JP2001317834A - Two stage double effect absorption refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely exhaust non-condensed gas in a high temperature absorber to the outside of a two stage double effect absorption refrigerating machine. SOLUTION: The two stage double effect absorption refrigerating machine includes a high temperature absorber 6, a low temperature absorber 7, a high temperature evaporator 4, and a low temperature evaporator 5. A gas phase part in the high temperature absorber and a gas phase part in the low temperature absorber are connected with each other through piping 22b. Hereby, non- condensed gas in the high temperature absorber is guided to the low pressure low temperature absorber from the high pressure high temperature absorber owing to a pressure difference therebetween. The non-condensed gas collected in the low pressure low temperature absorber is transferred out of the low temperature absorber together with an intermediate solution sprinkled in the low temperature absorber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an absorption refrigerator.
In particular, a two-stage 2 having two absorbers and two evaporators respectively
It relates to a heavy-effect absorption refrigerator.

[0002]

2. Description of the Related Art Examples of a two-stage evaporative absorption type absorption refrigerator having an absorber and an evaporator in two stages, which have the advantage of extracting cold heat below the ice temperature, are disclosed in JP-A-59-18355 and JP-A-59-18355. No. 11-304277. In these publications, water is used as a refrigerant and an aqueous solution of lithium bromide is used as an absorbing solution. However, since water is used as the refrigerant, the refrigerant may freeze. Therefore, the refrigerant is slightly mixed with the refrigerant in the low-temperature evaporator so that the refrigerant does not freeze even when the refrigerant temperature becomes 0 ° C. or less.

[0003]

Problems to be Solved by the Invention
No. 355 discloses a single-effect absorption refrigerator having only one generator, and JP-A-11-304277 discloses a two-stage double-effect absorption refrigerator having two regenerators. Each is listed. These absorption refrigerators are
Although it has the advantage of obtaining a fluid at a temperature of less than or equal to ° C., no consideration is given to the generation of non-condensable gas, which is an important issue in the absorption refrigerator, and the method of extracting the gas.

On the other hand, Japanese Patent Application Laid-Open No. H10-306959 discloses a method of extracting non-condensable gas in a normal absorption refrigerator which is not a two-stage evaporative absorption type. In the absorption refrigerator described in this publication, a region having a lower temperature than other regions is formed in the absorber, and the non-condensable gas is collected in the low temperature region to intensively bleed. In this absorption refrigerator, it is necessary to previously provide a region having a lower temperature than other regions in the absorber, and the device becomes complicated. Further, in order to make the bleeding position coincide with the region where the temperature is low, the temperature of the fluid flowing in the heat transfer tube around the bleeding position must always be controlled to be lower than the temperature of the cooling water flowing in the other heat transfer tubes. Control becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned disadvantages of the related art, and an object of the present invention is to make it possible to extract non-condensable gas with a simple structure in a two-stage double-effect absorption refrigerator.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is characterized in that a high-temperature regenerator, a low-temperature regenerator, a condenser,
A low-temperature absorber having a first liquid reservoir formed in a lower portion, a low-temperature absorber having a second liquid reservoir formed in a lower portion, a high-temperature evaporator and a low-temperature evaporator; In a two-stage double effect absorption refrigerator in which a cooling medium is absorbed and a circulation path of a cooling medium that radiates heat in a high-temperature evaporator is provided, a portion above the first liquid reservoir in the high-temperature absorber and a second liquid in the low-temperature absorber. A communication means is provided for communicating with the upper part of the reservoir, and the non-condensable gas of the high-temperature absorber is guided to the low-temperature absorber.

In this feature, a depression for the intermediate solution sprayed into the low-temperature absorber is provided above the second liquid reservoir, and an end of the communication pipe is arranged near the depression for the intermediate solution. Using a steam as a heating source of the high-temperature regenerator, and providing a drain cooler for exchanging heat between condensed water generated by heating the solution in the high-temperature regenerator and a dilute solution flowing out of the low-temperature absorber; A plurality of openings may be formed at the bottom of the heater, and another communication means for communicating the plurality of openings with the high-temperature evaporator may be provided to supply the refrigerant from the high-temperature regenerator to the low-temperature regenerator. It is desirable to use water as the refrigerant and an aqueous solution of lithium bromide as the absorbing solution.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a two-stage 2 according to the present invention.
1 shows a system diagram of an embodiment of a heavy-effect absorption refrigerator. In the high-temperature regenerator 1, the steam flowing through the steam pipe 18 and supplied from an external heat source heats the concentrated solution to generate refrigerant vapor. The refrigerant vapor generated in the high-temperature regenerator 1
And heats the dilute solution sent from the high-temperature absorber 6 and the low-temperature absorber 7 described later. The dilute solution is heated, and a part of the refrigerant vapor led from the high-temperature regenerator is condensed, and the latent heat of condensation at that time is used for heating. Refrigerant vapor is generated from the heated dilute solution.

[0009] The refrigerant vapor generated in the low-temperature regenerator 2 is sent to a condenser 3 maintained at a low pressure. Inside the condenser 3,
A condenser heat transfer tube 17a in which cooling water flows is disposed. The coolant flowing through the heat transfer tube 17a and the refrigerant vapor guided from the low-temperature regenerator exchange heat on the surface of the heat transfer tube 17a, and the refrigerant vapor is condensed to become a liquid refrigerant.

The liquid refrigerant obtained in the condenser 3 is stored in a liquid reservoir at the lower part of the condenser 3 and then sent from the bottom of the liquid reservoir to a refrigerant tank 13 formed at a lower part of the high-temperature evaporator 4. . Here, a refrigerant pipe 15 a is provided to communicate the refrigerant tank 13 with a mixed refrigerant tank 14 formed below the low-temperature evaporator 5.

The liquid refrigerant stored in the refrigerant tank 13 of the high-temperature evaporator 4 is guided by a refrigerant pump 11 to a spraying means disposed at an upper portion in the high-temperature evaporator 4. Then, it is sprayed from the spraying means around the heat transfer tube 17b arranged in the high-temperature evaporator 4. The sprayed liquid refrigerant exchanges heat with cold water flowing in the heat transfer tube 17b, and becomes refrigerant vapor. The liquid refrigerant that has not completely evaporated is stored in the refrigerant tank 13 and guided again to the spraying means by the refrigerant pump 11. Thereafter, this is repeated.

The low-temperature absorber 7 is provided with a heat transfer tube 17c, and the high-temperature evaporator 4 is also provided with a heat transfer tube 17b. These heat transfer tubes 17b and 17c are connected, and circulating water flows inside thereof. The circulating water is cooled by the latent heat of evaporation of the refrigerant flowing outside the heat transfer tube 17b in the high-temperature evaporator 4. Then, in the low-temperature absorber 7, the intermediate solution sprayed outside the heat transfer tube 17c is cooled.

Below the low-temperature evaporator 5, a mixed refrigerant tank 14 is provided. In this mixed refrigerant tank 14,
The unevaporated mixed refrigerant that has been scattered in the low-temperature evaporator 5 is stored. The refrigerant accumulated in the mixed refrigerant tank 14 is guided by the mixed refrigerant pump 12 to the spraying means arranged at the upper part in the low-temperature evaporator 5. Then, the heat is sprayed from the spraying means around the heat transfer pipe 17d arranged in the low-temperature evaporator 5. Brine flows through the heat transfer tube 17d, and water in the mixed refrigerant evaporates by heat exchange with the brine. On the other hand, the brine is cooled to below the ice temperature.

Since the moisture has evaporated from the mixed refrigerant, the concentration of the mixed refrigerant and the amount of the mixed refrigerant are controlled by supplying the water. Therefore, the mixed refrigerant tank 14 and the refrigerant tank 13 of the high-temperature evaporator 13 communicate with each other through the pipe 15a. Water as a refrigerant is supplied from the refrigerant tank 13 to the mixed refrigerant tank 14 through the communication pipe 15a. At this time, a control device (not shown) controls the control valve 16a interposed in the pipe 15a to set a predetermined mixed refrigerant concentration and mixed refrigerant amount. In order to detect the mixed refrigerant concentration, the concentration detecting means 20 is arranged in a pipe connecting the mixed refrigerant tank 14 and the spraying means 5b.
Although not shown, a liquid level gauge is attached to the mixed refrigerant tank 14 or its vicinity in order to detect the mixed refrigerant amount.

When replenishing water to the mixed refrigerant tank 14, a plurality of pipes 14a,
14a are used. The reason is as follows. A high-concentration mixed refrigerant is sprayed in the low-temperature evaporator 5.
Therefore, the refrigerant is dispersed from a plurality of pipes and the low-temperature evaporator 5 is dispersed.
When it flows into the inside, convection occurs due to the density difference between the mixed refrigerant stored in the mixed refrigerant tank 14 and the newly introduced water. This convection promotes the mixing of the refrigerant and the mixed refrigerant, and can prevent the inflowing water from freezing.

The concentrated solution generated by separating the refrigerant vapor in the high-temperature regenerator 1 and the low-temperature regenerator 2 is supplied to the solution heat exchangers 8a and 8
At b, heat exchange occurs with the dilute solution generated by being guided from the high-temperature absorber 6 to the low-temperature absorber 7 to lower the temperature. The low-temperature concentrated solution is sent to the high-temperature absorber 6 via the concentrated solution pipe 15b by the solution spray pump 9 arranged between the solution heat exchanger 8a and the solution heat exchanger 8b. A solution spraying means is arranged in the upper part of the high-temperature absorber 6, and the concentrated solution is sprayed around the heat transfer pipe 17e arranged in the high-temperature absorber 6 by the solution spraying means.

The sprayed concentrated solution is cooled by exchanging heat with cooling water flowing inside the heat transfer tube 17e. At the same time, it absorbs the refrigerant vapor evaporated in the high-temperature evaporator 4 and becomes an intermediate solution. The high-temperature absorber 6 and the low-temperature absorber 7 are connected by an intermediate solution pipe 15c. The solution circulation pump 10a interposed in the pipe 15c guides the intermediate solution from a solution tank provided below the high temperature absorber 6 to the solution heat exchanger 8c. In the solution heat exchanger 8c, the intermediate solution is supplied to the low-temperature absorber 7
Exchanges heat with the dilute solution sent from the plant, further lowering the temperature. The intermediate solution exiting the solution heat exchanger 8c is supplied to the low-temperature absorber 7
It is guided to the spraying means arranged at the upper part of the inside, and is sprayed from the spraying means around the heat transfer tube 17c arranged in the low-temperature absorber 7.

The sprayed intermediate solution heats the circulating water circulating in the heat transfer tube 17c and absorbs the refrigerant vapor generated in the low-temperature evaporator 5 to become a dilute solution.
Is stored in a solution tank provided at the lower part of the container. The dilute solution in the solution tank is supplied to a high-temperature regenerator 1 and a low-temperature regenerator 2 by a solution circulation pump 1 interposed in a dilute solution pipe for guiding the dilute solution.
By 0b, the solution is sequentially sent to the solution heat exchangers 8b and 8a. And finally, it is led to the high temperature regenerator 1 and the low temperature regenerator 2.

When the two-stage double effect absorption refrigerator is operating, only the water refrigerant evaporates out of the mixed refrigerant used in the low-temperature evaporator 5. Then, the evaporated refrigerant is absorbed in the intermediate solution in the low-temperature absorber 7. On the other hand, since the solute lithium bromide does not evaporate, the mixed refrigerant is gradually concentrated. Therefore, the refrigerant is supplied from the refrigerant tank 13 of the high-temperature evaporator 4 by the amount of the evaporated water refrigerant.

The concentration detecting means 20 interposed in the pipe 15e
The detected mixed refrigerant concentration is higher than a predetermined concentration,
When exceeding the preset upper limit, the control valve 16a interposed in the water refrigerant supply pipe 15a is opened for a predetermined time. As a result, a predetermined amount of the water refrigerant can be supplied from the high-temperature evaporator 4, and the mixed refrigerant concentration and the mixed refrigerant amount of the absorption refrigerator can be prevented from changing from the allowable values.

In this embodiment, the condensed water generated by condensing the vapor heated by heating the dilute solution in the high-temperature regenerator 1 exchanges heat with the dilute solution in the drain cooler 19 installed in the dilute solution pipe 15d. The water is returned to the external heating means such as the boiler.

Incidentally, in the absorption refrigerator, non-condensable gas may be generated due to aging or the like. This non-condensable gas causes a decrease in refrigeration capacity and an abnormal concentration of the absorbing solution. Therefore, a bleeding device for bleeding non-condensable gas to the outside of the absorption refrigerator has been provided. Therefore, in this embodiment, the non-condensable gas is led from the high-pressure high-temperature absorber 6 to the low-pressure low-temperature absorber 7 by utilizing the pressure difference between the high-temperature absorber 6 and the low-temperature absorber 7. By extracting the non-condensable gas only from the low-temperature absorber 7, the extraction device is simplified.

Specifically, a gas phase portion formed above the bottom surface of the solution tank of the high temperature absorber 6 and a gas phase portion formed above the bottom surface of the solution tank of the low temperature absorber 7 ,
Connected by piping 22b. And both ends 2 of the pipe 22b
A gas inflow / outflow portion is formed in 2a, 22c. According to this embodiment, both the high-temperature absorber 6 and the low-temperature absorber 7 have only the holes 22.
It is only necessary to open the holes a and 22c and connect the holes with pipes, so that the configuration is very simple and the work of mounting the pipes is also easy.

Next, a modification of the present invention is shown in FIG. This modification is different from the embodiment shown in FIG. 1 in that an end of the extraction pipe 22b for extracting non-condensable gas on the low-temperature absorber 7 side is provided with a depression portion for receiving an intermediate solution sprayed on the low-temperature absorber 7. 23. The non-condensable gas introduced from the high-temperature absorber is entrained in the intermediate solution to be sprayed and guided to the depression 23, so that the non-condensable gas can be reliably removed from the absorption refrigerator regardless of the size of the absorption refrigerator. Can be released to

FIG. 3 shows another modification of the present invention. This modification is different from the above embodiment in that the position of the drain cooler 19 is changed. That is, in the present modification, the drain cooler 19 is interposed in a pipe 15 f that branches off from the pipe 15 d that sends the dilute solution from the low-temperature absorber 7 to the low-temperature regenerator 2 and the high-temperature regenerator 1 and sends the dilute solution to the high-temperature regenerator 1. ing.

According to this modification, since the dilute solution sent to the high-temperature regenerator 1 and the steam flowing out of the high-temperature regenerator 1 exchange heat, an abnormal rise in the temperature of the solution flowing into the solution spray pump 9 can be prevented. Thereby, breakage of the solution spray pump 9 can be prevented. The same effect can be obtained by providing the drain cooler 19 in the pipe 15g, which branches from the pipe 15d and guides the dilute solution to the low-temperature regenerator 2, instead of the present modification.

[0027]

As described above, according to the present invention,
Since the non-condensable gas in the high-temperature absorber is moved to the low-temperature absorber by a pressure difference, the non-condensable gas can be reliably discharged from the absorption refrigerator with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a cycle system diagram of one embodiment of a two-stage double effect absorption chiller / heater according to the present invention.

FIG. 2 is a cycle system diagram of a modified example of the two-stage double absorption chiller / heater according to the present invention.

FIG. 3 is a cycle system diagram of another modification of the two-stage double effect absorption chiller / heater according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... High temperature regenerator, 2 ... Low temperature regenerator, 3 ... Condenser, 4 ... High temperature evaporator, 5 ... Low temperature evaporator, 6 ... High temperature absorber, 7 ... Low temperature absorber, 8a-8c ... Solution heat exchanger, 9: Solution spray pump, 10a, 10b: Solution circulation pump, 11: Refrigerant pump, 12: Mixed refrigerant pump, 13: Refrigerant tank, 14
... mixed refrigerant tank, 14a ... pipe, 15a-15g ... pipe, 16a-16c ... valve, 17a-17e ... heat transfer pipe, 1
8 steam pipe, 19 drain cooler, 20 concentration detection means, 21 auxiliary solution tank, 22a inlet, 22b
Piping, 22c ... Outlet, 23 ... Falling part.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akira Nishiguchi 502 Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in Machine Research Laboratory, Hitachi, Ltd. (Reference) 3L093 AA01 BB12 BB13 BB23 BB31 BB36 LL03

Claims (5)

[Claims] A high-temperature regenerator, a low-temperature regenerator, a condenser, a high-temperature absorber having a first liquid reservoir formed in a lower portion, a low-temperature absorber having a second liquid reservoir formed in a lower portion, a high-temperature evaporator, and A two-stage double effect absorption refrigerator having a low-temperature evaporator, wherein a cooling medium absorbs the heat of absorption generated by the low-temperature absorber and forms a circulation path of a cooling medium radiated by the high-temperature evaporator. A communication means is provided for communicating the upper part of the first reservoir of the absorber with the upper part of the second reservoir of the low-temperature absorber, and the non-condensable gas of the high-temperature absorber is guided to the low-temperature absorber. 2 stage double effect absorption refrigerator. 2. A lower portion of the intermediate solution sprayed in the low-temperature absorber is provided above the second liquid reservoir, and an end of the communication pipe is arranged near the lower portion of the intermediate solution. The two-stage double effect absorption refrigerator according to claim 1, characterized in that: 3. A drain cooler which uses steam as a heating source of the high-temperature regenerator and heat-exchanges condensed water generated by heating the solution with the high-temperature regenerator and a dilute solution flowing out of the low-temperature absorber. 2. The device according to claim 1, wherein
Stage double effect absorption refrigerator. 4. A low-temperature evaporator having a plurality of openings formed at a bottom thereof and another communication means for communicating the plurality of openings with the high-temperature evaporator. The two-stage double effect absorption refrigerator according to claim 1, wherein the water is supplied. 5. The two-stage double effect absorption refrigerator according to claim 1, wherein the refrigerant is water and the absorption solution is an aqueous solution of lithium bromide.