JP2019163893A - Heat exchanger and refrigeration cycle device - Google Patents

Abstract

To provide a heat exchanger and a refrigeration cycle device that can enhance heat exchange efficiency by increasing an amount of heat absorbed by a refrigerant.SOLUTION: A heat exchanger according to an embodiment comprises a first header, a second header, and a plurality of heat exchange tubes. The first header and the second header are formed in a cylindrical shape, and arranged separately from each other. The plurality of heat exchange tubes are arranged at intervals in a central axis direction of the first header and the second header, and both end parts are opened inside the first header and the second header. At least one header out of the first header and the second header comprises gas extraction means for extracting a gas refrigerant in an internal space of the header to the outside.SELECTED DRAWING: Figure 5

Description

  Embodiments described herein relate generally to a heat exchanger and a refrigeration cycle apparatus.

  A heat exchanger that performs heat exchange between the refrigerant and the outside air is used. When a heat exchanger is used as the evaporator of the refrigeration cycle apparatus, the refrigerant absorbs heat from outside air. There is a need for a heat exchanger that can improve the heat exchange efficiency by increasing the amount of heat absorbed by the refrigerant.

Japanese Utility Model Publication No. 58-9161

  The problem to be solved by the present invention is to provide a heat exchanger and a refrigeration cycle apparatus capable of improving the heat exchange efficiency by increasing the heat absorption amount of the refrigerant.

  The heat exchanger according to the embodiment includes a first header and a second header, and a plurality of heat exchange tubes. The first header and the second header are formed in a cylindrical shape, and are arranged side by side so as to be separated from each other. The plurality of heat exchange tubes are arranged at intervals in the central axis direction of the first header and the second header, and both ends open to the inside of the first header and the second header. At least one of the first header and the second header has gas extraction means for extracting the gas refrigerant in the internal space of the header out of the header.

The schematic block diagram of the refrigerating-cycle apparatus of 1st Embodiment. The front view of the heat exchanger of 1st Embodiment. The partial perspective view of the heat exchanger of a 1st embodiment. The fragmentary sectional view in the F4-F4 line | wire of FIG. The schematic block diagram of gas extraction piping. The flowchart of the gas extraction method. The schematic block diagram of the refrigerating-cycle apparatus of the modification of 1st Embodiment. The front view of the heat exchanger of 2nd Embodiment.

Hereinafter, the heat exchanger and the refrigeration cycle apparatus of the embodiment will be described with reference to the drawings.
In the present application, the X direction, the Y direction, and the Z direction are defined as follows. The Z direction is the central axis direction (extending direction) of the first header and the second header. For example, the Z direction is a vertical direction, and the + Z direction is an upward direction. The X direction is the central axis direction (extending direction) of the heat exchange tube. For example, the X direction is a horizontal direction, and the + X direction is a direction from the first header to the second header. The Y direction is a direction perpendicular to the X direction and the Z direction.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a refrigeration cycle apparatus according to a first embodiment.
As shown in FIG. 1, the refrigeration cycle apparatus 1 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger (heat exchanger) 4, an expansion device 5, an indoor heat exchanger 6, and a control unit. 9 and. The components of the refrigeration cycle apparatus 1 are sequentially connected by a pipe 7. In each figure, the flow direction of the refrigerant during the heating operation is indicated by a solid line arrow, and the flow direction of the refrigerant during the cooling operation is indicated by a broken line arrow.

  The compressor 2 has a compressor body 2A and an accumulator 2B. The compressor main body 2A compresses the low-pressure gas refrigerant taken into the inside into a high-temperature / high-pressure gas refrigerant. The accumulator 2B separates the gas-liquid two-phase refrigerant and supplies the gas refrigerant to the compressor body 2A.

  The four-way valve 3 reverses the refrigerant flow direction and switches between the heating operation and the cooling operation. During the heating operation, the refrigerant flows in the order of the compressor 2, the four-way valve 3, the indoor heat exchanger 6, the expansion device 5, and the outdoor heat exchanger 4. At this time, the refrigeration cycle apparatus 1 causes the indoor heat exchanger 6 to function as a condenser, causes the outdoor heat exchanger 4 to function as an evaporator, and heats the room. During the cooling operation, the refrigerant flows in the order of the compressor 2, the four-way valve 3, the outdoor heat exchanger 4, the expansion device 5, and the indoor heat exchanger 6. At this time, the refrigeration cycle apparatus 1 causes the outdoor heat exchanger 4 to function as a condenser, causes the indoor heat exchanger 6 to function as an evaporator, and cools the room.

The condenser converts the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 2 to the outside air and condenses it into a high-pressure liquid refrigerant. The evaporator converts the low-temperature and low-pressure liquid refrigerant sent from the expansion device 5 into a low-pressure gas refrigerant by absorbing heat from outside air and vaporizing it.
The expansion device 5 lowers the pressure of the high-pressure liquid refrigerant sent from the condenser to make a low-temperature / low-pressure liquid refrigerant.

The control unit 9 controls operations of the compressor 2, the four-way valve 3, the expansion device 5, and the like.
As described above, in the refrigeration cycle apparatus 1, the refrigerant that is the working fluid circulates while changing phase between the gas refrigerant and the liquid refrigerant, dissipates heat in the process of phase change from the gas refrigerant to the liquid refrigerant, and the gas from the liquid refrigerant It absorbs heat in the process of phase change to the refrigerant. And heating, cooling, etc. are performed using these heat dissipation and heat absorption.

  FIG. 2 is a front view of the heat exchanger according to the first embodiment. FIG. 3 is a partial perspective view of the heat exchanger according to the first embodiment. The heat exchanger 4 of the embodiment is used for one or both of the outdoor heat exchanger 4 and the indoor heat exchanger 6 of the refrigeration cycle apparatus 1. Hereinafter, the case where the heat exchanger 4 of the embodiment is used as the outdoor heat exchanger 4 of the refrigeration cycle apparatus 1 will be described as an example.

As shown in FIG. 2, the heat exchanger 4 includes a first header 10, a second header 20, a heat exchange tube 30, and fins 40.
The first header 10 is formed of a material having high thermal conductivity and low specific gravity, such as aluminum or an aluminum alloy. The first header 10 is formed in a cylindrical shape, for example, a circular cylinder whose cross section perpendicular to the Z direction is circular. Both end portions in the Z direction of the first header 10 are closed. A plurality of through holes into which the heat exchange tubes 30 are inserted are formed on the outer peripheral surface of the first header 10.
The second header 20 is formed in the same manner as the first header 10. The first header 10 and the second header 20 are arranged side by side in the X direction so as to be separated from each other.

  The heat exchange tube 30 is formed of a material having high thermal conductivity and low specific gravity, such as aluminum or an aluminum alloy. As shown in FIG. 3, the heat exchange tube 30 is formed in a flat tubular shape. That is, the heat exchange tube 30 has a predetermined width in the Y direction, is thin in the Z direction, and extends long in the X direction.

  4 is a partial cross-sectional view taken along line F4-F4 of FIG. The outer shape of the heat exchange tube 30 is formed in an oval shape. Inside the heat exchange tube 30, a plurality of refrigerant flow paths 34 are formed side by side in the Y direction. Adjacent refrigerant flow paths 34 are partitioned by flow path walls 35 parallel to the XZ plane. The plurality of refrigerant flow paths 34 penetrate the heat exchange tube 30 in the X direction.

  As shown in FIG. 2, a plurality of heat exchange tubes 30 are arranged at intervals in the Z direction. Both ends of the heat exchange tube 30 are inserted into through holes formed in the outer peripheral surfaces of the first header 10 and the second header 20. Thereby, both ends of the refrigerant flow path 34 of the heat exchange tube 30 are opened inside the first header 10 and the second header 20. The space between the first header 10 and the second header 20 and the heat exchange tube 30 is sealed and fixed by brazing or the like.

  The fin 40 is formed of a material having a high thermal conductivity and a low specific gravity, such as aluminum or an aluminum alloy. As shown in FIGS. 2 and 3, the fin 40 is a plate fin formed in a flat plate shape. The fin 40 is disposed in parallel with the YZ plane. The length of the fin 40 in the Z direction is equal to or slightly shorter than the length of the first header 10 and the second header 20 in the Z direction.

As shown in FIG. 4, the width of the fin 40 in the Y direction is larger than the width of the heat exchange tube 30 in the Y direction. A notch 43 is formed from the end of the fin 40 in the + Y direction to the −Y direction. The heat exchange tube 30 is inserted into the notch 43. The heat exchange tubes 30 and the fins 40 are fixed by brazing or the like.
As shown in FIG. 2, the plurality of fins 40 are arranged at intervals in the X direction.

Between the adjacent heat exchange tubes 30 and between the adjacent fins 40, an outside air flow path extending in the Y direction is formed. The heat exchanger 4 distributes the outside air to the outside air flow path by a blower fan (not shown) or the like. The heat exchanger 4 exchanges heat between the outside air flowing through the outside air flow path and the refrigerant flowing through the refrigerant flow path 34. Heat exchange is performed indirectly via the heat exchange tubes 30 and the fins 40. The fins 40 may be provided with irregularities. The unevenness generates turbulent flow in the outside air flowing through the outside air flow path, and improves heat exchange efficiency.
The fins 40 in the embodiment are plate fins, but may be corrugated fins. The corrugated fin is formed in a corrugated shape and is disposed between adjacent heat exchange tubes 30.

The internal structure of the heat exchanger 4 will be described.
As shown in FIG. 2, the first header 10 has a plurality of partition members 15 in the internal space 11. The partition member 15 is disposed in parallel with the XY plane, and partitions the internal space 11 of the first header 10 in the Z direction. The plurality of partition members 15 divide the internal space 11 of the first header 10 into a plurality of small chambers 11s. In the example of FIG. 2, the two partition members 15 divide the internal space 11 into three small chambers 11s. In the example of FIG. 2, the three chambers 11s have the same height in the Z direction.

  Similar to the first header 10, the second header 20 has a plurality of partition members 25. The plurality of partition members 25 divide the internal space 21 of the second header 20 into a plurality of small chambers 21s. In the example of FIG. 2, the two partition members 25 divide the internal space into three small chambers 21 s. In the example of FIG. 2, the three chambers 21s have the same height in the Z direction. The height of the small chamber 11s of the first header 10 and the height of the small chamber 21s of the second header 20 are equal.

A first end of the heat exchange tube 30 in the −X direction opens into the internal space 11 of the first header 10. A plurality of heat exchange tubes 30 are opened in the plurality of small chambers 11 s formed in the internal space 11. In the example of FIG. 5, the same number of heat exchange tubes 30 are opened for each of the plurality of small chambers 11 s.
A second end of the heat exchange tube 30 in the + X direction opens into the internal space 21 of the second header 20. A plurality of heat exchange tubes 30 are respectively opened in the plurality of small chambers 21 s formed in the internal space 21. The number of heat exchange tubes 30 opening in the small chamber 11s of the first header 10 and the number of heat exchange tubes 30 opening in the small chamber 21s of the second header 20 are the same.

The first header 10 has a first refrigerant port 17. Each of the plurality of small chambers 11 s has a first refrigerant port 17. The first refrigerant port 17 is formed below each small chamber 11s.
The second header 20 has a second refrigerant port 18. Each of the plurality of small chambers 21 s has a second refrigerant port 18. The second refrigerant port 18 is formed above each small chamber 21s.

  When the refrigeration cycle apparatus 1 shown in FIG. 1 performs a heating operation, the outdoor heat exchanger 4 functions as an evaporator. In this case, the refrigerant flows in the order of the first refrigerant port 17, the small chamber 11s, the heat exchange tube 30, the small chamber 21s, and the second refrigerant port 18 shown in FIG. The small chambers 11 s and 21 s partition the refrigerant flow path. The divided refrigerant distribution paths are called modules. In the heat exchanger 4, a plurality of modules are arranged in parallel. In the example of FIG. 2, three modules A, B, and C are formed by the three small chambers 11s and 21s. Module A has a small chamber 11a, module B has a small chamber 11b, and module C has a small chamber 11c.

FIG. 5 is a schematic configuration diagram of a gas extraction pipe 50 which is an example of a gas extraction unit.
The gas extraction pipe 50 is attached to the first header 10. The gas extraction pipe 50 is formed of a material having high thermal conductivity and low specific gravity, such as aluminum or aluminum alloy. The gas extraction pipe 50 includes a pipe main body 51, an extension part 59, and an internal opening 55.

  The pipe main body 51 is formed in a tubular shape, for example, a circular tube having a circular cross section perpendicular to the Z direction. The pipe body 51 is disposed at the center of the first header 10 in a cross section perpendicular to the Z direction. That is, the central axis of the pipe body 51 coincides with the central axis of the first header 10. The pipe body 51 extends in the Z direction. The lower end portion of the pipe body 51 extends to the lower end portion of the first header 10 and is closed. The upper end portion of the pipe body 51 constitutes an extending portion 59 that extends to the outside of the first header 10 through a through hole formed in the upper end portion of the first header 10. The space between the pipe body 51 and the upper end portion of the first header 10 is fixed by being sealed by brazing or the like.

  The extending portion 59 is formed at the upper end portion of the pipe main body 51. The extension part 59 connects the gas extraction pipe 50 and another pipe. The other pipe is, for example, a bypass pipe 60 described later.

  The internal opening 55 opens into the internal space 11 of the first header 10. The internal opening 55 is a through hole formed in the pipe wall of the pipe main body 51. The internal opening 55 is formed in each small chamber 11s. In the example of FIG. 5, an internal opening 55a is formed in the small chamber 11a, an internal opening 55b is formed in the small chamber 11b, and an internal opening 55c is formed in the small chamber 11c. The internal opening 55 is formed above the small chamber 11s. That is, the internal opening 55 is formed in the upper half of the small chamber 11s. Of the plurality of heat exchange tubes 30 opening to the small chamber 11s, the internal opening 55 is disposed above the heat exchange tube 30 disposed at the uppermost position. That is, the lower end portion of the internal opening 55 is disposed above the upper end portion of the heat exchange tube 30 disposed at the uppermost position.

  Let D be the distance from the end of the extension 59 to the internal opening 55 along the piping path of the gas extraction pipe 50. The opening area of the internal opening 55 having a large distance D is larger than the opening area of the internal opening 55 having a small distance D. In the example of FIG. 5, the distance Da to the internal opening 55a, the distance Db to the internal opening 55b, and the distance Dc to the internal opening 55c have a relationship of Da <Db <Dc. At this time, the opening area Fa of the internal opening 55a, the opening area Fb of the internal opening 55b, and the opening area Fc of the internal opening 55c have a relationship of Fa <Fb <Fc.

As shown in FIG. 1, the refrigeration cycle apparatus 1 includes a bypass pipe 60, a fluid control valve 62, a heating unit 70, and a pair of temperature sensors 71 and 72.
A first end of the bypass pipe 60 is connected to an extension part 59 of the gas extraction pipe disposed outside the first header of the outdoor heat exchanger 4. A second end of the bypass pipe 60 is connected to a suction side pipe (suction line) of the compressor 2 and communicates with a refrigerant inlet of the compressor 2. As a result, the bypass pipe 60 bypasses the outdoor heat exchanger 4 by connecting the gas extraction pipe to the refrigerant inlet of the compressor 2.

The fluid control valve 62 is an example of a flow rate adjustment mechanism, and performs flow rate adjustment of the refrigerant flowing through the bypass pipe 60. The fluid control valve 62 can adjust and close the valve opening. The fluid control valve 62 is provided at an arbitrary position of the bypass pipe 60.
The heating unit 70 heats the refrigerant flowing through the bypass pipe 60. The heating source of the heating unit 70 is arbitrary. In the example of FIG. 1, the piping 7 h on the upstream side of the expansion device 5 is used as a heating source for the heating unit 70 when the refrigeration cycle apparatus 1 performs a heating operation. The heating unit 70 heats the refrigerant by exchanging heat between the refrigerant flowing through the bypass pipe 60 and the heating source.

  The pair of temperature sensors 71 and 72 are provided on both sides of the heating unit 70 along the bypass pipe 60. The pair of temperature sensors 71 and 72 includes a first temperature sensor 71 and a second temperature sensor 72. The first temperature sensor 71 is provided on the outdoor heat exchanger 4 side of the heating unit 70. The second temperature sensor 72 is provided on the compressor 2 side of the heating unit 70. The pair of temperature sensors 71 and 72 outputs a signal corresponding to the temperature of the refrigerant flowing through the bypass pipe 60 to the control unit 9.

  The control unit 9 controls the operation of the fluid control valve 62. When the heat exchanger 4 functions as a condenser, the control unit 9 closes the fluid control valve 62 so that the refrigerant does not flow through the bypass pipe 60. On the other hand, when the heat exchanger 4 functions as an evaporator, the controller 9 opens the fluid control valve 62 and causes the refrigerant to flow through the bypass pipe 60. At this time, the control unit 9 detects a refrigerant temperature difference ΔT on both sides of the heating unit 70 based on output signals from the pair of temperature sensors 71 and 72. The controller 9 controls the operation of the fluid control valve 62 based on the detected temperature difference ΔT.

A specific operation of the control unit 9 will be described.
When the refrigeration cycle apparatus 1 shown in FIG. 1 performs a heating operation, the outdoor heat exchanger 4 functions as an evaporator. At this time, a gas-liquid two-phase refrigerant with a large liquid phase component, which is evenly distributed by a refrigerant distribution mechanism (not shown), flows into the first refrigerant port 17 of the heat exchanger 4 shown in FIG. The refrigerant absorbs heat from outside air in the process of flowing through the heat exchange tube 30. Specifically, the refrigerant absorbs heat from the outside air due to the phase change from the liquid phase refrigerant to the gas phase refrigerant and the temperature rise of the gas phase refrigerant.

Of the gas-liquid two-phase refrigerant flowing into the heat exchanger 4, the liquid-phase refrigerant absorbs heat due to the phase change to the gas-phase refrigerant and the temperature rise, and thus has a large endothermic capacity. On the other hand, since the gas-phase refrigerant absorbs heat only by increasing the temperature, it has a small endothermic capacity. Therefore, if the gas-liquid two-phase refrigerant flowing through the heat exchange tube 30 contains a large amount of gas-phase refrigerant, the heat exchange efficiency of the heat exchanger 4 is lowered.
Among the gas-liquid two-phase refrigerants, the specific gravity of the liquid-phase refrigerant is large and the specific gravity of the gas-phase refrigerant is small. Therefore, only the gas phase component may flow (out of gas) through the upper heat exchange tube, and the liquid phase component may remain (liquid pool) in the lower heat exchange tube.

The heat exchanger 4 of the embodiment has a gas extraction pipe 50. The internal opening 55 of the gas extraction pipe 50 is disposed above the small chamber 11 s of the first header 10. The first refrigerant port 17 is formed below the small chamber 11s. Therefore, when the gas-liquid two-phase refrigerant flows from the first refrigerant port 17 to the lower side of the small chamber 11s, the gas phase refrigerant having a small specific gravity moves to the upper side of the small chamber 11s. The gas-phase refrigerant flows into the gas extraction pipe 50 from the internal opening 55 disposed above the small chamber 11s. The gas-phase refrigerant flows through the gas extraction pipe 50 and is extracted outside. As a result, most of the gas-phase refrigerant flowing into the small chamber 11s is taken out. Therefore, when the gas-liquid two-phase refrigerant flows into the heat exchange tube 30 from the small chamber 11s, the gas-phase refrigerant contained in the gas-liquid two-phase refrigerant decreases. As a result, the amount of heat absorbed by the refrigerant increases. Therefore, the heat exchanger 4 can improve the heat exchange efficiency.
Further, most of the gas-phase refrigerant out of the gas-liquid two-phase refrigerant flows into the gas extraction pipe 50 from the internal opening 55. Therefore, the liquid-phase refrigerant is dispersed and flows into the plurality of heat exchange tubes 30 and flows through the plurality of heat exchange tubes 30 evenly. Therefore, the heat exchanger 4 can suppress outgassing and liquid accumulation.

The gas-phase refrigerant taken out from the gas take-out pipe 50 flows into the bypass pipe 60 through the extending portion 59 shown in FIG. The gas phase refrigerant bypasses the heat exchanger 4 by the bypass pipe 60 and flows into the compressor 2.
If the liquid refrigerant flows into the internal opening 55 of the gas extraction pipe 50, the liquid refrigerant flows into the compressor 2 through the bypass pipe 60. The control unit 9 performs the following gas extraction method to suppress the liquid phase refrigerant from flowing into the compressor 2.

FIG. 6 is a flowchart of the gas extraction method.
The controller 9 performs the heating operation (S2). At this time, the gas-liquid two-phase refrigerant flows into the small chamber 11 s of the first header 10 of the heat exchanger 4. The controller 9 opens the fluid control valve 62 by a predetermined opening (S4). Thereby, a part of the gas-liquid two-phase refrigerant that has flowed into the small chamber 11 s flows into the internal opening 55 of the gas extraction pipe 50. The refrigerant flowing into the internal opening 55 flows from the gas extraction pipe 50 into the bypass pipe 60. The refrigerant flowing through the bypass pipe 60 is heated in the heating unit 70.

  The controller 9 detects the refrigerant temperature difference ΔT before and after the heating unit 70 based on the output signals of the pair of temperature sensors 71 and 72 (S5). When a gas-phase refrigerant flows through the bypass pipe 60, the temperature of the gas-phase refrigerant rises due to heat absorption from the heating unit 70. In this case, the temperature difference ΔT becomes a value larger than zero. On the other hand, when the liquid refrigerant flows through the bypass pipe 60, the temperature change of the refrigerant is small because the liquid phase refrigerant changes into a gas-phase refrigerant due to heat absorption from the heating unit 70. In this case, the temperature difference ΔT is almost zero. That is, the phase state of the refrigerant flowing through the bypass pipe 60 can be estimated based on the temperature difference ΔT.

  The controller 9 determines whether the temperature difference ΔT is larger than the predetermined value α (S6). The predetermined value α is set to a small value close to 0 in advance. If the determination in S6 is NO, it is estimated that the liquid refrigerant flows through the bypass pipe 60. In this case, the control unit 9 decreases the opening degree of the fluid control valve 62 (S8). The control unit 9 may close the fluid control valve 62. Thereby, the inflow to the compressor 2 of a liquid phase refrigerant | coolant is suppressed.

If the determination in S6 is YES, it is presumed that the gas refrigerant flows through the bypass pipe 60. In this case, the control unit 9 maintains the opening degree of the fluid control valve 62 at a predetermined opening degree. As a result, the gas-phase refrigerant flows into the compressor 2 from the bypass pipe 60.
When the determination in S6 is YES, the control unit 9 may adjust the valve opening degree of the fluid control valve 62 based on the temperature difference ΔT detected in S6. For example, the control unit 9 may increase the valve opening degree of the fluid control valve 62 when the temperature difference ΔT exceeds a predetermined value β (> α).

When the outdoor heat exchanger 4 functions as an evaporator, the refrigerant pressure on the compressor 2 side (outlet side) of the outdoor heat exchanger 4 is smaller than the refrigerant pressure on the expansion device 5 side (inlet side). By adjusting the valve opening degree of the fluid control valve 62, the refrigerant pressure on the compressor 2 side (outlet side) of the bypass pipe 60 becomes smaller than the refrigerant pressure on the expansion device 5 side (inlet side). As a result, the refrigerant is supplied to the compressor 2 from both the outdoor heat exchanger 4 and the bypass pipe 60.
Thus, the process of the gas extraction method is completed.

  When the refrigeration cycle apparatus 1 performs a cooling operation, the outdoor heat exchanger 4 functions as a condenser. In this case, the refrigerant flows in the order of the second refrigerant port 18, the small chamber 21s, the heat exchange tube 30, the small chamber 11s, and the first refrigerant port 17 shown in FIG. That is, the refrigerant that has finished heat exchange with the heat exchange tube 30 flows into the small chamber 11s. Therefore, it is not necessary to take out the gas phase component of the gas-liquid two-phase refrigerant flowing into the small chamber 11s. Therefore, the control unit 9 closes the fluid control valve 62 shown in FIG. Thereby, the liquid-phase refrigerant which flowed into the small chamber 11s does not flow into the internal opening 55 of the gas extraction pipe 50 shown in FIG. Therefore, inflow of the liquid phase refrigerant into the compressor 2 is prevented.

  As described in detail above, the heat exchanger 4 of the embodiment shown in FIG. 2 has the first header 10 and the second header 20, and the plurality of heat exchange tubes 30. The first header 10 and the second header 20 are formed in a cylindrical shape, and are arranged side by side in the X direction so as to be separated from each other. The plurality of heat exchange tubes 30 are arranged at intervals in the central axis direction (Z direction) of the first header 10 and the second header 20, and both end portions open to the inside of the first header 10 and the second header 20. . The first header 10 has a gas extraction pipe 50 shown in FIG. The gas extraction pipe 50 has an internal opening 55 and an extension part 59. The internal opening 55 opens to the small chamber 11 s of the first header 10. The extension part 59 is provided outside the first header 10. The internal opening 55 is disposed above the small chamber 11 s of the first header 10.

  When the gas-liquid two-phase refrigerant flows into the small chamber 11s, the gas phase refrigerant having a small specific gravity moves above the small chamber 11s. Since the internal opening 55 is disposed above the small chamber 11 s, the gas-phase refrigerant flows into the gas extraction pipe 50 from the internal opening 55 and is taken out of the first header 10. Thereby, when the gas-liquid two-phase refrigerant flows into the heat exchange tube 30 from the small chamber 11s, the gas-phase refrigerant contained in the gas-liquid two-phase refrigerant decreases. Thereby, since the heat absorption amount of the refrigerant increases, the heat exchanger 4 can improve the heat exchange efficiency.

  The first header 10 is divided into a plurality of small chambers 11s in the Z direction. The internal opening 55 opens to each of the plurality of small chambers 11s. The opening area of the internal opening 55 having a large distance D from the extending portion 59 along the piping path of the gas extraction pipe 50 is larger than the opening area of the internal opening 55 having a small distance D.

  The greater the distance D, the greater the pressure loss that occurs in the gas phase refrigerant in the course of flowing through the gas extraction pipe 50. Therefore, it is difficult for the gas-phase refrigerant to flow into the internal opening 55 having a large distance D. By increasing the opening area of the internal opening 55 having a large distance D, the gas phase refrigerant can easily flow into the internal opening 55. Thereby, the imbalance of the inflow amount of the gas-phase refrigerant is suppressed for the internal opening 55 that opens to each of the plurality of small chambers 11s. As a result, the liquid level of the liquid phase refrigerant in the plurality of small chambers 11s becomes uniform.

The internal opening 55 is disposed above the heat exchange tube 30 disposed at the top of the plurality of heat exchange tubes 30 opening to the small chamber 11s.
Thereby, it is possible to suppress the liquid phase refrigerant from flowing into the internal opening 55. Therefore, it is possible to suppress the liquid phase refrigerant from flowing into the compressor 2 via the gas extraction pipe 50 and the bypass pipe 60.

  The refrigeration cycle apparatus 1 according to the embodiment shown in FIG. 1 includes a heat exchanger 4, a compressor 2, a bypass pipe 60, a fluid control valve 62, and a control unit 9. The compressor 2 compresses the refrigerant. The bypass pipe 60 connects the gas extraction pipe 50 to the refrigerant inlet of the compressor 2. The fluid control valve 62 is provided in the bypass pipe 60 and adjusts the flow rate of the refrigerant flowing through the bypass pipe 60. The control unit 9 controls the operation of the fluid control valve 62.

  When the heat exchanger 4 functions as an evaporator, the control unit 9 opens the fluid control valve 62 and causes the refrigerant to flow through the bypass pipe 60. Thereby, the gas phase refrigerant taken out of the first header 10 bypasses the heat exchanger 4 and flows into the compressor 2. Therefore, the refrigerant can be circulated. On the other hand, when the heat exchanger 4 functions as a condenser, the control unit 9 closes the fluid control valve 62 so that the refrigerant does not flow through the bypass pipe 60. Thereby, since a refrigerant | coolant is not taken out outside the 1st header 10, it can prevent that a liquid phase refrigerant | coolant flows into the compressor 2. FIG.

  The heating unit 70 heats the refrigerant flowing through the bypass pipe 60. The pair of temperature sensors 71 and 72 are provided on both sides of the heating unit 70 along the bypass pipe 60, and output a signal corresponding to the temperature of the refrigerant flowing through the bypass pipe 60. The control unit 9 detects a refrigerant temperature difference ΔT on both sides of the heating unit 70 based on signals output from the pair of temperature sensors 71 and 72. The controller 9 controls the operation of the fluid control valve 62 based on the detected temperature difference ΔT.

  When a gas-phase refrigerant flows through the bypass pipe 60, the temperature of the refrigerant rises due to heat absorption from the heating unit 70. When a liquid phase refrigerant flows through the bypass pipe 60, the temperature change of the refrigerant due to heat absorption from the heating unit 70 is small. The controller 9 controls the operation of the fluid control valve 62 based on the detected temperature difference ΔT. Thereby, it can control that a liquid phase refrigerant flows into compressor 2.

A modification of the refrigeration cycle apparatus will be described.
FIG. 7 is a schematic configuration diagram of a refrigeration cycle apparatus according to a modification of the first embodiment. The refrigeration cycle apparatus 101 of the modification shown in FIG. 7 is different from the refrigeration cycle apparatus 1 of the first embodiment shown in FIG. 1 in that it has a capillary tube 64 and an on-off valve 66. Among the configurations of the modified example, configurations other than those described below are the same as those in the first embodiment.

  The refrigeration cycle apparatus 101 includes a capillary tube 64 and an on-off valve 66 as a flow rate adjusting mechanism. In the present application, “flow rate adjustment” means changing the flow rate temporally or spatially. That is, the flow rate adjustment includes changing the flow rate with time by the on-off valve 66 (before and after the operation time of the on-off valve 66). The flow rate adjustment includes spatially changing the flow rate by the capillary tube 64 (between the upstream side and the downstream side of the capillary tube 64).

The capillary tube 64 and the on-off valve 66 are provided in the bypass pipe 60.
The capillary tube 64 makes the refrigerant pressure on the compressor 2 side (outlet side) of the bypass pipe 60 smaller than the refrigerant pressure on the expansion device 5 side (inlet side). As a result, the refrigerant is supplied to the compressor 2 from both the outdoor heat exchanger 4 and the bypass pipe 60.
The on-off valve 66 switches between opening and closing.

  When the refrigeration cycle apparatus 101 performs the heating operation, the control unit 9 opens the on-off valve 66. Thereby, a gaseous-phase refrigerant | coolant flows in into the internal opening 55 of the gas extraction piping 50 shown by FIG. The gas phase refrigerant flows into the compressor 2 through the gas extraction pipe 50 and the bypass pipe 60.

When the refrigeration cycle apparatus 101 performs the cooling operation, the control unit 9 closes the on-off valve 66. Thereby, a refrigerant | coolant does not flow into the internal opening 55 of the gas extraction piping 50 shown by FIG. Therefore, the liquid phase refrigerant can be prevented from flowing into the compressor 2.
The refrigeration cycle apparatus 101 of the modified example shown in FIG. 7 has the same effects as the refrigeration cycle apparatus 1 of the first embodiment shown in FIG.

(Second Embodiment)
FIG. 8 is a front view of the heat exchanger 204 of the second embodiment. Among the configurations of the second embodiment, configurations other than the configurations described below are the same as those of the first embodiment.
The heat exchanger 204 includes a first heat exchanger 204g, a second heat exchanger 204h, and a connection channel 26. The first heat exchanger 204g is disposed below, and the second heat exchanger 204h is disposed above. Of the configuration of the first heat exchanger 204g, configurations other than those described below are the same as those of the heat exchanger 4 of the first embodiment shown in FIG.

  The second header 220 of the second heat exchanger 204 h has a plurality of partition members 25 in the internal space 22. The plurality of partition members 25 divide the internal space 22 of the second header 220 into a plurality of small chambers 22s. In the example of FIG. 8, the two partition members 25 divide the internal space 22 into three small chambers 22 s. Module A has a small chamber 22a, module B has a small chamber 22b, and module C has a small chamber 22c.

  The connection flow path 26 connects the small chamber 21s of the second header 20 of the first heat exchanger 204g and the small chamber 22s of the second header 220 of the second heat exchanger 204h. Connection channels 26 are respectively formed between the plurality of small chambers 21s formed in the first heat exchanger 204g and the plurality of small chambers 22s formed in the second heat exchanger 204h. In the example of FIG. 5, the connection channel 26 connects the nth chamber 21s (n is a natural number) from above the first heat exchanger 204g and the nth chamber 22s from below the second heat exchanger 204h. To do. Thereby, the intersection of the plurality of connection flow paths 26 is avoided, and the layout is simplified. The connection channel 26 may connect the small chamber 21s and the small chamber 22s in a combination other than the above.

The first header 210 of the second heat exchanger 204h does not have a partition member in the internal space 12.
The 2nd refrigerant | coolant port 18 is formed above the 1st header 210 of the 2nd heat exchanger 204h (upper half part).

  A refrigerant flow path of the heat exchanger 204 when the refrigeration cycle apparatus 1 shown in FIG. 1 performs the heating operation will be described. The refrigerant flows into the first refrigerant port 17 of the first heat exchanger 204g and flows through the first heat exchanger 204g. The refrigerant flows from the first heat exchanger 204g into the second heat exchanger 204h through the connection flow path 26. The refrigerant flows through the second heat exchanger 204h and flows out from the second refrigerant port 18. The refrigerant absorbs heat from the outside air in the process of flowing through the heat exchange tubes 30 of the first heat exchanger 204g and the second heat exchanger 204h.

The gas extraction pipe 250 will be described.
As shown in FIG. 8, the gas extraction pipe 250 includes a first pipe body 51, a first extension part 59a, a second pipe body 52, a second extension part 59b, a first internal opening 55a, 55b, 55c and second internal openings 56a, 56b, 56c.

The first piping main body 51 extends upward from the first header 10 of the first heat exchanger 204g. The first piping main body 51 extends through the first header 210 of the second heat exchanger 204h and extends above the first header 210.
The first extension 59 a is formed at the upper end of the first pipe body 51.

The second piping main body 52 extends upward from the second header 20 of the first heat exchanger 204g. The second piping main body 52 extends through the second header 220 of the second heat exchanger 204 h and extends above the second header 220. The lower end portion of the second pipe main body 52 extends to the lower end portion of the second header 20 and is closed. The lower end portion of the second pipe main body 52 may be blocked by the lower end portion of the second header 220 of the second heat exchanger 204h.
The second extending portion 59 b is formed at the upper end portion of the second pipe main body 52.

  The first internal openings 55a, 55b, and 55c are formed so as to open to the small chambers 11a, 11b, and 11c in the internal space of the first header 10 of the first heat exchanger 204g, respectively. On the other hand, there is no first internal opening that opens into the internal space 12 of the first header 210 of the second heat exchanger 204h.

  The second internal openings 56a, 56b, 56c are formed so as to open to the small chambers 22a, 22b, 22c in the internal space of the second header 220 of the second heat exchanger 204h, respectively. On the other hand, there is no second internal opening that opens into the internal space 21 of the second header 20 of the first heat exchanger 204g. The second inner opening may be opened in one or both of the second header 220 and the second header 20.

  When the refrigeration cycle apparatus 1 shown in FIG. 1 performs the heating operation, the gas-liquid two-phase refrigerant flows into the small chamber 11s from the first refrigerant port 17 of the first heat exchanger 204g. At this time, the gas-phase refrigerant flows into the first pipe main body 51 from the first internal openings 55a, 55b, and 55c disposed above the small chambers 11a, 11b, and 11c. The gas-phase refrigerant flows through the first pipe body 51 and is taken out from the first extending portion 59a. The remaining refrigerant flows through the heat exchange tube 30 and the small chamber 21 s and flows into the connection channel 26.

  The gas-liquid two-phase refrigerant flows into the small chamber 22s of the second heat exchanger 204h from the connection flow path 26. If the gas-liquid two-phase refrigerant flowing into the heat exchange tube 30 from the small chamber 22s contains a large amount of gas phase components, the heat exchange efficiency of the second heat exchanger 204h is lowered. The gas-phase refrigerant that has flowed into the small chamber 22s flows into the second pipe main body 52 from the second internal openings 56a, 56b, and 56c disposed above the small chambers 22a, 22b, and 22c. The gas-phase refrigerant flows through the second piping main body 52 and is taken out from the second extending portion 59b.

Similarly to the heat exchanger 4 of the first embodiment, the heat exchanger 204 of the second embodiment can also improve the heat exchange efficiency.
The heat exchanger 204 of the second embodiment is formed by combining a separate first heat exchanger 204g and second heat exchanger 204h. On the other hand, the first heat exchanger 204g and the second heat exchanger 204h may be integrally formed.
The heat exchanger 204 of the second embodiment is formed by connecting two first heat exchangers 204g and a second heat exchanger 204h with one connection channel 26. On the other hand, n (n is a natural number) heat exchangers may be formed by connecting n-1 connection flow paths.

The internal space of the header of the embodiment is divided into a plurality of small chambers. In this case, the gas extraction pipe has an internal opening in each small chamber. On the other hand, the internal space of the header may not be divided into a plurality of small chambers. In this case, the gas extraction pipe has an internal opening in one internal space of the header.
The gas extraction pipe of the embodiment extends above the header through the upper end of the header. On the other hand, the gas extraction pipe may extend below the header through the lower end of the header. The gas extraction pipe may extend through the header side wall through the side wall of the header.

The gas extraction pipe of the embodiment is disposed coaxially with the header inside the header. On the other hand, the gas extraction pipe may be arranged offset from the central axis of the header inside the header. The gas extraction pipe may be disposed on the outer peripheral surface of the header.
The gas extraction pipe of the embodiment has one internal opening in the small chamber. On the other hand, the gas extraction pipe may have a plurality of internal openings in the small chamber.

According to at least one embodiment described above, the internal opening 55 of the gas extraction pipe 50 is disposed above the small chamber 11 s of the first header 10. Thereby, the heat exchanger can increase the heat absorption amount of the refrigerant and improve the heat exchange efficiency.
In the above-described embodiment, the gas extraction pipe having the internal opening that opens above the internal space of one header and the extending portion that extends to the outside of one header has been described as the gas extraction means. However, the gas extraction means of the present invention is not limited to this. For example, an opening may be formed in the side wall of the header at a position above the internal space of the header, and a bypass pipe may be connected to the opening.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  Da, Db, Dc ... distance, 1,101 ... refrigeration cycle apparatus, 2 ... compressor, 4,204 ... heat exchanger, 9 ... control unit, 10,210 ... first header, 11 ... internal space, 11s ... small chamber (Internal space), 20, 220 ... second header, 22 ... internal space, 22s ... small chamber (internal space), 30 ... heat exchange tube, 50 ... gas extraction pipe, 55, 55a, 55b, 55c ... internal opening, first 1 internal opening, 56a, 56b, 56c ... 2nd internal opening, 59 ... extension part, 60 ... bypass piping, 62 ... fluid control valve (flow rate adjusting mechanism), 64 ... capillary tube (flow rate adjusting mechanism), 66 ... opening and closing Valve (flow rate adjusting mechanism), 70 ... heating unit, 71 ... first temperature sensor, 72 ... second temperature sensor.

Claims (6)

A first header and a second header formed in a cylindrical shape and arranged side by side apart from each other;
A plurality of heat exchange tubes that are arranged at intervals in the central axis direction of the first header and the second header, and whose both end portions are opened inside the first header and the second header;
Gas extraction means provided on at least one of the first header and the second header, and for extracting the gas refrigerant in the internal space of the header to the outside of the header,
Heat exchanger. The gas extraction means is a gas extraction pipe,
The gas extraction pipe has an internal opening that is an opening that opens into the internal space of the header, and an extending portion that extends to the outside of the header.
The internal opening is disposed above the internal space of the header.
The heat exchanger according to claim 1. The header is divided into a plurality of internal spaces in the central axis direction,
The internal opening opens to each of the plurality of internal spaces,
The opening area of the internal opening having a large distance from the extending portion along the piping path of the gas extraction piping is the opening area of the internal opening having a small distance from the extending portion along the piping path of the gas extraction piping. Larger than the opening area,
The heat exchanger according to claim 2. The internal opening is disposed above the heat exchange tube disposed at the uppermost of the plurality of heat exchange tubes that open to the internal space.
The heat exchanger according to claim 2 or 3. The heat exchanger according to any one of claims 1 to 4,
A compressor for compressing the refrigerant;
A bypass pipe for communicating the gas extraction means with a refrigerant inlet of the compressor;
A flow rate adjusting mechanism that is provided in the bypass piping and adjusts the flow rate of the refrigerant flowing through the bypass piping;
A control unit for controlling the operation of the flow rate adjusting mechanism,
Refrigeration cycle equipment. A heating unit for heating the refrigerant flowing through the bypass pipe;
A pair of temperature sensors provided on both sides of the heating unit along the bypass pipe and outputting a signal corresponding to the temperature of the refrigerant flowing through the bypass pipe;
The controller is
Based on the signals output from the pair of temperature sensors, detect the temperature difference of the refrigerant on both sides of the heating unit,
Controlling the operation of the flow rate adjusting mechanism based on the detected temperature difference;
The refrigeration cycle apparatus according to claim 5.

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