CN107923675B

CN107923675B - Outdoor unit of air conditioner

Info

Publication number: CN107923675B
Application number: CN201680046303.4A
Authority: CN
Inventors: 佐佐木重幸; 塚田福治; 远藤刚; 大木长斗司
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2015-09-08
Filing date: 2016-08-09
Publication date: 2020-07-03
Anticipated expiration: 2036-08-09
Also published as: WO2017042645A1; JP2017053518A; JP6640500B2; CN107923675A

Abstract

An outdoor unit (1) of an air conditioner is provided with heat transfer tubes (21a, 21b) having a flat shape that can effectively reduce ventilation resistance. A heat exchanger (2) of an outdoor unit (1) of an air conditioning device is provided with a plurality of heat transfer tubes (21a, 21b) and a plurality of fins (22) thermally connected to the heat transfer tubes (21a, 21b), wherein, of the plurality of heat transfer tubes (21a, 21b), the flat surfaces of the plurality of heat transfer tubes (21a) arranged above the center of a fan (3) are inclined at a gradient below the fan (3), and the flat surfaces of the plurality of heat transfer tubes (21b) arranged below the center of the fan (3) are inclined at a gradient above the fan (3).

Description

Outdoor unit of air conditioner

Technical Field

The present invention relates to an air conditioner including a heat exchanger used in a refrigeration cycle and including fins and flat heat transfer tubes.

Background

Conventionally, a structure of a heat exchanger using flat tubes has been proposed. The flat tube has a smaller projected area in the air flow direction and a smaller ventilation resistance than a circular tube such as a copper tube widely used in air conditioners, when the circumferential length of the flat tube is the same. Therefore, the power accompanying the blowing of the air for heat exchange is small. In addition, the dead water region downstream of the tube where the heat transfer rate is low is narrow. Therefore, the structure using the flat tube is effective for reducing the power consumption of the air conditioner.

When the heat exchanger is used as an evaporator using an evaporation phenomenon of a fluid inside, moisture condenses on the surfaces of the fins and the flat tubes and forms dew under the condition that the surfaces of the fins are lower than the dew-point temperature of air. This condensed water is expected to be quickly removed by reducing the flow path area of air between the fans, increasing the ventilation resistance, and preventing heat exchange. When the flat tubes of the flat tube heat exchanger are arranged in the horizontal direction perpendicular to the direction of gravity, condensed water stagnates on the flat tubes and tends to grow. As a result, the ventilation resistance increases, and the fan power also increases.

In order to solve this problem, japanese patent application laid-open No. 7-91873 (patent document 1) proposes an invention of a flat tube provided so as to be inclined downward in the direction of gravity with respect to the direction of air flow. By inclining the flat tubes, condensed water droplets can be quickly discharged from between the fins on the upper surfaces of the flat tubes. When the flow of water droplets is formed, the water droplets flowing down the fin surface easily flow downward without stopping around the flat tubes due to the surface tension of the water.

Japanese patent laying-open No. 2012 and 26615 (patent document 2) proposes an invention relating to an outdoor unit structure of a type that sucks ambient air and blows it upward. The air speed of the heat exchanger of the outdoor unit having the up-blowing structure is faster at the upper portion of the fan near the heat exchanger and longer than the fan, and thus the lower portion is smaller. In order to solve the problem and effectively use the heat exchanger, a structure is adopted in which the lower portion of the heat exchanger is inclined at a flat tube angle along the air flow direction, and the flat tube at the upper portion of the heat exchange tube is inclined in the direction blocking the air flow.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 7-91873

Patent document 2: japanese laid-open patent publication No. 2012-26615

Disclosure of Invention

The invention of patent document 1 is a heat exchanger alone, and patent document 1 does not clearly show the relationship with the fan.

The structure of patent document 2 improves the wind speed distribution by locally adding ventilation resistance, but has a problem of increasing the fan power of the heat exchanger in order to block the air flow. The invention of patent document 2 is effective in reducing power consumption under the condition that the degree of imparting compressor input is large due to improvement of wind speed distribution. However, in recent years, evaluation of energy saving under a condition where the air conditioning load is small, which is close to the actual load, has been emphasized, and reduction of the fan power can reduce the entire power consumption in terms of improvement of performance based on such evaluation indexes.

The invention aims to provide an air conditioner which can effectively reduce ventilation resistance and is provided with flat tubes.

In order to achieve the above object, an outdoor unit of an air conditioner according to the present invention includes a casing, a fan that sucks air from outside the casing into the casing and sends the air inside the casing to the outside, and a heat exchanger that exchanges heat with the air sucked from outside the casing, wherein the heat exchanger is disposed along one side surface of two opposite side surfaces of the casing, and the fan is disposed along the other side surface,

the heat exchanger includes a plurality of heat transfer tubes arranged in parallel and having a flat shape, and a plurality of fins thermally connected to the heat transfer tubes,

flat surfaces of the plurality of heat transfer tubes arranged above a center of the fan among the plurality of heat transfer tubes are inclined toward a lower gradient of the fan, flat surfaces of the plurality of heat transfer tubes arranged below the center of the fan are inclined toward an upper gradient of the fan,

flat surfaces of the plurality of heat transfer tubes arranged above the center of the fan and below a position highest in the maximum wind speed position of the fan are inclined upward toward the fan at an upward gradient,

flat surfaces of the plurality of heat transfer tubes arranged below the center of the fan and above a lowest position among maximum wind speed positions of the fan are inclined toward a lower gradient of the fan.

Effects of the invention

In the air conditioner of the present invention, the flat surfaces of the inclined flat tubes are aligned with the flow direction from the upstream side of the flat tubes toward the fan, or the flow direction of a region where the static pressure is low and the maximum wind speed is generated from the upstream side of the flat tubes, so that the ventilation resistance can be effectively reduced. This can reduce the fan power.

Drawings

Fig. 1 is a longitudinal sectional view of an outdoor unit 1 according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view of an outdoor unit 1 according to a second embodiment of the present invention.

Fig. 3 is a vertical sectional view schematically showing a wind speed distribution of the outdoor unit 1 according to the second embodiment of the present invention.

Fig. 4 is a longitudinal sectional view of an outdoor unit 1 according to a third embodiment of the present invention.

Fig. 5 is a longitudinal sectional view of an outdoor unit 1 according to a fourth embodiment of the present invention.

Fig. 6 is a longitudinal sectional view of an outdoor unit 1 according to a fifth embodiment of the present invention.

Fig. 7 is a longitudinal sectional view of an outdoor unit 1 according to a sixth embodiment of the present invention.

Fig. 8 is a longitudinal sectional view of the outdoor unit 1 according to the first reference example of the present invention.

Fig. 9 is a longitudinal sectional view of an outdoor unit 1 according to a second reference example of the present invention.

Fig. 10 is a top view in cross section of an outdoor unit 1 according to a third reference example of the present invention.

Fig. 11 is a top view in cross section of an outdoor unit 1 according to a fourth reference example of the present invention.

Fig. 12 is a vertical sectional view of a conventional cross-blow type outdoor unit 1.

Fig. 13 is a longitudinal sectional view of a conventional up-blowing type outdoor unit.

Fig. 14 is a schematic diagram illustrating a refrigeration cycle as an embodiment of the present invention.

Fig. 15 is a sectional view showing the shape of the

flat tubes

21a and 21 b.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[ example 1]

A first embodiment of the present invention is explained with reference to fig. 1. Fig. 1 is a longitudinal sectional view of an outdoor unit 1 according to a first embodiment of the present invention.

The structure shown in fig. 1 corresponds to an indoor air conditioning apparatus or an outdoor unit of an assembled air conditioner for stores. Inside the casing of the outdoor unit 1, a heat exchanger 2 and a fan 3 are installed at positions facing the front and rear surfaces of the casing. That is, the heat exchanger 2 is disposed along one of two opposing side surfaces of the casing 1a of the outdoor unit 1, and the fan 3 is disposed along the other side surface. The fan 3 is rotationally driven as indicated by reference numeral 31. The outdoor unit 1 is also equipped with a compressor, a four-way valve, an expansion valve, or electric components, not shown, which constitute a refrigeration cycle.

The heat exchanger 2 is provided with short-side aluminum fins 22 formed of thin plates in the direction of gravity. That is, the aluminum fins 22 are arranged so that the longitudinal direction thereof extends along the vertical direction. The aluminum fins 22 are arranged in plural at predetermined intervals, for example, at intervals of 1mm to 2mm in a direction perpendicular to the paper surface of fig. 1. The flat heat transfer tubes (hereinafter, referred to as flat tubes) 21a and 21b are inserted horizontally from the lateral direction of the aluminum fins 22 between the adjacent

flat tubes

21a and 21b arranged in the vertical direction, with a predetermined space therebetween. The adjacent

flat tubes

21a, 21b are spaced apart from each other by, for example, 10mm to 25 mm.

Most of the

flat tubes

21a and 21b are formed by extrusion of aluminum. A plurality of flow channels having a minute width (about 1 mm) are formed in the

flat tubes

21a and 21b, and a fluorocarbon refrigerant such as 410A, R32 flows through the flow channels.

The shape of the

flat tubes

21a and 21b will be described with reference to fig. 15. Fig. 15 is a sectional view showing the shape of the

flat tubes

21a and 21 b. The cross section shown in fig. 15 is a cross section perpendicular to the flow direction of the refrigerant. The flat tube has a plurality of flow channels 210 formed therein.

As shown in fig. 15, the

flat tubes

21a and 21b have a flat cross section. The cross section has a major axis 21L along the longitudinal direction and a minor axis 21S along a direction perpendicular to the longitudinal direction. Curved surfaces 21C having a large curvature are formed at both ends of the long axis (longitudinal direction) 21L. Flat surfaces 21P are formed at both ends of the short shaft 21S. In the present embodiment, the flat surface 21P is constituted by a flat surface. That is, the

flat tubes

21a and 21b of the present embodiment have a cross section formed by connecting both end portions of two flat surfaces 21P provided in parallel by curved surfaces 21C. The flat surface 21P is a curved surface having a curvature larger than that of the curved surface 21C, but in the present embodiment, the flat surface 21P is a flat surface in order to reduce the ventilation resistance and to narrow the space in which the

flat tubes

21a and 21b are disposed.

As a heat transfer performance, heat is transferred between the inner surfaces of the flow paths of the

flat tubes

21a and 21b and the freon refrigerant by a phase change of evaporation and condensation. The heat transfer rate due to this phase change is generally large, and is several thousand W/(m)²K) or so. On the other hand, the forced convection heat transfer rate between the surface of the fin 22 and the air is relatively small, and is several tens of W/(m) due to physical values such as the density of the air and the condition of relatively low wind speed²K) or so. In order to improve the heat transfer performance by the heat exchanger alone, it is desirable to make the thermal resistances of the refrigerant side and the air side as close as possible. Therefore, the heat transfer surface of the fins 22 is enlarged to reduce the thermal resistance between the fins 22 and the air. Therefore, the fins 22 are provided so as to surround the

flat tubes

21a and 21 b. The area magnification of the fins 22 is set to about several times to several tens times the refrigerant flow path area.

The aluminum fin 22 of the heat exchanger 2 in the assembly step is formed by cutting an aluminum thin plate, the surface of which is coated with a brazing material in advance, into a short side shape by press working, and performing cutting for inserting the flat tube in accordance with the cutting. In the assembly step, the aluminum

flat tubes

21a and 21b are inserted from the lateral direction, and headers are attached to the end portions of the

flat tubes

21a and 21b to be temporarily assembled. Thereafter, the brazing material is melted by giving a temperature change suitable for the brazing material in the furnace, and the fins 22 and the

flat tubes

21a and 21b are mechanically and thermally joined to each other, thereby completing the heat exchanger 2 having airtightness.

The header is a tubular member having holes, and the

flat tubes

21a and 21b are inserted into the holes and brazed. The header is a member that divides the refrigerant into a plurality of

flat tubes

21a, 21b or merges the refrigerant from the plurality of

flat tubes

21a, 21 b. The headers are provided at both end portions of the

flat tubes

21a, 21b, as shown by reference numerals 81 to 84 in fig. 10, for example.

Next, the operation of the heat pump type air conditioner according to the present invention will be described with reference to fig. 14. Fig. 14 is a schematic diagram illustrating a refrigeration cycle as an embodiment of the present invention.

First, the structure of the refrigeration cycle will be described.

The refrigeration cycle of the air conditioner is roughly composed of a compressor 8, a four-way valve 9, an expansion valve 10, an outdoor heat exchanger 110 in the outdoor unit 11, and an indoor heat exchanger 120 in the indoor unit 12. Further, a fan 312 and a fan 311 are provided in the vicinity of the indoor heat exchanger 120 and the outdoor heat exchanger 110, respectively.

Next, an operation of the air conditioner will be described.

Arrows 01 indicate the flow direction of the refrigerant in the cooling operation.

In the cooling operation, the outdoor heat exchanger 110 functions as a condenser, and the indoor heat exchanger 120 functions as an evaporator. The refrigerant that has become high-temperature and high-pressure by the operation of the compressor 8 passes through the four-way valve 9, and the flow direction thereof is set to the direction in which the refrigerant flows toward the outdoor unit 11 first. The refrigerant flowing into the outdoor unit 11 flows through the flow passages in the plurality of

flat tubes

21a and 21b of the outdoor heat exchanger 110 in the outdoor unit 11. Then, ambient air is sucked in by the operation of the fan 311, and heat is radiated to low-temperature air flowing between the fins 22 of the outdoor heat exchanger 110.

The refrigerant is in a high-temperature, high-pressure superheated gas state (a gas refrigerant having a temperature higher than the saturation temperature) at the inlet portion of the heat exchanger 110, and gradually liquefies while releasing heat to the air as it flows through the flow passages in the

flat tubes

21a, 21 b. In the vicinity of the outlet of the heat exchanger 110, the refrigerant is in a supercooled state (a liquid refrigerant having a temperature lower than the saturation temperature). In this case, the sensible heat alone moves between the surface of the fin 22 and the air.

The refrigerant flowing out of the outdoor heat exchanger 110 is then reduced in pressure by being throttled in the passage by an electronic expansion valve, a temperature-sensitive expansion valve, or a capillary tube (capillary tube), which is shown as the expansion valve 10. The decompressed refrigerant is converted into a low-temperature and low-pressure refrigerant by isenthalpic expansion.

After that, the refrigerant flows through the heat transfer pipes of the indoor heat exchanger 120 in the indoor unit 12 serving as an evaporator. The refrigerant in the heat transfer pipe absorbs heat from the high-temperature ambient air sucked by the operation of the fan 312, and then flows while being gasified. At the outlet portion of the heat exchanger 120, the refrigerant is in a superheated state (state in which the temperature is higher than the saturation temperature), and returns to the compressor 8 again.

By repeating the series of cycles, the cooling operation can be performed. In fig. 12, the

fans

311 and 312 of the outdoor unit 11 and the indoor unit 12 are illustrated in a spiral shape. The

fans

311, 312 may be other fan forms.

Next, prior to describing the features of the present invention, a conventional configuration will be described. Fig. 12 is a vertical sectional view of a conventional cross-blow type outdoor unit 1.

Flat tubes

21a and 21b are horizontally provided in the heat exchanger 22. When the fan 3 is operated, air around the casing 1a is sucked into the casing 1 a. The air sucked into the case 1a turns the upward flow 4a and the downward flow 4b horizontally in the heat exchanger 2, and therefore the ventilation resistance is large due to the bending. When the heat exchanger 2 is used as an evaporator, water droplets are likely to accumulate on the upper surfaces of the

flat tubes

21a and 21b, and there is a problem that the fan power increases.

Therefore, in the present invention shown in fig. 1, the

flat tubes

21a and 21b of the heat exchanger 2 are inclined toward the fan 3. Specifically, the flat tubes 21a of the heat exchanger 2a above the center position 3a of the fan 3 are provided with a downward gradient in the ventilation direction (fan 3). The flat tubes 21b of the heat exchanger 2b below the center position 3a of the fan 3 are inclined upward in the ventilation direction (fan 3). By providing the

flat tubes

21a and 21b with such an inclination angle, the

flows

4a and 4b of air from upstream of the casing 1a toward the fan 3 are not obstructed. Further, the heat exchanger 2 with low ventilation resistance can be obtained. As a result, the air conditioner having low power of the fan 3 and low power consumption as a whole can be configured.

The following describes the heating operation.

In the heating operation, the setting of the flow passage of the four-way valve 9 shown in fig. 12 is changed, whereby the refrigerant discharged from the compressor 8 flows in the direction indicated by the arrow 02 in the reverse direction to the cooling operation.

In the heating operation, the heat exchanger 110 of the outdoor unit 11 functions as an evaporator. In this case, the fin surface is lower than the dew point temperature of air, and therefore, the latent heat transfer phenomenon is involved. The moisture in the air cooled between the fins 22 condenses to form water droplets and adheres to the fin surfaces. The water droplets join with other water droplets, but flow downward in the gravity direction due to their own weight. At this time, the water droplets collide with the

flat tubes

21a, 21b inserted in the horizontal direction. In the present embodiment, since the

flat tubes

21a and 21b are inclined in the direction of gravity, water droplets colliding with the

flat tubes

21a and 21b can move downward while receiving the action of gravity according to the inclination angle.

As shown in fig. 1, the

flat tubes

21a and 21b are inclined toward the fan 3, whereby the condensate on the upper surfaces of the flat tubes can be guided downward in the direction of gravity. Specifically, in the upper heat exchanger 2a, since the flat tubes 21a are inclined downward in the ventilation direction, the condensed water collects from the fin front edge 221a side toward the fin rear edge 222a, and flows down toward the fin rear edge 222a as indicated by an arrow 5 a. In the lower heat exchanger 2b, since the flat tubes 21b are inclined upward in the ventilation direction, the condensate collects from the fin rear edge 222b side toward the front of the heat exchanger 2b (the fin front edge 221b side), and flows down on the fin front edge 221b side as indicated by an arrow 5 b. This enables the condensed water between the fins 22 to be quickly drained. The condensed water finally accumulated in the lower portion of the tank 1a is discharged to the outside through the drain port 6 at the lowermost portion.

In this way, since the condensed water in the case where the evaporator functions can be quickly drained, the heat exchanger has high water removal performance. As a result, even when the heat exchanger functions as both the condenser and the evaporator, the increase in the fan power can be suppressed.

[ example two ]

Next, a second embodiment of the present invention will be described with reference to fig. 2 and 3. The same components as those in the above-described embodiment are denoted by the same reference numerals as those in the above-described embodiment, and only the portions different from the above-described embodiment will be described.

Fig. 2 and 3 are different from fig. 1 in that the

flat tubes

21a and 21b are inclined toward the approximate maximum wind speed position 32 in the vicinity of the outer peripheral portion of the fan 3.

The flat tubes 21a of the heat exchanger 2a above the center position 3a of the fan 3 are divided into flat tube groups 21a1 and flat tube groups 21a 2. The flat tube group 21a1 is a flat tube group disposed above the maximum wind speed position 32. The flat tube group 21a2 is disposed below the maximum wind speed position 32 and above the center position 3 a. In the flat tube group 21a1, the flat tubes 21a are provided with a downward slope toward the ventilation direction (fan 3). In the flat tubes 21a2, the flat tubes 21a are provided with upward slopes toward the ventilation direction (fan 3).

The flat tubes 21B of the heat exchanger 2B below the center position 3a of the fan 3 are divided into flat tube groups 21B1 and flat tube groups 21B 2. The flat tube group 21B1 is a flat tube group disposed below the maximum wind speed position 32. The flat tube group 21B2 is a flat tube group disposed above the maximum wind speed position 32 and below the center position 3 a. In the flat tube group 21B1, the flat tubes 21B are provided with an upward slope toward the ventilation direction (fan 3). In the flat tube group 21a2, the flat tubes 21b are provided with a downward slope toward the ventilation direction (fan 3).

Since the

flat tubes

21a and 21b have such an inclination angle, the air flows 4a1, 4a2, 4b2, and 4b1 from upstream of the casing 1a to the fan 3 are not obstructed. Further, the heat exchanger 2 with low ventilation resistance can be obtained. As a result, the air conditioner having low power of the fan 3 and low power consumption as a whole can be configured.

Axial fans such as the propeller fan shown in fig. 3 generally generate a maximum wind speed with a peripheral speed greater than that at a position 32 near the outer peripheral portion. Therefore, the static pressure in the vicinity of this maximum wind speed location 32 is low, and upstream air is sucked thereinto. Therefore, when the

flat tubes

21a and 21b are inclined to the maximum wind speed position 32, the fan power can be reduced without obstructing the air flow.

The maximum wind speed position 32 is located on the outer peripheral side of the central position 3a of the fan 3 and the central position 3b of the outer diameter position (outer peripheral position) of the fan 3. The maximum wind speed position 32 is a circle centered on the center position 3a of the fan 3. On this circumference, the highest position is referred to as an upper maximum wind speed position 32, and the lowest position is referred to as a lower maximum wind speed position 32.

The structure of the present embodiment is more effective when the heat exchanger 2 is close to the fan 3 and the casing 1 is made thin, particularly as compared with the structure shown in fig. 1. The flat tube groups 21a1, 21a2, 21B2, 21B1 may have the same inclination angle in the respective groups, but may be a structure in which the inclination angle is further subdivided and changed.

[ third example ]

Next, a third embodiment of the present invention will be described with reference to fig. 4. The same components as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and only the portions different from those in the above embodiment will be described.

The present embodiment is configured such that the number of rows is increased in the ventilation direction in the heat exchanger 2 of the first embodiment shown in fig. 1. The heat exchanger 2 includes an upper heat exchanger 2a and a lower heat exchanger 2 b. The positional relationship between the upper heat exchanger 2a and the lower heat exchanger 2b with respect to the vertical direction (gravitational direction) of the fan 3 is the same as that of the first embodiment. Specifically, the heat exchanger 2 includes, as the upper heat exchanger 2a, a first row heat exchanger 2a1 arranged on the windward side and a second row heat exchanger 2a2 arranged on the windward side. The heat exchanger 2 includes, as the lower heat exchanger 2b, a first row heat exchanger 2b1 arranged on the windward side and a second row heat exchanger 2b2 arranged on the windward side. The upper heat exchanger 2a and the lower heat exchanger 2b are each provided with two rows of heat exchangers.

The first heat exchanger row 2a1 and the second heat exchanger row 2a2 that constitute the upper heat exchanger 2a each include flat tubes 21a that are inclined in the same manner as the flat tubes 21a of the upper heat exchanger 2a of the first embodiment. The first row heat exchanger 2b1 and the second row heat exchanger 2b2 that constitute the lower heat exchanger 2b each include flat tubes 21b that are inclined in the same manner as the flat tubes 21b of the lower heat exchanger 2b of the first embodiment.

With this configuration, the heat exchanger 2 having a smaller ventilation resistance can be configured while ensuring a larger heat transfer area than in the first and second embodiments in the fins 22. In addition, even in the water removing property of the condensed water, a high effect can be obtained.

[ example four ]

Next, a fourth embodiment of the present invention will be described with reference to fig. 5. The same components as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and only the portions different from those in the above embodiment will be described.

The outdoor unit 1 of fig. 5 includes two rows of heat exchangers 2a1, 2a2, 2b1, and 2b2, as in fig. 4. The heat exchanger 2 includes an upper heat exchanger 2a and a lower heat exchanger 2b, as in the third embodiment. The positional relationship between the upper heat exchanger 2a and the lower heat exchanger 2b with respect to the vertical direction (gravitational direction) of the fan 3 is the same as that in the first and third embodiments.

In the present embodiment, the first row upper heat exchanger 2a1 and the first row lower heat exchanger 2b1 have the

flat tubes

21a, 21b inclined as in the third embodiment. The second upper heat exchanger 2a2 and the second lower heat exchanger 2b2 are different from the third embodiment. That is, the flat tubes 21a disposed in the second row upper heat exchanger 2a2 and the flat tubes 21b disposed in the second row lower heat exchanger 2b2 have flat surfaces 21P (long axes 21L) substantially horizontal.

When the air flows from the first row of

flat tubes

21a, 21b can be diverted substantially in the horizontal direction, even if the second row of

flat tubes

21a, 21b is disposed in the horizontal direction, the ventilation resistance is not increased. In the case where the heat exchanger 2 functions as an evaporator, when most of the moisture in the air is condensed in the first row above the wind, it is not necessary to incline the second row of

flat tubes

21a and 21b below the wind.

[ example five ]

Next, a fifth embodiment of the present invention will be described with reference to fig. 6. The same components as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and only the portions different from those in the above embodiment will be described.

In the outdoor unit 1 of fig. 6, the upper heat exchanger 2a and the lower heat exchanger 2b of the second embodiment shown in fig. 2 are applied to the windward first-row upper heat exchanger 2a1 and the lower heat exchanger 2b1 in the fourth embodiment shown in fig. 5. Accordingly, the first row of

flat tubes

21a, 21b is inclined to the maximum wind speed position 32 of the fan 3 in the windy direction. In the present embodiment, in addition to the effects of the fourth embodiment, the effects of the second embodiment can be obtained, which is advantageous in the case of the thin case 1 a. In the embodiment shown in fig. 4 to 6, the

flat tubes

21a and 21b of the second row heat exchanger in the windward direction may be inclined, but may be horizontal. The pressure loss is determined by the pressure loss in the relationship between the gaps between the

flat tubes

21a and 21b and the gaps between the fins 22.

In the embodiment of fig. 1 to 6, the

flat tubes

21a and 21b are disposed on the rear edge side of the fins 22 with respect to the heat exchanger 2. Under the low-temperature frosting condition, the

flat tubes

21a and 21b through which the low-temperature refrigerant flows are separated from the front edges of the fins 22, so that the temperature of the front edges of the fins 22 is increased, and the frosting is difficult to occur.

[ sixth example ]

Next, a sixth embodiment of the present invention will be described with reference to fig. 7. The same components as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and only the portions different from those in the above embodiment will be described.

The outdoor unit 1 of fig. 7 includes an upper heat exchanger 2a and a lower heat exchanger 2b, as in the first embodiment shown in fig. 1. The positional relationship of the upper heat exchanger 2a and the lower heat exchanger 2b with respect to the vertical direction (the direction of gravity) of the fan 3 is the same as that of the first embodiment. The

flat tubes

21a and 21b are inclined toward the center of the fan 3, as in the first embodiment. However, unlike the invention of fig. 1, the flat tubes 21a of the upper heat exchanger 2a are arranged to be offset windward. That is, the plurality of flat tubes 21a disposed above the center of the fan 3 are attached to the side surface of the case 1a on which the heat exchanger 2 is disposed, with respect to the fan 3. The plurality of flat tubes 21b disposed below the center of the fan 3 are attached to the fan 3 so as to be offset to the side of the case 1a opposite to the side on which the heat exchanger 2 is disposed.

With this configuration, as indicated by reference numeral 5aa, the water passage on the fin surface of the upper heat exchanger 2a can be secured wide. Further, the heat exchanger 2 having high water removal performance can be configured. In this case, in the upper heat exchanger 2a, the flat tubes 21aa through which the low-temperature refrigerant flows are not separated from the front edges of the fins 22, and the temperature of the front edges of the fins 22 is increased, thereby obtaining an effect that frost is less likely to form. Therefore, it is advantageous when there is a margin in frost resistance as compared with the structure of fig. 1.

Next, the structure of the

flat tubes

21a and 21b suitable for the up-flow type outdoor unit will be described as a reference example.

First, a conventional up-blowing type outdoor unit will be described with reference to fig. 13.

The outdoor units of the up-blowing structure are generally arranged on the roof of a building in an equal arrangement. In this case, the upward blowing structure is adopted so that the air blown from 1 outdoor unit is not sucked into the heat exchangers of the other outdoor units by the wind direction on the roof of the building. The heat exchanger provided in the outdoor unit casing 1a in the direction of gravity is provided with horizontal

flat tubes

21a and 21b inserted in the horizontal direction.

In the conventional example of fig. 13, the flat surfaces (major axes) of the

flat tubes

21a and 21b are arranged in the horizontal direction. Therefore, the upper heat exchanger 2a close to the fan 3 sucks in the air around the casing 1a from substantially the horizontal direction. The lower heat exchanger 2b sucks air below the tank 1a from substantially the horizontal direction. The air having passed through the

heat exchangers

2a and 2b is sucked up by the operation of the fan 3 in a direction changed upward. Therefore, the direction of the air flow is largely changed between the upstream side and the downstream side of the

heat exchangers

2a and 2b, and thus the draft resistance by the amount of the curvature is added.

< first reference example >

In the present reference example, the flat tubes 21a of the upper portion 2a of the heat exchanger 2 are set to decrease in inclination angle toward the fan 3. That is, the inclination angle of the flat tubes 21a with respect to the horizontal direction is reduced. On the other hand, the inclination angle of the flat tubes 21b of the lower portion 2b of the heat exchanger 2 is set to be large. That is, the inclination angle of the flat tubes 21b with respect to the horizontal direction is reduced.

This allows a large amount of air 4a to be sucked from a portion of the upper portion 2a where the wind speed is high. On the other hand, the air 4b can be sucked into the lower portion 2b at a low wind speed with a reduced ventilation resistance. As a result, the fan power can be reduced. Further, since the

flat tubes

21a and 21b are inclined, the condensed water accumulated on the upper surfaces of the flat tubes between the fins can be quickly discharged.

< second reference example >

In the present reference example, the heat exchanger 2 of the first reference example is divided into an upper heat exchanger 2a and a lower heat exchanger 2 b. With this configuration, the jig for manufacturing can be manufactured separately, and therefore, the manufacturing is easy. The flat tubes 21a of the upper heat exchanger 2a and the flat tubes 21b of the lower heat exchanger 2b are configured in the same manner as in the first reference example. That is, the inclination of the flat tubes 21a is small, and the inclination of the flat tubes 21b is large.

< third reference example >

Fig. 10 is a cross-sectional view of an outdoor unit 1 according to a third reference example of the present invention.

The outdoor unit 1 of the present reference example includes a left heat exchanger 121, a back-face side heat exchanger 122, and a right heat exchanger 123. The rear-face side heat exchanger 122 includes

headers

82 and 83 at its left and right ends. The header 81 and the header 82 are provided in the left heat exchanger 121. The right heat exchanger 123 includes a header 83 and a header 84. Each header may have a hole so as to be inserted into the inclined flat tube 21. With this configuration, the front surface area can be secured to a large extent by the flat heat exchangers 121 to 123 using the inclined flat tubes 21.

< fourth reference example >

Fig. 11 is a cross-sectional view of an outdoor unit 1 according to a fourth reference example of the present invention.

The flat tube portions 21 are bent without providing fins in the bent portions, instead of the

headers

82 and 83 in fig. 10. With this configuration, the heat exchanger 2 having the bent portions 21 can be relatively easily manufactured using the inclined flat tubes 21.

In the air conditioning apparatus according to each embodiment of the present invention, the flat surfaces of the inclined flat tubes are aligned with the flow direction from the ambient air to the fan or the flow direction to the area where the static pressure is low and the maximum wind speed is generated. That is, the flat tubes of the embodiments have flat surfaces inclined so as to be along the flow direction of air toward the inlet portion of the heat exchanger attached to the air conditioner case. This reduces the ventilation resistance and reduces the fan power (blowing power). Further, the inclination of the flat tubes provides excellent water removal performance on the upper surfaces of the flat tubes. Therefore, in the case where the heat exchanger is used as an evaporator, the condensed water adhering to the upper surfaces of the flat tubes can be quickly drained. As a result, the drainage of the condensed water from the fin surface can be improved. By these effects, the power consumption of the air conditioner including the heat exchanger including the fins and the flat heat transfer tubes can be reduced.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments are described in detail for the purpose of easy understanding of the present invention, and are not necessarily limited to the configurations including all of the descriptions. In addition, a part of the structure of one embodiment may be replaced with the structure of another embodiment, and the structure of another embodiment may be added to the structure of one embodiment.

Description of the symbols

1-outdoor unit, 2-heat exchanger, 2 a-upper heat exchanger, 2a1, 2a 2-upper heat exchanger, 2 b-lower heat exchanger, 2b1, 2b 2-lower heat exchanger, 3-fan, 3 a-center position of fan 3, 4-air stream, 4a1, 4a 2-upper upstream air stream, 4b, 4B1, 4B 2-air flow upstream of the lower portion, 5-flow of condensed water, 6-drain, 7-compressor, 8-header, 9-quad valve, 10-expansion valve, 11-outdoor unit, 12-indoor unit, 21-flat tube, 21 a-flat tube, 21B-flat tube, 21a1, 21a 2-flat tube group, 21B1, 21B 2-flat tube group, 22-fin, 31-rotation of fan, 32-maximum wind speed position, 110-outdoor heat exchanger, 120-indoor heat exchanger, 221-fin leading edge, 222-fin trailing edge.

Claims

1. An outdoor unit of an air conditioner including a casing, a fan for sucking air from outside the casing to inside the casing and sending the air inside the casing to outside, and a heat exchanger for exchanging heat with the air sucked from outside the casing, wherein the heat exchanger is disposed along one side surface of two opposite side surfaces of the casing, and the fan is disposed along the other side surface,

2. The outdoor unit of an air conditioner according to claim 1,

comprises a first heat exchanger and a second heat exchanger divided in the air flow direction,

at least the first row of heat exchangers has the heat transfer tubes with flat surfaces inclined upward and downward toward the fan.

3. The outdoor unit of an air conditioner according to claim 1,

the heat transfer tubes whose flat surfaces are inclined upward and downward toward the fan constitute the first row of heat exchangers,

the second row heat exchanger is arranged such that the flat surfaces of the flat heat transfer tubes extend in the horizontal direction.

4. The outdoor unit of an air conditioner according to claim 1,

the plurality of heat transfer tubes inclined at a downward slope toward the fan and the plurality of heat transfer tubes inclined at an upward slope toward the fan are attached to the fins so as to be offset toward the side opposite to the one side surface side of the case.

5. The outdoor unit of an air conditioner according to claim 1,

a plurality of heat transfer tubes arranged above the center of the fan are attached to the fins so as to be offset toward the one side surface of the case,

the plurality of heat transfer tubes disposed below the center of the fan are attached to the fins so as to be offset to the side of the case opposite to the one-side surface.