HEAT EXCHANGER AND AIR CONDITIONER

Abstract

 A heat exchanger of the present disclosure is intended to reduce a pressure loss in an auxiliary heat exchange part.
A plurality of flat tubes (53, 58), a first header collecting pipe (51, 56), and a second header collecting pipe (52, 57) are provided. The flat tube (53, 58) is, at one end thereof, connected to the first header collecting pipe (51, 56), and is, at the other end thereof, connected to the second header collecting pipe (52, 57). Some of the flat tubes (53) forms a main heat exchange part (50), and the other flat tubes (58) forms an auxiliary heat exchange part (55). The number of flat tubes (58) of the auxiliary heat exchange part (55) is less than the number of flat tubes (53) of the main heat exchange part (50). The total cross-sectional area of flow paths (49) per flat tube (58) provided in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of flow paths (49) per flat tube (53) provided in the main heat exchange part (50).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a heat exchanger including flat tubes and fins and configured to exchange heat between fluid flowing through the flat tube and air, and to an air conditioner.

BACKGROUND ART

[0002] Conventionally, a refrigerating apparatus has been known, which is capable of performing a refrigeration cycle by refrigerant circulating through a refrigerant circuit and performing an operation for cooling a target object (e.g., air or water) with refrigerant and an operation for heating the target object with refrigerant. For example, Patent Document 1 discloses an air conditioner including the refrigerating apparatus of this type. In the air conditioner during an air-cooling operation for cooling indoor air, an outdoor heat exchanger functions as a condenser, and an indoor heat exchanger functions as an evaporator. On the other hand, in the air conditioner during an air-heating operation for heating indoor air, the indoor heat exchanger functions as the condenser, and the outdoor heat exchanger functions as the evaporator.

[0003] Patent Document 2 also discloses an air conditioner configured to perform a refrigeration cycle. In a refrigerant circuit of the air conditioner, an outdoor heat exchanger configured to exchange heat between refrigerant and outdoor air is provided. The outdoor heat exchanger is a heat exchanger including two headers each formed in a cylindrical shape, and a plurality of flat heat transfer pipes provided between the headers.

[0004] Moreover, Patent Document 3 also discloses a heat exchanger including headers and flat heat transfer pipes. The heat exchanger disclosed in Patent Document 3 functions as a condenser. In the heat exchanger, a main heat exchange part for condensation and an auxiliary heat exchange part for sub-cooling are formed. While passing through the main heat exchange part, refrigerant flowing into the heat exchanger is condensed into a substantially liquid single-phase state. Then, the refrigerant flows into the auxiliary heat exchange part, and is further cooled.

CITATION LIST

PATENT DOCUMENT

[0005] 

PATENT DOCUMENT 1: Japanese Patent Publication No. 2008-064447

PATENT DOCUMENT 2: Japanese Patent Publication No. H09-014698

PATENT DOCUMENT 3: Japanese Patent Publication No. 2010-025447

SUMMARY OF THE INVENTION

TECHNICAL PROBLEM

[0006] However, in the case where the main heat exchange part for condensation and the auxiliary heat exchange part for sub-cooling are formed in the heat exchanger including the headers and the flat heat transfer pipes (flat tubes), the auxiliary heat exchange part typically has flow paths fewer than those of the main heat exchange part. Thus, there is a possibility that a flow velocity in the auxiliary heat exchange part increases, and therefore a pressure loss in the auxiliary heat exchange part increases.

[0007] The present disclosure has been made in view of the foregoing, and it is an objective of the present disclosure to reduce, in a heat exchanger in which headers and flat tubes are provided and a main heat exchange part(s) for condensation and an auxiliary heat exchange part(s) for sub-cooling are formed, a pressure loss in the auxiliary heat exchange part.

SOLUTION TO THE PROBLEM

[0008] In order to solve the foregoing problem, a first aspect of the invention is intended for a heat exchanger including a plurality of flat tubes (53, 58) arranged in the vertical direction such that side surfaces thereof face each other and each formed with a plurality of flow paths (49) of fluid, and a plurality of fins (54, 59) configured to divide part between adjacent ones of the flat tubes (53, 58) into a plurality of air passages through each of which air flows. The heat exchanger includes a first header collecting pipe (51, 56); and a second header collecting pipe (52, 57). Each flat tube (53, 58) is, at one end thereof, connected to the first header collecting pipe (51, 56), and is, at the other end thereof, connected to the second header collecting pipe (52, 57). Some of the flat tubes (53) form a main heat exchange part (50), and the other flat tubes (58) form an auxiliary heat exchange part (55). The flat tubes (58) forming the auxiliary heat exchange part (55) are fewer than the flat tubes (53) forming the main heat exchange part (50). The total cross-sectional area of flow paths (49) per flat tube (58) in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of flow paths (49) per flat tube (53) in the main heat exchange part (50). If the heat exchanger serves as a condenser, refrigerant is condensed in the main heat exchange part (50), and the refrigerant is sub-cooled in the auxiliary heat exchange part (55).

[0009] In the foregoing configuration, the number of flat tubes (58) forming the auxiliary heat exchange part (55) is less than the number of flat tubes (53) forming the main heat exchange part (50). However, the total cross-sectional area of flow paths (49) per flat tube (58) in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of flow paths (49) per flat tube (53) in the main heat exchange part (50). Thus, if the heat exchanger serves as the condenser, the flow velocity of refrigerant in the auxiliary heat exchange part (55) can be lowered as compared to a heat exchanger in which a single type of flat tubes forms a main heat exchange part and an auxiliary heat exchange part.

[0010] A second aspect of the invention is intended for the heat exchanger of the first aspect of the invention, in which the width (W2) of each flat tube (58) of the auxiliary heat exchange part (55) is greater than the width (W1) of each flat tube (53) of the main heat exchange part (50), and the flow paths per flat tube (58) in the auxiliary heat exchange part (55) is more than the flow paths per flat tube (53) in the main heat exchange part (50).

[0011] In the foregoing configuration, the number of flow paths per flat tube (53, 58) and the width (W1, W2) of the flat tube (53, 58) are adjusted to set the total cross-sectional area of flow paths (49) per flat tube (53, 58).

[0012] A third aspect of the invention is intended for the heat exchanger of the first or second aspect of the invention, in which each flow path (49) is formed with a plurality of grooves in a corresponding one of the flat tubes (53) of the main heat exchange part (50), and each flat tube (58) of the auxiliary heat exchange part (55) is a bare pipe.

[0013] In the foregoing configuration, since the grooves (49a) are formed in the flat tube (53) for the main heat exchange part (50), the surface area per refrigerant flow path (49) can be increased.

[0014] A fourth aspect of the invention is intended for the heat exchanger of any one of the first to third aspects of the invention, in which each fin (236) is formed in such a plate shape that a plurality of cut parts (245) into each of which a corresponding one of the flat tubes (53, 58) is inserted are provided, the fins (236) are arranged at predetermined intervals in an extension direction of the flat tubes (53, 58), each flat tube (53, 58) is sandwiched between peripheral edge parts of a corresponding one of the cut parts (245) of the fins (236), and, in each fin (236), part between adjacent ones of the cut parts (245) arranged in the vertical direction forms a heat transfer part (237).

[0015] In the foregoing configuration, the plurality of fins (236) each formed in a plate shape are arranged at the predetermined intervals in the extension direction of the flat tubes (53, 58). In each fin (236), the plurality of cut parts (245) into each of which a corresponding one of the flat tubes (53, 58) is inserted are formed. The flat tube (53, 58) is sandwiched between the peripheral edge parts of a corresponding one of the cut parts (245) of the fin (236). Moreover, in the fin (236), the part between adjacent ones of the cut parts (245) arranged in the vertical direction forms the heat transfer part (237).

[0016] A fifth aspect of the invention is intended for the heat exchanger of the fourth aspect of the invention, in which an end of each flat tube (53, 58) in a width direction thereof is aligned with an end of a corresponding one of the cut parts (245) on an open side thereof.

[0017] In the foregoing configuration, the end of the flat tube (53, 58) in the width direction thereof is aligned with the end of the cut part (245) on the inlet side thereof. Thus, when a brazing material for joining the fin (236) and the flat tube (53, 58) together is applied, the brazing material can be easily set on a side close to the cut part (245).

[0018] A sixth aspect of the invention is intended for an air conditioner including a refrigerant circuit (20) provided with the heat exchanger (40) of any one of claims 1-5. Refrigerant circulates to perform a refrigeration cycle in the refrigerant circuit (20).

[0019] In the foregoing configuration, the heat exchanger is connected to the refrigerant circuit (20). In the heat exchanger, refrigerant circulating through the refrigerant circuit (20) flows through the flow paths (49) of the flat tubes (53, 58) to exchange heat with air flowing through air passages.

ADVANTAGES OF THE INVENTION

[0020] According to the first aspect of the invention, if the heat exchanger serves as the condenser, the flow velocity of refrigerant in the auxiliary heat exchange part (55) can be lowered, and therefore a pressure loss in the auxiliary heat exchange part (55) can be reduced.

[0021] According to the second aspect of the invention, the total cross-sectional area of flow paths (49) in the flat tube (53) for the main heat exchange part (50) and the total cross-sectional area of flow paths (49) in the flat tube (58) for the auxiliary heat exchange part (55) can be easily set. For example, even if the flow paths (49) for the main heat exchange part (50) and the auxiliary heat exchange part (55) are different from each other in shape, and it is difficult to identify the difference in shape of the flow path (49) with eyes, the flat tube (53) for the main heat exchange part (50) and the flat tube (58) for the auxiliary heat exchange part (55) are different from each other in width (W1, W2), and therefore both pipes (53, 58) can be easily identified with eyes.

[0022] According to the third aspect of the invention, in the flat tube (53) for the main heat exchange part (50), a heat exchange efficiency in the main heat exchange part (50) can be improved. Moreover, in the flat tube (58) for the auxiliary heat exchange part (55), a pressure loss due to a pipe shape can be further reduced.

[0023] According to the fifth aspect of the invention, the brazing material for joining the fin (236) and the flat tube (53, 58) together can be easily set, and therefore it can be further ensured that the fin (236) and the flat tube (53, 58) can be joined together. Moreover, the end of the flat tube (53, 58) is aligned with the end of the cut part (245) on the open side thereof. Thus, if the flat tubes (53, 58) having different widths are used, the depth of the cut part (245) may be set corresponding to the flat tube (58) having a greater width. That is, even if plural types of flat tubes (53, 58) having different widths are used, the common fin (236) can be used.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 

[FIG. 1] FIG. 1 is a refrigerant circuit diagram of an air conditioner of a first embodiment, and illustrates a state in an air-cooling operation.

[FIG. 2] FIG. 2 is a refrigerant circuit diagram of the air conditioner of the first embodiment, and illustrates a state in an air-heating operation.

[FIG. 3] FIG. 3 is a schematic perspective view of a heat exchanger unit forming an outdoor heat exchanger of the first embodiment.

[FIG. 4] FIG. 4 is a schematic front view of the heat exchanger unit forming the outdoor heat exchanger of the first embodiment.

[FIG. 5] FIG. 5 is an enlarged perspective view of a main part of the heat exchanger unit of the first embodiment in the state in which part of the main part is not shown.

[FIG. 6] FIG. 6 is a schematic view illustrating an example of a cross-sectional shape of a flat tube.

[FIG. 7] FIG. 7A is a view illustrating an example of a cross-sectional shape of a refrigerant flow path in the flat tube for a main heat exchange part. FIG. 7B is a view illustrating an example of a cross-sectional shape of a refrigerant flow path in the flat tube for an auxiliary heat exchange part.

[FIG. 8] FIG. 8 is an view illustrating part of a cross section of a heat exchanger of a first variation of the first embodiment.

[FIG. 9] FIG. 9 is a schematic perspective view of a fin provided in the heat exchanger of the first variation.

[FIG. 10] FIGS. 10A and 10B are views illustrating a heat transfer part provided in the fin of the heat exchanger of the first variation. FIG. 10A is the front view of the heat transfer part. FIG. 10B is the cross-sectional view along a B-B line illustrated in FIG. 10A.

[FIG. 11] FIG. 11A is a partial cross-sectional view of a heat exchanger of a second variation. FIG. 11B is a cross-sectional view of a fin along a V-V line illustrated in FIG. 11A.

[FIG. 12] FIG. 12 is a view illustrating part of a cross section of a heat exchanger of a third variation of the first embodiment.

[FIG. 13] FIGS. 13A and 13B are views illustrating a main part of a fin of the heat exchanger of the third variation. FIG. 13A is the front view of the fin. FIG. 13B is the cross-sectional view along a G-G line illustrated in FIG. 13A.

[FIG. 14] FIG. 14A is a partial cross-sectional view of a heat exchanger of a fourth variation. FIG. 14B is a cross-sectional view of a fin along an X-X line illustrated in FIG. 14A.

[FIG. 15] FIG. 15 is a front view illustrating a schematic configuration of an outdoor heat exchanger of a second embodiment.

[FIG. 16] FIG. 16 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger of the second embodiment.

[FIG. 17] FIG. 17 is a front view illustrating a schematic configuration of an outdoor heat exchanger of a third embodiment.

[FIG. 18] FIG. 18 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger of the third embodiment.

[FIG. 19] FIG. 19 is a front view illustrating a schematic configuration of an outdoor heat exchanger of a fourth embodiment.

[FIG. 20] FIG. 20 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger of the fourth embodiment.

[FIG. 21] FIG. 21 is a front view illustrating a schematic configuration of an outdoor heat exchanger of a fifth embodiment.

[FIG. 22] FIG. 22 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger of the fifth embodiment.

[FIG. 23] FIG. 23 is a front view illustrating a schematic configuration of an outdoor heat exchanger of a sixth embodiment.

[FIG. 24] FIG. 24 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger of the sixth embodiment.

[FIG. 25] FIG. 25 is a partial cross-sectional view of an outdoor heat exchanger of a seventh embodiment.

DESCRIPTION OF EMBODIMENTS

[0025] Embodiments of the present disclosure will be described below with reference to drawings. Note that the embodiments described below will be set forth merely for the purpose of preferred examples in nature, and are not intended to limit the scope, applications, and use of the invention.

<<First Embodiment of the Invention>>

[0026] A first embodiment of the present disclosure will be described. The present embodiment is intended for an air conditioner including a refrigerating apparatus.

<Entire Configuration of Air Conditioner>

[0027] FIG. 1 is a refrigerant circuit diagram of an air conditioner (10) of the first embodiment of the present disclosure, and illustrates a state in an air-cooling operation. Moreover, FIG. 2 is a refrigerant circuit diagram of the air conditioner (10) of the first embodiment, and illustrates a state in an air-heating operation. Referring to FIG. 1, the air conditioner (10) of the present embodiment includes a single indoor unit (12) which is a utilization-side unit, and a single outdoor unit (11) which is a heat-source-side unit. In the air conditioner (10), the outdoor unit (11) and the indoor unit (12) are connected together by pipes to form a refrigerant circuit (20).

[0028] Note that the number of indoor units (12) and outdoor units (11) has been set forth merely for the purpose of an example. That is, in the air conditioner (10) of the present embodiment, a plurality of indoor units (12) may be connected to a single outdoor unit (11) to form a refrigerant circuit (20). Alternatively, a plurality of outdoor units (11) and a plurality of indoor units (12) may be connected together to form a refrigerant circuit (20).

[0029] In the refrigerant circuit (20), the followings are provided: a compressor (31); an outdoor heat exchanger (40) which is a heat-source-side heat exchanger; an indoor heat exchanger (32) which is a utilization-side heat exchanger; an expansion valve (33); and a four-way valve (34). The compressor (31), the outdoor heat exchanger (40), the expansion valve (33), and the four-way valve (34) are accommodated in the outdoor unit (11). The indoor heat exchanger (32) is accommodated in the indoor unit (12). Although not shown in the figure, an outdoor fan configured to supply outdoor air to the outdoor heat exchanger (40) is provided in the outdoor unit (11), and an indoor fan configured to supply indoor air to the indoor heat exchanger (32) is provided in the indoor unit (12).

[0030] The compressor (31) is a hermetic rotary compressor or a hermetic scroll compressor. In the refrigerant circuit (20), an outlet pipe of the compressor (31) is connected to a first port of the four-way valve (34) through a pipe, and an inlet pipe of the compressor (31) is connected to a second port of the four-way valve (34) through a pipe.

[0031] The outdoor heat exchanger (40) includes first and second header members (46, 47) standing upright, and a plurality of heat transfer pipes (hereinafter also referred to as "flat tubes") (53, 58). The outdoor heat exchanger (40) is configured to exchange heat between refrigerant and outdoor air. The structure of the outdoor heat exchanger (40) will be described in detail later. The indoor heat exchanger (32) is a so-called "cross-fin type fin- and-tube heat exchanger," and is configured to exchange heat between refrigerant and indoor air.

[0032] The expansion valve (33) is a so-called "electronic expansion valve (33)." The four-way valve (34) includes four ports, and switches between a first state (state illustrated in FIG. 1) in which the first port communicates with a third port and the second port communicates with a fourth port and a second state (state illustrated in FIG. 2) in which the first port communicates with the fourth port and the second port communicates with the third port.

[0033] In the refrigerant circuit (20), a first gas pipe (21), a second gas pipe (22), and a liquid pipe (23) are provided. The first gas pipe (21) is, at one end thereof, connected to the third port of the four-way valve (34), and is, at the other end thereof, connected to an upper end part of the first header member (46) of the outdoor heat exchanger (40). The second gas pipe (22) is, at one end thereof, connected to the fourth port of the four-way valve (34), and is, at the other end thereof, connected to a gas end of the indoor heat exchanger (32). The liquid pipe (23) is, at one end thereof, connected to a lower end part of a first header collecting pipe (56) which will be described later, and is, at the other end thereof, connected to a liquid end of the indoor heat exchanger (32). The expansion valve (33) is provided in the middle of the liquid pipe (23).

<Structure of Outdoor Heat Exchanger>

[0034] The structure of the outdoor heat exchanger (40) will be described in detail with reference to FIGS. 3, 4, and 5. FIG. 3 is a schematic perspective view of a heat exchanger unit forming the outdoor heat exchanger of the first embodiment. FIG. 4 is a schematic front view of the heat exchanger unit forming the outdoor heat exchanger of the first embodiment. FIG. 5 is an enlarged perspective view of a main part of the heat exchanger unit of the first embodiment in the state in which part of the main part is not shown.

[0035] The outdoor heat exchanger (40) of the present embodiment includes a single heat exchanger unit (45).

[0036] Referring to FIGS. 3 and 4, the heat exchanger unit (45) forming the outdoor heat exchanger (40) includes the single first header member (46), the single second header member (47), the plurality of heat transfer pipes (53, 58), and a plurality of fins (54, 59). The first header member (46), the second header member (47), the flat tubes (53, 58), and the fins (54, 59) are members made of an aluminum alloy, and are joined together by brazing. The fin (54, 59) divides part between adjacent ones of the flat tubes (53, 58) into a plurality of air passages through each of which air flows.

[0037] The first header member (46) and the second header member (47) are each formed in an elongated hollow cylindrical shape closed at both ends thereof. In FIG. 4, the first header member (46) stands upright at the left of the heat exchanger unit (45), and the second header member (47) stands upright at the right of the heat exchanger unit (45). That is, the first header member (46) and the second header member (47) are mounted in such an attitude that the axial directions thereof are along the vertical direction.

[0038] Referring to FIG. 5, the heat transfer pipes (53, 58) are each formed in a flat shape, and a plurality of refrigerant flow paths (49) are formed in line in each of the heat transfer pipes (53, 58). The heat transfer pipes (53, 58) are hereinafter also referred to as "flat tubes." FIG. 6 is a schematic view illustrating an example of a cross-sectional shape of the flat tube (53, 58). In this example, the width (W2) of the flat tube (58) is, referring to FIG. 6, greater than the width (W1) of the flat tube (53). Moreover, the number of flow paths per flat tube (58) is greater than the number of flow paths per flat tube (53).

[0039] FIG. 7A is a view illustrating an example of a cross-sectional shape of the refrigerant flow path (49) in the flat tube (53) for a main heat exchange part (50) which will be described later, and FIG. 7B is a view illustrating an example of a cross-sectional shape of the refrigerant flow path (49) in the flat tube (58) for an auxiliary heat exchange part (55) which will be described later. In the example illustrated in FIGS. 7A and 7B, a plurality of grooves (49a) are formed in each of the refrigerant flow paths (49) of the flat tube (53), whereas the flat tube (58) is a so-called "bare pipe (smooth inner pipe)" having a circular cross section. That is, no groove (49a) is formed in each of the refrigerant flow paths (49) of the flat tube (58). Note that, in this example, each of the refrigerant flow paths (49) of the flat tube (58) has a diameter of about 0.5 mm. Needless to say, such cross-sectional shapes of the refrigerant flow path (49) are set forth merely for the purpose of examples, and other shapes (e.g., a rectangular cross section illustrated in FIG. 6) may be employed.

[0040] In the heat exchanger unit (45), the flat tubes (53, 58) are arranged at predetermined intervals in the axial direction of the first and second header members (46, 47) in such an attitude that the axial direction of the flat tube (53, 58) is along the horizontal direction and side surfaces of the flat tubes (53, 58) face each other. That is, in the heat exchanger unit (45), the flat tubes (53, 58) are arranged parallel to each other between the first header member (46) and the second header member (47). One end part of the flat tube (53, 58) is inserted into the first header member (46), and the other end part of the flat tube (53, 58) is inserted into the second header member (47). Each of the refrigerant flow paths (49) in the flat tube (53, 58) communicates, at one end thereof, with an internal space of the first header member (46), and communicates, at the other end thereof, with an internal space of the second header member (47).

[0041] The fin (54, 59) is provided between adjacent ones of the flat tubes (53, 58). The fin (54, 59) is formed in a corrugated plate shape meandering up and down, and is mounted in such an attitude that a ridge line of such a wave shape is along the front-back direction (direction perpendicular to the plane of paper of FIG. 4) of the heat exchanger unit (45). In the heat exchanger unit (45), air passes in the direction perpendicular to the plane of paper of FIG. 4.

[0042] Referring to FIG. 4, a discoid partition plate (48) is provided in the first header member (46). The internal space of the first header member (46) is horizontally divided by the partition plate (48). On the other hand, the internal space of the second header member (47) is a single undivided space.

[0043] In the heat exchanger unit (45), the upper part relative to the partition plate (48) forms the main heat exchange part (50), and the lower part relative to the partition plate (48) forms the auxiliary heat exchange part (55).

[0044] Specifically, in the first header member (46), the upper part relative to the partition plate (48) forms a first header collecting pipe (51) of the main heat exchange part (50), and the lower part relative to the partition plate (48) forms the first header collecting pipe (56) of the auxiliary heat exchange part (55). Of the flat tubes (53, 58) provided in the heat exchanger unit (45), the flat tubes (53) connected to the first header collecting pipe (51) of the main heat exchange part (50) are for the main heat exchange part (50), and the flat tubes (58) connected to the first header collecting pipe (56) of the auxiliary heat exchange part (55) are for the auxiliary heat exchange part (55). Of the fins (54, 59) provided in the heat exchanger unit (45), the fins (54) each provided between adjacent ones of the flat tubes (53) of the main heat exchange part (50) are for the main heat exchange part (50), and the fins (59) each provided between adjacent ones of the flat tubes (58) of the auxiliary heat exchange part (55) are for the auxiliary heat exchange part (55). In the second header member (47), part of the second header member (47) to which the flat tubes (53) of the main heat exchange part (50) are inserted forms a second header collecting pipe (52) of the main heat exchange part (50), and part of the second header member (47) to which the flat tubes (58) of the auxiliary heat exchange part (55) are inserted forms a second header collecting pipe (57) of the auxiliary heat exchange part (55).

[0045] In the outdoor heat exchanger (40), the width (W1) of the flat tube (53) of the main heat exchange part (50), the number of refrigerant flow paths (49), the cross-sectional area of the refrigerant flow path (49), the number of flat tubes (53), etc. are determined based on requirements of a heat exchange capacity required for air-cooing and air-heating. In general, the number of flat tubes (53, 58) which can be provided in the outdoor heat exchanger (40) is limited. Thus, e.g., the number of flat tubes (58) is the number obtained by subtracting the number of flat tubes (53) from the maximum possible number. Then, based on the determined number of flat tubes (53, 58), the width (W2) of the flat tube (58), the number of refrigerant flow paths (49), and the cross-sectional area of the refrigerant flow path (49) are set depending on the capacity required for the auxiliary heat exchange part (55).

[0046] Specifically, in the outdoor heat exchanger (40) of the present embodiment, the number of flat tubes (58) of the auxiliary heat exchange part (55) is less than the number of flat tubes (53) of the main heat exchange part (50). The total cross-sectional area of refrigerant flow paths (49) per flat tube (58) provided in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of refrigerant flow paths (49) per flat tube (53) provided in the main heat exchange part (50).

[0047] In this example, sixty flat tubes (53, 58) are provided in the outdoor heat exchanger (40). The number of flat tubes (58) of the auxiliary heat exchange part (55) is ten, and the number of flat tubes (53) of the main heat exchange part (50) is fifty. That is, the number of flat tubes (58) of the auxiliary heat exchange part (55) is one-fifth of the number of flat tubes (53) of the main heat exchange part (50). Note that the number of flat tubes (53, 58) illustrated in FIGS. 3 and 4 is different from the actual number of flat tubes (53, 58) provided in the outdoor heat exchanger (40).

[0048] As described above, in the refrigerant circuit (20), the first gas pipe (21) is connected to the upper end part of the first header member (46), and the liquid pipe (23) is connected to a lower end part of the first header member (46) (see FIG. 1). That is, in the outdoor heat exchanger (40), the first gas pipe (21) is connected to the first header collecting pipe (51) of the main heat exchange part (50), and the liquid pipe (23) is connected to the first header collecting pipe (56) of the auxiliary heat exchange part (55).

<Operations>

[0049] The operations of the air conditioner (10) will be described. The air conditioner (10) performs the air-cooling operation which is a cooling process and the air-heating operation which is a heating process.

<Air-Cooling Operation>

[0050] The process in the air-cooling operation of the air conditioner (10) will be described with reference to FIG. 1.

[0051] In the air-cooling operation, the four-way valve (34) is set at the first state. Moreover, the degree of opening of the expansion valve (33) is adjusted such that the degree of superheat of refrigerant flowing out from the gas end of the indoor heat exchanger (32) reaches a predetermined target value (e.g., 5°C). Further, in the air-cooling operation, outdoor air is supplied to the outdoor heat exchanger (40) by the outdoor fan, and indoor air is supplied to the indoor heat exchanger (32) by the indoor fan.

[0052] In the refrigerant circuit (20), refrigerant discharged from the compressor (31) passes through the four-way valve (34) and the first gas pipe (21) in this order, and then flows into the first header collecting pipe (51) of the main heat exchange part (50). The refrigerant flowing into the first header collecting pipe (51) flows into the flat tubes (53) of the main heat exchange part (50). While passing through each of the refrigerant flow paths (49) of the flat tubes (53), the refrigerant is condensed by dissipating heat to outdoor air. After passing through the flat tubes (53), the refrigerant flows into the second header collecting pipe (52) of the main heat exchange part (50), and then flows down to the second header collecting pipe (57) of the auxiliary heat exchange part (55). The refrigerant flowing into the second header collecting pipe (57) flows into the flat tubes (58) of the auxiliary heat exchange part (55). While passing through each of the refrigerant flow paths (49) of the flat tubes (58), the refrigerant enters a sub-cooling state by dissipating heat to outdoor air. After passing through the flat tubes (58), the refrigerant flows into the first header collecting pipe (56) of the auxiliary heat exchange part (55).

[0053] The refrigerant flowing into the liquid pipe (23) from the first header collecting pipe (56) of the auxiliary heat exchange part (55) is expanded (i.e., the pressure of refrigerant is reduced) upon passage of the expansion valve (33), and then flows into the liquid end of the indoor heat exchanger (32). The refrigerant flowing into the indoor heat exchanger (32) is evaporated by absorbing heat from indoor air. The indoor unit (12) supplies taken indoor air to the indoor heat exchanger (32), and sends indoor air cooled by the indoor heat exchanger (32) back to a room.

[0054] The refrigerant evaporated in the indoor heat exchanger (32) flows into the second gas pipe (22) from the gas end of the indoor heat exchanger (32). Subsequently, the refrigerant is sucked into the compressor (31) through the four-way valve (34). The compressor (31) compresses the taken refrigerant and then discharge the compressed refrigerant.

<Air-Heating Operation>

[0055] The process in the air-heating operation of the air conditioner (10) will be described with reference to FIG. 2.

[0056] In the air-heating operation, the four-way valve (34) is set at the second state. Moreover, the degree of opening of the expansion valve (33) is adjusted such that the degree of superheat of refrigerant flowing out from the outdoor heat exchanger (40) reaches a predetermined target value (e.g., 5°C). Further, in the air-heating operation, outdoor air is supplied to the outdoor heat exchanger (40) by the outdoor fan, and indoor air is supplied to the indoor heat exchanger (32) by the indoor fan.

[0057] In the refrigerant circuit (20), refrigerant discharged from the compressor (31) passes through the four-way valve (34) and the second gas pipe (22) in this order, and then flows into the gas end of the indoor heat exchanger (32). The refrigerant flowing into the indoor heat exchanger (32) is condensed by dissipating heat to indoor air. The indoor unit (12) supplies taken indoor air to the indoor heat exchanger (32), and sends indoor air heated by the indoor heat exchanger (32) back to a room.

[0058] The refrigerant flowing into the liquid pipe (23) from the liquid end of the indoor heat exchanger (32) is expanded (i.e., the pressure of refrigerant is reduced) upon passage of the expansion valve (33), and then flows into the first header collecting pipe (56) of the auxiliary heat exchange part (55). The refrigerant flowing into the first header collecting pipe (56) of the auxiliary heat exchange part (55) flows into the flat tubes (58) of the auxiliary heat exchange part (55). While passing through the refrigerant flow paths (49), the refrigerant flowing into each of the flat tubes (58) absorbs heat from outdoor air, and part of the refrigerant is evaporated. The refrigerant evaporated in the flat tubes (58) flows into the second header collecting pipe (52), and then flows into the flat tubes (53) of the main heat exchange part (50). While passing through the refrigerant flow paths (49), the refrigerant flowing into each of the flat tubes (53) is evaporated by absorbing heat from outdoor air.

[0059] After passing through the flat tubes (53) of the main heat exchange part (50), the refrigerant flows into the first header collecting pipe (51) of the main heat exchange part (50), and then flows into the first gas pipe (21). After passing through the four-way valve (34), the refrigerant flowing through the first gas pipe (21) is sucked into the compressor (31). The compressor (31) compresses the taken refrigerant and discharges the compressed refrigerant.

<Advantages of the Present Embodiment>

[0060] In the present embodiment, the number of flat tubes (58) forming the auxiliary heat exchange part (55) is less than the number of flat tubes (53) forming the main heat exchange part (50). However, the total cross-sectional area of refrigerant flow paths (49) per flat tube (58) provided in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of refrigerant flow paths (49) per flat tube (53) provided in the main heat exchange part (50). Thus, in the case where the heat exchanger serves as a condenser, the flow velocity of refrigerant in the auxiliary heat exchange part (55) can be lowered as compared to, e.g., a heat exchanger (hereinafter, for the sake of simplicity of description, referred to as a "conventional heat exchanger") in which a single type of flat tubes forms a main heat exchanger part and an auxiliary heat exchange part. Consequently, according to the present embodiment, a pressure loss in the auxiliary heat exchange part (55) can be reduced.

[0061] In the present embodiment, the number of flow paths per flat tube (53, 58) and the width (W1, W2) of the flat tube (53, 58) are adjusted so that the total cross-sectional area of refrigerant flow paths (49) per flat tube (53, 58) can be set. Thus, the total cross-sectional area of refrigerant flow paths (49) in the flat tube (53) for the main heat exchange part (50) and the total cross-sectional area of refrigerant flow paths (49) in the flat tube (58) for the auxiliary heat exchange part (55) can be easily set.

[0062] In the present embodiment, the grooves (49a) are formed in each of the refrigerant flow paths (49) of the flat tube (53) in the main heat exchange part (50). Thus, in the flat tube (53), the surface area per refrigerant flow path (49) can be increased. That is, a heat exchange efficiency in the main heat exchange part (50) can be improved.

[0063] Since the flat tube (58) of the auxiliary heat exchange part (55) is the so-called "bare pipe," a pressure loss due to a pipe shape can be reduced as compared to the flat tube (53) of the main heat exchange part (50).

[0064] The refrigerant flow path (49) has, as described above, an extremely-small diameter. Thus, when the outdoor heat exchanger (40) is manufactured at a factory, if, e.g., flat tubes having the same width form a main heat exchange part and an auxiliary heat exchange part, it is difficult to identify, with eyes, the presence/absence of the grooves (49a) of the refrigerant flow path (49). However, in the present embodiment, since the flat tube (53) for the main heat exchange part (50) and the flat tube (58) for the auxiliary heat exchange part (55) have the different widths (W1, W2), the presence/absence of the grooves (49a) of the refrigerant flow path (49) can be easily identified.

<<First Variation of First Embodiment>>

[0065] The configuration of the fins (54, 59) has been set forth merely for the purpose of an example, and various types of fins may be employed for the heat exchanger (40). For example, a fin illustrated in FIG. 8 may be employed, instead of the fins (54, 59). FIG. 8 is a view illustrating part of a cross section of a heat exchanger (40) of a first variation of the first embodiment. A fin (235) is a corrugated fin meandering up and down, and is arranged between adjacent ones of flat tubes (heat transfer pipes) (53, 58) which are respectively at the top and bottom of the fin (235). Although will be described in detail later, a plurality of heat transfer parts (237) and a plurality of middle plate parts (241) are formed in the fin (235). In the fin (235), the middle plate parts (241) are joined to the flat tube (53, 58) by brazing.

<Configuration of Fin>

[0066] FIG. 9 is a schematic perspective view of the fin (235) provided in the heat exchanger (40) of the first variation. Referring to FIG. 9, the fin (235) is the corrugated fin formed in such a manner that a metal plate having a uniform width is bent, and is in the shape meandering up and down. In the fin (235), the heat transfer parts (237) and the middle plate parts (241) are alternately formed along an extension direction of the flat tube (53, 58). That is, in the fin (235), the plurality of heat transfer parts (237) arranged in the extension direction of the flat tube (53, 58) are provided between the adjacent ones of the flat tubes (53, 58). Moreover, in the fin (235), protruding plate parts (242) are formed. Note that louvers (250, 260, 270) and a water guide rib (271) which will be described later are not shown in FIG. 9.

[0067] The heat transfer part (237) is a plate-shaped part extending from one of adjacent ones of the flat tubes (53, 58) to the other one of the adjacent ones of the flat tubes (53, 58). In the heat transfer part (237), an end part thereof on a windward side is a front edge (238). Although not shown in FIG. 9, the plurality of louvers (250, 260) are formed in the heat transfer part (237). The middle plate part (241) is a plate-shaped part along flat side surfaces of the flat tubes (53, 58), and is continuous to upper ends of adjacent ones of the heat transfer parts (237) or lower ends of adjacent ones of the heat transfer parts (237). The angle formed between the heat transfer part (237) and the middle plate part (241) is the substantially right angle.

[0068] The protruding plate part (242) is a plate-shaped part continuously formed with an end part of the heat transfer part (237) on a leeward side. The protruding plate part (242) is formed in a vertically-elongated plate shape, and protrudes beyond the flat tube (53, 58) toward the leeward side. An upper end of the protruding plate part (242) upwardly protrudes beyond the upper end of the heat transfer part (237), and a lower end of the protruding plate part (242) downwardly protrudes beyond the lower end of the heat transfer part (237). Referring to FIG. 8, in the outdoor heat exchanger (40), adjacent ones of the protruding plate parts (242) of the fins (235) sandwiching the flat tube (53, 58) at the top and bottom thereof contact each other. In the protruding plate part (242) of the fin (235), the water guide rib (271) is formed. The water guide rib (271) is an elongated recessed groove vertically extending along an end part of the protruding plate part (242) on the leeward side.

[0069] FIGS. 10A and 10B are views illustrating the heat transfer part (237) provided in the fin (235) of the outdoor heat exchanger (40) of the first variation. FIG. 10A is a front view of the heat exchange part, and FIG. 10B is a cross-sectional view along a B-B line illustrated in FIG. 10A. Referring to FIGS. 10A and 10B, in the heat transfer part (237) and the protruding plate part (242) of the fin (235), the plurality of louvers (250, 260, 270) are formed. The louver (250, 260, 270) is formed in such a manner that part of the heat transfer part (237) or the protruding plate part (242) is cut and is folded up. That is, the louvers (250, 260, 270) are formed in such a manner that a plurality of slit-shaped cut is formed in the heat transfer part (237) and the protruding plate part (242) and part between adjacent ones of the cuts is plastically deformed by twisting.

<<Second Variation of First Embodiment>>

[0070] FIG. 11A is a partial cross-sectional view of a heat exchanger (40) of a second variation, and FIG. 11B is a cross-sectional view of a fin along a V-V line illustrated in FIG. 11A. In this example, a plurality of waffle parts (251, 252, 253) are formed, instead of the louvers (250, 260, 270) described in the first variation. Referring to FIGS. 11A and 11B, in a heat transfer part (237) and a protruding plate part (242) of a fin (235), the plurality of waffle parts (251, 252, 253) are formed. The waffle part (251, 252, 253) is a protrusion protruding toward a side on which an air passage is formed and formed in a vertically elongated shape. The waffle parts (251, 252, 253) are formed in such a manner that part of the heat transfer part (237) is plastically deformed by, e.g., pressing. The waffle part (251, 252, 253) extends in a direction inclined relative to the vertical direction such that a lower end part of the waffle part (251, 252, 253) is positioned on the leeward side relative to an upper end part thereof.

[0071] The waffle part (251, 252, 253) has a pair of vertically-elongated trapezoidal surfaces (254) and a pair of flat upper and lower triangular surfaces (255). The trapezoidal surfaces (254) are adjacent to each other in an air passage direction so as to form a ridge part (256) forming a ridge line. The triangular surfaces (255) are formed respectively at the top and bottom of the ridge part (256).

[0072] In the heat transfer part (237), the plurality of waffle parts (251, 252, 253) are formed so as to be arranged from the windward side to the leeward side. The waffle parts (251, 252, 253) are the single windward-side waffle part (251) formed on the windward side of the heat transfer part (237), the two leeward-side waffle parts (253) formed on the leeward side of the heat transfer part (237), and the single middle waffle part (252) formed between the windward-side waffle part (251) and the leeward-side waffle part (253). Of the waffle parts (251, 252, 253), the windward-side waffle part (251) is a windward-side protrusion formed on the most windward side. Of the waffle parts (251, 252, 253), the leeward-side waffle part (253) is a leeward-side protrusion formed on the most leeward side.

[0073] An upper end of the windward-side waffle part (251) is positioned lower than that of the leeward-side waffle part (253). Moreover, an upper end of the middle waffle part (252) and the upper end of the leeward-side waffle part (253) are at the substantially same height. The upper end of the windward-side waffle part (251), the upper end of the middle waffle part (252), and the upper ends of the leeward-side waffle part (253) are substantially parallel to a flat surface of a flat tube (53, 58) provided on an upper side thereof.

[0074] A lower end of the windward-side waffle part (251) is positioned higher than that of the leeward-side waffle part (253). The lower end of the windward-side waffle part (251) is inclined such that part of the lower end of the windward-side waffle part (251) on the leeward side is positioned lower than that on the windward side. A lower end of the middle waffle part (252) is also inclined such that part of the lower end of the middle waffle part (252) on the leeward side is positioned lower than that on the windward side. The lower end of the leeward-side waffle parts (253) are substantially parallel to the flat surface of the flat tube (53, 58).

<<Third Variation of First Embodiment>>

[0075] A fin illustrated in FIG. 12 may be employed, instead of the fins (54, 59). FIG. 12 is a view illustrating part of a cross section of a heat exchanger (40) of a third variation of the first embodiment.

<Configuration of Fin>

[0076] Referring to FIG. 12, a fin (236) is an elongated plate-shaped fin formed in such a manner that a metal plate is pressed. In the fin (236), a plurality of elongated cut parts (245) each extending from a front edge (238) of the fin (236) in a width direction of the fin (236) are formed. In the fin (236), the cut parts (245) are formed at predetermined intervals in a longitudinal direction of the fin (236). Part of the cut part (245) on the leeward side forms a pipe insertion part (246). The pipe insertion part (246) has a vertical width substantially equal to the thickness of a flat tube (53, 58). Moreover, the length (depth) of the pipe insertion part (246) is substantially equal to the width of the flat tube (58) having a greater width. Since the depth of the pipe insertion part (246) corresponds, as described above, to the width of the flat tube (58) having a greater width, a single type of fins (236) can be used. That is, plural types of molds are not necessarily prepared for manufacturing of the fins (236), and reduction in manufacturing cost can be expected. The flat tube (53, 58) is inserted into a corresponding one of the pipe insertion parts (246) of the fin (236), and is joined to a peripheral edge part of the pipe insertion part (246) by brazing. In the present embodiment, an end of the flat tube (53, 58) in a width direction thereof is aligned with an end of the cut part (245) on an open side thereof. Since the length of the pipe insertion part (246) corresponds to the width (W2) of the flat tube (58), a clearance is formed on a closed side of the pipe insertion part (246) in the state in which the flat tube (53) is inserted into the pipe insertion part (246).

[0077] For example, the fin (236) and the flat tube (53, 58) are brazed with each other as follows. First, a side of the fin (236) close to the cut part (245) (i.e., the left side as viewed in FIG. 12) faces up. Then, the end of the flat tube (53, 58) in the width direction thereof is set so as to be aligned with the end of the inlet side of the cut part (245) on the open side thereof, more specifically an end of the pipe insertion part (246) on an open side thereof (i.e., the left end as viewed in FIG. 12). A brazing material is applied in a linear shape at a position (A) illustrated in FIG. 12. Note that the application position (A) is illustrated only for one of the flat tubes (53) in FIG. 12, but the same applies to the other flat tubes (53, 58). If an attempt is made to cause the flat tube (53) to contact the deepest part of the pipe insertion part (246), the brazing material drops, upon brazing, into the pipe insertion part (246), and therefore it is difficult to set the brazing material. However, in the present embodiment, since the end of the flat tube (53, 58) in the width direction thereof is aligned with the end of the cut part (245) on the open side thereof as described above, the brazing material can be easily set.

[0078] Subsequently, e.g., the heat exchanger (40) is placed in a heating furnace (not shown in the figure), and the brazing material is melted. This allows the brazing material to flow along the flat tube (53, 58), and therefore the fin (236) and the flat tube (53, 58) are joined together.

[0079] In the fin (236), part between adjacent ones of the cut parts (245) forms a heat transfer part (237), and part of the pipe insertion part (246) on the leeward side forms a leeward-side plate part (247). That is, in the fin (236), a plurality of heat transfer parts (237) adjacent to each other with the flat tube (53, 58) being interposed between adjacent ones of the heat transfer parts (237), and a single leeward-side plate part (247) continuously formed in end parts of the heat transfer parts (237) on the leeward side are provided. In the heat exchanger (40), each of the heat transfer parts (237) of the fin (236) is arranged between adjacent ones of the flat tubes (53, 58) arranged in the vertical direction, and the leeward-side plate part (247) protrudes beyond the flat tubes (53, 58) toward the leeward side.

[0080] FIGS. 13A and 13B are views illustrating a main part of the fin (236) of the heat exchanger (40) of the third variation. FIG. 13A is a front view of the fin (236), and FIG. 13B is a cross-sectional view along a G-G line illustrated in FIG. 13A. Referring to FIG. 13, in the heat transfer part (237) and the leeward-side plate part (247), a plurality of louvers (250, 260) are formed. The louver (250, 260) is formed in such a manner that part of the heat transfer part (237) or the leeward-side plate part (247) is cut and is folded up.

<<Fourth Variation of First Embodiment>>

[0081] FIG. 14A is a partial cross-sectional view of a heat exchanger (40) of a fourth variation, and FIG. 14B is a cross-sectional view of a fin (236) along an X-X line illustrated in FIG. 14A. In this example, waffle parts (251, 252, 253) are, instead of the louvers (250, 260), formed in the plate-shaped fin described in the third variation. The waffle parts (251, 252, 253) has a configuration similar to that described in the second variation.

<<Second Embodiment of the Invention>>

[0082] An outdoor heat exchanger of a second embodiment of the present disclosure will be described. FIG. 15 is a front view illustrating a schematic configuration of the outdoor heat exchanger (40) of the second embodiment. Moreover, FIG. 16 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger (40) of the second embodiment.

[0083] Referring to FIG. 15, the outdoor heat exchanger (40) is divided into three heat exchange parts (350a-350c). Specifically, in the outdoor heat exchanger (40), the first exchange part (350a), the second exchange part (350b), and the third exchange part (350c) are formed in this order from the bottom to the top.

[0084] Referring to FIG. 16, in each of a first header collecting pipe (360) and a second header collecting pipe (370), three communication spaces (361a-361c, 371a-371c) are formed in such a manner that each of inner spaces of the first header collecting pipe (360) and the second header collecting pipe (370) is divided by partition plates (339).

[0085] The communication space (361a-361c) of the first header collecting pipe (360) is further horizontally divided by a partition plate (339). In the communication space (361a-361c) of the first header collecting pipe (360), the lower space is a lower space (362a-362c) which is a first space, and the upper space is an upper space (363a-363c) which is a second space.

[0086] The exchange part (350a-350c) of the outdoor heat exchanger (40) is divided into a main heat exchange region (main heat exchange part) (351a-351c) and an auxiliary heat exchange region (auxiliary heat exchange part) (352a-352c). In the exchange part (350a-350c), eleven flat tubes (53) communicating with a corresponding one of the upper spaces (363a-363c) of the first header collecting pipe (360) form the main heat exchange part (351a-351c), and three flat tubes (58) communicating with a corresponding one of the lower spaces (362a-362c) of the first header collecting pipe (360) form the auxiliary heat exchange part (352a-352c).

[0087] In the present embodiment, the width of the flat tube (58) provided in the auxiliary heat exchange part (352a-352c) is, as in the first embodiment, greater than that of the flat tube (53) provided in the main heat exchange part (351a-351c). Moreover, the number of flow paths per flat tube (58) provided in the auxiliary heat exchange part (352a-352c) is greater than the number of flow paths per flat tube (53) provided in the main heat exchange part (351a-351c). In this example, fins (corrugated fins) (235) are employed as fins. Needless to say, the fins (54, 59) described in the first embodiment or the fins (236) described in the other variations may be employed.

[0088] Referring to FIG. 15, in the outdoor heat exchanger (40), a liquid connection member (380) and a gas header (385) are provided. The liquid connection member (380) and the gas header (385) are attached to the first header collecting pipe (360).

[0089] The liquid connection member (380) includes a single distributor (381) and three thin pipes (382a-382c). A pipe connecting between the outdoor heat exchanger (40) and an expansion valve (33) is connected to a lower end part of the distributor (381). The thin pipe (382a-382c) is, at one end thereof, connected to an upper end part of the distributor (381). In the distributor (381), the pipe connected to the lower end part thereof and the thin pipes (382a-382c) communicate with each other. The thin pipe (382a-382c) is, at the other end, connected to the first header collecting pipe (360), and communicates with a corresponding one of the lower spaces (362a-362c).

[0090] The gas header (385) includes a single main pipe part (386) and three connection pipe parts (387a-387c). The main pipe part (386) is formed in a pipe shape curving in an inverted U-shape at an upper part thereof and having a relatively-large diameter. A pipe connecting between the outdoor heat exchanger (40) and a third port of a four-way valve (34) is connected to an upper end part of the main pipe part (386). A lower end part of the main pipe part (386) is closed. The connection pipe parts (387a-387c) laterally protrude from a straight part of the main pipe part (386).

[0091] According to the foregoing configuration, in the outdoor heat exchanger (40) of the present embodiment, refrigerant flows in a direction indicated by arrows illustrated in FIG. 15 in an air-cooling operation. In an air-heating operation, refrigerant flows in a direction opposite to the direction indicated by the arrows illustrated in FIG. 15.

<<Third Embodiment of the Invention>>

[0092] An outdoor heat exchanger of a third embodiment of the present disclosure will be described. FIG. 17 is a front view illustrating a schematic configuration of the outdoor heat exchanger (40) of the third embodiment. Moreover, FIG. 18 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger (40) of the third embodiment.

[0093] Referring to FIGS. 17 and 18, the outdoor heat exchanger (40) includes a single first header collecting pipe (460), a single second header collecting pipe (470), a plurality of flat tubes (53, 58), and a plurality of fins (235).

[0094] Referring to FIG. 17, the flat tubes (53, 58) of the outdoor heat exchanger (40) are divided for two upper and lower heat exchange regions (451, 452). That is, in the outdoor heat exchanger (40), the upper heat exchange region (451) and the lower heat exchange region (452) are formed. The heat exchange region (451, 452) is horizontally divided into three heat exchange parts (451a-451c, 452a-452c). Specifically, in the upper heat exchange region (451), the first main heat exchange part (451a), the second main heat exchange part (451b), and the third main heat exchange part (451 c) are formed in this order from the bottom to the top. In the lower heat exchange region (452), the first auxiliary heat exchange part (452a), the second auxiliary heat exchange part (452b), and the third auxiliary heat exchange part (452c) are formed in this order from the bottom to the top. As in the foregoing, in the outdoor heat exchanger (40) of the present embodiment, the upper heat exchange region (451) and the lower heat exchange region (452) are each divided into the plurality of heat exchange parts (451a-451c, 452a-452c), the number of which is the same between the upper heat exchange region (451) and the lower heat exchange region (452). Referring to FIG. 18, the main heat exchange part (451a-451c) includes eleven flat tube (53), and the auxiliary heat exchange part (452a-452c) includes three flat tubes (58). Note that the number of heat exchange parts (451 a-451 c, 452a-452c) formed in the heat exchange region (451, 452) may be two or may be equal to or greater than four.

[0095] In the present embodiment, the width of the flat tube (58) provided in the auxiliary heat exchange part (452a-452c) is, as in the first embodiment, greater than that of the flat tube (53) provided in the main heat exchange part (451a-451c). Moreover, the number of flow paths per flat tube (58) provided in the auxiliary heat exchange part (452a-452c) is greater than the number of flow paths per flat tube (53) provided in the main heat exchange part (451a-451c).

[0096] Internal spaces of the first header collecting pipe (460) and the second header collecting pipe (470) are each horizontally divided by a plurality of partition plates (439).

[0097] Specifically, the internal space of the first header collecting pipe (460) is divided into an upper space (461) corresponding to the upper heat exchange region (451) and a lower space (462) corresponding to the lower heat exchange region (452). The upper space (461) is a single space corresponding to all of the main heat exchange parts (451a-451c). That is, the upper space (461) communicates with all of the flat tubes (53) of the main heat exchange parts (451a-455c). The lower space (462) is, by the partition plates (439), further horizontally divided into communication spaces (462a-462c) corresponding to the auxiliary heat exchange parts (452a-452c) such that the number (i.e., three) of the communication spaces (462a-462c) is the same as that of the auxiliary heat exchange parts (452a-452c). That is, in the lower space (462), the first communication space (462a) communicating with the flat tubes (58) of the first auxiliary heat exchange part (452a), the second communication space (462b) communicating with the flat tubes (58) of the second auxiliary heat exchange part (452b), and the third communication space (462c) communicating with the flat tubes (58) of the third auxiliary heat exchange part (452c) are formed.

[0098] The internal space of the second header collecting pipe (470) is horizontally divided into five communication spaces (471a-471e). Specifically, the internal space of the second header collecting pipe (470) is divided into the four communication spaces (471 a, 471b, 471 d, 471e) corresponding to the main heat exchange parts (451b, 451c) and the auxiliary heat exchange parts (452a, 452b) other than the first main heat exchange part (451a) positioned lowermost in the upper heat exchange region (451) and the third auxiliary heat exchange part (452c) positioned uppermost in the lower heat exchange region (452), and into the single communication space (471c) corresponding to both of the first main heat exchange part (451a) and the third auxiliary heat exchange part (452c). That is, in the internal space of the second header collecting pipe (470), the first communication space (471a) communicating with the flat tubes (58) of the first auxiliary heat exchange part (452a), the second communication space (471b) communicating with the flat tubes (58) of the second auxiliary heat exchange part (452b), the third communication space (471 c) communicating with the flat tubes (53, 58) of both of the third auxiliary heat exchange part (452c) and the first main heat exchange part (451a), the fourth communication space (471d) communicating with the flat tubes (53) of the second main heat exchange part (451b), and the fifth communication space (471e) communicating with the flat tubes (53) of the third main heat exchange part (451c) are formed.

[0099] In the second header collecting pipe (470), the fourth communication space (471d) and the fifth communication space (471e) are paired respectively with the first communication space (471a) and the second communication space (471b). Specifically, the first communication space (471a) and the fourth communication space (471d) are paired together, and the second communication space (471b) and the fifth communication space (471e) are paired together. Moreover, in the second header collecting pipe (470), a first communication pipe (472) connecting between the first communication space (471a) and the fourth communication space (471d) and a second communication pipe (473) connecting between the second communication space (471b) and the fifth communication space (471e) are provided. That is, in the outdoor heat exchanger (40) of the present embodiment, the first main heat exchange part (451a) and the third auxiliary heat exchange part (452c) are paired together, the second main heat exchange part (451b) and the first auxiliary heat exchange part (452a) are paired together, and the third main heat exchange part (451 c) and the second auxiliary heat exchange part (452b) are paired together. Note that the number of pairs of the heat exchange parts (451a-451c, 452a-452c) formed in the outdoor heat exchanger (40) is suitably set depending on the height of the outdoor heat exchanger (40) such that the total height of the main heat exchange part (451a-451c) and the auxiliary heat exchange part (452a-452c) which are to be paired together is equal to or lower than about 350 mm (preferably about 300-350 mm).

[0100] As in the foregoing, in the internal space of the second header collecting pipe (470), the communication spaces (471c, 471d, 471e) corresponding to the main heat exchange parts (451a-451c) of the upper heat exchange region (451) are formed such that the number thereof (e.g., three) is the same as that of the main heat exchange parts (451 a-451 c). Moreover, the communication spaces (471 a, 471b, 471c) corresponding to the auxiliary heat exchange parts (452a-452c) of the lower heat exchange region (452) are formed such that the number thereof (e.g., three) is the same as that of the auxiliary heat exchange parts (452a-452c). Further, the communication spaces (471 c, 471 d, 471e) corresponding to the upper heat exchange region (451) and the communication spaces (471a, 471b, 471c) corresponding to the lower heat exchange region (452) communicate with each other.

[0101] Referring to FIG. 17, in the outdoor heat exchanger (40), a liquid connection member (480) and a gas connection member (485) are provided. The liquid connection member (480) and the gas connection member (485) are attached to the first header collecting pipe (460).

[0102] The liquid connection member (480) includes a single distributor (481) and three thin pipes (482a-482c). A pipe connecting between the outdoor heat exchanger (40) and an expansion valve (33) is connected to a lower end part of the distributor (481). The thin pipe (482a-482c) is, at one end thereof, connected to an upper end part of the distributor (481). In the distributor (481), the pipe connected to the lower end part and the thin pipes (482a-482c) communicate with each other. The thin pipe (482a-482c) is, at the other end thereof, connected to the lower space (462) of the first header collecting pipe (460), and communicates with a corresponding one of the communication spaces (462a-462c).

[0103] Referring to FIG. 18, the thin pipe (482a-482c) opens at part of a corresponding one of the communication spaces (462a-462c) close to a lower end thereof. That is, the first thin pipe (482a) opens at part of the first communication space (462a) close to the lower end thereof, the second thin pipe (482b) opens at part of the second communication space (462b) close to the lower end thereof, and the third thin pipe (482c) opens at part of the third communication space (462c) close to the lower end thereof. Note that the length of the thin pipe (482a-482c) is independently set such that the difference in flow rate of refrigerant flowing into the auxiliary heat exchange parts (452a-452c) is reduced as much as possible.

[0104] The gas connection member (485) is formed of a single pipe having a relatively-large diameter. The gas connection member (485) is, at one end thereof, connected to a pipe connecting between the outdoor heat exchanger (40) and a third port of a four-way valve (34). The gas connection member (485) opens, at the other end thereof, part of the upper space (461) close to an upper end thereof in the first header collecting pipe (460).

[0105] According to the foregoing configuration, in the outdoor heat exchanger (40) of the present embodiment, refrigerant flows in a direction indicated by arrows illustrated in FIG. 17 in an air-cooling operation. In an air-heating operation, refrigerant flows in a direction opposite to the direction indicated by the arrows illustrated in FIG. 17.

<<Fourth Embodiment of the Invention>>

[0106] An outdoor heat exchanger of a fourth embodiment of the present disclosure will be described. FIG. 19 is a front view illustrating a schematic configuration of the outdoor heat exchanger (40) of the fourth embodiment. Moreover, FIG. 20 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger (40) of the fourth embodiment.

[0107] Referring to FIG. 19, flat tubes (53, 58) of the outdoor heat exchanger (40) are, as in the third embodiment, horizontally divided for an upper heat exchange region (451) and a lower heat exchange region (452). The upper heat exchange region (451) is divided into three main heat exchange parts (451a-451c) arranged in the vertical direction, and the lower heat exchange region (452) is formed of a single auxiliary heat exchange part (452a). That is, in the upper heat exchange region (451), the first main heat exchange part (451a), the second main heat exchange part (451b), and the third main heat exchange part (451c) are formed in this order from the bottom to the top. Referring to FIG. 20, the main heat exchange part (451a-451c) includes eleven flat tubes (53), and the auxiliary heat exchange part (452a) includes nine flat tubes (58). Note that the number of main heat exchange parts (451a-451c) formed in the upper heat exchange region (451) may be two or may be equal to or greater than four.

[0108] Internal spaces of a first header collecting pipe (460) and a second header collecting pipe (470) are each horizontally divided by partition plates (439).

[0109] In the present embodiment, the width of the flat tube (58) provided in the auxiliary heat exchange part (452a) is, as in the first embodiment, greater than that of the flat tube (53) provided in the main heat exchange part (451a-451c). Moreover, the number of flow paths per flat tube (58) provided in the auxiliary heat exchange part (452a) is greater than the number of flow paths per flat tube (53) provided in the main heat exchange part (451a-451c).

[0110] Specifically, the internal space of the first header collecting pipe (460) is divided into an upper space (461) corresponding to the upper heat exchange region (451), and a lower space (462) (communication space (462a)) corresponding to the lower heat exchange region (452). The upper space (461) is a single space corresponding to all of the main heat exchange parts (451a-451c). That is, the upper space (461) communicates with all of the flat tubes (53) of the main heat exchange parts (451a-451c). The lower space (462) (communication space (462a)) is a single space corresponding to the single auxiliary heat exchange part (452a), and communicates with the flat tubes (58) of the auxiliary heat exchange part (452a).

[0111] The internal space of the second header collecting pipe (470) is horizontally divided into four communication spaces (471a-471d). Specifically, the internal space of the second header collecting pipe (470) is divided into three communication spaces (471b, 471 c, 471 d) corresponding respectively to the main heat exchange parts (451a-451c) of the upper heat exchange region (451), and a single communication space (471a) corresponding to the auxiliary heat exchange part (452a) of the lower heat exchange region (452). That is, in the internal space of the second header collecting pipe (470), the first communication space (471a) communicating with the flat tubes (58) of the auxiliary heat exchange part (452a), the second communication space (471b) communicating with the flat tubes (53) of the first main heat exchange part (451a), the third communication space (471c) communicating with the flat tubes (53) of the second main heat exchange part (451b), and the fourth communication space (471d) communicating with the flat tubes (53) of the third main heat exchange part (451c) are formed.

[0112] In the second header collecting pipe (470), a communication member (475) is provided. The communication member (475) includes a single distributor (476), a single main pipe (477), and three thin pipes (478a-478c). The main pipe (477) is, at one end thereof, connected to a lower end part of the distributor (476), and is, at the other end thereof, connected to the first communication space (471a) of the second header collecting pipe (470). The thin pipe (478a-478c) is, at one end thereof, connected to an upper end part of the distributor (476). In the distributor (476), the main pipe (477) and the thin pipes (478a-478c) communicate with each other. The thin pipe (478a-478c) communicates, at the other end thereof, with a corresponding one of the second to fourth communication spaces (471b-471d) of the second header collecting pipe (470).

[0113] Referring to FIG. 20, the thin pipe (478a-478c) opens at part of a corresponding one of the second to fourth communication spaces (471b-471d) close to a lower end thereof. That is, the thin pipe (478a) opens at part of the second communication space (471b) close to the lower end thereof, the thin pipe (478b) opens at part of the third communication space (471c) close to the lower end thereof, and the thin pipe (478c) opens at part of the fourth communication space (471d) close to the lower end thereof. Note that the length of the thin pipe (478a-478c) is independently set such that the difference in flow rate of refrigerant flowing into the main heat exchange parts (451a-451c) is reduced as much as possible. As described above, the communication member (475) of the second header collecting pipe (470) is connected so as to branch from the communication space (471a) into the second to fourth communication spaces (471b-471d) corresponding respectively to the main heat exchange parts (451a-451c). That is, in the second header collecting pipe (470), the communication space (471a) corresponding to the lower heat exchange region (452) and the communication space (471b-471d) corresponding to the upper heat exchange region (451) communicate with each other.

[0114] Referring to FIG. 19, in the outdoor heat exchanger (40), a liquid connection member (486) and a gas connection member (485) are provided. The liquid connection member (486) and the gas connection member (485) are attached to the first header collecting pipe (460). The liquid connection member (486) is formed of a single pipe having a relatively-large diameter. A pipe connecting between the outdoor heat exchanger (40) and an expansion valve (33) is connected to one end of the liquid connection member (486). The liquid connection member (486) opens, at the other end thereof, at part of the lower space (462) (communication space (462a)) close to a lower end thereof in the first header collecting pipe (460). The gas connection member (485) is formed of a single pipe having a relatively-large diameter. A pipe connecting between the outdoor heat exchanger (40) and a third port of a four-way valve (34) is connected to one end of the gas connection member (485). The gas connection member (485) opens, at the other end thereof, at part of the upper space (461) close to an upper end thereof in the first header collecting pipe (460).

[0115] According to the foregoing configuration, in the outdoor heat exchanger (40) of the present embodiment, refrigerant flows in a direction indicated by arrows illustrated in FIG. 19 in an air-cooling operation. In an air-heating operation, refrigerant flows in a direction opposite to the direction indicated by the arrows illustrated in FIG. 19.

<<Fifth Embodiment of the Invention>>

[0116] A fifth embodiment of the present disclosure will be described. The present embodiment is configured in such a manner that the configuration of the second header collecting pipe (470) of the outdoor heat exchanger (40) of the third embodiment is changed. The other configuration is similar to that of the third embodiment. In the present embodiment, only a configuration of a second header collecting pipe (470) of an outdoor heat exchanger (40) will be described with reference to FIGS. 21 and 22.

[0117] FIG. 21 is a front view illustrating the schematic configuration of the outdoor heat exchanger (40) of the fifth embodiment. Moreover, FIG. 22 is a partial cross-sectional view illustrating a front side of the outdoor heat exchanger (40) of the fifth embodiment. Referring to FIG. 22, an internal space of the second header collecting pipe (470) of the outdoor heat exchanger (40) is vertically divided into three communication spaces (471a-471c) by two partition plates (439). Specifically, in the internal space of the second header collecting pipe (470), the first communication space (471a), the second communication space (471b), and the third communication space (471c) are formed in this order from the right as viewed in FIG. 22. The first communication space (471a) communicates with flat tubes (53) of a third main heat exchange part (451c) and flat tubes (58) of a first auxiliary heat exchange part (452a). The second communication space (471b) communicates with flat tubes (53) of a second main heat exchange part (451b) and flat tubes (58) of a second auxiliary heat exchange part (452b). The third communication space (471c) communicates with flat tubes (53) of a first main heat exchange part (451a) and flat tubes (58) of a third auxiliary heat exchange part (452c). In the outdoor heat exchanger (40), the third main heat exchange part (451 c) and the first auxiliary heat exchange part (452a) are paired together, the second main heat exchange part (451b) and the second auxiliary heat exchange part (452b) are paired together, and the first main heat exchange part (451a) and the third auxiliary heat exchange part (452c) are paired together.

[0118] That is, in the second header collecting pipe (470) of the outdoor heat exchanger (40) of the present embodiment, the main heat exchange part (451 a-451 c) in an upper heat exchange region (451) is paired with a corresponding one of the auxiliary heat exchange parts (452a-452c) in a lower heat exchange region (452). The communication space (471a-471c) for a corresponding one of the pairs of heat exchange parts (451a-451c, 452a-452c) is formed such that the number (e.g., three) of communication spaces (471a-471c) is the same as the number of pairs. As described above, in the second header collecting pipe (470), the flat tubes (53, 58) of the pair of main heat exchange part (451a-451c) and auxiliary heat exchange part (452a-452c) directly communicate with each other in the internal space of the second header collecting pipe (470).

[0119] In the present embodiment, the width of the flat tube (58) provided in the auxiliary heat exchange part (452a-452c) is, as in the first embodiment, greater than that of the flat tube (53) provided in the main heat exchange part (451 a-451 c). Moreover, the number of flow paths per flat tube (58) provided in the auxiliary heat exchange part (452a-452c) is greater than the number of flow paths per flat tube (53) provided in the main heat exchange part (451a-451c).

[0120] According to the foregoing configuration, in the outdoor heat exchanger (40) of the present embodiment, refrigerant flows in a direction indicated by arrows illustrated in FIG. 21 in an air-cooling operation. In an air-heating operation, refrigerant flows in a direction opposite to the direction indicated by the arrows illustrated in FIG. 21.

<<Sixth Embodiment of the Invention>>

[0121] A sixth embodiment of the present disclosure will be described. The present embodiment is configured in such a manner that the configuration of the outdoor heat exchanger (40) of the third embodiment is changed. Differences in the outdoor heat exchanger (40) between the present embodiment and the third embodiment will be described with reference to FIGS. 23 and 24.

[0122] An internal space of a second header collecting pipe (470) of the present embodiment is, as in the third embodiment, horizontally divided into five communication spaces (471a-471e). In the second header collecting pipe (470) of the present embodiment, the first communication space (471a) and the fifth communication space (471e) are paired together, and the second communication space (471b) and the fourth communication space (471d) are paired together. Moreover, in the second header collecting pipe (470), a first communication pipe (472) connecting between the second communication space (471b) and the fourth communication space (471d) and a second communication pipe (473) connecting between the first communication space (471a) and the fifth communication space (471e) are provided. That is, in the outdoor heat exchanger (40) of the present embodiment, a first main heat exchange part (451a) and a third auxiliary heat exchange part (452c) are paired together, a second main heat exchange part (451b) and a second auxiliary heat exchange part (452b) are paired together, and a third main heat exchange part (451c) and a first auxiliary heat exchange part (452a) are paired together.

[0123] In the outdoor heat exchanger (40) of the present embodiment, a connection position of a gas connection member (485) in a first header collecting pipe (460) is changed. Specifically, the gas connection member (485) opens at a middle part of an upper space (461) (i.e., at the middle of the upper space (461) in the vertical direction) in the first header collecting pipe (460). Further, referring to FIG. 24, in the outdoor heat exchanger (40) of the present embodiment, the inner diameter B 1 of the first header collecting pipe (460) is greater than the inner diameter B2 of the second header collecting pipe (470). Such a configuration allows gas refrigerant flowing into the upper space (461) of the first header collecting pipe (460) through the gas connection member (485) to be equally distributed into the three main heat exchange parts (451a-451c).

[0124] In the outdoor heat exchanger (40) of the present embodiment, the inner diameters of the header collecting pipes (460, 470) may be equal to each other, and the gas connection member (485) may open at part of the upper space (461) close to an upper end thereof in the first header collecting pipe (460).

<<Seventh Embodiment of the Invention>>

[0125] FIG. 25 is a partial cross-sectional view of an outdoor heat exchanger (40) of a seventh embodiment. In the present embodiment, the width of a flat tube (53) of a main heat exchange part (50) and the width of a flat tube (58) of an auxiliary heat exchange part (55) are equal to each other. Moreover, as in the foregoing embodiments, the number of flat tubes (58) of the auxiliary heat exchange part (55) is less than the number of flat tubes (53) of the main heat exchange part (50). Further, the total cross-sectional area of refrigerant flow paths (49) per flat tube (58) provided in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of refrigerant flow paths (49) per flat tube (53) provided in the main heat exchange part (50). Although not shown in FIG. 25, the foregoing bare pipe (smooth inner pipe as illustrated in FIG. 7B) is, in the present embodiment, employed as the flat tube (53) of the main heat exchange part (50), and each of the refrigerant flow paths (49) has a circular cross section. On the other hand, in the flat tube (58) of the auxiliary heat exchange part (55), a plurality of grooves are formed in each of the refrigerant flow paths (49) (see FIG. 7A). In such a configuration, the flow velocity of refrigerant in the auxiliary heat exchange part (55) can be lowered. Thus, in the present embodiment, a pressure loss in the auxiliary heat exchange part (55) can be also reduced.

<<Eighth Embodiment of the Invention>>

[0126] In an outdoor heat exchanger (40) of an eighth embodiment, the width of a flat tube (53) of a main heat exchange part (50) and the width of a flat tube (58) of an auxiliary heat exchange part (55) are equal to each other. Moreover, the number of flat tubes (58) of the auxiliary heat exchange part (55) is less than the number of flat tubes (53) of the main heat exchange part (50).

[0127] Further, the total cross-sectional area of refrigerant flow paths (49) per flat tube (58) provided in the auxiliary heat exchange part (55) is greater than the total cross-sectional area of refrigerant flow paths (49) per flat tube (53) provided in the main heat exchange part (50). Specifically, the number of refrigerant flow paths (49) in the flat tube (53) of the main heat exchange part (50) is less than the number of refrigerant flow paths (49) in the flat tube (58) of the auxiliary heat exchange part (55). In such a configuration, the flow velocity of refrigerant in the auxiliary heat exchange part (55) can be lowered. Thus, in the present embodiment, a pressure loss in the auxiliary heat exchange part (55) can be also reduced. Note that each of the refrigerant flow paths (49) of the heat transfer pipe (53, 58) in the main heat exchange part (50) or the auxiliary heat exchange part (55) may be provided with or without grooves (see FIGS. 7A and 7B).

[0128] Note that, in each of the outdoor heat exchangers (40) of the second to eighth embodiments, various fins such as the fins (54, 59, 235, 236) described in the first embodiment and the variations thereof may be employed.

INDUSTRIAL APPLICABILITY

[0129] The present disclosure is useful as the heat exchanger including the flat tubes and the fins and configured to exchange heat between fluid flowing through the flat tube and air and as the air conditioner.

DESCRIPTION OF REFERENCE CHARACTERS

[0130] 

10

Air Conditioner

40

Outdoor Heat Exchanger (Heat Exchanger)

49

Refrigerant Flow Path (Flow Path)

50

Main Heat Exchange Part

51, 56

First Header Collecting Pipe

52, 57

Second Header Collecting Pipe

53

Flat tube

54, 59

Fin

55

Auxiliary Heat Exchange Part

58

Flat tube

Claims

1. A heat exchanger including
a plurality of flat tubes (53, 58) arranged in a vertical direction such that side surfaces thereof face each other and each formed with a plurality of flow paths (49) of fluid, and
a plurality of fins (54, 59) configured to divide part between adjacent ones of the flat tubes (53, 58) into a plurality of air passages through each of which air flows, comprising:

a first header collecting pipe (51, 56); and

a second header collecting pipe (52, 57),

wherein each flat tube (53, 58) is, at one end thereof, connected to the first header collecting pipe (51, 56), and is, at the other end thereof, connected to the second header collecting pipe (52, 57),

some of the flat tubes (53) form a main heat exchange part (50), and the other flat tubes (58) form an auxiliary heat exchange part (55),

the flat tubes (58) forming the auxiliary heat exchange part (55) are fewer than the flat tubes (53) forming the main heat exchange part (50),

a total cross-sectional area of the flow paths (49) per flat tube (58) in the auxiliary heat exchange part (55) is greater than a total cross-sectional area of the flow paths (49) per flat tube (53) in the main heat exchange part (50), and

if the heat exchanger serves as a condenser, refrigerant is condensed in the main heat exchange part (50), and the refrigerant is sub-cooled in the auxiliary heat exchange part (55).

2. The heat exchanger of claim 1, wherein
a width (W2) of each flat tube (58) of the auxiliary heat exchange part (55) is greater than a width (W1) of each flat tube (53) of the main heat exchange part (50), and
the flow paths per flat tube (58) in the auxiliary heat exchange part (55) is more than the flow paths per flat tube (53) in the main heat exchange part (50).

3. The heat exchanger of claim 1 or 2, wherein
each flow path (49) is formed with a plurality of grooves in a corresponding one of the flat tubes (53) of the main heat exchange part (50), and
each flat tube (58) of the auxiliary heat exchange part (55) is a bare pipe.

4. The heat exchanger of any one of claims 1-3, wherein
each fin (236) is formed in such a plate shape that a plurality of cut parts (245) into each of which a corresponding one of the flat tubes (53, 58) is inserted are provided,
the fins (236) are arranged at predetermined intervals in an extension direction of the flat tubes (53, 58),
each flat tube (53, 58) is sandwiched between peripheral edge parts of a corresponding one of the cut parts (245) of the fins (236), and
in each fin (236), part between adjacent ones of the cut parts (245) arranged in the vertical direction forms a heat transfer part (237).

5. The heat exchanger of claim 4, wherein
an end of each flat tube (53, 58) in a width direction thereof is aligned with an end of a corresponding one of the cut parts (245) on an open side thereof.

6. An air conditioner, comprising:

a refrigerant circuit (20) provided with the heat exchanger (40) of any one of claims 1-5,

wherein refrigerant circulates to perform a refrigeration cycle in the refrigerant circuit (20).

Drawing