Heat exchanger and air conditioner

Abstract

The present invention comprises: a plurality of flat heat transfer pipes extending in the vertical direction and arranged in parallel with each other; and a corrugated fin disposed between two mutually adjacent flat heat transfer pipes among the plurality of flat heat transfer pipes. The corrugated fin has a first top portion joined to one of the two flat heat transfer pipes, a second top portion joined to the other of the two flat heat transfer pipes, and a flat portion formed between the first and second top portions. A louver is formed in the flat portion, the louver having a louver slit and a plate part inclined with respect to the flat portion. A drainage slit is formed in the flat portion to drain condensation water. At least one edge portion around the drainage slit has an inclined portion that is inclined with respect to the flat portion. In the direction perpendicular to the flat portion, the projection height of the inclined portion from the flat portion is lower than the projection height of the plate part from the flat portion.

Description

Heat exchanger and air conditioning device

[0001] The present disclosure relates to a heat exchanger and an air conditioner including the same.

[0002] Patent Document 1 discloses a corrugated fin for an evaporator. The flat surface of the corrugated fin is formed with multiple louvers and drainage holes for draining condensed water. The drainage holes are formed by bending downward notched pieces of the corrugated fin.

[0003] Japanese Utility Model Application Publication No. 56-78966

[0004] However, the corrugated fins have a problem in that the notched pieces protrude into the air flow path, which can increase ventilation resistance.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a heat exchanger and an air conditioning apparatus that can improve drainage performance while suppressing an increase in ventilation resistance.

[0006] The heat exchanger according to the present disclosure comprises a plurality of flat heat transfer tubes extending in the vertical direction and arranged in parallel to one another, and a corrugated fin arranged between two adjacent flat heat transfer tubes among the plurality of flat heat transfer tubes, wherein the corrugated fin has a first apex joined to one of the two flat heat transfer tubes, a second apex joined to the other of the two flat heat transfer tubes, and a flat portion formed between the first apex and the second apex, and the flat portion has louvers formed in the flat portion, and the louvers have louver slits and a plate portion inclined with respect to the flat portion, and the flat portion has drainage slits for draining condensation water, and at least one edge portion around the drainage slit has an inclined portion inclined with respect to the flat portion, and in a direction perpendicular to the flat portion, the protruding height of the inclined portion from the flat portion is lower than the protruding height of the plate portion from the flat portion.

[0007] An air conditioning apparatus according to the present disclosure includes a heat exchanger according to the present disclosure.

[0008] According to the present disclosure, it is possible to improve the drainage performance of a heat exchanger while suppressing an increase in ventilation resistance.

[0009] 12. A diagram showing a schematic configuration of a heat exchanger according to embodiment 1. A perspective view showing a schematic configuration of a heat exchanger according to embodiment 1. A diagram schematically showing a cross section of a corrugated fin in a heat exchanger according to embodiment 1. A cross-sectional view showing the configuration of a drainage slit in a heat exchanger according to embodiment 1. A cross-sectional view showing the configuration of a drainage slit in a heat exchanger according to embodiment 1. A diagram showing the configuration of an air conditioning apparatus according to embodiment 1. A graph showing the relationship between the protrusion height of a plate portion from a flat portion in a direction perpendicular to the flat portion of a heat exchanger according to embodiment 1 and ventilation resistance. A diagram showing an example of the protrusion direction of an inclined portion in a heat exchanger according to embodiment 1. A diagram showing another example of the protrusion direction of an inclined portion in a heat exchanger according to embodiment 1. A top view showing the configuration of a flat portion in a heat exchanger according to embodiment 2. A top view showing the configuration of a flat portion in a heat exchanger according to embodiment 2. A top view showing the configuration of a flat portion in a heat exchanger according to embodiment 2. A top view showing the configuration of a flat portion in a heat exchanger according to embodiment 2. A diagram schematically showing a cross section taken along line XIII-XIII in FIG. 12. A diagram schematically showing a cross section of a corrugated fin in a heat exchanger according to embodiment 3.

[0010] Embodiments of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to the following embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure. Furthermore, the present disclosure includes all possible combinations of the configurations shown in the following embodiments. In particular, the combinations of components are not limited to the combinations in each embodiment; components described in one embodiment can be applied to another embodiment. In the following description, directional terms (e.g., "up," "down," "right," "left," "front," "rear," etc.) are used as appropriate to facilitate understanding, but these are for explanatory purposes and do not limit the present disclosure. In each drawing, components designated with the same reference numerals are identical or equivalent, and this applies throughout the entire specification. Note that the relative dimensional relationships or shapes of each component in each drawing may differ from those in reality.

[0011] Embodiment 1. A heat exchanger and an air conditioning apparatus according to embodiment 1 will be described. Fig. 1 is a diagram showing the schematic configuration of a heat exchanger according to this embodiment. As shown in Fig. 1, a heat exchanger 10 according to this embodiment is a parallel piping type corrugated fin tube heat exchanger. The heat exchanger 10 has a plurality of flat heat transfer tubes 1, a plurality of corrugated fins 2, and a pair of headers 3A, 3B.

[0012] Here, to clarify the correspondence between the drawings including FIG. 1 , the following coordinate system is defined. The Z axis is taken along the extension direction of the flat heat transfer tubes 1, with the upward direction being the +Z direction. In this embodiment, the Z axis is parallel to the vertical direction. The X axis is taken along the air flow direction, with the downstream side of the air flow being the +X direction. The Y axis is taken along the parallel direction of the flat heat transfer tubes 1, with one of the directions along the Y axis being the +Y direction. In this embodiment, the XY plane including the X axis and Y axis is a horizontal plane perpendicular to the Z axis.

[0013] Because the heat exchanger 10 of this embodiment is of a vertical flow type, the headers 3A and 3B are arranged vertically spaced apart from each other. Each of the headers 3A and 3B is connected via piping to other devices that constitute the refrigerant circuit of the air conditioning system, and is configured to split or merge the refrigerant. Liquid refrigerant mainly flows through the header 3A arranged at the bottom. Gas refrigerant mainly flows through the header 3B arranged at the top.

[0014] The flat heat transfer tubes 1 extend in the vertical direction. One end of each of the flat heat transfer tubes 1 is connected to one header 3A. The other end of each of the flat heat transfer tubes 1 is connected to the other header 3B. The flat heat transfer tubes 1 are arranged in parallel with one another at intervals. Each of the flat heat transfer tubes 1 extends perpendicular to the extension direction of the headers 3A and 3B.

[0015] The flat heat transfer tube 1 has a flat cross-sectional shape. The longitudinal direction of the cross section of the flat heat transfer tube 1 is aligned with the air flow direction. The outer surfaces of the longitudinal sides of the cross section of the flat heat transfer tube 1 are flat, and the outer surfaces of the lateral sides are curved. The flat heat transfer tube 1 is a multi-hole flat heat transfer tube having a plurality of holes that serve as refrigerant flow paths. The flat heat transfer tubes 1 are arranged at equal intervals in the horizontal direction, with their outer surfaces facing each other on their longitudinal sides. When manufacturing the heat exchanger 10 of embodiment 1, each flat heat transfer tube 1 is inserted into an insertion hole (not shown) of each header 3A, 3B and joined by brazing.

[0016] When the heat exchanger 10 is used as a condenser, a high-temperature, high-pressure refrigerant flows through the refrigerant flow paths within the flat heat transfer tubes 1. When the heat exchanger 10 is used as an evaporator, a low-temperature, low-pressure refrigerant flows through the refrigerant flow paths within the flat heat transfer tubes 1. The refrigerant flows into one of the headers 3A and 3B via a pipe (not shown) that supplies the refrigerant from an external device (not shown) to the heat exchanger 10. The refrigerant that flows into one header is distributed and passes through each of the flat heat transfer tubes 1. The flat heat transfer tubes 1 exchange heat between the refrigerant passing through the tubes and the air passing outside the tubes. When the refrigerant temperature is higher than the air temperature, the refrigerant releases its heat to the air. When the refrigerant temperature is lower than the air temperature, the refrigerant absorbs heat from the air. The refrigerant that has exchanged heat after passing through the flat heat transfer tubes 1 flows into the other of the headers 3A and 3B and merges. The refrigerant then flows back to the external device (not shown) through a pipe (not shown) connected to the other header.

[0017] The corrugated fins 2 are disposed between two adjacent flat heat transfer tubes 1. The corrugated fins 2 are provided to increase the heat transfer area between the refrigerant and the air. The corrugated fins 2 are formed by corrugating a plate material and folding it in a zigzag pattern, which is made up of repeated mountain and valley folds. The folded portions of the corrugated fins 2 form the peaks of the corrugated fins 2.

[0018] FIG. 2 is a perspective view showing a schematic configuration of a heat exchanger according to this embodiment. As shown in FIG. 2, the corrugated fin 2 has a first apex 2a on one side and a second apex 2b, a flat portion 2c, and a flat portion 2d on the other side. The first apex 2a is in surface contact with one of the flat heat transfer tubes 1. The second apex 2b is in surface contact with the other flat heat transfer tube 1. The contact portions between the corrugated fin 2 and the flat heat transfer tube 1 are joined by brazing. The corrugated fin 2 is formed, for example, using a clad material in which brazing filler metal layers are formed on both sides of an aluminum alloy plate. The brazing filler metal layers are formed, for example, from an aluminum-silicon-based brazing filler metal containing aluminum. The plate thickness of the corrugated fin 2 is approximately 50 μm to 200 μm.

[0019] The flat portions 2c and 2d are each formed between the first apex 2a and the second apex 2b. The flat portions 2c and 2d are both formed in a flat plate shape. The flat portions 2c and 2d are alternately arranged along the extension direction of the flat heat transfer tube 1. The flat portions 2c are inclined with respect to the horizontal plane so that the height on the first apex 2a side is higher than the height on the second apex 2b side. The flat portions 2d are inclined with respect to the horizontal plane so that the height on the second apex 2b side is higher than the height on the first apex 2a side. The flat portions 2c and 2d have the same configuration except for the direction of inclination. The following description will mainly use the flat portion 2c as an example.

[0020] FIG. 3 is a schematic diagram illustrating a cross section of a corrugated fin in a heat exchanger according to this embodiment. FIG. 3 shows a cross section of the flat portion 2c of the corrugated fin 2 cut along a plane parallel to the X-axis and perpendicular to the flat portion 2c. The up-down direction in FIG. 3 does not correspond to the Z-axis, but rather to the direction perpendicular to the flat portion 2c. The left side of FIG. 3 represents the upstream side in the air flow. Note that FIG. 3 primarily illustrates the positional relationship between the louvers 22 and the drainage slits 23 and the inclination direction of the plate portions 22b of the louvers 22. Therefore, the configuration of the flat portion 2c shown in FIG. 3 does not necessarily match the configuration of the flat portion 2c shown in FIG. 2.

[0021] As shown in Fig. 3, a plurality of louver groups 21 are formed on the flat portion 2c. The plurality of louver groups 21 are arranged in parallel along the air flow direction. Each of the louver groups 21 is made up of a plurality of louvers 22. The plurality of louvers 22 are arranged in parallel along the air flow direction.

[0022] Each louver 22 has louver slits 22a that allow air to pass through and plate portions 22b that guide the air to the louver slits 22a. The plate portions 22b are inclined obliquely with respect to the flat portion 2c. The plate portions 22b of multiple louvers 22 included in the same louver group 21 are inclined in the same direction. In the example shown in FIG. 3, the plate portions 22b of multiple louvers 22 included in different louver groups 21 are also inclined in the same direction. The plate portions 22b of each louver 22 shown in FIG. 3 are inclined so that their height decreases from the upwind side to the downwind side. Each louver 22 is formed by cutting the plate portions 22b from the flat portion 2c. In this embodiment, each plate portion 22b is composed of an upper plate portion cut upward from the flat portion 2c and a lower plate portion cut downward from the flat portion 2c.

[0023] In the flat portion 2c, drainage slits 23 are formed between two adjacent louver groups 21 to allow condensed water to pass through and drain downward. The drainage slits 23 are formed in a rectangular shape in a plan view. The short sides of the drainage slits 23 are aligned along the air flow direction. The long sides of the drainage slits 23 are aligned along the parallel arrangement direction of the flat heat transfer tubes 1.

[0024] Figures 4 and 5 are cross-sectional views showing the configuration of drainage slits in a heat exchanger according to this embodiment. Figure 4 shows a cross-section of the flat portion 2c of the corrugated fin 2 taken perpendicular to the X-axis, i.e., a cross-section of the flat portion 2c taken along the long side of the drainage slit 23. Figure 5 shows a cross-section of the flat portion 2c of the corrugated fin 2 taken along a plane parallel to the X-axis and perpendicular to the flat portion 2c, i.e., a cross-section of the flat portion 2c taken along the short side of the drainage slit 23. The up-down direction in Figures 4 and 5 does not represent the Z-axis, but represents the direction perpendicular to the flat portion 2c.

[0025] 4 and 5, the flat portion 2c has edge portions 2c1, 2c2, 2c3, and 2c4 located around the drainage slit 23. The edge portions 2c1 and 2c2 are along the short sides of the drainage slit 23. The edge portions 2c1 and 2c2 are opposed to each other with the drainage slit 23 in between. The edge portions 2c3 and 2c4 are along the long sides of the drainage slit 23. The edge portions 2c3 and 2c4 are opposed to each other with the drainage slit 23 in between.

[0026] An inclined portion is provided on at least one edge portion around the drainage slit 23. In this embodiment, inclined portions 24a, 24b, 24c, and 24d are formed on all edge portions 2c1, 2c2, 2c3, and 2c4 of the drainage slit 23, respectively. The inclined portions may be provided only on the edge portions 2c1 and 2c2 along the short sides of the drainage slit 23. When the inclined portions are provided only on the edge portions 2c1 and 2c2 along the short sides of the drainage slit 23, each inclined portion is aligned with the air flow direction, thereby suppressing an increase in ventilation resistance.

[0027] The inclined portions 24a, 24b, 24c, and 24d are all formed in a plate shape. The inclined portions 24a, 24b, 24c, and 24d may be connected in an elliptical shape so as to surround the entire circumference of the drainage slit 23. The inclined portions 24a, 24b, 24c, and 24d are all inclined with respect to the flat portion 2c. In this embodiment, the inclination angles of the inclined portions 24a, 24b, 24c, and 24d with respect to the flat portion 2c are greater than the inclination angle of the flat portion 2c with respect to the horizontal plane, so the inclined portions 24a, 24b, 24c, and 24d are also inclined with respect to the horizontal plane. The inclination angles of the inclined portions 24a, 24b, 24c, and 24d with respect to the flat portion 2c may be different from one another. Alternatively, the inclination angles may be 90°.

[0028] The inclined portion 24a protrudes downward from the edge portion 2c1 toward the drainage slit 23. A bent portion 25a is formed between the inclined portion 24a and the edge portion 2c1. The bent portion 25a is curved so as to be convex toward the drainage slit 23. The inclination angle of the inclined portion 24a with respect to the flat portion 2c is θ1.

[0029] The inclined portion 24b protrudes downward from the edge portion 2c2 toward the drainage slit 23. A bent portion 25b is formed between the inclined portion 24b and the edge portion 2c2. The bent portion 25b is curved so as to be convex toward the drainage slit 23.

[0030] The inclined portion 24c protrudes downward from the edge portion 2c3 toward the drainage slit 23. A bent portion 25c is formed between the inclined portion 24c and the edge portion 2c3. The bent portion 25c is curved so as to be convex toward the drainage slit 23. The inclination angle of the inclined portion 24c with respect to the flat portion 2c is θ2. The inclination angle θ2 is smaller than the inclination angle θ1 (θ2<θ1).

[0031] The inclined portion 24d protrudes downward from the edge portion 2c4 toward the drainage slit 23. A bent portion 25d is formed between the inclined portion 24d and the edge portion 2c4. The bent portion 25d is curved so as to be convex toward the drainage slit 23.

[0032] In a direction perpendicular to the flat portion 2c, i.e., the vertical direction in FIG. 3, the protruding height of each of the inclined portions 24a, 24b, 24c, and 24d from the flat portion 2c is defined as h. The protruding height h is the distance between the tip of each inclined portion and the thickness-wise center of the flat portion 2c. Because each inclined portion protrudes from the flat portion 2c, the protruding height h is greater than 0. In a direction perpendicular to the flat portion 2c, i.e., the vertical direction in FIG. 3, the protruding height H of the plate portion 22b from the flat portion 2c is defined as the distance between the tip of the plate portion 22b and the thickness-wise center of the flat portion 2c, for example, in the same direction as the protruding direction of the inclined portion. The multiple plate portions 22b may be formed with a constant protruding height or may be formed with irregularly varying protruding heights. If the protruding heights of the multiple plate portions 22b formed on one flat portion 2c are not constant, the average protruding height of each plate portion 22b is defined as H. At this time, the protrusion height h is smaller than the protrusion height H (h<H).

[0033] 6 is a diagram showing the configuration of an air conditioning apparatus according to this embodiment. In this embodiment, the heat exchanger 10 described above is used as the indoor heat exchanger 110. However, the heat exchanger 10 described above may also be used as the outdoor heat exchanger 230, or may be used as both the indoor heat exchanger 110 and the outdoor heat exchanger 230.

[0034] As shown in Fig. 6, the air conditioning apparatus has an outdoor unit 200 and an indoor unit 100. The outdoor unit 200 and the indoor unit 100 are connected by a gas refrigerant pipe 300 and a liquid refrigerant pipe 400. The outdoor unit 200 has a compressor 210, a four-way valve 220, an outdoor heat exchanger 230, and an outdoor fan 240. The indoor unit 100 has an indoor heat exchanger 110, a pressure reducer 120, and an indoor fan 130.

[0035] The compressor 210 compresses the drawn refrigerant and discharges it. Although not particularly limited, the compressor 210 can change its capacity by arbitrarily changing its operating frequency using, for example, an inverter circuit. The four-way valve 220 is a valve that switches the flow of refrigerant depending on, for example, whether the unit is in cooling operation or heating operation.

[0036] The outdoor heat exchanger 230 exchanges heat between the refrigerant and outdoor air. During heating operation, the outdoor heat exchanger 230 functions as an evaporator, evaporating and vaporizing the refrigerant. During cooling operation, the outdoor heat exchanger 230 functions as a condenser, condensing and liquefying the refrigerant. The outdoor fan 240 supplies outdoor air to the outdoor heat exchanger 230 to promote heat exchange in the outdoor heat exchanger 230.

[0037] The indoor heat exchanger 110 exchanges heat between the refrigerant and the indoor air, which is the space to be air-conditioned. During heating operation, the indoor heat exchanger 110 functions as a condenser, condensing and liquefying the refrigerant. During cooling operation, the indoor heat exchanger 110 functions as an evaporator, evaporating and vaporizing the refrigerant. The indoor fan 130 supplies indoor air to the indoor heat exchanger 110 and supplies the air that has passed through the indoor heat exchanger 110 into the room.

[0038] The pressure reducer 120 reduces the pressure of the refrigerant to expand it. An electronic expansion valve, a temperature-sensitive expansion valve, a throttling device, or the like is used as the pressure reducer 120. When an electronic expansion valve is used as the pressure reducer 120, the pressure reducer 120 adjusts its opening degree based on instructions from a control device (not shown) or the like.

[0039] Next, the operation of each device in the air conditioner will be described based on the flow of refrigerant. First, the operation of each device in the refrigerant circuit during heating operation will be described based on the flow of refrigerant. High-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the indoor heat exchanger 110. The gas refrigerant passing through the indoor heat exchanger 110 condenses and liquefies by exchanging heat with indoor air. The liquefied refrigerant passes through the pressure reducer 120 and is reduced in pressure, becoming a two-phase gas-liquid state. The two-phase gas-liquid refrigerant passes through the outdoor heat exchanger 230. The refrigerant passing through the outdoor heat exchanger 230 evaporates and gasifies by exchanging heat with outdoor air supplied by the outdoor fan 240. The gasified refrigerant passes through the four-way valve 220 and is drawn back into the compressor 210. The heating operation of the air conditioner is performed by circulating the refrigerant in this manner.

[0040] Next, cooling operation will be described. The high-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 210 passes through the four-way valve 220 and flows into the outdoor heat exchanger 230. The gas refrigerant passing through the outdoor heat exchanger 230 condenses and liquefies by exchanging heat with outdoor air supplied by the outdoor fan 240. The liquefied refrigerant passes through the pressure reducer 120 to be reduced in pressure and enters a two-phase gas-liquid state. The two-phase gas-liquid refrigerant passes through the indoor heat exchanger 110. The refrigerant passing through the indoor heat exchanger 110 evaporates and gasifies by exchanging heat with indoor air supplied by the indoor fan 130. The gasified refrigerant passes through the four-way valve 220 and is drawn back into the compressor 210. The air conditioning system operates in a cooling mode by circulating the refrigerant in this manner.

[0041] When the heat exchanger 10 functions as an evaporator, the surface temperatures of the flat heat transfer tubes 1 and the corrugated fins 2 become lower than the temperature of the air passing through the heat exchanger 10. Therefore, moisture in the air condenses on the surfaces of the flat heat transfer tubes 1 and the corrugated fins 2. As a result, condensed water is generated on the surfaces of the flat heat transfer tubes 1 and the corrugated fins 2.

[0042] Condensation water generated on the surface of the corrugated fin 2 may accumulate on the flat portion 2c around the drainage slit 23. However, in this embodiment, downwardly protruding inclined portions 24a, 24b, 24c, and 24d are provided on the edge portion around the drainage slit 23. Therefore, the condensation water adhering to the flat portion 2c around the drainage slit 23 flows down along the inclined portions 24a, 24b, 24c, and 24d, making it easier to drain from the drainage slit 23.

[0043] Therefore, according to this embodiment, it is possible to improve the drainage of condensation water when the heat exchanger 10 functions as an evaporator. Furthermore, in this embodiment, the protrusion height h of the inclined portions 24a, 24b, 24c, and 24d from the flat portion 2c is smaller than the protrusion height H of the plate portion 22b from the flat portion 2c. This makes it possible to make the protrusion of the inclined portions 24a, 24b, 24c, and 24d from the flat portion 2c smaller than the protrusion of the plate portion 22b, thereby suppressing an increase in ventilation resistance due to the provision of the inclined portions 24a, 24b, 24c, and 24d.

[0044] 7 is a graph showing the relationship between the protrusion height of the plate portions from the flat portions of the heat exchanger according to this embodiment in a direction perpendicular to the flat portions and the ventilation resistance. The vertical axis of the graph represents the ventilation resistance ΔP of air passing through the corrugated fin 2 in the +X direction. The horizontal axis of the graph represents the protrusion height h of the inclined portions 24a, 24b, 24c, and 24d from the flat portions 2c in a direction perpendicular to the flat portions 2c, in relation to the protrusion height H.

[0045] 7, when the protrusion height h is equal to or greater than H / 2 but less than H, the ventilation resistance ΔP is generally constant regardless of the protrusion height h. On the other hand, when the protrusion height h is less than H / 2, the ventilation resistance ΔP decreases as the protrusion height h decreases. Therefore, in order to more effectively suppress the increase in ventilation resistance caused by providing the inclined portions 24a, 24b, 24c, and 24d, it is desirable that the protrusion height h be less than half the protrusion height H (h<H / 2).

[0046] Fig. 8 is a diagram showing an example of the protruding direction of the inclined portions in the heat exchanger according to the present embodiment. As shown in Fig. 8, the flat portions 2c and 2d are adjacent to each other with a gap in between in the direction along the extension direction of the flat heat transfer tube 1. The flat portions 2c and 2d are inclined in opposite directions relative to the horizontal plane.

[0047] The inclined portions 24a and 24b formed on the flat portion 2c protrude upward from the flat portion 2c. Although not shown, the inclined portions 24c and 24d formed on the flat portion 2c also protrude upward from the flat portion 2c. On the other hand, the inclined portions 24a and 24b formed on the flat portion 2d protrude downward from the flat portion 2d. Although not shown, the inclined portions 24c and 24d formed on the flat portion 2d also protrude downward from the flat portion 2d. As such, in the example shown in Figure 8, the protruding directions of the inclined portions 24a, 24b, 24c, and 24d in the vertical direction are different between adjacent flat portions 2c and 2d.

[0048] When the inclined portions 24a, 24b, 24c, and 24d protrude downward like the flat portion 2d, the condensed water adhering to the flat portion 2d flows down along the inclined portions 24a, 24b, 24c, and 24d, and is therefore more easily drained through the drainage slits 23.

[0049] Even when the inclined portions 24a, 24b, 24c, and 24d protrude upward, as in the case of the flat portion 2c, the condensed water adhering to the flat portion 2c tends to move vertically along the inclined portions 24a, 24b, 24c, and 24d due to surface tension. This prevents the condensed water from accumulating on the flat portion 2c, and promotes drainage through the drainage slits 23 or along the flat heat transfer tube 1. Therefore, each of the inclined portions 24a, 24b, 24c, and 24d has the function of promoting drainage of condensed water, regardless of the direction of protrusion in the vertical direction.

[0050] 9 is a diagram showing another example of the protruding direction of the inclined portions in the heat exchanger according to the present embodiment. As shown in FIG. 9, the inclined portion 24a formed on the flat portion 2c protrudes downward from the flat portion 2c. The inclined portion 24b formed on the flat portion 2c protrudes upward from the flat portion 2c. Although not shown, the inclined portions 24c and 24d formed on the flat portion 2c protrude upward or downward from the flat portion 2c.

[0051] The inclined portion 24a formed on the flat portion 2d protrudes upward from the flat portion 2d. The inclined portion 24b formed on the flat portion 2d protrudes downward from the flat portion 2d. Although not shown, the inclined portions 24c and 24d formed on the flat portion 2d protrude upward or downward from the flat portion 2d. The configuration shown in Figure 9 also provides the same effect as the configuration shown in Figure 8.

[0052] As described above, the heat exchanger 10 according to this embodiment includes a plurality of flat heat transfer tubes 1 and corrugated fins 2. Each of the plurality of flat heat transfer tubes 1 extends in the vertical direction. The plurality of flat heat transfer tubes 1 are arranged in parallel with one another. The corrugated fin 2 is arranged between two adjacent flat heat transfer tubes 1 among the plurality of flat heat transfer tubes 1. The corrugated fin 2 has a first apex 2a joined to one of the two flat heat transfer tubes 1, a second apex 2b joined to the other of the two flat heat transfer tubes 1, and a flat portion 2c formed between the first apex 2a and the second apex 2b.

[0053] Louvers 22 are formed on the flat portion 2c. The louvers 22 have louver slits 22a and plate portions 22b inclined with respect to the flat portion 2c. Drainage slits 23 for draining condensation water are formed on the flat portion 2c. Sloped portions 24a, 24b, 24c, and 24d inclined with respect to the flat portion 2c are provided on at least one edge portion 2c1, 2c2, 2c3, and 2c4 around the drainage slit 23. In a direction perpendicular to the flat portion 2c, the protruding height h of the sloped portions 24a, 24b, 24c, and 24d from the flat portion 2c is smaller than the protruding height H of the plate portion 22b from the flat portion 2c.

[0054] According to this configuration, as described above, the provision of the inclined portions 24a, 24b, 24c, and 24d can improve the drainage performance of the heat exchanger 10. Furthermore, since the protrusion of the inclined portions 24a, 24b, 24c, and 24d from the flat portion 2c can be made smaller than the protrusion of the plate portion 22b, an increase in ventilation resistance due to the provision of the inclined portions 24a, 24b, 24c, and 24d can be suppressed.

[0055] In the heat exchanger 10 according to this embodiment, in the direction perpendicular to the flat portion 2c, the protruding height h of the inclined portions 24a, 24b, 24c, and 24d from the flat portion 2c is less than half the protruding height H of the plate portion 22b from the flat portion 2c.

[0056] According to this configuration, it is possible to more effectively suppress an increase in ventilation resistance caused by providing the inclined portions 24a, 24b, 24c, and 24d.

[0057] In the heat exchanger 10 according to the present embodiment, the inclined portions 24a, 24b, 24c, and 24d are provided on at least two edge portions that face each other around the drainage slit 23. The inclined portions provided on the two edge portions protrude in the same vertical direction.

[0058] According to this configuration, the inclined portions can be easily formed on the corrugated fins 2 .

[0059] In the heat exchanger 10 according to the present embodiment, the flat portion includes two flat portions 2c and 2d that are adjacent to each other in the up-down direction. The inclined portions provided on the two flat portions 2c and 2d protrude in opposite directions in the up-down direction.

[0060] According to this configuration, the inclined portions provided on the two flat portions 2 c, 2 d both protrude from one surface of the plate material constituting the corrugated fin 2. Therefore, the inclined portions can be easily formed on the corrugated fin 2.

[0061] In the heat exchanger 10 according to this embodiment, the inclined portions 24 a , 24 b , 24 c , and 24 d are provided around the entire circumference of the drainage slit 23 .

[0062] According to this configuration, accumulation of condensed water can be suppressed all around the drainage slit 23, thereby further improving the drainage performance of the heat exchanger 10.

[0063] In the heat exchanger 10 according to this embodiment, the drain slits 23 have long sides that are aligned along the parallel arrangement direction of the flat heat transfer tubes 1 and short sides that are aligned along the air flow direction. The inclination angle θ1 of the inclined portions 24a provided along the short sides relative to the flat portions 2c is larger than the inclination angle θ2 of the inclined portions 24c provided along the long sides relative to the flat portions 2c.

[0064] According to this configuration, the inclination angle θ1 of the inclined portion 24a can be made larger on the short side where the effect of surface tension is greater than on the long side, thereby further improving the drainage performance of the heat exchanger 10.

[0065] The air conditioner according to this embodiment has the heat exchanger 10 according to this embodiment. With this configuration, the same effects as those described above can be obtained in the air conditioner.

[0066] Embodiment 2. A heat exchanger according to embodiment 2 will be described. Figures 10 to 12 are top views showing the configuration of flat portions in a heat exchanger according to this embodiment. Figure 10 shows the configuration of a certain flat portion 2c. Figure 11 shows, for example, the configuration of a flat portion 2d arranged below and adjacent to the flat portion 2c shown in Figure 10. Figure 12 shows, for example, the configuration of a flat portion 2c arranged below and adjacent to the flat portion 2d shown in Figure 11. Figure 13 is a schematic view of the XIII-XIII cross section of Figure 12.

[0067] 10 to 13, the drainage slits 23 of two vertically adjacent flat portions are formed at different positions in the parallel arrangement direction of the flat heat transfer tubes 1. That is, the drainage slit 23 of the lower of the two flat portions is not located directly below the drainage slit 23 of the upper flat portion. This allows condensation water flowing down from the upper drainage slit 23 to merge with condensation water remaining in the flat portion around the lower drainage slit 23. This prevents condensation water from remaining, improving the drainage performance of the heat exchanger 10.

[0068] In this embodiment, the positions of the drainage slits 23 in the parallel arrangement direction of the flat heat transfer tubes 1 are periodically shifted along the extension direction of the flat heat transfer tubes 1. The drainage slits 23 shown in Fig. 10 are formed only in the flat portion 2c. The drainage slits 23 shown in Fig. 11 are formed across the flat portion 2d and the first apex portion 2a. The drainage slits 23 shown in Figs. 12 and 13 are formed across the flat portion 2c, the second apex portion 2b, and the flat portion 2d. The drainage slits 23 shown in Figs. 10, 11, and 12 appear periodically along the extension direction of the flat heat transfer tube 1.

[0069] Generally, the gap between the flat portion 2c and the flat portion 2d is narrow in the inner portions of the first and second apexes 2a and 2b, and condensation water tends to accumulate therein due to surface tension. However, in this embodiment, the drainage slits 23 formed across the first and second apexes 2a and 2b periodically appear, making it easier for condensation water accumulated in the inner portions of the first and second apexes 2a and 2b to be drained.

[0070] Other configurations are the same as those of embodiment 1. According to this embodiment, the drainage performance can be further improved compared to embodiment 1.

[0071] As described above, in the heat exchanger 10 according to this embodiment, the flat portion includes two flat portions 2c, 2d that are adjacent to each other in the vertical direction. The drainage slits 23 of the two flat portions 2c, 2d are formed at different positions in the parallel arrangement direction of the flat heat transfer tubes 1. The flat portion also includes a plurality of flat portions 2c, 2d that are arranged in parallel in the vertical direction. The positions of the drainage slits 23 of the flat portions 2c, 2d are periodically shifted in the parallel arrangement direction of the flat heat transfer tubes 1.

[0072] With this configuration, condensation water flowing down from the upper drainage slits 23 can be merged with condensation water remaining in the flat areas around the lower drainage slits 23. Furthermore, because the drainage slits 23 formed across the first apex 2a or the second apex 2b appear periodically, condensation water remaining in the inner areas of the first apex 2a and the second apex 2b can be easily drained. This makes it possible to prevent condensation water from remaining, improving the drainage performance of the heat exchanger 10.

[0073] Embodiment 3 A heat exchanger according to embodiment 3 will be described. Fig. 14 is a diagram schematically showing a cross section of a corrugated fin in a heat exchanger according to this embodiment. Fig. 14 shows a cross section corresponding to Fig. 3.

[0074] 14, the drainage slit 23 is disposed between the louver group 21-1 and the louver group 21-2. The louver group 21-1 is disposed on the windward side of the drainage slit 23. The louver group 21-2 is disposed on the leeward side of the drainage slit 23. Hereinafter, each louver 22 included in the louver group 21-1 may be referred to as a first louver, and each louver 22 included in the louver group 21-2 may be referred to as a second louver.

[0075] Plate portion 22b of the first louver is inclined relative to flat portion 2c so that its height decreases as it approaches drainage slit 23. Plate portion 22b of the second louver is similarly inclined relative to flat portion 2c so that its height decreases as it approaches drainage slit 23. In other words, plate portion 22b of the first louver and plate portion 22b of the second louver are inclined in opposite directions to each other.

[0076] The other configurations are the same as those of the first embodiment. This embodiment also provides the same effects as those of the first embodiment.

[0077] As described above, in the heat exchanger 10 according to this embodiment, the louvers include first and second louvers. The first louvers are arranged on the upwind side of the drainage slits 23. The second louvers are arranged on the downwind side of the drainage slits 23. The plate portions 22b of the first louvers and the plate portions 22b of the second louvers are both inclined with respect to the flat portion 2c so that their heights decrease as they approach the drainage slits 23.

[0078] 1 Flat heat transfer tube, 2 Corrugated fin, 2a First top, 2b Second top, 2c Flat portion, 2c1, 2c2, 2c3, 2c4 Edge portion, 2d Flat portion, 3A, 3B Header, 10 Heat exchanger, 21, 21-1, 21-2 Louver group, 22 Louver, 22a Louver slit, 22b Plate portion, 23 Drainage slit, 24a, 24b, 24c, 24d Inclined portion, 25a, 25b, 25c, 25d Bent portion, 100 Indoor unit, 110 Indoor heat exchanger, 120 Pressure reducer, 130 Indoor fan, 200 Outdoor unit, 210 Compressor, 220 Four-way valve, 230 Outdoor heat exchanger, 240 Outdoor fan, 300 Gas refrigerant piping, 400 Liquid refrigerant piping.

Claims

1. A heat exchanger includes a plurality of flat heat transfer tubes extending in the vertical direction and arranged in parallel with each other, and corrugated fins arranged between two adjacent flat heat transfer tubes among the plurality of flat heat transfer tubes. The corrugated fin has a first top portion joined to one of the two flat heat transfer tubes, a second top portion joined to the other of the two flat heat transfer tubes, and a flat portion formed between the first top portion and the second top portion. A louver is formed in the flat portion. The louver has a louver slit and a plate portion inclined with respect to the flat portion. A drain slit for draining condensed water is formed in the flat portion. At least one edge portion around the drain slit is provided with an inclined portion inclined with respect to the flat portion. In a direction perpendicular to the flat portion, the protruding height of the inclined portion from the flat portion is lower than the protruding height of the plate portion from the flat portion.

2. The heat exchanger according to claim 1, wherein in a direction perpendicular to the flat portion, the protruding height of the inclined portion from the flat portion is lower than half of the protruding height of the plate portion from the flat portion.

3. The heat exchanger according to claim 1 or 2, wherein the inclined portion is provided at least at two edge portions facing each other around the drain slit, and the inclined portions provided at the two edge portions protrude in the same direction in the vertical direction.

4. The heat exchanger according to any one of claims 1 to 3, wherein the flat portion includes two flat portions adjacent to each other in the vertical direction, and the inclined portions provided at the two flat portions protrude in opposite directions in the vertical direction.

5. The heat exchanger according to any one of claims 1 to 4, wherein the inclined portion is provided on the entire circumference around the drain slit.

6. The heat exchanger according to any one of claims 1 to 5, wherein the drain slit has a long side along the parallel direction of the plurality of flat heat transfer tubes and a short side along the air flow direction, and the inclination angle of the inclined portion provided along the short side with respect to the flat portion is larger than the inclination angle of the inclined portion provided along the long side with respect to the flat portion.

7. The flat portion includes two flat portions adjacent to each other in the vertical direction, and the drainage slits of each of the two flat portions are formed at different positions in the parallel direction of the plurality of flat heat transfer tubes. The heat exchanger according to any one of claims 1 to 6.

8. The flat portion includes a plurality of flat portions arranged in parallel in the vertical direction, and the positions of the drainage slits of each of the plurality of flat portions are periodically shifted in the parallel direction of the plurality of flat heat transfer tubes. The heat exchanger according to any one of claims 1 to 6.

9. The louver includes a first louver disposed upstream of the drainage slit in the wind direction and a second louver disposed downstream of the drainage slit in the wind direction. The plate portions of both the first louver and the second louver are inclined with respect to the flat portion such that the height decreases as they approach the drainage slit. The heat exchanger according to any one of claims 1 to 8.

10. An air conditioner having the heat exchanger according to any one of claims 1 to 9.

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