JP3013673B2 - Absorption refrigerator - 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 for water refrigerant, and more particularly to an absorption refrigerator suitable for use at a low temperature of about 0.degree.

[0002]

2. Description of the Related Art Conventionally, as a method of generating a low temperature of 0 ° C. or less, there is an absorption refrigerator using a refrigerant having a boiling point of 0 ° C. or less, such as Freon R22 or ammonia. However, Freon R
Reference numeral 22 denotes a refrigerant which is inconvenient for protection of the ozone layer, a refrigerant whose use is to be restricted in the future, and ammonia is a toxic refrigerant. Furthermore, the regenerator requires a container having a pressure higher than the atmospheric pressure and a durable container, and requires sufficient care in handling. Therefore, the regenerator is not widely used in Japan with a narrow population.

On the other hand, an absorption refrigerator using water as a refrigerant is extremely safe because the pressure of a regenerator is vacuum, and is widely used as a heat source device for building air conditioning. Basically, it consists of operatively connecting a regenerator, condenser, evaporator, absorber, liquid heat exchanger, solution circulation pump, etc., with a hygroscopic salt such as lithium bromide as the absorbent. ing. In the regenerator, the absorbent solution is heated and boiled by a heat source H such as a combustion gas of city gas, and the generated refrigerant vapor (water vapor) is cooled by cooling water in the condenser 2 to be condensed and liquefied into a liquid refrigerant. The liquid refrigerant thus generated in the condenser is guided to the evaporator 4 and is sprayed on the heat transfer tube to evaporate at about 4 to 6 ° C. And circulates where cooling is needed.

[0004] Japanese Patent Application Laid-Open No. 5-93555 is a related example of this type.

[0005]

In the above-mentioned conventional technology, water as a refrigerant freezes and cannot be used for refrigeration requiring a low temperature of about 0 ° C. That is, when water, which is a refrigerant, is sprayed on the tube group of the evaporator 4 under an evaporation pressure of 0 ° C. or less, the refrigerant itself freezes to take latent heat of evaporation from the refrigerant itself, so that the refrigerant is frozen on the heat transfer tube. The cycle could not be configured because it did not flow down.

An object of the present invention is to provide a low-pressure and safely operated absorption refrigerator which can be used for refrigeration requiring a low temperature of about 0 ° C.

[0007]

The above object is achieved by a first evaporation method.
Vessel, second evaporator, first absorber, second absorber, regenerator,
Contractor, liquid heat exchanger, solution circulation pump, refrigerant spray pump
Equipped with a pipe that operatively connects
In the absorption refrigerator, the liquid refrigerant of the first evaporator is used.
The second absorber may be arranged in a heat exchange relationship for cooling.
The refrigerant vapor evaporated in the second evaporator is used for the second absorption.
Refrigerant vapor introduced into the first evaporator and evaporated in the first evaporator is cooled.
And introduced into the first absorber cooled by the
The evaporator sucks into the liquid refrigerant flow path sent to the second evaporator.
Arranging a sorbent mixing means, the spray refrigerant of the second evaporator is
Exchanging heat with heat medium with mixed refrigerant and recovering heat from waste heat source
Has at least two regenerators, one of which is a condenser
And a regenerator for reheating the effluent solution of the regenerator
This is achieved by connecting to a shrink absorber group .

[0008] The above object is also achieved by a first evaporator and a second evaporator.
Vessel, first absorber, second absorber, regenerator, condenser, liquid heat exchange
Exchanger, solution circulation pump and refrigerant spray pump
Equipped with connected piping, absorption cooling using saline solution as absorbent
In the refrigerating machine, the second refrigerant is absorbed by the liquid refrigerant of the first evaporator.
The heat exchanger for cooling the vessel,
The refrigerant vapor evaporated in the evaporator is introduced into the second absorber.
And the refrigerant vapor evaporated in the first evaporator is cooled by cooling water.
Introduced into the first absorber, and the first evaporator
Mixes the absorbent into the liquid refrigerant passage sent to the second evaporator.
Means for dispersing the refrigerant in the second evaporator so that the mixed refrigerant
Group of regenerators that exchange heat with the heat medium and recover heat from the exhaust heat source
Have at least two, one of which is connected to the condenser.
The regenerator for reheating the effluent from the regenerator
Connected to the absorber group and sent to the evaporator
An absorbent mixing means is disposed in the liquid refrigerant flow path to disperse the evaporator.
The cloth refrigerant is achieved by exchanging heat with the heat medium with the mixed refrigerant.
Is done.

Further, the above object is achieved by a first evaporator and a second evaporator.
Vessel, first absorber, second absorber, regenerator, condenser, liquid heat exchange
Exchanger, solution circulation pump and refrigerant spray pump
Equipped with connected piping, absorption cooling using saline solution as absorbent
In the refrigerating machine, the second refrigerant is absorbed by the liquid refrigerant of the first evaporator.
The heat exchanger for cooling the vessel,
The refrigerant vapor evaporated in the evaporator is introduced into the second absorber.
And the refrigerant vapor evaporated in the first evaporator is cooled by cooling water.
Introduced into the first absorber, and the first evaporator
Mixes the absorbent into the liquid refrigerant passage sent to the second evaporator.
Means for dispersing the refrigerant in the second evaporator so that the mixed refrigerant
Evaporator tube in which heat exchange with the heat medium is carried out and the mixed refrigerant is sprayed
Achieved by staggering rows and rows of absorber tubes
Is done.

[0010]

[0011]

[0012]

When the liquid refrigerant generated in the condenser is mixed with an absorbent and introduced into the second evaporator, the mixed refrigerant has a higher boiling point.
On the other hand, since the freezing temperature is lowered, the material does not freeze even at 0 ° C. or less. Therefore, the mixed refrigerant sprayed on the heat transfer tube group in the second evaporator flows down the heat transfer tube group without freezing even if the evaporation temperature becomes 0 ° C. or less, and the cooling medium flowing through the heat transfer tube, For example, the antifreeze (brine) can be cooled to supply a low-temperature brine of about 0 ° C.

Here, since the absorbent mixing means is disposed in the refrigerant spray duct of the evaporator, the lowering of the freezing temperature and the higher boiling point of the mixed refrigerant are grasped by the means for detecting the boiling point and the freezing temperature of the mixed refrigerant. By opening the control valve, the absorbent concentration of the mixed refrigerant is reduced by opening the control valve to lower the in-machine pressure equilibrium temperature, the freezing temperature approaches 0 ° C., and the control valve is compared with the temperature detected by the temperature sensor. By controlling the concentration by opening it to increase the internal pressure equilibrium temperature and lower the freezing temperature to below 0 ° C to control the difference in heat exchange temperature due to the rise in the boiling point of the mixed refrigerant, Control can be performed to increase the amount of exchanged heat.

The first evaporator cools the second absorber in a heat exchange relationship, and the refrigerant vapor evaporated in the second evaporator is introduced into the second absorber and evaporates in the first evaporator. The refrigerant vapor is introduced into the first absorber cooled by the cooling water, and the second evaporator is provided with absorbent mixing means,
Since the sprayed refrigerant exchanged heat with the heat medium with the mixed refrigerant, the cooling water for cooling the first absorber can be cooled by the cooling water of about 32 ° C. obtained by a normal cooling tower or the like. A cycle configuration is possible without concentrating the agent concentration to a high concentration near the crystal line. That is, an example of the absorption refrigeration cycle of the present invention is shown in the During diagram of FIG. The symbols in the figure are operating points of the cycle and correspond to the constituent devices. As is clear from the figure, when the refrigerant in the first evaporator is a pure water refrigerant as in the present embodiment, the evaporation temperature can be set to about 20 ° C., and the heat exchange temperature difference with the absorption temperature of the second absorber about 35 ° C. Has an effect that can be greatly increased to about 15K. When the sprayed refrigerant of the first evaporator is a mixed refrigerant, the evaporation temperature of the first evaporator is about 25 ° C., which is a temperature difference of about 10 K from the absorption temperature of the second absorber of about 35 ° C.

[0015]

FIG. 1, FIG. 2 and FIG. 3 show an embodiment of the present invention.
It will be explained by.

The absorption refrigerator includes a regenerator 1, a condenser 2, a first evaporator 3A, a second evaporator 3B, a first absorber 4A, a second absorber 4B, a liquid heat exchanger 5, a solution circulation pump 6, and the like. Are operatively connected. In the regenerator 1, a heating means H for heating and boiling the absorbent solution with steam or combustion gas such as city gas is disposed. Refrigerant vapor (water vapor) generated in the regenerator 1 is introduced into the condenser 2 and cooled by the cooling water CW flowing in the condenser heat transfer tube, condensed and liquefied to become a liquid refrigerant.
The liquid refrigerant generated in the condenser 2 is passed through the liquid refrigerant conduit 14 to the cooling heat exchange means 20 of the second absorber 4B of the first evaporator 3A.
The refrigerant vapor is sprayed and evaporated, and the refrigerant vapor is guided to the first absorber 4A. Further, the second absorber 4B is cooled by the latent heat of evaporation via the cooling heat exchange means 20. The unevaporated refrigerant in the first evaporator 3A is held in the lower refrigerant tank 15A. The bottom of the refrigerant tank 15A and the suction pipe 16 of the refrigerant spray pump 7 are connected by a refrigerant conduit 17, and the liquid refrigerant is sent to the second evaporator 3B. A refrigerant spray duct 18 is connected to the discharge side of the refrigerant spray pump 7, and an absorbent mixing means 9 is disposed. The refrigerant becomes a mixed refrigerant on the heat transfer tube group of the second evaporator 3 </ b> B. The mixed refrigerant is sprayed. The unevaporated mixed refrigerant is stored in the mixed refrigerant tank 15B, sucked again by the refrigerant spray pump 7 and sprayed on the heat transfer tube group of the second evaporator 3B to evaporate the refrigerant. The brine flowing in the heat transfer tube group of the evaporator 3B is cooled. The brine is sent to the air brine heat exchanging means 22 of the refrigerated warehouse 21 by the pump 19 to cool the air in the refrigerated warehouse 21, and then the second evaporator 3 is cooled again.
B flows into the heat transfer tube group.

On the other hand, the absorbent that has been concentrated by generating refrigerant vapor in the regenerator 1 exchanges heat with the dilute solution in the solution heat exchanger 5 to become low in temperature. Absorber 4
B on the cooling heat exchanging means 20 and the first evaporator 3A
The refrigerant is cooled by the latent heat of evaporation of the refrigerant and absorbs the refrigerant vapor from the second evaporator 3B and becomes thin. This thinner absorbing solution is further subjected to a first spray by a solution spray pump 8.
The water is sent to the absorber 4A, is sprayed on the heat transfer tube group of the first absorber 4A, and is cooled by the cooling water flowing through the tubes.
The refrigerant vapor evaporated by the evaporator 3A is absorbed and further diluted to become a dilute solution. The dilute solution is supplied by the solution circulation pump 6 via the pump suction pipe 27, the dilute solution conduit 25 via the solution heat exchanger 5, and the regenerator. Sent to 1. These pieces of refrigeration load information are sent to the refrigerator control panel 30 and used for controlling the heating source. That is, when the refrigeration load is large and the brine temperature is high, the heat input is increased, and when the brine temperature is low and the refrigeration load is small, control is performed so as to limit the heat input.

The cycle is configured as described above.
Here, the absorbent mixing means 9 comprises a solution conduit 26 connecting the dilute solution conduit 25 and the refrigerant spray duct 18 and a flow control valve 10 disposed in the solution conduit 26; (1) a liquid refrigerant blow pipe 28 communicating with the absorber 4A, a blow amount control valve 11 disposed in the liquid refrigerant blow pipe 28, an absorbent concentration sensor 12 for liquid refrigerant disposed in the refrigerant spray duct 18; Brine outlet temperature sensor
29, an arithmetic and control unit 13.

Further, the cooling heat exchanging means 20 includes the second absorber 4
B and a means for exchanging heat between the first evaporator 3A and constituted by a horizontal heat pipe 23, and a heat exchanger on the second absorber 4B side.
The refrigerant is condensed in the top pipe 23, and the liquid refrigerant evaporates on the first evaporator 3A side to smoothly exchange heat.

Next, the operation will be described. When the absorbent is mixed with the liquid refrigerant generated in the condenser 2 and introduced into the second evaporator 3B, the mixed refrigerant has a higher boiling point, but also has a lower freezing temperature, so that it does not freeze even at 0 ° C. or lower. Become nature. Therefore, the mixed refrigerant sprayed on the heat transfer tube group in the second evaporator 3B flows down the heat transfer tube group without freezing even when the evaporation temperature becomes 0 ° C. or less, and flows through the heat transfer tube. For example, it is effective to cool antifreeze (brine) and supply low-temperature brine of about 0 ° C.

Here, since the absorbent mixing means 9 is arranged in the refrigerant spray duct 18 of the second evaporator 3B, as shown in FIG. The freezing temperature drop and the boiling point rise of the mixed refrigerant are grasped by the sensor 12 and the arithmetic control means 13, and compared with the temperature grasped by the cooled medium temperature sensor 29,
Although the concentration of the absorbent in the mixed refrigerant is reduced by opening the blow amount control valve 11 and the freezing temperature approaches 0 ° C., the pressure equilibrium temperature in the evaporator can be lowered, and the concentration can be reduced by opening the flow control valve 10. To control the freezing temperature of the mixed refrigerant to a low temperature side and control the pressure equilibrium temperature in the evaporator to reduce the heat exchange temperature difference due to the rise in the boiling point, so that the amount of heat exchanged is increased. Can be

In this embodiment, the valves 10 and 11 use electromagnetic valves. However, it is apparent that the absorbent concentration of the mixed refrigerant can be controlled by proportional control using a motor-operated valve or control using a small pump. is there.

Here, the first evaporator 3A and the second absorber 4B
Are arranged in a heat exchange relationship for cooling, and refrigerant vapor evaporated in the second evaporator 3B is introduced into the second absorber 4B,
In addition, the refrigerant vapor evaporated in the first evaporator 3A is configured to be introduced into the first absorber 4A cooled by the cooling water, and the absorbent mixing means 9 is disposed in the second evaporator 3B so that the scattered refrigerant can be dispersed. Since the heat exchange with the heat medium was performed by the mixed refrigerant, the first absorber 4A
The cooling water for cooling is about 32
It becomes possible to cool with cooling water of ° C., and a cycle configuration becomes possible without concentrating the absorbent concentration to a high concentration near the crystal line. That is, an example of the absorption refrigeration cycle of the present invention is shown in the During diagram of FIG. In the During diagram, the vertical axis represents the pressure equilibrium saturation temperature of the pure refrigerant, and the symbol on the horizontal axis represents the operating point of the cycle, corresponding to the component equipment. As is clear from the figure, when the refrigerant in the first evaporator 3A is pure water refrigerant as in the present embodiment, the evaporation temperature can be set to about 20 ° C., and heat exchange with the absorption temperature of the second absorber 4B to about 35 ° C. There is an effect that the temperature difference can be as large as about 15K. In the case where the sprayed refrigerant of the first evaporator 3A is a mixed refrigerant, the evaporation temperature of the first evaporator 3A is about 25 ° C., and the temperature difference of about 10K from the absorption temperature of the second absorber 4B of about 35 ° C. Therefore, the present embodiment in which the pure refrigerant is evaporated by the first evaporator 3A is extremely effective in reducing the size of the heat exchanger.

FIG. 4 is a cycle system diagram of another embodiment of the present invention. In FIG. 4, the same reference numerals as those in FIG. 1 have the same functions, and thus description thereof will be omitted. The difference between this embodiment and the embodiment shown in FIG. 1 is as follows.

The point that the process of generating the refrigerant and the process of concentrating the absorbent in the absorption refrigeration cycle is a so-called parallel flow double effect absorption cycle. The regenerator 1 is composed of a high-temperature regenerator 31 and a low-temperature regenerator 32 that uses the latent heat of condensation of the refrigerant vapor generated in the high-temperature regenerator 31 as a heat source. Then, refrigerant vapor is generated and concentrated. That is, the high-temperature regenerator 31 heats the absorbing solution by the external heat source H to generate refrigerant vapor, is guided into the heat transfer tube of the low-temperature regenerator 32, condenses and liquefies, and flows into the condenser 2. The low-temperature regenerator 32 heats the absorbing solution by the latent heat of condensation of the refrigerant vapor generated in the high-temperature regenerator 31 to generate refrigerant vapor, and the generated refrigerant vapor is guided to the condenser 2 and cooled by cooling water to condense and liquefy. Then, the refrigerant is sent to the first evaporator 3A together with the refrigerant condensed in the heat transfer tube of the low-temperature regenerator 32.
In addition, a high-temperature heat exchanger 33 for exchanging heat between the absorbing solutions entering and exiting the high-temperature regenerator 31 is provided, so that the amount of heating to the high-temperature regenerator 31 is reduced. By improving these refrigerant generation and absorbent concentration processes, a refrigerant generated in the high-temperature regenerator 31 and a refrigerant generated in the low-temperature regenerator 32 can be obtained, and this refrigerant can be subjected to a refrigeration operation in the evaporator. The heat energy required for operating the refrigerator can be saved, and the refrigerant can be efficiently generated.

The first evaporator 3A is provided with a liquid refrigerant spraying device 34 at the upper part and reticulated liquid refrigerant jump-up prevention plates 35 and 36, a refrigerant liquid level switch 38, and a refrigerant spray pump 7A at the lower part. Is connected to the first absorber 4A via the eliminator 37. The low-temperature liquid refrigerant in the liquid refrigerant tank 15A of the first evaporator 3A flows through the heat transfer pipe of the second absorber 4B by the refrigerant spray pump 7A, cools the absorbing liquid outside the pipe, and rises in temperature. From the refrigerant spray device 34 to the first evaporator 3
A part of the liquid refrigerant is sprayed into the space in A and becomes a low-temperature liquid refrigerant again by evaporating a part of the liquid refrigerant. The refrigerant liquid level switch 38 is a safety switch for preventing idling due to a shortage of liquid refrigerant of the refrigerant spray pump 7A. The refrigerant evaporated in the first evaporator 3A is absorbed by the absorption solution in the first absorber 4A via the eliminator 37.

As described above, the second absorber 4B is cooled. A circulating refrigerant temperature sensor 39 is disposed in the refrigerant suction section of the refrigerant spray pump 7A, and the number of revolutions of the refrigerant spray pump 7A is controlled by controlling the rotation speed of the refrigerant spray pump 7A based on the temperature signal. Since the cooling of the two absorbers 4B can be controlled, the cycle can be stably operated.

The second evaporator 3B is provided with a liquid spraying device at the upper part, a heat transfer tube group through which a medium to be cooled flows in the pipe, a mixed refrigerant tank 15B, a mixed refrigerant liquid level detecting means 38B, and a mixed refrigerant spray pump 7B below the liquid spraying device. Have been. The liquid refrigerant of the first evaporator 3A is connected to a suction pipe of the mixed refrigerant spray pump 7B via a refrigerant conduit 40 branched from a discharge pipe of the refrigerant spray pump 7A and a refrigerant flow control valve 41.
The refrigerant flow control valve 41 is opened and closed by the control signal of the mixed refrigerant liquid level detecting means 38B, and the liquid refrigerant of the first evaporator 3A is sent to the second evaporator 3B, mixed with the mixed liquid refrigerant and mixed with the mixed refrigerant spray. -The mixed refrigerant is sprayed from the liquid spraying device to the heat transfer tube group via the spray duct 18 by the pump 7B. An absorbent mixing means 9 is disposed in the spray duct 18 to control the absorbent concentration of the mixed refrigerant circulating in the second evaporator 3B.

With the above configuration, first, the first evaporator 3A does not require a heat transfer tube, and has an effect of reducing costs. Further, the low-temperature liquid refrigerant generated in the first evaporator 3A is caused to flow into the heat transfer tube of the second absorber 4B, and the absorption solution flowing down outside the tube can be efficiently cooled by forced convection cooling in the tube. The second absorber 4B saves the amount and
, And the temperature difference between the refrigerant temperature of the first evaporator 3A and the refrigerant temperature of the first evaporator 3A can be reduced, so that the cycle can be efficiently operated. In addition, since the first evaporator 3A evaporates the pure refrigerant and the second evaporator 3B evaporates the mixed refrigerant and does not mix the two, there is an effect that the operation can be performed with high efficiency.

FIG. 5 is a cycle system diagram of still another embodiment of the present invention. In FIG. 5, the same reference numerals as those in FIG. 4 have the same functions, and thus description thereof will be omitted. This embodiment and FIG.
The difference from the embodiment shown in FIG.

The second pump is provided by the refrigerant pump 7 of the first evaporator 3A.
The refrigerant flows through the heat transfer tube of the absorber 4B, circulates again to the first evaporator 3A, branches off a part of the liquid refrigerant, passes through the flow control mechanism 41B, and further has the refrigerant in which the absorbing liquid mixing means 9 is disposed. The spray is spread on the heat transfer tube group of the second evaporator 3B via the spray duct 18. The refrigerant exchanges heat with the medium to be cooled flowing down the heat transfer tube group of the second evaporator 3B and evaporates, and the remaining mixed refrigerant flows into the suction pipe of the refrigerant spray pump 7 of the first evaporator 3A. Return via conduit 40. By arranging the second evaporator 3B at a higher position than the first evaporator 3A so that the liquid refrigerant hardly stays in the refrigerant tank 15B, the liquid level of the refrigerant is reduced to the first evaporator 3A. Only the refrigerant tank 15A. As a result, if the concentration of the absorbent in the circulating solution of the absorption refrigeration cycle is excessively concentrated and crystallization is a concern, the refrigerant overflows from the first evaporator 3A to dilute the circulating solution. This has the effect of preventing crystallization of the compound and enabling safe operation. Since the refrigerant in the first evaporator 3A is a mixed refrigerant, the difference in heat exchange temperature is reduced by the rise in boiling point due to the mixing of the absorbent, but the mixed refrigerant spray pump in the second evaporator 3B is not required, and the system is not required. There is an effect that can be simplified. Further, the refrigerant overflow from the second evaporator 3B is detected by detecting the flow rate of the mixed refrigerant in an overflow pipe (not shown), and the flow control mechanism 41B is throttled to reduce the excess of the mixed refrigerant. Can be controlled to prevent the outflow of water, and there is an effect that energy can be saved. FIG. 6 is a cycle system diagram of still another embodiment of the present invention. In FIG. 6, the same reference numerals as those in FIG. 4 have the same functions, and thus description thereof will be omitted. The difference between this embodiment and the embodiment shown in FIG. 4 is as follows.

The refrigerant generation and absorbent concentrating process of the absorption refrigeration cycle is referred to as a so-called series flow double effect absorption cycle, and the dilute solution in the second absorber 4B passes through the liquid heat exchanger 5 and the high temperature heat exchanger 33. Into the high-temperature regenerator 31, heated by the external heat source H, concentrated and passed through the high-temperature heat exchanger 33, and the low-temperature regenerator 32 using the latent heat of condensation of the refrigerant vapor generated in the high-temperature regenerator 31 as a heat source Is sprayed on the tube group. The solution sprayed on the low temperature regenerator 32 is heated by the latent heat of condensation of the refrigerant vapor generated in the high temperature regenerator 31, generates refrigerant vapor, is concentrated, passes through the liquid heat exchanger 5, and is passed through the first absorber 4A.
Return to

As described above, this is a method in which the solution is flowed through the series in the order of the high temperature regenerator 31 and the low temperature regenerator 32. Conversely, there is a so-called reverse flow system in which the solution is circulated through the low-temperature regenerator 32 and the high-temperature regenerator 31, and these double-effect absorption refrigeration cycle flows are similar to the above-described parallel flow. This has the effect of saving energy of external heat input.

The second pump is provided by the refrigerant pump 7 of the first evaporator 3A.
The refrigerant flowing through the heat transfer tube of the absorber 4B and circulating again to the first evaporator 3A, branching off a part of the liquid refrigerant, and having the absorbing liquid mixing means 9 disposed via the refrigerant spray amount control valve 41. The spray is spread on the heat transfer tube group of the second evaporator 3B via the spray duct 18. The second refrigerant evaporates by exchanging heat with the medium to be cooled flowing down the heat transfer tube group of the second evaporator 3B and evaporating, and the remaining mixed refrigerant is sent to the second absorber 4B and mixed with the solution. Is sent to the regenerator group by the solution circulation pump 6.

Here, the refrigerant to be sprayed to the second evaporator 3B is sprayed after the concentration of the absorbent is controlled by the flow control valve 10 which is the absorbent mixing means 9 according to the signal of the cooling medium temperature sensor 29. You. The amount of the refrigerant sprayed to the second evaporator 3A depends on the refrigeration load.
Since it is controlled and sprayed by 1, the large amount of the unevaporated refrigerant does not flow out to the second absorber 4B to increase the heat loss. Furthermore, there is an effect that the control system of the absorbent mixing means 9 can be simplified.

In this embodiment, the liquid refrigerant supplied to the second evaporator 3B is supplied by branching the liquid refrigerant from the first evaporator 3A from the discharge side of the refrigerant spray pump 7. There is also a method of simplifying the flow through the refrigerant spray flow rate control valve 41 and the absorbent mixing means 9 by branching off. Further, the absorbent mixing means 9 can be a simple orifice by mixing a certain amount of the absorbent with the refrigerant so that the concentration of the absorbent in the mixed refrigerant is substantially constant.

FIG. 7 shows an example of the structure of an evaporator absorber according to still another embodiment of the present invention. In FIG. 7, the same reference numerals as those in FIG. 4 have the same functions, and thus description thereof will be omitted. The difference between this embodiment and the embodiment shown in FIG. 4 is as follows.

In FIG. 7, the second evaporator 3B is composed of two rows of heat transfer tube groups, and a second absorber 4A composed of two rows of heat transfer tube groups is opposed to each other. A droplet lowering device 51 is disposed above the heat transfer tube group in each row, and a tray 52 is disposed below the evaporator, so that unevaporated refrigerant can be collected and circulated and dropped again. At the center of each of the two rows of absorber tube groups, a bleed tube 53A having a hole formed in a flat tube is arranged, guided from a bleed tube header 53 to a bleed absorber 54, cooled by a refrigerant or low-temperature cooling water, The non-condensable gas is mixed and flows down the liquid mixing pipe 56, and is separated into liquid and non-condensable gas by the gas-liquid separator 57, and the liquid is returned to the solution of the absorber by the gas-liquid mixing pipe 58 having a rising portion. The separated non-condensable gas is stored in the storage tank 60 via the gas riser 59. Also, the bleed absorber 54 is connected to the refrigerant pump 7B of the second evaporator 3B.
The liquid refrigerant branch pipe 55 branched from the discharge side is connected and cooled.

With the above configuration, a large refrigerant vapor flow path from the evaporator 3 to the absorber 4 tube group can be secured, the vapor flow pressure loss can be reduced, and the performance can be prevented from deteriorating. In particular, in the case of the present absorber that operates in a low-temperature vacuum, the ratio of the vapor flow pressure loss to the refrigerant evaporation pressure increases,
When the tube group is enlarged, the movement of the refrigerant vapor is hindered, so that the pressure loss is further increased, and an absorption refrigeration cycle that generates a low temperature cannot be configured. By arranging the evaporator and the absorber close to each other as disclosed in FIG. 7, the steam flow pressure loss can be reduced, so that a low-temperature absorption refrigeration cycle can be realized.

The presence of the non-condensable gas in the absorber hinders the absorption of refrigerant vapor. For very low pressure absorbers, efficient bleeding is essential. As in the present embodiment, a non-condensable gas can be efficiently extracted by stretching an extraction tube in the tube group and guiding it to the extraction absorber, so that there is an effect that a low-temperature absorption refrigeration cycle can be realized.

In FIG. 7, the gas-liquid mixing pipe 58 is connected to the first
It is also effective to connect the solution to the suction of the solution pump of the absorber 4A, send it to the first absorber side where the pressure is relatively high and is not easily affected by the non-condensable gas, and perform the bleeding process in the first absorber. Thereby, there is an effect that the system can be simplified by omitting the gas-liquid separation device 57 and the gas storage tank 60.

FIG. 8 is a cycle system diagram of still another embodiment of the present invention, and FIG. 9 is a During diagram of the absorption refrigeration cycle of the embodiment of FIG. In FIGS. 8 and 9, the same reference numerals as those in FIGS. 4 and 2 have the same functions, and thus description thereof will be omitted.

Hereinafter, this embodiment will be described. The regenerator 1 is composed of a vertical tube group, a fin orthogonal to the tube group, and a cross fin tube heat exchanger composed of a lower header and an upper header. Then, the solution is exchanged with the absorbing solution in the tube, and the solution is concentrated by generating refrigerant vapor. The concentrated solution is sent to the regeneration chamber 61 by the solution transport means 63. The regeneration chamber 61 includes a cross tube heat exchanger including a vertical tube bank, fins orthogonal to the tube bank, a lower header and an upper header. The regeneration chamber 61 is arranged on the exhaust gas downstream side of the regenerator 1. The gas phase of the regeneration chamber 61 is connected to the absorption chamber 62. Here, the absorption chamber 62 includes a solution spraying device and a heat transfer tube group, and cooling water whose temperature has been increased by cooling the first absorber 4A and the condenser 2 flows through the heat transfer tube. On the other hand, the dilute solution from the second absorber 4B through the heat exchanger 5 is sprayed by the solution circulation pump 6 from the second absorber 4B and cooled, and the refrigerant vapor generated in the regeneration chamber 61 is absorbed and absorbed in the regeneration chamber 61. The solution is further concentrated. The solution diluted by absorbing the refrigerant vapor in the absorption chamber 62 is sent to the regenerator 1 by the liquid transport means 65. Further, the absorbing solution concentrated in the regeneration chamber 61 is
Flows into the first absorber 4A via the heat exchanger 5,
The solution spray pump 8 is sprayed to the first absorber 4A and the second absorber 4B to absorb the refrigerant vapor. On the other hand, the liquid refrigerant generated in the condenser 2 is guided to the first evaporator 3A, flows through the pipe of the second absorber 4B by the refrigerant circulation pump 7A, cools the second absorber 4B, and is self-evaporated. The refrigerant vapor is generated, and the generated refrigerant vapor is absorbed by the solution in the first absorber 4A. Further, the liquid refrigerant of the first evaporator 3A is guided to the mixed refrigerant flow path of the second evaporator 3B, and is dispersed by the mixed refrigerant spray pump 7B onto the second evaporator 3B heat transfer tube group, and the brine flows through the tubes. The refrigerant vapor that evaporates due to heat exchange is absorbed by the absorbing solution in the second absorber 4B. Note that the absorbent concentration of the mixed refrigerant in the second evaporator 3B is controlled by a signal from the absorbent concentration sensor 12, and the absorbent mixing means 9 is composed of a flow control valve 10 and a blow amount control valve 11. Is optimally controlled.

FIG. 9 shows the absorption refrigeration cycle described above in a During diagram of lithium bromide-water. The regenerator operates at about 82 ° C, the regeneration chamber 61 operates at about 62 ° C, the first absorber 4A operates at 42 ° C, and the second absorber 4B operates at 2 ° C.
Operating at 0 ° C., the absorption chamber 62 operates at 45 ° C. The condenser 2 operates at 42 ° C., and the first evaporator 3A
Operating at 0 ° C, the second evaporator is operating at -5 ° C. As the absorbent, in addition to lithium bromide, an absorbent other than lithium chloride can be used, and a refrigerant mainly composed of water mixed with 2-ethylhexanol, methanol, or the like can be used.

As described above, since the regeneration chamber 61 and the absorption chamber 62 heated by the exhaust gas are arranged, heat is recovered from the relatively low-temperature exhaust gas, that is, the exhaust gas at about 150 ° C. to about 100 ° C. Thus, there is an effect that an absorption refrigeration cycle having a refrigeration action can be provided. In addition, as a heat source,
In addition to exhaust gas, waste heat such as waste hot water and solar heat can also be used.

Further, even when the cooling chamber is not provided in the absorption chamber 62 and only the spraying device is provided, the refrigerant vapor generated in the regenerator 1 can be absorbed where the vapor pressure of the spraying absorption solution is low. Although this is an absorption refrigeration cycle slightly different from that described above, it has an effect of providing an absorption refrigeration cycle capable of providing a refrigeration action. That is, the solution flows into the absorption chamber 61 at a low temperature and a low pressure, and the temperature rises to almost the same pressure as the regeneration chamber 61 and the concentration decreases. In this case,
The heat exchanger 5 can be omitted.

Further, by providing means for exchanging heat between the dilute solution sent from the absorption chamber 62 to the regenerator 1 and the concentrated solution sent from the regenerator 1 to the regenerator 61, a cycle with higher efficiency can be realized.

In this embodiment, the regeneration chamber 61 and the absorption chamber 6
Although the case where the combination with 2 is one stage is shown, as the number of stages is increased to two stages and three stages, the amount of heat recovery from exhaust gas can be increased, and an absorption refrigeration cycle operating with lower temperature exhaust gas can be realized. . For example, in the case of two stages, there is an effect that heat can be recovered from exhaust gas of about 120 ° C. to about 70 ° C. to provide an absorption refrigeration cycle having a refrigeration action of about 0 ° C. That is, in the present embodiment, there is an effect that a device that generates a low temperature with a lower temperature heat source can be provided.

FIG. 10 is a cycle system diagram of still another embodiment of the present invention. Unlike the embodiment of FIG. 4, the first evaporator 3
A difference is that a heat exchanger is arranged in the first evaporator 3A so that cooling water for cooling can be obtained from A. Further, the second evaporator 3
B differs in that it is a vacuum heat storage layer 70. That is, a heat transfer tube through which cold water flows is arranged in the first evaporator 3A to cool the cold water, and the liquid refrigerant cools the second absorber 4B and self-evaporates in the first evaporator 3A. The liquid refrigerant of the first evaporator 3A is connected to the second evaporator 3B via the refrigerant flow control valve 71. The upper part of the vacuum heat storage layer 70 becomes a second evaporator 3B of the self-evaporation type, and the refrigerant discharged from the refrigerant pump 7B is sprayed by the second evaporator 3B. In addition, a low-temperature heat exchanger 72 is arranged at the lower part, and a stirrer 73 is also arranged. The low-temperature heat exchanger 72 is supplied with cold water cooled by the first evaporator 3A, and is connected to a load.

When the cooling load is light, the solution is sprayed on the second absorber 4B to cool the liquid refrigerant of the second evaporator 3B, and when the load is excessive, the solution sprayed on the vacuum heat storage layer 70 The refrigerant freezes by self-evaporation and accumulates in the tank.
In particular, when water containing a small amount of ethylene glycol or the like is used as the refrigerant, a part of the water is frozen in a needle shape and is deposited on the vacuum heat storage layer 70 with time. Therefore, the location of the low-temperature heat exchanger 72 is at a low temperature of about 0 ° C., and the cold water can be supplied to the load at a lower temperature, for example, 2 ° C. from 7 ° C. even when the load return is 12 ° C. Since the return temperature difference can be doubled from 5K to 10K, the power of the chilled water circulation pump can be reduced, the size of the chilled water piping can be reduced, and the equipment cost can be reduced.

When the cooling load is large, the heat of melting of ice in the vacuum heat storage layer can be used. Further, since the second absorber 4B is not operated, the first evaporator 3A can be operated at the maximum capacity, so that the cooling efficiency is high. That is, by operating the absorption chiller / heater during the night or in the early morning when the load is small and storing ice heat, the system can cope with the case where the load is excessive, and has the effect of reducing equipment costs.

The present system is also suitable for utilizing waste heat. That is, a waste heat source whose time is indefinite is stored in the form of ice and can be provided in a required time zone, so that there is an effect that intermittent waste heat that could not be used conventionally can be used.

[0053]

The freezing temperature of the mixed refrigerant can be reduced to 0 ° C. or less by mixing the absorbent with the evaporator spray liquid refrigerant, so that the absorption refrigerator can be widely used as a cooling heat source for refrigerated warehouses and the like. Become.

[Brief description of the drawings]

FIG. 1 is a cycle system diagram of an embodiment of the present invention.

FIG. 2 is a During diagram of the absorption refrigeration cycle of the embodiment of FIG.

FIG. 3 is a control system diagram of the absorbent mixing device of the embodiment of FIG.

FIG. 4 is a cycle system diagram of another embodiment of the present invention.

FIG. 5 is a cycle system diagram of still another embodiment of the present invention.

FIG. 6 is a cycle system diagram of still another embodiment of the present invention.

FIG. 7 is a sectional view of a heat transfer tube arrangement of an evaporator and an absorber according to an embodiment of the present invention.

FIG. 8 is a cycle system diagram of still another embodiment of the present invention.

FIG. 9 is a During diagram of the absorption refrigeration cycle of the embodiment of FIG.

FIG. 10 is a cycle system diagram of still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Regenerator, 2 ... Condenser, 3 ... Evaporator, 3A ... 1st evaporator, 3B ... 2nd evaporator, 4 ... Absorber, 4A ... 1st absorber, 4B ... 2nd absorber, 5 ... Solution heat exchanger, 6 ... solution circulation pump, 7, 7A, 7B ... refrigerant spray pump, 8 ... solution spray pump, 9 ... absorbent mixing means, 10 ... flow control valve, 11 ... blow amount control valve, DESCRIPTION OF SYMBOLS 12 ... Absorbent concentration sensor 13 ... Operation control device 14 ... Refrigerant conduit 15A ... Refrigerant tank, 15B ... Mixed refrigerant tank 16 ... Suction pipe 17 ... Refrigerant conduit 18 ... Refrigerant spray duct, 19 ... Pump 20 ... Cooling heat exchange Means 21: Refrigerated warehouse, 22: Air brine heat exchanger, 23: Heat pipe 24 ... Concentrated liquid conduit 25 ... Dilute solution conduit 26 ... Solution conduit, 27 ... Pump suction tube 28 ... Refrigerant blow tube, 29 ... Brine temperature Sensor, 0: Refrigerator control panel 31: High temperature regenerator, 32: Low temperature regenerator, 33: High temperature heat exchanger, 34: Refrigerant spray device, 35: Liquid refrigerant rebound prevention device, 36: Liquid surface area enlarging means, 37: Elimine 38, a refrigerant liquid level switch, 39, a circulating refrigerant temperature sensor, 40, a refrigerant conduit 41, a refrigerant spraying flow rate control valve, 51, a dropping device, 52, a tray, 53, a bleed pipe header, 53A, a bleed pipe, 54 extraction gas absorber 56 gas-liquid mixing pipe 57 gas-liquid separator 58 gas-liquid mixing pipe 60 extraction tank 61 regeneration chamber 62 absorption chamber 63, 64, 65 absorption liquid transport Means: 70: vacuum heat storage tank; 71: refrigerant flow control valve; 72: low temperature heat exchanger; 73: stirrer.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobumi Nobuto 502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. In-plant (72) Inventor Taisuke Kushima 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref.Hitachi, Ltd.Mechanical Research Laboratory Co., Ltd. References JP-A-59-18355 (JP, A) JP-A-3-95364 (JP, A) JP-A-4-64872 (JP, A) JP-A-55-31215 (JP, A) JP-A-5 -60435 (JP, A) JP-A-55-162565 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 15/00 303 F25B 15/00 F25B 15/00 306

Claims (3)

(57) [Claims] 1. A first evaporator, a second evaporator, a first absorber, and a first evaporator.
2 absorber, regenerator, condenser, liquid heat exchanger, solution circulation pump
And a pipe operatively connected to a refrigerant spray pump.
In an absorption refrigerator using a saline solution as an absorbent, heat of cooling the second absorber with the liquid refrigerant of the first evaporator is used.
While being arranged in an exchange relation, the second evaporator evaporates.
Refrigerant vapor is introduced into the second absorber, and the first vapor
The first suction in which the refrigerant vapor evaporated in the heater is cooled by cooling water.
A second evaporator introduced from the first evaporator to the second evaporator.
Arrange the absorbent mixing means in the liquid refrigerant flow path sent to the
The sprayed refrigerant of the second evaporator is a mixed refrigerant and exchanges heat with the heat medium.
And at least two regenerators that recover heat from the exhaust heat source
One of them communicates with the condenser and the effluent from the regenerator
The regenerator for reheating the liquid is connected to the concentration absorber group.
An absorption refrigerator. 2. A first evaporator, a second evaporator, a first absorber, and a second evaporator.
2 absorber, regenerator, condenser, liquid heat exchanger, solution circulation pump
And a pipe operatively connected to a refrigerant spray pump.
In an absorption refrigerator using a saline solution as an absorbent, heat of cooling the second absorber with the liquid refrigerant of the first evaporator is used.
While being arranged in an exchange relation, the second evaporator evaporates.
Refrigerant vapor is introduced into the second absorber, and the first vapor
The first suction in which the refrigerant vapor evaporated in the heater is cooled by cooling water.
A second evaporator introduced from the first evaporator to the second evaporator.
Arrange the absorbent mixing means in the liquid refrigerant flow path sent to the
The sprayed refrigerant of the second evaporator is a mixed refrigerant and exchanges heat with the heat medium.
And at least two or more regenerator groups recover heat from the exhaust heat source.
One of which communicates with the condenser and the flow of the regenerator
The regenerator for reheating the discharged solution is connected to the concentration absorber group.
And the absorbent in the liquid refrigerant flow path sent to the evaporator.
Arranging the mixing means, the sprayed refrigerant of the evaporator is a mixed refrigerant
An absorption refrigerator characterized by heat exchange with a heat medium. 3. A first evaporator, a second evaporator, a first absorber, and a first evaporator.
2 absorber, a regenerator, a condenser, Ekinetsu交 exchanger, the solution circulation Pont
And a pipe operatively connected to a refrigerant spray pump.
In an absorption refrigerator using a saline solution as an absorbent, heat of cooling the second absorber with the liquid refrigerant of the first evaporator is used.
While being arranged in an exchange relation, the second evaporator evaporates.
Refrigerant vapor is introduced into the second absorber, and the first vapor
The first suction in which the refrigerant vapor evaporated in the heater is cooled by cooling water.
A second evaporator introduced from the first evaporator to the second evaporator.
Arrange the absorbent mixing means in the liquid refrigerant flow path sent to the
The sprayed refrigerant of the second evaporator is a mixed refrigerant and exchanges heat with the heat medium.
The evaporator tube bank and absorber tube bank where the mixed refrigerant is sprayed
Characterized by alternately arranging and.