includes a plurality of flat tubes arranged in the direction in which the flat tubes (31, 41) of the row portions (30, 40) are arranged. (31,41) to the main heat exchange area (35,45) and the flat heat pipe (31,41) having a smaller number of flat tubes (31,41) than the main heat exchange area (35,45) Corresponding auxiliary heat exchange regions (37, 47) are formed, and the plurality of row portions (30, 40) are arranged so that the main heats adjacent to each other in the air passage direction between the plurality of row portions (30, 40). It is characterized in that the refrigerant is configured to flow in parallel in the exchange area (35, 45) and each auxiliary heat exchange area (37, 47).

    In the second invention, a main heat exchange area (35, 45) and an auxiliary heat exchange area (37, 47) are formed in each row (30, 40). The refrigerant flows into the flat heat pipes (31, 41) in the main heat exchange area (35, 45) in each row (30, 40) and the auxiliary heat exchange area (37, 47) in each row (30, 40). Flow in parallel through each of the flat tubes (31, 41). Thereby, the pressure loss of the refrigerant flowing through each main heat exchange area (35, 45) and each auxiliary heat exchange area (37, 47) can be reduced.

    In a third aspect based on the second aspect, the plurality of row portions (30, 40) are formed such that each of the main heat exchange areas (35, 45) between the row portions (30, 40) adjacent in the air passage direction and The refrigerant flows in the flat tubes (31, 41) of the auxiliary heat exchange areas (37, 47) in the same direction, and the main heat exchange areas of the row portions (30, 40) The gas branch pipe (29) communicating with one end of each flat pipe (31, 41) of the (35, 45) and the auxiliary heat exchange area (37, 37) of the row section (30, 40). 47) The liquid branch pipe (28) communicating with one end of the flat pipe (31, 41) on the gas branch pipe (29) side so as to be branched, and the respective row sections (30, 40). The other end of each flat tube (31, 41) of the main heat exchange area (35, 45) and each flat tube (31) of each auxiliary heat exchange area (37, 47) of each row (30, 40). , 41) and a communication pipe (68, 88) that communicates with the other end.

    In the third invention, in each main heat exchange area (35, 45) and each auxiliary heat exchange area (37, 47) of the adjacent row section (30, 40), the refrigerant flowing through each flat tube (31, 41) Are the same as each other. The connecting pipes (68, 88), the liquid branch pipe (28), and the gas branch pipe (29) are connected to the respective row portions (30, 40). Specifically, in each row portion (30, 40), a gas branch pipe (29) and a liquid branch pipe (28) are provided at one end side of the flat pipe (31, 41), and the flat pipe (31, 41) is provided. ) Are provided with communication pipes (68, 88) on the other end side. Thereby, in the heat exchanger, the arrangement space for the gas branch pipe (29) and the liquid branch pipe (28) is concentrated.

    In a fourth aspect based on the first or second aspect, when the plurality of row portions (30, 40) function as an evaporator, the flat portions between the row portions (30, 40) adjacent to each other in the air passage direction. The pipes (31, 41) are characterized in that the directions in which the refrigerant flows are opposite to each other.

    In the fourth aspect, when the heat exchanger functions as an evaporator, the refrigerant flows in parallel through the flat tubes (31, 41) of the row portions (30, 40) adjacent to each other in the air passage direction. Furthermore, in the flat tubes (31, 41) of the adjacent row portions (30, 40), the direction of the refrigerant is opposite. If the flow direction of the refrigerant is the same in the flat tubes (31, 41) of the adjacent row portions (30, 40), the refrigerant flows in the flat tubes (31, 41) of the adjacent row portions (30, 40). Are likely to overlap in the air passage direction. On the other hand, in the flat tubes (31, 41) of the respective row portions (30, 40), since the temperature of the portion other than the superheated region of the refrigerant is low, moisture condensed in the air causes the flat tubes (31, 41) and the fins (31, 41). 32, 42) The surface is easily frosted. In such a state, the ventilation resistance of the air is reduced in the vicinity of the superheated area in each row (30, 40), so that the air tends to drift in this area. Then, in the heat exchanger, the air does not flow uniformly throughout, so that the heat exchange efficiency is reduced.

    On the other hand, in the present invention, since the flow of the refrigerant flowing through the flat tubes (31, 41) of the adjacent row portions (30, 40) is reversed, the flat tubes (31, 40) of the respective row portions (30, 40) are opposite. , 41) become farther from each other. Therefore, the drift of air can be prevented.

    In a fifth aspect based on the fourth aspect, when the plurality of row portions (30, 40) function as the evaporator, the flat tubes (30, 40) between the row portions (30, 40) adjacent to each other in the air passage direction. 31, 41), so that the superheated regions (S1, S2) of the refrigerant flowing through the refrigerant do not overlap with each other in the air passage direction.

    In each row (30, 40) of the fifth invention, the direction of the refrigerant in the flat tubes (31, 41) of the adjacent row (30, 40) is reversed, and The superheated areas (S1, S2) of the flat tubes (31, 41) are configured not to overlap. If the superheated regions (S1, S2) of the respective row portions (30, 40) overlap in the air passage direction, there is a risk that air will flow only through the overlapping portion. On the other hand, in the present invention, since the superheated regions (S1, S2) do not overlap, the air drift can be reliably prevented.

    In the sixth aspect, the heat exchanger (23) according to any one of the first to fifth aspects is provided in the refrigerant circuit (20) of the air conditioner (10). In the heat exchanger (23), the refrigerant circulating in the refrigerant circuit (20) absorbs heat from air and evaporates, or radiates heat to air and condenses.

    In the present invention, since the refrigerant flows in parallel in the flat tubes (31, 41) of the respective row portions (30, 40), the refrigerant flowing through the refrigerant flow path (C) of the flat tubes (31, 41) is formed. Pressure loss can be greatly reduced. As a result, a desired heat exchange efficiency can be obtained while suppressing an increase in power due to an increase in pressure loss.

    Further, since it is not necessary to lengthen the flat tubes (31, 41) in the width direction, it is easy to bend the flat tubes (31, 41) of the respective row portions (30, 40). Thereby, the flat tubes (31, 41) of each row portion (30, 40) can be bent to manufacture a two- to four-plane heat exchanger, and the heat exchanger can be made more compact. In addition, by reducing the width of each flat tube (31, 41), the ventilation resistance between the flat tubes (31, 41) in each row (30, 40) can be reduced, and the decrease in heat transmittance is suppressed. it can. Furthermore, since the width of the flat tubes (31, 41) is reduced, it is possible to prevent dew condensation water from staying above the flat tubes (31, 41). As a result, frost formation on the surfaces of the flat tubes (31, 41) can be prevented.

    In the second invention, the pressure loss of the refrigerant can be reduced in both the main heat exchange area (35, 45) and the auxiliary heat exchange area (37, 47).

    In the third invention, the liquid branch pipe (28) and the gas branch pipe (29) for flowing the refrigerant in parallel to the respective row portions (30, 40) can be arranged collectively. Thereby, the space of the piping can be made compact, or the installation of the piping can be facilitated.

    In the fourth and fifth inventions, when the heat exchanger functions as an evaporator, it is possible to prevent the superheated regions (S1, S2) of the refrigerant from overlapping. Thereby, it is possible to suppress the air from drifting only in the superheated regions (S1, S2). As a result, even if frost forms on the surfaces of the flat tubes (31, 41) and fins (32, 42) other than the superheated areas (S1, S2), air can be uniformly flowed throughout the heat exchanger. Therefore, the heat exchange efficiency and the evaporation performance can be improved.

FIG. 1 is a refrigerant circuit diagram illustrating a schematic configuration of the air conditioner according to the first embodiment. FIG. 2 is a schematic perspective view of the outdoor heat exchanger. FIG. 3 is a schematic configuration diagram in which an upwind row portion of the outdoor heat exchanger is developed in a plane, and shows a flow of a refrigerant when functioning as a condenser. FIG. 4 is a schematic configuration diagram in which the leeward row portion of the outdoor heat exchanger is developed in a plane, and shows the flow of the refrigerant when functioning as a condenser. FIG. 5 is an enlarged longitudinal sectional view of the portion indicated by A in FIG. FIG. 6 is an enlarged longitudinal sectional view of a portion indicated by B in FIG. FIG. 7 is a sectional view taken along line VII-VII of FIG. FIG. 8 is a sectional view taken along line VIII-VIII in FIG. FIG. 9 is a sectional view taken along the line VHI-VIIII of FIG. FIG. 10 is a sectional view taken along line XX of FIG. FIG. 11 is a graph showing temperature changes of refrigerant and air in the outdoor heat exchanger functioning as a condenser. FIG. 12 is a schematic configuration diagram in which the upwind row portion of the outdoor heat exchanger is developed in a plane, and shows the flow of the refrigerant when functioning as an evaporator.

FIG. 13 is a schematic configuration diagram in which the leeward row portion of the outdoor heat exchanger is developed in a plane, and illustrates the flow of the refrigerant when functioning as an evaporator. FIG. 14 is a graph showing temperature changes of refrigerant and air in the outdoor heat exchanger functioning as an evaporator. FIG. 15 is a diagram corresponding to FIG. 2 of the outdoor heat exchanger according to the second embodiment. FIG. 16 is a diagram corresponding to FIG. 3 of the outdoor heat exchanger according to the second embodiment. FIG. 17 is a diagram corresponding to FIG. 4 of the outdoor heat exchanger according to the second embodiment. FIG. 18 is a diagram corresponding to FIG. 12 of the outdoor heat exchanger according to the second embodiment. FIG. 19 is a diagram corresponding to FIG. 13 of the outdoor heat exchanger according to the second embodiment. FIG. 20 is a schematic top view of the outdoor heat exchanger functioning as a condenser. FIG. 21 is a diagram corresponding to FIG. 7 of the outdoor heat exchanger according to another embodiment.

    An embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

<< Embodiment 1 >>
The heat exchanger of the present embodiment is an outdoor heat exchanger (23) provided in the air conditioner (10). Hereinafter, the air conditioner (10) will be described first, and then the outdoor heat exchanger (23) will be described in detail.

<Overall configuration of air conditioner>
The air conditioner (10) will be described with reference to FIG.

    The air conditioner (10) includes an outdoor unit (11) and an indoor unit (12). The outdoor unit (11) and the indoor unit (12) are connected to each other via a liquid-side communication pipe (13) and a gas-side communication pipe (14). In the air conditioner (10), the outdoor unit (11), the indoor unit (12), the liquid side communication pipe (13), and the gas side communication pipe (14) are connected to form a refrigerant circuit (20). ing.

    The refrigerant circuit (20) is provided with a compressor (21), a four-way switching valve (22), an outdoor heat exchanger (23), an expansion valve (24), and an indoor heat exchanger (25). ing. The compressor (21), the four-way switching valve (22), the outdoor heat exchanger (23), and the expansion valve (24) are housed in the outdoor unit (11). The outdoor unit (11) is provided with an outdoor fan (15) for supplying outdoor air to the outdoor heat exchanger (23). The indoor heat exchanger (25) is housed in the indoor unit (12). The indoor unit (12) is provided with an indoor fan (16) for supplying indoor air to the indoor heat exchanger (25).

    The refrigerant circuit (20) is a closed circuit filled with the refrigerant. In the refrigerant circuit (20), the compressor (21) has its discharge pipe connected to the first port of the four-way switching valve (22) and its suction pipe connected to the second port of the four-way switching valve (22). Have been. In the refrigerant circuit (20), the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger (25) are sequentially arranged from the third port to the fourth port of the four-way switching valve (22). ) And are arranged. In this refrigerant circuit (20), the outdoor heat exchanger (23) is connected to the expansion valve (24) via a pipe (17), and the third of the four-way switching valve (22) is connected via a pipe (18). Connected to port.

    The compressor (21) is a scroll type or rotary type hermetic compressor. The four-way switching valve (22) includes a first state (a state shown by a solid line in FIG. 1) in which the first port communicates with the third port and a second port communicates with the fourth port, and a first state. The state is switched to a second state (a state shown by a broken line in FIG. 1) in which the port communicates with the fourth port and the second port communicates with the third port. The expansion valve (24) is a so-called electronic expansion valve.

  The outdoor heat exchanger (23) causes outdoor air to exchange heat with the refrigerant. The outdoor heat exchanger (23) will be described later. On the other hand, the indoor heat exchanger (25) causes indoor air to exchange heat with the refrigerant. The indoor heat exchanger (25) is configured by a so-called cross-fin type fin-and-tube heat exchanger including a heat transfer tube that is a circular tube.

−Operation of air conditioner−
The air conditioner (10) selectively performs a cooling operation and a heating operation.

    In the refrigerant circuit (20) during the cooling operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the first state. In this state, the refrigerant circulates in the order of the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger (25), and the outdoor heat exchanger (23) functions as a condenser, and the indoor heat exchanger (25) functions as an evaporator. In the outdoor heat exchanger (23), the gas refrigerant flowing from the compressor (21) radiates heat to outdoor air and condenses, and the condensed refrigerant flows out toward the expansion valve (24).

    In the refrigerant circuit (20) during the heating operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the second state. In this state, refrigerant circulates in the order of the indoor heat exchanger (25), the expansion valve (24), and the outdoor heat exchanger (23), and the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. The refrigerant that has been expanded into the gas-liquid two-phase state when passing through the expansion valve (24) flows into the outdoor heat exchanger (23). The refrigerant that has flowed into the outdoor heat exchanger (23) absorbs heat from outdoor air and evaporates, and then flows out toward the compressor (21).

<Overall configuration of outdoor heat exchanger>
The outdoor heat exchanger (23) according to the first embodiment will be described with reference to FIGS. Note that the number of flat tubes (31, 41) shown in the following description is merely an example.

    As shown in FIG. 2, the outdoor heat exchanger (23) is a four-sided air heat exchanger having four side portions (23a, 23b, 23c, 23d). Specifically, in the outdoor heat exchanger (23), the first side surface (23a), the second side surface (23b), the third side surface (23c), and the fourth side surface (23d) are continuously formed. Is done. The first side portion (23a) is located on the lower left side in FIG. 2, the second side portion (23b) is located on the upper left side in FIG. 2, and the third side portion (23c) is located on the upper right side in FIG. The fourth side surface portion (23d) is located on the lower right side in FIG. The heights of the side portions (23a, 23b, 23c, 23d) are substantially equal. Each width of the first side portion (23a) and the fourth side portion (23d) is shorter than the width of the second side portion (23b) and the third side portion (23c).

    In the outdoor heat exchanger (23), when the outdoor fan (15) is operated, the outdoor air outside each of the side portions (23a, 23b, 23c, and 23d) is moved to the respective side portions (23a, 23b, 23c, and 23c). 23d) flows inside (see the arrow in FIG. 2). This air is discharged from an air outlet formed in an upper portion of an outdoor casing (not shown).

    As shown in FIGS. 2 to 4, the outdoor heat exchanger (23) has a two-row structure having two row portions (30, 40) having flat tubes (31, 41) and fins (32, 42). Heat exchanger. The outdoor heat exchanger (23) may have three or more rows. In the outdoor heat exchanger (23) of the present embodiment, the leeward row portion (30) constitutes the leeward row portion (30) in the air passage direction, and the leeward row portion (40) constitutes the leeward row portion. ing. 3 and 4, the leeward row portion (30) and the leeward row portion (40) are each schematically shown by being developed in a plane.

    The outdoor heat exchanger (23) includes a first header collecting pipe (50), a second header collecting pipe (60), a third header collecting pipe (70), a fourth header collecting pipe (80), a first branch unit ( 91), and a second branch unit (92). The first header collecting pipe (50) stands upright near one end of the windward row section (30) on the first side face (23a) side. The second header collecting pipe (60) is provided upright in the vicinity of the other end on the fourth side face (23d) side of the windward row (30). The third header collecting pipe (70) stands upright near one end of the leeward row section (40) on the first side face (23a) side. The fourth header collecting pipe (80) is erected near the other end of the leeward row part (40) on the fourth side face part (23d) side. The first branch unit (91) is erected near the first header collecting pipe (50). The second branch unit (92) stands upright near the third header collecting pipe (70).

    Flat tubes (31, 41), fins (32, 42), first header manifold (50), second header manifold (60), third header manifold (70), fourth header manifold (80) , The first branch unit (91) and the second branch unit (92) are members made of an aluminum alloy, and are joined to each other by brazing.

(Windward row)
As shown in FIGS. 2, 3, and 5 to 10, the windward row portion (30) includes a number of flat tubes (31) and a number of fins (32).

    The flat tube (31) is a heat transfer tube whose cross section perpendicular to the axis has a flat, substantially elliptical shape (see FIG. 7). The plurality of flat tubes (31) are arranged such that upper and lower flat portions face each other. That is, the plurality of flat tubes (31) are arranged one above the other with a certain interval between them, and the respective cylinder axes are substantially parallel.

    As shown in FIG. 2, the flat tube (31) includes a first windward tube portion (31a) along the first side surface portion (23a) and a second windward tube portion along the second side surface portion (23b). (31b), a third upwind pipe section (31c) along the third side section (23c), and a fourth upwind pipe section (31d) along the fourth side section (23d). ing. As shown in FIG. 2, the flat tube (31) has a first windward bend in which the first windward pipe portion (31a) is bent inward at a substantially right angle horizontally and inward with respect to the second windward pipe portion (31b). Part (33a), a second windward bent part (33b) for bending the third windward pipe part (31c) horizontally inward at a substantially right angle with respect to the second windward pipe part (31b), and a third wind A third windward bent portion (33c) is provided to bend the fourth windward pipe portion (31d) inward at a substantially right angle horizontally inward with respect to the upper pipe portion (31c).

    In each flat tube (31), the end of the first windward pipe portion (31a) is inserted into the first header collecting pipe (50) (see FIG. 5), and the end of the fourth windward pipe portion (31d). The part is inserted into the second header collecting pipe (60) (see FIG. 6).

    As shown in FIG. 7, a plurality of refrigerant channels (C) are formed in each flat tube (31). The plurality of refrigerant passages (C) are passages extending in the cylinder axis direction of the flat tube (31), and are arranged in a line in the width direction (the air passage direction) of the flat tube (31). Each refrigerant channel (C) is open at both end surfaces of the flat tube (31). The refrigerant supplied to the windward row part (30) exchanges heat with air while flowing through the refrigerant flow path (C) of the flat tube (31). The plurality of refrigerant flow paths (C) of each flat tube (31) of the windward row part (30) constitute a windward refrigerant flow path group (C1).

    As shown in FIG. 7, the fin (32) is a vertically long plate-like fin formed by pressing a metal plate. The plurality of fins (32) are arranged at regular intervals in the axial direction of the flat tube (31). The fin (32) is formed with a large number of elongated notches (32a) extending from the outer edge of the fin (32) (ie, the edge on the windward side) in the width direction of the fin (32). In the fin (32), a number of notches (32a) are formed at regular intervals in the longitudinal direction (up-down direction) of the fin (32). The windward portion of the notch (32a) forms a tube insertion portion (32b). The flat tube (31) is inserted into the tube insertion portion (32b), and is joined to the periphery of the tube insertion portion (32b) by brazing. Further, a louver (32c) for promoting heat transfer is formed in the fin (32).

    As shown in FIG. 3, two heat exchange regions (35, 37) are formed vertically on the windward row (30). The upper heat exchange area constitutes the windward main heat exchange area (35), and the lower heat exchange area constitutes the windward auxiliary heat exchange area (37). The number of flat tubes (31) corresponding to the windward auxiliary heat exchange region (37) is smaller than the number of flat tubes (31) forming the windward main heat exchange region (35).

    The upwind main heat exchange area (35) is divided into six upwind main heat exchange sections (36) arranged vertically. The upwind auxiliary heat exchange area (37) is divided into six upwind auxiliary heat exchange sections (38) arranged vertically. That is, the windward main heat exchange area (35) and the windward auxiliary heat exchange area (37) are each divided into the same number of heat exchange sections. The number of the windward main heat exchange section (36) and the windward auxiliary heat exchange section (38) is merely an example, and is preferably plural.

    As shown in FIGS. 3 and 6, each windward main heat exchange section (36) is provided with the same number (for example, 6) of flat tubes (31). The number of flat tubes (31) provided in each windward main heat exchange section (36) is merely an example, and may be plural or one.

    As shown in FIGS. 3 and 5, each windward auxiliary heat exchange unit (38) is provided with the same number (for example, two) of flat tubes (31). The number of flat tubes (31) provided in each windward auxiliary heat exchange section (38) is merely an example, and may be plural or one.

(Leeward row)
As shown in FIGS. 2, 4, 5 to 10, the leeward row portion (40) includes a number of flat tubes (41) and a number of fins (42).

    The flat tube (41) is a heat transfer tube whose cross section perpendicular to the axis has a flat, substantially elliptical shape (see FIG. 7). The plurality of flat tubes (41) are arranged with upper and lower flat portions facing each other. That is, the plurality of flat tubes (41) are arranged one above the other at regular intervals, and their cylinder axes are substantially parallel.

    As shown in FIG. 2, the flat tube (41) has a first leeward pipe portion (41a) along the inner edge of the first leeward pipe portion (31a) and an inner edge of the second leeward pipe portion (31b). Along the second leeward pipe section (41b), the third leeward pipe section (41c) along the inner edge of the third leeward pipe section (31c), and along the inner edge of the fourth leeward pipe section (31d). And a fourth leeward pipe section (41d). The flat tube (41) includes a first leeward bent portion (43a) for bending the first leeward tube portion (41a) horizontally and inward at a substantially right angle with respect to the second leeward tube portion (41b), and a second leeward tube. A second leeward bent portion (43b) for bending the third leeward tube portion (41c) horizontally inward at a substantially right angle with respect to the portion (41b); and a fourth leeward tube portion for the third leeward tube portion (41c). A third leeward bent portion (43c) for bending (41d) horizontally inward at a substantially right angle is provided.

    In each flat tube (41), the end of the first leeward pipe (41a) is inserted into the third header collecting pipe (70), and the end of the fourth leeward pipe (41d) is connected to the fourth header collecting pipe (41). 80) (see FIG. 4).

    As shown in FIGS. 7 to 10, a plurality of refrigerant channels (C) are formed in each flat tube (41). The plurality of refrigerant channels (C) are passages extending in the cylinder axis direction of the flat tube (41), and are arranged in a line in the width direction of the flat tube (41) (the direction in which air passes). Each refrigerant channel (C) is open at both end surfaces of the flat tube (41). The refrigerant supplied to the leeward row (40) exchanges heat with air while flowing through the refrigerant flow path (C) of the flat tube (41). The plurality of refrigerant channels (C) of each flat tube (41) of the leeward row (40) constitute a leeward refrigerant channel group (C2).

    As shown in FIG. 7, the fin (42) is a vertically long plate-like fin formed by pressing a metal plate. The plurality of fins (42) are arranged at regular intervals in the axial direction of the flat tube (41). The fin (42) has a large number of elongated notches (42a) extending in the width direction of the fin (42) from the outer edge of the fin (42) (that is, the edge on the windward side). In the fin (42), a large number of notches (42a) are formed at regular intervals in the longitudinal direction (up-down direction) of the fin (42). The windward portion of the notch (42a) forms a tube insertion portion (42b). The flat tube (41) is inserted into the tube insertion portion (42b), and is joined to the periphery of the tube insertion portion (42b) by brazing. The fin (42) is formed with a louver (42c) for promoting heat transfer.

    As shown in FIG. 4, two heat exchange regions (45, 47) are formed vertically on the leeward row (40). The upper heat exchange region constitutes a leeward main heat exchange region (45), and the lower heat exchange region constitutes a leeward auxiliary heat exchange region (47). The number of flat tubes (41) corresponding to the leeward auxiliary heat exchange region (47) is smaller than the number of flat tubes (41) constituting the leeward main heat exchange region (45).

    The leeward main heat exchange area (45) is divided into six leeward main heat exchange sections (46) arranged vertically. The leeward auxiliary heat exchange area (47) is divided into six leeward auxiliary heat exchange units (48) arranged vertically. That is, the leeward main heat exchange area (45) and the leeward auxiliary heat exchange area (47) are each divided into the same number of heat exchange sections. The number of the leeward main heat exchange units (46) and the number of the leeward auxiliary heat exchange units (48) are merely examples, and are preferably plural.

    As shown in FIG. 4, each leeward main heat exchange part (46) is provided with the same number (for example, six) of flat tubes (41). The number of flat tubes (41) provided in each leeward main heat exchange section (46) is merely an example, and may be plural or one.

    As shown in FIGS. 5 and 6, each leeward auxiliary heat exchange section (48) is provided with the same number (for example, two) of flat tubes (41). The number of flat tubes (41) provided in each leeward auxiliary heat exchange section (48) is merely an example, and may be plural or one.

[Third header collecting pipe]
As shown in FIGS. 2 and 4, the third header collecting pipe (70) is a cylindrical member whose upper and lower ends are closed. The length (height) of the third header collecting pipe (70) substantially matches the height of the leeward row portion (30) and the leeward row portion (40).

    The internal structure of the third header collecting pipe (70) is the same as that of the first header collecting pipe (50) shown in FIG. That is, as shown in FIG. 4, the internal space of the third header collecting pipe (70) is vertically divided by the main partition (71). The space above the main partition (71) is a leeward upper space (72) corresponding to the leeward main heat exchange area (45). The space below the main partition (81) is a leeward space (73) corresponding to the leeward auxiliary heat exchange area (47). One end of one second main gas pipe (72a) is connected to a vertically intermediate portion of the leeward upper space (72). The other end of the second main gas pipe (72a) communicates with the gas side communication pipe (14).

    The leeward space (73) is divided into six leeward auxiliary spaces (75) by five partition plates (74) arranged vertically at equal intervals. These six downwind auxiliary spaces (75) respectively correspond to the six downwind auxiliary heat exchange sections (48). For example, a first leeward pipe portion (41a) of two flat tubes (41) communicates with each leeward auxiliary space (75).

[Fourth header collecting pipe]
As shown in FIG. 2, FIG. 4, and FIG. 8 to FIG. 10, the fourth header collecting pipe (80) is a cylindrical member whose upper and lower ends are closed. The length (height) of the fourth header collecting pipe (80) is substantially the same as the height of the leeward row portion (30) and the leeward row portion (40).

    The internal structure of the fourth header collecting pipe (80) is the same as that of the second header collecting pipe (60) shown in FIG. That is, as shown in FIG. 4, the internal space of the fourth header collecting pipe (80) is vertically divided by the main partition (81). The space above the main partition (81) is a leeward upper space (82) corresponding to the leeward main heat exchange area (45). The space below the main partition (81) is a leeward space (83) corresponding to the leeward auxiliary heat exchange area (47).

    The leeward upper space (82) is partitioned into six leeward main communication spaces (85) by five partition plates (84) arranged at equal intervals up and down. Each of the six leeward main communication spaces (85) corresponds to one of the six leeward main heat exchange sections (46). The leeward main communication space (85) is in communication with, for example, first leeward pipe portions (41a) of six flat tubes (41).

    The leeward space (83) is divided into six leeward auxiliary communication spaces (87) by five partition plates (86) arranged at equal intervals in the vertical direction. These six downwind auxiliary communication spaces (87) respectively correspond to the six downwind auxiliary heat exchange sections (48). For example, each fourth leeward pipe section (41d) of two flat pipes (41) communicates with each leeward auxiliary communication space (87).

    Six leeward communication pipes (88) are connected to the fourth header collecting pipe (80). The leeward communication pipe (88) is the end of the flat pipe (41) in the leeward main heat exchange area (45) of the leeward row section (40) and the end of the flat pipe (41) in the leeward auxiliary heat exchange area (47). And are connected.

    Specifically, the first leeward communication pipe (88) connects the uppermost leeward auxiliary communication space (87) and the lowermost leeward main communication space (85), and the second leeward communication pipe (88). ) Connects the second leeward auxiliary communication space (87) from the top and the second leeward main communication space (85) from the bottom, and the third leeward communication pipe (88) is three-stage from the top The leeward auxiliary communication space (87) is connected to the third leeward main communication space (85) from the bottom. The fourth leeward communication pipe (88) connects the fourth leeward auxiliary communication space (87) with the fourth leeward main communication space (85) from the top, and a fifth leeward communication pipe (88). 88) connects the fifth leeward auxiliary communication space (87) from the top and the fifth leeward main communication space (85) from the bottom, and the sixth leeward communication pipe (88) The leeward auxiliary communication space (87) is connected to the uppermost leeward main communication space (85).

[First branch unit]
As shown in FIGS. 2 and 3, the first branch unit (91) is attached to the first header collecting pipe (50). The first branch unit (91) has a cylindrical portion (91a), six liquid-side connection pipes (91b), and one first main liquid pipe (91c).

    The cylindrical portion (91a) is formed in a cylindrical shape lower than the first header collecting pipe (50), and stands upright along a lower portion of the first header collecting pipe (50). The six liquid-side connection pipes (91b) are arranged vertically and connected to the cylindrical portion (91a). The number of each liquid side connection pipe (91b) is the same as the number of the windward auxiliary communication spaces (67) (six in this example). Each liquid-side connection pipe (91b) is in communication with each of the windward auxiliary communication spaces (67). One end of the first main liquid pipe (91c) is connected to a lower part of the cylindrical portion (91a). The first main liquid pipe (91c) and each liquid-side connection pipe (91b) communicate with each other via the internal space of the cylindrical portion (91a).

[Second branch unit]
As shown in FIGS. 2 and 4, the second branch unit (92) is attached to the third header collecting pipe (70). The second branch unit (92) has a cylindrical portion (92a), six liquid-side connection pipes (92b), and one second main liquid pipe (92c).

    The cylindrical portion (92a) is formed in a cylindrical shape lower than the third header collecting pipe (70), and stands up along a lower portion of the third header collecting pipe (70). The six liquid-side connection pipes (92b) are arranged vertically and connected to the cylindrical portion (92a). The number of each liquid side connection pipe (92b) is the same as the number of the leeward auxiliary spaces (75) (six in this example). Each liquid-side connection pipe (92b) is in communication with each leeward auxiliary space (75). One end of the second main liquid pipe (92c) is connected to a lower part of the cylindrical portion (92a). The second main liquid pipe (92c) and each liquid side connection pipe (92b) communicate with each other via the internal space of the cylindrical portion (92a).

(Liquid branch pipe)
As schematically shown in FIG. 2, the first main liquid pipe (91c) of the first branch unit (91) and the second main liquid pipe (92c) of the second branch unit (92) include a liquid branch pipe. (28) is connected. The liquid branch pipe (28) bifurcates and communicates with each of the flow dividing units (91, 92) and each of the auxiliary spaces (55, 75). That is, the liquid branch pipe (28) is connected to the other end (the first windward pipe part (31a)) of each flat pipe (31) of the leeward row part (30) and the flattened pipe part (31a) of the leeward row part (40). The other end of the pipe (41) (the first leeward pipe section (41a)) is branched and communicated.

(Gas branch pipe)
As schematically shown in FIG. 2, a gas branch pipe (52a) in the leeward row (30) and a second main gas pipe (72a) in the leeward row (40) have a gas branch pipe (72). 29) is connected. The gas branch pipe (29) bifurcates and communicates with the upwind space (52) and the downwind space (72). That is, the gas branch pipe (29) includes the other end (the first leeward pipe section (31a)) of the leeward row section (30) and the other end (the first leeward pipe section) of the leeward row section (40). (41a)).

-Refrigerant flow in outdoor heat exchanger-
When functioning as a condenser and an evaporator, the outdoor heat exchanger (23) is provided with a refrigerant flowing through each flat tube (31) of the leeward row (30) and a flat tube (41) of the leeward row (40). ) Is configured to be parallel to the refrigerant flowing therethrough. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( 40) the refrigerant flows in parallel with the flat tubes (41) in the leeward main heat exchange area (45), and the flat tubes (31) in the leeward auxiliary heat exchange area (47) in the leeward row (30); The refrigerant is configured to flow in parallel with the flat tube (41) of the leeward auxiliary heat exchange area (47) of the leeward row (40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) And the refrigerant flowing through the leeward refrigerant flow path group (C2) are configured to flow in parallel with each other.

    Further, when the outdoor heat exchanger (23) functions as a condenser and an evaporator, the outdoor heat exchanger (23) has a refrigerant flowing through each flat tube (31) of the leeward row (30) and a flat tube (40) of the leeward row (40). 41) and the refrigerant flowing in the same direction. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( Refrigerant flows in the same direction with the flat tube (41) in the leeward auxiliary heat exchange area (47) in 40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) Flows through the leeward refrigerant flow path group (C2) in the same direction.

[Refrigerant flow in the case of a condenser]
During the cooling operation of the air conditioner (10), the indoor heat exchanger (25) functions as an evaporator, and the outdoor heat exchanger (23) functions as a condenser. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the cooling operation will be described.

    In the outdoor heat exchanger (23), the gas refrigerant discharged from the compressor (21) flows into the gas branch pipe (29), and the first main gas pipe (52a) and the second main gas pipe (72a). And divert to

    As shown in FIG. 3, the refrigerant supplied to the first main gas pipe (52a) flows into the windward upstream space (52) of the first header collecting pipe (50), and flows into each windward main heat exchange section (52). 36). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind main heat exchange section (36) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each of the windward main communication spaces (65) of the second header collecting pipe (60), and flows into each of the windward communication pipes (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and is distributed to each windward auxiliary heat exchange unit (38). You. Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) further radiates heat to air and condenses, and the supercooled state (ie, (Liquid single phase state).

    The supercooled liquid refrigerant is supplied to each windward auxiliary space (55) of the first header collecting pipe (50) and merges in the first branch unit (91) to form the first main liquid pipe (91c). Flows through.

    As shown in FIG. 4, the refrigerant supplied to the second main gas pipe (72a) flows into the leeward upper space (72) of the third header collecting pipe (70), and flows into the leeward main heat exchange section (46). Be distributed. Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and is distributed to each leeward auxiliary heat exchange unit (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) further radiates heat to the air to be condensed, and becomes a supercooled state (that is, Phase state).

    The liquid refrigerant in the supercooled state is supplied to each leeward auxiliary space (75) of the third header collecting pipe (70), merges in the second branch unit (92), and flows through the second main liquid pipe (92c). Flows.

    The refrigerant flowing through the first main liquid pipe (91c) and the refrigerant flowing through the second main liquid pipe (92c) merge at the liquid branch pipe (28) and are sent to the liquid side communication pipe (13).

(Temperature change of refrigerant and air in case of condenser)
FIG. 11 shows an example of temperature changes of air and refrigerant in the outdoor heat exchanger (23) functioning as a condenser.

    The gas refrigerant in a superheated state at 70 ° C. flows into the flat tube (31) of the windward main heat exchange area (35). This refrigerant becomes a 50 ° C. saturated gas refrigerant in the middle of the upstream refrigerant flow path group (C1) of the flat tubes (31) in the upstream main heat exchange area (35), and then gradually condenses. The refrigerant flowing out of the windward main heat exchange area (35) flows into the flat tube (31) of the windward auxiliary heat exchange area (37). This refrigerant becomes a liquid-phase single-phase saturated refrigerant (saturation temperature: 50 ° C.) in the upwind refrigerant flow path group (C1) of the flat tube (31) in the windward auxiliary heat exchange area (37), and then further radiates heat. To a supercooled state (for example, 42 ° C.).

    The gas refrigerant in a superheated state at 70 ° C. flows into the flat tube (41) in the leeward main heat exchange area (45). This refrigerant becomes a 50 ° C. saturated gas refrigerant in the leeward refrigerant flow path group (C2) of the flat tube (41) in the leeward main heat exchange area (45), and then gradually condenses. The refrigerant flowing out of the leeward main heat exchange area (45) flows into the flat tube (41) of the leeward auxiliary heat exchange area (47). This refrigerant becomes a liquid-phase single-phase saturated refrigerant (saturation temperature: 50 ° C.) in the leeward refrigerant flow path group (C2) of the flat tubes (41) in the leeward auxiliary heat exchange area (47), and then further radiates heat and becomes excessive. It will be in a cooling state (for example, 47 ° C.).

    On the other hand, for example, air at 35 ° C. flows into the leeward main heat exchange area (35) and the leeward auxiliary heat exchange area (37). The 45 ° C air heated in the leeward main heat exchange area (35) flows into the leeward main heat exchange area (45), and the leeward auxiliary heat exchange area (37) flows into the leeward auxiliary heat exchange area (37). When passing through (35), heated 40 ° C. air flows in.

    As described above, when the outdoor heat exchanger (23) functions as a condenser, the temperature of the refrigerant in the entire outdoor heat exchanger (23) becomes higher than the temperature of the air, and the amount of heat released from the refrigerant to the air (ie, , The heat radiation of the refrigerant).

[Flow of refrigerant in evaporator]
During the heating operation of the air conditioner (10), the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the heating operation will be described.

    To the outdoor heat exchanger (23), a refrigerant that has been expanded into a gas-liquid two-phase state when passing through the expansion valve (24) is supplied through a pipe (17). The refrigerant flows into the liquid branch pipe (28), and is divided into a first main liquid pipe (91c) and a second main liquid pipe (92c).

    As shown in FIG. 12, the refrigerant supplied to the first branch unit (91) is branched to the respective liquid-side connection pipes (91b), and each of the windward auxiliary spaces (55) of the first header collecting pipe (50). The heat is further distributed to each windward auxiliary heat exchange section (38). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) absorbs heat from air and evaporates. Then, each refrigerant is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and flows into each windward communication pipe (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward main communication space (65) of the second header collecting pipe (60), and is distributed to each windward main heat exchange unit (36). You. Each refrigerant passing through each windward refrigerant flow path group (C1) of each flat tube (31) of each windward main heat exchange section (36) further absorbs heat from the air and evaporates, and the superheated state (that is, gas) (Single-phase state).

    The superheated gas refrigerant joins in the space on the windward side (52) of the first header collecting pipe (50), and is sent from the first main gas pipe (52a) to the gas-side communication pipe (14).

    As shown in FIG. 13, the refrigerant supplied to the second branch unit (92) is diverted to each liquid-side connection pipe (92b), and from each leeward auxiliary space (75) of the third header collecting pipe (70). It is distributed to each downwind auxiliary heat exchange section (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) absorbs heat from air and evaporates. Thereafter, each refrigerant is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and is distributed to each leeward main heat exchange section (46). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) further absorbs heat from air and evaporates, and is overheated (ie, gas single phase). State).

    The superheated gas refrigerant joins in the leeward space (72) of the third header collecting pipe (70) and flows through the second main gas pipe (72a).

    The refrigerant flowing through the first main gas pipe (52a) and the refrigerant flowing through the second main gas pipe (72a) merge at the gas branch pipe (29) and are sent to the gas side communication pipe (14).

(Temperature change of refrigerant and air in case of evaporator)
An example of the temperature change of the air and the refrigerant in the outdoor heat exchanger (23) functioning as an evaporator will be described with reference to FIG.

    A refrigerant in a gas-liquid two-phase state having a saturation temperature of 1.5 ° C. flows into the flat tube (31) of the windward auxiliary heat exchange area (37). In the flat tube (31) of the windward auxiliary heat exchange area (37), the saturation temperature of the refrigerant becomes about 0.5 ° C due to the pressure loss when the refrigerant passes through the windward refrigerant flow path group (C1). It gradually decreases until.

    The gas-liquid two-phase refrigerant flowing out of the windward auxiliary heat exchange area (37) flows into the flat tube (41) of the windward main heat exchange area (35). In the flat tube (31) of the windward main heat exchange area (35), the saturation temperature of the refrigerant further decreases due to pressure loss when the refrigerant passes through the windward refrigerant flow path group (C1) (for example, 0 ° C). The refrigerant enters a gas single-phase state in the middle of the flat tube (31) in the windward main heat exchange region (35), and after its temperature rises to 1 ° C, the flat tube in the windward main heat exchange region (35). Outflow from (31).

    A refrigerant in a gas-liquid two-phase state having a saturation temperature of 1.5 ° C. flows into the flat tube (41) of the leeward auxiliary heat exchange area (47). In the flat tube (41) of the leeward auxiliary heat exchange area (47), due to the pressure loss when the refrigerant passes through the leeward refrigerant flow path group (C2), the saturation temperature of the refrigerant gradually increases to about 0.5 ° C. descend.

    A refrigerant in a gas-liquid two-phase state having a saturation temperature of 1.5 ° C. flows into the flat tube (41) of the leeward auxiliary heat exchange area (47). In the flat tube (41) of the leeward auxiliary heat exchange area (47), due to the pressure loss when the refrigerant passes through the leeward refrigerant flow path group (C2), the saturation temperature of the refrigerant gradually increases to about 0.5 ° C. descend.

    The gas-liquid two-phase refrigerant flowing out of the leeward auxiliary heat exchange area (47) flows into the flat tube (41) in the leeward main heat exchange area (45). In the flat tube (41) of the leeward main heat exchange area (45), the saturation temperature of the refrigerant further decreases due to the pressure loss when the refrigerant passes through the leeward refrigerant flow path group (C2) (for example, about 0). ° C). This refrigerant enters a gas single-phase state in the middle of the flat tube (41) in the leeward main heat exchange region (45), and after its temperature rises to 1 ° C., the flat tube (41) in the leeward main heat exchange region (45). ).

    On the other hand, air at, for example, 7 ° C. flows into the windward auxiliary heat exchange area (37) and the windward main heat exchange area (35). Further, the air cooled at 3 ° C., which is cooled when passing through the leeward auxiliary heat exchange area (37), flows into the leeward auxiliary heat exchange area (47). Cooled 2 ° C. air flows in as it passes through the upper main heat exchange zone (35).

    As described above, when the outdoor heat exchanger (23) functions as an evaporator, the temperature of the refrigerant in the entire outdoor heat exchanger (23) becomes lower than the temperature of the air, and the amount of heat ( That is, the amount of heat absorbed by the refrigerant) is secured.

[Pressure loss reduction effect]
As described above, in the present embodiment, in both the case where the outdoor heat exchanger (23) functions as a condenser and the case where the outdoor heat exchanger functions as an evaporator, the refrigerant is connected to the leeward refrigerant flow path group (C1) and the leeward. It flows in parallel with the refrigerant flow path group (C2).

For example, in a configuration (comparative example) in which the refrigerant flows in series through the two refrigerant flow path groups (C1, C2), the flow velocity of the refrigerant flowing through each flat tube (31, 41) is twice that of the present embodiment, and the refrigerant flow The total length of the road (C) is also doubled. The pressure loss in the refrigerant channel (C) is proportional to the square of the flow velocity, and is proportional to the total length of the refrigerant channel. Therefore, the pressure loss of the refrigerant channel (C) of the comparative example is approximately eight times (= 2 × 2 ² ) that of the present embodiment. That is, in the present embodiment, the refrigerant is caused to flow in parallel through the refrigerant flow path group (C1) of the leeward row (30) and the refrigerant flow path group (C2) of the leeward row (40). The pressure loss in the refrigerant channel (C) can be reduced to 1/8 as compared with the example.

    When the pressure loss of the refrigerant can be reduced in this way, it is possible to prevent a decrease in the pressure of the refrigerant in, for example, the outdoor heat exchanger (23) of the evaporator. That is, in the outdoor heat exchanger (23) of the evaporator, since the amount of decrease in the pressure of the refrigerant due to the pressure loss can be reduced, the pressure difference between the inlet and the outlet of the outdoor heat exchanger (23) (that is, the compressor ( The difference between the suction pressure of 21) and the pressure of the refrigerant flowing into the outdoor heat exchanger (23)) can be reduced. As a result, when the suction pressure of the compressor (21) is set to a predetermined value, the evaporation pressure of the refrigerant flowing into the outdoor heat exchanger (23) and, consequently, the evaporation temperature can be reduced as compared with the comparative example. Thereby, in the outdoor heat exchanger (23), the difference between the temperature of the refrigerant flowing through the refrigerant flow path group (C1) in the windward row (30) and the temperature of the air passing through the windward row (30) can be increased. In addition, the evaporation capacity of the outdoor heat exchanger (23) can be improved.

-Effects of Embodiment 1-
In the first embodiment, the following operations and effects can be obtained.

    Since the refrigerant flows in parallel in the flat tubes (31, 41) of each row (30, 40), the pressure loss of the refrigerant flowing through the refrigerant flow path (C) of each flat tube (31, 41) is greatly reduced. Can be reduced to As a result, a desired heat exchange efficiency can be obtained while suppressing an increase in power due to an increase in pressure loss.

    Since it is not necessary to lengthen the flat tubes (31, 41) in the width direction, the bending process of the flat tubes (31, 41) of each row portion (30, 40) becomes easy. Thereby, the flat tubes (31, 41) of each row portion (30, 40) can be bent to manufacture a four-sided heat exchanger, and the heat exchanger can be made compact.

    As shown in FIG. 2, a liquid branch pipe (28) and a gas branch pipe (29) for flowing the refrigerant in parallel to the respective row portions (30, 40) can be arranged collectively. Thereby, the space of the piping can be made compact, or the installation of the piping can be facilitated.

  In addition, by reducing the width of each flat tube (31, 41), the ventilation resistance between the flat tubes (31, 41) in each row (30, 40) can be reduced, and the decrease in heat transmittance is suppressed. it can. Furthermore, since the width of the flat tubes (31, 41) is reduced, it is possible to prevent dew condensation water from staying above the flat tubes (31, 41). As a result, frost formation on the surfaces of the flat tubes (31, 41) can be prevented.

<< Embodiment 2 >>
The air conditioner (10) of the second embodiment differs from the first embodiment in the configuration of the outdoor heat exchanger (23). In the outdoor heat exchanger (23) of the second embodiment, the configuration of the upwind row section (30) is the same as that of the first embodiment. Hereinafter, differences from the first embodiment will be described with reference to FIGS.

    In the second embodiment, the third header collecting pipe (70) is provided upright in the vicinity of one end of the leeward row (40) on the side of the fourth side surface (23d). The fourth header collecting pipe (80) is erected near the other end of the leeward row (40) on the first side face (23a) side. That is, in the second embodiment, the positions of the third header collecting pipe (70) and the fourth header collecting pipe (80) in the first embodiment are completely opposite in the longitudinal direction of the flat tubes (31, 41). ing. In the vicinity of the third header collecting pipe (70), as in the first embodiment, it stands upright near the second branch unit (92).

    The first main gas pipe (52a) and the second main gas pipe (72a) communicate with the gas side communication pipe (14) via a branch pipe (not shown). The first main liquid pipe (91c) and the second main liquid pipe (92c) communicate with the liquid side communication pipe (13) via a branch pipe (not shown).

-Refrigerant flow in outdoor heat exchanger-
As shown in FIGS. 16 to 19, when the outdoor heat exchanger (23) functions as a condenser and an evaporator, the outdoor heat exchanger (23) has a refrigerant flowing through each flat tube (31) of the windward row (30) and a leeward row. The refrigerant flowing through each flat tube (41) of the section (40) is configured to be parallel. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( 40) the refrigerant flows in parallel with the flat tubes (41) in the leeward main heat exchange area (45), and the flat tubes (31) in the leeward auxiliary heat exchange area (47) in the leeward row (30); The refrigerant is configured to flow in parallel with the flat tube (41) of the leeward auxiliary heat exchange area (47) of the leeward row (40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) And the refrigerant flowing through the leeward refrigerant flow path group (C2) are configured to flow in parallel with each other.

    Further, when the outdoor heat exchanger (23) functions as a condenser and an evaporator, the outdoor heat exchanger (23) has a refrigerant flowing through each flat tube (31) of the leeward row (30) and a flat tube (40) of the leeward row (40). 41) and the refrigerant flowing therethrough is configured to be in opposite directions to each other. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( Refrigerant flows in opposite directions to the flat tube (41) of the leeward auxiliary heat exchange area (47) of 40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) And the refrigerant flowing through the leeward refrigerant flow path group (C2) flow in opposite directions.

[In case of condenser]
During the cooling operation of the air conditioner (10), the indoor heat exchanger (25) functions as an evaporator, and the outdoor heat exchanger (23) functions as a condenser. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the cooling operation will be described.

    The gas refrigerant discharged from the compressor (21) is supplied to the outdoor heat exchanger (23) through the pipe (18). This refrigerant flows from the pipe (18) to the first main gas pipe (52a) and the second main gas pipe (82a).

    As shown in FIG. 16, the refrigerant supplied to the first main gas pipe (52a) flows into the upwind space (52) of the first header collecting pipe (50), and flows into each of the upwind main heat exchange sections (52). 36). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind main heat exchange section (36) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each of the windward main communication spaces (65) of the second header collecting pipe (60), and flows into each of the windward communication pipes (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and is distributed to each windward auxiliary heat exchange unit (38). You. Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) further radiates heat to air and condenses, and the supercooled state (ie, (Liquid single phase state).

    The supercooled liquid refrigerant is supplied to each windward auxiliary space (55) of the first header collecting pipe (50) and merges in the first branch unit (91) to form the first main liquid pipe (91c). It is sent to the liquid side connection pipe (13).

    As shown in FIG. 17, the refrigerant supplied from the pipe (18) to the second main gas pipe (72a) flows into the leeward upper space (72) of the third header collecting pipe (70), and the leeward main heat exchange is performed. Distributed to the department (46). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and is distributed to each leeward auxiliary heat exchange unit (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) further radiates heat to the air to be condensed, and becomes a supercooled state (that is, Phase state).

    The supercooled liquid refrigerant is supplied to each leeward auxiliary space (75) of the third header collecting pipe (70), merges in the second branch unit (92), and flows out of the first branch unit (91). The refrigerant is sent to the liquid-side communication pipe (13) together with the refrigerant.

[In case of evaporator]
During the heating operation of the air conditioner (10), the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the heating operation will be described.

    To the outdoor heat exchanger (23), a refrigerant that has been expanded into a gas-liquid two-phase state when passing through the expansion valve (24) is supplied through a pipe (17). This refrigerant is split from the pipe (17) into the first split unit (91) and the second split unit (92).

    As shown in FIG. 18, the refrigerant supplied to the first branch unit (91) is diverted to the respective liquid side connection pipes (91b), and each leeward auxiliary space (55) of the first header collecting pipe (50). The heat is further distributed to each windward auxiliary heat exchange section (38). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) absorbs heat from air and evaporates. Then, each refrigerant is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and flows into each windward communication pipe (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward main communication space (65) of the second header collecting pipe (60), and is distributed to each windward main heat exchange unit (36). You. Each refrigerant passing through each windward refrigerant flow path group (C1) of each flat tube (31) of each windward main heat exchange section (36) further absorbs heat from the air and evaporates, and the superheated state (that is, gas) (Single-phase state).

    The superheated gas refrigerant joins in the space on the windward side (52) of the first header collecting pipe (50), and is sent from the first main gas pipe (52a) to the gas-side communication pipe (14).

    As shown in FIG. 19, the refrigerant supplied to the second branch unit (92) is diverted to the respective liquid side connection pipes (92b) and from the respective leeward auxiliary spaces (75) of the third header collecting pipe (70). It is distributed to each downwind auxiliary heat exchange section (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) absorbs heat from air and evaporates. Thereafter, each refrigerant is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and is distributed to each leeward main heat exchange section (46). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) further absorbs heat from air and evaporates, and is overheated (ie, gas single phase). State).

    The superheated gas refrigerant joins in the leeward space (72) of the third header collecting pipe (70) and is sent to the gas side connecting pipe (14) together with the refrigerant flowing out of the first main gas pipe (52a). Can be

<Measures to suppress air drift>
By the way, when the outdoor heat exchanger (23) functions as an evaporator, there has conventionally been a problem that the air flowing through the outdoor heat exchanger (23) tends to drift. Specifically, in the outdoor heat exchanger (23), the refrigerant flow path groups (C1, C2) are respectively formed in the two row portions (30, 40), and the refrigerant flow path groups (C1, C2) are formed in parallel. Let the refrigerant flow. Here, in each of the refrigerant flow path groups (C1, C2), the refrigerant in the gas-liquid two-phase state is used for cooling air. For this reason, moisture in the air may condense and form frost on the surfaces of the flat tubes (31, 41) and the fins (32, 42).

    On the other hand, in each of the refrigerant flow path groups (C1, C2), when the refrigerant in the gas-liquid two-phase state further evaporates, it becomes overheated and the temperature rises. Therefore, in the flat tubes (31, 41), in the portion where the superheated refrigerant flows, moisture in the air is less likely to condense, and frost forms on the surfaces of the flat tubes (31, 41) and the fins (32, 42). Hardly occurs.

    For this reason, in the adjacent refrigerant flow path groups (C1, C2), the part where the refrigerant in the liquid state or the gas-liquid two-phase state flows and the part where the superheated refrigerant flows overlap in the air passage direction. This causes a problem that the air flowing through the outdoor heat exchanger (23) tends to drift.

    Specifically, in the adjacent refrigerant flow path groups (C1, C2), for example, when a portion in which a refrigerant in a liquid state or a gas-liquid two-phase state flows overlaps in a direction in which air passes, each flat tube ( 31, 41) and the surface of each fin (32, 42), frost formation is likely to occur as described above. In particular, in the case of the flat tubes (31, 41), the amount of frost tends to increase because the water condensed on the surface tends to stay on the surfaces. In such a state, the flat tubes (31, 41) and the fins (32, 42) of both the leeward row portion (30) and the leeward row portion (40) are continuously frosted, so Tends to increase the ventilation resistance.

    On the other hand, in the adjacent refrigerant flow path groups (C1, C2), when the portions of the superheated region where the refrigerant flows overlap in the air passage direction, the flat tubes (31, 41) and the fins (32, Frost formation hardly occurs on the surface of 42). Therefore, in such a state, there is a problem in that the ventilation resistance of the portion corresponding to the overheated region overlapping in two rows is smaller than that of the other portion, and the air tends to drift to this portion.

    In this way, when air drift occurs, the flat tubes (31, 41) and fins (32, 42) of the entire outdoor heat exchanger (23) cannot be effectively used for heat transfer between the refrigerant and the air, This leads to a decrease in heat exchange efficiency. Therefore, in the present embodiment, in order to prevent such a drift of the air, the superheated regions (S1, S2) of the respective row portions (30, 40) are prevented from overlapping in the air passage direction.

    That is, as shown in FIGS. 19 to 21, in the outdoor heat exchanger (23), as described above, the refrigerant flowing through the leeward refrigerant flow path group (C1) and the leeward refrigerant flow path group (C2) flow The refrigerant and the refrigerant are in opposite directions. For this reason, the superheated area (S1) of the leeward row (30) is formed near the end of the first leeward pipe (31a) of the flat tube (31), and the overheated area of the leeward row (40) is formed. (S2) is formed near the end of the fourth leeward pipe section (41d) of the flat pipe (41). That is, the superheated area (S1) and the superheated area (S2) are located farthest in the longitudinal direction of each flat tube (31, 41). Therefore, it is possible to reliably prevent the superheated region (S1) and the superheated region (S2) from overlapping in the air passage direction, and to prevent the above-described air drift.

    In the outdoor heat exchanger (23), the number and size of the flat tubes (31, 41) and each refrigerant flow are set so that the superheated area (S1) and the superheated area (S2) do not overlap in the air passage direction. Various parameters such as the number and size of the road (C), the amount of circulating refrigerant, and the amount of air flow are designed.

-Effects of Embodiment 2-
Also in the second embodiment, similarly to the first embodiment, the pressure loss of the refrigerant can be reduced.

    As shown in FIGS. 18 to 20, when the outdoor heat exchanger (23) functions as an evaporator, it is possible to prevent the superheated regions (S1, S2) of the refrigerant from overlapping. Thereby, it is possible to suppress the air from drifting only in the superheated regions (S1, S2). As a result, even if frost forms on the surfaces of the flat tubes (31, 41) and fins (32, 42) other than the superheated areas (S1, S2), air can be uniformly flowed throughout the heat exchanger. Therefore, the heat exchange efficiency and the evaporation performance can be improved.

<< Other embodiments >>
In various embodiments of the present disclosure, the following configuration may be adopted.

    In the outdoor heat exchanger (23), the adjacent header collecting pipes (50, 70) and (60, 80) are separately formed, respectively. At least one set of these header collecting pipes is integrated, and The internal space may be divided into two rows.

    In the outdoor heat exchanger (23), the adjacent superheated regions (S1, S2) of the refrigerant flow path groups (C1, C2) of the two rows of flat tubes (31, 41) are not overlapped with each other. For example, in three or more rows of refrigerant flow path groups (C1, C2), adjacent superheated regions may not be overlapped.

    In the outdoor heat exchanger (23), the auxiliary heat exchange area (37, 47) may be omitted.

    The heat exchanger of the present disclosure is an outdoor heat exchanger (23). However, the heat exchanger of the present disclosure may be applied to the indoor heat exchanger (25). In this case, it is preferable that the indoor heat exchanger (25) is, for example, a four-sided heat exchanger mounted in an indoor unit of a ceiling embedded type or a ceiling suspended type. Further, the outdoor heat exchanger (23) and the indoor heat exchanger (25) are not necessarily four-sided and may be three or less.

    As shown in FIG. 7, for example, the heat exchanger according to the present disclosure has separate fins on the windward side and the leeward side so as to correspond to the leeward row (30) and the leeward row (40). 32, 42) are provided. However, for example, as shown in FIG. 21, the flat tubes (31, 41) are arranged in two rows in the air passage direction, while the fins (32, 42) on the windward side and the leeward side are arranged on the windward row section (30). And the leeward row portion (40).

    The fins (32, 42) of the heat exchanger of the present disclosure form a tube insertion portion (32b, 42b) at the edge on the windward side, and the flat tube (31, 41) is formed in the tube insertion portion (32b, 42b). Is inserted. However, the heat exchanger may have a configuration in which a tube insertion portion is formed at the leeward edge of the fins (32, 42), and the flat tubes (31, 41) are inserted into the tube insertion portion. Further, in the fins (32, 42) of the present disclosure, the louvers (32c, 42c) are formed as the heat transfer promoting portions, but the fins (32, 42) bulge in the thickness direction. (A convex portion) or a slit may be used as the heat transfer promoting portion.

    The two row portions (30, 40) of the above embodiment may have different configurations. That is, for example, in two rows of flat tubes (31, 41), the width of each flat tube (31, 41), the interval in the thickness direction (vertical direction) of each flat tube (31, 41), and the width of each flat tube (31, 41) The configuration may be such that the flow path area of the refrigerant flow path (C) of 41), the number of refrigerant flow paths (C) of each flat tube (31, 41), and the like are different from each other. In the two rows of fins (32, 42), the width (length in the air passing direction) of the fins (32, 42), the pitch (interval) in the thickness direction of the fins (32, 42), and the fins (32.42) ) May be different from each other.

    In the air conditioner of the present disclosure, one refrigerant adjustment valve may be provided for each of the plurality of row portions (30, 40). That is, by individually adjusting the opening degrees of these refrigerant adjustment valves, it is possible to individually adjust the amount of refrigerant flowing in parallel to each row (30, 40).

    As described above, the present invention is useful for a heat exchanger and an air conditioner.

10 Air conditioner
23 Outdoor heat exchanger (heat exchanger)
28 Liquid branch pipe
29 Gas branch pipe
30 Upwind row (row section)
31 flat tube
32 Fins
33a 1st bend (bend)
33b 2nd bend (bend)
33c 3rd bend (bend)
40 Downwind row (row section)
41 Flat tube
42 Fins
68 Upwind connecting pipe
88 Downwind connecting pipe
C refrigerant channel
S1 Overheat area
S2 Overheating area

    The present invention relates to a heat exchanger.

    BACKGROUND ART Conventionally, a heat exchanger including a number of flat tubes arranged in parallel and fins joined to the flat tubes has been known. Patent Document 1 (see FIG. 2) discloses this type of heat exchanger. This heat exchanger is a single-row heat exchanger in which flat tubes are arranged in a single row in the air passage direction. The heat exchanger has an upper heat exchange region (main heat exchange region) and a lower heat exchange region (auxiliary heat exchange region). The number of flat tubes in the lower heat exchange region is smaller than the number of flat tubes in the upper heat exchange region.

    For example, when this heat exchanger functions as an evaporator, the refrigerant in a saturated liquid state flows through the lower heat exchange region, absorbs heat from air and evaporates. This refrigerant flows through the upper heat exchange region, evaporates further, and is overheated and flows out of the heat exchanger.

JP 2012-163328 A

    By the way, in order to improve the performance of the heat exchanger as disclosed in Patent Document 1, it is conceivable to increase the length of the flat tube and increase the flow path length of the refrigerant flow path inside the flat tube. . However, if the overall length of the refrigerant flow path is increased in this way, the pressure loss when the refrigerant passes will increase.

    Further, in a heat exchanger having a large number of refrigerant flow paths formed inside a flat tube, the flow area of each refrigerant flow path is relatively small, so that the flow velocity of the refrigerant flowing through each refrigerant flow path is likely to increase. For this reason, the pressure loss of the refrigerant flowing through each refrigerant flow path is further increased.

    On the other hand, in order to suppress such an increase in pressure loss, it is conceivable to adopt a configuration in which the flat tubes are lengthened in the width direction (the direction in which air passes) to increase the number of refrigerant flow paths. However, when the width of the flat tube is increased in this way, it becomes difficult to bend the flat tube in the width direction, and the heat of another surface (for example, four surfaces) having a plurality of side portions through which air passes is provided. It becomes difficult to manufacture the exchanger.

    The present invention has been made in view of such a point, and an object of the present invention is to provide a heat exchanger in which a plurality of refrigerant flow paths are formed inside a flat tube, the pressure loss when the refrigerant flows through each refrigerant flow path. It is an object of the present invention to suppress the increase in the width of the flat tube and facilitate the bending in the width direction of the flat tube.

According to a first aspect of the present invention, there are provided a plurality of flat tubes (31, 41) each of which is arranged in parallel with each other and has a plurality of refrigerant flow paths (C), and fins joined to the flat tubes (31, 41). (32, 42), and a heat exchanger for exchanging heat between the refrigerant flowing through the refrigerant flow path (C) and air, wherein a plurality of row portions (31, 41) having a plurality of the flat tubes (31, 41) are provided. 30, 40) are arranged in the air passage direction, and the plurality of row portions (30, 40) are configured such that the refrigerant flows in parallel with each other in the plurality of row portions (30 , 40) . The flat tubes (31, 41) of the row portions (30, 40) are connected to the flat tubes (31, 41) such that the flat tubes (31, 41) of the row portions (30, 40) adjacent to each other in the air passage direction are along each other. , 41), each of which has at least one bent portion (33a, 33b, 33c) bent in the width direction, and the fins (32, 42) have the flattened outer edges corresponding to the outside of the heat exchanger. Multiple tubes (31,41) are inserted An inner edge of the fin (32, 42) corresponding to the inside of the heat exchanger is continuous in the arrangement direction of the plurality of flat tubes (31, 41), It has a first side part (23a) and a second side part (23b) .

    In the first invention, a plurality of rows (30, 40) are provided in the air passage direction, and a plurality of flat tubes (31, 41) are arranged in parallel in each row (30, 40). When the refrigerant flows through the heat exchanger, the refrigerant flows in parallel through the flat tubes (31, 41) of the respective row portions (30, 40). For example, when the refrigerant flows by connecting the flat tubes (31, 41) of such row portions (30, 40) in series, the flow rate of the refrigerant flowing through each refrigerant channel (C) increases, The flow velocity of the refrigerant flowing through (C) increases. Further, the flow path length of each refrigerant flow path (C) also becomes longer. On the other hand, in the present invention, since the refrigerant flows through the flat tubes (31, 41) of the respective row portions (30, 40) in parallel, the flow rate of the refrigerant flowing through each refrigerant flow path (C) decreases, The flow velocity of the refrigerant flowing through the flow path (C) also decreases. Further, the flow path length of each refrigerant flow path (C) also becomes short. The pressure loss of the refrigerant flowing through the refrigerant channel (C) is proportional to the square of the flow velocity of the refrigerant and the length of the refrigerant channel (C). Therefore, with such a configuration, pressure loss can be reduced.

    In the heat exchanger, the flat tubes (31, 41) of the adjacent row portions (30, 40) are formed so as to be along each other, and one or more bent portions (33a, 33a, 33) of each flat tube (31, 41) are formed. 33b, 33c). For this reason, the bending process of the flat tubes (31, 41) becomes easier as compared with a configuration in which the single-row flat tubes (31, 41) are elongated in the width direction.

According to a second aspect, in the first aspect, the width of the first side surface (23a) is shorter than the width of the second side surface (23b).

According to a third invention, in the first or second invention, a first header collecting pipe (50) is provided at one end of the first side surface (23a).

In a fourth aspect based on any one of the first to third aspects, the first side portion (23a), the second side portion (23b), the third side portion (23c), and the fourth side portion are provided. (23d) is a four-plane type.

In a fifth aspect based on the fourth aspect, the width of each of the first side portion (23a) and the fourth side portion (23d) is the same as that of the second side portion (23b) and the third side portion (23c). Is shorter than each width.

In a sixth aspect based on the fourth or fifth aspect, a first header collecting pipe (50) is provided at one end of the first side surface (23a), and is provided at one end of the fourth side surface (23d). Is characterized in that a second header collecting pipe (60) is provided.

    In the present invention, since the refrigerant flows in parallel in the flat tubes (31, 41) of the respective row portions (30, 40), the refrigerant flowing through the refrigerant flow path (C) of the flat tubes (31, 41) is formed. Pressure loss can be greatly reduced. As a result, a desired heat exchange efficiency can be obtained while suppressing an increase in power due to an increase in pressure loss.

Further, since it is not necessary to lengthen the flat tubes (31, 41) in the width direction, it is easy to bend the flat tubes (31, 41) of the respective row portions (30, 40). Thereby, the flat tubes (31, 41) of each row portion (30, 40) can be bent to manufacture a two- to four-plane heat exchanger, and the heat exchanger can be made more compact. In addition, by reducing the width of each flat tube (31, 41), the ventilation resistance between the flat tubes (31, 41) in each row (30, 40) can be reduced, and the decrease in heat transmittance is suppressed. it can. Furthermore, since the width of the flat tubes (31, 41) is reduced, it is possible to prevent dew condensation water from staying above the flat tubes (31, 41). As a result, frost formation on the surfaces of the flat tubes (31, 41) can be prevented .

FIG. 1 is a refrigerant circuit diagram illustrating a schematic configuration of the air conditioner according to the first embodiment. FIG. 2 is a schematic perspective view of the outdoor heat exchanger. FIG. 3 is a schematic configuration diagram in which an upwind row portion of the outdoor heat exchanger is developed in a plane, and shows a flow of a refrigerant when functioning as a condenser. FIG. 4 is a schematic configuration diagram in which the leeward row portion of the outdoor heat exchanger is developed in a plane, and shows the flow of the refrigerant when functioning as a condenser. FIG. 5 is an enlarged longitudinal sectional view of the portion indicated by A in FIG. FIG. 6 is an enlarged longitudinal sectional view of a portion indicated by B in FIG. FIG. 7 is a sectional view taken along line VII-VII of FIG. FIG. 8 is a sectional view taken along line VIII-VIII in FIG. FIG. 9 is a sectional view taken along the line VHI-VIIII of FIG. FIG. 10 is a sectional view taken along line XX of FIG. FIG. 11 is a graph showing temperature changes of refrigerant and air in the outdoor heat exchanger functioning as a condenser. FIG. 12 is a schematic configuration diagram in which the upwind row portion of the outdoor heat exchanger is developed in a plane, and shows the flow of the refrigerant when functioning as an evaporator.

FIG. 13 is a schematic configuration diagram in which the leeward row portion of the outdoor heat exchanger is developed in a plane, and illustrates the flow of the refrigerant when functioning as an evaporator. FIG. 14 is a graph showing temperature changes of refrigerant and air in the outdoor heat exchanger functioning as an evaporator. FIG. 15 is a diagram corresponding to FIG. 2 of the outdoor heat exchanger according to the second embodiment. FIG. 16 is a diagram corresponding to FIG. 3 of the outdoor heat exchanger according to the second embodiment. FIG. 17 is a diagram corresponding to FIG. 4 of the outdoor heat exchanger according to the second embodiment. FIG. 18 is a diagram corresponding to FIG. 12 of the outdoor heat exchanger according to the second embodiment. FIG. 19 is a diagram corresponding to FIG. 13 of the outdoor heat exchanger according to the second embodiment. FIG. 20 is a schematic top view of the outdoor heat exchanger functioning as a condenser. FIG. 21 is a diagram corresponding to FIG. 7 of the outdoor heat exchanger according to another embodiment.

    An embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

<< Embodiment 1 >>
The heat exchanger of the present embodiment is an outdoor heat exchanger (23) provided in the air conditioner (10). Hereinafter, the air conditioner (10) will be described first, and then the outdoor heat exchanger (23) will be described in detail.

<Overall configuration of air conditioner>
The air conditioner (10) will be described with reference to FIG.

    The air conditioner (10) includes an outdoor unit (11) and an indoor unit (12). The outdoor unit (11) and the indoor unit (12) are connected to each other via a liquid-side communication pipe (13) and a gas-side communication pipe (14). In the air conditioner (10), the outdoor unit (11), the indoor unit (12), the liquid side communication pipe (13), and the gas side communication pipe (14) are connected to form a refrigerant circuit (20). ing.

    The refrigerant circuit (20) is provided with a compressor (21), a four-way switching valve (22), an outdoor heat exchanger (23), an expansion valve (24), and an indoor heat exchanger (25). ing. The compressor (21), the four-way switching valve (22), the outdoor heat exchanger (23), and the expansion valve (24) are housed in the outdoor unit (11). The outdoor unit (11) is provided with an outdoor fan (15) for supplying outdoor air to the outdoor heat exchanger (23). The indoor heat exchanger (25) is housed in the indoor unit (12). The indoor unit (12) is provided with an indoor fan (16) for supplying indoor air to the indoor heat exchanger (25).

    The refrigerant circuit (20) is a closed circuit filled with the refrigerant. In the refrigerant circuit (20), the compressor (21) has its discharge pipe connected to the first port of the four-way switching valve (22) and its suction pipe connected to the second port of the four-way switching valve (22). Have been. In the refrigerant circuit (20), the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger (25) are sequentially arranged from the third port to the fourth port of the four-way switching valve (22). ) And are arranged. In this refrigerant circuit (20), the outdoor heat exchanger (23) is connected to the expansion valve (24) via a pipe (17), and the third of the four-way switching valve (22) is connected via a pipe (18). Connected to port.

    The compressor (21) is a scroll type or rotary type hermetic compressor. The four-way switching valve (22) includes a first state (a state shown by a solid line in FIG. 1) in which the first port communicates with the third port and a second port communicates with the fourth port, and a first state. The state is switched to a second state (a state shown by a broken line in FIG. 1) in which the port communicates with the fourth port and the second port communicates with the third port. The expansion valve (24) is a so-called electronic expansion valve.

  The outdoor heat exchanger (23) causes outdoor air to exchange heat with the refrigerant. The outdoor heat exchanger (23) will be described later. On the other hand, the indoor heat exchanger (25) causes indoor air to exchange heat with the refrigerant. The indoor heat exchanger (25) is configured by a so-called cross-fin type fin-and-tube heat exchanger including a heat transfer tube that is a circular tube.

−Operation of air conditioner−
The air conditioner (10) selectively performs a cooling operation and a heating operation.

    In the refrigerant circuit (20) during the cooling operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the first state. In this state, the refrigerant circulates in the order of the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger (25), and the outdoor heat exchanger (23) functions as a condenser, and the indoor heat exchanger (25) functions as an evaporator. In the outdoor heat exchanger (23), the gas refrigerant flowing from the compressor (21) radiates heat to outdoor air and condenses, and the condensed refrigerant flows out toward the expansion valve (24).

    In the refrigerant circuit (20) during the heating operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the second state. In this state, refrigerant circulates in the order of the indoor heat exchanger (25), the expansion valve (24), and the outdoor heat exchanger (23), and the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. The refrigerant that has been expanded into the gas-liquid two-phase state when passing through the expansion valve (24) flows into the outdoor heat exchanger (23). The refrigerant that has flowed into the outdoor heat exchanger (23) absorbs heat from outdoor air and evaporates, and then flows out toward the compressor (21).

<Overall configuration of outdoor heat exchanger>
The outdoor heat exchanger (23) according to the first embodiment will be described with reference to FIGS. Note that the number of flat tubes (31, 41) shown in the following description is merely an example.

    As shown in FIG. 2, the outdoor heat exchanger (23) is a four-sided air heat exchanger having four side portions (23a, 23b, 23c, 23d). Specifically, in the outdoor heat exchanger (23), the first side surface (23a), the second side surface (23b), the third side surface (23c), and the fourth side surface (23d) are continuously formed. Is done. The first side portion (23a) is located on the lower left side in FIG. 2, the second side portion (23b) is located on the upper left side in FIG. 2, and the third side portion (23c) is located on the upper right side in FIG. The fourth side surface portion (23d) is located on the lower right side in FIG. The heights of the side portions (23a, 23b, 23c, 23d) are substantially equal. Each width of the first side portion (23a) and the fourth side portion (23d) is shorter than the width of the second side portion (23b) and the third side portion (23c).

    In the outdoor heat exchanger (23), when the outdoor fan (15) is operated, the outdoor air outside each of the side portions (23a, 23b, 23c, and 23d) is moved to the respective side portions (23a, 23b, 23c, and 23c). 23d) flows inside (see the arrow in FIG. 2). This air is discharged from an air outlet formed in an upper portion of an outdoor casing (not shown).

    As shown in FIGS. 2 to 4, the outdoor heat exchanger (23) has a two-row structure having two row portions (30, 40) having flat tubes (31, 41) and fins (32, 42). Heat exchanger. The outdoor heat exchanger (23) may have three or more rows. In the outdoor heat exchanger (23) of the present embodiment, the leeward row portion (30) constitutes the leeward row portion (30) in the air passage direction, and the leeward row portion (40) constitutes the leeward row portion. ing. 3 and 4, the leeward row portion (30) and the leeward row portion (40) are each schematically shown by being developed in a plane.

    The outdoor heat exchanger (23) includes a first header collecting pipe (50), a second header collecting pipe (60), a third header collecting pipe (70), a fourth header collecting pipe (80), a first branch unit ( 91), and a second branch unit (92). The first header collecting pipe (50) stands upright near one end of the windward row section (30) on the first side face (23a) side. The second header collecting pipe (60) is provided upright in the vicinity of the other end on the fourth side face (23d) side of the windward row (30). The third header collecting pipe (70) stands upright near one end of the leeward row section (40) on the first side face (23a) side. The fourth header collecting pipe (80) is erected near the other end of the leeward row part (40) on the fourth side face part (23d) side. The first branch unit (91) is erected near the first header collecting pipe (50). The second branch unit (92) stands upright near the third header collecting pipe (70).

    Flat tubes (31, 41), fins (32, 42), first header manifold (50), second header manifold (60), third header manifold (70), fourth header manifold (80) , The first branch unit (91) and the second branch unit (92) are members made of an aluminum alloy, and are joined to each other by brazing.

(Windward row)
As shown in FIGS. 2, 3, and 5 to 10, the windward row portion (30) includes a number of flat tubes (31) and a number of fins (32).

    The flat tube (31) is a heat transfer tube whose cross section perpendicular to the axis has a flat, substantially elliptical shape (see FIG. 7). The plurality of flat tubes (31) are arranged such that upper and lower flat portions face each other. That is, the plurality of flat tubes (31) are arranged one above the other with a certain interval between them, and the respective cylinder axes are substantially parallel.

    As shown in FIG. 2, the flat tube (31) includes a first windward tube portion (31a) along the first side surface portion (23a) and a second windward tube portion along the second side surface portion (23b). (31b), a third upwind pipe section (31c) along the third side section (23c), and a fourth upwind pipe section (31d) along the fourth side section (23d). ing. As shown in FIG. 2, the flat tube (31) has a first windward bend in which the first windward pipe portion (31a) is bent inward at a substantially right angle horizontally and inward with respect to the second windward pipe portion (31b). Part (33a), a second windward bent part (33b) for bending the third windward pipe part (31c) horizontally inward at a substantially right angle with respect to the second windward pipe part (31b), and a third wind A third windward bent portion (33c) is provided to bend the fourth windward pipe portion (31d) inward at a substantially right angle horizontally inward with respect to the upper pipe portion (31c).

    In each flat tube (31), the end of the first windward pipe portion (31a) is inserted into the first header collecting pipe (50) (see FIG. 5), and the end of the fourth windward pipe portion (31d). The part is inserted into the second header collecting pipe (60) (see FIG. 6).

    As shown in FIG. 7, a plurality of refrigerant channels (C) are formed in each flat tube (31). The plurality of refrigerant passages (C) are passages extending in the cylinder axis direction of the flat tube (31), and are arranged in a line in the width direction (the air passage direction) of the flat tube (31). Each refrigerant channel (C) is open at both end surfaces of the flat tube (31). The refrigerant supplied to the windward row part (30) exchanges heat with air while flowing through the refrigerant flow path (C) of the flat tube (31). The plurality of refrigerant flow paths (C) of each flat tube (31) of the windward row part (30) constitute a windward refrigerant flow path group (C1).

    As shown in FIG. 7, the fin (32) is a vertically long plate-like fin formed by pressing a metal plate. The plurality of fins (32) are arranged at regular intervals in the axial direction of the flat tube (31). The fin (32) is formed with a large number of elongated notches (32a) extending from the outer edge of the fin (32) (ie, the edge on the windward side) in the width direction of the fin (32). In the fin (32), a number of notches (32a) are formed at regular intervals in the longitudinal direction (up-down direction) of the fin (32). The windward portion of the notch (32a) forms a tube insertion portion (32b). The flat tube (31) is inserted into the tube insertion portion (32b), and is joined to the periphery of the tube insertion portion (32b) by brazing. Further, a louver (32c) for promoting heat transfer is formed in the fin (32).

    As shown in FIG. 3, two heat exchange regions (35, 37) are formed vertically on the windward row (30). The upper heat exchange area constitutes the windward main heat exchange area (35), and the lower heat exchange area constitutes the windward auxiliary heat exchange area (37). The number of flat tubes (31) corresponding to the windward auxiliary heat exchange region (37) is smaller than the number of flat tubes (31) forming the windward main heat exchange region (35).

    The upwind main heat exchange area (35) is divided into six upwind main heat exchange sections (36) arranged vertically. The upwind auxiliary heat exchange area (37) is divided into six upwind auxiliary heat exchange sections (38) arranged vertically. That is, the windward main heat exchange area (35) and the windward auxiliary heat exchange area (37) are each divided into the same number of heat exchange sections. The number of the windward main heat exchange section (36) and the windward auxiliary heat exchange section (38) is merely an example, and is preferably plural.

    As shown in FIGS. 3 and 6, each windward main heat exchange section (36) is provided with the same number (for example, 6) of flat tubes (31). The number of flat tubes (31) provided in each windward main heat exchange section (36) is merely an example, and may be plural or one.

    As shown in FIGS. 3 and 5, each windward auxiliary heat exchange unit (38) is provided with the same number (for example, two) of flat tubes (31). The number of flat tubes (31) provided in each windward auxiliary heat exchange section (38) is merely an example, and may be plural or one.

(Leeward row)
As shown in FIGS. 2, 4, 5 to 10, the leeward row portion (40) includes a number of flat tubes (41) and a number of fins (42).

    The flat tube (41) is a heat transfer tube whose cross section perpendicular to the axis has a flat, substantially elliptical shape (see FIG. 7). The plurality of flat tubes (41) are arranged with upper and lower flat portions facing each other. That is, the plurality of flat tubes (41) are arranged one above the other at regular intervals, and their cylinder axes are substantially parallel.

    As shown in FIG. 2, the flat tube (41) has a first leeward pipe portion (41a) along the inner edge of the first leeward pipe portion (31a) and an inner edge of the second leeward pipe portion (31b). Along the second leeward pipe section (41b), the third leeward pipe section (41c) along the inner edge of the third leeward pipe section (31c), and along the inner edge of the fourth leeward pipe section (31d). And a fourth leeward pipe section (41d). The flat tube (41) includes a first leeward bent portion (43a) for bending the first leeward tube portion (41a) horizontally and inward at a substantially right angle with respect to the second leeward tube portion (41b), and a second leeward tube. A second leeward bent portion (43b) for bending the third leeward tube portion (41c) horizontally inward at a substantially right angle with respect to the portion (41b); and a fourth leeward tube portion for the third leeward tube portion (41c). A third leeward bent portion (43c) for bending (41d) horizontally inward at a substantially right angle is provided.

    In each flat tube (41), the end of the first leeward pipe (41a) is inserted into the third header collecting pipe (70), and the end of the fourth leeward pipe (41d) is connected to the fourth header collecting pipe (41). 80) (see FIG. 4).

    As shown in FIGS. 7 to 10, a plurality of refrigerant channels (C) are formed in each flat tube (41). The plurality of refrigerant channels (C) are passages extending in the cylinder axis direction of the flat tube (41), and are arranged in a line in the width direction of the flat tube (41) (the direction in which air passes). Each refrigerant channel (C) is open at both end surfaces of the flat tube (41). The refrigerant supplied to the leeward row (40) exchanges heat with air while flowing through the refrigerant flow path (C) of the flat tube (41). The plurality of refrigerant channels (C) of each flat tube (41) of the leeward row (40) constitute a leeward refrigerant channel group (C2).

    As shown in FIG. 7, the fin (42) is a vertically long plate-like fin formed by pressing a metal plate. The plurality of fins (42) are arranged at regular intervals in the axial direction of the flat tube (41). The fin (42) has a large number of elongated notches (42a) extending in the width direction of the fin (42) from the outer edge of the fin (42) (that is, the edge on the windward side). In the fin (42), a large number of notches (42a) are formed at regular intervals in the longitudinal direction (up-down direction) of the fin (42). The windward portion of the notch (42a) forms a tube insertion portion (42b). The flat tube (41) is inserted into the tube insertion portion (42b), and is joined to the periphery of the tube insertion portion (42b) by brazing. The fin (42) is formed with a louver (42c) for promoting heat transfer.

    As shown in FIG. 4, two heat exchange regions (45, 47) are formed vertically on the leeward row (40). The upper heat exchange region constitutes a leeward main heat exchange region (45), and the lower heat exchange region constitutes a leeward auxiliary heat exchange region (47). The number of flat tubes (41) corresponding to the leeward auxiliary heat exchange region (47) is smaller than the number of flat tubes (41) constituting the leeward main heat exchange region (45).

    The leeward main heat exchange area (45) is divided into six leeward main heat exchange sections (46) arranged vertically. The leeward auxiliary heat exchange area (47) is divided into six leeward auxiliary heat exchange units (48) arranged vertically. That is, the leeward main heat exchange area (45) and the leeward auxiliary heat exchange area (47) are each divided into the same number of heat exchange sections. The number of the leeward main heat exchange units (46) and the number of the leeward auxiliary heat exchange units (48) are merely examples, and are preferably plural.

    As shown in FIG. 4, each leeward main heat exchange part (46) is provided with the same number (for example, six) of flat tubes (41). The number of flat tubes (41) provided in each leeward main heat exchange section (46) is merely an example, and may be plural or one.

    As shown in FIGS. 5 and 6, each leeward auxiliary heat exchange section (48) is provided with the same number (for example, two) of flat tubes (41). The number of flat tubes (41) provided in each leeward auxiliary heat exchange section (48) is merely an example, and may be plural or one.

[Third header collecting pipe]
As shown in FIGS. 2 and 4, the third header collecting pipe (70) is a cylindrical member whose upper and lower ends are closed. The length (height) of the third header collecting pipe (70) substantially matches the height of the leeward row portion (30) and the leeward row portion (40).

    The internal structure of the third header collecting pipe (70) is the same as that of the first header collecting pipe (50) shown in FIG. That is, as shown in FIG. 4, the internal space of the third header collecting pipe (70) is vertically divided by the main partition (71). The space above the main partition (71) is a leeward upper space (72) corresponding to the leeward main heat exchange area (45). The space below the main partition (81) is a leeward space (73) corresponding to the leeward auxiliary heat exchange area (47). One end of one second main gas pipe (72a) is connected to a vertically intermediate portion of the leeward upper space (72). The other end of the second main gas pipe (72a) communicates with the gas side communication pipe (14).

    The leeward space (73) is divided into six leeward auxiliary spaces (75) by five partition plates (74) arranged vertically at equal intervals. These six downwind auxiliary spaces (75) respectively correspond to the six downwind auxiliary heat exchange sections (48). For example, a first leeward pipe portion (41a) of two flat tubes (41) communicates with each leeward auxiliary space (75).

[Fourth header collecting pipe]
As shown in FIG. 2, FIG. 4, and FIG. 8 to FIG. 10, the fourth header collecting pipe (80) is a cylindrical member whose upper and lower ends are closed. The length (height) of the fourth header collecting pipe (80) is substantially the same as the height of the leeward row portion (30) and the leeward row portion (40).

    The internal structure of the fourth header collecting pipe (80) is the same as that of the second header collecting pipe (60) shown in FIG. That is, as shown in FIG. 4, the internal space of the fourth header collecting pipe (80) is vertically divided by the main partition (81). The space above the main partition (81) is a leeward upper space (82) corresponding to the leeward main heat exchange area (45). The space below the main partition (81) is a leeward space (83) corresponding to the leeward auxiliary heat exchange area (47).

    The leeward upper space (82) is partitioned into six leeward main communication spaces (85) by five partition plates (84) arranged at equal intervals up and down. Each of the six leeward main communication spaces (85) corresponds to one of the six leeward main heat exchange sections (46). The leeward main communication space (85) is in communication with, for example, first leeward pipe portions (41a) of six flat tubes (41).

    The leeward space (83) is divided into six leeward auxiliary communication spaces (87) by five partition plates (86) arranged at equal intervals in the vertical direction. These six downwind auxiliary communication spaces (87) respectively correspond to the six downwind auxiliary heat exchange sections (48). For example, each fourth leeward pipe section (41d) of two flat pipes (41) communicates with each leeward auxiliary communication space (87).

    Six leeward communication pipes (88) are connected to the fourth header collecting pipe (80). The leeward communication pipe (88) is the end of the flat pipe (41) in the leeward main heat exchange area (45) of the leeward row section (40) and the end of the flat pipe (41) in the leeward auxiliary heat exchange area (47). And are connected.

    Specifically, the first leeward communication pipe (88) connects the uppermost leeward auxiliary communication space (87) and the lowermost leeward main communication space (85), and the second leeward communication pipe (88). ) Connects the second leeward auxiliary communication space (87) from the top and the second leeward main communication space (85) from the bottom, and the third leeward communication pipe (88) is three-stage from the top The leeward auxiliary communication space (87) is connected to the third leeward main communication space (85) from the bottom. The fourth leeward communication pipe (88) connects the fourth leeward auxiliary communication space (87) with the fourth leeward main communication space (85) from the top, and a fifth leeward communication pipe (88). 88) connects the fifth leeward auxiliary communication space (87) from the top and the fifth leeward main communication space (85) from the bottom, and the sixth leeward communication pipe (88) The leeward auxiliary communication space (87) is connected to the uppermost leeward main communication space (85).

[First branch unit]
As shown in FIGS. 2 and 3, the first branch unit (91) is attached to the first header collecting pipe (50). The first branch unit (91) has a cylindrical portion (91a), six liquid-side connection pipes (91b), and one first main liquid pipe (91c).

    The cylindrical portion (91a) is formed in a cylindrical shape lower than the first header collecting pipe (50), and stands upright along a lower portion of the first header collecting pipe (50). The six liquid-side connection pipes (91b) are arranged vertically and connected to the cylindrical portion (91a). The number of each liquid side connection pipe (91b) is the same as the number of the windward auxiliary communication spaces (67) (six in this example). Each liquid-side connection pipe (91b) is in communication with each of the windward auxiliary communication spaces (67). One end of the first main liquid pipe (91c) is connected to a lower part of the cylindrical portion (91a). The first main liquid pipe (91c) and each liquid-side connection pipe (91b) communicate with each other via the internal space of the cylindrical portion (91a).

[Second branch unit]
As shown in FIGS. 2 and 4, the second branch unit (92) is attached to the third header collecting pipe (70). The second branch unit (92) has a cylindrical portion (92a), six liquid-side connection pipes (92b), and one second main liquid pipe (92c).

    The cylindrical portion (92a) is formed in a cylindrical shape lower than the third header collecting pipe (70), and stands up along a lower portion of the third header collecting pipe (70). The six liquid-side connection pipes (92b) are arranged vertically and connected to the cylindrical portion (92a). The number of each liquid side connection pipe (92b) is the same as the number of the leeward auxiliary spaces (75) (six in this example). Each liquid-side connection pipe (92b) is in communication with each leeward auxiliary space (75). One end of the second main liquid pipe (92c) is connected to a lower part of the cylindrical portion (92a). The second main liquid pipe (92c) and each liquid side connection pipe (92b) communicate with each other via the internal space of the cylindrical portion (92a).

(Liquid branch pipe)
As schematically shown in FIG. 2, the first main liquid pipe (91c) of the first branch unit (91) and the second main liquid pipe (92c) of the second branch unit (92) include a liquid branch pipe. (28) is connected. The liquid branch pipe (28) bifurcates and communicates with each of the flow dividing units (91, 92) and each of the auxiliary spaces (55, 75). That is, the liquid branch pipe (28) is connected to the other end (the first windward pipe part (31a)) of each flat pipe (31) of the leeward row part (30) and the flattened pipe part (31a) of the leeward row part (40). The other end of the pipe (41) (the first leeward pipe section (41a)) is branched and communicated.

(Gas branch pipe)
As schematically shown in FIG. 2, a gas branch pipe (52a) in the leeward row (30) and a second main gas pipe (72a) in the leeward row (40) have a gas branch pipe (72). 29) is connected. The gas branch pipe (29) bifurcates and communicates with the upwind space (52) and the downwind space (72). That is, the gas branch pipe (29) includes the other end (the first leeward pipe section (31a)) of the leeward row section (30) and the other end (the first leeward pipe section) of the leeward row section (40). (41a)).

-Refrigerant flow in outdoor heat exchanger-
When functioning as a condenser and an evaporator, the outdoor heat exchanger (23) is provided with a refrigerant flowing through each flat tube (31) of the leeward row (30) and a flat tube (41) of the leeward row (40). ) Is configured to be parallel to the refrigerant flowing therethrough. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( 40) the refrigerant flows in parallel with the flat tubes (41) in the leeward main heat exchange area (45), and the flat tubes (31) in the leeward auxiliary heat exchange area (47) in the leeward row (30); The refrigerant is configured to flow in parallel with the flat tube (41) of the leeward auxiliary heat exchange area (47) of the leeward row (40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) And the refrigerant flowing through the leeward refrigerant flow path group (C2) are configured to flow in parallel with each other.

    Further, when the outdoor heat exchanger (23) functions as a condenser and an evaporator, the outdoor heat exchanger (23) has a refrigerant flowing through each flat tube (31) of the leeward row (30) and a flat tube (40) of the leeward row (40). 41) and the refrigerant flowing in the same direction. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( Refrigerant flows in the same direction with the flat tube (41) in the leeward auxiliary heat exchange area (47) in 40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) Flows through the leeward refrigerant flow path group (C2) in the same direction.

[Refrigerant flow in the case of a condenser]
During the cooling operation of the air conditioner (10), the indoor heat exchanger (25) functions as an evaporator, and the outdoor heat exchanger (23) functions as a condenser. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the cooling operation will be described.

    In the outdoor heat exchanger (23), the gas refrigerant discharged from the compressor (21) flows into the gas branch pipe (29), and the first main gas pipe (52a) and the second main gas pipe (72a). And divert to

    As shown in FIG. 3, the refrigerant supplied to the first main gas pipe (52a) flows into the windward upstream space (52) of the first header collecting pipe (50), and flows into each windward main heat exchange section (52). 36). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind main heat exchange section (36) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each of the windward main communication spaces (65) of the second header collecting pipe (60), and flows into each of the windward communication pipes (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and is distributed to each windward auxiliary heat exchange unit (38). You. Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) further radiates heat to air and condenses, and the supercooled state (ie, (Liquid single phase state).

    The supercooled liquid refrigerant is supplied to each windward auxiliary space (55) of the first header collecting pipe (50) and merges in the first branch unit (91) to form the first main liquid pipe (91c). Flows through.

    As shown in FIG. 4, the refrigerant supplied to the second main gas pipe (72a) flows into the leeward upper space (72) of the third header collecting pipe (70), and flows into the leeward main heat exchange section (46). Be distributed. Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and is distributed to each leeward auxiliary heat exchange unit (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) further radiates heat to the air to be condensed, and becomes a supercooled state (that is, Phase state).

    The liquid refrigerant in the supercooled state is supplied to each leeward auxiliary space (75) of the third header collecting pipe (70), merges in the second branch unit (92), and flows through the second main liquid pipe (92c). Flows.

    The refrigerant flowing through the first main liquid pipe (91c) and the refrigerant flowing through the second main liquid pipe (92c) merge at the liquid branch pipe (28) and are sent to the liquid side communication pipe (13).

(Temperature change of refrigerant and air in case of condenser)
FIG. 11 shows an example of temperature changes of air and refrigerant in the outdoor heat exchanger (23) functioning as a condenser.

    The gas refrigerant in a superheated state at 70 ° C. flows into the flat tube (31) of the windward main heat exchange area (35). This refrigerant becomes a 50 ° C. saturated gas refrigerant in the middle of the upstream refrigerant flow path group (C1) of the flat tubes (31) in the upstream main heat exchange area (35), and then gradually condenses. The refrigerant flowing out of the windward main heat exchange area (35) flows into the flat tube (31) of the windward auxiliary heat exchange area (37). This refrigerant becomes a liquid-phase single-phase saturated refrigerant (saturation temperature: 50 ° C.) in the upwind refrigerant flow path group (C1) of the flat tube (31) in the windward auxiliary heat exchange area (37), and then further radiates heat. To a supercooled state (for example, 42 ° C.).

    The gas refrigerant in a superheated state at 70 ° C. flows into the flat tube (41) in the leeward main heat exchange area (45). This refrigerant becomes a 50 ° C. saturated gas refrigerant in the leeward refrigerant flow path group (C2) of the flat tube (41) in the leeward main heat exchange area (45), and then gradually condenses. The refrigerant flowing out of the leeward main heat exchange area (45) flows into the flat tube (41) of the leeward auxiliary heat exchange area (47). This refrigerant becomes a liquid-phase single-phase saturated refrigerant (saturation temperature: 50 ° C.) in the leeward refrigerant flow path group (C2) of the flat tubes (41) in the leeward auxiliary heat exchange area (47), and then further radiates heat and becomes excessive. It will be in a cooling state (for example, 47 ° C.).

    On the other hand, for example, air at 35 ° C. flows into the leeward main heat exchange area (35) and the leeward auxiliary heat exchange area (37). The 45 ° C air heated in the leeward main heat exchange area (35) flows into the leeward main heat exchange area (45), and the leeward auxiliary heat exchange area (37) flows into the leeward auxiliary heat exchange area (37). When passing through (35), heated 40 ° C. air flows in.

    As described above, when the outdoor heat exchanger (23) functions as a condenser, the temperature of the refrigerant in the entire outdoor heat exchanger (23) becomes higher than the temperature of the air, and the amount of heat released from the refrigerant to the air (ie, , The heat radiation of the refrigerant).

[Flow of refrigerant in evaporator]
During the heating operation of the air conditioner (10), the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the heating operation will be described.

    To the outdoor heat exchanger (23), a refrigerant that has been expanded into a gas-liquid two-phase state when passing through the expansion valve (24) is supplied through a pipe (17). The refrigerant flows into the liquid branch pipe (28), and is divided into a first main liquid pipe (91c) and a second main liquid pipe (92c).

    As shown in FIG. 12, the refrigerant supplied to the first branch unit (91) is branched to the respective liquid-side connection pipes (91b), and each of the windward auxiliary spaces (55) of the first header collecting pipe (50). The heat is further distributed to each windward auxiliary heat exchange section (38). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) absorbs heat from air and evaporates. Then, each refrigerant is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and flows into each windward communication pipe (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward main communication space (65) of the second header collecting pipe (60), and is distributed to each windward main heat exchange unit (36). You. Each refrigerant passing through each windward refrigerant flow path group (C1) of each flat tube (31) of each windward main heat exchange section (36) further absorbs heat from the air and evaporates, and the superheated state (that is, gas) (Single-phase state).

    The superheated gas refrigerant joins in the space on the windward side (52) of the first header collecting pipe (50), and is sent from the first main gas pipe (52a) to the gas-side communication pipe (14).

    As shown in FIG. 13, the refrigerant supplied to the second branch unit (92) is diverted to each liquid-side connection pipe (92b), and from each leeward auxiliary space (75) of the third header collecting pipe (70). It is distributed to each downwind auxiliary heat exchange section (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) absorbs heat from air and evaporates. Thereafter, each refrigerant is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and is distributed to each leeward main heat exchange section (46). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) further absorbs heat from air and evaporates, and is overheated (ie, gas single phase). State).

    The superheated gas refrigerant joins in the leeward space (72) of the third header collecting pipe (70) and flows through the second main gas pipe (72a).

    The refrigerant flowing through the first main gas pipe (52a) and the refrigerant flowing through the second main gas pipe (72a) merge at the gas branch pipe (29) and are sent to the gas side communication pipe (14).

(Temperature change of refrigerant and air in case of evaporator)
An example of the temperature change of the air and the refrigerant in the outdoor heat exchanger (23) functioning as an evaporator will be described with reference to FIG.

    A refrigerant in a gas-liquid two-phase state having a saturation temperature of 1.5 ° C. flows into the flat tube (31) of the windward auxiliary heat exchange area (37). In the flat tube (31) of the windward auxiliary heat exchange area (37), the saturation temperature of the refrigerant becomes about 0.5 ° C due to the pressure loss when the refrigerant passes through the windward refrigerant flow path group (C1). It gradually decreases until.

    The gas-liquid two-phase refrigerant flowing out of the windward auxiliary heat exchange area (37) flows into the flat tube (41) of the windward main heat exchange area (35). In the flat tube (31) of the windward main heat exchange area (35), the saturation temperature of the refrigerant further decreases due to pressure loss when the refrigerant passes through the windward refrigerant flow path group (C1) (for example, 0 ° C). The refrigerant enters a gas single-phase state in the middle of the flat tube (31) in the windward main heat exchange region (35), and after its temperature rises to 1 ° C, the flat tube in the windward main heat exchange region (35). Outflow from (31).

    A refrigerant in a gas-liquid two-phase state having a saturation temperature of 1.5 ° C. flows into the flat tube (41) of the leeward auxiliary heat exchange area (47). In the flat tube (41) of the leeward auxiliary heat exchange area (47), due to the pressure loss when the refrigerant passes through the leeward refrigerant flow path group (C2), the saturation temperature of the refrigerant gradually increases to about 0.5 ° C. descend.

    A refrigerant in a gas-liquid two-phase state having a saturation temperature of 1.5 ° C. flows into the flat tube (41) of the leeward auxiliary heat exchange area (47). In the flat tube (41) of the leeward auxiliary heat exchange area (47), due to the pressure loss when the refrigerant passes through the leeward refrigerant flow path group (C2), the saturation temperature of the refrigerant gradually increases to about 0.5 ° C. descend.

    The gas-liquid two-phase refrigerant flowing out of the leeward auxiliary heat exchange area (47) flows into the flat tube (41) in the leeward main heat exchange area (45). In the flat tube (41) of the leeward main heat exchange area (45), the saturation temperature of the refrigerant further decreases due to the pressure loss when the refrigerant passes through the leeward refrigerant flow path group (C2) (for example, about 0). ° C). This refrigerant enters a gas single-phase state in the middle of the flat tube (41) in the leeward main heat exchange region (45), and after its temperature rises to 1 ° C., the flat tube (41) in the leeward main heat exchange region (45). ).

    On the other hand, air at, for example, 7 ° C. flows into the windward auxiliary heat exchange area (37) and the windward main heat exchange area (35). Further, the air cooled at 3 ° C., which is cooled when passing through the leeward auxiliary heat exchange area (37), flows into the leeward auxiliary heat exchange area (47). Cooled 2 ° C. air flows in as it passes through the upper main heat exchange zone (35).

    As described above, when the outdoor heat exchanger (23) functions as an evaporator, the temperature of the refrigerant in the entire outdoor heat exchanger (23) becomes lower than the temperature of the air, and the amount of heat ( That is, the amount of heat absorbed by the refrigerant) is secured.

[Pressure loss reduction effect]
As described above, in the present embodiment, in both the case where the outdoor heat exchanger (23) functions as a condenser and the case where the outdoor heat exchanger functions as an evaporator, the refrigerant is connected to the leeward refrigerant flow path group (C1) and the leeward. It flows in parallel with the refrigerant flow path group (C2).

For example, in a configuration (comparative example) in which the refrigerant flows in series through the two refrigerant flow path groups (C1, C2), the flow velocity of the refrigerant flowing through each flat tube (31, 41) is twice that of the present embodiment, and the refrigerant flow The total length of the road (C) is also doubled. The pressure loss in the refrigerant channel (C) is proportional to the square of the flow velocity, and is proportional to the total length of the refrigerant channel. Therefore, the pressure loss of the refrigerant channel (C) of the comparative example is approximately eight times (= 2 × 2 ² ) that of the present embodiment. That is, in the present embodiment, the refrigerant is caused to flow in parallel through the refrigerant flow path group (C1) of the leeward row (30) and the refrigerant flow path group (C2) of the leeward row (40). The pressure loss in the refrigerant channel (C) can be reduced to 1/8 as compared with the example.

    When the pressure loss of the refrigerant can be reduced in this way, it is possible to prevent a decrease in the pressure of the refrigerant in, for example, the outdoor heat exchanger (23) of the evaporator. That is, in the outdoor heat exchanger (23) of the evaporator, since the amount of decrease in the pressure of the refrigerant due to the pressure loss can be reduced, the pressure difference between the inlet and the outlet of the outdoor heat exchanger (23) (that is, the compressor ( The difference between the suction pressure of 21) and the pressure of the refrigerant flowing into the outdoor heat exchanger (23)) can be reduced. As a result, when the suction pressure of the compressor (21) is set to a predetermined value, the evaporation pressure of the refrigerant flowing into the outdoor heat exchanger (23) and, consequently, the evaporation temperature can be reduced as compared with the comparative example. Thereby, in the outdoor heat exchanger (23), the difference between the temperature of the refrigerant flowing through the refrigerant flow path group (C1) in the windward row (30) and the temperature of the air passing through the windward row (30) can be increased. In addition, the evaporation capacity of the outdoor heat exchanger (23) can be improved.

-Effects of Embodiment 1-
In the first embodiment, the following operations and effects can be obtained.

    Since the refrigerant flows in parallel in the flat tubes (31, 41) of each row (30, 40), the pressure loss of the refrigerant flowing through the refrigerant flow path (C) of each flat tube (31, 41) is greatly reduced. Can be reduced to As a result, a desired heat exchange efficiency can be obtained while suppressing an increase in power due to an increase in pressure loss.

    Since it is not necessary to lengthen the flat tubes (31, 41) in the width direction, the bending process of the flat tubes (31, 41) of each row portion (30, 40) becomes easy. Thereby, the flat tubes (31, 41) of each row portion (30, 40) can be bent to manufacture a four-sided heat exchanger, and the heat exchanger can be made compact.

    As shown in FIG. 2, a liquid branch pipe (28) and a gas branch pipe (29) for flowing the refrigerant in parallel to the respective row portions (30, 40) can be arranged collectively. Thereby, the space of the piping can be made compact, or the installation of the piping can be facilitated.

  In addition, by reducing the width of each flat tube (31, 41), the ventilation resistance between the flat tubes (31, 41) in each row (30, 40) can be reduced, and the decrease in heat transmittance is suppressed. it can. Furthermore, since the width of the flat tubes (31, 41) is reduced, it is possible to prevent dew condensation water from staying above the flat tubes (31, 41). As a result, frost formation on the surfaces of the flat tubes (31, 41) can be prevented.

<< Embodiment 2 >>
The air conditioner (10) of the second embodiment differs from the first embodiment in the configuration of the outdoor heat exchanger (23). In the outdoor heat exchanger (23) of the second embodiment, the configuration of the upwind row section (30) is the same as that of the first embodiment. Hereinafter, differences from the first embodiment will be described with reference to FIGS.

    In the second embodiment, the third header collecting pipe (70) is provided upright in the vicinity of one end of the leeward row (40) on the side of the fourth side surface (23d). The fourth header collecting pipe (80) is erected near the other end of the leeward row (40) on the first side face (23a) side. That is, in the second embodiment, the positions of the third header collecting pipe (70) and the fourth header collecting pipe (80) in the first embodiment are completely opposite in the longitudinal direction of the flat tubes (31, 41). ing. In the vicinity of the third header collecting pipe (70), as in the first embodiment, it stands upright near the second branch unit (92).

    The first main gas pipe (52a) and the second main gas pipe (72a) communicate with the gas side communication pipe (14) via a branch pipe (not shown). The first main liquid pipe (91c) and the second main liquid pipe (92c) communicate with the liquid side communication pipe (13) via a branch pipe (not shown).

-Refrigerant flow in outdoor heat exchanger-
As shown in FIGS. 16 to 19, when the outdoor heat exchanger (23) functions as a condenser and an evaporator, the outdoor heat exchanger (23) has a refrigerant flowing through each flat tube (31) of the windward row (30) and a leeward row. The refrigerant flowing through each flat tube (41) of the section (40) is configured to be parallel. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( 40) the refrigerant flows in parallel with the flat tubes (41) in the leeward main heat exchange area (45), and the flat tubes (31) in the leeward auxiliary heat exchange area (47) in the leeward row (30); The refrigerant is configured to flow in parallel with the flat tube (41) of the leeward auxiliary heat exchange area (47) of the leeward row (40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) And the refrigerant flowing through the leeward refrigerant flow path group (C2) are configured to flow in parallel with each other.

    Further, when the outdoor heat exchanger (23) functions as a condenser and an evaporator, the outdoor heat exchanger (23) has a refrigerant flowing through each flat tube (31) of the leeward row (30) and a flat tube (40) of the leeward row (40). 41) and the refrigerant flowing therethrough is configured to be in opposite directions to each other. Specifically, the outdoor heat exchanger (23) functioning as a condenser and an evaporator includes a flat tube (31) in the leeward main heat exchange area (35) of the leeward row (30) and a leeward row ( Refrigerant flows in opposite directions to the flat tube (41) of the leeward auxiliary heat exchange area (47) of 40). That is, the outdoor heat exchanger (23) functioning as a condenser and an evaporator is provided between the refrigerant flowing through the leeward refrigerant flow path group (C1) of the leeward main heat exchange area (35) and the leeward main heat exchange area (45). ) And the refrigerant flowing through the leeward refrigerant flow path group (C2) flow in opposite directions.

[In case of condenser]
During the cooling operation of the air conditioner (10), the indoor heat exchanger (25) functions as an evaporator, and the outdoor heat exchanger (23) functions as a condenser. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the cooling operation will be described.

    The gas refrigerant discharged from the compressor (21) is supplied to the outdoor heat exchanger (23) through the pipe (18). This refrigerant flows from the pipe (18) to the first main gas pipe (52a) and the second main gas pipe (82a).

    As shown in FIG. 16, the refrigerant supplied to the first main gas pipe (52a) flows into the upwind space (52) of the first header collecting pipe (50), and flows into each of the upwind main heat exchange sections (52). 36). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind main heat exchange section (36) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each of the windward main communication spaces (65) of the second header collecting pipe (60), and flows into each of the windward communication pipes (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and is distributed to each windward auxiliary heat exchange unit (38). You. Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) further radiates heat to air and condenses, and the supercooled state (ie, (Liquid single phase state).

    The supercooled liquid refrigerant is supplied to each windward auxiliary space (55) of the first header collecting pipe (50) and merges in the first branch unit (91) to form the first main liquid pipe (91c). It is sent to the liquid side connection pipe (13).

    As shown in FIG. 17, the refrigerant supplied from the pipe (18) to the second main gas pipe (72a) flows into the leeward upper space (72) of the third header collecting pipe (70), and the leeward main heat exchange is performed. Distributed to the department (46). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) releases heat to air and condenses. Thereafter, each refrigerant is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and is distributed to each leeward auxiliary heat exchange unit (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) further radiates heat to the air to be condensed, and becomes a supercooled state (that is, Phase state).

    The supercooled liquid refrigerant is supplied to each leeward auxiliary space (75) of the third header collecting pipe (70), merges in the second branch unit (92), and flows out of the first branch unit (91). The refrigerant is sent to the liquid-side communication pipe (13) together with the refrigerant.

[In case of evaporator]
During the heating operation of the air conditioner (10), the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. Here, the flow of the refrigerant in the outdoor heat exchanger (23) during the heating operation will be described.

    To the outdoor heat exchanger (23), a refrigerant that has been expanded into a gas-liquid two-phase state when passing through the expansion valve (24) is supplied through a pipe (17). This refrigerant is split from the pipe (17) into the first split unit (91) and the second split unit (92).

    As shown in FIG. 18, the refrigerant supplied to the first branch unit (91) is diverted to the respective liquid side connection pipes (91b), and each leeward auxiliary space (55) of the first header collecting pipe (50). The heat is further distributed to each windward auxiliary heat exchange section (38). Each refrigerant passing through each upwind refrigerant flow path group (C1) of each flat tube (31) of each upwind auxiliary heat exchange section (38) absorbs heat from air and evaporates. Then, each refrigerant is supplied to each windward auxiliary communication space (67) of the second header collecting pipe (60), and flows into each windward communication pipe (68). Each refrigerant flowing through each windward communication pipe (68) is supplied to each windward main communication space (65) of the second header collecting pipe (60), and is distributed to each windward main heat exchange unit (36). You. Each refrigerant passing through each windward refrigerant flow path group (C1) of each flat tube (31) of each windward main heat exchange section (36) further absorbs heat from the air and evaporates, and the superheated state (that is, gas) (Single-phase state).

    The superheated gas refrigerant joins in the space on the windward side (52) of the first header collecting pipe (50), and is sent from the first main gas pipe (52a) to the gas-side communication pipe (14).

    As shown in FIG. 19, the refrigerant supplied to the second branch unit (92) is diverted to the respective liquid side connection pipes (92b) and from the respective leeward auxiliary spaces (75) of the third header collecting pipe (70). It is distributed to each downwind auxiliary heat exchange section (48). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward auxiliary heat exchange section (48) absorbs heat from air and evaporates. Thereafter, each refrigerant is supplied to each leeward auxiliary communication space (87) of the fourth header collecting pipe (80), and flows into each leeward communication pipe (88). Each refrigerant flowing through each leeward communication pipe (88) is supplied to each leeward main communication space (85) of the fourth header collecting pipe (80), and is distributed to each leeward main heat exchange section (46). Each refrigerant passing through each leeward refrigerant flow path group (C2) of each flat tube (41) of each leeward main heat exchange section (46) further absorbs heat from air and evaporates, and is overheated (ie, gas single phase). State).

    The superheated gas refrigerant joins in the leeward space (72) of the third header collecting pipe (70) and is sent to the gas side connecting pipe (14) together with the refrigerant flowing out of the first main gas pipe (52a). Can be

<Measures to suppress air drift>
By the way, when the outdoor heat exchanger (23) functions as an evaporator, there has conventionally been a problem that the air flowing through the outdoor heat exchanger (23) tends to drift. Specifically, in the outdoor heat exchanger (23), the refrigerant flow path groups (C1, C2) are respectively formed in the two row portions (30, 40), and the refrigerant flow path groups (C1, C2) are formed in parallel. Let the refrigerant flow. Here, in each of the refrigerant flow path groups (C1, C2), the refrigerant in the gas-liquid two-phase state is used for cooling air. For this reason, moisture in the air may condense and form frost on the surfaces of the flat tubes (31, 41) and the fins (32, 42).

    On the other hand, in each of the refrigerant flow path groups (C1, C2), when the refrigerant in the gas-liquid two-phase state further evaporates, it becomes overheated and the temperature rises. Therefore, in the flat tubes (31, 41), in the portion where the superheated refrigerant flows, moisture in the air is less likely to condense, and frost forms on the surfaces of the flat tubes (31, 41) and the fins (32, 42). Hardly occurs.

    For this reason, in the adjacent refrigerant flow path groups (C1, C2), the part where the refrigerant in the liquid state or the gas-liquid two-phase state flows and the part where the superheated refrigerant flows overlap in the air passage direction. This causes a problem that the air flowing through the outdoor heat exchanger (23) tends to drift.

    Specifically, in the adjacent refrigerant flow path groups (C1, C2), for example, when a portion in which a refrigerant in a liquid state or a gas-liquid two-phase state flows overlaps in a direction in which air passes, each flat tube ( 31, 41) and the surface of each fin (32, 42), frost formation is likely to occur as described above. In particular, in the case of the flat tubes (31, 41), the amount of frost tends to increase because the water condensed on the surface tends to stay on the surfaces. In such a state, the flat tubes (31, 41) and the fins (32, 42) of both the leeward row portion (30) and the leeward row portion (40) are continuously frosted, so Tends to increase the ventilation resistance.

    On the other hand, in the adjacent refrigerant flow path groups (C1, C2), when the portions of the superheated region where the refrigerant flows overlap in the air passage direction, the flat tubes (31, 41) and the fins (32, Frost formation hardly occurs on the surface of 42). Therefore, in such a state, there is a problem in that the ventilation resistance of the portion corresponding to the overheated region overlapping in two rows is smaller than that of the other portion, and the air tends to drift to this portion.

    In this way, when air drift occurs, the flat tubes (31, 41) and fins (32, 42) of the entire outdoor heat exchanger (23) cannot be effectively used for heat transfer between the refrigerant and the air, This leads to a decrease in heat exchange efficiency. Therefore, in the present embodiment, in order to prevent such a drift of the air, the superheated regions (S1, S2) of the respective row portions (30, 40) are prevented from overlapping in the air passage direction.

    That is, as shown in FIGS. 19 to 21, in the outdoor heat exchanger (23), as described above, the refrigerant flowing through the leeward refrigerant flow path group (C1) and the leeward refrigerant flow path group (C2) flow The refrigerant and the refrigerant are in opposite directions. For this reason, the superheated area (S1) of the leeward row (30) is formed near the end of the first leeward pipe (31a) of the flat tube (31), and the overheated area of the leeward row (40) is formed. (S2) is formed near the end of the fourth leeward pipe section (41d) of the flat pipe (41). That is, the superheated area (S1) and the superheated area (S2) are located farthest in the longitudinal direction of each flat tube (31, 41). Therefore, it is possible to reliably prevent the superheated region (S1) and the superheated region (S2) from overlapping in the air passage direction, and to prevent the above-described air drift.

    In the outdoor heat exchanger (23), the number and size of the flat tubes (31, 41) and each refrigerant flow are set so that the superheated area (S1) and the superheated area (S2) do not overlap in the air passage direction. Various parameters such as the number and size of the road (C), the amount of circulating refrigerant, and the amount of air flow are designed.

-Effects of Embodiment 2-
Also in the second embodiment, similarly to the first embodiment, the pressure loss of the refrigerant can be reduced.

    As shown in FIGS. 18 to 20, when the outdoor heat exchanger (23) functions as an evaporator, it is possible to prevent the superheated regions (S1, S2) of the refrigerant from overlapping. Thereby, it is possible to suppress the air from drifting only in the superheated regions (S1, S2). As a result, even if frost forms on the surfaces of the flat tubes (31, 41) and fins (32, 42) other than the superheated areas (S1, S2), air can be uniformly flowed throughout the heat exchanger. Therefore, the heat exchange efficiency and the evaporation performance can be improved.

<< Other embodiments >>
In various embodiments of the present disclosure, the following configuration may be adopted.

    In the outdoor heat exchanger (23), the adjacent header collecting pipes (50, 70) and (60, 80) are separately formed, respectively. At least one set of these header collecting pipes is integrated, and The internal space may be divided into two rows.

    In the outdoor heat exchanger (23), the adjacent superheated regions (S1, S2) of the refrigerant flow path groups (C1, C2) of the two rows of flat tubes (31, 41) are not overlapped with each other. For example, in three or more rows of refrigerant flow path groups (C1, C2), adjacent superheated regions may not be overlapped.

    In the outdoor heat exchanger (23), the auxiliary heat exchange area (37, 47) may be omitted.

    The heat exchanger of the present disclosure is an outdoor heat exchanger (23). However, the heat exchanger of the present disclosure may be applied to the indoor heat exchanger (25). In this case, it is preferable that the indoor heat exchanger (25) is, for example, a four-sided heat exchanger mounted in an indoor unit of a ceiling embedded type or a ceiling suspended type. Further, the outdoor heat exchanger (23) and the indoor heat exchanger (25) are not necessarily four-sided and may be three or less.

    As shown in FIG. 7, for example, the heat exchanger according to the present disclosure has separate fins on the windward side and the leeward side so as to correspond to the leeward row (30) and the leeward row (40). 32, 42) are provided. However, for example, as shown in FIG. 21, the flat tubes (31, 41) are arranged in two rows in the air passage direction, while the fins (32, 42) on the windward side and the leeward side are arranged on the windward row section (30). And the leeward row portion (40).

    The fins (32, 42) of the heat exchanger of the present disclosure form a tube insertion portion (32b, 42b) at the edge on the windward side, and the flat tube (31, 41) is formed in the tube insertion portion (32b, 42b). Is inserted. However, the heat exchanger may have a configuration in which a tube insertion portion is formed at the leeward edge of the fins (32, 42), and the flat tubes (31, 41) are inserted into the tube insertion portion. Further, in the fins (32, 42) of the present disclosure, the louvers (32c, 42c) are formed as the heat transfer promoting portions, but the fins (32, 42) bulge in the thickness direction. (A convex portion) or a slit may be used as the heat transfer promoting portion.

    The two row portions (30, 40) of the above embodiment may have different configurations. That is, for example, in two rows of flat tubes (31, 41), the width of each flat tube (31, 41), the interval in the thickness direction (vertical direction) of each flat tube (31, 41), and the width of each flat tube (31, 41) The configuration may be such that the flow path area of the refrigerant flow path (C) of 41), the number of refrigerant flow paths (C) of each flat tube (31, 41), and the like are different from each other. In the two rows of fins (32, 42), the width (length in the air passing direction) of the fins (32, 42), the pitch (interval) in the thickness direction of the fins (32, 42), and the fins (32.42) ) May be different from each other.

    In the air conditioner of the present disclosure, one refrigerant adjustment valve may be provided for each of the plurality of row portions (30, 40). That is, by individually adjusting the opening degrees of these refrigerant adjustment valves, it is possible to individually adjust the amount of refrigerant flowing in parallel to each row (30, 40).

    As described above, the present invention is useful for a heat exchanger.

10 Air conditioner
23 Outdoor heat exchanger (heat exchanger)
28 Liquid branch pipe
29 Gas branch pipe
30 Upwind row (row section)
31 flat tube
32 Fins
33a 1st bend (bend)
33b 2nd bend (bend)
33c 3rd bend (bend)
40 Downwind row (row section)
41 Flat tube
42 Fins
68 Upwind connecting pipe
88 Downwind connecting pipe
C refrigerant channel
S1 Overheat area
S2 Overheating area

Claims (6)

A plurality of flat tubes (31, 41) arranged in parallel with each other and a plurality of refrigerant channels (C) formed therein, and fins (32, 42) joined to the flat tubes (31, 41), respectively. A heat exchanger for exchanging heat between the refrigerant flowing through the refrigerant channel (C) and air,
A plurality of rows (30, 40) having a plurality of the flat tubes (31, 41) are arranged in a direction in which air passes,
The plurality of rows (30, 40) are configured such that the refrigerant flows in parallel in the flat tubes (31, 41) between the plurality of rows (30, 40).
The flat tubes (31, 41) of the plurality of row portions (30, 40) are flattened so that the flat tubes (31, 41) of the row portions (30, 40) adjacent in the air passage direction are along each other. A heat exchanger having at least one bent portion (33a, 33b, 33c) bent in the width direction of the pipe (31, 41). In claim 1,
Each of the row portions (30, 40) has a main heat exchange region corresponding to a plurality of flat tubes (31, 41) arranged in the direction in which the flat tubes (31, 41) of the row portions (30, 40) are arranged. (35, 45) and an auxiliary heat exchange region (37, 47) corresponding to the flat tubes (31, 41) having a smaller number of flat tubes (31, 41) than the main heat exchange region (35, 45). Is formed,
The plurality of row portions (30, 40) include main heat exchange regions (35, 45) and auxiliary heat exchange regions (37, 40) adjacent to each other in the air passage direction between the plurality of row portions (30, 40). 47) The heat exchanger according to (47), wherein the refrigerants are configured to flow in parallel. In claim 2,
The plurality of rows (30, 40) are flattened in each main heat exchange area (35, 45) and each auxiliary heat exchange area (37, 47) between rows (30, 40) adjacent in the air passage direction. The refrigerant flows through the pipes (31, 41) in the same direction.
A gas branch pipe (29) communicating with one end of each flat tube (31, 41) of each of the main heat exchange areas (35, 45) of each of the row sections (30, 40); A liquid branch pipe that communicates with one end of the flat pipe (31, 41) of each of the auxiliary heat exchange areas (37, 47) of the section (30, 40) at one end on the gas branch pipe (29) side. (28)
The other end of each flat tube (31, 41) of each main heat exchange area (35, 45) of each row section (30, 40) and each auxiliary heat exchange area of each row section (30, 40) (37, 47) and a communication pipe (68, 88) communicating with the other end of each flat pipe (31, 41). In claim 1 or 2,
When the plurality of rows (30, 40) function as an evaporator, the flow directions of the refrigerant in the flat tubes (31, 41) between the adjacent rows (30, 40) in the air passage direction are opposite to each other. A heat exchanger characterized by being configured to be as follows. In claim 4,
When the plurality of rows (30, 40) function as the evaporator, the superheated region (S1) of the refrigerant flowing through the flat tubes (31, 41) between the rows (30, 40) adjacent to each other in the air passage direction. , S2) such that they do not overlap each other in the direction of air passage. A refrigerant circuit (20) provided with the heat exchanger (23) according to any one of claims 1 to 5 and performing a refrigeration cycle,
An air conditioner characterized by being configured to switch between an operation in which the heat exchanger (23) functions as an evaporator and an operation in which the heat exchanger (23) functions as a condenser.

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