Air conditioning apparatus

Abstract

This outdoor unit has a compressor, an outdoor heat exchanger, a blower fan, and an electrical component box. The outdoor heat exchanger has a plurality of refrigerant channels that include: a plurality of heat transfer tube groups; and a plurality of flow-dividing tubes which connect the plurality of heat transfer tube groups and a refrigerant pipe. The outdoor unit housing has a partition plate that partitions a machine room and a blower room. The electrical component box is disposed between the outdoor heat exchanger and the blower fan. When, among the plurality of refrigerant channels, a refrigerant channel that includes a heat transfer tube group where airflow is obstructed by the electrical component box is defined as a first refrigerant channel and a refrigerant channel other than the first refrigerant channel is defined as a second refrigerant channel, the first refrigerant channel and the second refrigerant channel are formed such that the amount of a refrigerant flowing through the first refrigerant channel per unit time is smaller than the amount of a refrigerant flowing through the second refrigerant channel per unit time.

Description

Air conditioner

[0001] The present invention relates to an air conditioner including an outdoor unit and an indoor unit.

[0002] In recent years, in consideration of reducing environmental impact, the use of natural refrigerants with a low global warming potential (GWP: Global Warming Potential) has been started. Examples of natural refrigerants include flammable refrigerants such as propane (R290).

[0003] Further, the interior of the housing of the outdoor unit is partitioned into a machine room where a compressor is disposed and a blower room (heat exchange room) where an outdoor heat exchanger and a blower fan are disposed. Further, inside the housing of the outdoor unit, an electrical component box storing a control board, a power supply board, etc. for controlling the drive of the compressor and the blower fan is disposed.

[0004] In the machine room, since there are many locations where refrigerant pipes are connected to devices such as compressors, the possibility of refrigerant leakage is higher than in the blower room. When using a refrigerant with a specific gravity greater than that of air, such as propane, the leaked refrigerant stays in the lower part of the machine room. Therefore, in order to prevent the leaked refrigerant from coming into contact with the electrical component box and igniting, the electrical component box is preferably disposed above the blower room.

[0005] On the other hand, when the electrical component box is disposed in the blower room, the electrical component box is disposed between the outdoor heat exchanger and the blower fan in the air flow path (the air path connecting the suction port and the blowout port) in the blower room. In this case, the electrical component box becomes a resistance to air flow, and there may be a path in which the ventilation volume decreases among the plurality of paths (refrigerant flow paths) of the outdoor heat exchanger. In the path where the ventilation volume decreases, the ventilation volume is insufficient with respect to the amount of refrigerant flowing through the path. When the outdoor heat exchanger functions as a condenser, the refrigerant may not be sufficiently condensed, or when the outdoor heat exchanger functions as an evaporator, the refrigerant may not be sufficiently evaporated, and there is a possibility that the required heat exchange amount between the refrigerant and air cannot be obtained.

[0006] To solve these problems, for example, Patent Document 1 discloses an air conditioning system in which an electrical component box is placed above the blower room, and an inclined portion is provided on the bottom plate of the electrical component box so that the upstream end of the airflow flowing through the ventilation passage is positioned above the downstream end of the airflow, thereby allowing the airflow that has passed through a heat exchanger located upstream of the electrical component box to be smoothly guided to an outlet located downstream of the electrical component box.

[0007] Patent No. 7561991

[0008] However, if a slanted section is provided on the bottom plate of the electrical component box, as described in Patent Document 1, to prevent the creation of airflow paths that reduce the amount of airflow in the outdoor heat exchanger, the volume of the electrical component box decreases, thus limiting the size of the control board and power supply board housed in the electrical component box. Furthermore, if the height, width, and depth dimensions of the electrical component box are increased to compensate for the volume reduction caused by the formation of the slanted section, the outdoor unit casing becomes larger, which is problematic.

[0009] In view of the above circumstances, the object of the present invention is to provide an air conditioning system that can secure the required amount of heat exchange between refrigerant and air in the outdoor heat exchanger while suppressing a reduction in the volume of the electrical components box or an increase in the size of the outdoor unit.

[0010] An air conditioning system according to one embodiment of the present invention is an air conditioning system equipped with a refrigerant circuit having an outdoor unit, an indoor unit, and refrigerant piping connecting the outdoor unit and the indoor unit. The outdoor unit has a compressor, an outdoor heat exchanger, a blower fan, an electrical box housing a control board that controls the driving of the compressor and the blower fan, and an outdoor unit housing that houses the compressor, the outdoor heat exchanger, the blower fan, and the electrical box. The outdoor heat exchanger has a plurality of refrigerant flow paths, including a plurality of heat transfer tube groups and a plurality of branch pipes that connect the plurality of heat transfer tube groups and the refrigerant piping. The plurality of heat transfer tube groups are formed by connecting a plurality of heat transfer tubes arranged in a vertical direction. The outdoor unit housing includes a partition plate, an intake port for drawing air from outside the outdoor unit into the blower room by the rotation of the blower fan, and an outlet port for blowing air from the blower room to outside the outdoor unit by the rotation of the blower fan. The partition plate divides the unit into a machine room where the compressor is located and a blower room where the outdoor heat exchanger, the blower fan, and at least a part of the electrical component box are located. The electrical component box is located between the outdoor heat exchanger and the blower fan in an air passage formed between the intake port and the outlet port. When one of the plurality of refrigerant passages is designated as the first refrigerant passage, which includes a group of heat transfer tubes whose ventilation is obstructed by the electrical component box, and the other refrigerant passages are designated as the second refrigerant passages, the first and second refrigerant passages are formed such that the amount of refrigerant flowing per unit time through the first refrigerant passage is less than the amount of refrigerant flowing per unit time through the second refrigerant passage.

[0011] This makes it possible to ensure the required amount of heat exchange between refrigerant and air in the outdoor heat exchanger while suppressing a reduction in the volume of the electrical components box or an increase in the size of the outdoor unit.

[0012] The flow resistance of the refrigerant flowing through the first refrigerant flow path may be greater than the flow resistance of the refrigerant flowing through the second refrigerant flow path.

[0013] In this case, the cross-sectional area of ​​the heat transfer tube forming the first refrigerant flow path may be smaller than the cross-sectional area of ​​the heat transfer tube forming the second refrigerant flow path.

[0014] Alternatively, the cross-sectional area of ​​the branch pipe forming the first refrigerant flow path may be smaller than the cross-sectional area of ​​the branch pipe forming the second refrigerant flow path.

[0015] The plurality of heat transfer tube groups may include a first heat transfer tube group in which a plurality of heat transfer tubes forming the first refrigerant flow path are connected in series, and a second heat transfer tube group in which a plurality of heat transfer tubes forming at least a part of the second refrigerant flow path are connected in series, and the number of heat transfer tubes connected in the first heat transfer tube group may be greater than the number of heat transfer tubes connected in the second heat transfer tube group.

[0016] The refrigerant circuit may be filled with a flammable refrigerant that has a higher specific gravity than air in its gaseous state, and the electrical equipment box may be located above the blower room.

[0017] The blower fan may have a rotating shaft and an impeller attached to the rotating shaft. When viewed from the left-right direction of the outdoor unit housing, if a straight line is defined as the shortest distance connecting the top of the outdoor heat exchanger and the top of the rotational trajectory of the impeller when the blower fan is rotating, at least a part of the electrical component box may be positioned on the outdoor heat exchanger side of the straight line.

[0018] The outdoor unit may further include a flow divider that divides the refrigerant from the refrigerant piping into the first refrigerant flow path and the second refrigerant flow path when the outdoor heat exchanger functions as an evaporator. The plurality of flow dividers may include a first flow divider connected to the flow divider and forming the first refrigerant flow path, and a second flow divider connected to the flow divider and forming the second refrigerant flow path, wherein the length of the first flow divider may be longer than the length of the second flow divider.

[0019] The electrical components box may be positioned such that, when viewed from above the outdoor unit housing, the length of the portion of the electrical components box located on the blower room side from the partition plate is more than half the length of the outdoor heat exchanger located on the blower room side from the partition plate.

[0020] The second refrigerant flow path may include a plurality of refrigerant flow paths, each with a different amount of refrigerant flowing per unit time, corresponding to the difference in the amount of air received by the rotation of the blower fan.

[0021] According to the present invention, it is possible to secure the required amount of heat exchange between refrigerant and air in the outdoor heat exchanger while suppressing a reduction in the volume of the electrical component box or an increase in the size of the outdoor unit.

[0022] This is a refrigerant circuit diagram showing one example configuration of the air conditioning system of this embodiment. This is a perspective view showing the overall configuration of the outdoor unit in the above air conditioning system. This is a perspective view showing the internal structure of the above outdoor unit. This is a side view showing the internal structure of the fan chamber in the above outdoor unit. This is a side view of the outdoor heat exchanger in the above outdoor unit. This is a schematic diagram showing an example of the flow resistance of each refrigerant flow path in the above outdoor heat exchanger. This is a schematic diagram showing the relationship between the outdoor heat exchanger, the blower fan and the electrical equipment box when the above outdoor heat exchanger is viewed from above its housing.

[0023] Embodiments of the present invention will be described below with reference to the drawings.

[0024] [Air Conditioning System] Figure 1 is a refrigerant circuit diagram showing one example configuration of the air conditioning system 100 of this embodiment. First, the outline of the air conditioning system 100 will be described with reference to Figure 1.

[0025] The air conditioning system 100 has an outdoor unit 1, an indoor unit 2, and a refrigerant circuit 110 that includes a plurality of refrigerant pipes 9 (gas pipes 92G, liquid pipes 92L) connecting the outdoor unit 1 and the indoor unit 2. The refrigerant circuit 110 is filled with a flammable refrigerant (for example, propane) that has a specific gravity greater than air in its gaseous state.

[0026] The outdoor unit 1 includes a compressor 3, a four-way valve 4, an outdoor heat exchanger 5, an outdoor fan 5F, an accumulator 6, an expansion valve 7, and an electrical component box 14, which will be described later. The indoor unit 2 includes an indoor heat exchanger 8 and an indoor fan 8F. The expansion valve 7 may be installed in the indoor unit 2.

[0027] For example, during cooling operation, the four-way valve 4 is switched, causing the refrigerant to flow through the refrigerant circuit 110 as shown by the solid arrow in Figure 1. The high-temperature, high-pressure refrigerant discharged from the compressor 3 flows through the four-way valve 4 into the outdoor heat exchanger 5, which functions as a condenser. The high-temperature, high-pressure gaseous refrigerant that has exchanged heat with the outside air in the outdoor heat exchanger 5 condenses and liquefies. Subsequently, the high-temperature, high-pressure liquid refrigerant is depressurized by passing through the expansion valve 7, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which flows into the indoor heat exchanger 8, which functions as an evaporator. In the indoor heat exchanger 8, the refrigerant that has exchanged heat with the air vaporizes and is then drawn into the compressor 21 via the four-way valve 4 and the accumulator 6.

[0028] On the other hand, during heating operation, the four-way valve 4 is switched, allowing the refrigerant to flow through the refrigerant circuit 110 as shown by the dashed arrow in Figure 1. The high-temperature, high-pressure refrigerant (gas refrigerant) discharged from the compressor 3 flows into the indoor heat exchanger 8, which functions as a condenser, via the four-way valve 4. The high-temperature, high-pressure refrigerant that has exchanged heat with the air in the indoor heat exchanger 8 condenses and liquefies. Subsequently, the high-temperature, high-pressure liquid refrigerant is depressurized by passing through the expansion valve 7 to become a low-temperature, low-pressure gas-liquid two-phase refrigerant, which flows into the outdoor heat exchanger 5, which functions as an evaporator. After the refrigerant that has exchanged heat with the outside air in the outdoor heat exchanger 5 vaporizes, it is drawn into the compressor 3 via the four-way valve 4 and the accumulator 6.

[0029] The outdoor fan 5F is, for example, a blower fan that generates airflow in accordance with the rotation of an impeller, and in this embodiment comprises a motor M and an impeller P attached to the rotation shaft Ma of the motor M. The indoor fan 8F is, for example, a cross-flow fan.

[0030] The outdoor fan 5F is positioned near the outdoor heat exchanger 5 to form a flow of outside air passing through the outdoor heat exchanger 5, and promotes heat exchange between the refrigerant and air in the outdoor heat exchanger 5, which functions as a condenser during cooling operation and as an evaporator during heating operation. The indoor fan 8F is positioned near the indoor heat exchanger 8 to form a flow of indoor air passing through the indoor heat exchanger 8, and promotes heat exchange between the refrigerant and air in the indoor heat exchanger 8, which functions as an evaporator during cooling operation and as a condenser during heating operation.

[0031] One of the refrigerant inlets and outlets of the outdoor heat exchanger 5 is connected to the four-way valve 4 by the outdoor unit gas pipe 91G. The outdoor unit gas pipe 91G is part of the refrigerant piping 9 that connects to the gas pipe 92G via the four-way valve 4, the compressor 3, and the accumulator 6.

[0032] The other refrigerant inlet / outlet of the outdoor heat exchanger 5 is connected to the expansion valve 7 by the outdoor unit liquid pipe 91L. The outdoor unit liquid pipe 91L is part of the refrigerant piping 9 that connects to the liquid pipe 92L via the expansion valve 7. As will be described later, the outdoor heat exchanger 5 has a plurality of heat transfer tube groups formed by connecting a plurality of heat transfer tubes arranged in a vertical direction, and a plurality of diversion pipes 23 that connect the plurality of heat transfer tube groups to the outdoor unit liquid pipe 91L. Each diversion pipe 23 is connected to the outdoor unit liquid pipe 91L via a diversion device 32.

[0033] During heating operation, when the outdoor heat exchanger 5 functions as an evaporator, the gaseous two-phase refrigerant flowing out from the expansion valve 7 is divided into each of the diversion pipes 23 by the diversion device 32 and flows into the outdoor heat exchanger 5. During cooling operation, when the outdoor heat exchanger 5 functions as a condenser, the refrigerant flowing out from the outdoor heat exchanger 5 into each of the diversion pipes 23 is merged by the diversion device 32 and flows into the expansion valve 7 through the outdoor unit liquid pipe 91L.

[0034] [Outdoor Unit] Next, the details of the outdoor unit 1 of this embodiment will be described. Figure 2 is a perspective view showing the overall configuration of the outdoor unit 1, and Figure 3 is a perspective view showing the internal structure of the outdoor unit 1.

[0035] The outdoor unit 1 includes a metal housing 10 (outdoor unit housing) that forms the outer casing of the outdoor unit 1. The housing 10 is formed in a rectangular parallelepiped shape having a top plate portion 10T, a bottom plate portion 10B, a front panel portion 10F, and a pair of side panel portions 10S1 and 10S2. The front panel portion 10F corresponds to the front part of the housing 10.

[0036] As shown in Figure 3, the housing 10 has a partition plate 13 that divides the inside of the housing 10 into a machine room 11 and a blower room 12. The compressor 3 and accumulator 6 are located at the bottom (bottom plate portion 10B) of the machine room 11. The outdoor heat exchanger 5 and outdoor fan 5F are located in the blower room 12.

[0037] On the rear side of the housing 10, there is an intake port 101 (see Figure 3) for drawing air from outside the outdoor unit 1 into the blower chamber 12 by the rotation of the outdoor fan. On the front side of the housing 10, there is an outlet port 102 (see Figure 2) for blowing air from the blower chamber 12 to the outside of the outdoor unit 1 by the rotation of the outdoor fan 5F.

[0038] Inside the housing 10 is an electrical components box 14, which houses a control board that controls the operation of the compressor 3 and the outdoor fan 5F. At least a portion of the electrical components box 14 is located in the blower room 12. The electrical components box 14 is located between the outdoor heat exchanger 5 and the outdoor fan 5F in the air passage 20 (the air passage connecting the air passage 101 and the air passage 102, see Figure 4) formed between the intake port 101 and the outlet port 102.

[0039] As shown in Figure 3, the outdoor heat exchanger 5 is an L-shaped heat exchanger having a main body portion 5a positioned facing the intake port 101 of the housing 10 and a side portion 5b facing the side portion 10S2. Although not shown in the figure, an intake port is also provided on the side portion 10S2. The outdoor heat exchanger 5 is configured as a so-called cross-fin tube type, in which a plurality of heat transfer tubes 24 parallel to the left-right direction of the housing 10 and a plurality of heat dissipation plates 33 perpendicular to the heat transfer tubes 24 (parallel to the up-down direction of the housing 10) intersect at right angles to each other (see Figure 5). Each heat transfer tube 24 forms a path in the outdoor heat exchanger 5, which is a refrigerant flow path.

[0040] In this embodiment, the electrical component box 14 is positioned above the machine room 11 and above the blower room 12, straddling the partition plate 13. The electrical component box 14 is a rectangular parallelepiped box, and its bottom is fixed to the top of the motor mounting base 15, which is positioned vertically from the bottom (bottom plate portion 10B) of the blower room 12 and to which the motor M of the outdoor fan 5F is mounted (see Figure 4).

[0041] Figure 4 is a side view showing the internal structure of the blower room 13. The lower end of the motor mounting base 15 is fixed to the bottom of the blower room 12, and the upper end of the motor mounting base 15 is formed as a support base 16 that supports the bottom of the electrical equipment box 15. A motor M that drives the outdoor fan 5F is fixed to approximately the center of the motor mounting base 15 in the height direction. The outdoor fan 5F sends outdoor air W from the rear side to the front side of the outdoor unit 1 by the rotation of the motor M.

[0042] As shown in Figure 4, when viewed from the left-right direction of the housing 10, if we define a virtual line V as the shortest distance connecting the top of the outdoor heat exchanger 5 and the top of the rotational trajectory of the impeller P (maximum outer diameter of the impeller P) when the blower fan 5F is rotating, then at least a part of the electrical component box 14 is positioned on the outdoor heat exchanger 5 side of the virtual line V. The bottom of the electrical component box 14 has a planar shape parallel to the front-rear and left-right directions, and the upper part of the air passage 20 is blocked by the rear end portion 14e, which is a part of the bottom of the electrical component box 14. In other words, in this embodiment, the rear end portion 14e of the electrical component box 14 is positioned on the outdoor heat exchanger 5 side of the virtual line V. Here, the rear end portion 14e is not limited to a part of the bottom of the electrical component box 14, but also includes parts that protrude downward, such as a heat sink for heat dissipation provided at the bottom of the electrical component box 14.

[0043] In this case, the electrical component box 14 acts as resistance to airflow, which can cause a decrease in the amount of airflow through one of the multiple paths (refrigerant flow paths) of the outdoor heat exchanger 5, specifically a path 5p. The path 5p with reduced airflow corresponds to a path located in the region above the point where the rear end 14e of the electrical component box 14, which is located on the outdoor heat exchanger 5 side of the dashed line V, is projected onto the outdoor heat exchanger 5, as shown in Figure 4. In the path 5p with reduced airflow, the amount of airflow is insufficient relative to the amount of refrigerant flowing through that path 5p. This can result in the refrigerant not condensing sufficiently when the outdoor heat exchanger 5 functions as a condenser, or the refrigerant not evaporating sufficiently when the outdoor heat exchanger 5 functions as an evaporator, potentially preventing the required amount of heat exchange between refrigerant and air from being achieved.

[0044] In order to solve such problems, as described in Patent Document 1 mentioned above, an inclined portion is provided at the bottom of the electrical component box so that the upstream end of the air flow passing through the ventilation path is located above the downstream end of the air flow. By doing so, it is conceivable to guide the air flow that has passed through the heat exchanger arranged on the upstream side of the electrical component box to the air outlet arranged on the downstream side of the electrical component box. However, if an inclined portion is provided on the bottom plate of the electrical component box as described above so as not to create a path where the ventilation volume decreases in the outdoor heat exchanger, the volume of the electrical component box decreases, so the sizes of the control board and the power supply board stored in the electrical component box are limited. Also, if the height dimension, width dimension, depth dimension, etc. of the electrical component box are increased to compensate for the volume reduction of the electrical component box caused by the formation of the inclined portion, there arises a problem that the housing of the outdoor unit becomes large-sized.

[0045] Therefore, in the present embodiment, the outdoor heat exchanger 5 is configured such that it is possible to reduce the adverse influence of the electrical component box 14 arranged in the blower chamber 12 on the heat exchange performance of the outdoor heat exchanger 5 while suppressing the reduction of the volume of the electrical component box 14 or the enlargement of the outdoor unit 1. Hereinafter, the details of the outdoor heat exchanger 5 will be described.

[0046] [Details of Outdoor Heat Exchanger] Fig. 5 is a side view of the outdoor heat exchanger 5 (main body portion 5a). The outdoor heat exchanger 5 has an upper heat exchanger portion 51a and a lower heat exchanger portion 51b having substantially the same configuration, and these upper heat exchanger portion 51a and lower heat exchanger portion 51b are arranged overlapping each other in the vertical direction. The upper heat exchanger portion 51a and the lower heat exchanger portion 51b each have a plurality of heat transfer tubes 24 extending in a direction parallel to the left-right direction of the housing 10 and arranged side by side in the vertical direction.

[0047] The upper heat exchanger portion 51a has, for example, 48 heat transfer tubes 24. Among them, 24 in the upper half are connected to each flow dividing tube 23a1 through connecting portions 34a11, 34a12, 34a13, 3a14 as a group of heat transfer tubes in which 6 heat transfer tubes 24 each connected in series by a U-shaped tube 3 are grouped. Similarly, for the 24 in the lower half, they are connected to each flow dividing tube 23a2 through connecting portions 34a21, 34a22, 34a23, 34a24 as a group of heat transfer tubes in which 6 heat transfer tubes 24 each connected in series by a U-shaped tube 3 are grouped.

[0048] The lower heat exchanger 51b has, for example, 52 heat transfer tubes 24. Six heat transfer tubes 24 each connected in series by a U-shaped tube 34 are grouped as one set. Furthermore, pairs of two connecting parts 34b01 and 34b02, 34b03 and 34b04, 34b05 and 34b06, 34b07 and 34b08 merge with each other by a T-shaped tube 36 respectively, and 12 heat transfer tubes 24 are connected to each flow dividing tube 23b as a group of heat transfer tubes.

[0049] Therefore, the flow dividing tubes of the upper heat exchanger part 51a have a total of eight tubes, namely four flow dividing tubes 23a1 in the upper half and four flow dividing tubes 23a2 in the lower half. Since the flow dividing tubes of the lower heat exchanger part 51b merge with each other by a T-shaped tube 36, they have four flow dividing tubes 23b, which is half the number of the flow dividing tubes of the upper heat exchanger part 51a.

[0050] In the above description, a plurality of refrigerant flow paths in the outdoor heat exchanger 5 are formed by the plurality of heat transfer tubes 24 and the plurality of flow dividing tubes 23 (23a1, 23a2, 23b) connected to these plurality of heat transfer tubes 24.

[0051] Each of the four flow dividing tubes 23a1 in the upper half of the upper heat exchanger part 51a is connected to a flow divider 30a1 for the upper half in the upper flow divider 30. Each of the four flow dividing tubes 23a2 in the lower half of the upper heat exchanger part 51a is connected to a flow divider 30a2 for the lower half in the upper flow divider 30. Each of the four flow dividing tubes 23b of the lower heat exchanger part 51b is connected to a lower flow divider 31. The upper flow divider 30 and the lower flow divider 31 correspond to a flow divider 32 that connects between each flow dividing tube 23 and the outdoor unit liquid pipe 91L (see FIG. 1).

[0052] The flow divider 32 is connected to the outdoor unit liquid pipe 91L by a branch pipe 29 having a larger diameter than the flow divider pipe 23. The branch pipe 29 has a main pipe 29 and two branch pipes 29a for the upper heat exchanger section and 29b for the lower heat exchanger section that branch off from the main pipe 29. The branch pipe 29a for the upper heat exchanger section has an upper branch pipe 29a1 connected to the upper half flow divider 30a1 and a lower branch pipe 29a2 connected to the lower half flow divider 30a2. The branch pipe 29b for the lower heat exchanger section is connected to the lower half flow divider 31. The branch pipes 29a for the upper heat exchanger section and 29b for the lower heat exchanger section are connected to the outdoor unit liquid pipe 91L via the main pipe 29.

[0053] In addition, in each heat transfer tube 24 of the outdoor heat exchanger 5, which consists of an upper heat exchanger section 51a and a lower heat exchanger section 51b, a connecting tube 37 is connected to the end opposite to the end on the side of the branch pipes 23a1, 23a2, and 23b. Each connecting tube 37 is connected to a header 25 which is connected to a four-way valve 4 (see Figure 1).

[0054] In this embodiment, as shown in Figure 4, the upper part of the air passage 20 is blocked by the rear end 14e of the electrical equipment box 14, resulting in less airflow near the top of the outdoor heat exchanger 5 than in other areas. Therefore, the refrigerant flowing through the upper passage 5p where airflow is insufficient may not condense sufficiently when the outdoor heat exchanger 5 functions as a condenser, and may not evaporate sufficiently when the outdoor heat exchanger 5 functions as an evaporator, potentially resulting in insufficient heat exchange between the refrigerant and air.

[0055] Therefore, in this embodiment, among the multiple refrigerant flow paths in the outdoor heat exchanger 5, the refrigerant flow path including the heat transfer tube group whose ventilation is obstructed by the electrical equipment box 14 is designated as the first refrigerant flow path, and the refrigerant flow paths other than the first refrigerant flow path are designated as the second refrigerant flow paths. The first and second refrigerant flow paths are formed such that the amount of refrigerant flowing per unit time (mass flow rate, hereinafter the same) in the first refrigerant flow path is less than the amount of refrigerant flowing per unit time (mass flow rate, hereinafter the same) in the second refrigerant flow path.

[0056] This allows for a reduction in the size of the outdoor unit 1 while minimizing the adverse effects on the outdoor heat exchanger 5 caused by the arrangement of the electrical equipment box 14, thereby ensuring the required amount of heat exchange between refrigerant and air in the outdoor heat exchanger 5. The lower limit of the amount of refrigerant flowing per unit time through the first refrigerant flow path is not particularly limited, as long as it is an amount that can ensure the required amount of heat exchange between refrigerant and air in the refrigerant flow path (first refrigerant flow path) including the heat transfer tube group whose ventilation is obstructed by the electrical equipment box 14.

[0057] The first refrigerant flow path is not limited to a group of heat transfer tubes 24 consisting of one group and a diversion pipe 23 connected to these heat transfer tubes 24, but may also consist of a group of heat transfer tubes 24 consisting of two or more groups and a diversion pipe 23 connected to these heat transfer tubes 24. In this embodiment, for example, the refrigerant flow path formed by a group of heat transfer tubes located in the upper half of the upper heat exchanger section 51a and a plurality of diversion pipes 23a1 connected thereto corresponds to the first refrigerant flow path. In the example in Figure 5, the diversion pipe 23a1 branching from the upper half diversion device 30a1 and the heat transfer tube 24 connected thereto correspond to the first refrigerant flow path.

[0058] The second refrigerant flow path is a refrigerant flow path other than the first refrigerant flow path. In this embodiment, the second refrigerant flow path corresponds to the refrigerant flow path formed by the heat transfer tube group located in the lower half of the upper heat exchanger section 51a and the plurality of branch pipes 23a2 connected thereto, and the refrigerant flow path formed by each heat transfer tube group in the lower heat exchanger section 51b and the plurality of branch pipes 23b connected thereto. In the example shown in Figure 5, the branch pipe 23a2 branching from the lower half branch 30a2 and the heat transfer tube 24 connected thereto correspond to the second refrigerant flow path.

[0059] When the second refrigerant flow path is formed by multiple refrigerant flow paths, the flow resistance of the refrigerant in each of the refrigerant flow paths forming the second refrigerant flow path does not need to be the same. For example, the second refrigerant flow path may include multiple refrigerant flow paths with different amounts of refrigerant flowing per unit time, corresponding to the difference in the amount of air received by the rotation of the outdoor fan 5F. The flow resistance of the refrigerant is adjusted by the length of the heat transfer tubes 24 forming the refrigerant flow path, the cross-sectional area of ​​the flow path, etc. Another way to increase the flow resistance is to provide a capillary tube in the flow path where you want to increase the flow resistance.

[0060] For example, the refrigerant flow path near the center of the outdoor heat exchanger 5 has a larger airflow than other refrigerant flow paths, resulting in a relatively larger heat exchange rate. Taking this difference in airflow into consideration, the flow resistance of the refrigerant flow path near the center may be made smaller than that of other refrigerant flow paths so that the amount of refrigerant per unit time is greater in that path than in other refrigerant flow paths. This ensures that the required amount of heat exchange in the outdoor heat exchanger 5 is secured without reducing the amount of refrigerant circulating in the refrigerant circuit 110 (refrigerant circulation rate).

[0061] The amount of refrigerant flowing per unit time through a refrigerant channel (hereinafter also referred to as the refrigerant flow rate) can be adjusted by the length and cross-sectional area (inner diameter) of the refrigerant channel. For example, by making the flow resistance of the refrigerant flowing through the first refrigerant channel greater than the flow resistance of the refrigerant flowing through the second refrigerant channel, the refrigerant flow rate in the first refrigerant channel can be made less than the refrigerant flow rate in the second refrigerant channel.

[0062] In this embodiment, the flow resistance of the refrigerant flowing through the first and second refrigerant flow paths is the flow resistance designed on the condition that the amount of refrigerant flowing through each flow path is the same. For example, if each refrigerant flow path is designed to have the same flow resistance, and the amount of refrigerant flowing through each flow path is not the same, then the flow resistance of the refrigerant flow path with a larger amount of refrigerant flowing through it will be greater than that of the other refrigerant flow paths. Therefore, the above flow resistance refers to the flow resistance determined by structural factors of the pipes, such as the length and flow path cross-sectional area of ​​the heat transfer tubes 24 and diversion tubes 23 that form the refrigerant flow path, and is not affected by the amount of refrigerant flowing into each refrigerant flow path due to the influence of gravity, etc.

[0063] As an example, Figure 6 schematically shows the degree of flow resistance in each refrigerant flow path when the refrigerant flow path of the outdoor heat exchanger 5 is divided into 10 sections vertically, in five stages. Here, a larger numerical value indicates greater flow resistance. As mentioned above, the uppermost region of the outdoor heat exchanger 5 has obstructed ventilation due to the arrangement of the electrical equipment box 14, so the refrigerant flow path belonging to this region (first refrigerant flow path) is designed to have greater refrigerant flow resistance than the other refrigerant flow paths (second refrigerant flow paths). On the other hand, in the lowermost region of the outdoor heat exchanger 5, refrigerant tends to accumulate more easily than in other regions due to the effect of gravity, especially when the amount of refrigerant circulating in the refrigerant circuit 110 is relatively large. Therefore, the flow resistance of the refrigerant flow path belonging to this lowermost region may be greater than the flow resistance of the uppermost refrigerant flow path (first refrigerant flow path).

[0064] The cross-sectional area of ​​the heat transfer tube 24 forming the first refrigerant flow path may be smaller than the cross-sectional area of ​​the heat transfer tube 24 forming the second refrigerant flow path. Alternatively, the cross-sectional area of ​​the diversion pipe 23 forming the first refrigerant flow path may be smaller than the cross-sectional area of ​​the diversion pipe 23 forming the second refrigerant flow path. These structures also make it possible to reduce the refrigerant flow rate in the first refrigerant flow path to be less than the refrigerant flow rate in the second refrigerant flow path.

[0065] Alternatively, if, among a plurality of heat transfer tube groups, a heat transfer tube group in which a plurality of heat transfer tubes forming a first refrigerant flow path are connected in series is designated as the first heat transfer tube group, and a heat transfer tube group in which a plurality of heat transfer tubes forming at least a part of the second refrigerant flow path are connected in series is designated as the second heat transfer tube group, the number of connected heat transfer tubes in the first heat transfer tube group may be greater than the number of connected heat transfer tubes in the second heat transfer tube group. With such a structure, the length of the first refrigerant flow path becomes longer than that of the second refrigerant flow path, and the flow resistance of the refrigerant flowing through the first refrigerant flow path becomes greater than the flow resistance of the refrigerant flowing through the second refrigerant flow path, so that the amount of refrigerant flowing through the first refrigerant flow path can be reduced compared to the amount of refrigerant flowing through the second refrigerant flow path.

[0066] Furthermore, with this structure, compared to the case where the flow path cross-sectional area of ​​the heat transfer tubes 24 differs between the first heat transfer tube group and the second heat transfer tube group, the size of the insertion holes for the heat transfer tubes 24 formed in the heat sink 33 can all be the same. This simplifies the design of the heat sink 33, and the insertion of the heat transfer tubes 24 into the heat sink 33 and the subsequent expansion work can be performed in the same way for all heat transfer tubes, thereby improving the ease of assembly of the outdoor heat exchanger 5.

[0067] Alternatively, if, among the multiple diversion pipes 23, one diversion pipe forming the first refrigerant flow path (for example, diversion pipe 23a1 in Figure 5) is designated as the first diversion pipe, and one diversion pipe forming the second refrigerant flow path (for example, diversion pipe 23a2 in Figure 5) is designated as the second diversion pipe, the length of the first diversion pipe may be longer than the length of the second diversion pipe. With such a structure, the flow resistance of the refrigerant flowing through the first refrigerant flow path becomes greater than the flow resistance of the refrigerant flowing through the second refrigerant flow path, so that the amount of refrigerant flowing through the first refrigerant flow path can be reduced compared to the amount of refrigerant flowing through the second refrigerant flow path.

[0068] As described above, in this embodiment, the first and second refrigerant passages of the outdoor heat exchanger 5 are formed such that the amount of refrigerant per unit time flowing through the first refrigerant passage, whose ventilation is obstructed by the electrical equipment box 14, is less than the amount of refrigerant per unit time flowing through the second refrigerant passages other than the first refrigerant passage. This reduces the adverse effects on the outdoor heat exchanger 5 caused by the arrangement of the electrical equipment box 14 and ensures the required amount of heat exchange between refrigerant and air in the outdoor heat exchanger 5.

[0069] As shown in Figure 4, the above-mentioned effects are advantageous when at least a portion of the electrical equipment box 14 is positioned on the side of the outdoor heat exchanger 5, rather than along the imaginary line V that connects the top of the outdoor heat exchanger 5 and the top of the rotation trajectory of the impeller P when the outdoor fan 5F is rotating, using the shortest distance. Therefore, since the electrical equipment box 14 can be positioned above the machine room 11 and the blower room 12, even if a refrigerant leak occurs in an air conditioning system that uses a flammable refrigerant that has a higher specific gravity than air in its gaseous state, it is possible to prevent the electrical equipment box 14 from igniting due to contact with the leaked refrigerant accumulating at the bottom of the machine room 11.

[0070] Figure 7 is a schematic diagram showing the positional relationship between the outdoor heat exchanger 5, the outdoor fan 5F, and the electrical component box 14 when viewed from above the housing 10. In the figure, A is the length of the outdoor heat exchanger 5 located on the blower room 12 side from the partition plate 13 in the left-right direction, B is the length of the outdoor heat exchanger 5 located on the blower room 12 side from the partition plate 13 in the front-rear direction, and C is the length of the electrical component box 14 located on the blower room 12 side from the partition plate 13 in the left-right direction.

[0071] In this embodiment, as shown in Figure 7, the electrical component box 14 is positioned such that the length (C) of the portion of the electrical component box 14 located on the blower room 12 side from the partition plate 13 is more than half the length (A + B) of the outdoor heat exchanger 5 located on the blower room 12 side from the partition plate 13. Generally, heat exchangers are designed assuming that the airflow will be reduced to about 50% due to the accumulation of dust and other debris. According to this embodiment, even when an electrical component box 14 is provided such that its length (C) is more than half the length (A + B) of the outdoor heat exchanger 5, it is possible to use an electrical component box 14 with a large volume while still ensuring the heat exchange amount assumed in the outdoor heat exchanger 5, thus allowing for larger board sizes for control boards and power supply boards housed inside the electrical component box 14.

[0072] 1...Outdoor unit 2...Indoor unit 3...Compressor 4...Four-way valve 5...Outdoor heat exchanger 5F...Outdoor fan (blower fan) 7...Expansion valve 8...Indoor heat exchanger 9...Refrigerant piping 10...Enclosure (outdoor unit enclosure) 11...Machine room 12...Blower room 13...Partition plate 14...Electrical component box 20...Air passage 23 (23a1, 23a2, 23b)...Diverter pipe 24...Heat transfer tube 32...Diverter 51a...Upper heat exchanger section 51b...Lower heat exchanger section 100...Air conditioning system 110...Refrigerant circuit

Claims

1. An air conditioning system comprising a refrigerant circuit having an outdoor unit, an indoor unit, and refrigerant piping connecting the outdoor unit and the indoor unit, wherein the outdoor unit comprises a compressor, an outdoor heat exchanger having a plurality of refrigerant flow paths including a plurality of heat transfer tube groups and a plurality of branch pipes connecting the plurality of heat transfer tube groups and the refrigerant piping, a blower fan, an electrical component box housing a control board for controlling the drive of the compressor and the blower fan, and an outdoor unit housing that houses the compressor, the outdoor heat exchanger, the blower fan and the electrical component box, wherein the plurality of heat transfer tube groups are formed by connecting a plurality of heat transfer tubes arranged in a vertical direction, The outdoor unit housing has a partition plate that divides it into a machine room where the compressor is located and a blower room where at least a part of the outdoor heat exchanger, the blower fan, and the electrical components box is located, an intake port for taking air from outside the outdoor unit into the blower room by the rotation of the blower fan, and an outlet port for blowing air from the blower room to outside the outdoor unit by the rotation of the blower fan, the electrical components box is located between the outdoor heat exchanger and the blower fan in an air passage formed between the intake port and the outlet port, and the first refrigerant flow path and the second refrigerant flow path are formed such that, when a refrigerant flow path including a group of heat transfer tubes whose ventilation is obstructed by the electrical components box is designated as the first refrigerant flow path and the refrigerant flow paths other than the first refrigerant flow path are designated as the second refrigerant flow path, the amount of refrigerant per unit time flowing through the first refrigerant flow path is less than the amount of refrigerant per unit time flowing through the second refrigerant flow path among the plurality of refrigerant flow paths, the first refrigerant flow path and the second refrigerant flow path are formed such that, among the plurality of refrigerant flow paths, the refrigerant flow path including a group of heat transfer tubes whose ventilation is obstructed by the electrical components box is designated as the first refrigerant flow path, and the refrigerant flow paths other than the first refrigerant flow path are designated as the second refrigerant flow path.

2. An air conditioning system according to claim 1, wherein the flow resistance of the refrigerant flowing through the first refrigerant flow path is greater than the flow resistance of the refrigerant flowing through the second refrigerant flow path.

3. An air conditioning system according to claim 2, wherein the cross-sectional area of ​​the heat transfer tubes forming the first refrigerant flow path is smaller than the cross-sectional area of ​​the heat transfer tubes forming the second refrigerant flow path.

4. An air conditioning system according to claim 2, wherein the cross-sectional area of ​​the branch pipe forming the first refrigerant flow path is smaller than the cross-sectional area of ​​the branch pipe forming the second refrigerant flow path.

5. An air conditioning system according to claim 1, wherein the plurality of heat transfer tube groups includes a first heat transfer tube group in which a plurality of heat transfer tubes forming a first refrigerant flow path are connected in series, and a second heat transfer tube group in which a plurality of heat transfer tubes forming at least a part of the second refrigerant flow path are connected in series, and the number of heat transfer tubes connected in the first heat transfer tube group is greater than the number of heat transfer tubes connected in the second heat transfer tube group.

6. An air conditioning system according to claim 1, wherein the refrigerant circuit is filled with a flammable refrigerant that has a specific gravity greater than air in a gaseous state, and the electrical equipment box is located above the blower room.

7. An air conditioning system according to claim 6, wherein the blower fan has a rotating shaft and an impeller attached to the rotating shaft, and when viewed from the left-right direction of the outdoor unit housing, a straight line is defined as the shortest distance connecting the top of the outdoor heat exchanger and the top of the rotational trajectory of the impeller when the blower fan is rotating, at least a part of the electrical equipment box is positioned on the outdoor heat exchanger side of the straight line.

8. An air conditioning system according to claim 1, wherein the outdoor unit further includes a flow divider that divides the refrigerant from the refrigerant piping into the first refrigerant flow path and the second refrigerant flow path when the outdoor heat exchanger functions as an evaporator, and the plurality of flow dividers include a first flow divider connected to the flow divider and forming the first refrigerant flow path, and a second flow divider connected to the flow divider and forming the second refrigerant flow path, wherein the length of the first flow divider is longer than the length of the second flow divider.

9. An air conditioning system according to claim 1, wherein the electrical component box is arranged such that, when viewed from above the outdoor unit housing, the length of the portion of the electrical component box located on the blower room side from the partition plate is half or more of the length of the outdoor heat exchanger located on the blower room side from the partition plate.

10. An air conditioning device according to claim 1, wherein the second refrigerant flow path includes a plurality of refrigerant flow paths, each having a different amount of refrigerant flowing per unit time, corresponding to the difference in the amount of air received by the rotation of the blower fan.

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