JPH0979692A - Absorbing type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbing type heat exchanger in which a stable and uniform dripping of a circulating liquid can be assured. SOLUTION: After a circulating liquid supplied to a header 12 (14) is discharged out of the header, the liquid is dropped into a tray 32 and once stored in it, and further the liquid passes through a recess 33 and a dripping hole 34 and is dripped toward a heat transfer pipe 13. With such an arrangement as above, a dripping amount of circulating liquid in a longitudinal direction of the heat transfer pipe is made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption heat exchanger used in refrigerators, air conditioners, and the like.

[0002]

2. Description of the Related Art Generally, as a heat exchanger used in a refrigerator or an air conditioner, when a refrigerant is brought into contact with the surface of a heat transfer tube to be vaporized, the latent heat of vaporization causes heat generated by the heat transfer medium to flow in the heat transfer tube. There is known an absorption heat exchanger which is exchanged and is recovered by dissolving the vaporized refrigerant in an absorption liquid.

FIG. 4 is a system diagram of a cooling / heating machine in which this type of absorption heat exchanger is used. The cooling / heating machine indicated by reference numeral 1 in the drawing absorbs the refrigerant (hereinafter referred to as a mixed solution). ) And a condenser 3 for cooling and liquefying the refrigerant separated in the rectifier 2.
And a refrigerant tank 4 for storing the refrigerant liquefied by the condenser 3, a heat exchanger 5 for cooling the absorption liquid separated in the rectifier 2, and the mixed liquid while storing the mixed liquid. To the rectifier 2, a liquid mixture tank 6, an evaporator 7 connected to the refrigerant tank 4, an absorber 8 provided between the heat exchanger 5 and the liquid mixture tank 6, The indoor unit 9 connected to the evaporator 7, the outdoor unit 10 connected to the absorber 8, and the rectifier 2 are provided to heat the mixed liquid sent to the rectifier 2. hand,
A burner 11 for separating the refrigerant and the absorption liquid by utilizing the difference in vaporization temperature is used.

As shown in FIG. 4, the evaporator 7 has a refrigerant header 12 connected to the refrigerant tank 4.
And a heat transfer tube 13 connected to the indoor unit 9, and the absorber 8 is the heat exchanger 5
The absorption type heat exchanger 17 is provided in parallel in a single vacuum container 16 and includes an absorption liquid header 14 connected to the outdoor unit 10 and a heat transfer tube 15 connected to the outdoor unit 10. .

Further, this absorption heat exchanger 17 is provided with a gully-shaped shielding member 18 inside the absorption heat exchanger 17 so as to divide the evaporator 7 and the absorber 8 therein, and only the vaporized refrigerant is removed. The mixed liquid tank 6 is connected to the bottom of the vacuum container 16 while flowing into the absorber 8 side, and the evaporator 7 is provided in a portion located below the evaporator 7. A recovery gutter 19 for collecting the unvaporized refrigerant that is dripped from and returning it to the refrigerant tank 4 is installed.

Further, as shown in FIG. 5, the refrigerant header 12 and the absorbing liquid header 14 have discharge holes 20 on the upper part thereof for dropping the cooling medium and the absorbing liquid at predetermined intervals in the longitudinal direction. A plurality of heat transfer tubes 13 and 15 are formed in parallel with each other in the length direction of the headers 12 and 14 at equal intervals.

In the air conditioner 1 thus constructed, the mixed liquid stored in the mixed liquid tank 6 is sent to the rectifier 2 via the heat exchanger 5 by the pump 21 and heated by the burner 11. As a result, the refrigerant in the mixed liquid is vaporized and separated from the absorbing liquid, and further, the vaporized and separated refrigerant is cooled and condensed in the condenser 3 to be liquefied, and then is transferred to the refrigerant tank 4. Be stored.

The refrigerant in the refrigerant tank 4 is sent to the refrigerant header 12 of the evaporator 7 by the pump 22, and is discharged from the plurality of discharge holes 20 provided in the upper portion of the refrigerant header 12. .

The refrigerant thus discharged flows downward along the outer peripheral surface of the refrigerant header 12, and forms droplets S in the lower portion of the refrigerant header 12 as shown in FIG. When the size of the droplet S grows to a predetermined size, the liquid droplet S is separated from the refrigerant header 12 and drops onto the heat transfer tube 13.

The refrigerant dropped on the heat transfer tube 13 flows down along the surface of the heat transfer tube 13 and is stretched so as to form a thin film on the surface of the heat transfer tube 13 in the process of the flow down. Run down to the bottom of 13,
By the time it reaches the bottom of this heat transfer tube 13, part of it vaporizes,
The remaining refrigerant is collected in the lower part of the heat pipe 13 to form the droplet S.

Such a behavior of the refrigerant is lower than that of the heat transfer tube 13.
Similarly, the refrigerant not vaporized while flowing down the heat transfer pipe 13 at the lowermost end drops from the heat transfer pipe 13 at the lowermost end and the recovery gutter 1
It is recovered by 9 and returned to the refrigerant tank 4.

The heat transfer tubes 13 are heated by the latent heat of vaporization of the refrigerant that is vaporized while the heat transfer tubes 13 flow down.
Is cooled, the heat medium flowing through the heat transfer tube 13 is cooled, and the heat medium is guided to the indoor unit 9 to cool the room.

On the other hand, during the heat exchange in the evaporator 7 described above, in the absorber 8, the absorbing liquid is discharged from the absorbing liquid header 14, and the absorbing liquid also behaves as described above. In the same manner as described above, the absorbent liquid is sequentially dropped into the heat transfer tubes 15 provided below the absorbent header 14, and a thin film of the absorbent is formed on the surface of each heat transfer tube 15.

Here, when the absorbing liquid is made to flow down the heat transfer tube 15, heat exchange is performed with the heat medium flowing in the heat transfer tube 15, whereby the absorbing liquid is cooled and heated. The heat medium is guided to the outdoor unit 10 and its heat is released to the outside air.

In the absorber 8, the evaporator 7 is also provided.
The vaporized refrigerant has flowed in through the shielding member 18, and the refrigerant that has flowed into the absorber 8 comes into contact with the absorbent existing in a thin film on the surfaces of the absorbent header 14 and the heat transfer tube 15. By being made to melt | dissolve, it melt | dissolves in this absorption liquid and is collect | recovered.

The absorbing liquid that has absorbed the refrigerant, that is, the mixed liquid, drops from the heat transfer pipe 15 at the lowermost end to the lower part of the inside of the vacuum container 16, and the mixed liquid tank 6 connected to the bottom of the vacuum container 16. It is supposed to be collected.

[0017]

The conventional absorption heat exchanger 17 as described above, however, has the following problems to be improved.

That is, when the refrigerant is supplied to the evaporator 7, the refrigerant is discharged from a plurality of discharge holes 20 formed in the upper portion of the refrigerant header 12, but the refrigerant header 12 is supplied with the refrigerant. When the refrigerant supply amount or supply pressure fluctuates, the discharge hole 2 is formed at the tip end portion and the base end portion of the refrigerant header 12 due to the flow path resistance of the refrigerant header 12.
This is a problem that the discharge amount at 0 changes. The change in the discharge amount in each discharge hole 20 is
This appears remarkably when the amount of supplied refrigerant is small, such as during bottom load operation in which the capacity of the air conditioner 1 is suppressed.

If the discharge amount of the refrigerant is non-uniform in the length direction of the refrigerant header 12, the formation of a thin film of the refrigerant in the lower heat transfer tube 13 is greatly affected.
The state of vaporization on the surface of these heat transfer tubes 13 becomes unstable, and the heat exchange efficiency thereof decreases, which causes the cooling capacity to decrease.

Such a problem is caused by the absorption liquid header 14 in the absorber 8 and the heat transfer tube 1 provided below the absorption liquid header 14.
The same occurs when the absorbing liquid is supplied to No. 5.

The present invention has been made in view of the above-mentioned conventional problems, and is an absorption type capable of ensuring stable and uniform dripping of circulating fluid regardless of high load operation or bottom load operation. It is an issue to be solved to provide a heat exchanger.

[0022]

In order to solve the above-mentioned problems, the absorption heat exchanger according to claim 1 of the present invention is
A header for supplying a circulating liquid such as a refrigerant or an absorbing liquid is disposed below the header along the length direction thereof, and the circulating liquid is brought into contact with the header to perform heat exchange with the circulating liquid. A heat transfer tube is provided, and between the header and the heat transfer tube, a tray for storing the circulating liquid supplied from the header is provided, and a recess is formed at the bottom of the tray, The bottom of the recess is formed with a dropping hole for dropping the circulating liquid toward the heat transfer tube.

The absorption heat exchanger according to a second aspect of the present invention is the absorption heat exchanger according to the first aspect, wherein the length of the heat transfer tube is at a position facing the drip hole on the surface of the heat transfer tube. The guide groove is formed along the vertical direction.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. In the following embodiments, the configuration other than the main part is the same as the conventional configuration shown in FIGS. 4 and 5, and the common parts are denoted by the same reference numerals and the description thereof is omitted.

FIG. 1 shows an evaporator 31 which constitutes an absorption heat exchanger 30 according to this embodiment.
Is disposed between the refrigerant header 12, the heat transfer tube 13 disposed below the refrigerant header 12, and the refrigerant header 12 and the heat transfer tube 13, and the refrigerant header 1
2 and a tray 32 that stores the refrigerant discharged from the nozzle 2.

The tray 32 is formed in a box shape having an open top and a quadrangular shape in a plan view, and the refrigerant header 12 is provided in the substantially central portion of the inside thereof and the discharge hole 20 thereof is directed upward. It is attached in one.

Further, as shown in FIG. 1, a recess 33 is formed in the bottom of the tray 32, and a drip hole 34 for communicating the inside and outside of the tray 32 is formed in the bottom of the recess 33. Has been done. And this depression 33
As shown in FIG. 2, a plurality of trays are formed at predetermined intervals along the length direction of the tray 32, and are arranged below the refrigerant header 12, respectively, and
It opposes above the heat transfer tube 13.

In the absorption heat exchanger 30 of this embodiment having such a structure, the refrigerant supplied from the refrigerant tank 4 to the refrigerant header 12 by the pump 22 is discharged from the discharge hole 20 of the refrigerant header 12. After that, it is dropped along the surface of the refrigerant header 12 into the tray 32, and is further dropped through the recess 33 and the dropping hole 34 toward the heat transfer tube 13.

Here, in the initial stage of starting the air conditioner 1
By setting the refrigerant supply amount by the pump 22 to be larger than the dropping amount from the dropping hole 34, a predetermined amount of the refrigerant is stored in the tray 32, and after the storing amount reaches a constant value. , By matching the amount of refrigerant supplied by the pump 22 with the amount of drops from the drop holes 34,
The refrigerant level in the tray 32 is kept constant.

The refrigerant dropped into the heat transfer tube 13 is discharged from the refrigerant header 12 and then temporarily stored in the tray 32 and then dropped into the heat transfer tube 13. The amount of refrigerant discharged from
Even if it becomes non-uniform in the length direction, the fluctuation is absorbed by the refrigerant stored in the tray 32, so that the amount of drops from the respective drop holes 34 is made uniform.

Moreover, the refrigerant is transferred from the tray 32 to the heat transfer tube 13
When it is dripped into, since it is once introduced into each recess 33 and then guided to the drop hole 34, the refrigerant located in the recess 33 and the refrigerant stored above it are partitioned, Even if the refrigerant in the tray 32 sways such as wavy, its influence is suppressed from acting on the inside of the recess 33, and the volume of the recess 33 and the drip hole 3 are suppressed.
Since the amount of the refrigerant dropped from the dropping hole 34 is regulated by the opening area and the length of 4, the synergistic action of these refrigerants makes the dropping amount of the refrigerant from the dropping holes 34 uniform.

Since the drip hole 34 of the depression 33 is installed so as to be located at the center of the heat transfer tube 13 in the vertical direction, the drip solution flows symmetrically from the center of the heat transfer tube 13 to form a more uniform liquid film.

Here, a suitable example of the dimensions of the recess 33 and the dropping hole 34 will be shown. Although it varies depending on the kind of the refrigerant, for example, when TFE (trifluoroethanol) is used as the refrigerant (in this case, TFE (trifluoroethanol) is used). , Normal methylpyrrolidone is used as the absorber), the inner surface shape of the recess 33 is a spherical shell having a radius of 5 mm, and the diameter of the dropping hole 34 is 0.8 mm to 1.0 mm.

Therefore, in this embodiment, even when the refrigerant supply in the refrigerant header 12 fluctuates, or even in the low load operation in which the refrigerant supply amount is small,
The amount of the refrigerant dropped onto the heat transfer tube 13 is ensured by the tray 32, and is made uniform in the length direction,
As a result, a uniform thin film of the refrigerant is formed over the entire length of the heat transfer tube 13, and the refrigerant is uniformly vaporized at various points of the heat transfer tube 13, so that a good heat exchange action is obtained.

In the above-described first embodiment, the refrigerant is exemplified as the circulating liquid, and the refrigerant header 12 is exemplified as the header for supplying the circulating liquid. Of course, it can be applied to the vessel 8, and can be applied to both the evaporator 31 and the absorber 8.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a second embodiment of the present invention will be described with reference to FIG. Similar to the first embodiment described above, the present embodiment is applied to the evaporator 41 that constitutes the absorption heat exchanger 40, and the heat transfer tube 13 in the first embodiment is improved. Is.

That is, in the heat transfer tube according to the present embodiment shown by reference numeral 42 in FIG. 3, the guide groove 43 along the length direction is formed in the portion located above the heat transfer tube, and the heat transfer tube is placed at the uppermost position. The guide groove 43 of the heat transfer tube 42 is
It is configured to face each of the dropping holes 34.

In the present embodiment having such a configuration, the refrigerant discharged through the refrigerant header 12 is
Similar to the first embodiment, after being once stored in the tray 32, it is evenly dropped to the heat transfer tube 42 via the recesses 33 and the dropping holes 34 formed in the tray 32. Further, in the present embodiment, after the refrigerant dropped from above is dropped into the heat transfer tube 42 below, the length of the heat transfer tube 42 is changed by the guide groove 43 formed in the heat transfer tube 42. It is guided and stored in the same direction.

After the guide groove 43 is filled with the refrigerant, the refrigerant overflows the surface of the heat transfer tube 42 so that the refrigerant flows in the guide groove 43. It overflows almost uniformly over the entire length in the length direction, whereby each heat transfer pipe 42
The flow of the refrigerant on the surface of the heat transfer tubes is made uniform, and the thin film of the refrigerant formed on the surface of each heat transfer tube 42 is made more uniform.

Therefore, in this embodiment, the amount of the refrigerant dropped from the refrigerant header 12 to the heat transfer tube 42 is made uniform in the lengthwise direction, and the heat transfer tube 42 is also added.
Even after being dropped, the homogenization is promoted.

As a result, a more uniform refrigerant thin film can be formed on the surface of the heat transfer tube 42, and a thinner thin film can be formed. When applied to the evaporator 41 as described above, its heat exchange efficiency is improved. When improved or applied to the absorber 8, a thin film of the absorbing liquid is reliably formed, and the thin film is formed to be thin, whereby the absorbing liquid is efficiently cooled, and Dissolution of the refrigerant into the absorbing liquid is favorably performed.

The shapes and sizes of the constituent members shown in the above-described embodiments are merely examples, and can be variously changed according to the type of equipment to be applied, the type of refrigerant or absorbing liquid to be used, and the like. Is.

[0043]

As described above, according to the first aspect of the present invention.
According to the absorption heat exchanger of the present invention, when the circulating liquid supplied from the header is temporarily stored by the tray provided below the circulating liquid, there is a fluctuation in the circulating liquid supply in the header, or Even during low load operation where the circulating fluid supply amount is small, the amount of the circulating fluid dropped into the heat transfer tube is secured by the tray, and it is made uniform in the lengthwise direction. As a result, a uniform thin film of the circulating liquid can be formed, and a good heat exchange action can be obtained at various points of the heat transfer tube.

Therefore, in the evaporator which constitutes the absorption heat exchanger, the refrigerant is vaporized well, and in the absorber which is another component, the absorption liquid is cooled and the refrigerant is well absorbed. As a result, the function of the absorption heat exchanger can be enhanced.

Further, according to the absorption type heat exchanger of the second aspect of the present invention, in addition to the function and effect of the first aspect, the circulating liquid dropped in the heat transfer tube is formed in the heat transfer tube. By guiding the heat transfer tube in the lengthwise direction, the circulating liquid can be uniformly supplied to the surface of the heat transfer tube over the entire length thereof, whereby the circulation in the lengthwise direction of the heat transfer tube is achieved. The liquid flow can be made more uniform, and the function of the absorption heat exchanger can be further enhanced.

[Brief description of drawings]

FIG. 1 shows a first embodiment of the present invention and is a vertical cross-sectional view showing a main part of an evaporator constituting an absorption heat exchanger.

FIG. 2 shows the first embodiment of the present invention and is an external perspective view showing a main part of the tray.

FIG. 3 shows a second embodiment of the present invention, and is a vertical cross-sectional view showing a main part of an evaporator constituting an absorption heat exchanger.

FIG. 4 is a system configuration diagram of a cooling / heating machine to which a conventional absorption heat exchanger is applied.

FIG. 5 is a vertical cross-sectional view showing a main part of an evaporator that constitutes a conventional absorption heat exchanger.

[Explanation of symbols]

 8 Absorber 12 Refrigerant Header (Header) 13 Heat Transfer Tube 14 Absorption Liquid Header 15/42 Heat Transfer Tube 16 Vacuum Container 18 Shielding Member 20 Discharge Hole 30/40 Absorption Type Heat Exchanger 31/41 Evaporator (Absorption Type Heat Exchanger) 32 tray 43 guide groove

Claims (2)

[Claims] 1. A header for supplying a circulating liquid such as a refrigerant or an absorbing liquid, and a header disposed below the header along the length direction thereof to bring the circulating liquid into contact with the circulating liquid. A heat transfer tube for performing heat exchange, and a tray for storing the circulating liquid supplied from the header is provided between the header and the heat transfer tube, and a recess is formed at the bottom of the tray. In addition, the absorption heat exchanger is characterized in that a drip hole for dropping the circulating liquid toward the heat transfer tube is formed at the bottom of the recess. 2. An induction groove is formed along the length direction of the heat transfer tube at a position facing the drip hole on the surface of the heat transfer tube. Absorption heat exchanger.