JPH04371764A - Absorbing device in ammonia-water absorption type freezer - Google Patents

Abstract

PURPOSE:To always keep a large air-liquid contact area, maintain a high substance moving speed, perform an effective absorption of ammonia vapor into weak ammonia solution and to make a small-sized ammonia-water absorption type freezer. CONSTITUTION:An ammonia-water absorption type freezer comprises a means 53 for forcedly mixing ammonia vapor with water solution of low ammonia concentration, and means 53 for agitating water solution of low ammonia concentration mixed with ammonia vapor. Ammonia vapor becomes fine bubble state within water solution of low ammonia concentration, resulting in that a bubble contact area is also increased and a superior absorption is carried out.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorber for an ammonia-water absorption refrigerating machine, and more particularly to an absorber for an ammonia-water absorption refrigerating machine constituted by a plate heat exchanger.

0002

[Prior Art] In general, absorption refrigeration cycles used in heat pumps, etc. have been put to practical use. One is a refrigeration cycle that uses water as a refrigerant and a lithium bromide aqueous solution as an absorbent, and the other is a refrigeration cycle that uses ammonia as a refrigerant and water as an absorbent. ing. In an ammonia-water absorption refrigerator using a refrigeration cycle using ammonia as a refrigerant and water as an absorbent, there is an absorber in which ammonia vapor is absorbed into an aqueous solution with a low ammonia concentration, and an absorber in which ammonia vapor is absorbed into an aqueous solution with a low ammonia concentration. a regenerator that superheats the absorbed liquid and separates and releases ammonia vapor;
It includes a condenser that cools and liquefies the ammonia vapor, and an evaporator that evaporates the ammonia solution to generate ammonia vapor and supplies the generated ammonia vapor to an absorber.

The refrigeration cycle of such an ammonia-water absorption refrigerator will be explained based on the system diagram shown in FIG. That is, as shown in FIG. 7, the ammonia-water system absorption refrigerator 10 includes an absorber 17 in which ammonia vapor is absorbed into an aqueous solution with a low ammonia concentration, and an absorbent liquid in which the ammonia vapor has been absorbed, which is superheated to produce ammonia vapor. A regenerator 11 that separates and discharges the ammonia vapor, a condenser 14 that cools and liquefies the ammonia vapor, and an evaporator 16 that evaporates the ammonia solution to generate ammonia vapor and supplies the generated ammonia vapor to the absorber 17. It is equipped with

[0004] Then, an aqueous solution with a high ammonia concentration (strong The solution) is heated by the heat source 12 by giving a heat amount Qg from the outside by burning gas or the like. The ammonia vapor containing a slight amount of water vapor generated in the regenerator 11 in this way is
It reaches the dephlegmator 13 via a flow path 20 provided between the regenerator 11 and dephlegmator 13.

[0005] Inside this dephlegmator 13 is a cooling pipe 3 which will be described later.
2 is provided, and a low-temperature strong solution flows in this cooling pipe 32. Therefore, the ammonia vapor that has flowed into the decentralizer 13 through the flow path 20 is transferred to the cooling pipe 3.
2 into ammonia vapor containing almost no water vapor and an aqueous solution containing a small amount of ammonia, and the aqueous solution containing a small amount of ammonia returns to the regenerator 11 via a flow path 21.

On the other hand, highly concentrated ammonia vapor containing almost no water vapor flows into the air-cooled condenser 14 through a flow path 22 provided between the condenser 14 and the decentralizer 13. The highly concentrated ammonia vapor that has flowed into the condenser 14 is cooled by operating the blower 40 provided in the condenser 14, and is condensed by radiating heat Qc to the outside, becoming liquefied ammonia.

[0007] The liquefied ammonia generated as a result of condensation in this manner flows into the precooler 15 via the flow path 23. It is further cooled in this precooler 15.
and the flow path 25 provided between the evaporator 16 and the flow path 2
The liquid is configured to flow into the evaporator 16 via a throttle valve 24 provided at the evaporator 16 . As shown in FIG.
2 is provided, and the heat medium flow path 43 is configured to communicate with an appropriate indoor unit 42. The liquefied ammonia that has flowed into the evaporator 16 is
It drips onto the outer surface of the cooling pipe 32 provided inside and evaporates,
The result is ammonia vapor.

On the other hand, the heat medium flowing through the flow path 43 is caused to flow through the cooling pipe 32 by a pump 69 provided within the steam flow path 43. The heat medium transported by the pump 69 in this manner is cooled by evaporation of the liquefied ammonia that has dropped onto the outer surface of the cooling pipe 32 while flowing through the cooling pipe 32 provided in the evaporator 16. It is something that

The heat medium cooled in this manner is conveyed through the flow path 43 by the pump 69 and reaches the indoor unit 42, where the blower 41 is operated to absorb heat (Qe) from the indoor air. , to cool the room as appropriate. On the other hand, the aqueous solution with a high ammonia concentration (strong solution) supplied to the regenerator 11 is heated by the heat source 12, and ammonia vapor is separated and released, resulting in an aqueous solution with a low ammonia concentration (weak solution). This weak solution is passed through a flow path 3 provided between the regenerator 11 and the solution heat exchanger 19.
8 to a solution heat exchanger 19, where the solution heat exchanger 19 exchanges heat with the strong solution supplied to the regenerator 11 via channels 36, 37. It is supplied to the liquid-cooled absorber 17 via a flow path 39 provided between the liquid-cooled absorber 19 and the absorber 17 (liquid-cooled absorber).

Further, a throttle valve 68 is provided in the flow path 39, and the weak solution is adiabatically expanded by passing through this throttle valve 68 and is supplied to the liquid cooling absorber 17. . The weak solution thus supplied to the liquid-cooled absorber 17 absorbs the ammonia vapor supplied from the precooler 15 to the liquid-cooled absorber 17 via the flow path 28 .

That is, a suitably constructed cooling surface section 34 is formed in this liquid cooling absorber 17, and a low temperature strong solution flows in this cooling surface section 34, and a weak solution is replaced by ammonia vapor. The structure is such that the low-temperature strong solution can cool down the heat of absorption generated when absorbing. Therefore, the weak solution is appropriately dropped onto the surface of the cooling surface section 34 in the liquid cooling absorber 17, and the absorbed heat generated when absorbing ammonia vapor is radiated to the strong solution flowing inside the cooling surface section 34. The solution, which has absorbed ammonia vapor in this way and is in an incompletely absorbed state, is transferred to the liquid cooling absorber 17.
and the air-cooled absorber 18 through a flow path 29 provided between the air-cooled absorber 18 and the air-cooled absorber 18, and when the blower 40 provided in the air-cooled absorber 18 operates, the absorbed heat Qa is released to the outside. Absorption will be completed.

[0012] The strong solution that has completed absorption in this way is
The solution is pressurized by a solution pump 31 disposed in a flow path 30 provided between the air-cooled absorber 18 and the demultiplexer 13, and is supplied to the demultiplexer 13. The strong solution flows through the cooling pipe 32 in the partial condenser 13 and cools the ammonia vapor supplied from the regenerator 11 through the flow path 20. Thereafter, the ammonia vapor is absorbed into the weak solution by flowing through the cooling surface section 34 through the flow path 33 provided between the dephlegmator 13 and the liquid cooling absorber 17. It absorbs heat and gets heated.

By being heated by the heat of absorption in this manner, boiling begins near the outlet of the flow path in the liquid cooling absorber 17, and the flow becomes a two-phase flow in which vapor and liquid are mixed. It passes through the passage 35 and reaches the solution heat exchanger 19. In this solution heat exchanger 19, the regenerator 11
By being further heated by the weak solution flowing in through the flow path 38 from It is configured to

[0014]

SUMMARY OF THE INVENTION Conventionally, there are various types of absorbers used in such water-ammonia absorption refrigerators. That is, for example, a surface absorption type absorber 44 shown in FIG. 8, a bubble absorption type absorber 45 shown in FIG.
, a packed bed absorption type absorber 46 shown in FIG. 10, and an irrigation liquid absorption type absorber 47 shown in FIG. 11.

For example, a surface absorption type absorber 44 shown in FIG.
The weak solution WS flows into the absorber main body 48 from the weak solution inflow hole 50 provided in the middle part in the height direction of the absorber main body 48, and the The structure is such that ammonia vapor V flows in from the inflow hole 52, and the weak solution WS flows in the upper part of the liquid in the absorber main body 48, and this weak solution WS
The ammonia vapor V flows so as to face the weak solution WS, and the ammonia vapor V is configured to be absorbed through the liquid surface of the weak solution WS.

The ammonia solution that has absorbed the ammonia vapor V becomes a strong solution SS and flows out from the outflow hole 51 provided at the lower end of the absorber body 48. The absorbed heat generated when the weak solution WS absorbs the ammonia vapor V is radiated to the cooling liquid flowing through the cooling pipe 49 disposed within the absorber main body 48.

Surface absorption type absorber 4 configured as described above
4, the contact between the weak solution WS and the ammonia vapor V is carried out only at the liquid surface, and the so-called absorption operation is configured such that contact is carried out only at the liquid surface,
The drawback was that it was not possible to increase the absorption area. In addition, in the bubble absorption type absorber 45 shown in FIG.
It is configured to be absorbed into the weak solution WS by being blown through the solution WS.

That is, the ammonia vapor V blown into the weak solution WS by the ejector 53 forms bubbles 67 within the absorber body 48 and is absorbed by the weak solution WS. The generated absorbed heat is absorbed by the absorber body 4.
Heat is radiated to a cooling medium flowing through a cooling pipe 49 disposed within the cooling pipe 8 . In the bubble absorption type absorber 45 configured in this way, the ammonia vapor V
Because it is absorbed on the surface of the air bubbles 67,
It becomes possible to form a large absorption area.

However, in such a bubble absorption type absorber 45, the bubbles 67 of the ammonia vapor V combine with each other and become larger during the absorption process, resulting in a decrease in the overall absorption area and a decrease in the absorption rate. It has the disadvantage that it decreases. In addition, bubbles 6 of ammonia vapor V generated
It was difficult to arrange the cooling pipes 49 at a close pitch so as to correspond to the number of cooling pipes 49.

Furthermore, in the packed bed absorption type absorber 46 as shown in FIG. The inflow hole 52 provided at the bottom of 48
The absorber body 48 is configured to be blown into the interior of the absorber body 48 from the inside. The ammonia vapor V blown from the lower part of the absorber body 48 in this way is absorbed by the weak solution WS sprayed from above the absorber body 48, and the strong solution SS accumulated at the lower part of the absorber body 48 flows out. It is configured so that it can flow outward from the hole 51.

The packed bed absorption type absorber 46 configured as described above has the advantage that the absorption area per unit volume is extremely large because the packed bed 54 is provided. There was a drawback in that it was difficult to arrange a cooling pipe inside the packed bed 54 for dissipating the absorbed heat generated when absorbing the ammonia solution V. Furthermore, in the perfusion absorption type absorber 47 as shown in FIG. The cooling liquid is configured to be able to be dropped onto each cooling pipe 49 through which the cooling liquid flows. The ammonia vapor V flows into the absorber main body 48 through the inflow hole 52 provided at the lower part of the absorber main body 48, while the weak solution WS flows from above the absorber main body 48 into the absorber main body 48. The ammonia vapor is dropped onto a plurality of cooling pipes 49, and the ammonia vapor is absorbed into a weak solution formed as a liquid film on each cooling pipe 49.

The absorbed heat generated when the ammonia vapor V is absorbed into the weak solution WS is radiated to the cooling liquid flowing through each cooling pipe 49. In this way, the weak solution WS that has absorbed the ammonia vapor V is sequentially dropped as droplets onto the cooling pipes 49 below, and at this time, the surface of each cooling pipe 49 and the surface of the wetted surface are replaced. ,
Configured to promote absorption and heat transfer.

[0023] Irrigation liquid absorption type absorber 4 constructed in this way
7 has the advantage that the absorbing surface where the weak solution WS absorbs the ammonia vapor V and the heat dissipating surface are on the same surface on the cooling pipe 49, and the replacement of the layer on the wetted surface is performed by dropping droplets. This is made possible by a simple method: However, in such a conventional irrigation absorber 47, a large number of cooling pipes 49 must be installed in parallel within the absorber main body 48, and the height of each cooling pipe during installation is limited. In addition, it is difficult to adjust the position of the absorber 47, and since the structure of the large number of cooling pipes 49 must be made pressure-resistant, the weight of the absorber 47 becomes extremely large.

[0024] In other words, all of the conventional absorbers have their own drawbacks, and it has been desired to reduce the installation area and weight of the absorber. By the way, as shown in FIG. 12, the refrigeration cycle of an absorption refrigerator includes a liquid side cycle (T
1→T2...→T9→T1) and the steam side cycle (T3
→T12, T13→...T16→T1), and the operation of merging these two cycles is absorption, and the point that greatly influences the performance of an absorption refrigerator is the temperature difference Δt between T8 and T4. .

[0025] This temperature difference Δt is due to the absorption and heat absorption while the high temperature weak solution flowing into the liquid cooling absorber is cooled between T8 and T9, while the strong solution which is the cooling medium is superheated between T2 and T4. This is the temperature difference that occurs during the exchange operation. The smaller this temperature difference Δt, the closer T4 approaches T6, and the temperature difference (T6-
T5) becomes smaller. Therefore, the smaller the temperature difference Δt, the smaller the input heat amount Qg of the regenerator, which increases the coefficient of performance of the absorption refrigerator.

Among the heat exchangers currently in use, there is a plate heat exchanger as a heat exchanger that can reduce the above temperature difference within a limited space. This type of plate heat exchanger has good heat transfer performance,
The heat transfer area and heat exchange amount per unit volume are large compared to other types of heat exchangers. Furthermore, it is extremely effective to use a plate heat exchanger in a refrigeration cycle in view of the drawbacks of conventional absorbers, namely, the installation area, size, and weight.

[0027] In addition, the key point in the absorption operation is to always create a large gas-liquid contact area between the weak solution and the vapor in order to dissipate the absorbed heat generated during absorption and to promote absorption.
The purpose is to increase the mass transfer rate by causing surface exchange. When looking at the structure of an absorber from this perspective, the one that satisfies these requirements is the perfusion absorption type absorber, but as mentioned above, it has the disadvantage of increasing the overall structure of the device. However, the disadvantage is that the high pressure energy required by a weak solution is not used effectively, but is used simply by a pressure reduction operation.

On the other hand, from the viewpoint of effectively using the pressure energy of a weak solution, the conventional bubble absorption type absorber is effective. From this point of view, it is conceivable to configure a bubble absorption type heat exchanger based on a plate type heat exchanger. As shown in FIGS. 13 and 14, such a bubble-absorbing plate-type liquid-cooled absorber 55 has air gaps 57a, An aqueous solution (weak solution) WS with a low ammonia concentration and an aqueous solution (strong solution) SS with a high ammonia concentration for cooling are alternately flowed into 57b, and ammonia vapor V is mixed into the aqueous solution WS with a low ammonia concentration. It is configured to release the absorbed heat generated by the absorption action to the aqueous solution SS having a high ammonia concentration.

That is, as shown in FIGS. 13 and 14, the ammonia vapor V is mixed into the weak ammonia solution WS by the ejector 53, and the ammonia vapor V is mixed into the weak ammonia solution WS by the ejector 53.
flows into a heat exchanger 99 configured by disposing them at predetermined intervals. This plate type liquid cooling absorber 5
5, a weak ammonia solution WS mixed with ammonia vapor V flows into the plate-type liquid-cooled absorber 55 from an inflow hole 61 provided below the plate-type liquid-cooled absorber 55. While flowing upward in the plate-type liquid-cooled absorber 55, the ammonia vapor V becomes a weak ammonia solution WS.
The absorbed heat generated at that time is released to the cooling solution 65 made of an aqueous solution SS with a high ammonia concentration flowing from the top to the bottom in the adjacent gap 57a.

As shown in FIG. 13, this cooling solution 65 with a high ammonia concentration is passed through the inflow hole 62 provided at the upper part of the plate heat exchanger 55 to the plate type liquid cooling absorber 5.
After flowing into the plate-type liquid cooling absorber 55 from above to below, it flows out from an outflow hole 63 formed at the lower end of the plate 56. The unabsorbed solution 66 that has absorbed the ammonia vapor V flows outward from an outflow hole 60 provided at the upper end of the plate-type liquid-cooled absorber 55.

By the way, in the plate-type liquid-cooled absorber 55 configured as described above, the ammonia vapor V sucked and mixed by the ejector 53 is in the form of fine particles, and a large number of minute bubbles 67 form a weak ammonia gas. It is present in the solution WS. Therefore, the total surface area of these bubbles 67 of ammonia vapor V is very large, the gas-liquid contact area is large, they are stirred by the ejection of the weak ammonia solution WS, and the mass transfer rate is high, so the absorption rate is also high. .

However, in such a conventional bubble absorbing plate type liquid-cooled absorber 55, although the cooling rate of the strong solution SS that radiates absorbed heat is constant, the weak ammonia solution WS As the bubbles 67 of ammonia V combine with each other and become larger, the surface area of the entire bubble becomes smaller and the gas-liquid contact area decreases. At the same time, since the ammonia vapor V is absorbed, the volume decreases, leading to a decrease in the flow rate of the solution, resulting in a decrease in the mass transfer rate, and as a result, there is a problem in that the absorption rate decreases. .

That is, when this state is shown graphically, as shown by the dotted line in FIG.
, where the temperature should be t9 are X9' and t, respectively.
9'. Therefore, in such a bubble absorption type plate heat exchanger, there is a two-phase flow of the bubbles 67 consisting of the solution flowing downstream in an unabsorbed state and ammonia vapor. In a phase flow, the heat transfer rate is higher on the liquid side, so the solution becomes more supercooled than the gas as it flows.

That is, if the absorption rate and cooling rate are the same as shown in the graph in FIG.
The same amount of heat should be exchanged for the heat exchange distance along the equilibrium line I, but the amount of heat released q1 and the amount of absorbed heat q
The state is supercooled by the difference ΔQ from 2. Therefore, the technical problem of the present invention is to effectively absorb ammonia vapor into a weak ammonia solution by always ensuring a large gas-liquid contact area and maintaining a high mass transfer rate in an ammonia-water absorption refrigerator. On the other hand, it is an object of the present invention to reduce the size of an ammonia-water absorption refrigerator.

[0035]

[Means for Solving the Problems] In order to solve such technical problems, the present invention provides means for forcibly mixing ammonia vapor into an aqueous solution with a low ammonia concentration, and a means for forcibly mixing ammonia vapor into an aqueous solution with a low ammonia concentration. The absorber is provided with a means for making bubbles made of ammonia vapor into a fine state by stirring the solution having a low ammonia concentration.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed explanation will be given below of an example in which the absorber for an ammonia-water absorption refrigerator according to the present invention is applied to an ammonia-water absorption refrigerator 10 shown in FIG. As shown in FIG. 1, the absorber used in the ammonia-water absorption refrigerator according to this embodiment is composed of a plate-type liquid-cooled absorber 70, and includes a liquid-cooled absorber main body 77 and an ammonia vapor V A weak ammonia solution W with a low ammonia concentration
Ejector 53 as a means for forcibly mixing the ammonia vapor V during S, a weak solution supply path 74 as a means for stirring a solution with a low ammonia concentration mixed with the ammonia vapor V, and an air-cooled absorber 18. ing.

In the absorber main body 77, like the plate type liquid cooling absorber 55 described above, a plurality of plates 54 are arranged at predetermined intervals, and the same as in the case shown in FIG. Then, a weak ammonia solution W is alternately applied to each gap defined by the plurality of plates 54.
S and a strong ammonia solution SS which is a cooling solution, and ammonia vapor V is passed through the weak ammonia solution WS.
Ammonia vapor V is mixed with ammonia weak solution W.
It is configured so that it can be absorbed by S.

Each plate 54 used in the absorber main body 77 is formed of a thin steel plate with a thickness of 0.3 to 1.0 mm, and the entire absorber main body 77 is formed of a brazed structure. There is. As shown in FIG. 1, from the generator 11 shown in FIG.
The weak ammonia solution WS supplied to the absorber 70 by
flows into the absorber body 77 from the inflow hole 61 provided in the absorber body 77. In this case, in this flow path 39, the ammonia vapor V supplied from the precooler 15 is forced into a weak ammonia solution by the ejector 53 provided immediately before the inlet hole 61 due to the high pressure of the weak ammonia solution WS. The weak ammonia solution WS is mixed with the solution WS, and the ammonia vapor V is mixed into the inflow hole 6 in the form of bubbles.
1 into the absorber body 77.

On the other hand, as shown in FIG. 7, the strong ammonia solution SS used for rectification in the partial condenser 13 is
3 into the absorber body 77. Then, this low-temperature strong ammonia solution SS flows into the absorber main body 77 from the inflow hole 62, and passes through each of the gaps defined by the plurality of plates 54, through which the weak ammonia solution WS flows. It flows down from above the absorber main body 77 through the flow path formed by the adjacent voids. The low-temperature strong ammonia solution SS that has flowed down inside the absorber main body 77 in this manner flows out to the outside of the absorber main body 77 through the outflow hole 63, and flows into the solution heat exchanger 19 shown in FIG.
leading to.

In the absorber body 77 used in the ammonia-water absorption refrigerator according to this embodiment,
A weak solution supply path 74 is provided as a means for stirring the weak ammonia solution WS containing the ammonia vapor V that has flowed in from the inlet hole 61 . This weak solution supply path 74 includes a main supply pipe 75 that is branched from the flow path 39 provided between the solution heat exchanger 19 and the absorber main body 77, and a main supply pipe 75 that is further branched from this main supply pipe 75. It consists of a plurality of branch pipes 76. The branch pipe 76 is arranged between the inflow hole 61 of the weak ammonia solution WS and the outflow hole 60 of the absorbing solution, into the flow path 73 of the weak ammonia solution WS containing the ammonia vapor V in the bubble state. opening 98 respectively
, 99.

That is, a certain distance L1 from the inflow hole 61
An opening 98 is provided at a distance L2 from the inflow hole 61, and an opening 99 is provided at a larger distance L2 from the inflow hole 61.
is provided. And these openings 98, 99
are provided at approximately equal intervals within the interval dimension L3 between the inflow hole 61 and the outflow hole 60. Therefore, in the absorber main body 77 used in the ammonia-water absorption refrigerator according to this embodiment, the flow path 39 is connected to the inlet hole 61.
The weak ammonia solution WS flowing into the absorber main body 54 via the ejector 5 provided in the flow path 39
3, the ammonia vapor V supplied from the precooler 15
is forcibly mixed into the weak ammonia solution WS. The ammonia vapor V mixed into the weak ammonia solution WS via this ejector 53 is in the form of bubbles, and the bubbles form extremely fine particles.
The surface area of the entire large number of bubbles made of ammonia vapor V is extremely large, and therefore the gas-liquid contact area is also extremely large.
Good absorption is achieved.

Furthermore, while flowing down the weak solution channel 73 toward the outflow hole 60, the high-pressure weak ammonia solution WS is composed of the main supply pipe 75 and a plurality of branch pipes 76, as described above. The ammonia weak solution WS that is ejected into the weak solution flow path 73 through the weak solution supply path 74 and mixed with the ammonia vapor V is stirred. Therefore, as the solution mixed with ammonia vapor V flows downstream through the weak solution flow path 73, even if the bubbles made of ammonia vapor V are combined and the diameter of the bubbles is increasing,
By being stirred again by the high-pressure weak solution WS supplied via the weak solution supply path 74 as described above, the bubbles made of ammonia vapor V become a large number of fine bubbles,
It becomes possible to secure a large overall bubble surface area.

Therefore, as shown in the graph of FIG.
In the absorber 70 used in the ammonia-water absorption refrigerator according to this embodiment, the absorption rate of the ammonia vapor V into the weak ammonia solution WS, and the cooling rate with the strong ammonia solution SS as the cooling solution. was found to be almost in equilibrium. In other words, as shown in the graphs of FIGS. 1 and 2, when line A indicating the absorption state advances a certain distance L from the origin of the graph, it gradually falls below line C indicating the cooling state, but after a certain distance from the origin At the position L1, the temperature exceeds the line C indicating the cooling state again, and the amount of absorbed heat increases.

After that, a line A showing the absorption state in the same way
falls below line C indicating the cooling state, but line C indicating the cooling state again at the position of distance L2 from the origin.
, the amount of absorbed heat increases. These facts mean that, as shown in FIG. 1, the inflow hole 98 is opened at a portion separated by a predetermined distance L1 from the inflow hole 61, and the inflow hole 98 is opened at a portion separated by a predetermined distance L2 from the inflow hole 61. Since the inflow hole 99 is opened in the inflow hole 99, the high pressure weak ammonia solution W flows through the inflow hole 98 and the inflow hole 99.
This shows that S flows into the flow path 73 to stir the solution and make the bubbles made of ammonia vapor mixed into a minute state.

FIG. 3 shows a second embodiment of the absorber used in the ammonia-water absorption refrigerator according to the present invention. The absorber 80 used in the ammonia-water absorption refrigerator according to this embodiment is a plate-type liquid-cooled absorber similar to the above embodiment, and includes an absorber main body 77 and a plurality of ejectors 53.
a, 53b, and an air-cooled radiator 87.

The absorber main body 77 has a plurality of plates 54 as in the above embodiment, and these plural plates 5
A strong ammonia solution SS, which is a cooling solution, and a weak ammonia solution WS, in which bubbles made of ammonia vapor V are mixed, are circulated in each of the gaps defined by 4,
The ammonia vapor V is absorbed into the ammonia weak solution WS, and the ammonia vapor V is absorbed into the ammonia weak solution WS.
The structure is such that the absorbed heat generated when absorbed by the liquid can be released into the cooling solution.

[0047] The liquid cooling absorber 80 according to this embodiment
In this case, the absorber main body 77 includes a first absorption part 77a,
A second absorbing portion 77b is provided. The first absorption section 77a includes a mixing section H consisting of an ejector 53a, a solution flow path B, and a cooling solution flow path D. The solution flow path B includes a solution heat exchanger 19 and an absorber main body 7 shown in FIG.
7, and a solution flow path 73a formed in the absorber main body 77.

The flow path 39 is connected to a solution inflow hole 61 provided at the lower end of the absorber main body 77, and a mixing section H consisting of an ejector 53a is provided within this flow path 39. . A flow path 28 provided between the precooler 15 and the absorber main body 77 shown in FIG. 7 is connected to this ejector 53a.
, the ammonia vapor V supplied by the flow path 28
is mixed into the weak ammonia solution WS flowing in the flow path 39 in the form of minute bubbles.

[0049] In this way, ammonia vapor V
The weak ammonia solution WS mixed in as minute bubbles flows into the absorber main body 77 from the inflow hole 61 and flows through the solution flow path 73a toward the outflow hole 95. On the other hand, the cooling solution flow path D is between the flow path 33 provided between the partial condenser 13 and the absorber main body 77 shown in FIG. A flow path 35 provided, an inflow hole 81 formed at the joint between the flow path 33 and the absorber main body 77, and an outflow hole 63 formed at the joint between the flow path 35 and the absorber main body 77. A cooling solution flow path 83a is formed between the cooling solution flow path 83a and the cooling solution flow path 83a.

Therefore, in the demultiplexer 13 shown in FIG.
The low temperature strong ammonia solution SS used for cooling flows into the absorber main body 77 from the inlet 81 via the flow path 33, and flows into the cooling solution flow path 8 formed in the absorber main body 77.
It circulates within 3a. At this time, the absorption heat generated when the ammonia vapor V in the bubble state is being absorbed into the weak ammonia solution WS flowing through the solution flow path 73a is radiated to the strong ammonia solution SS flowing through the flow path 83a. It is something that will be done.

[0051] In this way, the strong ammonia solution SS for cooling, which has received the absorbed heat, flows out of the absorber main body 77 from the outflow hole 63 and passes through the flow path 35 to the solution heat exchanger. It is configured to go towards 19. Also,
The second absorption section 77b includes a mixing section E, a solution flow path F, and a cooling medium flow path G.

The mixing section E includes an ejector 53b, and the solution flow path F includes a flow path 90 provided between the flow path 39 and the ejector 53b, and an outflow hole 95 for the weak ammonia solution. A flow path 89 provided between the ejector 53b, a flow path 97 provided between the ejector 53b and the absorber main body 77, and a flow path 97 provided between the ejector 53b and the absorber main body 77.
7 and an outflow path 96 for a strong ammonia solution SS.

A flow path 97 provided between the ejector 53b and the absorber main body 77 is connected to an inlet 82 for the ammonia weak solution provided in the absorber main body 77, and is also connected to the ammonia weak solution inlet 82 provided in the absorber main body 77. Strong solution outflow path 96
is connected to a solution outflow hole 60 opened at the end of a solution flow path 73b provided in the absorber main body 77. On the other hand, an air-cooled radiator 87 equipped with a blower 88 is provided in the coolant flow path G, and between the air-cooled radiator 87 and the absorber main body 77 are coolant flow paths 86 and 84. is provided. In this cooling medium flow path 84,
A pump 85 for supplying a cooling medium is provided, and is configured to be able to supply the cooling medium at a predetermined pressure.

The coolant flow path 86 is connected to the absorber body 77 via the coolant inflow hole 62, while the coolant flow path 84 is connected to the absorber body 77 through the coolant outlet 83. It is connected to the container body 77. A coolant flow path 83b is formed between the coolant inflow hole 62 and the coolant outflow hole 83. Therefore, in the plate-type liquid cooling absorber 80 according to this embodiment, the ammonia solution that has absorbed a certain amount of ammonia vapor V in the first absorption section 77a is transferred to the flow path 89 constituting the solution flow path F. and is guided to the ejector 53b. Also,
A flow path 90 provided between the ejector 53b and the flow path 39 is connected, and the weak ammonia solution WS flows into the ejector 53b through this flow path 90.
In the ejector 53b, the ammonia vapor flowing through the flow path 89 is mixed with the solution that has been absorbed to a certain extent.

In this way, the solution mixed with the weak ammonia solution WS flows from the inflow hole 82 through the solution flow path 73b via the flow path 97, and during that time, the absorption action is performed again. It is configured. That is, after the absorption action is performed once in the first absorption section 77a, the bubbles of ammonia vapor V that have become somewhat large in the solution are stirred by the weak ammonia solution WS being mixed in again by the ejector 53b, and are stirred again. The bubbles become microscopic, and a state is formed in which the ammonia vapor V is easily absorbed into the solution in the second absorption section 77b.

In this manner, the solution in which the ammonia vapor V has been efficiently absorbed becomes a strong ammonia solution SS and flows out of the absorber main body 77 from the outflow hole 60 and flows through the flow path 96.
It flows out through the process. Further, the absorbed heat generated when flowing through the solution flow path 73b is supplied into the absorber main body 77 via the coolant flow path 86, and
The heated cooling medium is cooled by the cooling medium that flows through the flow path 84 and is pumped by the pump 85 to the air-cooled radiator 87.
When the air blower 88 is activated, the amount of heat Qa is released to the outside.

Plate type liquid cooling absorber 8 according to this embodiment
0, a first absorption section 77a and a second absorption section 77b are provided, and the ammonia solution into which the ammonia vapor V has been mixed is stirred by again mixing the weak ammonia solution WS, Since it is configured to miniaturize the bubbles of ammonia vapor V, a large gas-liquid contact area can always be ensured.

Therefore, when comparing a conventional absorber or a plate-type heat exchanger configured such that ammonia vapor is simply absorbed into a weak solution, the plate-type liquid cooling absorption according to the second embodiment For the container 80, FIG.
It becomes possible to bring T4 shown in the graph of 2 closer to T10, and it also becomes possible to bring T9 closer to T2, and the amount of heat dissipated from T9 to T1 can be reduced by the decrease in the input heat amount in the regenerator 11. , it becomes possible to reduce the heat radiation area of the air-cooled absorber 18 shown in FIG. 7, and as a result, it becomes possible to downsize the entire structure of the absorption refrigerator.

The plate-type cooling absorber 80 according to this embodiment is configured to air-cool the cooling medium by providing an air-cooling radiator 87 having a blower 88 in the cooling medium flow path G. However, as shown in FIG. 4, a cooling tower 92 may be used instead of the air-cooled radiator 87 to cool the cooling medium, and the present invention is not limited to the above embodiment.

That is, as shown in FIG. 4, the cooling medium is supplied from the absorber main body 99 to the cooling tower 92 via the flow path 93, and after releasing the amount of heat Qa in the cooling tower 92, the cooling medium is supplied to the cooling tower 92.
2, is pressurized by a pump 94 provided in a flow path 91, and flows into the absorber main body 99 through the flow path 91. Although FIG. 7 shows a basic water-ammonia absorption refrigeration cycle (AX cycle), FIG. 6 shows an example of an improved cycle (GAX).

As shown in FIG. 5, the refrigerating capacity of the AX cycle is determined by the concentration of the ammonia aqueous solution from Xo to Xax
It is determined by the amount of latent heat of vaporization removed from the heat transfer medium when the ammonia vapor generated during the dilution is liquefied in the condenser and evaporated in the evaporator. In order to increase the refrigerating capacity in this cycle, it is possible to increase the amount of ammonia vapor generated by reducing the concentration of Xax, or in other words, increasing the outlet temperature of the regenerator.

However, as the regenerator outlet temperature rises, the amount of heat dissipated from the absorber and the amount of heat input to the regenerator also increase. Heat radiation other than that by the indoor unit is ineffective, and if this is used effectively within the cycle, the amount of heat radiated from the absorber and the amount of heat input to the regenerator will naturally decrease. Therefore,
In order to increase the efficiency within the cycle, it is necessary to utilize the temperature difference to exchange heat. In particular, if the heat absorbed by the absorber is utilized within the cycle, the amount of heat input to the regenerator can also be reduced. A cycle that can achieve this is the GAX cycle.

When comparing the AX cycle and the GAX cycle with the same amount of heat input to the regenerator, as shown in FIG. 6, the GAX cycle cools the ammonia aqueous solution supplied to the regenerator 11 before it is heated. This is achieved by emitting absorbed heat in the absorber 101 to heat the aqueous solution. As shown in FIG. 6, in the absorber 80 in this GAX cycle, as in the second embodiment shown in FIG.
02 and 103, respectively.

In each of the above embodiments, the ejector 53 is used as a means for forcibly mixing ammonia vapor into a solution with a low ammonia concentration, and the ammonia solution mixed with the ammonia vapor is stirred. Although the present invention has been described using an example in which the ejector 53 or the solution flow path 74 for supplying a weak ammonia solution is used as a means, the present invention is not limited to the above embodiments, and the internal structure of the plate heat exchanger may be changed. For example, an ammonia solution mixed with ammonia vapor may be configured to flow through an appropriate porous body, or an absorption enhancer may be added to the solution mixed with ammonia vapor to improve absorption efficiency. It is also possible to increase the

Furthermore, in each of the above embodiments, each plate 54 used in the absorber main body 77 is formed of a thin steel plate with a thickness of 0.3 to 1.0 mm, and furthermore, the entire plate is brazed. Since the absorber main body 77 is made of the same structure, manufacturing costs can be reduced and the weight of the absorber main body 77 can be reduced.

[0066]

Effects of the Invention The absorber used in the ammonia-water absorption refrigerator according to the present invention includes a means for forcibly mixing ammonia vapor into a solution with a low ammonia concentration, and a means for forcibly mixing ammonia vapor into a solution with a low ammonia concentration. Since the ammonia solution is equipped with a means for stirring a solution with a low temperature, the ammonia vapor bubbles in the ammonia solution can always be kept small, making it possible to always ensure a large gas-liquid contact area. .

As a result, by maintaining a high mass transfer rate, ammonia vapor can be effectively absorbed into the solution, and the entire absorption refrigerator can be downsized.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a first embodiment of an absorber for an ammonia water-based absorption refrigerator according to the present invention.

FIG. 2 shows the state in which ammonia is absorbed into a weak ammonia solution and the state in which ammonia is absorbed into a weak ammonia solution when the absorber of an ammonia water-based absorption refrigerator is operated in the first embodiment of the absorber of the ammonia water-based absorption refrigerator according to the present invention; It is a graph showing a comparison with a cooling state using a solution.

FIG. 3 is a conceptual diagram showing a second embodiment of the absorber of the ammonia water-based absorption refrigerator according to the present invention.

FIG. 4 is a conceptual diagram showing an absorber of an ammonia water system absorption refrigerator according to a third embodiment of the absorber of an ammonia water system absorption refrigerator according to the present invention.

FIG. 5 is a graph showing the relationship between temperature, pressure, and concentration in AX and GAX in an ammonia water-based absorption refrigeration cycle.

FIG. 6 is a conceptual diagram showing a fourth embodiment of the absorber of the ammonia water-based absorption refrigerator according to the present invention.

FIG. 7 is a conceptual diagram generally showing a refrigeration cycle of an ammonia water-based absorption refrigerator.

FIG. 8 is a conceptual diagram showing a surface absorption type absorber.

FIG. 9 is a conceptual diagram showing a bubble absorption type absorber.

FIG. 10 is a conceptual diagram showing a packed bed absorption type absorber.

FIG. 11 is a conceptual diagram showing a perfusion absorption type absorber.

FIG. 12 is a graph showing the refrigeration cycle of an absorption refrigerator in terms of the correlation between pressure and temperature.

FIG. 13 is a conceptual diagram showing a bubble absorption plate type liquid cooling absorber.

FIG. 14 is a sectional view showing a bubble absorption plate type liquid cooling absorber.

FIG. 15 is a graph showing a comparison between a state in which ammonia is absorbed by a weak ammonia solution and a state in which cooling is performed by a strong solution when the absorber is operated in a conventional bubble absorption plate type liquid-cooled absorber. .

[Explanation of symbols]

10 Ammonia-water absorption refrigerator 11
Regenerator 12 Heat source 13 Condenser 14 Condenser 15 Precooler 16 Evaporator 17 Absorber (liquid-cooled absorber) 18 Air-cooled absorber 19 Solution heat exchanger 20 Flow path 21 Flow path 22 Flow path 23 Flow path 24 Throttle valve 25 Flow path 26 Throttle valve 27 Flow path 28 Flow path 29 Flow path 30 Flow path 31 Solution pump 32 Cooling tube 33 Flow path 34 Cooling surface 35 Flow path 36 Flow path 37 Flow path 38 Flow path 39 Flow path 40 Air blower 41 Air blower 42 Indoor unit 43 Flow path 44 Surface absorption type absorber 45 Bubble absorption type absorber 46 Packed bed absorption type absorber 47 Irrigation absorption type absorber 48 Absorber body 49 Cooling pipe 50 Inflow hole 51 Outflow hole 52 Inflow hole 53 Ejector 53a , 53b Ejector 54 Packed bed 55 Plate-type liquid cooling absorber 56 Plates 57a, 57b Gap 61 Inflow hole 62 Inflow hole 63 Outflow hole 65 Cooling solution 66 Unabsorbed solution 67 Bubbles 68 Throttle valve 69 Pump 70 Plate-type absorber 73a, 73b Solution flow path 74 Weak solution flow path 75 Main supply pipe 76 Branch pipe 77 Absorber main body 77a First absorption section 77b Second absorption section 80 Plate type liquid cooling absorber 82 Inflow hole 83a Flow path 84 Flow path 85 Pump 86 Flow path 87 Air-cooled radiator 88 Blower 89 Flow path 90 Flow path 91 Flow path 92 Cooling tower 93 Flow path 94 Pump 95 Flow path 96 Ammonia strong solution outflow path 97 Flow path 98 Opening 99 Opening 100 Liquid cooling absorber 102 Liquid cooling absorption Container 103 Liquid cooling absorber A Line B showing the absorption state Solution flow path C Line D showing the cooling state Cooling solution flow path E Mixing section F Solution flow path G Cooling medium flow path H Mixing section I Equilibrium line Q Calorific value SS Ammonia strength Solution WS Ammonia weak solution V Ammonia vapor L Distance L1 Distance dimension L2 Distance dimension L3 Distance dimension L4 Distance dimension L5 Distance dimension L6 Distance dimension L7 Distance dimension L8 Distance dimension L9 Distance dimension L10 Distance dimension q1 Heat radiation amount q2 Absorbed heat amount △q Heat radiation amount The difference between and the amount of absorbed heat

Claims (1)

[Claims] Claim 1: an absorber in which ammonia vapor is absorbed into an aqueous solution with a low ammonia concentration; a regenerator in which the absorption liquid in which the ammonia vapor has been absorbed is heated to separate and release the ammonia vapor; and a regenerator that cools the ammonia vapor. a condenser that liquefies the ammonia solution; and an evaporator that evaporates the ammonia solution to generate ammonia vapor and supplies the generated ammonia vapor to the absorber, the absorbers being arranged at predetermined intervals. An aqueous solution with a low ammonia concentration and an aqueous solution with a high ammonia concentration for cooling were alternately flowed into each void formed between a plurality of plates, and ammonia vapor was mixed into the aqueous solution with a low ammonia concentration. In an ammonia-water system absorption refrigerating machine, which is constructed of a plate-type liquid-cooled absorber configured to cool the ammonia vapor by discharging the heat of absorption generated during the cooling process into an aqueous solution with a low ammonia concentration, the ammonia vapor is converted into an aqueous solution with a low ammonia concentration. An absorber for an ammonia-water absorption refrigerating machine, characterized in that an absorber for an ammonia-water system absorption refrigerator is provided, comprising means for forcibly mixing the ammonia vapor therein, and means for stirring an aqueous solution with a low ammonia concentration mixed with the ammonia vapor.