WO2024150465A1 - Heat exchanger and outdoor unit - Google Patents

Abstract

Provided are a heat exchanger and an outdoor unit with which heat exchange performance can be improved.　This heat exchanger comprises a plurality of flat pipes 62 arranged at prescribed intervals in a vertical direction of a header pipe, and a plurality of header pipes having the two end portions of the flat pipes 62 connected thereto, wherein, when the heat exchanger is functioning as an evaporator: a connecting pipe for supplying a gas-liquid two-phase refrigerant is connected to a lower portion of at least one of the header pipes; the interior of the header pipe to which the connecting pipe is connected is provided with a separating wall plate for partitioning the same into a first space extending in a vertical direction and communicating with the connecting pipe, and a second space communicating with the flat pipes 62; and a plurality of communicating holes providing communication between the first space and the second space are provided in the separating wall plate above a connection position of the connecting pipe.

Description

Heat exchanger and outdoor unit

This disclosure relates to a heat exchanger and an outdoor unit.

Patent Document 1 discloses a heat exchanger and a refrigeration cycle device that can equalize the refrigerant supplied to the heat transfer tubes. This heat exchanger has a first header, a second header, a plurality of heat transfer tubes, and a partition plate. The first header and the second header extend vertically and are arranged at intervals from each other. The heat transfer tube is connected between the first header and the second header. The connecting tube is connected to the first header and supplies gaseous refrigerant and liquid refrigerant to the inside of the first header. The partition plate extends vertically and divides the inside of the first header into a first space on the connecting tube side and a second space on the heat transfer tube side. The connecting tube has an upper opening and a lower opening at the top and bottom, respectively. A communication passage that communicates between the first space and the second space is formed below the partition plate. The partition plate has a plurality of communication holes in the vertical direction that communicate between the first space and the second space.

JP 2004-125210 A

This disclosure provides a heat exchanger and an outdoor unit that can improve heat exchange performance.

This specification includes the entire contents of Japanese Patent Application No. 2023-002543 filed on January 11, 2023.
The heat exchanger of the present disclosure is a heat exchanger comprising a plurality of flat tubes arranged at a predetermined interval in the vertical direction of a header pipe, and a plurality of the header pipes to which both ends of each of the flat tubes are connected, wherein when the heat exchanger functions as an evaporator, a connecting pipe for supplying a gas-liquid two-phase refrigerant is connected to the lower part of at least one of the header pipes, and a partition plate is provided inside the header pipe to which the connecting pipe is connected, dividing the space into a first space extending in the vertical direction and communicating with the connecting pipe, and a second space communicating with the flat tubes, and the partition plate is provided with a plurality of communication holes communicating between the first space and the second space above the connection position of the connecting pipe.

This disclosure makes it possible to improve heat exchange performance.

FIG. 1 is a perspective view of an outdoor unit according to a first embodiment of the present disclosure. FIG. 2 is a plan view of the outdoor unit. FIG. 3 is a perspective view of an outdoor heat exchanger. FIG. 4 is a vertical cross-sectional view showing a schematic internal structure of the outdoor heat exchanger. FIG. 5 is a diagram showing a partition plate. FIG. 6 is a cross-sectional view showing a schematic internal structure of the outdoor heat exchanger. FIG. 7 is a diagram showing the performance of a heat exchanger provided with a partition plate and a heat exchanger without a partition plate. FIG. 8 is a vertical cross-sectional view that illustrates an internal structure of an outdoor heat exchanger according to a first modified example. FIG. 9 is a diagram showing a partition plate according to a second modified example. FIG. 10 is a cross-sectional view that illustrates a schematic internal structure of an outdoor heat exchanger according to a second modified example.

(The knowledge and other information that formed the basis of this disclosure)
At the time when the inventors came up with the present disclosure, there was a technology in a heat exchanger in which a gas refrigerant and a liquid refrigerant were intentionally phase-separated inside a header pipe, and then the gas refrigerant was distributed along the vertical direction of the header pipe and sent to the flat tubes together with the liquid refrigerant. In this heat exchanger, a partition plate is provided in the internal space of the header pipe, thereby dividing the internal space into a first space on the connecting pipe side that supplies a two-phase gas-liquid refrigerant consisting of gas refrigerant and liquid refrigerant to the header pipe, and a second space on the flat tube side. An upper opening and a lower opening are formed at the upper and lower parts of the connecting pipe, respectively. As a result, in this heat exchanger, the refrigerant supplied to the heat transfer tubes can be made uniform.

However, in the above-mentioned heat exchanger, the flow pattern of the gas-liquid two-phase refrigerant flowing through the connecting pipe changes depending on the operating conditions, so that the header pipe may not separate into gas refrigerant and liquid refrigerant under all operating conditions. In the above-mentioned heat exchanger, the gas-liquid two-phase refrigerant flows into the second space of the header pipe through the lower opening. As a result, the amount of liquid refrigerant contributing to heat transfer is greater in the flat tubes located at the lower part than in the flat tubes located at the upper part due to gravity. Therefore, the inventors have discovered a problem that the amount of liquid refrigerant supplied in the above-mentioned heat exchanger is biased depending on the arrangement height of the flat tubes, and the heat exchange performance is reduced. In order to solve this problem, the present disclosure has been formed as a subject of the present disclosure.
In view of this, the present disclosure provides a heat exchanger and an outdoor unit that can improve heat exchange performance.

Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming more redundant than necessary and to facilitate understanding by those skilled in the art.
It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to Figures 1 to 6. The symbol FR in each figure indicates the front of the outdoor unit 1 when it is installed on an installation surface and in normal use, the symbol UP indicates the upper side of the outdoor unit 1, and the symbol LH indicates the left side of the outdoor unit 1. In the following description, each direction is along the direction of the outdoor unit 1.

[1-1. Configuration]
[1-1-1. Configuration of outdoor unit]
FIG. 1 is a perspective view of an outdoor unit 1 of an air conditioner according to the present embodiment.
The air conditioner of this embodiment includes an indoor heat exchanger housed in an indoor unit, and a refrigeration circuit formed by a compressor 5, an expansion valve, an outdoor heat exchanger 50, etc. housed in an outdoor unit 1. The air conditioner conditions the conditioned space in which the indoor unit is provided by circulating a refrigerant through this refrigeration circuit.

As shown in FIG. 1, the outdoor unit 1 of this embodiment is a so-called side-flow type, or side-blowing type, outdoor unit that draws air in through an outdoor heat exchanger 50 arranged on one side, exchanges heat with the refrigerant, and blows the air out from the other side.

Fig. 2 is a plan view showing a schematic diagram of the internal structure of the outdoor unit 1. For ease of explanation, in Fig. 2, the edge of the bottom plate 12 forming the lower edge of the front air intake 15 and the side air intake 17, and a predetermined part of the back plate 18 forming the edge of the exhaust port 19 are shown by dashed lines. In Fig. 2, the direction of air flow by the blower fan 30 is shown by a dashed double-dashed arrow A.
The outdoor unit 1 includes a box-shaped housing 10 whose longitudinal direction extends along the left-right direction, as shown in Figures 1 and 2. In this embodiment, each part of the housing 10 is formed from a steel plate.
The housing 10 comprises a bottom plate 12 that forms the bottom surface of the housing 10, a top plate 14 that forms the top surface, a front plate 16 that forms the front surface, a back plate 18 that forms the back surface, a left side plate 11 that forms the left side surface, and a right side plate 13 that forms the right side surface.

1 , a front air intake 15 is provided on the front panel 16. The front air intake 15 is a rectangular opening through which air is drawn from the outside to the inside of the housing 10. On the front panel 16, the front air intake 15 is provided at a position closer to the left side panel 11 than to the right side panel 13.
A plurality of fastening holes 20, which are through holes, are provided in the front plate 16 at positions close to the edge of the front air intake port 15 on the side of the right side plate 13. These fastening holes 20 are provided so as to be aligned on the same straight line extending along the vertical direction of the housing 10. In this embodiment, three fastening holes 20 are provided in the front plate 16.

A side air intake port 17 is provided in the left side plate 11. The side air intake port 17 is a rectangular opening through which air is drawn into the inside of the housing 10. On the left side plate 11, the side air intake port 17 is provided at a position closer to the front plate 16 than to the back plate 18.
Three fastening holes 20 are provided on the left side plate 11 near the edge of the side air intake 17 on the rear plate 18 side so as to be aligned in the same straight line extending along the vertical direction of the housing 10.

2, the rear panel 18 is provided with an exhaust port 19. The exhaust port 19 is an opening through which air drawn into the housing 10 is blown out to the outside of the housing 10.
The front air intake 15, the side air intake 17, and the exhaust vent 19 may be provided with a filter or a lattice-shaped protective member.

The internal space S of the housing 10 is divided into two spaces by a partition plate 21. The partition plate 21 is a plate-like member that extends with a predetermined height dimension along the up-down direction of the housing 10 and also along the front-rear direction of the housing 10. The partition plate 21 is fixed to the housing 10 by having its lower end connected to the bottom plate 12. The partition plate 21 has an end portion located on the front side of the housing 10 connected to the front plate 16, and an end portion located on the rear side of the housing 10 connected to the rear plate 18.
As a result, two spaces are created inside the housing 10, separated by a partition plate 21: a machine chamber S1 located on the right side of the housing 10, and a blower chamber S2 located on the left side of the housing 10.

The machine chamber S1 accommodates the compressor 5, an expansion valve, a header pipe 52 provided in the outdoor heat exchanger 50, components constituting the refrigeration circuit such as refrigerant piping, various electric components, and the like.
The blower chamber S2 accommodates the blower fan 30 and the exterior heat exchanger 50 excluding the header pipe 52.

The blower fan 30 is an axial flow fan that rotates to introduce air from outside the housing 10 into the blower chamber S2, exchanges heat with the refrigerant flowing through the outdoor heat exchanger 50, and then releases the air back outside the housing 10. The blower fan 30 includes a fan motor 32 and an impeller 34.
The fan motor 32 is a drive unit that rotates the impeller 34, and the fan motor 32 includes a drive shaft 36 to which the impeller 34 is attached.
The impeller 34 is a rotating part that is rotated by the fan motor 32 to send out air in the axial flow direction.
The blower fan 30 is disposed at a position where the impeller 34 faces the exhaust port 19 and where the tip of the drive shaft 36 faces the exhaust port 19 .

In this embodiment, when the blower fan 30 is driven to rotate, it causes air to flow from the outside of the outdoor unit 1 into the inside of the housing 10, i.e., into the blower chamber S2. Specifically, as shown by arrow A in FIG. 2, air flows into the blower chamber S2 mainly from the front air intake 15 and the side air intake 17.

[1-1-2. Configuration of outdoor heat exchanger]
Fig. 3 is a perspective view showing the outdoor heat exchanger 50. For ease of explanation, Fig. 3 shows the outdoor heat exchanger 50 formed in a straight line in a plan view. In Fig. 3, the direction of air flow by the blower fan 30 is indicated by a two-dot chain line arrow A.
The outdoor heat exchanger 50 is a heat exchanger in which a flow path through which a refrigerant flows is formed, and which functions as an evaporator that evaporates the refrigerant supplied from the indoor unit, or as a condenser that condenses the refrigerant.
As shown in FIG. 3 , the outdoor heat exchanger 50 includes a pair of header pipes 52 , a connecting header pipe 54 , a first refrigerant pipe 66 , a second refrigerant pipe 68 , a plurality of flat tubes 62 , and a plurality of fins 64 .
In the present embodiment, all of these members included in the outdoor heat exchanger 50 are formed from so-called aluminum material made of aluminum or an aluminum alloy.

Each of the header pipes 52 is a hollow columnar member whose longitudinal direction extends along the up-down direction of the housing 10. In the present embodiment, each of the header pipes 52 is formed in a cylindrical shape. Each of these header pipes 52 is provided at one end of the outdoor heat exchanger 50 in the longitudinal direction.
An internal space SP of the header pipe 52 is provided inside the header pipe 52 .

A first refrigerant pipe 66 is connected to one header pipe 52, and a second refrigerant pipe 68 is connected to the other header pipe 52. The first refrigerant pipe 66 and the second refrigerant pipe 68 function as an inlet and an outlet of the refrigerant in the outdoor heat exchanger 50.
The first refrigerant pipe 66 is connected to an upper portion of the side surface 51 of one of the header pipes 52. The second refrigerant pipe 68 is connected to a lower portion of the side surface 51 of the other header pipe 52.
The second refrigerant pipe 68 corresponds to the “connecting pipe” in this disclosure.

The connecting header pipe 54 is a hollow columnar member whose longitudinal direction extends along the up-down direction of the housing 10 .
An internal space SQ is provided inside the connection header pipe 54. The connection header pipe 54 is provided at the other end of the outdoor heat exchanger 50 in the longitudinal direction.

The flat tubes 62 are long, flat tubular members that have a refrigerant flow path therein through which the refrigerant flows.
Each flat tube 62 is arranged along the longitudinal direction of each header pipe 52 and the connecting header pipe 54 so that their respective longitudinal directions are parallel to each other, and each of the two ends of the flat tube 62 is connected to each of the side surfaces 51 of each header pipe 52 and the side surface 53 of the connecting header pipe 54.

That is, one end of each of the flat tubes 62 is connected to a predetermined location on the side surface 51 of each header pipe 52 in a row at a predetermined interval along the longitudinal direction of the header pipe 52. Similarly, the other end of each of the flat tubes 62 is connected to a predetermined location on the side surface 53 of the connecting header pipe 54 in a row at a predetermined interval along the longitudinal direction of the connecting header pipe 54.
Therefore, the longitudinal direction of each flat tube 62 coincides with the longitudinal direction of the outdoor heat exchanger 50 .

Each flat tube 62 is connected to each header pipe 52 and the connecting header pipe 54 so that their width directions are parallel to each other. The width direction is perpendicular to each of the longitudinal direction of each flat tube 62, the plate thickness direction of each flat tube 62, and the longitudinal direction of each header pipe 52.

On the side surface 51 of each header pipe 52, the predetermined location to which the flat tubes 62 are connected is located on the opposite side of the internal space SP to the predetermined location to which either the first refrigerant piping 66 or the second refrigerant piping 68 is connected.

Hereinafter, in this embodiment, a predetermined location on the side surface 51 of each header pipe 52 where each flat tube 62 is connected is referred to as a connection side surface 55, and a predetermined location on the side surface 53 of the connecting header pipe 54 where each flat tube 62 is connected is referred to as a connection side surface 57. Also, in this embodiment, a predetermined location on the side surface 51 of each header pipe 52 where either the first refrigerant piping 66 or the second refrigerant piping 68 is connected is referred to as a connection side surface 59.
That is, the connection side surface 57 is located on the side surface 51 of each header pipe 52 opposite the connection side surface 59 with the internal space SP interposed therebetween.

The flat tubes 62 extending from each of the header pipes 52 are all connected to the connection side surface 57 such that the other ends are aligned in a direction intersecting the longitudinal direction of the connecting header pipe 54 .
In the present embodiment, the flat tubes 62 extending from each of the header pipes 52 are all connected to the connection side surface 57 such that the other ends are aligned in a direction perpendicular to the longitudinal direction of the connecting header pipe 54. In other words, the flat tubes 62 aligned in a direction perpendicular to the longitudinal direction of the connecting header pipe 54 are positioned at approximately the same height as each other in the up-down direction of the housing 10.
As a result, each of the header pipes 52 is connected to the connecting header pipe 54 via the flat tubes 62 .

Each flat tube 62 has an opening at both ends. One end of each flat tube 62 opens into the internal space SP, and the other end opens into the internal space SQ.

The multiple fins 64 are flat plate members having multiple insertion holes formed on a plane, through which each of the flat tubes 62 can be inserted. Each of the flat tubes 62 is connected to each of the header pipes 52, 54 while being inserted through each of the fins 64. That is, each of the fins 64 is arranged with its longitudinal direction and width direction perpendicular to each of the flat tubes 62. The longitudinal direction of each of the fins 64 arranged in this manner coincides with the longitudinal direction of each of the header pipes 52, 54.
In this embodiment, the pair of header pipes 52, the connecting header pipe 54, the first refrigerant piping 66, the second refrigerant piping 68, the plurality of flat tubes 62, and the plurality of fins 64 are fixed to each other by so-called brazing using a brazing material.

In the blower chamber S2, the outdoor heat exchanger 50 is arranged such that its longitudinal direction runs along the front panel 16 and the left side panel 11. Specifically, the header pipe 52 is arranged close to the edge of the front air intake 15 on the right side panel 13 side, and the connecting header pipe 54 is arranged close to the edge of the side air intake 17 on the back panel 18 side. The outdoor heat exchanger 50 is then bent and arranged close to the corner 23 of the housing 10 formed by the front panel 16 and the left side panel 11.

The outdoor unit 1 includes a fixing member 70 that fixes the outdoor heat exchanger 50 to the housing 10 .
Specifically, the header pipes 52 included in each of the outdoor heat exchangers 50 are fixed to the front panel 16 by a plurality of fixing members 70. In the present embodiment, each header pipe 52 is fixed by three fixing members 70.
In the outdoor heat exchanger 50 fixed to the housing 10 in this manner, the longitudinal direction of each header pipe 52 and the connecting header pipe 54 are all arranged along the up-down direction of the housing 10 .

In the outdoor heat exchanger 50 fixed to the housing 10, one header pipe 52 and the flat tubes 62 connected to the header pipe 52 are positioned at a position farther away from the side of the housing 10 than the other header pipe 52 and the flat tubes 62 connected to the header pipe 52, in other words, at a position closer to the blower fan 30.
For this reason, in the direction of air flow by the blower fan 30, the flat tubes 62 connected to one header pipe 52 are located upstream of the flat tubes 62 connected to the other header pipe 52. In other words, each of the flat tubes 62 extending from each of the pair of header pipes 52 is aligned along the direction of air flow by the blower fan 30, which is a direction perpendicular to the longitudinal direction of the connecting header pipe 54.

As shown in FIG. 1, the outdoor heat exchanger 50 is fixed to the housing 10, and most of the flat tubes 62 and fins 64 are exposed from the housing 10 through the front air intake 15 and the side air intake 17. Meanwhile, the header pipe 52 is shielded by the front plate 16, and the connecting header pipe 54 is shielded by the left side plate 11.

The partition plate 21 is arranged to pass between the header pipe 52 and the multiple fins 64. As a result, the header pipe 52 is arranged in the machine room S1, and the multiple flat tubes 62, fins 64, and connecting header pipe 54 are arranged in the blower room S2.

[1-1-2. Header pipe configuration]
4 is a vertical cross-sectional view that typically illustrates the internal structure of the outdoor heat exchanger 50. In FIG. 4, a vertical cross-section of the outdoor heat exchanger 50 is shown that is cut along a plane that is parallel to the direction in which the flat tubes 62 extend and that passes through the communication holes 81 of the header pipes 52.
4, a partition plate 80 is provided in the internal space SP of the header pipe 52 to which the second refrigerant pipe 68 is connected. The partition plate 80 is a plate-like member having a predetermined thickness.

The partition plate 80 extends over the entire longitudinal direction of the header pipe 52, and both ends abut against the top and bottom surfaces of the header pipe 52. The partition plate 80 is disposed in the internal space SP such that its plane is parallel to the longitudinal direction of the header pipe 52 and the width direction of the flat tubes 62.
As a result, the internal space SP of the header pipe 52 is divided into a first space SP1 located on the connection side surface 59 side and a second space SP2 located on the connection side surface 55 side.

The partition plate 80 is provided in the internal space SP at a position closer to the connection side 59 than to the connection side 55. This makes the first space SP1 smaller than the second space SP2.

Fig. 5 is a diagram showing the partition plate 80. Fig. 5 shows a plan view of the partition plate 80 as viewed from the direction in which the flat tubes 62 extend. For ease of explanation, in Fig. 5, the flat tubes 62 are indicated by dashed lines, the second refrigerant piping 68 is indicated by dashed lines, and the direction of air flow by the blower fan 30 is indicated by a two-dot chain arrow A.
As shown in FIG. 5 , the partition plate 80 extends so as to overlap the entire opening of each of the flat tubes 62 when viewed from the direction in which the flat tubes 62 extend.

5, the partition plate 80 is provided with a communication hole 81 which is a through hole penetrating in the plate thickness direction. The communication hole 81 communicates the first space SP1 and the second space SP2 in the internal space SP.
In the partition plate 80, a plurality of communication holes 81 are arranged at predetermined intervals along the longitudinal direction of the header pipe 52. In a plan view, these communication holes 81 have a dimension along the longitudinal direction of the header pipe 52 that is longer than the thickness dimension in the plate thickness direction of the flat tubes 62. This prevents the communication holes 81 from acting as a flow resistance for the refrigerant, and makes it easier for the refrigerant flowing through the header pipe 52 to flow into the communication holes 81.

The communication hole 81 is provided in the longitudinal direction of the header pipe 52 above the location to which the second refrigerant piping 68 is connected. That is, the second refrigerant piping 68 and the flat tubes 62 are separated by the partition plate 80 when viewed from the longitudinal direction of the flat tubes 62.
This prevents the refrigerant that has flowed from the second refrigerant piping 68 into the header pipe 52 from moving straight and flowing into the flat tubes 62 located near the flow direction of the refrigerant. As a result, in the outdoor heat exchanger 50, the refrigerant that has flowed into the header pipe 52 moves upward along the partition plate 80, preventing drift in the flow due to the arrangement position of the flat tubes 62 in the height direction of the header pipe 52. Furthermore, in the outdoor heat exchanger 50, the refrigerant is prevented from being unevenly distributed to each of the flat tubes 62.

The communication hole 81 has a length dimension that is shorter than the opening of the flat tube 62 in a direction perpendicular to the longitudinal direction of the partition plate 80, in other words, in the direction of air flow by the blower fan 30. This makes it possible to easily form the communication hole 81 in the partition plate 80 while suppressing a decrease in the strength and rigidity of the partition plate 80.

The communication hole 81 is provided in the width direction of the flat tube 62 at a position overlapping the end located upstream in the direction of air flow by the blower fan 30 when viewed from the direction in which the flat tube 62 extends. This allows the outdoor heat exchanger 50 to preferentially send the refrigerant that has flowed into the header pipe 52 to a location in the flat tube 62 that is upstream in the direction of air flow. Therefore, in the outdoor heat exchanger 50, the refrigerant can be preferentially sent to a location in the flat tube 62 where the air flows before heat exchange with the refrigerant.

[1-2. Operation]
The operation of the outdoor unit 1 configured as above will now be described.

First, the flow of refrigerant in the air conditioner will be described.
When the air conditioner performs heating operation, the outdoor unit 1 starts operating and the compressor 5 is driven. The compressor 5 compresses the refrigerant sealed in the refrigeration circuit, and sends out the gas refrigerant through each refrigerant pipe.

After releasing heat and being condensed in the indoor heat exchanger, this gas refrigerant flows through the piping into the expansion valve, is decompressed by the expansion valve, and flows through the second refrigerant piping 68 into the internal space SP of the other header pipe 52. The refrigerant that flows into the internal space SP flows through each flat tube 62 into the internal space SQ of the connecting header pipe 54. The refrigerant then flows toward the one header pipe 52 through each flat tube 62 connected to one header pipe 52. The refrigerant flowing through the outdoor heat exchanger 50 absorbs heat and evaporates by exchanging heat with the air sent out by the blower fan 30 in the flat tubes 62. That is, the outdoor heat exchanger 50 functions as an evaporator.
The refrigerant evaporated in the flat tubes 62 flows into the internal space SP of one of the header pipes 52 , and then returns to the compressor 5 through the first refrigerant pipe 66 .

When the outdoor unit 1 starts operating, the blower fan 30 starts rotating before the compressor 5. The rotating blower fan 30 causes air to flow from the outside of the outdoor unit 1 into the inside of the housing 10, i.e., into the blower chamber S2. Specifically, air mainly flows into the blower chamber S2 from the front air intake 15 and the side air intake 17. The air flowing into the blower chamber S2 passes between each of the flat tubes 62 and each of the fins 64 in a direction perpendicular to the longitudinal direction and the up-down direction of the outdoor heat exchanger 50, in other words, along the width direction of the flat tubes 62.

This promotes heat exchange between the refrigerant flowing inside the flat tubes 62 and the air flowing between the fins 64 .
The air that has exchanged heat with the refrigerant is exhausted by the blower fan 30 from the exhaust port 19 to the outside of the housing 10 .

By repeating the above-mentioned operation, the outdoor unit 1 absorbs heat from the outdoor air into the refrigeration circuit and sends it out into the room.
When the air conditioner performs cooling operation, the refrigerant circulates in the refrigeration circuit in the opposite direction to that in heating operation, and the outdoor heat exchanger 50 functions as a condenser.

As described above, in the header pipe 52, the internal space SP is partitioned into the first space SP1 and the second space SP2 by the partition plate 80. This reduces the flow path cross-sectional area of the header pipe 52.
When the outdoor heat exchanger 50 functions as an evaporator, the gas-liquid two-phase refrigerant flows into the header pipe 52 via the second refrigerant piping 68. In the header pipe 52, the gas-liquid two-phase refrigerant flowing through the second refrigerant piping 68 flows into the first space SP1. As described above, in the first space SP1 in which the flow path cross-sectional area is reduced, a reduction in the flow velocity of the gas-liquid two-phase refrigerant is suppressed.

As a result, the gas-liquid two-phase refrigerant rises to the top of the header pipe 52, and in the process of rising, it flows from the first space SP1 into the second space SP2 through multiple communication holes 81 provided in the partition plate 80. The refrigerant then flows into the flat tubes 62 located near each of the communication holes 81 while maintaining its flow velocity.

In this way, in the outdoor heat exchanger 50, the reduction in refrigerant flow velocity is suppressed in the first space SP1 of the header pipe 52, and the gas-liquid two-phase refrigerant is uniformly distributed in the vertical direction of the second space SP2 through the multiple communication holes 81 with the gas-liquid state being homogenized. As a result, in the outdoor heat exchanger 50, drift caused by the vertical arrangement position of the flat tubes 62 is suppressed. And, in the outdoor heat exchanger 50, uneven distribution of refrigerant to each of the flat tubes 62 is suppressed, improving heat exchange performance.

As described above, the communication hole 81 is provided in the width direction of the flat tube 62 at a position overlapping with the end portion located upstream in the air flow direction generated by the blower fan 30 when viewed from the direction in which the flat tube 62 extends.
As a result, the gas-liquid two-phase refrigerant uniformly distributed in the vertical direction in the second space SP2 of the header pipe 52 can easily flow into the refrigerant flow path located upstream of the air flow in the flat tubes 62 and easily exchange heat with the air. Therefore, in the outdoor heat exchanger 50, even when the air conditioning apparatus performs partial load operation with a small amount of refrigerant circulating, a larger amount of refrigerant can exchange heat with air with a large temperature difference, thereby improving heat exchange performance.

6 is a cross-sectional view that typically shows the internal structure of the outdoor heat exchanger 50. In FIG. 6, a cross-section of the outdoor heat exchanger 50 taken along a plane that is parallel to the bottom surface of the header pipe 52 and passes through the communication hole 81 is shown.
As described above, the partition plate 80 is provided in a position in the internal space SP closer to the connection side surface 59 than to the connection side surface 55. As shown in Fig. 6, of the gas-liquid two-phase refrigerant that has flowed into the first space SP1 of the header pipe 52, the liquid refrigerant is likely to be maintained in the space near the end where the inner wall of the header pipe 52 and the partition plate 80 contact each other due to surface tension.

In contrast, of the gas-liquid two-phase refrigerant that flows into the first space SP1 of the header pipe 52, the reduction in the flow path cross-sectional area of the first space SP1 suppresses a decrease in the refrigerant flow rate. Therefore, in the first space SP1, the gas refrigerant rises to the top of the header pipe 52 while dragging in the liquid refrigerant on the wall surface. In this rising process, the gas-liquid two-phase refrigerant flows into the second space SP2 through multiple communication holes 81 provided in the partition plate 80.

In this way, in the outdoor heat exchanger 50, liquid refrigerant is maintained in the space near the end where the inner wall of the header pipe 52 meets the partition plate 80, and phase separation of the gas-liquid two-phase refrigerant due to gravity is suppressed in the vertical direction of the header pipe 52. Furthermore, the gas refrigerant rises to the top of the header pipe 52 while suppressing a decrease in flow rate as it entrains liquid refrigerant on the wall surface, suppressing flow deviation due to the arrangement position of the flat tubes 62. Therefore, in the outdoor heat exchanger 50, uneven distribution of the refrigerant to the multiple flat tubes 62 is suppressed, improving heat exchange performance.

Next, an experiment for measuring the performance of the heat exchanger according to this embodiment will be described.
Fig. 7 is a diagram showing the performance of heat exchangers 100 and 150 provided with a partition plate 80, and a heat exchanger 200 in which the partition plate 80 is omitted. In Fig. 7, the vertical axis represents the heating capacity Y [W], and the horizontal axis represents the refrigerant circulation amount X [kg/h].
7, P1 is the heating performance of the heat exchangers 100, 150, and 200 during minimum operation, P2 is the heating performance of the heat exchangers 100, 150, and 200 during rated operation, and P3 is the heating performance of the heat exchangers 100, 150, and 200 during intermediate operation between the minimum operation and the rated operation.

The inventors verified the effect of the partition plate 80 on the performance of the outdoor heat exchanger 50 of this embodiment through simulations using heat exchangers 100 and 150 provided with a partition plate 80 as in this embodiment, and a heat exchanger 200 not provided with a partition plate 80.

The partition plate 80 provided in the heat exchanger 100 has a plurality of rectangular communication holes 81. The length dimension of these communication holes 81 in a direction perpendicular to the longitudinal direction of the partition plate 80 is approximately the same as the length dimension in the width direction of the flat tubes 62. Furthermore, the length dimension of these communication holes 81 in the longitudinal direction of the partition plate 80 is longer than the length dimension in the plate thickness direction of the flat tubes 62. The total area of the communication holes 81 provided in the partition plate 80 is 655.6 mm2.

The partition plate 80 provided in the heat exchanger 150 has a plurality of circular communication holes 81 that are smaller than the communication holes 81 provided in the heat exchanger 100. The length dimension of these communication holes 81 along a direction perpendicular to the longitudinal direction of the partition plate 80 is shorter than the dimension in the width direction of the flat tubes 62. Furthermore, the length dimension of these communication holes 81 along the longitudinal direction of the partition plate 80 is longer than the length dimension in the plate thickness direction of the flat tubes 62. Furthermore, the partition plate 80 provided in the heat exchanger 150 has a greater number of communication holes 81 than the communication holes 81 of the partition plate 80 provided in the heat exchanger 100. The total area of the communication holes 81 provided in the partition plate 80 is 190.9 mm2.

The inventors then investigated the performance characteristics of the heat exchangers 100, 150, and 200 with respect to the amount of refrigerant circulating. Specifically, the inventors investigated the performance characteristics of the heat exchangers 100, 150, and 200 during minimum operation, when the amount of refrigerant circulating is at a minimum, during rated operation, when the amount of refrigerant circulating is at a maximum, and during intermediate operation, when the amount of refrigerant circulating is intermediate between minimum operation and rated operation, in an air conditioning system performing heating operation.

As a result, as shown in FIG. 7, the heat exchangers 100 and 150 provided with the partition plate 80 exhibited higher capacity values than the heat exchanger 200 not provided with the partition plate 80 at any refrigerant circulation rate.
Furthermore, between the heat exchanger 100 and the heat exchanger 150, the heat exchanger 100 exhibited a higher capacity value.

From these results, the inventors have found that the performance of the outdoor heat exchanger 50 is improved by providing the partition plate 80 .
The inventors also found that the performance of the outdoor heat exchanger 50 changes depending on the number, total area, and arrangement position of the communication holes 81, regardless of the shape of the communication holes 81. That is, the inventors found that a larger total area of the communication holes 81 increases the flow path area of the refrigerant and reduces flow path pressure loss, making it easier for the refrigerant to flow from each communication hole 81 to the flat tubes 62, thereby improving heat exchange performance.

[1-3. Effects, etc.]
As described above, in this embodiment, the outdoor heat exchanger 50 includes a plurality of flat tubes 62 arranged at a predetermined interval in the vertical direction of the header pipe 52, and a plurality of header pipes 52 to which both ends of each flat tube 62 are connected. When the outdoor heat exchanger 50 functions as an evaporator, a second refrigerant pipe 68 that supplies a gas-liquid two-phase refrigerant is connected to at least one lower part of the header pipe 52. Inside the header pipe 52 to which the second refrigerant pipe 68 is connected, a partition plate 80 is provided that extends in the vertical direction and partitions the first space SP1 that communicates with the second refrigerant pipe 68 and the second space SP2 that communicates with the flat tube 62. The partition plate 80 is provided with a plurality of communication holes 81 that communicate between the first space SP1 and the second space SP2 above the connection position of the second refrigerant pipe 68.

As a result, in the first space SP1, a reduction in the flow rate of the two-phase gas-liquid refrigerant is suppressed, and the two-phase gas-liquid refrigerant rises to the top of the header pipe 52, and in the process of rising, flows from the first space SP1 into the second space SP2 through the multiple communication holes 81 provided in the partition plate 80. Therefore, in the outdoor heat exchanger 50, with the gas-liquid state being homogenized, the two-phase gas-liquid refrigerant is evenly distributed in the vertical direction of the second space SP2 through the multiple communication holes 81, and drift due to the vertical arrangement position of the flat tubes 62 is suppressed. And, in the outdoor heat exchanger 50, uneven distribution of the refrigerant to each of the flat tubes 62 is suppressed, improving heat exchange performance.

As in the present embodiment, in the outdoor heat exchanger 50 , air may flow along the width direction of the flat tubes 62 , and the communication holes 81 may be provided on the upstream side of the air flow of the flat tubes 62 .
As a result, the gas-liquid two-phase refrigerant uniformly distributed in the vertical direction in the second space SP2 of the header pipe 52 can easily flow into the refrigerant flow path located upstream of the air flow in the flat tubes 62 and easily exchange heat with the air. Therefore, in the outdoor heat exchanger 50, even when the air conditioning apparatus performs partial load operation with a small amount of refrigerant circulating, a larger amount of refrigerant can exchange heat with air with a large temperature difference, thereby improving heat exchange performance.

As in this embodiment, the partition plate 80 may be provided closer to the wall surface of the header pipe 52 on the side to which the flat tubes 62 are connected than to the wall surface of the header pipe 52 on the side to which the connecting pipes are connected.
As a result, in the outdoor heat exchanger 50, liquid refrigerant is maintained in the space near the end where the inner wall of the header pipe 52 and the partition plate 80 come into contact, and phase separation of the gas-liquid two-phase refrigerant due to the effect of gravity is suppressed in the vertical direction of the header pipe 52. Furthermore, the gaseous refrigerant rises to the upper part of the header pipe 52 while suppressing a decrease in flow velocity, while entraining the liquid refrigerant on the wall surface, and suppresses drift in flow due to the arrangement position of the flat tubes 62. As a result, in the outdoor heat exchanger 50, uneven distribution of the refrigerant to the multiple flat tubes 62 is suppressed, and heat exchange performance can be improved.

Other Embodiments
As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first embodiment to create a new embodiment.
Therefore, other embodiments will be exemplified below.

FIG. 8 is a vertical cross-sectional view that typically shows the internal structure of the outdoor heat exchanger 50 according to the first modified example.
As shown in FIG. 8 , in the outdoor heat exchanger 50 of the first modified example, the partition plate 180 is provided so as to be inclined from the lower portion to the upper portion so as to approach the connection side surface 55 from the connection side surface 59 .

As a result, the gas-liquid two-phase refrigerant that flows into the first space SP1 of the header pipe 52 via the second refrigerant piping 68 rises in the first space SP1 along the inclined surface of the partition plate 180. As the gas-liquid two-phase refrigerant rises, it flows into the second space SP2 through the multiple communication holes 81 provided in the partition plate 180, and flows into the flat tubes 62 near the communication holes 81 while suppressing a decrease in flow rate.

As a result, the gas-liquid two-phase refrigerant flowing in from the second refrigerant piping 68 is prevented from flowing vertically into the partition plate 180 in the header pipe, and a decrease in refrigerant flow speed and gas-liquid separation due to collision with the partition plate 180 are suppressed. In particular, even when the air conditioning system is operating under overload with a large refrigerant circulation volume and a high refrigerant flow speed, the outdoor heat exchanger 50 can equalize the gas-liquid state of the refrigerant in the first space SP1 and send the refrigerant to the top of the header pipe 52, suppressing drift due to the vertical arrangement position of the flat tubes 62. As a result, the outdoor heat exchanger 50 is prevented from being unevenly distributed to the multiple flat tubes 62, improving heat exchange performance.

FIG. 9 is a diagram showing a partition plate 280 according to the second modification.
As shown in FIG. 9 , in the outdoor heat exchanger 50 of the second modification, a partition plate 280 is provided.
The partition plate 280 has communication holes 81 at positions in the width direction of the flat tubes 62 that overlap both ends of the flat tubes 62 when viewed in the longitudinal direction of the flat tubes 62 .

FIG. 10 is a cross-sectional view that illustrates a schematic internal structure of the outdoor heat exchanger 50 according to the second modification.
10, in the first space SP1, liquid refrigerant is maintained by surface tension in the space near where the inner wall of the header pipe 52 contacts the partition plate 280. In the process of rising together with the gaseous refrigerant in the first space SP1, the liquid refrigerant flows into the second space SP2 from the communication hole 81 provided at a position approaching the space near where the inner wall of the header pipe 52 contacts the partition plate 280, and flows into the flat tubes 62 near the communication hole 81 while a decrease in flow rate is suppressed.

In the first space SP1, the liquid refrigerant held in the space near where the inner wall of the header pipe 52 meets the partition plate 280 can easily flow into the second space SP2 from the communication holes 81. As a result, even during partial load operation when the amount of refrigerant circulating is small, the refrigerant can be evenly distributed in the vertical direction of the second space SP2, and drift caused by the arrangement position of the flat tubes 62 in the vertical direction is suppressed. As a result, in the outdoor heat exchanger 50, uneven distribution to the multiple flat tubes 62 is suppressed, improving heat exchange performance.

In the embodiment described above, the outdoor heat exchanger 50 is provided with a connected header pipe 54. However, this is not limited, and the outdoor heat exchanger 50 may be provided with a header pipe that is substantially the same as the header pipe 52. This header pipe is connected to the other end of each of the flat tubes 62 extending from one header pipe 52. When two header pipes 52 are provided as in the present embodiment, each header pipe 52 is connected to the corresponding header pipe via a plurality of flat tubes 62. These header pipes are connected to each other, for example, by piping through which a refrigerant flows.

In the above-described embodiment, two flat tubes 62 are arranged along the width direction of the flat tube 62, but this is not limited thereto, and for example, three or more may be arranged.

The above-described embodiments are intended to illustrate the technology disclosed herein, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

(Additional Note)
The above description of the embodiments discloses the following techniques.

(Technology 1) A heat exchanger including a plurality of flat tubes arranged at a predetermined interval in the vertical direction of a header pipe, and a plurality of the header pipes to which both ends of each of the flat tubes are connected, wherein, when the heat exchanger functions as an evaporator, a connecting pipe for supplying a gas-liquid two-phase refrigerant is connected to the lower part of at least one of the header pipes, and a partition plate is provided inside the header pipe to which the connecting pipe is connected, dividing the header pipe into a first space extending in the vertical direction and communicating with the connecting pipe, and a second space communicating with the flat tubes, and the partition plate is provided with a plurality of communication holes communicating between the first space and the second space above the connection position of the connecting pipe.
With this configuration, the reduction in the flow rate of the gas-liquid two-phase refrigerant is suppressed in the first space, and the gas-liquid two-phase refrigerant rises to the top of the header pipe and flows from the first space to the second space through the multiple communication holes provided in the partition plate during the rising process. Therefore, in the heat exchanger, uneven distribution of the refrigerant to each of the flat tubes is suppressed, and the heat exchange performance can be improved.

(Technology 2) A heat exchanger according to Technology 1, in which air flows along a width direction of the flat tubes, and the communication holes are provided upstream of the air flow of the flat tubes.
With this configuration, the gas-liquid two-phase refrigerant can easily flow into the refrigerant flow path located upstream of the air flow in the flat tubes and easily exchange heat with the air. Therefore, even when the air conditioner is operating at a partial load with a small amount of refrigerant circulating, the heat exchanger can exchange heat with more refrigerant and air with a large temperature difference, improving heat exchange performance.

(Technology 3) A heat exchanger described in Technology 1 or Technology 2, in which the partition plate is inclined from the bottom to the top so as to approach from the lower wall surface of the header pipe on the side where the connecting pipe is connected to the wall surface of the header pipe on the side where the flat tubes are connected.
With this configuration, the gas-liquid two-phase refrigerant that flows into the first space of the header pipe through the connecting pipe rises in the first space along the inclined surface of the partition plate while suppressing a decrease in flow velocity, and flows into the second space through the multiple communication holes. Therefore, the gas-liquid two-phase refrigerant that flows in from the connecting pipe is prevented from flowing perpendicularly to the partition plate in the header pipe, and a decrease in refrigerant flow velocity and gas-liquid separation due to collision with the partition plate are suppressed.

(Technology 4) A heat exchanger described in any one of Technologies 1 to 3, wherein the partition plate is arranged closer to the wall surface of the header pipe on the side to which the flat tubes are connected than to the wall surface of the header pipe on the side to which the connecting pipe is connected.
With this configuration, in the heat exchanger, liquid refrigerant is maintained in the space near the end where the inner wall of the header pipe and the partition plate come into contact, and phase separation of the gas-liquid two-phase refrigerant due to gravity in the vertical direction of the header pipe is suppressed. Therefore, in the heat exchanger, uneven distribution of the refrigerant among the multiple flat tubes is suppressed, and heat exchange performance can be improved.

(Technology 5) A heat exchanger according to any one of Technology 1 to Technology 4, wherein the communication holes are provided at positions overlapping both ends of the flat tubes in the width direction.
With this configuration, the liquid refrigerant held in the first space near where the inner wall of the header pipe and the partition plate meet can easily flow into the second space through the communication holes, which prevents the liquid refrigerant from being unevenly distributed among the flat tubes in the heat exchanger, thereby improving the heat exchange performance.

(Technical 6) An outdoor unit comprising the heat exchanger according to any one of Technical 1 to Technical 5.
With this configuration, the outdoor unit achieves the same effects as the heat exchanger described above.

This disclosure is applicable to heat exchangers that include flat tubes and a header pipe. Specifically, this disclosure is applicable to heat exchangers that are installed in outdoor units.

REFERENCE SIGNS LIST 1 Outdoor unit 5 Compressor 10 Housing 30 Blower fan 50 Outdoor heat exchanger 51, 53 Side surface 52 Header pipe 54 Connecting header pipe 55, 57, 59 Connection side surface 62 Flat tube 64 Fin 66 First refrigerant piping 68 Second refrigerant piping (connecting pipe)
80, 180, 280 Partition plate 81 Communication hole 100, 150, 200 Heat exchanger S Internal space S1 Machine room S2 Blower room SP, SQ Internal space SP1 First space (first space)
SP2 Second space (second space)
X Refrigerant circulation volume Y Heating capacity

Claims (6)

1. A heat exchanger including a plurality of flat tubes arranged at predetermined intervals in the vertical direction of a header pipe, and a plurality of the header pipes to which both ends of each of the flat tubes are connected,
   When the heat exchanger functions as an evaporator,
   A connection pipe for supplying a gas-liquid two-phase refrigerant is connected to a lower portion of at least one of the header pipes,
   A partition plate is provided inside the header pipe to which the connecting pipe is connected, and divides the header pipe into a first space extending in a vertical direction and communicating with the connecting pipe and a second space communicating with the flat tubes,
   the partition plate is provided with a plurality of communication holes above a connection position of the connecting pipe, the communication holes connecting the first space and the second space.
2. Air flows along the width direction of the flat tube,
   The heat exchanger according to claim 1 , wherein the communication hole is provided on an upstream side of the flat tube in the air flow direction.
3. 3. The heat exchanger according to claim 1, wherein the partition plate is inclined from the bottom to the top so as to approach a wall surface of the header pipe on a side where the flat tubes are connected, from a lower wall surface of the header pipe on a side where the connecting pipe is connected.
4. 3. The heat exchanger according to claim 1, wherein the partition plate is provided closer to a wall surface of the header pipe on a side to which the flat tubes are connected than to a wall surface of the header pipe on a side to which the connecting pipes are connected.
5. The heat exchanger according to claim 1 or 2, wherein the communication holes are provided at positions overlapping both ends in a width direction of the flat tubes.
6. An outdoor unit comprising the heat exchanger according to claim 1 or 2.

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