Heat exchanger, outdoor unit having heat exchanger, and air conditioning device having outdoor unit

Abstract

The heat exchanger comprises: a heat exchange body having a plurality of flat tubes arranged at intervals in a horizontal direction; an upper header arranged at the upper end of the heat exchange body; a lower header arranged at the lower end of the heat exchange body; and a partition plate arranged inside at least one of the upper header and the lower header, and dividing the heat exchange body into a plurality of areas in the horizontal direction, the partition plate being arranged so that each area is in convection with the adjacent area, and being arranged so that the flow cross-sectional area of each area becomes smaller as the refrigerant flow moves from the upstream side to the downstream side when functioning as a condenser.

Description

Technical Field

[0001] The present disclosure relates to a heat exchanger including a plurality of flat tubes, an outdoor unit including the heat exchanger, and an air conditioning apparatus including the outdoor unit. Background Art

[0002] Conventionally, there has been a heat exchanger (e.g., see Patent Document 1) comprising: a plurality of flat tubes arranged horizontally at intervals with the vertical direction being the tube extension direction; a plurality of fins connected between adjacent flat tubes to conduct heat to the flat tubes; and headers disposed at the upper and lower ends of the plurality of flat tubes.

[0003] The heat exchanger described in Patent Document 1 is installed in the outdoor unit of an air conditioner capable of both cooling and heating operations. Furthermore, when heating is performed in a low-temperature environment where the outside air temperature is low and the surface temperature of the heat exchanger falls below 0°C, frost forms on the heat exchanger. Therefore, if the amount of frost on the heat exchanger exceeds a certain level, a defrost operation is performed to melt the frost on the heat exchanger surface. During the defrost operation, high-temperature, high-pressure gas refrigerant flows from one header and into the flat tubes, thereby defrosting the air.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-96638

[0005] In conventional heat exchangers such as those described in Patent Document 1, during defrost operation, the refrigerant flowing from the header is cooled as it flows through the flat tubes, with the liquid phase increasing as it moves downstream. This poses a problem: the refrigerant's flow rate decreases as the liquid phase increases, making it more likely for the refrigerant to flow backwards. This backflow of refrigerant can lead to reduced defrost performance. Summary of the Invention

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a heat exchanger capable of suppressing backflow of refrigerant, an outdoor unit including the heat exchanger, and an air-conditioning apparatus including the outdoor unit.

[0007] The heat exchanger involved in the present disclosure comprises: a heat exchange body having a plurality of flat tubes arranged at intervals in the horizontal direction; an upper header arranged at the upper end portion of the above-mentioned heat exchange body; a lower header arranged at the lower end portion of the above-mentioned heat exchange body; and a partition plate arranged inside at least one of the above-mentioned upper header and the above-mentioned lower header, and dividing the above-mentioned heat exchange body into a plurality of areas in the horizontal direction, the above-mentioned partition plate being arranged so that each of the above-mentioned areas is in convection with the above-mentioned adjacent areas, and being arranged so that the flow path cross-sectional area of each of the above-mentioned areas becomes smaller as the refrigerant flow moves from the upstream side to the downstream side when functioning as a condenser.

[0008] Furthermore, an outdoor unit of an air-conditioning apparatus according to the present disclosure includes the above-mentioned heat exchanger.

[0009] Furthermore, an air-conditioning apparatus according to the present disclosure includes the outdoor unit described above.

[0010] According to the heat exchanger, outdoor unit equipped with the heat exchanger, and air conditioner equipped with the outdoor unit of the present disclosure, the partition plate is arranged so that each region of the heat exchanger has countercurrent flow with adjacent regions, and is arranged so that the flow path cross-sectional area of each region decreases from the upstream side toward the downstream side of the refrigerant flow when functioning as a condenser. Thus, by reducing the flow path cross-sectional area of each region from the upstream side toward the downstream side of the refrigerant flow when functioning as a condenser, even if the liquid phase of the refrigerant increases, the flow velocity can be suppressed from decreasing, thereby suppressing backflow of the refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a refrigerant circuit diagram of an air-conditioning apparatus including the heat exchanger according to Embodiment 1.

[0012] Figure 2 It is a perspective view of the heat exchanger according to Embodiment 1.

[0013] Figure 3 This is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger according to Embodiment 1.

[0014] Figure 4 This is a diagram showing the flow path cross-sectional area of the flat tubes of the heat exchanger according to the first embodiment.

[0015] Figure 5 This is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger according to Embodiment 2.

[0016] Figure 6 This is a front view schematically showing the flow of refrigerant during the defrosting operation of the heat exchanger according to Embodiment 3.

[0017] Figure 7 yes Figure 6 The heat exchanger is shown in section AA.

[0018] Figure 8 yes Figure 6 The heat exchanger is shown in cross-section along line AA.

[0019] Figure 9 It is a front view schematically showing a bending region of the heat exchanger according to the fourth embodiment.

[0020] Figure 10It is a plan view schematically showing a bent region of a heat exchanger according to the fourth embodiment.

[0021] Figure 11 This is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger according to Embodiment 5.

[0022] Figure 12 This is a front view schematically showing the flow of refrigerant during the defrosting operation of the heat exchanger according to Embodiment 6.

[0023] Figure 13 It is a perspective view schematically showing the main parts of the heat exchanger according to the seventh embodiment.

[0024] Figure 14 It is a front view schematically showing the heat exchanger according to the seventh embodiment.

[0025] Figure 15 (a) to (e) are correct Figure 14 FIG. 1 is a diagram illustrating the positional relationship of the drainage slits on each fin surface of the corrugated fin shown in FIG.

[0026] Figure 16 These are diagrams explaining the flow of condensed water on the surfaces of the corrugated fins of the heat exchanger according to the seventh embodiment. DETAILED DESCRIPTION

[0027] The following describes embodiments of the present disclosure based on the accompanying drawings. The present disclosure is not limited to the embodiments described below. In the following drawings, the size relationships of the components may differ from the actual size relationships.

[0028] Implementation Method 1

[0029] <Structure of Air Conditioning Apparatus 100>

[0030] Figure 1 : is a refrigerant circuit diagram of the air-conditioning apparatus 100 including the heat exchanger 30 according to Embodiment 1. Figure 1 The solid arrows in the figure represent the flow of refrigerant during cooling operation. Figure 1 The dotted arrows in FIG. 1 represent the flow of the refrigerant during the heating operation.

[0031] like Figure 1 As shown, the heat exchanger 30 according to Embodiment 1 is mounted on the outdoor unit 10 of an air conditioning apparatus 100 including the outdoor unit 10 and the indoor unit 20. In addition to the heat exchanger 30, the outdoor unit 10 includes a compressor 11, a flow switching device 12, and a fan 13. The indoor unit 20 includes a throttle device 21, an indoor heat exchanger 22, and an indoor fan 23.

[0032] The air conditioner 100 also includes a refrigerant circuit that circulates refrigerant, connecting a compressor 11, a flow switching device 12, a heat exchanger 30, a throttle device 21, and an indoor heat exchanger 22 via refrigerant piping. The air conditioner 100 can perform both cooling and heating operations by switching the flow switching device 12.

[0033] The compressor 11 sucks in low-temperature, low-pressure refrigerant, compresses the sucked refrigerant, and discharges high-temperature, high-pressure refrigerant. The compressor 11 is, for example, an inverter compressor that controls the delivery volume per unit time, ie, capacity, by varying the operating frequency.

[0034] The flow switching device 12 is, for example, a four-way valve, which switches the direction of the refrigerant flow to switch between cooling operation and heating operation. Figure 1 The solid line shows the state that the discharge side of the compressor 11 and the heat exchanger 30 are connected. In addition, the flow switching device 12 is switched to use during the heating operation. Figure 1 The dotted line shows a state in which the discharge side of the compressor 11 and the indoor heat exchanger 22 are connected.

[0035] The heat exchanger 30 exchanges heat between the outdoor air and the refrigerant. During cooling operation, the heat exchanger 30 functions as a condenser, dissipating heat from the refrigerant to the outdoor air to condense the refrigerant. Furthermore, during heating operation, the heat exchanger 30 functions as an evaporator, evaporating the refrigerant and cooling the outdoor air using the heat of vaporization.

[0036] Fan 13 supplies outdoor air to heat exchanger 30 , and the amount of air supplied to heat exchanger 30 is adjusted by controlling the rotational speed.

[0037] The throttle device 21 is, for example, an electronic expansion valve whose throttle opening is adjustable. By adjusting the opening, the pressure of the refrigerant flowing into the heat exchanger 30 or the indoor heat exchanger 22 is controlled. In Embodiment 1, the throttle device 21 is provided in the indoor unit 20, but may also be provided in the outdoor unit 10, and the installation location is not limited.

[0038] The indoor heat exchanger 22 exchanges heat between the indoor air and the refrigerant. During cooling operation, the indoor heat exchanger 22 functions as an evaporator, evaporating the refrigerant and cooling the outdoor air using the heat of vaporization. Furthermore, during heating operation, the indoor heat exchanger 22 functions as a condenser, dissipating the refrigerant's heat to the outdoor air, condensing the refrigerant.

[0039] The indoor fan 23 supplies indoor air to the indoor heat exchanger 22 , and adjusts the amount of air supplied to the indoor heat exchanger 22 by controlling the rotation speed.

[0040] <Structure of Heat Exchanger 30>

[0041] Figure 2 It is a perspective view of the heat exchanger 30 according to Embodiment 1.

[0042] like Figure 2 As shown, the heat exchanger 30 includes a heat exchange body 31 having a plurality of flat tubes 38 and a plurality of fins 39. The flat tubes 38 are arranged horizontally and spaced apart so that the air generated by the fan 13 flows, and the refrigerant flows vertically within the tubes extending in the vertical direction. The fins 39 extend between adjacent flat tubes 38 and conduct heat to the flat tubes 38. The fins 39 improve the efficiency of heat exchange between the air and the refrigerant, and, for example, corrugated fins are used. However, this is not limiting. Since heat exchange between the air and the refrigerant occurs on the surface of the flat tubes 38, the fins 39 may not be present.

[0043] A lower header 34 is provided at the lower end of heat exchanger 31. The lower ends of flat tubes 38 of heat exchanger 31 are directly inserted into lower header 34. Furthermore, an upper header 35 is provided at the upper end of heat exchanger 31. The lower ends of flat tubes 38 of heat exchanger 31 are directly inserted into upper header 35.

[0044] The lower header 34 is connected to the gas pipe 37 (see the following description) Figure 3 ) and is connected to the refrigerant circuit of the air conditioning unit 100, and is also called a gas header. The lower header 34 allows the high-temperature, high-pressure gas refrigerant from the compressor 11 to flow into the heat exchanger 30 during cooling operation, and allows the low-temperature, low-pressure gas refrigerant, which has undergone heat exchange in the heat exchanger 30, to flow out of the refrigerant circuit during heating operation.

[0045] The upper header 35 is connected to the liquid pipe 36 (see the following description) Figure 3 ) and is connected to the refrigerant circuit of the air conditioning unit 100, and is also called a liquid header. The upper header 35 allows low-temperature, low-pressure two-phase refrigerant to flow into the heat exchanger 30 during heating operation, and allows low-temperature, high-pressure liquid refrigerant, which has undergone heat exchange in the heat exchanger 30, to flow out of the refrigerant circuit during cooling operation.

[0046] The plurality of flat tubes 38 , the fins 39 , the lower header 34 , and the upper header 35 are all made of aluminum and are joined together by brazing.

[0047] <Cooling operation>

[0048] The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the heat exchanger 30 through the flow switching device 12. The high-temperature, high-pressure gas refrigerant flowing into the heat exchanger 30 condenses while exchanging heat with the outdoor air drawn in by the fan 13, releasing heat, and then flows out of the heat exchanger 30. The low-temperature, high-pressure liquid refrigerant flowing out of the heat exchanger 30 is decompressed by the throttle device 21, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which then flows into the indoor heat exchanger 22. The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing into the indoor heat exchanger 22 evaporates while exchanging heat with the indoor air drawn in by the indoor fan 23, absorbing heat, cooling the indoor air and becoming a low-temperature, low-pressure gas refrigerant, which then flows out of the indoor heat exchanger 22. The low-temperature, low-pressure gas refrigerant flowing out of the indoor heat exchanger 22 is drawn into the compressor 11, where it again becomes a high-temperature, high-pressure gas refrigerant.

[0049] <Heating operation>

[0050] The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 flows into the indoor heat exchanger 22 via the flow switching device 12. The high-temperature, high-pressure gas refrigerant flowing into the indoor heat exchanger 22 exchanges heat with the indoor air drawn in by the indoor fan 23, releasing heat while condensing, heating the indoor air and becoming a low-temperature, high-pressure liquid refrigerant, which then flows out of the indoor heat exchanger 22. The low-temperature, high-pressure liquid refrigerant flowing out of the indoor heat exchanger 22 is decompressed by the throttle device 21, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, which then flows into the heat exchanger 30. The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing into the heat exchanger 30 exchanges heat with the outdoor air drawn in by the fan 13, absorbing heat while evaporating, becoming a low-temperature, low-pressure gas refrigerant, and flowing out of the heat exchanger 30. The low-temperature, low-pressure gas refrigerant flowing out of the heat exchanger 30 is drawn into the compressor 11 and becomes a high-temperature, high-pressure gas refrigerant again.

[0051] <Defrosting operation>

[0052] When heating is performed in a low-temperature environment where the surface temperature of the flat tubes 38 and fins 39 falls below 0°C, frost forms on the heat exchanger 30. If the amount of frost on the heat exchanger 30 exceeds a certain level, the air passage through the heat exchanger 30, through which air from the fan 13 passes, becomes blocked, reducing the performance of the heat exchanger 30 and the heating performance. Therefore, when heating performance decreases, a defrost operation is performed to melt the frost on the surface of the heat exchanger 30.

[0053] During the defrost operation, the fan 13 stops, and the flow switching device 12 switches to the same state as during the cooling operation, and the high-temperature and high-pressure gas refrigerant flows into the heat exchanger 30. As a result, the frost attached to the flat tubes 38 and the fins 39 melts. If the defrost operation starts, the high-temperature and high-pressure gas refrigerant flows into each flat tube 38 through the lower header 34. Then, the frost attached to the flat tubes 38 and the fins 39 is melted by the high-temperature refrigerant flowing into the flat tubes 38 and turned into water. The water generated by the melting of the frost (hereinafter referred to as defrost water) is discharged to the bottom of the heat exchanger 30 along the flat tubes 38 or the fins 39. If the attached frost has melted, the defrost operation ends and the heating operation starts again.

[0054] During defrost operation, the refrigerant flowing in from the lower header 34 is cooled as it flows through the flat tubes 38, and the liquid phase increases as it moves downstream. As the liquid phase increases, the refrigerant's flow rate decreases, making it more likely for the refrigerant to flow back. This backflow has previously led to reduced defrost performance.

[0055] Figure 3 : is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger 30 according to the first embodiment. Figure 3 The hollow arrows and black dotted arrows in FIG. 8 represent the flow of the refrigerant.

[0056] In the heat exchanger 30 according to the first embodiment, Figure 3 As shown, partition plates 40 are provided on lower header 34 and upper header 35. These partition plates 40 are provided to horizontally partition heat exchanger 31 into a plurality of zones. Furthermore, partition plates 40 are positioned so that each zone of heat exchanger 31 is counter-current flow-produced with adjacent zones, and so that the flow path cross-sectional area of each zone of heat exchanger 31 decreases as it moves from the upstream side toward the downstream side of the refrigerant flow when functioning as a condenser (hereinafter referred to as the defrost refrigerant flow).

[0057] In Embodiment 1, one partition plate 40 is provided in each of the lower header 34 and the upper header 35. That is, a total of two partition plates 40 are provided. Furthermore, the number of partition plates 40 is not limited to two and may be one or three or more. Furthermore, the heat exchanger 31 is divided into three regions by the partition plates 40: specifically, a first region 311, a second region 312, and a third region 313. During defrosting, the first region 311 is the most upstream region, and the third region 313 is the most downstream region in the refrigerant flow.

[0058] Moreover, if Figure 3As shown, in the first area 311 and the third area 313 of the heat exchanger 31, the refrigerant flows vertically upward, i.e., upward flow, and in the second area 312 of the heat exchanger 31, the refrigerant flows vertically downward, i.e., downward flow. Therefore, each area of the heat exchanger 31 is formed to form a countercurrent with the adjacent area. Here, as the refrigerant flow during the defrosting operation, Figure 3 As shown by the arrows, the order is gas piping 37, lower header 34, first region 311 of heat exchanger 31, upper header 35, second region 312 of heat exchanger 31, lower header 34, third region 313 of heat exchanger 31, upper header 35, and liquid piping 36.

[0059] Furthermore, the horizontal lengths of first region 311, second region 312, and third region 313 of heat exchanger 31 are L1, L2, and L3, respectively, with L1 > L2 > L3. Therefore, first region 311 of heat exchanger 31 has the largest number of flat tubes 38 and the largest flow path cross-sectional area. Third region 313 of heat exchanger 31 has the smallest number of flat tubes 38 and the smallest flow path cross-sectional area. In other words, the flow path cross-sectional area of each region of heat exchanger 31 decreases as one moves from the upstream side of the refrigerant flow toward the downstream side during defrosting.

[0060] Thus, in Embodiment 1, during defrosting, for the same refrigerant flow rate as the upstream side, the flow path cross-sectional area in the downstream region is made smaller than that in the upstream region, thereby enabling the flow velocity in the downstream region to be faster than that in the upstream region. Therefore, even if the refrigerant increases in the downstream liquid phase, backflow can be suppressed, thereby minimizing the reduction in defrosting performance caused by backflow of the refrigerant.

[0061] Furthermore, when heat exchanger 30 functions as a condenser and the region on the most downstream side of heat exchanger 31 is experiencing an upward flow, the refrigerant flow in the region on the most downstream side of heat exchanger 31 experiencing an upward flow (hereinafter referred to as region Z) has a flooding constant C greater than 1. Here, flooding constant C is defined based on the refrigerant flow rate into region Z when heat exchanger 30 functions as a condenser and operates at an intermediate load capacity (50% capacity).

[0062] The overflow constant C is defined as C=J using the generally known Wallis formula. G 0.5 +J L 0.5 .

[0063] Here, J G is the dimensionless gas superficial velocity, J Lis the dimensionless liquid superficial velocity and is defined as follows.

[0064] J G =U G ×{ρ G / [9.81×D eq (ρ L -ρ G )]} 0.5

[0065] J L =U L ×{ρ L / [9.81×D eq (ρ L -ρ G )]} 0.5

[0066] Figure 4 This is a diagram showing the flow path cross-sectional area of the flat tubes 38 of the heat exchanger 30 according to the first embodiment.

[0067] D eq The number N of flat tubes 38 arranged in the area Z and the flow path cross-sectional area A1 ( Figure 4 The equivalent diameter [m] is defined by the sum of the oblique line parts of eq =[(4×A eq ) / 3.14] 0.5 Calculate. Here, by A eq =A1×N is calculated.

[0068] ρ L is the liquid density of the refrigerant [kg / m 3 ],ρ G is the gas density of the refrigerant [kg / m 3 ] are state quantities that can be calculated based on the type and pressure of the refrigerant flowing into the heat exchanger 30.

[0069] U G is the gas superficial velocity [m / s], U L is the liquid superficial velocity [m / s], through U G =(G×x) / ρ G 、U L =[G×(1-x)] / ρ L Figure it out.

[0070] If G is the maximum flow rate of the high-temperature and high-pressure gas refrigerant flowing into the heat exchanger 30 [kg / m 2 s], M is the maximum flow rate [kg / s] of the high-temperature and high-pressure gas refrigerant flowing into the heat exchanger 30, then G=M / A eq Figure it out.

[0071] X represents the dryness of the refrigerant flowing into zone Z, and can be calculated based on, for example, the heat exchange rate or heat exchange performance of the heat exchanger 30. For example, assuming that the refrigerant dryness varies from 1 to 0 between the inlet and outlet of the heat exchanger 30, and assuming that the heat exchange rate ∝ the heat transfer area, the dryness can be estimated by the ratio of the number of flat tubes 38 arranged in the zone upstream of zone Z to the total number of flat tubes 38 in the heat exchanger 30. For example, in Embodiment 1, x can be defined as 1 - (number of flat tubes in the first zone + number of flat tubes in the second zone) / (number of flat tubes in the first zone + number of flat tubes in the second zone + number of flat tubes in the third zone).

[0072] Thus, heat exchanger 30 is configured such that, when functioning as a condenser, when the downstream-most region of heat exchanger 31 is in an upflow state, the refrigerant flow in region Z of heat exchanger 31 is such that an overflow constant C>1. Therefore, when heat exchanger 30 functions as a condenser, even when the downstream-most region of heat exchanger 31 is in an upflow state, backflow of the refrigerant can be more reliably suppressed.

[0073] As described above, heat exchanger 30 according to Embodiment 1 includes: heat exchanger 31 having a plurality of flat tubes 38 arranged horizontally at intervals; upper header 35 provided at the upper end of heat exchanger 31; and lower header 34 provided at the lower end of heat exchanger 31. Heat exchanger 30 also includes partition plate 40, which is provided within at least one of upper header 35 and lower header 34 and divides heat exchanger 31 into a plurality of zones in the horizontal direction. Partition plate 40 is arranged so that each zone has countercurrent flow with adjacent zones, and so that the flow cross-sectional area of each zone decreases as the refrigerant flow moves from upstream to downstream when functioning as a condenser.

[0074] In heat exchanger 30 according to Embodiment 1, partition plate 40 is arranged so that each region of heat exchange element 31 creates countercurrent flow with adjacent regions, and is also arranged so that the flow path cross-sectional area of each region decreases as the refrigerant flows from upstream to downstream when functioning as a condenser. Thus, by decreasing the flow path cross-sectional area of each region as the refrigerant flows from upstream to downstream when functioning as a condenser, even if the amount of liquid phase of the refrigerant increases, a decrease in flow velocity can be suppressed, thereby preventing backflow of the refrigerant.

[0075] Furthermore, the outdoor unit 10 according to Embodiment 1 includes the above-described heat exchanger 30. According to the outdoor unit 10 according to Embodiment 1, the same effects as those of the above-described heat exchanger 30 can be obtained.

[0076] Furthermore, the air conditioning apparatus 100 according to Embodiment 1 includes the outdoor unit 10 described above. According to the air conditioning apparatus 100 according to Embodiment 1, the same effects as those of the outdoor unit 10 described above can be obtained.

[0077] Implementation Method 2

[0078] Hereinafter, the second embodiment will be described, but descriptions of portions overlapping with those of the first embodiment will be omitted, and portions identical to or corresponding to those of the first embodiment will be denoted by the same reference numerals.

[0079] Figure 5 : is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger 30 according to the second embodiment. Figure 5 The hollow arrows and black dotted arrows in FIG. 8 represent the flow of the refrigerant.

[0080] In the heat exchanger 30 according to the second embodiment, Figure 5 As shown, two partition plates 40 are provided in the lower header 34 and one in the upper header 35. That is, a total of three partition plates 40 are provided. Furthermore, the heat exchanger 31 is divided into four regions by the partition plates 40: specifically, a first region 311, a second region 312, a third region 313, and a fourth region 314. However, the number of partition plates 40 is not limited to three; any odd number of five or more may be used.

[0081] The most upstream portion of the refrigerant flow during defrosting of the lower header 34 (hereinafter referred to as the first portion 341) is connected to the refrigerant circuit of the air conditioning apparatus 100 via the gas piping 37. The first portion 341 of the lower header 34 allows the high-temperature, high-pressure gas refrigerant from the compressor 11 to flow into the heat exchanger 30 during cooling operation, and allows the low-temperature, low-pressure gas refrigerant, which has undergone heat exchange in the heat exchanger 30, to flow out of the refrigerant circuit during heating operation.

[0082] The lower header 34 has a portion (hereinafter referred to as the second portion 342) on the most downstream side of the refrigerant flow during defrosting, connected to the upper header 35 via the liquid pipe 36 to the refrigerant circuit of the air conditioner 100. The second portion 342 of the lower header 34 allows low-temperature, low-pressure two-phase refrigerant to flow into the heat exchanger 30 during heating operation, and allows low-temperature, high-pressure liquid refrigerant, which has undergone heat exchange in the heat exchanger 30, to flow out of the refrigerant circuit during cooling operation.

[0083] Moreover, if Figure 5As shown, in the first area 311 and the third area 313 of the heat exchanger 31, the refrigerant flows in an upward flow, and in the second area 312 and the fourth area 314 of the heat exchanger 31, the refrigerant flows in a downward flow. Therefore, each area of the heat exchanger 31 is formed to form a countercurrent with the adjacent area. Here, as the refrigerant flow during the defrosting operation, Figure 5 As shown by the arrows, the order is the gas piping 37, the lower header 34, the first area 311 of the heat exchanger 31, the upper header 35, the second area 312 of the heat exchanger 31, the lower header 34, the third area 313 of the heat exchanger 31, the upper header 35, the fourth area 314 of the heat exchanger 31, the lower header 34, and the liquid piping 36.

[0084] Furthermore, the horizontal lengths of first region 311, second region 312, third region 313, and fourth region 314 of heat exchanger 31 are L1, L2, L3, and L4, respectively, with L1 > L2 > L3 > L4. Therefore, first region 311 of heat exchanger 31 has the largest number of flat tubes 38 and the largest flow path cross-sectional area. Meanwhile, fourth region 314 of heat exchanger 31 has the smallest number of flat tubes 38 and the smallest flow path cross-sectional area. In other words, the flow path cross-sectional area of each region of heat exchanger 31 decreases as one moves from the upstream side of the refrigerant flow toward the downstream side during defrosting.

[0085] In this way, during defrosting, the refrigerant flow in the fourth region 314, the most downstream region of the heat exchanger 31, is made a downward flow. This prevents backflow even if the refrigerant increases in the downstream liquid phase. Furthermore, for the same refrigerant flow rate as the upstream, the flow path cross-sectional area in the downstream region is smaller than that on the upstream side, allowing the flow velocity to be faster in the downstream region than in the upstream region. Consequently, even if the refrigerant increases in the downstream liquid phase, backflow can be further prevented, further minimizing the degradation of defrosting performance caused by backflow.

[0086] As described above, when the heat exchanger 30 according to Embodiment 2 functions as a condenser, the refrigerant flowing in the most downstream region is a downflow.

[0087] According to the heat exchanger 30 according to Embodiment 2, when functioning as a condenser, the refrigerant flowing in the most downstream region is a downflow. Therefore, even if the refrigerant increases in liquid phase as it moves downstream, backflow can be suppressed.

[0088] Furthermore, the outdoor unit 10 according to Embodiment 2 includes the above-described heat exchanger 30. According to the outdoor unit 10 according to Embodiment 2, the same effects as those of the above-described heat exchanger 30 can be obtained.

[0089] Furthermore, the air conditioning apparatus 100 according to Embodiment 2 includes the outdoor unit 10 described above. According to the air conditioning apparatus 100 according to Embodiment 2, the same effects as those of the outdoor unit 10 described above can be obtained.

[0090] Implementation 3

[0091] Hereinafter, Embodiment 3 will be described, but descriptions of portions overlapping with those in Embodiment 2 will be omitted, and portions identical to or corresponding to those in Embodiment 2 will be denoted by the same reference numerals.

[0092] Figure 6 This is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger 30 according to the third embodiment. Figure 7 yes Figure 6 The heat exchanger 30 is shown in cross-section AA. Figure 6 The hollow arrows and black dotted arrows in FIG. 8 represent the flow of the refrigerant.

[0093] In the heat exchanger 30 according to the third embodiment, Figure 6 and Figure 7 As shown, an extension pipe 33 is provided along the longitudinal direction of the lower header 34 .

[0094] Furthermore, at least a portion of the extension pipe 33 contacts the lower header 34. Furthermore, the extension pipe 33 is disposed below the lower header 34. Furthermore, the lower header 34 is connected to the liquid pipe 36, and the extension pipe 33 is connected to the gas pipe 37. Furthermore, an opening 44 is formed at the contact portion between the extension pipe 33 and the lower header 34, thereby connecting the extension pipe 33 and the lower header 34. This opening 44 is formed below the first region 311 of the heat exchanger 31.

[0095] As the refrigerant flow during defrost operation, Figure 6 As shown by the arrows, the order is the gas piping 37, the extension piping 33, the lower header 34, the first area 311 of the heat exchanger 31, the upper header 35, the second area 312 of the heat exchanger 31, the lower header 34, the third area 313 of the heat exchanger 31, the upper header 35, the fourth area 314 of the heat exchanger 31, the lower header 34, and the liquid piping 36.

[0096] In Embodiment 3, the extension pipe 33 is arranged parallel to the lower header 34, with at least a portion of it in contact with the lower header 34. Furthermore, the extension pipe 33 is positioned below the lower header 34. This contact between at least a portion of the extension pipe 33 and the lower header 34 allows heat from the extension pipe 33, where high-temperature, high-pressure gas refrigerant flows, to be transferred to the lower header 34 during defrost operation. The heat transferred to the lower header 34 is then transferred to the defrosted water near the lower header 34, raising the temperature of the defrosted water. Therefore, even after the defrost operation ends and heating operation resumes, the defrosted water near the lower header 34 is prevented from refreezing. Consequently, a decrease in heating capacity and damage to the heat exchanger 30 can be suppressed. Furthermore, the extension pipe 33's placement below the lower header 34 prevents obstruction of the defrosted water's drainage path, thereby preventing deterioration in drainage performance.

[0097] Figure 8 yes Figure 6 The heat exchanger 30 is shown in cross section along line AA of a modified example.

[0098] In the third embodiment, the extension pipe 33 is provided separately from the lower header 34. However, the extension pipe 33 may be formed integrally with the lower header 34. As a modified example of this case, Figure 8 As shown, a second partition plate 41 is provided inside the lower header 34 to vertically partition the interior. Consequently, a first flow path 42 on the upper side and a second flow path 43 on the lower side are formed inside the lower header 34. Furthermore, the upper portion of the lower header 34 is connected to the liquid pipe 36, and the first flow path 42 communicates with the liquid pipe 36. Furthermore, the lower portion of the lower header 34 is connected to the gas pipe 37, and the second flow path 43 communicates with the gas pipe 37. In other words, the portion of the lower header 34 that forms the second flow path 43 corresponds to the extension pipe 33 in Embodiment 3, and the portion of the lower header 34 that forms the second flow path 43 corresponds to the lower header 34 in Embodiment 3.

[0099] Thus, in the heat exchanger 30 according to the modified example of Embodiment 3, the second flow path 43 of the lower header 34 is formed parallel to the first flow path 42 of the lower header 34. The second flow path 43 is formed adjacent to the first flow path 42 via the second partition plate 41. Therefore, during defrost operation, heat from the second flow path 43 of the lower header 34, where high-temperature, high-pressure gas refrigerant flows, can be transferred to the first flow path 42 of the lower header 34 via the second partition plate 41. The heat transferred to the first flow path 42 of the lower header 34 is then transferred to the defrosted water near the lower header 34, raising the temperature of the defrosted water. Therefore, even after the defrost operation ends and heating operation resumes, the defrosted water near the lower header 34 is prevented from refreezing. As a result, a decrease in heating capacity and damage to the heat exchanger 30 can be suppressed. Furthermore, the second flow passage 43 of the lower header 34 is disposed below the first flow passage 42 of the lower header 34 and does not obstruct the drainage path of the defrost water, thereby preventing deterioration in drainage performance.

[0100] As described above, the heat exchanger 30 according to Embodiment 3 includes an extension pipe 33. When functioning as an evaporator, the extension pipe 33 allows refrigerant to flow out, and when functioning as a condenser, the extension pipe 33 allows refrigerant to flow in. Furthermore, the extension pipe 33 is provided along the longitudinal direction of the lower header 34, and at least a portion thereof is in contact with the lower header 34.

[0101] In the heat exchanger 30 according to Embodiment 3, at least a portion of the extension pipe 33 contacts the lower header 34. This allows heat from the extension pipe 33, through which high-temperature, high-pressure gas refrigerant flows, to be transferred to the lower header 34 during defrost operation. The heat transferred to the lower header 34 is then transferred to the defrosted water near the lower header 34, raising the temperature of the defrosted water. Therefore, even after the defrost operation is completed and heating operation resumes, the defrosted water near the lower header 34 is prevented from refreezing. Consequently, a decrease in heating capacity and damage to the heat exchanger 30 can be suppressed.

[0102] Furthermore, the outdoor unit 10 according to Embodiment 3 includes the above-described heat exchanger 30. According to the outdoor unit 10 according to Embodiment 3, the same effects as those of the above-described heat exchanger 30 can be obtained.

[0103] Furthermore, the air-conditioning apparatus 100 according to Embodiment 3 includes the outdoor unit 10 described above. According to the air-conditioning apparatus 100 according to Embodiment 3, the same effects as those of the outdoor unit 10 described above can be obtained.

[0104] Implementation 4

[0105] Hereinafter, the fourth embodiment will be described, but descriptions of portions overlapping with those of the second embodiment will be omitted, and portions identical to or corresponding to those of the second embodiment will be denoted by the same reference numerals.

[0106] Figure 9 It is a front view schematically showing a bent region 50 of a heat exchanger 30 according to the fourth embodiment. Figure 10 It is a plan view schematically showing a bent region 50 of a heat exchanger 30 according to the fourth embodiment.

[0107] The heat exchanger 30 may be bent for reasons such as high density mounting on the outdoor unit 10 to improve heat exchange performance and miniaturization of the outdoor unit 10. Figure 9 and Figure 10 Bending is performed within the bending region 50 shown. If the partition plate 40 is provided within the bending region 50, the partition plate 40 would deform during the bending of the heat exchanger 30, resulting in a decrease in heat exchange performance. Therefore, in Embodiment 4, the partition plate 40 is not provided within the bending region 50, but rather is provided outside the bending region 50. By providing the partition plate 40 outside the bending region 50, the partition plate 40 does not deform even when the heat exchanger 30 is bent, thereby improving heat exchange performance and reducing the size of the outdoor unit 10 while suppressing a decrease in heat exchange performance.

[0108] As described above, in the heat exchanger 30 according to the fourth embodiment, the upper header 35 and the lower header 34 have the bent regions 50 , and the partition plate 40 is arranged in the region excluding the bent regions 50 .

[0109] According to the heat exchanger 30 of Embodiment 4, the partition plate 40 is disposed outside the bent region 50. Therefore, even when the heat exchanger 30 is bent, the partition plate 40 does not deform. Consequently, heat exchange performance can be improved, the outdoor unit 10 can be downsized, and degradation of heat exchange performance can be suppressed.

[0110] Furthermore, the outdoor unit 10 according to Embodiment 4 includes the above-described heat exchanger 30. According to the outdoor unit 10 according to Embodiment 4, the same effects as those of the above-described heat exchanger 30 can be obtained.

[0111] Furthermore, the air-conditioning apparatus 100 according to Embodiment 4 includes the outdoor unit 10 described above. According to the air-conditioning apparatus 100 according to Embodiment 4, the same effects as those of the outdoor unit 10 described above can be obtained.

[0112] Implementation 5

[0113] Hereinafter, the fifth embodiment will be described, but descriptions of portions overlapping with those of the second embodiment will be omitted, and portions identical to or corresponding to those of the second embodiment will be denoted by the same reference numerals.

[0114] Figure 11 : is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger 30 according to the fifth embodiment. Figure 11 The hollow arrows and black dotted arrows in FIG. 8 represent the flow of the refrigerant.

[0115] In the heat exchanger 30 according to the fifth embodiment, Figure 11 As shown, the heat exchanger 30 has multiple heat exchange sections. Specifically, the heat exchanger 30 includes a first heat exchange section 30a and a second heat exchange section 30b. The first heat exchange section 30a includes a first heat exchanger 31a having a plurality of flat tubes 38 and a plurality of fins 39; a first lower header 34a disposed at the lower end of the first heat exchanger 31a; and a first upper header 35a disposed at the upper end of the first heat exchanger 31a. Furthermore, the second heat exchange section 30b includes a second heat exchanger 31b having a plurality of flat tubes 38 and a plurality of fins 39; a second lower header 34b disposed at the lower end of the second heat exchanger 31b; and a second upper header 35b disposed at the upper end of the second heat exchanger 31b.

[0116] The first lower header 34a is connected to the refrigerant circuit of the air conditioning apparatus 100 via the gas piping 37. The first lower header 34a allows the high-temperature, high-pressure gas refrigerant from the compressor 11 to flow into the heat exchanger 30 during cooling operation, and allows the low-temperature, low-pressure gas refrigerant, which has undergone heat exchange in the heat exchanger 30, to flow out of the refrigerant circuit during heating operation.

[0117] The second lower header 34b is connected to the refrigerant circuit of the air conditioning apparatus 100 via the liquid pipe 36. The second lower header 34b allows low-temperature, low-pressure two-phase refrigerant to flow into the heat exchanger 30 during heating operation, and allows low-temperature, high-pressure liquid refrigerant, which has undergone heat exchange in the heat exchanger 30, to flow out of the refrigerant circuit during cooling operation.

[0118] Furthermore, the first upper header 35a and the second upper header 35b are connected and communicated by a connecting pipe 60. Alternatively, instead of the first upper header 35a and the second upper header 35b, the first lower header 34a and the second lower header 34b may be connected and communicated by a connecting pipe 60. In this case, in Embodiment 5, the gas pipe 37 is connected to the first upper header 35a, and the liquid pipe 36 is connected to the second lower header 34b.

[0119] Furthermore, a partition plate 40 is provided in the second heat exchange section 30b. One partition plate 40 is provided in each of the second lower header 34b and the second upper header 35b. In other words, two partition plates 40 are provided in total. Furthermore, the second heat exchanger 31b is divided into three regions by the partition plates 40: specifically, a first region 31b1, a second region 31b2, and a third region 31b3. However, the number of partition plates 40 is not limited to two and may be one, or three or more. Furthermore, no partition plate 40 is provided in the first heat exchange section 30a.

[0120] Moreover, if Figure 11 As shown, in the first area 31b1 and the third area 31b3 of the second heat exchanger 31b, the flow of the refrigerant becomes an upward flow, and in the second area 31b2 of the second heat exchanger 31b, the flow of the refrigerant becomes a downward flow. In addition, in the first heat exchanger 31a, the flow of the refrigerant becomes an upward flow. Therefore, each area of the heat exchanger 31 is formed to form a countercurrent with the adjacent area. Here, as the flow of the refrigerant during the defrosting operation, Figure 11 As shown by the arrows, the order is the gas piping 37, the first lower header 34a, the first heat exchanger 31a, the first upper header 35a, the connecting pipe 60, the first area 35b1 of the second upper header 35b, the first area 31b1 of the second heat exchanger 31b, the first flow path 34b1 of the second lower header 34b, the second area 31b2 of the second heat exchanger 31b, the second area 35b2 of the second upper header 35b, the third area 31b3 of the second heat exchanger 31b, the second flow path 34b2 of the second lower header 34b, and the liquid piping 36.

[0121] Furthermore, the horizontal lengths of the first region 31b1, second region 31b2, and third region 31b3 of the first heat exchanger 31a and second heat exchanger 31b are L1, L2, L3, and L4, respectively, with L1 > L2 > L3 > 4. Therefore, the first heat exchanger 31a has the largest number of flat tubes 38 and the largest flow path cross-sectional area. Meanwhile, the third region 31b3 of the second heat exchanger 31b has the smallest number of flat tubes 38 and the smallest flow path cross-sectional area. In other words, the flow path cross-sectional area of each region of the first heat exchanger 31a and second heat exchanger 31b decreases as one moves from the upstream side of the refrigerant flow toward the downstream side during defrosting.

[0122] Thus, during defrosting, for the same refrigerant flow rate as the upstream, the flow path cross-sectional area is smaller in the downstream region than in the upstream region, allowing the flow velocity in the downstream region to be faster than that in the upstream region. Therefore, even if the refrigerant increases in the downstream liquid phase, backflow can be suppressed, thereby minimizing the deterioration of defrosting performance caused by backflow of refrigerant.

[0123] Furthermore, by dividing the heat exchanger 30 into a first heat exchange section 30a and a second heat exchange section 30b and connecting them with the connecting pipe 60, the heat exchanger 30 can be easily bent. Furthermore, since the first heat exchange section 30a and the second heat exchange section 30b are connected, the gas pipe 37 only needs to be connected to the header of one of the first heat exchange section 30a and the second heat exchange section 30b. This reduces the space required for routing the piping, allows the heat exchanger 30 to be installed in the outdoor unit 10 at a high density, and improves heat exchange performance.

[0124] Furthermore, the heat exchanger 30 according to Embodiment 5 has two heat exchange sections, but the present invention is not limited thereto and may have three or more heat exchange sections. When the heat exchanger 30 has three or more heat exchange sections, the upper headers or lower headers of adjacent heat exchange sections are connected by connecting pipes 60, so that the adjacent heat exchange sections communicate with each other through the upper headers or lower headers.

[0125] As described above, in the heat exchanger 30 according to Embodiment 5, the heat exchanger 31 includes a first heat exchanger 31a and a second heat exchanger 31b. Furthermore, the upper header 35 includes a first upper header 35a disposed at the upper end of the first heat exchanger 31a and a second upper header 35b disposed at the upper end of the second heat exchanger 31b. Furthermore, the lower header 34 includes a first lower header 34a disposed at the lower end of the first heat exchanger 31a and a second lower header 34b disposed at the lower end of the second heat exchanger 31b. Furthermore, the first upper header 35a and the second upper header 35b, or the first lower header 34a and the second lower header 34b, are connected and communicated by a connecting pipe 60.

[0126] In the heat exchanger 30 according to Embodiment 5, the first upper header 35a and the second upper header 35b, or the first lower header 34a and the second lower header 34b, are connected and communicated by the connecting pipe 60, making bending of the heat exchanger 30 easy. Furthermore, since the first heat exchange section 30a and the second heat exchange section 30b are connected, the gas pipe 37 only needs to be connected to the header of one of the first heat exchange section 30a and the second heat exchange section 30b. This reduces the space required for routing the piping, allows the heat exchanger 30 to be installed in the outdoor unit 10 at a high density, and improves heat exchange performance.

[0127] Furthermore, the outdoor unit 10 according to Embodiment 5 includes the above-described heat exchanger 30. According to the outdoor unit 10 according to Embodiment 5, the same effects as those of the above-described heat exchanger 30 can be obtained.

[0128] Furthermore, the air-conditioning apparatus 100 according to Embodiment 5 includes the outdoor unit 10 described above. According to the air-conditioning apparatus 100 according to Embodiment 5, the same effects as those of the outdoor unit 10 described above can be obtained.

[0129] Implementation Method 6

[0130] Hereinafter, the sixth embodiment will be described, but descriptions of portions overlapping with those of the fifth embodiment will be omitted, and portions identical to or corresponding to those of the fifth embodiment will be denoted by the same reference numerals.

[0131] Figure 12 This is a front view schematically showing the flow of the refrigerant during the defrosting operation of the heat exchanger 30 according to the sixth embodiment.

[0132] In the heat exchanger 30 according to the sixth embodiment, Figure 12 As shown, the first heat exchanger 31a and the second heat exchanger 31b have different lengths in the vertical direction, with the first heat exchanger 31a being longer than the second heat exchanger 31b. Furthermore, the first heat exchanger 31a is positioned at the same height as the second heat exchanger 31b, or the first heat exchanger 31a is positioned higher than the second heat exchanger 31b.

[0133] Furthermore, the first upper header 35a and the second upper header 35b are connected by a connecting pipe 60 so as to communicate with each other.

[0134] In this way, during defrosting, the refrigerant flowing in the connecting pipe 60 becomes a downward flow or a horizontal flow, i.e., a horizontal flow. Therefore, it is possible to suppress the backflow caused by the refrigerant flowing in the connecting pipe 60 becoming an upward flow, and to suppress the reduction in defrosting performance caused by the backflow of the refrigerant.

[0135] Furthermore, while the heat exchanger 30 according to Embodiment 6 includes two heat exchange sections, the present invention is not limited thereto and may include three or more heat exchange sections. When the heat exchanger 30 includes three or more heat exchange sections, the upper headers or lower headers of adjacent heat exchange sections are connected by connecting pipes 60 . The upper or lower headers allow the adjacent heat exchange sections to communicate with each other, and during defrosting, the refrigerant flowing through each connecting pipe 60 is configured to flow downward or horizontally.

[0136] As described above, in heat exchanger 30 according to Embodiment 6, first heat exchanger 31a and second heat exchanger 31b have different lengths, and when functioning as a condenser, the refrigerant flowing through connecting pipe 60 is a downward flow or a horizontal flow.

[0137] According to the heat exchanger 30 of Embodiment 6, when functioning as a condenser, the refrigerant flowing through the connecting pipe 60 is a downward flow or a horizontal flow, i.e., a horizontal flow. Therefore, it is possible to suppress a reverse flow caused by the refrigerant flowing through the connecting pipe 60 becoming an upward flow, thereby suppressing a reduction in defrosting performance caused by the reverse flow of the refrigerant.

[0138] Furthermore, the outdoor unit 10 according to Embodiment 6 includes the above-described heat exchanger 30. According to the outdoor unit 10 according to Embodiment 6, the same effects as those of the above-described heat exchanger 30 can be obtained.

[0139] Furthermore, the air conditioning apparatus 100 according to Embodiment 6 includes the outdoor unit 10 described above. According to the air conditioning apparatus 100 according to Embodiment 6, the same effects as those of the outdoor unit 10 described above can be obtained.

[0140] Implementation 7

[0141] Hereinafter, Embodiment 7 will be described, but descriptions of portions overlapping with those of Embodiments 1 to 6 will be omitted, and portions identical to or corresponding to those of Embodiments 1 to 6 will be denoted by the same reference numerals.

[0142] Figure 13 It is a perspective view schematically showing a main part of a heat exchanger 30 according to the seventh embodiment.

[0143] like Figure 13 As shown, the heat exchanger 30 involved in embodiment 7 has a plurality of flat tubes 38 and a plurality of corrugated fins 39a. The corrugated fins 39a are formed in a wave shape and have a plurality of tops 390. Except for one end portion protruding toward the upstream side in the air flow direction (hereinafter referred to as the first direction) between adjacent flat tubes 38, each top 390 is in surface contact with the flat surface of the flat tube 38. In addition, the corrugated fins 39a and the flat tubes 38 are joined by brazing. The corrugated fins 39a are made of, for example, an aluminum alloy plate. Moreover, a brazing material layer is laminated on the surface of the plate, and the brazing material layer is formed of, for example, a brazing material containing aluminum of an aluminum silicon type. In addition, the plate thickness is about 50μm to 200μm.

[0144] The corrugated fins 39a have fin surfaces 350 between adjacent top portions 390 along the arrangement direction of the flat tubes 38 (hereinafter referred to as the second direction), with each fin surface 350 arranged along the height direction. Furthermore, each fin surface 350 has louvers 360 and drainage slits 370. Multiple louvers 360 are arranged along the first direction of each fin surface 350. That is, the louvers 360 are arranged along the airflow. The louvers 360 are provided by cutting out a portion of the upright fin surface 350. Furthermore, by cutting out a portion of the upright fin surface 350, slits 360a for air passage are formed at positions corresponding to each louver 360. Thus, the louvers 360 serve to guide the air passing through the slits 360a.

[0145] Drain slits 370 are formed near the center of each fin surface 350 in the first direction to drain water from the fin surface 350. Drain slits 370 have a rectangular shape extending in the second direction. As described later, the center position of each drain slit 370 in the second direction is offset from each other at least between adjacent fin surfaces 350 in the height direction, and the end positions also differ from each other in the second direction.

[0146] When the heat exchanger 30 functions as an evaporator, the surface temperatures of the flat tubes 38 and the corrugated fins 39a are lower than the temperature of the air passing through the heat exchanger 30. Therefore, moisture in the air condenses on the surfaces of the flat tubes 38 and the corrugated fins 39a, generating condensed water 380.

[0147] Condensed water 380 generated on the surfaces of each fin surface 350 of the corrugated fins 39a flows toward the drainage slits 370 and flows down toward the fin surface 350 below. In areas where the amount of condensed water 380 is high, the condensed water 380 easily flows along the fin surface 350, and thus easily flows through the drainage slits 370 toward the fin surface 350 below. On the other hand, in areas where the amount of condensed water 380 is low, the condensed water 380 easily remains on the fin surface 350 and stagnates, making it difficult for it to flow along the fin surface 350.

[0148] Figure 14 It is a front view schematically showing a heat exchanger 30 according to the seventh embodiment. Figure 15 (a) to (e) are correct Figure 14 FIG. 3 is a diagram illustrating the positional relationship of the drainage slits 370 in each fin surface 350 of the corrugated fin 39a shown in FIG. Figure 15 (a) to (e) represent Figure 14 The heat sink surface 350 at positions (a) to (e).

[0149] As mentioned above, Figure 14 and Figure 15 As shown in (a) to (e) of FIG. 1 , each drainage slit 370 is formed so that its center position in the second direction is offset from one another on at least two fin surfaces 350 adjacent in the height direction, and its end positions are also different from one another in the second direction. Furthermore, although not particularly limited, in the heat exchanger 30 according to Embodiment 7, drainage slits 370 having the same center position in the second direction are periodically present on each fin surface 350 of a single corrugated fin 39a.

[0150] Therefore, the condensed water 380 flowing down from the end of the drain slit 370 in the second direction falls onto the next fin surface 350. The condensed water 380 that has fallen onto the next fin surface 350 then merges with the condensed water 380 that has remained on the surface of that fin surface 350. The condensed water 380, which has increased in volume due to the merger, easily passes through the drain slit 370 and flows down toward the fin surface 350 below. Consequently, the amount of condensed water 380 that remains on the surface of the fin surface 350 is reduced, enabling efficient drainage and suppressing a decrease in defrosting performance.

[0151] Figure 16 This is a diagram illustrating the flow of condensed water 380 on the surface of the corrugated fin 39a of the heat exchanger 30 according to the seventh embodiment.

[0152] The top portion 390 of the corrugated fins 39a, which is the portion joined to the flat tubes 38, is formed by bending the corrugated fins 39a, and the spacing between the fin surfaces 350 becomes narrower at the top portion 390. Therefore, the condensed water 380 at the top portion 390 is easily retained and accumulated there due to surface tension.

[0153] In the heat exchanger 30 according to the seventh embodiment, for example, Figure 15 (d) Figure 15 (e) and Figure 16 As shown, the end of the drainage slit 370 in the second direction can be arranged at the top 390 or near the top 390. If the end of the drainage slit 370 in the second direction is at the top 390 or near the top 390, the condensed water 380 at the top 390 can be merged with the condensed water 380 flowing down from the heat sink surface 350 above it. The condensed water 380 at the top 390 breaks the surface tension by merging with the condensed water 380 flowing down from the heat sink surface 350 above it, and flows out from the top 390 and flows down to the heat sink surface 350 below it. In addition, as Figure 15 As shown in (a) to (c) of FIG. 5 , by arranging the drainage slits 370 at both ends of the fin surface 350 in the second direction, drainage can be more efficiently achieved.

[0154] As described above, in the heat exchanger 30 involved in embodiment 7, drainage slits 370 for drainage are formed on each heat sink surface 350, and the positions of the ends of the drainage slits 370 formed on the heat sink surfaces 350 adjacent to each other in the height direction are different from each other in the arrangement direction of the flat tubes 38.

[0155] In the heat exchanger 30 according to Embodiment 7, condensed water 380 flowing from the ends of the drain slits 370 in the direction in which the flat tubes 38 are arranged falls onto the next fin surface 350. The condensed water 380 that has fallen onto the next fin surface 350 then merges with the condensed water 380 that has remained on the surface of that fin surface 350. The increased amount of condensed water 380 due to the merger makes it easier for the condensed water 380 to pass through the drain slits 370 and flow down toward the next fin surface 350. Consequently, the amount of condensed water 380 that remains on the surface of the fin surface 350 is reduced, enabling efficient drainage and suppressing a decrease in defrosting performance.

[0156] Description of Reference Numerals

[0157] 10...Outdoor unit; 11...Compressor; 12...Flow path switching device; 13...Fan; 20...Indoor unit; 21...Throttling device; 22...Indoor heat exchanger; 23...Indoor fan; 30...Heat exchanger; 30a...First heat exchange section; 30b...Second heat exchange section; 31...Heat exchanger; 31a...First heat exchanger; 31b...Second heat exchanger; 31b1...First region; 31b2...Second region; 31b3...Third region; 33...Extension piping; 34...Lower header; 34a...First lower header; 34b...Second lower header; 34b1...First flow path; 34b2...Second flow path; 35...Upper header; 35a...First upper header; 35b...Second Upper header; 35b1...first area; 35b2...second area; 36...liquid piping; 37...gas piping; 38...flat tube; 39...heat sink; 39a...corrugated fin; 40...partition plate; 41...second partition plate; 42...first flow path; 43...second flow path; 44...opening; 50...bending area; 60...connecting pipe; 100...air conditioning unit; 311...first area; 312...second area; 313...third area; 314...fourth area; 341...first portion; 342...second portion; 350...heat sink surface; 360...louver; 360a...slit; 370...drainage slit; 380...condensed water; 390...top.

Claims

1. A heat exchanger, characterized in that: have: A heat exchanger having a plurality of flat tubes arranged at intervals in a horizontal direction; an upper header, disposed at the upper end of the heat exchanger; a lower header, disposed at the lower end of the heat exchanger; an extension pipe through which refrigerant flows out when the evaporator functions, and through which refrigerant flows in when the condenser functions; and a partition plate disposed inside at least one of the upper header and the lower header, and dividing the heat exchanger into a plurality of areas in the horizontal direction; The upper header and the lower header have a bent region where a bending process is performed. The partition plate is arranged so that each of the regions forms a countercurrent with the adjacent regions, and is arranged so that the flow path cross-sectional area of each region decreases from the upstream side toward the downstream side of the refrigerant flow when functioning as a condenser. The partition plate is arranged in an area other than the bending area. The extension pipe is provided below the lower header in parallel with the lower header along the longitudinal direction of the lower header, and at least a portion of the extension pipe is in contact with the lower header.

2. The heat exchanger according to claim 1, characterized in that When the device functions as a condenser, the refrigerant flowing in the most downstream region is an upward flow, and the refrigerant flow in this region has an overflow constant C>1.

3. The heat exchanger according to claim 1, characterized in that When functioning as a condenser, the refrigerant flowing in the region on the most downstream side is a downflow.

4. The heat exchanger according to any one of claims 1 to 3, characterized in that The heat exchanger includes a first heat exchanger and a second heat exchanger. The upper header comprises: a first upper header provided at the upper end of the first heat exchanger; and a second upper header provided at the upper end of the second heat exchanger. The lower header comprises: a first lower header provided at the lower end of the first heat exchanger; and a second lower header provided at the lower end of the second heat exchanger. The first upper header and the second upper header, or the first lower header and the second lower header are connected to communicate with each other via a connecting pipe.

5. The heat exchanger according to claim 4, characterized in that The first heat exchanging element and the second heat exchanging element have different lengths, When functioning as a condenser, the refrigerant flowing through the connecting pipe is a downward flow or a horizontal flow.

6. The heat exchanger according to any one of claims 1 to 3 and 5, characterized in that: A plurality of corrugated fins are arranged between adjacent flat tubes. Each corrugated fin has a wave shape and comprises: a plurality of tops engaged with the flat tubes; and A plurality of heat sink surfaces are arranged between the top portions and configured along the height direction.

7. The heat exchanger according to claim 6, characterized in that Drainage slits are formed on each fin surface for drainage. Positions of ends of the drainage slits formed on the fin surfaces adjacent to each other in the height direction are different from each other in the arrangement direction of the flat tubes.

8. An outdoor unit, characterized in that: A heat exchanger according to any one of claims 1 to 7 is provided.

9. An air conditioning device, characterized in that: A device comprising the outdoor unit according to claim 8.

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