JP3852897B2 - Absorption refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an absorption refrigerator, and more particularly, to an absorption refrigerator using a liquid film plate heat exchanger as at least an absorber.
[0002]
[Prior art]
If the capacity and installation area of the absorption chiller are to be reduced, the shell-and-tube heat exchanger has a larger capacity than the heat transfer area. For example, adoption of a plate heat exchanger is considered. .
In particular, the present applicant has previously proposed a plate heat exchanger having a shape in which the heat transfer surfaces of the plate absorber and the plate evaporator face each other. For example, FIG. 9 shows a configuration diagram thereof. Such a plate heat exchanger can minimize the moving distance of the refrigerant vapor and can significantly reduce the vapor flow velocity. Therefore, if it is adopted, it is possible to greatly reduce the size of the absorption refrigeration machine (hereinafter referred to as “this”). The shape heat exchanger is called a new type heat exchanger).
One technical problem with these plate heat exchangers is the problem of extracting non-condensable gases.
[0003]
Generally, the capacity of an absorption refrigerator is greatly reduced when a gas other than refrigerant vapor (air leaking from the outside, hydrogen generated by corrosion of internal iron, etc.) exists even in a small amount. For this reason, the absorption refrigerator is usually provided with an extraction device (purge unit) and collects (extracts) non-condensable gas during operation.
In a conventional absorption refrigerator, an evaporator and an absorber are separate, and refrigerant vapor generated in the evaporator passes through a vapor passage connecting the absorber and the evaporator and is absorbed into the absorber. The amount of steam generated is about 0.06 m ³ per second per 1 kW of refrigerating capacity, and in the case of a conventional absorption refrigerator, the flow rate of steam in the steam passage reaches about 20 to 50 m per second.
[0004]
If this flow rate is high, the pressure loss increases, so that the absorption pressure of the refrigerant decreases, or liquid refrigerant is mixed into the refrigerant vapor, thereby deteriorating the efficiency of the refrigerator. Conversely, if the flow rate can be reduced, the performance of the refrigerator can be improved accordingly. In the absorption chiller of the type where the absorption surface and the evaporation surface face each other, the evaporated refrigerant is immediately absorbed, so the vapor flow rate can be suppressed to 1 m or less (about 0.8 m to 0.9 m) per second. The vessel pressure can be increased, the cooling water temperature can be increased, and the efficiency can be improved.
In the conventional absorption refrigerator, as described above, there is a vapor flow of 20 to 50 m per second, and since the flow is in a fixed direction from the evaporator to the absorber, the noncondensable gas is It is carried downstream by the flow of this refrigerant vapor. In particular, in the conventional absorption refrigerator, the vapor flow and the absorption solution flow direction are made the same, and consideration is given to the fact that even a little noncondensable gas flows downstream of the vapor flow.
[0005]
Further, it is usual that the cooling water is further flowed from the downstream side of the steam flow toward the upstream side so that the concentration of the noncondensable gas is increased on the downstream side of the steam flow as much as possible.
Accordingly, the noncondensable gas is likely to gather on the downstream side of the vapor flow of the absorber, and by extracting from here, the noncondensable gas can be discharged to the outside of the apparatus relatively effectively.
However, in the new heat exchanger, since the steam flow rate is slow and the moving distance is short, the non-condensable gas hardly collects in a specific place and is widely dispersed in the chamber, so that extraction is difficult. When such a plate-type absorber is employed, a technique for effectively extracting noncondensable gas has not yet been disclosed as a publicly available technique.
[0006]
If the non-condensable gas widely dispersed in the vessel is to be collected by “power”, the thin tube is extended to every corner of the absorber / evaporator, and a large-capacity purge unit is provided for extraction. This not only increases the price of the absorption chiller, but generally uses the discharge pressure of the absorption solution pump to drive the purge unit. Because it requires a large amount of power, it is not a realistic method.
As a practical means that can be considered, a low pressure chamber capable of keeping the refrigerant vapor partial pressure low is provided in the absorber (absorption / evaporator), and non-condensable gas is collected and extracted from there. There is a technique.
In order to make this low pressure chamber, the absorption solution that is originally cooled with cooling water is cooled with cold water, the refrigerant vapor partial pressure is kept low, thereby increasing the non-condensable gas partial pressure and facilitating extraction. Such a method can be considered. However, this is not a preferable method because a separate heat exchanger is provided in the absorber.
[0007]
[Problems to be solved by the invention]
In view of the above, the present invention is a small-sized non-condensable gas extraction means suitable for mass production that does not require a special heat exchanger or additional equipment while using a liquid film plate heat exchanger. It is an object to provide an inexpensive absorption refrigerator.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, an evaporator plate that functions as an evaporator and an absorber plate that functions as an absorber are mainly arranged alternately, and the heat transfer surfaces thereof face each other. and in absorption Osamushiki refrigerator with Ekimakushiki plate heat exchanger that performs two sets of heat exchange of the absorber, one end of the liquid film-type plate heat exchanger and the absorber plate, the end portion In addition, the absorption solution is supplied to the outermost surface of the absorber plate and the extraction passage for extracting the non-condensable gas is provided , and the refrigerant is not supplied to the outermost surface of the evaporator plate at the end portion which is not the absorber plate. it is obtained by the absorption chiller to be.
Further, in the present invention, an evaporator plate acting as steam Hatsuki, disposed absorber plate and alternating mainly acting as absorber has a structure facing the heat transfer surfaces from each other, the evaporator and absorber of 2 In an absorption chiller using a liquid film plate heat exchanger for performing heat exchange of a pair, two consecutive liquid crystal plate heat exchangers are arranged between alternately arranged evaporator plates and absorber plates. An absorber plate is arranged, an extraction passage for extracting non-condensable gas is provided between the two successive absorber plates, and an absorbing solution and a refrigerant are not supplied to both end faces of the liquid film plate heat exchanger. it is obtained by the absorption Osamushiki refrigerator you characterized.
[0009]
In the absorption refrigerator, between two successive absorber plate having a bleed path, Ru can insert scan Bae one server.
Furthermore, in the present invention, the evaporator plate that functions as an evaporator and the absorber plate that functions as an absorber are mainly arranged alternately, and the heat transfer surfaces thereof face each other. In an absorption chiller using a liquid film plate heat exchanger that performs heat exchange, cold water is internally contained between the evaporator plate and the absorber plate arranged alternately in the liquid film plate heat exchanger. is supplied, placed a plate absorption solution is supplied to the outside, the absorption Osamushiki refrigerator you characterized in that the incondensable gas is provided the bleed passage for bleeding between the plate facing the said plate be able to.
In the absorption refrigerator, the plate facing the plate may be an absorber plate.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Conventionally, the absorber surface and the evaporator surface correspond one-to-one, but the present invention dares to provide an absorber surface that does not face the evaporator surface, so that the flow of refrigerant vapor in the evaporator / absorber In this way, non-condensable gas is collected from various places in the vessel and the partial pressure of non-condensable gas is increased to facilitate extraction.
In the present invention, the absorption surface that does not face the evaporator is
1) Lowering the refrigerant vapor partial pressure to increase the partial pressure of the non-condensable gas 2) Simultaneously performing two actions of collecting the non-condensable gas together with the refrigerant vapor from various locations in the vessel. Regarding the effect of 1), the effect is well known for conventional shell and tube type absorption refrigerators. The effect of 2) is a problem and an effect characteristic of the absorption refrigerator having a structure in which the heat transfer surfaces of the evaporator and the absorber face each other.
In the present invention, a low-pressure surface that performs these two actions simultaneously can be realized by a simple method that is not particularly accompanied by production problems.
[0011]
In the present invention, the flow of the steam and the partial pressure of the steam are appropriately adjusted by changing the combination of the plates constituting the absorber / evaporator and the supply of the absorption solution and the refrigerant liquid, thereby forming a low-pressure portion. It collects condensable gas and tries to extract it.
Depending on the formation method of the low-pressure part, it can be divided into the following methods.
Utilizing end faces and intermediate faces that are difficult to use effectively (first method)
Making a surface with high absorption capacity by reassembling the plate (second method)
Using absorption plates cooled with cold water (third and fourth methods)
The method will be described below with reference to the drawings. In order to simplify the illustration, the cooling water and cooling water supply pipes are omitted, the cooling water is represented by a thick solid line, the cold water is represented by a thick dotted line, the absorbing solution is represented by a thin solid line, and the refrigerant is represented by a thin dotted line. ing.
[0012]
FIGS. 1 to 7 are explanatory views of a liquid film plate heat exchanger using each method. FIGS. 1 and 2 are a first method, FIGS. 3 and 4 are a second method, and FIGS. Are the third and fourth methods.
In the figure, 1 is an absorber plate through which cooling water 6 passes and the absorption solution 8 passes through, and 2 is an evaporator plate through which cold water 7 passes and refrigerant 9 passes through the outside. Is an absorbent solution supply path, 4 is a refrigerant supply path, 10 is an extraction pipe (extraction path), 11 is a non-condensable gas flow, and 12 is a low-pressure surface.
In the liquid film type plate heat exchanger as shown in the figure, the absorber plates 1 and the evaporator plates 2 are alternately arranged, and the heat transfer surfaces of the outer surfaces face each other, and evaporate on the outer surface of the evaporator plate 2. The cooled refrigerant 9 is absorbed by the absorbing solution 8 on the outer surface of the absorber plate 1 on the opposite side, and the cold water passing through the evaporator plate is cooled.
[0013]
Next, each drawing will be described.
Fig.1 (a) is explanatory drawing which bleeds a noncondensable gas using the 1st method.
In the new heat exchanger, the plates that serve as the evaporator and the plates that serve as the absorber are alternately arranged facing each other, so that the end faces (although they are the faces of the absorber and the evaporator, respectively) have no counterpart and are dead. It becomes. FIG. 1A shows that this aspect is actively used.
Considering the surface of the end in FIG. 9 as a dead surface, it is natural that neither the liquid nor the refrigerant is supplied. However, when the solution is supplied to the surface that becomes the absorber surface, this surface is the refrigerant vapor. Supply becomes insufficient, the concentration of the solution does not decrease compared to other parts, the refrigerant vapor partial pressure decreases, and it has the same function as the above-described low pressure chamber (this surface is called the low pressure surface 12).
[0014]
On the low pressure surface 12, not only the non-condensable gas partial pressure is increased, but also the insufficient refrigerant vapor is supplied from the other absorption surface, so that the non-condensable gas 11 gathers together with this refrigerant vapor flow. The vapor flow preferably follows the flow of the refrigerant and solution on the evaporator surface / absorber surface, and preferably the vapor flow as shown in the figure. Therefore, it is desirable to design the side surface with as little gap as possible between the new heat exchanger and the shell, and to provide an appropriate space at the bottom.
By providing the extraction pipe 10 on the low pressure surface thus created, effective extraction can be performed. In addition, the structural change of the absorption chiller by adopting this extraction system is only a slight increase in the number of supply channels and the size of the can body. It can be said that there is almost no.
[0015]
In the conventional example, there is a concept of supplying both the solution and the refrigerant without considering the end face as a dead face. In particular, as shown in FIG. 8, both the refrigerant and the solution are supplied on the surface of this end, and the heat transfer surface is considered. However, this is not considered a very good method considering the behavior of non-condensable gases. This is because the refrigerant evaporated on the evaporator surface at the end portion goes around to the other absorption surface and confines the noncondensable gas by this vapor flow. It is therefore important not only to supply the absorbing solution to the low pressure surface but also to make no other corresponding evaporator surface.
FIG. 1 (b) is a modification of FIG. 1 (a). When the number of absorber plates 1 is larger than that of the evaporator plate 2, both ends naturally become the absorber surfaces and both ends can be the absorption surfaces. The low pressure surface 12 can be made even more easily than the first method. Moreover, it is an effective method with no dead surface.
[0016]
FIG. 2 is an explanatory diagram of a heat exchanger to which the first method is applied.
The new heat exchanger is manufactured by a technique such as vacuum brazing, but the size of each element is limited due to restrictions such as the size of the furnace. Therefore, it is actually divided into units of an appropriate size and manufactured in combination. At this time, if the absorption surfaces 1 described above are arranged so as to face each other, only one extraction pipe 10 is required, which can be simplified.
FIG. 3 is an explanatory diagram for extracting non-condensable gas using the second method.
In the new heat exchanger, the absorber plates 1 and the evaporator plates 2 are arranged alternately. Here, if two absorber plates 1 can be arranged in succession by changing a part of the order, the function between the two absorber plates 1 is the same as that of the low pressure chamber. Therefore, by providing the extraction pipe 10 here, extraction can be performed effectively. Also by this method, the same effect as the first method can be obtained.
[0017]
In the new type heat exchanger, by arranging the plates having the same shape in different directions, they can be used as the absorber plate 1 or the evaporator plate 2 while having the same shape. At this time, in particular, in the heat exchanger in which the “communication pipe is configured as a part of each element plate”, the heat exchanger unit is not necessarily arranged alternately by alternately arranging the evaporator plate 2 and the absorber plate 1. Can be configured. In other words, it is possible to arrange two absorber surfaces by simply arranging the left and right alternately arranged plates in the same direction. Therefore, even with this method, there is almost no production burden or additional work. It's okay.
[0018]
4A and 4B, a modification of the second method shown in FIG. 3 will be described.
When the distance between the plates is narrow, it is not practical to provide a bleed pipe between the plates. Therefore, it may be necessary to provide a space for inserting the extraction pipe by inserting the spacer 13 into the low pressure portion 12. Further, the spacer and the bleed pipe can be integrated to form the bleed passage 14 (a method such as using a space inside the spacer as the bleed pipe).
FIG. 5 is an explanatory diagram for extracting non-condensable gas by using a modification of the third method.
In the first and second methods, the absorbing solution 8 is cooled by the cooling water 6, but by cooling the absorbing solution 8 with the cooling water 7, the refrigerant vapor partial pressure can be further lowered to facilitate extraction. This can be realized by changing the supply of refrigerant and solution to the plate.
That is, the structure of each plate is not changed, that is, the supply form of the cold water and the cooling water is not changed, and the solution 8 is supplied to the surface through which the cold water 7 flows as shown in the figure, and thus the same function as the low pressure chamber is achieved. You can make a part.
Even with this method, it can be said that there is almost no burden on production and no additional work.
[0019]
FIG. 6 is an explanatory diagram for extracting non-condensable gas using the fourth method.
The same effect as the third method can be obtained by changing the supply of the cold water and the cooling water of the plate without changing the supply of the absorbing solution and the refrigerant.
That is, since the supply of cold water and cooling water can be changed by changing the combination of the plates as in the second method, the same effect can be obtained.
FIG. 7 is an explanatory diagram for extracting noncondensable gas by a combination of the third method and the fourth method.
In the third method and the fourth method, two low pressure chambers can be formed, but if both are combined, one low pressure chamber can be formed.
1 to 7, the solution supply path 3 and the refrigerant supply path 4 are provided separately from the plates 1 and 2, but the supply paths may be integrated with each plate.
[0020]
【The invention's effect】
According to the present invention, a liquid film plate heat exchanger having a non-condensable gas extraction means suitable for mass production can be used by simply changing the flow path without using a special heat exchanger or additional equipment. A small and inexpensive absorption refrigerator was obtained.
[Brief description of the drawings]
FIG. 1A is an explanatory diagram for extracting a non-condensable gas using the first method, and FIG. 1B is an explanatory diagram of a modified method of FIG.
FIG. 2 is another explanatory diagram for extracting noncondensable gas using the first technique.
FIG. 3 is an explanatory diagram for extracting noncondensable gas using the second method.
FIGS. 4A and 4B are other explanatory views for extracting a noncondensable gas by using the second method. FIG.
FIG. 5 is an explanatory diagram for extracting non-condensable gas using a third method.
FIG. 6 is an explanatory diagram for extracting non-condensable gas using the fourth method.
FIG. 7 is an explanatory diagram for extracting noncondensable gas by a combination of the third and fourth methods.
FIG. 8 is an explanatory diagram of a conventional liquid film plate heat exchanger.
FIG. 9 is an explanatory diagram of a conventional liquid film plate heat exchanger.
[Explanation of symbols]
1: Absorber plate, 2: Evaporator plate, 3: Absorbing solution supply path, 4: Refrigerant supply path, 5: Liquid distributor, 6: Cooling water, 7: Cold water, 8: Absorbing solution, 9: Refrigerant, 10 : Extraction piping (extraction passage), 11: Flow of non-condensable gas, 12: Low pressure surface, 13: Spacer, 14: Extraction passage for spacer

Claims (5)

An evaporator plate that functions as an evaporator and an absorber plate that functions as an absorber are alternately arranged, and the heat transfer surfaces of the evaporator plate and the absorber are two sets of heat exchangers that face each other. in absorption Osamushiki refrigerator using a membrane-type plate heat exchanger, the liquid film type one end of the plate heat exchanger and the absorber plate, supplying the absorption solution in the uppermost end surface of the absorber plate of the end portion In addition, there is provided an extraction passage for extracting non-condensable gas, and the refrigerant is not supplied to the outermost end surface of the evaporator plate at the end which is not used as the absorber plate . An evaporator plate acting as steam Hatsuki, disposed absorber plate and alternating mainly acting as absorber has a structure facing the heat transfer surfaces from each other, perform two sets of heat exchange evaporator and absorber In an absorption refrigerator using a liquid membrane plate heat exchanger, two successive absorber plates are arranged between alternately arranged evaporator plates and absorber plates of the liquid membrane plate heat exchanger. , provided with a bleed passage for bleeding the incondensable gases between absorber plates the two successive, on both end faces of the liquid film type plate heat exchanger shall be the feature that it does not provide the absorbent solution and the refrigerant absorption Osamushiki refrigerator. The absorption refrigerator according to claim 2 , wherein a spacer is inserted between two continuous absorber plates provided with the extraction passage. An evaporator plate that functions as an evaporator and an absorber plate that functions as an absorber are alternately arranged, and the heat transfer surfaces of the evaporator plate and the absorber are two sets of heat exchangers that face each other. In an absorption refrigerator using a membrane plate heat exchanger, cold water is supplied between the evaporator plate and the absorber plate arranged alternately in the liquid membrane plate heat exchanger and absorbed outside. disposing a plate solution is supplied, suction Osamushiki refrigerator you characterized in that the incondensable gas is provided the bleed passage for bleeding between the plate facing the said plate. The absorption refrigerator according to claim 4, wherein the plate facing the plate is an absorber plate .

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