Outdoor unit and air conditioning device

Abstract

This outdoor unit comprises a housing, a plurality of heat exchangers, at least one fan, an internal component that causes ventilation resistance, and a pipe part that is branched and connected to the plurality of heat exchangers, wherein: the plurality of heat exchangers are disposed on at least two side surfaces; the plurality of heat exchangers are each connected to the pipe part so that refrigerant flows are in parallel with each other; the plurality of heat exchangers and / or the pipe part include(s) a flow rate adjustment mechanism that adjusts the flow rate of a refrigerant which flows into a plurality of heat transfer pipes; and the plurality of heat exchangers are configured such that when a heat exchanger which is closest to the internal component is defined as a first heat exchanger and all the other heat exchangers are defined as second heat exchangers, the flow rate of a refrigerant flowing to the first heat exchanger in each one of the plurality of heat transfer pipes is made smaller, by the flow rate adjustment mechanism, than the flow rate of a refrigerant flowing to the second heat exchanger in each one of the plurality of heat transfer pipes.

Description

Outdoor units and air conditioning equipment

[0001] The present disclosure relates to a top-flow type outdoor unit that constitutes an air conditioner, and to the air conditioner.

[0002] Conventionally, a top-flow outdoor unit has been proposed that aims to suppress a decrease in heat exchange rate due to uneven wind speed distribution of air passing through the heat exchanger (see, for example, Patent Document 1). The outdoor unit of Patent Document 1 has a heat exchanger including an inlet header, an outlet header, multiple chambers separated by partitions inside the inlet header, multiple flat tubes arranged in parallel and connected to each chamber and the outlet header, a distributor provided in the refrigerant piping, and multiple branch pipes connected to each chamber and the distributor. In the heat exchanger of Patent Document 1, the branch pipes are provided with branch sections between the chambers and the distributor in accordance with the wind speed distribution, and the number of branch sections of the branch pipes connected to rooms connected to flat tubes located in areas with high wind speeds is configured to be fewer than the number of branch sections of the branch pipes connected to rooms connected to flat tubes passing through areas with low wind speeds.

[0003] International Publication No. 2022 / 209919

[0004] The outdoor unit of Patent Document 1 includes a heat exchanger with horizontally extending heat transfer tubes, achieving refrigerant distribution suited to the vertical air velocity distribution around the housing. When a top-flow air conditioner with vertically extending heat transfer tubes is installed in an outdoor unit, the outdoor unit must achieve refrigerant distribution suited to the air velocity distribution in the direction in which the heat transfer tubes are arranged, i.e., the circumferential direction of the housing, rather than the vertical air velocity distribution. In particular, heat exchangers located near components with large occupancies, such as compressors or accumulators, experience increased ventilation resistance, reducing the amount of air passing through the heat exchanger, resulting in uneven air velocity distribution and potentially degrading heat exchange performance. The outdoor unit of Patent Document 1 does not consider the possibility of uneven air velocity distribution around the housing resulting in uneven air velocity passing through multiple heat exchangers. Therefore, in the outdoor unit of Patent Document 1, the uneven distribution of wind speed around the circumferential direction of the housing can cause uneven heat exchange amounts in the multiple outdoor heat exchangers, which can result in a decrease in the heat exchange performance of the multiple heat exchangers as a whole.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an outdoor unit and an air conditioning apparatus that improve the heat exchange performance of multiple heat exchangers as a whole, even when there is a bias in the wind speed distribution around the circumferential direction of the housing.

[0006] The outdoor unit according to the present disclosure is an outdoor unit for an air conditioner, and comprises: a rectangular box-shaped housing with an air outlet formed on its top surface; a plurality of heat exchangers arranged inside the housing and having a plurality of heat transfer tubes extending in the vertical direction, for exchanging heat between a refrigerant and air; at least one fan arranged on the top of the housing for blowing air taken in from the side of the housing upward through the plurality of heat exchangers after passing the air through the plurality of heat exchangers; an internal component of the outdoor unit installed on the bottom of the housing, the internal component being arranged on an air path from any one of the plurality of heat exchangers to the fan and generating ventilation resistance; and a piping section through which a refrigerant flows, the piping section being provided upstream of the plurality of heat exchangers in the refrigerant flow direction and branching and connected to the plurality of heat exchangers, and the plurality of The heat exchangers are arranged on at least two of the four side surfaces of the housing, and each of the multiple heat exchangers is connected to a piping section so that the flows of refrigerant passing through the multiple heat exchangers are parallel to each other, and at least one of the multiple heat exchangers or the piping section includes a flow rate adjustment mechanism that adjusts the flow rate of refrigerant flowing into the multiple heat transfer tubes, and the multiple heat exchangers are configured such that, when the heat exchanger among the multiple heat exchangers that is closest to the internal parts is designated as the first heat exchanger and all of the other heat exchangers other than the first heat exchanger are designated as the second heat exchangers, the flow rate adjustment mechanism makes the refrigerant flow rate per each of the multiple heat transfer tubes flowing into the first heat exchanger smaller than the refrigerant flow rate per each of the multiple heat transfer tubes flowing into the second heat exchanger.

[0007] The air conditioning apparatus according to the present disclosure comprises an outdoor unit having the above-described configuration, and an indoor unit connected to the outdoor unit by piping through which a refrigerant flows, having an indoor heat exchanger, and performing heat exchange between the indoor air and the refrigerant flowing therethrough.

[0008] The present disclosure provides an outdoor unit and an air conditioner that improve the overall heat exchange performance of a plurality of heat exchangers even when the wind speed distribution in the circumferential direction of the housing is uneven as described above.

[0009] 1. A refrigerant circuit diagram showing an example of the basic configuration of an air conditioning apparatus according to Embodiment 1.

[0023] FIG. 1 is a front perspective view of an outdoor unit of an air conditioning apparatus according to Embodiment 1.

[0024] FIG. 2 is a rear perspective view of an outdoor unit of an air conditioning apparatus according to Embodiment 1.

[0025] FIG. 3 is an exploded front perspective view of an outdoor unit of an air conditioning apparatus according to Embodiment 1.

[0026] FIG. 4 is an exploded side perspective view of an outdoor unit of an air conditioning apparatus according to Embodiment 1.

[0027] FIG. 5 is a plan view of the internal configuration of an outdoor unit of an air conditioning apparatus according to Embodiment 1.

[0028] FIG. 6 is a schematic perspective view of a heat exchanger of an air conditioning apparatus according to Embodiment 1.

[0029] FIG. 7 is a conceptual diagram showing the configuration of a distribution header of a heat exchanger according to Embodiment 1.

[0030] FIG. 8 is a refrigerant circuit diagram showing an example of a flow rate adjustment mechanism of an air conditioning apparatus according to Embodiment 1.

[0031] FIG. 9 is a conceptual diagram showing an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioning apparatus according to Embodiment 1.

[0032] FIG. 10 is a conceptual diagram for explaining examples of the flow rate adjustment mechanisms of FIGS. 9 and 10.

[0033] FIG. 11 is a refrigerant circuit diagram of a first modified example of an air conditioning apparatus according to Embodiment 1.

[0034] FIG. 12 is a refrigerant circuit diagram of a second modified example of an air conditioning apparatus according to Embodiment 1.

[0035] FIG. 13 is a refrigerant circuit diagram of a third modified example of an air conditioning apparatus according to Embodiment 1. 10 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 2. FIG. 11 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 3. FIG. 12 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 4. FIG. 13 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 5. FIG. 14 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 6. FIG. 15 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 7. FIG. 16 is a conceptual diagram for illustrating an example of a flow rate adjustment mechanism in an outdoor unit of an air conditioner according to Embodiment 8. FIG. 17 is a conceptual diagram showing an example of an outdoor unit of an air conditioner according to Embodiment 8.

[0010] An outdoor unit and an air conditioning apparatus according to an embodiment will be described below with reference to the drawings. Note that in the following drawings, including FIG. 1, the relative dimensional relationships and shapes of the components may differ from those in reality. In the following drawings, the same reference numerals denote the same or equivalent components, and this applies throughout the entire specification. To facilitate understanding, terms indicating directions (e.g., up, down, right, left, front, rear, etc.) are used as appropriate, but these notations are merely used for the convenience of explanation and do not limit the arrangement or orientation of the device or components.

[0011] Embodiment 1. <Configuration of Air Conditioning Apparatus 1> Fig. 1 is a refrigerant circuit diagram showing an example of the basic configuration of an air conditioning apparatus 1 according to Embodiment 1. The air conditioning apparatus 1 will be described using Fig. 1. Note that Fig. 1 shows the circuit configuration of a refrigerant circuit 100, which will be described later, and the length of the flow path of the pipes 101 that make up the refrigerant circuit 100 differs from the actual length.

[0012] An air conditioner 1 is a device that performs air conditioning by heating or cooling a room by transferring heat between outdoor air and indoor air via a refrigerant. As shown in Fig. 1 , the air conditioner 1 according to embodiment 1 includes an outdoor unit 10 and an indoor unit 20 that is connected to the outdoor unit 10 by piping 101 through which the refrigerant flows and has an indoor heat exchanger 22 for exchanging heat between the indoor air and the refrigerant flowing therethrough. Note that while Fig. 1 shows one outdoor unit 10 and one indoor unit 20, there may be a plurality of outdoor units 10 and a plurality of indoor units 20.

[0013] The air conditioner 1 is composed of an outdoor unit 10 and an indoor unit 20, and is provided with a refrigerant circuit 100 through which a refrigerant circulates. Specifically, the refrigerant circuit 100 is composed of a compressor 11, a flow path switching device 12, an indoor heat exchanger 22, a throttling device 21, a flow control valve 13, a heat exchanger 30, and an accumulator 16, which are sequentially connected by multiple pipes 101. This air conditioner 1 is capable of both cooling operation and heating operation by switching the flow path switching device 12, and is also capable of defrosting operation.

[0014] The refrigerant circuit 100 of the air conditioner 1 in Fig. 1 is an example, and the air conditioner 1 is not limited to the configuration of the refrigerant circuit 100 in Fig. 1. For example, the air conditioner 1 does not need to have the flow path switching device 12 and the accumulator 16, and the number of heat exchangers 30 may be different. The refrigerant circuit 100 of the air conditioner 1 may be configured by sequentially connecting the compressor 11, the flow path switching device 12, the indoor heat exchanger 22, the throttling device 21, the flow control valve 13, and the heat exchanger 30 via piping 101.

[0015] [Outdoor unit 10] The outdoor unit 10 includes a compressor 11, a flow path switching device 12, a plurality of heat exchangers 30, a plurality of flow control valves 13, an on-off valve 14, a check valve 15, an accumulator 16, a temperature sensor 17, and a fan 18.

[0016] The compressor 11 and the accumulator 16 are internal components 19 of the outdoor unit 10. The internal components 19 are components used in the operation of the outdoor unit 10 and the air conditioning apparatus 1. The internal components 19 are components that occupy a large volume in the internal space 45 (see FIG. 4 ) of the outdoor unit 10. Note that if the outdoor unit 10 does not have the accumulator 16, the internal component 19 is the compressor 11. The internal component 19 is composed of either or both of the compressor 11 that compresses and discharges the refrigerant and the accumulator 16 that stores liquid refrigerant inside the housing 40.

[0017] The compressor 11 draws in a low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges a high-temperature, high-pressure refrigerant. The compressor 11 is, for example, an inverter compressor whose capacity, which is the amount of refrigerant delivered per unit time, is controlled by changing the operating frequency.

[0018] The flow path switching device 12 is, for example, a four-way valve, and switches between cooling operation and heating operation by switching the direction of refrigerant flow. During cooling operation, the flow path switching device 12 switches to connect the discharge side of the compressor 11 to the heat exchanger 30. During heating operation, the flow path switching device 12 switches to connect the discharge side of the compressor 11 to the indoor heat exchanger 22. The air conditioning apparatus 1 can achieve cooling operation, heating operation, defrosting operation, or the like by switching the refrigerant flow using the flow path switching device 12 based on instructions from a control device (not shown).

[0019] The heat exchanger 30 exchanges heat between the outdoor air and the refrigerant. During cooling operation, the heat exchanger 30 functions as a condenser that radiates heat from the refrigerant to the outdoor air to condense the refrigerant. During heating operation, the heat exchanger 30 absorbs heat from the outdoor air to evaporate the refrigerant, and functions as an evaporator that cools the outdoor air with the heat of vaporization.

[0020] In the embodiment of the outdoor unit 10 in the refrigerant circuit 100 of the air conditioner 1 shown in Fig. 1, the outdoor unit 10 has three heat exchangers 30: heat exchanger 30a, heat exchanger 30b, and heat exchanger 30c. In the embodiment of the outdoor unit 10 shown in Fig. 1, the outdoor unit 10 has three heat exchangers 30, but the number of heat exchangers 30 installed in the outdoor unit 10 is not limited to three. The outdoor unit 10 may have a plurality of heat exchangers 30, and may have, for example, two heat exchangers 30 or four heat exchangers 30.

[0021] The fan 18 supplies outdoor air to the plurality of heat exchangers 30, and the amount of air blown to the heat exchangers 30 is adjusted by controlling the rotation speed.

[0022] The flow rate control valve 13 is, for example, an electronic expansion valve that can adjust the aperture, and by adjusting the aperture, the pressure of the refrigerant flowing into the heat exchanger 30 that functions as an evaporator is controlled. In the aspect of the outdoor unit 10 in the refrigerant circuit 100 of the air conditioner 1 shown in Figure 1, the outdoor unit 10 has two flow rate control valves 13, a flow rate control valve 13a and a flow rate control valve 13b.

[0023] The flow rate control valve 13a adjusts the flow rate of the refrigerant flowing into the heat exchanger 30a and the heat exchanger 30b by changing its opening degree. The flow rate control valve 13b adjusts the flow rate of the refrigerant flowing into the heat exchanger 30c by changing its opening degree.

[0024] The on-off valve 14 is a two-way valve that allows the refrigerant to flow when open and restricts the flow when closed, and is open during cooling operation and closed during heating operation. The check valve 15 prevents the refrigerant from flowing backward and restricts the refrigerant to flow in only one direction. A two-way valve may be provided instead of the check valve 15.

[0025] The accumulator 16 is provided on the intake side of the compressor 11 and serves to store excess refrigerant that occurs due to differences in operating conditions between cooling and heating, or excess refrigerant that occurs due to transient changes in operation, etc. Furthermore, the accumulator 16 serves to prevent liquid compression in the compressor 11.

[0026] The temperature sensor 17 is, for example, a thermistor, and is provided in the pipe 101a between the heat exchanger 30c and the flow control valve 13b to detect the temperature of the refrigerant flowing through the pipe 101a. As will be described later, this temperature sensor 17 is provided only in the pipe 101a on the outlet side of the heat exchanger 30c, which is downstream during cooling operation and defrost operation. The pipe 101a is one of the multiple pipes 101 that make up the refrigerant circuit 100.

[0027] [Indoor Unit 20] The indoor unit 20 includes an expansion device 21, an indoor heat exchanger 22, and an indoor fan 23.

[0028] The expansion device 21 is, for example, an electronic expansion valve that can adjust the aperture, and by adjusting the aperture, controls the pressure of the refrigerant flowing into the heat exchanger 30 or the indoor heat exchanger 22. In the first embodiment, the expansion device 21 is provided in the indoor unit 20, but it may also be provided in the outdoor unit 10, and the installation location is not limited.

[0029] The indoor heat exchanger 22 exchanges heat between the indoor air and the refrigerant. During cooling operation, the indoor heat exchanger 22 functions as an evaporator that evaporates the refrigerant and cools the indoor air with the heat of vaporization. During heating operation, the indoor heat exchanger 22 functions as a condenser that radiates heat from the refrigerant to the indoor air to condense the refrigerant.

[0030] The indoor fan 23 supplies indoor air to the indoor heat exchanger 22, and the amount of air blown to the indoor heat exchanger 22 is adjusted by controlling the rotation speed.

[0031] [Basic Configuration of Outdoor Unit 10] Fig. 2 is a perspective view of the outdoor unit 10 of the air conditioning apparatus 1 according to Embodiment 1, as seen from the front. Fig. 3 is a perspective view of the outdoor unit 10 of the air conditioning apparatus 1 according to Embodiment 1, as seen from the back. Fig. 4 is an exploded perspective view of the outdoor unit 10 of the air conditioning apparatus 1 according to Embodiment 1, as seen from the front. Fig. 5 is an exploded perspective view of the outdoor unit 10 of the air conditioning apparatus 1 according to Embodiment 1, as seen from the side. Fig. 6 is a conceptual diagram showing a plan view of the internal configuration of the outdoor unit 10 of the air conditioning apparatus 1 according to Embodiment 1. The outline arrows in Fig. 6 indicate the direction of air flow, and the solid arrows in Fig. 6 indicate the direction of refrigerant flow. The basic configuration of the outdoor unit 10 will be described using Figs. 2 to 6.

[0032] The outdoor unit 10 is an outdoor unit of the air conditioning apparatus 1. The outdoor unit 10 has a housing 40, multiple heat exchangers 30, at least one fan 18, and an internal component 19 that is arranged in an air path leading from any one of the multiple heat exchangers 30 to the fan 18 and generates ventilation resistance. The outdoor unit 10 also has a piping section 110 that branches and is connected to the multiple heat exchangers 30. The outdoor unit 10 also includes a flow rate adjustment mechanism 50 that adjusts the flow rate of refrigerant flowing into the multiple heat transfer tubes 34. As shown in FIGS. 2 to 6 , the outdoor unit 10 is a top-flow type outdoor unit that has the fan 18 located at the top center of the housing 40 that forms the outer shell.

[0033] The housing 40 forms the outer shell of the outdoor unit 10. The housing 40 may also be referred to as the outdoor unit main body. The housing 40 is formed in the shape of a rectangular parallelepiped box, and has an air outlet 41 formed on the top surface. The outlet 41 is an opening through which air blown by the fan 18, which will be described later, is discharged. As shown in Figures 2 and 3, the outlet 41 is formed in the center of the top of the housing 40, and as shown in Figures 4 and 5, the fan 18 is disposed directly below the outlet 41.

[0034] The housing 40 is formed in a rectangular box shape and has a bottom portion 40e formed in a plate shape on the bottom surface thereof. The internal components 19 of the outdoor unit 10, such as the compressor 11 and the accumulator 16, are installed on the bottom portion 40e.

[0035] The housing 40 has four side surfaces, three of which have heat exchangers 30 disposed thereon, and a sealing plate 43 for preventing air inflow on the side surface where the heat exchangers 30 are not disposed. The four side surfaces of the housing 40 are a first surface 40a, a second surface 40b, a third surface 40c, and a fourth surface 40d. The four side surfaces of the housing 40 extend upward from four edges of the bottom 40e of the housing 40. As shown in FIG. 6 , when the side surface on which the sealing plate 43 is disposed is defined as the front surface, the first surface 40a is the right side surface, the second surface 40b is the left side surface, the third surface 40c is the rear surface, and the fourth surface 40d is the front surface.

[0036] 2 and 6 , a removable sealing plate 43 is provided on the fourth surface 40d, which is the front surface of the housing 40. The sealing plate 43 is a so-called service panel, and is detachably attached to the housing 40. By removing the sealing plate 43, an operator can perform work inside the housing 40 of the outdoor unit 10, and by attaching the sealing plate 43, the inflow of air into the housing 40 at the fourth surface 40d is prevented or suppressed. Note that the outdoor unit 10 may not have the sealing plate 43, and a heat exchanger 30 may be provided instead of the sealing plate 43.

[0037] Each of the first surface 40a, the second surface 40b, and the third surface 40c of the housing 40 is a flow surface through which air flows, and has an air inlet 40f formed therein. A heat exchanger 30 is installed in each of the air inlet 40f on the first surface 40a, the second surface 40b, and the third surface 40c of the housing 40.

[0038] 4 and 6 , the housing 40 contains a plurality of heat exchangers 30, internal components 19 of the outdoor unit 10, a fan 18, and piping 110. More specifically, the housing 40 contains a plurality of heat exchangers 30, a compressor 11, an accumulator 16, a fan 18, and piping 110.

[0039] 4 and 5, the heat exchangers 30 are independently provided on three of the four side surfaces of the housing 40, specifically, on a first surface 40a which is the right side surface, a second surface 40b which is the left side surface, and a third surface 40c which is the rear surface. Note that it is sufficient that the multiple heat exchangers 30 are arranged on at least two of the four side surfaces of the housing 40.

[0040] The heat exchanger 30 is installed inside the housing 40 so as to cover the air inlet 40f of the housing 40. Air flowing from the outside of the housing 40 into the inside due to operation of the fan 18 flows in through the air inlet 40f of the housing 40, passes between the heat transfer tubes 34 of the heat exchanger 30 (described later), heads toward the fan 18 installed above, and is discharged to the outside of the housing 40 through the air outlet 41. The specific configuration of the heat exchanger 30 will be described later.

[0041] Each of the multiple heat exchangers 30 is connected to the piping section 110 so that the flows of refrigerant passing through the multiple heat exchangers 30 are parallel to each other. In the air conditioning apparatus 1 constituting the refrigerant circuit 100 shown in Fig. 1, when the outdoor unit 10 is an evaporator, each of the multiple heat exchangers 30 is configured so that the flows of refrigerant passing through the multiple heat exchangers 30 are parallel to each other. As shown in Fig. 6, when the housing 40 is viewed from above, the multiple heat exchangers 30 are arranged so that they do not overlap with each other in the direction in which air flows from the outside to the inside of the housing 40.

[0042] Internal components 19 of the outdoor unit 10, such as the compressor 11 and the accumulator 16, are installed on the bottom 40e of the housing 40. The internal components 19 are arranged inside the housing 40 closer to the center of the housing 40 than the multiple heat exchangers 30. The internal components 19 are arranged on an air path leading from any one of the multiple heat exchangers 30 to the fan 18, generating ventilation resistance.

[0043] The compressor 11 may include a compressor case 11 a formed in a box shape. In this case, the compressor 11 is housed in the compressor case 11 a formed in a box shape. In this case, the compressor case 11 a is included in the internal parts 19.

[0044] The fan 18 is, for example, a propeller fan, and is disposed inside the housing 40 at the top of the housing 40. The fan 18 is a blowing means equipped with an axial fan, and forms an air flow for efficient heat exchange in the heat exchanger 30.

[0045] The fan 18 takes in air from the side of the housing 40, passes the air through the heat exchangers 30, and then blows the air upward from the air outlet 41. The number of fans 18 is not limited to one, and multiple fans 18 may be used. The outdoor unit 10 only needs to have at least one fan 18.

[0046] As shown in FIG. 6 , the piping unit 110 is a pipe through which a refrigerant flows, is provided upstream of the plurality of heat exchangers 30 in the refrigerant flow direction, and branches and connects to the plurality of heat exchangers 30. The piping unit 110 branches into at least two or more branches. The piping unit 110 may branch at multiple locations in the refrigerant flow direction, or may branch into multiple branches at the same location. The piping unit 110 constitutes a part of the refrigerant circuit 100. The piping unit 110 is part of the plurality of pipes 101, and is part of the pipes 101 that constitute the outdoor unit 10. In other words, the plurality of pipes 101 includes the piping unit 110. The piping unit 110 may be composed of one pipe 101 or multiple pipes 101.

[0047] [Configuration of heat exchanger 30] Fig. 7 is a perspective view that schematically shows the heat exchanger 30 of the air conditioning apparatus 1 according to embodiment 1. The outline arrows in Fig. 7 indicate the direction of air flow, and the solid arrows in Fig. 7 indicate the flow of refrigerant. The refrigerant inlet and outlet shown in Fig. 7 indicate the inlet and outlet when the heat exchanger 30 functions as an evaporator.

[0048] The heat exchanger 30 is disposed inside the housing 40 and has a plurality of heat transfer tubes 34 extending in the vertical direction, thereby exchanging heat between the refrigerant and the air. The heat exchangers 30a, 30b, and 30c are of a corrugated fin tube type having parallel piping. As shown in FIG. 1 , the heat exchangers 30a, 30b, and 30c are connected in parallel in the refrigerant circuit 100. That is, the plurality of heat exchangers 30 are connected in parallel.

[0049] 7, each of the heat exchangers 30 has a plurality of heat transfer tubes 34, a plurality of fins 35, two distribution headers 31, a first distribution header 31A and a second distribution header 31B, and a turn-up header 33. Note that, hereinafter, the distribution headers 31 and the turn-up headers 33 will also be simply referred to as "headers." Furthermore, the "distribution header 31" is a general term for the first distribution header 31A and the second distribution header 31B.

[0050] (Heat Transfer Tubes 34) Each of the plurality of heat exchangers 30 has a plurality of heat transfer tubes 34 extending in the vertical direction between the two distribution headers 31 and the turn-back header 33. The plurality of heat transfer tubes 34 are arranged perpendicular to the distribution header 31 and the turn-back header 33 and parallel to one another.

[0051] The heat transfer tubes 34 are arranged in parallel in the horizontal direction at intervals so that the air generated by the fan 18 can flow through them. The heat transfer tubes 34 are arranged at intervals along the extension direction of the first distribution header 31A, the second distribution header 31B, and the turn-back header 33. A refrigerant flows through the heat transfer tubes 34 along the extension direction of the heat transfer tubes 34. The heat transfer tubes 34 are, for example, flat tubes. The heat transfer tubes 34 are not limited to flat tubes, and may be tubes of other shapes, such as circular tubes.

[0052] When the heat transfer tubes 34 are flat tubes, the heat transfer tubes 34 have a flat cross section, and the outer surface on the long side of the flat shape along the air flow direction is flat, and the outer surface on the short side perpendicular to the long side is curved. Also, when the heat transfer tubes 34 are flat tubes, the heat transfer tubes 34 are multi-hole flat tubes having multiple holes inside the tube that serve as refrigerant flow paths. The holes that serve as the piping of the heat transfer tubes 34 are formed facing the height direction because they serve as flow paths between the distribution header 31 and the turn-back header 33.

[0053] When the heat transfer tubes 34 are flat tubes, the heat transfer tubes 34 are arranged horizontally at equal intervals with their outer surfaces facing each other along their longitudinal sides. When manufacturing the heat exchanger 30, each heat transfer tube 34 is inserted into an insertion hole (not shown) formed in the distribution header 31 and the turn-up header 33, and is brazed and joined to the distribution header 31 and the turn-up header 33. A brazing filler metal containing aluminum, for example, is used for the brazing. As a result, in the heat exchanger 30, the distribution header 31, the turn-up header 33, and the interiors of each heat transfer tube 34 are in communication with each other. Fins 35 are arranged between adjacent heat transfer tubes 34.

[0054] (Fins 35) The fins 35 are heat transfer promoting members, and are disposed between adjacent heat transfer tubes 34 among the plurality of heat transfer tubes 34, and are connected to the heat transfer tubes 34. The fins 35 are connected across the spaces between adjacent heat transfer tubes 34, and transfer heat between the connected heat transfer tubes 34. The fins 35 improve the heat exchange efficiency between the air and the refrigerant, and for example, corrugated fins are used as the fins 35.

[0055] 7 has flat tubes as the heat transfer tubes 34 and corrugated fins as the fins 35. In the heat exchanger 30, the fins 35 and the heat transfer tubes 34 are alternately arranged in the arrangement direction of the heat transfer tubes 34, i.e., in the axial direction of the folded header 33. When the fins 35 are corrugated fins, the fins 35 have a corrugated shape and are arranged between two adjacent heat transfer tubes 34, with multiple apexes of the fins 35 joined to the flat surfaces of the heat transfer tubes 34.

[0056] The fins 35 are not limited to corrugated fins, and may be other heat transfer promoting members such as plate fins. Furthermore, the heat exchanger 30 does not necessarily have to have fins 35 because heat exchange between the air and the refrigerant occurs on the surfaces of the heat transfer tubes 34. The heat transfer tubes 34, the fins 35, etc. constitute the heat exchange element 130.

[0057] (Heat exchange element 130) As shown in Fig. 7 , each of the multiple heat exchangers 30 has multiple heat exchange elements 130 arranged in the air flow direction. The heat exchange element 130 has multiple heat transfer tubes 34 arranged horizontally at intervals, with the extension direction of the heat transfer tubes 34 in the vertical direction. The heat exchange element 130 also has fins 35 joined to the heat transfer tubes 34. Note that if the heat exchanger 30 does not have fins 35, the heat exchange element 130 may be composed only of the multiple heat transfer tubes 34. In Fig. 7 , two heat exchange elements 130 of the same size are arranged side by side in the air flow direction.

[0058] Each of the multiple heat exchange elements 130 has a first heat exchange element 131 having multiple heat transfer tubes 34 arranged at intervals from one another, and a second heat exchange element 132 having multiple heat transfer tubes 34 arranged at intervals from one another. The first heat exchange element 131 is one of the multiple heat exchange elements 130, and the second heat exchange element 132 is another of the multiple heat exchange elements 130. The heat exchange element 130 is a general term for the first heat exchange element 131 and the second heat exchange element 132.

[0059] 7, the heat exchanger 30 has the heat exchange elements 130 arranged in two rows, but is not limited to this configuration and may have only one row or three or more rows of the heat exchange elements 130. When there is only one row of the heat exchange elements 130, the heat exchange elements 130 are connected to one distribution header 31.

[0060] In the heat exchanger 30 according to the first embodiment, a pair of headers consisting of two distribution headers 31 and a folded header 33 are arranged above and below in the height direction. In the outdoor unit 10, devices such as the compressor 11 are installed below the outdoor unit 10, so the folded header 33 is arranged above and the two distribution headers 31 are arranged below the folded header 33 due to piping connections and the like.

[0061] (Distribution header 31) The distribution headers 31 are each connected to other devices that make up the air conditioning apparatus 1, and are pipes through which a refrigerant, a fluid that serves as a heat exchange medium, flows in and out, and through which the refrigerant branches or merges. The distribution header 31 is a collective term for the first distribution header 31A and the second distribution header 31B. The distribution header 31 has refrigerant inlet and outlet pipes 32 through which refrigerant from the outside flows in and out.

[0062] A first distribution header 31A is provided below the first heat exchange body 131. The lower ends of the heat transfer tubes 34 that constitute the first heat exchange body 131 are directly inserted into the first distribution header 31A. The first distribution header 31A is connected to the piping 101 that constitutes the refrigerant circuit 100 of the air conditioning apparatus 1 via refrigerant inlet and outlet pipes 32A.

[0063] The first distribution header 31A is in communication with the internal space of the heat transfer tubes 34 that constitute the first heat exchange element 131. The first distribution header 31A forms a space that merges the refrigerant that flows into the first distribution header 31A from the heat transfer tubes 34 that constitute the first heat exchange element 131. Alternatively, the first distribution header 31A forms a space that distributes the refrigerant that flows into the first distribution header 31A from the outside to the heat transfer tubes 34 that constitute the first heat exchange element 131.

[0064] A second distribution header 31B is provided below the second heat exchange body 132. The lower ends of the heat transfer tubes 34 that constitute the second heat exchange body 132 are directly inserted into the second distribution header 31B. The second distribution header 31B is arranged in parallel with the first distribution header 31A. The second distribution header 31B is connected to the piping 101 that constitutes the refrigerant circuit 100 of the air conditioning apparatus 1 via refrigerant inlet and outlet pipes 32B.

[0065] The second distribution header 31B is in communication with the internal space of the heat transfer tubes 34 that constitute the second heat exchange element 132. The second distribution header 31B constitutes a space that distributes the refrigerant that flows from the outside of the second distribution header 31B to the heat transfer tubes 34 that constitute the second heat exchange element 132. Alternatively, the second distribution header 31B constitutes a space that merges the refrigerant that flows into the second distribution header 31B from the heat transfer tubes 34 that constitute the second heat exchange element 132.

[0066] FIG. 8 is a conceptual diagram showing the configuration of the distribution header 31 of the heat exchanger 30 of the first embodiment. The solid arrows in FIG. 8 indicate the direction of refrigerant flow. The tubular structure of the distribution header 31 will be described using FIG. 8 . The distribution header 31 functions as a distribution mechanism that distributes refrigerant to multiple heat transfer tubes 34. The distribution header 31 has a double-tube structure including a cylindrical inner tube portion 36 having multiple distribution holes 39 formed therein and distributing the refrigerant to the multiple heat transfer tubes 34, and an outer tube portion 37 that houses the inner tube portion 36 and into which the multiple heat transfer tubes 34 are inserted. The inner tube portion 36 constitutes the cylindrical inner tube of the distribution header 31, and the outer tube portion 37 constitutes the cylindrical outer tube of the distribution header 31.

[0067] The inner pipe portion 36 functions as a refrigerant distributor that distributes refrigerant to the multiple heat transfer pipes 34. The inner pipe portion 36 is a long, cylindrical member with a space formed therein. The inner pipe portion 36 is housed inside the outer pipe portion 37. The inner pipe portion 36 is disposed inside the outer pipe portion 37 with its pipe axis direction held horizontal. In the axial direction, one end of the inner pipe portion 36 is connected to the refrigerant inlet / outlet pipe 32 and is connected to the piping 101 (see FIG. 1 ) through the refrigerant inlet / outlet pipe 32, and the other end is sealed with a cap 38.

[0068] A plurality of distribution holes 39, which are through-holes, are formed in the inner pipe portion 36. The distribution holes 39 are also called orifice holes. The plurality of distribution holes 39 are provided along the axial direction of the inner pipe portion 36. The plurality of distribution holes 39 are formed in the inner pipe portion 36 at intervals in the longitudinal direction of the inner pipe portion 36.

[0069] The plurality of distribution holes 39 are provided in the inner pipe portion 36 at least in a range facing the plurality of heat transfer tubes 34 inserted in the outer pipe portion 37. Each of the plurality of distribution holes 39 is formed at a position between adjacent heat transfer tubes 34 in the axial direction of the outer pipe portion 37. Note that the distribution holes 39 may also be formed at a position in the inner pipe portion 36 immediately below the heat transfer tube 34. The refrigerant flowing inside the inner pipe portion 36 passes through the distribution holes 39 and flows out of the inner pipe portion 36.

[0070] The outer pipe portion 37 is a long, cylindrical member whose both ends are closed except for the connection portions of the refrigerant inlet / outlet pipes 32, and has an internal space. The outer pipe portion 37 is cylindrically formed with an inner diameter larger than that of the inner pipe portion 36. The outer pipe portion 37 houses the inner pipe portion 36 inside. A plurality of heat transfer pipes 34 are connected to the outer peripheral surface of the outer pipe portion 37. The distribution header 31 forms a space between the cylindrical outer pipe portion 37 and the inner pipe portion 36.

[0071] In the distribution header 31, the refrigerant flows into one end of the inner pipe section 36 via the refrigerant inlet / outlet pipe 32. The refrigerant that flows into the interior of the inner pipe section 36 flows out of the inner pipe section 36 through a plurality of distribution holes 39 and into the space between the inner pipe section 36 and the outer pipe section 37. The refrigerant that flows out of the inner pipe section 36 and into the space between the inner pipe section 36 and the outer pipe section 37 is distributed to the plurality of heat transfer pipes 34. By providing a plurality of distribution holes 39 arranged side by side in the inner pipe section 36 through which the refrigerant flows, the heat exchanger 30 allows the refrigerant to flow evenly through the plurality of heat transfer pipes 34 of the heat exchanger 30, improving the performance of the heat exchanger 30.

[0072] (Folded headers 33) Folded headers 33 are provided at the top of the heat exchange elements 130, into which the upper ends of the heat transfer tubes 34 inserted into the first distribution header 31A and the second distribution header 31B are inserted. That is, each of the heat exchangers 30 has a folded header 33 into which the upper ends of the heat transfer tubes 34 constituting the first heat exchange element 131 and the second heat exchange element 132 are inserted, allowing the refrigerant to circulate between the first heat exchange element 131 and the second heat exchange element 132. The folded header 33 connects the tops of the first heat exchange element 131 and the second heat exchange element 132.

[0073] The turnaround header 33 is a header that acts as a bridge to turn the flow of refrigerant from a heat exchange body 130, which is a group of heat transfer tubes 34 in one row, to a heat exchange body 130, which is a group of heat transfer tubes 34 in the other row.

[0074] The turn-back header 33 is formed in a box shape, for example, a rectangular parallelepiped shape. The turn-back header 33 is provided at the end of the plurality of heat transfer tubes 34 on the side opposite to the connection side of the two headers, the first distribution header 31A and the second distribution header 31B. The turn-back header 33 is provided opposite the first distribution header 31A and the second distribution header 31B via the heat transfer tubes 34.

[0075] The turn-back header 33 circulates refrigerant between a plurality of heat transfer tubes 34 connected to one of the first distribution header 31A and the second distribution header 31B and a plurality of heat transfer tubes 34 connected to the other header. The turn-back header 33 circulates refrigerant flowing through the first heat exchange body 131 to the second heat exchange body 132 that faces the first heat exchange body 131 in the short direction. The turn-back header 33 forms a flow path that communicates with each of the heat transfer tubes 34 that are arranged opposite each other in the short direction.

[0076] The heat transfer tubes 34, fins 35, first distribution header 31A, second distribution header 31B, return header 33, and refrigerant inlet / outlet pipes 32 such as refrigerant inlet / outlet pipes 32A and 32B are made of aluminum, for example, and joined by brazing. Note that the heat transfer tubes 34, fins 35, first distribution header 31A, second distribution header 31B, return header 33, and refrigerant inlet / outlet pipes 32 are not limited to being made of aluminum, and may be made of other materials.

[0077] Next, an example of the operation of the air conditioning apparatus 1 during each operation will be described with reference to FIG.

[0078] <Cooling operation> In cooling operation, the flow path switching device 12 is switched so that the discharge side of the compressor 11 is connected to the heat exchanger 30, the on-off valve 14 is opened, the flow control valve 13a is fully closed, and the flow control valve 13b is opened. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the heat exchangers 30a and 30b via the flow path switching device 12.

[0079] The high-temperature, high-pressure gas refrigerant that flows into the heat exchangers 30a and 30b exchanges heat with the outdoor air taken in by the fan 18, condenses while releasing heat, and flows out of the heat exchangers 30a and 30b as a medium-temperature, high-pressure, two-phase gas-liquid refrigerant. The medium-temperature, high-pressure, two-phase gas-liquid refrigerant that flows out of the heat exchangers 30a and 30b flows into the heat exchanger 30c via the on-off valve 14. The medium-temperature, high-pressure, two-phase gas-liquid refrigerant that flows into the heat exchanger 30c exchanges heat with the outdoor air taken in by the fan 18, condenses while releasing heat, and flows out of the heat exchanger 30c as a low-temperature, high-pressure liquid refrigerant.

[0080] During cooling operation, the refrigerant circuit 100 is configured so that refrigerant flows in series through the heat exchangers 30a and 30b, which are arranged in parallel and are upstream of the plurality of heat exchangers 30, and the heat exchanger 30c, which is downstream of the plurality of heat exchangers 30. The low-temperature, high-pressure liquid refrigerant flowing out of the heat exchanger 30c flows through the flow control valve 13b to the expansion device 21, where it is decompressed to become a low-temperature, low-pressure two-phase gas-liquid refrigerant, and flows into the indoor heat exchanger 22.

[0081] The low-temperature, low-pressure two-phase gas-liquid refrigerant that has flowed into the indoor heat exchanger 22 exchanges heat with the indoor air taken in by the indoor fan 23, evaporating while absorbing heat, cooling the indoor air, and turning into low-temperature, low-pressure gas refrigerant, which then flows out of the indoor heat exchanger 22. The low-temperature, low-pressure gas refrigerant that has flowed out of the indoor heat exchanger 22 is drawn into the compressor 11 via the flow switching device 12 and the accumulator 16, where it turns into high-temperature, high-pressure gas refrigerant again and is then discharged.

[0082] <Heating operation> In heating operation, the flow path switching device 12 is switched so that the discharge side of the compressor 11 is connected to the indoor heat exchanger 22, the on-off valve 14 is closed, and the flow rate adjustment valves 13 a and 13 b are open. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the indoor heat exchanger 22 via the flow path switching device 12.

[0083] The high-temperature, high-pressure gas refrigerant that flows into the indoor heat exchanger 22 exchanges heat with the indoor air taken in by the indoor fan 23, condensing while releasing heat, heating the indoor air, and then flows out of the indoor heat exchanger 22 as a low-temperature, high-pressure liquid refrigerant.

[0084] The low-temperature, high-pressure liquid refrigerant flowing out of the indoor heat exchanger 22 flows into the expansion device 21, where it is decompressed to become a low-temperature, low-pressure two-phase gas-liquid refrigerant, which then flows into the heat exchangers 30a, 30b, and 30c via the flow control valves 13a and 13b. The low-temperature, low-pressure two-phase gas-liquid refrigerant that has flowed into the heat exchangers 30a, 30b, and 30c exchanges heat with the outdoor air taken in by the fan 18, evaporates while absorbing heat, and becomes a low-temperature, low-pressure gas refrigerant. The refrigerant that has become a low-temperature, low-pressure gas refrigerant through heat exchange flows out of the heat exchangers 30a, 30b, and 30c.

[0085] During heating operation, the refrigerant circuit 100 is configured so that the refrigerant flows in parallel through the heat exchangers 30 a, 30 b, and 30 c. The low-temperature, low-pressure gas refrigerant flowing out of the heat exchangers 30 a, 30 b, and 30 c is drawn into the compressor 11 via the flow switching device 12 and the accumulator 16, where it becomes high-temperature, high-pressure gas refrigerant again and is discharged.

[0086] <Defrosting Operation> When heating operation is performed in a low-temperature environment where the surface temperatures of the heat transfer tubes 34 and fins 35 shown in Fig. 2 are below 0°C, frost forms on the heat exchanger 30. When the amount of frost on the heat exchanger 30 exceeds a certain level, the air passage of the heat exchanger 30 through which the air generated by the fan 18 passes is blocked, reducing the performance of the heat exchanger 30 and reducing heating performance. Therefore, under low outdoor air temperatures that would cause frost to form on the heat exchanger 30, a defrosting operation is performed to melt the frost on the surface of the heat exchanger 30 in order to prevent a reduction in heating performance.

[0087] In the defrosting operation, the indoor fan 23 is stopped, the flow path switching device 12 is switched to the same state as in the cooling operation, and the on-off valve 14 and the flow rate control valves 13a and 13b are also in the same states as in the cooling operation. In the defrosting operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the heat exchangers 30a and 30b, and then into the heat exchanger 30c. In the defrosting operation, as in the refrigeration operation, the refrigerant circuit 100 is configured so that the refrigerant flows in series through the heat exchangers 30a and 30b, which are arranged in parallel on the upstream side, and the heat exchanger 30c, which is located downstream, among the multiple heat exchangers 30.

[0088] During defrosting operation, the refrigerant with a higher temperature flows first through the upstream heat exchangers 30a and 30b, and then the refrigerant that has exchanged heat with the outdoor air in the upstream heat exchangers 30a and 30b and has its temperature reduced flows through the downstream heat exchanger 30c. Therefore, even if factors that hinder defrosting, such as outside wind, are different for each of the heat exchangers 30a, 30b, and 30c, the order in which defrosting is completed is first for the upstream heat exchangers 30a and 30b, and then for the downstream heat exchanger 30c.

[0089] Since the downstream heat exchanger 30c is the last to complete defrosting, by confirming that the defrosting of the downstream heat exchanger 30c is complete, it can be determined that the defrosting of all heat exchangers 30 is complete. As a result, it is only necessary to provide the same number of temperature sensors 17 as the number of downstream heat exchangers 30c, which enables cost reduction compared to the conventional method. In addition, since the number of heat exchangers 30 for which the completion of defrosting is confirmed can be reduced, the complexity of the algorithm can be reduced compared to the conventional method. Here, whether the defrosting of all heat exchangers 30 is complete is determined based on the detection value of the temperature sensor 17 and a preset threshold value. If the detection value of the temperature sensor 17 is equal to or greater than the threshold value, it is determined that the defrosting is complete.

[0090] In the first embodiment, the flow rate control valve 13 is configured to be capable of adjusting the opening degree, but is not limited to this and may be configured as a two-way valve that simply opens and closes, etc. However, if the flow rate control valves 13a and 13b are configured to be capable of adjusting the opening degree, the amount of frost formed on the plurality of heat exchangers 30 functioning as evaporators can be adjusted by adjusting the opening degree of the flow rate control valves 13a and 13b, respectively, during heating operation.

[0091] (Flow rate adjustment mechanism 50) Figure 9 is a refrigerant circuit diagram showing an example of a flow rate adjustment mechanism 50 of the air conditioning apparatus 1 according to embodiment 1. Figure 10 is a conceptual diagram showing an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of the air conditioning apparatus 1 according to embodiment 1. Figure 11 is a conceptual diagram for explaining an example of the flow rate adjustment mechanism 50 of Figures 9 and 10. An example of the flow rate adjustment mechanism 50 will be explained using Figures 9 to 11.

[0092] The outdoor unit 10 includes a flow rate adjustment mechanism 50 that adjusts the flow rate of the refrigerant flowing into the plurality of heat transfer tubes 34. More specifically, at least one of the plurality of heat exchangers 30 or the piping section 110 included in the outdoor unit 10 includes a flow rate adjustment mechanism 50 that adjusts the flow rate of the refrigerant flowing into the plurality of heat transfer tubes 34. The flow rate adjustment mechanism 50 shown in Figures 9 to 11 is constituted by the piping section 110.

[0093] The flow rate adjustment mechanism 50 adjusts the flow rate of the refrigerant flowing into the heat transfer tubes 34. Of the heat exchangers 30, the heat exchanger 30 closest to the internal component 19 is referred to as the first heat exchanger 231, and all the other heat exchangers 30 other than the first heat exchanger 231 are referred to as the second heat exchanger 232. In the case of the heat exchangers 30 shown in FIGS. 9 to 11 , the heat exchanger 30a is the first heat exchanger 231, and the heat exchangers 30b and 30c are the second heat exchangers 232.

[0094] The plurality of heat exchangers 30 are configured by a flow rate adjustment mechanism 50 so that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing to the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing to the second heat exchanger 232. A specific configuration for creating a difference between the refrigerant flow rate of the heat transfer tubes 34 in the first heat exchanger 231 and the refrigerant flow rate of the heat transfer tubes 34 in the second heat exchanger 232 will be described below.

[0095] The piping section 110 includes a first piping section 111 and a second piping section 112 in the piping section from the most upstream branching section P1 of the piping section 110 to the inlet sections E1 of the multiple heat exchangers 30. In Figures 9 and 10, the first piping section 111 is indicated by a long dashed line, and the second piping section 112 is indicated by a short dashed line. The first piping section 111 is a piping section connected to the first heat exchanger 231 in the piping section from the most upstream branching section P1 of the piping section 110 to the inlet sections E1 of the multiple heat exchangers 30. The second piping section 112 is a piping section connected to the second heat exchanger 232 in the piping section from the most upstream branching section P1 of the piping section 110 to the inlet sections E1 of the multiple heat exchangers 30.

[0096] 9 and 10, the first piping section 111 is the piping section from the branching point P1 to the inlet point E1 of the heat exchanger 30a. The second piping section 112 is the piping section from the branching point P1 to the inlet point E1 of the heat exchanger 30b. The second piping section 112 is the piping section from the branching point P1 to the inlet point E1 of the heat exchanger 30c.

[0097] The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The plurality of heat exchangers 30 have different shapes of the first piping section 111 and the second piping section 112, which are the flow rate adjustment mechanisms 50. Due to the difference between the shapes of the first piping section 111 and the second piping section 112, the plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232.

[0098] Here, in the piping section 110, the length of the piping from the most upstream branch portion P1 of the piping section 110 to the inlet portions E1 of the multiple heat exchangers is defined as piping length L. As shown in FIG. 11 , in the piping section 110, the length of the piping of the first piping section 111 is defined as piping length L1, and the length of the piping of the second piping section 112 is defined as piping length L2. Note that FIG. 11 conceptually illustrates the portions that make up the piping length L1 and the piping length L2 and does not specify the shapes of the first piping section 111 and the second piping section 112. That is, although the first piping section 111 and the second piping section 112 in FIG. 11 are shown as straight lines, the first piping section 111 and the second piping section 112 may include curved portions.

[0099] The piping length L1 is the length from the branching portion P1 to the inlet portion E1 of the heat exchanger 30a shown in Figures 9 and 10. The piping length L2 is the length from the branching portion P1 to the inlet portion E1 of the heat exchanger 30b shown in Figures 9 and 10. The piping length L1 is the length from the branching portion P1 to the inlet portion E1 of the heat exchanger 30c shown in Figures 9 and 10.

[0100] The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The flow rate adjustment mechanism 50 is configured so that the piping length L1 of the first piping section 111 is longer than the piping length L2 of the second piping section 112. Because the flow rate adjustment mechanism 50 is configured so that the piping length L1 of the first piping section 111 is longer than the piping length L2 of the second piping section 112, the pressure loss of the refrigerant flowing through the first piping section 111 is greater than the pressure loss of the refrigerant flowing through the second piping section 112. Therefore, by including the flow rate adjustment mechanism 50, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the second heat exchanger 232.

[0101] Fig. 12 is a refrigerant circuit diagram of a first modified example of the air conditioning apparatus 1 pertaining to Embodiment 1. The number of heat exchangers 30 is not limited to three and may be two, or four or more. For example, when the number of heat exchangers 30 is four, the refrigerant circuit 100 has a configuration as shown in Fig. 12. In other words, in the refrigerant circuit 100, the heat exchanger 30d and the flow rate control valve 13c are connected in parallel to the heat exchanger 30c and the flow rate control valve 13b.

[0102] During cooling operation, the refrigerant circuit 100 is configured so that refrigerant flows in series through the upstream heat exchangers 30a and 30b and the downstream heat exchangers 30c and 30d among the plurality of heat exchangers 30. During heating operation and defrosting operation, the refrigerant circuit 100 is configured so that refrigerant flows in parallel through the plurality of heat exchangers 30, namely, the heat exchangers 30a, 30b, 30c, and 30d.

[0103] A temperature sensor 17 is provided on the pipe 101a1 between the heat exchanger 30c and the flow rate control valve 13b, and on the pipe 101a2 between the heat exchanger 30d and the flow rate control valve 13c. That is, a temperature sensor 17 is provided on the pipe 101a1 and the pipe 101a2 on the outlet side of the heat exchanger 30c and the heat exchanger 30d, which are downstream during cooling operation and defrosting operation. Whether defrosting has been completed for all the heat exchangers 30 is determined based on the detection value of the temperature sensor 17 and a preset threshold value. If the detection values ​​of both temperature sensors 17 are equal to or greater than the threshold value, it is determined that defrosting has been completed.

[0104] In the case of the outdoor unit 10 of the first modified example in Fig. 12 , the heat exchanger 30a is the first heat exchanger 231, and the heat exchangers 30b, 30c, 30d, etc. are the second heat exchangers 232. The first piping section 111 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30a. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30b. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30c. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30d.

[0105] FIG. 13 is a refrigerant circuit diagram of a second modified example of the air conditioning apparatus 1 according to Embodiment 1. For example, when the number of heat exchangers 30 is four, the refrigerant circuit 100 may be configured as shown in FIG. 13. That is, during cooling operation, the refrigerant circuit 100 is configured so that refrigerant flows in series through the upstream heat exchangers 30a, 30b, and 30c of the multiple heat exchangers 30 and the downstream heat exchanger 30d. Furthermore, during heating operation and defrosting operation, the refrigerant circuit 100 is configured so that refrigerant flows in parallel through the multiple heat exchangers 30, namely, the heat exchangers 30a, 30b, 30c, and 30d.

[0106] A temperature sensor 17 is provided in the pipe 101a between the heat exchanger 30d and the flow rate control valve 13b. That is, only one temperature sensor 17 is provided in the pipe 101a on the outlet side of the heat exchanger 30d, which is downstream during cooling operation and defrosting operation. Whether defrosting has been completed for all heat exchangers 30 is determined based on the detection value of the temperature sensor 17 and a preset threshold value. If the detection value of one temperature sensor 17 is equal to or greater than the threshold value, it is determined that defrosting has been completed. With this circuit configuration, only one temperature sensor 17 is required even if the number of heat exchangers 30 is five or more.

[0107] In the case of the outdoor unit 10 of the second modified example in Fig. 13 , the heat exchanger 30a is the first heat exchanger 231, and the heat exchangers 30b, 30c, 30d, etc. are the second heat exchangers 232. The first piping section 111 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30a. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30b. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30c. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30d.

[0108] FIG. 14 is a refrigerant circuit diagram of a third modified example of the air conditioning apparatus 1 according to Embodiment 1. For example, when the number of heat exchangers 30 is three, the refrigerant circuit 100 may be configured as shown in FIG. 14. The refrigerant circuit 100 is configured so that refrigerant flows in parallel through multiple heat exchangers 30, namely, heat exchanger 30a, heat exchanger 30b, and heat exchanger 30c. The flow rate control valve 13a adjusts the flow rate of refrigerant flowing into heat exchanger 30a by changing its opening degree. The flow rate control valve 13b adjusts the flow rate of refrigerant flowing into heat exchanger 30b by changing its opening degree. The flow rate control valve 13c adjusts the flow rate of refrigerant flowing into heat exchanger 30c by changing its opening degree.

[0109] In the case of the outdoor unit 10 of the third modified example in Fig. 14, the heat exchanger 30a is the first heat exchanger 231, and the heat exchangers 30b and 30c are the second heat exchangers 232. The first piping section 111 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30a. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30b. The second piping section 112 is the piping section from the branching section P1 to the inlet section E1 of the heat exchanger 30c.

[0110] [Operation and Effect of the Outdoor Unit 10 and the Air Conditioning Apparatus 1] In the outdoor unit 10, at least one of the multiple heat exchangers 30 or the piping section 110 includes a flow rate adjustment mechanism 50 that adjusts the flow rate of refrigerant flowing into the multiple heat transfer tubes 34. Of the multiple heat exchangers 30, the heat exchanger 30 that is closest to the internal component 19 is designated as a first heat exchanger 231, and all the other heat exchangers 30 other than the first heat exchanger 231 are designated as second heat exchangers 232. The multiple heat exchangers 30 of the outdoor unit 10 are configured by the flow rate adjustment mechanism 50 so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing into the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing into the second heat exchanger 232.

[0111] In a conventional system, among multiple heat exchangers, heat exchangers located near internal components that occupy a large volume, such as a compressor or accumulator, have increased ventilation resistance, reducing the amount of air passing through the heat exchanger, and causing bias in the air speed distribution, which may result in reduced heat exchange performance. In the outdoor unit 10, the internal components 19 are located near the first heat exchanger 231, so the ventilation resistance of the air passing through the first heat exchanger 231 is greater than the ventilation resistance of the air passing through the second heat exchanger 232. Furthermore, in the outdoor unit 10, the internal components 19 are located near the first heat exchanger 231, so the air speed of the air passing through the first heat exchanger 231 is smaller than the air speed of the air passing through the second heat exchanger 232. In the outdoor unit 10, bias in the air speed distribution occurs between the area where the first heat exchanger 231 is located and the area where the second heat exchanger 232 is located in the circumferential direction of the housing 40. In the outdoor unit 10, the heat load distribution in the circumferential direction of the housing 40 at the portion where the first heat exchanger 231 is disposed is smaller than the heat load distribution at the portion where the second heat exchanger 232 is disposed.

[0112] In an outdoor unit, adjusting the refrigerant flow rate in accordance with the airflow velocity distribution and heat load distribution improves the heat exchange performance of the multiple heat exchangers as a whole, compared to when the refrigerant flow rate is uniform regardless of the airflow velocity distribution and heat load distribution. The multiple heat exchangers 30 of the outdoor unit 10 are configured by a flow rate adjustment mechanism 50 so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing to the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing to the second heat exchanger 232. The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the airflow velocity distribution to reduce the impact of deterioration of the airflow velocity distribution due to internal parts 19 such as the compressor 11 or accumulator 16. Therefore, because the internal parts 19 of the outdoor unit 10 are arranged close to each other, even if the amount of air passing through one of the multiple heat exchangers 30 becomes small and an imbalance in the air speed distribution in the circumferential direction of the housing 40 occurs, the heat exchange performance of the multiple heat exchangers 30 as a whole can be improved compared to outdoor units that do not have the above configuration by controlling the refrigerant flow rate flowing through the multiple heat exchangers 30, etc.

[0113] The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232 due to the difference between the shape of the first piping section 111 and the shape of the second piping section 112.

[0114] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0115] Furthermore, the plurality of heat exchangers 30 are configured such that the piping length L1 of the first piping section 111 is longer than the piping length L2 of the second piping section 112. By having this configuration, the plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232.

[0116] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0117] Furthermore, the internal parts 19 are configured by either or both of a compressor 11 that compresses and discharges the refrigerant or an accumulator 16 that stores liquid refrigerant inside the housing 40. By arranging the internal parts 19 closely together, the outdoor unit 10 can improve the heat exchange performance of the entire plurality of heat exchangers 30 compared to outdoor units that do not have the above configuration by controlling the refrigerant flow rate and the like flowing through the plurality of heat exchangers 30, even if the air volume passing through one of the plurality of heat exchangers 30 becomes small and a bias in the air velocity distribution in the circumferential direction of the housing 40 occurs.

[0118] The air conditioning apparatus 1 according to the first embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0119] Embodiment 2. Figure 15 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to embodiment 2. In embodiment 2, the configuration of the flow rate adjustment mechanism 50 differs from embodiment 1. Hereinafter, embodiment 2 will be explained, but explanations of parts that overlap with embodiment 1 will be omitted, and parts that are the same as or equivalent to embodiment 1 will be assigned the same reference numerals.

[0120] 15 according to the second embodiment is configured with a piping section 110. The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232 due to the difference in shape between the first piping section 111 and the second piping section 112 that constitute the flow rate adjustment mechanism 50.

[0121] The piping section 110 in the flow rate adjustment mechanism 50 according to the second embodiment includes bent sections 113, which are sections where the piping is bent in the piping section 110. In the piping section 110 in the flow rate adjustment mechanism 50 according to the second embodiment, the number of bent sections 113 formed in the first piping section 111 is greater than the number of bent sections 113 formed in the second piping section 112. In FIG. 15 , the angle of the bent sections 113 is formed at approximately 90 degrees, but the angle of the bent sections 113 is not limited to 90 degrees and may be other angles, such as 180 degrees. Furthermore, the bent sections 113 may be bent horizontally or vertically. The number of bent sections 113 is not limited to the number illustrated in FIG. 15 .

[0122] In the flow rate adjustment mechanism 50, the number of bent portions 113 formed in the first piping portion 111 is greater than the number of bent portions 113 formed in the second piping portion 112, so that the pressure loss of the refrigerant flowing through the first piping portion 111 is greater than the pressure loss of the refrigerant flowing through the second piping portion 112. Therefore, by having the flow rate adjustment mechanism 50, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the second heat exchanger 232.

[0123] [Operation and Effect of the Outdoor Unit 10 and the Air Conditioning Apparatus 1] The piping section 110 of the outdoor unit 10 includes bent sections 113, which are sections where the piping is bent in the piping section 110. The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The multiple heat exchangers 30 are formed such that the number of bent sections 113 formed in the first piping section 111 is greater than the number of bent sections 113 formed in the second piping section 112. By having this configuration, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the second heat exchanger 232.

[0124] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0125] The air conditioning apparatus 1 according to the second embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0126] Embodiment 3. Figure 16 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to embodiment 3. In embodiment 3, the configuration of the flow rate adjustment mechanism 50 differs from embodiment 1 or embodiment 2. Hereinafter, embodiment 3 will be explained, but explanations of parts that overlap with embodiments 1 and 2 will be omitted, and parts that are the same as or equivalent to those in embodiments 1 and 2 will be assigned the same reference numerals.

[0127] 16 according to the third embodiment is configured with a piping section 110. The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232 due to the difference in shape between the first piping section 111 and the second piping section 112 that constitute the flow rate adjustment mechanism 50.

[0128] The piping section 110 in the flow rate adjustment mechanism 50 according to the third embodiment is formed so that the piping diameter D1 of the first piping section 111 is smaller than the piping diameter D2 of the second piping section 112. The piping diameter D1 and the piping diameter D2 are the inner diameters of the piping section 110. The piping diameter D1 and the piping diameter D2 are the inner diameters of the piping section 110 at the portions where the inner diameter is smallest.

[0129] The piping portion that defines the piping diameter D1 may be a part or all of the first piping portion 111. The piping portion that defines the piping diameter D2 may be a part or all of the second piping portion 112. In other words, the first piping portion 111 has a reduced portion 111a that defines a portion with an inner diameter smaller than the portion that defines the minimum inner diameter of the second piping portion 112.

[0130] The flow rate adjustment mechanism 50 is formed so that the pipe diameter D1 of the first pipe section 111 is smaller than the pipe diameter D2 of the second pipe section 112, and therefore the pressure loss of the refrigerant flowing through the first pipe section 111 is larger than the pressure loss of the refrigerant flowing through the second pipe section 112. Therefore, by having the flow rate adjustment mechanism 50, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the second heat exchanger 232.

[0131] [Operation and effect of the outdoor unit 10 and the air conditioning apparatus 1] The flow rate adjustment mechanism 50 of the outdoor unit 10 includes a first piping section 111 and a second piping section 112. The multiple heat exchangers 30 are formed so that the piping diameter D1 of the first piping section 111 is smaller than the piping diameter D2 of the second piping section 112. Due to this configuration, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the second heat exchanger 232.

[0132] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0133] The air conditioning apparatus 1 according to the third embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0134] Embodiment 4. Figure 17 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to embodiment 4. In embodiment 4, the configuration of the flow rate adjustment mechanism 50 differs from that of embodiments 1 to 3. Hereinafter, embodiment 4 will be explained, but explanations of parts that overlap with embodiments 1 to 3 will be omitted, and parts that are the same as or equivalent to those in embodiments 1 to 3 will be assigned the same reference numerals.

[0135] 17 according to the fourth embodiment is configured with a piping section 110. The flow rate adjustment mechanism 50 includes a first piping section 111 and a second piping section 112. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232 due to the difference in shape between the first piping section 111 and the second piping section 112 that constitute the flow rate adjustment mechanism 50.

[0136] The flow control mechanism 50 of embodiment 4 is formed so that the height difference H1 between the lowest point U1 and the highest point T1 in the vertical direction of the pipeline of the first piping section 111 is greater than the height difference H2 between the lowest point U2 and the highest point T2 in the vertical direction of the pipeline of the second piping section 112.

[0137] The flow rate adjustment mechanism 50 is formed so that the height difference H1 of the first piping portion 111 is greater than the height difference H2 of the second piping portion 112, and therefore the pressure loss of the refrigerant flowing through the first piping portion 111 is greater than the pressure loss of the refrigerant flowing through the second piping portion 112. Therefore, by having the flow rate adjustment mechanism 50, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the second heat exchanger 232.

[0138] [Operation and Effect of the Outdoor Unit 10 and the Air Conditioning Apparatus 1] The flow rate adjustment mechanism 50 of the outdoor unit 10 includes a first piping section 111 and a second piping section 112. The multiple heat exchangers 30 are formed so that the height difference H1 between the lowermost section U1 and the uppermost section T1 in the vertical direction of the piping of the first piping section 111 is greater than the height difference H2 between the lowermost section U2 and the uppermost section T2 in the vertical direction of the piping of the second piping section 112. By having this configuration, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the second heat exchanger 232.

[0139] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0140] The air conditioning apparatus 1 according to the fourth embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0141] Embodiment 5. Figure 18 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to embodiment 5. In embodiment 5, the configuration of the flow rate adjustment mechanism 50 differs from that of embodiments 1 to 4. Hereinafter, embodiment 5 will be explained, but explanations of parts that overlap with embodiments 1 to 4 will be omitted, and parts that are the same as or equivalent to those in embodiments 1 to 4 will be assigned the same reference numerals.

[0142] 18 according to the fifth embodiment is configured with a plurality of heat exchangers 30. The flow rate adjustment mechanism 50 includes a first inner pipe portion 361 that is the inner pipe portion 36 of the first heat exchanger 231 and a second inner pipe portion 362 that is the inner pipe portion 36 of the second heat exchanger 232. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing through the second heat exchanger 232 due to the difference in shape between the first inner pipe portion 361 and the second inner pipe portion 362 that are the flow rate adjustment mechanism 50.

[0143] The first inner pipe portion 361 and the second inner pipe portion 362 that constitute the flow rate adjustment mechanism 50 according to the fifth embodiment are formed so that the inner pipe cross-sectional area S1 of the first inner pipe portion 361 is smaller than the inner pipe cross-sectional area S2 of the second inner pipe portion 362. The plurality of heat exchangers 30 are configured so that the inner pipe cross-sectional area S1 of the first inner pipe portion 361 is smaller than the inner pipe cross-sectional area S2 of the second inner pipe portion 362, so that the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing in the second heat exchanger 232.

[0144] The flow rate adjustment mechanism 50 is configured so that the inner pipe cross-sectional area S1 of the first inner pipe portion 361 is smaller than the inner pipe cross-sectional area S2 of the second inner pipe portion 362, and therefore the pressure loss of the refrigerant flowing through the first inner pipe portion 361 is greater than the pressure loss of the refrigerant flowing through the second inner pipe portion 362. Therefore, by having the flow rate adjustment mechanism 50, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the second heat exchanger 232.

[0145] [Operation and effect of the outdoor unit 10 and the air conditioning apparatus 1] The flow rate adjustment mechanism 50 of the outdoor unit 10 includes a first inner pipe portion 361 that is the inner pipe portion 36 of the first heat exchanger 231, and a second inner pipe portion 362 that is the inner pipe portion 36 of the second heat exchanger 232. Due to the difference between the shape of the first inner pipe portion 361 and the shape of the second inner pipe portion 362, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing in the second heat exchanger 232.

[0146] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0147] Furthermore, the multiple heat exchangers 30 are formed so that the inner pipe cross-sectional area S1 of the first inner pipe portion 361 is smaller than the inner pipe cross-sectional area S2 of the second inner pipe portion 362. By having this configuration, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing in the second heat exchanger 232.

[0148] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0149] The air conditioning apparatus 1 according to the fifth embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0150] Sixth Embodiment Figure 19 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to a sixth embodiment. In the sixth embodiment, the configuration of the flow rate adjustment mechanism 50 differs from that of the first to fifth embodiments. Below, the sixth embodiment will be explained, but explanations of parts that overlap with the first to fifth embodiments will be omitted, and parts that are the same as or equivalent to those of the first to fifth embodiments will be given the same reference numerals.

[0151] 19 according to the sixth embodiment is configured with a plurality of heat exchangers 30. The flow rate adjustment mechanism 50 includes a first inner pipe portion 361 that is the inner pipe portion 36 of the first heat exchanger 231 and a second inner pipe portion 362 that is the inner pipe portion 36 of the second heat exchanger 232. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing through the second heat exchanger 232 due to the difference in shape between the first inner pipe portion 361 and the second inner pipe portion 362 that are the flow rate adjustment mechanism 50.

[0152] In the first inner pipe portion 361 and the second inner pipe portion 362 that constitute the flow rate adjustment mechanism 50 according to the sixth embodiment, the number of the distribution holes 39 formed in the first inner pipe portion 361 is smaller than the number of the distribution holes 39 formed in the second inner pipe portion 362. In this case, the opening diameter of the distribution holes 39 in the first inner pipe portion 361 and the opening diameter of the distribution holes 39 in the second inner pipe portion 362 are the same. In other words, the total opening area of ​​the plurality of distribution holes 39, which is the sum of the opening areas of the plurality of distribution holes 39 in the first inner pipe portion 361, is smaller than the total opening area of ​​the plurality of distribution holes 39, which is the sum of the opening areas of the plurality of distribution holes 39 in the second inner pipe portion 362.

[0153] The multiple heat exchangers 30 are configured such that the number of multiple distribution holes 39 formed in the first inner pipe portion 361 is less than the number of multiple distribution holes 39 formed in the second inner pipe portion 362, so that the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing into the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing into the second heat exchanger 232.

[0154] In the flow rate adjustment mechanism 50, the number of the plurality of distribution holes 39 formed in the first inner pipe portion 361 is smaller than the number of the plurality of distribution holes 39 formed in the second inner pipe portion 362, so that the pressure loss of the refrigerant flowing through the first inner pipe portion 361 is greater than the pressure loss of the refrigerant flowing through the second inner pipe portion 362. Therefore, by having the flow rate adjustment mechanism 50, the plurality of heat exchangers 30 are configured so that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232.

[0155] [Operation and effect of the outdoor unit 10 and the air conditioning apparatus 1] The multiple heat exchangers 30 are formed so that the number of multiple distribution holes 39 formed in the first inner pipe portion 361 is smaller than the number of multiple distribution holes 39 formed in the second inner pipe portion 362. By having the above configuration, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing in the second heat exchanger 232.

[0156] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0157] The air conditioning apparatus 1 according to the sixth embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0158] Seventh Embodiment Figure 20 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to a seventh embodiment. In the seventh embodiment, the configuration of the flow rate adjustment mechanism 50 differs from that of the first to sixth embodiments. Below, the seventh embodiment will be explained, but explanations of parts that overlap with the first to sixth embodiments will be omitted, and parts that are the same as or equivalent to those of the first to sixth embodiments will be given the same reference numerals.

[0159] 20 shows a flow rate adjustment mechanism 50 according to the seventh embodiment, which is configured with a plurality of heat exchangers 30. The flow rate adjustment mechanism 50 includes a first inner pipe portion 361 that is the inner pipe portion 36 of the first heat exchanger 231 and a second inner pipe portion 362 that is the inner pipe portion 36 of the second heat exchanger 232. The plurality of heat exchangers 30 are configured such that the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer pipes 34 flowing through the second heat exchanger 232 due to the difference in shape between the first inner pipe portion 361 and the second inner pipe portion 362 that are the flow rate adjustment mechanism 50.

[0160] In the first inner pipe portion 361 and the second inner pipe portion 362 that constitute the flow rate adjustment mechanism 50 according to the seventh embodiment, the opening diameter C1 of each of the plurality of distribution holes 39 in the first inner pipe portion 361 is smaller than the opening diameter C2 of each of the plurality of distribution holes 39 in the second inner pipe portion 362. In this case, the number of distribution holes 39 formed in the first inner pipe portion 361 is the same as the number of distribution holes 39 formed in the second inner pipe portion 362. In other words, the total opening area of ​​the plurality of distribution holes 39, which is the sum of the opening areas of each of the plurality of distribution holes 39 in the first inner pipe portion 361, is smaller than the total opening area of ​​the plurality of distribution holes 39, which is the sum of the opening areas of each of the plurality of distribution holes 39 in the second inner pipe portion 362.

[0161] The multiple heat exchangers 30 are configured such that the opening diameter C1 of each of the multiple distribution holes 39 in the first inner pipe portion 361 is smaller than the opening diameter C2 of each of the multiple distribution holes 39 in the second inner pipe portion 362, so that the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing into the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer pipes 34 flowing into the second heat exchanger 232.

[0162] The flow rate adjustment mechanism 50 is configured so that the opening diameter C1 of each of the plurality of distribution holes 39 in the first inner pipe portion 361 is smaller than the opening diameter C2 of each of the plurality of distribution holes 39 in the second inner pipe portion 362, and therefore the pressure loss of the refrigerant flowing through the first inner pipe portion 361 is greater than the pressure loss of the refrigerant flowing through the second inner pipe portion 362. Therefore, by having the flow rate adjustment mechanism 50, the plurality of heat exchangers 30 are configured so that the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the plurality of heat transfer tubes 34 flowing in the second heat exchanger 232.

[0163] [Operation and Effect of the Outdoor Unit 10 and the Air Conditioning Apparatus 1] The flow rate adjustment mechanism 50 of the outdoor unit 10 includes a first inner pipe portion 361 and a second inner pipe portion 362. In the multiple heat exchangers 30, the opening diameter C1 of each of the multiple distribution holes 39 of the first inner pipe portion 361 is smaller than the opening diameter C2 of each of the multiple distribution holes 39 of the second inner pipe portion 362. By having the above configuration, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing in the second heat exchanger 232.

[0164] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0165] The air conditioning apparatus 1 according to the seventh embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0166] Embodiment 8. Figure 21 is a conceptual diagram for explaining an example of a flow rate adjustment mechanism 50 in the outdoor unit 10 of an air conditioning apparatus 1 according to embodiment 8. Figure 22 is a conceptual diagram showing an example of an outdoor unit 10 of an air conditioning apparatus 1 according to embodiment 8. In embodiment 8, the configuration of the flow rate adjustment mechanism 50 differs from embodiments 1 to 7. Hereinafter, embodiment 8 will be explained, but explanations of parts that overlap with embodiments 1 to 7 will be omitted, and parts that are the same as or equivalent to those in embodiments 1 to 7 will be assigned the same reference numerals.

[0167] As shown in FIGS. 21 and 22 , the flow rate adjustment mechanism 50 according to the eighth embodiment is configured with a piping section 110. The piping section 110 includes at least one flow rate adjustment valve 13e. The flow rate adjustment valve 13e is, for example, an electronic expansion valve, and adjusts the flow rate of the refrigerant flowing into the heat exchanger 30 by changing its opening degree. The flow rate adjustment mechanism 50 includes the piping section 110 including at least one flow rate adjustment valve 13e. The flow rate adjustment mechanism 50 also includes a first piping section 111 and a second piping section 112. The multiple heat exchangers 30 are configured such that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing into the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing into the second heat exchanger 232 due to the difference in configuration between the first piping section 111 and the second piping section 112, which are the flow rate adjustment mechanism 50.

[0168] The outdoor unit 10 has a flow rate adjustment valve 13e in the first piping section 111. In the refrigerant circuit 100 of the outdoor unit 10 shown in Figures 21 and 22, the flow rate adjustment valve 13e is provided in the first piping section 111, but the flow rate adjustment valve 13e may also be provided in the second piping section 112. Furthermore, the flow rate adjustment valve 13a, flow rate adjustment valve 13b, flow rate adjustment valve 13c, flow rate adjustment valve 13d, or the like described above may be used as the flow rate adjustment valve 13e (see Figures 1, 12 to 14).

[0169] The flow rate adjustment mechanism 50 can make the pressure loss of the refrigerant flowing through the first piping portion 111 greater than the pressure loss of the refrigerant flowing through the second piping portion 112 by reducing the aperture of at least one or more flow rate adjustment valves 13e. Therefore, by including the flow rate adjustment mechanism 50, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the second heat exchanger 232. In other words, the multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing through the second heat exchanger 232 by reducing the aperture of at least one or more flow rate adjustment valves 13e.

[0170] [Operation and Effect of the Outdoor Unit 10 and the Air Conditioning Apparatus 1] The piping section 110 of the outdoor unit 10 includes at least one or more flow rate adjustment valves 13e. The flow rate adjustment mechanism 50 has the piping section 110 including at least one or more flow rate adjustment valves 13e. The multiple heat exchangers 30 are configured so that the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing to the first heat exchanger 231 is smaller than the refrigerant flow rate per each of the multiple heat transfer tubes 34 flowing to the second heat exchanger 232, depending on the opening degree of the at least one or more flow rate adjustment valves 13e.

[0171] The outdoor unit 10 achieves appropriate refrigerant distribution in accordance with the air velocity distribution by the above-described configuration in order to reduce the influence of deterioration of the air velocity distribution due to internal parts 19 such as the compressor 11 or the accumulator 16. Therefore, even if the air volume passing through one of the multiple heat exchangers 30 is reduced and an imbalance in the air velocity distribution in the circumferential direction of the housing 40 occurs due to the internal parts 19 being arranged closely to one another, the outdoor unit 10 can improve the heat exchange performance of the multiple heat exchangers 30 as a whole by controlling the refrigerant flow rate, etc., flowing through the multiple heat exchangers 30 compared to outdoor units not having the above-described configuration.

[0172] The air conditioning apparatus 1 according to the eighth embodiment comprises an outdoor unit 10 having the above-described configuration, and an indoor unit 20 that is connected to the outdoor unit 10 by piping through which a refrigerant flows, has an indoor heat exchanger 22, and performs heat exchange between the indoor air and the refrigerant flowing therethrough. Because the air conditioning apparatus 1 comprises the outdoor unit 10 having the above-described configuration, it can achieve the same effects as the outdoor unit 10.

[0173] The above-described first to eighth embodiments can be implemented in combination with one another. For example, the relationship between the first piping section 111 and the second piping section 112 and the relationship between the first inner pipe section 361 and the second inner pipe section 362 can be combined, and the flow rate adjustment valve 13e can be included in these relationships. The configurations shown in the above-described embodiments are merely examples, and can be combined with other known technologies. Parts of the configuration can also be omitted or modified without departing from the spirit of the invention.

[0174] 1 Air conditioning apparatus, 10 Outdoor unit, 11 Compressor, 11a Compressor case, 12 Flow path switching device, 13 Flow control valve, 13a Flow control valve, 13b Flow control valve, 13c Flow control valve, 13d Flow control valve, 13e Flow control valve, 14 Opening and closing valve, 15 Check valve, 16 Accumulator, 17 Temperature sensor, 18 Fan, 19 Internal parts, 20 Indoor unit, 21 Throttle device, 22 Indoor heat exchanger, 23 Indoor fan, 30 Heat exchanger, 30a Heat exchanger, 30b Heat exchanger, 30c Heat exchanger, 30d Heat exchanger, 31 Distribution header, 31A First distribution header, 31B Second distribution header, 32 Refrigerant inlet and outlet pipe, 32A Refrigerant inlet and outlet pipe, 32B Refrigerant inlet and outlet pipe, 33 Turned header, 34 Heat transfer tube, 35 fin, 36 inner pipe portion, 37 outer pipe portion, 38 cap, 39 distribution hole, 40 housing, 40a first surface, 40b second surface, 40c third surface, 40d fourth surface, 40e bottom portion, 40f suction port, 41 outlet port, 43 sealing plate, 45 internal space, 50 flow rate adjustment mechanism, 100 refrigerant circuit, 101 piping, 101a piping, 101a1 piping, 101a2 piping, 110 piping portion, 111 first piping portion, 111a contraction portion, 112 second piping portion, 113 bend portion, 130 heat exchange element, 131 first heat exchange element, 132 second heat exchange element, 231 first heat exchanger, 232 second heat exchanger, 361 first inner pipe portion, 362 second inner pipe portion, C1 Opening diameter, C2 opening diameter, D1 pipe diameter, D2 pipe diameter, E1 inlet section, H1 height difference, H2 height difference, P1 branch part, S1 inner pipe cross-sectional area, S2 inner pipe cross-sectional area, T1 top, T2 top, U1 bottom, U2 bottom.

Claims

1. An outdoor unit of an air conditioning system, A rectangular box-shaped enclosure with an air outlet formed on the top surface, The above-mentioned enclosure is arranged inside the housing and has multiple heat exchangers having multiple heat transfer tubes that extend in the vertical direction, which exchange heat between the refrigerant and the air, At least one fan positioned at the top of the housing, which takes in air from the side of the housing, passes it through the plurality of heat exchangers, and then blows it upward from the outlet, An internal component of the outdoor unit installed at the bottom of the housing, the internal component being positioned in the airflow path from one of the plurality of heat exchangers toward the fan and generating airflow resistance, A piping through which a refrigerant flows, provided on the upstream side of the plurality of heat exchangers in the direction of refrigerant flow, and comprising a piping section that branches and connects to the plurality of heat exchangers, Equipped with, The aforementioned plurality of heat exchangers are, It is located on at least two of the four sides of the aforementioned housing, Each of the aforementioned plurality of heat exchangers is The refrigerant flow passing through the plurality of heat exchangers is connected to the piping section in a parallel manner, At least one of the aforementioned plurality of heat exchangers or the aforementioned piping section is It includes a flow rate adjustment mechanism that adjusts the flow rate of refrigerant flowing into the interior of the plurality of heat transfer tubes, The aforementioned plurality of heat exchangers are, An outdoor unit configured such that, among the plurality of heat exchangers, the heat exchanger closest to the internal components is designated as the first heat exchanger, and all other heat exchangers (one or more heat exchangers) are designated as the second heat exchangers, the flow rate adjustment mechanism is configured such that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

2. The aforementioned piping section is In the piping section from the most upstream branching point of the piping section to the inlet points of the plurality of heat exchangers, there is a first piping section which is connected to the first heat exchanger and a second piping section which is connected to the second heat exchanger. The aforementioned flow rate adjustment mechanism is Including the first piping section and the second piping section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 1, wherein, due to the difference in shape between the first piping section and the second piping section, the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

3. In the aforementioned piping section, if the length of the piping from the upstreammost branching point of the piping section to the inlet points of the multiple heat exchangers is defined as the piping length, The aforementioned flow rate adjustment mechanism is Including the first piping section and the second piping section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 2, wherein the length of the first piping section is configured to be longer than the length of the second piping section, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

4. The aforementioned piping section is The aforementioned piping section includes a bent portion which is the part of the piping that is bent, The aforementioned flow rate adjustment mechanism is Including the first piping section and the second piping section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 2 or 3, wherein the number of bends formed in the first piping section is greater than the number of bends formed in the second piping section, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

5. The aforementioned flow rate adjustment mechanism is Including the first piping section and the second piping section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 2 or 3, wherein the diameter of the first piping section is formed to be smaller than the diameter of the second piping section, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

6. The aforementioned flow rate adjustment mechanism is Including the first piping section and the second piping section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 2 or 3, wherein the difference in height between the lowest and highest points in the vertical direction of the pipeline of the first piping section is formed to be greater than the difference in height between the lowest and highest points in the vertical direction of the pipeline of the second piping section, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

7. Each of the aforementioned plurality of heat exchangers is A first heat exchanger having multiple heat transfer tubes arranged at intervals from each other, A second heat exchanger having multiple heat transfer tubes arranged at intervals from each other, The upper ends of the plurality of heat transfer tubes constituting the first heat exchanger and the second heat exchanger are inserted into a folded header that allows refrigerant to flow between the first heat exchanger and the second heat exchanger, A double-tube distribution header having a cylindrical inner tube section with multiple distribution holes for distributing refrigerant to the multiple heat transfer tubes, and an outer tube section that houses the inner tube section and into which the multiple heat transfer tubes are inserted, It has, The aforementioned flow rate adjustment mechanism is The first heat exchanger includes a first inner tube section which is the inner tube section of the first heat exchanger, and a second inner tube section which is the inner tube section of the second heat exchanger. The aforementioned plurality of heat exchangers are, The outdoor unit according to any one of claims 1 to 3, wherein the difference between the shape of the first inner pipe section and the shape of the second inner pipe section causes the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger to be smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

8. The aforementioned flow rate adjustment mechanism is Including the first inner tube section and the second inner tube section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 7, wherein the cross-sectional area of ​​the inner tube of the first inner tube is formed to be smaller than the cross-sectional area of ​​the inner tube of the second inner tube, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

9. The aforementioned flow rate adjustment mechanism is Including the first inner tube section and the second inner tube section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 7, wherein the number of distribution holes formed in the first inner pipe section is less than the number of distribution holes formed in the second inner pipe section, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

10. The aforementioned flow rate adjustment mechanism is Including the first inner tube section and the second inner tube section, The aforementioned plurality of heat exchangers are, The outdoor unit according to claim 7, wherein the opening diameter of each of the plurality of distribution holes in the first inner pipe is formed to be smaller than the opening diameter of each of the plurality of distribution holes in the second inner pipe, so that the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger is smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

11. The aforementioned piping section is Includes at least one flow control valve, The aforementioned flow rate adjustment mechanism is The piping section includes at least one flow control valve, The aforementioned plurality of heat exchangers are, The outdoor unit according to any one of claims 1 to 3, wherein the opening of at least one of the flow control valves causes the refrigerant flow rate per heat transfer tube flowing to the first heat exchanger to be smaller than the refrigerant flow rate per heat transfer tube flowing to the second heat exchanger.

12. The aforementioned internal components are An outdoor unit according to any one of claims 1 to 3, comprising either a compressor that compresses and discharges a refrigerant, or an accumulator that stores liquid refrigerant inside the housing, or both.

13. An outdoor unit according to any one of claims 1 to 3, An indoor unit is connected to the outdoor unit by piping for the circulation of refrigerant, has an indoor heat exchanger, and performs heat exchange between indoor air and refrigerant flowing inside, An air conditioning system equipped with [specific features / features].