JPH038465B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention is directed to an absorption refrigerator in which an evaporator, an absorber, a low-temperature regenerator, and a condenser are configured in a vacuum tank, to improve refrigeration efficiency. The present invention relates to a single-double effect combination absorption refrigerator that is compact and can utilize natural energy or waste heat energy.

(b) Prior Art Conventionally, in a dual-effect absorption refrigerator 1 as shown in FIG. The liquid is divided at the branch point 6 on the outlet side of the heat exchanger 3, a part of which is sent to the low-temperature regenerator 7 and dispersed, and the remaining part is heated by the burner 9 of the high-temperature regenerator 8, where it is mixed with high-temperature refrigerant vapor. It becomes an absorbing liquid. The latter is separated into refrigerant vapor and concentrated absorption liquid by the gas-liquid separator 10, and the refrigerant vapor is introduced into the heat exchanger tubes 11 of the low-temperature regenerator 7. This refrigerant vapor heats the dilute absorption liquid distributed in the low-temperature regenerator 7 to evaporate the refrigerant, and the refrigerant vapor condenses while flowing through the heat transfer tube 11 and is led out to the condenser 12. In the condenser 12, refrigerant vapor from the low-temperature regenerator 7 is condensed in a heat transfer tube 13 through which cooling water flows, and this and the condensed refrigerant in the heat transfer tube 11 are supplied to an evaporator 14 and dispersed. It's becoming like that.

Such an absorption chiller 1 cannot be operated unless high energy is constantly supplied using the burner 9 of the high-temperature regenerator 8. The disadvantage is that it is not possible to perform energy-saving operation using heat energy or the like.

As a solution to these drawbacks, a single-double effect combination absorption refrigerator 2 as shown in FIG.
0 is proposed. This is the low temperature heat exchanger 21
A low-temperature heat source regenerator 22 that utilizes solar thermal energy is interposed in the pipeline from the low-temperature regenerator 7 to the low-temperature regenerator 7. In the case of combined operation, it is possible to perform double-effect operation with only the high-temperature regenerator 8 or to perform single-effect operation with only the low-temperature heat source regenerator 22.

When such an absorption chiller 20 is operated in a single/double effect combination, the dilute absorption liquid 5 of the absorber 4 sent to the low temperature heat exchanger 21 via the absorption liquid pump 2 is transferred to the low temperature regenerator 7. After being heated by a mixture of the intermediate liquid from the low-temperature heat source regenerator 22 and the concentrated absorption liquid from the high-temperature regenerator 8, the mixture is divided at the branch point 23 at the outlet of the low-temperature heat exchanger 21, and about 2/2 3 of the dilute absorption liquid is sent toward the next branch point 24, and about 1/3 of the remaining amount is introduced into the heat receiving side of the high temperature heat exchanger 25. Then, the dilute absorption liquid sent to the branch point 24 is divided there into two types: one to be introduced into the low temperature heat source regenerator 22 and the other to be introduced into the low temperature regenerator 7.

The dilute absorption liquid introduced into the high-temperature heat exchanger 25 is heated by the high-temperature concentrated absorption liquid returned from the high-temperature regenerator 8, and then introduced into the high-temperature regenerator 8, where the refrigerant is converted by combustion in a burner (not shown). The dilute absorption liquid is evaporated to become a concentrated absorption liquid, while the refrigerant vapor is introduced into the heat exchanger tube 11 of the low temperature regenerator 7. The dilute absorption liquid introduced into the low-temperature heat source regenerator 22 evaporates the refrigerant into an intermediate liquid by hot water heated by solar heat or the like in the heat transfer tube 26, and the refrigerant vapor is introduced into the low-temperature regenerator 7. Ru. The dilute absorption liquid sprayed in the low-temperature regenerator 7 is heated by the high-temperature refrigerant vapor in the heat transfer tube 11, evaporates the refrigerant, and becomes an intermediate liquid. Note that this intermediate liquid merges with the intermediate liquid of the low-temperature heat source regenerator 22 at the confluence point 27, and furthermore, after combining with the concentrated absorption liquid of the high-temperature regenerator 8 that has passed through the high-temperature heat exchanger 25 at the next confluence point 28. , are introduced into the heating side of the low temperature heat exchanger 21. Other operations are the same as those of the conventional example described above.

As can be seen from the above explanation, when dual-effect operation is performed using only the high temperature regenerator 8, in other words, the low temperature heat source regenerator 22 cannot be operated due to bad weather and the inability to utilize solar heat. In this case, about 1/3 separated at the branch point 24
The diluted absorption liquid simply passes through the low temperature heat source regenerator 22 and is returned to the confluence point 27 as the diluted absorption liquid.
In addition, if sufficient solar thermal energy or other waste heat energy can be used, low-temperature heat source regenerator 2
Only the refrigerant vapor evaporated from about 1/3 of the dilute absorption liquid introduced into the condenser 12 is sent to the high temperature regenerator 8.
Only the dilute absorbent liquid passes through.

When performing the single-double effect combination operation as described above in such a single-double combination absorption refrigerator 20, the amount of dilute absorption liquid introduced into the low-temperature heat source regenerator 22 is as small as about 1/3, and the low-temperature heat source Both the concentration and temperature of the intermediate liquid in the regenerator 22 become too high, making it impossible to effectively utilize natural energy and waste heat energy at low temperatures. Furthermore, since the temperature of the intermediate liquid in the low-temperature heat source regenerator 22 becomes too high, the intermediate liquid from the low-temperature regenerator 7 and the high-temperature concentrated absorption liquid from the high-temperature regenerator 8 are mixed to exchange low-temperature heat. Vessel 21
Even if heat is radiated from the absorber 4 to the low-temperature dilute absorption liquid 5, the temperature cannot be lowered to an appropriate level. Therefore, the temperature of the sprayed concentrated liquid in the absorber 4 becomes too high, and the effect of absorbing the refrigerant vapor from the evaporator 14 decreases, making it impossible to fully demonstrate the cooling capacity. Therefore,
In order to avoid this, the heat exchanger tube 29 of the absorber 4
It is necessary to operate the cooling water while lowering the temperature of the cooling water flowing therethrough, which has the disadvantage that the cooling tower (not shown) becomes large in size. Furthermore, during dual-effect operation, a portion of the dilute absorption liquid 5 only passes through the low-temperature heat source regenerator 22 and returns to the absorber 4 as it is, so no refrigeration cycle is formed and heat loss increases. In addition, the two branch points 23,
It is difficult to properly allocate the flow rate of the diversion in 24, and depending on various operating conditions such as low load, low cooling water, low temperature water, etc., the circulation amount of the dilute absorption liquid does not follow appropriately, and the pressure of the high temperature regenerator 8 Fluctuations increase.

In addition, when performing single effect operation, the low temperature regenerator 7
Since the amount of refrigerant vapor sent to the condenser 12 is as small as 1/3, when only the low temperature heat source regenerator 22 is operated, the refrigeration capacity is reduced, and when only the high temperature regenerator 8 is operated, double effect operation is possible. If you try to increase the same refrigerating capacity as when using a conventional method, the disadvantage is that you either have to increase the amount of heating or increase the size of the low-temperature heat source regenerator.

(c) Purpose of the Invention The present invention has been made to solve the above-mentioned problems, and it reduces the number of diversions of the dilute absorbent liquid to facilitate its flow distribution, and also improves the efficiency of the absorber during single-double effect combination operation. The purpose of the present invention is to provide a compact single-double effect combination absorption refrigerator with high refrigeration efficiency by lowering the temperature of the sprayed concentrated liquid returned to the refrigerator and further promoting the generation of refrigerant vapor in a low-temperature regenerator. shall be.

(d) Structure of the Invention The present invention is characterized in that a low-temperature heat source regenerator that generates refrigerant vapor using a low-temperature heat source is interposed in the dilute absorption liquid pipeline between the heat exchanger and the low-temperature regenerator. Furthermore, in addition to the above-mentioned configuration, the second invention also provides a high-temperature regenerator in a conduit between the heat exchanger and the high-temperature regenerator. The present invention is a single-double effect combination absorption refrigerating machine in which a high-temperature heat exchanger capable of heating a dilute absorption liquid from the absorber with a high-temperature concentrated absorption liquid is interposed.

(e) Examples The single-double effect combination absorption refrigerator of the present invention will be described in detail below based on examples thereof.

FIG. 3 shows a system diagram of a single/double effect combination absorption refrigerator 30 which is an embodiment of the present invention. This is the absorption refrigerator described in FIG. 1 with a low-temperature heat source regenerator 31 added thereto. After heating the dilute absorption liquid 5 from the absorber 4 in the heat exchanger 3, a part of it is guided to the low temperature regenerator 7 and the remainder to the high temperature regenerator 8, and the concentrated absorption liquid from the high temperature regenerator 8 and the low temperature regenerator are introduced. The intermediate liquid from 7 is returned to the heating side of the heat exchanger 3, mixed, and returned to the absorber 4 as a sprayed concentrated liquid, and between the heat exchanger 3 and the low-temperature regenerator 7. A low-temperature heat source regenerator 31 is interposed in the dilute absorption liquid pipe line 32 to generate refrigerant vapor by utilizing natural or waste heat energy such as solar heat introduced from the outside through a heat transfer tube 33. Note that two pipe lines 34 and 35 are connected to lead out the refrigerant vapor and intermediate liquid in the low-temperature heat source regenerator 31 to the condenser 12 and the low-temperature regenerator 7, respectively.

The operation of the single/double effect combination operation with such a configuration is as follows.

First, the diluted absorption liquid 5 of the absorber 4 is supplied to the absorption liquid pump 2.
After being heated, the diluted absorption liquid is introduced into the heat exchanger 3 , and after being heated, it is divided at a branch point 6 at its outlet, and approximately 1/2 of the diluted absorption liquid is introduced into the low-temperature heat source regenerator 31 via the diluted absorption liquid pipe 32 . There, it is heated via the heat exchanger tube 33, evaporates the refrigerant, and becomes an intermediate liquid. The refrigerant vapor is introduced into the condenser 12 via a line 34, and the intermediate liquid is transferred via a line 35 to the sparging device 3 of the low temperature regenerator 7.
Dispersed at 6. The remaining approximately 1/2 of the dilute absorption liquid separated at the branch point 6 is introduced into the high-temperature regenerator 8 via the pipe 37, where it is heated and becomes high-temperature refrigerant vapor and concentrated absorption liquid. is introduced into the separator 10.
Note that the distribution of the diluted absorbent liquid at the branch point 6 is confirmed in advance through experiments or the like, and the flow rate is adjusted by interposing an orifice or the like in the pipe line 37 or the diluted absorbent liquid line 32. The refrigerant vapor and the concentrated absorption liquid are separated in the gas-liquid separator 10, and the refrigerant vapor is introduced into the heat transfer tubes 11 in the low-temperature regenerator 7, and the intermediate liquid sprayed in the low-temperature regenerator 7 further converts the refrigerant into vapor. let The concentrated absorption liquid in the gas-liquid separator 10 is returned to the heat exchanger 3, where it is mixed with the intermediate liquid returned from the low-temperature regenerator 7, and is cooled by radiating heat to the dilute absorption liquid 5. , is sprayed as a spray concentrate via a pipe 38 in a spray device 39 of the absorber 4.

On the other hand, in single-effect operation using only the low-temperature heat source regenerator 31 and not using the high-temperature regenerator 8, a portion of the dilute absorption liquid from the absorber 4 simply passes through the high-temperature regenerator 8, and 1/2 of the remaining The diluted absorption liquid is transferred to the low temperature heat source regenerator 31.
will be introduced in In addition, double-effect operation using only the high-temperature regenerator 8 means that a portion of the dilute absorption liquid from the absorber 4 simply passes through the low-temperature heat source regenerator 31, and the remaining 1/2 of the dilute absorption liquid is heated to a high temperature. It is introduced into the regenerator 8.

In such an operation, the amount of dilute absorption liquid sent to the low temperature heat source regenerator 31 can be reduced to 1/2, so the amount of dilute absorption liquid sent to the low temperature heat source regenerator 31 can be reduced to 1/3 as described in the conventional example. Compared to the case, low temperature heat source regenerator 31
The temperature of the intermediate liquid inside the tank does not become too high, and natural energy and waste heat energy can be effectively utilized down to low temperatures. In addition, since the temperature of the sprayed concentrated liquid becomes low, the evaporator 1 in the absorber 4
The absorption effect of the refrigerant vapor from No. 4 into the sprayed concentrated liquid can be improved, and the capacity of the cooling tower (not shown) can be reduced in size. Further, even during dual-effect dedicated operation, all of the dilute absorption liquid that has passed through the heat exchanger 3 is circulated as part of the refrigeration cycle, so that heat loss is reduced. Furthermore, since the dilute absorption liquid branch point is set to one location, pressure fluctuations in the high temperature regenerator 8 can be kept small even under various load operations, and operation can be performed following an appropriate amount of dilute absorption liquid.

In addition, since the amount of intermediate liquid drawn out from the low temperature heat source regenerator 31 is large and its temperature can be lowered than in the conventional example, the logarithmic average temperature difference becomes large and the heat transfer area of the heat transfer tubes 33 can also be reduced. By the way, to explain theoretically how the heat transfer area of the low temperature heat source regenerator 31 can be made small, for example, if the amount of heat supplied is the same as in the conventional example, the heat transfer area of the low temperature heat source regenerator 31 is mainly It is determined by the inlet and outlet temperatures of the liquid supplying external thermal energy and by the logarithmic mean temperature difference between the inlet temperature of the dilute absorption liquid and the temperature of the derived intermediate liquid. In other words, the formula for determining the heat transfer area is HS=Q/(K・Δtm) where HS: heat transfer area K: heat transfer coefficient (approximately constant) Δtm: log average temperature difference Q: externally supplied amount of heat (constant), and if the logarithmic mean temperature difference Δtm increases,
This is because the heat transfer area can also be reduced.
Therefore, the low temperature heat source regenerator 31 can be downsized.

FIG. 4 shows a single/double effect combination absorption refrigerator 40 which is a different embodiment of the invention. In addition to the configuration of the invention described above, this is because the dilute absorption liquid from the absorber 4 is transferred to the pipe 37 from the heat exchanger 3 to the high temperature regenerator 8 by the high temperature concentrated absorption liquid of the high temperature regenerator 8. A high-temperature heat exchanger 41 that can heat the dilute absorption liquid 5 is interposed.

According to this, the dilute absorption liquid 5 from the heat exchanger 3
Before being introduced into the high-temperature regenerator 8, the refrigerant is further heated by the high-temperature concentrated absorption liquid from the high-temperature regenerator 8 in the high-temperature heat exchanger 41, so it is introduced into the high-temperature regenerator 8 in a state where refrigerant vapor is easily generated. will be done. The subsequent operation is no different from that of the invention described above.

Therefore, in addition to being similar to the above-described invention in terms of the refrigeration effect, the temperature of the dilute absorption liquid introduced into the high-temperature regenerator 8 can be further increased by interposing the high-temperature heat exchanger 41. Therefore, the fuel consumption of the burner 9 used in the high-temperature regenerator 8 can be reduced, and a large amount of refrigerant vapor can be generated in the high-temperature regenerator 8, so that the refrigeration effect can be further improved.

(f) Effects of the Invention As explained in detail above, the present invention provides a low temperature heat source regenerator that uses a low temperature heat source to generate refrigerant vapor in a dilute absorption liquid pipeline between a heat exchanger and a low temperature regenerator. Since the single-double effect combination absorption refrigerator is used, the intermediate liquid temperature of the low-temperature heat source regenerator can be lowered, and the low-temperature heat source regenerator can be made compact. In addition, the capacity of the cooling tower can be reduced, heat loss can be reduced by increasing cycle efficiency, and the number of branch points in the dilute absorption liquid system has been reduced, so it can be easily followed under various load operations. It can be operated with cooling efficiency. Furthermore, in addition to the above configuration, a different invention may include a pipe line between the heat exchanger and the high temperature regenerator, in which the dilute absorption liquid from the absorber is heated by the high temperature concentrated absorption liquid of the high temperature regenerator. Since a high temperature heat exchanger is provided, the refrigeration effect can be further improved.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a conventional double-effect absorption refrigerator, Fig. 2 is a system diagram of a conventional single-double-effect combination absorption refrigerator, and Fig. 3 is a system diagram of a conventional single-double-effect combination absorption refrigerator. A system diagram of an absorption refrigerator, FIG. 4 is a system diagram of a different invention. 3... Heat exchanger, 4... Absorber, 5... Dilute absorption liquid, 7... Low temperature regenerator, 8... High temperature regenerator, 3
0,40...Single and double effect combination absorption refrigerator,
31... Low temperature heat source regenerator, 32... Dilute absorption liquid pipe line, 37... Pipe line, 41... High temperature heat exchanger.

Claims (1)

[Claims] 1. After heating the dilute absorption liquid from the absorber with a heat exchanger,
A part of it is led to a low-temperature regenerator and the rest is led to a high-temperature regenerator, and the concentrated absorption liquid from the high-temperature regenerator and the intermediate liquid from the low-temperature regenerator are returned to the heating side of the heat exchanger and mixed. In an absorption refrigerator that returns liquid to the absorber, a low-temperature heat source regenerator that generates refrigerant vapor using a low-temperature heat source is interposed in the dilute absorption liquid pipeline between the heat exchanger and the low-temperature regenerator. This is a single/double effect combination absorption refrigerator. 2 After heating the diluted absorption liquid from the absorber with a heat exchanger,
A part of it is led to a low-temperature regenerator and the rest is led to a high-temperature regenerator, and the concentrated absorption liquid from the high-temperature regenerator and the intermediate liquid from the low-temperature regenerator are returned to the heating side of the heat exchanger and mixed. In an absorption refrigerator that returns liquid to the absorber, a low-temperature heat source regenerator that generates refrigerant vapor using a low-temperature heat source is interposed in the dilute absorption liquid pipeline between the heat exchanger and the low-temperature regenerator. In addition, a high-temperature heat exchanger capable of heating the dilute absorption liquid from the absorber with the high-temperature concentrated absorption liquid of the high-temperature regenerator is interposed in the pipeline between the heat exchanger and the high-temperature regenerator. A single/double effect combination absorption chiller featuring: