JP2002349987A - Absorption refrigeration unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an absorption refrigeration unit, capable of improving efficiency in low-load region, high in manufacturability, facilitated in transportation, delivery or the like, capable of being installed while saving a space therefor and simple in the control of a heat source supplying amount. SOLUTION: The absorption refrigeration unit is equipped with evaporators, absorbers, regenerators 6, 7 and a condenser 3, while employing water as refrigerant, lithium bromide solution as the absorbing agent and heat as the drive source. Evaporator and absorber series 1, 2, having the evaporators 11, 41, refrigerant pumps 13, 43 for supplying the refrigerant to the refrigerant nozzles 20, 40 of both evaporators, the absorbers 12, 42 and solution pumps 14, 44 for supplying low-concentration lithium bromide solution in both absorbers to the side of regenerators, are provided. Single series operation, employing only one of the series of the series, and double serieses operation, employing both the serieses, are constituted so as to be switched. Two serieses of cold water, to be sent from evaporator tubes 15, 45 of both serieses into a cooling load, are merged, and the outlet temperature of the same is detected by a single cold water temperature sensor 66, while the flow rate of vapor for the regenerator 6 is controlled, based on the cold water temperature detected.

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 includes an evaporator, an absorber, a regenerator, and a condenser as main equipment, and the inside of the evaporator and the absorber is maintained at a high vacuum (6 to 7 mmHg in absolute pressure). A conventional absorption refrigerator has a single evaporator and a single absorber, each of which is formed in a size corresponding to the refrigerating 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 absorber is correspondingly increased. Must be improved. For that purpose, it is possible to cope by increasing the size of the evaporator and the absorber, but simply increasing the size of the evaporator and the absorber 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 absorber, the more difficult it is to manufacture, and the more difficult it is to carry out and deliver 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 which draws a downwardly convex arc in FIG. 3 through the rated point A, in a load region of approximately 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 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]

The problem to be solved by the present invention is to improve the efficiency in a low load range,
An object of the present invention is to provide an absorption refrigerator that is easy to manufacture, can be easily transported and delivered, can be installed in a small space, and has a simple control of a heat source supply amount.

[0008]

According to the present invention, there is provided an evaporator having a refrigerant nozzle, the refrigerant being sprayed from the refrigerant nozzle to an evaporator tube 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 a bromide having a low concentration by absorbing the refrigerant vapor. A regenerator for heating the lithium solution to evaporate the refrigerant in the solution and supplying the lithium bromide solution having an increased concentration to the absorber;
It is assumed that an absorption refrigerator includes a condenser that condenses refrigerant vapor generated by the regenerator and condenses and liquefies the refrigerant 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; and a plurality of the evaporators / absorbers at a predetermined load or less. While using a part of the power system and suspending the other system for operation, in a load range larger than the predetermined load, the system and the at least some of the suspended system A switching valve operated together, a chilled water temperature sensor for detecting an outlet temperature of chilled water to which a chilled water outlet pipe of each of the evaporator / absorber systems is merged and sent to a cooling load; And a controller that adjusts a heat source supply amount to the regenerator based on the outlet temperature detected by the controller.

In the present invention, the predetermined load can be arbitrarily determined, and the evaporator / absorber system has two loads.
It is preferable that the number of lines is equal to or more than the number of lines, and it is preferable that each line has the same refrigeration capacity.
In the present invention, the switching of the switching valve can be performed manually or automatically.

[0011]

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 having the same refrigeration capacity, a regenerator, a condenser 3, a low-temperature heat exchanger 4,
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 heating and cooling 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 with cold water through a cold water inlet line (cold water inflow pipe) 16, and the cold water flowing through the evaporator tube 15 passes through a cold water outlet line (cold water outflow pipe) 17 and is attached to this cold water pump 17 After passing through 18, the control valve 19
Is discharged to the outside through 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. Cold water inlet line 16 (or cold water outlet line 17
May be. ) Is provided with an operation valve 22 that can open and close the 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.

As a result, 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 28 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 12 is supplied to the absorber 12 by a solution pump 14 connected to the bottom through 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 heat 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 4
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 through a cold water inlet line (cold water inflow pipe) 46, and the cold water flowing through the evaporator tube 45 passes through a cold water outlet line (cold water outflow pipe) 47 to this line 47. After passing through the attached cold water pump 48, it is discharged to the outside through the control valve 49. Cold water inlet line 46
Is the cold water inlet line 16 of the first evaporator / absorber system 1
From the branch. Therefore, this cold water inlet line 4
Cold water whose temperature has been raised to about 13 ° C., which is used for cooling load, is also supplied to 6. The chilled water inlet line 46 (or the chilled water outlet line 47 may be provided) is provided with an operation valve 52 capable of opening and closing the flow path.

The cold water outlet lines 17 and 47 are joined. That is, the chilled water pumps 18, 4
The discharge ports 8 are joined after individually passing through the operation valves 19 or 49. An outflow line (cold water merging pipe) 65 downstream of the junction is connected to a cooling load. The outflow line 65 is provided with a chilled water temperature sensor 66 for detecting the temperature (outlet temperature) of chilled water passing therethrough. The information detected by the sensor 66 (the outlet temperature) 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 absorption chiller is operated at a load equal to or less than a predetermined load or is operated at a load larger than the predetermined load. It has a judging means. Further, the controller 67 appropriately adjusts the heat source amount (the steam amount in the present embodiment) given to the regenerator of the absorption refrigerator based on the outlet temperature.

In FIG. 1, reference numeral 70 denotes first and second evaporators.
The temperature sensor for detecting the low temperature of the chilled water provided separately in the chilled water outlet lines 17 and 47 of the absorber systems 1 and 2, and this detection information is also supplied to the controller 67. Controller 67
When the temperature sensor 70 detects a predetermined low temperature, for example, 3.5 ° C. or lower, it is determined that the temperature of the chilled water is too low, and the operation of the absorption refrigerator is stopped. Thereby, the first and second
Evaporator tube 15 for each evaporator / absorber system 1, 2
Forty-five freezing and puncture accidents can be prevented.

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 the load of approximately 40%, for example, a load of approximately 50% is set as a reference value for determining whether or not the load is a predetermined load. This approximately 50% load is automatically determined by the operating load determining means. In FIG. 2, E indicates a low load region of approximately 40% or less, and H 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 is raised to about 13 ° C. and returned to the cold water inlet lines 16 and 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 45. 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 28 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 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 the solution line 35, is supplied to the low-temperature heat exchanger 4 through this line 35, and is further supplied from the heat exchanger 4 to the high-temperature heat exchanger 5 Supplied to Concentrated solution pumps 30 arranged side by side,
The discharge ports 60 are joined after being individually passed through the operation valves 31 or 61 and connected to the low-temperature heat exchanger 4.

High-temperature steam is supplied to a heat transfer tube 71 of the high-pressure regenerator 6 from a district heating / cooling facility (not shown) via a heat source control valve 72. When the regenerator is provided with a gas burner, the heat source can be supplied to the regenerator 6 with the fuel gas supplied to the burner. The heat transfer tube 71 heats the lithium bromide dilute solution supplied to the high-pressure regenerator 6, and evaporates and evaporates a part of the refrigerant from the dilute solution to form a medium having a medium concentration of lithium bromide. Make a solution. The thus obtained solution in lithium bromide is supplied to the high-temperature heat exchanger 5 through the solution line (solution pipe) 73, and then supplied to the low-temperature heat exchanger 4 through the heat exchanger 5.

In the high-temperature heat exchanger 5, there is a solution line 7
The lithium bromide dilute solution supplied from the low-temperature heat exchanger 4 is heated by using the high-temperature lithium bromide concentration solution returned from 3 to increase the concentration of the solution. Heat recovery is performed to cool the solution. And
The heat-recovered lithium bromide-concentrated solution 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, where it is again supplied. After cooling, the absorber 12 or 42
And the solution nozzle 2 is supplied to at least one of
Sprayed from 9 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 is supplied to the low-pressure regenerator 7.
Is supplied to a regenerator tube 76 of the
6 through a refrigerant line 77 to be supplied to a refrigerant nozzle 78 disposed 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. Then, the solution in lithium bromide which has passed 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. for that reason,
The sprayed solution in lithium bromide 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 medium-concentration 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 concentrated solution of lithium bromide in the low-pressure regenerator 7 passes through the solution merging line 81 and passes through the solution pump 3.
It is sucked into 0 or 60 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 concentrated lithium bromide solution obtained by the low-pressure regenerator 6 is led). A first flow control valve 91 is provided in the solution line 90. The solution line 90 includes the first
A bypass flow path 92 that bypasses the flow control valve 91 is provided. 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 passages 92 thereto is equal to the number of the plurality of evaporator / absorber systems.
One or more bypass passages 92 are provided according to the number of evaporator / absorber systems. And in the bypass channel 92,
The second flow control valve 93 and the automatic opening / closing valve 94 are respectively mounted. 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 through the refrigerator is adjusted to be appropriate. 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 area below the predetermined load (for example, when the evaporator / absorber system has two systems as described above, the load is preferably 50%). 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.

A condenser tube 82 to which cooling water is supplied through the cooling water inlet line 26 is provided in the condenser 3. The condenser 3 has an absolute pressure of 55 mmHg (about 1 mmHg).
/ 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 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.

In the absorption chiller having the above structure, when the outlet temperature of the chilled water flowing through the outflow line 65 detected by the chilled water temperature sensor 66 is higher than a predetermined temperature, the load of the absorption chiller is higher than a predetermined load (50%). Is determined by the controller 67, and the absorption refrigerator is operated in the double lung operation mode based on the instruction 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 outlet temperature of the chilled water detected by the chilled 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, the absorption refrigerator uses only a part of the plurality of evaporator / absorber systems and suspends other evaporator / absorber systems based on the instruction from the controller 67. It is operated in the one-lung operation mode.

That is, in this operation mode, each of the operation valves 22, 33, 34, and 8 related to the first evaporator / absorber system 1 is used.
4. The control valves 19 and 27 and the automatic opening / closing valve 94 are closed based on an instruction from the controller 67,
Each pump 13, 14, 18, and 30 is stopped. On the other hand, each operating valve 5 related to the second evaporator / absorber system 2
2, 61, 63, 64, 85 and control valves 49, 57
Keeps the pump closed,
3, 44, 48, and 60 are kept running. Thereby, the first evaporator / absorber system 1 is stopped, and the one-lung operation using the second evaporator / absorber system 2 is executed.

In place 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. Accordingly, since the amount of the refrigerant returned to the evaporator 41 is kept constant, not only does the performance of the evaporator 41 not decrease, but also the absorber 4 paired with the evaporator 41.
The circulation amount 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. 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 absorber tube 55 of the absorber 42 is suppressed from drying out, and the heat transfer surface thereof can be used effectively, so that the absorption performance of the absorber 42 is prevented from lowering and the low load region is suppressed. It is possible to improve the efficiency of the refrigerator in a load region where a steam consumption rate exceeding the level C of the rated point A is required and the load region F in FIG.

In changing the operation mode,
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. Controller 6 to shift to single lung operation
It is desirable to adopt a configuration in which control is performed by the control unit 7. 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. That is, the combined flow rate of the lithium bromide medium-concentration solution having a medium concentration becomes smaller than that of the lithium bromide concentrated solution guided to the solution merging line 81, and the concentrated solution is sent to the absorber 42 by the concentrated solution pump 60 accordingly. The concentration of the lithium bromide solution 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 shifts 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 based on the outflow that merges the cold water supplied from both systems 1 and 2 to the cooling load as described above. The temperature of the chilled water passing through the outflow line 65 is detected by a chilled water temperature sensor 66 attached to the line 65, and whether or not the engine is in a low load region is determined 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 according to the load based on the predetermined load.

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 space required for installing the entire refrigerator can be reduced as compared with the case where the evaporator and the condenser having the single-unit configuration are each increased in size to improve the capacity. 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.

The absorption refrigerator has a high-pressure regenerator 6.
The amount of heat source supplied to the lithium bromide solution is increased by increasing the amount of high-temperature heat source vapor supplied through the heat source amount control valve 72 in this embodiment, thereby increasing the amount of heating of the lithium bromide solution to reduce the concentration of the solution. By making it thicker, the temperature of the cold water coming out of the evaporators 11 and 41 and supplied to the load can be lowered. Conversely,
By reducing the amount of heat source steam supplied to the high pressure regenerator 6,
The amount of heating of the lithium bromide solution can be reduced to lower the concentration of the solution and increase the temperature of the cold water coming out of the evaporators 11, 41 and being supplied to the load. Thereby, the chilled water temperature for the cooling load is set to the set temperature (for example, 6 ° C.).

The control of the supply amount of the heat source vapor to the regenerator as described above is realized by adjusting the opening of the heat source amount control valve 72 by the controller 67, and this control is performed based on the detection of the chilled water outlet temperature. I have.

In the absorption refrigerator having the first and second evaporator / absorber systems 1 and 2 and switching between the two-lung operation and the one-lung operation according to the situation, the two systems 1, 2 Of the cold water outlet lines 17 and 47 of
A chilled water temperature sensor 66 is attached to an outflow line 65 through which chilled water whose temperature is mixed and averaged is circulated toward a cooling load, and a chilled water outlet temperature which is basic data of the heat source steam supply amount control is detected. . Therefore, the piping configuration leading to the cooling load after merging can be simplified, and it is not necessary to provide a separate chilled water temperature sensor for both systems 1 and 2, and a single chilled water temperature sensor 66 can be used in common. The configuration is simple.

In addition, since the information of the chilled water outlet temperature detected in the case of both lung operation is single by this common use, the configuration of the controller 67 is simple and the heat source supply amount can be easily controlled. That is, when the cold water outflow lines 17 and 47 of both systems 1 and 2 which are substantially single units have independent configurations up to the end, different detections are made by the temperature sensors individually attached thereto. The heat source supply amount is controlled based on the cold water outlet temperature. Therefore, in the case of both lung operation, an arithmetic circuit for performing an arithmetic operation, such as averaging, for example, temperature information of the chilled water which is individually discharged from the two systems 1 and 2 and supplied to the load is required, and the configuration of the controller is complicated. Becomes However, in the absorption refrigerator having the above-described configuration, as described above, the chilled water separately discharged from the two systems 1 and 2 is mixed, and the temperature is averaged, and the temperature is detected by the chilled water temperature sensor. Therefore, the operation described above can be unnecessary in the controller 67.

[0055]

As described above, the present invention provides an evaporator,
An absorption refrigerator having 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, has an evaporator, which has an evaporator. Refrigerant pump that supplies 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;
A plurality of absorber systems are provided, and at a predetermined load or less, a part of the plurality of evaporator / absorber systems is used and other systems are stopped and operated, and in a load region larger than the predetermined load. , A switching valve that is operated by using both the partial system and at least a part of the suspended system is provided, so that the partial evaporator / absorber operated in a low load region is provided. A large flow rate of the lithium bromide solution flowing in the system can be secured. 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. Moreover, in the present invention, a plurality of evaporator / absorber systems are provided with a plurality of evaporator / absorber systems, and a plurality of evaporator / absorber systems have a capacity equal to or greater than that of improving the capacity by increasing the size of a single unit evaporator and a condenser. Therefore, as the individual evaporator / absorber systems can be made smaller, the entire refrigerator is compared with a case where the capacity of the evaporator and condenser in a single unit is increased by increasing their size. Installation space is small. Further, in the present invention, as described above, the individual evaporator / absorber systems can be made smaller in comparison with the case where the capacity of the evaporator and the condenser having a single unit configuration is increased by increasing the size thereof. , These evaporator / absorber systems are easier to build,
The transportation and delivery to the installation location are also facilitated. In addition, in the present invention, the chilled water sent from the plurality of evaporator / absorber systems to the load is combined, the outlet temperature of the combined chilled water is detected by the chilled water temperature sensor, and the heat source supply amount to the regenerator is controlled by the controller. , A single chilled water temperature sensor is required, and the controller does not need to calculate the detected chilled water outlet temperature, thereby simplifying the configuration of the controller. Can be provided.

[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 14, 44 ... Solution pump 15, 45 ... Evaporator tube 17, 47 ... Cold water outlet line (cold water outflow pipe) 18, 48 ... Cold water pump 19, 49 ... Control valve (switching valve) 20, 50 ... Refrigerant Nozzles 22, 52 ... Operating valves (switching valves) 29, 59 ... Solution nozzles 30, 60 ... Concentrated solution pumps 31, 61 ... Operating valves (switching valves) 33, 63, 64 ... Operating valves (switching valves) 65 ... Outflow lines (Cooled water merging pipe) 66 ... Cooled water temperature sensor 67 ... Controller 72 ... Heat source control valve 81 ... Solution merging line 83 ... Refrigerant line 84,85 ... Operation valve (switching valve)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Nobuaki Yamauchi 2-1-1, Araimachi, Arai-machi, Takasago-shi, Hyogo In-house Takasago Works, Mitsubishi Heavy Industries, Ltd. No.1 Mitsubishi Heavy Industries, Ltd. Takasago Mfg. F-term (reference) 3L093 AA01 BB18 MM07

Claims (1)

[Claims] 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. And a plurality of evaporator / absorber systems having a solution pump for supplying the evaporator / absorber system to the regenerator side. Driving In a load range greater than the predetermined load, a switching valve that operates using both the partial system and at least a partial system of the suspended system, and the evaporator / absorber system includes: A chilled water temperature sensor for detecting an outlet temperature of the chilled water to which the outlet pipes of the chilled water are merged and sent to the cooling load; and adjusting a heat source supply amount to the regenerator based on the outlet temperature detected by the sensors. An absorption refrigerator comprising: