WO2012014934A1

WO2012014934A1 - Serpentine heat exchanger for an air conditioner

Info

Publication number: WO2012014934A1
Application number: PCT/JP2011/067087
Authority: WO
Inventors: 直栄佐々木; 紀寿磯村; 史郎柿山
Original assignee: 住友軽金属工業株式会社
Priority date: 2010-07-27
Filing date: 2011-07-27
Publication date: 2012-02-02
Also published as: KR20130036762A; JPWO2012014934A1; CN103026165B; CN103026165A; KR20150029728A

Abstract

The disclosed serpentine heat exchanger for an air conditioner effectively minimizes losses in heat-exchange performance due to condensation and is capable of adequately accommodating efforts to reduce the size of air conditioners. Said serpentine heat exchanger (10) comprises a plurality of fin groups (14) and a heat-exchanger pipe (16). Each fin group (14) is formed by arranging a large number of fins (12), each comprising a metal plate with a prescribed coating layer formed on at least one surface, parallel to each other at intervals of 0.6-5.0 mm in a direction (y direction) perpendicular to the direction (x direction) in which a heat-exchange fluid, namely air, flows. The plurality of fin groups (14) are arranged in a row at a constant distance from each other in a direction (z direction) perpendicular to the x direction and the y direction. The heat-exchanger pipe (16) is laid out in a serpentine configuration so as to penetrate each fin group (14) in turn.

Description

Serpentine heat exchanger for air conditioner

The present invention relates to a serpentine heat exchanger in which heat is exchanged between a heat exchange fluid such as air and a refrigerant, and more particularly to a serpentine heat exchanger suitably used as a heat exchanger for an air conditioner. is there.

Conventionally, a cross fin tube type heat exchanger has been mainly used as a heat exchanger for an air conditioner. This cross fin tube heat exchanger is formed by joining a plurality of heat transfer tubes bent in a hairpin to a plurality of fins in the vertical direction and expanding the heat transfer tubes to join the fins and the heat transfer tubes. It is structured. And in such a heat exchanger, while circulating a predetermined | prescribed refrigerant | coolant in a heat exchanger tube, while allowing air to flow along a fin perpendicularly | vertically with respect to a heat exchanger tube, a refrigerant | coolant and air are made to flow. Heat exchange takes place between them.

Moreover, such a cross fin tube type heat exchanger is generally composed of aluminum or aluminum alloy fins and copper or copper alloy heat transfer tubes, and a plurality of heat transfer tubes per fin. It is structured to be inserted. In an indoor heat exchanger of an air conditioner, for example, as disclosed in Japanese Patent Laid-Open No. 2008-138913 (Patent Document 1), an arc-shaped heat that covers a scroll fan is disclosed. An exchanger or a heat exchanger having a multi-stage bent shape is used. Moreover, in the outdoor heat exchanger of an air conditioner, a flat plate heat exchanger or a heat exchanger having a shape obtained by bending a flat plate is generally used.

And such a cross fin tube type heat exchanger is normally manufactured in the following processes. That is, first, an aluminum plate fin in which a plurality of predetermined assembly holes are formed is formed by pressing or the like. Next, after a plurality of the obtained aluminum plate fins are laminated at a predetermined interval, a separately manufactured heat transfer tube is inserted into the assembly hole. The heat transfer tube used here shall be provided with a hairpin bending process after cutting the groove with a predetermined groove on the inner surface by rolling or the like to a predetermined length. It becomes. The heat transfer tube is fixed to the aluminum plate fin by expanding the tube using various known methods, and then the U-bend tube is brazed to the end of the heat transfer tube opposite to the side subjected to the hairpin bending process. The target cross fin tube type heat exchanger is manufactured through the attaching process.

However, in order to manufacture a cross fin tube type heat exchanger by such a process, a large capital investment is required. For example, a large press device for forming aluminum plate fins and a press die thereof, a tube expansion device for expanding and fixing the aluminum plate fin and the heat transfer tube, and a tube expansion burette used therefor are required. In particular, the indoor heat exchanger and the outdoor heat exchanger have different fin shapes (such as slits and louvers) and heat transfer tube diameters. Factors that obstruct drastic model changes that would change the shape of the heat exchangers, because it is necessary to prepare press dies, expanded burettes, etc. It has become.

Furthermore, also in the brazing process, which is the final process when assembling the heat exchanger, there are many brazed locations such as connecting the heat transfer tubes with U-bend tubes, resulting in a large work load and increased energy costs. There was a problem. In addition, there is a possibility of quality defects such as burning of aluminum fins occurring during brazing and leakage from the brazing part, and a heat exchanger with as few brazing points as possible is desired. It is.

On the other hand, as a heat exchanger used for a refrigerator or the like, conventionally, a large number of holes are formed in one large plate-like aluminum fin as described above, and a cooling pipe is passed through the hole. A cross fin tube type heat exchanger is used, in which fins and cooling pipes are crimped by expansion, brazed at the end of each cooling pipe with a U-shaped connecting pipe, and communicated with each other. However, this also had the same problem as above.

Under such circumstances, a heat exchanger used in a refrigerator or the like is composed of a large number of plate fins arranged in parallel and a refrigerant pipe penetrating these fins. A fin-and-tube heat exchanger (serpentine heat exchanger) of an independent fin type in which the plate fins are arranged in rows and stages with respect to the refrigerant pipe. Many have been clarified (see Patent Documents 2 to 4). According to such a serpentine heat exchanger, since the heat exchanger is configured by bending the refrigerant pipe to which the independent fin group is attached in a zigzag manner, it is possible to reduce brazing points. The productivity can be improved, and the heat exchange performance can be improved by the leading edge effect obtained by using independent fins.

For this reason, the application of such a serpentine heat exchanger is also being studied in heat exchangers for air conditioners, but most of the actual heat exchangers for air conditioners are used. The cross fin tube type heat exchanger as described above has been used, and a serpentine heat exchanger has not been adopted so far. This is because the heat exchanger for the air conditioner is a heat exchanger (2 to 3 stages) with a relatively thin structure in the air flow direction compared to the heat exchanger for the refrigerator. This is because the effect obtained by using the fin is considered to be small.

In addition, since the heat exchangers described in Patent Documents 2 to 4 are designed as heat exchangers for cooling systems such as refrigerators, the heat transfer tube pitch and fin spacing are used to suppress blockage between fins due to frost formation. (Fin pitch) is enlarged, and the heat transfer area on the air side is reduced. On the other hand, in a heat exchanger for an air conditioner, it is necessary to suppress clogging between fins due to condensation. Under such circumstances, conventional serpentine heat exchangers such as the heat exchangers described in Patent Documents 2 to 4 are difficult to apply as they are as heat exchangers for air conditioners. There was.

By the way, in recent years, due to soaring cost of copper bullion, which is a material, heat exchangers for air conditioners have been developed from conventional fin fin tube type heat exchangers composed of aluminum fins and copper heat transfer tubes. There is a movement to convert to an all-aluminum heat exchanger, in which all heat transfer tubes are made of aluminum or aluminum alloy.

In particular, in indoor units, heat exchangers that can sufficiently cope with the remarkable downsizing seen in recent years are desired. In response to such demands, serpentine heat exchangers have independent fins. It is expected to improve heat exchange performance due to the leading edge effect, etc., and has the possibility of being able to cope with compactness. Furthermore, in terms of manufacturing air conditioners, heat exchangers for indoor units and outdoor units It is possible to simplify the process by sharing as much as possible. From these viewpoints, development of a serpentine heat exchanger that is advantageously used as a heat exchanger for an air conditioner is desired.

JP 2008-138913 A Japanese Utility Model Publication No. 5-8265 JP-A-5-265941 JP 2002-243382 A

Here, the present invention has been made in the background of such circumstances, and the problem to be solved is that a decrease in heat exchange performance due to condensation is effectively suppressed, and an air conditioner An object of the present invention is to provide a serpentine heat exchanger for an air conditioner that can sufficiently cope with downsizing.

In the present invention, in order to solve such problems, the heat exchange fluids are arranged in parallel to each other at a predetermined interval in the direction (y direction) perpendicular to the flow direction (x direction) of the heat exchange fluid. A plurality of fin groups composed of a large number of fins are arranged in a row at a predetermined distance in the direction perpendicular to the x direction and the y direction (z direction) to form a multi-stage fin group In addition, in the form in which one or two metal heat transfer tubes are penetrated by one fin, the metal heat transfer tubes are arranged in a meandering form so as to sequentially penetrate the fin groups of the respective stages. (1) Each fin constituting the fin group has the same shape, and adjacent fins are arranged at intervals of 0.6 to 5.0 mm. (2) The fin is It is made of a pre-coated metal plate in which a single-layer or multi-layer coating layer is formed on at least one surface of the metal plate, and at least the outermost layer of the coating layer is made of a hydrophilic resin or a water-repellent resin. The gist of the present invention is a serpentine heat exchanger for an air conditioner that is a film layer. Here, as the shape of the fin, a shape such as a rectangle, a circle, or a polygon is preferably employed.

By the way, according to one of the preferred embodiments of the serpentine heat exchanger for an air conditioner according to the present invention, the metal plate is made of aluminum or an aluminum alloy.

Moreover, in one of the desirable aspects in the serpentine heat exchanger for an air conditioner of the present invention, the heat transfer tube is made of aluminum or an aluminum alloy, and according to another desirable aspect, The sacrificial anode effect by zinc is given to the outer surface.

Furthermore, according to another preferred embodiment of the serpentine heat exchanger for an air conditioner according to the present invention, the material of the metal plate is JIS A1050, JIS A1100, JIS A1200, JIS A7072, and JIS A1050, JIS. A1100 or JIS A1200 is an aluminum or aluminum alloy composed of any one of 0.1 to 0.5% by mass of Mn and / or 0.1 to 1.8% by mass of Zn, The material of the heat transfer tube is aluminum or an aluminum alloy made of any one of JIS A1050, JIS A1100, JIS A1200, and JIS A3003.

Furthermore, in another desirable aspect of the serpentine heat exchanger for an air conditioner according to the present invention, the heat transfer tube is made of copper or a copper alloy, and is still another desirable aspect. Accordingly, the material of the heat transfer tube is JIS H3300 C1220 or JIS H3300 C5010.

In addition, in such a serpentine heat exchanger for an air conditioner according to the present invention, advantageously, the inner surface of the metal heat transfer tube has a predetermined length with respect to the straight groove and the tube axis parallel to the tube axis direction. It is comprised so that it may have any 1 type, or 2 or more types of the cross groove comprised by the spiral groove | channel which has the following twist angle, or the groove | channel which cross | intersects in a pipe-axis direction.

In another desirable aspect of the serpentine heat exchanger for an air conditioner according to the present invention, the fin has a plurality of embossed portions protruding in the thickness direction and having a circular or elliptical bottom portion. It is configured as such.

Further, in the present invention, preferably, the fin is slit or louvered, and according to another desirable aspect, the projected area of the fin is The cross-sectional area defined by the outer diameter of the heat transfer tube is 3 to 30 times.

Furthermore, in another desirable embodiment of the serpentine heat exchanger for an air conditioner according to the present invention, the projected area of the fin is 200 to 1000 mm ² .

According to another preferred embodiment of the serpentine heat exchanger for an air conditioner according to the present invention as described above, the outer diameter of the metal heat transfer tube is 3 to 13 mm.

In another advantageous aspect of the serpentine heat exchanger for an air conditioner of the present invention, a surface treatment layer is provided on the surface of the metal plate, and on the surface treatment layer, A single-layer or multiple-layer coating layer is formed.

Furthermore, according to another preferred embodiment of the serpentine heat exchanger for an air conditioner according to the present invention, the hydrophilic resin is a polyvinyl alcohol resin, a polyacrylamide resin, a polyacrylic acid resin, a cellulose resin. It will be selected from the group consisting of resins and polyethylene glycol resins.

Furthermore, in another preferred embodiment of the serpentine heat exchanger for an air conditioner according to the present invention, the water-repellent resin is an epoxy resin, polyurethane resin, acrylic resin, melamine resin, fluorine It will be selected from the group consisting of resin based resins, silicone based resins, and polyester based resins.

In addition, in the present invention, a resin coating layer is advantageously formed on the surface of the metal heat transfer tube. Moreover, according to one of the other preferable aspects of this invention, the said resin-made coating-film layer contains a heat conductive filler.

By the way, in the present invention, there are provided a serpentine heat exchanger having the characteristic structure as described above, and fan means for circulating a heat exchange fluid in the x direction through the plurality of fin groups arranged in the z direction. In the equipped air conditioner,
An interval between adjacent fins in the fin group located in the first region where the wind speed during circulation of the heat exchange fluid by the fan means is large or a part thereof is defined as p _1, and 0 with respect to the wind speed in the first region. a .7 following wind speed, when the interval between adjacent fins in the fin group or a portion thereof located in a small second region of the wind speed was p _2, the following formula:
1.5 ≦ p ₂ / p ₁ ≦ 3.0
An air conditioner characterized in that the fin interval in the fin group or a part thereof is defined so as to satisfy the above is also the gist of the present invention.

According to one of the preferred embodiments of the air conditioner according to the present invention, the fin group located in the first area or a part thereof and the fin group located in the second area or a part thereof Are positioned on different stages in the z-direction.

Further, according to one of the other preferred embodiments of the air conditioner according to the present invention, the fin group located in the first region or a part thereof and the fin group located in the second region or A part thereof is configured to be located in the same step in the z direction.

Thus, in the serpentine heat exchanger for an air conditioner according to the present invention, the fin shape constituting each fin group is the same, and the interval (fin pitch) between adjacent fins on the metal heat transfer tube is the same. Further, each fin is made of a pre-coated metal plate in which a single-layer or multi-layer coating layer is formed on at least one surface of the metal plate. Since at least the outermost layer of the coating layer is made of a hydrophilic resin or a water-repellent resin, when used in an air conditioner, a decrease in heat exchange performance due to condensation is effectively suppressed. It is.

Further, in such a serpentine heat exchanger for an air conditioner, one or two heat transfer tubes are penetrated through a large number of fins constituting the fin group, and are configured by independent fin groups. The fin efficiency can be advantageously increased, and the heat interference (conduction) through the fins of adjacent heat transfer tubes can be cut off. As a result, it is possible to improve the heat exchange performance, thereby It is possible to advantageously realize a compact exchanger.

It is a perspective explanatory view showing an example of a serpentine heat exchanger for an air conditioner according to the present invention. It is a section explanatory view showing roughly an example at the time of applying the serpentine heat exchanger for air conditioners according to the present invention to the outdoor unit of an air conditioner. It is a section explanatory view showing roughly another example at the time of applying the serpentine heat exchanger for air conditioners according to the present invention to the outdoor unit of an air conditioner. It is sectional explanatory drawing which shows an example of the coating-film layer formed on the surface of the fin which comprises the serpentine heat exchanger for air conditioners according to this invention. It is an isometric view explanatory drawing which shows another different example of the serpentine heat exchanger for air conditioners according to this invention. It is an isometric view explanatory drawing which shows another different example of the serpentine heat exchanger for air conditioners according to this invention. It is an isometric view explanatory drawing which shows another different example of the serpentine heat exchanger for air conditioners according to this invention. It is explanatory drawing which shows another example of the fin which comprises the serpentine heat exchanger for air conditioners according to this invention, Comprising: (a) is a perspective explanatory drawing of the whole one fin, (b) is embossing It is a section explanatory view expanding and showing a section of a portion. It is explanatory drawing which shows the metal heat exchanger tube which comprises the serpentine heat exchanger for air conditioners according to this invention, (a) is sectional explanatory drawing which shows what was used for the heat exchanger shown in FIG. (B), (c), (d) is sectional explanatory drawing which each shows another different example used as a metal heat exchanger tube.

Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows an embodiment of a serpentine heat exchanger for an air conditioner (hereinafter also simply referred to as a serpentine heat exchanger or a heat exchanger) according to the present invention in the form of a perspective view. . In the heat exchanger 10, a plurality of fin groups 14 including a plurality of rectangular fins 12 arranged in parallel to each other and at a predetermined distance are arranged in parallel at a predetermined distance. At the same time, the metal heat transfer tubes 16 are arranged in a meandering manner, that is, in a serpentine shape via a bent portion 18 so as to sequentially penetrate the plurality of fin groups 14.

More specifically, the fin 12 is a pre-coated metal plate in which a single-layer or multi-layer coating layer is formed on at least one surface of a predetermined metal plate in a predetermined fin shape (here, a rectangular shape). An assembly hole into which the metal heat transfer tube 16 is inserted is provided at a substantially central portion of the rectangular shape, and a predetermined height is provided at the peripheral portion of the assembly hole. The collar portion is provided integrally with the fin 12. In addition, it is preferable that the metal plate which is a base material of the precoat metal plate which provides this fin 12 is comprised with aluminum or aluminum alloy like the past. Among them, from the viewpoint of excellent heat transfer and ensuring the strength as a fin, Mn is added to JIS A1050, JIS A1100 or JIS A1200 in addition to materials such as JIS A1050, JIS A1100, JIS A1200, etc. A material containing 0.1% to 0.5% by mass and / or about 0.1% to 1.8% by mass of Zn is advantageously used. . Further, when priority is given to the strength as the fin, the material of JIS A7072 is advantageously employed. Here, a symbol represented by a combination of an alphabet of “JIS A” and a four-digit number indicates an aluminum or aluminum alloy material defined in the JIS standard.

Furthermore, at least the outermost layer of the coating layer formed on the surface of the fin 12 is made of a hydrophilic resin or a water repellent resin. Examples of hydrophilic resins include polyvinyl alcohol resins (polyvinyl alcohol and derivatives thereof), polyacrylamide resins (polyacrylamide and derivatives thereof), polyacrylic resins (polyacrylic acid and derivatives thereof), and cellulose. Examples thereof include resin based on sodium (carboxymethylcellulose sodium, carboxymethylcellulose ammonium, etc.), polyethylene glycol resin (polyethylene glycol, polyethylene oxide, etc.) and the like. Examples of the water repellent resin include an epoxy resin, a polyurethane resin, an acrylic resin, a melamine resin, a fluorine resin, a silicon resin, and a polyester resin.

The projected area of the fin 12 is 3 to 30 times the cross-sectional area defined by the outer diameter of the heat transfer tube (metal heat transfer tube 16) from the viewpoint of achieving both heat exchanger miniaturization and heat exchange performance. It is preferable that The cross-sectional area defined by the outer diameter of the heat transfer tube indicates the cross-sectional area obtained from the outer diameter of the heat transfer tube after the metal heat transfer tube 16 is expanded and fixed to the assembly hole of the fin 12. For example, as shown in FIG. 1, in a serpentine heat exchanger in which one heat transfer tube passes through one fin, if the outer diameter of the expanded metal heat transfer tube 16 is 6.5 mm, The cross-sectional area is 33.2 mm ² . When the projected area of the fin is less than three times the cross-sectional area defined by the outer diameter of the heat transfer tube, the fin is too small for the heat transfer tube, so that sufficient heat exchange performance is achieved. On the other hand, if the cross-sectional area exceeds 30 times, the heat exchanger becomes large and not practical. In particular, the projected area of the fin is preferably 200 to 1000 mm ² from the viewpoint of achieving both a reduction in size of the heat exchanger and heat exchange performance. If the projected area of the fin is less than 200 mm ² , sufficient heat exchange performance may not be obtained. On the other hand, if it exceeds 1000 mm ² , the heat exchanger becomes large and impractical. Because.

Then, as shown in FIG. 1, a plurality of such fins 12 are in a direction (y direction in FIG. 1) perpendicular to the flow direction of air as the heat exchange fluid (x direction in FIG. 1). In other words, the thickness direction of the plate is perpendicular to the air flow direction, and the

adjacent fins

12 and 12 are parallel to each other and have an interval (fin pitch) of 0.6 to 5.0 mm, preferably 1 The fin group 14 is formed by being arranged so as to have an interval of 0.0 to 4.0 mm. Further, a plurality of such fin groups 14 composed of a large number of fins 12 are arranged such that each fin group 14 has a certain distance from each other in the direction perpendicular to the x and y directions (the z direction in FIG. 1). By being arranged in a row at a distance, it is configured to exhibit a flat plate shape as a whole.

On the other hand, the metal heat transfer tube 16 is a tube having a substantially circular cross section formed of a predetermined metal material as in the prior art. And as a metal material which comprises this metal heat exchanger tube 16, Preferably, aluminum or an aluminum alloy, or copper or a copper alloy will be used.

Here, in the case where the metal heat transfer tube 16 is made of an aluminum material or an aluminum alloy material, from the viewpoint of manufacturability (extrusibility), among JIS A1050, JIS A1100, JIS A1200, and JIS A3003 Any one kind of material is advantageously employed, but in order to further improve the corrosion resistance of the heat transfer tube, the following is preferable.

That is, the metal heat transfer tube 16 is made of any one of aluminum or aluminum alloy of JIS A1050, JIS A1100, JIS A1200, and JIS A3003 as described above, and the outer surface thereof is zinc sprayed and contains zinc. It is possible to improve the corrosion resistance of the heat transfer tube by forming a sacrificial anode material layer by flux (KZnF ₄ ), zinc plating or the like on the outer surface of the heat transfer tube and imparting the sacrificial anode effect by zinc. Alternatively, the metal heat transfer tube 16 is made of any one of the materials of JIS A1050, JIS A1100, JIS A1200, and JIS A3003, and the metal plate constituting the fin 12 is made of these aluminum. Alternatively, the corrosion resistance of the heat transfer tube can be improved by using Zn-containing JIS A7072 material that is electrochemically lower than the aluminum alloy.

Further, the heat transfer tube 16 can be constituted by a clad tube having a double tube wall structure composed of an inner core material layer and an outer skin material layer in the radial direction. Therefore, the JIS A1050, JIS A1100, JIS A1200, JIS A3003, etc. are adopted as the material of the core material layer, and JIS A7072 etc. are adopted as the material of the skin material layer, and the same effect as above is obtained. It will be realized together. As the cladding rate, which is the thickness of the outer skin material layer, a value that is 3 to 20% of the total thickness of the tube wall is employed. If this cladding ratio is less than 3%, the sacrificial anode effect of the skin material is small, the through-holes are likely to be vacant, causing a problem of poor corrosion resistance, and if the cladding ratio exceeds 20%, the tube wall thickness On the other hand, the ratio of the core material layer becomes low, and problems such as a decrease in strength are likely to occur.

On the other hand, when the metal heat transfer tube 16 is made of copper or a copper alloy, a material such as JIS H3300 C1220 or JIS H3300 C5010 is advantageously employed from the viewpoint of heat transfer. Become. In addition, the symbol consisting of the combination of “JIS H3300” and “C + four-digit number” used here also indicates the copper or copper alloy material defined in the JIS standard.

In the metal heat transfer tube 16 made of such a predetermined metal material, the outer diameter is appropriately determined so as to satisfy both the demand for downsizing the target serpentine heat exchanger 10 and the heat exchange performance. However, it is preferably 3 to 13 mm. This is because heat transfer tubes with an outer diameter of less than 3 mm are difficult to manufacture as tubes, and those with an outer diameter of more than 13 mm are larger for heat exchangers employing such thick heat transfer tubes. This is because it is not practical.

In addition, the straight portion of such a single metal heat transfer tube 16 sequentially passes through the assembly holes formed in the substantially central portions of the plurality of fins 12 constituting the fin group 14 described above, and the metal The outer peripheral surface of the heat transfer tube 16 and the collar inner peripheral surface of the peripheral edge of the assembly hole of the plurality of fins 12 are brought into close contact with each other and fixed (coupled). It should be noted that, for such a connection between the fin 12 and the metal heat transfer tube 16, various conventionally known methods are appropriately selected and used. An assembly hole with a collar having an inner diameter slightly larger than the outer diameter of the heat transfer tube 16 is opened, and after inserting the metal heat transfer tube 16 into such an assembly hole, the inside of the metal heat transfer tube 16 By inserting a tube expansion plug into the metal heat transfer tube 16 to increase the outer diameter of the metal heat transfer tube 16, the outer peripheral surface of the metal heat transfer tube 16 and the inner peripheral surface of the assembly hole provided in the fin 12 (collar inner peripheral surface) The method of adhering to each other is preferably employed.

In this way, as shown in FIG. 1, the metal heat transfer tube 16 is perpendicular to the flow direction (x direction) of the air that is the heat exchange fluid and the arrangement direction (y direction) of the multiple fins 12. So as to penetrate through a plurality of fin groups 14 arranged in a certain direction (z direction) in order, and in a meandering form, in other words, by being arranged in a serpentine shape, the entire plate is substantially flat. A serpentine heat exchanger 10 for an air conditioner having a shape is configured.

By the way, the following methods can be exemplified to make the metal heat transfer tube 16 meandering and to have the desired shape of the heat exchanger 10. That is, first, a plurality of fin groups 14 are arranged at a predetermined interval with respect to one long straight metal heat transfer tube 16. Thereafter, a portion where the fin group 14 of the metal heat transfer tube 16 is not disposed is bent into a U shape, thereby forming a bent portion 18 to have a meandering shape, as shown in FIG. Thus, this is a method of forming the desired shape of the heat exchanger 10.

In addition, the serpentine heat exchanger 10 for air conditioners which exhibits the substantially flat shape illustrated here is suitably employ | adopted as a heat exchanger for outdoor units of an air conditioner as shown, for example in FIG. It will be. That is, in FIG. 2, the outdoor unit 20 of the air conditioner is schematically shown in the form of a sectional view, in which the serpentine heat exchanger 10 for an air conditioner disposed in the outdoor unit 20. On the other hand, heat is exchanged between the refrigerant and the air by circulating air as a heat exchange fluid by the fan 22.

Moreover, the example which used this serpentine heat exchanger 10 for air conditioners as a heat exchanger which takes the form which bent the flat plate so that the side view may become L shape is shown by FIG. . There, two such L-shaped heat exchangers (10, 10 ′) are used in combination so that the

heat exchangers

10, 10 ′ have a rectangular shape in plan view. In addition, the fan 22 is installed on the upper part of the outdoor unit 20 so as to be positioned above the rectangular shape. Then, by the operation of the fan 22, the air as the heat exchange fluid is circulated through the two

heat exchangers

10 and 10 ′ combined in a rectangular cylindrical shape as indicated by arrows, Heat exchange between the refrigerant and the air can be performed.

Therefore, in the serpentine heat exchanger 10 for an air conditioner having a structure according to the present invention as described above, the fins 12 are spaced on the metal heat transfer tube 16 at intervals of 0.6 to 5.0 mm (fin pitch). ) To form the fin group 14, even when used in an air conditioner, a decrease in heat exchange performance due to condensation is effectively suppressed. . That is, if the fin pitch is less than 0.6 mm, water (condensation liquid) generated by dew condensation is unlikely to fall from the fin surface even when the film layer described later is provided on the fin. While the exchange performance is degraded, such condensed liquid may be pushed out by the air blown to cause water splashing in the room. On the other hand, if the fin pitch exceeds 5.0 mm, the fin pitch is too large. Therefore, in the heat exchanger of the same size, the number of fins is inevitably reduced, and the heat exchange performance may be deteriorated.

Further, in the heat exchanger 10, the heat exchanger is configured by a plurality of independent fin groups 14, and the fins are configured by assembling a large number of heat transfer tubes on one fin.・ Fin efficiency can be increased more favorably than an and-tube heat exchanger, and thermal interference (conduction) through the fins of adjacent heat transfer tubes can be effectively suppressed or cut off. Thus, the heat exchange performance can be advantageously improved, so that the heat exchanger 10 can be made compact.

Furthermore, a single-layer or multiple-layer coating layer is formed on the surface of the fin 12, and at least the outermost layer of the coating layer is formed of a hydrophilic resin or a water-repellent resin. Therefore, the heat exchange performance of the heat exchanger 10 can be advantageously maintained even in a situation where the temperature difference between the set temperature of the air conditioner and the outside air temperature is significant and dew condensation occurs on the fin surface. . That is, when a coating layer made of a hydrophilic resin is provided as the outermost layer, water generated by condensation forms a film on the surface of the outermost layer. It is possible to effectively suppress an increase in resistance when passing between the fins and stably maintain high heat exchange performance. On the other hand, even when a coating layer made of a water-repellent resin is provided as the outermost layer, the water generated by condensation on the surface of the outermost layer falls smoothly from the fin surface as fine water droplets. Since it can be effectively discharged out of the fin, the increase in ventilation resistance due to condensed water is effectively suppressed, as in the case where a coating layer made of hydrophilic resin is provided as the outermost layer. Thus, the heat exchange performance can be maintained.

Of course, it is possible to use a pre-coated metal plate provided with a single coating layer made of a hydrophilic resin or a water-repellent resin as the fins 12, but preferably, a metal plate serving as a substrate is used. First, a corrosion-resistant coating layer made of epoxy resin, urethane resin, polyester resin, vinyl chloride resin or the like is formed on the surface, and further, a coating layer made of the above-mentioned hydrophilic resin or the like is formed on the surface. A pre-coated metal plate provided with a plurality of coating layers obtained by forming is used. That is, it is possible to improve the corrosion resistance of the fins 12 by providing such a corrosion-resistant coating layer on the surface of the metal plate to be the substrate. The thickness of each coating layer formed on the surface of the metal plate in this manner is preferably 0.1 to 5.0 μm per single layer. This is because when the thickness of each coating layer is less than 0.1 μm, the effects of each coating layer may not be enjoyed advantageously. On the other hand, even if a coating layer having a thickness of more than 5.0 μm is provided, the effect of each coating layer is already in a saturated state, so it is only costly to form such a coating layer. It becomes.

In addition, when a coating layer made of a hydrophilic resin or a water-repellent resin or a corrosion-resistant coating layer is provided on the surface of the metal plate constituting the fin 12, a base treatment layer 32 is previously formed on the surface of the metal plate 30. It is preferable that this is done (see FIG. 4). By providing such a base treatment layer 32, it is possible to improve the adhesion between the metal plate and each of the coating layers (34, 36) described above. Here, as such a base treatment layer, chromate treatment using phosphate chromate, chromate chromate, etc., and other than chromium compounds, titanium phosphate, zirconium phosphate, molybdenum phosphate, zinc phosphate, titanium oxide, oxidation Examples thereof include a film layer obtained by a chemical film treatment (chemical conversion treatment) such as non-chromate treatment using zirconium or the like. The chemical film treatment method includes a reaction type and a coating type. In the present invention, any method can be adopted.

As described above, one of the typical embodiments of the heat exchanger according to the present invention and the manufacturing method thereof have been described in detail. However, these are merely examples, and the present invention is not limited to such implementation. It should be understood that the present invention is not construed as being limited in any way by the specific description of the forms.

For example, in the above-described embodiment, the intervals (fin pitches) between the

adjacent fins

12 and 12 are all equally spaced. Of course, it is possible to set different fin pitches between the fin groups 14 or within one fin group 14 depending on the fin 12 arrangement site in the group 14.

Specifically, in the refrigerant flowing through the metal heat transfer tube 16, the gas phase region and the liquid phase region in the vicinity of the refrigerant inlet / outlet are compared with the gas / liquid two-phase region in the intermediate portion of the refrigerant. Since the exchangeability is low and the heat transfer coefficient is clearly low, it is possible to increase the heat exchange efficiency by expanding the heat exchange area by narrowing the fin pitch at such a part.

Further, in the outdoor unit 20 of the air conditioner as shown in FIG. 3, when air is circulated to the

heat exchangers

10, 10 ′ by the fan 22, the upper region that is the closest region to the fan 22. The flow velocity of the air flowing between the fins 12 of the fin group 14 located at A is larger than the flow velocity of the air flowing between the fins 12 of the fin group 14 located in the lower region B, which is the region farthest from the fan 22. Become.

For example, the flow velocity Va of air flowing between the fins 12 in the fin group 14 in the upper region A is 1.5 to 2 times the flow velocity of air flowing between the fins 12 in the fin group 14 in the lower region B: Vb. In such a case, the interval between the adjacent fins 12 and 12 (fin pitch: p ₁ ) in the fin group 14 in the upper region A is narrowed for the purpose of improving the heat exchange performance. On the other hand, if the spacing (fin pitch: p ₂ ) between adjacent fins 12 in the fin group 14 in the lower region B is also set to the same fin pitch as the fin pitch: p ₁ , the fin group in the lower region B In 14, the ventilation resistance becomes too large, and the problem arises that the heat exchange performance as a whole deteriorates.

Then, to avoid the occurrence of such a problem, the fin pitch of the fin group 14 located farther lower region B from the fan 22: the p _2, the fin group 14 located in the upper region A close to the fan 22 It is preferable to expand the fin pitch at an appropriate ratio with respect to p ₁ . Therefore, in the present invention, paying attention to the flow velocity (wind velocity) of the air that is the heat exchange fluid in the regions A and B, the upper region A (first region) in which the wind velocity during air circulation by the fan 22 is large. a plurality of fins sites fin pitch in the group of fins 14 located) and p _1, is 0.7 or less of the wind against the wind speed at the upper stage region a, a small lower region B of the wind speed (second region) By restricting the relationship between the fin pitch 14 in the fin group 14 located at p ₂ and p ₂ , the ratio p ₂ / p ₁ is 1.5 or more and 3.0 or less (1.5 ≦ p ₂ / p ₁ ≦ 3.0), advantageously adopting a configuration that adjusts the fin pitch of the fin group 14 in each region to control the ventilation resistance and improve the overall heat exchange performance Will be.

When the value of p ₂ / p ₁ is less than 1.5, the effect of changing the ratio of the two fin pitches becomes insufficient, and it is difficult to expect improvement in heat exchange performance. When the value of p ₂ / p ₁ exceeds 3.0, the interval between

adjacent fins

12 and 12 of the fin group 14 located in the upper region A of each

heat exchanger

10 and 10 ′: p _{When 1} is 0.6 mm, which is the lower limit of the appropriate range for the fin pitch, an increase in ventilation resistance due to the attachment of condensed water on each fin 12 during heating operation causes a decrease in air-side heat transfer coefficient In addition, the air-side heat transfer coefficient is reduced, which causes a reduction in heat exchange performance.

Here, the above-described fin pitch: p ₁ is set as an interval between adjacent fins in at least one fin group 14 located in the upper region A that is the region closest to the fan 22. In general, however, the upper region A close to the fan 22 is positioned close to the fan 22 among the plurality of (n-step) fin groups 14 arranged in the z direction. The fin group 14 having n / 4 stages is included. Similarly, the fin pitch: p ₂ is adopted as an interval between adjacent fins in at least one fin group located in the lower region B, which is the region farthest from the fan 22. Among the plurality of (n-stage) fin groups 14 constituting the

heat exchangers

10 and 10 ′, it is advantageous to the n / 4-stage fin group 14 located in the region farthest from the fan 22. It will be applied to. In addition, even in the fin region 14 (n / 2 steps) in the intermediate region located between the upper region A and the lower region B, the wind speed of the fin group 14 is 0.7 times or less than the wind speed in the upper region A. In this case, the fin pitch (p ₂ ) is defined so as to satisfy the inequality related to p ₂ / p ₁ described above. The p ₁ is shown as an average fin pitch of at least one fin group 14 located in the upper region A, and p ₂ is at least one fin group 14 located in the lower region B. It is shown as the average fin pitch at.

Furthermore, the air in the fin group 14 located in the intermediate region between the upper region A and the lower region B of the plurality of (n stages) fin groups arranged in the z direction in each

heat exchanger

10, 10 ′. Since Vc has a relationship of Vb ≦ Vc ≦ Va, the fin pitch of the fin group 14 of the intermediate region of the plurality of fin groups 14 (generally, the number of stages of n / 2) is: p ₃ is preferably p ₁ ≦ p ₃ ≦ p ₂ .

The change in the flow velocity (wind speed) of the heat exchange fluid (air) as described above occurs between the

fin groups

14 and 14 located at different stages in the z direction, and different fin arrangements in the fin groups 14 of the same stage. The relationship between the fin pitches p ₁ and p ₂ described above is that they occur also between the fins 12 of one fin group 14 arranged at different positions in the tube axis direction of the heat transfer tubes 16. In either case, it will be applied.

Moreover, in the heat exchanger 10 in this embodiment, although the one metal heat exchanger tube 16 penetrated with respect to the one fin 12, as shown in FIG. The heat exchanger 40 having a structure in which the two fins 44 are formed by passing the two metal

heat transfer tubes

16 and 16 through the fins 42 may be used.

Furthermore, a shape in which a plurality of heat exchangers 10 are overlapped with respect to the flow direction of the heat exchange fluid (air), for example, as shown in FIGS. It is also possible to constitute one

serpentine heat exchanger

46, 48 for an air conditioner by overlapping each other at intervals. Thus, in the case where a plurality of flat plate-shaped heat exchangers 10 are overlapped with respect to the air flow direction, the fins of adjacent heat exchangers 10, such as the heat exchanger 46 shown in FIG. 6, are used. In other words, one of the fin groups 14 of the front heat exchanger 10 is adjacent to one of the fin groups 14 of the rear heat exchanger 10 in the flow direction of the heat exchange fluid. 7, so that one of the fin groups 14 of the front heat exchanger 10 is adjacent to the two fin groups 14 of the rear heat exchanger 10, as in the heat exchanger 48 shown in FIG. 7. It is also possible to arrange them so that the fins 12 of the adjacent heat exchangers 10 are staggered. However, from the viewpoint of heat exchange performance, as shown in FIG. 7, it is expected that better heat exchange efficiency can be expected by overlapping in a zigzag pattern. Further, in the case where a plurality of heat exchangers 10 are stacked in the flow direction of the air that is the heat exchange fluid in this way, the ventilation resistance is lowered by widening the fin pitch in a portion where high heat exchange efficiency cannot be expected. Is also possible. By reducing the ventilation resistance in this way, the flow of air, which is a heat exchange fluid, is improved, and sufficient air also flows through the heat exchanger 10 disposed on the rear side with respect to the air flow direction. It becomes possible to improve the heat exchange efficiency of the whole exchanger.

As the fins constituting the heat exchanger 10 (40, 46, 48), in addition to the illustrated fin 12 (42) having a substantially flat rectangular shape, for example, as shown in FIG. A fin 50 having a plurality of embossed portions 52 protruding on the surface in the thickness direction of the fin and having a bottom or outer shape of a circle or an ellipse is preferably used. By forming the embossed portion 52 on the fin surface in this manner, after the heat exchange air passing between the stacked fins 50 comes into contact with the embossed portion 52, the stacking direction (longitudinal direction) of the fins 50 and It is converted into a direction (lateral direction) perpendicular to the stacking direction, and these become an appropriate longitudinal spiral (hereinafter referred to as longitudinal vortex) and lateral spiral (hereinafter referred to as lateral vortex). The air between the fins is appropriately disturbed by such an appropriate spiral flow, and as a result, the heat exchange performance can be improved. When a fin-and-tube heat exchanger (serpentine heat exchanger) is used as an evaporator in a low-temperature environment as an outdoor unit in a cold region, such an appropriate swirl flow, particularly a vertical flow The vortex suppresses the retention of relatively low temperature air in the vicinity of the fin surface, and allows relatively high temperature air that tends to stay in the central part between the fins to contact the fin surface. Suppression of frost formation or growth of frost that has formed frost can be effectively suppressed.

Such an improvement in heat exchange performance due to the presence of the embossed portion 52 can also be realized by a cut-and-raised slit or a louver slit formed by slit processing or louver processing. Accordingly, such slit processing and louver processing are performed on the fins (12, 42) in accordance with a conventional method together with or instead of the embossing for forming the embossed portion 52.

Further, the pipe diameter of the metal heat transfer pipe 16 may be different depending on the part of the heat exchanger 10 depending on the flow characteristics of the refrigerant flowing in the pipe. For example, a heat transfer tube with a relatively small outer diameter is used in the liquid phase region, while a heat transfer tube with a relatively large outer diameter is used in the gas phase region, thereby improving the heat transfer coefficient in the tube and reducing the pressure loss. This can be advantageously achieved. When adopting a metal heat transfer tube having a different pipe diameter depending on the part of such a heat exchanger, a single long metal heat transfer pipe whose pipe diameter is appropriately changed at a desired part in the tube axis direction is used. In addition to using, for example, a metal heat transfer tube having a pipe diameter appropriately selected for each fin group 14 may be connected by a U-bend tube or the like to form a metal heat transfer tube having a meandering shape.

Further, in the embodiment exemplified above, a tubular body (see FIG. 9A) having a smooth inner surface is used as the metal heat transfer tube 16, but in the longitudinal direction on the inner surface of the heat transfer tube. It is also possible to employ a so-called internally grooved heat transfer tube in which parallel straight grooves, spiral grooves having a twist angle, or cross grooves having a groove shape in which the grooves intersect at a predetermined angle are formed. In this way, it is possible to further increase the heat exchange performance of the heat exchanger 10 by increasing the heat transfer area on the inner surface of the heat transfer tube and further complicating the flow of the refrigerant flowing through the heat transfer tube. It becomes. In addition, in the serpentine heat exchanger 10 that employs the inner surface grooved heat transfer tube as described above, the entire groove type inner surface grooved heat transfer tube may be employed, but other than that, for example, It is also possible to use an internally grooved heat transfer tube of a type having a different groove shape for each path constituting the fin group 14. The groove formed on the inner surface of the heat transfer tube in this manner preferably has a groove depth of 0.05 to 1.0 mm, and the number of grooves is preferably in a cross section perpendicular to the longitudinal direction of the heat transfer tube. By setting the length to 15 to 150, it is possible to effectively enhance the heat exchange performance.

Furthermore, the metal heat transfer tube 16 used in the present invention only needs to have an outer surface having a substantially circular shape. For example, as shown in FIGS. 9B, 9C, and 9D, the cross section is 1. In addition to the

multi-hole pipes

54, 56, and 58 partitioned by two partition boards 55, two

parallel partition boards

57 and 57, and two

crossing partition boards

59 and 59, various known multi-hole pipes Can be suitably employed.

In addition, as the metal heat transfer tube 16 constituting the serpentine heat exchanger 10, one having a resin coating layer formed on its surface is preferably used. The serpentine heat exchanger 10 described above is assembled by bringing the metal heat transfer tubes 16 and the fins 12 into close contact with each other by a method such as a mechanical tube expansion method, and assembling them. If the contact portion of the heat tube is viewed microscopically, a certain amount of air gap exists between the metal heat transfer tube 16 and each of the fins 12. However, if such voids are present, the contact thermal resistance between the fins and the heat transfer tubes is increased, and the heat exchange performance may be degraded. Therefore, in order to reduce the contact thermal resistance between them and effectively exhibit the performance of the heat exchanger, it is preferable that there is no gap between the metal heat transfer tubes 16 and the fins 12, Therefore, by forming a resin coating layer on the surface of the metal heat transfer tube 16, the generation of such voids is advantageously suppressed.

And as resin which comprises such a resin-made coating-film layer, other than thermoplastic resins, such as a polyethylene resin, the hydrophilic resin and water-repellent resin similar to what is formed in the fin 12 surface mentioned above, And epoxy resins, urethane resins, polyester resins, vinyl chloride resins, and the like. By forming a coating layer made of these various resins on the surface of the metal heat transfer tube 16, the following effects can be obtained. That is, for a thermoplastic resin such as a polyethylene resin, after assembling the fins 12 provided with collared holes to the metal heat transfer tube 16 having a coating layer made of a thermoplastic resin such as a polyethylene resin as the outermost layer, When heated above the melting point of a thermoplastic resin such as polyethylene resin and then cooled, the gap between the collar skirt formed on the periphery of the hole with the collar and the metal heat transfer tube is advantageous by the thermoplastic resin such as polyethylene resin. Since the contact area between the fins 12 and the metal heat transfer tubes 16 can be ensured larger, the heat exchange performance of the heat exchanger can be further improved. Further, by forming a coating film layer made of a hydrophilic resin or a water repellent resin on the metal heat transfer tube 16 as an outermost layer, the exposed portions (portions where no fins are assembled) of the metal heat transfer tube 16 are formed on the fin 12. It is possible to have the same function as. Furthermore, by providing a coating layer made of epoxy resin, urethane resin, polyester resin, vinyl chloride resin or the like on the surface of the metal heat transfer tube 16, the corrosion resistance of the metal heat transfer tube 16 can be improved. Is possible.

Moreover, it is preferable that this resin coating layer contains a heat conductive filler from a viewpoint of improving heat conductivity. Examples of such thermally conductive fillers include boron nitride, aluminum nitride, silicon nitride, silicon carbide, alumina, zirconia, titanium oxide, fine carbon powder, and the like.

In the present invention, a structure in which a single coating layer made of various resins as described above is provided on the surface of the metal heat transfer tube 16 can be employed. First, a corrosion-resistant coating layer made of epoxy resin, urethane resin, polyester resin, vinyl chloride resin, or the like is formed on the surface of the heat transfer tube 16, and a thermoplastic resin such as polyethylene resin is further formed thereon. The structure which forms the resin-made coating-film layer which consists of hydrophilic resin or water-repellent resin is employ | adopted. Further, the thickness of the resin coating layer is preferably 0.1 to 5.0 μm per single layer. If the thickness of the resin coating layer is less than 0.1 μm, the effects of each of the resin coating layers described above may not be enjoyed. On the other hand, a resin coating layer having a thickness exceeding 5.0 μm is provided. However, the effect of each coating layer is already in a saturated state, and it is only costly.

Furthermore, when a resin coating layer made of the above-mentioned resin is provided on the surface of the metal heat transfer tube 16, it is preferable that a base treatment layer is formed on the surface of the metal heat transfer tube 16 in advance. By providing such a base treatment layer, the adhesion between the metal heat transfer tube 16 and each coating layer described above can be improved. Here, as the base treatment layer, chromate treatment using phosphate chromate, chromate chromate, etc., and other than chromium compounds, titanium phosphate, zirconium phosphate, molybdenum phosphate, zinc phosphate, titanium oxide, zirconium oxide Examples thereof include a film layer obtained by chemical film treatment (chemical conversion treatment) such as non-chromate treatment using the like. The chemical film treatment method includes a reaction type and a coating type. In the present invention, any method can be adopted.

In addition, although not listed one by one, the present invention is implemented in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the invention.

Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. It goes without saying.

-Experimental example 1-
First, as a heat transfer tube used to construct a serpentine heat exchanger for an air conditioner according to the present invention, a plurality of inner surface grooves are formed as spiral grooves extending at a predetermined lead angle with respect to the tube axis. An internally grooved heat transfer tube made of acid copper (JIS H3300 C1220) was prepared. The dimensions of the internally grooved heat transfer tube were as follows: outer diameter: 6.35 mm, bottom wall thickness: 0.23 mm, groove depth: 0.15 mm, number of grooves: 58, lead angle: 30 °.

On the other hand, as a fin material, a plate material of 0.13 mm thick pure aluminum (JIS A1050) is prepared, and the surface of the fin material is subjected to a surface treatment consisting of three layers as shown in FIG. did. That is, first, a chemical conversion film 32 made of phosphoric acid chromate was formed on the surface of the aluminum substrate by subjecting the aluminum material substrate 30 to a phosphoric acid chromate dipping treatment. Next, an epoxy resin was applied on the chemical conversion film 32 using a roll coater and heated at a temperature of 220 ° C. for 10 seconds to form a corrosion-resistant coating film 34 having a thickness of 1 μm. And after air cooling, the coating film for hydrophilic coatings which consist of polyvinyl alcohol resin (PVA resin) is apply | coated on the corrosion-resistant coating film 34, and it heats for 10 seconds at the temperature of 220 degreeC, and film thickness is 1.5 micrometers. The fin material having the hydrophilic coating film 36 was formed. Furthermore, as a resin to be applied to the surface of the corrosion-resistant coating film 34, a coating for a water-repellent coating film made of an epoxy resin is used instead of the hydrophilic coating film 36 described above, and this is applied to the surface of the corrosion-resistant coating film 34. It was applied and heated at a temperature of 220 ° C. for 10 seconds to prepare another fin material on which a water-repellent coating film 36 having a film thickness of 1.5 μm was formed.

Then, the two types of fin materials prepared in this way are each cut into a rectangular shape having a size of 12 mm in the x direction and 16 mm in the z direction in FIG. 1, and a heat transfer tube is inserted through the substantially central portion thereof. A large number of two types of fins were prepared by providing through holes (through holes with a 0.5 mm collar on the periphery).

Then, using the heat transfer tubes and fins prepared in this way, a target fin group was formed on one heat transfer tube as follows. That is, a plurality of such fins are arranged so that the respective through holes are parallel to each other with a predetermined interval, and the heat transfer tubes are sequentially inserted through the through holes, and then the heat transfer tubes are expanded. Thus, the heat transfer tubes and the fins were integrated to form a fin group on the heat transfer tubes. At this time, the tube diameter (D) of the heat transfer tube after the tube expansion was 6.75 mm, so that one heat transfer tube penetrated the substantial center of one fin. In addition, by arranging and joining the fins in parallel in order so that the fin interval (fin pitch) and the number of fins are as shown in Table 1 below and joined to the straight pipe portion of the heat transfer tube, all from the same width The target fin group was formed. Examples having fin pitches in the range of 1.0 mm and 3.0 mm according to the present invention are designated as Examples 1 to 4, and those having a fin pitch outside the scope of the present invention are 0.5 to 8 mm as Comparative Examples 1 to 4. It was.

Furthermore, for comparison, a plate material (plate thickness: 0.13 mm) of pure aluminum (JIS A1050) whose surface is not subjected to surface treatment is prepared, and this is processed into fins having the same dimensions as described above. A fin group having the same width as that of the heat transfer tubes similar to those in Examples 1 to 4 and Comparative Examples 1 to 4 was formed. As shown in Table 1 above, the fin pitch and the number of fins of Comparative Example 5 were set to fin pitch: 3.0 mm and the number of fins of 100.

Next, after forming 16 fin groups so formed in the length direction of the heat transfer tubes at a predetermined interval, the heat transfer tube fin groups are subjected to bending processing, The heat transfer tubes are configured to be U-shaped, the fin groups are arranged at a predetermined interval, and the heat transfer tubes are arranged in a meandering form so that the heat transfer tubes sequentially pass through the arranged fin groups. A serpentine heat exchanger as shown in FIG. 1 was produced. In addition, the space | interval (distance between centers) of the heat exchanger tube bent in parallel is 18 mm, and the clearance gap between fins is 1 mm.

Each of the nine types of heat exchangers thus obtained was set in a predetermined outdoor unit as shown in FIG. 2, the refrigerant (R410A) was passed through the heat transfer tube, and the cooling operation by rotating the fan was performed. The presence or absence of water splash was observed. As a result, in the heat exchanger in which the surface treatment was not applied to the fins of Comparative Example 5, the occurrence of water splash was confirmed, and furthermore, in the heat exchangers of Comparative Examples 1 and 3 in which the fin interval was 0.5 mm. Even in such a case, spattering of water was observed even though a hydrophilic resin or water-repellent resin coating layer was provided on the fin surface. On the other hand, in the heat exchangers of Examples 1 to 4 and Comparative Examples 2 and 4 in which the fin interval was 1.0 mm or more, no water splashing was observed at all and a good operation state was confirmed.

Furthermore, for the heat exchangers (total 6 types) in Examples 1 to 4 and Comparative Examples 2 and 4 in which the fin interval is 1.0 mm or more, in order to compare the heat exchange performance, Was done. Specifically, as shown in FIG. 2, in a state where it is set in a predetermined outdoor unit, air is flowed at a constant speed and wind speed with a fan, and all the inlet / outlet conditions on the refrigerant side are constant, and the refrigerant mass flow rate (kg / s ) Was measured. Then, the heat exchange amount (W) was calculated by multiplying the measured refrigerant mass flow rate by the specific enthalpy difference (J / kg) at the refrigerant inlet / outlet.

As a result, in the heat exchangers according to Example 1 and Example 3 in which the fin interval is 1.0 mm, the heat exchange amount thereof is about 1500 W, and the fin interval is 3.0 mm. In each of the heat exchangers of Example 2 and Example 4, both are about 750 W, and therefore, these heat exchangers are heat exchange amounts that can withstand practical use as an air conditioner. Admitted. However, in the heat exchangers of Comparative Example 2 and Comparative Example 4 in which the fin interval is 8 mm, the heat exchange amount is as low as about 100 W, and it was recognized that these are heat exchangers that are difficult to practically use as an air conditioner. .

In the heat exchangers of Examples 1 to 4, when the cross-sectional area defined by the outer diameter of the heat transfer tube and the projected area of the fin are obtained, the cross-sectional area (ST) is 31.7 mm ² , respectively. Since the projected area (SF) is 192 mm ² , the area ratio (SF / ST) is 6.1 times, which is within the appropriate range defined by the present invention (3 to 30 times). It was confirmed that it was preferable from the viewpoint of achieving both miniaturization of the exchanger.

-Experimental example 2-
As a fin material, a plate material of 0.12 mm pure aluminum (JIS A1050) was used, and a film thickness formed on the surface: on a chemical conversion film (undercoat layer) made of 0.1 μm phosphoric acid chromate, Furthermore, while pre-coating a water-repellent coating layer made of a fluorine-based resin, a hydrophilic coating layer made of a polyurethane-based resin, or a water-repellent coating layer made of a silicon-based resin with a thickness of 1 μm, A fin group having a fin interval of 3.0 mm, similar to Experimental Example 1, except that an inner grooved heat transfer tube made of phosphorous deoxidized copper (JIS H3300 C1220) having an outer diameter of 7.00 mm is used. Various serpentine heat exchangers having 16 (number of fins per fin group: 100) arranged were produced.

Next, the various heat exchangers thus obtained were set in a predetermined outdoor unit as shown in FIG. 2 and the cooling operation was performed in the same manner as in Experimental Example 1. I couldn't. Further, the heat exchange amount of these serpentine heat exchangers is as follows: dry bulb temperature: 20 ° C., wet bulb temperature: 15 ° C., overall wind speed: 1.0 m / s, refrigerant: R410A, heat exchanger inlet pressure: 2.3 MPa When measured in the same manner as in Experimental Example 1 under the above conditions, a water-repellent coating layer made of a fluorine-based resin, a hydrophilic coating layer made of a polyurethane-based resin, or a water-repellent coating made of a silicon-based resin was measured on the fin surface. Each of the serpentine heat exchangers with the coating layer formed has a heat exchange amount of about 700 W, about 700 W, or about 720 W, and it is recognized that any of them can be used as an air conditioner. It was.

-Experiment Example 3-
Similar to Example 2 described above, a fin material having a hydrophilic resin coating film formed on the surface and an internally grooved heat transfer tube were prepared, and the fin dimensions were set to 12 mm × 50 mm (fin projection area: 600 mm ² ). A serpentine heat exchanger having a shape as shown in FIG. 5 was prepared in which the number of the heat transfer tubes penetrating into one fin was two. The fin pitch, the number of fins, the number of fin groups, and the like were the same as in the heat exchanger of Example 2. When such a heat exchanger was set in a predetermined outdoor unit in the same manner as the heat exchanger of Example 2, and the presence or absence of water splashing and the heat exchange performance were confirmed, good results were obtained for both. It was confirmed.

-Experimental example 4-
The same fin material (thickness: 0.12 mm) and heat transfer tube (outer diameter: 8.00 mm) as in Example 2 were prepared, and the fin shape was embossed on the fin surface as shown in FIG. As the applied shape, a serpentine heat exchanger having the same surface treatment and dimensions as those of Example 2 was produced. The embossed portion had a height (h): 1.0 mm, a bottom width (d) in a direction perpendicular to the ventilation direction A: 2.8 mm, and a number: 20 pieces.

When the serpentine heat exchanger thus obtained was set in a predetermined outdoor unit as shown in FIG. 2 and cooling operation was carried out, no occurrence of water splash was observed, and the amount of heat exchange Was measured in the same manner as in Experimental Example 2 and was about 800 W. Therefore, by applying such embossing to the fins, when used as an evaporator in a low-temperature environment as an outdoor unit in a cold region, the fins are caused by an appropriate swirl flow generated by such embossed parts, particularly longitudinal vortices. Relatively low temperature air can be prevented from staying near the surface, and relatively high temperature air that tends to stay in the central part between the fins can be brought into contact with the fin surface. It is expected that the effect of suppressing the growth of frosted frost is exhibited.

Moreover, it replaces with formation of the embossing part by this embossing, Serpentine obtained using the fin which provided the cut-and-raised slit (height: 0.7 mm, number: 8 pieces) of planar view by slit processing Similarly, even in the heat exchanger, no water splash was observed, and the heat exchange amount was about 850 W.

-Experimental Example 5-
As the heat transfer tube, an internally grooved heat transfer tube made of pure aluminum (JIS A1050) and having a straight groove on the inner surface was prepared. In such an internally grooved heat transfer tube, the outer diameter was 6.35 mm, the bottom wall thickness was 0.4 mm, the groove depth was 0.15 mm, and the number of grooves was 58. Regarding such an internally grooved heat transfer tube, two types of heat transfer tubes were prepared, one not subjected to surface treatment and the other subjected to zinc spray treatment on the outer surface. Further, as a fin material, a plate material of pure aluminum (JIS A1050) and a plate material of aluminum alloy (JIS A7072) were prepared, and after the surface was subjected to chemical conversion treatment in the same manner as in Example 2 described above, A hydrophilic coating film was formed to obtain a fin material. Further, these two fin materials were processed into the same fin shape as in Example 2.

Using the fins and heat transfer tubes prepared in this way, first, combining the heat transfer tubes made of zinc with the outer surface subjected to zinc spraying and the fins made of pure aluminum (JIS A1050), the fin pitch, the number of fins, etc. A serpentine heat exchanger having the same dimensions as in Example 2 was prepared. On the other hand, a serpentine heat exchanger was similarly produced by combining an aluminum heat transfer tube whose outer surface was not surface-treated and a fin made of an aluminum alloy (JIS A7072). Also in this heat exchanger, the specifications are the same as those in Example 2. By using such a combination of the fin material and the heat transfer tube material, an improvement in the corrosion resistance of the heat transfer tube is expected.

-Experimental Example 6-
As a heat transfer tube, a long straight tubular body made of an Al—Mn-based aluminum alloy (JIS A3003) and having an outer diameter of 7.00 mm and a circular cross section was prepared. Further, as another heat transfer tube, the material and the outer diameter are the same, and an inner surface grooved aluminum alloy tube in which a spiral groove or a straight groove as shown in Experimental Example 1 or Experimental Example 5 is formed as the inner surface groove. Also prepared. Furthermore, a pure aluminum (JIS A1050) plate material having a thickness of 0.12 mm was prepared as a fin material, and a phosphate chromate film and a PVA film or an epoxy resin film were formed on the surface in the same manner as in Experimental Example 1. And each fin was produced.

Next, using the prepared various fins and the various heat transfer tubes, various serpentine heats are combined as shown in Table 2 below, and the fin pitch is 0.5 mm, 1.0 mm, or 3.0 mm. An exchanger was made.

Then, for each of the various serpentine heat exchangers obtained, the cooling operation was performed in the outdoor unit of the air conditioner in the same manner as in Experimental Example 2, and the presence or absence of water splash was observed, and the heat exchange amount was measured. I did it. The results are also shown in Table 2 below.

-Experimental Example 7-
As a heat transfer tube, a tube material made of phosphorous deoxidized copper (JIS H3300 C1220) or an Al—Mn-based aluminum alloy (JIS A3003) and having a smooth inner surface with an outer diameter of 7.00 mm and a circular cross section was prepared. Also, an outer tube surface of such a tube material coated with an epoxy resin or a zinc sprayed coating as in Experimental Example 5 is prepared, and a skin material is provided on the outer peripheral surface of the inner core material layer (JIS A3003). A clad tube (outer diameter: 7.00 mm) having a double tube structure in which layers (JIS A7072) were integrally formed with a clad rate of 7% was also prepared. On the other hand, the fin material was prepared by forming a phosphate chromate film and a PVA film on the surface of a pure aluminum (JIS A1050) plate material having a thickness of 0.12 mm in the same manner as in Experimental Example 1. .

Then, using the prepared various heat transfer tubes and various fins, a serpentine heat exchanger having a fin pitch: 1.0 mm, the number of fins; Made.

The corrosion resistance of the various heat exchangers thus obtained was evaluated by the SWAAT test (ASTM G85-94), and the results are shown in Table 3 below. In the SWAAT test, artificial seawater (pH: 2.8 to 3.0) was used as a test solution, and the temperature was 49 ° C. and the holding atmosphere was 98% RH. Spraying was 30 minutes and holding was 90 minutes. The cycle was repeated.

-Experimental Example 8-
Serpentine heat exchanger No. having a fin group of 16 stages and having various fin pitches of the fin group in the upper region A, the lower region B and the intermediate region thereof. 31-No. 37 was produced in the same manner as in Example 2. In each heat exchanger, the fin group located in the upper stage area A has four stages, and the fin group located in the lower stage area B has four stages, while an intermediate stage between them has an eight-stage fin group. The fin pitches (p ₁ , p ₂ , p ₃ ) of the respective regions are set to have the values shown in Table 4 below in consideration of the wind speed at the respective positions.

Next, heat exchanger no. 31-No. In order to compare the heat exchange performance of 37, the following experiment was conducted. Specifically, in the configuration shown in FIG. 3, with each heat exchanger set in the wind tunnel device, the fan is operated at a predetermined rotational speed to ventilate, while all the inlet / outlet conditions on the refrigerant side are constant. The refrigerant mass flow rate (kg / s) was measured. And the heat exchange amount (W) was calculated by multiplying the measured refrigerant mass flow rate by the specific enthalpy difference (J / kg) at the refrigerant inlet / outlet. In this experiment, heat exchanger No. The wind speed of the upper region A at 31 was 3.0 m / s, the lower region B was 1.0 m / s, and the middle region was 1.5 m / s. In this experiment, the air-side heat transfer area varies depending on the number of fins, and the heat exchanger no. It was calculated as the performance ratio when the value of 31 was 1.0. The results are shown in Table 4 below.

As is apparent from the results in Table 4, the heat exchanger No. No. 31 had a fin pitch of 3.0 mm from the upper region A to the lower region B, and had a heat exchange amount that could withstand practical use as an air conditioner. In addition, heat exchanger No. As for 32, 35 and 36, it is confirmed that the value of p ₂ / p ₁ is in a preferable range specified in the present invention, and the ventilation resistance is not excessive as the whole heat exchanger, and the heat exchange performance is particularly preferable. It was done. Furthermore, heat exchanger No. 33 and 34 are heat exchangers No. Similar to 31, the value of p ₂ / p ₁ is out of the preferred range. Therefore, when appropriate operating conditions are set in the upper fin group, the ventilation resistance increases excessively in the lower fin group, and the air Although it can withstand practical use as a conditioner, the effect of improving the heat exchange performance of the heat exchanger as a whole has not been recognized as sufficient. In addition, heat exchanger No. 37, the value of p ₂ / p ₁ is too large, and the fin pitch (p ₂ ) in the lower region is larger than the appropriate fin pitch, so that the heat exchange performance is low. Is recognized.

DESCRIPTION OF SYMBOLS 10 Heat exchanger 12 Fin 14 Fin group 16 Metal heat exchanger tube 18 Bending part 20 Outdoor unit 22 Fan

Claims

A plurality of fin groups consisting of a plurality of fins arranged in parallel with each other at a predetermined interval in the direction (y direction) perpendicular to the flow direction (x direction) of the heat exchange fluid are the x direction and y A plurality of fin groups are arranged in a line at a certain distance from each other in a direction perpendicular to the direction (z direction), and one or two metal heat transfer tubes are formed in one fin. In the serpentine heat exchanger having a structure in which the metal heat transfer tubes are arranged in a meandering form so as to sequentially penetrate the fin groups of each stage in the form of being penetrated,
The fins constituting the fin group have the same shape, and adjacent fins are arranged at intervals of 0.6 to 5.0 mm,
The fin is composed of a pre-coated metal plate in which a single-layer or multi-layer coating layer is formed on at least one surface of the metal plate, and at least an outermost layer of the coating layer is a hydrophilic resin or a water-repellent It is a coating layer made of resin,
A serpentine heat exchanger for an air conditioner.
The serpentine heat exchanger for an air conditioner according to claim 1, wherein the metal plate is made of aluminum or an aluminum alloy.
The serpentine heat exchanger for an air conditioner according to claim 1 or 2, wherein the heat transfer tube is made of aluminum or an aluminum alloy.
The air according to any one of claims 1 to 3, wherein the heat transfer tube is made of aluminum or an aluminum alloy, and a sacrificial anode effect by zinc is imparted to an outer surface thereof. Serpentine heat exchanger for harmonic machines.
The material of the metal plate is JIS A1050, JIS A1100, JIS A1200, JIS A7072, and JIS A1050, JIS A1100 or JIS A1200, 0.1 to 0.5 mass% of Mn and / or 0.1 to 1.8. Aluminum or aluminum alloy made of any one of those containing Zn of mass%, and the material of the heat transfer tube is any one of JIS A1050, JIS A1100, JIS A1200, and JIS A3003. The serpentine heat exchanger for an air conditioner according to any one of claims 1 to 4, wherein the serpentine heat exchanger is made of aluminum or aluminum alloy composed of seeds.
The serpentine heat exchanger for an air conditioner according to claim 1 or 2, wherein the heat transfer tube is made of copper or a copper alloy.
The material for the heat transfer tube is JIS H3300 C1220 or JIS H3300 C5010. The serpentine heat exchanger for an air conditioner according to claim 6.
Either a straight groove parallel to the tube axis direction, a spiral groove having a predetermined twist angle with respect to the tube axis, or a cross groove configured by a groove intersecting in the tube axis direction on the inner surface of the metal heat transfer tube The serpentine heat exchanger for an air conditioner according to any one of claims 1 to 7, wherein the serpentine heat exchanger has one type or two or more types.
The serpentine heat for an air conditioner according to any one of claims 1 to 8, wherein the fin has a plurality of embossed portions protruding in a thickness direction and having a bottom or outer shape of a circle or an ellipse. Exchanger.
10. The serpentine heat exchanger for an air conditioner according to any one of claims 1 to 9, wherein the fin is subjected to slit processing or louver processing.
The air conditioner according to any one of claims 1 to 10, wherein a projected area of the fin is 3 to 30 times a cross-sectional area defined by an outer diameter of the heat transfer tube. Serpentine heat exchanger.
The serpentine heat exchanger for an air conditioner according to any one of claims 1 to 11, wherein a projected area of the fin is 200 to 1000 mm 2 .
13. The serpentine heat exchanger for an air conditioner according to claim 1, wherein the outer diameter of the metal heat transfer tube is 3 to 13 mm.
The ground treatment layer is provided on the surface of the metal plate, and the single-layer or multiple-layer coating layer is formed on the foundation treatment layer. The serpentine heat exchanger for air conditioners as described.
The hydrophilic resin is selected from the group consisting of a polyvinyl alcohol resin, a polyacrylamide resin, a polyacrylic acid resin, a cellulose resin, and a polyethylene glycol resin. Serpentine heat exchanger for air conditioner as described in 2.
The water-repellent resin is selected from the group consisting of an epoxy resin, a polyurethane resin, an acrylic resin, a melamine resin, a fluorine resin, a silicon resin, and a polyester resin. The serpentine heat exchanger for air conditioners as described in any one.
The serpentine heat exchanger for an air conditioner according to any one of claims 1 to 16, wherein a resin coating layer is formed on a surface of the metal heat transfer tube.
The serpentine heat exchanger for an air conditioner according to claim 17, wherein the resin coating layer contains a heat conductive filler.
An air comprising a serpentine heat exchanger according to any one of claims 1 to 18 and fan means for circulating a heat exchange fluid in the x direction through a plurality of fin groups arranged in the z direction. In the harmony machine,
An interval between adjacent fins in the fin group located in the first region where the wind speed during circulation of the heat exchange fluid by the fan means is large or a part thereof is defined as p 1, and 0 with respect to the wind speed in the first region. a .7 following wind speed, when the interval between adjacent fins in the fin group or a portion thereof located in a small second region of the wind speed was p 2, the following formula:
1.5 ≦ p 2 / p 1 ≦ 3.0
An air conditioner characterized in that the fin interval in the fin group or a part thereof is defined so as to satisfy the above.
The air according to claim 19, wherein the fin group or a part thereof located in the first region and the fin group or a part thereof located in the second region are located at different stages in the z direction. Harmony machine.
The fin group or a part thereof located in the first region and the fin group or a part thereof located in the second region are located in the same step in the z direction. 20. The air conditioner according to 20.