JP3443100B2 - Absorption refrigerator and method of operating the same - 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 refrigerator, and more particularly to an absorption refrigerator suitable for forming a large-capacity machine.

[0002]

2. Description of the Related Art An absorption refrigerator is a refrigerator using water as a refrigerant, a lithium bromide solution as an absorbent, and heat as a driving source.
It is an effective refrigerator for utilizing waste heat. This absorption refrigerator has an evaporator, an absorber, a regenerator, and a condenser as main components, and the inside of the evaporator and the condenser is maintained at a high vacuum (6 to 7 mmHg in absolute pressure). In the conventional absorption refrigerator, a single evaporator and a single condenser are provided, each of which is formed in a size corresponding to the refrigeration capacity of the absorption refrigerator.

[0003] By the way, the refrigeration capacity of the conventional absorption chiller is 2500 RT at the maximum, but in order to increase the refrigeration capacity of this absorption chiller to, for example, 5000 RT, the capacity of the single-unit evaporator and the condenser is correspondingly increased. Must be improved. For that purpose, the size of the evaporator and the condenser can be increased. However, simply increasing the size of the evaporator and the size of the condenser requires a correspondingly large installation space.

[0004] However, since the installation space of the absorption refrigerator is often limited, it is considered that it is often inappropriate to install a large single unit as described above. In addition, the larger the evaporator and the condenser, the more difficult it is to make them, and the more difficult it is to carry and deliver them to the installation location.

FIG. 3 is a characteristic diagram showing the relationship between the steam consumption rate and the load of a conventional absorption refrigerator. In FIG. 3, reference symbol A denotes a rating point determined by the specifications of the absorption refrigerator. The load at A is approximately 100%. In addition, as can be seen from the characteristic curve B in which a downwardly convex arc in FIG. 2 is drawn through the rated point A, the steam consumption rate exceeds the level C at the rated point A in a load region of approximately 40% or less. ing. As can be understood from FIG. 3, the absorption refrigerator has a 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
In the 0% load region, the steam consumption rate is low and the operation can be performed most efficiently. However, when the load is in the low load region of about 40% or less, the steam consumption rate is required to exceed the steam consumption rate at the rated point A,
The efficiency of the entire refrigerator tends to decrease.

[0006] The absorption refrigerator is a refrigerator having better partial load characteristics than other refrigerators, such as the efficiency of operation in a partial load region exceeding the efficiency under rated conditions. Thus, the efficiency in the low load region is lower than the efficiency in the rated condition. The reason is that in the operation in the low load range, the flow rate of the lithium bromide solution flowing in the refrigerator is excessively reduced, and in particular, the flow rate of the lithium bromide solution in the single-unit absorber is excessively decreased. It is believed that the absorber tube has a drier condition 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, and 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 region as described above.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of operating an absorption refrigerator which can improve the efficiency in a low load range, and to improve the efficiency in a low load range. It is an object of the present invention to provide an absorption refrigerator that is easy to manufacture, easy to transport and deliver, and can be installed in a small space.

[0008]

A method of operating an absorption refrigerator according to the present invention comprises an evaporator having a refrigerant nozzle for spraying a refrigerant, a refrigerant pump for supplying a refrigerant to the nozzle, and an evaporator. An absorber with a solution nozzle for spraying a highly concentrated lithium bromide solution to the refrigerant vapor, a high-pressure regenerator and a low-pressure regenerator
Regenerator and a圧再production unit, and the low concentration method for operating the absorption refrigerating machine provided with a plurality of evaporators-absorber system the solution pump for supplying lithium bromide solution in the regenerator side having respective in this absorber In a predetermined load or less, a part of the plurality of evaporator / absorber systems is used and the other systems are stopped and operated, and in a load region larger than the predetermined load, the part is used. Operating together with at least some of the dormant systems ,
When operating below the specified load, the flow rate of the lithium bromide solution
Lithium bromide solution flowing out of the low pressure regenerator
Of the lithium bromide solution from the high pressure regenerator
The feature is to reduce the flow rate .

Further, the absorption refrigerator according to the present invention is characterized in that the refrigerant is sprayed from the refrigerant nozzle to an evaporator tube having a refrigerant nozzle and through which cold water flows, thereby evaporating the refrigerant to form a refrigerant vapor. An absorber having a solution nozzle and absorbing the refrigerant vapor generated in the evaporator into a lithium bromide solution having a high concentration sprayed from the solution nozzle, and absorbing the refrigerant vapor to have a low concentration. A regenerator that heats a lithium bromide solution to evaporate a refrigerant in the solution to supply the lithium bromide solution having a high concentration to the absorber, and condenses refrigerant vapor generated in the regenerator by condensing the refrigerant vapor. An absorption refrigerator including a condenser that supplies a liquefied refrigerant to the evaporator , wherein the evaporator, a refrigerant pump that supplies a refrigerant to the refrigerant nozzle, the absorber, and a low-concentration odor in the absorber. Conversion A plurality of evaporator / absorber systems having a solution pump for supplying a titanium solution to the regenerator side are provided, and at a predetermined load or less, a part of the plurality of evaporator / absorber systems is used and another system is used. In a load region larger than the predetermined load, a switching valve is provided that operates using both the partial system and at least a part of the suspended system . Previous
The regenerator includes a high-pressure regenerator and a low-pressure regenerator.
Lithium bromide solution passed through the heat exchanger from the solution outlet of the pressure regenerator
The solution was introduced, and the solution was concentrated at the concentration obtained in the low-pressure regenerator.
The first flow rate into the solution line that merges with the lithium bromide solution
A control valve is provided, and a bypass flow path bypassing the control valve is provided.
And one or more second flow control valves are connected to the bypass flow path.
And is closed below the predetermined load and is lower than the predetermined load.
It is characterized by providing an automatic open / close valve that opens in a large load range .

[0010] In the absorption refrigerator according to the present invention,
It is preferable that a chilled water temperature sensor for detecting the temperature of the chilled water passing through the chilled water pipe is attached to the chilled water circulation pipe, and whether the load is the predetermined load is determined based on the chilled water temperature detected by the sensor. In this case, the cold water temperature sensor may detect the inlet temperature or the outlet temperature of the cold water.

[0011]

In the absorption refrigerator and the method of operating the absorption refrigerator according to the present invention, the predetermined load can be arbitrarily determined, and the number of evaporator / absorber systems only needs to be two or more. In the refrigerator, the switching of the switching valve can be performed manually or automatically.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 includes first and second evaporator / absorber systems 1 and 2, a regenerator, a condenser 3, a low-temperature heat exchanger 4, and a high-temperature heat exchanger. 5 as main equipment, using water as a refrigerant, a lithium bromide solution as an absorbent, and steam for district cooling and heating as a heat source, and is a large capacity machine, for example, 5000RT.
It is configured so as to exhibit the refrigerating capacity.

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

The first evaporator / absorber system 1 includes an evaporator 11
, Absorber 12, refrigerant pump 13, solution pump 14
And The evaporator 11 and the absorber 12 are configured in the same shell (high vacuum vessel). Inside the evaporator 11, an evaporator tube 15 (preferably using a multi-stage heat transfer tube group) is arranged. As the tube 15, a film evaporation promoting tube is suitably used. Evaporator tube 15
Is supplied 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 a cold water pump 18 After that, it flows out through the control valve 19 to the outside. The chilled water supplied to the chilled water inlet line 16 is used for a cooling device of a building or the like (cooling load), and the temperature of the chilled water is raised to about 13 ° C. by using the cooling water. The chilled water inlet line 16 (or the chilled water outlet line 17 may be provided) is provided with an operation valve 22 that can open and close its flow path.

A refrigerant nozzle 20 is disposed in the evaporator 11 so as to face the evaporator tube 15, and a refrigerant (water) pumped by a refrigerant pump 13 connected to the bottom of the evaporator 11 via 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 vessel as described above, the refrigerant nozzle 20 is formed by the spray film evaporation method.
Refrigerant sprayed toward the evaporator tube 15 from the
It evaporates by boiling at about 6C to 6C. Therefore, the temperature of the cold water flowing in the evaporator tube 15 decreases in accordance with the amount of latent heat of evaporation given to the refrigerant, and flows out as, for example, 6 ° C. cold water. This chilled water is sent to a cooling load for use, whereby the temperature rises to about 13 ° C. and flows into the chilled water inlet line 16.

In the absorber 12, an absorber tube 25 is provided.
(The use of multiple stages of heat transfer tube groups is preferred.). As the tube 25, a film evaporation promoting tube is suitably used. Approximately 32 ° C. cooling water guided by a cooling water inlet line (cooling water inlet pipe) 26 is supplied to the absorber tube 25 through a control valve 27.
The cooling water flowing through the cooling water flows out through a cooling water outlet line (cooling water outlet pipe) 28 to the outside. As cooling water, cooling tower water or water from another water source is used, and its inlet temperature is, for example, approximately 32 ° C. A solution nozzle 29 is disposed in the absorber 12 so as to face the absorber tube 25, and the nozzle 29 is supplied with a lithium bromide concentrated solution pumped by at least one of the concentrated solution pumps 30 and 60. You. This supply is performed after passing through the low-temperature heat exchanger 4 from the concentrated solution pumps 30 and 60 through the operation valves 31 and 61, and then through a solution line (solution pipe) 32.
Is guided through the operation valve 33 provided in the first position.

Thus, the lithium bromide concentrated solution is sprayed toward the absorber tube 25. The lithium bromide concentrated solution thus sprayed absorbs the refrigerant vapor formed in the evaporator 11 and flowing into the absorber 12, and its concentration is diluted and collected at the bottom of the absorber 12. The heat of reaction accompanying the absorption is taken out by the cooling water flowing in the absorber tube 25. Therefore, the temperature of the cooling water discharged to the cooling water outlet line 26 by this heat exchange becomes, for example, about 40 ° C.

The diluted lithium bromide solution having a reduced concentration and collected at the bottom of the absorber 12 is supplied to the absorber 12 by a solution pump 14 connected to the bottom via an on-off valve.
It is pumped out and supplied to the low-temperature heat exchanger 4 via the solution line (solution pipe) 35, and further supplied from this exchanger 4 to the high-temperature heat exchanger 5. The dilute lithium bromide 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 configuration as the first evaporator / absorber system 1. That is, an evaporator 41, an absorber 42, a refrigerant pump 43, and a solution pump 44 are provided. The evaporator 41 and the absorber 42 are configured in the same shell (high vacuum vessel). Evaporator 3
An evaporator tube 45 (preferably a multi-stage heat transfer tube group is used) is disposed in 1. As the tube 45, a film evaporation promoting tube is suitably used. Cold water is also supplied to the evaporator tube 45 via a cold water inlet line (cold water circulation pipe) 46, and the cold water flowing through the evaporator tube 45 passes through a cold water outlet line (cold water circulation pipe) 47 and is attached to this line 47. After passing through the cold water pump 48, the control valve 4
9 to the outside. 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 has been raised to about 13 ° C., which is used for the cooling load. The chilled water inlet line 46 (or the chilled water outlet line 47 may be provided) has an operation valve 5 that can open and close its flow path.
2 are installed.

The discharge ports of the chilled water pumps 18 and 48 arranged side by side are joined individually after individually passing through the operation valves 19 or 49 and connected to a cooling load. A chilled water temperature sensor 66 that detects the outlet temperature of chilled water passing through the line (flow pipe) 65 downstream of the junction is attached. The detection information of the sensor 66 is supplied to a controller 67 that controls the entire absorption refrigerator. The controller 67 determines, based on the detection information of the chilled water temperature sensor 66, whether the load of the absorption chiller is operated at a predetermined load or less or is operated at a load larger than the predetermined load. 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 FIG. 2, reference symbol A denotes a rated point determined by the specifications of the absorption refrigerator. The load at the rated point A is approximately 100%. or,
In the present embodiment, the upper limit of the low load range that is generally referred to, that is, a load slightly larger than a load of approximately 40%, for example, a load of approximately 50% is set as a reference value for determining whether or not a predetermined load. This approximately 50% load is automatically determined by the operating load determining means. In addition, in FIG. 2, E indicates a low load region of approximately 40% or less, and F indicates a load region from a load point of approximately 50% to a rated point A. Further, G in FIG. 2 shows a characteristic curve of the absorption refrigerator according to the present embodiment. The curve G has a curve portion G1 in a load region F and a low load at the load of approximately 50%. And a curved portion G2 in the region 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 continuing from the curved line G3 indicates characteristics when the absorption refrigerator of the present embodiment is operated in both lungs as described later. A curve section G2 shows a characteristic curve when the absorption refrigerator of the present embodiment is operated in one-lung operation in the low load range E side as described later.

In the evaporator 41, an evaporator tube 45 is provided.
The refrigerant nozzle 50 is disposed opposite to the evaporator 4.
Refrigerant (water) pumped by a refrigerant pump 43 connected to the bottom of 1 via an on-off valve flows through a refrigerant line (refrigerant pipe) 51 and is supplied to a 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 about 4 ° C. to 6 ° C. and evaporates. The temperature of the chilled water flowing through the inside decreases according to the latent heat of evaporation given to the refrigerant.
It is discharged as cold water. This cold water is sent to a cooling load and used for cooling, whereby the temperature rises to about 13 ° C. and flows into the cold water inlet line 46.

In the absorber 42, an absorber tube 55
(The use of multiple stages of heat transfer tube groups is preferred.). As the tube 55, a film evaporation promoting tube is suitably used. 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 cooling water flowing through the absorber tube 55 passes through the cooling water outlet line 28. Spilled out. A solution nozzle 59 is disposed in the absorber 42 so as to face the absorber tube 55, and the nozzle 59
A concentrated solution of lithium bromide pumped by at least one of the concentrated solution pumps 30, 60 is supplied. This supply passes through the low-temperature heat exchanger 4 from the concentrated solution pumps 30 and 60 through the operation valves 31 and 61, and then passes through a solution line (solution pipe) 62 branched from the solution line 32, It is guided through an operation valve 63 provided at 62.

Thus, the lithium bromide concentrated solution is sprayed toward the absorber tube 55 . The lithium bromide concentrated solution thus sprayed absorbs the refrigerant vapor formed in the evaporator 41 and flowing into the absorber 42, its concentration is diluted, and collected at the bottom of the absorber 42. The heat of reaction accompanying the absorption is taken out by the cooling water flowing through the absorber tube 55. Therefore, the temperature of the cooling water discharged to the cooling water outlet line 26 by this heat exchange becomes, for example, about 40 ° C.

The dilute lithium bromide solution having a reduced concentration and collected at the bottom of the absorber 42 is supplied to the absorber 42 by a solution pump 44 connected to the bottom via an on-off valve.
After being pumped out through an operation valve 64, it joins with the solution line 35, is supplied to the low-temperature heat exchanger 4 through this line 35, and is further supplied from the exchanger 4 to the high-temperature heat exchanger 5
Supplied to Concentrated solution pumps 30, 6 juxtaposed to each other
The discharge ports 0 are individually joined after passing through the operation valves 31 or 61 and connected to the low-temperature heat exchanger 4.

High-temperature steam is supplied to the heat transfer tube 71 of the high-pressure regenerator 6 from a district cooling / heating facility (not shown) through a control valve 72. The heat transfer tube 71 is a high-pressure regenerator 6
Is heated to evaporate and evaporate a part of the refrigerant from the dilute solution to produce a medium concentration lithium bromide solution. The thus obtained solution in lithium bromide is supplied to the high-temperature heat exchanger 5 through a solution line (solution pipe) 73, and then supplied to the low-temperature heat exchanger 4 through the exchanger 5.

In the high-temperature heat exchanger 5, the solution line 7
The high temperature solution in lithium bromide returned from 3 is used to heat the dilute solution of lithium bromide supplied from the low temperature heat exchanger 4 side, thereby increasing the concentration of the solution, while increasing the concentration of the solution in lithium bromide. The heat recovery is performed for cooling. Then, the heat-recovered solution in lithium bromide merges with the high-concentration lithium bromide concentrated solution flowing out of the low-pressure regenerator 7 and is supplied to the low-temperature heat exchanger 4 by the solution pump 30 or 60. After being cooled again, it is supplied to at least one of the absorbers 12 or 42 and is supplied to the solution nozzle 29 or 59.
Sprayed from.

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

The low-pressure regenerator 7 has a regenerator tube 76
And a solution nozzle 79 which is disposed above and opposed to the nozzle, through a solution line (solution pipe) 80 drawn out between the low-temperature heat exchanger 4 and the high-temperature heat exchanger 5. Thus, the solution in lithium bromide flowing through the low-temperature heat exchanger 4 is supplied. The solution nozzle 79 sprays the solution in lithium bromide on the outer surface of the regenerator tube 76. Therefore, the sprayed lithium bromide solution is heated by the regenerator tube 76 through which the high-temperature refrigerant vapor generated in the high-pressure regenerator 6 flows. As a result, a part of the refrigerant contained in the solution evaporates to form a high concentration lithium bromide concentrated solution, and this concentrated solution is stored at the bottom of the low-pressure regenerator 7. The lithium bromide concentrated solution in the low-pressure regenerator 7 is sucked into the solution pump 30 or 60 through the solution merging line 81 and supplied to the low-temperature heat exchanger 4 .

Further, the solution passes through the solution outlet 6a of the high-pressure regenerator 6, passes through the high-temperature heat exchanger 5, and joins the solution merging line 81 (the highly concentrated lithium bromide solution obtained in the low-pressure regenerator 6 is led). A first flow control valve 91 is provided in the solution line 90. The solution line 90 is provided with a bypass flow path 92 that bypasses the first flow control valve 91. It should be noted that the number of the solution lines 90 is one, and the number obtained by adding the number of the bypass flow paths 92 thereto is equal to the number of the plurality of evaporator / absorber systems. 1 depending on the number of evaporator / absorber systems
The above is provided. The bypass passage 92 has a second passage.
The flow control valve 93 and the automatic opening / closing valve 94 are respectively mounted. The degree of opening of the first and second control valves 91 and 93 is adjusted based on an instruction from the controller 67, and the flow rate of the refrigerant flowing through the refrigerator is adjusted by the adjustment. The opening / closing of the automatic opening / closing valve 94 is also executed based on an instruction from the controller 67.

The automatic on-off valve 94 has an absorption refrigeration at a low load region below the predetermined load (for example, a load of 50% is preferable when there are two evaporator / absorber systems as described above). When the aircraft is operated in one lung, it is closed and used,
When the absorption refrigerator is operated in both lungs in the load range H from the predetermined load to the rating point A, the absorption refrigerator is opened and used. In one-lung operation, one of the evaporator / absorber systems 1 and 2 is used and the other is stopped to operate the absorption refrigerator. In a load region H extending from the predetermined load to the rated point A, the two-lung operation is performed. In the two-lung operation, the absorption refrigerator is operated using both the evaporator-absorber systems 1 and 2.

The cooling water line 26 is provided in the condenser 3.
Is provided with a condenser tube 82 to which cooling water is supplied. The condenser 3 has an absolute pressure of 55 mmHg (about 1/1).
4 atm). In the 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 exchange heat with the cooling water flowing through the condenser tube 82. , And is cooled and condensed to become a refrigerant (water). This refrigerant is sent to the refrigerant line (refrigerant pipe) 83 by gravity and a pressure difference.

The refrigerant line 83 is provided in two systems or is branched into two systems as shown in FIG. One refrigerant line 83a is provided with an operation valve 84 in the middle and connected to one evaporator 11, and the other refrigerant line 83b is provided with an operation valve 85 in the middle and connected to the other evaporator 41. I have. 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 supplied to the evaporator tube 15 or 45 in the evaporators 11 and 41 by the refrigerant pump 13 or 43. Sprayed towards the outer surface.

In the absorption refrigerator having the above configuration,
Operation valves 22, 31, 33, 34, 52, 61, 63, 6
Reference numerals 4, 84 and 85 denote switching valves used for switching between single-lung operation and dual-lung operation by being opened and closed using a motor as a power source.
9 is also used as a switching valve for switching between single lung operation and dual lung operation. The automatic opening / closing valve 94 is also opened / closed using a motor as power. The absorption chiller can perform a heating operation, but since it is not relevant in the present invention, the description of the operation during the heating operation is omitted.

When the temperature of the chilled water flowing through the chilled water outlet line 47 detected by the chilled water temperature sensor 66 is higher than a predetermined temperature, the load of the absorption chiller is reduced from a predetermined load (50%). The controller 67 determines that the temperature is high, and the absorption refrigerator is operated in the two-lung operation mode based on a command from the controller 67.

That is, in this operation mode, each of the operation valves 22, 31, 33, 34, 52, 61, 63, 64, 8
4, 85, and the automatic open / close valve 94, etc., are all kept open, so that the pumps 13, 14, 18, 30,
43, 44, 48, 60; condenser 3, regenerators 6, 7
With the operation of the above, the first and second evaporator / absorber systems 1,
2 are used together, and the above-described circulation of the refrigerant and the absorbent into the refrigerator is repeated. In this way, all evaporators
In the two-pulmonary operation using the absorber systems 1 and 2, a characteristic is formed by a curved portion G1 in FIG. 2 and a curved 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 refrigerating capacity of up to 5000 RT. In this case, the load is approximately 60 to 8
Operation can be performed most efficiently in the 0% region.

When the temperature of the chilled water detected by the chilled water temperature sensor 66 is lower than the predetermined temperature, the controller 67 determines that the load of the absorption refrigerator is lower than the predetermined load (50%).
And based on the instruction 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 lung operation mode.

That is, in this operation mode, each of the operation valves 22, 33, 34, 6 related to the first evaporator / absorber system 1 is used.
4, 84, control valves 19 and 27, and automatic on-off valve 94
The pumps 13, 14, 18, and 30 are stopped while being closed based on an instruction from the controller 67. On the other hand, the respective operation valves 52, 61, 63, 64, 85 and the control valve 49 relating to the second evaporator / absorber system 2,
57 maintains the closed state, and the pumps 43, 44, 48, and 60 are maintained in the operating state. Thereby, the first evaporator / absorber system 1 is stopped, and the one-lung operation using the second evaporator / absorber system 2 is executed.

Instead of this, one-lung operation in which the first evaporator / absorber system 1 is used and the second evaporator / absorber system 2 is stopped based on a command from the controller 67 is performed. Can also. Also, the first and second evaporators
It is possible to switch between the single-lung operation and the double-lung operation even if the operation valves and the control valves for any of the absorber systems 1 and 2 are omitted. , The number of refrigeration units can be reduced, and the refrigerator configuration can be simplified and the cost can be reduced. However, in the configuration in which the operation modes are switched by providing the operation valves and the control valves in all of the evaporator / absorber systems as in the present embodiment, the first and second operations are 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 always used and does not deteriorate faster than the other systems. It is excellent in that it has high durability.

As described above, in the load region where the load is less than 50%, one-lung operation is performed.
The refrigerant flowing from the side 7 toward the first and second evaporator / absorber systems 1 and 2 is supplied only to the second evaporator / absorber system 2. Therefore, the amount of the refrigerant returned to the evaporator 41 is kept constant, and not only does the performance of the evaporator 41 not decrease, but also the circulation of the lithium bromide solution to the absorber 42 paired with the evaporator 41. The amount 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. The absorber tube group (absorber tube) has a load of 100
%, The circulation amount of the lithium bromide solution is designed to be optimal.
When the amount of circulating lithium bromide solution falls below the load, the operation is switched to one-lung operation, and the supply of the lithium bromide solution to one absorber 12 not used in this operation is stopped. Therefore, all of the lithium bromide solution circulating in the refrigerator flows into one tube group of the absorber 42 used in one-lung operation, so that the lithium bromide solution circulates through one tube group of the absorber 42. The amount can be doubled.

Therefore, the drying of the absorber tube 55 of the absorber 42 is suppressed, and the heat transfer surface of the absorber tube 55 can be effectively used. It is possible to improve the efficiency of the refrigerator in a load region requiring a steam consumption rate exceeding the level C of the rated point A, and a load region E of approximately 40% or less in FIG.

When changing the operation mode described above,
For example, when a load variation of 45% to 55% is applied, the transition from the double lung operation to the single lung operation or vice versa may be repeated, resulting in a lack of control stability. Therefore, in practice, for example, when the load increases to 50% or more, the two-lung operation is performed, and the two-lung operation is excessively maintained even when the load becomes 40% or less, and the load becomes 40% or less. It is preferable that the operation is shifted to the one-lung operation only when the condition is satisfied. With this configuration, chattering in control can be eliminated and stable control can be performed.

By the way, in the single-lung operation in the low load region, the heat transfer area of the evaporator / absorber system used in comparison with the two-lung operation is halved. As a result of the verification test, it was found that the amount of the lithium bromide solution flowing through the second evaporator / absorber system 2 used increased and the concentration thereof became deeper. However, the absorption chiller having the above-described configuration is configured such that the automatic opening / closing valve 94 of the bypass flow path 92 provided in communication with the solution outlet 6 a of the high-pressure regenerator 6 and bypassing the solution line 90 which joins the solution merging line 81 is one-sided. During the lung operation, the circulating flow characteristics in the refrigerator can be adjusted to a partial load (low load) by closing and closing the solution flow rate appropriately in the lung operation. In other words, the combined flow rate of the medium concentration lithium bromide solution with respect to the lithium bromide concentrated solution guided to the solution merging line 81 decreases, and accordingly, the concentrated solution pump 6
With 0, the concentration of the lithium bromide solution sent to the absorber 42 can be reduced. By controlling the concentration of the lithium bromide solution in accordance with the decrease in the circulation amount, the amount of the lithium bromide solution in the second evaporator / absorber system 2 used during one-lung operation is reduced. 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, in the absorption refrigerator having the above-described structure, in the low load range, the operation is shifted from the double-lung operation to the single-lung operation, 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 in the steam consumption rate at the time of the partial load is shown by a curved portion G2 in FIG.

As described above, the transition from the two-lung operation to the one-lung operation or vice versa is performed by the chilled water temperature sensor 66 attached to the chilled water outlet line 65 as described above. The temperature of the chilled water passing through is detected, and it is determined whether or not the load is in a low load range based on the detected temperature. It is possible to perform both-lung operation or single-lung operation as appropriate.

As described above, the absorption chiller of the above-described configuration used by switching the operation mode in accordance with the magnitude of the load has its evaporator / absorber system divided into two systems and has a refrigerating capacity of 5000 RT. This is a configuration in which the capacity is increased so that For this reason, the evaporators 11 and 4 of both the evaporator / absorber systems 1 and 2 are compared with the case where the single-unit evaporator and the condenser are each increased in size to increase the refrigerating capacity to 5000 RT.
1 and the absorbers 12 and 42 can be miniaturized, and accordingly, the first and second evaporator-absorber systems 1 and 2 can be miniaturized.

Therefore, the installation space of the entire refrigerator can be reduced as compared with a case where the capacity of the evaporator and the condenser of the single unit configuration is increased by increasing the size of each unit. Incidentally, the installation area of the absorption refrigerator having a refrigerating capacity of 5000 RT according to the present embodiment is 74.1 m ² , which is about 25 times that of the conventional refrigerator.
% Space saving.

Further, as described above, the first and second evaporators
Since the absorber systems 1 and 2 can be made smaller as compared with a case where the capacity of the evaporator and the condenser having a single unit configuration are respectively increased to improve the capacity, these evaporator / absorber systems 1, 2
And the transportation and delivery to the installation location can be facilitated.

[0052]

The present invention is embodied in the form described above and has the following effects.

An operation method of an absorption refrigerator having a plurality of evaporator / absorber systems, wherein a part of the plurality of evaporator / absorber systems is used while the other system is used at a predetermined load or less. According to the invention method in which the system is operated while stopped, and in a load region larger than the predetermined load, the system is operated using both the partial system and at least a part of the suspended system. In addition, a large flow rate of the lithium bromide solution flowing through some of the evaporator / absorber systems operated in the low load region can be secured. Thereby, in particular, to prevent the absorber tube of the used absorber from drying out,
Since the decrease in the absorption performance of the absorber can be suppressed, the efficiency of the entire refrigerator in a low load region can be improved. Moreover, this invention
Method, the lithium bromide solution is
Lithium bromide solution flowing out of low pressure regenerator
Of lithium bromide solution from high pressure regenerator merging with liquid
Since the volume is reduced, the circulating flow characteristics inside the refrigerator are reduced.
Can be combined.

In an absorption refrigerator having an evaporator, an absorber, a regenerator, and a condenser, using water as a refrigerant, a lithium bromide solution as an absorbent, and using heat as a driving source, an evaporator is used. Evaporator / absorber having a refrigerant pump for supplying a refrigerant to a refrigerant nozzle of the evaporator, an absorber, and a solution pump for supplying a low-concentration lithium bromide solution in the absorber to the regenerator. A plurality of systems are provided, and at a predetermined load or less, a part of the plurality of evaporator / absorber systems is used and the other systems are stopped and operated, and in a load region larger than the predetermined load, A switching valve provided with a switching valve that operates using both a part of the system and at least a part of the suspended system.
According to the description, it is possible to secure a large flow rate of the lithium bromide solution flowing in a part of the evaporator / absorber system operated in the low load region. Thereby, in particular, it is possible to prevent the absorber tube of the used absorber from drying out and to suppress a decrease in the absorption performance of the absorber, so that the efficiency of the entire refrigerator in a low load region can be improved. In addition, in the present invention, a plurality of evaporator / absorber systems are provided with a plurality of evaporator / absorber systems, and each of the plurality of evaporator / absorber systems has a capacity equal to or greater than that of improving the capacity by increasing the size of a single unit evaporator and a condenser. As the individual evaporator / absorber systems can be made smaller, the size of the evaporator and condenser in a single unit can be increased in size to improve the capacity. The entire installation space is small. Furthermore, since the individual evaporator / absorber systems can be made smaller as described above, as compared with the case where the capacity of the evaporator and the condenser of the single unit configuration are increased in size, respectively,・ The ease of making the absorber system is improved, and its transportation and delivery to the installation location are also facilitated. In addition, in the present invention,
Guides the lithium bromide solution coming out of the solution outlet of the pressure regenerator
Combined with the concentrated lithium bromide solution obtained with the low-pressure regenerator.
A first flow control valve is provided in the flowing solution line, and
A second flow control valve and a bypass flow path bypassing the valve;
It is closed when the load is below the specified load and is in the load range larger than the specified load.
Is equipped with an automatic open / close valve that opens,
Bromide flowing through the evaporator / absorber system during the operation of
At this time, despite the fact that the concentration of the
Lithium bromide for a rotating evaporator-absorber system.
Solution circulation is reduced by closing the automatic on-off valve
By, apply the solution circulation flow characteristics on the concentration balance of the refrigerator
Thus, the efficiency of the refrigerator in a low load region can be improved.

In the absorption chiller, the temperature of the chilled water passing through the circulation pipe is detected by a chilled water temperature sensor attached to the circulation pipe of the chilled water of the refrigerator. According to the invention that determines whether or not the predetermined load set as the reference for operation switching can be easily determined, the evaporator / absorber system is changed according to the load by switching the switching valve based on the predetermined load. Can drive .

[0056]

[Brief description of the 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 of 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 13, 44… Solution pump 16 ... Cold water inlet line (cold water distribution pipe) 17 ... Chilled water outlet line (cold water distribution pipe) 18, 48… Cold water pump 19, 49: control valve (switching valve) 20, 50 ... refrigerant nozzle 22, 52 ... Operating valve (switching valve) 29, 59: Solution nozzle 30, 60 ... concentrated solution pump 31, 61 ... operating valve (switching valve) 33, 63, 64 ... operating valve (switching valve) 65… Solution line 66… Cold water temperature sensor 67 ... Controller 81… Solution merging line 83 ... refrigerant line 84, 85 ... operating valve (switching valve) 90… Solution line 91: First flow control valve 92 ... Bypass channel 93 ... second flow control valve 94… Automatic on-off valve

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Fujiwara 2-1-1 Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-3-263561 (JP, A) Kaihei 4-139360 (JP, A) JP-A-8-121900 (JP, A) Shuichi Takada, Absorption Refrigerator, Japan, Japan Refrigeration Association, March 15, 1982, 200-202 (58) ) Field surveyed (Int. Cl. ⁷ , DB name) F25B 15/00 303 F25B 15/00 306

Claims (3)

(57) [Claims] 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 highly concentrated lithium bromide solution to refrigerant vapor generated in the evaporator are provided. Absorber, high pressure regenerator and low pressure
A regenerator comprising a regenerator and an absorption refrigerator comprising a plurality of evaporator-absorber systems each having a solution pump for supplying a low-concentration lithium bromide solution in the absorber to the regenerator side. At a predetermined load or less, a part of the plurality of evaporator / absorber systems is used and the other systems are stopped and operated. The system is operated by using both the system and at least a part of the system that has been stopped, and when the operation is performed at the predetermined load or less, the flow of the lithium bromide solution is reduced.
Lithium bromide solution flowing out of the low pressure regenerator
Of the lithium bromide solution from the high pressure regenerator
An operation method of an absorption refrigerator characterized by reducing a combined flow rate . 2. An evaporator having a refrigerant nozzle and spraying the refrigerant from the refrigerant nozzle to an evaporator tube through which cold water flows, thereby evaporating and evaporating the refrigerant to form refrigerant vapor;
An absorber having a solution nozzle and absorbing the refrigerant vapor generated in the evaporator into a lithium bromide solution having a high concentration sprayed from the solution nozzle; and lithium bromide absorbing the refrigerant vapor and having a low concentration. A regenerator that heats the solution to evaporate the refrigerant in the solution to evaporate the concentrated lithium bromide solution to the absorber, and a refrigerant condensed and liquefied by condensing refrigerant vapor generated in the regenerator. A condenser for supplying a refrigerant to the evaporator, the refrigerant nozzle, the absorber, and the low-concentration lithium bromide solution in the absorber. A plurality of evaporator / absorber systems having a solution pump for supplying the evaporator / absorber system to the regenerator side, and use a part of the plurality of evaporator / absorber systems and suspend other systems at a predetermined load or less. Luck Switching, and in a load range larger than the predetermined load, a switching valve is provided that operates using both the partial system and at least a partial system of the suspended system, and the regenerator Comprising a high-pressure regenerator and a low-pressure regenerator,
Lithium bromide passed through the heat exchanger from the solution outlet of the high-pressure regenerator
A solution was introduced and the solution was concentrated at the concentration obtained in the low pressure regenerator.
The first stream is added to the solution line that merges with the strong lithium bromide solution.
A flow control valve is provided and a bypass flow bypassing the control valve is provided.
One or more paths are connected, and the second flow rate is adjusted to this bypass flow path.
The valve is closed below the predetermined load and the valve is closed
An absorption chiller that has an automatic on-off valve that opens in larger load ranges . 3. A chilled water temperature sensor for detecting a temperature of the chilled water passing through the chilled water distribution pipe, and determining whether the load is the predetermined load based on the temperature of the chilled water detected by the sensor. The absorption refrigerator according to claim 2, wherein