Heat exchanger and air conditioner

Abstract

To provide a heat exchanger capable of appropriately grasping a temperature of a coolant passing a lower side of the heat exchanger, and an air conditioning device.SOLUTION: A heat exchanger comprises: a plurality of flat tubes 28 including a first flat tube 28x, and a second flat tube 28y which is disposed at an upper side of the first flat tube 28x; a liquid header 60 to which the plurality of flat tubes 28 is connected; a liquid coolant connection pipe 20a which is connected to the liquid header 60; and a temperature sensor 80. The liquid header 60 includes: a confluent channel C extending from a connection portion of the liquid coolant connection pipe 20a; a first coolant channel A connecting a connection portion of the first flat tube 28x with the confluent channel C; and a second coolant channel B connecting a connection portion of the second flat tube 28y with the confluent channel C. The temperature sensor 80 detects a temperature of a coolant flowing in the first coolant channel A.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to a heat exchanger and an air conditioner.

Background Art

[0002] Conventionally, in an air conditioner, during heating operation, when frost adheres to an outdoor heat exchanger through which a refrigerant that is colder than the outside air flows, a defrosting operation is performed to melt the frost by supplying gas refrigerant to the outdoor heat exchanger. This defrosting operation ends when the frost adhering to the heat exchanger is removed.

[0003] For example, in the air conditioner described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-088005), it is proposed to determine the end timing of the defrosting operation using the temperature of the refrigerant that has passed through the outdoor heat exchanger.

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] During the defrosting operation, the refrigerant that is supplied to the heat exchanger and condensed tends to stay in the lower region of the heat exchanger, and the refrigerant flow rate in the lower region of the heat exchanger tends to decrease. For this reason, the melting of the frost adhering to the lower part of the heat exchanger is likely to occur at the end of the defrosting operation. Therefore, if the temperature of the refrigerant flowing below the heat exchanger can be grasped, it becomes possible to appropriately grasp the end timing of the defrosting operation.

[0005] On the other hand, in the air conditioner described in Patent Document 1, during the defrosting operation, the temperature of the refrigerant in which the refrigerant flowing below the heat exchanger and the refrigerant flowing above the heat exchanger are mixed is used to determine the end timing of the defrosting operation. For this reason, it is difficult to appropriately grasp the end timing of the defrosting operation.

[0006] From the above, in a heat exchanger in which the refrigerant flowing through a plurality of heat transfer tubes merges at a header, it is desirable to appropriately grasp the temperature of the refrigerant flowing below the heat exchanger.

Means for Solving the Problems

[0007] The heat exchanger according to the first aspect includes a plurality of heat transfer tubes, a header, a refrigerant pipe, and a temperature sensor. The plurality of heat transfer tubes include a first heat transfer tube and a second heat transfer tube. The second heat transfer tube is disposed above the first heat transfer tube. The header is connected to the plurality of heat transfer tubes. The refrigerant pipe is connected to the header. The header has a confluence flow path, a first refrigerant flow path, and a second refrigerant flow path. The confluence flow path extends from the connection portion of the refrigerant pipe. The first refrigerant flow path connects the connection portion of the first heat transfer tube and the confluence flow path. The second refrigerant flow path connects the connection portion of the second heat transfer tube and the confluence flow path. The temperature sensor detects the temperature of the refrigerant flowing through the first refrigerant flow path.

[0008] In this heat exchanger, when frost adheres due to being used in an air conditioner and defrosting is performed, the temperature sensor can detect the temperature of the refrigerant flowing through the first refrigerant flow path from the first heat transfer tube located below the second heat transfer tube to the confluence flow path in the header. Therefore, it becomes possible to appropriately grasp the temperature of the refrigerant flowing below the heat exchanger.

[0009] The heat exchanger according to the second aspect is the heat exchanger of the first aspect, and the detection position of the temperature sensor is closer to the first refrigerant flow path than the second refrigerant flow path and closer to the first refrigerant flow path than the refrigerant pipe.

[0010] In this heat exchanger, when detecting the temperature of the refrigerant that has passed below the heat exchanger, it becomes possible to greatly suppress the influence of the temperature of the refrigerant flowing through the second refrigerant flow path and the refrigerant flowing through the refrigerant pipe.

[0011] The heat exchanger according to the third aspect is the heat exchanger of the first aspect or the second aspect, and the first heat transfer tube includes the portion located at the lowest position among the plurality of heat transfer tubes.

[0012] In this heat exchanger, it is easy to grasp the timing when all the frost adhering to the heat exchanger has melted.

[0013] The heat exchanger according to the fourth aspect is any one of the heat exchangers according to the first to third aspects, and the header has an outer wall portion. The outer wall portion is located on the side opposite to the side where the connection portion between the heat transfer tubes and the header in the header is located. The first refrigerant flow path has a first piping portion. The first piping portion is located on the side opposite to the side where the connection portion between the heat transfer tubes and the header is located with respect to the outer wall portion.

[0014] In this heat exchanger, a location where it is easy to grasp the temperature of the refrigerant flowing below the heat exchanger can be created.

[0015] The heat exchanger according to the fifth aspect is the heat exchanger according to the fourth aspect, and the temperature sensor detects the temperature of the refrigerant flowing through the first piping portion.

[0016] In this heat exchanger, the detection accuracy of the temperature of the refrigerant that has passed below the heat exchanger can be improved.

[0017] The heat exchanger according to the sixth aspect is the heat exchanger according to the fifth aspect, and the temperature sensor detects the temperature of the refrigerant flowing through the portion to be detected in the first piping portion. The portion to be detected is the portion where the refrigerant flows in the vertical direction.

[0018] In this heat exchanger, it is possible to greatly suppress the detection error of the temperature sensor caused by the flow direction of the refrigerant.

[0019] The heat exchanger according to the seventh aspect is any one of the heat exchangers according to the fourth to sixth aspects, and the second refrigerant flow path has a second piping portion. The second piping portion is located on the side opposite to the side where the connection portion between the heat transfer tubes and the header is located with respect to the outer wall portion.

[0020] In this heat exchanger, it is easy to adjust the flow distribution state of the refrigerant between the first refrigerant flow path and the second refrigerant flow path.

[0021] The heat exchanger according to the eighth aspect is the heat exchanger according to the seventh aspect, and the lengths of the first piping portion and the second piping portion are equal.

[0022] In this heat exchanger, it is easier to adjust the refrigerant flow distribution state between the first refrigerant flow path and the second refrigerant flow path.

[0023] The heat exchanger according to the ninth aspect is the heat exchanger according to the seventh or eighth aspect, and the lower end of the first piping section is located below the lower end of the second piping section.

[0024] In this heat exchanger, since the first refrigerant flow path is connected to the first heat transfer tube located below the second heat transfer tube, such a structure can be easily obtained.

[0025] The heat exchanger according to the tenth aspect is the heat exchanger according to any one of the first to third aspects, and the header has an outer wall portion. The outer wall portion is located on the side opposite to the side where the connection portion between the heat transfer tube and the header in the header is located. The outer wall portion includes a first protruding portion protruding toward the side opposite to the side where the connection portion between the heat transfer tube and the header is located. The first refrigerant flow path includes a portion through which the refrigerant flows along the first protruding portion on the side of the outer wall portion where the connection portion between the heat transfer tube and the header is located.

[0026] In this heat exchanger, it is possible to create a location where it is easy to grasp the temperature of the refrigerant flowing below the heat exchanger.

[0027] The heat exchanger according to the eleventh aspect is the heat exchanger according to the tenth aspect, and the temperature sensor detects the temperature of the refrigerant flowing along the first protruding portion.

[0028] In this heat exchanger, it is possible to improve the detection accuracy of the temperature of the refrigerant that has passed below the heat exchanger.

[0029] The heat exchanger according to the twelfth aspect is the heat exchanger according to the eleventh aspect, and the temperature sensor detects the temperature of the refrigerant flowing through the detected portion of the first protruding portion. The detected portion is a portion through which the refrigerant flows in the vertical direction.

[0030] In this heat exchanger, it is possible to significantly reduce the detection error of the temperature sensor caused by the flow direction of the refrigerant.

[0031] The heat exchanger according to the 13th aspect is any one of the heat exchangers according to the 10th to 12th aspects, and the outer wall portion includes a second protruding portion. The second protruding portion protrudes toward the side opposite to the side where the connection portion between the heat transfer tube and the header is located. The second refrigerant flow path includes a portion through which the refrigerant flows along the second protruding portion on the side of the outer wall portion where the connection portion between the heat transfer tube and the header is located.

[0032] In this heat exchanger, it is easy to adjust the flow splitting state of the refrigerant between the first refrigerant flow path and the second refrigerant flow path.

[0033] The heat exchanger according to the 14th aspect is the heat exchanger according to the 13th aspect, and the flow path length of the first protruding portion in the first refrigerant flow path is equal to the flow path length of the second protruding portion in the second refrigerant flow path.

[0034] In this heat exchanger, it is even easier to adjust the flow splitting state of the refrigerant between the first refrigerant flow path and the second refrigerant flow path.

[0035] The heat exchanger according to the 15th aspect is any one of the heat exchangers according to the 13th to 14th aspects, and the lower end of the first protruding portion is located below the lower end of the second protruding portion.

[0036] In this heat exchanger, since the first refrigerant flow path is connected to the first heat transfer tube located below the second heat transfer tube, such a structure can be easily obtained.

[0037] The heat exchanger according to the 16th aspect is any one of the heat exchangers according to the 1st to 15th aspects, and the header has a plate-like member. The plate-like member has an opening penetrating in the plate thickness direction. The opening constitutes a part of the confluence flow path, a part of the first refrigerant flow path, and a part of the second refrigerant flow path.

[0038] In this heat exchanger, the opening formed in the plate-like member can create a refrigerant flow path in which the first refrigerant flow path and the second refrigerant flow path merge into the confluence flow path.

[0039] The air conditioner according to the 17th aspect includes any one of the heat exchangers from the 1st aspect to the 16th aspect and a control unit. The control unit can switch between an operation in which the heat exchanger functions as an evaporator of the refrigerant and a defrost operation for defrosting the heat exchanger. The control unit performs the defrost operation based on the detected temperature of the temperature sensor.

[0040] In this air conditioner, when the frost adhering to the heat exchanger melts, it becomes possible to end the defrost operation and start the operation in which the heat exchanger functions as an evaporator of the refrigerant.

[0041] The air conditioner according to the 18th aspect is the air conditioner according to the 17th aspect, and the control unit ends the defrost operation based on the temperature detected by the temperature sensor.

[0042] In this air conditioner, it becomes possible to end the defrost operation early after the melting of the frost adhering to the heat exchanger is completed.

[0043] The air conditioner according to the 19th aspect is the air conditioner according to either the 17th aspect or the 18th aspect, and has an outdoor unit. The outdoor unit includes a heat exchanger.

[0044] In this air conditioner, it becomes possible to appropriately grasp the timing when the melting of the frost is completed during the defrost operation in the heat exchanger provided in the outdoor unit.

Brief Description of the Drawings

[0045]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0046] Hereinafter, embodiments of the heat exchanger of the present disclosure and an air conditioner employing the heat exchanger will be described.

[0047] (1) Configuration of the air conditioner The air conditioner 1 will be described with reference to the drawings.

[0048] FIG. 1 is a schematic configuration diagram of an air conditioner 1 having a heat exchanger according to an embodiment of the present disclosure as an outdoor heat exchanger 11.

[0049] The air conditioner 1 is a device that performs cooling and heating of an air-conditioned space by performing a vapor compression refrigeration cycle. The air-conditioned space is, for example, a space inside a building such as an office building, a commercial facility, or a residence. Note that the air conditioner is merely an example of a refrigerant cycle device, and the heat exchanger of the present disclosure may be used in other refrigerant cycle devices, such as a refrigerator, a freezer, a water heater, a floor heating device, etc.

[0050] As shown in FIG. 1, the air conditioner 1 mainly includes an outdoor unit 2, an indoor unit 9, a liquid refrigerant connection pipe 4 and a gas refrigerant connection pipe 5, and a control unit 3 that controls the devices constituting the outdoor unit 2 and the indoor unit 9. The liquid refrigerant connection pipe 4 and the gas refrigerant connection pipe 5 are refrigerant connection pipes that connect the outdoor unit 2 and the indoor unit 9. In the air conditioner 1, the outdoor unit 2 and the indoor unit 9 are connected via the liquid refrigerant connection pipe 4 and the gas refrigerant connection pipe 5, thereby constituting a refrigerant circuit 6.

[0051] Note that in FIG. 1, the air conditioner 1 has one indoor unit 9. However, the air conditioner 1 may have a plurality of indoor units 9 that are connected to the outdoor unit 2 in parallel with each other by the liquid refrigerant connecting pipe 4 and the gas refrigerant connecting pipe 5. Further, the air conditioner 1 may have a plurality of outdoor units 2. Additionally, the air conditioner 1 may be an integrated air conditioner in which the outdoor unit 2 and the indoor unit 9 are integrally formed.

[0052] (1-1) Outdoor unit The outdoor unit 2 is installed outside the air-conditioned space, for example, on the rooftop of a building or near the wall surface of a building.

[0053] The outdoor unit 2 mainly has an accumulator 7, a compressor 8, a four-way switching valve 10, an outdoor heat exchanger 11, an outdoor expansion valve 12, a liquid-side shutoff valve 13, a gas-side shutoff valve 14, and an outdoor fan 16.

[0054] As refrigerant pipes for connecting various devices constituting the refrigerant circuit 6, the outdoor unit 2 mainly has a suction pipe 17, a discharge pipe 18, a first gas refrigerant pipe 19, a liquid refrigerant pipe 20, and a second gas refrigerant pipe 21. The suction pipe 17 connects the four-way switching valve 10 and the suction side of the compressor 8. The accumulator 7 is provided on the suction pipe 17. The discharge pipe 18 connects the discharge side of the compressor 8 and the four-way switching valve 10. The first gas refrigerant pipe 19 connects the four-way switching valve 10 and the gas side of the outdoor heat exchanger 11. The liquid refrigerant pipe 20 connects the liquid side of the outdoor heat exchanger 11 and the liquid-side shutoff valve 13. The outdoor expansion valve 12 is provided on the liquid refrigerant pipe 20. The second gas refrigerant pipe 21 connects the four-way switching valve 10 and the gas-side shutoff valve 14.

[0055] The compressor 8 is a device that sucks low-pressure refrigerant in the refrigeration cycle from the suction pipe 17, compresses the refrigerant with a compression mechanism (not shown), and discharges the compressed refrigerant to the discharge pipe 18.

[0056] The four-way switching valve 10 is a mechanism that changes the state of the refrigerant circuit 6 between the cooling operation state and the heating operation state by switching the flow direction of the refrigerant. When the refrigerant circuit 6 is in the cooling operation state, the outdoor heat exchanger 11 functions as a radiator or condenser for the refrigerant, and the indoor heat exchanger 91 functions as an evaporator for the refrigerant. When the refrigerant circuit 6 is in the heating operation state, the outdoor heat exchanger 11 functions as an evaporator for the refrigerant, and the indoor heat exchanger 91 functions as a condenser for the refrigerant. When the four-way switching valve 10 sets the state of the refrigerant circuit 6 to the cooling operation state, the four-way switching valve 10 connects the suction pipe 17 to the second gas refrigerant pipe 21 and connects the discharge pipe 18 to the first gas refrigerant pipe 19 (see the solid line in the four-way switching valve 10 in FIG. 1). When the four-way switching valve 10 sets the state of the refrigerant circuit 6 to the heating operation state, the four-way switching valve 10 connects the suction pipe 17 to the first gas refrigerant pipe 19 and connects the discharge pipe 18 to the second gas refrigerant pipe 21 (see the broken line in the four-way switching valve 10 in FIG. 1).

[0057] The outdoor heat exchanger 11 is a device that causes heat exchange between the refrigerant flowing inside and the air at the installation location of the outdoor unit 2. Details of the outdoor heat exchanger 11 will be described later.

[0058] The outdoor expansion valve 12 is disposed between the outdoor heat exchanger 11 and the indoor heat exchanger 91 in the refrigerant circuit 6. In the present embodiment, the outdoor expansion valve 12 is disposed in the liquid refrigerant pipe 20 between the outdoor heat exchanger 11 and the liquid-side shutoff valve 13. The outdoor expansion valve 12 has a mechanism for adjusting the pressure and flow rate of the refrigerant flowing through the liquid refrigerant pipe 20.

[0059] The accumulator 7 is a container having a gas-liquid separation function for separating the incoming refrigerant into gas refrigerant and liquid refrigerant. Further, the accumulator 7 is a container having a function of storing surplus refrigerant generated according to fluctuations in the operating load and the like.

[0060] The liquid-side shutoff valve 13 is a valve provided at the connection portion between the liquid refrigerant pipe 20 and the liquid refrigerant communication pipe 4. The gas-side shutoff valve 14 is a valve provided at the connection portion between the second gas refrigerant pipe 21 and the gas refrigerant communication pipe 5. The liquid-side shutoff valve 13 and the gas-side shutoff valve 14 are open during the operation of the air conditioner 1.

[0061] The outdoor fan 16 is a fan for sucking external heat source air into the casing of the outdoor unit 2 (not shown) and supplying it to the outdoor heat exchanger 11, and discharging the air that has exchanged heat with the refrigerant in the outdoor heat exchanger 11 outside the casing of the outdoor unit 2. The outdoor fan 16 is, for example, a propeller fan.

[0062] (1-2) Indoor unit The indoor unit 9 is a unit installed in the space to be air-conditioned. The indoor unit 9 is, for example, a ceiling-embedded unit, but may also be a ceiling-suspended type, wall-mounted type, or floor-standing type unit. Further, the indoor unit 9 may be installed outside the space to be air-conditioned. For example, the indoor unit 9 may be installed in the attic, machine room, garage, etc. In this case, an air passage for supplying the air that has exchanged heat with the refrigerant in the indoor heat exchanger 91 from the indoor unit 9 to the space to be air-conditioned is installed. The air passage is, for example, a duct.

[0063] The indoor unit 9 mainly includes an indoor heat exchanger 91, an indoor expansion valve 93, and an indoor fan 92.

[0064] In the indoor heat exchanger 91, heat exchange is performed between the refrigerant flowing through the indoor heat exchanger 91 and the air in the space to be air-conditioned. The indoor heat exchanger 91 is, for example, a fin-and-tube type heat exchanger having a plurality of heat transfer tubes (not shown) and fins. One end of the indoor heat exchanger 91 is connected to the indoor expansion valve 93 via a refrigerant pipe. The other end of the indoor heat exchanger 91 is connected to the gas refrigerant communication pipe 5 via a refrigerant pipe.

[0065] The indoor expansion valve 93 is disposed between the indoor heat exchanger 91 and the liquid refrigerant communication pipe 4 in the refrigerant circuit 6. The indoor expansion valve 93 has a mechanism for adjusting the pressure and flow rate of the refrigerant passing through the indoor expansion valve 93.

[0066] The indoor fan 92 is a mechanism that sucks in the air in the air-conditioned space into the casing (not shown) of the indoor unit 9 and supplies it to the indoor heat exchanger 91, and blows out the air that has exchanged heat with the refrigerant in the indoor heat exchanger 91 into the air-conditioned space. The indoor fan 92 is, for example, a turbo fan.

[0067] (1-3) Control unit The control unit 3 is a functional unit that controls the operations of various devices constituting the air conditioner 1.

[0068] The control unit 3 is configured such that, for example, an outdoor control unit (not shown) of the outdoor unit 2 and an indoor control unit (not shown) of the indoor unit 9 are communicably connected via a transmission line (not shown). The outdoor control unit and the indoor control unit are units having, for example, a processor such as a CPU (Central Processing Unit), and a memory such as a ROM and a RAM in which various programs for controlling the air conditioner 1 that can be executed by the processor are stored, such as a microcomputer. In FIG. 1, for the sake of convenience, the control unit 3 is drawn at a position separated from the outdoor unit 2 and the indoor unit 9.

[0069] The control unit 3 is electrically connected to various devices of the outdoor unit 2 and the indoor unit 9, including the compressor 8, the four-way switching valve 10, the outdoor expansion valve 12, the outdoor fan 16, the indoor fan 92, and the indoor expansion valve 93. The control unit 3 is also electrically connected to various sensors (not shown) provided in the outdoor unit 2 and the indoor unit 9. The control unit 3 is communicably configured with a remote control (not shown) operated by the user of the air conditioner 1.

[0070] The control unit 3 controls the operation and stop of the air conditioner 1 and the operations of various devices constituting the air conditioner 1 based on the measurement signals of various sensors and commands received from a remote control (not shown).

[0071] (2) Configuration of the outdoor heat exchanger The configuration of the outdoor heat exchanger 11 will be described with reference to the drawings.

[0072] FIG. 2 is a schematic perspective view of the outdoor heat exchanger 11. FIG. 3 is a partially enlarged view of the outdoor heat exchanger 11 of a heat exchange section 27 described later. FIG. 4 is a schematic view showing an attachment state of a fin 29 described later to a flat tube 28 in the heat exchange section 27. FIG. 5 is a schematic configuration diagram of the outdoor heat exchanger 11. The arrow of the heat exchange section 27 shown in FIG. 5 indicates the flow of the refrigerant during the heating operation (when the outdoor heat exchanger 11 functions as an evaporator). FIG. 6 shows an external perspective view of the inlet / outlet header 40.

[0073] In the following description, in order to explain the direction and position, expressions such as "up", "down", "left", "right", "front (front surface)", "rear (rear surface)" may be used. Unless otherwise specified, these expressions follow the direction of the arrow drawn in FIG. 2. Note that these expressions representing the direction and position are used for convenience of explanation, and do not specify the direction and position of the entire outdoor heat exchanger 11 or each component of the outdoor heat exchanger 11 to the direction and position of the expression in the description without special note.

[0074] The outdoor heat exchanger 11 is a device that performs heat exchange between the refrigerant flowing inside and the air.

[0075] The outdoor heat exchanger 11 mainly includes a plurality of flat tubes 28, a plurality of fins 29, a folding header 30, and an inlet / outlet header 40. In the present embodiment, the flat tube 28, the fin 29, the folding header 30, and the inlet / outlet header 40 are all made of aluminum or an aluminum alloy.

[0076] The flat tube 28 and the fin 29 fixed to the flat tube 28 form the heat exchange section 27. In the outdoor heat exchanger 11, heat exchange is performed between the refrigerant flowing through the flat tube 28 and the air flowing through the ventilation path formed by the flat tube 28 and the fin 29 in the heat exchange section 27 when air flows through the ventilation path.

[0077] (2-1) Flat Tube The flat tube 28 is a flat heat transfer tube having flat surfaces 28a serving as heat transfer surfaces at the top and bottom as shown in FIG. 3. A plurality of refrigerant passages 28b through which refrigerant flows are formed in the flat tube 28 as shown in FIG. 3. For example, the flat tube 28 is a flat multi-hole tube in which a large number of refrigerant passages 28b having a small cross-sectional area through which refrigerant flows are formed. In the present embodiment, these plurality of refrigerant passages 28b are provided side by side in the air flow direction.

[0078] In the outdoor heat exchanger 11, as shown in FIG. 5, a plurality of flat tubes 28 extending horizontally between the folded header 30 side and the inlet / outlet header 40 side are arranged in a plurality of vertically stacked rows.

[0079] In the present embodiment, the flat tube 28 extending between the folded header 30 side and the inlet / outlet header 40 side is bent at one location, and the heat exchange portion 27 formed by the flat tube 28 is formed in a substantially L shape in plan view. In the present embodiment, the plurality of flat tubes 28 are arranged at regular intervals vertically.

[0080] When the outdoor fan 16 is driven, an air flow passing through the main surface of the outdoor heat exchanger 11 from the rear to the front and an air flow passing through the left side surface portion of the outdoor heat exchanger 11 from the left to the right are generated.

[0081] (2-2) Fins The plurality of fins 29 are members for increasing the heat transfer area of the outdoor heat exchanger 11. Each fin 29 is a plate-like member extending in the row direction in which the flat tubes 28 are arranged. The outdoor heat exchanger 11 is used in a mode in which a plurality of flat tubes 28 extending in the horizontal direction are arranged side by side in the vertical direction. Therefore, in a state where the outdoor heat exchanger 11 is installed in the outdoor unit 2, each fin 29 extends in the vertical direction.

[0082] Each fin 29 is formed with a plurality of notches 29a extending along the insertion direction of the flat tube 28 as shown in FIG. 4 so that a plurality of flat tubes 28 can be inserted therein. The notches 29a extend in the extending direction of the fin 29 and in a direction orthogonal to the thickness direction of the fin 29. In a state where the outdoor heat exchanger 11 is installed in the outdoor unit 2, the notches 29a formed in each fin 29 extend in the horizontal direction. The notches 29a are formed in the fin 29 with an interval corresponding to the arrangement interval of the flat tubes 28. In the outdoor heat exchanger 11, the plurality of fins 29 are arranged side by side along the extending direction of the flat tubes 28. By inserting the flat tubes 28 into the respective notches 29a of the plurality of fins 29, the space between adjacent flat tubes 28 is partitioned into a plurality of ventilation paths through which air flows.

[0083] Each fin 29 has a communication portion 29b that communicates vertically on the upstream or downstream side of the flat tube 28 in the air flow direction. In the present embodiment, the communication portion 29b of the fin 29 is located on the upwind side of the flat tube 28.

[0084] (2-3) Inlet / Outlet Header As shown in FIGS. 5 and 6, the inlet / outlet header 40 has an upper gas header 50 and a lower liquid header 60. The gas header 50 and the liquid header 60 are vertically partitioned by a partition plate 41. The gas header 50 has a space inside, and the liquid header 60 has a space isolated from the space inside the gas header 50 by the partition plate 41. The upper end of the gas header 50 is closed by an upper lid 42. The partition plate 41 also functions as the bottom plate of the gas header 50.

[0085] A gas refrigerant connection pipe 19a that constitutes one end of the first gas refrigerant pipe 19 is connected to the liquid header 60.

[0086] A liquid refrigerant connection pipe 20a that constitutes one end of the liquid refrigerant pipe 20 is connected to the gas header 50.

[0087] As shown in Fig. 5, one end of each flat tube 28 is connected to the folding header 30, and the other end of each flat tube 28 is connected to the gas header 50 and the liquid header 60 of the inlet / outlet header 40. The outdoor heat exchanger 11 is arranged in a casing (not shown) of the outdoor unit 2 such that the longitudinal directions of the folding header 30 and the inlet / outlet header 40 generally coincide with the vertical direction.

[0088] (2-4) Folding header Connected to the folding header 30 are the ends of the flat tubes 28 different from the ends of the flat tubes 28 connected to the gas header 50 and the liquid header 60 of the inlet / outlet header 40.

[0089] The outdoor heat exchanger 11 has a first flow path group X, a second flow path group Y, and a third flow path group Z arranged vertically. In the outdoor heat exchanger 11, the flat tubes 28 arranged vertically belong to any one of the plurality of flow path groups X, Y, and Z. The first flow path group X is the flow path group located at the lowest position and to which a plurality of first flat tubes 28x belong. The second flow path group Y is a flow path group located above the first flow path group X and below the third flow path group Z and to which a plurality of second flat tubes 28y belong. The third flow path group Z is the flow path group located at the highest position and to which a plurality of third flat tubes 28z belong.

[0090] (3) Refrigerant flow in each operation and the outdoor heat exchanger The control unit 3 receives the detection information of various sensors or commands from a remote control or the like, and switches and executes a cooling operation, a heating operation, a defrosting operation, etc.

[0091] When the air conditioner 1 performs a heating operation, the control unit 3 switches the connection state of the four-way switching valve 10 to the state shown by the broken line in Fig. 1 and operates the compressor 8. The refrigerant discharged from the compressor 8 condenses by exchanging heat with the indoor air in the indoor heat exchanger 91, is decompressed in the indoor expansion valve 93 or the outdoor expansion valve 12, and then is sent to the outdoor heat exchanger 11. The refrigerant sent to the outdoor heat exchanger 11 evaporates by exchanging heat with the outside air and is inhaled into the compressor 8 again.

[0092] As described above, when the outdoor heat exchanger 11 functions as an evaporator of the refrigerant during the heating operation, the refrigerant in a liquid state or a liquid-vapor two-phase state that has reached the liquid header 60 from the liquid refrigerant pipe 20 is divided into the refrigerant flowing through the first flow path group X and the refrigerant flowing through the second flow path group Y in the internal space of the liquid header 60. Then, the divided refrigerant flows through a plurality of first flat tubes 28x belonging to the first flow path group X and a plurality of second flat tubes 28y belonging to the second flow path group Y, respectively. The refrigerant flowing through the plurality of first flat tubes 28x and the second flat tubes 28y partially evaporates by exchanging heat with the air and reaches the lower region in the internal space of the return header 30. The refrigerant sent to the lower region in the internal space of the return header 30 is sent to the upper region in the internal space of the return header 30. The refrigerant reaching the upper region of the return header 30 flows through a plurality of third flat tubes 28z belonging to the third flow path group Z connected to the upper region of the return header 30. The refrigerant flowing through the plurality of third flat tubes 28z further evaporates by exchanging heat with the air again and reaches the gas header 50. The refrigerant reaching the gas header 50 merges and then flows through the first gas refrigerant pipe 19.

[0093] When the air conditioner 1 performs a cooling operation, the control unit 3 switches the connection state of the four-way switching valve 10 to the state shown by the solid line in FIG. 1 and operates the compressor 8. The refrigerant discharged from the compressor 8 condenses by exchanging heat with the outside air in the outdoor heat exchanger 11, is depressurized in the outdoor expansion valve 12 or the indoor expansion valve 93, and then is sent to the indoor heat exchanger 91. The refrigerant sent to the indoor heat exchanger 91 evaporates by exchanging heat with the indoor air and is inhaled into the compressor 8 again.

[0094] In addition, when the air conditioner 1 is performing a heating operation and a predetermined defrost start condition is satisfied, the control unit 3 switches the connection state of the four-way switching valve 10 to the state shown by the solid line in FIG. 1 and operates the compressor 8 to perform a defrost operation of supplying the discharged refrigerant at high temperature and high pressure to the outdoor heat exchanger 11. By this defrost operation, the frost adhering to the outdoor heat exchanger 11 melts. The predetermined defrost start condition is not particularly limited, and for example, it can be a case where the outside air temperature is equal to or lower than a predetermined temperature for a predetermined time or more. Further, the defrost operation ends when a predetermined defrost end condition is satisfied, and the heating operation is restarted by switching the connection state of the four-way switching valve 10 to the state shown by the broken line in FIG. 1 and operating the compressor 8. The predetermined defrost end condition is a condition determined based on the detection value of the temperature sensor 80 described later, and for example, it may be a condition satisfied when the state where the detection value of the temperature sensor 80 is equal to or higher than a predetermined temperature continues for a predetermined time or more. Note that the defrost start condition and the defrost end condition are determined by the control unit 3.

[0095] When the outdoor heat exchanger 11 functions as a condenser of the refrigerant during the cooling operation or the defrosting operation in this way, the refrigerant discharged from the compressor 8 flows through the first gas refrigerant pipe 19 and then flows into the gas header 50. The gaseous refrigerant that has reached the gas header 50 is branched in the internal space of the gas header 50 and then flows through a plurality of third flat tubes 28z belonging to the third flow path group Z connected to the gas header 50. The refrigerant flowing through the plurality of third flat tubes 28z exchanges heat with the air, and a part of it dissipates heat or condenses, and reaches the upper region of the internal space of the return header 30. The refrigerant sent to the upper region of the internal space of the return header 30 is sent to the lower region of the return header 30. The refrigerant that has reached the lower region of the return header 30 is divided and flows through a plurality of first flat tubes 28x belonging to the first flow path group X and a plurality of second flat tubes 28y belonging to the second flow path group Y, which are connected to the lower region of the return header 30. The refrigerant flowing through the plurality of first flat tubes 28x and the plurality of second flat tubes 28y exchanges heat with the air again, and further dissipates heat or condenses, and reaches the liquid header 60. The refrigerant flowing through the plurality of first flat tubes 28x belonging to the first flow path group X and the refrigerant flowing through the plurality of second flat tubes 28y belonging to the second flow path group Y merge in the liquid header 60 and then flow through the liquid refrigerant pipe 20.

[0096] (4) Details of the gas header Fig. 7 shows a schematic exploded perspective view of the gas header 50.

[0097] The gas header 50 includes a gas header member 51, an upper portion of a first common member 52, an upper portion of a second common member 53, and an upper portion of a third common member 54. The gas header 50 is configured by brazing the gas header member 51, the upper portion of the first common member 52, the upper portion of the second common member 53, and the upper portion of the third common member 54 to each other.

[0098] Note that the first common member 52, the second common member 53, and the third common member 54 are all members shared also in the liquid header 60 described later, and are members extending in a plate shape from the upper end to the lower end in the inlet / outlet header 40.

[0099] (4-1) Gas header member The gas header member 51 is a member laminated so as to be joined to the right side surface of the first common member 52. The length of the gas header member 51 in the front-rear direction is the same as the length of the first common member 52 and the second common member 53 in the front-rear direction, and is the same as the length of the portion of the flat tube connection plate 54a of the third common member 54 excluding the both side surface portions 54b in the front-rear direction.

[0100] The gas header member 51 is a member made of a metal such as an aluminum alloy.

[0101] The gas header member 51 has a gas header plate-like portion 51a and a semi-circular portion 51b.

[0102] The gas header plate-like portion 51a is a plate-like portion that spreads in the vertical direction and the front-rear direction on the front side and the rear side of the semi-circular portion 51b, respectively.

[0103] The semi-circular portion 51b is provided so as to connect between the front side portion of the gas header plate-like portion 51a and the rear side portion of the gas header plate-like portion 51a, and is a semi-circular arc-shaped portion formed by half of an arc having the longitudinal direction of the gas header 50 as the axial direction. The semi-circular portion 51b bulges toward the side opposite to the first common member 52 side with respect to the gas header plate-like portion 51a. A connection opening 51x connected to the gas refrigerant connection pipe 19a of the first gas refrigerant pipe 19 is provided in the semi-circular portion 51b.

[0104] Note that, in the gas header member 51, each of the front side portion of the gas header plate-like portion 51a and the rear side portion of the gas header plate-like portion 51a contacts the claw portion 54c of the third common member 54 described later, and is caulked from the right side by the claw portion 54c of the third common member 54.

[0105] Note that the partition plate 41 and the upper lid 42 are provided between the gas header member 51 and the first common member 52, and function as a lower lid and an upper lid for forming the internal space of the gas header 50.

[0106] (4-2) First common member The first common member 52 is a member laminated so as to face and contact the right side surface of the second common member 53 and to face and contact the left side surface of the gas header plate-shaped portion 51a of the gas header member 51. The length of the first common member 52 in the front-rear direction is the same as the length of the second common member 53 in the front-rear direction.

[0107] The first common member 52 has a first common plate-shaped portion 52a and a plurality of openings 52x.

[0108] The first common plate-shaped portion 52a has a flat plate shape that extends in the vertical direction and in the front-rear direction.

[0109] The plurality of openings 52x are arranged side by side in the vertical direction and are openings that penetrate in the plate thickness direction of the first common plate-shaped portion 52a.

[0110] The front and rear edges of each opening 52x are located inside the opening 53x of the second common member 53 and inside each flat tube connection opening 54x formed in the flat tube connection plate 54a of the third common member 54 when viewed in the plate thickness direction of the first common member 52. The width of the plurality of openings 52x of the first common member 52 in the front-rear direction is narrower than the width of the flat tube 28 in the front-rear direction. Note that the upper and lower edges of the plurality of openings 52x of the first common member 52 are openings located outside each flat tube connection opening 54x formed in the flat tube connection plate 54a of the third common member 54 when viewed in the plate thickness direction of the first common member 52.

[0111] As a result, both ends in the vicinity of the front and rear of the tip of each flat tube 28 inserted into the gas header 50 can be applied to the edges of the respective openings 52x of the first common member 52, so that the degree of insertion of the flat tube 28 into the gas header 50 can be determined.

[0112] (4-3) Second common member The second common member 53 is a member laminated so as to face and contact the right side surface of the flat tube connection plate 54a of the third common member 54 and to face and contact the left side surface of the first common member 52. The length of the second common member 53 in the front-rear direction is the same as the length of the portion of the flat tube connection plate 54a of the third common member 54 excluding the both side surface portions 54b in the front-rear direction.

[0113] The second common member 53 has a second common plate-like portion 53a and a plurality of openings 53x.

[0114] The second common plate-like portion 53a has a flat plate shape that extends in the vertical direction and in the front-rear direction.

[0115] The plurality of openings 53x are arranged side by side in the vertical direction and are openings that penetrate in the thickness direction of the second common plate-like portion 53a.

[0116] Each opening 53x of the second common member 53 is an opening larger than each flat tube connection opening 54x formed in the flat tube connection plate 54a of the third common member 54. In a state where the second common member 53 is laminated on the flat tube connection plate 54a of the third common member 54, the outer edge of each opening 53x of the second common member 53 is configured to be located outside the outer edge of each flat tube connection opening 54x formed in the flat tube connection plate 54a of the third common member 54 when viewed in the thickness direction of the second common member 53.

[0117] (4-4) Third common member The third common member 54 is a member that mainly constitutes the periphery of the outer shape of the gas header 50 together with the gas header member 51.

[0118] The third common member 54 has a flat tube connection plate 54a, side portions 54b, and claw portions 54c.

[0119] The flat tube connection plate 54a is a flat plate-shaped portion that extends in the vertical direction and in the front-rear direction. A plurality of flat tube connection openings 54x arranged side by side in the vertical direction are formed in the flat tube connection plate 54a. Each flat tube connection opening 54x is an opening that penetrates in the thickness direction of the flat tube connection plate 54a. The flat tube 28 is joined by brazing in a state where one end of the flat tube 28 is inserted into the flat tube connection opening 54x so that the flat tube 28 completely passes through. Each opening 53x of the second common member 53 is larger than the flat tube 28, and when the operation of inserting the flat tube 28 into the flat tube connection opening 54x is performed, no friction occurs between the flat tube 28 and each opening 53x of the second common member 53, so the insertion operation is facilitated.

[0120] The side surface portion 54b extends toward the right on the front side of the flat tube connection plate 54a and has a surface that extends vertically, and extends toward the right on the rear side of the flat tube connection plate 54a and has a surface that extends vertically.

[0121] The claw portion 54c has a portion that extends rearward from the right end portion of the front side surface portion 54b and a portion that extends forward from the right end portion of the rear side surface portion 54b.

[0122] The claw portion 54c is in a state of extending on the extension of the side surface portion 54b in a state before the gas header plate-shaped portion 51a of the second common member 53, the first common member 52, and the gas header member 51 are arranged inside the third common member 54 in a plan view. The claw portion 54c is bent so as to approach each other in a state where the second common member 53, the first common member 52, and the gas header member 51 are arranged inside the third common member 54. As a result, the second common member 53, the first common member 52, and the gas header member 51 are caulked by the third common member 54. And in this state, brazing is performed in the furnace, so that the members are joined by brazing and completely fixed.

[0123] (5) Details of the liquid header FIG. 8 shows a schematic exploded perspective view of the liquid header 60.

[0124] The liquid header 60 includes a first plate-like member 61, a second plate-like member 62, a third plate-like member 63, a fourth plate-like member 64, a fifth plate-like member 65, the lower part of the first common member 52, the lower part of the second common member 53, and the lower part of the third common member 54. The liquid header 60 is formed by brazing the first plate-like member 61, the second plate-like member 62, the third plate-like member 63, the fourth plate-like member 64, the fifth plate-like member 65, the lower part of the first common member 52, the lower part of the second common member 53, and the lower part of the third common member 54 to each other.

[0125] Note that the liquid header 60 is made of a metal such as an aluminum alloy.

[0126] Also, a first connecting pipe 71 (an example of a "first piping part") and a second connecting pipe 72 (an example of a "second piping part") and a liquid refrigerant connection pipe 20a are connected to the liquid header 60.

[0127] In the liquid header 60, the refrigerant flowing in through the liquid refrigerant connection pipe 20a is split into a first refrigerant flow path A and a second refrigerant flow path B after passing through the confluence flow path C. The first refrigerant flow path A is a flow path from the connection part with the confluence flow path C to the first flat tube 28x included in the first flow path group X, and has first flow path portions A1, A2, A3, A4, A5, and A6. The second refrigerant flow path B is a flow path from the connection part with the confluence flow path C to the second flat tube 28y included in the second flow path group Y, and has second flow path portions B1, B2, B3, B4, B5, and B6. In the first refrigerant flow path A, the refrigerant flows in the order of the first flow path portions A1, A2, A3, A4, A5, and A6. In the second refrigerant flow path B, the refrigerant flows in the order of the second flow path portions B1, B2, B3, B4, B5, and B6. The refrigerant that has flowed through the first refrigerant flow path A in the liquid header 60 flows into the first flat tube 28x included in the first flow path group X among the plurality of flat tubes 28. The refrigerant that has flowed through the second refrigerant flow path B in the liquid header 60 flows into the second flat tube 28y included in the second flow path group Y among the plurality of flat tubes 28.

[0128] (5-1) First plate-like member The first plate-shaped member 61 is a plate-shaped member that constitutes the outer wall portion on the right side of the liquid header 60, and the liquid refrigerant connection pipe 20a is connected thereto.

[0129] The first plate-shaped member 61 has a first plate-shaped portion 61a, a pipe connection opening 61x, a first outer wall opening 61b, a second outer wall opening 61c, a third outer wall opening 61d, and a fourth outer wall opening 61e. The first plate-shaped portion 61a is a plate-shaped member that extends in the vertical and longitudinal directions with the left-right direction as the plate thickness direction. The pipe connection opening 61x is an opening that penetrates in the plate thickness direction near the lower end of the first plate-shaped member 61, and the liquid refrigerant connection pipe 20a is connected thereto. The first outer wall opening 61b, the second outer wall opening 61c, the third outer wall opening 61d, and the fourth outer wall opening 61e are openings provided so as to penetrate in the plate thickness direction of the first plate-shaped member 61, respectively.

[0130] The first outer wall opening 61b and the second outer wall opening 61c are connected via a first connecting pipe 71. The first connecting pipe 71 has a first lower pipe portion 71a, a first intermediate pipe portion 71b, and a first upper pipe portion 71c. The first lower pipe portion 71a extends from the first outer wall opening 61b toward the right side, which is a direction away from the first plate-shaped member 61 in the plate thickness direction of the first plate-shaped member 61. The first intermediate pipe portion 71b extends vertically upward from the right end portion of the first lower pipe portion 71a. The first upper pipe portion 71c extends from the upper end portion of the first intermediate pipe portion 71b toward the left side, which is a direction approaching the first plate-shaped member 61 in the plate thickness direction of the first plate-shaped member 61, up to the second outer wall opening 61c.

[0131] The first intermediate piping portion 71b is provided with a temperature sensor 80 that detects the temperature of the refrigerant flowing in the vertical direction through the first intermediate piping portion 71b. In this embodiment, the temperature sensor 80 detects the temperature of the first intermediate piping portion 71b in order to detect the temperature of the refrigerant flowing through the first intermediate piping portion 71b. And in this embodiment, the temperature sensor 80 detects the temperature of the first intermediate piping portion 71b of the first connection pipe 71 at a position away from the liquid refrigerant connection pipe 20a and also away from the second connection pipe 72. Further, in this embodiment, the temperature sensor 80 is provided at a position away from the first plate member 61 and also away from the liquid header 60. Thereby, when the temperature sensor 80 detects the temperature of the first intermediate piping portion 71b of the first connection pipe 71, the influence of the temperature of the refrigerant flowing through the liquid refrigerant connection pipe 20a, the temperature of the refrigerant flowing through the second connection pipe 72, and the temperature of the first plate member 61 is suppressed to a small level, and the detection accuracy can be improved. Also, in the first intermediate piping portion 71b which is a portion extending in the vertical direction, the difference in the distribution state of the refrigerant flowing in the vertical direction inside is suppressed. Thereby, the temperature sensor 80 can improve the detection accuracy. Further, since the temperature sensor 80 is attached to a position away from the liquid header 60 in the first connection pipe 71, the attachment work can be facilitated.

[0132] The third outer wall opening 61d and the fourth outer wall opening 61e are connected via the second connection pipe 72. The second connection pipe 72 has a second lower piping portion 72a, a second intermediate piping portion 72b, and a second upper piping portion 72c. The second lower piping portion 72a extends from the third outer wall opening 61d toward the right side, which is a direction away from the first plate member 61 in the plate thickness direction of the first plate member 61. The second intermediate piping portion 73b extends vertically upward from the right end portion of the second lower piping portion 72a. The second upper piping portion 72c extends from the upper end portion of the second intermediate piping portion 72b to the fourth outer wall opening 61e toward the left side, which is a direction approaching the first plate member 61 in the plate thickness direction of the first plate member 61.

[0133] The flow path lengths of the first communication pipe 71 and the second communication pipe 72 are the same. Also, the flow path length of the first intermediate pipe portion 71b in the first communication pipe 71 and the flow path length of the second intermediate pipe portion 72b in the second communication pipe 72 are the same. Thereby, it is configured such that the pressure loss of the refrigerant passing through the first communication pipe 71 and the pressure loss of the refrigerant passing through the second communication pipe 72 are substantially equal. Thereby, for the refrigerant flowing through the first communication pipe 71 and the second communication pipe 72, for example, it becomes easier to adjust the flow division state, such as adjusting so that approximately the same amount of refrigerant flows. Further, in the present embodiment, it is configured such that the flow path length of the portion of the first refrigerant flow path A excluding the first communication pipe 71 and the flow path length of the portion of the second refrigerant flow path B excluding the second communication pipe 72 are equal. As described above, in the liquid header 60 of the present embodiment, the pressure loss received by the refrigerant flowing through the first refrigerant flow path A and the pressure loss received by the refrigerant flowing through the second refrigerant flow path B can be made equal. Thereby, it becomes possible to evenly distribute the refrigerant to the first flat tube 28x included in the first flow path group X and the second flat tube 28y included in the second flow path group Y.

[0134] Also, the lower end of the first communication pipe 71 is located below the lower end of the second communication pipe 72. Since the first communication pipe 71 belongs to the first refrigerant flow path A located below the second refrigerant flow path B to which the second communication pipe 72 belongs, the flow path configuration in the liquid header 60 can be simplified.

[0135] Note that the first communication pipe 71, the first outer wall opening 61b, and the second outer wall opening 61c constitute the first flow path portion A2 included in the first refrigerant flow path A. Also, the second communication pipe 72, the third outer wall opening 61d, and the fourth outer wall opening 61e constitute the second flow path portion B2 included in the second refrigerant flow path B.

[0136] (5-2) Second plate-like member The second plate-like member 62 is positioned between the first plate-like member 61 and the third plate-like member 63 in the plate thickness direction, and has a second plate-like portion 62a, a branch opening 62b, a first communication opening 62c, and a second communication opening 62d. The second plate-like portion 62a is a plate-like member with the left-right direction as the plate thickness direction and extending in the up-down and front-back directions. The branch opening 62b, the first communication opening 62c, and the second communication opening 62d are all openings penetrating in the plate thickness direction of the second plate-like member 62.

[0137] When viewed from the lamination direction of the first plate-like member 61 and the second plate-like member 62 which is the plate thickness direction of the second plate-like member 62, the branch opening 62b is an opening connecting a portion overlapping with the pipe connection opening 61x of the first plate-like member 61, a portion overlapping with the second outer wall opening 61c of the first plate-like member 61, and a portion overlapping with the third outer wall opening 61d of the first plate-like member 61. After extending upward from the portion overlapping with the pipe connection opening 61x of the first plate-like member 61, the branch opening 62b branches into a flow path extending toward the portion overlapping with the second outer wall opening 61c of the first plate-like member 61 and a flow path extending toward the portion overlapping with the third outer wall opening 61d of the first plate-like member 61 in a narrow portion functioning as a nozzle. Here, among the branch opening 62b, the portion from the portion overlapping with the pipe connection opening 61x of the first plate-like member 61 to the portion functioning as a nozzle is the confluence flow path C. Also, among the branch opening 62b, the portion extending from the portion functioning as a nozzle toward the portion overlapping with the second outer wall opening 61c of the first plate-like member 61 constitutes the first flow path portion A1 included in the first refrigerant flow path A. Further, among the branch opening 62b, the portion extending from the portion functioning as a nozzle toward the portion overlapping with the third outer wall opening 61d of the first plate-like member 61 constitutes the second flow path portion B1 included in the second refrigerant flow path B.

[0138] The first communication opening 62c is an opening extending from the portion overlapping with the first outer wall opening 61b of the first plate-like member 61 toward the portion overlapping with the third lower opening 63l of the third plate-like member 63. The first communication opening 62c constitutes the first flow path portion A3 included in the first refrigerant flow path A.

[0139] The second communication opening 62d is an opening extending from a portion overlapping with the fourth outer wall opening 61e of the first plate-like member 61 toward a portion overlapping with the third upper opening 63h of the third plate-like member 63. The second communication opening 62d constitutes a second flow path portion B3 included in the second refrigerant flow path B.

[0140] (5-3) Third plate-like member The third plate-like member 63 is positioned between the second plate-like member 62 and the fourth plate-like member 64 in the plate thickness direction, and has a third plate-like portion 63a, a third lower opening 63l, and a third upper opening 63h. The third plate-like portion 63a is a plate-like member with the left-right direction as the plate thickness direction and extending in the up-down and front-back directions. Both the third lower opening 63l and the third upper opening 63h are openings penetrating in the plate thickness direction of the third plate-like member 63.

[0141] The third lower opening 63l is an opening overlapping with the introduction region of the lower circulation opening 64l of the fourth plate-like member 64 when viewed from the lamination direction of the third plate-like member 63 and the fourth plate-like member 64, which is the plate thickness direction of the third plate-like member 63.

[0142] The third upper opening 63h is an opening overlapping with the introduction region of the upper circulation opening 64h of the fourth plate-like member 64 when viewed from the lamination direction of the third plate-like member 63 and the fourth plate-like member 64, which is the plate thickness direction of the third plate-like member 63.

[0143] (5-4) Fourth plate-like member The fourth plate-like member 64 is positioned between the third plate-like member 63 and the fifth plate-like member 65 in the plate thickness direction, and has a fourth plate-like portion 64a, a lower circulation opening 64l, and an upper circulation opening 64h. The fourth plate-like portion 64a is a plate-like member with the left-right direction as the plate thickness direction and extending in the up-down and front-back directions. Both the lower circulation opening 64l and the upper circulation opening 64h are openings penetrating in the plate thickness direction of the fourth plate-like member 64.

[0144] The lower circulation opening 64l is an opening configured such that the refrigerant flowing in from the third lower opening 63l of the third plate-like member 63 toward the introduction region on the lower rear side is sent to the ascending region via a nozzle. In this lower circulation opening 64l, the refrigerant that has reached above the ascending region moves to the front side and then is configured to descend in the descending region. Further, the refrigerant that has descended in the descending region is guided to the rear side and thus returned to below the ascending region again. In this way, in the lower circulation opening 64l, the refrigerant flows in a circulating manner. Here, in the ascending region, while the refrigerant flows upward, it is diverted to the diversion opening 65x corresponding to the first flow path portion A5 among the diversion openings 65x formed in the fifth plate-like member 65.

[0145] The upper circulation opening 64h is an opening having the same shape as the lower circulation opening 64l, and is configured such that the refrigerant flowing in from the third upper opening 63h of the third plate-like member 63 into the introduction region on the lower rear side circulates in the upper circulation opening 64h. Here, also in the ascending region of the upper circulation opening 64h, while the refrigerant flows upward, it is diverted to the diversion opening 65x corresponding to the second flow path portion B5 among the diversion openings 65x formed in the fifth plate-like member 65.

[0146] (5-5) Fifth plate-like member The fifth plate-like member 65 is positioned between the fourth plate-like member 64 and the first common member 52 in the plate thickness direction, and has a fifth plate-like portion 65a and a plurality of diversion openings 65x. The fifth plate-like portion 65a is a plate-like member with the left-right direction as the plate thickness direction and extending in the up-down and front-rear directions. The plurality of diversion openings 65x are all openings penetrating in the plate thickness direction of the fifth plate-like member 65.

[0147] The plurality of diversion openings 65x are provided so as to be arranged vertically at a position biased to the rear side in the fifth plate-like member 65. Here, the rear side in the fifth plate-like member 65 corresponds to the upwind side when the outdoor fan 16 is driven. Thereby, since a large amount of refrigerant can be guided to the upwind side of the plurality of flat tubes 28, the heat exchange efficiency can be enhanced.

[0148] The plurality of flow-dividing openings 65x overlap in the plate thickness direction with the opening 52x of the first common member 52 and the opening 53x of the second common member 53. Among the flow-dividing openings 65x formed in the fifth plate-like member 65, the flow-dividing openings 65x corresponding to the first flow path portion A5 communicate in the plate thickness direction with the opening 52x and the opening 53x corresponding to the first flow path portion A6 among the opening 52x of the first common member 52 and the opening 53x of the second common member 53. Among the flow-dividing openings 65x formed in the fifth plate-like member 65, the flow-dividing openings 65x corresponding to the second flow path portion B5 communicate in the plate thickness direction with the opening 52x and the opening 53x corresponding to the second flow path portion B6 among the opening 52x of the first common member 52 and the opening 53x of the second common member 53.

[0149] As described with respect to the gas header 50 above, the opening 52x of the first common member 52, the opening 53x of the second common member 53, and the flat tube connection opening 54x of the third common member 54 communicate with each other in the plate thickness direction. Here, the tip of the flat tube 28 is inserted so as to pass through the flat tube connection opening 54x of the third common member 54, which is wider than the cross-section of the flat tube 28, and the opening 53x of the second common member 53. Further, the insertion of the flat tube 28 is stopped at the opening 52x of the first common member 52, the front-rear width of which is smaller than that of the flat tube 28.

[0150] Note that, similar to the gas header 50, in the liquid header 60 as well, with the second common member 53, the first common member 52, the fifth plate-like member 65, the fourth plate-like member 64, the third plate-like member 63, the second plate-like member 62, and the first plate-like member 61 arranged inside the third common member 54, the claw portion 54c is bent. Thereby, the second common member 53, the first common member 52, the fifth plate-like member 65, the fourth plate-like member 64, the third plate-like member 63, the second plate-like member 62, and the first plate-like member 61 are caulked by the third common member 54. And in this state, brazing is performed in the furnace, so that the mutual members are joined by brazing and completely fixed.

[0151] (6) Features of the Embodiment In the outdoor heat exchanger 11 of the air conditioner 1, when the frost adhering during the heating operation is melted by the defrosting operation, the liquid refrigerant condensed inside the outdoor heat exchanger 11 tends to stay below the outdoor heat exchanger 11. For this reason, it becomes difficult to secure the refrigerant flow rate below the outdoor heat exchanger 11 during the defrosting operation, and the frost adhering to the lower part of the outdoor heat exchanger 11 tends to melt last during the defrosting operation.

[0152] On the other hand, in the outdoor heat exchanger 11 of the present embodiment, in the temperature detection by the temperature sensor 80, temperature detection can be performed only on the refrigerant in the first refrigerant flow path A through which the refrigerant that has passed through the first flat tube 28x belonging to the first flow path group X located at the lowermost position among the plurality of flat tubes 28 of the outdoor heat exchanger 11 flows.

[0153] Thereby, during the defrosting operation, it becomes possible to accurately determine the timing when all the frost adhering to the outdoor heat exchanger 11 has melted based on the detected temperature by the temperature sensor 80. Thereby, for example, it becomes possible to advance the timing of returning from the defrosting operation to the heating operation as compared with the case of performing the defrosting operation for a predetermined time set longer.

[0154] Further, the temperature sensor 80 detects the temperature of the first intermediate pipe portion 71b at a position away from the liquid refrigerant connection pipe 20a, away from the second connection pipe 72, and further away from the first plate-like member 61. Thereby, the temperature sensor 80 can suppress the influence of the temperature of the refrigerant flowing through the liquid refrigerant connection pipe 20a, the temperature of the refrigerant flowing through the second connection pipe 72, and the temperature of the first plate-like member 61, and can improve the detection accuracy.

[0155] Further, the first intermediate pipe portion 71b provided with the temperature sensor 80 extends in the vertical direction, and the refrigerant flows in the vertical direction. For this reason, the detection accuracy can also be improved in that temperature detection can be performed on a portion where the difference in refrigerant temperature is suppressed.

[0156] In addition, in this embodiment, by improving the detection accuracy of the temperature sensor 80, it is possible to avoid a state in which the defrosting operation continues even though the frost adhering to the outdoor heat exchanger 11 has finished melting, and to optimize the return timing of the heating operation.

[0157] Also, in the liquid header 60 of the outdoor heat exchanger 11, the refrigerant flowing in through the liquid refrigerant connection pipe 20a can be split inside the liquid header 60. Therefore, it is not necessary to provide a conventionally known flow divider separately from the liquid header 60. Accordingly, the installation space of the outdoor heat exchanger 11 can be made compact, the component cost can be reduced, and the production process can be simplified by eliminating the need for the connection work of the conventionally known flow divider. Here, examples of the conventionally known flow divider include those that split the refrigerant flowing in from one end of the main body and distribute it to a plurality of capillary tubes connected to the other end side of the main body. In this embodiment, no flow divider for splitting the refrigerant is provided between the liquid refrigerant side of the outdoor heat exchanger 11 and the outdoor expansion valve 12. In particular, in the outdoor heat exchanger 11 of this embodiment, the refrigerant flowing into the liquid header 60 through the liquid refrigerant connection pipe 20a is split by devising the opening shape provided in the second plate-like member 62, which is a single plate-like member constituting the liquid header 60. Therefore, even when splitting inside the liquid header 60, it is possible to keep the thickness of the liquid header 60 in the left-right direction small.

[0158] Furthermore, in the liquid header 60 of this embodiment, not only does it branch from the confluence flow path C into the first refrigerant flow path A and the second refrigerant flow path B, but the refrigerant flowing through the first refrigerant flow path A is further split at the split opening 65x of the fifth plate-like member 65 and then flows into each first flat tube 28x, and the refrigerant flowing through the second refrigerant flow path B is further split at the split opening 65x of the fifth plate-like member 65 and then flows into each second flat tube 28y. Thereby, it is possible to improve the heat exchange efficiency in the outdoor heat exchanger 11.

[0159] (7) Other Embodiments (7-1) Other Embodiment A In the above-described embodiment, the case where the first connection pipe 71 and the second connection pipe 72 are connected in the liquid header 60 and the temperature sensor 80 is provided in the first connection pipe 71 has been described as an example.

[0160] Here, the structure for detecting the temperature of the refrigerant flowing through the first refrigerant flow path A by the temperature sensor 80 is not limited to this. For example, as shown in FIG. 10, instead of providing the first connection pipe 71 as in the above-described embodiment, a configuration may be adopted in which the first plate-shaped member 61 has a first protruding portion 171 protruding in the plate thickness direction. Similarly, for the second connection pipe 72, instead of providing the second connection pipe 72 of the above-described embodiment, a configuration may be adopted in which the first plate-shaped member 61 has a second protruding portion 172 protruding in the plate thickness direction.

[0161] The first protruding portion 171 is formed in the first plate-shaped member 61 so as to bulge toward the right side, which is the outside of the liquid header 60 in the plate thickness direction of the first plate-shaped member 61. Note that on the left side, which is the inside of the first protruding portion 171, a first concave portion 171a recessed toward the right side in the plate thickness direction is formed. Thereby, the end portion on the side opposite to the confluence flow path C side of the portion constituting the first flow path portion A1 of the branch opening 62b in the second plate-shaped member 62 and the first connection opening 62c in the second plate-shaped member 62 are connected via a flow path formed by being sandwiched between the first concave portion 171a, which is the back surface of the first protruding portion 171 of the first plate-shaped member 61, and the second plate-shaped portion 62a of the second plate-shaped member 62. Note that the flow path sandwiched between the first concave portion 171a and the second plate-shaped portion 62a constitutes the first flow path portion A2.

[0162] The second protruding portion 172 is similar to the first protruding portion 171. In the first plate-like member 61, it is formed so as to bulge toward the right side which is the outside of the liquid header 60 in the plate thickness direction of the first plate-like member 61. Note that on the left side which is the inside of the second protruding portion 172, a second concave portion 172a recessed toward the right side in the plate thickness direction is formed. Thereby, the end portion on the side opposite to the confluence channel C side of the portion constituting the second channel portion B1 of the branch opening 62b in the second plate-like member 62 and the second connection opening 62d in the second plate-like member 62 are connected via a channel formed by being sandwiched between the second concave portion 172a which is the back surface of the second protruding portion 172 of the first plate-like member 61 and the second plate-like portion 62a of the second plate-like member 62. Note that the channel sandwiched between the second concave portion 172a and the second plate-like portion 62a constitutes the second channel portion B2.

[0163] Note that both the first protruding portion 171 and the second protruding portion 172 extend in the vertical direction and allow the refrigerant to pass in the vertical direction.

[0164] The temperature sensor 80 is attached to the detected portion 171b of the right side portion which is the outside of the liquid header 60 in the first protruding portion 171. Note that the temperature sensor 80 is preferably provided so as not to contact the first plate-like portion 61a of the first plate-like member 61, and may be attached to the front side or the rear side of the first protruding portion 171.

[0165] The channel lengths of the refrigerant in the first protruding portion 171 and the second protruding portion 172 are equal.

[0166] Also, the lower end of the first protruding portion 171 is located below the lower end of the second protruding portion 172.

[0167] With the above configuration as well, the same effects as those of the above-described embodiment can be achieved.

[0168] (7-2) Other Embodiment B In the above embodiment, the refrigerant that flows into the liquid header 60 via the liquid refrigerant connection pipe 20a and reaches the confluence flow path is divided into two flow paths, i.e., the first refrigerant flow path A and the second refrigerant flow path B. Further, the refrigerant flowing through the first refrigerant flow path A is divided into two or more flow paths within the liquid header 60, and the refrigerant flowing through the second refrigerant flow path B is divided into two or more flow paths within the liquid header 60. The liquid header 60 has been described as an example.

[0169] In contrast, the number of times the refrigerant flowing into the header is divided before reaching the heat transfer pipe such as a flat tube may be only once, or may be three or more times.

[0170] Also, the number of branches when the refrigerant flowing into the header is first divided is not limited to two, and may be three or more.

[0171] (Supplementary Note) As described above, the embodiments of the present disclosure have been described. It will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims.

Explanation of Reference Numerals

[0172] 1 Air conditioner 2 Outdoor unit (outdoor machine) 3 Control unit 11 Outdoor heat exchanger (heat exchanger) 19 First gas refrigerant pipe 19a Gas refrigerant connection pipe 20 Liquid refrigerant pipe 20a Liquid refrigerant connection pipe (refrigerant pipe) 27 Heat exchange section 28 Flat tube (heat transfer pipe) 28x First flat tube (first heat transfer pipe) 28y Second flat tube (second heat transfer pipe) 28z Third flat tube 30 Return header 40 Inlet / outlet header 50 Gas header 51 Gas header member 51a Gas header plate-like portion 52 First common member 53 Second common member 54 Third common member 54c Claw portion 60 Liquid header (header) 61 First plate-like member (outer wall portion) 62 Second plate-like member (plate-like member) 62b Branch opening (opening) 71 First connecting pipe (first piping portion) 71b First intermediate piping portion (portion to be detected) 72 Second connecting pipe (second piping portion) 80 Temperature sensor 171 First protruding portion 171a First recess 171b Portion to be detected 172 Second protruding portion 172a Second recess A First refrigerant flow path B Second refrigerant flow path C Confluence flow path

Prior art documents

Patent documents

[0173]

Patent Document 1

Claims

1. a plurality of heat transfer tubes (28) including a first heat transfer tube (28x) and a second heat transfer tube (28y) disposed above the first heat transfer tube; A header (60) to which a plurality of the heat transfer tubes are connected; A refrigerant pipe (20a) connected to the header; A temperature sensor (80); Equipped with the header has a junction flow path (C) extending from a connection portion of the refrigerant pipe, a first refrigerant flow path (A) connecting the connection portion of the first heat transfer tube and the junction flow path, and a second refrigerant flow path (B) connecting the connection portion of the second heat transfer tube and the junction flow path, The temperature sensor detects a temperature of the refrigerant flowing through the first refrigerant flow path. Heat exchanger (11).

2. A detection position of the temperature sensor is closer to the first refrigerant flow path than the second refrigerant flow path and is closer to the first refrigerant flow path than the refrigerant piping.

2. The heat exchanger of claim 1.

3. The first heat transfer tube includes a portion located at the lowest position among the plurality of heat transfer tubes.

3. A heat exchanger according to claim 1 or 2.

4. The header has an outer wall (61); the outer wall portion is located on an opposite side to a side of the header where a connection portion between the heat transfer tube and the header is located, The first refrigerant flow path has a first piping portion (71), The first piping portion is located on an opposite side of the outer wall portion to a side on which the connection portion between the heat transfer tube and the header is located.

3. A heat exchanger according to claim 1 or 2.

5. The temperature sensor detects the temperature of the refrigerant flowing through the first piping section.

5. The heat exchanger of claim 4.

6. The temperature sensor detects the temperature of the refrigerant flowing through a detection target portion (71b) of the first piping section, The detection portion is a portion through which the refrigerant flows in the vertical direction.

6. The heat exchanger according to claim 5.

7. The second refrigerant flow path has a second piping portion (72), The second piping portion is located on an opposite side of the outer wall portion to a side on which the connection portion between the heat transfer tube and the header is located.

5. The heat exchanger of claim 4.

8. The first piping section and the second piping section have the same length.

8. The heat exchanger of claim 7.

9. A lower end of the first piping section is located lower than a lower end of the second piping section.

8. The heat exchanger of claim 7.

10. The header has an outer wall (61); the outer wall portion is located on an opposite side to a side of the header where a connection portion between the heat transfer tube and the header is located, The outer wall portion includes a first protrusion (171) protruding toward an opposite side to a side where the connection portion between the heat transfer tube and the header is located, the first refrigerant flow path includes a portion through which the refrigerant flows along the first protruding portion on a side of the outer wall portion where the connection portion between the heat transfer tube and the header is located, 3. A heat exchanger according to claim 1 or 2.

11. The temperature sensor detects a temperature of the coolant flowing along the first protrusion.

11. The heat exchanger of claim 10.

12. The temperature sensor detects the temperature of the refrigerant flowing through a detection target portion (171b) of the first protrusion, The detection portion is a portion through which the refrigerant flows in the vertical direction.

12. The heat exchanger of claim 11.

13. The outer wall portion includes a second protruding portion (172) protruding toward the opposite side to the side where the connection portion between the heat transfer tube and the header is located, the second refrigerant flow path includes a portion through which the refrigerant flows along the second protruding portion on a side of the outer wall portion where the connection portion between the heat transfer tube and the header is located.

11. The heat exchanger of claim 10.

14. A flow path length of the first protruding portion of the first refrigerant flow path is equal to a flow path length of the second protruding portion of the second refrigerant flow path.

14. The heat exchanger of claim 13.

15. A lower end of the first protrusion is located lower than a lower end of the second protrusion.

14. The heat exchanger of claim 13.

16. The header has a plate-like member (62) having an opening (62b) penetrating in a plate thickness direction, The opening constitutes a part of the junction flow path, a part of the first refrigerant flow path, and a part of the second refrigerant flow path.

3. A heat exchanger according to claim 1 or 2.

17. A heat exchanger according to claim 1 or 2; A control unit (3) capable of switching between an operation in which the heat exchanger functions as an evaporator of the refrigerant and a defrosting operation in which the heat exchanger is defrosted; Equipped with The control unit performs the defrosting operation based on the temperature detected by the temperature sensor. Air conditioning equipment.

18. The control unit terminates the defrosting operation based on the temperature detected by the temperature sensor.

18. An air conditioning apparatus as claimed in claim 17.

19. The heat exchanger is provided in an outdoor unit (2).

18. An air conditioning apparatus as claimed in claim 17.

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