JP3434283B2 - Absorption refrigerator and how to start it - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerating machine, and more particularly to an absorption refrigerating machine having a starting bypass valve for lowering the cold water temperature at the time of starting and a starting method thereof.

[0002]

2. Description of the Related Art An absorption chiller is a chiller that uses water as a refrigerant and lithium bromide solution as an absorbent and heat as a driving source.
This is a refrigerator that is effective in utilizing waste heat. This absorption refrigerator is composed of an evaporator, an absorber, a regenerator, and a condenser as main equipment, and each of the evaporator and the absorber is equipped with a single unit, and these are matched to the refrigerating capacity of the absorption refrigerator. It is formed in size.

Then, the steam produced by the steam generator is fed to the regenerator of the absorption refrigerator using, for example, steam as a drive source. Since a boiler for district cooling and heating is used as the steam generator, a part of the steam generated by this steam generator is fed to the regenerator. This type of absorption refrigerator detects the outlet temperature of the cold water supplied from the evaporator to the cooling load,
When the detected temperature is higher than the set value, the outlet temperature of the cold water is lowered by increasing the amount of heat source vapor given to the regenerator to thicken the lithium bromide solution, and when the detected temperature is lower than the set value. Is configured to raise the outlet temperature of the cold water by reducing the amount of heat source vapor given to the regenerator and thinning the lithium bromide solution.

It is known that an absorption refrigerating machine is a machine which generally has a slow dynamic characteristic, and the starting time of the absorption refrigerating machine is such that it exhibits a predetermined refrigerating capacity, for example, about 90% of the rated refrigerating capacity. Since it usually takes 30 to 40 minutes, improvement thereof (for example, starting time of about 15 minutes) is required.

Therefore, the present inventor has paid attention to the above-mentioned conventional temperature control method, and excessively inputs the heat source steam into the regenerator at the time of start-up, thereby generating a large amount of heat in the internal cycle of the absorption refrigerator. We tried to shorten the start-up time of the absorption refrigerator.

However, in the conventional absorption refrigerator, the amount of heat source steam input to the regenerator is controlled only based on the outlet temperature of the cold water supplied from the evaporator to the cooling load, and the excess steam described above is used. Not configured to fit inputs. Therefore, it has been found that it is difficult to properly control the excessive injection of the heat source steam at the time of start-up, and the excessive injection of the heat source steam is likely to cause excess or deficiency and the following problems occur.

That is, when the excessive amount of the heat source steam is excessively supplied, the pressure of the district heating and cooling boiler drops too much, which causes a problem in supplying steam to the area and causes an abnormality of the lithium bromide solution in the regenerator. Boiling occurs, which causes a problem that causes carryover. On the contrary, when the excess amount of the heat source steam is insufficient, the above problem is improved, but since the concentration rate of the lithium bromide solution in the regenerator is reduced, it is possible to significantly shorten the startup time. I can't
I cannot satisfy the above request.

In an absorption refrigerator for district heating and cooling, for example, the temperature of the chilled water supplied to the district cooling and heating equipment as a load is higher than a predetermined temperature by, for example, 1 ° C. (for example, 7 ° C. or higher) for 30 minutes. There are cases where there are regulations regarding heat supply, such as not being allowed to flow. In order to cope with such usage conditions, an absorption refrigerating machine is known in which a cold water outlet line and a cold water inlet line for an evaporator are bypassed and a startup bypass valve is provided.

The start-up bypass valve is opened at the same time as the start-up of the start-up, and a part of the cold water which is heat-exchanged in the evaporator so as to lower the temperature and flows through the cold water outlet line is guided to the cold water inlet line to bypass the load. . As a result, as the inlet temperature of the absorption refrigerator is rapidly lowered, the chilled water outlet temperature can be made lower than or equal to the predetermined temperature. However, there is a regulation of the differential pressure between the cold water inlet side and the cold water outlet side, and if the operation of the start bypass valve is performed abruptly, the differential pressure becomes too large than the above regulation, so the operation of the start bypass valve should be delayed. However, it is difficult to control the operation of this valve to maintain the cold water outlet temperature at a predetermined temperature.

By the way, in the absorption refrigerator, if the temperature of the cold water is too low, the evaporator tube of the evaporator through which the cold water flows may be damaged due to freezing. Therefore, when the cold water outlet temperature becomes equal to or lower than a predetermined low water temperature (for example, 3.5 ° C.), the operation of the absorption refrigerator is stopped.

In the conventional absorption refrigerating machine having the above-mentioned start-up bypass valve, the temperature of the cold water flowing through the evaporator tube is sharply lowered at the time of start-up. In some cases, the refrigerating capacity of (1) increases rapidly at startup, and the cold water temperature falls below the predetermined low water temperature (referred to as cold water low temperature). When such a cold water low temperature state is reached, there is an inconvenience that the operation of the absorption chiller is stopped and the engine cannot be started (this is called a cold water trip). Therefore, when the heat source steam is excessively injected as described above in order to shorten the start-up time, the refrigerating capacity at the time of start-up increases more rapidly, and it is considered that the cold water trip is more likely to occur.

[0012]

The problem to be solved by the present invention is to obtain an absorption refrigerator that can be started while suppressing low temperature of cold water and a method of starting the same.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to an evaporator which has a refrigerant nozzle and sprays the refrigerant from the refrigerant nozzle on an evaporator tube through which cold water flows to evaporate the refrigerant to form a refrigerant vapor. An absorber having a solution nozzle that absorbs the refrigerant vapor generated in the evaporator into a concentrated lithium bromide solution sprayed from the solution nozzle; and a bromide that has a low concentration by absorbing the refrigerant vapor. A regenerator that heats the lithium solution to evaporate the refrigerant in the solution to supply a concentrated lithium bromide solution to the absorber,
A condenser that condenses and liquefies the refrigerant vapor generated in this regenerator to supply the condensed refrigerant to the evaporator, and a startup bypass valve provided across an inlet line and an outlet line of cold water for the evaporator. It is premised on the absorption chiller provided or its starting method.

In order to solve the above-mentioned problems, in the method for starting the absorption refrigerator according to the present invention, the starting bypass valve is opened and the starting of the starting bypass valve is started after the chilled water temperature drops to a predetermined temperature. And refrigerating capacity is reduced by controlling the refrigerant pump that supplies the refrigerant to the refrigerant nozzle, and after a predetermined time from this point, the refrigerant pump is driven so as to exert a predetermined capacity and is started. It is characterized by that.

In order to solve the above-mentioned problems, the absorption refrigerating machine of the present invention has a cold water temperature sensor for detecting the temperature of cold water passing through the cold water outlet line on the upstream side of the starting bypass valve, and at the start of starting. The startup bypass valve is opened, and after the startup, the cold water temperature sensor closes the startup bypass valve based on the detection of a cold water outlet temperature equal to or lower than a predetermined temperature, and heat of the refrigerant and the cold water in the evaporator. A controller that controls a refrigerant pump that supplies the refrigerant to the refrigerant nozzle so that replacement is not substantially performed, and that drives the pump so that the refrigerant pump exhibits a predetermined capacity after a predetermined time from this point. And is provided.

In the present invention, the evaporator, the refrigerant pump for supplying the refrigerant to the refrigerant nozzle of the evaporator, the absorber, and the solution for supplying the low-concentration lithium bromide solution in the absorber to the regenerator side are provided. The evaporator / absorber system having a pump can be applied to an absorption refrigerator having one system or a plurality of systems. Further, in the present invention, in order to temporarily reduce the refrigerating capacity at the time of start-up, the operation of the refrigerant pump is temporarily stopped, or the drive motor of the refrigerant pump is of an inverter drive type controlled by an inverter circuit. One is used, and the drive frequency applied to the drive motor is temporarily limited to, for example, half or less of that during steady operation, and the refrigerant pump is in an operating state, but the heat exchange between the refrigerant and the cold water in the evaporator does not occur. It can be carried out by means such as substantially not performing.

[0017]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic configuration diagram of an absorption refrigerator according to an embodiment. As shown in FIG. 1, the absorption refrigerator includes first and second evaporator / absorber systems 1 and 2 having the same refrigerating capacity, a regenerator, a condenser 3, a low temperature heat exchanger 4,
A high-temperature heat exchanger 5 is provided as a main device, water is used as a refrigerant, lithium bromide solution is used as an absorbent, and steam for district heating and cooling is used as a heat source. It is configured to exert its refrigerating capacity.

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

The first evaporator / absorber system 1 includes an evaporator 11
, Absorber 12, and inverter-driven refrigerant pump 13
And a solution pump 14. The evaporator 11 and the absorber 12 are configured in the same shell (high vacuum container). In the evaporator 11, an evaporator tube 15 (preferably using a multi-stage heat transfer tube group, for example, two stages) is arranged. A film evaporation promoting tube is preferably used for this tube 15. Cold water is supplied to the evaporator tube 15 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 to this line 17. After passing through the attached cold water pump 18, it flows out through the control valve 19 to the outside. The chilled water supplied to the chilled water inlet line 16 is used by the load 100 for district cooling and heating, and its temperature is raised to about 13 ° C. Cold water inlet line 16
(Or, the cold water outlet line 17 may be used.) An operation valve 22 that can open and close the flow path is attached.

A refrigerant nozzle 20 is arranged in the evaporator 11 so as to face the evaporator tube 15, and a refrigerant (water) drawn by a refrigerant pump 13 communicated with 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 container as described above, the refrigerant nozzle 20 is formed by the spray film evaporation method.
The refrigerant sprinkled from the evaporator tube 15 toward the evaporator tube 15 is 4
Boiling at about 6 ° C to 6 ° C and evaporating. Therefore, the temperature of the cold water flowing in the evaporator tube 15 decreases according to the latent heat of vaporization given to the refrigerant, and the cold water flows out, for example, as 6 ° C. cold water. This chilled water is sent to the cooling load for use, whereby the temperature rises to about 13 ° C. and the chilled water is introduced into the chilled water inlet line 16.

Inside the absorber 12 is an absorber tube 25.
(It is preferable to use a multi-stage, for example, two-stage heat transfer tube group.). A film evaporation promoting tube is also suitably used for this tube 25. About 32 which is guided to the absorber tube 25 by a cooling water inlet line (cooling water inlet pipe) 26
Cooling water at 0 ° C. is supplied through the control valve 27, and the cooling water flowing through the absorber tube 25 flows out to the outside through the cooling water outlet line (cooling water outlet pipe) 28. Cooling tower water or water from other water sources is used for cooling water,
The inlet temperature is, for example, about 32 ° C. A solution nozzle 29 is arranged in the absorber 12 so as to face the absorber tube 25, and a concentrated solution pump 30,
A concentrated solution of lithium bromide that is pumped by at least one of 60 is provided. This supply is provided by the concentrated solution pumps 30, 6
After passing through the low temperature heat exchanger 4 from 0 through the operation valves 31 and 61, it is led through the solution line (solution pipe) 32 through the operation valve 33 provided in this line 32.

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

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

The second evaporator / absorber system 2 has the same structure as the first evaporator / absorber system 1. That is, the evaporator 41, the absorber 42, the inverter-driven refrigerant pump 43, and the solution pump 44 are provided. The evaporator 41 and the absorber 42 are configured in the same shell (high vacuum container). Inside the evaporator 41, an evaporator tube 45 (multi-stage, for example, use of two stages of heat transfer tubes is preferable) is arranged. A film evaporation promoting tube is preferably used as the tube 45. Cold water is also supplied to the evaporator tube 45 through a cold water inlet line (cold water 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 flows out through the control valve 49. The cold water inlet line 46 is branched from the cold water inlet line 16 of the first evaporator / absorber system 1. Therefore, the cold water inlet line 46 is also supplied with the cold water whose temperature is raised to about 13 ° C. by being used by the load 100. The cold water inlet line 46 (or the cold water outlet line 47) may be provided with an operation valve 52 capable of opening and closing its flow path.

The cold water outlet lines 17 and 47 are joined. That is, the chilled water pumps 18 and 4 arranged in parallel with each other.
The discharge ports of 8 are merged after individually operating the operation valve 19 or 49. The merged cold water outlet line 65 on the downstream side of this junction is connected to the load 100. A chilled water temperature sensor 66 for detecting the temperature of chilled water passing through the outlet line 65 (outlet temperature) is attached to the outlet line 65.

On the downstream side of the cold water temperature sensor 66, the combined cold water outlet line 65 and the cold water inlet line 17 are
They are connected by a bypass flow passage 68 provided across them, and a start bypass valve 69 is attached in the middle of this flow passage 68. The start-up bypass valve 69 bypasses the load 100, is normally closed, and is opened / closed when the absorption refrigerator is started by using the motor as a power source. Note that reference numeral 65a in FIG. 1 denotes a check valve, which prevents cold water returning from the load 100 from flowing back through the starting bypass valve 69 to the cold water outlet lines 17, 47 side.

The information detected by the cold water temperature sensor 66 (the outlet temperature) is used by the controller 6 for controlling the entire absorption refrigerator.
7 is supplied. The controller 67 controls the opening and closing of the startup bypass valve 69 and the operation of the refrigerant pumps 13 and 43 as described later when the absorption refrigerator is started. Further, the controller 67 determines whether the load of the absorption chiller is operating at a predetermined load or less, or at a load larger than the predetermined load, based on the detection information of the cold water temperature sensor 66. It has a driving load determination means. Further, the controller 67 excessively inputs the heat source steam at the time of starting the absorption refrigerating machine to start the absorption refrigerating machine, and at the time of the rated operation after the starting, the amount of the heat source steam supplied to the regenerator of the absorption refrigerating machine based on the outlet temperature. It is supposed to be adjusted.

In FIG. 1, 70 is the first and second evaporators.
The temperature information for cold water low temperature detection is individually provided in the cold 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 judges that the cold water temperature has dropped too much and stops the operation of the absorption refrigerator. As a result, the first and second
Evaporator tube 15 for each evaporator / absorber system 1, 2
It is possible to prevent damage accidents caused by freezing of 45.

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

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

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

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

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

Reference numeral 96 in FIG. 1 denotes a boiler as a steam generator for district cooling and heating, and a steam header 96a is connected to a steam supply pipe 97 for district cooling and heating. Further, the steam header 96a is connected to a charging line (steam charging pipe) 98 for supplying steam to the high pressure regenerator 6 as a heat source thereof. The tip of the charging line 98 is connected to the heat transfer tube 71 included in the high pressure regenerator 6.

A steam flow rate control valve 72 for controlling the flow rate of the heat source steam passing through this line 99 is attached to the charging line 98, and is located, for example, upstream (or downstream side) of this valve 72. A steam flow sensor 99 for measuring the flow rate of the heat source steam through the charging line 98 is attached. The detection information of the steam flow sensor 99 is supplied to the controller 67. The steam flow rate control valve 72 has a first opening that allows the flow of the heat source steam commensurate with the rated steam consumption in the high pressure regenerator 6, and the high pressure regenerator 6 only when the absorption refrigerator is started.
And a second opening that allows the flow of a large amount of heat source steam that is excessively supplied in excess of the rated steam consumption, the opening is adjusted by using the motor as power. It should be noted that the first opening is not fixed, but includes opening adjustment for holding the chilled water temperature with respect to the cooling load at a set temperature (for example, 6 ° C.) constantly based on detection of the chilled water outlet temperature as described later. There is.

The controller 67 is preset with the maximum amount of heat source steam to be excessively charged into the high pressure regenerator when the absorption refrigerator is started. The controller 67 holds the steam flow rate control valve 72 at the second opening when the absorption refrigerator is started, and thereafter, after the stage where the steam flow rate detected by the steam flow rate sensor 99 reaches the maximum steam amount, The steam flow rate control valve 72 is kept at the first opening.

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

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

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

The low pressure regenerator 7 has its regenerator tube 76.
Has a solution nozzle 79 which is disposed to face the upper side of the low temperature heat exchanger 4 and the high temperature heat exchanger 5 and passes through a solution line (solution pipe) 80 drawn from between the low temperature heat exchanger 4 and the high temperature heat exchanger 5. The medium concentration solution of lithium bromide that has passed through the low temperature heat exchanger 4 is supplied. The solution nozzle 79 sprays the solution in lithium bromide onto the outer surface of the regenerator tube 76. for that reason,
The dispersed lithium bromide concentration solution is heated by the regenerator tube 76 in which the high-temperature refrigerant vapor generated in the high-pressure regenerator 6 is flowing. As a result, a part of the refrigerant contained in the medium-concentration solution evaporates to form a high-concentration lithium bromide concentrated solution, and the concentrated solution is stored at the bottom of the low pressure regenerator 7. The concentrated lithium bromide solution in the low pressure regenerator 7 passes through the solution confluence line 81 and the solution pump 3
It is sucked into 0 or 60 and supplied to the low temperature heat exchanger 4.

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

The automatic on-off valve 94 absorbs and refrigerates in the low load region below the predetermined load (for example, 50% load is preferable when the evaporator / absorber system has two systems as described above). When the machine is operated with one lung, it is used closed, and
When the absorption refrigerator is operated in both lungs in the load range H from the predetermined load to the rated point A, the absorption refrigerator is used open. In the single lung operation, the absorption refrigerator is operated by using one of the evaporator / absorber systems 1 and 2 and suspending the other. In the load range H extending from the predetermined load to the rated point A, the double lung operation is performed, and in the double lung operation, the absorption refrigerator is operated using both the evaporator / absorber systems 1 and 2.

Inside the condenser 3, a condenser tube 82 to which cooling water is supplied by the cooling water outlet line 28 is provided. The condenser 3 has an absolute pressure of 55 mmHg (about 1
/ 14 atm). In this condenser 3,
The refrigerant supplied through the refrigerant line 77 and the refrigerant vapor evaporated in the low pressure regenerator 7 and flowing into the condenser 3 are
It is cooled and condensed by heat exchange with the cooling water flowing through the condenser tube 82 to become a refrigerant (water). This refrigerant is sent to the refrigerant line (refrigerant piping) 83 by gravity and the pressure difference.

The refrigerant line 83 is 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 is connected to one evaporator 11, and the other refrigerant line 83b is provided with an operation valve 85 in the middle and is connected to the other evaporator 41. There is. Therefore, the refrigerant condensed and liquefied by the cooling water in the condenser 3 is supplied to at least one of the evaporators 11 and 41, and then is supplied to at least one of the evaporators 11 and 41, and then the refrigerant pump 13 or 43 supplies the refrigerant to the evaporator tubes 15 or 45 in the evaporators 11 and 41. Sprayed towards the outer surface.

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

When the absorption refrigerator having the above structure is started,
A part of the steam (heat source steam) introduced from the steam header 96a of the boiler 96 via the charging line 98 is excessively charged by a predetermined amount. That is, since the steam flow control valve 72 is held at the second opening, for example, fully opened by the controller 67, the steam input amount of the heat source steam to be supplied to the high pressure regenerator 6 through the charging line 98 per unit time is: A large amount of steam is oversupplied in the high pressure regenerator 6 in the rated operation of the absorption refrigerator, in excess of the rated steam consumption. About 1.1 times the rated steam consumption is preferable in the absorption refrigerator of the present embodiment. In addition, the degree of this excessive input changes the characteristics of the absorption refrigerator and the dynamic characteristics of the boiler 96 so that the steam supply capacity to the area of the boiler 96 is not significantly impaired and carryover does not occur in the absorption refrigerator. It is decided in consideration.

The excess input amount of the heat source steam input to the high pressure regenerator 6 is detected by the steam flow sensor 99 provided in the input line 98, and the detection information is supplied to the controller 67 one by one. And the high pressure regenerator 6
When the amount of heat source steam excessively injected into the controller reaches the maximum amount of steam preset in the controller 67, the opening of the steam flow rate control valve 72 is narrowed from the second opening after this point. The controller 67 controls so as to maintain the first opening. As a result, the heat source steam in an amount commensurate with the rated steam consumption in the high pressure regenerator 6 is fed into the high pressure regenerator 6, and the absorption refrigerator is shifted to the rated operation. The transition of the input of the heat source steam is shown by the dotted characteristic curve in FIG.

As described above, the steam flow rate sensor 99 is activated at the time of startup.
The controller 67 controls the opening degree of the steam flow rate control valve 72 so as not to exceed the maximum value of the heat source steam flow rate that is predetermined based on the detection information of 1. The amount is properly controlled, and the absorption chiller can be started while preventing excess and deficiency in excessive input of heat source steam.

Therefore, the excess amount of the heat source steam is exceeded,
Since the pressure of the district heating / cooling boiler 96 does not drop too much in response to this, it is possible to prevent a problem from occurring in the steam supply to the area via the steam supply pipe 97. further,
As described above, since the excess amount of the heat source vapor is not excessively supplied, the abnormal boiling of the lithium bromide solution in the high-pressure regenerator 6 is prevented from occurring, so that both evaporator / absorber systems 1, 2 It is possible to start the absorption refrigerator while preventing carryover from occurring.

As described above, by excessively adding the heat source vapor controlled so as not to exceed the upper limit of the heat source vapor flow rate, the concentration rate of the lithium bromide solution in the high pressure regenerator 6 at the time of start-up is increased, and the lithium bromide is increased. Since the concentration of the solution is optimized, the startup time from the start of startup to the transition to rated operation can be greatly shortened. By the way, in the configuration of this embodiment,
As shown in FIG. 3, it was confirmed by the demonstrative test that approximately 90% of the rated refrigerating capacity can be reached in about 15 minutes of starting time.

The absorption refrigerating machine having the above-mentioned structure is provided with a load 1
From 00, for example, it is restricted by the heat supply regulation that cold water of 7 ° C or more should not flow for 30 minutes or more, but it is possible to shorten the start-up time by appropriately adding the heat source steam as described above. Regardless, it is possible to prevent start-up failure due to cold water trip. This point will be described by taking as an example the case where the engine is started under the condition that the cold water temperature is 20 ° C.

At the same time when the activation is started, the activation bypass valve 69 is fully opened under the control of the controller 67.
As a result, a part of the cold water that has been cooled by at least one of the evaporators 11 and 41 toward the load 100 from the cold water outlet lines 17 and 47 through the combined cold water outlet line 65 passes through the start bypass valve 69 and the cold water inlet line. A short cycle is formed in which the suction cycle is guided to 16, 46 and returned to at least one of the evaporators 11, 41, so that the inlet temperature of the absorption refrigerator is rapidly lowered. Due to such a short cycle of cold water, the refrigerating capacity at startup of the absorption refrigerator is apparently increased. Therefore, the temperature of the cold water returned to at least one of the evaporators 11, 41 through the cold water inlet lines 16, 46 gradually decreases from 20 ° C., while the cold water outlet lines 17, 47 have a steeper gradient than the temperature decreasing gradient. And the temperature of the cold water passing through the combined cold water outlet line 65 also decreases.

The cold water temperature sensor 66 indicates that the temperature of the cold water passing through the cold water outlet lines 17 and 47 has reached a set temperature, for example, 11 ° C. lower than the cold water temperature of 13 ° C. used and returned by the load 100. At the time point detected by the above, the controller 67 executes the control for closing the startup bypass valve 68 and the control for stopping the operation of at least one of the refrigerant pumps 13 and 43. As a result, the refrigerant is not sprayed on at least one of the evaporator tubes 15 and 45, and the heat exchange between the refrigerant and the cold water is stopped. In other words, the refrigerating capacity is impaired. At the same time, the controller 67 operates its own timer.

As the refrigerating capacity is lowered in this manner, the outlet temperature of the absorption refrigerator and the inlet temperature are further lowered while relaxing the temperature lowering gradient, while being affected by the slow operation characteristic of the start bypass valve 68, Turn to rise. Therefore, it is possible to prevent the cold water outlet temperature from reaching a temperature range in which a cold water trip of 3, 5 ° C. or less occurs.

Further, the controller 67, at a time point when a predetermined time set in advance in the timer, for example, 1 second to 2 seconds has elapsed (at this time point, the startup bypass valve 69 is sufficiently closed). The control for restarting the operation of at least one of the refrigerant pumps 13 and 43 that has been stopped until then is executed. By this restart, the heat exchange between the refrigerant and the cold water in the evaporator is restored, so that the predetermined refrigerating capacity is again exhibited and the start of the absorption refrigerator is continued. Therefore, it is possible to perform the short-time start-up by excessively inputting the heat source steam as described above.

The changes in the cold water outlet temperature and the cold water inlet temperature at the time of startup described above are shown in FIG. That is, X in FIG. 4 indicates the change in the cold water inlet temperature, and Y in FIG. 4 indicates the change in the cold water outlet temperature. Therefore, the region shown by the diagonal lines between these curves indicates the change in the refrigerating capacity. Is shown. The curve Z shown by the dotted line in FIG. 4 shows the change in the cold water outlet temperature in the conventional absorption refrigerator in which the cold water low temperature described above is not avoided.

As described above, the absorption refrigerating machine having the above-described structure should not allow cold water of, for example, 7 ° C. or more on the load 100 side for district heating and cooling to flow for 30 minutes or more by opening the starting bypass valve 69 to start. Although it is possible to satisfy the heat supply regulation, the refrigerating capacity is temporarily reduced during the startup, so that the startup failure due to the cold water trip can be avoided. Then, by continuing such start-up, it is possible to shift to the steady operation in a short start-up time according to the start-up characteristic due to the excessive input of the heat source steam.

After the above startup, the amount of heat source vapor supplied to the high-pressure regenerator 6 is increased to increase the heating amount of the lithium bromide solution to increase the concentration of this solution, and the evaporator It is possible to lower the temperature of the cold water that exits 11, 41 and is supplied to the load. On the contrary, by reducing the amount of heat source vapor supplied to the high-pressure regenerator 6, the amount of heating of the lithium bromide solution is reduced and the concentration of this solution is reduced, so that the evaporator 11,
It is possible to raise the temperature of the cold water that exits 41 and is supplied to the load. Thereby, the cold water temperature with respect to the cooling load can be maintained at the set temperature (for example, 6 ° C.).

The control of the supply amount of the heat source steam to the regenerator is performed by the controller 67 using the first steam flow rate control valve 72.
It is realized by adjusting the opening, and this control is performed based on the detection of the cold water outlet temperature. In addition, the cold water outlet temperature, which is the basic data of the heat source steam supply amount control under the rated operation, is detected by the first and second evaporator / absorber systems 1 and 2 for both lung operation depending on the situation. In the absorption refrigerating machine configured to switch between the single-lung operation and the single-lung operation, the cold water temperature sensor 66 attached to the combined cold water outlet line 65 at which the cold water outlet lines 17 and 47 of both systems 1 and 2 are combined is responsible. The outlet temperature of the cold water that has been mixed and averaged in the cold water outlet line 65 is detected.

The absorption refrigerating machine of this embodiment having two evaporator / absorber systems is excellent in the following points. That is, when the outlet temperature of the cold water flowing through the combined cold water outlet line 65 detected by the cold water temperature sensor 66 is higher than the predetermined temperature, the controller 67 determines that the load of the absorption refrigerator is higher than the predetermined load (50%). , This controller 6
Based on the command in 7, the absorption refrigerator is operated in the dual lung operation mode.

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

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

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

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

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

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

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

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

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

Then, the shift from the double lung operation to the single lung operation,
Alternatively, the transition to the opposite is performed by the cold water temperature sensor 66 attached to the combined cold water outlet line 65 that joins the cold water supplied to the cooling load from both systems 1 and 2 as described above. The temperature of the cold water passing through is detected, and it is determined based on the detected temperature whether or not it is in the low load region. Therefore, it is possible to easily determine the predetermined load set as the reference for the operation switching, and to perform the double lung operation or the single lung operation depending on the load based on the determination.

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

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

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

Further, although the operation of the refrigerant pumps 13 and 43 is temporarily stopped in order to avoid the cold water trip in the above-mentioned one embodiment, instead of this, in the configuration of the above-mentioned one embodiment, an inverter control type refrigerant is used. The controller 67 controls the drive frequency applied to the pumps 13 and 14 by halving the drive frequency during steady-state operation, and the heat exchange between the refrigerant and the cold water in the evaporators 11 and 41 is substantially low. It is also possible to temporarily reduce the refrigerating capacity by not performing the above operation. In this embodiment, it is preferable that the evaporators 11 and 41 have a single-stage configuration instead of a multi-stage configuration.

[0076]

As described above, according to the start-up method of the present invention, after the start-up bypass valve provided between the inlet line and the outlet line of the cold water to the evaporator is opened to start the start-up, the cold water temperature is set. When the temperature drops to a predetermined temperature, the cooling bypass outlet is closed and the refrigerant pump that supplies the refrigerant to the refrigerant nozzle of the evaporator is controlled to temporarily reduce the refrigerating capacity, so the cold water outlet temperature causes a cold water trip. As the temperature is prevented from dropping too much, it is possible to start while suppressing the cold water low temperature.

Further, according to the absorption refrigerating machine of the present invention, after the start bypass valve provided between the inlet line and the outlet line of the cold water to the evaporator is opened to start the startup, the cold water outlet temperature is set to the predetermined temperature. Based on the cold water temperature sensor that detects that the temperature has dropped, and the detection information from this sensor, the startup bypass valve is closed and the refrigerant pump that supplies the refrigerant to the refrigerant nozzle of the evaporator is controlled to temporarily reduce the refrigeration capacity. Since the controller for controlling the cold water outlet is provided, it is possible to prevent the cold water outlet temperature from dropping too low to the temperature at which a cold water trip occurs. Therefore, it is possible to start while suppressing the cold water low temperature.

[Brief description of drawings]

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

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

FIG. 3 is a characteristic diagram showing the relationship between refrigerating capacity, heat source steam flow rate, chilled water outlet temperature, and time in the absorption refrigerator shown in FIG.

FIG. 4 is a characteristic diagram showing a relationship between a chilled water outlet temperature and a startup bypass valve and a refrigerant pump at the time of startup of the absorption refrigerator of FIG. 1.

[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 15, 45 ... Evaporator tube 16 ... Cold water inlet line 17 ... Cold water outlet line 20, 50 ... Refrigerant nozzle 29, 59 ... Solution nozzle 65 ... Combined cold water outlet line 66 ... Cold water temperature sensor 67 ... Controller 68 ... Bypass channel 69 ... Start-up bypass valve 72 ... Steam flow control valve 96 ... Boiler (steam generator) 96a ... Steam header 98 ... Input line 99 ... Steam flow sensor 100 ... load

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuaki Yamauchi Inventor No. 1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Plant (72) Inventor Nakazato, Niihama, Niihama, Arai-cho, Takasago-shi, Hyogo No. 1 Mitsubishi Heavy Industries, Ltd. Takasago Plant (56) Reference JP 2000-220906 (JP, A) JP 7-269979 (JP, A) JP 6-294558 (JP, A) JP 4 −139360 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 15/00 306

Claims (2)

(57) [Claims] 1. An evaporator for evaporating and evaporating the refrigerant into refrigerant vapor by spraying the refrigerant from the refrigerant nozzle onto an evaporator tube having a refrigerant nozzle and through which cold water flows,
An absorber having a solution nozzle that absorbs the refrigerant vapor generated in the evaporator into a concentrated lithium bromide solution sprayed from the solution nozzle; and lithium bromide that has become a low concentration by absorbing the refrigerant vapor. A regenerator that heats the solution to evaporate the refrigerant in this solution to supply a concentrated lithium bromide solution to the absorber, and a refrigerant condensed and liquefied by condensing the refrigerant vapor generated in the regenerator. Is a condenser for supplying to the evaporator, and a starting method of an absorption refrigerator comprising a starting bypass valve provided across an inlet line and an outlet line of cold water for the evaporator, wherein the starting bypass valve is After the cold water temperature has dropped to a predetermined temperature after opening and starting the startup, the cooling capacity is reduced by controlling the refrigerant pump that supplies the refrigerant to the refrigerant nozzle while closing the startup bypass valve, A method for starting an absorption refrigerating machine, characterized in that, after a predetermined time from this point, the refrigerant pump is driven and started so as to exhibit a predetermined capacity. 2. An evaporator for evaporating and evaporating the refrigerant into a refrigerant vapor by spraying the refrigerant from the refrigerant nozzle on an evaporator tube having a refrigerant nozzle through which cold water flows,
An absorber having a solution nozzle that absorbs the refrigerant vapor generated in the evaporator into a concentrated lithium bromide solution sprayed from the solution nozzle; and lithium bromide that has become a low concentration by absorbing the refrigerant vapor. A regenerator that heats the solution to evaporate the refrigerant in this solution to supply a concentrated lithium bromide solution to the absorber, and a refrigerant condensed and liquefied by condensing the refrigerant vapor generated in the regenerator. In the absorption refrigerating machine comprising a condenser for supplying to the evaporator, and a startup bypass valve provided across an inlet line and an outlet line of cold water for the evaporator, the cold water is provided upstream of the startup bypass valve. Cold water temperature sensor that detects the temperature of the cold water passing through the outlet line of the cold water, and the startup bypass valve is opened at the start of startup, and after this startup, the cold water temperature sensor detects the cold water outlet temperature below a predetermined temperature. Is detected based on the fact that the start bypass valve is closed, and a refrigerant pump that supplies the refrigerant to the refrigerant nozzle is controlled so that heat exchange between the refrigerant and cold water in the evaporator is not substantially performed. And a controller that drives the refrigerant pump so that the refrigerant pump exhibits a predetermined capacity after a predetermined time from this point of time.