JP3240548B2 - Absorption refrigerator and its heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerator having a bellows fin in a heat exchanger such as an evaporator and a condenser, and a heat exchanger thereof.

[0002]

2. Description of the Related Art Conventional absorption refrigerators are widely used as air conditioners and the like. An outline of an example of an absorption refrigerator will be described with reference to FIG. The high-temperature regenerator 21 contains a combustion chamber therein, heats the diluted solution having a reduced concentration by absorbing the refrigerant, and generates refrigerant vapor from the diluted solution. The separator 22 separates the refrigerant vapor from the intermediate concentrated solution whose concentration has been increased by generating the refrigerant vapor, and sends the former to the high-temperature solution heat exchanger 27 and the latter to the low-temperature regenerator 23.
The low-temperature regenerator 23 reheats the intermediate concentrated solution whose temperature has been lowered by the high-temperature solution heat exchanger 27 with the refrigerant vapor coming from the separator 22, and further generates refrigerant vapor from the intermediate concentrated solution. And the intermediate concentrated solution itself is made into a concentrated solution, and a part of the refrigerant vapor coming from the separator 22 is condensed and made into a refrigerant liquid and sent to the condenser 24. The condenser 24 cools and liquefies the refrigerant vapor generated in the low-temperature regenerator 23 and the refrigerant vapor not converted into the refrigerant liquid in the low-temperature regenerator 23 by using cooling water, converts the refrigerant vapor into a refrigerant liquid, and sends the refrigerant liquid to the evaporator 25. The evaporator 25 is a heat transfer tube (cooler) 25 into which circulating water to be cooled flows.
A is provided, the refrigerant liquid sent from the condenser 24 is sprayed to the heat transfer tube 25A using the sprayer 25B, and the circulating water is cooled by utilizing heat of vaporization when the refrigerant liquid becomes refrigerant vapor. And make it cold water. The concentrated solution that has passed through the low-temperature solution heat exchanger 28 from the low-temperature regenerator 23 is introduced into the absorber 26, and is sprayed and dropped using the sprayer 26B provided at the top. The concentrated solution is vaporized in the evaporator 25. The absorbed refrigerant vapor is absorbed. A high vacuum is secured in the evaporator 25 by the absorption function of the absorber 26, and the refrigerant liquid sprayed on the heat transfer tube 25A in the evaporator 25 can be immediately evaporated.

The absorber 26 has a cooling means 26A for cooling when the concentrated solution absorbs the refrigerant vapor and becomes a dilute solution.
Are arranged. The cooling means 26A is formed of a coiled pipe or a bellows fin, is connected to the cooling means 24A in the condenser 24, and circulates cooling water inside. The hot solution heat exchanger 27 exchanges heat between the hot intermediate concentrated solution and the cold dilute solution,
The low-temperature solution heat exchanger 28 performs heat exchange between a high-temperature concentrated solution and a low-temperature dilute solution, and is provided in two stages on a high-temperature side and a low-temperature side to improve heat exchange efficiency. The solution circulation pump 29 absorbs the refrigerant vapor in the absorber 26 to form a dilute solution, and converts the diluted solution into a low-temperature solution heat exchanger 28 and a high-temperature solution heat exchanger 2.
It is provided for sending to the high temperature regenerator 21 through 7 and circulating again. Reference numeral 30 denotes a cooling / heating switching valve. The cooling / heating switching valve 30 is provided in the middle of the pipe between the separator 22 and the evaporator 25 and the absorber 26. Is introduced directly into the evaporator 25 via the separator 22 and heat exchanges with circulating water in a heat transfer tube (water heater) 25A to obtain hot water.

[0004] The bellows fins are connected to an absorption refrigerator such as an evaporator 25, an absorber 26, a condenser 24, and a low-temperature regenerator 2.
3 and so on. The present applicant has disclosed an absorption refrigerator having a bellows fin in a heat exchanger as disclosed in Japanese Patent Application No. Hei.
Japanese Patent Application No. 3-52559 proposes an absorption refrigerator in which a bellows fin and a predetermined net are provided in a heat exchanger. An outline of the structure of the bellows fins and the net of such an absorption refrigerator will be described with reference to FIGS. Circulating water (cold water) flows into the one closed chamber 36 formed by the side plate 31 and the bellows fins 32 from the cold water inlet 33 and flows out from the cold water outlet 34. On the other hand, the other room 3
The refrigerant liquid 35 is dropped on 7, and cools the circulating water using heat of vaporization when the refrigerant liquid 35 becomes refrigerant vapor. By making the heat transfer surface a bellows fin, the area where the cooling water, the solution, or the like that performs heat exchange comes into contact with the heat transfer surface is increased, and the heat exchange rate can be improved. In this case, it is necessary to improve the wettability of the bellows fins 32 in order to improve the heat transfer performance, and the wettability of a heat exchanger such as the evaporator 25 is further increased by providing a net. Evaporator 25 shown in 6
It is. The evaporator 25 has a chamber 37 loaded with a net 38 as shown by an arrow B in FIG. By loading the net 38, the wetting and spreading property of the refrigerant liquid in the direction perpendicular to the flowing direction (the direction of arrow C) is improved, the heat transfer efficiency is improved, and the heat exchange rate between the cold water and the refrigerant liquid is further improved. .

On the other hand, the surface roughness of the heat transfer surface can be increased by sandblasting to improve the wettability, or the surface roughness can be increased by knurling by rolling as shown in FIG. However, when the net 38 is brazed to the bellows fin 32, the brazing material is
8, there is a possibility that the refrigerant liquid will not be diffused.

[0006]

In a conventional absorption refrigerator, in order to improve the heat exchange rate by loading a net on the bellows fins of the heat exchanger, the degree of adhesion between the heat transfer surface of the bellows fins and the net is increased. Importantly, when the bellows fins and the net are adhered by brazing, the brazing material enters into the gap of the net, so that an effective shape for diffusing the refrigerant liquid by the capillary phenomenon cannot be obtained. Also, it has been difficult to realize cost reduction. Furthermore, the thickness of the material to be processed by sand blasting and knurling is required to some extent, and it is not possible to sufficiently reduce the thickness of the bellows fin.In that respect, it is necessary to increase the heat exchange rate between the cold water and the refrigerant liquid. Can not. When grooves are formed directly on the heat transfer surface by etching, a groove shape effective for wetting can be obtained. However, since etching is a technique generally used for decoration of building materials, it is difficult to reduce cost because it is expensive. there were.

It is an object of the present invention to provide an absorption refrigerator having a heat exchanger which realizes low cost and has a high heat exchange rate between cold water and a refrigerant liquid and a heat exchanger thereof.

[0008]

In order to achieve the above object, an absorption refrigerator according to the present invention comprises a high-temperature regenerator for heating a dilute solution with a heating source, and a refrigerant for heating the solution heated by the high-temperature regenerator. A separator that separates into a vapor and an intermediate concentrated solution, a high-temperature solution heat exchanger that heat-exchanges the intermediate concentrated solution from the separator with a dilute solution, and an intermediate concentrated solution whose temperature is reduced by the high-temperature solution heat exchanger from the separator A low-temperature regenerator that reheats with the coming refrigerant vapor to further generate refrigerant vapor from the intermediate concentrated solution and makes it a concentrated solution; The evaporator sprays the refrigerant liquid from the cooler to the cooler to obtain cold water from the cooler, and the concentrated solution that exchanges heat from the low-temperature regenerator through the low-temperature solution heat exchanger is sprayed and vaporized by the evaporator. An absorber for absorbing refrigerant vapor;
A solution circulation pump that sends the dilute solution that has absorbed the refrigerant in the absorber to the high-temperature regenerator via the low-temperature solution heat exchanger and the high-temperature solution heat exchanger, and has at least one of the evaporator and the absorber. in the absorption refrigerating machine provided with bellows fins processed waveform shape by bending continuous sheet, the bellows fins have a heat transfer surface formed by joining the wire mesh, wire mesh
Is the end face of the side of this wire mesh that is joined to the heat transfer surface
Only at the joints,
The contact angle with the heat transfer surface is 90 ° or less .

With this configuration, the heat transfer surface flows down.
Solution and refrigerant along the gap between the heat transfer surface and the wire mesh.
Spreads and spreads at right angles to the downflow direction, wide heat transfer surface
Since the solution or refrigerant flows down in the range, the wettability of the heat transfer surface is improved.
In addition, the heat exchange rate can be made higher than before.

Further, the end face of each wire of the wire mesh and the heat transfer surface are burned.
Are joined together, and this joined part is alloyed.
And to that configuration.

With this configuration, each wire of the wire mesh is
Since the joint between the end face and the heat transfer surface is alloyed, heat transfer
This means that the area has increased, and the heat exchange rate has
Can be higher.

Further, the flow path of the first fluid and the flow path of the second fluid
The flow path and the bellows fins are formed, and the transmission of the bellows fins is performed.
Heat exchange between the first fluid and the second fluid via the hot surface
In heat exchangers for absorption refrigerators, a wire mesh is
This wire mesh is joined and the heat transfer of each wire of this wire mesh
Each mesh line at the end face that is in contact with the surface
The heat transfer surface has a contact angle of 90 ° or less.
It is a heat exchanger for refrigerators.

[0013]

1 and 2 show an embodiment of the present invention.
This will be described with reference to FIG. As shown in FIGS. 1 and 2,
A high-temperature regenerator 21 for heating the dilute solution with a heating source, a separator 22 for separating the solution heated by the high-temperature regenerator 21 into a refrigerant vapor and an intermediate concentrated solution, and the intermediate concentrated solution from the separator 22 as a dilute solution. The high-temperature solution heat exchanger 27 for heat exchange, and the intermediate concentrated solution whose temperature has been lowered by the high-temperature solution heat exchanger 27 are reheated with refrigerant vapor coming from the separator 22 to further generate refrigerant vapor from the intermediate concentrated solution and concentrate. Low temperature regenerator 23 as a solution
A condenser 24 that cools and liquefies the refrigerant vapor generated in the low-temperature regenerator 23 into a refrigerant liquid; a evaporator 4 that scatters the refrigerant liquid from the condenser 24 to the cooler to obtain cold water from the cooler; An absorber 26 that absorbs the refrigerant vapor vaporized by the evaporator 4 by spraying a concentrated solution that exchanges heat from the low-temperature regenerator 23 through the low-temperature solution heat exchanger 28, and a rare medium that absorbs the refrigerant by the absorber 26. A solution circulation pump 29 for sending the solution to the high-temperature regenerator 21 via the low-temperature solution heat exchanger 28 and the high-temperature solution heat exchanger 27; and at least one of the evaporator 4, the absorber 26 and the low-temperature regenerator 23. One is an absorption refrigerator including a corrugated bellows fin 1 formed by continuous bending of a thin plate. The bellows fin 1 has a heat transfer surface 2 formed by bonding a wire mesh 3. . The heat transfer surface 2 is made of stainless steel, and the end face of each wire 3a of the wire mesh 3 and the heat transfer surface 2 are joined at least by sintering, and each wire 3a is a joining point 3b and is 90 ° or less. It is assumed that it is in contact with heat transfer surface 2 at contact angle α.

That is, in the present embodiment, a bellows fin provided in an evaporator among heat exchangers of an absorption refrigerator is shown.
A wire mesh 3 is joined to a heat transfer surface 2 of a corrugated bellows fin 1 formed by continuous bending of a thin plate by sintering or the like.
The heat transfer surface 2 of the bellows fin 1 is formed of a stainless steel plate having a plate thickness of 1 mm or less, and the wire mesh 3 has a wire diameter of Φ0.1 to Φ.
Mesh 150-1 with mesh wire 3a of 1.0 stainless steel etc.
0, and the heat transfer surface 2 and the end face of each wire 3a of the wire mesh 3 are joined at the joining point 3b and are completely alloyed.
The gap 3c between the heat transfer surface 2 and the mesh wire 3a is held as it is.

In the joining by sintering, first, the heat transfer surface and the wire mesh are brought into close contact with each other, and both are pressed with a jig usually at about 1 kg / cm ² . Then, in a vacuum furnace or reduction furnace, 12
By heating at about 50 ° C., holding for 1 to 2 hours, and then quenching, the contact portion is diffused at the molecular level and alloyed to complete. FIG. 2 shows the joining by sintering, but other joining means may be used, such as laser joining.

When the refrigerant liquid is sprayed on the heat transfer surface formed by joining the wire nets, the contact angle between each wire of the wire mesh and the heat transfer surface on the heat transfer surface is 90 ° or less. The refrigerant liquid is held in the gaps of the wire mesh and is diffused along the gaps by capillary action. Therefore, the entire heat transfer surface is effectively used, and the heat transfer efficiency is improved. In addition, the end face of the wire mesh of the wire mesh is joined to the heat transfer surface and is completely alloyed, so that the heat transfer area is increased.

Next, as another embodiment of the present invention, a heat exchanger for an absorption refrigerator will be described with reference to FIGS. 3 and 4. FIG. 3 is a partially cutaway side view of the evaporator 4 as an example, and FIG. 4 is a cross-sectional view of the evaporator 4 shown in FIG. The flow path 6 for the first fluid and the flow path 9 for the second fluid are formed by the bellows fin 1, and heat exchange between the first fluid and the second fluid via the heat transfer surface 2 of the bellows fin 1. A heat exchanger for an absorption type refrigerator, as shown in FIG.
Is made of stainless steel and has a configuration in which the wire mesh 3 is joined at least by sintering. And wire mesh 3
It is assumed that each mesh wire 3a is in contact with the heat transfer surface at a junction point 3b with the heat transfer surface 2 at a contact angle α of 90 ° or less.

The heat transfer surface 2 to which the wire mesh 3 is joined faces the chamber 9,
The other heat transfer surface 2 faces the chamber 6. In the evaporator 4, circulating water (cold water) as a first fluid is supplied from a cold water inlet 7 to one chamber 6, which is a sealed first fluid flow path formed by the side plate 5 and the bellows fin 1. ) Flows in and flows out from the cold water outlet 8. On the other hand, the refrigerant liquid 10 as the second fluid is dropped into the other chamber 9 which is the flow path of the second fluid, and cools the cold water using heat of vaporization when the refrigerant liquid 10 becomes refrigerant vapor. .
The refrigerant liquid 10 flowing through the heat transfer surface 2 is held in a gap 3c between the heat transfer surface 2 and the wire mesh 3, diffuses along the gap 3c by capillary action, and flows down while wetting the heat transfer surfaces 2 on both sides. Note that the present invention is not limited to the above embodiment, and the wire netting 3 may face any of the chambers 6 and 9.

According to this embodiment, since the wire mesh is joined to the heat transfer surface, the area of the heat transfer surface is larger than that of the conventional bellows fin.
In addition, the refrigerant liquid held in the gap between the heat transfer surface and the wire mesh,
The heat transfer surface of both sides flows down while wetting the heat transfer surfaces on both sides while diffusing by capillary action, so that the heat transfer surface has improved wettability and a higher heat exchange rate than conventional bellows fins.

Further, when the bellows fins are formed by sandblasting or knurling, the thickness of the material is required to some extent, and the bellows fins cannot be made sufficiently thin. Since the heat exchange rate of the bellows fin of the present embodiment is reduced to 1 mm or less,
It is easily formed by pressing or drawing, and reduces the thermal resistance, thereby increasing the heat exchange rate.

In addition, in a heat exchanger such as an evaporator or an absorber of an absorption refrigerator, corrosiveness due to a circulating solution or the like often becomes a problem, and stainless steel is used as a material for the bellows fin in consideration of this point. Although it is used, it has poor heat conductivity and does not increase the heat exchange rate as compared with the case where copper is used as a material. However, even in the case of using a bellows fin made of stainless steel, by providing a heat exchanger in which a wire mesh is joined to the heat transfer surface, it is possible to provide an absorption refrigerator that is resistant to corrosion and has a high heat exchange rate. it can.

[0022]

According to the present invention, at least one of the evaporator and the absorber has a wire mesh joined to the heat transfer surface of the bellows fin, so that the area of the heat transfer surface is increased, and The refrigerant liquid held in the gap between the heat transfer surface and the wire mesh diffuses and flows while wetting the heat transfer surfaces on both sides, so that the wettability of the heat transfer surfaces is improved and the heat exchange rate is increased. Furthermore, since the bellows fins have a reduced thickness, they can be easily formed by pressing or drawing. The heat resistance is reduced, the heat exchange rate is increased, and the processing cost is reduced. It is possible to reduce the cost while maintaining high values.

[Brief description of the drawings]

FIG. 1 is a system diagram of an absorption refrigerator showing one embodiment of the present invention.

FIG. 2 is a view showing the shape of a bellows fin used in the heat exchanger of FIG.

FIG. 3 is a partial sectional view of an evaporator using the bellows fin shown in FIG. 2;

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

FIG. 5 is a system diagram of an absorption refrigerator showing a conventional technique.

FIG. 6 is a partial sectional view of an evaporator showing a conventional technique.

FIG. 7 is a sectional view taken along line DD in FIG. 6;

FIG. 8 is a view showing a heat transfer surface of a conventional bellows fin.

FIG. 9 is a view for explaining the operation of a conventional bellows fin.

[Explanation of symbols]

 1 bellows fins 2 heat transfer surface 3 wire mesh

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-2989 (JP, A) JP-A-49-52175 (JP, A) JP-A-61-105097 (JP, A) 69568 (JP, U) Japanese Utility Model Hei 5-45473 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F28F 1/00-1/44 F25B 39/02 F25B 37/00

Claims (3)

(57) [Claims] 1. A high-temperature regenerator for heating a dilute solution with a heating source, a separator for separating the solution heated by the high-temperature regenerator into a refrigerant vapor and an intermediate concentrated solution, and separating the intermediate concentrated solution from the separator. A high-temperature solution heat exchanger that exchanges heat with the dilute solution, and an intermediate concentrated solution whose temperature has been reduced by the high-temperature solution heat exchanger is reheated with refrigerant vapor coming from the separator to generate additional refrigerant vapor from the intermediate concentrated solution. A low-temperature regenerator that makes a concentrated solution, a condenser that cools and liquefies the refrigerant vapor generated in the low-temperature regenerator to make a refrigerant liquid, and sprays the refrigerant liquid from the condenser to the cooler to cool water from the cooler. An evaporator, an absorber that absorbs the refrigerant vapor vaporized in the evaporator, in which a concentrated solution that performs heat exchange from the low-temperature regenerator through the low-temperature solution heat exchanger is dispersed, and a refrigerant in the absorber. The diluted solution absorbed into the low temperature solution heat exchanger and the high temperature A solution circulating pump that sends the solution to the high-temperature regenerator via a solution heat exchanger, and at least one of the evaporator and the absorber has a corrugated bellows fin processed by continuous bending of a thin plate. in the absorption refrigerating machine provided with the bellows fins have a heat transfer surface formed by joining the wire mesh, the wire mesh, the mesh lines of the gold network
Is joined only at the end face of the side to be joined to the heat transfer surface.
Contact between each of the mesh wires and the heat transfer surface at the joined portion.
An absorption refrigerator having an angle of 90 ° or less . Wherein end faces of the mesh lines of the wire mesh and said heat transfer surface
There are bonded by sintering, the junction portion is an alloy
Absorption chiller according to claim 1, characterized in that turned into. 3. A flow path for the first fluid and a flow path for the second fluid are formed by bellows fins, and the first fluid and the second fluid are connected to each other via a heat transfer surface of the bellows fins. In a heat exchanger for an absorption type refrigerator for exchanging heat, a wire mesh is joined to the heat transfer surface, and the wire mesh is formed of each wire of the wire mesh.
Each mesh wire is joined to the heat transfer surface at the end face that contacts the heat transfer surface
A heat exchanger for an absorption refrigerator, wherein the heat exchanger is in contact with the heat transfer surface at a contact angle of 90 ° or less .