JP3434284B2 - Absorption refrigerator - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[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]

The problem to be solved by the present invention is to improve the efficiency in a low load region and
It is to obtain an absorption refrigerating machine that is easy to manufacture, easy to transport and deliver, can be installed in a small space, and can be operated while keeping an appropriate amount of lithium bromide solution in the absorber.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to an evaporator which has a refrigerant nozzle and sprays the refrigerant from the refrigerant nozzle on an evaporator tube through which cold water flows to evaporate the refrigerant to form a 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 above problems, a refrigerant pump for supplying a refrigerant to the evaporator and the refrigerant nozzle,
A plurality of evaporator / absorber systems having the absorber and a solution pump for supplying a low-concentration lithium bromide solution in the absorber to the regenerator side; and a plurality of the evaporator / absorption under a predetermined load or less. A part of the power system 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 at least a part of the stopped system A switching valve that is operated using both the system and a solution level sensor that is provided in at least one absorber of the evaporator / absorber system and that detects the lower limit height of the lithium bromide solution in the absorber; A controller for limiting the solution delivery capacity of the solution pump connected to the absorber to which the solution level sensor is attached, based on the level sensor detecting the lower limit height. It is characterized by a door.

In order to solve the above-mentioned problems, 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 supplied to the regenerator side. A plurality of evaporator / absorber systems each having a solution pump for supplying the solution, and a switching valve provided in a solution line for individually introducing the lithium bromide solution supplied from the regenerator to each of the absorbers. Below the load, a part of the plurality of evaporator / absorber systems is used and the other system is stopped and operated, and in a load range greater than the predetermined load, the part of the system and the A switching valve for operating together with at least a part of the system which has been stopped, and an absorber of at least one of the evaporator / absorber system, which is provided with the lithium bromide solution in the absorber. Upper limit height A solution level sensor to output, based on the fact that the level sensor detects the upper limit height,
And a controller that controls the switching valve provided in the solution line so as to limit the amount of the solution passing through the solution line.

Further, in order to solve the above-mentioned problems, a low-concentration lithium bromide solution in the evaporator, the refrigerant pump for supplying a refrigerant to the refrigerant nozzle, the absorber, and the absorber is supplied to the regenerator side. A plurality of evaporator / absorber systems each having a solution pump for supplying the solution, and a switching valve provided in a solution line for individually introducing the lithium bromide solution supplied from the regenerator to each of the absorbers. Below the load, a part of the plurality of evaporator / absorber systems is used and the other system is stopped and operated, and in a load range greater than the predetermined load, the part of the system and the A switching valve for operating together with at least a part of the system which has been suspended, and a lithium bromide solution in the absorber provided in at least one absorber of the evaporator / absorber system. Upper limit of And a solution level sensor for detecting the lower limit height, and the switching provided on the solution line so as to limit the amount of the solution passing through the solution line based on the level sensor detecting the upper limit height. A controller for controlling the valve and limiting the solution delivery capacity of the solution pump connected to the absorber to which the solution level sensor is attached, based on the solution level sensor detecting the lower limit height; , May be provided.

In the present invention, the predetermined load can be arbitrarily set, and the evaporator / absorber system has two loads.
It can be implemented if there are more than one system. Further, in the present invention, as the switching valve (solution inlet valve) provided in the solution line for guiding the concentrated lithium bromide solution from each regenerator side to the absorber, a valve for opening / closing or changing the opening can be used. Further, in the present invention, the solution delivery capability of the solution pump for delivering the dilute lithium bromide solution from the absorber to the regenerator side can be limited by stopping the operation of the pump or reducing the operation speed. In the present invention, the solution level sensor includes a solution level sensor that detects only the lower limit height of the lithium bromide solution in the absorber, and a solution that detects only the upper limit height of the lithium bromide solution in the absorber. One or both of the level sensors can be used, or one that can detect both the lower limit height and the upper limit height can be used. Further, in the present invention, the refrigerating capacity of each evaporator / absorber system may not be the same, and it is preferable to apply the present invention to each evaporator / absorber system, but at least one system, For example, when the refrigerating capacity of a part of the system is larger than the other system, the present invention is applied to a system having a large refrigerating capacity by applying a configuration for appropriately maintaining the amount of lithium bromide solution in the absorber. It can also be implemented.

[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. For both pumps 13 and 14, inverter control type pumps that are operated by applying a drive frequency by an inverter circuit (not shown) according to the operating conditions of the absorption refrigerator are used. The controlled evaporator 11 and 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. The evaporator tube 15 has a cold water inlet line (cold water distribution pipe).
Cold water is supplied through the evaporator tube 16, flows through the evaporator tube 15, passes through a cold water outlet line (cold water distribution pipe) 17, passes through a cold water pump 18 attached to the line 17, and then passes through a control valve 19. It is leaked to the outside. The chilled water supplied to the chilled water inlet line 16 is used for the cooling device of the building (cooling load), and the usage thereof is about 1
The temperature has risen to 3 ° C. The cold water inlet line 16 (or the cold water outlet line 17 may be used) is provided 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 operation valve 33 is
It is used as a solution inlet valve for the concentrated lithium bromide solution supplied to the absorber 12 from the regenerator side.

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 inverter-controlled refrigerant pump 43, and the inverter-controlled solution pump 44 are provided. The evaporator 41 and the absorber 42 are configured in the same shell (high vacuum container). An evaporator tube 45 (preferably using a multi-stage heat transfer tube group) is arranged in the evaporator 31. 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. The cold water inlet line 46 is branched from the cold water inlet line 16 of the first evaporator / absorber system 1. Therefore, the cold water inlet line 46 is also supplied with the cold water whose temperature is raised to about 13 ° C. by being used for the 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 the outlet temperature of chilled water passing through the 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. The controller 67 determines, based on the information detected by the cold water temperature sensor 66, whether the load of the absorption refrigerator is operating at a predetermined load or less, or whether it is operating at a load greater than the predetermined load. Have means.

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. Operation valve 6
3 is used as a solution inlet valve for the concentrated lithium bromide solution supplied to the absorber 42 from the regenerator side.

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 supplied from this exchanger 4 to the high temperature heat exchanger 5.
Is supplied to. Concentrated solution pumps 30 and 6 arranged side by side
The discharge outlets of 0 are merged after individually passing through the operation valve 31 or 61 and are connected to the low temperature heat exchanger 4.

High-temperature steam is supplied to the heat transfer pipe 71 of the high-pressure regenerator 6 from a district heating / cooling facility (not shown) via a control valve 72. The heat transfer tube 71 is the high pressure regenerator 6
The dilute solution of lithium bromide supplied to the above is heated, and a part of the refrigerant is evaporated and vaporized from the dilute solution by the heating 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, and then 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 high temperature lithium bromide medium concentration solution returned from 3 was used to heat the lithium bromide dilute solution supplied from the low temperature heat exchanger 4 side, thereby increasing the concentration of the solution, while increasing the concentration of the solution. Heat recovery is performed to cool the concentrated solution. Then, the recovered lithium bromide medium-concentration solution merges with the high-concentration lithium bromide concentrated solution flowing out from the low-pressure regenerator 7, and the solution pump 30 or 60 causes the low-temperature heat exchanger 4 to flow.
And then cooled again, and then supplied to at least one of the absorbers 12 and 42 and 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.

Further, each of the absorbers 12 and 42 is provided with a solution level sensor 68 or 69 for detecting the height of the liquid surface of the dilute solution of lithium bromide accumulated therein. As the level sensors 68 and 69, an electrode rod type, a float type, an ultrasonic type or the like can be adopted. In the present embodiment, in particular, the longest common electrode rod and two sensor electrode rods that are shorter than the common electrode rod and have different heights from each other are provided, and the common electrode rod and the upper end portion of the sensor electrode rod are separated from each other via a dilute solution of lithium bromide. An electrode bar type level sensor is used to detect the upper and lower limits of the liquid level of the dilute solution of lithium bromide (solution level) depending on whether or not the two conduct. This sensor is preferable in that a reliable sealing property against a vacuum is guaranteed and stable measurement can be performed.

The longer one of the two sensor electrode rods having different heights indicates that the liquid level of the lithium bromide solution in the absorber 12 or 42 has reached a predetermined height (upper limit height) or more. The shorter electrode is the absorber 12 or 42 for detection.
The liquid level of the lithium bromide solution inside is a predetermined low (lower limit height)
It detects that the following has been reached. The upper limit height is set to prevent carryover, and the lower limit height is set to operate the solution pump 14 or 44 normally.

Level information (level information) of the liquid level of the lithium bromide solution in the absorbers 12 and 42 measured by the level sensors 68 and 69 is supplied to the controller 67, respectively. The controller 67 automatically closes the normally open operation valve 33 or 63 based on each level sensor 68 or 69 detecting the upper limit height.
Further, the controller 67 includes the level sensors 68 or 6
9 detects the lower limit height, the drive frequency applied to the operating solution pumps 14 and 44 is lowered to drastically reduce or substantially eliminate the solution delivery capability of these pumps 14 and 44. It is like this.

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.

That is, in this operation mode, the operation valves 22, 31, 33, 34, 52, 61, 63, 64, 8 are operated.
4, 85, the automatic open / close valve 94, and the like are all held in the open state, so that the pumps 13, 14, 18, 30,
43, 44, 48, 60, and condenser 3, regenerators 6, 7
Etc., the first and second evaporator / absorber systems 1,
2 are used together to repeat the above-described circulation of the refrigerant and the absorbent in the refrigerator. In this way all evaporators
In the double lung operation using the absorber systems 1 and 2, the characteristics formed by the curved line portion G1 in FIG. 2 and the curved line portion G3 that smoothly continues without forming an inflection point J at a load of 50%. It operates according to the curve and exhibits a maximum refrigeration capacity of 5000RT. In this case, the load is approximately 60 to 8
It can be operated most efficiently in the 0% range.

When the cold water outlet temperature 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.

That is, in this operation mode, the operation valves 22, 33, 34, 8 of the first evaporator / absorber system 1 are operated.
4, the control valves 19, 27, and the automatic opening / closing valve 94 are closed based on an instruction from the controller 67, and
Each pump 13, 14, 18, and 30 is stopped. On the other hand, each operation valve 5 related to the second evaporator / absorber system 2
2, 61, 63, 64, 85 and control valves 49, 57
Keeps the closed state, and each pump 4
3, 44, 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 its heat transfer surface can be effectively used, so that the absorption performance of the absorber 42 is prevented from being lowered and the low load region. 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, the 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-mentioned structure shifts from the double lung operation to the single lung operation in the low load region, whereby 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 outflow line 65 through the outflow 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, the inventor of the present invention has a sufficient capacity because the absorption refrigerator having the operation mode automatically switched according to the load as described above is provided with a plurality of evaporator / absorber systems. We have found that there is still room for improvement in order to bring out the benefits.

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 amount of the lithium bromide solution in the absorber included in the absorber system is likely to be different from the amount of the lithium bromide solution in the absorber included in the other evaporator / absorber system that is stopped in one lung operation.

Therefore, when the operation is switched from the one-lung operation to the both-lung operation, the amount of the dilute solution of lithium bromide in both absorbers 12 and 42 becomes unbalanced. As a result, in the evaporator / absorber system that has an absorber with an excessive amount of dilute lithium bromide solution, the dilute solution of lithium bromide is placed in the evaporator that is paired with the absorber. There is a possibility of causing a so-called carry-over phenomenon that overflows and flows. When this phenomenon occurs, the boiling point of the refrigerant in the evaporator rises, a state in which the amount of heat does not move even when there is a temperature difference (called refrigerant fouling) occurs, and the refrigerating capacity decreases. .
On the contrary, in the evaporator / absorber system equipped with the absorber in which the amount of the dilute solution of lithium bromide is too small, the solution pump connected to the absorber is normally operated. Since the required amount of the solution is insufficient, the solution pump causes cavitation, and the solution delivery capacity thereof is maintained in an extremely lowered state. Therefore, the solution flow rate characteristic in the refrigerator may be deteriorated, which may lead to problems such as an increase in pressure and concentration of the lithium bromide solution.

However, the absorption refrigerating machine of this embodiment detects the liquid level of the lithium bromide solution by the solution level sensors 68 and 69 individually attached to the absorbers 12 and 42 of the systems 1 and 2, respectively. , Operating valves 33 or 63 accordingly
Is automatically opened and closed, and the drive frequency for the solution pumps 14, 44 is changed to reduce the level difference of the liquid level of the lithium bromide solution in both absorbers 12, 42, thereby reducing the absorption levels of the absorbers 12, 42. The lithium bromide solution is stored in each of the above two types without excess or deficiency, and the operation can be performed.

That is, when the height of the liquid level of the lithium bromide solution in the absorber 12 or 42 becomes higher than the upper limit height, it is detected by the solution level sensor 68 or 69, and the controller according to the detection information. The control valve 67 closes the operation valve 33 or 63. This prevents the lithium bromide solution from accumulating excessively, so that it is possible to prevent refrigerant contamination due to carryover. In this case, the controller 67 always holds at least one operation valve in an open state to ensure solution circulation in the entire refrigerator.

On the contrary, when the liquid level of the lithium bromide solution in the absorber 12 or 42 becomes lower than the lower limit height,
Since it is detected by the solution level sensor 68 or 69, the steady drive frequency of 60 Hz applied to the solution pump 14 or 43 is lowered to, for example, 30 Hz by the control of the controller 67 according to the detection information. As a result, the amount of solution delivered from the solution pump 14 or 43 is greatly reduced or eliminated while the supply of the lithium bromide solution through the operation valve 33 or 63 is being continued. Therefore, after a certain time, the absorber 1
The amount of the lithium bromide solution in 2, 42 increases to such an extent that there is no fear of causing cavitation of the solution pump 14 or 43, and the driving frequency of steady 60 Hz for the solution pump 14 or 43 is detected by the level detection. Is applied.

As described above, as the amount of the lithium bromide solution in the absorbers 12 and 42 can be properly maintained,
The decrease in the solution flow rate characteristic in the refrigerator and the increase in the pressure and the concentration of the lithium bromide solution due to the decrease can be prevented, and the operation can be properly continued.

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 condenser having a single-unit configuration are respectively increased in size to improve the refrigerating capacity to 5000RT, the evaporators 11 and 4 of both evaporator / absorber systems 1 and 2 are
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 of the entire refrigerator can be reduced as compared with the case where the evaporator and the condenser 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 condenser are respectively increased in size to improve their capacities, these evaporator / absorber systems 1 and 2 can be made smaller.
As well as making it easier, it can be easily transported and delivered to the installation site.

[0062]

As described above, the present invention provides an evaporator,
In an absorption refrigerating machine equipped with an absorber, a regenerator, and a condenser, using water as a refrigerant, a lithium bromide solution as an absorbent, and heat as a driving source, the evaporator and the evaporator are included. Refrigerant pump that supplies the refrigerant to the refrigerant nozzle,
An evaporator having an absorber and a solution pump for supplying a low-concentration lithium bromide solution in the absorber to the regenerator side.
In addition to providing a plurality of absorber systems, when the load is below a predetermined load, some of the multiple evaporator / absorber systems are used and other systems are stopped and operated, and in a load range larger than the predetermined load. Since a switching valve for operating by using both the part of the system and at least part of the system that has been stopped is provided, part of the evaporator / absorber operated in the low load region. A large flow rate of the lithium bromide solution flowing through the system 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. Moreover, in the present invention, a plurality of evaporator / absorber systems are provided, and a plurality of evaporator / absorber systems have a capacity equal to or greater than that of increasing the capacity by increasing the size of a single-unit evaporator and condenser respectively. Since it is possible to obtain each evaporator / absorber system in a small size, it is possible to increase the capacity of the evaporator and the condenser with a single unit, and to improve the capacity of the entire refrigerator. The installation space is small. Further, according to the present invention, the individual evaporator / absorber system can be made smaller than in the case where the single-unit evaporator and the condenser are respectively increased in size to improve the capacity as described above. , The ease of making these evaporator / absorber systems has improved,
The transportation and delivery to the installation site will be easy.

Furthermore, in the invention constructed so that the solution delivery capacity of the solution pump is temporarily limited when the lithium bromide solution in at least one absorber is reduced to a height below the lower limit, the odor of the absorber is reduced. Since the amount of the lithium chloride solution is properly maintained, it is possible to provide an absorption refrigerator that can perform proper operation while avoiding a reduction in refrigerating capacity and a situation where the refrigerating capacity is inoperable.

Further, in the invention constructed so that the supply of the lithium bromide solution to the absorber is restricted when the lithium bromide solution in the at least one absorber has increased above the upper limit height, Since the amount of the lithium bromide solution is appropriately maintained, it is possible to provide an absorption refrigerating machine that can perform proper operation while avoiding refrigerant contamination due to carryover.

Furthermore, when the lithium bromide solution in at least one of the absorbers falls below the lower limit height, the solution delivery capacity of the solution pump is temporarily limited, and the lithium bromide solution in the absorber is temporarily reduced. In the invention configured so as to limit the supply of the lithium bromide solution to the absorber when increases above the upper limit height, the amount of lithium bromide solution in the absorber is properly maintained, so It is possible to provide an absorption refrigerating machine that can perform appropriate operation while avoiding a drop or a fall in an inoperable state and avoiding refrigerant contamination due to carryover.

[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) 67 ... Controller 68, 69 ... Solution level sensor

─────────────────────────────────────────────────── ─── 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-3-263561 (JP, A) JP-A-7-127945 (JP, A) JP-A 3-244972 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F25B 15/00 303 F25B 15/00 306

Claims (3)

(57) [Claims] 1. An evaporator for evaporating and evaporating the refrigerant into refrigerant vapor by spraying the refrigerant from the refrigerant nozzle onto an evaporator tube having a refrigerant nozzle and 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 at least one evaporator A solution level sensor provided in the absorber of the absorber system for detecting the lower limit height of the lithium bromide solution in the absorber, and the solution based on the level sensor detecting the lower limit height. An absorption refrigerating machine comprising: a controller that limits the solution delivery capacity of the solution pump connected to an absorber to which a level sensor is attached. 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. A plurality of evaporator / absorber systems for supplying the regenerator side with a solution pump, and a switching valve provided in a solution line for individually introducing the lithium bromide solution supplied from the regenerator to each of the absorbers. Including a predetermined load or less, a part of the plurality of evaporator / absorber systems are used and the other system is stopped and operated, and in a load range larger than the predetermined load, the part of the A switching valve that is operated by using both the system and at least a part of the system that has been stopped; and an odor inside the absorber that is provided in at least one absorber of the evaporator / absorber system. A solution level sensor for detecting the upper limit height of the lithium fluoride solution, and a solution level sensor provided on the solution line so as to limit the amount of the solution passing through the solution line based on the level sensor detecting the upper limit height. An absorption chiller, comprising: a controller that controls the switching valve that is present. 3. 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. A plurality of evaporator / absorber systems for supplying the regenerator side with a solution pump, and a switching valve provided in a solution line for individually introducing the lithium bromide solution supplied from the regenerator to each of the absorbers. Including a predetermined load or less, a part of the plurality of evaporator / absorber systems are used and the other system is stopped and operated, and in a load range larger than the predetermined load, the part of the A switching valve that is operated by using both the system and at least a part of the system that has been stopped, and the switching valve provided in the absorber of at least one of the evaporator / absorber system, A solution level sensor for detecting an upper limit height and a lower limit height of the lithium bromide solution, and based on the level sensor detecting the upper limit height, the solution so as to limit the amount of the solution passing through the solution line. The switching valve provided in the line is controlled, and based on the solution level sensor detecting the lower limit height, the solution level sensor is connected to an absorber to which the solution level sensor is attached. Absorption refrigerating machine characterized by comprising a controller for limiting the solution delivery capability of the solution pump.