Air conditioner and outdoor unit thereof

Abstract

The present application relates to the technical field of air treatment, and discloses an air conditioner. The air conditioner comprises: a housing (10) provided with an air inlet (17); a fan (20) for driving air to flow; and a micro-channel heat exchanger for exchanging heat with air driven by the fan. The micro-channel heat exchanger comprises: a fin (32) provided with at least one first flat tube groove (321) and at least one second flat tube groove (322), the side of the fin (32) closer to the air inlet (17) being a windward side; and a plurality of flat tubes (31), each of which has a windward end (31b) closer to the air inlet (17) and a leeward end (31c) opposite to the windward end, the plurality of flat tubes (31) comprising at least one flat tube unit, and the flat tube unit comprising: a first flat tube (311) inserted into a first flat tube groove (321); and a second flat tube (312) inserted into a second flat tube groove (322), the second flat tube (312) being located below the first flat tube (311). In the width direction of the flat tubes, the distance from the leeward end of the first flat tube (311) to the windward side of the fin (32) is W1, and the distance from the leeward end (31c) of the second flat tube (312) to the windward side (32b) of the fin (32) is W2, wherein W2<W1. The present air conditioner can shorten drainage time on the micro-channel heat exchanger.

Description

Air conditioner and outdoor unit thereof

[0001] This application claims priority to Chinese Patent Application No. 202411376598.4, filed on September 29, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of air treatment, in particular to an air conditioner and an outdoor unit thereof. BACKGROUND

[0003] An air conditioner is a device for adjusting the temperature, humidity, air cleanliness or air flow of indoor air. The air conditioner discharges cooled air obtained by a refrigeration cycle, which is usually composed of processes of compression, condensation, expansion and evaporation of a refrigerant, to an indoor space, or discharges heated air obtained by reversing the above processes to an indoor space, thereby adjusting the indoor air. Both condensation and evaporation of the refrigeration cycle use a heat exchanger.

[0004] Generally, the heat exchanger in the air conditioner is mostly a conventional finned tube heat exchanger. Although the micro-channel heat exchanger is widely concerned due to its high efficiency and low cost, the micro-channel heat exchanger uses flat tubes, which are arranged in the horizontal direction. When operating in a low-temperature condition, the condensed water generated by the heat exchanger is prone to stay on the surface of the flat tube, which will prolong the drainage period of the micro-channel heat exchanger. The retained water quickly freezes in the next heating period, resulting in a significant performance degradation of the heat exchanger. SUMMARY

[0005] Some embodiments of the present application provide an air conditioner that can shorten the drainage time on the micro-channel heat exchanger.

[0006] In one aspect of the present application, an air conditioner is provided, comprising: a housing, which is provided with an air inlet for air to flow in; a fan, which is arranged in the housing and is used to drive air flow; and a micro-channel heat exchanger, which is used to exchange heat with the air driven by the fan; wherein the micro-channel heat exchanger comprises: a fin, which is provided with at least one first flat tube slot and at least one second flat tube slot, and one side of the fin close to the air inlet is a windward side; a plurality of flat tubes, which have a windward end close to the air inlet and a leeward end opposite to the windward end, and the plurality of flat tubes comprise at least one flat tube unit, the flat tube unit comprising: a first flat tube, which is inserted into the first flat tube slot; and a second flat tube, which is inserted into the second flat tube slot and is located below the first flat tube.

[0007] Wherein, along the width direction of the flat tube, the distance from the leeward end of the first flat tube to the windward side of the fin is W1, the distance from the leeward end of the second flat tube to the windward side of the fin is W2, and x = (W1-W2) > 0.

[0008] In another aspect of the present application, an outdoor unit of an air conditioner is provided, comprising: a housing, provided with an air inlet for air to flow in; a fan, provided in the housing, for driving air flow; and a micro-channel heat exchanger, for exchanging heat with the air driven by the fan; wherein the micro-channel heat exchanger comprises: a fin, provided with at least one first flat tube slot and at least one second flat tube slot, one side of the fin close to the air inlet being a windward side; a plurality of flat tubes, having a windward end close to the air inlet, and a leeward end opposite to the windward end, the plurality of flat tubes comprising at least one flat tube unit, the flat tube unit comprising: a first flat tube, inserted into the first flat tube slot; and a second flat tube, inserted into the second flat tube slot, the second flat tube being located below the first flat tube.

[0009] wherein along the width direction of the flat tube, the distance from the leeward end of the first flat tube to the windward side of the fin is W1, the distance from the leeward end of the second flat tube to the windward side of the fin is W2, and x = (W1-W2) > 0.

[0010] It is found through research and experiments that part P1 of the lower surface of the flat tube close to the leeward side has water retention, while part P2 of the lower surface of the flat tube close to the windward side has no water retention, and the water flowing down on P1 will continue to flow to the upper surface of the lower flat tube, causing the water retention time on the flat tube to be prolonged. In the present application, by setting the distance from the leeward end of the first flat tube to the windward side of the fin as W1, the distance from the leeward end of the second flat tube to the windward side of the fin as W2, and x = (W1-W2) > 0, the part or even the whole of the first flat tube lower surface condensation water flows downward to the x area of the leeward side of the second flat tube, and since there is no second flat tube in the x area, the flow of the condensation water can be accelerated, thereby shortening the drainage time on the heat exchanger. BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1 shows a schematic diagram of an air conditioner according to some embodiments;

[0012] FIG. 2 shows a schematic diagram of a refrigerant circuit of an air conditioner according to some embodiments;

[0013] FIGS. 3 and 4 show perspective views of an outdoor unit of an air conditioner according to some embodiments;

[0014] FIG. 5 shows a cross-sectional view of an outdoor unit of an air conditioner according to some embodiments;

[0015] FIG. 6 shows a cross-sectional view of a heat exchanger of a conventional technology;

[0016] FIG. 7 shows a side view of a fin of a heat exchanger of a conventional technology;

[0017] FIG. 8 shows a drainage path diagram on a flat tube of a heat exchanger according to some embodiments;

[0018] FIG. 9 shows a cross-sectional view of a heat exchanger, according to some embodiments;

[0019] FIG. 10 shows a side view of a fin in a heat exchanger, according to some embodiments;

[0020] FIG. 11 shows a force diagram of condensation water on a fin of a heat exchanger, according to some embodiments;

[0021] FIG. 12 and FIG. 13 show side views of a heat exchanger, according to some embodiments;

[0022] FIG. 14 shows a side view of a heat exchanger, according to some other embodiments;

[0023] FIG. 15 shows a side view of a heat exchanger, according to some embodiments;

[0024] FIG. 16 shows a side view of a heat exchanger, according to yet some other embodiments;

[0025] FIG. 17 shows a side view of a heat exchanger, according to still some other embodiments;

[0026] FIG. 18 shows a cross-sectional view of FIG. 17 along E-E;

[0027] FIG. 19 shows a line graph of the deflection angle of a water guide portion versus the amount of water stored on the water guide portion;

[0028] FIG. 20 shows a force diagram of a droplet on a flat tube, according to some embodiments;

[0029] FIG. 21 shows a cross-sectional view of a flat tube, according to some other embodiments;

[0030] FIG. 22 shows a force diagram of a droplet on a flat tube, according to some other embodiments;

[0031] FIG. 23 shows a cross-sectional view of a flat tube, according to yet some other embodiments.

[0032] Embodiments of the present application

[0033] For the purpose of clarity and a complete understanding of the present application, the present exemplary embodiments will be described with reference to the accompanying drawings, in which:

[0034] For the purpose of clarity and a complete understanding of the present application, the present exemplary embodiments will be described with reference to the accompanying drawings, in which:

[0035] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0036] The terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0037] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] <Structure of air conditioner>

[0039] Referring to FIG. 1, an air conditioner according to an embodiment of the present application includes an outdoor unit 100 located in an outdoor space to perform heat exchange between a refrigerant and outdoor air, and an indoor unit 200 located in an indoor space to perform heat exchange between a refrigerant and indoor air.

[0040] FIG. 1 is an example of a multi-split system, in which the indoor unit 200 has a plurality of indoor units 200. However, the air conditioner of the present application is also applicable to the case of one indoor unit 200.

[0041] Referring to FIG. 2, the outdoor unit 100 includes a compressor 111 to compress a refrigerant, an outdoor heat exchanger 112 to perform heat exchange between outdoor air and a refrigerant, a four-way valve 113 to selectively guide the refrigerant compressed by the compressor 111 to the outdoor heat exchanger 112 or the indoor unit 200 according to a heating mode or a cooling mode, an outdoor throttling device 114 to decompress the refrigerant guided to the outdoor heat exchanger 112 in the heating mode, and a receiver 115 to prevent the liquid refrigerant not evaporated from flowing to the compressor 111.

[0042] The compressor 111 compresses low-pressure gaseous refrigerant to high pressure using the rotational force of a compressor motor (not shown) when the compressor 111 is powered on.

[0043] The four-way valve 113 guides the refrigerant compressed in the compressor 111 to the outdoor heat exchanger 112 in the cooling mode, and guides the refrigerant compressed in the compressor 111 to the indoor unit 200 in the heating mode.

[0044] The outdoor heat exchanger 112 condenses the refrigerant compressed by the compressor 111 in the cooling mode, and evaporates the refrigerant decompressed by the indoor unit 200 in the heating mode.

[0045] The outdoor fan 116 blows outdoor air to the outdoor heat exchanger 112.

[0046] The outdoor throttling device 114 decompresses the refrigerant by using a throttling action on the refrigerant. When the refrigerant passes through a narrow passage, the pressure of the refrigerant decreases without heat exchange with the outside. The outdoor throttling device 114 can be an expansion valve or a capillary tube, etc.

[0047] The indoor unit 200 includes an indoor heat exchanger 211 that performs heat exchange between the refrigerant and indoor air, and an indoor throttling device 212 that decompresses the refrigerant supplied to the indoor heat exchanger 211 in the cooling mode.

[0048] The indoor heat exchanger 211 evaporates the refrigerant in the cooling mode, and condenses high-pressure gaseous refrigerant in the heating mode.

[0049] Hereinafter, the flow of the refrigerant in the cooling mode or the heating mode of the air conditioner will be described.

[0050] When the air conditioner operates in the cooling mode, the refrigerant is compressed to high pressure by the compressor 111 of the outdoor unit 100. As the refrigerant is compressed, the pressure and temperature of the refrigerant increase.

[0051] The compressed refrigerant is guided to the outdoor heat exchanger 112 through the four-way valve 113. The refrigerant is condensed in the outdoor heat exchanger 112, and heat exchange between the refrigerant and outdoor air is performed while the refrigerant is condensed. Specifically, the state of the refrigerant changes from gaseous to liquid.

[0052] After passing through the outdoor throttling device 114, the condensed refrigerant is supplied to the indoor unit 200.

[0053] The refrigerant provided to the indoor unit 200 is decompressed by the indoor throttling device 212 while the refrigerant becomes low-temperature low-pressure, two-phase state refrigerant.

[0054] The reduced-pressure refrigerant is evaporated by the indoor heat exchanger 211, and heat exchange between the refrigerant and the indoor air is performed while the refrigerant is evaporated. Specifically, the state of the refrigerant changes to a gaseous state.

[0055] The evaporated gaseous refrigerant is supplied to the outdoor unit 100 after passing through the indoor heat exchanger 211, and is supplied to the accumulator 115 via the four-way valve 113. In the accumulator 115, the refrigerant is separated into liquid refrigerant that is not evaporated and gaseous refrigerant that is evaporated, and the gaseous refrigerant is again supplied to the compressor 111, completing one cycle of the refrigerant.

[0056] As described above, in the cooling mode, the air conditioner can cool the indoor air using heat exchange between the refrigerant and the indoor air generated in the indoor heat exchanger 211.

[0057] When the air conditioner operates in the heating mode, the refrigerant is compressed to a high pressure by the compressor 111 of the outdoor unit 100, and the temperature of the refrigerant increases as the pressure of the refrigerant increases.

[0058] The compressed refrigerant is guided to the indoor unit 200 after passing through the four-way valve 113.

[0059] The refrigerant is condensed by the indoor heat exchanger 211, and heat exchange between the refrigerant and the indoor air is performed while the refrigerant is condensed. Specifically, the state of the refrigerant changes from a gaseous state to a liquid state.

[0060] The condensed refrigerant is again supplied to the outdoor unit 100 after passing through the indoor heat exchanger 211.

[0061] The refrigerant supplied to the outdoor unit 100 is reduced in pressure by the outdoor throttling device 114 while the refrigerant becomes a low-temperature, low-pressure, two-phase state.

[0062] The reduced-pressure refrigerant is evaporated by the outdoor heat exchanger 112, and heat exchange between the refrigerant and the outdoor air is performed while the refrigerant is evaporated. Specifically, the state of the refrigerant changes to a gaseous state.

[0063] The gaseous refrigerant evaporated by the outdoor heat exchanger 112 is supplied to the accumulator 115 via the four-way valve 113. In the accumulator 115, the refrigerant is separated into liquid refrigerant that is not evaporated and gaseous refrigerant that is evaporated, and the gaseous refrigerant is again supplied to the compressor 111, completing one cycle of the refrigerant.

[0064] As described above, in the heating mode, the air conditioner can heat the indoor air using heat exchange between the refrigerant and the indoor air generated in the indoor heat exchanger 211.

[0065] In this application, the outdoor heat exchanger 112 and the indoor heat exchanger 211 are also referred to as heat exchangers. The outdoor fan 116 and the indoor fan 213 are also referred to as fans.

[0066] The following will be described by taking the outdoor unit of an air conditioner as an example:

[0067] Referring to FIGS. 3 to 5, the air conditioner, for example, the outdoor unit, comprises a housing 10 in the shape of a cuboid box.

[0068] The housing 10 is provided with an air inlet 17 for air to flow into the housing 10. The housing 10 is provided with an air outlet 18 for air in the housing 10 to be discharged.

[0069] The housing 10 comprises a support bottom plate 11 and frame columns 12 connected at four corners of the support bottom plate 11. The frame columns 12 serve to support the entire machine.

[0070] The side of the housing 10 is provided with a grating plate 13 connected with the frame columns 12. The grating holes on the grating plate 13 form the air inlet 17.

[0071] In some variable embodiments, no plate can be arranged between the frame columns 12, so that the space between the frame columns 12 forms the air inlet 17.

[0072] In some embodiments, the side of the housing 10 is provided with a cover plate 14 connected with the frame columns 12, which has the function of covering the internal components of the housing 10.

[0073] In some embodiments, the rear side of the housing 10 is not provided with the cover plate 14 and the grating plate 13; the left side and the left part of the front side of the housing 10 are provided with the grating plate 13; the rear part of the right side of the housing 10 is provided with the grating plate 13. Therefore, the rear side, the left side, the left part of the front side, and the rear part of the right side of the housing 10 form the air inlet 17 for air to enter the housing 10.

[0074] For example, the right part of the front side of the housing 10 is provided with the cover plate 14. The front part of the right side of the housing 10 is provided with the cover plate 14, which can be integrally formed with the grating plate 13 of the rear part thereof.

[0075] The components related to the refrigerant, such as the compressor 111, can be connected to the support bottom plate 11. The cover plate 14 can cover the compressor 30 and the like to serve as a protective function.

[0076] The top end of the housing 10 is open to form the air outlet 18.

[0077] The air conditioner comprises a heat exchanger 30 arranged in the interior of the housing 10 corresponding to the air inlet 17. The heat exchanger 30 is used for heat exchange from the air introduced into the air inlet 17, and sends the airflow after heat exchange.

[0078] The air conditioner includes a fan 20. The fan 20 is disposed in the housing 10 corresponding to the air outlet 18, and is used to drive air flow. The fan 20 can be located between the heat exchanger 30 and the air outlet 18. The fan 20 can be an axial fan.

[0079] With reference to Fig. 5, arrows schematically show the direction of air flow when the fan 20 is in operation. Air can flow from the air inlet 17, through the heat exchanger 30, and to the air outlet 18.

[0080] <Structure of the heat exchanger>

[0081] With reference to Figs. 6 and 7, the heat exchanger 30 can be a micro-channel heat exchanger. The micro-channel heat exchanger has a plurality of flat tubes 31 and fins 32.

[0082] The flat tubes 31 are used for flowing refrigerant therethrough, and the fins 32 are connected to the flat tubes 31 to increase the surface area of the flat tubes 31 and improve the heat exchange efficiency between the refrigerant and air.

[0083] The flat tube 31 is a porous tube having a plurality of flow-through holes 31a that form refrigerant flow paths. The refrigerant exchanges heat with air when flowing through each flow-through hole 31a of the flat tube 31. The plurality of flow-through holes 31a are arranged in the flat tube 31 along the direction of air flow relative to the heat exchanger 30.

[0084] The fin 32 can have a tab structure. The fin 32 is provided with a flat tube slot 32a that is adapted to the flat tube 31 and used to mount the flat tube 31.

[0085] The flat tube slot 32a is open at one end in the transverse direction, so that the flat tube 31 is inserted into the flat tube slot 32a from the open end.

[0086] The side of the fin 32 close to the air inlet 17 is the windward side 32b of the fin 32, and the side of the fin 32 opposite to the windward side is the leeward side of the fin 32. The open end of the flat tube slot 32a is located at the windward side of the fin 32.

[0087] The fin 32 is provided with a plurality of flat tube slots 32a arranged in the height direction, and each flat tube slot 32a is inserted with the flat tube 31.

[0088] Referring to Fig. 8, the black area represents the condensed water, and the hollow large arrow represents the air flow direction. The condensed water generated in the working process of the heat exchanger 30 will be drained downward under the action of gravity. However, due to the transverse direction of the width of the flat tube 31, part of the condensed water will be retained on the surface of the flat tube 31. The drainage path of the flat tube 31 is: ① the condensed water gathers on the upper surface of the flat tube 31 → ② the condensed water flows circumferentially along the wall of the flat tube 31 under the action of surface tension → ③ the condensed water flows downward under the action of gravity. Path ② causes the condensed water to accumulate on the lower surface of the flat tube 31, which will prolong the drainage time. Path ③ the condensed water 40 continues to flow to the upper surface of the lower flat tube 31, which continues to prolong the drainage time. In this application, the condensed water on the lower surface of the flat tube 31 is marked as condensed water 40.

[0089] In addition, during the drainage process, the condensed water continuously collects on the lower surface of the flat tube 31, and under the action of the air entrainment force, the condensed water 40 collected on the lower surface of the flat tube 31 tends to move to the leeward side of the flat tube 31.

[0090] In order to reduce the retention time of the condensed water on the flat tube 31 and shorten the drainage period on the heat exchanger 30, the following improvements are made in this application:

[0091] Referring to Fig. 9, the hollow large arrow represents the air flow direction. Two adjacent flat tubes 31 are taken as a flat tube unit, and the two flat tubes 31 are respectively a first flat tube 311 and a second flat tube 312, wherein the second flat tube 312 is located below the first flat tube 311.

[0092] The two ends of the flat tube 31 in the width direction are respectively the windward end 31b of the flat tube 31 and the leeward end 31c of the flat tube 31. The windward end 31b of the flat tube 31 is close to the air inlet 17, and the leeward end 31c of the flat tube 31 is away from the air inlet 17.

[0093] In the width direction of the flat tube 31, the distance from the leeward end 31c of the first flat tube 311 to the windward side 32b of the fin 32 is W1, and the distance from the leeward end 31c of the second flat tube 312 to the windward side 32b of the fin 32 is W2, W2 < W1. The width of the first flat tube 312 is smaller than the width of the first flat tube 311.

[0094] For convenience of description, the first flat tube 311 is divided into two parts in the width direction, the part close to the windward side of the first flat tube 311 is the windward part P2 of the first flat tube 311, and the part close to the leeward side of the first flat tube 311 is the leeward part P1 of the first flat tube 311.

[0095] In the same flat tube unit, the second flat tube 312 is located below the windward part P2 of the first flat tube 311, or the whole second flat tube 312 is located below the windward part P2 of the first flat tube 311. There is no second flat tube 312 or only a small part of the second flat tube 312 below the leeward part P1 of the first flat tube 311.

[0096] The condensed water mainly gathers on the lower surface of the leeward part P1 of the first flat tube 311 during the drainage process. When the condensed water flows downward under the action of gravity, the condensed water is not blocked by the second flat tube 312 or is blocked by a small part of the second flat tube 312 on the drainage path below, thereby shortening the drainage time of the condensed water.

[0097] According to the embodiment of the present application, referring to FIG. 10, two flat tube grooves 32a on the fin 32 corresponding to a group of flat tube units are a group of tube groove units. The two flat tube grooves 32a in the tube groove unit are a first flat tube groove 321 and a second flat tube groove 322, respectively. The second flat tube groove 322 is located below the first flat tube groove 321.

[0098] The first flat tube 311 is inserted into the first flat tube groove 321, and the second flat tube 312 is inserted into the second flat tube groove 322.

[0099] In the width direction of the flat tube 31, the distance from one end of the first flat tube groove 321 away from the windward side 32b of the fin 32 to the windward side 32b of the fin 32 is W1, and the distance from one end of the second flat tube groove 322 away from the windward side of the fin 32 to the windward side of the fin 32 is W2, W2

[0100] The present application shortens the width of the second flat tube 312, which can prevent the water flow on the first flat tube 312 from flowing onto the second flat tube 312. However, if the second flat tube 312 is too short, it will also excessively affect the heat exchange efficiency of the heat exchanger 30. Therefore, the length of the second flat tube 312 is also designed in the present application.

[0101] Referring to FIG. 11, the black area in the figure represents condensed water 40, which is affected by gravity and the wind force of air flow during the downward flow process.

[0102] Under the action of gravity and wind force, the condensed water 40 of the leeward part P1 of the first flat tube 311 moves to the lower left along the inclination angle a.

[0103] The gravity of water Fg: Fg= p w ·g·V w (2)

[0104] The water is affected by the air drag Fa:

[0105] The drag coefficient of the wind:

[0106] The Reynolds number: Re D = p a ·u a ·Fp / μ(5)

[0107] In formula (2), pw is the water density, g is the gravitational acceleration, V w is the water droplet volume.

[0108] In formula (3), p a is the air density, u a is the wind speed, A proj is the water droplet windward area.

[0109] In formula (5), Fp is the characteristic length, and μ is the viscosity.

[0110] Exemplarily, V w = 4.6*10 -9 m 3 , A proj = 1.9*10 -6 m 2 , Fp = 1.6 mm (fin pitch), and μ = 17.9*10 -6 Pa.s.

[0111] α is the inclination angle of the moving direction of the water droplet relative to the height direction of the fin, that is, the inclination angle relative to the connecting line of the first flat tube and the second flat tube in the height direction.

[0112] Under the condition that the wind speed u a = 1.0-3.0 m / s on the windward surface of the heat exchanger 30 is calculated, the range of the inclination angle α is obtained: 1.5°≤α≤9°.

[0113] Referring to FIG. 12, in the same group of flat tube units, the width of the first flat tube 311 is d1, the vertical spacing distance between the first flat tube 311 and the second flat tube 312 is z, the lateral distance x=W1-W2 between the leeward end of the first flat tube 311 and the leeward end of the second flat tube 312,

[0114] When can ensure that the condensate water 40 on the lower surface of the first flat tube 311 almost does not flow to the second flat tube 312.

[0115] Through the force analysis of the condensate water on the lower surface of the first flat tube 311, the distribution area of the part of the condensate water flowing to the height of the second flat tube 312 can be obtained: Then the second flat tube 312 originally located in the distribution area is removed, so that the condensate water 40 on the lower surface of the first flat tube 311 almost does not flow to the second flat tube 312, thereby reducing the residence time of water on the second flat tube 312, and further shortening the drainage time on the heat exchanger.

[0116] Since the condensed water on the lower surface of the first flat tube 311 flows to the left side of the second flat tube 312 along the inclination angle a in the same group of flat tube units, the present application can ensure that the condensed water on the lower surface of the first flat tube 311 almost does not flow to the second flat tube 312, thereby greatly shortening the drainage time of the condensed water on the heat exchanger 30.

[0117] In some embodiments, with the vertical line S passing through the midpoint of the width direction of the first flat tube 311 as the reference, the distance t from the leeward end 31c of the second flat tube 312 to the line S satisfies: t≤z·tan a.

[0118] When t≤0.16z, it can be ensured that the condensed water 40 on the lower surface of the first flat tube 311 almost does not flow to the second flat tube 312.

[0119] In some embodiments, if the distance from the windward end 31b of the first flat tube 311 to the windward side of the fin 32 is equal to the distance from the windward end 31b of the second flat tube 312 to the windward side of the fin 32, then the width d2 of the second flat tube 312 satisfies:

[0120] In some embodiments, on the cross section of the heat exchanger 30 orthogonal to the flow direction of the refrigerant, the sum of the areas of the flow-through holes 31a on the first flat tube 311 is equal to the sum of the areas of the flow-through holes 31a on the second flat tube 312. In this way, it can be ensured that the refrigerant flow rates in the first flat tube 311 and the second flat tube 312 are equal.

[0121] In order to achieve the equal sum of the areas of the flow-through holes 31a on the first flat tube 311 and the second flat tube 312, the thickness of the second flat tube 312 in the height direction can be made greater than the thickness of the first flat tube 311.

[0122] In some embodiments, referring to FIG. 13, the distance from the windward end 31b of the first flat tube 311 to the windward side 32b of the fin 32 is y1, and the distance from the windward end 31b of the second flat tube 312 to the windward side 32b of the fin 32 is y2, then y1 and y2 satisfy: 0≤y1≤y2.

[0123] If y1 is less than 0, it means that the windward end 31b of the first flat tube 311 protrudes outside the windward side 32b of the fin 32, so that the first flat tube 311 will block the drainage path on the windward side of the fin 32.

[0124] If y2 is less than 0, it means that the windward end 31b of the second flat tube 312 protrudes outside the windward side 32b of the fin 32, so that the second flat tube 312 will also block the drainage path on the windward side of the fin 32.

[0125] y2>y1, which means that the distance from the windward end 31b of the second flat tube 312 to the windward side 32b of the fin 32 is relatively large, which is conducive to the condensate water on the upper side of the fin 32 of the second flat tube 312 being discharged downward along the fin 32 of the windward side of the second flat tube 312.

[0126] In some embodiments, |y1-y2|≤5mm. The size of the transversely staggered windward ends 31b of the first flat tube 311 and the second flat tube 312 is relatively small, which is conducive to bending the heat exchanger 30 with the windward end of the flat tube 31 as the positioning reference.

[0127] In some embodiments, referring to FIG. 14, the fin 32 is provided with a water guide portion 323.

[0128] The lower side of the second flat tube 312 has a third flat tube 315. The third flat tube 315 has the same structure as the first flat tube 311, and the third flat tube 315 can also be the first flat tube 311 in another group of flat tube units.

[0129] The water guide portion 323 is located below the leeward end 31c of the second flat tube 312 and is used to block the spread of condensate water 40 to the lower side of the second flat tube 312.

[0130] If the condensate water flows to the lower side of the second flat tube 312, the water will continue to accumulate on the third flat tube 315 below the second flat tube 312, thereby prolonging the drainage time.

[0131] The water guide portion 323 extends vertically downward or obliquely downward on the fin 32, and the oblique direction is close to the leeward side.

[0132] The area between the second flat tube 312 and the third flat tube 315 on the fin 32 is a drainage area, and the water guide portion 323 divides the drainage area into left and right parts. Exemplarily, the area below the second flat tube 312 is the right part 3241 of the water guide portion 323.

[0133] The right part 3241 corresponds to the drainage of the fin 32 itself and the flat tube 31 above it, and the left part 3242 corresponds to the drainage of other parts of the fin 32. The water guide portion 323 can reduce the spread of water from the left part 3242 to the right part 3241.

[0134] Since the condensate water flow of the left part 3242 is greater than that of the right part 3241, the condensate water of the left part 3242 can produce siphonage to the condensate water of the right part 3241, thereby accelerating the flow speed of the water on the third flat tube 315 below the water guide portion 323.

[0135] In some embodiments, referring to FIG. 15, on a cross section of the heat exchanger 30 orthogonal to the flow direction of the refrigerant, the point on the leeward end 31c of the second flat tube 312 closest to the leeward side of the fin 32 is point Al, and the vertical line passing through the point Al is line Ql. The intersection of the line Ql and the top end profile line of the second flat tube 312 is point Jl.

[0136] On the third flat tube 315 below the second flat tube 312, the point on the leeward end 31c of the third flat tube 315 closest to the leeward side of the fin 32 is point A2, and the vertical line passing through the point A2 is line Q2, and the intersection of the line Q2 and the top end profile line of the third flat tube 315 is point J2.

[0137] The line connecting the point Jl and the point J2 is line Q3. The line Ql, the line Q3, and the top end profile line of the third flat tube 315 enclose an area, which is a water guide area 325. When all or most of the water guide portion 323 is located within the water guide area 325, the water guide portion 323 has a better effect of blocking the water above from flowing to the right side portion 3241, and the length of the water guide portion 323 is not too long.

[0138] If the top end of the water guide portion 323 exceeds the water guide area 325, for example, the top end of the water guide portion 323 is located to the right of the water guide area 325, the portion of the water guide portion 323 extending to the right of the water guide area 325 does not have the effect of blocking water, which causes waste of materials.

[0139] If the top end of the water guide portion 323 is located to the left of the water guide area 325, then part of the water above the water guide portion 323 will still flow from the top end of the water guide portion 323 to the right side of the water guide portion 323.

[0140] If the bottom end of the water guide portion 323 exceeds the water guide area 325, for example, the bottom end of the water guide portion 323 is located to the left of the water guide area 325, then the relative inclination angle of the water guide portion 323 to the vertical direction will be larger, which prolongs the flow time of the water flow on the water guide portion 323, and the water guide performance of the water guide portion 323 is weakened.

[0141] In some embodiments, the top end of the water guide portion 323 is close to the second flat tube 312, and the water guide portion 323 intersects the line Ql. Since the range of the water flowing downward on the first flat tube 311 above the second flat tube 312 is approximately located to the left of the second flat tube 312, the top end of the water guide portion 323 intersects the line Ql, and the top end of the water guide portion 323 can block the condensation water 40 flowing down on the first flat tube 311 to the maximum extent.

[0142] In some embodiments, the bottom end of the water guide portion 323 is close to the third flat tube 315, and the bottom end of the water guide portion 323 intersects the line Q3, or the bottom end of the water guide portion 323 is located to the right of the line Q3.

[0143] The bottom end of the water guide portion 323 can block water flow to the third flat tube 315 to the greatest extent.

[0144] If the bottom end of the water guide portion 323 exceeds the leeward side of the line Q3, the inclination angle of the water guide portion 323 relative to the vertical direction is relatively large, and the flow time of water in the water guide portion 323 is prolonged, and the water guide performance of the water guide portion 323 is weakened.

[0145] According to an embodiment of the present application, referring to FIG. 16, the top end of the water guide portion 323 has a spacing L1 to the lower surface of the second flat tube 312, and the bottom end of the water guide portion 323 has a spacing L2 to the lower surface of the third flat tube 315, L1≤2mm, and L2≤2mm. The spacing gap is relatively small, and the effect of blocking water flow to the rear side of the water guide portion 323 can be ensured.

[0146] In some embodiments, the inclination angle β of the water guide portion 323 relative to the height direction satisfies: β≤arctan(x / z).

[0147] If β is relatively large, the water guide portion 323 is relatively close to the horizontal direction, and the flow time of water in the water guide portion 323 is relatively long. If β≤arctan(x / z), the inclination of the water guide portion 323 in the height direction is relatively small, and the water guide portion 323 is close to the vertical direction, and the flow speed of water in the water guide portion 323 can be increased.

[0148] In an embodiment, β=arctan(x / z). At this angle, the bottom end of the water guide portion 323 is relatively close to the leeward end 31c of the third flat tube 315, and water can be better blocked to the left side of the third flat tube 315. If β<arctan(x / z), the bottom end of the water guide portion 323 is still away from the leeward end 31c of the third flat tube 315 by a distance C, and part of the water will flow to the left end of the third flat tube 315, which will prolong the discharge time of the water.

[0149] In some embodiments, the water guide portion 323 can be a protrusion provided on the fin 32. The water guide portion 323 is formed by stamping a protrusion at the position where the water guide portion 323 is provided on the fin 32. The water guide portion 323 is integrally formed with the fin 32, and the structure is relatively simple.

[0150] The water guide portion 323 can be a crack provided on the fin 32, and the crack is used to block water from flowing to the right side 3241.

[0151] The water guide portion 323 can also be a plate connected to the fin 32, for example, the plate is welded to the fin 32 to form the water guide portion 323.

[0152] In some embodiments, referring to FIG. 17 and FIG. 18, the water guide 323 can be a window provided on the fin 32. The water guide 323 has one end connected to a side wall of the opening 326 on the leeward side of the fin 32, and the other end is raised relative to the surface of the fin 32. In the projection of the surface of the fin 32, the water guide 323 is located within the opening 326.

[0153] In some embodiments, the black area in FIG. 18 represents condensed water. Since the water guide 323 is easily connected to the corner of the surface of the fin 32, it is easy to affect the drainage effect of the heat exchanger 30.

[0154] The raised angle of the water guide 323 relative to the surface of the fin 32 is γ, and γ < 30°.

[0155] Referring to FIG. 19, experimental studies have found that the water guide 323 has a good drainage effect when γ < 30°. Compared with γ = 30°, the water storage amount on the surface of the heat exchanger is reduced by about 27% when γ = 20°, and the water storage amount on the surface of the heat exchanger is increased by nearly 50% when γ = 40°, and the water storage amount on the surface of the heat exchanger is increased by about 125% when γ = 50°.

[0156] Therefore, the raised angle γ of the water guide 323 relative to the surface of the fin 32 is < 30°, which can reduce the water storage amount on the surface of the heat exchanger.

[0157] FIG. 20 is a schematic diagram of the force on the droplet / condensed water of the leeward end 31c of the flat tube 31, and the black area in the figure represents the droplet. The two end faces of the flat tube 31 in the width direction are circular arc faces.

[0158] Where G is the gravity, Fσ1 and Fσ2 are the tangential surface tension of the wall surface. Under the action of gravity and surface tension, the condensed water has a resultant force downward, that is, the droplet has a tendency to diffuse to the lower surface of the flat tube 31.

[0159] In some embodiments, referring to FIG. 21 and FIG. 22, the end face of the flat tube 31 at the leeward end 31c includes an arc segment 313, and the top end of the arc segment 313 is connected to the top face of the flat tube 31.

[0160] The end face of the flat tube 31 at the leeward end 31c includes a vertical straight line segment 314, and the top end of the straight line segment 314 is connected to the bottom end of the arc segment 313, and the bottom end of the straight line segment 314 is connected to the bottom face of the flat tube 31.

[0161] In some embodiments, the arc segment 313 is an arc face, which is used to guide the stagnant water on the upper surface of the flat tube 31 downward.

[0162] A straight line segment 314 is arranged on the end face of the flat tube 31. Since the straight line segment 314 has a specific angle with the lower surface of the flat tube 31, the surface tension of the liquid droplet at the straight line segment 314 is vertical, and there is no horizontal component force. Thus, the condensate water can be greatly reduced from being adsorbed to the lower surface of the flat tube 31 by the surface tension, thereby further accelerating the drainage speed of the heat exchanger 30.

[0163] In some embodiments, referring to FIG. 23, the end face of the flat tube 31 at the leeward end 31c includes a vertical straight line segment 314. The upper and lower ends of the straight line segment 314 are connected to the arc line segment 313, respectively.

[0164] As described above, since the surface tension of the liquid droplet at the straight line segment 314 is vertical, the condensate water can be reduced from being adsorbed to the lower surface of the flat tube 31 by the surface tension.

[0165] In some embodiments, the length of the straight line segment 314 is greater than 1 / 3 of the thickness of the flat tube 31. Thus, the straight line segment 314 has a greater length to guide the liquid droplet to drip downward.

[0166] In some embodiments, the length of the straight line segment 314 is greater than the radius of the arc line segment 313 below the straight line segment 314. Thus, the straight line segment 314 has a greater length to guide the liquid droplet to drip downward, and the arc line segment 313 is shorter, which is not conducive to the flow of the liquid droplet along the arc line segment 313.

[0167] In some embodiments, the windward end 31b of the flat tube 31 is an entire circular arc surface. The circular arc surface can promote the water on the upper surface of the flat tube 31 to flow to the lower surface on the windward side of the heat exchanger 30, and then be discharged through the fin 32.

[0168] It should be noted that the structure of the micro-channel heat exchanger of the present application is also applicable to the indoor unit of the air conditioner.

[0169] As described above, in the embodiments of the present application, the distance from the leeward end 31c of the first flat tube 311 to the windward side 32b of the fin 32 is W1 along the width direction of the flat tube 31, and the distance from the leeward end 31c of the second flat tube 312 to the windward side 32b of the fin 32 is W2, W2 < W1. Thus, in the same group of flat tube units, the second flat tube 312 is located below the windward portion P2 of the first flat tube 311, and there is no second flat tube 312 or only a small part of the second flat tube 312 below the leeward portion P1 of the first flat tube 311. Since the condensate water mainly gathers on the lower surface of the leeward portion P1 of the first flat tube 311 during the drainage process, the condensate water flows downward under the action of gravity. Since there is no second flat tube 312 or only a small part of the second flat tube 312 on the drainage path below, the drainage time of the condensate water is shortened.

[0170] In addition, the width of the first flat tube 311 is d1, the vertical spacing distance between the first flat tube 311 and the second flat tube 312 is z, and the transverse distance x between the leeward end of the first flat tube 311 and the leeward end of the second flat tube 312 satisfies x≤0.16z, so that the condensed water 40 on the lower surface of the first flat tube 311 can hardly flow to the second flat tube 312. The condensed water 40 on the lower surface of the first flat tube 311 can hardly flow to the second flat tube 312.

[0171] In addition, the vertical line S passing through the midpoint of the width direction of the first flat tube 311 is taken as a reference, and the distance t from the leeward end 31c of the second flat tube 312 to the line S satisfies t≤0.16z, so that the condensed water 40 on the lower surface of the first flat tube 311 can hardly flow to the second flat tube 312.

[0172] In addition, the sum of the areas of the flow-through holes 31a on the first flat tube 311 is equal to the sum of the areas of the flow-through holes 31a on the second flat tube 312, so that the refrigerant flow rates in the first flat tube 311 and the second flat tube 312 can be equal.

[0173] In addition, the water guide part 323 is located below the leeward end 31c of the second flat tube 312, which can block the spread of the condensed water to the windward side of the water guide part 323, so that the condensed water cannot spread below the second flat tube 312, further reducing the accumulation of water on the flat tube, improving the drainage efficiency of the heat exchanger 30, and shortening the drainage time.

[0174] In addition, the angle of the water guide part 323 relative to the surface of the fin 32 is γ, and γ<30°, which can maximize the reduction of water accumulation at the connection angle between the water guide part 323 and the surface of the fin 32.

[0175] In addition, the end surface of the flat tube 31 at the leeward end 31c includes a vertical straight line segment 314, and since the surface tension of the liquid droplets at the straight line segment 314 is vertical, the condensed water can be reduced to be adsorbed to the lower surface of the flat tube 31 by surface tension, thereby improving the drainage efficiency of the heat exchanger 30 and shortening the drainage time.

[0176] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0177] For the sake of explanation, the foregoing descriptions have been presented in terms of specific embodiments. However, it is to be appreciated that specific embodiments described herein are not intended to limit the scope of the present application, which is defined with reference to the following claims. Various modifications and changes can be made thereto by those skilled in the art which fall within the scope of the present application as defined by the following claims. The embodiments were chosen and described in order to explain the principles of the application and the practical application and to enable others skilled in the art to understand for implementing various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. An air conditioner comprising: a housing having an air inlet for air to flow into; a fan arranged in the housing for driving air flow; and a micro-channel heat exchanger for exchanging heat with the air driven by the fan; wherein the micro-channel heat exchanger comprises: a fin having at least one first flat tube slot and at least one second flat tube slot, the fin having a windward side near the air inlet; a plurality of flat tubes for flowing refrigerant, the flat tubes having a windward end near the air inlet and a leeward end opposite to the windward end, the plurality of flat tubes comprising at least one flat tube unit, the flat tube unit comprising: a first flat tube inserted into the first flat tube slot; a second flat tube inserted into the second flat tube slot, the second flat tube being below the first flat tube; wherein along a width direction of the flat tube, a distance from the leeward end of the first flat tube to the windward side of the fin is W1, a distance from the leeward end of the second flat tube to the windward side of the fin is W2, and x = (W1-W2) > 0. In the same flat tube unit, a vertical spacing distance between the first flat tube and the second flat tube is z, and a line S passing through a midpoint of the width direction of the first flat tube and parallel to a height direction is taken as a reference, the line S intersecting the second flat tube; 2. The air conditioner of claim 1, wherein, In the same group of flat tube units, the width of the first flat tube is d1, the vertical spacing distance between the first flat tube and the second flat tube is z, 3. The air conditioner according to claim 1 or 2, wherein a distance t from the leeward end of the second flat tube to the line S satisfies: t ≤ 0.16z. The flat tube comprises a third flat tube below the second flat tube, the third flat tube having the same structure as the first flat tube; 4. The air conditioner according to any one of claims 1 to 3, wherein In the same group of flat tube units, the width of the first flat tube is d1, the vertical spacing distance between the first flat tube and the second flat tube is z, Fg = p w g V w p w is the water density, g is the gravitational acceleration, V w is the water droplet volume; p a is the air density, u a is the wind speed, A proj is the water droplet wind-facing area, Re D is the Reynolds number, a is the inclination angle of the water droplet's moving direction relative to the height direction of the fin, Fg is the gravity of the water droplet, Fa is the air drag force received by the water droplet, C D is the drag coefficient of the wind.

5. The air conditioner according to any one of claims 1 to 4, wherein the fin is provided with: a water guide portion protruding from a surface of the fin or being in a groove shape, the water guide portion extending downward from a position near the leeward end of the second flat tube, or the water guide portion extending obliquely from the position near the leeward end of the second flat tube to the leeward end of the third flat tube. In a cross section of the heat exchanger orthogonal to a refrigerant flow direction, a point farthest from the windward side of the fin is point A1, a line passing through point A1 and parallel to a height direction of the heat exchanger is line Q1, and an intersection point of line Q1 and a top end contour line of the second flat tube is point J1; 6. The air conditioner of claim 5, wherein, a point farthest from the windward side of the fin is point A2, a line passing through point A2 and parallel to the height direction of the heat exchanger is line Q2, and an intersection point of line Q2 and a top end contour line of the third flat tube is point J2, and a line connecting point J1 and point J2 is line Q3; the water guide portion intersects line Q1, and a bottom end of the water guide portion intersects line Q3 or is located on a windward side of line Q3. A vertical spacing distance between the second flat tube and the third flat tube is z, and an inclination angle β of the water guide portion relative to the height direction satisfies: β ≤ arctan(x / z).

7. The air conditioner according to claim 5 or 6, wherein The water guide portion is connected to the fin at an angle γ, and γ < 30°.

8. The air conditioner according to any one of claims 5 to 7, wherein A top end of the water guide portion has a spacing L1 from a lower surface of the second flat tube, and a bottom end of the water guide portion has a spacing L2 from a lower surface of the third flat tube, L1 ≤ 2 mm, and L2 ≤ 2 mm.

9. The air conditioner according to any one of claims 5 to 8, wherein an end surface of the leeward end of the flat tube comprises:

10. The air conditioner according to any one of claims 1 to 9, wherein ​ an arc segment, which is an arc surface, connected to the top surface of the flat tube; a straight line segment, which is parallel to the height direction, connected to the lower end of the arc segment.

11. The air conditioner according to any one of claims 1 to 10, wherein The distance from the windward end of the first flat tube to the windward side of the fin is y1, and the distance from the windward end of the second flat tube to the windward side of the fin is y2, wherein y1 and y2 satisfy: 0≤y1≤y2.

12. The air conditioner according to any one of claims 1 to 11, wherein A plurality of flow-through holes are arranged in the flat tube; in a cross section of the heat exchanger that is orthogonal to the flow direction of the refrigerant, the sum of the areas of the flow-through holes in the first flat tube is equal to the sum of the areas of the flow-through holes in the second flat tube.

13. The air conditioner according to any one of claims 1 to 12, wherein The distance from the windward end of the first flat tube and the windward end of the second flat tube to the windward side of the fin is equal, and the width d2 of the second flat tube satisfies: where d1 is the width of the first flat tube, z is the vertical spacing distance between the first flat tube and the second flat tube, and a is the inclination angle of the moving direction of the water droplets relative to the height direction of the fin.

14. An outdoor unit of an air conditioner, comprising: a housing, which is provided with an air inlet for air inflow; a fan arranged in the housing for driving air flow; and a micro-channel heat exchanger for exchanging heat with the air driven by the fan; wherein the micro-channel heat exchanger comprises: a fin, which is provided with at least one first flat tube slot and at least one second flat tube slot, and one side of the fin close to the air inlet is a windward side; a plurality of flat tubes for flowing refrigerant, the flat tubes having a windward end close to the air inlet and a leeward end opposite to the windward end, and the plurality of flat tubes comprise at least one flat tube unit, the flat tube unit comprising: a first flat tube inserted into the first flat tube slot; a second flat tube inserted into the second flat tube slot, the second flat tube being below the first flat tube; wherein along the width direction of the flat tube, the distance from the leeward end of the first flat tube to the windward side of the fin is W1, the distance from the leeward end of the second flat tube to the windward side of the fin is W2, and x=(W1-W2)>0. In the same flat tube unit, the vertical spacing distance between the first flat tube and the second flat tube is z, and a line S passing through the midpoint of the width direction of the first flat tube and parallel to the height direction is taken as a reference, the line S intersects the second flat tube; 15. The outdoor unit of the air conditioner according to claim 14, wherein In the same group of flat tube units, the width of the first flat tube is d1, the vertical spacing distance between the first flat tube and the second flat tube is z, 16. The outdoor unit of the air conditioner according to claim 14 or 15, wherein the distance t from the leeward end of the second flat tube to the line S satisfies: t≤0.16z. The flat tube comprises a third flat tube below the second flat tube, and the third flat tube has the same structure as the first flat tube; 17. The outdoor unit of the air conditioner according to any one of claims 14 to 16, wherein In the same group of flat tube units, the width of the first flat tube is d1, the vertical spacing distance between the first flat tube and the second flat tube is z, Fg = p w · g · V w p w is the water density, g is the gravitational acceleration, V w is the water droplet volume; p a is the air density, u a is the wind speed, A proj is the water droplet wind-facing area, Re D is the Reynolds number, a is the inclination angle of the water droplet's moving direction relative to the height direction of the fin, Fg is the gravity of the water droplet, Fa is the air drag force received by the water droplet, C D is the drag coefficient of the wind.

18. The outdoor unit of the air conditioner according to any one of claims 14 to 17, wherein the fin is provided with: a water guide portion, which protrudes from the surface of the fin or is in a slot shape, the water guide portion extending downward from a position close to the leeward end of the second flat tube, or the water guide portion extending obliquely from a position close to the leeward end of the second flat tube to the leeward end of the third flat tube. In a cross section of the heat exchanger that is orthogonal to the flow direction of the refrigerant, the farthest point of the leeward end of the second flat tube from the windward side of the fin is point A1, a line passing through point A1 and parallel to the height direction of the heat exchanger is line Q1, and the intersection point of line Q1 and the top end contour line of the second flat tube is point J1; 19. The outdoor unit of the air conditioner according to claim 18, wherein the farthest point of the leeward end of the third flat tube from the windward side of the fin is point A2, a line passing through point A2 and parallel to the height direction of the heat exchanger is line Q2, and the intersection point of line Q2 and the top end contour line of the third flat tube is point J2, and the line connecting point J1 and point J2 is line Q3; ​ The water guide part intersects with line Q1; the bottom end of the water guide part intersects with line Q3 or is located on the windward side of line Q3.

20. The outdoor unit of the air conditioner according to claim 18 or 19, wherein The vertical spacing distance between the second flat tube and the third flat tube is z, and the inclination angle β of the water guide part in the relative height direction satisfies: β≤arctan(x / z).

21. The outdoor unit of the air conditioner according to any one of claims 18 to 20, wherein The water guide part is connected with the fin at an angle γ, and γ<30°.

22. The outdoor unit of the air conditioner according to any one of claims 18 to 21, wherein The top end of the water guide part is spaced apart from the lower surface of the second flat tube by a distance L1, and the bottom end of the water guide part is spaced apart from the lower surface of the third flat tube by a distance L2, L1≤2mm, and L2≤2mm.

23. The outdoor unit of the air conditioner according to any one of claims 14 to 22, wherein The end surface of the leeward end of the flat tube comprises: an arc segment which is a curved surface, the arc segment being connected with the top surface of the flat tube; a straight line segment which is parallel to the height direction, the straight line segment being connected to the lower end of the arc segment.

24. The outdoor unit of the air conditioner according to any one of claims 14 to 23, wherein The distance from the windward end of the first flat tube to the windward side of the fin is y1, and the distance from the windward end of the second flat tube to the windward side of the fin is y2, and y1 and y2 satisfy: 0≤y1≤y2.

25. The outdoor unit of the air conditioner according to any one of claims 14 to 24, wherein A plurality of flow-through holes are arranged in the flat tube; in a cross section of the heat exchanger which is orthogonal to the flow direction of the refrigerant, the sum of the areas of the flow-through holes in the first flat tube is equal to the sum of the areas of the flow-through holes in the second flat tube.

26. The outdoor unit of the air conditioner according to any one of claims 14 to 25, wherein The distance from the windward end of the first flat tube and the windward end of the second flat tube to the windward side of the fin is equal, and the width d2 of the second flat tube satisfies: where d1 is the width of the first flat tube, z is the vertical spacing distance between the first flat tube and the second flat tube, and a is the inclination angle of the moving direction of the water droplets relative to the height direction of the fin.

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