Heat exchanger, outdoor unit, and refrigeration cycle device

Abstract

The present invention comprises: a pair of headers that are arranged in the height direction so as to be separated from each other and in which a refrigerant passes through a cylindrical tube; a plurality of heat transfer tubes that are arranged side by side and connected in a plurality of stages with intervals therebetween in the longitudinal direction of the pair of headers, the heat transfer tubes having therein a flow path through which the refrigerant flows; and a first refrigerant inlet / outlet tube through which refrigerant in piping connected with the exterior flows in and out, said first refrigerant inlet / outlet tube being connected in the same direction as the flow paths of the plurality of heat transfer tubes to a lower header of the pair of headers which is positioned on the lower side. When the cross-sectional area ratio R of the inlet / outlet tube cross-sectional area Ap of the first refrigerant inlet / outlet tube with respect to the header cross-sectional area Ah of the lower header is defined as R = Ap / Ah, the cross-sectional area ratio R is within the range of 0.1 < R < 0.5.

Description

Heat exchanger, outdoor unit and refrigeration cycle device

[0001] The disclosed technique relates to a heat exchanger, an outdoor unit, and a refrigeration cycle device, and in particular to a heat exchanger having a header that serves as a refrigerant distributor.

[0002] In recent years, in order to reduce the amount of refrigerant used and improve the performance of heat exchangers, the heat transfer tubes in refrigeration cycle systems have been made thinner. As the heat transfer tubes become thinner, the number of branches in heat exchangers increases to suppress increases in refrigerant pressure loss. To accommodate this multi-branch distribution, heat exchangers have been developed that have horizontally long headers that act as refrigerant distributors, one above the other (see, for example, Patent Document 1).

[0003] JP 2008-008584 A

[0004] The refrigerant circuit is filled with refrigerating machine oil that lubricates the compressor, which is a component of the refrigerant circuit. The refrigerating machine oil is discharged from the compressor together with the refrigerant and circulates through the refrigerant circuit.

[0005] However, incompatible refrigeration oils, which do not dissolve in the refrigerant, may not be able to pass through the pipes like the refrigerant due to factors such as specific gravity. For this reason, in a heat exchanger having a header in the vertical direction and a refrigerant inlet / outlet pipe through which the refrigerant flows in and out from the outside, connected to the top surface of the lower header, when the refrigerant flows out from the lower header, the refrigeration oil cannot rise up the refrigerant inlet / outlet pipe and ends up accumulating in the header. Refrigeration oil accumulating in the header affects the refrigerant distribution in the heat transfer pipes and reduces the heat exchange performance of the heat exchanger.

[0006] Therefore, an object of the present invention is to provide a heat exchanger, an outdoor unit, and a refrigeration cycle device that can solve the above-mentioned problems and suppress the accumulation of refrigerating machine oil while maintaining heat exchange performance.

[0007] The heat exchanger according to this disclosure comprises a pair of headers arranged at a distance from each other in the vertical direction and through which a refrigerant passes, a plurality of heat transfer tubes connected in a row at intervals along the longitudinal direction of the pair of headers and having internal flow paths through which the refrigerant flows, and a first refrigerant inlet and outlet pipe connected to the lower header of the pair of headers, which is located lower, in the same direction as the flow paths of the heat transfer tubes and through which the refrigerant flows in and out of the connecting piping to the outside, wherein when the cross-sectional area ratio R of the inlet and outlet pipe cross-sectional area Ap of the first refrigerant inlet and outlet pipe to the header cross-sectional area Ah of the lower header is defined as R = Ap / Ah, the cross-sectional area ratio R is within the range of 0.1 < R < 0.5.

[0008] An outdoor unit according to the present disclosure includes the heat exchanger according to the present disclosure as an outdoor heat exchanger.

[0009] The refrigeration cycle device according to the present disclosure includes the outdoor unit according to the present disclosure.

[0010] According to this disclosure, by configuring the lower header and the refrigerant inlet / outlet pipes so that the cross-sectional area ratio R satisfies the relationship 0.1 < R < 0.5, it is possible to efficiently discharge refrigerating machine oil from the lower header and prevent refrigerating machine oil from accumulating while maintaining heat exchange performance.

[0011] 1 is a diagram illustrating the configuration of an air conditioning apparatus according to Embodiment 1. FIG. 2 is a diagram illustrating the configuration of a heat exchanger 1000 according to Embodiment 1. FIG. 3 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to Embodiment 1 when viewed along the Y direction. FIG. 4 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to Embodiment 1 when viewed along the X direction. FIG. 5 is a diagram illustrating the relationship between the cross-sectional area ratio R and heat exchange performance according to Embodiment 1. FIG. 6 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to Embodiment 2 when viewed along the Y direction. FIG. 7 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to Embodiment 2 when viewed along the X direction. FIG. 8 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to Embodiment 3 when viewed along the X direction. FIG. 9 is a diagram illustrating the shape of an oil orifice 1131 according to Embodiment 3 (part 1). FIG. 10 is a diagram illustrating the shape of the oil orifice 1131 according to Embodiment 3 (part 2). FIG. 11 is a diagram illustrating the shape of the oil orifice 1131 according to Embodiment 3 (part 3). FIG. 12 is a diagram illustrating the shape of the oil orifice 1131 according to Embodiment 3 (part 3). FIG. 13 is a diagram illustrating the shape of the oil orifice 1131 according to Embodiment 3 (part 3). Fig. 10 is a diagram showing a part of a cross section of a heat exchanger 1000 according to embodiment 5 when viewed along the X direction. Fig. 11 is a diagram illustrating the arrangement of an outdoor heat exchanger 230 in an outdoor unit 200 according to embodiment 6. Fig. 12 is a diagram illustrating the arrangement of an outdoor heat exchanger 230 in an outdoor unit 200 according to embodiment 7.

[0012] A heat exchanger, an outdoor unit, and a refrigeration cycle apparatus according to embodiments will be described below with reference to the drawings. In the following drawings, components with the same reference numerals are identical or equivalent and will be common throughout the following embodiments. The dimensional relationships between components in the drawings may differ from those in reality. Furthermore, in cross-sectional views, hatching is omitted in some views and devices for ease of viewing. The configurations of components shown throughout the specification are merely illustrative and are not limited to those described in the specification. In particular, the combinations of components are not limited to those in each embodiment, and components described in other embodiments may be applied to other embodiments. Furthermore, the levels of pressure and temperature are not determined in relation to absolute values, but are determined relatively based on the state, operation, etc. of the device. Furthermore, when multiple similar devices are distinguished by subscripts, the subscripts may be omitted if there is no need to distinguish or identify them.

[0013] Embodiment 1. <Configuration of Air Conditioning Apparatus> Fig. 1 is a diagram showing the configuration of an air conditioning apparatus according to Embodiment 1. Here, the air conditioning apparatus will be described as an example of a refrigeration cycle apparatus having a heat exchanger according to Embodiment 1.

[0014] As shown in FIG. 1 , the air conditioning apparatus of the first embodiment has an outdoor unit 200, an indoor unit 100, and two refrigerant pipes 300. The outdoor unit 200 is a unit having a compressor 210, a four-way valve 220, and an outdoor heat exchanger 230 as its components. The indoor unit 100 is a unit having an indoor heat exchanger 110 and an expansion valve 120 as its components. The components inside the outdoor unit 200 and the components inside the indoor unit 100 are connected by refrigerant pipes 300, forming a refrigerant circuit in which a refrigerant, a fluid that transports heat, circulates. Here, the air conditioning apparatus of the first embodiment has one outdoor unit 200 and one indoor unit 100 connected by piping. However, the number of connected units is not limited to this. Unless otherwise specified, the term "refrigerant" used below includes refrigerating machine oil.

[0015] The indoor unit 100 includes an indoor heat exchanger 110, an expansion valve 120, and an indoor fan 130. The indoor heat exchanger 110 and the expansion valve 120 are connected by piping within the indoor unit 100. The expansion valve 120, such as a throttling device, reduces the pressure of the refrigerant to expand it. If the expansion valve 120 is configured as an electronic expansion valve, for example, it adjusts its opening based on instructions from a control device (not shown). The indoor heat exchanger 110 exchanges heat between the refrigerant and the indoor air that is the space to be air-conditioned. For example, during heating operation, the indoor heat exchanger 110 functions as a condenser, condensing and liquefying the refrigerant. During cooling operation, the indoor heat exchanger 110 functions as an evaporator, evaporating and vaporizing the refrigerant. The indoor fan 130 passes indoor air through the indoor heat exchanger 110 and supplies the air that has passed through the indoor heat exchanger 110 into the room.

[0016] The outdoor unit 200 of the first embodiment has a compressor 210, a four-way valve 220, an outdoor heat exchanger 230, and an accumulator 240 as components that constitute a refrigerant circuit. These components are connected by piping inside the outdoor unit 200. The outdoor unit 200 also has an outdoor fan 250. The compressor 210 compresses and discharges the drawn refrigerant. The compressor 210 is, for example, a scroll compressor, a reciprocating compressor, or a vane compressor. Although not particularly limited, the capacity of the compressor 210 can be changed by arbitrarily changing the drive frequency using, for example, an inverter circuit or the like.

[0017] The four-way valve 220, which serves as a flow path switching device, is a valve that switches the flow of refrigerant between cooling operation and heating operation, for example. During heating operation, the four-way valve 220 connects the discharge side of the compressor 210 to the indoor heat exchanger 110 and connects the suction side of the compressor 210 to the outdoor heat exchanger 230. During cooling operation, the four-way valve 220 connects the discharge side of the compressor 210 to the outdoor heat exchanger 230 and connects the suction side of the compressor 210 to the indoor heat exchanger 110. While the four-way valve 220 is used here as an example, the flow path switching device is not limited to this. The flow path switching device may also be a device that combines multiple two-way valves, for example. The accumulator 240 is installed on the suction side of the compressor 210. The accumulator 240 allows a gaseous refrigerant (hereinafter referred to as a gas refrigerant) to pass through and stores a liquid refrigerant (hereinafter referred to as a liquid refrigerant).

[0018] The outdoor heat exchanger 230 has one or more heat exchangers 1000 that exchange heat between the refrigerant and outdoor air. For the outdoor heat exchanger 230, the refrigerant serves as a fluid that serves as a heat exchange medium. Here, the outdoor heat exchanger 230 in the first embodiment functions as an evaporator during heating operation, evaporating and vaporizing the refrigerant. On the other hand, the outdoor heat exchanger 230 functions as a condenser during cooling operation, condensing and liquefying the refrigerant. The outdoor heat exchanger 230 also functions as a condenser during defrosting operation to defrost the heat exchanger 1000. The outdoor heat exchanger 230 in the first embodiment has one heat exchanger 1000. Details of the heat exchanger 1000 will be described later. Furthermore, the outdoor fan 250, when driven, passes air from outside the outdoor unit 200 through the outdoor heat exchanger 230, forming a flow of air that flows out of the outdoor unit 200.

[0019] <Operation of the Air Conditioner> Next, the operation of each device in the air conditioner will be described based on the flow of refrigerant. First, the operation of each device in the refrigerant circuit during heating operation will be described based on the flow of refrigerant. The solid arrows in FIG. 1 indicate the flow of refrigerant during heating operation. High-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the indoor heat exchanger 110. While passing through the indoor heat exchanger 110, the gas refrigerant condenses and liquefies by, for example, exchanging heat with the air in the space to be air-conditioned. The condensed and liquefied refrigerant passes through the expansion valve 120. The refrigerant is decompressed as it passes through the expansion valve 120. The refrigerant, which has been decompressed by the expansion valve 120 and is now in a gas-liquid two-phase state, passes through the outdoor heat exchanger 230. In the outdoor heat exchanger 230, the refrigerant evaporates by exchanging heat with the outdoor air sent from the outdoor fan 250, and the gaseous refrigerant passes through the four-way valve 220 and the accumulator 240, and is again drawn into the compressor 210. In this way, the refrigerant in the air conditioner circulates to perform air conditioning related to heating.

[0020] Next, cooling operation will be described. The dotted arrows in FIG. 1 indicate the flow of refrigerant during cooling operation. High-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the outdoor heat exchanger 230. While passing through the outdoor heat exchanger 230, the gas refrigerant condenses and liquefies by exchanging heat with outdoor air supplied by the outdoor fan 250. The liquefied refrigerant may further be subcooled. The liquefied refrigerant passes through the expansion valve 120. Here, the refrigerant is decompressed as it passes through the expansion valve 120, becoming a two-phase gas-liquid state. The refrigerant decompressed and in a two-phase gas-liquid state by the expansion valve 120 passes through the indoor heat exchanger 110. In the indoor heat exchanger 110, the refrigerant evaporates by exchanging heat with, for example, the air in the space to be air-conditioned. The gas refrigerant then passes through the four-way valve 220 and is drawn back into the compressor 210. In this manner, the refrigerant in the air conditioner circulates to perform air conditioning related to cooling.

[0021] 2 is a diagram illustrating the configuration of a heat exchanger 1000 according to the first embodiment. The heat exchanger 1000 is a fin-tube heat exchanger of a parallel piping type. Hereinafter, the up-down direction of the heat exchanger 1000 is referred to as the Z direction (height direction). The direction perpendicular to the Z direction is referred to as the horizontal direction. A certain direction within the horizontal direction is referred to as the X direction (vertical-horizontal direction), and the direction perpendicular to the X direction is referred to as the Y direction (horizontal-vertical direction).

[0022] The heat exchanger 1000 of the outdoor unit 200 has a lower header 1100, a refrigerant inlet / outlet pipe 1200, a row header 1300, a plurality of heat transfer tubes 1400, and a plurality of corrugated fins 1500. The lower header 1100 and the refrigerant inlet / outlet pipe 1200 have lower headers 1100A and 1100B, and refrigerant inlet / outlet pipes 1200A and 1200B, respectively.

[0023] In the heat exchanger 1000 according to the first embodiment, for example, a pair of headers, consisting of two lower headers 1100 and a row-transfer header 1300, are arranged above and below in the Z direction. For example, in the case of a top-flow outdoor unit 200, devices such as the compressor 210 are installed in the lower portion of the outdoor unit 200. In such a case, due to piping connections and the like, the row-transfer header 1300 is located on the upper side, and the two lower headers 1100 are located below the row-transfer header 1300.

[0024] A plurality of heat transfer tubes 1400 are arranged in multiple rows along the Y direction between the two lower headers 1100 and the row-transfer headers 1300. As will be described later, the heat transfer tubes 1400 in the first embodiment have a flattened cross section. Here, a group of a plurality of heat transfer tubes 1400 is arranged in two rows, with the flat surfaces facing each other and perpendicular to the lower headers 1100 and the row-transfer headers 1300 and parallel to each other. The group of heat transfer tubes 1400 in one row is connected to one lower header 1100. Here, an example in which the heat transfer tubes 1400 are arranged in two rows will be described, but the present invention can also be applied to a heat exchanger 1000 in which the heat transfer tubes 1400 are arranged in multiple rows of three or more rows.

[0025] Each lower header 1100 is connected to other devices constituting the refrigeration cycle system and includes header pipes 1110 through which a refrigerant, a fluid serving as a heat exchange medium, flows in and out and through which the refrigerant branches or merges. When the heat exchanger 1000 in the first embodiment functions as an evaporator, the lower header 1100A serves as a liquid header through which liquid refrigerant (including two-phase gas-liquid refrigerant) passes and branches the refrigerant. The lower header 1100B serves as a gas header through which gas refrigerant passes and merges the refrigerant. Each lower header 1100 is connected to refrigerant inlet / outlet pipes 1200 (refrigerant inlet / outlet pipes 1200A and 1200B). At one end of the lower header 1100 in the Y direction, the header pipes 1110 include an unconnected region 1101, where a heat transfer tube 1400 (described later) is not inserted and connected. In the first embodiment, the refrigerant inlet / outlet pipe 1200 is a pipe whose one end connects to the lower header 1100 on the top surface of the unconnected region 1101 and whose pipe axis extends in the Z direction. The other end of the refrigerant inlet / outlet pipe 1200 is connected to a connecting pipe outside the heat exchanger 1000, through which the refrigerant flows in and out. For example, in the outdoor unit 200, the piping for connecting the device is arranged in a corner that does not serve as an air flow path within the housing housing the heat exchanger 1000. Therefore, the refrigerant inlet / outlet pipe 1200 is arranged in the corner of the housing to match the piping arrangement. By configuring the refrigerant inlet / outlet pipe 1200 to connect to the lower header 1100 on the top surface of the end of the header pipe 1110, it is not necessary to install piping that ensures a sufficient bending radius at the corner of the housing. This eliminates the need to install a large area on the side of the heat exchanger 1000 installed within the housing. The relationship between the lower header 1100 and the refrigerant inlet / outlet pipe 1200 will be described in detail later.

[0026] In addition, the row-to-row header 1300 is a header that acts as a bridge, joining the refrigerant flowing in from a group of heat transfer tubes 1400 in one row and branching it out to a group of heat transfer tubes 1400 in the other row.

[0027] The heat transfer tube 1400 has a flat cross section, with the outer surface on the long side of the flat shape along the depth direction (the air flow direction) being flat, and the outer surface on the short side perpendicular to the long side being curved. The heat transfer tube 1400 of the first embodiment is a multi-hole flat heat transfer tube having a plurality of holes therein that serve as refrigerant flow paths. In the first embodiment, the holes of the heat transfer tube 1400 are formed facing the height direction to serve as flow paths between the lower header 1100 and the row-to-row header 1300. As described above, the heat transfer tubes 1400 are arranged horizontally at equal intervals with their outer surfaces facing each other on their long sides. When manufacturing the heat exchanger 1000 of the first embodiment, each heat transfer tube 1400 is inserted into insertion holes (not shown) in the lower header 1100 and the row-to-row header 1300, and then brazed and joined. A brazing filler metal containing aluminum is used for the brazing. This allows the lower header 1100, the row header 1300, and the inside of each heat transfer tube 1400 to communicate with each other.

[0028] Corrugated fins 1500 are arranged between the opposing flat surfaces of the arranged heat transfer tubes 1400. The corrugated fins 1500 are arranged to increase the heat transfer area between the refrigerant and the outside air. The corrugated fins 1500 are formed by corrugating a plate material and folding it into a zigzag shape with repeated mountain and valley folds, forming a wavy bellows. While the description here assumes the use of corrugated fins 1500, the shape of the fins is not particularly limited, and fins of other shapes may also be used.

[0029] The dashed arrows in Fig. 2 indicate the flow of refrigerant when the heat exchanger 1000 of the first embodiment is used as an evaporator. When the heat exchanger 1000 functions as an evaporator, as in the heat exchanger 1000 of the first embodiment, the flow of refrigerant is parallel to the flow of air. Here, parallel flow refers to a flow in which the refrigerant flows from the heat transfer tubes 1400 in the row that is upstream of the air flow toward the heat transfer tubes 1400 in the row that is downstream of the air flow.

[0030] As shown in FIG. 2 , the refrigerant that passes through the refrigerant piping 300 and enters the outdoor unit 200 flows via the refrigerant inlet / outlet pipe 1200B into the lower header 1100B of the heat exchanger 1000, which is connected to the heat transfer tube 1400 in the row furthest upstream in the air flow. Because the heat exchanger 1000 of the first embodiment has a two-row configuration, the most upstream will hereinafter be referred to as "upstream." The refrigerant that flows into the lower header 1100B of the heat exchanger 1000 is distributed and passes through the heat transfer tube 1400 in the row furthest upstream in the air flow. The heat transfer tube 1400 exchanges heat between the refrigerant passing through the tube and the outside air passing outside the tube. During this process, the refrigerant absorbs heat from the outside air while passing through the heat transfer tube 1400.

[0031] The refrigerant then turns back at the row-to-row header 1300, passes through the heat transfer tubes 1400 in the row that is downstream in the air flow, and exchanges heat, before flowing into and joining the lower header 1100A of the heat exchanger 1000. When three or more rows of heat transfer tubes 1400 are arranged along the air flow, the refrigerant repeats heat exchange by passing through the downstream heat transfer tubes 1400. The gas refrigerant that joins in the lower header 1100A that is furthest downstream in the air flow flows out of the heat exchanger 1000 through the refrigerant inlet / outlet pipe 1200A connected to the lower header 1100A.

[0032] Fig. 3 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to the first embodiment when viewed along the Y direction. Fig. 4 is a diagram illustrating a portion of a cross section of the heat exchanger 1000 according to the first embodiment when viewed along the X direction. As shown in Fig. 3 , the lower header 1100 of the heat exchanger 1000 according to the first embodiment has a header pipe 1110 configured with a first member 1111 and a second member 1112. The first member 1111 is an inverted U-shaped semi-open member that forms the top surface and flat side surfaces of the long, cylindrical header pipe 1110 extending in the Y direction. The second member 1112 is a member that forms the bottom surface of the cylindrical header pipe 1110.

[0033] 4, the cross-sectional area of ​​the lower header 1100 is defined as a header cross-sectional area Ah. The cross-sectional area of ​​the refrigerant inlet / outlet pipe 1200 is defined as an inlet / outlet pipe cross-sectional area Ap. In this case, the ratio of the header cross-sectional area Ah to the inlet / outlet pipe cross-sectional area Ap in the heat exchanger 1000 of the first embodiment is defined as a cross-sectional area ratio R = Ap / Ah.

[0034] 5 is a diagram showing the relationship between the cross-sectional area ratio R and heat exchange performance according to the first embodiment. The heat exchange performance is expressed, for example, by the amount of energy supplied, such as heat, relative to the temperature change of the refrigerant. As shown in FIG. 5, when the cross-sectional area ratio R is within the range of 0.1<R<0.5, the heat exchange performance is higher than when the cross-sectional area ratio R is within other ranges.

[0035] For example, when the cross-sectional area ratio R is low, the inlet / outlet pipe cross-sectional area Ap is basically small. When the inlet / outlet pipe cross-sectional area Ap is small, the pressure loss in the refrigerant inlet / outlet pipe 1200 increases. This makes it difficult for the refrigerant to flow out of the lower header 1100. Therefore, the lower header 1100 and the refrigerant inlet / outlet pipe 1200 are configured so that the cross-sectional area ratio R is greater than 0.1.

[0036] On the other hand, when the cross-sectional area ratio R is high, the inlet / outlet pipe cross-sectional area Ap is basically large. When the inlet / outlet pipe cross-sectional area Ap is large, the flow velocity in the refrigerant inlet / outlet pipe 1200 becomes slow. As a result, refrigerating machine oil is more likely to flow back from the refrigerant inlet / outlet pipe 1200.

[0037] As described above, according to the first embodiment, the lower header 1100 and the refrigerant inlet / outlet pipes 1200 are configured so that the cross-sectional area ratio R between the header cross-sectional area Ah and the inlet / outlet pipe cross-sectional area Ap satisfies the relationship 0.1 < R < 0.5. This allows refrigerating machine oil to be efficiently discharged from the lower header 1100, and prevents refrigerating machine oil from accumulating in the lower header 1100.

[0038] For example, even when the flow rate of refrigerant circulating through the refrigerant circuit is low, it is possible to prevent refrigerant oil from flowing back due to the influence of gravity in the refrigerant inlet / outlet pipe 1200. Furthermore, because less refrigerant oil remains in the lower header 1100, it is possible to prevent the compressor 210 from running out of refrigerant oil. This makes it possible to prevent performance degradation and damage to the compressor 210. Furthermore, because the amount of refrigerant oil in the refrigerant circuit can be reduced, it is possible to reduce costs.

[0039] Here, the range of cross-sectional area ratio R shown in embodiment 1 is a configuration that is most effective when applied to the lower header 1100B on the refrigerant outflow side, which becomes a gas header when functioning as an evaporator, but it can also be applied to the lower header 1100A on the refrigerant inflow side.

[0040] Embodiment 2. Fig. 6 is a diagram showing a portion of a cross section of a heat exchanger 1000 according to embodiment 2 when viewed along the Y direction. Fig. 7 is a diagram showing a portion of a cross section of a heat exchanger 1000 according to embodiment 2 when viewed along the X direction. In Figs. 6 and 7, components and the like having the same reference numerals as Figs. 3 and 4 perform the same functions and operations as those described in embodiment 1. Although not particularly limited, Figs. 6 and 7 show the configuration of a lower header 1100A that serves as a gas header. However, the present invention is not limited to this. The configuration can also be applied to a lower header 1100B.

[0041] 6 and 7 , the lower header 1100 in the heat exchanger 1000 of the second embodiment is a refrigerant distributor with a double structure including a header pipe 1110 serving as an outer pipe and an inner pipe 1120. The lower header 1100 also has a partition plate 1130. As in the first embodiment, the header pipe 1110 is a pipe formed by combining a first member 1111 and a second member 1112. The partition plate 1130 forms a wall between the inner pipe 1120 and the header pipe 1110 that divides the space within the header pipe 1110 into a second space 1150 that communicates with the heat transfer pipe 1400 and a third space 1160 that communicates with the refrigerant inlet / outlet pipe 1200.

[0042] On the other hand, the inner pipe 1120 is a long pipe that is installed inside the header pipe 1110 along the header pipe 1110. The inner pipe 1120 serves as a wall that divides the space inside the header pipe 1110 into a first space 1140 and a second space 1150. Here, in the lower header 1100 of the second embodiment, the dimensional center of the inner pipe 1120 is located lower than the dimensional center of the header pipe 1110 in the height direction. By positioning the inner pipe 1120 in a space located lower inside the header pipe 1110, it is possible to reduce the area where liquid refrigerant is likely to stagnate.

[0043] The inner pipe 1120 has an orifice 1121 serving as a refrigerant inlet / outlet hole. Here, the orifice 1121 in the second embodiment is not located directly below the inner pipe 1120 but is located diagonally below the inner pipe 1120 in a direction that sprays the gas-liquid two-phase refrigerant onto the downwind side of the air passing through the heat exchanger 1000.

[0044] For example, the refrigerant that flows from the refrigerant inlet / outlet pipe 1200 into the header pipe 1110 passes through the third space 1160 and flows into the first space 1140 in the inner pipe 1120. The refrigerant that flows out from the orifice 1121 is ejected into the second space 1150 of the header pipe 1110 and flows into the heat transfer pipe 1400. The refrigerant that flows from the heat transfer pipe 1400 into the header pipe 1110 of the lower header 1100 passes through the second space 1150, flows from the orifice 1121 into the first space 1140 in the inner pipe 1120, passes through the third space 1160, and flows out of the refrigerant inlet / outlet pipe 1200.

[0045] In the lower header 1100 in the second embodiment, for example, when gas-liquid two-phase refrigerant flows from the refrigerant inlet / outlet pipe 1200 into the header pipe 1110, the gas-liquid two-phase refrigerant flows into the third space 1160 in the header pipe 1110 and then passes through the first space 1140. Therefore, the gas refrigerant and liquid refrigerant of the gas-liquid two-phase refrigerant are mixed in the third space 1160 and pass through the first space 1140. The gas-liquid two-phase refrigerant is also agitated when it passes through the first space 1140 and flows out from the orifice 1121 into the second space 1150 between the inner pipe 1120 and the header pipe 1110. Therefore, the liquid refrigerant and the gas refrigerant become nearly homogeneous. By making the refrigerant flow ratio of the refrigerant passing through the multiple heat transfer pipes 1400 more uniform, the heat exchange performance of the heat exchanger 1000 is improved.

[0046] Furthermore, the heat transfer tube 1400 has multiple flow paths along the X direction, which is the direction in which air passes. By ejecting the gas-liquid two-phase refrigerant to the downwind side from orifices 1121 provided diagonally below the inner tube 1120, a gas-rich refrigerant having a higher proportion of gas refrigerant components in the gas-liquid two-phase refrigerant is supplied to the downwind flow path of the heat transfer tube 1400. On the other hand, a liquid-rich refrigerant having a higher proportion of liquid refrigerant components in the gas-liquid two-phase refrigerant is supplied to the upwind flow path of the heat transfer tube 1400. Therefore, more liquid refrigerant can be distributed to the upwind side where the temperature difference between the refrigerant and the air is greater, thereby improving heat transfer performance.

[0047] Embodiment 3 Fig. 8 is a diagram showing a part of a cross section of a heat exchanger 1000 according to embodiment 3 when viewed along the X direction. In Fig. 8, components and the like having the same reference numerals as those in Figs. 4 and 7 perform the same functions and operations as those described in embodiment 1 and embodiment 2.

[0048] 8, the lower header 1100 in the heat exchanger 1000 of the third embodiment has an oil orifice 1131 below the partition plate 1130. The oil orifice 1131 is a communication hole that connects the second space 1150 and the third space 1160 and allows refrigeration oil to pass through.

[0049] As described above, refrigeration oil has a higher specific gravity than refrigerant and therefore tends to accumulate in the lower portion of lower header 1100. For this reason, in heat exchanger 1000 according to the third embodiment, oil orifice 1131 is provided in the lower portion of partition plate 1130. Therefore, in the flow of refrigerant, refrigeration oil that flows in from refrigerant inlet / outlet pipe 1200 and accumulates in third space 1160 can be made to flow out to second space 1150. Furthermore, refrigeration oil that flows in from heat transfer pipe 1400 and accumulates in second space 1150 can be made to flow out to third space 1160. Here, if the opening area of ​​oil orifice 1131 is large, refrigeration oil tends to flow out to third space 1160. On the other hand, when lower header 1100 functions as a condenser, the effect of separating second space 1150 and third space 1160 with partition plate 1130 cannot be achieved. For this reason, the size of the oil orifice 1131 is adjusted appropriately.

[0050] 9 to 11 are diagrams illustrating the shape of the oil orifice 1131 according to the third embodiment. The shape of the oil orifice 1131 is not particularly limited. For example, as shown in FIG. 9, the oil orifice 1131 may be semicircular. As shown in FIG. 10, the oil orifice 1131 may be rectangular. Furthermore, as shown in FIG. 11, the oil orifice 1131 may be triangular.

[0051] Embodiment 4 Fig. 12 is a diagram showing a part of a cross section of a heat exchanger 1000 according to embodiment 4 when viewed along the X direction. In Fig. 12, components and the like having the same reference numerals as those in Fig. 6 and the like perform the same functions and operations as those described in embodiments 1 to 3.

[0052] 12 , the heat exchanger 1000 of the fourth embodiment has a first refrigerant inlet / outlet pipe 1210 and a second refrigerant inlet / outlet pipe 1220. The first refrigerant inlet / outlet pipe 1210 is connected to the lower header 1100 at the top surface of the uninserted portion and extends in the Z direction, with its pipe axis being the height direction. On the other hand, the second refrigerant inlet / outlet pipe 1220 is a pipe extending in the X direction, with its pipe axis being the horizontal direction. The second refrigerant inlet / outlet pipe 1220 is bent in the Z direction midway and connected to the first refrigerant inlet / outlet pipe 1210. Therefore, when refrigerant flows out of the lower header 1100, the refrigerant that has passed through the second refrigerant inlet / outlet pipe 1220 merges with the refrigerant passing through the first refrigerant inlet / outlet pipe 1210. Furthermore, the refrigerant branching from the first refrigerant inlet / outlet pipe 1210 to the second refrigerant inlet / outlet pipe 1220 merges with the refrigerant that has passed through the first refrigerant inlet / outlet pipe 1210 in the third space 1160 inside the header pipe 1110 .

[0053] The heat exchanger 1000 in the fourth embodiment has, in addition to the first refrigerant inlet / outlet pipe 1210 whose pipe axis extends in the Z direction, a second refrigerant inlet / outlet pipe 1220 whose pipe axis is horizontal and extends in the Y direction along the direction of the lower header 1100. Therefore, refrigeration oil, which has a larger specific gravity than the refrigerant, is prevented from accumulating in the lower header 1100, and can flow out from the second refrigerant inlet / outlet pipe 1220.

[0054] Embodiment 5 Fig. 13 is a diagram showing a part of a cross section of a heat exchanger 1000 according to embodiment 5 when viewed along the X direction. In Fig. 13, components and the like having the same reference numerals as those in Fig. 12 and the like perform the same functions and operations as those described in embodiments 1 to 4.

[0055] In the heat exchanger 1000 of the fourth embodiment, the second refrigerant inlet / outlet pipe 1220 is connected to the first refrigerant inlet / outlet pipe 1210 extending in the Z direction. In the heat exchanger 1000 of the fifth embodiment, the second refrigerant inlet / outlet pipe 1220 is connected to the first refrigerant inlet / outlet pipe 1210 whose pipe axis is bent in the horizontal direction midway.

[0056] For this reason, the heat exchanger 1000 in the fifth embodiment has the second refrigerant inlet / outlet pipe 1220 extending in the Y direction along the direction of the lower header 1100, thereby suppressing stagnation of refrigerating machine oil in the lower header 1100 and allowing it to flow out from the second refrigerant inlet / outlet pipe 1220. Furthermore, the first refrigerant inlet / outlet pipe 1210 has its pipe axis bent horizontally midway, thereby preventing backflow of refrigerating machine oil due to gravity.

[0057] Sixth Embodiment Fig. 14 is a diagram illustrating the arrangement of the outdoor heat exchanger 230 in the outdoor unit 200 according to the sixth embodiment. Fig. 14 shows the arrangement in the housing 201 when the outdoor unit 200 is viewed from above along the height direction. The row transfer header 1300 is not shown in Fig. 14. In Fig. 14, white arrows indicate the flow of air, and black arrows indicate the flow of refrigerant when the heat exchanger 1000 serving as the outdoor heat exchanger 230 functions as an evaporator.

[0058] The outdoor unit 200 of the sixth embodiment is a side-flow type unit having an outlet (not shown) for the outdoor fan 250 on a side surface of the housing 201. In the outdoor unit 200, the rotation axis of the outdoor fan 250 is arranged horizontally, and air flows into the housing 201 from one longitudinal side surface of the housing 201 and is blown out toward the opposite side surface. The outdoor unit 200 of the sixth embodiment has two heat exchangers 1000, which serve as the outdoor heat exchanger 230, arranged in an L-shape on one longitudinal side surface and one lateral side surface of the housing 201. While not particularly limited, of the two heat exchangers 1000, for example, the heat exchanger 1000 arranged on the lateral side surface may be a subcooling heat exchanger that subcools the refrigerant when the outdoor heat exchanger 230 functions as a condenser. Alternatively, a portion of one heat exchanger 1000 may be bent to form an L-shape.

[0059] Seventh Embodiment. FIG. 15 is a diagram illustrating the arrangement of the outdoor heat exchanger 230 in the outdoor unit 200 according to the seventh embodiment. FIG. 15 illustrates the arrangement within the housing 201 when the outdoor unit 200 is viewed from above along the height direction. The row transfer header 1300 is not illustrated in FIG. 15 . In FIG. 15 , white arrows indicate the flow of air, and black arrows indicate the flow of refrigerant when the heat exchanger 1000 serving as the outdoor heat exchanger 230 functions as an evaporator. The outdoor unit 200 according to the seventh embodiment is a top-flow type unit having an outlet (not shown) for the outdoor fan 250 at the center of the top of the housing 201. In the outdoor unit 200, the rotation axis of the outdoor fan 250 is vertically arranged, and air flows into the housing 201 from the side and is blown out toward the top.

[0060] In the outdoor unit 200 according to the seventh embodiment, three heat exchangers 1000 serving as the outdoor heat exchanger 230 are arranged in a U-shape so as to surround the outdoor fan 250 at an upper position on the side surface of the housing 201. Although not particularly limited, for example, one of the three heat exchangers 1000 may be a supercooling heat exchanger that supercools the refrigerant when the outdoor heat exchanger 230 functions as a condenser.

[0061] In the first embodiment described above, the heat exchanger 1000 is used in the outdoor heat exchanger 230 of the outdoor unit 200, but this is not limiting. The heat exchanger 1000 may be used in the indoor heat exchanger 110 of the indoor unit 100, or may be used in both the outdoor heat exchanger 230 and the indoor heat exchanger 110.

[0062] In the above-described embodiments, the heat exchanger 1000 is configured such that the heat transfer tubes 1400 are arranged in rows and multiple rows of the heat transfer tubes 1400 are connected between two lower headers 1100 and a row-to-row header 1300, but the heat exchanger 1000 may also have a single row of heat transfer tubes 1400.

[0063] Furthermore, in the above-mentioned embodiment 1 and the like, the heat exchanger 1000 has been described as being applied to an air conditioning system, but it can also be applied to other refrigeration cycle devices, such as a refrigerator, a freezer, or a hot water supply system.

[0064] 100 Indoor unit, 110 Indoor heat exchanger, 120 Expansion valve, 130 Indoor fan, 200 Outdoor unit, 201 Housing, 210 Compressor, 220 Four-way valve, 230 Outdoor heat exchanger, 240 Accumulator, 250 Outdoor fan, 300 Refrigerant piping, 1000 Heat exchanger, 1100, 1100A, 1100B Lower header, 1101 Unconnected area, 1110 Header pipe, 1111 First member, 1112 Second member, 1120 Inner pipe, 1121 Orifice, 1130 Partition plate, 1131 Oil orifice, 1140 First space, 1150 Second space, 1160 Third space, 1200, 1200A, 1200B Refrigerant inlet / outlet pipe, 1210 First refrigerant inlet / outlet pipe, 1220 second refrigerant inlet / outlet pipe, 1300 row header, 1400 heat transfer tube, 1500 corrugated fin.

Claims

1. A heat exchanger comprising: a pair of headers spaced apart from each other and arranged in the height direction, through which a refrigerant passes inside a cylindrical tube; a plurality of heat transfer tubes arranged in a plurality of stages at intervals in the longitudinal direction of the pair of headers and connected to each other, having a flow path inside through which the refrigerant flows; and a first refrigerant inlet / outlet tube connected to a lower header located on the lower side of the pair of headers in the same direction as the flow path of the plurality of heat transfer tubes, through which the refrigerant flows in and out in an external connection pipe. When a cross-sectional area ratio R of the inlet / outlet pipe cross-sectional area Ap of the first refrigerant inlet / outlet tube to the header cross-sectional area Ah of the lower header is defined as R = Ap / Ah, the cross-sectional area ratio R is within a range of 0.1 < R < 0.

5.

2. The heat exchanger according to claim 1, wherein the lower header includes: a header tube serving as an outer tube to which the plurality of heat transfer tubes are connected; an inner tube installed inside the header tube, serving as a wall that divides the inside of the header tube into a first space where the heat transfer tubes are not connected and a second space where the heat transfer tubes are connected; and a partition plate serving as a wall that divides the inside of the header tube into the second space where the heat transfer tubes are connected and a third space where the first refrigerant inlet / outlet tube is connected. The inner tube has a plurality of orifices that communicate the first space and the second space.

3. The heat exchanger according to claim 2, wherein the partition plate has an oil orifice at the lower part that communicates the second space and the third space.

4. The heat exchanger according to any one of claims 1 to 3, further comprising a second refrigerant inlet / outlet tube having one end connected to the lower header in the longitudinal direction, through which the refrigerant flows in and out in the connection pipe. The second refrigerant inlet / outlet tube has the other end connected to the first refrigerant inlet / outlet tube extending in the height direction.

5. The heat exchanger according to any one of claims 1 to 3, further comprising a second refrigerant inlet / outlet tube having one end connected to the lower header in the longitudinal direction, through which the refrigerant flows in and out in the connection pipe. The second refrigerant inlet / outlet tube has the other end connected to the first refrigerant inlet / outlet tube bent in the horizontal direction.

6. An outdoor unit having the heat exchanger according to any one of claims 1 to 5 as an outdoor heat exchanger.

7. A refrigeration cycle device having the outdoor unit according to claim 6.

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