Heat exchanger and refrigeration cycle device provided with heat exchanger

Abstract

Provided are: a heat exchanger capable of suppressing frosting of flat perforated pipes on the lowermost layer; and a refrigeration cycle device provided with the heat exchanger. The first heat exchanger (11) is provided with a plurality of flat perforated pipes (110) arranged side by side in the vertical direction, and a flow divider (170) serving as a pressure loss part. The plurality of flat perforated tubes includes flat perforated tubes of a first tube group (114) and flat perforated tubes of a second tube group (116) other than the flat perforated tubes of the first tube group. The first tube group forms a first passage (P1). The first passage is a flow path for a refrigerant including a flat perforated tube (110L) disposed in the lowermost layer of the first heat exchanger. The second tube group forms a second passage (P2) as a flow path for the refrigerant. When the first heat exchanger functions as an evaporator, at least a part of the refrigerant supplied to the first heat exchanger flows through the first passage, then flows into the pressure loss part, flows out of the pressure loss part, and flows into the second passage.

Description

Technical Field

[0001] This disclosure relates to a heat exchanger using a flat porous tube and a refrigeration cycle apparatus having a heat exchanger. Background Technology

[0002] When using a heat exchanger with flat porous tubes as an evaporator to exchange heat between cold air and refrigerant, frost formation on the bottom layer of the flat porous tubes in the heat exchanger can easily become a problem.

[0003] In order to suppress frost formation on the bottommost flat porous tube of a heat exchanger, in Patent Document 1 (Japanese Patent Application Publication No. 2019-60596), the refrigerant passage containing the bottommost flat porous tube is made longer than the passage length of other refrigerant passages to suppress frost formation on the bottommost flat porous tube. Summary of the Invention

[0004] The problem that the invention aims to solve However, in the heat exchanger of Patent Document 1 (Japanese Patent Application Publication No. 2019-60596), it is sometimes impossible to sufficiently suppress frost formation on the bottommost flat porous tube. From the viewpoint of suppressing frost formation on the bottommost flat porous tube, there is room for improvement.

[0005] Methods for solving problems The heat exchanger of the first viewpoint includes multiple flat porous tubes and a pressure loss section for refrigerant flow. The multiple flat porous tubes are arranged vertically. The multiple flat porous tubes include: a first group of flat porous tubes, which includes the flat porous tubes arranged at the bottom layer of the heat exchanger; and a second group of flat porous tubes other than the first group. The flat porous tubes of the first group form a first passage as a flow path for the refrigerant. The second group forms a second passage as a flow path for the refrigerant. When the heat exchanger functions as an evaporator, at least a portion of the refrigerant supplied to the heat exchanger flows into the pressure loss section after passing through the first passage, and flows out of the pressure loss section into the second passage.

[0006] In the heat exchanger of the first viewpoint, a pressure loss section is provided downstream of the first passage in the direction of refrigerant flow when the refrigerant is used as an evaporator. Therefore, in the heat exchanger of the first viewpoint, it is possible to ensure a large pressure difference from when the refrigerant enters the first passage to when it enters the second passage, or in other words, a large temperature difference from when the refrigerant enters the first passage to when it enters the second passage. Therefore, in the heat exchanger of the first viewpoint, it is possible to ensure the heat released from the first passage when the heat exchanger functions as an evaporator and to suppress frost formation in the first passage.

[0007] In the heat exchanger of the second viewpoint, when the heat exchanger functions as an evaporator, all the refrigerant supplied to the heat exchanger flows into the pressure loss section after passing through the first passage, and then flows into the second passage after passing through the pressure loss section.

[0008] In the heat exchanger of the second viewpoint, when the heat exchanger functions as an evaporator, all the refrigerant flowing into the heat exchanger flows through the first passage. Therefore, it is possible to obtain a larger amount of heat released from the first passage when the heat exchanger functions as an evaporator.

[0009] In a heat exchanger based on a first or second viewpoint, the first tube assembly comprises multiple flat, porous tubes arranged in parallel.

[0010] In the heat exchanger of the third perspective, excessive pressure loss in the first passage can be suppressed.

[0011] In the heat exchanger of the fourth viewpoint, in the heat exchanger of the first viewpoint or the second viewpoint, the flow path area of ​​each flat porous tube in the first tube group is greater than the flow path area of ​​each flat porous tube in the second tube group.

[0012] In the heat exchanger of the fourth perspective, excessive pressure loss in the first passage can be suppressed.

[0013] In the heat exchanger of the fifth viewpoint, in any of the first to fourth viewpoints, the number of flat porous tubes contained in the first tube group is less than the number of flat porous tubes contained in the second tube group.

[0014] In the heat exchanger of the fifth viewpoint, the refrigerant flow rate flowing in each flat porous tube of the first passage can be increased, and the heat released from each flat porous tube of the first passage when the heat exchanger functions as an evaporator can be obtained more significantly.

[0015] In the heat exchanger described in any of the first to fifth viewpoints, the pressure loss section is a throttling section of the refrigerant flow path disposed between the first passage and the second passage.

[0016] In the heat exchanger of the sixth viewpoint, by providing a throttling section at the downstream end of the first passage, a large pressure difference can be ensured from the point of entry into the first passage to the point of entry into the second passage; in other words, a large temperature difference can be ensured from the point of entry into the first passage to the point of entry into the second passage. Therefore, in the heat exchanger of the sixth viewpoint, a larger amount of heat released from the first passage when the heat exchanger functions as an evaporator can be obtained, and frost formation in the first passage can be suppressed.

[0017] In the heat exchanger described in any of the first to fifth viewpoints, the pressure loss section is a distributor of the refrigerant flow path disposed between the first passage and the second passage.

[0018] In the heat exchanger of the seventh viewpoint, a distributor using a flat, porous tube that diverts the refrigerant to the second tube assembly after it passes through the first passage ensures a large pressure difference from the point of entry into the first passage to the point of entry into the second passage—in other words, a large temperature difference from the point of entry into the first passage to the point of entry into the second passage. Therefore, in the heat exchanger of the first viewpoint, a larger amount of heat released from the first passage when the heat exchanger functions as an evaporator can be obtained, and frost formation on the first passage can be suppressed.

[0019] The heat exchanger of the eighth viewpoint, in any of the heat exchangers of the first to fifth viewpoints, further includes a manifold disposed in the refrigerant flow path between the first and second passages. The pressure loss section is a nozzle disposed inside the manifold.

[0020] In the heat exchanger of the eighth perspective, by using nozzles arranged in the manifold, a large pressure difference can be ensured from the point of entry into the first passage to the point of entry into the second passage; in other words, a large temperature difference can be ensured from the point of entry into the first passage to the point of entry into the second passage. Therefore, in the heat exchanger of the first perspective, a larger amount of heat released from the first passage when the heat exchanger functions as an evaporator can be obtained, and frost formation in the first passage can be suppressed.

[0021] The heat exchanger of the ninth viewpoint, in the heat exchanger of the first viewpoint, also has a bypass path that guides the refrigerant to the second path in a manner that does not flow through the first path.

[0022] In the heat exchanger of the ninth viewpoint, when a large amount of refrigerant is supplied to the heat exchanger, it is possible to suppress the adverse situation where the pressure loss becomes too large due to the refrigerant flowing entirely in the first passage, and the efficiency of the refrigeration cycle device using the heat exchanger decreases.

[0023] In the heat exchanger of the tenth viewpoint, in any of the first to ninth viewpoints, multiple rows of flat porous tubes are arranged in the direction of the airflow generated by the blower supplying air to the heat exchanger. The first passage is arranged only on the upwind side in the direction of the airflow.

[0024] In the heat exchanger of the tenth perspective, frost formation is easily suppressed at the flat, porous tube on the upper and lower part of the heat exchanger where frost or ice adhesion is prone to problems.

[0025] The refrigeration cycle device of the eleventh concept includes a refrigerant circuit and a blower. The refrigerant circuit includes a heat exchanger from any of the first to tenth concepts, which serves as a heat source and heat exchanger, and a compressor for compressing the refrigerant. The blower supplies air to the heat exchanger.

[0026] In the refrigeration cycle device of the eleventh viewpoint, frost formation on the flat porous tubes of the first tube group of the heat exchanger can be suppressed, thus shortening the interruption time of operation that allows the heat exchanger to function as an evaporator. Attached Figure Description

[0027] Figure 1 This is a schematic structural diagram of an air conditioning device according to one embodiment of the refrigeration cycle apparatus disclosed herein.

[0028] Figure 2 It is used for explanation Figure 1 A schematic top view of the configuration of the first heat exchanger in the heat source unit of the air conditioning unit.

[0029] Figure 3 yes Figure 2 A schematic perspective view of the heat exchanger of the first embodiment of this disclosure used in an air conditioning unit.

[0030] Figure 4 yes Figure 3 A magnified three-dimensional view of a portion of the first heat exchanger.

[0031] Figure 5 It is a schematic representation Figure 3 The diagram shows the construction of the first heat exchanger and the flow of refrigerant in the first heat exchanger when it functions as an evaporator.

[0032] Figure 6 It is a schematic representation Figure 3 The diagram shows the flow of refrigerant in the first passage of the first heat exchanger when the first heat exchanger functions as an evaporator.

[0033] Figure 7 This is a diagram schematically illustrating the construction of a first heat exchanger in another example, and schematically illustrating the flow of refrigerant in the first heat exchanger when it functions as an evaporator.

[0034] Figure 8A This diagram illustrates the difference between the refrigerant flow in the heat exchanger of this disclosure and the refrigerant flow in a conventional heat exchanger, and is a conceptual representation of the refrigerant flow in the heat exchanger of this disclosure.

[0035] Figure 8BThis is a diagram used to illustrate the difference between the flow of refrigerant in the heat exchanger of this disclosure and the flow of refrigerant in a conventional heat exchanger, and is a conceptual representation of the flow of refrigerant in a conventional heat exchanger.

[0036] Figure 9 This is a Morrill diagram that schematically illustrates an air conditioning unit operating in heating mode according to one embodiment of the refrigeration cycle apparatus of this disclosure.

[0037] Figure 10 This is a diagram that conceptually represents the flow of refrigerant in the first passage of the heat exchange section of the first heat exchanger in Modification A.

[0038] Figure 11 It is a schematic cross-sectional view obtained by cutting the first heat exchanger of deformed example C using an imaginary plane orthogonal to the direction of extension of the flat porous tube.

[0039] Figure 12 This is a diagram depicting the internal structure of a portion of the first manifold of the first heat exchanger in variant D.

[0040] Figure 13 This is a diagram that conceptually represents the flow of refrigerant in the heat exchanger of variant E. Detailed Implementation

[0041] Embodiments of the heat exchanger and the refrigeration cycle apparatus having the heat exchanger of this disclosure will be described with reference to the accompanying drawings.

[0042] (1) Overall structure Reference Figure 1 An overview of the refrigeration cycle apparatus of this disclosure will be provided. Figure 1 This is a schematic structural diagram of an air conditioning device 1 according to one embodiment of the refrigeration cycle apparatus of this disclosure.

[0043] Air conditioning unit 1 is a device capable of cooling and heating a space to be conditioned through a vapor compression refrigeration cycle. Furthermore, the type of refrigeration cycle device disclosed herein is not limited to air conditioning units; for example, it could also be a hot water supply device.

[0044] like Figure 1 As shown, the air conditioning unit 1 mainly includes a heat source unit 2, utilization units 3a and 3b, a liquid refrigerant connecting pipe 4 and a gaseous refrigerant connecting pipe 5, and a control unit 23. The control unit 23 controls the operation of the constituent equipment of the heat source unit 2 and the utilization units 3a and 3b.

[0045] Liquid refrigerant connecting pipe 4 and gaseous refrigerant connecting pipe 5 connect the heat source unit 2 to the utilization units 3a and 3b. In the air conditioning unit 1, the heat source unit 2 and the utilization units 3a and 3b are connected via refrigerant connecting pipes 4 and 5, thereby forming a refrigerant circuit 6 (see reference). Figure 1 In refrigerant circuit 6, such as... Figure 1 As shown, the compressor 8, flow direction switching mechanism 10, first heat exchanger 11, first expansion mechanism 12, first shut-off valve 13, second shut-off valve 14, second expansion mechanisms 31a, 31b and second heat exchangers 32a, 32a are connected by refrigerant piping.

[0046] In refrigerant circuit 6, R32, an HFC refrigerant, is sealed as a refrigerant. However, the type of refrigerant is not limited to R32; other refrigerants may include R410A, R1234yf, R1234ze(E), R290, CO2, etc.

[0047] In addition, Figure 1 In this example, the air conditioning unit 1 has one heat source unit 2 and two utilization units 3a and 3b, but the number of units is only for illustration. The air conditioning unit 1 may have multiple heat source units, or it may have one or more utilization units.

[0048] (2) Detailed structure The following describes the heat source unit 2, the utilization units 3a and 3b, the liquid refrigerant connection pipe 4, the gaseous refrigerant connection pipe 5, and the control unit 23 of the air conditioning unit 1.

[0049] (2-1) Heat source unit The heat source unit 2 may be installed outdoors, such as on the roof of a building equipped with an air conditioning unit 1, or around the exterior walls of the building, but is not limited to these locations.

[0050] In this embodiment, the heat source unit 2 is housed in a casing 2a (see reference 2a) containing various devices for housing the heat source unit 2. Figure 2 A side-blowing type unit that takes in air for heat exchange with the refrigerant from the side (rear and left side) of the housing 2a and blows out the air after heat exchange with the refrigerant from the side (front) of the housing 2a (see reference). Figure 2 However, the type of heat source unit 2 is not limited to the side-blowing type. It can also be an up-blowing type unit that draws in air from the side of the housing 2a to exchange heat with the refrigerant and blows the air after heat exchange with the refrigerant upward from the top of the housing 2a.

[0051] The heat source unit 2 mainly includes a liquid receiver 7, a compressor 8, a flow direction switching mechanism 10, a first heat exchanger 11, a first expansion mechanism 12, a first shut-off valve 13, a second shut-off valve 14, and a first fan 15 (see reference). Figure 1 ).

[0052] Furthermore, the heat source unit 2 includes an intake pipe 17, an exhaust pipe 18, a first gaseous refrigerant pipe 19, a liquid refrigerant pipe 20, and a second gaseous refrigerant pipe 21 (see reference). Figure 1 The suction pipe 17 connects the flow direction switching mechanism 10 and the suction side of the compressor 8. A liquid receiver 7 is provided in the suction pipe 17. The discharge pipe 18 connects the discharge side of the compressor 8 to the flow direction switching mechanism 10. The first gaseous refrigerant pipe 19 connects the flow direction switching mechanism 10 to the gas end of the first heat exchanger 11. The liquid refrigerant pipe 20 connects the liquid end of the first heat exchanger 11 to the first shut-off valve 13. The first expansion mechanism 12 is provided in the liquid refrigerant pipe 20. The second gaseous refrigerant pipe 21 connects the flow direction switching mechanism 10 to the second shut-off valve 14.

[0053] (2-1-1) Compressor The compressor 8 is a device that draws in low-pressure refrigerant flowing into the refrigeration cycle from the suction pipe 17, compresses it to increase its pressure to the high pressure of the refrigeration cycle, and discharges the high-pressure refrigerant into the discharge pipe 18. The motor of the compressor 8 (not shown) is controlled by a frequency converter. The speed of the motor of the compressor 8 is adjusted by the control unit 23 according to the operating conditions. Alternatively, the compressor 8 may also be a compressor with a constant motor speed.

[0054] (2-1-2) Flow direction switching mechanism The flow direction switching mechanism 10 is a mechanism that switches the flow direction of refrigerant in the refrigerant circuit 6 according to the received operating mode instruction or the time of defrosting during heating operation. In this embodiment, the flow direction switching mechanism 10 is a four-way switching valve.

[0055] During cooling operation (including dehumidification operation) and defrosting operation, the flow direction switching mechanism 10 connects the suction pipe 17 to the second gaseous refrigerant pipe 21 and the discharge pipe 18 to the first gaseous refrigerant pipe 19 (this connection state of the piping based on the flow direction switching mechanism 10 is referred to as the first state), thereby switching the flow direction of the refrigerant in the refrigerant circuit 6 in a manner that delivers the refrigerant discharged from the compressor 8 to the first heat exchanger 11 (see reference). Figure 1 (The solid line in the middle).

[0056] During heating operation, the flow direction switching mechanism 10 connects the suction pipe 17 to the first gaseous refrigerant pipe 19 and the discharge pipe 18 to the second gaseous refrigerant pipe 21 (this connection state of the piping based on the flow direction switching mechanism 10 is referred to as the second state), thereby switching the flow direction of the refrigerant in the refrigerant circuit 6 in a manner that delivers the refrigerant discharged from the compressor 8 to the second heat exchangers 32a and 32b (see reference). Figure 1 (The dashed line in the middle).

[0057] In addition, the flow direction switching mechanism 10 is not limited to a four-way switching valve, but can also be configured to combine multiple solenoid valves and refrigerant pipes to achieve the switching of the refrigerant flow direction as described above.

[0058] (2-1-3) First heat exchanger The first heat exchanger 11 functions as a heat exchanger (condenser) during refrigeration / defrosting operation and as an evaporator (heat absorber) during heating operation. The first heat exchanger 11 is an example of the heat exchanger in the claims.

[0059] The structure of the first heat exchanger 11 and the flow of refrigerant in the first heat exchanger 11 will be explained later.

[0060] (2-1-4) First expansion mechanism The first expansion mechanism 12 is a mechanism in the refrigerant circuit 6 that expands the refrigerant flowing between the second heat exchangers 32a, 32b of the utilization units 3a, 3b and the first heat exchanger 11. The first expansion mechanism 12 is, for example, an electronic expansion valve whose opening degree can be adjusted. The opening degree of the first expansion mechanism 12 is adjusted by the control unit 23 according to the operating conditions.

[0061] (2-1-5) First fan The first fan 15 generates airflow to supply air to the first heat exchanger 11. The first fan 15 generates an airflow that flows from the outside of the housing 2a into the heat source unit 2, passes through the first heat exchanger 11, and flows out of the housing 2a. The first fan 15 is, for example, a propeller fan. However, the type of the first fan 15 is not limited to a propeller fan, and it can also be other types of fans.

[0062] (2-2) Utilizing Unit Units 3a and 3b are used to set up in the air-conditioned object space or around the air-conditioned object space (e.g., the space behind the ceiling of the air-conditioned object space).

[0063] Unit 3a mainly includes a second expansion mechanism 31a, a second heat exchanger 32a, and a second fan 33a (see reference). Figure 1 The unit 3b mainly comprises a second expansion mechanism 31b, a second heat exchanger 32b, and a second fan 33b (see reference). Figure 1 ).

[0064] (2-2-1) Second expansion mechanism The second expansion mechanisms 31a and 31b are mechanisms in the refrigerant circuit 6 that expand the refrigerant flowing between the second heat exchangers 32a and 32b of the utilization units 3a and 3b and the first heat exchanger 11. The second expansion mechanisms 31a and 31b are, for example, electronic expansion valves with adjustable opening degrees. The opening degree of the second expansion mechanisms 31a and 31b is adjusted by the control unit 23 according to the operating conditions.

[0065] (2-2-2) Second heat exchanger The second heat exchangers 32a and 32b function as heat absorbers (evaporators) to cool indoor air during cooling operation and as heat exothermic devices (condensers) to heat indoor air during heating operation.

[0066] The liquid side of the second heat exchangers 32a and 32b is connected to the liquid refrigerant connecting pipe 4 via refrigerant piping, and the gas side of the second heat exchangers 32a and 32b is connected to the gas refrigerant connecting pipe 5 via refrigerant piping. The second heat exchangers 32a and 32b are, for example, cross-finned finned tube heat exchangers with multiple heat transfer tubes (not shown) and multiple fins (not shown).

[0067] (2-2-3) Second fan The second fans 33a and 33b generate an airflow that flows from the outside (air-conditioned space) of the housing (not shown) that houses the various devices of the utilization units 3a and 3b, into the utilization units 3a and 3b, and then flows out of the housing (air-conditioned space) through the second heat exchangers 32a and 32b. The second fans 33a and 33b are, for example, centrifugal fans.

[0068] (2-3) Refrigerant connecting pipe Refrigerant connecting pipes 4 and 5 are refrigerant piping installed on-site during the installation of air conditioning unit 1. One end of liquid refrigerant connecting pipe 4 is connected to the first shut-off valve 13 of heat source unit 2, and the other end of liquid refrigerant connecting pipe 4 is connected to the refrigerant piping, which is connected to the liquid side of the second heat exchangers 32a and 32b of utilization units 3a and 3b (see reference). Figure 1 One end of the gas refrigerant connecting pipe 5 is connected to the second shut-off valve 14 of the heat source unit 2, and the other end of the gas refrigerant connecting pipe 5 is connected to the refrigerant piping, which is connected to the gas side of the second heat exchangers 32a and 32b of the utilization units 3a and 3b (see reference). Figure 1 ).

[0069] (2-4) Control Department The control unit 23 is configured to communicate with a control board (not shown) containing a CPU, ROM, and RAM, which is installed in the heat source unit 2 and the utilization units 3a and 3b. Furthermore, in Figure 1 For convenience, the control unit 23 is shown in the diagram in a position separate from the heat source unit 2 and the utilization units 3a and 3b.

[0070] like Figure 1As shown by the dashed line, the control unit 23 is electrically connected to the components of the air conditioning unit 1. Specifically, the control unit 23 is electrically connected to, for example, the compressor 8, the flow direction switching mechanism 10, the first expansion mechanism 12, the first fan 15, the second expansion mechanisms 31a and 31b, and the second fans 33a and 33b. Furthermore, the control unit 23 is also electrically connected to various sensors (not shown) installed in the heat source unit 2 and the utilization units 3a and 3b.

[0071] The control unit 23 controls the equipment constituting the air conditioning unit 1 by executing a program for controlling the air conditioning unit 1 (the CPU executes a program stored in the ROM), based on operations from a remote control (not shown) and measurement values ​​from various sensors (not shown).

[0072] The control unit 23 controls the components of the air conditioning unit 1 to enable the air conditioning unit 1 to perform cooling operation (including dehumidification operation) and heating operation. Furthermore, when predetermined conditions are met during the heating operation of the air conditioning unit 1, the control unit 23 switches the operation of the air conditioning unit 1 to defrost operation. The operation of the air conditioning unit 1 during each operation is shown below.

[0073] (3) Operation of the air conditioning unit The cooling operation (including dehumidification operation), heating operation, and defrosting operation of the air conditioning unit 1 will be described. The defrosting operation is an operation performed when the heating operation is temporarily interrupted during the heating operation to melt the frost and ice attached to the first heat exchanger 11.

[0074] During refrigeration operation, the refrigerant circulates in the refrigerant circuit 6 in the following order: compressor 8, first heat exchanger 11, first expansion mechanism 12, second expansion mechanisms 31a and 31b, second heat exchangers 32a and 32b, and liquid receiver 7.

[0075] During heating operation, the refrigerant circulates in the refrigerant circuit 6 in the following order: compressor 8, second heat exchangers 32a and 32b, second expansion mechanism 31a and 31b, first expansion mechanism 12, first heat exchanger 11, and liquid receiver 7.

[0076] During defrosting operation, similar to cooling operation, the refrigerant circulates in the refrigerant circuit 6 in the following order: compressor 8, first heat exchanger 11, first expansion mechanism 12, second expansion mechanisms 31a, 31b, second heat exchangers 32a, 32b, and receiver 7. In other words, in the air conditioning device 1 of this embodiment, by causing the refrigerant to flow in the refrigerant circuit 6 in the opposite direction to that during heating operation, the frost and ice adhering to the first heat exchanger 11 are melted.

[0077] The operation of the air conditioning unit 1 during refrigeration is explained.

[0078] During refrigeration operation, the flow direction switching mechanism 10 switches the connection state of the piping to the first state described above. Then, the low-pressure (hereinafter referred to as low-pressure) gaseous refrigerant drawn into the refrigeration cycle of the compressor 8 from the suction pipe 17 is compressed in the compressor 8 to become high-pressure (hereinafter referred to as high-pressure) in the refrigeration cycle, and then discharged to the discharge pipe 18. The high-pressure gaseous refrigerant discharged to the discharge pipe 18 is conveyed to the first heat exchanger 11 via the flow direction switching mechanism 10. The high-pressure gaseous refrigerant conveyed to the first heat exchanger 11 exchanges heat with the air supplied by the first fan 15 in the first heat exchanger 11, which functions as a refrigerant heat exchanger, and releases heat, becoming a high-pressure liquid refrigerant. The high-pressure liquid refrigerant, after releasing heat in the first heat exchanger 11, is conveyed to the second expansion mechanisms 31a and 31b via the first expansion mechanism 12, the first shut-off valve 13, and the liquid refrigerant connecting pipe 4. The refrigerant supplied to the second expansion mechanisms 31a and 31b is depressurized to a low pressure by the second expansion mechanisms 31a and 31b, becoming a low-pressure gas-liquid two-phase refrigerant. This low-pressure gas-liquid two-phase refrigerant, depressurized by the second expansion mechanisms 31a and 31b, is then supplied to the second heat exchangers 32a and 32b. The low-pressure gas-liquid two-phase refrigerant supplied to the second heat exchangers 32a and 32b undergoes heat exchange with the air supplied by the second fans 33a and 33b, causing it to evaporate. The air cooled in the second heat exchangers 32a and 32b is blown into the air-conditioned space. The low-pressure gaseous refrigerant, after evaporation in the second heat exchangers 32a and 32b, is drawn back into the compressor 8 through the gaseous refrigerant connecting pipe 5, the second shut-off valve 14, the flow switching mechanism 10, and the liquid receiver 7.

[0079] During refrigeration operation, the control unit 23 performs control as follows, for example. However, the control method of the control unit 23 described herein is an example and is not limited to this.

[0080] Based on measurements from sensors (not shown), the control unit 23 controls the opening of electronic expansion valves, which are examples of the second expansion mechanisms 31a and 31b, in a manner that ensures the superheat of the refrigerant at the outlet of each of the second heat exchangers 32a and 32b reaches the target superheat. Furthermore, the control unit 23 controls the operating capacity of the compressor 8 in a manner that brings the evaporation temperature close to the target evaporation temperature.

[0081] The operation of the air conditioning unit 1 during heating operation is explained.

[0082] During heating operation, the flow direction switching mechanism 10 switches the piping connection to the second state described above. Then, the low-pressure gaseous refrigerant drawn into the compressor 8 from the suction pipe 17 is compressed to high pressure in the compressor 8 and discharged through the discharge pipe 18. The high-pressure gaseous refrigerant discharged to the discharge pipe 18 is transported to the second heat exchangers 32a and 32b via the flow direction switching mechanism 10, the second shut-off valve 14, and the gaseous refrigerant connecting pipe 5. The high-pressure gaseous refrigerant transported to the second heat exchangers 32a and 32b exchanges heat with the air supplied by the second fans 33a and 33b in the second heat exchangers 32a and 32b, releasing heat and becoming a high-pressure liquid refrigerant or a gas-liquid two-phase refrigerant. The air heated by heat exchange with the refrigerant in the second heat exchangers 32a and 32b is blown into the air-conditioned space. The high-pressure refrigerant, after releasing heat in the second heat exchangers 32a and 32b, is transported to the first expansion mechanism 12 via the second expansion mechanisms 31a and 31b, the liquid refrigerant connecting pipe 4, and the first shut-off valve 13. The refrigerant transported to the first expansion mechanism 12 is depressurized, becoming a low-pressure gas-liquid two-phase refrigerant. This low-pressure gas-liquid two-phase refrigerant, depressurized by the first expansion mechanism 12, is transported to the first heat exchanger 11. The low-pressure gas-liquid two-phase refrigerant, functioning as an evaporator, exchanges heat with air supplied by the first fan 15 in the first heat exchanger 11, evaporating into a low-pressure gaseous refrigerant. The low-pressure refrigerant, after evaporation in the first heat exchanger 11, is drawn back into the compressor 8 via the flow switching mechanism 10 and the liquid receiver 7.

[0083] During heating operation, the control unit 23 performs control as follows, for example. However, the control method of the control unit 23 described herein is an example and is not limited to this.

[0084] Based on measurements from a sensor (not shown), the control unit 23 controls the opening of an electronic expansion valve, which is an example of the first expansion mechanism 12, in a manner that ensures the superheat of the refrigerant at the outlet of the first heat exchanger 11 reaches a target superheat. Furthermore, the control unit 23 controls the operating capacity of the compressor 8 in a manner that brings the evaporation temperature close to the target evaporation temperature.

[0085] Furthermore, when the conditions for starting defrosting operation are met during heating operation, the control unit 23 switches the operation of the air conditioning unit 1 from heating operation to defrosting operation. The conditions for starting defrosting operation are, for example, a condition where the temperature of the refrigerant flowing in the first heat exchanger 11 is lower than a specified temperature, or a condition where the continuous heating operation time exceeds a specified time, but are not limited to these conditions.

[0086] The defrosting operation is the same as the cooling operation, in which the flow switching mechanism 10 switches the connection state of the piping to the first state described above, allowing the first heat exchanger 11 to function as a refrigerant heat exchanger. Explanation of how the refrigerant flows in the air conditioning unit 1 during defrosting operation is omitted.

[0087] The control unit 23 performs defrosting operation until the defrosting operation end condition is met (until a predetermined defrosting time has elapsed, or until the defrosting of the first heat exchanger 11 is determined to be complete based on the measurement values ​​of various sensors installed on the air conditioning unit 1). Specifically, for example, when the measurement value of the temperature sensor (not shown) installed on the first gas refrigerant pipe 19 is higher than a predetermined temperature for a predetermined time, the control unit 23 determines that the defrosting of the first heat exchanger 11 is complete. When the defrosting operation end condition is met, the control unit 23 ends the defrosting operation and restarts the heating operation of the air conditioning unit 1.

[0088] (4) First heat exchanger Further reference Figures 2-6 The shape and structure of the first heat exchanger 11 are described.

[0089] Figure 2 This is a schematic top view of the heat source unit 2, used to illustrate the configuration of the first heat exchanger 11 in the heat source unit 2. Figure 3 This is a schematic three-dimensional view of the first heat exchanger 11. Figure 4 This is a partially enlarged three-dimensional view of the first heat exchanger 11. Figure 5 It is a diagram showing the structure of the first heat exchanger 11 and schematically showing the flow of refrigerant in the first heat exchanger 11 when the first heat exchanger 11 functions as an evaporator. Figure 6 This is a diagram schematically showing the flow of refrigerant in the first passage P1 of the first heat exchanger 11 when the first heat exchanger 11 functions as an evaporator. Figure 6 It is a diagram depicting the end face of the flat porous tube 110 of the first tube group 114 of the first heat exchanger 11, which is described later, on the side of the first manifold 150.

[0090] in addition, Figure 5 This is a schematic diagram depicting the construction of the first heat exchanger 11. Therefore, for example, the first heat exchanger 11 is as follows: Figure 3 The figure shown has an L-shape, but... Figure 5 The shape is depicted as a straight line (I-shape). Furthermore, for example, the number of flat porous tubes 110 (indicated by dashed lines) recorded in the first heat exchanger 11 does not depict the actual number of flat porous tubes 110 present in the first heat exchanger 11.

[0091] In the following description, terms such as "left," "right," "front," "back," "in front," and "back" are sometimes used to indicate direction and position. Unless otherwise specified, the directions indicated by these terms follow the direction of the arrows shown in the attached diagram.

[0092] As described above, the heat source unit 2 has a housing 2a, inside which are housed a liquid reservoir 7, a compressor 8, a flow direction switching mechanism 10, a first heat exchanger 11, a first expansion mechanism 12, a first shut-off valve 13, a second shut-off valve 14, and a first fan 15. The interior of the housing 2a is divided into a mechanical chamber R1, mainly housing the compressor 8, liquid reservoir 7, flow direction switching mechanism 10, first expansion mechanism 12, first shut-off valve 13, and second shut-off valve 14, and a blower chamber R2, mainly housing the first heat exchanger 11 and the first fan 15 (see reference). Figure 2 Additionally, in Figure 2 The description of the equipment located in the machine room R1 is omitted.

[0093] In this embodiment, such as Figure 2 and Figure 3 As shown, the first heat exchanger 11 has a roughly L-shaped design. Figure 2 As shown, when viewed from above, the first heat exchanger 11 extends from the rear right side of the housing 2a (near the machine room R1) along the back of the housing 2a to near the rear left end of the housing 2a, and then changes direction near the rear left end of the housing 2a to near the front left end.

[0094] A first fan 15 is disposed in front of the first heat exchanger 11. When the first fan 15 is operating, air is drawn in from the back and left side of the housing 2a and passes through the first heat exchanger 11 (see reference). Figure 2 (The arrow in the image). The air after passing through the first heat exchanger 11 is finally blown forward from the front surface of the casing 2a (see reference). Figure 2 (The arrow in the image).

[0095] like Figure 3 and Figure 5 As shown, the first heat exchanger 11 mainly includes a heat exchange section 100, a first manifold 150, a second manifold 160, a distributor 170, a first piping 180, and a second piping 190.

[0096] The heat exchange section 100, first manifold 150, second manifold 160, distributor 170, first piping 180, and second piping 190 of the first heat exchanger 11 are made of aluminum or aluminum alloy, but are not limited thereto. The heat exchange section 100, first manifold 150, second manifold 160, distributor 170, first piping 180, and second piping 190 are connected to each other by brazing or the like.

[0097] (4-1) Structure of the first heat exchanger The various structures of the first heat exchanger 11 will be described.

[0098] (4-1-1) Heat exchange section The heat exchange section 100 is the main part of the first heat exchanger 11. Heat exchange between the refrigerant and air is primarily carried out by the heat exchange section 100. The heat exchange section 100 has a plurality of flat porous tubes 110 arranged in a vertical direction and a plurality of fins 120 mounted on the flat porous tubes 110. In this embodiment, seventy-three flat porous tubes 110 are arranged in the heat exchange section 100 in a vertical direction. However, the number of flat porous tubes 110 in the heat exchange section 100 is merely an example and can be varied appropriately.

[0099] In this embodiment, such as Figure 4 As shown, in the first heat exchanger 11, two rows of heat exchange sections 100 are arranged in the direction of the airflow generated by the first fan 15 (airflow direction A). In other words, in the first heat exchanger 11 of this embodiment, multiple rows of flat porous tubes 110 are arranged in the airflow direction A.

[0100] Hereinafter, the heat exchange section 100 located on the upstream side of the two heat exchange sections 100 will sometimes be referred to as heat exchange section 100u, and the heat exchange section 100 located on the downstream side will be referred to as heat exchange section 100d (see reference). Figure 4 However, when explaining the common features of heat exchange sections 100u and 100d, etc., without the need to specifically distinguish between the two, they are sometimes simply referred to as heat exchange section 100.

[0101] Furthermore, the airflow direction A here refers to the direction of airflow through the heat exchange section 100 when viewed from above along the vertical direction of the flat porous tubes 110 arranged in the heat exchange section 100. In other words, the airflow direction A here refers to the direction of airflow through the heat exchange section 100 when viewed from above (viewed from above).

[0102] Furthermore, in the first heat exchanger 11 of this embodiment, two rows of heat exchange sections 100 are arranged in the airflow direction A, but the first heat exchanger 11 may also have only one row of heat exchange sections 100. Additionally, the first heat exchanger 11 may have three or more rows of heat exchange sections 100 in the airflow direction A.

[0103] like Figure 6 As shown, the flat porous tube 110 is a flat heat transfer tube (in the cross-section of the heat transfer tube, the thickness (height in the vertical direction) is thinner than the width). Figure 4 and Figure 6As shown, each flat porous tube 110 has a plurality of holes 112 extending parallel to each other along the extension direction of the flat porous tube 110. The holes 112 of each flat porous tube 110 function as flow paths for the refrigerant.

[0104] Each flat porous tube 110 of each heat exchange section 100 has a generally L-shaped form corresponding to the shape of the first heat exchanger 11. One end of each flat porous tube 110 is connected to the first manifold 150, and the other end of each flat porous tube 110 is connected to the second manifold 160. Specifically, in top view, each flat porous tube 110 extends from the first manifold 150, which is located on the rear right side of the housing 2a near the machine compartment R1, along the back of the housing 2a to near the rear left end, and then changes direction near the rear left end of the housing 2a to extend to the second manifold 160, which is located near the front left end of the housing 2a.

[0105] Furthermore, the shape of the flat porous tube 110 (in other words, the shape of the first heat exchanger 11) is not limited to an L-shape. Depending on the type of heat source unit 2, the required performance, etc., the shape of the flat porous tube 110 may also be a straight shape (I-shape), a U-shape, a quadrilateral shape, or other shapes other than an L-shape.

[0106] Each heat exchange section 100 has two groups of flat porous tubes 110 (first group 114 and second group 116). In other words, the plurality of flat porous tubes 110 includes the flat porous tubes 110 of the first group 114 and the flat porous tubes 110 of the second group 116. The flat porous tubes 110 of the second group 116 of the heat exchange section 100 mainly facilitate the heat exchange between the refrigerant and the air.

[0107] The first tube group 114 includes one or more flat porous tubes 110. The flat porous tubes 110 of the first tube group 114 include those disposed at the lowest level of the first heat exchanger 11 (disposed at the lowest level of each heat exchange section 100). Here, the designation "110L" indicates the flat porous tube 110 disposed at the lowest level of the first heat exchanger 11 (see reference). Figure 5 and Figure 6 ).

[0108] In this embodiment, the first tube assembly 114 includes a flat porous tube 110L disposed at the bottom layer of each of the heat exchange sections 100u and 100d, and a flat porous tube 110 disposed at the second layer from the bottom. However, depending on the design, the first tube assembly 114 may only include the flat porous tube 110L disposed at the bottom layer of each of the heat exchange sections 100u and 100d, or it may include not only the flat porous tubes 110 disposed at the bottom layer and the second layer from the bottom of each of the heat exchange sections 100u and 100d, but also the flat porous tubes 110 disposed at the third layer and above from the bottom.

[0109] The second tube group 116 comprises flat porous tubes 110 other than those in the first tube group 114. Specifically, in this embodiment, all flat porous tubes 110 in the second tube group 116, excluding those in the first tube group 114, belong to the second tube group 116. Furthermore, it is preferable that the number of flat porous tubes 110 in the first tube group 114 is less than the number of flat porous tubes 110 in the second tube group 116. For example, in this embodiment, the first tube group 114 comprises four flat porous tubes 110 (two tubes x two columns), and the second tube group 116 comprises one hundred and forty-two flat porous tubes 110 (seventy-one tubes x two columns). Preferably, the number of flat porous tubes 110 in the first tube group 114 is less than 10% of the total number of flat porous tubes 110 in the first heat exchanger 11, more preferably less than 5%.

[0110] The flat porous tube 110 of the first tube group 114 forms the first passage P1, which serves as the flow path for the refrigerant.

[0111] The flat porous tube 110 of the second tube group 116 forms a second passage P2 as a flow path for the refrigerant.

[0112] When the first heat exchanger 11 functions as both a heat exchanger and an evaporator, it supplies refrigerant flow as follows.

[0113] When the first heat exchanger 11 functions as an evaporator, the refrigerant flows through the first passage P1 and then into the distributor 170, which serves as a pressure loss section, and then into the second passage P2 after passing through the distributor 170. Specifically, in this embodiment, when the first heat exchanger 11 functions as an evaporator, all the refrigerant supplied to the first heat exchanger 11 flows through the first passage P1 and then into the distributor 170, and then into the second passage P2 after passing through the distributor 170. Details regarding the flow of the refrigerant within the first heat exchanger 11 when it functions as an evaporator will be described later.

[0114] When the first heat exchanger 11 functions as a heat exchanger, the refrigerant flows in the first heat exchanger 11 in the opposite direction to when the first heat exchanger 11 functions as an evaporator. In summary, when the first heat exchanger 11 functions as a heat exchanger, the refrigerant flows into the distributor 170 after passing through the second passage P2, and then flows into the first passage P1 after passing through the distributor 170. Specifically, in this embodiment, when the first heat exchanger 11 functions as a heat exchanger, all the refrigerant supplied to the first heat exchanger 11 flows into the distributor 170 after passing through the second passage P2, and then flows into the first passage P1 after passing through the distributor 170. Details regarding the flow of the refrigerant in the first heat exchanger 11 when it functions as a heat exchanger will be described later.

[0115] The fins 120 divide adjacent flat porous tubes 110 in the vertical direction (the direction in which the flat porous tubes 110 are arranged) into multiple ventilation paths for airflow. Multiple horizontally elongated notches 122 are formed in the fins 120 to accommodate the insertion of multiple flat porous tubes 110 (see reference). Figure 4 The extension direction of the notch 122 is approximately the same as the airflow direction A generated by the first fan 15. The notch 122 opens to the windward side so that the flat porous tube 110 can be inserted from the windward side to the upwind side in the ventilation direction. The notches 122 of the fin 120 are formed at predetermined intervals in the vertical direction.

[0116] (4-1-2) First manifold The first manifold 150 is a longitudinally elongated, hollow cylindrical component that is closed at both the upper and lower ends. One first manifold 150 is provided for each of the two rows of heat exchange sections 100. However, the first manifold 150 can also be a single cylindrical component shared by the two rows of heat exchange sections 100, with its interior divided into spaces corresponding to the two rows of heat exchange sections 100 respectively.

[0117] Two first manifolds 150 are positioned upright near the machine room R1 on the rear right side of the housing 2a (see reference). Figure 2 Each of the multiple flat porous tubes 110 corresponding to the heat exchange section 100 is connected to one end of each first manifold 150.

[0118] Furthermore, in the first heat exchanger 11 of this embodiment, the interior of each first manifold 150 is divided into four independent spaces 152a to 152d in the vertical direction. The spaces 152a, 152b, 152c, and 152d are arranged sequentially from the bottom inside the first manifold 150, but the internal structure is not limited to this.

[0119] like Figure 5As shown, one end of the first conduit 180 is connected to and communicates with the first conduit 180 in the lowest space 152a. Figure 5 As shown, a liquid refrigerant pipe 20 is connected to the other end of the first piping 180 (the end opposite to the side connected to space 152a of the first manifold 150). Furthermore, as... Figure 5 As shown, in the space 152a of each first manifold 150, one end of the lowest layer of the flat porous tube 110L of the heat exchange section 100 corresponding to the first manifold 150 is connected, and the space 152a is connected to the lowest layer of the flat porous tube 110L of the heat exchange section 100.

[0120] like Figure 5 As shown, space 152b is connected to the piping (main pipe) 174 of the splitter 170, and is connected to the main body 172 of the splitter 170 via piping 174. Furthermore, at one end of the space 152b of each first manifold 150, there is a flat porous pipe 110 (flat porous pipe 110 of the first pipe group 114) of the heat exchange section 100 corresponding to that first manifold 150, which is the second layer from the bottom, and space 152b is connected to the flat porous pipe 110 of the heat exchange section 100, which is the second layer from the bottom.

[0121] like Figure 5 As shown, space 152c is connected to the piping (capillary tube) 176 of the distributor 170, and is also connected to the main body 172 of the distributor 170 via piping 176. Furthermore, in each first manifold 150, space 152c is connected, for example, to one end of the flat porous tube 110 from the third to the fourteenth layer from the bottom of the heat exchange section 100 corresponding to that first manifold 150, and space 152c is connected to the flat porous tube 110 from the third to the fourteenth layer from the bottom of the heat exchange section 100.

[0122] like Figure 5 As shown, one end of the second conduit 190 is connected to and communicates with the uppermost space 152d. Figure 5 As shown, a first gas refrigerant pipe 19 is connected to the other end of the second pipe 190 (the end opposite to the side connected to the space 152d of the first manifold 150). Furthermore, for example, one end of a flat porous pipe 110 from the fifteenth to the seventy-third layer from the bottom of the heat exchange section 100 corresponding to that first manifold 150 is connected to the space 152d of each first manifold 150, and the space 152d communicates with the flat porous pipe 110 from the fifteenth to the seventy-third layer from the bottom of the heat exchange section 100.

[0123] (4-1-3) Second manifold The second manifold 160 is a longitudinally elongated, hollow cylindrical component that is closed at both the upper and lower ends. One second manifold 160 is provided for each of the two rows of heat exchange sections 100. However, the second manifold 160 can also be a single cylindrical component shared by the two rows of heat exchange sections 100, with its interior divided into spaces corresponding to the two rows of heat exchange sections 100 respectively.

[0124] Two second manifolds 160 are installed in an upright position at the front left end of the housing 2a of the heat source unit 2 (see reference). Figure 2 Each of the multiple flat porous tubes 110 connected to the corresponding heat exchange section 100 in each of the second manifolds 160 has one end (the end not connected to the first manifold 150).

[0125] In the first heat exchanger 11 of this embodiment, the interior of each second manifold 160 is divided into eight independent spaces 162a to 162h. Inside the first manifold 150, spaces 162a, 162b, 162c, 162d, 162e, 162f, 162g, and 162h are arranged sequentially from bottom to top, but the internal structure is not limited to this.

[0126] Space 162a is connected to one end of the lowest layer and the second layer from the bottom of the heat exchange section 100 corresponding to the first manifold 150, and space 162a is in communication with the flat porous tube 110 of the first pipe group 114.

[0127] Space 162b is connected to spaces 162c to 162h via multiple pipes 164, and space 162b is fully connected to all spaces 162c to 162h. Furthermore, at one end of space 162b connected to the flat porous pipe 110 of the heat exchange section 100 corresponding to the first manifold 150, which is located from the third to the fourteenth layer from the bottom, space 162b is connected to the flat porous pipe 110 of the heat exchange section 100 from the third to the fourteenth layer from the bottom.

[0128] The same applies to spaces 162c to 162h, therefore the description is simplified.

[0129] Space 162c is connected to space 162b via piping 164, and is connected to one end of a flat porous pipe 110 from the fifteenth to the twenty-fourth layer of the heat exchange section 100 corresponding to the first manifold 150.

[0130] Space 162d is connected to space 162b via piping 164, and is connected to one end of a flat porous pipe 110 from the twenty-fifth to the thirty-fourth layer of the heat exchange section 100 corresponding to the first manifold 150.

[0131] Space 162e is connected to space 162b via piping 164, and is connected to one end of a flat porous pipe 110 from the 35th to the 44th layer from the bottom of the heat exchange section 100 corresponding to the first manifold 150.

[0132] Space 162f is connected to space 162b via piping 164, and is connected to one end of a flat porous pipe 110 from the forty-fifth to the fifty-fourth layer from the bottom of the heat exchange section 100 corresponding to the first manifold 150.

[0133] Space 162f is connected to space 162b via piping 164, and is connected to one end of a flat porous pipe 110 from the 55th to the 64th layer from the bottom of the heat exchange section 100 corresponding to the first manifold 150.

[0134] Space 162h is connected to space 162b via piping 164, and is connected to one end of a flat porous pipe 110 from the sixty-fifth to the seventy-third layer from the bottom of the heat exchange section 100 corresponding to the first manifold 150.

[0135] (4-1-4) Diverter The distributor 170 is a device that, when the first heat exchanger 11 functions as an evaporator, diverts the refrigerant flowing in from the first passage P1 to the respective spaces 152c of the two first manifolds 150.

[0136] The distributor 170 has a distributor body 172, a main pipe 174, and multiple capillary pipes 176. The main pipe 174 connects the distributor body 172 to the space 152b of each of the two first manifolds 150. The capillary pipes 176 connect the distributor body 172 to the space 152c of each of the two first manifolds 150.

[0137] The distributor body 172 is a mechanism that distributes the refrigerant flowing in from the pipe 174 to multiple pipes 176. Additionally, the distributor 170 here distributes the refrigerant flowing into the distributor body 172 to two pipes 176, but the number of flow paths that the distributor 170 distributes the refrigerant to can be appropriately determined based on the path design of the first heat exchanger 11, etc.

[0138] Here, the shunt 170 is an example of the pressure loss section of this disclosure.

[0139] When the first heat exchanger 11 is used as an evaporator, if a predetermined amount of refrigerant (e.g., a predetermined maximum flow rate under normal operation) flows in the order of the distributor 170, which functions as a pressure loss section, and the second passage P2, the total pressure loss in the pressure loss section is greater than the total pressure loss of the second passage P2. In other words, the pressure loss section here is defined as the portion that is greater than the total pressure loss of the second passage P2 when the first heat exchanger 11 is used as an evaporator and a predetermined amount of refrigerant (e.g., a predetermined maximum flow rate under normal operation) flows through it.

[0140] Preferably, the minimum cross-sectional area of ​​the flow path of the pressure loss section in the splitter 170 or other manner is formed to be smaller than the sum of the flow path cross-sectional areas of the lowest-level flat porous tube 110 included in the first passage P1. Additionally, for example, as in Modification A described later, if there are other flat porous tubes 110 connected in parallel with the lowest-level flat porous tube 110 in the first passage P1, the minimum cross-sectional area of ​​the flow path of the pressure loss section is formed to be smaller than the sum of the flow path cross-sectional areas of the lowest-level flat porous tube 110 included in the first passage P1 and the flat porous tubes 110 connected in parallel with that lowest-level flat porous tube 110.

[0141] With this configuration, it is easy to compensate for insufficient pressure reduction when the flow occurs solely through the first passage P1 by utilizing the pressure loss section.

[0142] To illustrate with a specific example, in this embodiment, the first passage P1 includes two rows of flat porous tubes 110 of heat exchange sections 100 connected in parallel. Therefore, the sum of the flow path cross-sectional areas of the lowest layer of flat porous tubes 110 included in the first passage P1 refers to the sum of the flow path cross-sectional areas of the holes 112 of the two flat porous tubes 110. Furthermore, it is preferable that the minimum cross-sectional area of ​​the flow path of the splitter 170 or other pressure loss section is formed to be smaller than the sum of the flow path cross-sectional areas of the holes 112 of the two flat porous tubes 110.

[0143] In addition, as a means to increase the pressure loss of the distributor 170, it is considered to make the pressure loss in the distributor 170 reach a desired level by providing a throttling section 173 in the refrigerant flow path within the distributor body 172.

[0144] Furthermore, as another means of increasing pressure loss in the distributor 170, it is considered to provide a throttling section 173 in the distributor body 172, or instead of providing a throttling section 173 in the distributor body 172, and appropriately select the pipe diameters of the piping 174 and piping 176 relative to the specified amount of refrigerant flowing into the first heat exchanger 11.

[0145] Furthermore, as another means of increasing pressure loss in the splitter 170, it is also possible to consider, based on or instead of any of the above means, providing a throttling section 174a in the piping 174, or providing a throttling section 176a in the piping 176.

[0146] In addition, Figure 5 The diagram shows all of the throttling parts 173, 174a, and 176a, but this does not mean that all of the throttling parts 173, 174a, and 176a need to be installed.

[0147] Furthermore, while this example illustrates the function of the diverter 170 as a pressure loss section, other parts besides the pressure loss section can also function as pressure loss sections. For instance, if diversion is not required after the flow passes through the first passage P1, it can also be used as described above. Figure 7 In this way, the splitter 170 is omitted, and a throttling section 171a is provided on the piping 171 that connects the space 152b and space 152c of the first manifold 150.

[0148] (5) Flow of refrigerant in the first heat exchanger (5-1) Features and effects of the heat exchanger disclosed herein First, refer to Figure 8~ Figure 9 The features of the heat exchanger disclosed herein and the effects obtained by the heat exchanger disclosed herein shall be described.

[0149] Figure 8A This diagram illustrates the difference between the refrigerant flow in the heat exchanger of this disclosure and the refrigerant flow in a conventional heat exchanger. It is a conceptual representation of the refrigerant flow in the heat exchanger HEX of this disclosure when it functions as an evaporator.

[0150] Figure 8B This diagram illustrates the difference between the refrigerant flow in the heat exchanger of this disclosure and the refrigerant flow in a conventional heat exchanger. It is a conceptual representation of the refrigerant flow in the conventional heat exchanger HEX1 when it functions as an evaporator.

[0151] Additionally, this is used for explanation. Figure 8A The heat exchanger HEX depicted is a simplified version of the heat exchanger disclosed herein, designed to facilitate understanding, and differs in construction from the first heat exchanger 11 described above. For example, in... Figure 8A The heat exchanger HEX is not depicted in a manner where the refrigerant flows in a zigzag pattern within the flat porous tube 110 in the first passage P1. Furthermore, for example, in... Figure 8AThe heat exchanger HEX is not depicted in a manner in which the refrigerant flows back and forth in the flat porous tube 110 in the second passage P2.

[0152] Furthermore, for Figure 8B The heat exchanger HEX1 is omitted in detail, but it is the same as the heat exchanger HEX disclosed herein, except that the refrigerant flow pattern and the fact that the distributor DIV is not intended to impart pressure loss. The heat exchanger HEX1, like the heat exchanger HEX, is a heat exchanger with multiple flat porous tubes 110 arranged in the vertical direction.

[0153] Figure 9 This is a Morrill diagram schematically illustrating the heating operation of an air conditioning unit having a refrigeration cycle device with a heat exchanger HEX, used to explain the effects obtained through the heat exchanger HEX of this disclosure. Additionally, Figure 9 The diagram is for illustrative purposes and does not represent an actual Morrill diagram of the air conditioning unit disclosed herein.

[0154] exist Figure 8B In the conventional heat exchanger HEX1 shown, when the heat exchanger HEX1 is used as an evaporator, all the refrigerant flows into the distributor DIV, and after being diverted by the distributor DIV into the various passages of the heat exchange section of the heat exchanger HEX1, it flows out of the heat exchanger HEX1. The heat exchanger HEX1 is constructed such that the passage containing the lowest layer of flat heat transfer tubes (called the lowest layer passage) has a longer passage length than the other passages. For example, in Figure 8B In the example, in the passage outside the bottom layer of the heat exchange section, the refrigerant flows out without backflow (the passage length is the length of one flat, porous tube). Conversely, in the bottom layer of the heat exchange section, the refrigerant flows out after backflowing twice and passing through the length of three flat tubes. Figure 8B In the heat exchanger HEX1, the pressure loss of the lowest passage of the heat exchange section is greater than that of the other passages. Therefore, the amount of refrigerant flowing through the lowest passage of the heat exchange section is small, and almost no heat exchange occurs. As a result, the flat heat transfer tubes at the bottom of the heat exchange section are not prone to frost formation.

[0155] However, in the conventional heat exchanger HEX1, the pressure loss in the lowest passage of the heat exchange section is not as large as that in the heat exchanger HEX of this disclosure, and the refrigerant hardly flows through the lowest passage of the heat exchange section. Therefore, when the external gas temperature drops, the flat porous tube in the lowest passage of the heat exchange section is also prone to frost formation.

[0156] Furthermore, in heat exchanger HEX1, the pressure loss in the lowest passage of the heat exchange section is greater than in other passages. Therefore, during defrosting operation, when heat exchanger HEX1 is used as a condenser, the amount of refrigerant flowing in the lowest passage of the heat exchange section tends to decrease. Consequently, if frost or ice temporarily adheres to the lowest passage in heat exchanger HEX1, the removal of frost or ice (until defrosting operation is complete) takes time.

[0157] In contrast, Figure 8A In the heat exchanger HEX of this disclosure, when the heat exchanger HEX is used as an evaporator, the refrigerant flows through the first passage P1 of the heat exchange section (a passage including the lowest layer of flat porous tube 110L) into the distributor 170, which serves as a pressure loss section, and then flows into the second passage P2 formed by the flat porous tubes 110 (of the second tube group 116), excluding the first tube group 114 that forms the first passage P1. In particular, in the first heat exchanger 11 described in the first embodiment, when the first heat exchanger 11 is used as an evaporator, all the refrigerant flowing into the first heat exchanger 11 flows through the first passage P1 of the heat exchange section into the distributor 170, which serves as a pressure loss section, and then flows into the second passage P2 of the heat exchange section formed by the flat porous tubes 110 of the second tube group 116.

[0158] In the heat exchanger HEX of this disclosure, a large pressure loss can be obtained through the distributor 170, which is an example of a pressure loss section. Therefore, when the air conditioning unit of one embodiment of the refrigeration cycle apparatus of this disclosure is operated in heating mode, the Morrill diagram is as follows. Figure 9 As shown, a larger temperature difference (Ta-Tb) between the inlet and outlet of the first passage P1 can be obtained. Furthermore, when all the refrigerant flowing into the heat exchanger HEX flows through the first passage P1, as in the first heat exchanger 11 of the first embodiment, a larger amount of refrigerant can flow through the first passage P1 compared to the lowest passage of the conventional heat exchanger HEX1. As a result, heat release proportional to the product of the flowing refrigerant quantity and the temperature difference (Ta-Tb) can be obtained in the first passage P1 of the heat exchanger HEX, and frost formation is easily suppressed even when the temperature of the air undergoing heat exchange is low in the first passage P1 of the heat exchanger HEX.

[0159] Furthermore, in the heat exchanger HEX, during defrosting operation, when the heat exchanger HEX is used as a condenser, all the refrigerant flowing into the heat exchanger HEX flows into the first passage P1 after passing through the second passage P2 and the distributor 170. Therefore, in the heat exchanger HEX, even if frost adheres to the first passage P1, or ice adheres to the flat porous tube 110L of the first passage P1, the time required to remove them (defrosting operation time) can be shortened.

[0160] It should be noted that when heat exchangers HEX and HEX1 function as heat exchangers, the refrigerant flow direction is the opposite to that when they function as evaporators; therefore, detailed explanations are omitted here.

[0161] (5-2) Flow of refrigerant in the first heat exchanger Next, refer to Figure 5 as well as Figure 6 The flow of refrigerant in the first heat exchanger 11 when it functions as an evaporator as described in the above embodiment will be explained. It should be noted that, regarding the flow of refrigerant when the first heat exchanger 11 functions as a heat exchanger, only the flow direction of the refrigerant is opposite to that when it functions as an evaporator, therefore, a detailed explanation is omitted here.

[0162] When the first heat exchanger 11 functions as an evaporator, refrigerant flows from the liquid refrigerant pipe 20 into the first piping 180, and then the refrigerant flows into the space 152a between the two first manifolds 150. For example... Figure 5 and Figure 6 As shown, the refrigerant flowing into space 152a flows in the flat porous tube 110L (first passage P1) of the heat exchange section 100 communicating with space 152, turns back in space 162a of the second manifold 160 communicating with the flat porous tube 110L, and flows in the second-lowest layer of the flat porous tube 110 (first passage P1) of the heat exchange section 100 communicating with space 162a to space 152b of the first manifold 150 communicating with the flat porous tube 110. The refrigerant flowing into space 152b passes through the splitter 170 in the order of piping 174, splitter body 172, and piping 176, and is split into the space 152c of the two first manifolds 150. The refrigerant flowing into the space 152c of each first manifold 150 flows through the flat porous pipe 110 (second passage P2) of the heat exchange section 100 communicating with the space 152c to the space 162b of the second manifold 160. The refrigerant flowing into the space 162b of each second manifold 160 flows separately to multiple piping 164 and flows into the spaces 162c to 162h of the second manifold 160, and then flows through the flat porous pipe 110 (second passage P2) communicating with the spaces 162c to 162h of the second manifold 160 to the space 152d of the first manifold 150. The refrigerant flowing into the space 152d of the two first manifolds 150 flows into the first gaseous refrigerant pipe 19 through the second piping 190.

[0163] Furthermore, in this embodiment, the first tube assembly 114 has two heat exchange sections 100, each comprising a plurality of flat porous tubes 110 arranged in parallel (connected in parallel). By including such a plurality of flat porous tubes 110 arranged in parallel, even when all the refrigerant flowing into the first heat exchanger 11 flows through the first passage P1, excessive pressure loss in the flat porous tubes 110 of the first passage P1 can be suppressed. In other words, when all the refrigerant supplied to the first heat exchanger 11 is to flow through a single flat porous tube 110, the pressure loss may become excessive. In contrast, in the first heat exchanger 11 of this embodiment, since it includes a plurality of flat porous tubes 110 arranged in parallel (connected in parallel), the generation of such excessive pressure loss can be suppressed.

[0164] In this embodiment, the refrigerant flows through the flat porous tube 110L in the first passage P1 and then through the second layer of flat porous tubes 110 from the bottom; however, this structure is only one example. For instance, the first passage P1 may also consist solely of the flat porous tubes 110L, and the refrigerant flowing through the two rows of heat exchange sections 100 through the flat porous tubes 110L may immediately flow into the distributor 170. However, if such a structure is adopted, it may be necessary to connect the first piping 180 to the second manifold 160 side of the first heat exchanger 11. However, from the viewpoint of ease of manufacturing the first heat exchanger 11, it is preferable that the first piping 180 and the second piping 190 are connected to the same manifold (in particular, the first manifold 150 in this embodiment).

[0165] (6) Characteristics (6-1) The first heat exchanger 11 has multiple flat porous tubes 110 and a pressure loss section for refrigerant flow.

[0166] Pressure loss components can be, for example, a flow divider 170. Pressure loss components can be, for example, throttling sections 173, 174a, and 176a provided within the flow divider 170. Furthermore, the pressure loss component can also be a throttling section 171a provided in the piping 171.

[0167] Multiple flat porous tubes 110 are arranged vertically. The multiple flat porous tubes 110 include: flat porous tubes 110 of a first tube group 114, which includes the lowest flat porous tube 110 (110L) disposed in the first heat exchanger 11; and flat porous tubes 110 of a second tube group 116 other than the flat porous tubes 110 of the first tube group 114. The flat porous tubes 110 of the first tube group 114 form a first passage P1 as a refrigerant flow path. The flat porous tubes 110 of the second tube group 116 form a second passage P2 as a refrigerant flow path. When the first heat exchanger 11 functions as an evaporator, at least a portion of the refrigerant supplied to the first heat exchanger 11 flows into a pressure loss section after passing through the first passage P1, and flows out from the pressure loss section into the second passage P2.

[0168] In the first heat exchanger 11, a pressure loss section is provided downstream of the first passage P1 in the direction of refrigerant flow when used as an evaporator. Therefore, in the first heat exchanger 11, a large pressure difference can be ensured from the point of entry into the first passage P1 to the point of entry into the second passage P2; in other words, a large temperature difference can be ensured from the point of entry into the first passage P1 to the point of entry into the second passage P2. Thus, in the first heat exchanger 11, the heat released from the first passage P1 when the first heat exchanger 11 functions as an evaporator can be ensured, and frost formation on the first passage P1 can be suppressed.

[0169] (6-2) In the first heat exchanger 11, when the first heat exchanger 11 functions as an evaporator, all the refrigerant supplied to the first heat exchanger 11 flows into the pressure loss section after passing through the first passage P1, and then flows into the second passage P2 after passing through the pressure loss section.

[0170] In the second viewpoint, when the first heat exchanger 11 functions as an evaporator, all the refrigerant flowing into the first heat exchanger 11 passes through the first passage P1. Therefore, a larger amount of heat released from the first passage P1 can be obtained when the first heat exchanger 11 functions as an evaporator. Consequently, the lowest layer of the flat porous tube 110 (110L) in the first heat exchanger 11 is less prone to frost formation.

[0171] Furthermore, in the first heat exchanger 11, when the first heat exchanger 11 functions as a heat exchanger, all the refrigerant flowing in flows into the first passage P1 after passing through the second passage P2. By allowing all the refrigerant to flow through the first passage P1, during reverse-cycle defrosting when the first heat exchanger 11 is used as a heat exchanger, the frost or ice adhering to the flat porous tubes 110 of the first tube group 114 can be melted and removed in a relatively short time.

[0172] For example, even if the water generated during defrosting freezes around the flat porous tube 110L at the bottom of the first heat exchanger 11, the ice attached to the flat porous tube 110L can be melted and removed in a relatively short time by reverse circulation defrosting operation.

[0173] (6-3) In the first heat exchanger 11, the first tube group 114 includes a plurality of flat porous tubes 110 arranged in parallel.

[0174] Specifically, in the above embodiment, when the first heat exchanger 11 functions as an evaporator, in the first passage P1, the refrigerant flows parallel through the lowest layer of the two heat exchange sections 100, then flows parallel through the second layer of the two heat exchange sections 100 from the bottom. Furthermore, in the above embodiment, when the first heat exchanger 11 functions as a heat exchanger, in the first passage P1, the refrigerant flows parallel through the second layer of the two heat exchange sections 100 from the bottom, then flows parallel through the lowest layer of the two heat exchange sections 100, then flows parallel through the bottom layer of the two heat exchange sections 100, then flows parallel through the bottom layer of the two heat exchange sections 100, then flows parallel through the bottom layer of the two heat exchange sections 100, then flows parallel through the bottom layer of the two heat exchange sections 100.

[0175] In the first heat exchanger 11, the generation of excessive pressure loss in the first passage P1 can be suppressed.

[0176] (6-4) In the first heat exchanger 11, the first tube group 114 contains fewer flat porous tubes 110 than the second tube group 116 contains.

[0177] In the first heat exchanger 11, the refrigerant flow rate of each flat porous tube 110 of the first passage P1 can be increased, and the heat released from each flat porous tube 110 of the first passage P1 can be obtained more when the first heat exchanger 11 functions as an evaporator / heat releaser.

[0178] (6-5) The air conditioning unit 1 includes a refrigerant circuit 6 and a first fan 15, which serves as an example of a blower. The refrigerant circuit 6 includes a first heat exchanger 11, which serves as a heat source heat exchanger, and a compressor 8, which compresses the refrigerant. The first fan 15 supplies air to the first heat exchanger 11.

[0179] In the air conditioning unit 1, frost formation on the flat porous tube 110 of the first tube group 114 of the first heat exchanger 11 can be suppressed, thus shortening the interruption time of operation of the first heat exchanger 11 as an evaporator.

[0180] Furthermore, in the air conditioning unit 1, as described above, the defrosting of the flat porous tube 110 of the first tube group 114 of the first heat exchanger 11 can be completed in a short time. Therefore, the defrosting operation that interrupts the operation of the first heat exchanger 11 as an evaporator can be completed in a short time.

[0181] (7) Variations The above embodiments can be appropriately modified as shown in the following variations. Furthermore, each variation can also be appropriately combined with other variations within a non-contradictory scope.

[0182] (7-1) Variation A In the above embodiment, in the first passage P1, after the refrigerant flows through the lowest layer of the two heat exchange sections 100 arranged side by side, the refrigerant flows through the second layer of the two heat exchange sections 100 arranged side by side from the bottom.

[0183] However, the structure in the first passage P1, which allows the refrigerant to flow through multiple parallel-configured (parallel-connected) flat porous tubes 110, is not limited to the structure described above. For example, in the first passage P1, as... Figure 10 As shown, the refrigerant can also flow through the third and fourth layers of flat porous tubes 110 arranged in parallel from the bottom in a heat exchange section 100, after flowing through the lowest and second layers of the parallel-arranged flat porous tubes 110.

[0184] The structure of Modification A can be applied not only to cases where there are multiple rows of heat exchange section 100, but also to cases where there is only one row of heat exchange section 100.

[0185] (7-2) Variation B The first passage P1 described in the above embodiment may also be configured only on the upwind side of the airflow direction A where frost or ice is particularly prone to problems. For example, in the above embodiment, the first passage P1 may also be configured only in the heat exchange section 100u.

[0186] In the case where the first passage P1 is configured only in the heat exchange section 100u, the structure of the heat exchange section 100 described in Modification A can be applied, for example.

[0187] In addition, if the first passage P1 is configured only in the heat exchange section 100u, the first heat exchanger 11 can be designed as follows: after the refrigerant flows through the first passage P1, it flows in the distributor 170 and then flows in the second passage P2, which includes all the flat porous tubes 110 of the heat exchange section 100d and the flat porous tubes 110 of the heat exchange section 100u except for the first tube group 114.

[0188] (7-3) Variation C In the above embodiment, in order to suppress excessive pressure loss, the refrigerant flows in a plurality of flat porous tubes 110 arranged in parallel in the first passage P1.

[0189] However, the structure of the first passage P1 used to suppress excessive pressure loss is not limited to such a structure. For example, in order to suppress excessive pressure loss in the first passage P1, the flow path area of ​​each of the flat porous tubes 110 in the first tube group 114 can be larger than the flow path area of ​​each of the flat porous tubes 110 in the second tube group 116. Specifically, the flat porous tubes constituting the first passage P1 can also be as follows: Figure 11 Like the flat porous tube 110a of the heat exchange section 100u, a flat porous tube with a larger size of hole 112 and a greater number of holes 112 compared to other flat porous tubes 110 is used. Alternatively, in the flat porous tube 110a, only one of the following structures may be used: one with a larger size of hole 112 than other flat porous tubes 110, and the other with a greater number of holes 112 than other flat porous tubes 110.

[0190] In addition, Figure 10 The example described is the case where the first passage P1 is configured only in the heat exchange section 100u.

[0191] (7-4) Variation D In the above embodiments, the pressure loss section is a distributor 170 or a throttling section 171a provided in the piping 171, but the pressure loss section may also be a nozzle disposed inside the manifold. Specifically, the pressure loss section may also be a nozzle 154 disposed in the space 152c of the first manifold 150.

[0192] To explain in more detail, such as Figure 12 As shown, the first heat exchanger 11 can also be configured within the space 152c of the first manifold 150 as follows: when the first heat exchanger 11 functions as an evaporator, the refrigerant flowing in from the piping 176 is blown upwards through the nozzle 154, causing the refrigerant to circulate in the space above as indicated by the arrow, while simultaneously being diverted to the flat porous pipe 110 communicating with the space 152c. Furthermore, the first heat exchanger 11 can also be designed to generate the desired pressure loss through the nozzle 154.

[0193] (7-5) Variation E In the above embodiment, all the refrigerant flowing into the first heat exchanger 11 is directed to the first passage P1.

[0194] However, with the increasing size of refrigeration cycle devices using heat exchangers, the amount of refrigerant flowing into the heat exchanger is extremely large. If all the refrigerant is to flow to the first passage P1, the pressure loss generated in the first passage P1 may become excessive. If the number of flat porous tubes 110 in the first tube group 114 is increased so that the refrigerant flows through multiple flat porous tubes 110 connected in parallel, the pressure loss generated in the first passage P1 can be suppressed. However, in such a structure, the number of flat porous tubes 110 belonging to the second passage P2, which mainly contributes to heat exchange, is reduced, and the efficiency of the refrigeration cycle device may decrease.

[0195] Therefore, as Figure 13 As shown, the heat exchanger HEX of this disclosure can also have a bypass path that guides the refrigerant to the second path P2 without flowing through the first path P1. Additionally, in Figure 13 In this circuit, the path that flows through the first path P1 and then through the splitter 170 to the second path P2 is called the main path M, and the path that flows through the splitter 170 to the second path P2 without passing through the first path P1 is called the bypass path B.

[0196] Furthermore, while it is preferable to suppress the amount of refrigerant flowing into the first passage P1 in order to suppress pressure loss in the first passage P1, from the viewpoint of suppressing frost formation, it is preferable that a larger amount of refrigerant flows into the first passage P1. Therefore, it is preferable that at least 50% of the refrigerant supplied to the heat exchanger HEX flows into the first passage P1. More preferably, at least 70% of the refrigerant supplied to the heat exchanger HEX flows into the first passage P1.

[0197] In this heat exchanger HEX, even when a large amount of refrigerant is supplied to the heat exchanger HEX, it is possible to suppress the adverse situation where the pressure loss becomes too large due to all the refrigerant flowing through the first passage P1, and the efficiency of the air conditioning unit 1 using the heat exchanger HEX decreases.

[0198] <Postscript> The embodiments of this disclosure have been described above. However, it should be understood that various changes can be made to the manner and details without departing from the spirit and scope of this disclosure as set forth in the claims.

[0199] Label Explanation 1. Air conditioning unit (refrigeration cycle unit) 6 refrigerant circuit 8 compressors 11. First heat exchanger (heat exchanger) 15. First Fan (Blower) 110 flat porous tube 110a flat porous tube (flat porous tube of the first tube group) 110L flat porous tubes are configured at the bottom layer 114 First Pipe Group 116 Second Pipe Group 150 First manifold (manifold) 154 Nozzle (Pressure Loss Section) 170 shunt (pressure loss section) 171a Throttling Section (Pressure Loss Section) 173 Throttling section (pressure loss section) 174a Throttling Section (Pressure Loss Section) 176a Throttling Section (Pressure Loss Section) A. Airflow direction B bypass path P1 First Pathway P2 Second Pathway Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2019-60596

Claims

1. A heat exchanger (11) comprising: a plurality of flat porous tubes (110) arranged in a vertical direction; and a pressure loss section (154, 170, 171a, 173, 174a, 176a) for refrigerant flow, wherein, The plurality of flat porous tubes includes: the flat porous tubes of a first tube group (114), which includes the flat porous tubes disposed at the bottom layer of the heat exchanger; and the flat porous tubes of a second tube group (116) other than the flat porous tubes of the first tube group. The flat porous tube of the first tube assembly forms a first passage (P1) as a flow path for the refrigerant. The flat porous tube of the second tube assembly forms a second passage (P2) as a flow path for the refrigerant. When the heat exchanger functions as an evaporator, at least a portion of the refrigerant supplied to the heat exchanger flows into the pressure loss section after passing through the first passage, and then flows into the second passage after passing through the pressure loss section.

2. The heat exchanger according to claim 1, wherein, When the heat exchanger functions as an evaporator, all of the refrigerant supplied to the heat exchanger flows into the pressure loss section after passing through the first passage, and then flows into the second passage after passing through the pressure loss section.

3. The heat exchanger according to claim 1 or 2, wherein, The first tube group comprises a plurality of the flat porous tubes arranged side by side.

4. The heat exchanger according to claim 1 or 2, wherein, The flow path area of ​​each of the flat porous tubes (110a) in the first tube group is greater than the flow path area of ​​each of the flat porous tubes (110) in the second tube group.

5. The heat exchanger according to any one of claims 1 to 4, wherein, The first tube group contains fewer flat porous tubes than the second tube group contains.

6. The heat exchanger according to any one of claims 1 to 5, wherein, The pressure loss section is a throttling section (171a, 173, 174a, 176a) of the refrigerant flow path disposed between the first passage and the second passage.

7. The heat exchanger according to any one of claims 1 to 5, wherein, The pressure loss section is a flow divider (170) of the refrigerant flow path disposed between the first passage and the second passage.

8. The heat exchanger according to any one of claims 1 to 5, wherein, The heat exchanger also includes a manifold (150) disposed in the refrigerant flow path between the first passage and the second passage. The pressure loss section is a nozzle (154) disposed inside the manifold.

9. The heat exchanger according to claim 1, wherein, The heat exchanger also includes a bypass path (B) that directs the refrigerant to the second path without flowing through the first path.

10. The heat exchanger according to any one of claims 1 to 9, wherein, The flat porous tubes are arranged in multiple rows in the direction (A) of the airflow generated by the blower that supplies air to the heat exchanger. The first passage is configured only on the upwind side in the direction of the airflow.

11. A refrigeration cycle device (1), comprising: Refrigerant circuit (6), comprising a heat exchanger as described in any one of claims 1 to 10 as a heat source heat exchanger and a compressor (8) for compressing the refrigerant; and A blower (15) supplies air to the heat exchanger.

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