Refrigeration cycle equipment

Abstract

This disclosure provides a refrigeration cycle device that is easy to improve performance with. [Solution] The refrigeration cycle device in this disclosure comprises a compressor, a switching unit that switches between cooling operation and heating operation by switching the flow path of a working medium, a heat source side heat exchanger, an expansion valve, and a utilization side heat exchanger, wherein the heat source side heat exchanger and the utilization side heat exchanger are provided with a flow straightening unit that aligns the direction of the flow of the working medium between cooling operation and heating operation and causes the working medium and air to flow in opposite directions, and at least one of the heat source side heat exchanger and the utilization side heat exchanger comprises a plurality of heat transfer tubes and a first header connected to the upstream side of the plurality of heat transfer tubes in the flow of the working medium, wherein the first header has an internal distribution mechanism that equalizes the working medium distributed to the plurality of heat transfer tubes.

Description

Technical Field

[0001] The present disclosure relates to a refrigeration cycle apparatus.

Background Art

[0002] Patent Document 1 discloses a refrigeration cycle apparatus that causes air and a refrigerant to exchange heat in a counterflow in both a cooling case and a heating case. This refrigeration cycle apparatus includes two bridge circuits configured such that the flow of the refrigerant is in the same direction in both the heating operation and the heating operation for each of the indoor heat exchanger and the outdoor heat exchanger.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] The present disclosure provides a refrigeration cycle apparatus that facilitates improvement of performance.

Means for Solving the Problem

[0005] A refrigeration cycle apparatus according to the present disclosure includes a compressor, a switching unit that switches between a cooling operation and a heating operation by switching a flow path of a working medium, a heat source-side heat exchanger, an expansion valve, and a utilization-side heat exchanger, and further includes a rectifying unit that makes the direction of the flow of the working medium identical between the cooling operation and the heating operation in the heat source-side heat exchanger and the utilization-side heat exchanger, and causes the working medium and air to form a counterflow, wherein at least one of the heat source-side heat exchanger and the utilization-side heat exchanger includes a plurality of heat transfer tubes, and a first header connected to an upstream side of the plurality of heat transfer tubes in the flow of the working medium, and the first header internally has a distribution mechanism that equalizes the working medium to be distributed to the plurality of heat transfer tubes.

Effects of the Invention

[0006] The refrigeration cycle system in this disclosure can equalize the distribution of the working fluid to each heat transfer tube in the heat exchanger, even when the operating mode is switched and the state of the working fluid flowing through the heat exchanger equipped with the first header (among the user-side heat exchanger and the heat source-side heat exchanger) changes. Therefore, the heat exchange between the working fluid and air can be made more efficient, and the performance of the refrigeration cycle system can be easily improved. [Brief explanation of the drawing]

[0007] [Figure 1] Diagram showing the refrigerant circuit of the air conditioning system according to Embodiment 1. [Figure 2] Perspective view of a heat exchanger according to Embodiment 1 [Figure 3] Cross-sectional view of the heat exchanger in Figure 2. [Figure 4] IV cross-sectional view of the heat exchanger in Figure 2. [Figure 5] Perspective view of a heat exchanger according to Embodiment 2 [Figure 6] Cross-sectional view of VI in Figure 5 [Modes for carrying out the invention]

[0008] (Knowledge and other information that formed the basis of this disclosure) At the time the inventors conceived this disclosure, as described in Patent Document 1, a technique had been proposed to improve the performance of a refrigeration cycle system by providing headers at the inlet and outlet of a heat exchanger and creating counterflow between the working fluid and air in the heat exchanger for both cooling and heating. However, when the heat exchanger functions as an evaporator, the refrigerant flows into the header in a liquid or gas-liquid two-phase state, which can lead to poor flow separation from the header to the heat transfer tubes. Furthermore, if a distributor or the like is provided upstream of the heat exchanger instead of a header to improve flow separation, the refrigerant flows into the heat exchanger from the same direction for both cooling and heating. As a result, when the heat exchanger functions as a condenser, the working fluid in a gaseous state flows into the distributor or the like, leading to a large pressure loss. Therefore, the inventors discovered that it had not been possible to achieve both counterflow for both cooling and heating in the heat exchanger and ensure proper flow separation, and that there was room for improvement to enhance system performance. To solve this problem, the subject of this disclosure was formed. Therefore, this disclosure provides a refrigeration cycle device that is easy to improve performance with.

[0009] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The attached drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) Embodiment 1 will be described below with reference to the drawings.

[0011] [1-1. Structure] [1-1-1. Overall configuration of the refrigerant circuit] Figure 1 shows the refrigerant circuit 1A of the air conditioning system 1 according to Embodiment 1. In Figure 1, the solid arrows indicate the direction of the working fluid flow during heating operation, and the dashed arrows indicate the direction of the working fluid flow during cooling operation.

[0012] The air conditioning system 1 comprises an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 is a device mainly installed outdoors, such as in a building. The indoor unit 3 is a device that mainly discharges warm or cool air into the indoor space of a building, etc., to conditioned the air in the indoor space. The air conditioning system 1 corresponds to an example of a "refrigeration cycle system" in this disclosure.

[0013] As shown in Figure 1, the air conditioning system 1 is formed by connecting the outdoor unit 2 and the indoor unit 3 by an internal-to-external gas pipe 4 and an internal-to-external liquid pipe 5, and has a refrigerant circuit 1A in which a working medium circulates. In this embodiment, the inside of the refrigerant circuit 1A is filled with a non-azeotropic mixed refrigerant as the working medium. Specifically, as the non-azeotropic mixed refrigerant, for example, a mixture of CO2 (carbon dioxide), HFC32 (R32), and HFO1234ZE (R1234ZE) in a predetermined ratio can be used.

[0014] The outdoor unit 2 has a compressor 21. The compressor 21 draws in a gaseous working medium from an intake pipe 21A connected to the intake port and compresses it. The compressor 21 discharges the compressed high-temperature, high-pressure gaseous working medium to a discharge pipe 21B connected to the discharge port.

[0015] The suction pipe 21A and the discharge pipe 21B are connected to the switching unit 22. In the present embodiment, the switching unit 22 is a four-way valve. The switching unit 22 is connected to the first gas pipe 23 and the second gas pipe 24 in addition to the suction pipe 21A and the discharge pipe 21B. The switching unit 22 switches the operation mode of the air conditioner 1 between the cooling operation and the heating operation by switching the flow path. Specifically, the switching unit 22 switches the operation mode of the air conditioner 1 to the cooling operation by bringing the discharge pipe 21B into communication with the second gas pipe 24 and bringing the suction pipe 21A into communication with the first gas pipe 23. Further, the switching unit 22 switches the operation mode of the air conditioner 1 to the heating operation by bringing the discharge pipe 21B into communication with the first gas pipe 23 and bringing the suction pipe 21A into communication with the second gas pipe 24. The cooling operation corresponds to an example of the "cooling operation" in the present disclosure. The heating operation corresponds to an example of the "heating operation" in the present disclosure.

[0016] The first gas pipe 23 is a pipe through which a gaseous working medium flows. The first gas pipe 23 connects the switching unit 22 and the indoor-outdoor connection gas pipe 4. The indoor-outdoor connection gas pipe 4 is a pipe through which a gaseous working medium flows, and connects the outdoor unit 2 and the indoor unit 3.

[0017] The second gas pipe 24 is a pipe through which a gaseous working medium flows. The second gas pipe 24 is connected to the heat source side rectifying unit 25. In the present embodiment, the heat source side rectifying unit 25 is a four-way valve. The heat source side rectifying unit 25 is connected to the first heat source side pipe 26, the second heat source side pipe 27, and the heat source side liquid pipe 28 in addition to the second gas pipe 24. The first heat source side pipe 26 and the second heat source side pipe 27 are pipes that connect the heat source side rectifying unit 25 and the heat source side heat exchanger 50S, respectively. The interiors of the first heat source side pipe 26 and the second heat source side pipe 24 communicate with each other via the interior of the heat source side heat exchanger 50S. The heat source side rectifying unit 25 corresponds to an example of the "rectifying unit" in the present disclosure.

[0018] Furthermore, the first heat source side pipe 26 branches into a plurality of paths from the heat source side rectifying unit 25 side toward the heat source side heat exchanger 50S side. In the present embodiment, the first heat source side pipe 26 branches into two paths, namely a first heat source side branch part 26A and a second heat source side branch part 26B, from the heat source side rectifying unit 25 side toward the heat source side heat exchanger 50S side. Each of the first heat source side branch part 26A and the second heat source side branch part 26B is connected to the heat source side heat exchanger 50S. Further, the first heat source side branch part 26A is provided with a heat source side switching valve 26C. The heat source side switching valve 26C is a valve that can be switched between an open state and a closed state by control. When in the closed state, the heat source side switching valve 26C blocks the flow of the working medium in the first heat source side branch part 26A, and when in the open state, it does not block the flow of the working medium in the first heat source side branch part 26A. By switching between the open state and the closed state, the heat source side switching valve 26C switches the flow of the working medium to the inlets 52A, 59A of the respective medium flow paths S1, S2, which will be described later and are provided in the heat source side heat exchanger 50S. A part or all of the first heat source side branch part 26A, the second heat source side branch part 26B, and the heat source side switching valve 26C may be configured to be included in the heat source side heat exchanger 50S. The heat source side switching valve 26C corresponds to an example of the "switching valve" in the present disclosure.

[0019] The heat source side rectifying unit 25 causes the working medium that has flowed in from the second gas pipe 24 or the heat source side liquid pipe 28 to flow into the first heat source side pipe 25 during both heating operation and cooling operation. Further, the working medium flows into the heat source side rectifying unit 25 from the second heat source side pipe 27 during both heating operation and cooling operation, and the flowed-in working medium is caused to flow into the second gas pipe 24 or the heat source side liquid pipe 28. That is, the heat source side rectifying unit 25 makes the direction of the flow of the working medium in the first heat source side pipe 26, the second heat source side pipe 27, and the heat source side heat exchanger 50S consistent between the cooling operation and the heating operation of the air conditioner 1. Specifically, during cooling operation, the heat source side rectifying unit 25 communicates the second gas pipe 24 with the first heat source side pipe 26, and communicates the second heat source side pipe 27 with the heat source side liquid pipe 28. Further, during heating operation, the heat source side rectifying unit 25 communicates the second gas pipe 24 with the second heat source side pipe 27, and communicates the first heat source side pipe 26 with the heat source side liquid pipe 28.

[0020] The heat source side liquid pipe 28 is a pipe that connects the heat source side rectifier 25 and the internal / external connecting liquid pipe 5. The internal / external connecting liquid pipe 5 is a pipe that connects the heat source side liquid pipe 28 of the outdoor unit 2 and the utilization side liquid pipe 31 of the indoor unit 3. A working fluid in a liquid state or a gas-liquid two-phase state flows inside the heat source side liquid pipe 28, the internal / external connecting liquid pipe 5, and the utilization side liquid pipe 31.

[0021] An expansion valve 32 is provided in the liquid pipe 31 on the user side. The expansion valve 32 is a valve that reduces the pressure of the liquid working medium flowing inside the liquid pipe 31 on the user side, creating a gas-liquid two-phase state. The expansion valve 32 is configured so that its opening degree can be changed by control.

[0022] The user-side liquid pipe 31 is connected to the user-side rectifier 33. In this embodiment, the user-side rectifier 33 is a four-way valve. In addition to the user-side liquid pipe 31, the user-side rectifier 33 is connected to the first user-side piping 34, the second user-side piping 35, and the user-side gas pipe 36. The user-side gas pipe 36 is a pipe connected to the aforementioned internal / external connecting gas pipe 4 in the indoor unit 3, and a gaseous working medium flows through its interior. The first user-side piping 34 and the second user-side piping 35 are pipes that connect the user-side rectifier 33 and the user-side heat exchanger 50U, respectively. The interiors of the first user-side piping 34 and the second user-side piping 35 are in communication via the interior of the user-side heat exchanger 50U. The user-side rectifier unit 33 corresponds to an example of a "rectifier unit" in this disclosure.

[0023] Furthermore, the first user-side piping 34 branches into multiple branches from the user-side rectifier 33 side toward the user-side heat exchanger 50U side. In this embodiment, the first user-side piping 34 branches into two branches, the first user-side branch 34A and the second user-side branch 34B, from the user-side rectifier 33 side toward the user-side heat exchanger 50U side. The first user-side branch 34A and the second user-side branch 34B are each connected to the user-side heat exchanger 50U. In addition, a user-side switching valve 34C is provided in the first user-side branch 34A. The user-side switching valve 34C is a valve that can be switched between an open state and a closed state by control. When the user-side switching valve 34C is in the closed state, it blocks the flow of the working medium in the first user-side branch 34A, and when it is in the open state, it does not block the flow of the working medium in the first user-side branch 34A. The user-side switching valve 34C switches the flow of the working fluid to the inlets 52A and 59A of the respective fluid flow paths S1 and S2, described later, provided in the user-side heat exchanger 50U, by switching between an open state and a closed state. Note that some or all of the first user-side branch section 34A, the second user-side branch section 34B, and the user-side switching valve 34C may be included in the user-side heat exchanger 50U. The user-side switching valve 34C corresponds to an example of a "switching valve" in this disclosure.

[0024] The user-side rectifier 33 directs the working fluid flowing in from the user-side liquid pipe 31 or user-side gas pipe 36 into the first user-side piping 34 during both heating and cooling operations. Furthermore, the user-side rectifier 33 receives working fluid from the second user-side piping 35 during both heating and cooling operations, directing the incoming working fluid into the user-side liquid pipe 31 or user-side gas pipe 36. In other words, the user-side rectifier 33 ensures that the flow direction of the working fluid in the first user-side piping 34, the second user-side piping 35, and the user-side heat exchanger 50U is consistent between the cooling and heating operations of the air conditioner 1. More specifically, during heating operation, the user-side rectifier 33 connects the first user-side piping 34 and the user-side gas pipe 36, and connects the user-side liquid pipe 31 and the second user-side piping 35. Furthermore, during cooling operation, the user-side rectifier 33 connects the user-side liquid pipe 31 to the first user-side piping 34, and connects the second user-side piping 35 to the user-side gas pipe 36.

[0025] Furthermore, the outdoor unit 2 has a heat source side blower 29. Similarly, the indoor unit 3 has a utilization side blower 37. The heat source side blower 29 and the utilization side blower 37 are blowers that transport air. The heat source side blower 29 transports air from the outside outside the outdoor unit 2, draws it into the outdoor unit 2 through the heat source side heat exchanger 50S, and blows it out to the outside of the outdoor unit 2. The utilization side blower 37 transports air from the inside outside the indoor unit 3, draws it into the indoor unit 3, passes it through the utilization side heat exchanger 50U, and then blows it out to the inside outside the indoor unit 3. The heat source side blower 29 and the utilization side blower 37 may be any type of blower, such as an axial flow fan, centrifugal fan, or cross-flow fan.

[0026] Furthermore, the air conditioning system 1 has a control unit 70. The control unit 70 is connected to various parts of the air conditioning system 1, such as the compressor 21, and controls these parts to perform various processes in the air conditioning system 1. In this embodiment, the control unit 70 is provided in the outdoor unit 2.

[0027] In this embodiment, the control unit 70 comprises a processor and a storage medium, and the processor reads and executes a program stored in the storage medium to perform various processing for the air conditioner 1. The processor that the control unit 70 may include is, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage medium that the control unit 70 may include is, for example, a hard disk, flash memory, or optical disc. The control unit 70 may be installed in either the indoor unit 3 or the outdoor unit 2, or it may be installed outside the indoor unit 3 and the outdoor unit 2. Alternatively, the control unit 70 may function through the cooperation of the indoor unit 3, the outdoor unit 2, and a plurality of components, circuits, etc. installed outside them.

[0028] [1-1-2. Configuration near the heat exchanger] Figure 2 is a perspective view of the heat exchanger 50, showing the heat exchanger 50 viewed from diagonally below. In Figure 2, the dashed arrows indicate the direction of the working fluid flow during cooling and heating operations. The white arrows indicate the direction of airflow driven by the heat source side blower 29 or the user side blower 37.

[0029] In this embodiment, the same design of heat exchangers is used as the heat source side heat exchanger 50S and the utilization side heat exchanger 50U. When the heat source side heat exchanger 50S and the utilization side heat exchanger 50U are not distinguished, they are referred to as heat exchanger 50. The heat source side heat exchanger 50S and the utilization side heat exchanger 50U correspond to examples of "heat exchangers" in this disclosure.

[0030] The heat exchanger 50 has a plurality of inlet pipes 51. Each inlet pipe 51 is connected at one end to either the first heat source side piping 26 or the first utilization side piping 34. That is, during both cooling and heating operation, the working fluid flows into the inlet pipes 51 from either the first heat source side piping 26 or the first utilization side piping 34.

[0031] In this embodiment, the heat exchanger 50 has two inlet pipes 51. More specifically, the heat exchanger 50 has a first inlet pipe 51A with a larger inner diameter and a second inlet pipe 51B with a smaller inner diameter than the first inlet pipe 51A. The first inlet pipe 51A and the second inlet pipe 51B correspond to examples of "inlet pipes" in this disclosure.

[0032] As shown in Figure 1, the first inlet pipe 51A of the heat source side heat exchanger 50S is connected to the first heat source side branch section 26A. The first inlet pipe 51A of the utilization side heat exchanger 50U is connected to the first utilization side branch section 34A. In other words, the first inlet pipe 51A is located downstream of the heat source side switching valve 26C or the utilization side switching valve 34C in the flow of the working fluid. Also, the second inlet pipe 51B of the heat source side heat exchanger 50S is connected to the second utilization side branch section 34B. The second inlet pipe 51B of the utilization side heat exchanger 50U is connected to the second utilization side branch section 34B.

[0033] As shown in Figure 2, the heat exchanger 50 has a first header 52. The first header 52 is a long, slender, hollow cylindrical member that extends in a straight line, with both ends closed in the longitudinal direction, the first direction D1. In this embodiment, the first direction D1 is the horizontal direction, and the first header 52 is positioned to extend along the horizontal direction. As shown in Figure 2, each of the inlet pipes 51 extends outward from the first header 52. That is, the first header 52 of each heat exchanger 50S, 50U is connected to each switching valve 26C, 34C via the first inlet pipe 51A.

[0034] The heat exchanger 50 has a plurality of upstream heat transfer tubes 53. Each upstream heat transfer tube 53 is a pipe with one end connected to a first header 52, through which a working medium flows in from the first header 52. The upstream heat transfer tube 53 exchanges heat between the working medium flowing inside and the air surrounding the upstream heat transfer tube 53. The upstream heat transfer tube 53 extends along a second direction D2 perpendicular to a first direction D1. In this embodiment, the second direction D2 is the vertical direction, and the upstream heat transfer tube 53 extends upward from the first header 52. The plurality of upstream heat transfer tubes 53 are arranged at equal intervals along the first direction D1. The upstream heat transfer tube 53 corresponds to an example of a "heat transfer tube" in this disclosure.

[0035] As described above, one end of each of the multiple upstream heat transfer tubes 53 is connected to the first header 52. The first header 52 functions as a flow shunt that distributes the working fluid to each of the upstream heat transfer tubes 53. The first header 52 corresponds to an example of a “distributor” in this disclosure.

[0036] Furthermore, in this embodiment, the upstream heat transfer tube 53 has a flattened tube shape in a cross-section perpendicular to the second direction D2. Specifically, the cross-sectional shape of the upstream heat transfer tube 53 in a cross-section perpendicular to the second direction D2 is a substantially rectangular shape with the short side aligned with the first direction D1 and the long side aligned with the third direction D3. The third direction D3 is a direction perpendicular to the first direction D1 and the second direction D2, and in this embodiment, it is a horizontal direction. This makes it easier for air to pass between the upstream heat transfer tubes 53 along the third direction D3, and also increases the surface area of ​​the upstream heat transfer tube 53 compared to the case of a circular cross-section, thus facilitating heat exchange between the working medium and the air. In addition, in this embodiment, multiple microchannels are formed inside the upstream heat transfer tube 53 as flow paths for the working medium, making it easier to further promote heat exchange between the working medium and the air.

[0037] The heat exchanger 50 has a plurality of fins 54. The fins 54 are made of thin metal plates. The fins 54 promote heat exchange between the working medium in the upstream heat transfer tubes 53 and the air by increasing the surface area in contact with the air. Each surface of the fins 54 is substantially parallel to the third direction D3. As a result, a plurality of gaps are formed between the upstream heat transfer tubes 53 that allow air to pass along the third direction D3. In this embodiment, the fins 54 are corrugated fins made of metal plates bent into a wave shape.

[0038] The heat exchanger 50 has an intermediate header 55. The intermediate header 55 is a long, slender, hollow member connected to the other end of each upstream heat transfer tube 53. The interior of the intermediate header 55 communicates with the interior of the upstream heat transfer tube 53. The intermediate header 55, like the first header 52, is positioned with its longitudinal direction aligned with the first direction D1. Furthermore, the position occupied by the intermediate header 55 in the first direction D1 is approximately the same as the position occupied by the first header 52.

[0039] The heat exchanger 50 has a plurality of downstream heat transfer tubes 56. The downstream heat transfer tubes 56 are pipes with one end connected to an intermediate header 55, through which the working fluid flowing in from the intermediate header 55 flows. As described above, in the heat source side heat exchanger 50S and the user side heat exchanger 50U, during both heating and cooling operations, the working fluid flows in the following order from upstream: inlet pipe 51, first header 52, upstream heat transfer tube 53, intermediate header 55, and downstream heat transfer tube 56. Thus, the downstream heat transfer tubes 56 are located downstream of the upstream heat transfer tubes 53 in the flow of the working fluid during both cooling and heating operations.

[0040] The downstream heat transfer tube 56 exchanges heat between the working fluid flowing inside it and the air surrounding the downstream heat transfer tube 56. The downstream heat transfer tube 56 extends along the second direction D2, substantially parallel to the upstream heat transfer tube 53. In this embodiment, the downstream heat transfer tube 56 extends downward from the intermediate header 55. In addition, multiple downstream heat transfer tubes 56 are arranged at equal intervals along the first direction D1. The downstream heat transfer tube 56 corresponds to an example of a "heat transfer tube" in this disclosure.

[0041] Each downstream heat transfer tube 56 is positioned on one side of the third direction D3, towards direction D31, compared to each upstream heat transfer tube 53. Furthermore, the downstream heat transfer tubes 56 are positioned so as to substantially overlap with the upstream heat transfer tubes 53 when viewed along the third direction D3.

[0042] Furthermore, in this embodiment, similar to the upstream heat transfer tube 53, the downstream heat transfer tube 56 is a flattened tube shape, and the cross-sectional shape of the downstream heat transfer tube 56 in a cross section perpendicular to the second direction D2 is a substantially rectangular shape with the short side aligned with the first direction D1 and the long side aligned with the third direction D3. In addition, the fins 54 described above are provided between the downstream heat transfer tubes 56 in the second direction D2, with each surface facing the third direction D3. As a result, multiple gaps are formed between the downstream heat transfer tubes 56 that allow for ventilation along the third direction D3.

[0043] The heat exchanger 50 has a second header 57. The second header 57 is an elongated, hollow, cylindrical member connected to the other end of each downstream heat transfer tube 56, with both ends in the longitudinal direction closed. Since the interior of the second header 57 is in communication with the interior of each downstream heat transfer tube 56, the working fluid that has flowed through each downstream heat transfer tube 56 flows into the interior of the second header 57. The second header 57 is positioned substantially parallel to the first header 52 with its longitudinal direction aligned with the first direction D1, and in this embodiment, the second header extends along the horizontal direction. The second header 57 is also provided at a position spaced apart from the first header 52 towards one side of the third direction D3, towards direction D31. Furthermore, in the first direction D1, the position occupied by the second header 57 substantially coincides with the positions occupied by the first header 52 and the intermediate header 55.

[0044] The heat exchanger 50 has an outlet pipe 58. The outlet pipe 58 is a pipe connected at one end to the second header 57, and the working medium that has flowed through the second header 57 flows into it. As shown in Figure 1, the outlet pipe 58 of the heat source side heat exchanger 50S is connected at the other end to the second heat source side piping 27. The outlet pipe 58 of the utilization side heat exchanger 50U is connected at the other end to the second utilization side piping 35.

[0045] Each of the heat exchangers 50S and 50U configured in this way is positioned and positioned such that the air transported to each of the blowers 29 and 37 passes through the gaps between the upstream heat transfer tubes 53 and between the downstream heat transfer tubes 56 in the other direction D32 in the third direction D3, as shown by the white arrows in Figure 2. That is, in each of the heat exchangers 50S and 50U, the upstream side in the airflow is the direction D31 side, and the downstream side is the direction D32 side.

[0046] In contrast, as described above, the downstream heat transfer tube 56, which is located in the direction D31 upstream of the upstream heat transfer tube 53 in the airflow, is located downstream of the upstream heat transfer tube 53 in the working fluid flow. That is, in each heat exchanger 50S and 50U, the upstream direction in the working fluid flow and the upstream direction in the airflow are opposite directions, and the working fluid and air are in counterflow. In other words, each heat exchanger 50S and 50U is positioned and positioned such that the working fluid and air are in counterflow.

[0047] Figure 3 is a cross-sectional view III of the heat exchanger 50 in Figure 2, showing a cross section that passes through the center of the first header 52 and is perpendicular to the third direction D3. Figure 4 is a cross-sectional view IV of the heat exchanger 50 in Figure 2, showing a cross section that passes through the first header 52 and the second header 57 and is perpendicular to the first direction D1.

[0048] As shown in Figure 3, a first inlet 52A is formed in the first header 52. The first inlet 52A is an opening in the first header 52 to which the first inlet pipe 51A is connected. In addition, a plurality of first outlets 52B are formed in the first header 52. Each first outlet 52B is an opening to which one end of each upstream heat transfer tube 53 is connected. The first inlet 52A corresponds to an example of an "inlet" in this disclosure. The first outlet 52B corresponds to an example of an "outlet" in this disclosure.

[0049] Furthermore, a distribution mechanism 59 is provided inside the first header 52. The distribution mechanism 59 is a component that equalizes the working medium distributed from the first header 52 to each upstream heat transfer tube 53. Specifically, the distribution mechanism 59 mainly equalizes the ratio of liquid working medium to gaseous working medium in the gas-liquid two-phase working medium distributed to each upstream heat transfer tube 53. In this specification, "equalization" means reducing the variation (e.g., dispersion) in the ratio of liquid working medium to gaseous working medium among each upstream heat transfer tube 53. In other words, the distribution mechanism 59 only needs to be able to reduce the variation in the ratio of liquid working medium to gaseous working medium among each upstream heat transfer tube 53 compared to a case where the distribution mechanism 59 is not provided.

[0050] The distribution mechanism 59 partitions the space inside the first header 52, forming multiple media flow paths S. Each media flow path S is a space inside the first header 52 through which the working medium can flow.

[0051] In this embodiment, the distribution mechanism 59 is a hollow cylindrical member that extends parallel to the first header 52 along the first direction D1. Furthermore, as shown in Figure 3, both ends of the distribution mechanism 59 in the first direction D1 are connected to the wall surfaces at both ends of the first header 52 in the first direction D1, thus closing it off. Moreover, as shown in Figure 4, when viewed along the first direction D1, the center of the distribution mechanism 59 substantially coincides with the center of the first header 52.

[0052] Therefore, a first medium flow path S1 is formed between the inner surface of the first header 52 and the outer surface of the distribution mechanism 59, which is a medium flow path S connected to the first inlet pipe 51A via the first inlet 52A and connected to the multiple upstream heat transfer tubes 53 via the multiple first outlets 52B. In other words, the first medium flow path S1 has a first inlet 52A and a first outlet 52B. The first medium flow path S1 is a space formed between the inner surface of the first header 52 and the outer surface of the distribution mechanism 59. The first medium flow path S1 is formed with the first direction D1 as its longitudinal direction. In this embodiment, the first medium flow path S1 extends along the entire length of the first header 52 in the first direction D1 and is an annular space when viewed along the first direction D1.

[0053] Furthermore, a second media channel S2, which is a media channel S partitioned inside the distribution mechanism 59, is formed inside the first header 52. The second media channel S2 is formed inside the first media channel S1. The second media channel S2 is formed with the first direction D1 as its longitudinal direction. In this embodiment, the second media channel S2 extends along the entire length of the first header 52 in the first direction D1 and is a circular space when viewed along the first direction D1. Also, the second media channel S2 is surrounded on its entire circumference by the first media channel S1 when viewed along the first direction D1.

[0054] A second inlet 59A is formed in the distribution mechanism 59. The second inlet 59A is an opening to which the second inlet pipe 51B is connected. The second inlet pipe 51B penetrates the wall of the first header 52 and is connected to the second inlet 59A. Therefore, the space inside the second inlet pipe 51B is not directly connected to the first media flow path S1, but is directly connected to the second media flow path S2. The second inlet 59A corresponds to an example of an "inlet" in this disclosure.

[0055] Furthermore, the distribution mechanism 59 has multiple second outlets 59B. The second outlets 59B are openings that connect the second medium flow path S2 inside the distribution mechanism 59 and the first medium flow path S1 outside the distribution mechanism 59. Thus, the second medium flow path S2 is connected to multiple upstream heat transfer tubes 53 via the second outlets 59B and the first medium flow path S1. In this way, the second medium flow path S2 has a second inlet 59A and a second outlet 59B. The second outlet 59B corresponds to an example of an "outlet" in this disclosure.

[0056] In this embodiment, the multiple second outlets 59B are arranged at equal intervals along the first direction D1 and are provided over substantially the entire length of the distribution mechanism 59 in the first direction D1. Furthermore, the opening area of ​​each second outlet 59B is at least smaller than the inner cross-sectional area of ​​the distribution mechanism 59 in a cross section perpendicular to the first direction D1 (i.e., the cross-sectional area of ​​the second medium flow path S2). In this embodiment, each second outlet 59B opens toward one end of the first outlet 52B and the upstream heat transfer tube 53 when viewed along the first direction D1. In this embodiment, when viewed in the direction in which the upstream heat transfer tube 53 extends, i.e., along the second direction D2, each second outlet 59B is formed at a position that overlaps with each first outlet 52B and each upstream heat transfer tube 53.

[0057] Furthermore, as shown in Figure 4, in a cross-section perpendicular to the first direction D1, the cross-sectional area of ​​the first medium flow path S1 is larger than the cross-sectional area of ​​the second medium flow path S2. In other words, in a cross-section perpendicular to the first direction D1, the cross-sectional area of ​​the first medium flow path S1 is larger than the cross-sectional area of ​​the second medium flow path S2. For this reason, the first medium flow path S1 is a flow path in which the working medium flowing inside experiences less pressure loss than the second medium flow path S2.

[0058] As described above, the first inlet 52A of the first media channel S1, which has a smaller pressure loss than the second media channel S2, is connected to the first inlet pipe 51A, which has a larger inner diameter than the second inlet pipe 51B connected to the second inlet 59A of the second media channel S2. In this way, each inlet pipe 51A and 51B in the heat exchanger 50 is configured such that the smaller the pressure loss of the respective media channels S1 and S2 to which it is connected, the larger the inner diameter.

[0059] Inside the second header 57, a third medium flow path S3 is provided, which is a space through which the working medium flows. The third medium flow path S3 is formed with the first direction D1 as its longitudinal direction. In this embodiment, the third medium flow path S3 is a space with a circular cross-section perpendicular to the first direction D1.

[0060] As shown in Figure 4, the second header 57 is hollow and does not have a distribution mechanism 59 or the like inside. Therefore, the space inside the second header 57 is not partitioned, and the entire space inside the second header 57 forms a single third medium flow path S3. Consequently, almost the entire amount of working medium that flows through the downstream heat transfer tube 56 flows into the third medium flow path S3. Also, almost the entire amount of working medium that flows through the third medium flow path S3 flows into the outlet pipe 58.

[0061] Furthermore, as shown in Figure 4, in a cross-section perpendicular to the first direction D1, the cross-sectional area of ​​the third medium channel S3 is greater than or equal to the cross-sectional areas of the first medium channel S1 and the second medium channel S2, respectively. Therefore, the pressure loss of the working medium in the third medium channel S3 is less than or equal to the pressure loss of the working medium in the first medium channel S1 and the second medium channel S2, respectively. In this embodiment, the cross-sectional area of ​​the third medium channel S3 is larger than that of the first medium channel S1 and the second medium channel S2, respectively, and the pressure loss of the working medium in the third medium channel S3 is smaller than the pressure loss of the working medium in the first medium channel S1 and the second medium channel S2, respectively.

[0062] [1-2. Operation] The operation of the air conditioning system 1, configured as described above, will be explained below.

[0063] [1-2-1. Operation during cooling operation] The air conditioning system 1 performs cooling operation by having the heat source side heat exchanger 50S function as a condenser and the user side heat exchanger 50U function as an evaporator. The operation of the air conditioning system 1 when it performs cooling operation will be described below.

[0064] During cooling operation of the air conditioning unit 1, the control unit 70 switches the flow path of the switching unit 22, connecting the discharge pipe 21B to the second gas pipe 24 and the suction pipe 21A to the first gas pipe 23, as shown by the dashed line in Figure 1. The control unit 70 also switches the flow path of the heat source side rectifier unit 25, connecting the second gas pipe 24 to the first heat source side pipe 26 and the second heat source side pipe 27 to the heat source side liquid pipe 28. As a result, the high-temperature, high-pressure gaseous working fluid discharged to the compressor 21 flows sequentially through the discharge pipe 21B, the switching unit 22, the second gas pipe 24, and the heat source side rectifier unit 25 before flowing into the first heat source side pipe 26.

[0065] Furthermore, the control unit 70 switches the heat source side switching valve 26C to the open state when the air conditioner 1 is in cooling operation. As a result, the working fluid in a high-temperature, high-pressure gaseous state flowing through the first heat source side piping 26 flows into the first inlet pipe 51A of the heat source side heat exchanger 50S via the first heat source side branch section 26A. Note that during cooling operation, the working fluid in the first heat source side piping 26 can also flow into the second inlet pipe 51B via the second heat source side branch section 26B. However, the pressure loss when the working fluid flows through the second inlet pipe 51B and the second fluid flow path S2 is greater than that of the first inlet pipe 51A and the first fluid flow path S1. For this reason, during cooling operation, the working fluid in the first heat source side piping 26 mainly flows into the first heat source side branch section 26A and the first inlet pipe 51A.

[0066] The high-temperature, high-pressure gaseous working medium that flows into the first inlet pipe 51A flows into the first medium flow path S1 inside the first header 52 via the first inlet 52A. The gaseous working medium spreads substantially uniformly throughout the first medium flow path S1 and flows substantially uniformly into each upstream heat transfer tube 53 via each first outlet 52B. As described above, the first inlet pipe 51A and the first medium flow path S1 have a larger cross-sectional area compared to the second inlet pipe 51B and the second medium flow path S2, which reduces the pressure loss of the working medium flowing inside. Therefore, it is easier to reduce the workload of the compressor 21.

[0067] The gaseous working fluid that flows into the upstream heat transfer tube 53 dissipates heat to the air transported by the heat source side blower 29 via the upstream heat transfer tube 53 and fins 54, and flows into the intermediate header 55. The working fluid that flows into the intermediate header 55 flows into each downstream heat transfer tube 56 connected to the intermediate header 55. The working fluid that flows into the downstream heat transfer tube 56 dissipates heat to the air transported by the heat source side blower 29 via the downstream heat transfer tube 56 and fins 54. As described above, the downstream heat transfer tube 56, which is located downstream of the upstream heat transfer tube 53 in the flow of the working fluid, is located upstream of the upstream heat transfer tube 53 in the airflow from the heat source side blower 29, and the working fluid and air in each heat transfer tube 53, 56 are in counterflow. In this embodiment, since the working fluid is a non-azeotropic mixed refrigerant with thermal glide, the efficiency of heat exchange can be improved by making the flow of the working fluid and the flow of air counterflow.

[0068] The working fluid that has flowed through the downstream heat transfer tube 56 enters the third fluid passage S3 of the second header 57 in a liquid state. The working fluid in the liquid state that has entered the second header 57 enters the outlet pipe 58. As described above, the third fluid passage S3 has a larger cross-sectional area compared to the fluid passages S1 and S2 of the first header 52, which reduces the pressure loss of the working fluid flowing inside. Therefore, it is easier to reduce the workload of the compressor 21.

[0069] The liquid working fluid that flows into the outlet pipe 58 of the heat source side heat exchanger 50S flows sequentially through the second heat source side piping 27, the heat source side straightening section 25, the heat source side liquid pipe 28, the internal / external connecting liquid pipe 5, and the utilization side liquid pipe 31, reaching the expansion valve 32. In the expansion valve 32, the liquid working fluid is depressurized and becomes low temperature and in a gas-liquid two-phase state. The gas-liquid two-phase working fluid flows from the utilization side liquid pipe 31 into the utilization side straightening section 33.

[0070] During cooling operation of the air conditioning unit 1, the control unit 70 switches the flow path of the user-side rectifier 33, connecting the user-side liquid pipe 31 with the first user-side piping 34, and connecting the second user-side piping 35 with the user-side gas pipe 36. As a result, the gas-liquid two-phase working fluid that flows from the user-side liquid pipe 31 into the first user-side piping 34 flows into the first user-side piping 34.

[0071] Furthermore, during cooling operation of the air conditioning unit 1, the control unit 70 switches the user-side switching valve 34C to the closed state, blocking the flow of the working fluid in the first user-side branch section 34A. As a result, almost the entire amount of the gas-liquid two-phase working fluid inside the first user-side piping 34 flows through the second user-side branch section 34B and into the second inlet pipe 51B of the user-side heat exchanger 50U.

[0072] The gas-liquid two-phase working fluid that flows into the second inlet pipe 51B flows into the second media flow path S2 inside the distribution mechanism 59 via the second inlet 59A. The working fluid that flows into the second media flow path S2 spreads throughout almost the entire area of ​​the second media flow path S2 and flows into the first media flow path S1 via each second outlet 59B. The working fluid that flows into the first media flow path S1 then flows into each upstream heat transfer tube 53 via each first outlet 52B.

[0073] As described above, the second media channel S2 has a smaller cross-sectional area compared to the first media channel S1, and the pressure loss of the working medium flowing inside is greater, making it easier to increase the flow velocity of the working medium flowing inside. For this reason, the ratio of liquid working medium to gaseous working medium is easily made uniform throughout the longitudinal direction of the second media channel S2 (i.e., the first direction D1) due to inertial force. In particular, in this embodiment, the first header 52 and the distribution mechanism 59 are aligned with the horizontal first direction D1, so the second media channel S2 is also formed along the first direction D1. For this reason, the effect of gravity on the working medium in the second media channel S2 is suppressed, and the separation of gaseous working medium and liquid working medium can be suppressed.

[0074] Furthermore, each second outlet 59B is formed at equal intervals with respect to the distribution mechanism 59, covering substantially the entire longitudinal direction of the first header 52. Moreover, since the opening area of ​​each second outlet 59B is smaller than the cross-sectional area of ​​the second media flow path S2 in a cross section perpendicular to the first direction D1, it is possible to suppress the working medium from flowing unevenly to the second outlet 59B near the second inlet 59A among the multiple second outlets 59B. As a result, the working medium, which has been homogenized in the second media flow path S2, flows substantially uniformly into substantially the entire longitudinal direction of the first media flow path S1.

[0075] Furthermore, in this embodiment, each second outlet 59B opens toward the first outlet 52B and one end of the upstream heat transfer tube 53 when viewed along the first direction D1. In addition, each second outlet 59B is formed in a position that overlaps with each first outlet 52B and each upstream heat transfer tube 53 when viewed along the third direction D3 to which the upstream heat transfer tube 53 extends. As a result, the working medium, which has been homogenized in the second medium flow path S2, flows into the first medium flow path S1 and then flows into each upstream heat transfer tube 53 in a substantially uniform manner while maintaining the ratio of liquid working medium to gaseous working medium.

[0076] The low-temperature, two-phase gas-liquid working fluid that flows into each upstream heat transfer tube 53 absorbs heat from the air transported to the user-side blower 37 via the upstream heat transfer tubes 53 and fins 54, and flows into the intermediate header 55. As described above, since the working fluid flowing into each upstream heat transfer tube 53 is made uniform, heat exchange between the working fluid and the air is easily made more efficient.

[0077] The working fluid that flows into the intermediate header 55 flows into each downstream heat transfer tube 56 connected to the intermediate header 55. The working fluid that flows into the downstream heat transfer tubes 56 absorbs heat from the air transported by the user-side blower 37 via the downstream heat transfer tubes 56 and fins 54. During cooling operation of the air conditioning system 1, the flow of the working fluid in each heat transfer tube 53, 56 and the flow of air are in opposition to each other in the user-side heat exchanger 50U, thus improving the efficiency of heat exchange. The indoor unit 3 cools the room by transporting the air that has released heat into the working fluid flowing through each heat transfer tube 53, 56 to the room.

[0078] The working fluid that has flowed through the downstream heat transfer tube 56 enters the third media flow path S3 of the second header 57 in a gaseous state. The gaseous working fluid that has entered the second header 57 enters the outlet pipe 58. As described above, the third media flow path S3 has a larger cross-sectional area compared to the media flow paths S1 and S2 of the first header 52, and the pressure loss of the working fluid flowing inside it can be reduced, making it easier to reduce the workload of the compressor 21.

[0079] The gaseous working medium that flows into the outlet pipe 58 of the user-side heat exchanger 50U is then drawn back into the compressor 21 via the user-side gas pipe 36, the internal / external connecting gas pipe 4, the first gas pipe 23, the switching section 22, and the suction pipe 21A.

[0080] [1-2-2. Operation during heating operation] The air conditioning system 1 performs heating operation by having the heat source side heat exchanger 50S function as an evaporator and the user side heat exchanger 50U function as a condenser. The operation of the air conditioning system 1 when performing heating operation will be described below.

[0081] During heating operation of the air conditioning system 1, the control unit 70 switches the flow path of the switching unit 22, connecting the discharge pipe 21B and the first gas pipe 23, and connecting the suction pipe 21A and the second gas pipe 24, as shown by the solid line in Figure 1. As a result, the high-temperature, high-pressure gaseous working medium discharged by the compressor 21 flows sequentially through the discharge pipe 21B, the switching unit 22, the first gas pipe 23, the internal / external connecting gas pipe 4, and the utilization-side gas pipe 36, before flowing into the utilization-side rectification unit 33.

[0082] Furthermore, during heating operation, the control unit 70 switches the flow path of the user-side rectifier 33, connecting the user-side gas pipe 36 with the first user-side piping 34, and connecting the second user-side piping 35 with the user-side liquid pipe 31. As a result, the working fluid that flows from the user-side gas pipe 36 into the user-side rectifier 33 flows into the first user-side piping 34. In this way, the control unit 70 uses the user-side rectifier 33 to allow the working fluid to flow into the user-side heat exchanger 50U via the first user-side piping 34 during both cooling and heating operations.

[0083] Furthermore, during heating operation of the air conditioning system 1, the control unit 70 switches the user-side switching valve 34C to the open state. As a result, the working medium in a high-temperature, high-pressure gaseous state flowing through the first user-side piping 34 flows mainly into the first inlet pipe 51A of the user-side heat exchanger 50U via the first user-side branch section 34A.

[0084] During heating operation, the working fluid that flows into the user-side heat exchanger 50U flows through the user-side heat exchanger 50U in the same manner as the heat source-side heat exchanger 50S during cooling operation. This reduces the pressure loss of the working fluid and makes it easier to reduce the workload of the compressor 21. In addition, since the flow of the working fluid in each heat transfer tube 53, 56 and the flow of air transported by the user-side blower 37 are in opposition to each other, heat exchange between the working fluid and air can be made more efficient.

[0085] The working fluid that has flowed through the user-side heat exchanger 50U becomes liquid and flows into the second user-side piping 35 via the outlet pipe 58. The working fluid in the second user-side piping 35 flows into the user-side liquid pipe 31 via the user-side rectifier 33 and reaches the expansion valve 32. The liquid working fluid flowing through the user-side liquid pipe 31 is depressurized by the expansion valve 32 and becomes a low-temperature gas-liquid two-phase state, which flows into the heat source side rectifier 25 via the internal / external connecting liquid pipe 5 and the heat source side liquid pipe 28.

[0086] During heating operation, the control unit 70 switches the flow path of the heat source side rectifier 25, connecting the heat source side liquid pipe 28 with the first heat source side piping 26, and connecting the second heat source side piping 27 with the second gas pipe 24. As a result, the working fluid that flows from the heat source side liquid pipe 28 into the heat source side rectifier 25 flows into the first heat source side piping 26. In this way, the control unit 70 uses the heat source side rectifier 25 to cause the working fluid to flow into the heat source side heat exchanger 50S via the first heat source side piping 26 during both cooling and heating operations.

[0087] Furthermore, during heating operation of the air conditioning system 1, the control unit 70 switches the heat source side switching valve 26C to the closed state. As a result, the low-temperature gas-liquid two-phase working fluid flowing through the first heat source side piping 26 flows into the second inlet pipe 51B of the heat source side heat exchanger 50S via the second heat source side branch section 26B.

[0088] During heating operation, the working fluid that flows into the heat source side heat exchanger 50S flows through the heat source side heat exchanger 50S in the same manner as the heat exchanger on the user side 50U during cooling operation. As a result, the working fluid distributed to each upstream heat transfer tube 53 is easily made uniform, and heat exchange between the working fluid and air is made more efficient. In addition, since the flow of the working fluid in each heat transfer tube 53, 56 and the flow of air transported by the heat source side blower 29 are in opposition to each other, heat exchange between the working fluid and air can be made more efficient.

[0089] The working fluid that has flowed through the heat source side heat exchanger 50S becomes a gas and flows into the second heat source side piping 27 via the outlet pipe 58. The working fluid in the second heat source side piping 27 is then drawn back into the compressor 21 via the heat source side rectifier 25, the second gas pipe 24, the switching section 22, and the suction pipe 21A.

[0090] [1-3. Effects, etc.] As described above, in this embodiment, the air conditioner 1 comprises a compressor 21, a switching unit 22 that switches between cooling operation and heating operation by switching the flow path of the working medium, a heat source side heat exchanger 50S, an expansion valve 32, and a utilization side heat exchanger 50U. The heat source side heat exchanger 50S and the utilization side heat exchanger 50U are provided with a heat source side straightening unit 25 and a utilization side straightening unit 33 that align the direction of the flow of the working medium between cooling operation and heating operation, and make the working medium and air flow in opposite directions. At least one of the heat source side heat exchanger 50S and the utilization side heat exchanger 50U comprises a plurality of upstream heat transfer tubes 53 and a first header 52 connected to the upstream side of the plurality of upstream heat transfer tubes 53 in the flow of the working medium. The first header 52 has an internal distribution mechanism 59 that equalizes the working medium distributed to the plurality of upstream heat transfer tubes 53. As a result, even if the operating mode is switched and the state of the working fluid flowing through the heat exchangers 50S and 50U, which are equipped with the first header 52, among the user-side heat exchanger 50U and the heat source-side heat exchanger 50S, changes, the working fluid distributed to each upstream heat transfer tube 53 in the heat exchangers 50S and 50U can be made uniform. Therefore, the heat exchange between the working fluid and air can be made more efficient, and the performance of the air conditioning system 1 can be easily improved.

[0091] As in this embodiment, the air conditioning system 1 may be configured such that the first header 52 is provided on both the heat source side heat exchanger 50S and the utilization side heat exchanger 50U. This makes it possible to equalize the working fluid distributed to each upstream heat transfer tube 53 in both the user-side heat exchanger 50U and the heat source-side heat exchanger 50S. As a result, heat exchange between the working fluid and air can be made more efficient, and the performance of the air conditioning system 1 can be easily improved.

[0092] As in this embodiment, in the air conditioning system 1, at least one of the heat source side heat exchanger 50S and the utilization side heat exchanger 50U, which has a first header 52, may be configured such that it is provided with a hollow second header 57 located downstream of a plurality of upstream heat transfer tubes 53 in the flow of the working medium, and the pressure loss of the working medium in the third medium flow path S3 inside the second header 57 is less than or equal to the pressure loss of the working medium in each of the plurality of medium flow paths S1 and S2 formed by partitioning the inside of the first header 52 by a distribution mechanism 59. This reduces the pressure loss in the second header 57, which is located downstream of the multiple upstream heat transfer tubes 53 in the flow of the working fluid and does not require consideration of uniformity in the distribution of the working fluid to each upstream heat transfer tube 53. As a result, the workload of the compressor 21 can be reduced, making it easier to improve the performance of the air conditioning system 1.

[0093] As in this embodiment, the first header 52 in the air conditioning system 1 may be configured to extend along a horizontal direction. This suppresses the influence of gravity on the distribution of the working fluid from the first header 52 to each upstream heat transfer tube 53. As a result, heat exchange between the working fluid and air can be made more efficient, making it easier to improve the performance of the air conditioning system 1.

[0094] As in this embodiment, the air conditioning system 1 may be configured such that the working medium is a non-azeotropic refrigerant mixture. This allows the working fluid distributed to each upstream heat transfer tube 53 to be made uniform, while simultaneously enabling heat exchange between the working fluid flow, which has a temperature glide, and the airflow in a counter-flow configuration. As a result, heat exchange between the working fluid and air can be made more efficient, making it easier to improve the performance of the air conditioning system 1.

[0095] Furthermore, in this embodiment, the heat exchangers 50, 50S, and 50U include a plurality of upstream heat transfer tubes 53, a first header 52 connected to one end of the plurality of upstream heat transfer tubes 53 and distributing the working medium to the plurality of upstream heat transfer tubes 53, and at least one distribution mechanism 59 that partitions the inside of the first header 52 and forms a plurality of medium flow paths S1 and S2 with different pressure losses from each other, and each medium flow path S1 and S2 has an inlet 52A and 59A and an outlet 52B and 59B. The first header 52 is connected to switching valves 26C and 34C that switch the flow of the working medium to the respective inlets 52A and 59A. The multiple medium flow paths S1 and S2 include a first medium flow path S1 and at least one second medium flow path S2. An upstream heat transfer tube 53 is connected to the first outlet 52B, which is the outlet of the first medium flow path S1. The second outlets 59B, which are the outlets of each second medium flow path S2, connect the second medium flow path S2 and the first medium flow path S1. This allows the switching valves 26C and 34C to switch the inflow destination of the working medium between multiple media flow paths S1 and S2 with different pressure losses, distributing the working medium to the media flow path S1 and S2 suitable for distribution according to its type or state, and distributing multiple types or states of working medium through a single first header 52. As a result, it is possible to reduce the volume and manufacturing cost of the heat exchangers 50, 50S, and 50U while suppressing performance degradation of the heat exchangers 50, 50S, and 50U by ensuring sufficient distribution performance and suppressing the increase in pressure loss.

[0096] As in this embodiment, in the heat exchangers 50, 50S, and 50U, inlet pipes 51A and 51B are connected to the respective media flow paths S1 and S2 via inlets 52A and 59A, respectively, and the inlet pipes 51A and 51B may be configured such that the inner diameter is larger the smaller the pressure loss in the connected media flow paths S1 and S2. This allows the working medium to flow through inlet pipes 51A and 51B, which have inner diameters corresponding to the pressure loss in the medium flow paths S1 and S2, thereby suppressing pressure loss in the inlet pipes 51A and 51B. As a result, performance degradation of the heat exchangers 50, 50S, and 50U can be suppressed.

[0097] As in this embodiment, in the heat exchangers 50, 50S, and 50U, the second media channel S2 may be partitioned inside the first media channel S1 and configured to have a greater pressure loss than the first media channel S1. This allows the second media channel S2, which has a small internal volume and high pressure loss, to be placed inside the first media channel S1, which has a large internal volume and low pressure loss. As a result, the structure of the first header 52 of the heat exchangers 50, 50S, and 50U can be simplified.

[0098] As in this embodiment, the first header 52 may be configured to have an elongated cylindrical shape. This allows multiple upstream heat transfer tubes 53 to be connected to the elongated cylindrical first header 52 to form heat exchangers 50, 50S, and 50U. Therefore, the structure of heat exchangers 50, 50S, and 50U can be simplified.

[0099] As in this embodiment, the upstream heat transfer tube 53 may be configured to have a flattened tube shape. This makes it easier to improve the efficiency of heat exchange between the working fluid and air via the upstream heat transfer tube 53. As a result, performance degradation of the heat exchangers 50, 50S, and 50U can be suppressed.

[0100] As in this embodiment, the first header 52 may be provided in a orientation that aligns with the first direction D1, which has a horizontal longitudinal direction, and the plurality of upstream heat transfer tubes 53 may be provided in a configuration that is arranged in line along the first direction D1. This suppresses the influence of gravity on the distribution of the working fluid from the first header 52 to each upstream heat transfer tube 53. As a result, heat exchange between the working fluid and air can be made more efficient, and performance degradation of the heat exchangers 50, 50S, and 50U can be suppressed.

[0101] As in this embodiment, the heat exchangers 50, 50S, and 50U are provided in the air conditioning system 1, and the air conditioning system 1 may be configured to include flow straightening sections 25 and 33 that, in both cases when the heat exchangers 50, 50S, and 50U function as condensers and when the heat exchangers 50, 50S, and 50U function as evaporators, direct the flow of the working fluid within the heat exchangers 50, 50S, and 50U so that the first header 52 is upstream of the flow of the working fluid relative to the plurality of upstream heat transfer tubes 53. This allows the working fluid to be distributed to multiple upstream heat transfer tubes 53 using the first header 52, both when the heat exchangers 50, 50S, and 50U function as evaporators and when they function as condensers. As a result, heat exchange between the working fluid and air can be made more efficient, and performance degradation of the heat exchangers 50, 50S, and 50U can be suppressed.

[0102] As in this embodiment, the air conditioning system 1 may be configured such that a non-azeotropic mixed refrigerant is used as the working fluid, and the heat exchangers 50, 50S, and 50U are arranged in a manner in which the internal working fluid and air flow in opposite directions, both when they function as condensers and when they function as evaporators. This allows for efficient heat exchange between the working medium, which has a temperature glide, and the air, both when the heat exchangers 50, 50S, and 50U function as evaporators and when they function as condensers. As a result, performance degradation of the heat exchangers 50, 50S, and 50U can be suppressed.

[0103] As in this embodiment, in the heat exchangers 50, 50S, and 50U, the switching valves 26C and 34C may be connected to the first inlet 52A, which is the inlet of the first medium flow path S1. This allows the working fluid to flow through the second fluid passage S2 by closing the switching valves 26C and 34C, and through the first fluid passage S1, which has a lower pressure loss than the second fluid passage S2, by opening the switching valves 26C and 34C. As a result, the number of switching valves 26C and 34C can be reduced, thereby lowering manufacturing costs.

[0104] (Embodiment 2) The following describes the heat exchanger 150 according to Embodiment 2. Note that the following will describe the differences from Embodiment 1, and explanations of matters similar to those in Embodiment 1 may be omitted.

[0105] [2-1. Structure] Figure 5 is a perspective view of the heat exchanger 150 according to Embodiment 2. Figure 6 is a cross-sectional view of VI in Figure 5, showing the cross-section of the first header 152 in a cross-section perpendicular to the third direction D3. The heat exchanger 150 according to Embodiment 2 can be used as either a heat source side heat exchanger 50S or a utilization side heat exchanger 50U.

[0106] The heat exchanger 150 of Embodiment 2 has inlet pipes 51, 51A, and 51B similar to those of Embodiment 1. Each inlet pipe 51, 51A, and 51B extends outward from the first header 152 according to Embodiment 2.

[0107] As shown in Figures 5 and 6, the first header 152 is an elongated cylindrical member that extends linearly along the first direction D1. In Embodiment 2, a partition 152A is provided inside the first header 152. The partition 152A is a plate-like structure that divides the space inside the first header 152 into one side and the other side in the first direction D1. Hereinafter, one side of the partition 152A of the first header 152 will be referred to as the flow separation section 152B, and the other side of the partition 152A will be referred to as the confluence section 152C.

[0108] As shown in Figures 5 and 6, the flow divider 152B has a structure similar to the first header 52 in Embodiment 1. More specifically, similar to Embodiment 1, the flow divider 152B has a first inlet 52A and a plurality of first outlets 52B. Also similar to Embodiment 1, a first inlet pipe 51A is connected to the first inlet 52A, and one end of the upstream heat transfer tube 53 is connected to the first outlet 52B. Furthermore, similar to Embodiment 1, a distribution mechanism 59 is provided inside the flow divider 152B, which has a second inlet 59A and a plurality of second outlets 59B, and a second inlet pipe 51B is connected to the second inlet 59A. A first medium flow path S1 similar to Embodiment 1 is formed between the inner surface of the flow divider 152B and the outer surface of the distribution mechanism 59, and is in communication with a second medium flow path S2 inside the distribution mechanism 59 via the second outlets 59B.

[0109] In other words, in Embodiment 2, the flow diversion section 152B, which is a part of the total length of the first header 152, functions as a flow diverter that distributes the working fluid to each upstream heat transfer tube 53. The flow divider 152B corresponds to an example of a “flow divider” in this disclosure. The first header 152 corresponds to an example of a “header flow divider” in this disclosure.

[0110] As shown in Figure 5, in Embodiment 2, the other end of each upstream heat transfer tube 53 is connected to a folded header 155. The folded header 155 is a hollow cylindrical member extending along the first direction D1, with both ends closed. The folded header 155 is provided in the same area as the first header 152 in the first direction D1.

[0111] On the other side of the folded header 155 in the first direction D1 from the portion connected to the plurality of upstream heat transfer tubes 53, a plurality of downstream heat transfer tubes 56 similar to those in Embodiment 1 are provided. The other end of each downstream heat transfer tube 56 is connected to the aforementioned junction 152C.

[0112] A third medium flow path S3, similar to that in Embodiment 1, is formed inside the confluence section 152C. Furthermore, an outlet pipe 58, similar to that in Embodiment 1, is connected to the confluence section 152C and communicates with the third medium flow path S3.

[0113] [2-2. Operation] The flow of the working fluid in the heat exchanger 150 configured as described above will be explained below.

[0114] When the working fluid flows into the heat exchanger 150, it flows into the inside of the diversion section 152B via the first inlet pipe 51A or the second inlet pipe 51B. The working fluid that has flowed into the inside of the diversion section 152B is distributed to each upstream heat transfer tube 53. The working fluid distributed to each upstream heat transfer tube 53 then flows out of the heat exchanger 150 in order via the return header 155, each downstream heat transfer tube 56, the third fluid flow path S3 of the confluence section 152C, and the outlet pipe 58.

[0115] As described above, the flow divider 152B has the same structure as the first header 52 in Embodiment 1 and functions as a flow divider. Therefore, when the heat exchanger 150 functions as an evaporator, the working medium in a gas-liquid two-phase state is introduced into the second medium flow path S2 via the second inlet 52B, making it easier to homogenize the working medium distributed to each upstream heat transfer tube 53. Also, when the heat exchanger 150 functions as a condenser, the working medium in a gaseous state is introduced into the first medium flow path S1 via the first inlet 52A, making it possible to reduce the pressure loss of the working medium.

[0116] [2-3. Effects, etc.] As in this embodiment, the heat exchanger 150 may be configured to include a first header 152, and the flow distribution section 152B may be provided in a portion of the total length of the first header 152. This allows the first header 152 to have a function that distributes the working medium to only a portion of it, while the other portion is assigned a different function. This increases the design flexibility of the heat exchanger 150.

[0117] (Other embodiments) As described above, Embodiments 1 and 2 have been presented as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited thereto and can be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, it is possible to combine the components described in Embodiments 1 and 2 to create new embodiments. Therefore, other embodiments are illustrated below.

[0118] In Embodiment 1, it was explained that both the heat source side heat exchanger 50S and the utilization side heat exchanger 50U have a first header 52 with a distribution mechanism 59 inside, but this is just one example. The first header 52 only needs to be provided in at least one of the heat source side heat exchanger 50S and the utilization side heat exchanger 50U. For example, the first header 52 may be provided only in the heat source side heat exchanger 50S and the utilization side heat exchanger 50U, which has a larger height (vertical) dimension, as the influence of gravity on the distribution of the working medium tends to be greater in that latter.

[0119] In other words, as in other embodiments, the air conditioning system 1 may be configured such that the first header 52 is provided on the side of the heat source side heat exchanger 50S and the utilization side heat exchanger 50U that has a larger height dimension. This makes it possible to equalize the distribution of the working fluid to each upstream heat transfer tube 53 in a heat exchanger 50, which has a large height dimension and in which the working fluid is particularly susceptible to the effects of gravity. As a result, the heat exchange between the working fluid and air can be made more efficient, and the performance of the air conditioning system 1 can be easily improved.

[0120] In the above embodiment, it was explained that the first direction D1, to which the first headers 52, 152, intermediate header 55, second header 57, and folded header 155 extend, is a horizontal direction, but this is just one example. For example, the first direction D1 may be a direction along the vertical direction, and the first headers 52, 152, intermediate header 55, second header 57, and folded header 155 may extend along the vertical direction. Also, the second direction D2 to which each heat transfer tube 53, 56 extends is not limited to the vertical direction, but may be a horizontal direction or the like.

[0121] In the above embodiment, it was explained that one distribution mechanism 59 is provided inside the first header 52 and the flow divider 152B, but this is just one example. The number of distribution mechanisms 59 provided inside the first header 52 and the flow divider 152B may be multiple. In this case, the cross-sectional areas of each distribution mechanism 59 and each second medium flow path S2 inside it in a cross section perpendicular to the first direction D1 may be different from each other, and the magnitude of the pressure loss generated in the working medium flowing inside may also be different from each other. In this case, each second inlet 59A of each distribution mechanism 59 may be connected to a second inlet pipe 51B with a different inner diameter.

[0122] In the above embodiment, a four-way valve was described as an example of the switching unit 22, the heat source side rectifier unit 25, and the user side rectifier unit 33, but this is just one example. The switching unit 22 only needs to be capable of switching the operating mode of the air conditioner 1 between cooling operation and heating operation. In addition, each rectifier unit 25 and 33 only needs to be capable of aligning the direction of the flow of the working fluid in each heat exchanger 50S and 50U between cooling operation and heating operation, and making the working fluid and air flow in opposite directions. For this reason, the switching unit 22, the heat source side rectifier unit 25, and the user side rectifier unit 33 may each be composed of any combination of valves such as on-off valves or check valves.

[0123] In the above embodiment, the air conditioning system 1 was described as an example of a refrigeration cycle device, but this is merely an example. A refrigeration cycle device can be any device that uses a working fluid in a refrigeration cycle to cause one of the heat exchangers, the user-side heat exchanger and the heat source-side heat exchanger, to function as a condenser, and the other to function as an evaporator. For this reason, the refrigeration cycle device can be any type of refrigeration device, such as a refrigerator, freezer, display case, or ice maker.

[0124] Furthermore, in the above embodiment, cooling operation was described as an example of cooling operation, and heating operation was described as an example of heating operation, but this is merely an example. Cooling operation is any operation in which the user-side heat exchanger functions as an evaporator, the heat source-side heat exchanger functions as a condenser, and the user-side heat exchanger cools the space or object. Heating operation is any operation in which the user-side heat exchanger functions as a condenser, the heat source-side heat exchanger functions as an evaporator, and the user-side heat exchanger heats the space or object. For example, if the refrigeration cycle device is a refrigerator, freezer, display case, or ice maker, cooling operation may be, for example, an operation to cool the space or water inside the container, and heating operation may be, for example, an operation to defrost the user-side heat exchanger.

[0125] In the above embodiment, the control unit 70 was described as including a processor and a storage medium, but this is just one example. The control unit 70 may, for example, use wired logic that cannot be rewritten. Using wired logic in the control unit 70 is effective in improving processing speed. Examples of wired logic include ASICs (Application Specific Integrated Circuits). Alternatively, the control unit 70 may be implemented by combining a processor and wired logic. Implementing the control unit 70 by combining a processor and wired logic can improve processing speed while increasing the degree of freedom in software design. Furthermore, the control unit 70 and a circuit having a different function from the control unit 70 may be configured with a single semiconductor element. Examples of circuits having a different function include A / D-D / A conversion circuits. The control unit 70 may also be configured with a single semiconductor element or with multiple semiconductor elements. When configured with multiple semiconductor elements, various controls may be implemented with different semiconductor elements. Moreover, the control unit 70 may be configured with a configuration including semiconductor elements and passive components such as resistors or capacitors.

[0126] Since the embodiments described above are for illustrative purposes of the technology described herein, various modifications, substitutions, additions, omissions, etc., can be made within the claims or their equivalents.

[0127] (Note) Based on the above description of embodiments, the following technologies are disclosed. (Technical 1) A refrigeration cycle device comprising a compressor, a switching unit for switching between cooling operation and heating operation by switching the flow path of a working medium, a heat source side heat exchanger, an expansion valve, and a utilization side heat exchanger, wherein the heat source side heat exchanger and the utilization side heat exchanger are provided with a flow straightening unit that aligns the direction of the flow of the working medium between the cooling operation and the heating operation and causes the working medium and air to flow in opposite directions, and at least one of the heat source side heat exchanger and the utilization side heat exchanger comprises a plurality of heat transfer tubes and a first header connected to the upstream side of the plurality of heat transfer tubes in the flow of the working medium, wherein the first header has an internal distribution mechanism for homogenizing the working medium distributed to the plurality of heat transfer tubes. As a result, even when the operating mode is switched and the state of the working fluid flowing through the heat exchanger equipped with the first header (between the user-side heat exchanger and the heat source-side heat exchanger) changes, the working fluid distributed to each heat transfer tube in that heat exchanger can be made uniform. Therefore, the heat exchange between the working fluid and air can be made more efficient, and the performance of the refrigeration cycle system can be easily improved.

[0128] (Technical 2) The refrigeration cycle apparatus according to Technical 1, wherein the first header is provided on the heat source side heat exchanger and the utilization side heat exchanger, whichever has the larger height dimension. This makes it possible to equalize the distribution of the working fluid to each heat transfer tube, especially in heat exchangers with large height dimensions where the working fluid is particularly susceptible to the effects of gravity. As a result, heat exchange between the working fluid and air can be made more efficient, making it easier to improve the performance of the refrigeration cycle system.

[0129] (Technical 3) The refrigeration cycle apparatus according to Technical 1, wherein the first header is provided in both the heat source side heat exchanger and the utilization side heat exchanger. This allows for the uniform distribution of the working fluid to each heat transfer tube in both the user-side heat exchanger and the heat source-side heat exchanger. As a result, heat exchange between the working fluid and air can be made more efficient, making it easier to improve the performance of the refrigeration cycle system.

[0130] (Technical 4) The refrigeration cycle apparatus according to any one of Technical 1 to 3, wherein at least one of the heat source side heat exchanger and the utilization side heat exchanger having the first header is provided with a hollow second header located downstream of the plurality of heat transfer tubes in the flow of the working medium, and the pressure loss of the working medium inside the second header is less than or equal to the pressure loss of the working medium in each of the plurality of medium flow paths formed by partitioning the inside of the first header by the distribution mechanism. This reduces the pressure loss in the second header, which is located downstream of the multiple heat transfer tubes in the working fluid flow and does not require consideration of uniformity in the distribution of the working fluid to each heat transfer tube. As a result, the workload of the compressor can be reduced, making it easier to improve the performance of the refrigeration cycle system.

[0131] (Technical 5) The refrigeration cycle apparatus according to any one of Technical 1 to 4, wherein the first header extends along a horizontal direction. This reduces the influence of gravity on the distribution of the working fluid from the first header to each heat transfer tube. As a result, heat exchange between the working fluid and air can be made more efficient, making it easier to improve the performance of the refrigeration cycle system.

[0132] (Technical 6) The refrigeration cycle apparatus according to any one of Technical 1 to 5, wherein the working medium is a non-azeotropic mixed refrigerant. This allows for the uniform distribution of the working fluid to each heat transfer tube, while simultaneously enabling heat exchange between the working fluid, which has a temperature glide, and the airflow in a counter-flow configuration. As a result, heat exchange between the working fluid and air can be made more efficient, making it easier to improve the performance of the refrigeration cycle system. [Industrial applicability]

[0133] This disclosure is applicable to refrigeration cycle equipment. Specifically, this disclosure is applicable to air conditioners, refrigerators, freezers, display cases, ice makers, etc., that can switch between heating and cooling operations. [Explanation of symbols]

[0134] 1. Air conditioning system (refrigeration cycle system) 1A Refrigerant Circuit 2 Outdoor unit 3 Indoor unit 4. Internal and external gas pipes 5. Internal and external connecting liquid pipes 21 Compressor 21A Suction piping 21B Discharge piping 22 Switching section 23. First gas pipe 24 Second gas pipe 25 Heat source side rectifier (rectifier) 26 1st heat source side piping 26A First heat source side branch section 26B Second heat source side branch section 26C Heat source side switching valve (switching valve) 27 2nd heat source side piping 28 Heat source side liquid pipe 29 Heat source side blower 31 User side liquid pipe 32 Expansion valve 33 User side rectifier (rectifier) 34 1st user side piping 34A First user-side branch section 34B Second user-side branch section 34C User-side switching valve (switching valve) 35 2nd user side piping 36. Gas pipe on the user side 37. User-side blower 50 heat exchanger 50S Heat source side heat exchanger (heat exchanger) 50U User side heat exchanger (heat exchanger) 51 Inflow pipe 51A 1st inflow pipe (inflow pipe) 51B 2nd inflow pipe (inflow pipe) 52. First Header (Shrew) 52A 1st inlet (inlet) 52B 1st outlet (outlet) 53 Upstream heat transfer tube (heat transfer tube) 54 Fins 55 Intermediate Header 56 Downstream heat transfer tube 57 Second Header 58 Outflow pipe 59 Distribution mechanism 59A 2nd inlet (inlet) 59B 2nd outlet (outlet) 70 Control Unit 150 Heat exchanger 152 First Header (Header Shunt) 152A Partition 152B Diversion section (shunt) 152C Junction 155 Wrap Header S Medium flow path S1 First medium channel (medium channel) S2 Second medium flow path (medium flow path) S3 Third Medium Channel

Claims

1. It comprises a compressor, a switching unit that switches between cooling and heating operations by switching the flow path of the working medium, a heat source side heat exchanger, an expansion valve, and a utilization side heat exchanger. The heat source side heat exchanger and the utilization side heat exchanger are provided with a flow straightening section that aligns the direction of the working medium flow between the cooling operation and the heating operation, and causes the working medium and air to flow in opposite directions. At least one of the heat source side heat exchanger and the utilization side heat exchanger is Multiple heat transfer tubes, In the flow of the working fluid, a first header connected to the upstream side of the plurality of heat transfer tubes, Equipped with, The first header has an internal distribution mechanism that equalizes the working medium distributed to the plurality of heat transfer tubes. Refrigeration cycle device.

2. The first header is provided on the heat source side heat exchanger and the utilization side heat exchanger, whichever has the larger height dimension. The refrigeration cycle apparatus according to claim 1.

3. The first header is provided in both the heat source side heat exchanger and the utilization side heat exchanger. The refrigeration cycle apparatus according to claim 1.

4. Of the heat source side heat exchanger and the utilization side heat exchanger, at least one having the first header is provided with a hollow second header located downstream of the plurality of heat transfer tubes in the flow of the working medium. The pressure loss of the working medium inside the second header is less than or equal to the pressure loss of the working medium in each of the multiple medium flow paths formed by partitioning the inside of the first header by the distribution mechanism. The refrigeration cycle apparatus according to claim 1.

5. The first header extends along the horizontal direction, The refrigeration cycle apparatus according to claim 1.

6. The working fluid is a non-azeotropic refrigerant mixture. A refrigeration cycle apparatus according to any one of claims 1 to 5.

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