Air conditioner

Abstract

An air conditioner (1) is provided with an outdoor unit (2) including a first heat exchanger (200), and an indoor unit (3) including a second heat exchanger (300). The first heat exchanger (200) has a first heat transfer tube (210) and a plurality of first fins (220). The second heat exchanger (300) has a second heat transfer tube (310) and a plurality of second fins (320). The first heat transfer tube (210), the first fin (220), the second heat transfer tube (310), and the second fin (320) are made of aluminum or an aluminum alloy. A first sacrificial layer (212) is provided on the surface of the first heat transfer tube (210). The potential of the first sacrificial layer (212) is lower than the potential of the base material of the first heat transfer tube (210) and higher than the potential of the first fin (220). The zinc content of the first fins (220) is higher than the zinc content of the second fins (320).

Description

Technical Field

[0001] The present disclosure relates to an air conditioner. Background Art

[0002] In the past, as disclosed in Patent Document 1 (International Publication No. 2017 / 141943), a heat exchanger having a heat transfer tube for refrigerant flow and fins fixed to the heat transfer tube is known. The heat exchanger of Patent Document 1 has an aluminum tube as a heat transfer tube and an aluminum fin as a fin, and the natural potential of the surface of the aluminum tube is higher than the natural potential of the surface of the aluminum fin, and the potential difference between the two is 30mV to 200mV. Summary of the invention

[0003] Problems to be solved by the invention

[0004] However, the inventors of the present invention have discovered that the heat exchanger of Patent Document 1 described above may not be used for an indoor unit.

[0005] Means for solving problems

[0006] The air conditioner of the first aspect comprises an outdoor unit and an indoor unit. The outdoor unit comprises a first heat exchanger. The first heat exchanger comprises a first heat transfer tube and a plurality of first fins. The first heat transfer tube is made of aluminum or an aluminum alloy. The plurality of first fins are made of aluminum or an aluminum alloy. The indoor unit comprises a second heat exchanger. The second heat exchanger comprises a second heat transfer tube and a plurality of second fins. The second heat transfer tube is made of aluminum or an aluminum alloy. The plurality of second fins are made of aluminum or an aluminum alloy. A first sacrificial layer is provided on the surface of the first heat transfer tube. The potential of the first sacrificial layer is lower than the potential of the base material of the first heat transfer tube and higher than the potential of the first fin. The first fin contains zinc. The zinc content of the first fin is higher than the zinc content of the second fin.

[0007] According to the air conditioner of the first aspect, a first sacrificial layer having a lower potential than that of a base material is provided on the first heat transfer tube made of aluminum or aluminum alloy, thereby suppressing corrosion of the base material. In addition, since the potential of the first sacrificial layer is higher than that of the first fin, corrosion of the first sacrificial layer for suppressing corrosion of the base material can be suppressed.

[0008] However, if zinc is contained in order to lower the potential of the fin, the fin will solidify, and thus the workability will be deteriorated. Therefore, in the air conditioner of the first viewpoint, the first fin of the outdoor unit is not required to have workability compared with the second fin of the indoor unit, and the zinc content of the first fin is made higher than the zinc content of the second fin. Thus, the workability of the second fin of the indoor unit can be ensured, and therefore, the second heat exchanger having the second fin can be used for the indoor unit.

[0009] The air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the zinc content of the first fin is 2% by mass or more.

[0010] In the air conditioner according to the second aspect, by setting the zinc content of the first fin of the outdoor unit to 2 mass % or more, it is possible to realize the first sacrificial layer having a potential that is sufficient to suppress corrosion of the base material.

[0011] The air conditioner according to a third aspect is the air conditioner according to the first aspect or the second aspect, wherein a fin pitch of the second fins is larger than a fin pitch of the first fins.

[0012] Since the zinc content of the second fin is lower than that of the first fin, the second fin is prone to corrosion. Therefore, in the air conditioner of the third aspect, by making the fin pitch of the second fin larger than the fin pitch of the first fin, the surface area of ​​the second fin in contact with the second heat transfer tube can be reduced. Therefore, the corrosion of the second fin can be suppressed.

[0013] An air conditioner according to a fourth aspect is the air conditioner according to the third aspect, wherein a difference between a fin pitch of the first fin and a fin pitch of the second fin is 0.1 mm or more and 0.3 mm or less.

[0014] In the air conditioner according to the fourth aspect, by setting the pitch difference to 0.1 mm or more and 0.3 mm or less, corrosion of the second fins can be further suppressed.

[0015] An air conditioner according to a fifth aspect is the air conditioner according to any one of the first to fourth aspects, wherein the potential of the first fin is lower than the potential of the second fin.

[0016] The first heat exchanger of the outdoor unit is more susceptible to salt damage than the second heat exchanger of the indoor unit. Therefore, in the air conditioner of the fifth aspect, by making the potential of the first fin lower than that of the second fin, the first fin becomes a sacrifice for the first heat transfer tube, thereby further suppressing the corrosion of the first heat transfer tube.

[0017] The air conditioner according to a sixth aspect is the air conditioner according to the first to fifth aspects, wherein a second sacrificial layer is provided on the surface of the second heat transfer tube, and the second sacrificial layer has a potential lower than that of a base material of the second heat transfer tube and lower than that of the second fin.

[0018] The second heat exchanger of the indoor unit is less susceptible to salt damage than the first heat exchanger of the outdoor unit. Therefore, in the air conditioner of the sixth aspect, even if the potential of the second sacrificial layer of the indoor unit is lower than the potential of the second fin, corrosion of the base material can be suppressed. In addition, the reduction in the processability of the second fin can be further suppressed.

[0019] According to a seventh aspect, in the air conditioner according to any one of the first to sixth aspects, the first heat transfer tube has a flat shape, and the second heat transfer tube has a cylindrical shape.

[0020] The fins attached to the cylindrical heat transfer tubes require better workability than the fins attached to the flat heat transfer tubes. Therefore, in the air conditioner of the seventh aspect, the second heat transfer tube of the indoor unit requires better workability than the first heat transfer tube of the outdoor unit. Therefore, the air conditioner of the present disclosure is appropriately used.

[0021] The air conditioner of the eighth aspect comprises an outdoor unit and an indoor unit. The outdoor unit comprises a first heat exchanger. The first heat exchanger comprises a first heat transfer tube and a plurality of first fins. The first heat transfer tube is made of aluminum or an aluminum alloy. The plurality of first fins are made of aluminum or an aluminum alloy. The indoor unit comprises a second heat exchanger. The second heat exchanger comprises a second heat transfer tube and a plurality of second fins. The second heat transfer tube is made of aluminum or an aluminum alloy. The plurality of second fins are made of aluminum or an aluminum alloy. A first sacrificial layer is provided on the surface of the first heat transfer tube. The potential of the first sacrificial layer is lower than the potential of the base material of the first heat transfer tube and higher than the potential of the first fin. The elongation of the second fin is greater than the elongation of the first fin.

[0022] According to the air conditioner of the eighth aspect, a first sacrificial layer having a lower potential than that of a base material is provided on the first heat transfer tube made of aluminum or aluminum alloy, thereby suppressing corrosion of the base material. In addition, since the potential of the first sacrificial layer is higher than that of the first fin, corrosion of the first sacrificial layer for suppressing corrosion of the base material can be suppressed.

[0023] However, if the potential of the fin is lowered, the fin will solidify, and thus the workability will be deteriorated. Therefore, in the air conditioner of the eighth aspect, the first fin of the outdoor unit is not required to have workability compared to the second fin of the indoor unit, and the elongation of the second fin is made greater than the elongation of the first fin. Thus, the workability of the second fin of the indoor unit can be ensured, and therefore, the second heat exchanger having the second fin can be used for the indoor unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an external view of an air conditioner according to one embodiment of the present disclosure.

[0025] Figure 2 This is a schematic diagram of the outdoor unit.

[0026] Figure 3 This is a schematic diagram of the indoor unit.

[0027] Figure 4 is a perspective view of the first heat exchanger.

[0028] Figure 5 is a cross-sectional view of the first heat transfer tube.

[0029] Figure 6 is a perspective view of the second heat exchanger.

[0030] Figure 7 is a cross-sectional view of the second heat transfer tube.

[0031] Figure 8 is a cross-sectional view of the second fin.

[0032] Fig. 9 is a plan view of the second fin. DETAILED DESCRIPTION

[0033] An air conditioner according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. In the following description, expressions such as "up" and "down" are used as appropriate to indicate directions, but these indicate directions in a normal use state and are not limiting.

[0034] (1) Overall structure

[0035] like Figure 1 As shown, an air conditioner 1 according to an embodiment of the present disclosure includes an outdoor unit 2, an indoor unit 3, and a communication pipe 4. The outdoor unit 2 is installed outdoors. The indoor unit 3 is installed indoors. Here, the indoor unit 3 is installed on a wall surface indoors. The communication pipe 4 connects the outdoor unit 2 and the indoor unit 3. Such an air conditioner 1 can perform indoor cooling operation, heating operation, etc.

[0036] like Figure 2 As shown, the outdoor unit 2 includes a first heat exchanger 200, a first fan 21, a first drain pan 22, etc. The first fan 21 draws outdoor air into the outdoor unit 2, supplies the outdoor air to the first heat exchanger 200, and then discharges the outdoor air to the outside of the outdoor unit 2. The first heat exchanger 200 performs heat exchange between the outdoor air and the refrigerant. The first heat exchanger 200 is a heat exchanger that functions as a radiator of the refrigerant during cooling operation and as an evaporator of the refrigerant during heating operation. The first drain pan 22 receives water.

[0037] like Figure 3 As shown, the indoor unit 3 includes a second heat exchanger 300, a second fan 31, a second drain pan 32, etc. The first fan 33 draws indoor air into the indoor unit 3, supplies the indoor air to the second heat exchanger 300, and then discharges the indoor air to the outside of the indoor unit 3. The second heat exchanger 300 performs heat exchange between the refrigerant and the indoor air. The second heat exchanger 300 is a heat exchanger that functions as an evaporator of the refrigerant during cooling operation and as a radiator of the refrigerant during heating operation. The second drain pan 32 receives water.

[0038] (2) Detailed structure

[0039] (2-1) First heat exchanger

[0040] like Figure 4As shown, the first heat exchanger 200 includes a plurality of first heat transfer tubes 210 and a plurality of first fins 220. The first heat transfer tubes 210 and the first fins 220 are made of aluminum or an aluminum alloy. The first heat exchanger 200 of the present embodiment is a microchannel heat exchanger.

[0041] (2-1-1) First heat transfer tube

[0042] The first heat transfer tube 210 allows the refrigerant to flow inside. Figure 4 and Figure 5 As shown, the first heat transfer tube 210 has a flat shape. Here, the first heat transfer tube 210 is a flat porous tube. In the first heat transfer tube 210, a plurality of through holes are arranged along a predetermined direction for the refrigerant to pass through for heat exchange with outdoor air in the first heat exchanger 200. The plurality of through holes are connected along a first direction. Here, the first direction is a length direction.

[0043] like Figure 5 As shown, the first heat transfer tube 210 has a first base material 211 and a first sacrificial layer 212. The first sacrificial layer 212 is provided on the surface of the first heat transfer tube 210. The first sacrificial layer 212 can be provided on the entire surface of the first heat transfer tube 210, or on a portion of the surface of the first heat transfer tube 210 (not shown). In other words, the first sacrificial layer 212 can be formed on the entire exposed outer surface, or on a portion of the exposed outer surface (not shown). The first sacrificial layer 212 is formed on a portion in the thickness direction from the outer surface of the first heat transfer tube 210 toward the inner surface where the refrigerant flows, and is not formed on the entire wall thickness. In other words, in the first heat transfer tube 210, the first sacrificial layer 212 is not formed on at least a portion of the inner surface where the refrigerant flows. In this embodiment, the first sacrificial layer 212 is not formed on the entire inner surface of the first heat transfer tube 210.

[0044] The potential of the first sacrificial layer 212 is lower than the potential of the first base material 211 of the first heat transfer tube 210 and higher than the potential of the first fin 220. The potential difference between the potential of the first sacrificial layer 212 and the potential of the first base material 211 is, for example, 132 mV. The potential difference between the potential of the first fin 220 and the potential of the first sacrificial layer 212 is, for example, 61 mV. In order to reduce the potential, the first sacrificial layer 212 contains a metal such as zinc (Zn). The first sacrificial layer 212 of this embodiment is a zinc diffusion layer sprayed with zinc. The first sacrificial layer 212 on the outer surface side prevents the corrosion of the first base material 211 on the inner surface side in the first heat transfer tube 210.

[0045] like Figure 4 As shown, the plurality of first heat transfer tubes 210 are arranged in the vertical direction. The lowermost end of the plurality of first heat transfer tubes 210 is located at a position lower than the first drain pan 22 (refer to Figure 2 ) is located at the upper part of the water level.

[0046] (2-1-2) First fin

[0047] The first fin 220 increases the heat transfer area between the first heat transfer tube 210 and the outdoor air, thereby promoting heat exchange between the refrigerant and the outdoor air. The first fin 220 is in contact with the first heat transfer tube 210.

[0048] The potential of the first fin 220 is lower than the potential of the first base material 211 of the first heat transfer tube 210 and lower than the potential of the first sacrificial layer 212. In other words, the order of potential from high to low is the first base material 211, the first sacrificial layer 212 and the first fin 220. The potential difference between the potential of the first fin 220 and the potential of the first base material 211 is, for example, 193 mV.

[0049] In order to reduce the potential, the first fin 220 contains a metal such as zinc. The metal is not particularly limited, and the first fin 220 of the present embodiment contains zinc. The zinc content of the first fin 220 is preferably 2% by mass or more. The upper limit of the zinc content of the first fin 220 is not particularly limited, and is, for example, 6% from the viewpoint of processability.

[0050] Here, the "zinc content" described in this specification is a value measured by, for example, emission spectrometry or the like.

[0051] Furthermore, the first fin 220 of the present embodiment further contains magnesium (Mg) and copper (Cu).

[0052] The plurality of first fins 220 are arranged in a first direction (refer to Figure 4 Here, the plurality of first fins 220 are stacked on the first heat transfer tube 210 (in Figure 4 In the present embodiment, the plurality of first fins 220 are arranged in parallel and at equal intervals. In other words, the plurality of first fins 220 are arranged in the first direction at a predetermined fin pitch P1.

[0053] The first fin 220 is a flat plate-shaped member. In addition, the first fin 220 has a notch for passing the first heat transfer tube 210. The notch is arranged in the first direction. In addition, the first fin 220 may also have a clamp portion.

[0054] (2-1-3) Solder pin

[0055] The first heat exchanger 200 of the outdoor unit 2 may further include a fillet connecting the first heat transfer tube 210 and the first fin 220. The potential of the fillet is not particularly limited, and in this embodiment, the order of potential from high to low is the first base material 211, the first sacrificial layer 212, the fillet, and the first fin 220.

[0056] (2-2) Second heat exchanger

[0057] like Figure 6 As shown, the second heat exchanger 300 includes a plurality of second heat transfer tubes 310 and a plurality of second fins 320. The second heat transfer tubes 310 and the second fins 320 are made of aluminum or an aluminum alloy. The second heat exchanger 300 of the present embodiment is a cross-fin-tube heat exchanger.

[0058] (2-2-1) Second heat transfer tube

[0059] The second heat transfer tube 310 allows the refrigerant to flow inside. The second heat transfer tube 310 has a cylindrical shape. Here, the second heat transfer tube 310 is a round tube. The second heat transfer tube 310 is formed with a through hole for the refrigerant to pass through for heat exchange with the indoor air in the second heat exchanger 300. The through hole of the second heat transfer tube 310 is passed through along the second direction. Here, the second direction is the length direction.

[0060] like Figure 7 As shown, the second heat transfer tube 310 has a second base material 311 and a second sacrificial layer 312. The second sacrificial layer 312 is provided on the surface of the second heat transfer tube 310. The second sacrificial layer 312 can be provided on the entire surface of the second heat transfer tube 310 (not shown), or on a portion of the surface of the second heat transfer tube 310. In other words, the second sacrificial layer 312 can be formed on the entire exposed outer surface (not shown), or on a portion of the exposed outer surface. The second sacrificial layer 312 is formed on a portion in the thickness direction from the outer surface of the second heat transfer tube 310 toward the inner surface where the refrigerant flows, and is not formed on the entire wall thickness. In other words, in the second heat transfer tube 310, the second sacrificial layer 312 is not formed on at least a portion of the inner surface where the refrigerant flows. In this embodiment, the second sacrificial layer 312 is not formed on the entire inner surface of the second heat transfer tube 310.

[0061] The potential of the second sacrificial layer 312 is lower than the potential of the second base material 311 of the second heat transfer tube 310 and lower than the potential of the second fin 320. In order to reduce the potential, the second sacrificial layer 312 contains a metal such as zinc. The second sacrificial layer 312 of this embodiment is a zinc diffusion layer sprayed with zinc. The second sacrificial layer 312 on the outer surface side prevents the corrosion of the second base material 311 on the inner surface side in the second heat transfer tube 310.

[0062] like Figure 6 As shown, the plurality of second heat transfer tubes 310 are arranged in the vertical direction. The lowermost end of the plurality of second heat transfer tubes 310 is located at a position lower than the second drain pan 32 (refer to Figure 3 ) is located at the upper part of the water level.

[0063] (2-2-2) Second fin

[0064] The second fin 320 increases the heat transfer area between the second heat transfer tube 310 and the indoor air, thereby promoting heat exchange between the refrigerant and the indoor air. The second fin 320 is in contact with the second heat transfer tube 310 .

[0065] The potential of the second fin 320 is lower than the potential of the second base material 311 of the second heat transfer tube 310 and higher than the potential of the second sacrificial layer 312. In other words, the order of potential from high to low is the second base material 311, the second fin 320 and the second sacrificial layer 312.

[0066] In order to reduce the potential, the second fin 320 contains a metal such as zinc. The second fin 320 may contain zinc or may not contain zinc. Specifically, the zinc content of the second fin 320 is, for example, 0 mass % or more and 1 mass % or less.

[0067] The plurality of second fins 320 extend in the second direction (refer to Figure 6 Here, the plurality of second fins 320 are stacked on the second heat transfer tube 310 (in Figure 6 In the present embodiment, the plurality of second fins 320 are arranged in parallel and at equal intervals. In other words, the plurality of second fins 320 are arranged in the second direction at a predetermined fin pitch P2.

[0068] like Figure 8 and Fig. 9 As shown, the plurality of second fins 320 include a fin body 321 and a second clamp portion 322. The fin body 321 is a flat plate-shaped component. The second clamp portion 322 allows the second heat transfer tube 310 to pass through. Specifically, the second clamp portion 322 has a through hole for allowing the second heat transfer tube 310 to pass through.

[0069] The second clamp portion 322 includes a first rising portion 323, a flat portion 324, a second rising portion 325, and a flange portion 326. The first rising portion 323, the flat portion 324, the second rising portion 325, and the flange portion 326 are formed by one component. Here, the first rising portion 323, the flat portion 324, the second rising portion 325, and the flange portion 326 are formed by nesting.

[0070] The first rising portion 323 extends from the fin body 321 in the second direction. Here, the first rising portion 323 is orthogonal to the fin body 321. The connection portion between the first rising portion 323 and the fin body 321 has a curved (R) shape.

[0071] The flat portion 324 extends from the first rising portion 323 toward the second heat transfer tube 310. Here, the flat portion 324 is orthogonal to the first rising portion 323. The connection portion between the flat portion 324 and the first rising portion 323 has a curved shape.

[0072] The second rising portion 325 extends from the flat portion 324 along the second heat transfer tube 310. The second rising portion 325 contacts the second heat transfer tube 310. Here, the second rising portion 325 is orthogonal to the flat portion 324. The connection portion between the second rising portion 325 and the flat portion 324 has a curved shape.

[0073] The flange portion 326 extends outward from the second rising portion 325. Here, the flange portion 326 is orthogonal to the second rising portion 325. The connection portion between the flange portion 326 and the second rising portion 325 has a curved shape.

[0074] One flat portion 324 contacts the flange portion 326 of another adjacent second fin 320. The flat portion 324 and the flange portion 326 extend in the same direction.

[0075] As described above, the second fin 320 of the present embodiment is required to have high processability.

[0076] (2-3) Relationship between the first fin and the second fin

[0077] Next, the relationship between the first fins 220 of the first heat exchanger 200 and the second fins 320 of the second heat exchanger 300 will be described.

[0078] (2-3-1) Elongation

[0079] The elongation of the second fin 320 is greater than the elongation of the first fin 220. Here, the "elongation" of the present disclosure is based on JIS H4000.

[0080] (2-3-2) Zinc content

[0081] The zinc content of the first fin 220 is higher than the zinc content of the second fin 320. For example, the zinc content of the first fin 220 is higher than the zinc content of the second fin 320 by 1 mass % or more.

[0082] (2-3-3) Potential

[0083] The potential of the first fin 220 is lower than the potential of the second fin 320. For example, the potential of the first fin 220 is lower than the potential of the second fin 320 by 10 mV or more. The potential is adjusted by, for example, the type, content, and amount of the metal having a low potential.

[0084] (2-3-4) Spacing

[0085] Figure 6 The fin pitch P2 of the second fin 320 shown is larger than Figure 4The fin pitch P1 of the first fin 220 shown is large. Here, the fin pitch P1 is the distance between adjacent first fins 220. In detail, the fin pitch P1 is the distance between the opposing surfaces of adjacent first fins 220. Similarly, the fin pitch P2 is the distance between adjacent second fins 320. In detail, the fin pitch P2 is the distance between the opposing surfaces of adjacent second fins 320.

[0086] The difference between the fin pitch P1 of the first fins 220 and the fin pitch P2 of the second fins 320 is 0.1 mm or more and 0.3 mm or less. In other words, the pitch difference (fin pitch P2 - fin pitch P1) is 0.1 mm or more and 0.3 mm or less.

[0087] The fin pitch P1 of the first fins 220 is, for example, not less than 1.2 mm and not more than 1.4 mm. The fin pitch P2 of the second fins 320 is, for example, not less than 1.3 mm and not more than 1.5 mm.

[0088] (3) Features

[0089] (3-1)

[0090] The air conditioner 1 of the present embodiment includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 includes a first heat exchanger 200. The first heat exchanger 200 includes a first heat transfer tube 210 and a plurality of first fins 220. The first heat transfer tube 210 is made of aluminum or an aluminum alloy. The plurality of first fins 220 are made of aluminum or an aluminum alloy. The indoor unit 3 includes a second heat exchanger 300. The second heat exchanger 300 includes a second heat transfer tube 310 and a plurality of second fins 320. The second heat transfer tube 310 is made of aluminum or an aluminum alloy. The plurality of second fins 320 are made of aluminum or an aluminum alloy. A first sacrificial layer 212 is provided on the surface of the first heat transfer tube 210. The potential of the first sacrificial layer 212 is lower than the potential of the first base material 211 of the first heat transfer tube 210 and higher than the potential of the first fin 220. The first fin 220 contains zinc. The zinc content of the first fin 220 is higher than the zinc content of the second fin 320.

[0091] According to the air conditioner 1 of the present embodiment, the first heat transfer tube 210 made of aluminum or aluminum alloy is provided with the first sacrificial layer 212 having a lower potential than the first base material 211, so that the corrosion of the first base material 211 can be suppressed. In addition, since the potential of the first sacrificial layer 212 is higher than the potential of the first fin 220, the corrosion of the first sacrificial layer 212 for suppressing the corrosion of the first base material 211 can be suppressed.

[0092] However, if zinc is contained in order to lower the electric potential of the first fin 220 and the second fin 320, the first fin 220 and the second fin 320 will solidify, and thus the workability will be deteriorated. The inventor of the present invention focused on the fact that the second fin 320 of the indoor unit 3 is difficult to process due to reasons such as compactness and bending. In other words, the inventor of the present invention focused on the fact that the first fin 220 of the outdoor unit 2 does not require workability compared to the second fin 320 of the indoor unit 3. Therefore, in the air conditioner 1 of the present embodiment, the zinc content of the first fin 220 is made higher than the zinc content of the second fin 320. Thus, the workability of the second fin 320 of the indoor unit 3 can be ensured, and therefore, the second heat exchanger 300 having the second fin 320 can be used for the indoor unit 3.

[0093] (3-2)

[0094] In the air conditioner 1 of the present embodiment, the zinc content of the first fin 220 is 2 mass % or more. This can realize the first sacrificial layer 212 having a potential that can suppress corrosion of the first base material 211 .

[0095] (3-3)

[0096] In the air conditioner 1 of the present embodiment, the fin pitch P2 of the second fins 320 is larger than the fin pitch P1 of the first fins 220 .

[0097] The second fin 320 has a lower zinc content than the first fin 220, so it is easy to corrode. Therefore, here, by making the fin pitch P2 of the second fin 320 larger than the fin pitch P1 of the first fin 220, the number of second fins 320 can be reduced, and the surface area of ​​the second fin 320 in contact with the second heat transfer tube 310 can be reduced. Therefore, the corrosion of the second fin 320 can be suppressed.

[0098] In addition, as described above, high workability is required for the second fins 320 of the indoor unit 3. Therefore, by reducing the number of the second fins 320, the burden associated with the work can be reduced.

[0099] Furthermore, by reducing the fin pitch P1 of the first fins 220 of the first heat exchanger 200 of the outdoor unit 2, it is possible to ensure a large number of first fins 220. Therefore, it is possible to suppress a reduction in the overall performance of the air conditioner 1.

[0100] In addition, in the outdoor unit 2 which is greatly affected by salt damage, the area of ​​the first fin 220 which is sacrificed for the first heat transfer tube 210 can be increased. Therefore, the corrosion of the first heat transfer tube 210 can be further suppressed.

[0101] (3-4)

[0102] In the air conditioner 1 of the present embodiment, the difference (P2-P1) between the fin pitch P1 of the first fin 220 and the fin pitch P2 of the second fin 320 is 0.1 mm or more and 0.3 mm or less. This can further suppress corrosion of the second fin 320.

[0103] (3-5)

[0104] In the air conditioner 1 of the present embodiment, the potential of the first fin 220 is lower than the potential of the second fin 320 .

[0105] The first heat exchanger 200 of the outdoor unit 2 is more susceptible to salt damage than the second heat exchanger 300 of the indoor unit 3. Therefore, here, by making the potential of the first fin 220 lower than the potential of the second fin 320, the first fin 220 becomes a sacrifice of the first heat transfer tube 210, thereby further suppressing the corrosion of the first heat transfer tube 210.

[0106] (3-6)

[0107] In the air conditioner 1 of the present embodiment, the second sacrificial layer 312 having a lower potential than the second base material 311 of the second heat transfer tube 310 and lower potential than the second fin 320 is provided on the surface of the second heat transfer tube 310 .

[0108] The second heat exchanger 300 of the indoor unit 3 is less susceptible to salt damage than the first heat exchanger 200 of the outdoor unit 2. Therefore, even if the potential of the second sacrificial layer 312 of the indoor unit 3 is lower than the potential of the second fin 320, corrosion of the second base material 311 can be suppressed. In addition, reduction in the workability of the second fin 320 can be further suppressed.

[0109] (3-7)

[0110] In the air conditioner 1 of the present embodiment, the first heat transfer tube 210 has a flat shape, and the second heat transfer tube 310 has a cylindrical shape.

[0111] The second fin 320 attached to the cylindrical second heat transfer tube 310 requires higher workability than the first fin 220 attached to the flat first heat transfer tube 210. Thus, the second heat transfer tube 310 of the indoor unit 3 requires higher workability than the first heat transfer tube 210 of the outdoor unit 2. Therefore, it can be applied to the air conditioner 1 including the first heat exchanger 200 having the flat first heat transfer tube 210 and the second heat exchanger 300 having the cylindrical second heat transfer tube 310.

[0112] (3-8)

[0113] The air conditioner 1 of the present embodiment includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 includes a first heat exchanger 200. The first heat exchanger 200 includes a first heat transfer tube 210 and a plurality of first fins 220. The first heat transfer tube 210 is made of aluminum or an aluminum alloy. The plurality of first fins 220 are made of aluminum or an aluminum alloy. The indoor unit 3 includes a second heat exchanger 300. The second heat exchanger 300 includes a second heat transfer tube 310 and a plurality of second fins 320. The second heat transfer tube 310 is made of aluminum or an aluminum alloy. The plurality of second fins 320 are made of aluminum or an aluminum alloy. A first sacrificial layer 212 is provided on the surface of the first heat transfer tube 210. The potential of the first sacrificial layer 212 is lower than the potential of the first base material 211 of the first heat transfer tube 210 and higher than the potential of the first fin 220. The elongation of the second fin 320 is greater than the elongation of the first fin 220.

[0114] According to the air conditioner 1 of the present embodiment, the first heat transfer tube 210 made of aluminum or aluminum alloy is provided with the first sacrificial layer 212 having a lower potential than the first base material 211, so that the corrosion of the first base material 211 can be suppressed. In addition, since the potential of the first sacrificial layer 212 is higher than the potential of the first fin 220, the corrosion of the first sacrificial layer 212 for suppressing the corrosion of the first base material 211 can be suppressed.

[0115] However, if the potential of the first fin 220 and the second fin 320 is lowered, the first fin 220 and the second fin 320 are solidified, and thus the workability is deteriorated. Therefore, in the air conditioner 1 of the present embodiment, the first fin 220 of the outdoor unit 2 is not required to have workability compared with the second fin 320 of the indoor unit 3, and the elongation of the second fin 320 is made greater than the elongation of the first fin 220. Thus, the workability of the second fin 320 of the indoor unit 3 can be ensured, and therefore the second heat exchanger 300 having the second fin 320 can be used for the indoor unit 3.

[0116] (4) Modification

[0117] (4-1) Modification 1

[0118] In the above embodiment, the first sacrificial layer 212 of the first heat transfer tube 210 and the second sacrificial layer 312 of the second heat transfer tube 310 are described as diffusion layers sprayed with zinc, but the present invention is not limited thereto. In this modification, a cladding material is used as the base material and the sacrificial layer.

[0119] Specifically, the first heat transfer tube 210 is formed using a cladding material formed by laminating a metal as the first base material 211 and a metal as the first sacrificial layer 212. The second heat transfer tube 310 is formed using a cladding material formed by laminating a metal as the second base material 311 and a metal as the second sacrificial layer 312.

[0120] (4-2) Modification 2

[0121] In the above-mentioned embodiment, in the second heat exchanger 300 of the indoor unit 3, the potential is from high to low in the order of the second base material 311, the second fin 320 and the second sacrificial layer 312, but it is not limited thereto. In this modified example, in the second heat exchanger 300 of the indoor unit 3, the potential is from high to low in the order of the second base material 311, the second sacrificial layer 312 and the second fin 320.

[0122] (4-3) Modification 3

[0123] In the above-mentioned embodiment and modified examples 1 and 2, the second heat transfer tube 310 of the indoor unit 3 has the second sacrificial layer 312, but in this modified example, the second sacrificial layer 312 is omitted. Even in this case, since the potential of the second heat transfer tube 310 is higher than the potential of the second fin 320, corrosion of the second heat transfer tube 310 can be suppressed.

[0124] (4-4) Modification 4

[0125] In the above-mentioned embodiment, the first heat exchanger 200 is a microchannel heat exchanger, and the second heat exchanger 300 is a cross-fin tube heat exchanger, but the present invention is not limited thereto. The first heat exchanger 200 may also be a cross-fin tube heat exchanger, and the second heat exchanger 300 may also be a microchannel heat exchanger. In the case where both the first heat exchanger 200 and the second heat exchanger 300 are microchannel heat exchangers or cross-fin heat exchangers, the first heat transfer tube 210 and the second heat transfer tube 310 can be made common.

[0126] As mentioned above, although embodiment of this disclosure is described, it should be understood that various changes in form and detail are possible without departing from the spirit and scope of this disclosure described in the claims.

[0127] Description of symbols

[0128] 1 Air conditioner

[0129] 2Outdoor unit

[0130] 3Indoor unit

[0131] 200 First Heat Exchanger

[0132] 210 first heat transfer tube

[0133] 211 First parent material (parent material)

[0134] 212 first sacrificial layer

[0135] 220 First Fin

[0136] 300 Second heat exchanger

[0137] 310 second heat transfer tube

[0138] 311 Second parent material (parent material)

[0139] 312 Second Sacrificial Layer

[0140] 320 Second Fin

[0141] P1, P2 fin spacing

[0142] Prior art literature

[0143] Patent Literature

[0144] Patent Document 1: International Publication No. 2017 / 141943

Claims

1. An air conditioner (1), comprising: An outdoor unit (2) comprises a first heat exchanger (200), wherein the first heat exchanger (200) has a first heat transfer tube (210) made of aluminum or an aluminum alloy and a plurality of first fins (220) made of aluminum or an aluminum alloy; and The indoor unit (3) comprises a second heat exchanger (300), wherein the second heat exchanger (300) has a second heat transfer tube (310) made of aluminum or an aluminum alloy and a plurality of second fins (320) made of aluminum or an aluminum alloy. A first sacrificial layer (212) having a potential lower than that of a base material (211) of the first heat transfer tube and higher than that of the first fin is provided on the surface of the first heat transfer tube. The first fin contains zinc, The zinc content of the first fin is higher than the zinc content of the second fin.

2. The air conditioner according to claim 1, wherein: The zinc content of the first fin is 2 mass % or more.

3. The air conditioner according to claim 1 or 2, wherein: The fin pitch (P2) of the second fins is greater than the fin pitch (P1) of the first fins.

4. The air conditioner according to claim 3, wherein: A difference between a fin pitch of the first fins and a fin pitch of the second fins is greater than or equal to 0.1 mm and less than or equal to 0.3 mm.

5. The air conditioner according to any one of claims 1 to 4, wherein: The potential of the first fin is lower than the potential of the second fin.

6. The air conditioner according to any one of claims 1 to 5, wherein: A second sacrificial layer (312) having a potential lower than that of a base material (311) of the second heat transfer tube and lower than that of the second fin is provided on the surface of the second heat transfer tube.

7. The air conditioner according to any one of claims 1 to 6, wherein: The first heat transfer tube has a flat shape, The second heat transfer tube has a cylindrical shape.

8. An air conditioner (1), comprising: An outdoor unit (2) comprises a first heat exchanger (200), wherein the first heat exchanger (200) has a first heat transfer tube (210) made of aluminum or an aluminum alloy and a plurality of first fins (220) made of aluminum or an aluminum alloy; and The indoor unit (3) comprises a second heat exchanger (300), wherein the second heat exchanger (300) has a second heat transfer tube (310) made of aluminum or an aluminum alloy and a plurality of second fins (320) made of aluminum or an aluminum alloy. A first sacrificial layer (212) having a potential lower than that of a base material (211) of the first heat transfer tube and higher than that of the first fin is provided on the surface of the first heat transfer tube. The elongation rate of the second fin is greater than the elongation rate of the first fin.

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