JPWO2019176089A1 - Heat exchanger and refrigeration cycle equipment - Google Patents

Abstract

The heat exchanger of the embodiment has a first header and a second header, and a plurality of heat exchange tubes. The plurality of heat exchange tubes have a first heat exchange tube and a second heat exchange tube. A gas-liquid two-phase refrigerant having a large amount of liquid phase components flows through the first heat exchange tube. The second heat exchange tube communicates with the first heat exchange tube, and a gas-liquid two-phase refrigerant having a large amount of gas phase components flows through the second heat exchange tube. The second heat exchange tube has an upper second heat exchange tube and a lower second heat exchange tube. The upper second heat exchange tube is arranged above the first heat exchange tube. The lower second heat exchange tube is arranged below the first heat exchange tube.

Description

Embodiments of the present invention relate to heat exchangers and refrigeration cycle devices.

A heat exchanger that exchanges heat between the refrigerant and the outside air is used. When a heat exchanger is used as an evaporator of a refrigeration cycle device, frost adheres (frosts) to the heat exchanger. When frost is formed on the heat exchanger, the refrigeration cycle device suspends normal operation and performs defrosting operation. A heat exchanger that can complete defrosting in a short time defrosting operation is required.

Japanese Unexamined Patent Publication No. 2012-163319

An object to be solved by the present invention is to provide a heat exchanger and a refrigeration cycle device capable of completing defrosting in a short defrosting operation.

The heat exchanger of the embodiment has 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 tubular 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 inside the first header and the second header. The plurality of heat exchange tubes include a first heat exchange tube and a second heat exchange tube. A gas-liquid two-phase refrigerant having a large amount of liquid phase components flows through the first heat exchange tube. The second heat exchange tube communicates with the first heat exchange tube, and a gas-liquid two-phase refrigerant having a large amount of gas phase components flows through the second heat exchange tube. The second heat exchange tube has an upper second heat exchange tube and a lower second heat exchange tube. The upper second heat exchange tube is arranged above the first heat exchange tube. The lower second heat exchange tube is arranged below the first heat exchange tube.

Schematic diagram of the refrigeration cycle device. The front view of the heat exchanger of the first embodiment. Partial perspective view of the heat exchanger of the first embodiment. FIG. 2 is a partial cross-sectional view taken along the line F4-F4 of FIG. The schematic block diagram of the heat exchanger of the 1st Embodiment. The schematic block diagram of the heat exchanger of the modification of 1st Embodiment. Flowchart of defrosting method. The schematic block diagram of the heat exchanger of the 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 the vertical direction, and the + Z direction is the upward direction. The X direction is the central axis direction (extending direction) of the heat exchange tube. For example, the X direction is the horizontal direction, and the + X direction is the direction from the first header to the second header. The Y direction is a direction perpendicular to the X and Z directions.

FIG. 1 is a schematic configuration diagram of a refrigeration cycle device.
As shown in FIG. 1, the refrigeration cycle device 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 device 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 broken arrow, and the flow direction of the refrigerant during the defrosting (cooling) operation is indicated by a solid arrow.

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

The four-way valve 3 reverses the flow direction of the refrigerant and switches between the heating operation and the defrosting 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 device 1 causes the indoor heat exchanger 6 to function as a condenser and the outdoor heat exchanger 4 to function as an evaporator to heat the room. During the defrosting 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 device 1 causes the outdoor heat exchanger 4 to function as a condenser, the indoor heat exchanger 6 to function as an evaporator, and defrosts the outdoor heat exchanger 4.

The condenser makes a high-pressure liquid refrigerant by radiating high-temperature and high-pressure gaseous refrigerant discharged from the compressor 2 to the outside air and condensing it. The evaporator converts a low-temperature, low-pressure liquid refrigerant sent from the expansion device 5 into a low-pressure gas refrigerant by absorbing heat from the outside air and vaporizing it. A blower fan 4a is provided in the vicinity of the outdoor heat exchanger 4. The blower fan 4a blows outside air to the outdoor heat exchanger 4.
The expansion device 5 lowers the pressure of the high-pressure liquid refrigerant sent from the condenser to obtain a low-temperature / low-pressure liquid refrigerant.

The control unit 9 controls the operation of the compressor 2, the four-way valve 3, the expansion device 5, and the like.
In this way, in the refrigeration cycle device 1, the refrigerant as the working fluid circulates between the gas refrigerant and the liquid refrigerant while changing the phase, dissipates heat in the process of changing the phase from the gas refrigerant to the liquid refrigerant, and the liquid refrigerant to the gas. It absorbs heat in the process of changing phase to the refrigerant. Then, heating and defrosting are performed by utilizing these heat dissipation and heat absorption.

(First Embodiment)
FIG. 2 is a front view of the heat exchanger of the first embodiment. FIG. 3 is a partial perspective view of the heat exchanger of the first embodiment. The heat exchanger 4 of the embodiment is used as the outdoor heat exchanger 4 of the refrigeration cycle device 1. The heat exchanger 4 of the embodiment may be used as the indoor heat exchanger 6 of the refrigeration cycle device 1. Hereinafter, the case where the heat exchanger 4 of the embodiment is used as the outdoor heat exchanger 4 of the refrigeration cycle device 1 will be described as an example.

As shown in FIG. 2, the heat exchanger 4 has 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 a high thermal conductivity and a low specific gravity, such as aluminum or an aluminum alloy. The first header 10 is formed in a tubular shape, for example, in a cylindrical shape having a circular cross section. Both ends of the first header 10 in the Z direction are closed. A plurality of through holes into which the heat exchange tube 30 is 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 so as to be separated from each other in the X direction.

The heat exchange tube 30 is made of a material having a high thermal conductivity and a 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.

FIG. 4 is a partial cross-sectional view taken along the 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. The adjacent refrigerant flow paths 34 are partitioned by a flow path wall 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. As a result, 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 first header 10 and the second header 20 and the heat exchange tube 30 are 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. The fin 40 is a plate fin formed in a flat plate shape as shown in FIGS. 2 and 3. The fins 40 are arranged parallel to 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 + Y direction end edge of the fin 40 to the −Y direction. A heat exchange tube 30 is inserted into the notch 43. The heat exchange tube 30 and the fin 40 are fixed by brazing or the like.
As shown in FIG. 2, a plurality of fins 40 are arranged at intervals in the X direction.

An outside air flow path extending in the Y direction is formed between the adjacent heat exchange tubes 30 and between the adjacent fins 40. The heat exchanger 4 circulates the outside air through the outside air flow path by the blower fan 4a (see FIG. 1). 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. The heat exchange is indirectly performed via the heat exchange tube 30 and the fins 40. The fin 40 may be provided with irregularities. The unevenness generates turbulent airflow in the outside air flowing through the outside air flow path, and improves heat exchange efficiency.
The fin 40 of the embodiment is a plate fin, but may be a corrugated fin. The corrugated fins are wavy and are arranged between adjacent heat exchange tubes 30.

The internal structure of the heat exchanger 4 will be described.
FIG. 5 is a schematic configuration diagram of the heat exchanger 4 of the first embodiment. In FIG. 5, the heat exchange tube 30 is represented by a box. One box of FIG. 5 contains a plurality of heat exchange tubes 30 arranged side by side and having similar functions.

The first header 10 has a plurality of partition members. The partition member is arranged parallel to the XY plane and partitions the inside of the first header 10 in the Z direction. The plurality of partition members divide the inside of the first header 10 into a plurality of chambers. The plurality of partition members include an upper partition member 15H, a lower partition member 15L, and an intermediate partition member 15s.

The upper partition member 15H is arranged upward (+ Z direction), and the lower partition member 15L is arranged downward (−Z direction). Inside the first header 10, the first chamber 11 is formed between the upper partition member 15H and the lower partition member 15L. A second chamber 12 is formed between the upper partition member 15H and the upper end portion of the first header 10. A lowermost second chamber 12z is formed between the lower partition member 15L and the lower end of the first header 10.

The intermediate partition member 15s is arranged in the first chamber 11 between the upper partition member 15H and the lower partition member 15L. The plurality of intermediate partition members 15s divide the first chamber 11 into a plurality of first chambers 11a and 11z. In the example of FIG. 5, four intermediate partition members 15s divide the first chamber 11 into five first chambers 11a and 11z. In the example of FIG. 5, the heights of the five first chambers 11a and 11z in the Z direction are equal.

Like the first header 10, the second header 20 has a plurality of partition members. The plurality of partition members include an upper partition member 25H, a lower partition member 25L, and an intermediate partition member 25s.
The upper partition member 25H is arranged at the same height as the upper partition member 15H of the first header 10. The lower partition member 25L is arranged above the lower partition member 15L of the first header 10. The lower partition member 25L is arranged at the same height as the intermediate partition member 15s arranged at the lowermost part of the first chamber 11 of the first header 10.

Inside the second header 20, the first chamber 21 is formed between the upper partition member 25H and the lower partition member 25L. A second chamber 22 is formed between the upper partition member 25H and the upper end portion of the second header 20. A lowermost chamber 20z is formed between the lower partition member 25L and the lower end portion of the second header 20.

The intermediate partition member 25s is arranged in the first chamber 21 between the upper partition member 25H and the lower partition member 25L. The plurality of intermediate partition members 25s divide the first chamber 21 into a plurality of first small chambers 21a. In the example of FIG. 5, three intermediate partition members 25s divide the first chamber 21 into four first chambers 21a. In the example of FIG. 5, the heights of the four first chambers 21a in the Z direction are equal. The height of the first chambers 11a and 11z of the first header 10 is equal to the height of the first chamber 21a of the second header 20.

The intermediate partition member 25s is also arranged in the second chamber 22 between the upper partition member 25H and the upper end portion of the second header 20. A plurality of intermediate partition members 25s divide the second chamber 22 into a plurality of second small chambers 22a. In the example of FIG. 5, three intermediate partition members 25s divide the second chamber 22 into four second chambers 22a. In the example of FIG. 5, the heights of the four second chambers 22a in the Z direction are equal. The height of the second chamber 22a is larger than the height of the first chamber 21a.

The heat exchange tube 30 has a first heat exchange tube 31 and a second heat exchange tube 32. The first heat exchange tube 31 is arranged downward from the center of the heat exchanger 4 in the Z direction. The second heat exchange tube 32 has an upper second heat exchange tube 32u and a lower second heat exchange tube 32z. The upper second heat exchange tube 32u is arranged above the first heat exchange tube 31. The lower second heat exchange tube 32z is arranged below the first heat exchange tube 31 and is arranged at the lowermost part of the plurality of heat exchange tubes 30.

The first end of the first heat exchange tube 31 in the −X direction opens into the first chamber 11 of the first header 10. A plurality of first heat exchange tubes 31 are opened in the plurality of first chambers 11a and 11z formed in the first chamber 11, respectively. In the example of FIG. 5, the same number of first heat exchange tubes 31 are opened for each of the plurality of first chambers 11a and 11z. The lowermost first heat exchange tube 31z opens in the lowermost first small chamber 11z arranged at the lowermost of the plurality of first small chambers 11a and 11z. The lowermost first heat exchange tube 31z is arranged at the lowermost part of the first heat exchange tube 31. Therefore, the lowermost first heat exchange tube 31z is closest to the lower second heat exchange tube 32z.

The second end of the first heat exchange tube 31 in the + X direction opens into the first chamber 21 or the lowermost chamber 20z of the second header 20. The lowermost first heat exchange tube 31z of the first heat exchange tube 31 opens into the lowermost chamber 20z. The upper first heat exchange tube 31u arranged above the lowermost first heat exchange tube 31z opens into the first chamber 21. A plurality of upper first heat exchange tubes 31u are opened in each of the plurality of first chambers 21a formed in the first chamber 21. The number of upper first heat exchange tubes 31u opening in the first chamber 11a of the first header 10 is the same as the number of upper first heat exchange tubes 31u opening in the first chamber 21a of the second header 20.

The first end of the upper second heat exchange tube 32u in the −X direction opens into the second chamber 12 of the first header 10.
The first end of the lower second heat exchange tube 32z in the −X direction opens into the lowermost second chamber 12z of the first header 10.

The second end of the upper second heat exchange tube 32u in the + X direction opens into the second chamber 22 of the second header 20. A plurality of upper second heat exchange tubes 32u are opened in each of the plurality of second chambers 22a formed in the second chamber 22. In the example of FIG. 5, the same number of upper second heat exchange tubes 32u are opened for each of the four second chambers 22a. The number of upper second heat exchange tubes 32u opening in the second chamber 22a is larger than the number of upper first heat exchange tubes 31u opening in the first chamber 21a.
The second end of the lower second heat exchange tube 32z in the + X direction opens into the lowermost chamber 20z of the second header 20. The number of lower second heat exchange tubes 32z is equal to or greater than the number of lowermost first heat exchange tubes 31z.

The first header 10 has a first refrigerant port 17, a second refrigerant port 18, and a temperature sensor 14.
The first refrigerant port 17 is composed of a first refrigerant port 17a formed in each of a plurality of first small chambers 11a constituting the first chamber 11 and a lowermost first refrigerant port 17z formed in the lowermost first small chamber 11z. It is configured. The first refrigerant port 17a and the lowermost first refrigerant port 17z constituting the first refrigerant port 17 of the heat exchanger 4 are merged by the connecting pipe 17b and connected to the same constituent member of the refrigeration cycle device 1. In the example of FIG. 1, the first refrigerant port 17 of the outdoor heat exchanger 4 is connected to the expansion device 5.

The second refrigerant port 18 is composed of a second refrigerant port 18a formed above (upper half) of the second chamber 12 and a lowermost second refrigerant port 18z formed in the lowermost second chamber 12z. There is. The second refrigerant port 18a and the lowermost second refrigerant port 18z constituting the second refrigerant port 18 of the heat exchanger 4 are merged by the connecting pipe 18b and connected to the same component of the refrigeration cycle device 1. In the example of FIG. 1, the second refrigerant port 18 of the outdoor heat exchanger 4 is connected to the four-way valve 3.

The temperature sensor 14 is connected to the lowermost first refrigerant port 17z that constitutes the first refrigerant port 17. The temperature sensor 14 outputs a signal corresponding to the temperature of the refrigerant flowing through the first refrigerant port 17 to the control unit 9 of the refrigeration cycle device 1. The control unit 9 detects the temperature of the refrigerant flowing through the first refrigerant port 17 based on the signal input from the temperature sensor 14.

The second header 20 has a connection flow path 26. The connection flow path 26 connects between the first chamber 21 and the second chamber 22. A connection flow path 26a is formed between the plurality of first chambers 21a formed in the first chamber 21 and the plurality of second chambers 22a formed in the second chamber 22, respectively. In the example of FIG. 5, the connection flow path 26a connects the first chamber 21a, which is the nth (n is a natural number) from the top of the first chamber 21, and the second chamber 22a, which is the nth from the bottom of the second chamber 22. To do. As a result, the intersection of the plurality of connection flow paths 26 is avoided, and the layout is simplified. The connection flow path 26a may connect the first chamber 21a and the second chamber 22a in a combination other than the above.

FIG. 6 is a schematic configuration diagram of the heat exchanger 104 of the modified example of the first embodiment. Among the configurations of the modified examples, the configurations other than the configurations described below are the same as the configurations of the first embodiment.
The heat exchanger 104 does not have intermediate partition members 15s and 25s in the first header 10 and the second header 20. That is, the first chamber 11 of the first header 10 is not divided into a plurality of first small chambers. The first chamber 21 of the second header 20 is also not divided into a plurality of first chambers. The second chamber 22 of the second header 20 is also not divided into a plurality of second chambers.

The first refrigerant port 17 is formed below the first chamber 11 of the first header 10. The connection flow path 26 connects the upper part of the first chamber 21 of the second header 20 and the lower part of the second chamber 22. As a result, the gas-liquid two-phase refrigerant having a large amount of liquid phase components flows in and out from below, and the gas-liquid two-phase refrigerant having many gas phase components flows in and out from above. Therefore, it is possible to suppress a refrigerant shortage due to the retention of the refrigerant.
The heat exchanger 104 of the modified example also has the same function and effect as the heat exchanger 4 of the first embodiment.

The flow path of the refrigerant in the heat exchanger 4 of the first embodiment will be described.
As described above, in FIG. 5, the flow direction of the refrigerant during the heating operation is indicated by a broken arrow, and the flow direction of the refrigerant during the defrosting operation is indicated by a solid arrow.

The flow path of the refrigerant when the refrigeration cycle device 1 performs the heating operation will be described.
When the refrigeration cycle device 1 shown in FIG. 1 performs a heating operation, the outdoor heat exchanger 4 functions as an evaporator. At this time, the liquid refrigerant flowing out of the expansion device 5 is evenly distributed by a refrigerant distribution mechanism (not shown), and constitutes the first refrigerant port 17 of the heat exchanger 4 shown in FIG. 5 via the connecting pipe 17b. It flows into the first refrigerant port 17a and the lowermost first refrigerant port 17z.

The refrigerant flows from the first refrigerant port 17a into the first small chamber 11a constituting the first chamber 11 of the first header 10, and also flows from the lowermost first refrigerant port 17z into the lowermost first small chamber 11z.

The refrigerant flows from the first chamber 11a into the upper first heat exchange tube 31u, and flows from the lowermost first chamber 11z into the lowermost first heat exchange tube 31z. In the process of flowing through the first heat exchange tube 31, the refrigerant absorbs heat from the outside air. As a result, the liquid refrigerant changes to a gas-liquid two-phase refrigerant having a large amount of liquid phase components. That is, a gas-liquid two-phase refrigerant having a large amount of liquid phase components flows through the first heat exchange tube 31.

The refrigerant flows from the upper first heat exchange tube 31u into the first small chamber 21a, and flows from the lowermost first heat exchange tube 31z into the lowermost chamber 20z.
The refrigerant flows from the first chamber 21a through the connection flow path 26a and flows into the second chamber 22a.

The refrigerant flows from the second small chamber 22a into the upper second heat exchange tube 32u, and flows from the lowermost chamber 20z into the lower second heat exchange tube 32z. In the process of flowing through the second heat exchange tube 32, the refrigerant absorbs heat from the outside air. As a result, the gas-liquid two-phase refrigerant having a large amount of liquid phase components is changed to a gas-liquid two-phase refrigerant having a large amount of gas phase components. That is, a gas-liquid two-phase refrigerant having a large amount of gas-phase components flows through the second heat exchange tube 32.

The refrigerant flows into the second chamber 12 from the upper second heat exchange tube 32u, and flows into the lowermost second chamber 12z from the lower second heat exchange tube 32z.
The refrigerant flows out of the heat exchanger 4 from the second refrigerant port 18a and the lowermost second refrigerant port 18z. The gaseous refrigerant flowing out of the outdoor heat exchanger 4 shown in FIG. 1 flows into the compressor 2 via the four-way valve 3.

As described above, the refrigerant is the first chamber 11a of the first header 10, the upper first heat exchange tube 31u, the first chamber 21a of the second header, the connection flow path 26a, the second chamber 22a of the second header, and the upper side. The second heat exchange tube 32u is circulated. Further, the refrigerant is the lowermost first chamber 11z of the first header 10, the lowermost first heat exchange tube 31z, the lowermost chamber 20z of the second header, the lower second heat exchange tube 32z, and the lowermost part of the first header 10. The second room 12z is distributed. The flow paths of these refrigerants constitute a module. A plurality of modules are arranged in parallel in the heat exchanger 4.

The flow path of the refrigerant when the refrigeration cycle device 1 performs the defrosting operation will be described.
The refrigerant in the defrosting operation circulates in the opposite direction to that in the heating operation. When the refrigeration cycle device 1 shown in FIG. 1 performs a defrosting operation, the outdoor heat exchanger 4 functions as a condenser. At this time, the gaseous refrigerant flowing out from the compressor 2 through the four-way valve flows into the second refrigerant port 18 of the heat exchanger 4 shown in FIG.

The refrigerant flows from the second refrigerant ports 18a and 18z into the second chamber 12 of the first header 10 and the lowermost second chamber 12z. The refrigerant flows into the second heat exchange tube 32 from the second chamber 12 and the lowermost second chamber 12z. In the process of flowing through the second heat exchange tube 32, the refrigerant dissipates heat to the outside air. As a result, the gaseous refrigerant changes to a gas-liquid two-phase refrigerant having a large amount of gas-phase components. That is, a gas-liquid two-phase refrigerant having a large amount of gas-phase components flows through the second heat exchange tube 32.

The refrigerant flows from the second heat exchange tube 32 into the second chamber 22 and the lowermost chamber 20z of the second header 20. The refrigerant flows from the second chamber 22 through the connecting flow path 26 and flows into the first chamber 21.

The refrigerant flows into the first heat exchange tube 31 from the first chamber 21 and the lowermost chamber 20z of the second header 20. In the process of flowing through the first heat exchange tube 31, the refrigerant dissipates heat to the outside air. As a result, the gas-liquid two-phase refrigerant having a large amount of gas-phase components is changed to a gas-liquid two-phase refrigerant having a large amount of liquid-phase components. That is, a gas-liquid two-phase refrigerant having a large amount of liquid phase components flows through the first heat exchange tube 31.

The refrigerant flows from the first heat exchange tube 31 into the first chamber 11 of the first header 10. The refrigerant flows from the first chamber 11 into the first refrigerant port 17. The refrigerant flows out of the heat exchanger 4 from the first refrigerant port 17. The liquid refrigerant flowing out of the outdoor heat exchanger 4 shown in FIG. 1 flows into the expansion device 5.

As described above, in both the heating operation and the defrosting operation, the gas-liquid two-phase refrigerant having a large amount of liquid phase component flows through the first heat exchange tube 31, and the gas phase component is distributed through the second heat exchange tube 32. A large amount of gas-liquid two-phase refrigerant flows. That is, a gas-liquid two-phase refrigerant having a larger amount of liquid phase components than the second heat exchange tube 32 flows through the first heat exchange tube 31. A gas-liquid two-phase refrigerant having a larger gas phase component than the first heat exchange tube 31 flows through the second heat exchange tube 32.

During the defrosting operation, a gas-liquid two-phase refrigerant having a large amount of gas-phase components flows into the second heat exchange tube 32. In the process of flowing through the second heat exchange tube 32, the refrigerant dissipates heat to the outside air, so that the liquid phase component of the gas-liquid two-phase refrigerant increases. The upper second heat exchange tube 32u, which occupies most of the second heat exchange tube 32, is arranged above the first heat exchange tube 31. Therefore, the liquid phase component of the refrigerant flows from the upper second heat exchange tube 32u to the first heat exchange tube 31 according to gravity. As a result, it is possible to suppress a refrigerant shortage due to the retention of the refrigerant.

The defrosting method of the heat exchanger 4 of the embodiment will be described.
FIG. 7 is a flowchart of the defrosting method. The control unit 9 of the refrigeration cycle device 1 performs a heating operation (S02). The control unit 9 switches the four-way valve 3 to circulate the refrigerant 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.

When the refrigeration cycle device 1 performs the heating operation, the outdoor heat exchanger 4 functions as an evaporator. At this time, the refrigerant flowing through the heat exchange tube 30 absorbs heat from the outside air flowing through the outside air flow path. Therefore, dew condensation water adheres to the fins 40 and the heat exchange tube 30 that form the outside air flow path. Condensed water flows downward along the plate-shaped fins 40 and stays at the lowermost part of the heat exchanger 4. When the outside air temperature is low, the condensed water freezes and frost adheres. Therefore, frost tends to adhere to the lowermost part of the heat exchanger 4.

When frost is formed on the outside air flow path of the heat exchanger 4, it becomes difficult for the refrigerant to absorb heat from the outside air, and the heat exchange efficiency is lowered. When the temperature of the refrigerant is lower than that of the outside air, the refrigerant easily absorbs heat from the outside air, and the heat exchange efficiency is improved. Therefore, the control unit 9 lowers the temperature of the refrigerant by reducing the expansion device 5. When frost is formed on the outside air flow path of the heat exchanger 4, the refrigerant temperature drops to less than 0 ° C.
The control unit 9 determines whether the refrigerant temperature Te detected based on the signal from the temperature sensor 14 is less than 0 ° C. (S04).

When the determination in S04 is YES, the control unit 9 substitutes Te for Te0 (S06). The control unit 9 determines whether the difference ΔTe between the previously detected refrigerant temperature Te0 and the newly detected refrigerant temperature Te exceeds a predetermined value α (S08). The predetermined value α is set to, for example, 3 to 10 ° C. When the difference ΔTe exceeds the predetermined value α, the refrigerant temperature drops sharply. When frost is formed on the outside air flow path of the heat exchanger 4, the control unit 9 sharply lowers the refrigerant temperature.
If the determination in S08 is YES, the control unit 9 determines that the heat exchanger 4 has frosted (S10). At this time, the control unit 9 stops the operation of the compressor 2. The control unit 9 stops the operation of the blower fan 4a of the heat exchanger 4.

The control unit 9 performs a defrosting operation (S12). The control unit 9 switches the four-way valve to distribute the refrigerant 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. The control unit 9 starts the operation of the compressor 2. The control unit 9 does not operate the blower fan 4a.

In the defrosting operation, the high-temperature gaseous refrigerant flowing out of the compressor 2 flows into the second heat exchange tube 32 of the heat exchanger 4. The gaseous refrigerant dissipates heat in the process of flowing through the second heat exchange tube 32. The heat exchanger 4 of the embodiment has, as the second heat exchange tube 32, the lower second heat exchange tube 32z in addition to the upper second heat exchange tube 32u. The high-temperature gaseous refrigerant melts the frost adhering to the lowermost part of the heat exchanger 4 in the process of flowing through the lower second heat exchange tube 32z. Even when a large amount of frost is attached to the lowermost part of the heat exchanger 4, the lower second heat exchange tube 32z is arranged below the heat exchanger 4, so that efficient defrosting can be performed. As a result, defrosting can be completed in a short time defrosting operation. Since the water in which the frost has melted falls below the heat exchanger 4, reattachment of the frost is prevented.

The refrigerant that has flowed into the lower second heat exchange tube 32z flows into the lowermost first heat exchange tube 31z from the lowermost chamber 20z, and flows out from the lowermost first refrigerant port 17z. When the defrosting is completed, the temperature of the refrigerant flowing out from the lowermost first refrigerant port 17z rises. The control unit 9 determines whether the refrigerant temperature exceeds the predetermined value β (S14). The predetermined value β is set to, for example, 3 to 15 ° C. The temperature sensor 14 is connected to the lowermost first refrigerant port 17z below the first chamber 11 of the first header 10. Therefore, the control unit 9 can accurately determine the completion of defrosting at the lowermost part of the heat exchanger 4.
When the determination in S14 is YES, the control unit 9 determines that the defrosting is completed (S16). At this time, the control unit 9 stops the operation of the compressor 2.

The control unit 9 restarts the heating operation (S18). At this time, the control unit 9 switches the four-way valve 3 to circulate the refrigerant 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.
With the above, the processing of the defrosting method is completed.

As described in detail above, the heat exchanger 4 of the embodiment has a first header 10 and a second header 20, and a plurality of heat exchange tubes 30. The first header 10 and the second header 20 are formed in a tubular shape and are arranged side by side so as to be separated from each other in the X direction. 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 ends open inside the first header 10 and the second header 20. .. The plurality of heat exchange tubes 30 include a first heat exchange tube 31 and a second heat exchange tube 32. A gas-liquid two-phase refrigerant having a large amount of liquid phase components flows through the first heat exchange tube 31. The second heat exchange tube 32 communicates with the first heat exchange tube 31, and a gas-liquid two-phase refrigerant having a large amount of gas phase components flows. The second heat exchange tube 32 has an upper second heat exchange tube 32u and a lower second heat exchange tube 32z. The upper second heat exchange tube 32u is arranged above the first heat exchange tube 31. The lower second heat exchange tube 32z is arranged below the first heat exchange tube 31.

Frost tends to adhere to the lowermost part of the heat exchanger 4. A gas-liquid two-phase refrigerant having a large amount of gas-phase components flows through the second heat exchange tube 32. The second heat exchange tube 32 has a lower second heat exchange tube 32z. Therefore, the heat exchanger 4 can efficiently remove the frost adhering to the lowermost part. Therefore, defrosting can be completed in a short time defrosting operation.

The first header 10 and the second header 20 have a plurality of chambers divided in the Z direction. The second header 20 has a first chamber 21, a second chamber 22, and a lowermost chamber 20z as a plurality of chambers. The upper first heat exchange tube 31u, which is a part of the first heat exchange tube 31, opens in the first chamber 21. The second chamber 22 communicates with the first chamber 21 and the upper second heat exchange tube 32u opens. The lowermost chamber 20z is opened by both the lower second heat exchange tube 32z and the lowermost first heat exchange tube 31z, which is the first heat exchange tube 31 closest to the lower second heat exchange tube 32z.

Both the lower second heat exchange tube 32z and the lowermost first heat exchange tube 31z are opened in the lowermost chamber 20z. Therefore, a connection flow path for connecting the lower second heat exchange tube 32z and the lowermost first heat exchange tube 31z is unnecessary. As a result, the manufacturing cost of the heat exchanger 4 is suppressed.

The number of upper second heat exchange tubes 32u opening in the second chamber 22 of the second header 20 is larger than the number of upper first heat exchange tubes 31u opening in the first chamber 21 of the second header 20.
A gas-liquid two-phase refrigerant having a large amount of gas-phase components flows through the upper second heat exchange tube 32u. Since the number of the upper second heat exchange tubes 32u is larger than the number of the upper first heat exchange tubes 31u, the pressure loss in the flow process of the refrigerant is suppressed. On the other hand, a gas-liquid two-phase refrigerant having a large amount of liquid phase components flows through the upper first heat exchange tube 31u. At this time, only the gas phase component of the gas-liquid two-phase refrigerant may flow through the upper part of the heat exchange tube (gas escape), and the liquid phase component may stay in the lower part of the heat exchange tube (liquid pool). Since the number of the upper first heat exchange tubes 31u is smaller than the number of the upper second heat exchange tubes 32u, the flow path cross-sectional area of the upper first heat exchange tube 31u is small. Therefore, the gas-liquid two-phase refrigerant is integrally distributed in the upper first heat exchange tube 31u. As a result, the liquid pool is suppressed and the refrigerant circulates, so that the refrigerant shortage can be suppressed.

The refrigeration cycle device 1 includes a heat exchanger 4, a temperature sensor 14, and a control unit 9. The temperature sensor 14 is connected to the lowermost first refrigerant port 17z below the first chamber 11 where the first heat exchange tube 31 opens in the first header 10, and outputs a signal corresponding to the refrigerant temperature. The control unit 9 controls the defrosting operation based on the output signal of the temperature sensor 14.
When the defrosting of the frost adhering to the lowermost part of the heat exchanger 4 is completed, the temperature of the refrigerant flowing out from the first refrigerant port 17 below the first chamber 11 of the first header 10 rises. The temperature sensor 14 is connected to the lowermost lowermost first refrigerant port 17z of the first chamber 11. Therefore, the control unit 9 can accurately determine the completion of defrosting at the lowermost part of the heat exchanger 4 based on the output signal of the temperature sensor 14. Therefore, defrosting can be completed in a short time defrosting operation.

In the heat exchanger 4 of the first embodiment, the temperature sensor 14 is connected to the lowermost first refrigerant port 17z. During the defrosting operation, a high-temperature gaseous refrigerant flows into the lowermost second refrigerant port 18z adjacent to the lowermost first refrigerant port 17z. Therefore, the temperature sensor 14 connected to the lowermost first refrigerant port 17z may be affected by the refrigerant temperature of the lowermost second refrigerant port 18z. In this case, the temperature sensor 14 may be connected to the first refrigerant port 17a below (lower half) of the first chamber 11 of the first header 10, other than the lowermost first refrigerant port 17z. For example, the temperature sensor 14 may be connected to the first refrigerant port 17a of the adjacent first chamber 11a above the lowermost first chamber 11z. As a result, the temperature sensor 14 is less affected by the refrigerant temperature of the lowermost second refrigerant port 18z.

(Second Embodiment)
FIG. 8 is a schematic configuration diagram of the heat exchanger 204 of the second embodiment. The heat exchanger 204 of the second embodiment shown in FIG. 8 differs from the heat exchanger 4 of the first embodiment shown in FIG. 5 in that it has a connecting flow path 19. Of the configurations of the second embodiment, configurations other than the configurations described below are the same as the configurations of the first embodiment.

The connecting flow path 19 communicates the lowermost second chamber 12z of the first header 10 with the second chamber 12. The connecting flow path 19 is connected below the second chamber 12.
The lubricating oil (compressor oil) of the compressor 2 is mixed with the refrigerant flowing through the refrigeration cycle device 1. In the heating operation, the gas-phase component of the gas-liquid two-phase refrigerant increases in the process of flowing through the upper second heat exchange tube 32u. When the gaseous refrigerant flows into the second chamber 12 from the upper second heat exchange tube 32u, the liquid compressor oil mixed in the refrigerant falls below the second chamber 12 and stays there. Therefore, there is a possibility that the compressor 2 will run out of compressor oil.

The heat exchanger 204 of the second embodiment has a connecting flow path 19 that communicates the lowermost second chamber 12z of the first header 10 with the lower part of the second chamber 12. As a result, the gaseous refrigerant flowing out of the lowermost second chamber 12z flows through the connecting flow path 19 and flows into the lower part of the second chamber 12. At this time, the gaseous refrigerant blows up the compressor oil that stays below the second chamber 12 and flows out from the second refrigerant port 18. As a result, the compressor oil returns to the compressor, so that the shortage of the compressor oil in the compressor 2 can be suppressed.

The heat exchanger 4 of the above-described embodiment has a configuration in which the refrigerant flows into the first header 10, is folded back at the second header 20, and flows out from the first header 10. On the other hand, the heat exchanger may be configured such that the refrigerant folds back a plurality of times at each header.
The heat exchanger 4 of the embodiment has a configuration in which the same number of upper second heat exchange tubes are opened to each of the plurality of second chambers 22a formed in the second header 20. On the other hand, the heat exchanger may have a configuration in which different numbers of upper second heat exchange tubes are opened to the plurality of second chambers 22a.

According to at least one embodiment described above, the heat exchanger 4 has a second heat exchange tube 32 through which a gas-liquid two-phase refrigerant having a large amount of gas phase components flows. The second heat exchange tube 32 has a lower second heat exchange tube 32z arranged below the first heat exchange tube 31. As a result, defrosting can be completed in a short time defrosting operation.

Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... Refrigeration cycle device, 4 ... Heat exchanger, 9 ... Control unit, 10 ... 1st header, 11 ... 1st room, 12 ... 2nd room, 12z ... Lowermost 2nd room, 14 ... Temperature sensor, 17 ... 1st refrigerant port (refrigerant inlet / outlet), 20 ... second header, 20z ... lowermost chamber, 21 ... first chamber, 22 ... second chamber, 30 ... heat exchange tube, 31 ... first heat exchange tube, 31u ... upper 1st heat exchange tube (some first heat exchange tubes), 31z ... Lowermost 1st heat exchange tube, 32 ... 2nd heat exchange tube, 32u ... Upper 2nd heat exchange tube, 32z ... Lower 2nd heat exchange tube.

Claims (5)

A first header and a second header formed in a tubular shape and arranged side by side at a distance from each other,
It has 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 both ends open inside the first header and the second header.
The plurality of heat exchange tubes are a first heat exchange tube through which a gas-liquid two-phase refrigerant having a large amount of liquid phase components flows, and a second heat exchange tube in which a gas-liquid two-phase refrigerant having a large amount of gas phase components flows through the first heat exchange tube. With a heat exchange tube,
The second heat exchange tube has an upper second heat exchange tube arranged above the first heat exchange tube and a lower second heat exchange tube arranged below the first heat exchange tube. ,
Heat exchanger. The first header and the second header have a plurality of chambers divided in the central axis direction.
The second header has, as the plurality of chambers, a first chamber in which a part of the first heat exchange tubes opens, and a second chamber in which the upper second heat exchange tube opens in communication with the first chamber. It has a lowermost chamber in which both the lower second heat exchange tube and the first heat exchange tube closest to the lower second heat exchange tube are open.
The heat exchanger according to claim 1. The number of the upper second heat exchange tubes opened in the second chamber of the second header is larger than the number of the first heat exchange tubes opened in the first chamber of the second header.
The heat exchanger according to claim 2. The first header has a first chamber opened by the first heat exchange tube, a second chamber opened by the upper second heat exchange tube, and an opening of the lower second heat exchange tube as the plurality of chambers. Has the lowest second chamber and
The lowermost second chamber of the first header communicates below the second chamber of the first header.
The heat exchanger according to claim 2 or 3. The heat exchanger according to any one of claims 1 to 4.
A temperature sensor, which is arranged at a refrigerant inlet / outlet below the first chamber in which the first heat exchange tube opens in the first header and outputs a signal corresponding to the refrigerant temperature,
It has a control unit that controls defrosting operation based on the output signal of the temperature sensor.
Refrigeration cycle equipment.

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