WO2020178977A1

WO2020178977A1 - Heat exchanger, heat exchanger unit, and refrigeration cycle device

Info

Publication number: WO2020178977A1
Application number: PCT/JP2019/008580
Authority: WO
Inventors: 中村　伸; 前田　剛志; 暁八柳; 森田　敦
Original assignee: 三菱電機株式会社
Priority date: 2019-03-05
Filing date: 2019-03-05
Publication date: 2020-09-10
Also published as: JPWO2020178977A1; JP7118238B2

Abstract

The purpose of the present invention is to provide: a heat exchanger in which water is not easily stayed in the gaps between flat tubes and drainage performance is improved; a heat exchanger unit; and a refrigeration cycle device. The present invention is provided with a first flat tube and a second flat tube, the tube axes of which are arranged in parallel, wherein the first flat tube has a first side surface facing the second flat tube, and the second flat tube has a second side surface facing the first flat tube. The first side surface of the first flat tube is arranged facing the second side surface of the second flat tube, and a hydrophilic region which is at least a portion of the first side surface has higher hydrophilicity than the second side surface.

Description

Heat exchanger, heat exchanger unit, and refrigeration cycle device

The present invention relates to a heat exchanger, a heat exchanger unit including a heat exchanger, and a refrigeration cycle device, and more particularly to the structure of fins attached to a flat tube.

Conventionally, heat exchangers that circulate a refrigerant inside and evaporate or condense the refrigerant to exchange heat with a fluid such as air have been widely used in various fields such as air conditioners and refrigerators. Although it is a heat exchanger that plays an active role in various applications such as cooling heat-generating equipment and heating to working fluids, improvement in heat exchange performance and compactness is always required in all fields, and it is necessary to achieve both of these at the same time. It goes without saying that it has an advantage for the device itself on which the vessel is mounted.

Currently, there is a fin-and-tube heat exchanger as one of the typical heat exchangers. This fin-and-tube heat exchanger is manufactured by passing a plurality of tubes through a plurality of thin plate-shaped fins in a direction perpendicular to the fin surface, expanding these tubes, and attaching the fins to the tubes. The fin-and-tube heat exchanger is characterized by flowing a refrigerant inside the pipe and performing heat exchange with air by using a fin with a large heat transfer area that closely adheres to the outer wall of the pipe as a heat transfer medium. Various improvements have been made so far with the aim of improving. For example, in order to increase the heat transfer area, thin the fins to increase the number of fins, or improve the fins by forming slits on the fin surface. Similarly, in order to increase the heat transfer area, make the inner wall of the pipe uneven. Improvements have been made to such tubes.

On the other hand, in order to pursue further improvement of heat exchange performance and compactness, it is difficult to expect a great effect only by accumulating partial improvements within the category of fin-and-tube heat exchangers. There is. Against this background, many studies have been made on new forms of heat exchangers that replace conventional fin-and-tube heat exchangers. Among them, finless heat exchangers, which are heat exchangers that increase the heat transfer area by arranging a large number of tubes densely and do not use fins that connect a large number of tubes, are attracting attention. This finless heat exchanger has various forms depending on the application, from those in which circular pipes are regularly arranged to those in which pipes having a rectangular, elliptical, or streamline cross section are irregularly arranged. Things have been devised.

ㆍIn the finless heat exchanger, in terms of heat exchange performance, the heat exchange performance may be significantly reduced due to the elimination of fins. For example, a fin-and-tube heat exchanger having a pipe diameter of about 7 mm, a pitch between fins of about 1 mm, and a wind velocity of air sent by a fan of about 1 m/s, such as an indoor heat exchanger of a home air conditioner. If you try to change to a finless heat exchanger that uses a flat tube without changing the heat exchanger size and fan input, reduce the minor axis dimension of the minor axis of the cross section of the flat tube to about 2 to 3 mm, Even if the arrangement pitch of the flat tubes is made small, the heat transfer area is insufficient, and the heat exchange performance is significantly reduced.

Therefore, in Patent Document 1, in order to provide a heat exchanger for an air conditioner capable of improving heat exchange performance while ensuring compactness without causing an increase in pressure loss, fin and tube heat exchange is performed. The minor axis A, which is the minor axis dimension of the cross section of the tube of the vessel, is formed in the range of 0.31 to 1.40 mm, and the minor axis A and the pitch B of each flat tube are within a certain numerical range. It has been proposed to arrange each flat tube as described above.

Japanese Patent No. 3264525

However, in the fin-and-tube heat exchanger as shown in Patent Document 1, when it is operated as an evaporator, the condensed water generated by condensing the moisture in the air is generated between the adjacent fins. It may stay across. When the pitch B of each flat tube of the finless heat exchanger is arranged at the same degree as the fin pitch of the conventional fin-and-tube type heat exchanger as shown in Patent Document 1, the finless heat exchanger also has the above-mentioned structure. The phenomenon of accumulated condensed water may occur. In such a finless heat exchanger, the heat transfer performance can be ensured because the pitch B of each flat tube is small, but dew condensation water is retained across adjacent flat tubes. As a result, the finless heat exchanger has a problem that the heat transfer performance and the ventilation performance are impaired when it is operated as an evaporator.

The present invention is for solving the above problems, and even in a finless heat exchanger in which the distance between the flat tubes is narrow, it is difficult for water to stay in the clearance between the flat tubes and the heat with improved drainage is provided. An object is to obtain an exchanger, a heat exchanger unit, and a refrigeration cycle device.

A heat exchanger according to the present invention includes a first flat tube and a second flat tube whose tube axes are arranged in parallel, and the first flat tube is a first flat tube that faces the second flat tube. And the second flat tube has a second side surface facing the first flat tube, and the hydrophilic region that is at least a part of the first side surface has the second side surface. More hydrophilic than.

The heat exchanger unit according to the present invention includes the above heat exchanger.

The refrigeration cycle apparatus according to the present invention includes the heat exchanger unit described above.

According to the present invention, since the two opposite side surfaces of the first flat tube and the second flat tube are configured to have different hydrophilicity, when the condensed water straddles the two side surfaces. It moves from the side with low hydrophilicity to the side with high hydrophilicity. By moving the dew condensation water, it is possible to prevent the dew condensation water from accumulating between the two flat tubes, and the drainage performance is improved. As a result, deterioration of ventilation performance and heat transfer performance can be suppressed even in a heat exchanger in which the intervals between the flat tubes are narrow.

It is a perspective view which shows the heat exchanger unit which concerns on Embodiment 1. FIG. It is a front view which shows the heat exchanger which concerns on Embodiment 1. FIG. It is explanatory drawing of the refrigeration cycle apparatus 1 to which the heat exchanger which concerns on Embodiment 1 is applied. It is explanatory drawing of the cross-sectional structure of the heat exchanger of FIG. FIG. 5 is a diagram showing hydrophilicity of surfaces of a plurality of flat tubes of the heat exchanger according to the first embodiment. It is explanatory drawing in the case of water droplets adhering to the surface of the plurality of flat tubes of the heat exchanger of the first embodiment. FIG. 5 is a schematic diagram of a heat exchanger that is a comparative example of the heat exchanger of the first embodiment. FIG. 5 is a schematic diagram of a heat exchanger that is a comparative example of the heat exchanger of the first embodiment. FIG. 5 is a schematic diagram showing the behavior of water in the outdoor heat exchanger according to the first embodiment. FIG. 5 is a schematic diagram showing the behavior of water in the outdoor heat exchanger according to the first embodiment. FIG. 5 is a schematic diagram showing the behavior of water in the outdoor heat exchanger according to the first embodiment. FIG. 5 is an explanatory diagram in the case where water droplets adhere to the surfaces of a plurality of flat tubes of the heat exchanger of the first embodiment. It is explanatory drawing of the cross-section of the heat exchanger which is a modification of the heat exchanger which concerns on Embodiment 1. It is explanatory drawing of the cross-section of the heat exchanger which concerns on Embodiment 2. It is a figure which shows the hydrophilicity property of the surface of the plurality of flat tubes of the heat exchanger which concerns on Embodiment 2. FIG. It is a figure which shows the hydrophilicity property of the surface of the plurality of flat tubes of the heat exchanger which is the modification of the heat exchanger which concerns on Embodiment 2. FIG. It is a figure which shows the hydrophilicity property of the surface of the plurality of flat tubes of the heat exchanger according to the third embodiment. It is a figure which shows the hydrophilicity property of the surface of the plurality of flat tubes of the heat exchanger which concerns on Embodiment 4. FIG. It is a figure which shows the hydrophilicity property of the surface of the plurality of flat tubes of the heat exchanger according to the fifth embodiment. It is explanatory drawing of the cross-sectional structure of the heat exchanger which concerns on Embodiment 6. It is explanatory drawing of the cross-sectional structure of the heat exchanger which is the modification of the heat exchanger which concerns on Embodiment 6.

The embodiments of the heat exchanger, the heat exchanger unit, and the refrigeration cycle device will be described below. The drawings are merely examples, and the present invention is not limited thereto. In addition, those having the same reference numerals in the respective figures are the same or equivalent thereof, which are common to the entire text of the specification. Furthermore, in the following drawings, the size relationship of each component may be different from the actual one.

Embodiment 1.
FIG. 1 is a perspective view showing a heat exchanger unit 101 according to the first embodiment. FIG. 2 is a front view showing the heat exchanger 100 according to the first embodiment. FIG. 3 is an explanatory diagram of the refrigeration cycle device 1 to which the heat exchanger 100 according to the first embodiment is applied. The heat exchanger unit 101 shown in FIG. 1 is an example, and corresponds to the outdoor unit 8 of the air conditioner here. The heat exchanger 100 shown in FIG. 2 is mounted inside the heat exchanger unit 101 of FIG. 1, and schematically shows the structure as viewed from the front. The heat exchanger 100 is mounted on the refrigeration cycle device 1 such as an air conditioner or a refrigerator, and can be used as the outdoor heat exchanger 5 or the indoor heat exchanger 7 in the refrigeration cycle device 1. As shown in FIG. 3, in the refrigeration cycle apparatus 1, the compressor 3, the four-way valve 4, the outdoor heat exchanger 5, the expansion device 6, and the indoor heat exchanger 7 are connected by a refrigerant pipe 90 to form a refrigerant circuit. It was done. For example, when the refrigeration cycle device 1 is an air conditioner, the refrigerant flows through the refrigerant pipe 90, and the four-way valve 4 switches the refrigerant flow to perform heating operation, freezing operation, or defrosting operation. It can be switched.

The outdoor heat exchanger 5 mounted on the outdoor unit 8 and the indoor heat exchanger 7 mounted on the indoor unit 9 are provided with the blower 2 in the vicinity. In the outdoor unit 8, the blower 2 sends outside air to the outdoor heat exchanger 5. The outdoor heat exchanger 5 exchanges heat between the outside air and the refrigerant. Further, in the indoor unit 9, the blower 2 sends indoor air to the indoor heat exchanger 7. The indoor heat exchanger 7 exchanges heat between the indoor air and the refrigerant to harmonize the temperature of the indoor air. Further, the heat exchanger 100 according to Embodiment 1 can be used as the outdoor heat exchanger 5 mounted on the outdoor unit 8 and the indoor heat exchanger 7 mounted on the indoor unit 9 in the refrigeration cycle apparatus 1, Functions as a condenser or evaporator. Devices such as the outdoor unit 8 and the indoor unit 9 on which the heat exchanger 100 is mounted are particularly referred to as a heat exchanger unit 101. The heat exchanger unit 101 shown in FIG. 1 is an example of an outdoor unit 8 on which the heat exchanger 100 is mounted. The arrow shown in FIG. 1 indicates the flow direction of the air flow. The heat exchanger unit 101 takes in outside air into the housing from the back side, performs heat exchange between the outside air and the refrigerant in the heat exchanger 100, and blows out the heat-exchanged air from the front side.

The heat exchanger 100 shown in FIG. 2 includes a plurality of flat tubes 20. The plurality of flat tubes 20 are juxtaposed in the X direction, and one of the plurality of flat tubes 20 adjacent to each other is referred to as a first flat tube 20a, and the other is referred to as a second flat tube 20b. The plurality of flat tubes 20 are arranged with their tube axes along the Z direction, and are arranged in parallel along the X direction. In the first embodiment, the Z-direction reverse direction matches the gravity direction, but the heat exchanger 100 may be arranged with the Z-axis tilted in the gravity direction.

The plurality of flat tubes 20 are connected to the lower end header 80 at the lower end in the Z direction and are connected to the upper end header 81 at the upper end in the Z direction. The lower end header 80 and the upper end header 81 are connected to the refrigerant pipe 90 of the refrigeration cycle apparatus 1, and the refrigerant flowing through the refrigerant circuit flows into one of the lower end header 80 and the upper end header 81 to connect the plurality of flat tubes 20. It passes through and flows out from the other side to the refrigerant pipe 90. The plurality of flat tubes 20 are so-called finless heat exchangers in which fins connecting between the plurality of flat tubes 20 are not provided in addition to the lower end header 80 and the upper end header 81. Furthermore, the plurality of adjacent flat tubes 20 are not provided with a member that connects the first side surface 25a and the second side surface 25b that face each other.

4 is an explanatory diagram of a cross-sectional structure of the heat exchanger 100 of FIG. FIG. 4 shows a cross section perpendicular to the tube axes of the plurality of flat tubes 20, and is an explanatory view of the structure of the cross section corresponding to the AA cross section in FIG. In addition, in FIG. 4, a part of the plurality of flat tubes 20 is shown. The plurality of flat tubes 20 are formed in a flat shape having a cross section perpendicular to the tube axis having a long axis and a short axis. The plurality of flat tubes 20 are arranged with their major axes oriented in the Y direction and their minor axes oriented in the X direction. That is, the Y direction is the long axis direction of the flat tube 20, and the X direction is the short axis direction of the flat tube 20. The flow direction of the air flow passing through the heat exchanger 100 substantially coincides with the Y direction. Further, the plurality of flat pipes 20 have a first end portion 21 which is an end portion located on the windward side in the flow direction of the air flow and a second end portion 22 which is an end portion located on the leeward side.

The plurality of flat tubes 20 include a first flat tube 20a and a second flat tube 20b arranged adjacent to the first flat tube 20a. Here, in the first flat tube 20a, the side surface facing the X direction is referred to as the first side surface 25a, and the side surface facing the opposite direction in the X direction is referred to as the second side surface 25b. Further, in the second flat tube 20b, the side surface facing the X direction is referred to as the first side surface 25a, and the side surface facing the opposite direction in the X direction is referred to as the second side surface 25b. That is, the first flat tube 20a and the second flat tube 20b have a first side surface 25a that is a side surface along the major axis direction and a second side surface 25b that is located on the opposite side of the first side surface 25a. Has. The first flat tube 20a and the second flat tube 20b have a first side surface 25a that is a side surface facing the short axis direction and a second side surface 25b that is located on the opposite side of the first side surface 25a. .. The first flat tube 20a and the second flat tube 20b are arranged adjacent to each other, and the first side surface 25a and the second side surface 25b are arranged to face each other. Note that the plurality of flat tubes 20 may be configured by only two types of the first flat tube 20a and the second flat tube 20b, or may include other flat tubes having different configurations.

The plurality of flat tubes 20 are each made of a metal material having thermal conductivity. As a material forming each of the plurality of flat tubes 20, for example, aluminum, an aluminum alloy, copper, or a copper alloy is used. Each of the plurality of flat tubes 20 is manufactured by extruding a heated material from a hole in a die to form a plurality of refrigerant flow paths 24 shown in FIG. Note that each of the plurality of flat tubes 20 may be manufactured by a drawing process in which a material is drawn out from a hole of a die and a cross section shown in FIG. 4 is formed. The method of manufacturing each of the plurality of flat tubes 20 can be appropriately selected according to the cross-sectional shape.

FIG. 5 is a diagram showing the hydrophilicity of the surfaces of the plurality of flat tubes 20 of the heat exchanger 100 of the first embodiment. FIG. 5 shows the same cross section as that of FIG. 4, and schematically represents regions having different hydrophilicity on the surfaces of the plurality of flat tubes 20 in different patterns. The plurality of flat tubes 20 are configured by arranging a first flat tube 20a and a second flat tube 20b adjacent to each other. The first flat tube 20a and the second flat tube 20b differ from each other in hydrophilicity on two side surfaces along the major axis direction. In FIG. 5, the first side surface 25a has high hydrophilicity and the second side surface 25b has low hydrophilicity. In the first embodiment, the first flat tube 20a and the second flat tube 20b have the same hydrophilicity throughout the first side surface 25a and the second side surface 25b, respectively. It is not limited to this. The first side surface 25a and the second side surface 25b may have regions having different hydrophilicities. However, the first side surface 25a and the second side surface 25b are configured such that the surfaces facing each other differ in hydrophilicity at least in part.

FIG. 6 is an explanatory view when water droplets adhere to the surfaces of the plurality of flat tubes 20 of the heat exchanger 100 of the first embodiment. FIG. 6 shows an example of a state of water droplets attached to the first side surface 25a or the second side surface 25b of the plurality of flat tubes 20. When water droplets such as condensed water adhere to the surfaces of the plurality of flat tubes 20, the shape of the water droplets changes depending on the degree of hydrophilicity of the surfaces. The contact angle θ is generally used as an index indicating the affinity between the surface of an object and water. The contact angle θ is an angle formed by a water drop dropped on the surface of the object and the surface. When the hydrophilicity of the surface of the object is high, the contact angle θ becomes small, and when the hydrophilicity of the surface of the object is low, the contact angle θ becomes large. When the hydrophilicity is high, the water droplets tend to spread thinly on the surfaces of the plurality of flat tubes 20, and when the hydrophilicity is low, the water droplets are rounded by the surface tension. When the hydrophilicity is low, it is also called high water repellency. Generally, the contact angle θ is used as an index showing the affinity between the surface of a solid and water. The contact angle θ is defined as the angle formed by the contact surface between the surface of the solid and the water droplet when the water droplet is dropped on the surface of the solid.

When water is dripped on the surface of the member, the water becomes round with its own surface tension γw. When the surface tension of the solid is γs and the interfacial tension between the surface of the solid and the surface of water is γsw, the relationship of γs=γw·cos θ+γsw is established between the water dropped on the surface of the solid and the surface. In other words, the surface tension γs of the solid is balanced with the surface direction component of the surface tension γw of water and the resultant force of the interfacial tension γsw between the surface of the solid and water, and at this time, the angle formed by the surface of water and the surface of the solid is in contact. The angle is θ.

FIG. 7 is a schematic diagram of a heat exchanger 1100 which is a comparative example of the heat exchanger 100 of the first embodiment. FIG. 7 shows a part of the heat exchanger 1100, and schematically shows a state where water droplets are attached to the first side surface 1025a and the second side surface 1025b of the plurality of flat tubes 1020. The plurality of flat tubes 1020 are configured by arranging a first flat tube 1020a and a second flat tube 1020b adjacent to each other. The plurality of flat tubes 1020 of the heat exchanger 1100 of the comparative example have the same hydrophilic property on the first side surface 1025a and the second side surface 1025b, and are in a state of high water repellency. That is, the surfaces of the plurality of flat tubes 1020 have a large contact angle θ, and in particular, the contact angle θ ≧ 90 °. Further, in the heat exchanger 1100 of the comparative example, the relationship between the contact angle θ1 of the first side surface 1025a and the contact angle θ2 of the second side surface 1025b is θ1 = θ2.

When water adheres to the surfaces of a plurality of flat tubes 1020 having low hydrophilicity, that is, high water repellency as in the heat exchanger 1100 of the comparative example, water droplets are applied to either the first side surface 1025a or the second side surface 1025b. Easy to stay as Further, particularly when water droplets attached to both

side surfaces

1025a, 1025b come into contact with each other, a similar force acts on the water droplets from the

side surfaces

1025a, 1025b of the two facing flat tubes, so that the water droplets may be applied to one of the

side surfaces

1025a, 1025b. There is no bias. Here, when there is not enough water to overcome the force received from the surfaces of both

side surfaces

1025a and 1025b, the water is bridged between the first side surface 1025a and the second side surface 1025b. There is a problem that the water is retained as it is without flowing down, and water easily accumulates. The retention of water between the plurality of flat tubes 1020 increases the resistance to the flow of air passing between the plurality of flat tubes 20. Then, the load of the blower 2 is increased, and the flow rate of air passing through the heat exchanger 1100 is reduced. Further, the water droplets in the gaps between the plurality of flat tubes 1020 become thermal resistance to heat transfer between the air flowing through the gaps and the refrigerant flowing in the plurality of flat tubes 1020, and the heat exchange efficiency is reduced.

FIG. 8 is a schematic diagram of a heat exchanger 2100 which is a comparative example of the heat exchanger 100 of the first embodiment. FIG. 8 shows a part of the heat exchanger 2100, and schematically shows a state in which water droplets are attached to the first side surface 2025a and the second side surface 2025b of the plurality of flat tubes 2020. The plurality of flat tubes 2020 are configured by arranging a first flat tube 2020a and a second flat tube 2020b adjacent to each other. The plurality of flat tubes 2020 of the heat exchanger 2100 of the comparative example have the same hydrophilic property as the first side surface 2025a and the second side surface 2025b, and are in a highly hydrophilic state. That is, the surfaces of the plurality of flat tubes 2020 have a small contact angle θ, and in particular, the contact angle θ <90 °. Further, in the heat exchanger 1100 of the comparative example, the relationship between the contact angle θ1 of the first side surface 2025a and the contact angle θ2 of the second side surface 2025b is θ1 = θ2.

When water adheres to the surfaces of a plurality of flat tubes 2020 that are highly hydrophilic, the water tends to stay in a film form on the surface. The water adhering to the first side surface 2025a or the second side surface 2025b spreads more thinly than the water droplets staying on the highly water-

repellent side surfaces

1025a, 1025b, and therefore does not bridge the gaps between the plurality of flat tubes 2020, The ventilation resistance passing through the heat exchanger 2100 is unlikely to increase. However, the water adheres so as to partially cover the surface of the first side surface 2025a or the second side surface 2025b, and heat resistance to heat transfer between the air flowing through the gap and the refrigerant flowing inside the plurality of flat tubes 2020. And the heat exchange efficiency decreases.

The

heat exchangers

1100 and 2100 according to the comparative example need to be operated with frost formation and defrosting when used under conditions where the outside air temperature is low. When the

heat exchangers

1100 and 2100 are operated in a frosted state, water attached to the plurality of flat tubes 1020 and 2020 freezes. Therefore, when defrosting the

heat exchangers

1100 and 2100, it is necessary to melt the frozen water, and the amount of heat that is input to the

heat exchangers

1100 and 2100 during defrosting operation increases. It will increase. The air conditioning apparatus during the defrosting operation generally stops the heating operation. Therefore, in the

heat exchangers

1100 and 2100 according to the comparative example, the frequency of the defrosting operation increases, and thus the comfort of the room decreases and the operation efficiency of the refrigeration cycle apparatus 1 decreases when heating the room. ..

In the heat exchanger 100 according to the first embodiment, when the contact angle of at least the first side surface 25a is θ1 and the contact angle of the second side surface 25b is θ2, the relationship of θ1<θ2 is satisfied. That is, it can be said that the first side surface 25a having a surface with a small contact angle θ1 is more hydrophilic than the second side surface 25b. Further, it can be said that the second side surface 25b having the surface with the large contact angle θ2 has higher water repellency than the first side surface 25a.

9 to 11 are schematic diagrams showing the behavior of water in the outdoor heat exchanger 10 according to the first embodiment. 9 to 11 are views as seen from the upstream side of the air flow passing through the heat exchanger 100. In the heat exchanger 100 of the first embodiment, the contact angle θ1 of the first side surface 25a and the contact angle θ2 of the second side surface 25b satisfy the relationship of θ1 <θ2. As shown in FIGS. 9 to 11, when the contact angles θ of the side surfaces 25a and 25b forming the gap of the plurality of flat tubes 20 are different, the

water droplets

70a and 70b attached to the two surfaces forming the gap contact each other. Then, the water droplet 70b staying on the second side surface 25b having high water repellency easily moves to the side of the first side surface 25a having high hydrophilicity. Therefore, the amount of water adhering to the first side surface 25a increases, and the downward force applied to the water droplet 70 due to the gravity G also increases. If the water is completely transferred from the second side surface 25b to the first side surface 25a, the weight is further increased.

On the other hand, as shown in FIG. 7, in the heat exchanger 1100 of the comparative example, the water droplet 1070 adheres to both of the two

side surfaces

1025a, 1025b forming the gap, so that the two

side surfaces

1025a, 1025b It receives the interfacial tension γsw between the solid and water, the surface tension γs of the solid, and the surface tension γw of water. Here, when the gravity G applied to the water droplet 1070 exceeds the resultant force of the forces received from the

side surfaces

1025a and 1025b, the water falls. However, in the heat exchanger 100 according to the first embodiment and the

heat exchangers

1100 and 2100 according to the comparative example, the first

flat tubes

20a, 1020a, 2020a and the second

flat tubes

20b, 1020b, 2020b The intervals are narrow. Therefore, the downward force exerted on the

water droplets

70, 1070, and 2070 by the gravity G is small. Therefore, when the

water droplets

70, 1070, and 2070 receive a strong force from the first

flat tubes

20a, 1020a, and 2020a and the second

flat tubes

20b, 1020b, and 2020b, the

water droplets

70, 1070, and 2070 have a plurality of flattened shapes. It becomes easy to stay between the pipes 20, 1020 and 2020. Therefore, in the heat exchanger 1100 of the comparative example shown in FIG. 7, the water droplet 1070 receives a force from both of the two

side surfaces

1025a and 1025b forming the gap, and therefore tends to stay in the gap.

In the heat exchanger 100 according to the first embodiment, as shown in FIG. 11, the upward force exerted on the water droplet 70 acts only from the first side surface 25a having high hydrophilicity. Therefore, the amount of water droplets 70 retained between the plurality of flat tubes 20 of the heat exchanger 100 is smaller than that of the heat exchanger 1100 of the comparative example shown in FIG. 7. Moreover, in the heat exchanger 100 according to Embodiment 1, the amount of the water droplet 70 on the second side surface 25b that moves to the first side surface 25a and adheres to the highly hydrophilic first side surface 25a. Will increase. Therefore, the downward force applied to the water droplet 70 becomes stronger, and the water droplet 2070 that is present in the gap between the plurality of flat tubes 2020 of the heat exchanger 2100 of the comparative example is more likely to move downward. Therefore, the amount of water droplets 70 retained between the plurality of flat tubes 20 of the heat exchanger 100 is smaller than that of the heat exchanger 2100 of the comparative example shown in FIG.

As described above, the heat exchanger 100 according to the first embodiment includes the first flat tubes 20a and the second flat tubes 20b that are arranged in parallel with the tube axis in the vertical direction. And the 1st flat tube 20a and the 2nd flat tube 20b are located in the 1st side surface 25a which is a side surface along the long axis direction in the cross section perpendicular|vertical to a tube axis, and the opposite side of the 1st side surface 25a. And a second side surface 25b. The first side surface 25a of the first flat tube 20a is arranged so as to face the second side surface 25b of the second flat tube 20b. The hydrophilic region, which is at least a part of the first side surface 25a, is more hydrophilic than the second side surface 25b. With such a configuration, the water droplets 70 such as dew condensation water in the gaps between the plurality of flat tubes 20 easily move from the second side surface 25b to the opposing first side surface 25a, so that the plurality of flat tubes 20 have the same shape. The amount of water that accumulates between them is reduced. Therefore, the heat exchanger 100 according to the first embodiment has improved drainage performance, reduced ventilation resistance and heat resistance between air and the refrigerant, and thus eliminated

heat exchangers

1100 and 2100 of the comparative example. The frost operation time can be reduced. Specifically, the contact angle θ1 of the hydrophilic region of the first side surface 25a is smaller than the contact angle θ2 of the region of the second side surface 25b facing the hydrophilic region.

Desirably, the contact angle θ1 of the hydrophilic area of the first side surface 25a is lower than 90°, and the contact angle θ2 of the area of the second side surface 25b facing the hydrophilic area is 90° or more. This is because one of the surfaces facing each other has low hydrophilicity, that is, high water repellency, so that the water droplet 70b on the second side surface 25b easily moves to the first side surface 25a having higher hydrophilicity.

FIG. 12 is an explanatory view when water droplets adhere to the surfaces of the plurality of flat tubes 20 of the heat exchanger 100 of the first embodiment. In FIG. 12, the surfaces of the plurality of flat tubes 20 are inclined. When a water droplet on the surface of an object is gradually inclined from a horizontal state, the inclination angle α at which the water droplet starts to slide is called the falling angle. It can be said that the surface of an object having a small falling angle has weak adhesion to water droplets and water droplets are easily removed from the surface of the object. Therefore, on the surface of the object to which the same amount of water is attached, the smaller the falling angle, the higher the water detachability. Therefore, in the first embodiment, the second side surface 25b may be configured so that the fall angle is smaller than that of the hydrophilic region of the first side surface 25a. In other words, the fall angle of the hydrophilic region of the first side surface 25a may be larger than the fall angle of the region of the second side surface 25b facing the hydrophilic region. This makes it easier for water to concentrate from the second side surface 25b, which has high water releasability, to the first side surface 25a, which has relatively low water releasability. When water is concentrated on the first side surface 25a, the water spreads on the first side surface 25a, and the water adhering to the plurality of flat pipes 20 easily flows down due to the weight of the water itself. As a result, the heat exchanger 100 according to Embodiment 1 can further reduce the amount of water retained between the plurality of flat tubes 20.

FIG. 13 is an explanatory diagram of a cross-sectional structure of a heat exchanger 100A which is a modified example of the heat exchanger 100 according to the first embodiment. As shown in FIG. 13, the cross-sectional shapes of the plurality of flat tubes 120 are bent at the central portion in a cross section perpendicular to the tube axis, and the two linearly extending portions are formed at a predetermined angle. It has a shape that is held and connected. That is, the plurality of flat tubes 120 do not have a shape that linearly extends in the major axis direction in a cross section perpendicular to the tube axis, but have a shape that is bent on the way from one end 21 to the other end 22. There is. The long axis direction of the plurality of flat tubes 120 means a direction in which a straight line connecting the

end portions

21 and 22 extends. The plurality of flat tubes 120 is not limited to the shape shown in FIG. 13. For example, the shape may be such that a plurality of points are bent in the middle of the plurality of flat tubes 120, and the bending angle can be appropriately set.

Embodiment 2.
The heat exchanger 200 according to the second embodiment differs from the heat exchanger 100 according to the first embodiment in the structure of the plurality of flat tubes 20. The second embodiment will be described focusing on the changes from the first embodiment.

FIG. 14 is an explanatory diagram of a cross-sectional structure of the heat exchanger 200 according to the second embodiment. FIG. 14 shows a cross section perpendicular to the tube axes of the plurality of flat tubes 20. Each of the plurality of flat pipes 20 extends in the Y direction from the refrigerant flow section 50 provided with a plurality of refrigerant flow paths 24 through which the refrigerant flows, and the end portion 21 of the refrigerant flow section 50 in the long axis direction. The fin portion 51 is provided. The fin portion 51 is a plate-shaped portion that protrudes from the end portion 21 in the Y direction and is installed along the pipe axes of the plurality of flat pipes 20. In the second embodiment, the fin portion 51 extends parallel to the long axis direction of the coolant circulation portion 50, that is, the Y direction, but the present invention is not limited to this configuration. For example, the fin portion 51 may extend from the end portion 21 at a predetermined angle with respect to the Y direction.

FIG. 15 is a diagram showing hydrophilicity of the surfaces of the plurality of flat tubes 20 of the heat exchanger 200 according to the second embodiment. The 1st flat tube 20a and the 2nd flat tube 20b which comprise the some flat tube 20 are equipped with the 1st side surface 25a and the 2nd side surface 25b, respectively. The first side surface 25a of the first flat tube 20a and the second side surface 25b of the second flat tube 20b do not have the same hydrophilicity in the entire area. In the first side surface 25a, the entire surface of the coolant circulation portion 50 and the surface of the fin portion 51 are highly hydrophilic regions. The second side surface 25b is configured such that the surface of the coolant circulation portion 50 is less hydrophilic than the first side surface 25a, and the fin portion 51 is a highly hydrophilic region like the first side surface 25a. It has become. With this configuration, it is possible to suppress the retention of water droplets in the gaps between the refrigerant flow portions 50 of the plurality of flat tubes 20 having a small gap.

In the heat exchanger 200, since the gap between the portions where the fin portions 51 face each other is relatively wide, the fin portions 51 may have a large influence on the ventilation resistance even if the fin portions 51 have high hydrophilicity or low hydrophilicity. Absent. However, as shown in FIG. 15, by making the fin portion 51 a highly hydrophilic region, water droplets move from the fin portion 51 located on the upwind side to the low hydrophilic refrigerant circulating portion 50 located on the leeward side. Hard to do. Therefore, it is possible to suppress water droplets from accumulating in the gap between the refrigerant circulation portions 50 having a small gap.

FIG. 16 is a diagram showing the hydrophilicity of the surfaces of the plurality of flat tubes 20 of the heat exchanger 200a, which is a modification of the heat exchanger 200 according to the second embodiment. As shown in FIG. 16, the fin portions 51 of the plurality of flat tubes 20 also have a high hydrophilicity on the first side surface 25a and a low hydrophilicity on the second side surface 25b, similarly to the refrigerant circulating portion 50. Is also good. With this configuration, the plurality of flat tubes 20 of the heat exchanger 200 are the same as those in the first embodiment when the difference in thickness between the refrigerant flow section 50 and the fin section 51 is small or the same thickness. In addition, the retention of water drops can be suppressed.

Embodiment 3.
The heat exchanger 300 according to the third embodiment differs from the heat exchanger 100 according to the first embodiment in the structure of the plurality of flat tubes 20. The third embodiment will be described focusing on the changes from the first embodiment.

FIG. 17 is a diagram showing hydrophilicity of the surfaces of the plurality of flat tubes 20 of the heat exchanger 300 according to the third embodiment. The plurality of flat tubes 20 of the heat exchanger 200b are configured by joining the refrigerant circulation portion 50 and the fin portion 51, which are manufactured as separate members. The plate-shaped member 60 forming the fin portion 51 is formed by bending, for example, a metal plate material, and is joined to the end portion 21 of the refrigerant flow portion 50 by means of brazing or the like. The hydrophilicity of the entire surface of the plate-shaped member 60 forming the fin portion 51 is lower than that of the surface of the refrigerant flow portion 50. With this configuration, of the second side surfaces 25b of the plurality of flat tubes 20, only the region F in which the plate-shaped member 60 and the refrigerant flow portion 50 face each other faces the different hydrophilic surface. There is. Therefore, the gap formed by the region F and the plate-shaped member 60 has different hydrophilic surfaces facing each other, and the retention of water droplets is suppressed as in the gap of the plurality of flat tubes 20 of the first embodiment. Can be done.

In the third embodiment, the plurality of flat tubes 20 have different hydrophilic surfaces facing each other only in a part of the first side surface 25a and the second side surface 25b. However, when the heat exchanger 300 is used as an evaporator, it is possible to suppress the retention of water droplets on the windward side where dew condensation is most likely to occur, which is advantageous over the

heat exchangers

1100 and 2100 of the comparative example. Further, even when the region F is arranged on the leeward side, the water droplets moved to the leeward side due to the air flow are easily discharged in the region F, which is advantageous to the

heat exchangers

1100 and 2100 of the comparative example. ..

In the third embodiment, the refrigerant flow section 50 is a region having low hydrophilicity as a whole, but is different between the first side surface 25a side and the second side surface 25b side as in the first embodiment. You may comprise so that it may become hydrophilic. However, like the plurality of flat tubes 20 of the heat exchanger 300 according to Embodiment 3, the entire surface of the refrigerant circulation portion 50 has a low hydrophilic surface, and the entire surface of the fin portion 51 has a high hydrophilic surface. By doing so, there is an advantage that the plate-shaped member 60 forming the coolant circulation portion 50 and the fin portion 51 can be easily manufactured.

Fourth Embodiment
The heat exchanger 400 according to the fourth embodiment is different from the heat exchanger 100 according to the first embodiment in the structure of the plurality of flat tubes 20. The fourth embodiment will be described focusing on the changes from the first embodiment.

FIG. 18 is a diagram showing a hydrophilic property of the surfaces of the plurality of flat tubes 20 of the heat exchanger 400 according to the fourth embodiment. The plurality of flat tubes 20 of the heat exchanger 400 are arranged in the Y direction from the refrigerant circulation part 50 in which the plurality of refrigerant flow paths 24 through which the refrigerant flows are provided, and the longitudinal end 21 of the refrigerant circulation part 50. A fin portion 51 extending toward the end portion and a fin portion 52 extending from the end portion 22 in the Y direction opposite direction. The fin portion 52 is a plate-shaped portion that projects from the end portion 22 in the Y direction in the opposite direction and is installed along the tube axes of the plurality of flat tubes 20.

The plurality of flat tubes 20 of the heat exchanger 400 are configured by joining the refrigerant circulation unit 50 and the plate member 460, which are manufactured as separate members. The plate-shaped member 460 forming the

fin portions

51 and 52 is formed by bending a metal plate material, for example, and is attached so as to cover one side surface of the refrigerant circulating portion 50, and a joining means such as brazing is used. It is joined to the refrigerant flow unit 50. The plate-shaped member 460 forming the fin portions 51 and the fin portions 52 has lower hydrophilicity on the entire surface than that of the surface of the coolant circulation portion 50. On the other hand, the hydrophilicity of the entire surface of the coolant circulation portion 50 is higher than that of the surface of the plate member 460. Desirably, the surface of the plate member 460 has a contact angle θ1<90°, and the surface of the refrigerant flow portion 50 has a contact angle θ2≧90°. The plate-shaped member 460 and the refrigerant flow section 50 have an advantage that they can be easily manufactured because their respective surfaces are configured to have the same hydrophilicity.

In the heat exchanger 400, the first flat tube 20a and the second flat tube 20b have at least one refrigerant flow section 50 including a refrigerant flow path 24 through which a refrigerant passes, and an end portion 21 of the refrigerant flow section 50. , 22, and two

fin portions

51 and 52 extending in the long axis direction. Therefore, since the fin portions 51 and the fin portions 52 extend from both ends of the refrigerant flow portion 50, the contact area with the air passing between the plurality of flat pipes 20 increases, and the heat exchange efficiency becomes high. .. The plate-shaped member 460 forming the

fin portions

51 and 52 forms the first side surface 25a of the first flat tube 20a, and constitutes a part of the second side surface 25b of the second flat tube 20b. It faces the distribution unit 50. With this configuration, in the heat exchanger 400, the first side surface 25a having high hydrophilicity and the second side surface 25b having low hydrophilicity are arranged to face each other, and the refrigerant flow section 50 having the narrowest interval is arranged. In the gap between them, the retention of water droplets can be suppressed as in the first embodiment.

The plurality of flat tubes 20 of the heat exchanger 400 are formed by joining the refrigerant circulating portion 50 and the separate plate-shaped member 460, but the refrigerant circulating portion 50 and the

fin portions

51, 52 are integrated. It may be manufactured in In this case, the plurality of flat tubes 20 are manufactured by, for example, extrusion processing or drawing processing. However, when the refrigerant flow section 50 and the

fin sections

51 and 52 are integrated in the plurality of flat tubes 20 of the heat exchanger 400, at least the first side surface 25a side and the second side surface 25b side of the refrigerant flow section 50 are included. It is necessary to form the hydrophilic properties of the surface differently.

Embodiment 5.
The heat exchanger 500 according to the fifth embodiment differs from the heat exchanger 200 according to the second embodiment in that the arrangement of the plurality of flat tubes 20 is changed. The fifth embodiment will be described focusing on the changes from the second embodiment.

FIG. 19 is a diagram showing a hydrophilic property of the surfaces of the plurality of flat tubes 520 of the heat exchanger 500 according to the fifth embodiment. In the first flat pipe 520a constituting the plurality of flat pipes 520 of the heat exchanger 500, the fin portion 51 extends in the opposite direction in the Y direction from the end portion 21 of the refrigerant flow portion 50. Further, in the second flat tubes 520b that form the plurality of flat tubes 520, the fin portions 52 extend in the Y direction from the end portions 22 of the refrigerant circulating portion 50. The first flat tubes 520a and the second flat tubes 520b do not have the refrigerant circulation parts 50 arranged in parallel in the X direction, and the refrigerant circulation parts 50 of the second flat tubes 520b are displaced in the Y direction. Have been placed. That is, the fin portion 51 of the first flat tube 520a and the refrigerant flowing portion 50 of the second flat tube 520b face each other, and the fin flowing portion 50 of the first flat tube 520a and the fin portion of the second flat tube 520b. 52 are arranged so as to face each other. In other words, the first flat tube 520a and the second flat tube 520b are arranged such that one refrigerant circulating portion 50 and the

other fin portions

51 and 52 face each other.

The plurality of flat tubes 520 of the heat exchanger 500 are configured such that the

fin portions

51 and 52 have high hydrophilicity and the refrigerant flow portion 50 has low hydrophilicity. Accordingly, in the gap formed by the first flat tube 520a and the second flat tube 520b adjacent to each other, the surfaces facing each other have different hydrophilic properties, so that the heat exchanger 500 is similar to the first embodiment. The retention of water droplets can be suppressed.

Sixth Embodiment
The heat exchanger 600 according to the sixth embodiment differs from the heat exchanger 100 according to the first embodiment in the structure and arrangement of the plurality of flat tubes 20. The sixth embodiment will be described focusing on the changes from the first embodiment.

FIG. 20 is an explanatory diagram of a sectional structure of the heat exchanger 600 according to the sixth embodiment. FIG. 20 shows a cross section perpendicular to the tube axis of the plurality of flat tubes 20. The plurality of flat tubes 620 are composed of a first flat tube 620a and a second flat tube 620b. Each of the plurality of flat tubes 620 is provided with a plurality of refrigerant circulation portions 50, and is formed by connecting the end portion 21 of one refrigerant circulation portion 50 and the end portion 22 of the other refrigerant circulation portion 50 by the fin portion 53. ing. Further, in the plurality of flat tubes 620,

fin portions

51 and 52 are extended from the

end portions

21 and 22 that are not connected to the other refrigerant circulation portions 50.

As in the other embodiments, the plurality of flat tubes 620 have the first side surface 25a and the second side surface 25b facing each other. The first side surface 25a has a high hydrophilicity and the second side surface 25b has a low hydrophilicity at least in the gap between the refrigerant circulation portions 50 having a narrow interval. With this configuration, the heat exchanger 600 can suppress the retention of water droplets as in the first embodiment while having a large heat exchange capacity.

FIG. 21 is an explanatory diagram of a cross-sectional structure of a heat exchanger 600a which is a modified example of the heat exchanger 600 according to the sixth embodiment. Similar to the heat exchanger 600, the plurality of flat tubes 620 of the heat exchanger 600a are configured by connecting the plurality of refrigerant circulation portions 50 by the fin portions 53. The heat exchanger 600a is positioned so that the refrigerant flow section 50 of the second flat tube 620b is displaced in the Y direction with respect to the refrigerant flow section 50 of the first flat tube 620a. That is, the fin portion 51 and the fin portion 53 of the first flat tube 620a and the refrigerant flowing portion 50 of the second flat tube 620b face each other, and the refrigerant flowing portion 50 of the first flat tube 620a and the second flat tube 620a. The fin portion 52 of the 620b is arranged so as to face the fin portion 52. In other words, the first flat tube 620a and the second flat tube 620b are arranged such that one refrigerant circulating portion 50 and the

other fin portions

51, 52, 53 face each other.

The plurality of flat tubes 620 of the heat exchanger 600a are configured so that the surface hydrophilicity of the

fin portions

51, 52, 53 is high and the hydrophilicity of the surface of the refrigerant flow portion 50 is low. With such a configuration, in the gap formed by the first flat tube 520a and the second flat tube 520b adjacent to each other, the opposing surfaces have different hydrophilic properties. Therefore, the heat exchanger 600a has a large heat exchange capacity and can suppress the retention of water droplets as in the first embodiment.

Further, in the sixth embodiment, the plurality of flat pipes 620 are integrally formed with the refrigerant flow portion 50 and the

fin portions

51, 52, 53, but even if they are configured by joining different members to each other. good. For example, as shown in the fourth embodiment, the plurality of flat tubes 620 can be easily manufactured by joining the plate-like members forming the

fin portions

51, 52, 53 and the refrigerant circulating portion 50 to each other. Has the advantage that

Although the present invention has been described above based on the embodiments, the present invention is not limited to the configurations of the above-described embodiments. For example, the plurality of flat tubes 620 have two refrigerant circulation parts 50, but may have more refrigerant circulation parts 50. Further, the

heat exchangers

100, 200, 200a, 300, 400, 500, 600, 600a may further include flat tubes having different hydrophilic properties. Further, in the above description, the index of hydrophilicity is described as low hydrophilicity when the contact angle between the water droplet and the surface is large, and high hydrophilicity when the contact angle is small. The magnitude of the fall angle may be used instead of the magnitude of the contact angle. That is, when the falling angle is small, the hydrophilicity is low (water releasability is high), and when the falling angle is large, the hydrophilicity is high (water releasability is low). You may. Further, the present invention may be configured by combining each embodiment. For example, the bent cross-sectional shapes of the plurality of flat tubes 120 of the heat exchanger 100A, which is a modification of the heat exchanger 100 according to the first embodiment, may be applied to other embodiments. In short, it should be added that the scope of the present invention (technical scope) also includes various modifications, applications, and ranges of use that are required by those skilled in the art.

1 refrigeration cycle device, 2 blower, 3 compressor, 4 four-way valve, 5 outdoor heat exchanger, 6 expansion device, 7 indoor heat exchanger, 8 outdoor unit, 9 indoor unit, 10 outdoor heat exchanger, 20 flat tube, 20a first flat tube, 20b second flat tube, 21 (first) end, 22 (second) end, 24 refrigerant flow passage, 25a (first) side surface, 25b (second) side surface , 50 refrigerant flow section, 51 fin section, 52 fin section, 53 fin section, 60 plate-shaped member, 70 water droplets, 70a water droplets, 70b water droplets, 80 lower end header, 81 upper end header, 90 refrigerant piping, 100 heat exchanger, 101 Heat exchanger unit, 200 heat exchanger, 200a heat exchanger, 200b heat exchanger, 300 heat exchanger, 400 heat exchanger, 460 plate-shaped member, 500 heat exchanger, 520 flat tube, 520a first flat tube , 520b 2nd flat tube, 600 heat exchanger, 600a heat exchanger, 620 flat tube, 620a 1st flat tube, 620b 2nd flat tube, 1020 flat tube, 1020a 1st flat tube, 1020b 2nd 1025a (first) side surface, 1025b (second) side surface, 1070 water droplets, 1100 heat exchanger, 2020 flat tube, 2020a first flat tube, 2020b second flat tube, 2025a first Side surface, 2025b second side surface, 2070 water droplet, 2100 heat exchanger, A tube minor diameter, B pitch, F region, G gravity, γs surface tension, γsw interfacial tension, γw surface tension, θ contact angle, θ1 contact angle, θ2 contact angle.

Claims

A first flat tube and a second flat tube whose tube axes are arranged in parallel,
The first flat tube has a first side surface facing the second flat tube,
The second flat tube has a second side surface facing the first flat tube,
The hydrophilic region, which is at least a part of the first side surface,
A heat exchanger that is more hydrophilic than the second side surface.
The contact angle of the hydrophilic region on the first side surface is
The heat exchanger according to claim 1, which is smaller than the contact angle of a region of the second side surface facing the hydrophilic region.
The contact angle of the hydrophilic region of the first side surface is
Less than 90°,
The contact angle of a region of the second side surface facing the hydrophilic region is
The heat exchanger according to claim 2, wherein the temperature is 90 ° or more.
The falling angle of the hydrophilic region on the first side surface is
The heat exchanger according to any one of claims 1 to 3, which has a larger fall angle than a region of the second side surface facing the hydrophilic region.
The first flat tube and the second flat tube
At least one refrigerant flow unit having a refrigerant flow path for passing refrigerant inside,
The heat exchanger according to any one of claims 1 to 4, further comprising: at least one fin portion extending in a long axis direction in a cross section perpendicular to the tube axis from an end portion of the refrigerant circulation portion.
The first flat tube and the second flat tube,
The heat exchanger according to claim 5, wherein one of the refrigerant circulation portions and the other of the fin portions are arranged to face each other.
The first flat tube and the second flat tube,
The heat exchanger according to claim 5, wherein the refrigerant circulation portion and the fin portion are arranged to face each other.
The first flat tube and the second flat tube
It is formed by joining the fin portion and the refrigerant flow portion.
The fin portion is
The heat exchanger according to claim 6 or 7, which is formed by being joined to one side surface of the two side surfaces along the long axis direction of the refrigerant circulating portion.
The surface of the fin portion is
The heat exchanger according to claim 8, wherein hydrophilicity is different from that of the surface of the refrigerant circulation portion.
The fin portion is
Has a plurality of fins,
The heat exchanger according to any one of claims 5 to 9, which is extended from both ends of the refrigerant circulation portion in the long axis direction in the long axis direction.
The refrigerant circulation unit,
Having a plurality of refrigerant circulation parts,
The ends of the two adjacent refrigerant circulation portions of the plurality of refrigerant circulation portions are
The heat exchanger according to any one of claims 5 to 10, wherein the heat exchangers are connected by the fin portions.
The first flat tube and the second flat tube
The heat exchanger according to any one of claims 1 to 11, wherein a member that connects the first side surface and the second side surface is not provided.
A heat exchanger unit comprising the heat exchanger according to any one of claims 1 to 12.
A refrigeration cycle apparatus including the heat exchanger unit according to claim 13.