JP2000234892A - Method for reducing heat exchanger and heat exchanger manufactured by that method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reducing a heat exchanger while sustaining good drainage performance and heat exchanging efficiency, and a heat exchanger manufactured by that method. SOLUTION: In a method for reducing a heat exchanger provided with corrugate fins 2 for accelerating heat exchange at a core section for exchanging heat between a heat exchanging medium and the outer air, fin pitch B of the corrugate fins 2 is reduced when the length of the core section in the ventilating direction, i.e., the core width, is reduced in order to compensate for lowering of heat exchanging efficiency incident to reduction of fin width. At least the surface of the corrugate fin 2 is subjected to ultra-hydrophilic treatment such that the contact angle with water becomes about 7 deg. or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used for an evaporator or the like of a vehicle air conditioner, and more particularly to a method for downsizing while maintaining high performance and a heat exchanger manufactured by this method. About.

[0002]

2. Description of the Related Art Usually, a surface of a heat exchanger such as an evaporator is provided with a corrosion-resistant film for preventing corrosion and a hydrophilic film for improving drainage. As the hydrophilic film, silica-based and resin-based ones are mainly used, and in a normal use condition, an organic component or the like adhering to the surface is present, so that the contact angle θ with water (see FIG. 10) ) Is 1
It is about 0 to 20 °.

Further, most of the corrugated fins used in the heat exchanger have a fin pitch (B in FIG. 5A) of 3.5 mm or more. this is,
This is because the fin pitch is necessary to ensure the drainage between the fins. If the fin pitch is made smaller than this, moisture accumulates in the ventilation space between the fins, which hinders ventilation.

[0004]

On the other hand, there is a demand for reducing the size of the heat exchanger body due to restrictions on the mounting space, etc., but when the core width (A in FIG. 2B) is reduced, In addition, since the fin width (E in FIG. 4) must also be reduced, the surface area of the fin is reduced, and the heat exchange efficiency is reduced.

In order to solve the decrease in the heat exchange efficiency due to the decrease in the surface area, the shape element for increasing or decreasing the fin surface area such as the fin pitch is changed so as to increase the fin surface area. Although it is advantageous to reduce the fin pitch, etc., the use of the above-described conventional hydrophilic treatment does not allow the drainage between the fins to be ensured, resulting in a decrease in cooling performance and a freezing phenomenon of the heat exchanger. Will be.

Accordingly, an object of the present invention is to provide a method of reducing the size of a heat exchanger which can be reduced while maintaining good drainage and heat exchange efficiency, and a heat exchanger manufactured by the method. I do.

[0007]

In order to solve the above-mentioned problems, the present invention provides a heat exchanger having a corrugated fin for promoting heat exchange in a core portion in which a heat exchange medium and external air exchange heat. In the method of reducing the size of the corrugated fins, when reducing the core width, which is the length of the core portion in the ventilation direction, the fins of the corrugated fins in order to compensate for a decrease in heat exchange efficiency due to the reduction of the fin width of the corrugated fins. Reducing the pitch, at least on the surface of the corrugated fin,
The super-hydrophilic treatment is performed so that the contact angle with water is about 7 ° or less (claim 1).

According to the above method, even if the core width of the heat exchanger is reduced and the fin width of the corrugated fin is reduced, the fin pitch is reduced so as to increase the surface area of the fin and the surface of the fin is reduced. By performing the superhydrophilic treatment, the heat exchanger can be reduced in size while ensuring sufficient heat exchange efficiency and drainage between the fins.

[0009] As shown in Figs. 5 (a) and 5 (b), a geometrical element for increasing the surface area of the corrugated fin is a distance B between both peaks of the adjacent peaks facing in the same direction. In addition to the certain fin pitch, the louver gap which is the interval D between the louvers 15 formed by cutting and raising the flat portion of the corrugated fin, and the fin height which is the interval C between the tops of the mountain portions facing in opposite directions. There is.

Further, the inventor of the present invention has proposed the above fin pitch,
It has been found that there is a relationship between the louver gap and the fin height and the cooling performance, that is, the heat exchange efficiency, as shown in FIGS. 6, 7, and 8. According to this, the fin pitch, the louver gap, and the fin height are all
A peak is obtained at a certain value, and the cooling performance tends to decrease as the peak departs. This is because the surface area of the fin decreases as the distance from the peak increases, or the air permeability decreases as the surface area increases.

From the above, according to the present invention, the fin pitch is 2.0 to 3.4 mm (Claim 2), the louver gap is 0.15 to 0.80 mm (Claim 3), and the fin height is 4 mm. -9 mm (claim 4).

The corrugated fins formed using the above range are subjected to a superhydrophilic treatment, so that the fins can be made denser and drainage can be ensured. That is, it is possible to achieve both high density of fins and drainage even at a small fin pitch which could not be reached conventionally. This makes it possible to produce thin corrugated fins with excellent heat exchange efficiency and drainage even if the fin width is reduced, so that the heat exchanger can be made thinner while maintaining high performance. Can be.

In the conventional heat exchanger, the core width is set to be about 60 mm from the viewpoint of heat exchange efficiency and the like. However, as described above, excellent heat exchange efficiency and drainage are achieved. If a thin corrugated fin having properties is used, a heat exchanger exhibiting good performance can be provided even if the core width is reduced to a range of 30 to 56 mm (claim 5).

[0014] The superhydrophilic treatment can be performed by forming a hydrophilic film containing titanium oxide.

Titanium oxide is a photocatalyst that produces a strong oxidizing action when irradiated with weak ultraviolet light contained in sunlight, fluorescent light, or the like. The titanium oxide is contained in the hydrophilic film formed on the surface of the fin. As a result, hydrophobic components such as organic substances attached to the surface of the fin are oxidatively decomposed. For this reason, it is possible to obtain a super-hydrophilic state in which the hydrophilicity is maintained for a long time and the contact angle θ with water (see FIG. 10) is about 7 ° or less. Further, the titanium oxide not only decomposes the above-mentioned hydrophobic components, but also oxidizes and decomposes components that emit a bad odor, and thus has an effect of preventing bad odors at the same time.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

The heat exchanger 1 used in this embodiment shown in FIGS. 2 and 3 is formed of an aluminum alloy and is used for an evaporator or the like of a vehicle air conditioner. A plurality of tube elements 3 having a passage formed therein and a plurality of corrugated fins 2 for promoting heat exchange between the refrigerant and the air are alternately stacked.

The tube element 3 is constructed by joining two tube forming plates 10 in which the flow path forming portions 13 are bulged as shown in FIG. 3 so that the bulging portions face each other. Is done. A first communication hole 11 and a second communication hole 12 are formed at a lower end portion of the tube forming plate 10, and a folded wall portion 14 is formed at a substantially central portion of the tube forming plate 10.
Are formed. Thereby, the refrigerant flow path by the flow path forming part 13 becomes substantially U-shaped, and the refrigerant flowing from the first communication hole 11 is folded at the upper end of the folded wall part 14 as shown by the arrow in the drawing, The liquid flows out from the second communication hole 12.

Further, the first and second communication holes 11, 1
2 is connected to the first and second communication holes 11 and 12 of the adjacent tube element 3, respectively, to form a tank portion 4. Further, the tank portion 4 is provided with a refrigerant inlet 5 for guiding the refrigerant from the outside into the heat exchanger 1 and a refrigerant outlet 6 for allowing the refrigerant flowing inside the heat exchanger 1 to flow to the outside. In this embodiment, since the first communication holes 11 of the two tube elements 3 and 3 located near the center among the plurality of tube elements 2 do not communicate with each other, As shown in FIG. 3 (a), the flowing refrigerant flows through the heat exchanger 1 inside the heat exchanger 1.
After reciprocating (four passes), the refrigerant flows out from the refrigerant outlet 6.

The corrugated fin 2 shown in FIG. 4 is formed in a meandering shape in order to increase the surface area, and a louver 15 is formed by cutting and raising a plane portion. 5A and 5B, fin pitch B, fin height C, and louver gap D are provided as shape elements for changing the surface area of the corrugated fin 2. The fin pitch B is the distance between the tops of the adjacent peaks facing in the same direction, the fin height C is the distance between the tops of the peaks facing in opposite directions, and the louver gap D is This is the interval formed between the adjacent louvers 15.

Hereinafter, a method of reducing the core width A of the heat exchanger 1 will be described with reference to FIG. When the core width A (see FIG. 2A) of the heat exchanger 1 is reduced, the fin width E of the corrugated fin 2 (see FIG. 4) also needs to be reduced (step 20). For this reason, the area of the corrugated fin 2 that comes into contact with the air is reduced.
The heat exchange efficiency decreases. To compensate for this, in the next step 30, the fin pitch B is reduced, and the corrugated fins 2 are further densified, thereby improving the heat exchange efficiency.

However, when the space between the fins is increased, the surface area is increased, and at the same time, the ventilation space for the passage of air is narrowed, so that water and the like tend to accumulate in this space. Therefore, in the next step 40, the surface of the heat exchanger 1 including the corrugated fins 2 is subjected to a superhydrophilic treatment to ensure the drainage of the densified corrugated fins 2. Thereby, the heat exchanger 1 is maintained while maintaining high heat exchange efficiency and good drainage.
Can be reduced.

The corrugated fin 2 according to this embodiment
Means that the fin pitch B is equal to 7 as shown in FIG.
The louver gap D is formed in a range of 2.0 to 3.4 mm capable of exhibiting a performance of 80 to 80% or more.
In the range of 80 mm (see FIG. 7), the fin height C is 4
It is formed in a range of up to 9 mm (see FIG. 8). By using the corrugated fins 2, the core width A of the heat exchanger 1 is set to 30 to 30 while maintaining the heat exchange efficiency and the drainage property.
It can be reduced to 56 mm.

Further, the superhydrophilic treatment is performed by forming a hydrophilic film composed of a mixture of a water-retaining substance such as silica and titanium oxide on the surface of the corrugated fin 2. Titanium oxide is a photocatalyst that generates a strong oxidizing effect when irradiated with weak ultraviolet light contained in sunlight, fluorescent light, or the like, and oxidizes and decomposes organic dirt such as oil attached to the film surface. Therefore, it is possible to obtain a super-hydrophilic state in which the hydrophilicity is maintained for a long time and the contact angle θ with water (see FIG. 10) is about 7 ° or less. Also,
The titanium oxide not only decomposes the hydrophobic component, but also oxidizes and decomposes the component that emits offensive odor, so that the effect of preventing odor can be obtained at the same time.

Incidentally, the hydrophilic film may be formed on an upper layer of a corrosion-resistant film containing chromium. According to this, the corrosion of the base material of the entire heat exchanger 1 including the corrugated fins 2 can be prevented.

Further, the method for reducing the size of the heat exchanger according to the present invention is not limited to the laminate type heat exchanger as shown in FIGS. 2 and 3, but the serpentine as shown in FIG. 9 (a). It can be used even if it is a mold or a separate tank type as shown in FIG. 9 (b).

[0027]

As described above, according to the present invention, the corrugated fins can be densified without deteriorating the drainage properties, so that a high-performance, thin-width heat exchanger can be manufactured.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a flow of a method for reducing a heat exchanger according to the present invention.

FIG. 2 (a) is a front view showing a heat exchanger according to an embodiment of the present invention, and FIG. 2 (b) is a side view of the heat exchanger.

FIG. 3 (a) is a perspective view showing a heat exchanger,
FIG. 3B is a perspective view showing a tube forming plate constituting the tube element.

FIG. 4 is a perspective view showing a corrugated fin used in a heat exchanger.

5A is a cross-sectional view showing a structure of a corrugated fin, and FIG. 5B is a cross-sectional view showing a structure of a louver formed on the corrugated fin.

FIG. 6 is a graph showing a relationship between a fin pitch of a corrugated fin and cooling performance.

FIG. 7 is a graph showing a relationship between a louver gap and cooling performance.

FIG. 8 is a graph showing a relationship between a fin height of a corrugated fin and cooling performance.

FIG. 9 (a) is a schematic view showing a serpentine type heat exchanger, and FIG. 9 (b) is a perspective view showing a separate tank type heat exchanger.

FIG. 10 is a schematic diagram showing a contact angle with water.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Corrugated fin 3 Tube element 4 Tank part 5 Refrigerant inflow port 6 Refrigerant outflow port 10 Tube formation plate 11 1st communication hole 12 2nd communication hole 13 Channel formation part 14 Folding wall part 15 Louver A core Width B Fin pitch C Louvre gap D Fin height E Fin width

Claims (6)

[Claims] 1. A method for reducing the size of a heat exchanger having a corrugated fin for promoting heat exchange in a core part where heat exchange between a heat exchange medium and outside air is performed, comprising: When a certain core width is reduced, the fin pitch of the corrugated fin is reduced to compensate for a decrease in heat exchange efficiency due to a reduction in the fin width of the corrugated fin, and at least on the surface of the corrugated fin, water and A super-hydrophilic treatment so that the contact angle of the heat exchanger becomes approximately 7 ° or less. 2. The heat exchanger manufactured by the heat exchanger reducing method according to claim 1, wherein the fin pitch of the corrugated fins is 2.0 to 3.4 mm. 3. The heat exchanger according to claim 2, wherein a louver for increasing a surface area is formed on the corrugated fin, and a gap between the louvers is 0.15 to 0.80 mm. . 4. The fin height of the corrugated fin is 4
The heat exchanger according to claim 2, wherein the heat exchanger has a length of 9 mm. 5. The core width of the heat exchanger is 30 to 56 mm.
The heat exchanger according to claim 2, 3 or 4, wherein 6. The heat exchanger according to claim 1, wherein a hydrophilic film containing titanium oxide is formed as the superhydrophilic treatment.