DESCRIPTION

TITLE OF INVENTION

Cooling Device and Air Conditioner Including the Same

TECHNICAL FIELD

The present invention relates to a cooling device for cooling control parts of an air conditioner, and also relates to an air conditioner equipped with the cooling device.

BACKGROUND ART

Conventionally, in air conditioners having a compressor, an outdoor heat exchanger, a pressure reduction unit, an indoor heat exchanger, and pipes for connecting these members so that a refrigerant flows therethrough, it is practiced that control parts such as a control board are housed in a control box that can provide protection from, for example, dust, water and the like.

For housing of the control parts in the control box, cooling of the control parts needs to be considered so as to ensure stable operation of the control parts. In an air conditioner described in PTL1 as an example, a control part (circuit board including heat-generating elements) is housed in a control box (electrical part box), and a cooling member (heat sink) for cooling air in the electrical part box is provided in the electrical part box.

More specifically, the air conditioner described in PTL1 uses natural convection to do indirect cooling of heat-generating element with a heat sink. In the electrical part box, the heat sink is positioned above the heat-generating element and apart from the heat-generating element, and air cooled by the heat sink is let down toward the heat-generating element. Meanwhile, air heated by the heat-generating element goes up toward the heat sink. As a result of this, natural convection is generated in the electrical part box, and the heat-generating element is cooled indirectly by the heat sink located above the heat-generating element.

CITATION LIST Patent Literature
PTL1: JP 2010-2120 A

SUMMARY OF INVENTION

Technical Problem

However, in the case of the air conditioner described in PTL1, since the heat sink is positioned above the heat-generating element, there may occur condensed water on the surface of the heat sink depending on environments of use, so that dropping of the condensed water may cause the heat-generating element to be wetted, leading to a possibility of short-circuiting of the heat-generating element. Thus, such an air conditioner like this lacks in reliability.

Accordingly, an object of the present invention is to provide an air conditioner in which control parts of the air conditioner are housed in a control box so as to be protected and cooled while wetting of the control parts by condensed water is suppressed so that the air conditioner is high in reliability.

Solution to Problem

In order to achieve the above object, the present invention has the following constitutions.

According to a first aspect of the present invention, there is provided a cooling device for cooling a control part housed in a control box of an air conditioner, the air conditioner having a compressor, an outdoor heat exchanger, a pressure reduction unit, an indoor heat exchanger, and pipes for connecting these members so that a refrigerant flows therethrough, the cooling device comprising a cooling unit which is placed at a position within the control box below the control part and apart from the control part or at a position within the control box horizontal relative to the control part and which serves for cooling air inside the control box through heat exchange with the refrigerant.

According to a second aspect of the present invention, there is provided the cooling device of the first aspect, wherein the cooling unit comprises: an intra-control box pipe placed within the control box and serving for the refrigerant to flow therethrough; and a fin structure provided with a plurality of fins and attached on the intra-control box pipe.

According to a third aspect of the present invention, there is provided the cooling device of the second aspect, wherein the intra-control box pipe of the cooling unit is part of a pipe that connects the pressure reduction unit and the indoor heat exchanger to each other.

According to a fourth aspect of the present invention, there is provided the cooling device of any one of the first to third aspect, further comprising a dew receiving pan serving for receiving condensed water and placed below the cooling unit.

According to a fifth aspect of the present invention, there is provided the cooling device of any one of the first to fourth aspect, further comprising a heat insulating material for heat-insulating an internal space of the control box.

According to a sixth aspect of the present invention, there is provided the cooling device of the fifth aspect, wherein the heat insulating material is a vacuum heat insulating material.

According to a seventh aspect of the present invention, there is provided an air conditioner including the cooling device as defined in any one of the first to sixth aspect.

Advantageous Effects of Invention

According to the present invention, the cooling unit for cooling air inside the control box is placed at a position within the control box below the control part and apart from the control part or at a position within the control box horizontal relative to the control part. As a result of this, there can be realized an air conditioner in which control parts are kept from temperature rises while wetting of the control parts by condensed water generated on the surface of the cooling unit is suppressed so that the air conditioner is high in reliability.

BRIEF DESCRIPTION OF DRAWINGS

The above aspects and features of the present invention will become more apparent from the following description of preferred embodiments thereof with reference to the accompanying drawings, and wherein:

Fig. 1 is a view schematically showing a structure of an air conditioner according to an embodiment of the invention;

Fig. 2 is a view schematically showing an inside of the control box shown in Fig. 1;

Fig. 3 is a perspective view of a cooling unit shown in Fig. 1; and

Fig. 4 is a view schematically showing an inside of a control box in an air conditioner according to another embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

In a first aspect of the present invention, there is provided a cooling device for cooling a control part accommodated in a control box of an air conditioner having a compressor, an outdoor heat exchanger, a pressure reduction unit, an indoor heat exchanger, and pipes for connecting these members so that a refrigerant flows therethrough, wherein the cooling device comprises a cooling unit which is placed at a position within the control box below the control part and apart from the control part, or at a position within the control box horizontal relative to the control part, so that air in the control box is cooled by heat exchange with the refrigerant.

With this constitution, the cooling unit for cooling the air inside the control box is placed at a position
within the control box below the control part and apart from the control part, or at a position within the control box horizontal relative to the control part. As a result of this, wetting of the control parts by condensed water generated on the surface of the cooling unit is suppressed.

In a second aspect of the invention, in the cooling device, the cooling unit further comprises: an intra-control box pipe placed within the control box and serving for the refrigerant to flow therethrough; and a fin structure provided with a plurality of fins and attached on the intra-control box pipe. As a result of this, heat exchange between air inside the control box and the refrigerant flowing through the intra-control box pipe is performed with high efficiency.

In a third aspect of the invention, in the cooling device, the intra-control box pipe of the cooling unit is part of a pipe that connects the pressure reduction unit and the indoor heat exchanger to each other. With effective use of the pipe for connection of the pressure reduction unit and the indoor heat exchanger, it is no longer necessary to provide any additional pipe only for cooling of the air inside the control box.
In a fourth aspect of the invention, the cooling device further comprises a dew receiving pan serving for receiving condensed water and placed below the cooling unit. As a result of this, component members of the air conditioner located below the cooling unit can be prevented from being wetted by condensed water generated on the surface of the cooling unit.

In a fifth aspect of the invention, the cooling device further comprises a heat insulating material for heat-insulating an internal space of the control box. As a result of this, transfer of heat from outside to inside of the control box is suppressed. As a result, the cooling effect for the control part by the cooling unit is improved in comparison to cases in which the heat insulating material is not present.

In a sixth aspect of the present invention, in the cooling device, the heat insulating material is a vacuum heat insulating material. By the vacuum heat insulating material, transfer of heat from outside to inside of the control box is further suppressed in comparison to heat insulating materials. As a result, the cooling effect for the control part by the cooling unit is further improved.

In a seventh aspect of the present invention, there is provided an air conditioner including the cooling device of any one of the first to sixth aspects of the invention. As a result of this, there can be realized an air conditioner having high reliability.

Fig. 1 is a view schematically showing the structure of an air conditioner according to the present invention. Fig. 2 is a view outlining internal structure of a control box according to an embodiment of the invention.

As shown in Fig. 1, the air conditioner 10 has a compressor 12, an outdoor heat exchanger 14, a pressure reduction unit 16, an indoor heat exchanger 18 and refrigerant pipes 20 - 26 for connecting these members. Adoptable as the pressure reduction unit 16 is an expansion valve or a capillary tube made of copper. It is noted that the air conditioner 10 is divided into an outdoor unit in which the compressor 12, the outdoor heat exchanger 14 and the pressure reduction unit 16 are housed, and an indoor unit in which the indoor heat exchanger 18 is housed.

The air conditioner 10 is so constructed as to fulfill a refrigerating cycle in which a refrigerant flows, via the refrigerant pipes 20 - 26, from the compressor 12 successively through the outdoor heat exchanger 14, the pressure reduction unit 16 and the indoor heat exchanger 18 to return to the compressor 12 again.
In the refrigerating cycle, the refrigerant, after compressed by the compressor 12, flows in a vapor-phase state through the refrigerant pipe 20 toward the outdoor heat exchanger 14. Then, the refrigerant, deprived of heat through heat exchange with outdoor air via the outdoor heat exchanger 14, goes to a liquid-phase state and flows through the refrigerant pipe 22 toward the pressure reduction unit 16.

Subsequently, the refrigerant, while inflated by the pressure reduction unit 16 so as to be decreased in pressure, flows through the refrigerant pipe 24 toward the indoor heat exchanger 18. Then, the refrigerant, depriving the indoor air of heat via the indoor heat exchanger 18, goes to a vapor-phase state and flows through the refrigerant pipe 26 toward the compressor 12.

The air conditioner 10 also includes a control board (i.e. control part) 30 for controlling the refrigerating cycle, and a control box 32 for protecting the control board 30. It is noted that the control box 32 is provided in the outdoor unit.

Herein, the term 'control part' refers to a component part for use in control of the air conditioner 10, exemplified by electronic components that control output of the compressor 12 or throttling quantity of the expansion valve as the pressure reduction unit 16, where the control part is a component part that partly or wholly generate heat so as to need cooling, without being limited to a control board on which a plurality of electronic components are mounted thereon.

The control board 30 is housed in the control box 32 so as to be protected from powder dust, water and the like. Therefore, the control box 32 is made up so as to be prevented from invasion of powder dust or water into its inside. For example, a hole for passage of a cable (not shown) that extends from the control board 30 to outside of the control box 32 is sealed. Preferably in terms of maintainability, the control box 32 is made up of a main body opened in its top face, and a cover for covering the top face of the main body, and desirably, a seal is provided between the main body and the cover. For such a seal, sponge-like resin material such as EPT sheet may be used.

The control board 30 is housed in the control box 32 and thus needs cooling. Therefore, a cooling unit 34 is provided in the control box 32.

The cooling unit 34, which is so designed as to cool air inside the control box 32 through heat exchange with the refrigerant in the refrigerating cycle, is made up of a refrigerant pipe 24, and a fin structure 36 fitted to the refrigerant pipe 24, as shown in Fig. 2.

In more detail, part of the refrigerant pipe 24 runs through within the control box 32 as shown in Fig. 1, and the fin structure 36 having a plurality of plate-shaped fins 36a is fitted at a portion of the refrigerant pipe 24 within the control box 32 as shown in Fig. 2. The cooling unit 34 cools the air inside the control box 32 by heat exchange between the air inside the control box 32 and the refrigerant flowing through within the refrigerant pipe 24. By such a cooling unit 34, the control board 30 is cooled via air.

Preferably, the refrigerant pipe forming part of the cooling unit 34 is provided by the refrigerant pipe 24 that connects the pressure reduction unit 16 and the indoor heat exchanger 18 to each other. With effective use of the refrigerant pipe 24, it is no longer necessary to provide any additional pipe for passage of the refrigerant through within the control box 32 only for the cooling of the air inside the control box.

Further, the refrigerant pipe 24, through which the refrigerant reduced in pressure by the pressure reduction unit 16 flows, is smaller in pressure or vibrations involved than the other refrigerant pipes 20, 22, 26 shown in Fig. 1. Therefore, setting the refrigerant pipe 24 within the control box 32 makes it possible to suppress vibrations, than in cases where the other refrigerant pipes 20, 22, 26 are provided. As a consequence of this, it becomes possible to thin the thickness of the pipe provided in the control box 32, producing subordinate merits that materials to be used can be lessened and the cost can be cut down. Further, another reason for the provision of the refrigerant pipe 24 is that because the refrigerant flowing through the refrigerant pipe 24 is originally low in pressure, an influence of a pressure loss due to routing through the control box 32 (pipe elongation) is small.

The fin structure 36 of the cooling unit 34 is formed integrally by aluminum or other metals, for example, as shown in Fig. 3. The plurality of plate-shaped fins 36a are provided at equal intervals in parallel to one another on one surface of a body portion 36b of the fin structure 36. Also, on the surface opposite to the surface on which the fins 36a is provided, the fin structure 36 has a plurality of grooves 36c to be fitted to portions of the refrigerant pipe 24 molded into a meandering shape.

As shown in Fig. 3, the plurality of grooves 36c of the fin structure 36 are formed so as to extend in a direction perpendicular to a parallel array direction of the plurality of fins 36a. As a result, the fin structure 36 can be manufactured by drawing or extrusion molding, thus being manufacturable with low cost as compared with other manufacturing methods (e.g., cutting work).

As shown in Fig. 2, the cooling unit 34 is placed below the control board 30 and apart from the control board 30. The purpose of this is to prevent the control board 30 from being wetted by condensed water generated on the surface of the cooling unit 34 (more specifically, on the surface of the fin structure 36 and the surface of the refrigerant pipe 24). In addition, as shown in Fig. 4, the cooling unit 34 may also be placed at a position horizontal to the control board 30 and moreover apart from the control board 30.

Preferably, in preparation for dropping down of the condensed water generated on the surface of the cooling unit 34, a dish-shaped dew receiving pan 38 for receiving condensed water is provided under the cooling unit 34. With this measure, component members of the air conditioner 10 located below the cooling unit 34 can be prevented from being wetted by the condensed water.

In addition, as shown in Fig. 2 (or Fig. 4), a drain pipe 40 for draining condensed water in the dew receiving pan 38 to outside of the control box 32 may be connected to a bottom of the dew receiving pan 38.

In addition to the cooling unit 34, another means for cooling the control board 30 may be provided.

A fin structure 42 other than the fin structure 36 of the cooling unit 34 may be attached directly to the control board 30, especially to a high-heat generating portion (e.g., heat-generating element) of the control board 30. This fin structure 42 is so designed as to fulfill heat exchange between the control board 30 and air of outside of the control box 32.

More specifically, the fin structure 42 is formed from, for example, aluminum and has a plurality of fins 42a, as in the fin structure 36 of the cooling unit 34. The fins 42a of the fin structure 42 are formed so as to be exposed outside of the control box 32. Also, the fins 42a are provided so as to be positioned downstream of a fan (not shown) for discharge of air around the outdoor heat exchanger 14 to outside of the outdoor unit. With the aid of such a fin structure 42, the control board 30 is cooled by the fan (not shown) of the outdoor unit.

Moreover, a fan 44 for forcedly stirring the air of the control box 32 may also be provided in the control box 32. By stirring the air in the control box 32, the fan 44 makes the temperature distribution in the control box 32 uniform, serving a role of enhancing the cooling efficiency of the control board 30.

By forcedly stirring the air in the control box 32, the fan 44 also can suppress generation of condensed water on the surface of the cooling unit 34. More concretely, since air around the cooling unit 34 is moved by the fan 44, condensed water is less likely to occur on the surface of the cooling unit 34, or condensed water, even in its occurrence, is less likely to grow large, as compared with the case in which the fan 44 is not present.

Preferably, the fan 44 is placed so as to blow air toward the fin structure 36 of the cooling unit 34 as shown in Fig. 2 (or Fig. 4). By the air blow of the fan 44 toward the fin structure 36, air cooled by the cooling unit 34 is diffused overall in the control box 32. Besides, the flow of air around the cooling unit 34 becomes faster, so that condensed water becomes even less likely to occur on the surface of the cooling unit 34.

Further, for suppression of heat transfer from outside to inside of the control box 32, preferably, the internal space of the control box 32 is heat insulated by a heat insulating material 46. The heat insulating material 46 is provided, for example, on an outer surface of the control box 32 as shown in Fig. 2. By this heat insulating material 46, a cooling effect for the control board 30 by the cooling unit 34 is improved as compared with the case in which the heat insulating material 46 is not provided. Although it is desirable that the heat insulating material 46 is provided on the outer surface of the control box 32 from the viewpoint of effective use of the space inside the control box 32, yet the heat insulating material 46 may also be provided on an inner surface of the control box 32.

The heat insulating material is exemplified by fiber heat insulating materials such as glass wool, foaming heat insulating materials such as urethane foam, vacuum heat insulating materials, and the like. It is preferable to use a vacuum heat insulating material, which is higher in heat insulation performance than heat insulating materials. The vacuum heat insulating material is exemplified by one formed by packing glass fiber with laminate film and reducing its internal pressure.

According to this embodiment, the cooling unit 34 for cooling of the air inside the control box 32 is placed at a position within the control box 32 below the control board 30 and apart from the control board 30 or at a position within the control box 32 horizontal relative to the control board 30. As a result of this, there can be realized an air conditioner 10 in which wetting of the control board 30 by condensed water generated on the surface of the cooling unit 34 is suppressed so that the air conditioner is high in reliability.
Although the present invention has been fully described by way of the above-described embodiment, the invention is not limited to the embodiment.

For example, although the fan 44 for forcedly stirring air in the control box 32 is placed within the control box 32 in the above embodiment, yet the fan 44 may be omitted if enough cooling for the control board 30 by the cooling unit 34 is fulfilled.

The above description has been made on an air conditioner in which the refrigerant flows through the compressor 12, the outdoor heat exchanger 14, the pressure reduction unit 16 and the indoor heat exchanger 18 in order, i.e. cooling operation is performed. However, the present invention is not limited to this. The invention is also applicable to an air conditioner 10 in which the refrigerant flows through the compressor 12, the indoor heat exchanger 18, the pressure reduction unit 16 and the outdoor heat exchanger 14 in order, i.e. heating operation is performed.

Further, the cooling unit 34 is so designed as to cool the air inside the control box 32 by using the whole refrigerant that flows within the refrigerant pipe 24 in the above embodiment However, the invention is not limited to this, and it is also allowable that part of the refrigerant that flows through any one of the refrigerant pipes 22 - 26 is used for the cooling of the air inside the control box 32.

For example, the cooling unit may also be made up by providing a bypassing pipe which is branched from a portion of the refrigerant pipe 24 close to a downstream side of the pressure reduction unit 16, extends through within the control box 32, and reaches a portion of the refrigerant pipe 24 close to an upstream side of the indoor heat exchanger 18, with a fin structure attached on this bypassing pipe. In this case, although cooling power for the control board 30 decreases, the cooling power of the air conditioner 10 is improved, as compared with the above embodiment.

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such Changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.

INDUSTRIAL APPLICABILITY

The present invention, in which air inside the control box is cooled by using a refrigerant, is applicable not only air conditioners but also refrigerators or other like devices involving use of refrigerants.

REFERENCE SIGNS LIST

10 air conditioner 12 compressor 14 outdoor heat exchanger 16 pressure reduction unit 18 indoor heat exchanger 30 control part (control board) 32 control box 34 cooling unit

CLAIMS

1. A cooling device for cooling a control part housed in a control box of an air conditioner, the air conditioner having a compressor, an outdoor heat exchanger, a pressure reduction unit, an indoor heat exchanger, and pipes for connecting these members so that a refrigerant flows therethrough, the cooling
device comprising

a cooling unit which is placed at a position within the control box below the control part and apart from the control part or at a position within the control box horizontal relative to the control part and which serves for cooling air inside the control box through heat exchange with the refrigerant.

2. The cooling device according to Claim 1, wherein the cooling unit comprises:

an intra-control box pipe placed within the control box and serving for the refrigerant to flow therethrough; and

a fin structure provided with a plurality of fins and attached on the intra-control box pipe.

3. The cooling device according to Claim 2, wherein the intra-control box pipe of the cooling unit is part of a pipe that connects the pressure reduction unit and the indoor heat exchanger to each other.

4. The cooling device according to any one of Claims 1 to 3, further comprising a dew receiving pan serving for receiving condensed water and placed below the cooling unit.

5. The cooling device according to any one of Claims 1 to 4, further comprising a heat insulating material for heat-insulating an internal space of the control box.

6. The cooling device according to Claim 5, wherein the heat insulating material is a vacuum heat insulating material.

7. An air conditioner including the cooling device as defined in any one of Claims 1 to 6.