JP3756980B2 - Plate type absorber for absorption refrigerator - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a plate-type absorber used for an absorption refrigerator.
[0002]
[Prior art]
FIG. 1 is a system diagram for explaining the principle of the absorption refrigerator 1. In the regenerator 2, the rare absorbent 3 is heated by a heating source, for example, city gas, and the refrigerant vapor is separated to obtain a concentrated absorbent. The refrigerant vapor is cooled and condensed by the condenser 4 to become a refrigerant liquid 5. The refrigerant liquid 5 is depressurized by the pressure reducing valve 6, the liquid to be cooled, for example, water is cooled by the evaporator 7, and the refrigerant liquid itself evaporates. In order to keep the evaporator 7 at a reduced pressure and promote the evaporation of the refrigerant liquid, the refrigerant vapor is absorbed by the absorber 8 with the concentrated absorbent from the regenerator 2. The concentrated absorbent absorbs the refrigerant vapor to become the rare absorbent 9, is pressurized by the solution pump 10, and is sent to the regenerator 2 through the heat exchanger 11. The concentrated absorbent 3 from the regenerator 2 is depressurized by the pressure reducing valve 12 and sent to the absorber 8 through the heat exchanger 11. Since the absorbing liquid generates heat when absorbing the refrigerant vapor, the absorber 8 is cooled with cooling water. The evaporator 7 is provided with a refrigerant pump 11 to circulate the non-evaporated refrigerant liquid 12.
[0003]
In a typical absorber of the prior art, the absorbing liquid is sprayed from the top, a horizontal multi-tube type cooling water pipe is provided below, and the refrigerant liquid is absorbed while dripping the outside of the cooling water pipe. It is. In this type of absorber, the cooling water pipes must be densely provided in order to increase the heat transfer area, and therefore, it is necessary to narrow the interval between the cooling water pipes. On the other hand, the refrigerant vapor from the evaporator flows between the cooling water pipes. The flow rate of the refrigerant vapor is the largest near the evaporator, and generally exceeds 50 m / s, the resistance increases and the performance of the absorber decreases. Therefore, the interval between the cooling water pipes is generally designed so that the steam flow rate does not exceed 50 m / s. Therefore, the number of cooling water pipes per unit cross-sectional area is limited, and the absorber cannot be made compact. is there.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a plate type absorber having a high absorption efficiency and being used for an absorption refrigerator.
[0005]
[Means for Solving the Problems]
The present invention relates to a regenerator for separating a refrigerant vapor from a diluted absorbent to obtain a concentrated absorbent, a condenser for cooling the refrigerant vapor to obtain a refrigerant liquid, evaporating the refrigerant liquid under reduced pressure, and a liquid to be cooled. An absorption refrigeration system that includes an evaporator that cools the refrigerant and an absorber that absorbs refrigerant vapor generated in the evaporator with a concentrated absorbent, and circulates the absorbent through a heat exchanger between the regenerator and the absorber In the machine
Consists of two vertical corrugated plates with wavy irregularities horizontally and closed on both sides,
An absorption liquid dispersion tray is provided at the top, and the absorption liquid flows down from the absorption liquid dispersion tray along the outer surface of the two corrugated plates,
Cooling water is supplied from the lower part on one side, and discharged from the upper part on the other side, between the two corrugated plates .
A plate-type absorber for an absorption refrigerating machine, wherein the two corrugated plates are combined so that the concave portions and the convex portions face each other, and a core material is disposed in the cooling water passage .
According to the present invention, a plate-type absorber having two corrugated plates having horizontally wavy irregularities and closed on both sides can be used so that the plate can be parallel to the flow direction of the refrigerant vapor. The flow velocity at the absorber inlet of the refrigerant vapor passage is constant at any part, and if this flow velocity is designed to be 50 m / s, the plate interval (distance between adjacent plate type absorbers) can be reduced to about 14 mm. In addition, since the outer shape of the plate is horizontal, the heat transfer area can be increased by 20 to 30% compared to a flat plate having the same length and width. As a result, the size can be reduced to about a half of that of a conventional horizontal tube type absorber.
[0006]
Further , since the two corrugated plates are opposed to each other and the convex portions are opposed to each other, and the core material is disposed inside, the turbulent flow can be caused in the flow of the cooling water to improve the heat transfer performance. The core material also acts as a reinforcing material and withstands a large pressure difference between the inner and outer surfaces of the absorber (for example, an outer surface of 0.01 atm and an inner surface of 6 to 8 atm).
[0007]
Further, the invention is characterized in that the absorbing liquid dispersion tray has a bowl shape, and a large number of slits are provided in the upper and lower directions at equal intervals on the upper sides of both sides.
According to the present invention, the absorbing liquid dispersion method is a bowl-shaped tray, and a large number of slits are provided at equal intervals in the upper part of both side surfaces. Since the absorbing liquid is supplied to the bowl-shaped tray, the absorbing liquid flows down uniformly from the slit to the outer surface of the corrugated plate, and the refrigerant vapor is efficiently absorbed. Further, the absorption liquid is prevented from flowing out to the evaporator side as compared with the case where the absorption liquid is jetted from the upper part of the absorber as in the prior art.
[0008]
In the invention, it is preferable that the corrugated plate has a pitch of 2 to 5 mm, a wave depth of 0.5 to 2 mm, and a convex bending radius of 0.2 to 2 mm.
In accordance with the present invention, the preferred shape of the corrugated sheet is shown. This shape was obtained by the present inventors as a result of experiments, and maintains high absorption efficiency and is easy to process. In this shape, the absorbing liquid does not detach from the outer surface of the corrugated plate, the entire outer surface is wetted, and the Marangoni convection caused by the concentration difference when the absorbing liquid absorbs the refrigerant vapor is not hindered. For this reason, a heat transmissivity improves to 2000-2500 kcal / m < ² > h (degreeC) (The heat transmissivity of the conventional horizontal multi-tube type is about 1500 kcal / m < ² > h (degreeC)).
[0009]
In the invention, the absorbent dispersion tray is provided with 0.5 to 1.5 mm slits at intervals of 5 to 20 mm.
According to the present invention, the preferred shape of the absorbent dispersion tray is shown. This shape was obtained by the present inventors as a result of experiments, and in this range, the absorbing liquid flows down on the outer surface of the corrugated plate evenly in the horizontal direction.
The material of the absorber is not particularly limited in the present invention, but is preferably made of a metal having high thermal conductivity, and is preferably made of copper like a horizontal multitubular cooling pipe.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described more specifically with reference to embodiments. The structure of the absorption refrigerator is the same as that described in the prior art based on FIG.
[0011]
2 is a front view of the plate-type absorber 21 of the present invention, FIG. 3 is a plan view, and FIG. 4 is a partially enlarged sectional view. The two corrugated plates 22a and 22b are provided so that the concave portions and the convex portions face each other, and both side portions 23a and 23b are closed. The upper part forms a cooling water outlet header 24, and the lower part forms a similar cooling water inlet header 25. The cooling water enters the cooling water inlet header 25 from the cooling water supply pipe 26, rises between the two corrugated plates 22 a and 22 b, is guided from the cooling water outlet header 24 to the cooling water discharge pipe 27, and is further condensed. 4 is cooled.
[0012]
On the other hand, the absorption liquid is supplied to the bowl-shaped absorption liquid dispersion tray 28 provided at the upper part of the cooling water outlet header 24, and has a uniform thickness from the slit 29 provided in the tray 28 along the outside of the corrugated plate. It flows down into a film.
[0013]
As shown in FIG. 3, a plurality of absorbers 21 are provided in parallel to the direction in which the refrigerant vapor flows indicated by arrows 31. The size of the absorber 21 is, for example, a width A = 365 mm and a vertical B = 600 mm, and a single sheet is used as an absorber of 1 RT (freezing ton). Therefore, for a 100-RT absorption refrigerator, the five-lined arrangement shown in FIG.
[0014]
FIG. 5 is a cross-sectional view showing the shape of a corrugated plate used in the absorber 21 of the present invention. The cooling water rises on the inner surfaces of the two corrugated plates 22a and 22b, and the absorbent flows down the outer surfaces of the corrugated plates 22a and 22b along the corrugated plates 22a and 22b. In FIG. 5, the absorbing liquid film on the corrugated plate 22b is omitted. A concentrated aqueous solution of LiBr (LiBr approximately 63%) is used as the absorption liquid of a general absorption refrigerator. The surface tension of this liquid is as high as 86 dyn / cm and prevents the refrigerant absorbed in the absorbing liquid from being mixed quickly and uniformly. For this reason, a surface active agent such as n-octyl alcohol is added to reduce the surface tension to 20 to 30 dyn / cm. Experiments were conducted on corrugated plates of various shapes in order to form a film of absorbing liquid having approximately the same thickness in the upward portion 32a and the downward portion 32b of the corrugated plates 22a and 22b. Corrugated pitch P = 2-5 mm, preferably 3-4 mm, wave depth h = 0.5-2 mm, preferably 0.7-1.5 mm, peak bending radius r = 0.2-2 mm Preferably, 1.0 mm was obtained.
[0015]
FIG. 6 is a front view showing the groove shape of the absorbent dispersion tray used in the absorber 21 of the present invention. As a result of conducting a flow-down experiment using the absorbent, the absorbent having a slit width W = 0.5 to 1.5 mm, preferably 1 mm, and a slit interval S = 5 to 20 mm, preferably 10 to 15 mm is absorbed by the absorbent. It was found that a film having a uniform thickness was formed in the width direction of the vessel 21.
[0016]
As shown in FIG. 5, a core material 35 is provided in the vertical direction in the cooling water passage, and a baffle plate 36 is provided in a portion where the recesses face each other. The baffle plate 36 restricts the flow of cooling water in the vertical direction. 7 is a cross-sectional view taken along section line VII-VII in FIG. The core member 35 is a portion where the convex portions of the corrugated plates 22a and 22b are opposed to each other, is bent into a corrugated cardboard shape, maintains the shape of the corrugated plates 22a and 22b, and restricts the flow of the cooling water in the width direction. The flow of the cooling water is restricted by the core material 35 and the baffle plate 36 and becomes a turbulent flow, increasing the heat transfer efficiency.
[0017]
Further, the absorber of the present invention can be designed to be one sheet per 1RT or one sheet per 2RT, so that the cost can be reduced by mass production.
[0018]
【The invention's effect】
As described above, according to the present invention, the size of the absorber of the absorption chiller can be halved, and the size of the absorption chiller can be greatly reduced.
[Brief description of the drawings]
FIG. 1 is a system diagram for explaining the principle of an absorption refrigerator 1;
FIG. 2 is a front view of a plate-type absorber 21 for an absorption refrigerator according to an embodiment of the present invention.
FIG. 3 is a plan view of the absorber 21. FIG.
4 is a partial cross-sectional view of the upper portion of the absorber 21. FIG.
5 is an enlarged cross-sectional view showing the relationship between the corrugated plates 22a and 22b, the core material 35, and the baffle plate 36 of the absorber 21. FIG.
6 is an enlarged front view of the absorbent dispersion tray 28. FIG.
7 is a cross-sectional view taken along section line VII-VII in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Absorption type refrigerator 2 Regenerator 4 Condenser 7 Evaporator 8 Absorber 21 Plate type absorber 22 of one Example of this invention 22 Corrugated plate 23 Side part 26 Cooling water supply pipe 27 Cooling water discharge pipe 28 Absorbing liquid dispersion tray 29 Slit 35 Heart material 36 Baffle plate

Claims (4)

A regenerator that separates the refrigerant vapor from the diluted absorption liquid to obtain a concentrated absorption liquid, a condenser that cools the refrigerant vapor to obtain a refrigerant liquid, and an evaporation that evaporates the refrigerant liquid under reduced pressure and cools the liquid to be cooled. And an absorption refrigerator that absorbs refrigerant vapor generated in the evaporator with a concentrated absorption liquid and circulates the absorption liquid between the regenerator and the absorber through a heat exchanger.
Consists of two vertical corrugated plates with wavy irregularities horizontally and closed on both sides,
An absorption liquid dispersion tray is provided at the top, and the absorption liquid flows down from the absorption liquid dispersion tray along the outer surface of the two corrugated plates,
Cooling water is supplied from the lower part on one side, and discharged from the upper part on the other side, between the two corrugated plates .
A plate type absorber for an absorption refrigerator, wherein the two corrugated plates are combined so that the concave portions and the convex portions face each other, and a core material is disposed in the cooling water passage . 2. The plate-type absorber for an absorption refrigerator according to claim 1, wherein the absorbent dispersion tray is bowl-shaped, and a plurality of slits are provided in the upper and lower directions at equal intervals on both side surfaces. . 3. The absorption refrigerator according to claim 1, wherein the corrugated plate has a pitch of 2 to 5 mm, a wave depth of 0.5 to 2 mm, and a bending radius of a convex portion of 0.2 to 2 mm. Plate type absorber. The plate type absorber for an absorption chiller according to claim 2, wherein the absorbent dispersion tray is provided with slits of 0.5 to 1.5 mm at intervals of 5 to 20 mm.

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