JPH07139844A - Absorption refrigerator - Google Patents

Abstract

PURPOSE:To provide an absorption freezer capable of being utilized for freezing at low temperature of about 0 deg.C. CONSTITUTION:In an absorption freezer wherein it includes a piping for connecting evaporators 3A, 3B having a group of heat transfer tubes, absorbers 4A, 4B, a regenerator 1, a condenser 2, a solution circulation pump 6, and a refrigerant spray pump 7 and taking an aqueous salt solution as an absorber, a refrigerant including the absorber mixed thereinto is sprayed to a group of heat transfer tubes of the evaporators 3A, 3B. Accordingly, the absorber is mixed into an evaporator spray liquid refrigerant with absorber mixing means so that mixed refrigerant freezing temperature becomes 0 deg.C or lower and hence a utilization range of the absorption freezer as a cooling/heating source for freezing warehouses, etc., are widened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-refrigerant absorption refrigerating machine, and more particularly to an absorption refrigerating machine suitable for use at a low temperature of about 0 ° C to 5 ° C such as refrigerating warehouses and storing vegetables.

[0002]

2. Description of the Related Art Conventionally, as a method for generating a low temperature of 0 ° C. or lower, there is an absorption refrigerator using a refrigerant having a boiling point of 0 ° C. or lower such as Freon R22 and ammonia. However, Freon R
Reference numeral 22 is a refrigerant that is inconvenient for protecting the ozone layer and is a refrigerant whose use should be restricted in the future, and ammonia is a toxic refrigerant. Furthermore, since the pressure of the regenerator is higher than atmospheric pressure, a strong container is required, and due care is required in handling, it is not popular in Japan, which is a country with a narrow population density.

On the other hand, the absorption refrigerator using water as a refrigerant is extremely safe because the pressure of the regenerator is vacuum, and is widely used as a heat source machine for building air conditioning. The structure is basically such that a regenerator, condenser, evaporator, absorber, liquid heat exchanger, solution circulation pump, etc. are operatively connected by piping, and a hygroscopic salt such as lithium bromide is used as an absorbent. ing. In the regenerator, the absorbent solution is heated by a heat source H such as a combustion gas of city gas to boil, and the generated refrigerant vapor (steam) 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, sprayed on the heat transfer tube and evaporated at about 4 to 6 ° C, and the cold water flowing in the tube is cooled by the latent heat of evaporation to cool the cold water at about 7 ° C. Is obtained and is circulated to the places that require cooling.

A related example of this type is disclosed in Japanese Patent Application Laid-Open No. 5-93555.

[0005]

The above-mentioned conventional techniques cannot be used for refrigeration requiring a low temperature of about 0 ° C. because water as a refrigerant is frozen. That is, when water, which is a refrigerant, is sprayed onto the tube group of the evaporator 4 under the evaporating pressure of 0 ° C. or less, the refrigerant itself is frozen because the latent heat of evaporation is taken from the refrigerant itself, and the refrigerant on the heat transfer tubes is frozen. The cycle could not be constructed because it did not flow down.

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

[0007]

The above object is provided with a pipe having an evaporator having a heat transfer tube group, an absorber, a regenerator, a condenser, a solution circulation pump and a refrigerant spray pump operatively connected, In an absorption refrigerating machine using an absorbent, the refrigerant dispersed in the heat transfer tube group of the evaporator is achieved by mixing the absorbent.

Further, the above-mentioned object is provided with a pipe operatively connecting a first evaporator, a second evaporator, a first absorber, a second absorber, a regenerator, a condenser, a solution circulation pump and a refrigerant spray pump, In an absorption refrigerator using an aqueous salt solution as an absorbent,
The first evaporator is arranged in a heat exchange relationship for cooling the second absorber, and the refrigerant vapor evaporated in the second evaporator is introduced into the second absorber and evaporated in the first evaporator. Refrigerant vapor is introduced into the first absorber cooled by cooling water, the absorbent mixture means is arranged in the second evaporator,
This is achieved by allowing the sprayed refrigerant to exchange heat with the heat medium with a mixed refrigerant.

Further, the above object is to operate the first evaporator, the second evaporator, the first absorber, the second absorber, the regenerator, the condenser, the liquid heat exchanger, the solution circulation pump, and the refrigerant spray pump. In an absorption refrigerating machine, which has a pipe connected to, and uses an aqueous salt solution as an absorbent, it is arranged in a heat exchange relationship for cooling the second absorber with the liquid refrigerant of the first evaporator, and
The refrigerant vapor evaporated in the evaporator is introduced into the second absorber, the refrigerant vapor evaporated in the first evaporator is introduced into the first absorber cooled by cooling water, and from the first evaporator, This is achieved by disposing an absorbent mixing means in the liquid refrigerant flow path sent to the second evaporator and allowing the sprayed refrigerant of the second evaporator to exchange heat with the heat medium as the mixed refrigerant.

Further, the above object is to provide a first evaporator, a second evaporator, a first absorber, a second absorber, a high temperature regenerator, a low temperature regenerator, a condenser, a liquid heat exchanger, a solution circulation pump, a refrigerant spray. -In an absorption refrigerator having a pipe operatively connected to a pump and using an aqueous salt solution as an absorbent, cold water is generated from the first evaporator, and cold water is generated from the second evaporator from the first evaporator. This is achieved by producing a colder brine than that produced and connecting cold water of two different temperatures to the load side.

Further, the above object is to provide a first evaporator, a second evaporator, a first absorber, a second absorber, a high temperature regenerator, a low temperature regenerator, a condenser, a liquid heat exchanger, a solution circulation pump, a refrigerant spray. -In an absorption refrigerator having a pipe in which a pump is operatively connected and using an aqueous salt solution as an absorbent, while being arranged in a heat exchange relationship for cooling the second absorber with the liquid refrigerant of the first evaporator or cold water. The refrigerant vapor evaporated in the second evaporator is introduced into the second absorber, and the refrigerant vapor evaporated in the first evaporator is introduced into the first absorber cooled with cooling water, The absorbent mixing means is arranged in the liquid refrigerant flow path sent from the first evaporator to the second evaporator, and the sprayed refrigerant of the second evaporator causes heat exchange with the heat medium by the mixed refrigerant. Cold water is generated from the evaporator and the first steam is generated from the second evaporator. Thereby generating a low-temperature brine than is produced by the vessel, it is accomplished by.

[0012]

When the absorbent is mixed with the liquid refrigerant generated in the condenser and introduced into the second evaporator, the boiling point of the mixed refrigerant rises,
On the other hand, since the freezing temperature is also lowered, it has the property of not freezing even at 0 ° C or lower. Therefore, the mixed refrigerant sprinkled on the heat transfer tube group in the second evaporator does not freeze even if the evaporation temperature becomes 0 ° C. or lower, flows down on the heat transfer tube group, and the cooled medium flowing in the heat transfer tube, For example, the antifreeze liquid (brine) can be cooled to supply cold brine at about 0 ° C.

Here, since the adsorbent mixing means is arranged in the refrigerant spray duct of the evaporator, the boiling point of the mixed refrigerant and the freezing temperature detecting means are used to grasp the freezing temperature decrease and the boiling point increase of the mixed refrigerant, and the cooling medium is cooled. Compared with the temperature detected by the temperature sensor, the concentration of the absorbent in the mixed refrigerant is reduced by opening the control valve to lower the pressure equilibrium temperature inside the machine and bring the freezing temperature closer to 0 ° C. By opening it, the concentration is controlled densely to raise the pressure equilibrium temperature inside the machine to a high temperature, and the freezing temperature is lowered to a temperature lower than 0 ° C. to control the difference in heat exchange temperature due to the rise in the boiling point of the mixed refrigerant, It can be controlled to increase the amount of heat exchange.

The first evaporator is arranged in a heat exchange relationship for cooling the second absorber, and the refrigerant vapor evaporated in the second evaporator is introduced into the second absorber and evaporated in the first evaporator. Refrigerant vapor is introduced into a first absorber cooled by cooling water, and an absorbent mixing means is arranged in a second evaporator,
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 with the cooling water of about 32 ° C. obtained in a normal cooling tower or the like. It is possible to construct a cycle 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 Duhring diagram of FIG. The symbols in the figure are the operating points of the cycle and correspond to the components. As is clear from the figure, when the pure water refrigerant is used as the refrigerant of the first evaporator as in this embodiment, the evaporation temperature can be about 20 ° C., and the heat exchange temperature difference between the absorption temperature of the second absorber and about 35 ° C. There is an effect that the value 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 10K from the absorption temperature of about 35 ° C of the second absorber.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
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. It is equipped with piping that is operatively connected. The regenerator 1 is provided with heating means H for heating and boiling the absorbent solution with steam or combustion gas of city gas. Refrigerant vapor (steam) 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 to be condensed and liquefied to become a liquid refrigerant.
The liquid refrigerant generated in the condenser 2 passes through the liquid refrigerant conduit 14 and the cooling heat exchange means 20 for the second absorber 4B of the first evaporator 3A.
It is sprayed on and evaporated, and the refrigerant vapor is guided to the first absorber 4A. Further, the latent heat of vaporization cools the second absorber 4B via the cooling heat exchange means 20. The non-evaporated refrigerant in the first evaporator 3A is held in the lower refrigerant tank 15A. The bottom portion 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 arranged so that the refrigerant serves as a mixed refrigerant on the heat transfer tube group of the second evaporator 3B. The mixed refrigerant is sprinkled. The non-evaporated mixed refrigerant is stored in the mixed refrigerant tank 15B, is again sucked by the refrigerant spray pump 7 and is 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 exchange means 22 of the refrigerating warehouse 21 by the pump 19 to cool the air in the refrigerating warehouse 21 and again to the second evaporator 3
It flows into the heat transfer tube group B.

On the other hand, the absorption liquid generated by generating the refrigerant vapor in the regenerator 1 and concentrated in the solution heat exchanger 5 exchanges heat with the dilute solution to reach a low temperature. Absorber 4
The first evaporator 3A is sprinkled on the cooling heat exchange means 20 of B.
It is cooled by the latent heat of vaporization of the refrigerant due to and absorbs the refrigerant vapor from the second evaporator 3B to become thin. This thinned absorption liquid is further fed to the first by the solution spray pump 8.
The first 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 in the tube.
The refrigerant vapor that has evaporated in the evaporator 3A is absorbed and further diluted to form a diluted solution, and the solution circulation pump 6 passes through the pump suction pipe 27, the diluted solution conduit 25, and the regenerator through the solution heat exchanger 5. Sent to 1. Further, the refrigeration load information is 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 concentration is high, the heat input is increased, and when the brine concentration is low and the refrigeration load is small, the heat input is limited.

The cycle is configured as described above.
Here, the absorbent mixing means 9 is a solution conduit 26 that connects the dilute solution conduit 25 and the refrigerant spray duct 18, the flow control valve 10 disposed in the solution conduit 26, and the refrigerant spray duct 18 and the first. 1 liquid refrigerant blow pipe 28 which communicates with the absorber 4A, a blow amount control valve 11 arranged in the liquid refrigerant blow pipe 28, a liquid refrigerant absorbent concentration sensor 12 arranged in the refrigerant spray duct 18, Brine outlet temperature sensor
29, the arithmetic and control unit 13.

Further, the cooling heat exchange means 20 is the second absorber 4
B is a means for exchanging heat between B and the first evaporator 3A, and is composed of a horizontal heat pipe 23.
The refrigerant is condensed inside the pipe 23, and the liquid refrigerant is evaporated on the side of the first evaporator 3A so as to exchange heat with the smooth.

Next, the operation will be described. When the liquid refrigerant generated in the condenser 2 is mixed with the absorbent and introduced into the second evaporator 3B, the boiling point of the mixed refrigerant rises, but the freezing temperature also lowers, so that it does not freeze even if it becomes 0 ° C or lower. Become a property. Therefore, the mixed refrigerant sprinkled on the heat transfer tube group in the second evaporator 3B does not freeze even if the evaporation temperature becomes 0 ° C. or less, flows down on the heat transfer tube group, and flows into the heat transfer tube. For example, the antifreeze liquid (brine) is cooled, and an effect of supplying low-temperature brine of about 0 ° C. is exerted.

Since the adsorbent mixing means 9 is arranged in the refrigerant spray duct 18 of the second evaporator 3B, as shown in FIG. 2, the adsorbent concentration is used as a means for detecting the boiling point and freezing temperature of the mixed refrigerant. The freezing temperature decrease and the boiling point increase 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 made thin by opening the blow amount control valve 11, the freezing temperature approaches 0 ° C., but the pressure equilibrium temperature in the evaporator can be made low, and the concentration is opened by opening the flow control valve 10. To control the decrease of the freezing temperature of the mixed refrigerant to the low temperature side and the decrease of the heat exchange temperature difference due to the increase of the boiling point of the pressure equilibrium temperature in the evaporator to increase the heat exchange amount. You can

In this embodiment, solenoid valves are used as the valves 10 and 11, but it is clear that the concentration of the absorbent in the mixed refrigerant can be controlled by proportional control by an electric valve or control by a small pump. is there.

Here, the first evaporator 3A and the second absorber 4B are used.
Is arranged in a heat exchange relationship for cooling the refrigerant, and the refrigerant vapor evaporated in the second evaporator 3B is introduced into the second absorber 4B,
Further, the refrigerant vapor evaporated in the first evaporator 3A is introduced into the first absorber 4A cooled by the cooling water, and the absorbent mixing means 9 is arranged in the second evaporator 3B so that the sprayed refrigerant is Since heat was exchanged with the heat medium with the mixed refrigerant, the first absorber 4A
The cooling water that cools the water is about 32
It becomes possible to cool with the cooling water of ℃, and the cycle structure can be realized 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 Duhring diagram of FIG. In the Duhring diagram, the vertical axis represents the pressure equilibrium saturation temperature of the pure refrigerant, and the horizontal axis represents the operating point of the cycle, which corresponds to the constituent equipment. As is apparent from the figure, when the refrigerant of the first evaporator 3A is pure water as in this embodiment, the evaporation temperature can be about 20 ° C., and the heat exchange with the absorption temperature of the second absorber 4B is about 35 ° C. This has the effect of making the temperature difference as large as about 15K. When 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 about 35 ° C of the second absorber 4B. 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 portions having the same symbols as in FIG. The difference between this embodiment and the embodiment shown in FIG. 1 is as follows.

This is that the refrigerant generation and absorbent concentration processes of the absorption refrigeration cycle are so-called parallel flow-2 heavy-effect absorption cycles. The regenerator 1 is composed of two parts, 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, and supplies the absorbing solution in parallel to each to heat the same. However, the 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 a refrigerant vapor, which is guided into the heat transfer tube of the low temperature regenerator 32 to be condensed and liquefied, and then 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 a refrigerant vapor, and the generated refrigerant vapor is guided to the condenser 2 and cooled by cooling water to be condensed and liquefied. Then, it is sent to the first evaporator 3A together with the refrigerant condensed in the heat transfer tube of the low temperature regenerator 32.
Further, a high temperature heat exchanger 33 for exchanging heat between the absorbing solutions coming in and out of the high temperature regenerator 31 is arranged to save the amount of heating to the high temperature regenerator 31. By improving the refrigerant generation and the absorbent concentration process, the refrigerant generated in the high temperature regenerator 31 and the refrigerant generated in the low temperature regenerator 32 can be obtained, and the refrigerant can be used for refrigeration in the evaporator. The thermal energy required to operate the refrigerator can be saved, and the refrigerant can be efficiently generated.

The first evaporator 3A is provided with the liquid refrigerant spray device 34 on the upper part and the reticulated liquid refrigerant jump-up prevention plates 35, 36, the refrigerant liquid level switch 38, and the refrigerant spray pump 7A on the lower part, and the first evaporator 3A is connected to the condenser 2 described above. The liquid refrigerant introducing pipe 14 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 in the heat transfer pipe of the second absorber 4B by the refrigerant spray pump 7A to cool the absorption liquid outside the pipe to raise the temperature. From the refrigerant spray device 34 to the first evaporator 3
By spraying in the space in A and evaporating a part of the liquid refrigerant, it becomes a low temperature liquid refrigerant again. The refrigerant liquid level switch 38 is a safety switch for preventing idling due to lack of liquid refrigerant in the refrigerant spray pump 7A. The refrigerant evaporated in the first evaporator 3A is absorbed by the absorbing 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 arranged at the refrigerant suction portion of the refrigerant spray pump 7A, and the rotation speed of the refrigerant spray pump 7A is controlled by the temperature signal to control the refrigerant flow rate. Since cooling of the 2 absorber 4B can be controlled, there is an effect that a cycle can be operated stably.

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

With the above-mentioned structure, first, the first evaporator 3A does not require a heat transfer tube, which has an effect of reducing the cost. 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 cooling of the absorbing solution flowing out of the tube can be efficiently cooled by the forced convection cooling in the tube. The second absorber 4B while saving the amount
It is possible to reduce the temperature difference between the absorption temperature and the refrigerant temperature of the first evaporator 3A, and it is possible to obtain the effect of operating the cycle with high efficiency. Further, since the pure refrigerant is evaporated in the first evaporator 3A and the mixed refrigerant is evaporated in the second evaporator 3B, the both do not mix, so that 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 portions having the same symbols as those in FIG. 4 have the same functions, and thus the description thereof is omitted. This embodiment and FIG.
Differences from the embodiment shown in are as follows.

The second by the refrigerant pump 7 of the first evaporator 3A
The refrigerant flowing in the heat transfer tube of the absorber 4B and circulated to the first evaporator 3A again, and a part of the liquid refrigerant is branched and passed through the flow rate control mechanism 41B, and further the refrigerant in which the absorbing liquid mixing means 9 is arranged. It is sprayed onto the heat transfer tube group of the second evaporator 3B via the spray duct 18. The heat exchanger 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 to the suction tube of the refrigerant spray pump 7 of the first evaporator 3A. Return via conduit 40. By disposing the second evaporator 3B at a position higher than that of the first evaporator 3A so that the liquid refrigerant hardly stays in the refrigerant tank 15B, the liquid level of the refrigerant is set to the first evaporator 3A. Only the refrigerant tank 15A was used. As a result, when the concentration of the absorbent in the circulating solution in the absorption refrigeration cycle is over-concentrated and crystallization is a concern, the refrigerant overflows from the first evaporator 3A to dilute the circulating solution. It is possible to prevent the crystallization of and to operate safely. Since the refrigerant in the first evaporator 3A is a mixed refrigerant, the difference in heat exchange temperature is reduced by the amount of the boiling point increase due to the admixture of the absorbent, but the mixed refrigerant spray pump in the second evaporator 3B is not required and the system is There is an effect that can be simplified. In addition, the refrigerant overflow from the second evaporator 3B is detected as a mixed refrigerant flow rate in an overflow pipe (not shown), and the flow rate control mechanism 41B is throttled so that the mixed refrigerant is excessive. 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 portions having the same symbols as those in FIG. 4 have the same functions, and therefore their explanations are omitted. The difference between this embodiment and the embodiment shown in FIG. 4 is as follows.

The refrigerant generation and absorbent concentration processes of the absorption refrigeration cycle are so-called series flow double effect absorption cycle, and the dilute solution of the second absorber 4B passes through the liquid heat exchanger 5 and the high temperature heat exchanger 33. Flowing 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 uses the latent heat of condensation of the refrigerant vapor generated in the high temperature regenerator 31 as a heat source. Sprayed on a group of tubes. The solution sprayed to the low temperature regenerator 32 is heated by the latent heat of condensation of the refrigerant vapor generated in the high temperature regenerator 31 to generate the refrigerant vapor, and is concentrated and passed through the liquid heat exchanger 5 to the first absorber 4A.
Return to.

As described above, the system is such that the high temperature regenerator 31 and the low temperature regenerator 32 are sequentially passed through the solution. On the contrary, there is a so-called reverse flow system in which a solution is circulated between the low temperature regenerator 32 and the high temperature regenerator 31, and these double-effect absorption refrigeration cycle flows are similar to the above-mentioned parallel flow, and the high temperature regenerator 31 is used. There is an effect that energy saving of external heat input can be achieved.

By the refrigerant pump 7 of the first evaporator 3A, the second
A refrigerant which flows through the heat transfer tube of the absorber 4B and circulates again to the first evaporator 3A, branches a part of the liquid refrigerant, and is provided with the absorbing liquid mixing means 9 via the refrigerant distribution amount control valve 41. It is sprayed onto the heat transfer tube group of the second evaporator 3B via the spray duct 18. The heat exchanger 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 is sent to the second absorber 4B to be 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 with the absorbent concentration controlled by the flow rate control valve 10 which is the absorbent mixing means 9 in response to the signal from the cooling medium temperature sensor-29. It Further, the amount of the refrigerant distributed to the second evaporator 3A depends on the refrigeration load, and the refrigerant distribution flow control valve 4
Since it is controlled by 1 and is sprayed, a large amount of the non-evaporated refrigerant does not flow out to the second absorber 4B to increase the heat loss. Further, there is an effect that the control system system of the absorbent mixing means 9 can be simplified.

In the present embodiment, the liquid refrigerant supplied to the second evaporator 3B is supplied by branching the liquid refrigerant of the first evaporator 3A from the discharge side of the refrigerant spray pump 7, but the liquid refrigerant from the condenser 2 is supplied. There is also a method of further simplifying the above by branching the flow path through the refrigerant spraying flow rate control valve 41 and the absorbent mixing means 9. Further, the absorbent mixing means 9 can be used as a simple orifice to mix a certain amount of the absorbent with the refrigerant so that the concentration of the absorbent in the mixed refrigerant becomes substantially constant to cope with it.

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 portions having the same symbols as those in FIG. 4 have the same functions, and thus the 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 arranged opposite to each other. A droplet lowering device 51 is arranged on the heat transfer tube group in each row, and a receiving tray 52 is arranged under the evaporator so that the unevaporated refrigerant can be collected and circulated and dropped again. A bleed tube 53A having a flat tube with a hole is arranged in the center of each two-row absorber tube group, is guided from the bleed tube header 53 to the bleed absorber 54, and is cooled with a refrigerant or low-temperature cooling water. The non-condensable gas is mixed and flows down through the liquid mixing pipe 56, separated into the non-condensable gas and the liquid by the gas-liquid separator 57, and the liquid is returned to the solution in the absorber by the gas-liquid mixing pipe 58 having a rising portion. The separated non-condensed gas is stored in the storage tank 60 via the gas rising pipe 59. Further, the extraction absorber 54 is the refrigerant pump 7B of the second evaporator 3B.
A liquid refrigerant branch pipe 55 branched from the discharge side of is connected and cooled.

With the above construction, 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. Particularly in the case of the present absorber operating in a low temperature vacuum, the ratio of the vapor flow pressure loss to the refrigerant evaporation pressure becomes large,
If the tube group is made larger, the movement of the refrigerant vapor is hindered, so the pressure loss becomes larger and the absorption refrigeration cycle that produces low temperature cannot be constructed. By disposing the evaporator and the absorber close to each other as disclosed in FIG. 7, the vapor flow pressure loss can be reduced, so that a low temperature absorption refrigeration cycle can be realized.

The presence of non-condensable gas in the absorber hinders the absorption of refrigerant vapor. Efficient extraction is essential for very low pressure absorbers. As in the present embodiment, by arranging the extraction pipe in the pipe group and guiding the extraction pipe to the extraction absorber, the non-condensable gas can be extracted efficiently, so 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 it to the suction of the solution pump of the absorber 4A, send it to the first absorber side, which has a relatively high pressure and is not easily affected by the non-condensed gas, and perform the bleeding process in the first absorber. This has the effect of simplifying the system by omitting the gas-liquid separator 57 and the air storage tank 60.

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

This embodiment will be described below. The regenerator 1 is composed of a vertical tube group, a fin orthogonal to the tube group, a cross fin tube heat exchanger composed of a lower header and an upper header, and high-temperature exhaust gas is guided to the fin group of the tube group of the regenerator 1. Then, the heat is exchanged with the absorption solution in the tube, the refrigerant vapor is generated to concentrate the solution, and the concentrated solution is sent to the regeneration chamber 61 by the solution transportation means 63. The regeneration chamber 61 is composed of a vertical tube group, fins orthogonal to the tube group, and a cross fin tube heat exchanger including 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 portion of the regeneration chamber 61 is connected to the absorption chamber 62. Here, the absorption chamber 62 is composed of a solution spraying device and a heat transfer tube group, and the cooling water whose temperature has risen by cooling the first absorber 4A and the condenser 2 is passed through the heat transfer tube. On the other hand, the diluted solution is sprayed from the second absorber 4B to the outside of the tube by the solution circulation pump 6 via the heat exchanger 5 and cooled, and the refrigerant vapor generated in the regeneration chamber 61 is absorbed and absorbed in the regeneration chamber 61. The liquid is further concentrated. The solution thinned by absorbing the refrigerant vapor in the absorption chamber 62 is sent to the regenerator 1 by the liquid transportation means 65. In addition, the absorption liquid concentrated in the regeneration chamber 61 is the solution transport means 64.
Flows into the first absorber 4A via the heat exchanger 5,
The solution spray pump 8 sprays 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 in the pipe of the second absorber 4B by the refrigerant circulation pump 7A to cool 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 sprayed by the mixed refrigerant spray pump 7B onto the heat transfer tube group of the second evaporator 3B so that the brine flows in the tube. The refrigerant vapor generated by heat exchange and evaporation is absorbed by the absorbing solution in the second absorber 4B. The absorbent concentration of the mixed refrigerant in the second evaporator 3B is controlled by the signal of the absorbent concentration sensor-12. The absorbent mixing means 9 is composed of a flow rate control valve 10 and a blow amount control valve 11. Is optimally controlled by.

FIG. 9 shows the absorption refrigeration cycle described above in a lithium bromide-water Duhring diagram. 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.
It operates at 0 ° C. and the absorption chamber 62 operates at 45 ° C. Further, the condenser 2 operates at 42 ° C., and the first evaporator 3A operates at about 1 ° C.
It operates at 0 ° C and the second evaporator operates at -5 ° C. As the absorbent, lithium chloride and other absorbents can be used in addition to lithium bromide, and the refrigerant can also be a water-based refrigerant containing a mixture of 2-ethylhexanol, methanol and the like.

As described above, since the regeneration chamber 61 and the absorption chamber 62 which are heated by the exhaust gas are arranged, the heat is recovered from the relatively low temperature exhaust gas, that is, the exhaust gas of about 150 ° C. to about 100 ° C., and about 0 ° C. There is an effect that an absorption refrigeration cycle having the above refrigerating action can be provided. As a heat source,
Besides exhaust gas, waste heat such as waste hot water and solar heat can also be used.

Further, even if the cooling pipe is not arranged in the absorption chamber 62 and only the spraying device is arranged, the refrigerant vapor generated in the regenerator 1 can be absorbed where the vapor pressure of the spraying absorbing solution is low. Although it is an absorption refrigeration cycle that is slightly different from the above, there is an effect that an absorption refrigeration cycle that can provide a refrigerating action can be provided. That is, in the absorption chamber 61, the solution flows in at low temperature and low pressure, the temperature rises to almost the same pressure as in 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.

Further, in this embodiment, the regeneration chamber 61 and the absorption chamber 6
The case where the combination with 2 is 1 stage is shown, but the heat recovery amount from exhaust gas can be increased as the number of stages is increased to 2 stages and 3 stages, and an absorption refrigeration cycle that operates with lower temperature exhaust gas can be realized. . For example, the two stages are effective in recovering heat from exhaust gas at about 120 ° C. to about 70 ° C. and providing an absorption refrigeration cycle having a refrigerating action at about 0 ° C. That is, the present embodiment has the effect of providing a device that generates a low temperature with a lower temperature heat source.

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
The difference is that a heat exchanger is arranged in the first evaporator 3A so that cold water for cooling can be obtained from A. Further, the second evaporator 3
B is different 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 in the first evaporator 3A is in communication with the second evaporator 3B via the refrigerant flow control valve 71. The upper part of the vacuum heat storage layer 70 becomes the second evaporator 3B of the self-evaporation system, and the refrigerant discharged from the refrigerant pump 7B is sprayed by the second evaporator 3B. Further, a low temperature heat exchanger 72 is arranged in the lower part, and a stirrer 73 is also arranged. Cold water cooled by the first evaporator 3A is passed through the low-temperature heat exchanger 72, and is connected to a load.

When the cooling load is light, the solution is sprayed to the second absorber 4B to cool the liquid refrigerant in the second evaporator 3B, and when the load is excessive, the liquid sprayed to the upper part of the vacuum heat storage layer 70. The refrigerant freezes by self-evaporation and accumulates in the tank.
In particular, when water with a slight addition of ethylene glycol or the like is used as a refrigerant, a part of the water freezes in a needle shape and accumulates on the vacuum heat storage layer 70 with time. Therefore, the temperature of the low-temperature heat exchanger 72 is as low as 0 ° C., and even if the load return is 12 ° C., the cold water can be supplied from the conventional 7 ° C. to a lower temperature, for example, 2 ° C. Since the return temperature difference can be doubled from the conventional 5K to 10K, the chilled water circulation pump power can be made small, and the chilled water pipe size can be made small, so that the facility 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 with the maximum capacity, so that the cooling efficiency is high. That is, by operating the absorption chiller-heater to store ice heat during nighttime or early morning when the load is low, the system can cope with an excessive load, and there is an effect that the equipment cost can be reduced.

The system is also suitable for utilizing waste heat. That is, since a waste heat source that is indefinite in time is stored in the form of ice and can be provided in a necessary time period, there is an effect that intermittent waste heat that cannot be used conventionally can be used.

[0053]

EFFECTS OF THE INVENTION By mixing an absorbent with an evaporator sprayed liquid refrigerant, it becomes possible to set the mixed refrigerant freezing temperature to 0 ° C. or lower, and the absorption refrigerator is widely used as a cooling heat source for a refrigerated warehouse or the like. Become.

[Brief description of drawings]

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

FIG. 2 is a Duhring 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 showing the arrangement of heat transfer tubes of the evaporator and the absorber according to the embodiment of the present invention.

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

9 is a Duhring 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]

 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, 12 ... Absorbent concentration sensor, 13 ... Arithmetic control device 14 ... Refrigerant conduit 15A ... Refrigerant tank, 15B ... Mixed refrigerant tank 16 ... Suction tube 17 ... Refrigerant conduit 18 ... Refrigerant spray duct, 19 ... Pump 20 ... Cooling heat exchange Means 21 ... Refrigerator warehouse, 22 ... Air brine heat exchanger, 23 ... Heat pipe 24 ... Concentrated liquid conduit 25 ... Dilute solution conduit 26 ... Solution conduit, 27 ... Pump suction pipe 28 ... Refrigerant blower pipe, 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 expanding means, 37 ... Elimine -38, ... Refrigerant liquid level switch, 39 ... Circulating refrigerant temperature sensor-40 ... Refrigerant conduit 41 ... Refrigerant distribution flow rate control valve, 51 ... Droplet lowering device, 52 ... Pan, 53 ... Bleed pipe header, 53A ... Bleed pipe, 54 ... Bleed air absorber, 56 ... Gas-liquid mixing pipe, 57 ... Gas-liquid separator, 58 ... Gas-liquid mixing pipe, 60 ... Bleed tank 61 ... Regeneration chamber, 62 ... Absorption chamber, 63, 64, 65 ... Absorption liquid transportation Means, 70 ... Vacuum heat storage tank, 71 ... Refrigerant flow rate control valve, 72 ... Low temperature heat exchanger, 73 ... Stirrer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobufumi Kousou, Inventor No. 502, Jinritsu-cho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Manufacturing Co., Ltd. Inside the Tsuchiura Plant (72) Inventor Taiji Hisashima 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Machinery Research Institute, Hiritsu Manufacturing Co., Ltd. In-house

Claims (12)

[Claims] 1. An absorption refrigerating machine, which comprises an evaporator having a heat transfer tube group, an absorber, a regenerator, a condenser, a solution circulation pump, and a pipe for connecting a refrigerant spray pump, and uses an aqueous salt solution as an absorbent. An absorption refrigerator, which is configured to spray a refrigerant mixed with an absorbent onto a heat transfer tube group of an evaporator. 2. The absorption refrigerating machine according to claim 1, wherein the absorbent mixing means is arranged in the middle of the refrigerant spray pipe to the evaporator, and the absorbent concentration detecting means of the spray mixed refrigerant is arranged. 3. A first evaporator, a second evaporator, a first absorber, a second absorber, a regenerator, a condenser, a solution circulation pump, a pipe for operatively connecting a refrigerant spray pump, and a salt. In an absorption refrigerator using an aqueous solution as an absorbent, the first evaporator is arranged in a heat exchange relationship for cooling the second absorber, and the refrigerant vapor evaporated in the second evaporator is transferred to the second absorber. The refrigerant vapor introduced and evaporated in the first evaporator is introduced into the first absorber cooled by cooling water, and the second vapor is introduced into the second absorber.
An absorption refrigerating machine, characterized in that absorbent mixing means is arranged in the evaporator, and the sprayed refrigerant exchanges heat with the heat medium in the mixed refrigerant. 4. A first evaporator, a second evaporator, a first absorber, a second absorber, a regenerator, a condenser, a liquid heat exchanger, a solution circulation pump, and a refrigerant spray pump are operably connected. In an absorption refrigerator having a pipe and using an aqueous salt solution as an absorbent, the refrigerant is placed in a heat exchange relationship for cooling the second absorber with the liquid refrigerant of the first evaporator, and the refrigerant evaporated in the second evaporator. The vapor is introduced into the second absorber, the refrigerant vapor evaporated in the first evaporator is introduced into the first absorber that is cooled by cooling water, and the first evaporator is introduced into the second evaporator. An absorption refrigerating machine characterized in that an absorbent mixing means is arranged in a liquid refrigerant flow path to be sent so that the sprayed refrigerant of the second evaporator exchanges heat with a heat medium by the mixed refrigerant. 5. A first evaporator, a second evaporator, a first absorber, a second absorber, a high temperature regenerator, a low temperature regenerator, a condenser, a liquid heat exchanger, a solution circulation pump and a refrigerant spray pump. In an absorption refrigerator having an operatively connected pipe and using an aqueous salt solution as an absorbent, cold water is generated from the first evaporator, and cold water is generated from the second evaporator from the second evaporator. An absorption chiller characterized in that cold water of different temperatures is connected to the load side to generate cold brine. 6. A first evaporator, a second evaporator, a first absorber, a second absorber, a high temperature regenerator, a low temperature regenerator, a condenser, a liquid heat exchanger, a solution circulation pump, and a refrigerant spray pump. In an absorption refrigerator having an operatively connected pipe and using an aqueous salt solution as an absorbent, while being arranged in a heat exchange relationship for cooling the second absorber with the liquid refrigerant of the first evaporator or cold water,
Refrigerant vapor evaporated in the second evaporator is introduced into the second absorber, and refrigerant vapor evaporated in the first evaporator is introduced into the first absorber cooled with cooling water. Absorbent mixing means is arranged in the liquid refrigerant flow path sent from the first evaporator to the second evaporator, and the sprayed refrigerant of the second evaporator causes the mixed refrigerant to exchange heat with the heat medium, thereby performing the first evaporation. An absorption refrigerating machine, wherein cold water is produced from a vessel, and brine having a temperature lower than that produced by the first evaporator is produced from the second evaporator. 7. An absorption refrigerating machine according to claim 4, wherein the amount of the adsorbent mixed by the adsorbent mixing means to the sprayed refrigerant of the evaporator is controlled by the signal of the absorbent concentration detecting means of the mixed refrigerant. . 8. An admixture amount of the adsorbent mixed with the evaporator-dispersed refrigerant is provided by a photodiode, an optical fiber, a light receiving element and an arithmetic element, and one end of the optical fiber is in the mixed refrigerant. Is controlled by the signal of the absorbent concentration detecting means of the mixed refrigerant which detects the change in the amount of reflected light by the refractive index difference with the mixed refrigerant and calculates the absorbent concentration of the mixed refrigerant to generate a signal. The absorption refrigerator according to claim 4, wherein the absorption refrigerator is a refrigerator. 9. A regenerator group having at least two regenerator groups for recovering heat from an exhaust heat source, one of which communicates with a condenser, and a regenerator for reheating a solution flowing out of the regenerator is a concentration absorber. The absorption refrigerator according to claim 4, wherein the absorption refrigerator is connected to the group. 10. A regenerator group for recovering heat from an exhaust heat source has at least two regenerators, one of which communicates with a condenser, and a regenerator for reheating a solution flowing out of the regenerator is a concentration absorber. An adsorbent mixing means is arranged in the liquid refrigerant flow path that is connected to the evaporator group and is sent to the evaporator, and the sprayed refrigerant of the evaporator causes heat exchange with the heat medium by the mixed refrigerant. Item 4. The absorption refrigerator according to item 4. 11. The absorption refrigerator according to claim 4, wherein the evaporator tube group row and the absorber tube group row in which the mixed refrigerant is dispersed are alternately arranged. 12. The absorption refrigerating machine according to claim 3 or 4, wherein the unmixed evaporated refrigerant of the second evaporator to which the mixed refrigerant is scattered is collected and connected to the solution pump suction pipe section through a pipe.