CN115516269A

CN115516269A - Heat exchanger and air conditioner

Info

Publication number: CN115516269A
Application number: CN202080100232.8A
Authority: CN
Inventors: 足立理人; 尾中洋次; 七种哲二
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-05-22
Filing date: 2020-05-22
Publication date: 2022-12-23
Also published as: JPWO2021234964A1; JP7292510B2; EP4155652A1; EP4155652A4; US20230101157A1; WO2021234964A1

Abstract

The heat exchanger is provided with: the refrigerant-cooling device includes a plurality of flat tubes through which a refrigerant flows, and a plurality of fins provided between the flat tubes and transmitting heat of the refrigerant flowing through the flat tubes, wherein upstream-side ends of the flat tubes in an air flow are located at the same positions as or protrude from upstream-side ends of the fins, and openings are formed at the upstream-side ends of the flat tubes or the upstream-side ends of the fins.

Description

Heat exchanger and air conditioner

Technical Field

The present disclosure relates to a heat exchanger and an air conditioner including flat tubes and fins.

Background

Conventionally, a heat exchanger including flat tubes and fins is known. Patent document 1 discloses a heat exchanger including a plurality of flat tubes and a corrugated fin provided with a plurality of louvers. In patent document 1, the upstream end of the fin in the air flow is an extension portion protruding from the upstream end of the flat tube. In general, the air that has undergone heat exchange on the upstream side of the fins is deprived of thermal energy or cooling energy by an amount corresponding to the heat exchange, and therefore the amount of heat exchange on the downstream side is reduced. In patent document 1, the upstream end portions of the fins protrude beyond the upstream end portions of the flat tubes, and therefore the area of the fins in contact with the flat tubes on the upstream side is small. Thus, patent document 1 aims to reduce the amount of heat exchange on the upstream side, thereby suppressing a decrease in the amount of heat exchange on the downstream side, and thereby achieving a balance between the amount of heat exchange on the upstream side and the amount of heat exchange on the downstream side.

Patent document 1: japanese patent No. 5563162

However, in the heat exchanger disclosed in patent document 1, the upstream side end portions of the fins protrude beyond the upstream side end portions of the flat tubes, and therefore the strength of the fins is reduced.

Disclosure of Invention

The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide a heat exchanger and an air conditioner that achieve a balance between the amount of heat exchange on the upstream side and the amount of heat exchange on the downstream side, and that ensure fin strength.

The heat exchanger of the present disclosure includes: a plurality of flat tubes through which a refrigerant flows; and a plurality of fins which are provided between the flat tubes and which transfer heat of the refrigerant flowing through the flat tubes, wherein upstream end portions of the flat tubes, through which air flows, are located at the same positions as or protrude beyond the upstream end portions of the fins, and openings are formed at the upstream end portions of the flat tubes or the upstream end portions of the fins.

According to the present disclosure, the upstream end portion of the flat tube in the air flow is located at the same position as the upstream end portion of the fin, or protrudes beyond the upstream end portion of the fin. Therefore, the strength of the fin can be ensured. Further, openings are formed at the upstream end portions of the flat tubes or the upstream end portions of the fins. This makes it possible to equalize the amount of heat exchange on the upstream side and the amount of heat exchange on the downstream side of the fin. That is, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side can be balanced, and the strength of the fin can be ensured.

Drawings

Fig. 1 is a circuit diagram showing an air conditioner according to embodiment 1.

Fig. 2 is a front view showing a heat exchanger according to embodiment 1.

Fig. 3 is a sectional view showing a flat tube and a fin according to embodiment 1.

Fig. 4 is a sectional view showing a flat tube and a fin according to embodiment 2.

Fig. 5 is a cross-sectional view showing a flat tube and a fin according to embodiment 3.

Fig. 6 is a sectional view showing a flat tube and a fin according to embodiment 3.

Fig. 7 is a cross-sectional view showing a flat tube and a fin according to a modification of embodiment 3.

Fig. 8 is a sectional view showing a flat tube and a fin according to embodiment 4.

Fig. 9 is a front view showing a heat exchanger according to embodiment 5.

Fig. 10 is a sectional view showing a flat tube and a fin according to embodiment 5.

Fig. 11 is a cross-sectional view showing a flat tube and a fin according to a modification of embodiment 5.

Fig. 12 is a sectional view showing a flat tube and a fin according to embodiment 6.

Detailed Description

Embodiments of the heat exchanger and the air conditioner according to the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to the embodiments described below. In the following drawings, including fig. 1, the relationship between the sizes of the respective components may be different from the actual one. In the following description, terms indicating directions are used as appropriate in order to facilitate understanding of the present disclosure, but these terms are used for description of the present disclosure and do not limit the present disclosure. Examples of words indicating directions include "up", "down", "right", "left", "front", and "rear". In some of the drawings, hatching in the cross-sectional view is partially omitted.

Embodiment 1.

Fig. 1 is a circuit diagram showing an air conditioner 1 according to embodiment 1. As shown in fig. 1, an air conditioner 1 is a device for adjusting 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 switching device 7, a heat exchanger 8, an outdoor fan 9, and an expansion unit 10. The indoor unit 3 is provided with an indoor heat exchanger 11 and an indoor fan 12.

The compressor 6, the flow path switching device 7, the heat exchanger 8, the expansion unit 10, and the indoor heat exchanger 11 are connected by refrigerant pipes 5, and constitute a refrigerant circuit 4 through which a refrigerant as a working gas flows. The compressor 6 sucks a refrigerant in a low-temperature and low-pressure state, compresses the sucked refrigerant to a high-temperature and high-pressure refrigerant, and discharges the refrigerant. The flow switching device 7 is, for example, a four-way valve for switching the direction of the refrigerant flow in the refrigerant circuit 4. The heat exchanger 8 exchanges heat between outdoor air and refrigerant, for example. The heat exchanger 8 functions as a condenser during the cooling operation and functions as an evaporator during the heating operation.

The outdoor blower 9 is a device that sends outdoor air to the heat exchanger 8. The expansion unit 10 is a pressure reducing valve or an expansion valve that reduces the pressure of the refrigerant and expands the refrigerant. The expansion unit 10 is, for example, an electronic expansion valve whose opening degree can be adjusted. The indoor heat exchanger 11 exchanges heat between, for example, indoor air and refrigerant. The indoor heat exchanger 11 functions as an evaporator during the cooling operation and functions as a condenser during the heating operation. The indoor fan 12 is a device that sends indoor air to the indoor heat exchanger 11.

(operation mode, cooling operation)

Next, an operation mode of the air conditioner 1 will be described. First, the cooling operation will be described. In the cooling operation, the refrigerant sucked into the compressor 6 is compressed by the compressor 6 and discharged in a high-temperature and high-pressure gas state. The high-temperature and high-pressure refrigerant in a gas state discharged from the compressor 6 flows into the heat exchanger 8 functioning as a condenser through the flow switching device 7, and is condensed and liquefied in the heat exchanger 8 by heat exchange with the outdoor air sent by the outdoor air-sending device 9. The condensed refrigerant in the liquid state flows into the expansion unit 10, is expanded and decompressed in the expansion unit 10, and turns into a low-temperature and low-pressure refrigerant in a gas-liquid two-phase state. Then, the two-phase gas-liquid refrigerant flows into the indoor heat exchanger 11 functioning as an evaporator, and exchanges heat with the indoor air sent by the indoor air-sending device 12 in the indoor heat exchanger 11 to be evaporated and gasified. At this time, the indoor air is cooled and cooled in the room. The evaporated low-temperature low-pressure refrigerant in a gas state is sucked into the compressor 6 through the flow switching device 7.

(operation mode, heating operation)

Next, the heating operation will be described. In the heating operation, the refrigerant sucked into the compressor 6 is compressed by the compressor 6 and discharged in a high-temperature and high-pressure gas state. The high-temperature and high-pressure refrigerant in a gas state discharged from the compressor 6 passes through the flow switching device 7, flows into the indoor heat exchanger 11 functioning as a condenser, exchanges heat with the indoor air sent by the indoor air-sending device 12 in the indoor heat exchanger 11, and is condensed and liquefied. At this time, the indoor air is heated, and heating is performed in the room. The condensed refrigerant in the liquid state flows into the expansion section 10, and is expanded and decompressed in the expansion section 10 to become a low-temperature and low-pressure refrigerant in a gas-liquid two-phase state. The two-phase gas-liquid refrigerant then flows into the heat exchanger 8 functioning as an evaporator, and is evaporated and gasified in the heat exchanger 8 by heat exchange with the outdoor air sent by the outdoor air-sending device 9. The evaporated low-temperature low-pressure refrigerant in a gas state is sucked into the compressor 6 through the flow switching device 7.

Fig. 2 is a front view showing a heat exchanger 8 according to embodiment 1. 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. The heat exchanger 8 may be a fin-and-tube heat exchanger. The heat exchanger 8 includes flat tubes 20, fins 30, and a header 40. The flat tubes 20 are tubes through which a refrigerant flows, and are made of aluminum or an aluminum alloy in which a plurality of tubes are arranged. In addition, a clad material using aluminum as a core material may be used for the flat tube 20. The flat tubes 20 are formed by, for example, forming a plurality of flow passages 21 (see fig. 3) through which a refrigerant flows in a row.

The fins 30 are members for transmitting heat of the refrigerant flowing through the flat tubes 20, and are, for example, corrugated fins arranged between the flat tubes 20 and the flat tubes 20 while being bent. The fins 30 have inclined surfaces 30a (see fig. 3) inclined with respect to the horizontal direction and are alternately folded back. Between the fins 30 and the flat tubes 20, ventilation passages 31 are formed through which air flows. The fins 30 are made of aluminum, for example. Further, the fins 30 may be plate fins. The header 40 is made of, for example, aluminum, and allows the refrigerant to flow therein and to branch off the refrigerant to the plurality of flat tubes 20 connected thereto. As described above, the fin 30 may be made of the same material as the flat tube 20 or may be made of a different material.

The header 40 includes a header 40 to which one end portions of the plurality of flat tubes 20 are connected, and a header 40 to which the other end portions of the plurality of flat tubes 20 are connected. The header 40 may be configured such that the flow path 21 through which the refrigerant flows is partitioned by one or more partitions. The refrigerant pipe 5 is connected to one of the headers 40, and the header 40 is connected to the flow switching device 7 through the refrigerant pipe 5. The refrigerant pipe 5 is connected to the other header 40, and the header 40 is connected to the expansion unit 10 through the refrigerant pipe 5. The header 40 may be made of the same material as the flat tubes 20.

Fig. 3 isbase:Sub>A cross-sectional view of the flat tube 20 and the fin 30 according to embodiment 1, and isbase:Sub>A view showingbase:Sub>A part ofbase:Sub>A cross-sectionbase:Sub>A-base:Sub>A in fig. 2. In fig. 3, the air flows from above downward. As shown in fig. 3, the fin 30 is provided between the flat tubes 20, and includes a plurality of louvers 32 provided on the inclined surface 30 a. Here, in the fin 30, the planar portion without the louver 32 is wider on the upstream side than on the downstream side of the air flow. A rectangular slit 33 is formed in the middle of the louvers 32.

Two holes 34, which are rectangular openings 50 extending in the longitudinal direction of the fin 30, are formed in the upstream end of the fin 30. Specifically, the hole 34 is formed at a position on the upstream side of 3/4L from the downstream end with respect to the entire length L of the fin 30 in the longitudinal direction. Thus, the heat transfer area of the upstream end portion of the fin 30 where the air flows is smaller than that of the downstream end portion. The downstream end of the fin 30 is flush with the downstream end of the flat tube 20. The downstream end of the fin 30 may be located upstream of the downstream end of the flat tube 20. The upstream-side end portions of the flat tubes 20 are located at the same positions as the upstream-side end portions of the fins 30.

According to embodiment 1, the upstream end of the flat tube 20 in the air flow is located at the same position as the upstream end of the fin 30. Since the fins 30 do not protrude from the flat tubes 20, the fins 30 can be prevented from falling down during manufacturing or transportation. Therefore, the strength of the fin 30 can be ensured. Further, an opening 50 is formed at an upstream end portion of the fin 30. This can equalize the amount of heat exchange between the upstream side and the downstream side of the fin 30. That is, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side can be balanced, and the strength of the fin 30 can be ensured.

Further, a hole 34 as an opening 50 is formed at an upstream end of the fin 30. In general, the air heat-exchanged on the upstream side of the fins 30 is deprived of the thermal energy or the cold energy according to the heat exchange, and therefore the amount of heat exchange on the downstream side is reduced. In embodiment 1, since the holes 34 as the openings 50 are formed in the upstream end portions of the fins 30, the heat transfer area of the upstream end portions, through which the air flows, is smaller than that of the downstream end portions in the fins 30. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 30 can be balanced. As described above, in embodiment 1, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 30 are balanced, and the strength of the fin 30 can be ensured.

Conventionally, a technique is known in which the upstream end of the fin in the air flow is an extension portion protruding from the upstream end of the flat tube. In this case, the fins of the protruding portion may fall down during manufacturing or transportation to deteriorate the heat transfer performance. When the fins are formed with slits for drainage, the strength of the fins is further reduced, and the possibility of the fins falling down is increased. In addition, when the extension portions of the fins are to be eliminated, the heat transfer area on the upstream side of the fins is increased, and therefore, frost is likely to form on the upstream side of the fins. Thus, frost resistance is lowered.

In contrast, in embodiment 1, the upstream end portions of the flat tubes 20 are located at the same positions as the upstream end portions of the fins 30, and holes 34 as the openings 50 are formed in the upstream end portions of the fins 30. This can equalize the amount of heat exchange on the upstream side and the amount of heat exchange on the downstream side of the fin 30, and ensure the strength of the fin 30.

Further, since the holes 34 as the openings 50 are formed in the upstream end portion of the fin 30, heat transfer on the upstream side of the fin 30 can be suppressed, and uneven frost formation can be suppressed. This can suppress the blockage of the ventilation passage 31 through which air flows. In addition, the condensed water adheres to the condensed water passing holes 34 of the fins 30, whereby drainage can be improved.

Embodiment 2.

Fig. 4 is a sectional view showing the flat tube 20 and the fin 130 according to embodiment 2. The heat exchanger 108 according to embodiment 2 is different from embodiment 1 in that the opening 50 is a gap 134 formed between the fin 130 and the flat tube 20 at the upstream end portion thereof. In embodiment 2, the same reference numerals are given to the same portions as those in embodiment 1, and the description thereof is omitted, and the differences from embodiment 1 will be mainly described.

As shown in fig. 4, the width of the upstream end of the fin 130 is narrower than the downstream end. Thereby, gaps 134 are formed between the upstream end portions of the fins 130 and the flat tubes 20. The upstream end portions of the flat tubes 20 are located at the same positions as the upstream end portions of the fins 130, as in embodiment 1.

According to embodiment 2, the upstream end of the flat tube 20 is located at the same position as the upstream end of the fin 130. Since the fins 130 do not protrude from the flat tubes 20, the fins 130 can be prevented from falling down during manufacturing or transportation. That is, the strength of the fin 130 can be ensured. Further, since the upstream end of the fin 130 has the gap 134 with the flat tube 20, the heat transfer area of the upstream end of the fin 130 where the air flows is smaller than that of the downstream end. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 130 can be balanced. Thus, in embodiment 2, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 130 are balanced, and the strength of the fin 130 can be ensured.

Further, since the gaps 134 are formed between the upstream end portions of the fins 130 and the flat tubes 20, heat transfer on the upstream side of the fins 130 can be suppressed, and uneven frost formation can be suppressed. This can prevent the air passage 31 through which air flows from being blocked by frost. In addition, the condensed water attached to the fins 130 passes through the gaps 134, thereby improving drainage.

Embodiment 3.

Fig. 5 is a sectional view showing the flat tube 220 and the fin 230 according to embodiment 3. The heat exchanger 208 according to embodiment 3 is different from embodiment 1 in that the opening 50 is a gap 234 formed between the fin 230 and the flat tube 220 at the upstream end portion thereof. In embodiment 3, the same reference numerals are given to the same portions as those in embodiments 1 and 2, and the description thereof is omitted, and the differences from embodiments 1 and 2 will be mainly described.

As shown in fig. 5, the upstream end of the flat tube 220 is narrower than the downstream end. The upstream end of the flat tube 220 is thin and curved. Thereby, a gap 234 is formed between the upstream-side end portion of the fin 230 and the flat tube 220. The upstream end of the flat tube 220 protrudes beyond the upstream end of the fin 230.

According to embodiment 3, the upstream end of the flat tube 220 protrudes beyond the upstream end of the fin 230. Since the fins 230 do not protrude from the flat tubes 220, the fins 230 can be prevented from falling down during manufacturing or transportation. That is, the strength of the fin 230 can be ensured. Further, since the upstream end of the fin 230 has the gap 234 formed between the fin and the flat tube 220, the heat transfer area of the upstream end of the fin 230 through which the air flows is smaller than that of the downstream end. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 230 can be equalized. Thus, in embodiment 3, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 230 are balanced, and the strength of the fin 230 can be ensured.

Further, since the gaps 234 are formed between the upstream end portions of the fins 230 and the flat tubes 220, heat transfer on the upstream side of the fins 230 can be suppressed, and uneven frost formation can be suppressed. This can prevent the air passage 31 through which air flows from being blocked by frost. Further, the condensed water attached to the fins 230 passes through the gaps 234, thereby improving drainage. Further, the flat tubes 220 have curved front ends, which can reduce ventilation resistance.

Fig. 6 is a sectional view showing a flat tube 220 and a fin 230 according to embodiment 3. In embodiment 3, a case where two rows of flat tubes 220 are arranged in a row direction parallel to the direction in which air flows is exemplified. In this case, as shown in fig. 6, the tips of the upstream flat tubes 220 are tapered, and the tips of the downstream flat tubes 220 are not tapered. This is because the heat transfer to the fins 230 is already sufficiently performed at the downstream-side end portions of the upstream-side flat tubes 220, and therefore, it is not necessary to taper the leading ends of the downstream-side flat tubes 220.

(modification example)

Fig. 7 is a cross-sectional view showing a flat tube 220a and a fin 230a according to a modification of embodiment 3. As shown in fig. 7, in the heat exchanger 208a of the modification, a portion adjacent to the fin 230a on the upstream end portion side of the flat tube 220a is a gap 234a that is cut out. In the modification, since the upstream end of the fin 230a has the gap 234a between the fin and the flat tube 220a, the heat transfer area of the upstream end of the fin 230a through which air flows is smaller than that of the downstream end. Therefore, the modification can achieve a balance between the amount of heat exchange on the upstream side and the amount of heat exchange on the downstream side of the fin 230 a.

Embodiment 4.

Fig. 8 is a sectional view showing the flat tube 20 and the fin 330 according to embodiment 4. The heat exchanger 308 of embodiment 4 is different from embodiments 1 to 3 in that it includes a reinforcing portion 360 for reinforcing the fin 330. In embodiment 4, the same reference numerals are given to the same portions as those in embodiments 1 to 3, and the description thereof is omitted, and the differences from embodiments 1 to 3 will be mainly described.

As shown in fig. 8, the upstream end portions of the fins 330 protrude beyond the upstream end portions of the flat tubes 20. The reinforcing portion 360 is provided between the portions of the fins 330 protruding from the flat tubes 20. The reinforcing portion 360 is made of, for example, resin having a large thermal resistance.

According to embodiment 4, the fins 330 protrude from the flat tubes 20, but the reinforcing portions 360 are provided between the portions of the fins 330 that protrude from the flat tubes 20, and therefore the fins 330 can be prevented from falling over during manufacturing or transportation. That is, the strength of the fin 330 can be ensured. Further, since the upstream end of the fin 330 is not in contact with the flat tubes 20, the heat transfer area of the upstream end of the fin 330 through which air flows is smaller than that of the downstream end. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 330 can be balanced. Thus, in embodiment 4, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 330 are balanced, and the strength of the fin 330 can be ensured.

Further, since the upstream end portions of the fins 330 do not contact the flat tubes 20, heat transfer on the upstream side of the fins 330 can be suppressed, and uneven frost formation can be suppressed. This can prevent the air passage 31 through which air flows from being blocked by frost. Further, the condensed water attached to the fins 330 flows along the reinforcing portion 360 as a resin, thereby improving drainage.

Embodiment 5.

Fig. 9 is a front view showing a heat exchanger 408 according to embodiment 5, and fig. 10 is a sectional view showing a flat tube 20 and a fin 430 according to embodiment 5. Embodiment 5 is different from embodiments 1 to 4 in that a reinforcing portion 434 is formed in the fin 430. In embodiment 5, the same reference numerals are given to the same portions as those in embodiments 1 to 4, and the description thereof is omitted, and the differences from embodiments 1 to 4 will be mainly described.

As shown in fig. 9 and 10, a plurality of reinforcing portions 434 for reinforcing the fin 430 are formed at the upstream end portion of the inclined surface 30a of the fin 430. The reinforcing portion 434 bends the fin 430 into a rectangular shape and a concave-convex shape. The upstream end of the fin 430 protrudes beyond the upstream end of the flat tube 20.

According to embodiment 5, the fins 430 protrude from the flat tubes 20, but the reinforcing portions 434 are formed at the upstream end portions of the fins 430, and therefore the fins 430 can be prevented from falling down during manufacturing or transportation. That is, the strength of the fin 430 can be ensured. Further, since the upstream end portions of the fins 430 do not contact the flat tubes 20, the heat transfer area of the upstream end portions, through which the air flows, is smaller than that of the downstream end portions in the fins 430. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 430 can be equalized. Thus, in embodiment 5, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 430 are balanced, and the strength of the fin 430 can be ensured.

Further, since the upstream end portions of the fins 430 do not contact the flat tubes 20, heat transfer on the upstream side of the fins 430 can be suppressed, and uneven frost formation can be suppressed. This can prevent the air passage 31 through which air flows from being blocked by frost. Further, the condensed water attached to the fins 430 flows along the reinforcement portion 434, which is a resin, thereby improving drainage.

(modification example)

Fig. 11 is a cross-sectional view showing a flat tube 20 and a fin 430a according to a modification of embodiment 5. As shown in fig. 11, in the heat exchanger 408a of the modification, the fins 430a protrude further than the flat tubes 20 than in embodiment 5. The reinforcing portion 434a is larger than embodiment 5. Accordingly, the fins 430a protrude significantly more than the flat tubes 20, but the reinforcing portions 434a are formed significantly on the upstream end portions of the fins 430a, and therefore the fins 430a can be prevented from falling down during manufacturing or transportation. Further, since the wide regions of the upstream end portions of the fins 430a do not contact the flat tubes 20, the heat transfer area of the upstream end portions of the fins 430a through which air flows is smaller than that of the downstream end portions. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 430a can be balanced. In this way, the modification can achieve the balance between the amount of heat exchange on the upstream side and the amount of heat exchange on the downstream side of the fin 430a, and ensure the strength of the fin 430 a.

Embodiment 6.

Fig. 12 is a sectional view showing a flat tube 20 and a fin 530 according to embodiment 6. The heat exchanger 508 of embodiment 6 is different from those of embodiments 1 to 5 in that an opening/closing louver 535 is provided in the opening 50. In embodiment 6, the same reference numerals are given to the same portions as those in embodiments 1 to 5, and the description thereof is omitted, and the differences from embodiments 1 to 5 will be mainly described.

As shown in fig. 12, the fin 530 has an opening/closing louver 535 provided in the opening 50 to open and close the opening 50. The upstream end of the flat tube 20 is located at the same position as the upstream end of the fin 530, as in embodiment 1.

According to embodiment 6, the upstream-side end portions of the flat tubes 20 are located at the same positions as the upstream-side end portions of the fins 530. Since the fins 530 do not protrude from the flat tubes 20, the fins 530 can be prevented from falling down during manufacture or transportation. That is, the strength of the fin 530 can be ensured. Further, since the opening 50 for opening and closing the opening/closing louver 535 is formed at the upstream end of the fin 530, the heat transfer area of the upstream end of the fin 530 where the air flows is smaller than that of the downstream end. Therefore, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 530 can be equalized. Thus, in embodiment 6, the heat exchange amount on the upstream side and the heat exchange amount on the downstream side of the fin 530 are balanced, and the strength of the fin 530 can be ensured.

Further, since the opening 50 for opening and closing the opening louver 535 is formed at the upstream end of the fin 530, heat transfer on the upstream side of the fin 530 can be suppressed, and uneven frost formation can be suppressed. This can prevent the air passage 31 through which air flows from being blocked by frost. In addition, the condensed water attached to the fins 530 passes through the openings 50, thereby improving drainage.

Description of the reference numerals

1 … air conditioner; 2 … outdoor unit; 3 … indoor unit; 4 … refrigerant circuit; 5 … refrigerant pipe; a 6 … compressor; 7 … flow channel switching device; 8 … heat exchanger; 9 … outdoor blower; 10 … expansion; 11 … indoor heat exchanger; 12 … indoor blower; 20 … flat tubes; 21 … flow path; 30 … fins; 30a … inclined face; 31 … ventilation; 32 … louver; 33 … slit; 34 … holes; a 40 … header; 50 … opening; 108 … heat exchanger; 130 … fins; a 134 … gap; 208. 208a … heat exchanger; 220. 220a … flat tubes; 230 … fins; 234. 234a … gap; 308 … heat exchanger; 330 … fins; 360 … reinforcement; 408. 408a … heat exchanger; 430. 430a … fins; 434. 434a … reinforcement; 508 … heat exchanger; 530 … fins; 535 … opens and closes the louvres.

Claims

1. A heat exchanger is characterized by comprising:

a plurality of flat tubes through which a refrigerant flows; and

a plurality of fins which are provided between the flat tubes and which transfer heat of the refrigerant flowing through the flat tubes,

an upstream end portion of the flat tube, in which air flows, is located at the same position as the upstream end portion of the fin or protrudes from the upstream end portion of the fin,

openings are formed in the upstream end portions of the flat tubes or the upstream end portions of the fins.

2. The heat exchanger of claim 1,

the opening is a hole formed at the upstream-side end portion of the fin.

3. The heat exchanger according to claim 1 or 2,

the opening is a gap formed between the fin and the flat tube at the upstream-side end portion of the fin.

4. The heat exchanger of claim 3,

the upstream end of the fin is narrower than the downstream end.

5. The heat exchanger according to claim 3 or 4,

the upstream end of the flat tube is narrower than the downstream end.

6. The heat exchanger according to any one of claims 1 to 5,

the fin has an opening/closing louver provided in the opening and opening/closing the opening.

7. A heat exchanger is characterized by comprising:

a plurality of flat tubes through which a refrigerant flows;

a plurality of fins that are provided between the flat tubes and that transfer heat of the refrigerant flowing through the flat tubes, and whose upstream end portions on which air flows protrude than the upstream end portions of the flat tubes; and

and a reinforcing portion provided between portions of the fins which protrude from the flat tubes, the reinforcing portion reinforcing the fins.

8. A heat exchanger is characterized by comprising:

a plurality of flat tubes through which a refrigerant flows; and

a plurality of fins that are provided between the flat tubes and transfer heat of the refrigerant flowing through the flat tubes, upstream-side end portions of the plurality of fins in an air flow direction protruding from the upstream-side end portions of the flat tubes,

an uneven reinforcing portion for reinforcing the fin is formed at the upstream end of the fin.

9. An air conditioner is characterized in that,

a heat exchanger according to any one of claims 1 to 8.