JP3434280B2 - Absorption refrigerator and its operation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerating machine, and more particularly to an absorption refrigerating machine suitable for constituting a large capacity machine and a method of operating the same.

[0002]

2. Description of the Related Art An absorption chiller is a chiller that uses water as a refrigerant and lithium bromide solution as an absorbent and heat as a driving source.
This is a refrigerator that is effective in utilizing waste heat. This absorption refrigerator has an evaporator, an absorber, a regenerator, and a condenser as main components, and the insides of the evaporator and the absorber are maintained in a high vacuum (6 to 7 mmHg in absolute pressure). The conventional absorption refrigerating machine is provided with a single evaporator and a single absorber, and these are formed to have a size suitable for the refrigerating capacity of the absorption refrigerating machine.

By the way, the refrigerating capacity of the conventional absorption refrigerator is 2500 RT at the maximum, but in order to increase the refrigerating capacity of this absorption refrigerator to, for example, 5000 RT, the capacity of the evaporator and the absorber of the single-unit structure is correspondingly increased. I have to improve. For that purpose, the evaporator and the absorber can be increased in size, but simply increasing the size of the evaporator and the absorber requires a correspondingly large installation space.

However, since the installation space of the absorption refrigerating machine is often limited, it is considered that it is often unsuitable to install a large single machine as described above. In addition, the larger the evaporator and the absorber, the worse their fabrication becomes, and the more difficult it becomes to carry and deliver them to the installation site.

FIG. 3 is a characteristic diagram showing the relationship between the steam consumption rate and the load of a conventional absorption refrigerator, and the reference symbol A in this figure is a rating point determined by the specifications of the absorption refrigerator. The load on A is approximately 100%. Further, as can be seen from the characteristic curve B that draws a convex arc downward in FIG. 3 through the rated point A, in the load range of about 40% or less, the steam consumption rate exceeds the level C of the rated point A. ing. As can be understood from FIG. 3, the absorption refrigerator has the following characteristics in the load range between the intersection D of the characteristic curve B and the level C and the rated point A:
The region where the characteristic curve B is the lowest, that is, approximately 60 to 8
The steam consumption rate is low in the 0% load range and the most efficient operation is possible. However, when the load is in the low load range of about 40% or less, the steam consumption rate needs to exceed the steam consumption rate at the rated point A,
The efficiency of the entire refrigerator tends to decrease.

The absorption refrigerating machine is a refrigerating machine having a partial load characteristic better than that of other refrigerating machines, such that the efficiency of operation in the partial load range exceeds the efficiency under the rated conditions, but it is still the above-mentioned. Thus, the efficiency in the low load range is lower than that in the rated condition. The reason is that the flow rate of the lithium bromide solution flowing in the refrigerator is too low in the operation in the low load region, and especially, the flow rate of the lithium bromide solution in the single-unit absorber is too low, It is believed that the absorber tube that it has becomes dry and its heat-transfer surface cannot be used effectively. As a result, in the low load region, the heat transfer area of the absorber becomes excessive with respect to the load, the absorption performance is reduced, and the efficiency of the entire refrigerator is reduced accordingly. Under such circumstances, when increasing the capacity of the absorption refrigerator, for example, it is required to improve the efficiency even in the operation in the low load range as described above.

[0007]

A first problem to be solved by the present invention is absorption refrigeration which can improve efficiency in a low load region and can suppress excessive disturbance of operation due to switching of operation modes. To learn how to operate the machine.
A second problem to be solved by the present invention is to improve efficiency in a low load region, suppress excessive disturbance of operation due to switching of operation modes, and further facilitate transportation with ease of manufacture. The aim is to obtain an absorption refrigerator that can be installed in a small space and is easy to deliver.

[0008]

A method of operating an absorption refrigerator according to the present invention is directed to an evaporator having a refrigerant nozzle for spraying a refrigerant,
A refrigerant pump for supplying a refrigerant to the nozzle, an absorber having a solution nozzle for spraying a concentrated lithium bromide solution to the refrigerant vapor generated in the evaporator, and a low-concentration lithium bromide solution in the absorber It is premised on an operating method of an absorption refrigerating machine having a plurality of evaporator / absorber systems each having a solution pump for supplying the regenerator to the regenerator side.

In order to solve the first problem, under a predetermined load or less, a part of the plurality of evaporator / absorber systems is used, and the other system is stopped and operated. In the load range larger than the predetermined load, the part of the system and at least part of the system that has been suspended are operated together, and the regenerator is accompanied by the switching of the operation mode. It is characterized in that the amount of heat source to be supplied to the regenerator is temporarily exceeded to the rated heat source consumption amount in the regenerator or more.

Further, the absorption refrigerating machine of the present invention includes an evaporator that has a refrigerant nozzle and sprays the refrigerant from the refrigerant nozzle on an evaporator tube through which cold water flows to evaporate and vaporize the refrigerant into refrigerant vapor. An absorber having a solution nozzle that absorbs the refrigerant vapor generated in the evaporator into a concentrated lithium bromide solution sprayed from the solution nozzle; and a bromide that has a low concentration by absorbing the refrigerant vapor. A regenerator that heats the lithium solution to evaporate the refrigerant in the solution to supply a concentrated lithium bromide solution to the absorber,
It is premised on an absorption refrigerating machine provided with a condenser that condenses and liquefies the refrigerant vapor generated in this regenerator to supply it to the evaporator.

In order to solve the second problem, the evaporator, a refrigerant pump for supplying a refrigerant to the refrigerant nozzle, the absorber, and a low-concentration lithium bromide solution in the absorber are added to the evaporator. Use multiple evaporator / absorber systems that have a solution pump to supply to the regenerator side, and use a part of the multiple evaporator / absorber systems under a specified load and operate while suspending other systems. And in a load range larger than the predetermined load, the switching valve for operating by using both the part of the system and at least part of the system that has been stopped, and the evaporator / absorber A chilled water temperature sensor that detects the outlet temperature of chilled water sent from the system to the cooling load, and the operation mode is switched by opening and closing the switching valve based on the outlet temperature detected by this sensor. It is characterized by comprising a controller to over turned over the rated heat consumption in heat sources amount, temporarily the regenerator is introduced into the regenerator Te.

In the present invention, the predetermined load can be arbitrarily set, and the evaporator / absorber system has two loads.
It can be implemented as long as the system or more, and the evaporator / absorber system does not have to have the same refrigerating capacity. Further, in the operating method of the present invention, the switching of the operating mode and the excessive input of the heat source amount due to this switching can be performed automatically or manually. Further, in the present invention, as a heat source supplied to the regenerator, in a configuration in which the regenerator is equipped with a burner, it can be used as fuel gas burned in this burner, and heat source steam generated by a boiler for district cooling and heating. Can be used. Therefore, in the former case, the excessive input of the heat source amount can be performed by increasing the opening of the fuel flow rate control valve provided in the injection line of the fuel gas to be injected into the burner of the regenerator, and in the latter case. This can be done by increasing the opening of the steam flow rate control valve provided in the input line of the heat source steam to be input to the regenerator. Furthermore, when the heat source amount is excessively input to the regenerator, a bypass flow path that bypasses the flow rate control valve is provided in the input line, and an opening / closing valve that normally maintains a closed state is installed in this flow path. Can also be done by fully opening with the controller.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic configuration diagram of an absorption refrigerator according to one embodiment. As shown in FIG. 1, the absorption refrigerator has first and second evaporator / absorber systems 1 and 2 capable of exhibiting the same refrigerating capacity, a regenerator, a condenser 3, and a low temperature heat exchanger 4. And a high-temperature heat exchanger 5 as main equipment, using water as a refrigerant, lithium bromide solution as an absorbent, and steam for district heating and cooling as a heat source, which is a large-capacity machine, For example, it is configured to exhibit a refrigerating capacity of 5000 RT.

As the regenerator, a double-effect type in which the regenerators are arranged in two stages is used for the purpose of increasing thermal efficiency and reducing heating energy. That is, the regenerator includes a high-pressure regenerator 6 that heats the dilute lithium bromide solution, and a low-pressure regenerator 7 that further heats the dilute lithium bromide solution using the high-temperature refrigerant vapor generated in the regenerator 6 as a heating source. Is equipped with.

The first evaporator / absorber system 1 includes an evaporator 11
, Absorber 12, refrigerant pump 13, and solution pump 14
It has and. The evaporator 11 and the absorber 12 are configured in the same shell (high vacuum container). An evaporator tube 15 (preferably using a multistage heat transfer tube group) is arranged in the evaporator 11. A film evaporation promoting tube is preferably used for this tube 15. Evaporator tube 15
Is supplied with cold water through a cold water inlet line (cold water distribution pipe) 16, and the cold water flowing through the evaporator tube 15 passes through a cold water outlet line (cold water distribution pipe) 17 and is attached to this line 17. Control valve 19 after 18
It is leaked to the outside through. The chilled water supplied to the chilled water inlet line 16 is used for a cooling device or the like (cooling load) of a building, and its temperature is raised to about 13 ° C. Cold water inlet line 16 (or cold water outlet line 17
But it's okay. ) Is attached with an operation valve 22 capable of opening and closing the flow path.

A refrigerant nozzle 20 is arranged in the evaporator 11 so as to face the evaporator tube 15, and a refrigerant (water, which is drawn up by a refrigerant pump 13 communicated with the bottom of the evaporator 11 through an on-off valve). ) Flows through the refrigerant line (refrigerant pipe) 21 and is supplied to the refrigerant nozzle 20. Since the evaporator 11 is configured in the high-pressure vacuum container as described above, the refrigerant nozzle 20 is formed by the spray film evaporation method.
The refrigerant sprinkled from the evaporator tube 15 toward the evaporator tube 15 is 4
Boiling at about 6 ° C to 6 ° C and evaporating. Therefore, the temperature of the cold water flowing in the evaporator tube 15 decreases according to the latent heat of vaporization given to the refrigerant, and the cold water flows out, for example, as 6 ° C. cold water. This chilled water is sent to the cooling load for use, whereby the temperature rises to about 13 ° C. and the chilled water inlet line 16,
Returned to 46.

Inside the absorber 12 is an absorber tube 25.
(It is preferable to use a multi-stage heat transfer tube group.). A film evaporation promoting tube is also suitably used for this tube 25. Cooling water of about 32 ° C. guided by a cooling water inlet line (cooling water inlet pipe) 26 is supplied to the absorber tube 25 through a control valve 27, and the absorber tube 25
The cooling water that has circulated through the cooling water flows out through the cooling water outlet line (cooling water outlet pipe) 28. Cooling tower water or water from another water source is used as the cooling water, and its inlet temperature is, for example, about 32 ° C. A solution nozzle 29 is arranged in the absorber 12 so as to face the absorber tube 25, and the concentrated solution of lithium bromide that is pressure-fed by at least one of the concentrated solution pumps 30 and 60 is supplied to the nozzle 29. It This supply is carried out from the concentrated solution pumps 30 and 60 through the operation valves 31 and 61, the low temperature heat exchanger 4, and then via the solution line (solution pipe) 32 to this line 32.
It is guided through the operation valve 33 provided in the.

The concentrated lithium bromide solution supplied to the absorber 12 is sprayed toward the absorber tube 25. The concentrated lithium bromide solution thus dispersed absorbs the refrigerant vapor formed in the evaporator 11 and flowing into the absorber 12, the concentration thereof is diluted, and the concentrated solution is collected at the bottom of the absorber 12.
Further, the reaction heat associated with this absorption is taken out by the cooling water flowing through the absorber tube 25. for that reason,
Due to this heat exchange, the temperature of the cooling water discharged to the cooling water outlet line 28 becomes, for example, about 40 ° C.

The dilute solution of lithium bromide having a reduced concentration and collected at the bottom of the absorber 12 is absorbed by the solution pump 14 connected to the bottom via an on-off valve.
It is pressure-fed to the outside, supplied to the low-temperature heat exchanger 4 via a solution line (solution pipe) 35, and further supplied from the heat exchanger 4 to the high-temperature heat exchanger 5. The lithium bromide dilute solution flowing through the high temperature heat exchanger 5 is supplied into the high pressure regenerator 6 through a solution line (solution pipe) 36.

The second evaporator / absorber system 2 has the same structure as the first evaporator / absorber system 1. That is, the evaporator 41, the absorber 42, the refrigerant pump 43, and the solution pump 44 are provided. The evaporator 41 and the absorber 42 are configured in the same shell (high vacuum container). Evaporator 3
An evaporator tube 45 (preferably using a multi-stage heat transfer tube group) is arranged in the inside of 1. A film evaporation promoting tube is preferably used as the tube 45. Cold water is also supplied to the evaporator tube 45 through a cold water inlet line (cold water distribution pipe) 46, and the cold water flowing through the evaporator tube 45 passes through a cold water outlet line (cold water distribution pipe) 47 to this line 47. After passing through the attached cold water pump 48, it flows out through the control valve 49. Cold water inlet line 46
Is the cold water inlet line 16 of the first evaporator / absorber system 1
It has been branched from. Therefore, this cold water inlet line 4
6 is also supplied with cold water whose temperature has risen to about 13 ° C. by being used as a cooling load. The cold water inlet line 46 (or the cold water outlet line 47) may be provided with an operation valve 52 capable of opening and closing its flow path.

The outlets of the chilled water pumps 18, 48 arranged in parallel with each other are merged after individually passing through the operation valves 19 or 49 and connected to a cooling load. A chilled water temperature sensor 66 for detecting an outlet temperature of chilled water passing through the merging line (circulation pipe) 65 on the downstream side of the merging point is attached. The detection information of the sensor 66 is supplied to the controller 67 that controls the entire absorption refrigerator. Based on the detection information of the cold water temperature sensor 66, the controller 67 determines whether the load of the absorption refrigerator is operating at a predetermined load or less.
Or, it has an operating load determining means for determining whether the vehicle is operating at a load larger than the predetermined load. or,
The controller 67 properly adjusts the heat source amount (heat source vapor amount in this embodiment) to be applied to the regenerator of the absorption refrigerator based on the cold water outlet temperature.

FIG. 2 is a characteristic diagram showing the relationship between the steam consumption rate and the load of the absorption refrigerator according to the present embodiment, in which the symbol A is a rated point determined by the specifications of the absorption refrigerator. The load at this rated point A is approximately 100%. or,
In the present embodiment, an upper limit of a low load range which is usually said, that is, a load slightly larger than a load of about 40%, for example, a load of about 50% is set as a reference value of whether or not the load is a predetermined load, The load of approximately 50% is automatically determined by the operating load determination means. In FIG. 2, E indicates a low load range of about 40% or less, and H indicates a load range from about 50% of the load point to the rated point A. Further, G in FIG. 2 shows a characteristic curve of the absorption refrigerator according to the present embodiment. This curve G has a curved portion G1 in the load range F and a low load at the load of approximately 50%. It is composed of a curved portion G2 in the area E. A characteristic curve represented by a curved line portion G3 indicated by a dotted line in FIG. 2 and a curved line portion G1 continuous with the curved line portion G3 indicates a characteristic when the absorption refrigerator of the present embodiment is operated in both lungs as described later. The curved line portion G2 indicates a characteristic curve when the absorption refrigerator of the present embodiment is operated in one lung on the low load region E side as described later.

Further, the evaporator tube 45 is provided in the evaporator 41.
The refrigerant nozzle 50 is arranged so as to face the evaporator 4 and
The refrigerant (water) pumped by the refrigerant pump 43, which is communicated with the bottom portion of the No. 1 through the on-off valve, flows through the refrigerant line (refrigerant pipe) 51 and is supplied to the refrigerant nozzle 50. Therefore, also in the evaporator 41, the refrigerant sprayed from the refrigerant nozzle 50 toward the evaporator tube 45 by the spray film evaporation method boils at around 4 ° C. to 6 ° C. and evaporates and evaporates. The temperature of the cold water flowing inside decreases according to the latent heat of vaporization given to the refrigerant, for example, 6 ° C.
It becomes cold water and is discharged. This cold water is sent to the cooling load and used for cooling, whereby the temperature rises to about 13 ° C. and is returned to the cold water inlet lines 16 and 46.

Inside the absorber 42 is an absorber tube 55.
(It is preferable to use a multi-stage heat transfer tube group.). A film evaporation promoting tube is also suitably used for this tube 55. Cooling water of about 32 ° C. guided by the cooling water inlet line 26 is supplied to the absorber tube 55 through a control valve 57, and the cooling water flowing through the absorber tube 55 passes through the cooling water outlet line 28. It is leaked to the outside. A solution nozzle 59 is arranged in the absorber 42 so as to face the absorber tube 55.
A concentrated solution of lithium bromide that is pressure-fed by at least one of the concentrated solution pumps 30 and 60 is supplied. This supply is carried out from the concentrated solution pumps 30 and 60 via the operation valves 31 and 61, the low temperature heat exchanger 4, and then via the solution line (solution pipe) 62 branched from the solution line 32 to this line. It is guided through an operation valve 63 provided at 62.

The concentrated lithium bromide solution supplied to the absorber 42 is sprayed toward the absorber tube 45. The concentrated lithium bromide solution thus dispersed absorbs the refrigerant vapor formed in the evaporator 41 and flowing into the absorber 42, and the concentration thereof is diluted and collected at the bottom of the absorber 42.
Further, the reaction heat due to this absorption is taken out to the outside by the cooling water flowing in the absorber tube 55. for that reason,
Due to this heat exchange, the temperature of the cooling water discharged to the cooling water outlet line 28 becomes, for example, about 40 ° C.

The dilute solution of lithium bromide, which has a reduced concentration and is collected at the bottom of the absorber 42, is absorbed by the solution pump 44 connected to the bottom through an on-off valve.
After being pressure-fed to the outside through the operation valve 64, it joins the solution line 35, is supplied to the low temperature heat exchanger 4 through this line 35, and is further fed from this heat exchanger 4 to the high temperature heat exchanger 5. Is supplied to. Concentrated solution pumps 30 arranged side by side,
The discharge ports of 60 are merged after individually passing through the operation valve 31 or 61 and are connected to the low temperature heat exchanger 4.

A charging line 70 for guiding high temperature steam (heat source steam) from a boiler (not shown) for district heating and cooling (not shown) is connected to the heat transfer tube 71 of the high-pressure regenerator 6, and this line 70 is connected to this line 70. A steam flow control valve 72 is attached. The steam flow rate control valve 72 is controlled in opening degree by using a motor as a power source.
The opening degree is adjusted to either the first opening degree or the second opening degree by 7. The first opening is an opening selected when the absorption refrigerator is in the rated operation state, and in this case, the circulation of the heat source steam in an amount commensurate with the rated steam consumption in the high pressure regenerator 6 is allowed. The second opening is an opening selected when the operation of the absorption chiller is switched from one-lung operation to double-lung operation, which will be described later, or vice versa. In this case, the high pressure regenerator 6 is used. In addition, a large amount of heat source steam that is excessively supplied in excess of the rated steam consumption is allowed to flow. Note that the first opening is not fixed, but includes opening adjustment for maintaining the chilled water temperature for the cooling load at the set temperature (6 ° C.) based on detection of the chilled water outlet temperature described later.

The heat transfer tube 71 of the high pressure regenerator 6 heats the dilute solution of lithium bromide supplied to the high pressure regenerator 6.
The heating evaporates part of the refrigerant from the dilute solution to form a solution in lithium bromide having a medium concentration. The lithium bromide medium-concentration solution thus obtained is supplied to the high-temperature heat exchanger 5 through the solution line (solution pipe) 73,
It is supplied to the low temperature heat exchanger 4 through the heat exchanger 5.

In the high temperature heat exchanger 5, there is a solution line 7 there.
The lithium bromide dilute solution supplied from the low temperature heat exchanger 4 side is heated using the high temperature lithium bromide medium concentration solution returned from 3. Thereby, while increasing the concentration of the solution, the heat recovery for cooling the medium concentration solution of lithium bromide is performed. The heat-recovered lithium bromide medium-concentration solution merges with the high-concentration lithium bromide concentrated solution flowing out from the low-pressure regenerator 7, and is supplied to the low-temperature heat exchanger 4 by the solution pump 30 or 60. And then supplied to at least one of the absorbers 12 and 42,
It is sprayed from the solution nozzle 29 or 59.

On the other hand, the refrigerant vapor evaporated in the high pressure regenerator 6 passes through a refrigerant line (solution pipe) 75 and the low pressure regenerator 7
Is supplied to the regenerator tube 76 of the
6 through a refrigerant line 77, and is supplied to a refrigerant nozzle 78 arranged above the condenser 3. The low-pressure regenerator 7 and the condenser 3 arranged above the low-pressure regenerator 7 are configured in the same shell (high-pressure vacuum container).

The low pressure regenerator 7 has its regenerator tube 76.
Has a solution nozzle 79 which is disposed to face the upper side of the low temperature heat exchanger 4 and the high temperature heat exchanger 5 and passes through a solution line (solution pipe) 80 drawn from between the low temperature heat exchanger 4 and the high temperature heat exchanger 5. The medium concentration solution of lithium bromide that has passed through the low temperature heat exchanger 4 is supplied. The solution nozzle 79 sprays a lithium bromide medium concentration solution on the outer surface of the regenerator tube 76. Therefore, the dispersed lithium bromide concentration solution is heated by the regenerator tube 76 in which the high-temperature refrigerant vapor generated in the high-pressure regenerator 6 is flowing. As a result, a part of the refrigerant contained in the medium-concentration solution is evaporated, and a high-concentration lithium bromide concentrated solution is produced.
Stored at the bottom of the. The concentrated lithium bromide solution in the low pressure regenerator 7 is sucked into the solution pump 30 or 60 through the solution merging line 81 and is supplied to the low temperature heat exchanger 4.

The solution outlet 6a of the high-pressure regenerator 6 is passed through the high-temperature heat exchanger 5 to join the solution merging line 81 (leading the concentrated lithium bromide solution obtained in the low-pressure regenerator 6). The solution line 90 is provided with a first flow rate control valve 91. Then, in the solution line 90, the first
A bypass flow path 92 that bypasses the flow rate control valve 91 is provided. It should be noted that the number of solution lines 90 is one, and the number obtained by adding the number of bypass flow paths 92 to this is the same as the number of the plurality of evaporator / absorber systems.
One or more bypass flow paths 92 are provided according to the number of evaporator / absorber systems. Then, in the bypass flow passage 92,
A second flow rate control valve 93 and an automatic opening / closing valve 94 are attached respectively. The opening adjustment of the first and second control valves 91 and 93 is executed based on an instruction from the controller 67,
By the adjustment, the flow rate of the refrigerant flowing in the refrigerator is adjusted to be appropriate. The automatic opening / closing valve 94 is also opened / closed based on an instruction from the controller 67.

The automatic on-off valve 94 has a low load region below the predetermined load (for example, 50% load is preferable when there are two evaporator / absorber systems having the same refrigerating capacity as described above). When the absorption refrigerator is operated by one lung on one side, it is closed and used, and when the absorption refrigerator is operated by both lungs in the load range H from the predetermined load to the rated point A, it is opened and used. To be done. In single lung operation, the evaporator / absorber system 1,
The absorption refrigerator is operated by using either one of the two and resting the other. In the load range H extending from the predetermined load to the rated point A, the double lung operation is performed, and in the double lung operation, the absorption refrigerator is operated using both the evaporator / absorber systems 1 and 2.

Inside the condenser 3, a condenser tube 82 to which cooling water is supplied by the cooling water inlet line 26 is provided. The condenser 3 has an absolute pressure of 55 mmHg (about 1
/ 14 atm). In this condenser 3,
The refrigerant supplied through the refrigerant line 77 and the refrigerant vapor evaporated in the low pressure regenerator 7 and flowing into the condenser 3 are
It is cooled and condensed by heat exchange with the cooling water flowing through the condenser tube 82 to become a refrigerant (water). This refrigerant is sent to the refrigerant line (refrigerant piping) 83 by gravity and the pressure difference.

The refrigerant line 83 is divided into two systems as shown in FIG. One branch refrigerant line 83a is provided with an operation valve 84 as a refrigerant supply valve to the evaporator in the middle thereof and is connected to one evaporator 11, and the other refrigerant line 8a.
3b is provided with an operation valve 85 as a refrigerant supply valve to the evaporator on the way, and is connected to the other evaporator 41. Therefore, the refrigerant condensed and liquefied by the cooling water in the condenser 3 is supplied to at least one of the evaporators 11 and 41, and then is supplied to the evaporators 11 and 41 by the refrigerant pump 13 or 43.
It is sprinkled towards the outer surface of the inner evaporator tube 15 or 45.

In the absorption refrigerator having the above structure,
Operation valves 22, 31, 33, 34, 52, 61, 63, 6
Reference numerals 4, 84 and 85 are switching valves used for switching between one lung operation and both lung operations by being opened / closed by using a motor as a power source.
9 is also used as a switching valve for switching between single lung operation and double lung operation. The automatic opening / closing valve 94 is also opened / closed by using the motor as a power source. It should be noted that although this absorption refrigerator is capable of heating operation, it is not related to the present invention, and therefore the description of operation during heating operation is omitted.

In the absorption refrigerator having the above structure, when the outlet temperature of the cold water flowing through the outflow line 65 detected by the cold water temperature sensor 66 is higher than the predetermined temperature, the load of the absorption refrigerator is higher than the predetermined load (50%). Is determined by the controller 67, and the absorption refrigerator is operated in the dual lung operation mode based on the command from the controller 67.

In this dual lung operation mode, each operation valve 22,
31, 33, 34, 52, 61, 63, 64, 84, 8
5 and the automatic open / close valve 94 and the like are held in an open state, the pumps 13, 14, 18, 30, 43,
44, 48, 60, and the operation of the condenser 3, the regenerators 6, 7, etc., the first and second evaporator / absorber systems 1 and 2 are used together, and the refrigerant and the absorbent are used in the refrigerator. The previously described cycle for is repeated. As described above, in the double lung operation using all the evaporator / absorber systems 1 and 2, the curve G in FIG.
1 and a characteristic curve formed by a smoothly continuous curve portion G3 at a load of 50% without forming an inflection point J, and exhibits a refrigerating capacity of up to 5000 RT. In this case, the operation can be performed most efficiently in the region where the load is approximately 60 to 80%.

When the outlet temperature of the cold water detected by the cold water temperature sensor 66 is lower than the predetermined temperature, the controller 6 determines that the load of the absorption refrigerator is lower than the predetermined load (50%).
7 makes a determination, and based on the command from the controller 67, the absorption refrigerator uses only a part of the plurality of evaporator / absorber systems and suspends the other evaporator / absorber systems. It is operated in the single lung operation mode.

In this single lung operation mode, the operation valves 22, 33, 34, 84, the control valves 19, 27 and the automatic opening / closing valve 94 related to the first evaporator / absorber system 1 are instructed by the controller 67. And the pumps 13, 14, 18, and 30 are stopped. On the other hand, the operation valves 52, 6 related to the second evaporator / absorber system 2
1, 63, 64, 85 and the control valves 49, 57 maintain the closed state, and the pumps 43, 4
4, 48, and 60 are kept in the operating state. As a result, the first evaporator / absorber system 1 is stopped and the single lung operation in which the second evaporator / absorber system 2 is used is executed.

Instead of this, the first evaporator / absorber system 1 is used based on a command from the controller 67, and the one-lung operation in which the second evaporator / absorber system 2 is stopped is performed. You can also In addition, the first and second evaporator
It is possible to switch between the above-described single lung operation and double lung operation by omitting each operation valve and control valve for any of the absorber systems 1 and 2, and in this case the valve The number of used refrigerators is reduced, and the refrigerator configuration can be simplified and the cost can be reduced. However, in the configuration in which each operating valve and control valve are provided in all of the evaporator / absorber systems to switch the operation mode as in the present embodiment, the first and second operation is performed every time the low load operation is performed. Since the evaporator / absorber systems 1 and 2 can be used alternately, only a part of the evaporator / absorber system is not always used, and it does not deteriorate faster than other systems. Excellent in high durability.

As described above, since the single lung operation is executed in the load range where the load is less than 50%, at this time, the regenerator 6,
Refrigerant flowing back from the 7 side toward the first and second evaporator / absorber systems 1 and 2 is supplied only to the second evaporator / absorber system 2. Along with this, the amount of refrigerant sprayed back to the evaporator 41 is kept constant, so that not only the performance of the evaporator 41 is not deteriorated, but also the absorber 4 paired with the evaporator 41.
The circulation rate of the lithium bromide solution for 2 is increased.

That is, in the absorption refrigerator, it is known that when the load decreases, the circulation amount of the lithium bromide solution in the absorption refrigerator decreases and the heat transfer area of the absorber also decreases. Absorber tube group (absorber tube) is loaded 100
Since it is designed to optimize the circulation rate of the lithium bromide solution in%, 50% as described above in this design.
When the circulation rate of the solution of lithium bromide drops below the load of 1, the operation is performed in one lung, and the supply of the lithium bromide solution to the one absorber 12 not used in this operation is stopped. Therefore, since all the lithium bromide solution circulating in the refrigerator is flowed to one tube group of the absorber 42 which is used in the single lung operation, the circulation of the lithium bromide solution to one tube group of the absorber 42 is performed. You can double the amount.

Therefore, the absorber tube 55 of the absorber 42 is prevented from being dried, and the heat transfer surface thereof can be used effectively, so that the absorption performance of the absorber 42 is prevented from being lowered, and the low load region is suppressed. It is possible to improve the efficiency of the refrigerator in a load range (a load range requiring a steam consumption rate higher than the level C at the rated point A and a load range F of about 40% or less in FIG. 2).

When changing the above operation mode,
For example, when a load variation of 45% to 55% is applied, the transition from double lung operation to single lung operation or vice versa may be repeated, resulting in lack of control stability. Therefore, in practice, for example, when the load increases to 50% or more, both lung operations are performed, and both lung operations are excessively maintained even when the load is 40% or less, and the load is 40% or less. Controller 6 so that it will shift to single lung operation for the first time
It is desirable to have a configuration in which it is controlled by 7. With such a configuration, chattering in control can be eliminated and stable control can be performed.

By the way, in the above-described single lung operation in the low load region, as the heat transfer area of the evaporator / absorber system used becomes half as compared with the double lung operation, this single lung operation is performed. As a result of the proof test, it was found that the lithium bromide solution flowing through the second evaporator / absorber system 2 used was increased and the concentration thereof became dark. However, the absorption refrigerating machine having the above-mentioned configuration is provided with the automatic opening / closing valve 94 of the bypass flow passage 92, which is provided in communication with the solution outlet 6a of the high-pressure regenerator 6 and bypasses the solution line 90 which joins the solution joining line 81. It can be closed at the time of lung operation and the solution flow rate can be appropriately throttled to match the circulating flow characteristics in the refrigerator with a partial load (low load). That is, the combined flow rate of the lithium bromide medium-concentration solution having a medium concentration is reduced with respect to the lithium bromide concentrated solution introduced to the solution joining line 81, and accordingly, the concentrated solution pump 60 sends the solution to the absorber 42. The concentration of the lithium bromide solution can be diluted. By adjusting the concentration of the lithium bromide solution in accordance with the decrease in the circulation amount of the lithium bromide solution, the amount of the lithium bromide solution for the second evaporator / absorber system 2 used during the single lung operation can be changed to the lithium bromide in the refrigerator. It can be improved to suit the concentration balance of the solution. Thereby, the efficiency of the absorption refrigerator can be improved.

As described above, the absorption refrigerating machine having the above-described structure shifts from the double lung operation to the single lung operation in the low load region, so that the evaporator 4 of the evaporator / absorber system used at that time is operated.
1 and the performance of the absorber 42 can be prevented, and the deterioration of the steam consumption rate can be prevented. The improvement of the steam consumption rate at such a partial load is shown by a curved line portion G2 in FIG.

As described above, the transition from the double lung operation to the single lung operation, or vice versa, is performed by the cold water temperature sensor 66 attached to the confluent line 65 through the confluent line 65 as described above. The temperature of cold water is detected, and it is determined whether or not it is in the low load region based on the detected temperature. Therefore, it is possible to easily determine the predetermined load set as the reference for the operation switching, and to perform the double lung operation or the single lung operation depending on the load based on the determination.

By the way, as described above, the absorption refrigerating machine in which the operation mode is automatically switched according to the load is provided with a plurality of evaporator / absorber systems, so that the transient operation accompanying the switching of the operation mode is caused. The present inventor has found a phenomenon in which the chilled water outlet temperature is likely to rise due to a significant disturbance in operation, that is, a decrease in refrigerating capacity.

That is, the distribution of the lithium bromide solution in this absorption refrigerator is adjusted and adjusted so as to be balanced at the time of rating. However, as described above, when operating in one lung in a low load range, the concentration of the lithium bromide solution is not uniform due to the influence of the load condition and the cooling water temperature at that time. One-sided evaporator
The concentration of the lithium bromide solution in the absorber included in the absorber system is likely to be different from the concentration of the lithium bromide solution in the absorber included in the other evaporator / absorber system that is stopped in one lung operation.

Therefore, at the stage of switching from single-lung operation to double-lung operation, the refrigerating capacity of the evaporator / absorber system that has been stopped until then is low. Easy to come down. As a result, the cold water outlet temperature may rise above a predetermined temperature, and the cold water supply commensurate with the cooling load may be impaired.

In both lung operations, the concentration of the lithium bromide solution in both systems 1 and 2 is proper, but the concentration of the lithium bromide solution in the regenerators 6 and 7 is low at this stage. Therefore, when the operation is switched from the double lung operation to the single lung operation, the dilution operation is performed. For this reason, the refrigerating capacity may decrease with the switching of the operation mode, and as a result, the cold water outlet temperature may rise above a predetermined temperature, impairing the supply of cold water commensurate with the cooling load.

However, in the absorption refrigerating machine having the above-mentioned structure, it is possible to prevent the refrigerating capacity from being excessively lowered due to the switching of the operation modes, and to raise the cold water outlet temperature in a short time.

That is, when the operation mode is switched by the controller 67 from the double lung operation to the single lung operation based on the detection of the cold water outlet temperature, or vice versa, the controller 6
At the same time, 7 controls the steam flow rate control valve 72 to the second opening degree to temporarily increase the amount of heat source supplied to the high pressure regenerator 7 through the charging line 70, that is, the amount of heat source steam.
In the configuration of the present embodiment, this excessive charging may be increased by about 25% of the rated steam consumption of the high pressure regenerator 7. The degree of excessive input of the heat source amount is appropriately determined in consideration of the characteristics of the absorption refrigerator and the characteristics of the boiler.

In this way, the heat source vapor is automatically and temporarily input to the high-pressure regenerator 6 in an excessive amount, thereby giving a large amount of heat to the internal cycle of the absorption refrigerator to temporarily increase the concentration of the lithium bromide solution. Can be increased. for that reason,
In any operation mode switching, it is possible to suppress an excessive decrease in the refrigerating capacity that accompanies it. Therefore, although the rise phenomenon of the cold water outlet temperature due to the operation mode switching is not eliminated, the time until the raised cold water outlet temperature returns to the steady temperature (6 ° C.) can be shortened. By the way, in the present embodiment, it can be set to about 5 minutes or less (this is a degree that does not cause a substantial problem on the cooling load side).

The cold water outlet temperature is measured by the cold water temperature sensor 66.
Therefore, when the chilled water outlet temperature returns to the steady temperature due to the excessive addition, the controller 67
Controls the steam flow control valve 72 from the second opening to the first opening to prevent the heat source steam from being excessively charged.

Further, the controller 67 is provided therein with a timer for limiting the maximum time of excessive input of the heat source amount, and this timer counts a predetermined time limit (for example, 30 minutes) at the same time when the operation mode is switched. To start. Therefore, even if the chilled water outlet temperature does not drop to the steady temperature for some reason despite the excessive input of the heat source steam, at the time when the timer counts the time limit time, the controller 6
Since 7 controls the steam flow control valve 72 to return from the second opening to the first opening, there is no inconvenience that the heat source steam is unnecessarily long-charged.

Further, the absorption refrigerator having the above-mentioned structure, which is used by switching the operation mode according to the magnitude of the load as described above, has its evaporator / absorber system divided into two systems and has a refrigerating capacity of 5000 RT. The capacity is increased so that Therefore, as compared with the case where the evaporator and the absorber each having a single unit are upsized to improve the refrigerating capacity to 5000RT, the evaporators 11 and 4 of both evaporator / absorber systems 1 and 2 are compared.
1 and the absorbers 12 and 42 can be downsized, and accordingly, the first and second evaporator / absorber systems 1 and 2 can be downsized.

Therefore, the installation space for the entire refrigerator can be made smaller than in the case where the evaporator and the absorber each having a single unit are upsized to improve the capacity. By the way, the installation area of the absorption refrigerator according to the present embodiment having a refrigerating capacity of 5000RT is 74.1 m ² , which is about 25 times that of the conventional refrigerator.
% Space saving.

Furthermore, as described above, the first and second evaporators
Since the absorber systems 1 and 2 can be made smaller than the case where a single-unit evaporator and an absorber are respectively increased in size to improve the capacity, these evaporator / absorber systems 1, 2 are
As well as making it easier, it can be easily transported and delivered to the installation site.

[0062]

The present invention is carried out in the form as described above, and has the following effects.

A method of operating an absorption chiller having a plurality of evaporator / absorber systems, in which a part of the plurality of evaporator / absorber systems is used and another system is used under a predetermined load or less. According to the method of the invention, the system is operated in a stopped state, and in the load range larger than the predetermined load, the part of the system and the system of at least a part of the stopped system are used together. It is possible to secure a large flow rate of the lithium bromide solution flowing to some evaporator / absorber systems operated in the low load range. Thereby, in particular, the absorber tube of the used absorber is prevented from drying,
Since it is possible to suppress the deterioration of the absorption performance of the absorber, it is possible to improve the efficiency of the entire refrigerator in the low load region. Further, in the method of the present invention, the amount of heat source to be given to the regenerator is excessively added to the rated heat source consumption amount or more by switching the operation mode, and the concentration of the lithium bromide solution in the absorption refrigerator is increased to lower the refrigerating capacity. Since the above is prevented, it is possible to suppress an excessive driving disturbance due to the switching of the driving mode.

The absorption refrigerator of the present invention comprises an evaporator, an absorber, a regenerator, and a condenser, uses water as a refrigerant, uses a lithium bromide solution as an absorbent, and uses heat as a driving source. In the absorption chiller, the evaporator, the refrigerant pump for supplying the refrigerant to the refrigerant nozzle of the evaporator, the absorber, and the low-concentration lithium bromide solution in the absorber are supplied to the regenerator side. With a plurality of evaporator / absorber system having a solution pump to be used, under a predetermined load or less, a part of the plurality of the evaporator / absorber system is used and the other system is stopped and operated, and In a load range that is larger than the predetermined load, a switching valve that operates by using both the partial system and at least a part of the system that has been stopped is provided, so that the system is operated in the low load range. Some evaporators The flow rate of the lithium bromide solution flowing through the absorber system number can be secured. As a result, in particular, it is possible to prevent the absorber tube of the used absorber from drying and suppress the deterioration of the absorption performance of the absorber, so that the efficiency of the entire refrigerator in the low load region can be improved. Further, in the absorption chiller of the present invention, the amount of the heat source supplied to the regenerator via the heat source amount control valve is excessively supplied to the regenerator in excess of the rated heat source consumption amount as the operation mode is switched by the control of the controller. Then, since the concentration of the lithium bromide solution in the absorption refrigerator is increased to prevent the refrigerating capacity from being lowered, it is possible to suppress the excessive disturbance of the operation due to the switching of the operation mode. Moreover, the absorption refrigerating machine of the present invention is provided with a plurality of evaporators / absorber systems, and each of the evaporators and absorbers having a single-unit configuration has a capacity equal to or greater than that of improving the capacity by a plurality of evaporators / absorbers. Since it can be obtained with an absorber system,
As the absorber system can be made smaller, the installation space of the refrigerator as a whole can be made smaller compared to the case where the evaporator and the absorber of single-unit configuration are respectively increased in size to improve the capacity. Since the evaporator / absorber system can be made compact, the evaporator / absorber system can be manufactured easily, and the transportation / delivery to the installation site becomes easy.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an absorption refrigerator according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a steam consumption rate and a load in the absorption refrigerator shown in FIG.

FIG. 3 is a characteristic diagram showing a relationship between a steam consumption rate and a load in a conventional absorption refrigerator.

[Explanation of symbols]

1, 2 ... Evaporator / absorber system 3 ... condenser 4 ... Low temperature heat exchanger 5 ... High temperature heat exchanger 6 ... High-pressure regenerator 7 ... Low pressure regenerator 11, 41 ... Evaporator 12, 42 ... Absorber 13, 43 ... Refrigerant pump 14, 44 ... Solution pump 16, 46 ... Cold water inlet line (cold water distribution pipe) 17, 47 ... Cold water outlet line (cold water distribution pipe) 18, 48 ... Chilled water pump 19, 49 ... Control valve (switching valve) 20, 50 ... Refrigerant nozzle 22, 52 ... Operation valve (switching valve) 29, 59 ... Solution nozzle 30, 60 ... Concentrated solution pump 31, 61 ... Operation valve (switching valve) 32, 62 ... Solution line 33, 63 ... Operation valve (switching valve) 64 ... Operating valve (switching valve) 66 ... Cold water temperature sensor 67 ... Controller 70 ... Input line (heat source input line) 72 ... Steam flow control valve

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuaki Yamauchi Inventor No. 1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Plant (72) Inventor Nakazato, Niihama, Niihama, Arai-cho, Takasago-shi, Hyogo No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Plant (56) Reference JP-A-3-233266 (JP, A) JP-A-4-139360 (JP, A) JP-A-9-14785 (JP, A) JP-A 6-213527 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 15/00 303 F25B 15/00 306

Claims (2)

(57) [Claims] 1. An evaporator having a refrigerant nozzle for spraying a refrigerant, a refrigerant pump for supplying a refrigerant to the nozzle, and a solution nozzle for spraying a concentrated lithium bromide solution to the refrigerant vapor generated in the evaporator. A method for operating an absorption refrigerator having a plurality of evaporators / absorber systems each having a solution pump for supplying a low-concentration lithium bromide solution in the absorber to the regenerator side, and a predetermined load. In the following, a part of the plurality of evaporator / absorber systems is used, and the other system is stopped and operated, and in a load range larger than the predetermined load, the part of the system and the stop The system is operated by using at least a part of the system, and the heat source amount supplied to the regenerator when the operation mode is switched is temporarily changed to the rated heat source in the regenerator. Excessive consumption or more The method of operating the absorption refrigerating unit, characterized by. 2. An evaporator for evaporating and evaporating the refrigerant into a refrigerant vapor by spraying the refrigerant from the refrigerant nozzle on an evaporator tube having a refrigerant nozzle through which cold water flows,
An absorber having a solution nozzle that absorbs the refrigerant vapor generated in the evaporator into a concentrated lithium bromide solution sprayed from the solution nozzle; and lithium bromide that has become a low concentration by absorbing the refrigerant vapor. A regenerator that heats the solution to evaporate the refrigerant in this solution to supply a concentrated lithium bromide solution to the absorber, and a refrigerant condensed and liquefied by condensing the refrigerant vapor generated in the regenerator. In the absorption refrigerator having a condenser for supplying the evaporator to the evaporator, a low-concentration lithium bromide solution in the evaporator, the refrigerant pump for supplying the refrigerant to the refrigerant nozzle, the absorber, and the absorber. And a plurality of evaporator / absorber systems having a solution pump for supplying the regenerator side to the regenerator side, and under a predetermined load, a part of the plurality of evaporator / absorber systems is used and other systems are suspended. Driving And in a load range larger than the predetermined load, a switching valve that operates by using both the partial system and at least a partial system of the stopped system, and the evaporator / absorber A cold water temperature sensor that detects the outlet temperature of the cold water sent from the system to the cooling load, and the operation mode is switched by opening and closing the switching valve based on the outlet temperature detected by this sensor, and the regeneration is accompanied by this switching. An absorption refrigerating machine, comprising: a controller for temporarily supplying an excessive amount of heat source to be supplied to the regenerator to a rated heat source consumption amount or more in the regenerator.