WO2021234957A1

WO2021234957A1 - Heat exchanger and air conditioner comprising said heat exchanger

Info

Publication number: WO2021234957A1
Application number: PCT/JP2020/020350
Authority: WO
Inventors: 直渡原; 哲二七種
Original assignee: 三菱電機株式会社
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2021-11-25
Also published as: JPWO2021234957A1; US20230095279A1; JP7353483B2; EP4155645A1; EP4155645A4

Abstract

In the present invention, a heat exchanger comprises: a plurality of flat tubes positioned in parallel and spaced apart from each other, a refrigerant channel flowing in the vertical direction being formed by the plurality of flat tubes; a plurality of fins provided between adjacent flat tubes; an upper header to which the respective upper end parts of the plurality of flat tubes are connected; and a lower header to which are connected the respective upper end parts of the plurality of flat tubes. The respective lower end parts of the fins are not joined to the lower header; a lower gap is provided between the lower header and the respective lower end parts of the fins.

Description

A heat exchanger and an air conditioner equipped with the heat exchanger

The present disclosure relates to a heat exchanger having a plurality of flat tubes and fins provided between adjacent flat tubes, and an air conditioner provided with the heat exchanger.

Conventionally, a heat exchanger having a plurality of heat transfer tubes in which a refrigerant flow path is formed and a plurality of fins provided between adjacent heat transfer tubes is known. For example, the heat exchanger disclosed in Patent Document 1 has a pair of vertically extending headers arranged at intervals in the left-right direction and a pair of headers arranged at intervals in the up-down direction, and the left and right ends are respectively arranged. It is configured to have a flat refrigerant flow pipe connected to a header and corrugated fins arranged between adjacent refrigerant flow pipes.

Japanese Patent No. 4423906

The heat exchanger disclosed in Patent Document 1 is affected by the weight when distributing the refrigerant to the refrigerant flow pipes through the header, so that the refrigerant flowing into each refrigerant flow pipe becomes non-uniform. For example, during the heating operation, the refrigerant tends to flow to the lower part where the wind speed is low, and the amount of the refrigerant to the upper part where the wind speed is high is small, so that efficient heat exchange may not be possible. For such improvement of the refrigerant distribution, for example, there is a method using a capillary tube. However, in this case, it is necessary to adjust the refrigerant distribution with a plurality of capillary tubes having different diameters and lengths so that the refrigerant is distributed to each refrigerant flow rate so that the flow rate is appropriate, which may increase the cost. be.

Therefore, in order to solve the above problem, a refrigerant flow path that flows in the vertical direction is formed, and a plurality of flat pipes arranged in parallel at intervals from each other and a plurality of fins provided between adjacent flat pipes. A heat exchanger has been developed with an upper header to which the upper ends of each of the plurality of flat tubes are connected, and a lower header to which the upper ends of each of the plurality of flat tubes are connected. However, in this heat exchanger, moisture in the air may condense on the surface of the fin, and the condensed water may flow down to the lower part of the fin along the fin, and water droplets may stay at the lower end of the fin. Water accumulated at the lower end of the fin may freeze when the outside air is below freezing and damage the heat exchanger. Therefore, it is necessary to drain the water droplets flowing down the fin along the fin to the outside without staying at the lower end portion of the fin.

The present disclosure has been made in order to solve the above-mentioned problems, and in a structure in which fins are provided between a plurality of flat pipes in which a plurality of refrigerant flow paths are formed in the vertical direction, the lower end portion of the fins is provided. It is an object of the present invention to provide a heat exchanger and an air conditioner equipped with the heat exchanger, which can suppress the situation where water droplets stay in the water.

In the heat exchanger according to the present disclosure, a plurality of flat pipes in which a refrigerant flow path flowing in the vertical direction is formed and arranged in parallel at intervals from each other, and a plurality of fins provided between the adjacent flat pipes. And an upper header to which the upper end of each of the plurality of flat tubes is connected, and a lower header to which the upper ends of each of the plurality of flat tubes are connected, and the lower end of each of the fins is the lower portion. It is not joined to the header, and a lower gap is provided between the lower end of each fin and the lower header.

The air conditioner according to the present disclosure is equipped with the above heat exchanger.

According to the heat exchanger of the present disclosure and the air conditioner provided with the heat exchanger, the lower end portion of each fin is not joined to the lower header, and the lower end portion of each fin is used for drainage between the lower end portion and the lower header. Since the lower gap is provided, water droplets can be dropped below the fin through the lower gap to drain the water, and the situation where the water droplets stay at the lower end of the fin can be suppressed.

It is a refrigerant circuit diagram of the air conditioner which concerns on Embodiment 1. It is a perspective view which showed the appearance of the outdoor unit of the air conditioner which concerns on Embodiment 1. It is a front view which showed schematicly about the heat exchanger which concerns on Embodiment 1. FIG. 3 is a perspective view of the cross section of the IV portion shown in FIG. 3 as viewed from above. It is a front view which showed schematicly about the heat exchanger which concerns on embodiment 2.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be omitted or simplified as appropriate. In addition, the shape, size, arrangement, and the like of the configurations shown in each figure can be appropriately changed.

Embodiment 1.
FIG. 1 is a refrigerant circuit diagram of the air conditioner according to the first embodiment. As shown in FIG. 1, the outdoor unit 100 of the air conditioner 300 according to the first embodiment constitutes the air conditioner 300 together with the indoor unit 200 that air-conditions the room. The air conditioner 300 connects the compressor 101, the flow path switching means 102, the indoor heat exchanger 201, the expansion mechanism 103, and the outdoor heat exchanger 104 with a refrigerant pipe 105 to circulate the refrigerant. It has a circuit. The outdoor unit 100 includes a compressor 101, a flow path switching means 102, an expansion mechanism 103, and an outdoor heat exchanger 104. The indoor unit 200 includes an indoor heat exchanger 201. The air conditioner 300 is not limited to the illustrated components, and may include other components.

The compressor 101 compresses the sucked refrigerant and discharges it in a high temperature and high pressure state. As an example, the compressor 101 is a positive displacement compressor having a configuration in which the operating capacity (frequency) can be changed and is driven by a motor controlled by an inverter.

The flow path switching means 102 is a four-way valve as an example, and has a function of switching the flow path of the refrigerant. The flow path switching means 102 connects the refrigerant discharge side of the compressor 101 and the gas side of the outdoor heat exchanger 104 during the cooling operation, and also connects the refrigerant suction side of the compressor 101 and the gas side of the indoor heat exchanger 201. Switch the refrigerant flow path so as to connect with. On the other hand, the flow path switching means 102 connects the refrigerant discharge side of the compressor 101 and the gas side of the indoor heat exchanger 201 during the heating operation, and connects the refrigerant suction side of the compressor 101 and the outdoor heat exchanger 104. Switch the refrigerant flow path so as to connect to the gas side. The flow path switching means 102 may be configured by combining a two-way valve or a three-way valve.

The indoor heat exchanger 201 functions as an evaporator during the cooling operation, and causes heat exchange between the refrigerant flowing out from the expansion mechanism 103 and the air. Further, the indoor heat exchanger 201 functions as a condenser during the heating operation, and causes heat exchange between the refrigerant discharged from the compressor 101 and the air. The indoor heat exchanger 201 sucks indoor air by an indoor blower and supplies the air that has exchanged heat with the refrigerant into the room.

The expansion mechanism 103 decompresses and expands the refrigerant flowing in the refrigerant circuit, and is composed of an electronic expansion valve whose opening degree is variably controlled as an example.

The outdoor heat exchanger 104 functions as a condenser during the cooling operation, and causes heat exchange between the refrigerant discharged from the compressor 101 and the air. Further, the outdoor heat exchanger 104 functions as an evaporator during the heating operation, and causes heat exchange between the refrigerant flowing out from the expansion mechanism 103 and the air. The outdoor heat exchanger 104 sucks in the outdoor air by the outdoor blower and discharges the air that has exchanged heat with the refrigerant to the outside.

Next, the operation of the air conditioner 300 during the cooling operation will be described. The high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching means 102, flows to the outdoor heat exchanger 104, and exchanges heat with air to form a condensed liquid. The condensed liquefied refrigerant is decompressed by the expansion mechanism 103 to become a low-pressure gas-liquid two-phase refrigerant, which flows to the indoor heat exchanger 201 and exchanges heat with air to be gasified. The gasified refrigerant passes through the flow path switching means 102 and is sucked into the compressor 101.

Next, the operation of the air conditioner 300 during the heating operation will be described. The high-temperature and high-pressure gas refrigerant discharged from the compressor 101 passes through the flow path switching means 102, flows to the indoor heat exchanger 201, exchanges heat with air, and becomes a condensed liquid. The condensed liquefied refrigerant is decompressed by the expansion mechanism 103 to become a low-pressure gas-liquid two-phase refrigerant, which flows to the outdoor heat exchanger 104 and exchanges heat with air to be gasified. The gasified refrigerant passes through the flow path switching means 102 and is sucked into the compressor 101.

Next, the structure of the outdoor unit 100 of the air conditioner 300 according to the first embodiment will be described with reference to FIG. FIG. 2 is a perspective view showing the appearance of the outdoor unit of the air conditioner according to the first embodiment. As shown in FIG. 2, the outdoor unit 100 of the air conditioner 300 is a top-flow type outdoor unit in which an air outlet 54 is formed on the upper surface of the housing 5 and an outdoor blower is provided directly below the air outlet 54. It is an opportunity. The outdoor unit 100 of the air conditioner 300 includes, for example, a compressor 101, a flow path switching means 102, an expansion mechanism 103, an outdoor heat exchanger 104, an outdoor blower, a control device, and the like inside the housing 5 forming the outer shell. It is a configuration in which members are stored.

The housing 5 includes a bottom plate 50 provided on the bottom surface and a frame material 51 extending upward from the corners of the bottom plate 50. The housing 5 has a rectangular shape in a plan view and has openings on four side surfaces surrounded by a frame material 51 arranged at the corners. The upper part of the opening is an air suction port 53 for taking in air inside the housing 5, and an outdoor heat exchanger 104 is arranged along each air suction port 53. The lower part of the opening is closed with a side panel 52 which is a design sheet metal. The left and right side edges of the side panel 52 are fixed to the frame material 51 with fastening members such as screws, and the lower edge portion is fixed to the bottom plate 50 with fastening members such as screws. By removing the side panel 52 and opening the inside of the outdoor unit 100, maintenance of the constituent members arranged inside can be performed.

An air outlet 54 is formed on the upper surface of the housing 5, and an outdoor blower is installed at a position directly below the air outlet 54. The air outlet 54 is provided with a bell mouth 55 that surrounds the outdoor blower. Further, a fan guard 54a is attached to the air outlet 54. The outdoor blower is composed of, for example, a propeller fan or the like, and is driven by a blower motor. By driving the outdoor blower, the air sucked into the housing 5 from the air suction port 53 passes through the outdoor heat exchanger 104, exchanges heat with the refrigerant, and then is exhausted from the air outlet 54 via the outdoor blower.

Next, the features of the heat exchanger according to the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a front view schematically showing the heat exchanger according to the first embodiment. FIG. 4 is a perspective view of the cross section of the IV portion shown in FIG. 3 as viewed from above.

The heat exchanger according to the first embodiment is used as the outdoor heat exchanger 104. In the outdoor heat exchanger 104, as shown in FIGS. 3 and 4, a plurality of flat pipes 1 in which a refrigerant flow path 10 flowing in the vertical direction Y is formed and arranged in parallel at intervals from each other and adjacent flat pipes 1 are formed. A plurality of fins 2 provided between the tubes 1, an upper header 3 to which the upper end portions of the plurality of flat tubes 1 are connected, and a lower header 4 to which the lower end portions of the plurality of flat tubes 1 are connected to each other. And have.

The flat tube 1 is made of, for example, aluminum. The flat tubes 1 are arranged in parallel at intervals in the left-right direction X so as to be orthogonal to the flow direction Z of the air flow. Further, the flat tube 1 is arranged so that the flow direction Z of the air flow and the flat surface are substantially parallel to each other. Inside the flat tube 1, a plurality of refrigerant flow paths 10 through which the refrigerant flows in the vertical direction Y are formed in parallel along the flow direction Z of the air flow. The vertical direction Y includes not only the vertical direction but also a state of being tilted with respect to the vertical direction. Further, the left-right direction X includes not only the horizontal direction but also a state of being tilted with respect to the horizontal direction.

The fin 2 is made of aluminum, for example, and is a member that transfers the heat of the refrigerant flowing through the flat tube 1. The fin 2 is a corrugated fin formed by bending a thin plate in a wavy shape. The fins 2 are provided between two flat tubes 1 adjacent to each other among the plurality of flat tubes 1. The bent apex of the fin 2 is joined to the flat surface of either of the two flat tubes 1. The space between the fin 2 and the flat tube 1 is a ventilation path through which air flows. Although not shown, the fin 2 may be configured to have a drain hole, a louver, or the like for draining condensed water on each slope. Further, the fin 2 is not limited to the corrugated fin, and may be, for example, plate fins arranged in parallel along the vertical direction.

The upper header 3 is connected to the upper ends of each of the plurality of flat pipes 1 and is connected to the flow path switching means 102 via the refrigerant pipe 105. The upper header 3 is made of, for example, aluminum. The upper header 3 distributes the gas refrigerant flowing from the refrigerant pipe 105 to each flat pipe 1 when the outdoor heat exchanger 104 acts as a condenser. Further, the upper header 3 causes the gas refrigerant merged from the flat pipe 1 to flow out to the refrigerant pipe 105 when the outdoor heat exchanger 104 acts as an evaporator.

The lower header 4 is connected to the lower ends of each of the plurality of flat pipes 1 and is connected to the expansion mechanism 103 via the refrigerant pipe 105. The lower header 4 is made of, for example, aluminum. The lower header 4 causes the liquid refrigerant merged from the flat pipe 1 to flow out to the refrigerant pipe 105 when the outdoor heat exchanger 104 acts as a condenser. Further, the lower header 4 distributes the gas-liquid two-phase refrigerant flowing from the refrigerant pipe 105 to each flat pipe 1 when the outdoor heat exchanger 104 acts as an evaporator.

By the way, when the outdoor heat exchanger 104 is used as an evaporator, the evaporation temperature of the refrigerant is lower than the ambient air temperature, so that the moisture in the air condenses on the surface of the fin 2, and the condensed water is condensed. It may flow down along the fin 2 and stay at the lower end of the fin 2. Further, in the outdoor heat exchanger 104, a defrosting operation may be performed in order to remove the frost adhering to the fin 2 and the flat tube 1. Water droplets that have been thawed by this defrosting operation and adhered to the fin 2 and the flat tube 1 may flow down the lower part of the fin 2 and stay at the lower end portion of the fin 2. The water accumulated in the lower part of the fin 2 may freeze when the outside air becomes below the freezing point and damage the outdoor heat exchanger 104. Therefore, it is necessary to drain the water droplets flowing down the fin 2 to the outside without staying in the lower part of the fin 2.

Further, in the outdoor heat exchanger 104, the upper ends of the plurality of flat tubes 1 are connected to the upper header 3, and the lower ends of the plurality of flat tubes 1 are connected to the lower header 4. The joining of the flat tube 1 to the upper header 3 and the lower header 4 is performed, for example, by brazing. Therefore, it is necessary to secure a space for brazing and joining the flat tube 1, the upper header 3 and the lower header 4.

Therefore, in the heat exchanger 104 according to the first embodiment, as shown in FIG. 3, the lower end portion of each fin 2 is not joined to the lower header 4, and the lower portion of each fin 2 and the lower header 4 are connected to each other. A lower gap 6 for drainage is provided between them. By providing the lower gap 6, the outdoor heat exchanger 104 can drop the water droplets that have flowed down to the lower portion of the fin 2 downward without staying at the lower end portion of the fin 2, thus improving the drainage property. Can be done. Further, in the outdoor heat exchanger 104, the lower end portion of the flat tube 1 and the lower header 4 can be brazed and joined by utilizing the lower gap 6. The lower gap 6 is provided with a size in consideration of drainage.

Further, in the heat exchanger 104 according to the first embodiment, the upper end portion of each fin 2 is not joined to the upper header 3, and the flat tube 1 is located between the upper end portion of each fin 2 and the upper header 3. An upper gap 7 is provided for brazing and joining the upper header 3 and the upper header 3. The outdoor heat exchanger 104 can braze and join the upper end portion of the flat tube 1 and the upper header 3 by utilizing the upper gap 7.

The vertical width of the upper gap 7 is smaller than the vertical width of the lower gap 6. The outdoor heat exchanger 104 has a high wind speed in the upper part near the blower and a low wind speed in the lower part away from the blower. The upper part of the outdoor heat exchanger 104 having a high wind speed is the place where the heat exchange efficiency is the highest. In the outdoor heat exchanger 104, if the vertical width of the upper gap 7 is increased, the amount of bypass air that does not exchange heat increases, and the heat exchange efficiency may decrease. Therefore, it is desirable that the upper gap 7 has the minimum size that can be brazed and joined, and the size that can suppress the bypass air volume without heat exchange as much as possible. For example, in the outdoor heat exchanger 104, the wind speed at the upper part may be approximately three times the wind speed at the lower part. Therefore, considering the ratio of the upper wind speed to the lower wind speed, it is conceivable that the upper gap 7 is set to one-third or less of the lower gap 6. It should be noted that this ratio is an example and changes depending on conditions such as the performance of the blower and the size of the outdoor unit.

As described above, in the heat exchanger 104 according to the first embodiment, the refrigerant flow paths 10 are formed in the vertical direction Y, and a plurality of flat pipes arranged in parallel at intervals in the left-right direction X. 1, a plurality of fins 2 provided between adjacent flat tubes 1, an upper header 3 to which the upper ends of each of the plurality of flat tubes 1 are connected, and an upper end of each of the plurality of flat tubes 1. It includes a connected lower header 4. The lower end of each fin 2 is not joined to the lower header 4, and a lower gap 6 is provided between the lower end of each fin 2 and the lower header 4.

Therefore, since the heat exchanger 104 can drain the water droplets flowing to the lower part through the fins 2 to the lower part of the fins 2 through the lower gap 6, the water droplets stay at the lower end portion of the fins 2. Can be suppressed. Further, in this heat exchanger 104, the lower header 4 and the lower end portion of the flat tube 1 can be joined by brazing using the lower gap 6.

Further, in this heat exchanger 104, the upper end portion of each fin 2 is not joined to the upper header 3, and an upper gap 7 is provided between the upper end portion of each fin 2 and the upper header 3. Therefore, in this heat exchanger 104, the upper header 3 and the upper end portion of the flat tube 1 can be joined by brazing using the upper gap 7.

Further, the vertical width dimension of the upper gap 7 is smaller than the vertical width dimension of the lower gap 6. That is, the heat exchanger 104 according to the first embodiment has a structure capable of improving the drainage property in the lower gap 6 and suppressing the bypass air volume that does not exchange heat in the upper gap 7 as much as possible.

Embodiment 2.
Next, the heat exchanger according to the second embodiment will be described with reference to FIG. FIG. 5 is a front view schematically showing the heat exchanger according to the second embodiment. The white arrow shown in FIG. 5 indicates the flow direction Z of the air flow. The same components as those of the heat exchanger described in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

The heat exchanger 104A according to the second embodiment is also used as an outdoor heat exchanger. The outdoor heat exchanger 104 is characterized in that, in addition to the structure of the heat exchanger 104 of the first embodiment, a portion A having a small waveform pitch and a portion B having a large waveform pitch are provided in the fin 2. There is. As described above, the heat exchanger has a high wind speed in the upper part near the blower and a low wind speed in the lower part away from the blower. Therefore, the heat exchanger can improve the heat exchange performance by increasing the heat transfer area in the upper part near the blower. Therefore, in the fin 2 of the outdoor heat exchanger 104A according to the second embodiment, a portion A having a small waveform pitch is provided in the upper portion where the wind speed is large, and a portion B having a large waveform pitch is provided in the lower portion where the wind speed is small. It is supposed to be.

Specifically, the fin 2 is divided into two regions in the vertical direction Y, and the upper half is a portion A having a small waveform pitch and the lower half is a portion B having a large waveform pitch. .. The pitch in the portion A where the pitch of the waveform is small is about one-half to one-third of the pitch of the portion B where the pitch of the waveform is large. The pitch is an example, and shall be appropriately changed and provided according to the size of the outdoor unit, the installation location, and the like.

The arrangement of the portion A in which the pitch of the waveform of the fin 2 is small and the portion B in which the pitch of the waveform of the fin 2 is large is not limited to the illustrated configuration. Although not shown in detail, for example, the fin 2 may be divided into three or more regions in the vertical direction Y, and the pitch of the waveform may be gradually reduced for each region from the lower side to the upper side. Further, the fins 2 may be configured so that the pitch of the waveform becomes smaller from the lower side to the upper side. In short, the portion having a small waveform pitch may be arranged above the portion having a large waveform pitch.

The heat exchanger 104A and the air conditioner 300 provided with the heat exchanger according to the second embodiment have a configuration in which the fins 2 are bent in a wavy shape in the vertical direction Y, and the pitch of the waveform is small. It has A and a portion B having a large waveform pitch. The portion A having a small waveform pitch is arranged above the portion B having a large waveform pitch.

Therefore, the heat exchanger 104A and the air conditioner 300 provided with the heat exchanger according to the second embodiment are provided with a portion A having a small waveform pitch in the upper portion near the blower and having a large wind speed to transmit the fin 2. Since the heat area is increased, the heat exchange performance can be effectively improved.

Although the heat exchanger (104, 104A) and the air conditioner 300 provided with the heat exchanger (104, 104A) have been described above based on the embodiment, the heat exchanger (104, 104A) and the air conditioner have been described above. The machine 300 is not limited to the configuration of the above-described embodiment. Further, for example, the heat exchangers (104, 104A) may be configured to be arranged in two or more rows in the flow direction Z of the air flow. Further, the heat exchangers (104, 104A) and the air conditioner 300 are not limited to the above-mentioned components, and may include other components. In short, the heat exchangers (104, 104A) and the air conditioner 300 include a range of design changes and application variations normally performed by those skilled in the art, to the extent that they do not deviate from their technical ideas.

1 flat tube, 2 fins, 3 upper header, 4 lower header, 5 housing, 6 lower gap, 7 upper gap, 10 refrigerant flow path, 50 bottom plate, 51 frame material, 52 side panel, 53 air suction port, 54 air Outlet, 54a fan guard, 55 bell mouth, 100 outdoor unit, 101 compressor, 102 flow path switching means, 103 expansion mechanism, 104, 104A outdoor heat exchanger, 105 refrigerant piping, 106 components, 200 indoor unit, 201 Indoor heat exchanger, 300 air conditioner.

Claims

A plurality of flat pipes in which a refrigerant flow path flowing in the vertical direction is formed and arranged in parallel at intervals from each other,
A plurality of fins provided between the adjacent flat tubes and
An upper header to which the upper ends of each of the plurality of flat tubes are connected, and
A lower header, to which the upper end of each of the plurality of said flat tubes is connected, is provided.
A heat exchanger in which the lower end of each fin is not joined to the lower header and a lower gap is provided between the lower end of each fin and the lower header.
The heat exchanger according to claim 1, wherein the upper end portion of each of the fins is not joined to the upper header, and an upper gap is provided between the upper end portion of each fin and the upper header.
The heat exchanger according to claim 1 or 2, wherein the upper and lower width dimensions of the upper gap are smaller than the upper and lower width dimensions of the lower gap.
The fin has a structure formed by being bent in a wavy shape in the vertical direction, and has a portion having a small waveform pitch and a portion having a large waveform pitch.
The heat exchanger according to any one of claims 1 to 3, wherein the portion having a small waveform pitch is arranged above the portion having a large waveform pitch.
An air conditioner provided with the heat exchanger according to any one of claims 1 to 4.