Heat exchanger and air conditioner

Abstract

This heat exchanger is equipped with: a plurality of flat tubes through which a refrigerant flows; and a plurality of fins disposed between the flat tubes and conducting the heat of the refrigerant flowing through the flat tubes. The fins each have: a planar portion having openings formed in some thereof; and a louver defining the openings of the planar portion. Slits for discharging water that has gathered on the planar portion are formed in those areas of the planar portion where the planar portion is in contact with end portions of the flat tubes.

Description

Heat exchanger and air conditioning device

[0001] The present disclosure relates to a heat exchanger including flat tubes and fins, and an air conditioning apparatus.

[0002] Conventionally, heat exchangers including flat tubes and fins have been known. Patent Document 1 discloses a heat exchanger including a plurality of flat tubes and a corrugated fin with a plurality of louvers. Patent Document 1 discloses a corrugated fin heat exchanger in which a slit is formed in the center of the corrugated fin. The slit is formed at a position furthest from each of the upstream and downstream ends of the flat tube in the air flow direction. Patent Document 1 thus aims to prevent freezing by using the slit to release the freezing load even if the surface temperature drops below the freezing point and there is a possibility of freezing.

[0003] JP 2015-183908 A

[0004] However, when the heat exchanger functions as an evaporator when the outside air temperature is low, the accumulation of condensation on the fins can reduce the heating capacity. Although Patent Document 1 has slits, it does not take drainage into consideration. There is a need for a heat exchanger that can efficiently drain water that accumulates on the fins.

[0005] The present disclosure has been made to solve the above-mentioned problems, and provides a heat exchanger and an air conditioner that efficiently discharge water.

[0006] The heat exchanger of the present disclosure comprises a plurality of flat tubes through which a refrigerant flows, and a plurality of fins arranged between the flat tubes to transfer heat from the refrigerant flowing through the flat tubes, the fins having a planar portion with an opening formed in part thereof and louvers that form the opening in the planar portion, and a slit formed in the part of the planar portion that comes into contact with the end of the flat tube to drain water that accumulates in the planar portion.

[0007] According to the present disclosure, slits are formed in the flat portions of the fins at the portions where they come into contact with the ends of the flat tubes to drain water that accumulates on the flat portions. When condensation occurs on the fins, the water is drained through the slits. The water that passes through the slits is guided to the ends of the flat tubes, where it falls downward without accumulating on the fins, etc. Therefore, water can be efficiently drained.

[0008] FIG. 1 is a circuit diagram showing an air conditioning apparatus according to embodiment 1. FIG. 2 is a front view showing a heat exchanger according to embodiment 1. FIG. 3 is a top view showing a heat exchanger according to embodiment 1. FIG. 4 is a side view showing a heat exchanger according to embodiment 1. FIG. 5 is a top view showing a heat exchanger according to embodiment 1. FIG. 6 is a top view showing a heat exchanger according to embodiment 2. FIG. 7 is a top view showing a heat exchanger according to embodiment 3. FIG. 8 is a top view showing a heat exchanger according to embodiment 4. FIG. 9 is a top view showing a heat exchanger according to embodiment 5. FIG. 10 is a top view showing a heat exchanger according to embodiment 6. FIG. 11 is a top view showing a heat exchanger according to embodiment 7.

[0009] Hereinafter, embodiments of a heat exchanger and an air conditioning apparatus according to the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. Furthermore, in the following drawings, including FIG. 1, the dimensional relationships between components may differ from the actual relationships. Furthermore, in the following description, terms indicating directions are used as appropriate to facilitate understanding of the present disclosure. However, these terms are for the purpose of explaining the present disclosure and do not limit the present disclosure. Examples of terms indicating directions include "up," "down," "right," "left," "front," and "rear." Note that hatching in cross-sectional views has been partially omitted in some of the drawings.

[0010] Embodiment 1. Figure 1 is a circuit diagram showing an air conditioner 1 according to embodiment 1. As shown in Figure 1, the air conditioner 1 is a device that conditions the air in an indoor space, and includes an outdoor unit 2 and an indoor unit 3 connected to the outdoor unit 2. The outdoor unit 2 is provided with a compressor 6, a flow path switching device 7, a heat exchanger 8, an outdoor blower 9, and an expansion section 10. The indoor unit 3 is provided with an indoor heat exchanger 11 and an indoor blower 12.

[0011] A compressor 6, a flow switching device 7, a heat exchanger 8, an expansion section 10, and an indoor heat exchanger 11 are connected by refrigerant piping 5 to form a refrigerant circuit 4 through which a refrigerant (working gas) flows. The compressor 6 draws in refrigerant in a low-temperature, low-pressure state, compresses the drawn refrigerant, and discharges it as a high-temperature, high-pressure refrigerant. The flow switching device 7, which is, for example, a four-way valve, switches the direction of refrigerant flow in the refrigerant circuit 4. The heat exchanger 8 exchanges heat between, for example, outdoor air and the refrigerant. The heat exchanger 8 functions as a condenser during cooling operation and as an evaporator during heating operation.

[0012] The outdoor fan 9 is a device that sends outdoor air to the heat exchanger 8. The expansion section 10 is a pressure reducing valve or expansion valve that reduces the pressure of the refrigerant to expand it. The expansion section 10 is, for example, an electronic expansion valve whose opening degree is adjustable. The indoor heat exchanger 11 is, for example, a device that exchanges heat between the indoor air and the refrigerant. The indoor heat exchanger 11 acts as an evaporator during cooling operation and as a condenser during heating operation. The indoor fan 12 is a device that sends indoor air to the indoor heat exchanger 11.

[0013] (Operation Modes, Cooling Operation) Next, the operation modes of the air conditioner 1 will be described. First, cooling operation will be described. In cooling operation, the refrigerant drawn into the compressor 6 is compressed by the compressor 6 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 6 passes through the flow switching device 7 and flows into the heat exchanger 8, which functions as a condenser. In the heat exchanger 8, the refrigerant exchanges heat with outdoor air sent by the outdoor fan 9, condensing and liquefying. The condensed liquid refrigerant flows into the expansion section 10, where it expands and is decompressed to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant then flows into the indoor heat exchanger 11, which functions as an evaporator. In the indoor heat exchanger 11, the refrigerant exchanges heat with indoor air sent by the indoor fan 12, evaporating and gasifying. At this time, the indoor air is cooled, and cooling is performed in the room. The evaporated refrigerant in a low-temperature, low-pressure gas state passes through the flow switching device 7 and is sucked into the compressor 6 .

[0014] (Operation Mode, Heating Operation) Next, the heating operation will be described. In the heating operation, the refrigerant drawn into the compressor 6 is compressed by the compressor 6 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 6 passes through the flow switching device 7 and flows into the indoor heat exchanger 11, which functions as a condenser. In the indoor heat exchanger 11, the refrigerant exchanges heat with indoor air sent by the indoor blower 12, condensing and liquefying. At this time, the indoor air is heated, and heating is performed in the room. The condensed liquid refrigerant flows into the expansion section 10, where it expands and decompresses to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant then flows into the heat exchanger 8, which functions as an evaporator. In the heat exchanger 8, the refrigerant exchanges heat with outdoor air sent by the outdoor blower 9, evaporating and gasifying. The evaporated low-temperature, low-pressure gas refrigerant passes through the flow switching device 7 and is drawn into the compressor 6.

[0015] The air conditioner 1 does not have to have the flow path switching device 7. In this case, the air conditioner 1 becomes a dedicated cooling machine or a dedicated heating machine.

[0016] Fig. 2 is a front view showing the heat exchanger 8 according to the first embodiment. Next, the heat exchanger 8 will be described in detail. As shown in Fig. 2, the heat exchanger 8 is, for example, a parallel flow type heat exchanger 8. Note that the heat exchanger 8 may also be a fin tube type heat exchanger 8. The heat exchanger 8 includes flat tubes 20, fins 30, and a header 40.

[0017] (Flat Tubes 20) The flat tubes 20 are tubes through which a refrigerant flows. A plurality of flat tubes 20 are arranged side by side and are made of, for example, aluminum or an aluminum alloy. The plurality of flat tubes 20 are arranged at intervals so that their longitudinal axes face each other, and fins 30 are provided between the flat tubes 20. The flat tubes 20 may also be made of a clad material with an aluminum core. The flat tubes 20 have, for example, a plurality of flow paths formed in a row through which the refrigerant flows. The flat tubes 20 extend with their height direction as the longitudinal direction.

[0018] (Fins 30) The fins 30 are components that transfer heat from the refrigerant flowing through the flat tubes 20, and are, for example, corrugated fins that are bent and arranged between the flat tubes 20. The width of the fins 30 is equal to the distance between adjacent flat tubes 20. The fins 30 have inclined surfaces that are inclined with respect to the horizontal direction and are alternately folded back. In other words, the fins 30 can be described as strip-shaped members that are alternately folded back and arranged in multiple rows in the height direction. Between the fins 30 and the flat tubes 20, ventilation channels 31 are formed through which air flows. The fins 30 are made of, for example, aluminum. The fins 30 may also be plate fins.

[0019] (Header 40) The header 40 allows the refrigerant to flow therethrough and distributes the refrigerant to the connected flat tubes 20. The header 40 is made of, for example, aluminum. As described above, the header 40 may be made of the same material as the fins 30 and the flat tubes 20, or a different material may be used. The header 40 includes a header 40 that connects one end of the flat tubes 20 and a header 40 that connects the other end of the flat tubes 20. The interior of the header 40 may be configured such that the space through which the refrigerant flows is partitioned by one or more partitions. A refrigerant pipe 5 is connected to one of the headers 40, and the header 40 is connected to the flow path switching device 7 via the refrigerant pipe 5. A refrigerant pipe 5 is connected to the other header 40, and the header 40 is connected to the expansion section 10 via the refrigerant pipe 5. The header 40 may be made of the same material as the flat tubes 20.

[0020] (Flat surface portion 32) Fig. 3 is a top view showing the heat exchanger 8 according to the first embodiment. As shown in Fig. 3, the fin 30 has a flat surface portion 32 and a plurality of louvers 33. The flat surface portion 32 is a plate-shaped member extending at an angle along the longitudinal axis direction of the flat tubes 20. The flat surface portion 32 has a rectangular opening 32a (see Fig. 4) extending along the longitudinal axis direction of the flat tubes 20 formed in a part of the center of the flat surface portion 32, excluding both end portions adjacent to the flat tubes 20.

[0021] (Louvers 33) Fig. 4 is a side view showing the heat exchanger 8 according to the first embodiment. As shown in Fig. 4, the louvers 33 form openings 32a in the planar portion 32. A plurality of louvers 33 are provided for each opening 32a. The louvers 33 are formed by cutting and raising a portion of the planar portion 32, and are inclined in a side view. In a side view, one end of the louvers 33 is higher than the planar portion 32 and the other end is lower than the planar portion 32.

[0022] (Slits 35) As shown in FIG. 3 , slits 35 for discharging water 50 accumulated in the flat portion 32 are formed in the portions of the flat portion 32 that contact the ends of the flat tubes 20. Here, the ends of the flat tubes 20 refer to the ends of the flat tubes 20 in the longitudinal direction. In this manner, the slits 35 are formed in the flat portion 32 so as to be continuous with the ends of the flat tubes 20. The slits 35 are also formed in the flat portion 32 of the fins 30 that face the vicinity of the center of the flat tubes 20 in the longitudinal direction. The slits 35 extend in the direction in which the flat tubes 20 face each other. That is, the slits 35 extend along the minor axis direction of the flat tubes 20. In the first embodiment, the slits 35 are rectangular, but are not limited to a rectangular shape.

[0023] As shown in Fig. 3, the slits 35 are formed on the upwind side, which is the upstream side in the air flow, of the flat portion 32 of the fin 30. The opening area of ​​the multiple slits 35 is larger on the upwind side of the fin 30 than on the downwind side. In the first embodiment, the slits 35 are formed only on the upwind side, but the slits 35 may also be formed on the downwind side. Furthermore, the slits 35 are formed only on the upwind end side of the flat tube 20, but they may also be formed on the downwind end side of the flat tube 20.

[0024] As shown in Fig. 4, a plurality of louvers 33 are provided, and the louvers 33 located on both ends of the slit 35 are inclined in line symmetry with respect to the slit 35. The louvers 33 located on one end of the slit 35 are inclined while gradually descending toward the slit 35, and the louvers 33 located on the other end of the slit 35 are also inclined while gradually descending toward the slit 35. In other words, the inclination directions of the louvers 33 located on both ends of the slit 35 are different from each other.

[0025] FIG. 5 is a top view showing the heat exchanger 8 according to the first embodiment. Next, the positions of the slits 35 in the bent fins 30 adjacent in the height direction will be described. In FIG. 5, the fin 30 on the left side is the upper fin 30, the fin 30 in the middle fin 30, and the fin 30 on the right side is the lower fin 30. Also, in FIG. 5, the upper side is the upwind side and the lower side is the downwind side. As shown in FIG. 5, the slits 35 are offset from one another in the height direction. Although FIG. 5 illustrates an example in which the lengths of the slits 35 in the minor axis direction of the flat tubes 20 are the same, they may be different.

[0026] Furthermore, the offset of the slits 35 may be periodic or non-periodic. If the slits 35 are periodic, the manufacturing process is simplified. Furthermore, the bonding strength between the flat tubes 20 and the fins 30 is higher when no slits 35 are formed in any of the flat tubes 20, as in the fins 30 in the center and on the right side of FIG. 5 . By periodically offsetting the positions of the slits 35 in the height direction, as in the first embodiment, it is possible to achieve both high drainage performance and high bonding strength.

[0027] According to the first embodiment, slits 35 for draining water accumulated in the flat portions 32 are formed in the portions of the flat portions 32 of the fins 30 that contact the ends of the flat tubes 20. When condensation occurs on the fins 30, the water is drained through the slits 35. The water that passes through the slits 35 is guided to the ends of the flat tubes 20, and falls downward without remaining on the fins 30, etc. Therefore, the water can be drained efficiently. This improves the heating capacity.

[0028] The slits 35 extend in the direction in which the flat tubes 20 face each other. This increases the bonding area between the flat tubes 20 and the fins 30. This increases the bonding area between the flat tubes 20 and the fins 30 while ensuring drainage. The slits 35 of the fins 30, which are aligned vertically, are offset from one another in the vertical direction. This allows droplets adhering to the fins 30 to fall through the upper slits 35, strike the lower flat surface 32, flow along the inclined flat surface 32, and then fall through the slits 35. This means that droplets are less likely to accumulate on the fins 30. This achieves a balance between bonding strength and low-temperature heating capacity.

[0029] The slits 35 are formed on the upwind side of the fins 30. The opening area of ​​the multiple slits 35 is larger on the upwind side of the fins 30 than on the downwind side. This allows for improved drainage on the upwind side, where the amount of frost and dehumidification is greater. This, in turn, improves the heating low-temperature capacity. Furthermore, the louvers 33 located on both ends of the slits 35 are inclined downward in line symmetry with respect to the slits 35. This allows water generated on the louvers 33 to be guided to the slits 35 through the inclined surfaces of the louvers 33 and then discharged through the slits 35. This allows for improved drainage.

[0030] Embodiment 2. Figure 6 is a top view showing a heat exchanger 8 according to embodiment 2. Embodiment 2 differs from embodiment 1 in that multiple rows of flat tubes 20 are provided. In embodiment 2, parts common to embodiment 1 are given the same reference numerals and description thereof will be omitted, and the description will focus on the differences from embodiment 1.

[0031] As shown in Fig. 6, the flat tubes 20 are arranged in multiple rows in the longitudinal direction of the fins 30. In the second embodiment, two rows of the flat tubes 20 are illustrated, but three or more rows may be provided. Here, the spaces between the multiple rows of flat tubes 20 are referred to as inter-row portions 32b. The slits 35 are portions of the planar portion 32 that come into contact with the ends of the flat tubes 20, and are formed in the inter-row portions 32b.

[0032] The inter-row portions 32b have a large portion that is not in contact with the flat tubes 20 compared to the other planar portions 32, and therefore do not have a high heat exchange capacity. According to the second embodiment, the slits 35 are formed in the inter-row portions 32b between the multiple rows of flat tubes 20, and therefore, drainage can be improved without reducing the heat exchange capacity.

[0033] Embodiment 3. Figure 7 is a top view showing a heat exchanger 8 according to embodiment 3. This embodiment 3 differs from embodiment 2 in the position where the slits 35 are formed. In this embodiment 3, parts that are common to embodiments 1 and 2 are given the same reference numerals and description thereof will be omitted, and the description will focus on the differences from embodiments 1 and 2.

[0034] 7 , the slits 35 are formed in all of the portions of the inter-row portions 32b that come into contact with the ends of the flat tubes 20. As described above, the inter-row portions 32b have many portions that do not come into contact with the flat tubes 20 compared to the other planar portions 32, and therefore do not have high heat exchange capacity. According to the third embodiment, the slits 35 are formed in all of the portions of the inter-row portions 32b that come into contact with the ends of the flat tubes 20, and therefore, it is possible to further improve drainage without reducing heat exchange capacity.

[0035] 8 is a top view showing a heat exchanger 8 according to a fourth embodiment. This fourth embodiment differs from the first embodiment in that the slits 35 are formed on the upwind side and the downwind side of the fins 30. In this fourth embodiment, the same parts as those in the first to third embodiments are denoted by the same reference numerals and their description will be omitted, and the following description will focus on the differences from the first to third embodiments.

[0036] As shown in Figure 8, the slits 35 are formed on the windward and leeward sides of the fins 30. This allows water to be discharged using all of the ends of the flat tubes 20. Water that passes through the slits 35 is guided to the ends of the flat tubes 20, and falls downward without accumulating on the fins 30 or the like. This allows water to be discharged efficiently. Furthermore, because the water is guided along the ends of the flat tubes 20, rapid drainage is achieved. This further improves heating capacity.

[0037] 9 is a top view showing a heat exchanger 8 according to a fifth embodiment. The fifth embodiment differs from the fourth embodiment in that the slits 35 are formed only in the portions of the planar portion 32 that come into contact with the ends of the flat tubes 20. In the fifth embodiment, the same parts as those in the first to fourth embodiments are denoted by the same reference numerals and their description is omitted, and the following description will focus on the differences from the first to fourth embodiments.

[0038] As shown in Figure 9, the slits 35 are formed only in the portions of the flat portion 32 that contact the ends of the flat tubes 20. In other words, the slits 35 are not formed in the flat portion 32 of the fins 30 that are joined to the flat tubes 20. This makes it possible to improve drainage without reducing heat exchange capacity as much as possible. Furthermore, because water is guided along the ends of the flat tubes 20, rapid drainage is achieved.

[0039] Sixth Embodiment Fig. 10 is a top view showing a heat exchanger 8 according to a sixth embodiment. In this sixth embodiment, the opening area of ​​the slits 35 differs between the inter-row portion 32b and the portion other than the inter-row portion 32b. In this sixth embodiment, the same parts as those in the first to fifth embodiments are denoted by the same reference numerals and their description is omitted, and the following description will focus on the differences from the first to fifth embodiments.

[0040] 10 , the opening area of ​​the slits 35 is larger in the inter-row portions 32b than in other portions. This improves drainage without reducing heat exchange capacity as much as possible. Furthermore, because water is guided along the ends of the flat tubes 20, rapid drainage is achieved.

[0041] Seventh Embodiment Fig. 11 is a top view showing a heat exchanger 8 according to a seventh embodiment. This seventh embodiment differs from the first to sixth embodiments in the opening area of ​​the slits 35. In this seventh embodiment, the same parts as those in the first to sixth embodiments are denoted by the same reference numerals and their description is omitted, and the following description will focus on the differences from the first to sixth embodiments.

[0042] As shown in Figure 11, the flat surface 32 is formed with slits 35 that have a larger opening area on the upwind side of the fin 30 than on the downwind side. This improves drainage on the upwind side, where the amount of frost and dehumidification is greater, thereby improving the heating low-temperature capacity.

[0043] REFERENCE SIGNS LIST 1 Air conditioning device, 2 Outdoor unit, 3 Indoor unit, 4 Refrigerant circuit, 5 Refrigerant piping, 6 Compressor, 7 Flow path switching device, 8 Heat exchanger, 9 Outdoor blower, 10 Expansion section, 11 Indoor heat exchanger, 12 Indoor blower, 20 Flat tube, 30 Fin, 31 Ventilation channel, 32 Flat section, 32a Opening, 32b Inter-row section, 33 Louver, 35 Slit, 40 Header, 50 Water.

Claims

1. A heat exchanger comprising: a plurality of flat tubes through which a refrigerant flows; and a plurality of fins provided between the flat tubes for transferring heat of the refrigerant flowing through the flat tubes, wherein the fins have a flat portion with an opening formed in a part of the flat portion, and louvers that form the opening in the flat portion, and a slit is formed in the part of the flat portion that comes into contact with the end of the flat tube to drain water that accumulates in the flat portion.

2. A heat exchanger according to claim 1, wherein the slits extend in a direction in which the flat tubes face each other.

3. A heat exchanger according to claim 1 or 2, wherein the flat tubes extend with their longitudinal direction in the height direction, the fins are arranged in multiple rows in the height direction, and the slits of the fins arranged in the height direction are offset from one another in the height direction.

4. A heat exchanger according to any one of claims 1 to 3, wherein the slits are formed on the upwind side of the fins.

5. A heat exchanger according to any one of claims 1 to 4, wherein the opening area of ​​the plurality of slits is larger on the upwind side of the fin than on the downwind side.

6. A heat exchanger according to any one of claims 1 to 5, wherein the flat tubes are arranged in multiple rows in the longitudinal direction of the fins, and the slits are formed in the inter-row portions between the multiple rows of the flat tubes.

7. A heat exchanger according to claim 6, wherein the slits are formed in all of the portions of the inter-row sections that come into contact with the ends of the flat tubes.

8. A heat exchanger according to claim 6 or 7, wherein the opening area of ​​the slits is larger in the inter-row portions than in portions other than the inter-row portions.

9. A heat exchanger according to any one of claims 1 to 8, wherein the slits are formed on the upwind side and the downwind side of the fin.

10. A heat exchanger according to any one of claims 1 to 9, wherein the slits are formed only in the portions of the planar portion that come into contact with the ends of the flat tubes.

11. A heat exchanger according to any one of claims 1 to 10, wherein a plurality of louvers are provided, and the louvers arranged on both ends of the slit are inclined downwardly and linearly symmetrically with respect to the slit.

12. A heat exchanger comprising: a plurality of flat tubes through which a refrigerant flows; and a plurality of fins provided between the flat tubes for transferring heat of the refrigerant flowing through the flat tubes, wherein the fins have a planar portion with an opening formed in a portion thereof, and louvers that form the opening in the planar portion, and the planar portion has slits formed therein, the opening area of ​​which is larger on the upwind side of the fins than on the downwind side.

13. An air conditioner comprising a heat exchanger according to any one of claims 1 to 12.

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