JP3081472B2 - Control method of absorption refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an absorption refrigerator, and more particularly, to a method for controlling an absorption refrigerator which controls heating of a regenerator based on a concentration of a concentrated liquid.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. 58-160783 discloses that a condensing pressure is calculated from a refrigerant condensing temperature of a condenser or a condensing pressure is directly detected. Calculate the concentration, separately detect the outlet temperature of the low-temperature heat exchanger at which the temperature of the concentrated solution becomes the lowest, and take the difference between the concentration of the absorbing solution crystal at this temperature and the calculated concentration of the concentrated solution as a concentration margin, An absorption refrigerating machine control device is disclosed which performs control to increase the input of the heating source if the concentration allowance is large compared to the set value and decrease the input if the concentration margin is small, and performs crystallization prevention and high efficiency operation. ing.

[0003]

In the above prior art, the concentration of the concentrated liquid is calculated, and the concentration of the precipitated crystal is calculated from the temperature of the concentrated liquid at the outlet of the low-temperature heat exchanger according to the characteristic curve of the crystal precipitation. And
The difference between the crystal deposition concentration and the calculated concentration of the concentrated liquid is calculated as the concentration of the concentrated liquid. Furthermore, the set value of the concentration margin is set in the setting device, and when the calculated concentration margin becomes larger than the value set in the setting device, the heating amount is increased and the concentration margin is controlled to the set value. When the value becomes smaller, the heating amount is reduced, and the concentration margin is controlled so as to become a set value.

A setting value is also set by a setting device for the chilled water outlet temperature. When the chilled water outlet temperature is higher than the set value, the heating amount of the high-temperature regenerator is increased, and when the chilled water outlet temperature is lower, the heating amount is decreased, and the heating amount is reduced. Is controlled so that the chilled water outlet temperature becomes a set value. Then, the total of both the heating amount control based on the concentrated liquid concentration and the heating amount control based on the cold water outlet temperature is given to the heating source control valve as an actual heating source control amount.

[0005] As described above, two different controls are performed as the heating control, and contradictions occur in the control field. That is, when the chilled water outlet temperature has reached the set value, the concentration of the concentrated liquid increases, and when the concentrated liquid margin becomes smaller than the set value,
The heating amount is reduced, and control is performed so that the concentrated liquid margin becomes a set value. However, when the concentration becomes low, the refrigeration capacity becomes difficult to appear, so that the chilled water outlet temperature rises. Then, since the chilled water outlet temperature becomes higher than the set value, the heating amount is increased and the chilled water outlet temperature is controlled so as to become the set value. For this reason, the concentration of the concentrated solution also increases, the margin of the concentrated solution becomes smaller than the set value, and the danger of crystallization is not eliminated further.

Further, when the concentrated liquid margin reaches the set value, when the chilled water load decreases and the chilled water outlet temperature drops below the set value, the heating amount is reduced and the chilled water outlet temperature is reduced to the set value. Is controlled so that However, if the amount of heating is reduced, the concentration of the concentrated liquid becomes lower, and the margin of the concentrated liquid becomes larger than the set value. For this reason, the heating amount is increased, and control is performed such that the concentrated liquid margin becomes a set value. Then, the chilled water outlet temperature decreases due to the increase in the heating amount, and the chilled water outlet temperature control corresponding to the load cannot be performed.

As described above, the control for simultaneously adjusting both the chilled water outlet temperature and the concentrated liquid margin to the set value may not be established. In such a case, the control that satisfies one of the two is satisfied. That is, control with priority was required. An object of the present invention is to prevent generation of crystals and to extend the operating range of an absorption refrigerator.

[0008]

In order to solve the above-mentioned problems, the present invention is directed to a method of circulating a refrigerant and an absorbing liquid by connecting a regenerator, a condenser, an evaporator, an absorber and the like with piping. In a method of controlling an absorption refrigerator in which a passage is formed and a heating amount of a regenerator is controlled based on a cold water outlet temperature of an evaporator, the heating of the regenerator is performed once when the concentration of the concentrated liquid rises to a set value. After the first predetermined time has elapsed, heating of the regenerator is started, and when the heating of the regenerator is started, the heating amount of the regenerator is set to a heating amount smaller than the heating amount at the time when the concentration of the concentrated liquid reaches the set value. And a control method of the absorption refrigerator controlled for the second predetermined time.

Further, according to a second aspect of the present invention, a regenerator, a condenser, an evaporator, an absorber and the like are connected by piping to form a circulation path for the refrigerant and the absorbing liquid, and the amount of heating of the regenerator is reduced by the cooling water of the evaporator. In the control method of the absorption refrigerator controlled based on the outlet temperature, when the concentration of the concentrated liquid increases and reaches a set value, the heating of the regenerator is temporarily stopped, and thereafter, after the first predetermined time has elapsed, the regenerator is stopped. Heating is started, and at the start of heating of the regenerator, the heating amount of the regenerator is controlled for a second predetermined time by a heating amount obtained by multiplying the heating amount at the time when the concentration of the concentrated liquid reaches the set value by a value smaller than 1. An object of the present invention is to provide a method of controlling a refrigerator.

[0010] The invention according to claim 3 is a pipe connecting a regenerator, a condenser, an evaporator, an absorber and the like to form a circulation path for a refrigerant and an absorbing liquid, and connected to the regenerator to flow a heat source fluid. In the control method of the absorption refrigerator in which the opening degree of the control valve provided in the evaporator is controlled based on the chilled water outlet temperature, when the concentration of the concentrated liquid rises to the set value, the control valve is closed once, and then After the lapse of the first predetermined time, the control valve is opened to start heating the regenerator. At the start of heating of the regenerator, the opening of the control valve is set to an opening smaller than 1 when the concentration of the concentrated liquid reaches the set value. An object of the present invention is to provide a method of controlling an absorption refrigerator in which an opening degree multiplied by a value is controlled for a second predetermined time. .

Further, according to a fourth aspect of the present invention, when the second predetermined time has elapsed, the operation of the absorption refrigerator is stopped when the concentration of the concentrated liquid is higher than a set value. It provides a method. Further, the invention according to claim 5 is provided with a display, wherein when the second predetermined time has elapsed, when the concentration of the concentrated liquid is equal to or higher than a set value, the operation of the absorption refrigerator is stopped, and The method of controlling an absorption refrigerator according to any one of claims 1, 2 and 3 is provided.

Further, according to the present invention, when the second predetermined time has elapsed, if the concentration of the concentrated liquid is equal to or higher than the set value, the heating of the regenerator is performed after the second predetermined time has elapsed. A method for controlling an absorption chiller according to any one of claims 1, 2 and 3, wherein the control is stopped for a third predetermined time longer than the predetermined time. Further, in the invention according to claim 7, when the second predetermined time has elapsed, if the concentration of the concentrated liquid is equal to or higher than the set value, the heating of the regenerator is performed for the first predetermined time after the second predetermined time has elapsed. The third predetermined time is stopped for a longer time, and thereafter, every time the third predetermined time elapses, the concentration of the concentrated liquid is compared with the set value. The method according to any one of claims 1, 2 and 3, wherein the operation of the absorption refrigerator is stopped when the number of heating stops reaches a predetermined number. is there.

[0013]

According to the first, second and third aspects of the present invention, the heating of the high temperature regenerator 1 is stopped and the operation of the regenerator is stopped before the amount of heating of the high temperature regenerator 1 is reduced by increasing the concentration of the concentrated liquid. (1) Stop for a predetermined time, circulate the absorbing solution to dilute the concentrated solution, sharply reduce the concentration of the concentrated solution, and stop the operation of the regenerator and thereafter operate by reducing the heating amount of the regenerator. The set value of the concentration of the concentrated liquid at the time can be set close to the crystal precipitation concentration, and when the concentration of the concentrated liquid reaches the set value, the heating amount is reduced for a predetermined time without stopping the combustion when compared with the conventional control. The margin between the crystal deposition concentration and the set value can be reduced, the operating range based on the chilled water outlet temperature of the regenerator can be widened, and crystals of the absorbing liquid can be avoided.

According to the invention of claim 4, when the first predetermined time and the second predetermined time have elapsed, and when the concentration of the concentrated liquid is higher than the set value, the operation of the absorption refrigerator is stopped. In addition, concentration of the absorbing solution can be avoided, and crystallization of the concentrated solution due to a failure of a device provided in the absorbing solution circulating path of the absorption refrigerator can be reliably avoided. According to the fifth aspect of the present invention, when the second predetermined time has elapsed, when the concentration of the concentrated liquid is higher than the set value, the display is activated and the abnormality of the absorption chiller is notified to the administrator. In addition, the manager can quickly know the concentration abnormality of the absorption liquid and can inspect the absorption refrigerator in distinction from other abnormality or failure. As a result, the maintenance and inspection work can be simplified.

According to the sixth aspect of the present invention, when the concentration of the concentrated liquid is equal to or higher than the set value after the lapse of the second predetermined time, the heating of the regenerator is stopped by the first heating stop time which is the previous heating stop time. After stopping for a third predetermined time longer than the predetermined time and circulating the diluted liquid for a longer time, the concentration of the absorbing liquid, particularly the concentrated liquid, further decreases, and when the concentration of the concentrated liquid becomes lower than the set value, the absorption refrigeration is performed. It is possible to improve the stability of the operation of the absorption refrigerator while continuing the operation while avoiding the operation stop of the device.

Further, according to the invention of claim 7, the number of operation stoppages after the regenerator has stopped operating is counted, and the operation of the regenerator is only stopped until the counted number reaches the predetermined number. Continue circulation of liquid and refrigerant, supply chilled water to the load, and when the number of times reaches a predetermined number, stop the operation of the absorption chiller, continue operation of the absorption chiller as much as possible, and supply chilled water to the load. It is possible to avoid the generation of crystals of the absorption liquid in the absorption refrigerator while maintaining the above conditions.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. The figure shows a double-effect absorption refrigerator in which, for example, water (H2 O) is used as a refrigerant and a lithium bromide (LiBr) solution is used as an absorption liquid (solution).
In the figure, 1 is a high temperature regenerator provided with a gas burner 1B,
2 is a low-temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low-temperature heat exchanger, 7 is a high-temperature heat exchanger, and 8 to 12
Is an absorbent pipe, 15 is an absorbent pump, 16 to 18 are refrigerant pipes, 19 is a refrigerant pump, 20 is a gas pipe connected to the gas burner 1B, 21 is a heating amount control valve provided on the gas pipe 20, and 21A is Heating amount control valve 21 for gas pipe 20
An on-off valve such as a shut-off valve provided on a more upstream side;
2 is a cold water pipe, 23 is a cooling water pipe, and each is connected as shown in the figure.

Further, reference numeral 24 denotes a chilled water outlet temperature detector (hereinafter referred to as a first temperature sensor) provided on the evaporator chilled water outlet side of the chilled water pipe 22, and reference numeral 25 denotes a condenser temperature detector provided in the condenser 3 ( Reference numeral 26 denotes a regeneration temperature detector (hereinafter, referred to as a third temperature sensor) provided on the outlet side of the low-temperature regenerator 2. Further, reference numeral 27 denotes a control device of the absorption refrigerator, 30 denotes a concentration calculator for inputting temperature signals from the second and third temperature sensors 25 and 26 to calculate the concentration of the concentrated liquid, and 31 denotes a concentration calculator from the concentration calculator 30. And a capacity control device that operates based on the signal from the first temperature sensor 24. 32 is a first timer device, 33 is a second timer device, 34 is a display, and 35 is a buzzer. When the concentration of the concentrated liquid reaches the set value, the first timer device 32 closes the on-off valve 21A, stops the combustion of the gas burner 1B of the high-temperature regenerator 1, stops heating, and stops the high-temperature regenerator 1. A first predetermined time period for stopping the operation of the vehicle is set.
In addition, when the first predetermined time has elapsed, when the concentration of the concentrated liquid has reached the set value, the second timer device 33 sets the opening of the heating amount control valve 21 from the opening immediately before the stop of combustion. A second predetermined time for operating the high-temperature regenerator 1 while reducing the amount of combustion, that is, the amount of heating, is set.

During operation of the double effect absorption chiller constructed as described above, the control device 27 outputs an open signal to the on-off valve 21A, and the burner 1B is supplied with gas and burns. Then, the absorbent having a low concentration (hereinafter referred to as a diluted absorbent) is heated in the high-temperature regenerator 1, and the refrigerant is separated from the diluted absorbent and evaporated. The evaporated refrigerant flows through the low-temperature regenerator 2, exchanges heat with the absorbent in the low-temperature regenerator 2, lowers in temperature, and flows to the condenser 3. The condenser 3 from the high-temperature regenerator 1 through the low-temperature regenerator 2
The refrigerant vapor flowing to the condenser and the refrigerant vapor separated from the absorbing liquid in the low-temperature regenerator 2 evaporate and flow to the condenser 3 are both condensed and liquefied by exchanging heat with water flowing through the cooling water pipe 23. 1
7 flows to the evaporator 4 via. The refrigerant liquid exchanges heat with the cold water in the cold water pipe 22 to evaporate, and the cold water is cooled by the heat of vaporization and supplied to the load. Further, the refrigerant evaporated in the evaporator 4 flows to the absorber 5, and is absorbed by the sprayed thick absorbing liquid (hereinafter, referred to as a thick liquid).

The rare absorbing liquid that has absorbed the refrigerant in the absorber 5 is:
The temperature rises through the low-temperature heat exchanger 6 and the high-temperature heat exchanger 7 by the operation of the absorbent pump 15, and is sent to the high-temperature regenerator 1. The rare absorbent flowing into the high-temperature regenerator 1 is heated by the burner 1B, the refrigerant is separated and evaporated, and the medium of the medium concentration absorbs through the high-temperature heat exchanger 7 to lower the temperature and flows to the low-temperature regenerator 2. The absorption liquid is heated by the refrigerant vapor flowing from the high-temperature regenerator 1 in the low-temperature regenerator 2, and the refrigerant is further separated and evaporated. Then, the concentrated liquid having a higher concentration exchanges heat with the diluted absorbing liquid from the absorber 5 in the low-temperature heat exchanger 6, and its temperature is lowered and flows to the absorber 5 to be dispersed.

When the absorption chiller is operating as described above, the capacity control unit 31 inputs a signal of the chilled water outlet temperature from the first temperature sensor 24 and outputs a signal to the control valve 35 based on this signal. I do. Then, the heating amount of the high-temperature regenerator 1 is controlled by the cold water outlet temperature. Further, the concentration calculation device 30 inputs signals of the low temperature regenerator regeneration temperature T1 and the condensation temperature T2 from both the third temperature sensor 26 and the second temperature sensor 25. Then, the following first-order approximation formula is used in the concentration calculating device 30.

[0022]

(Equation 1)

The concentrated liquid concentration X is calculated based on the above. Here, in the above equation, a1, a2, a3 and a4 are constants. Then, the signal of the concentration of the concentrated liquid calculated by the concentration calculating device 30 is output to the capacity control device 31. The capacity controller 31 compares the concentration of the concentrated liquid with a preset value. For example, when the concentration of the concentrated liquid increases and reaches the set value, the capacity control device 31 operates. Then, the capacity control device 31 outputs a fully-closed signal to the heating amount control valve 21, and the heating of the absorbent in the high temperature regenerator 1, that is, the operation is stopped. Even after the high-temperature regenerator 1 stops operating, the control device 27 continuously outputs an operation signal to the absorbent pump 15, and the diluted absorbent circulates, so that the concentration of the absorbent gradually decreases. In addition, the capacity control device 3
The first timer device 32 starts counting at the same time as 1 outputs the fully closed signal.

Further, even if the operation of the high temperature regenerator 1 is stopped, the operation of the refrigerant pump 19 is continued, and the cold water cooled by the evaporator 4 is supplied to the load. When a first predetermined time, for example, 5 minutes, has elapsed after the operation of the high-temperature regenerator 1 has stopped, the timer device 3 counts up, resets the count, and outputs a signal. The capacity control device 31 that has input this signal outputs an open signal to the heating amount control valve 21, and the opening degree of the heating amount control valve 21 is a value obtained by multiplying the opening degree immediately before the previous full closing by a number less than 1 (for example, 60%).
That is, when the concentration immediately before the heating amount control valve 21 closes is, for example, 90% when the concentration of the concentrated liquid becomes the set value, the opening at the time of restarting the heating is set to 90 × 0.6 = 54 [%]. . As a result, the heating amount control valve 21 is throttled to an opening smaller than the opening at the time of the previous heating stop, the amount of gas supplied to the burner 1B decreases, and the heating amount decreases.

The second timer device 33 counts the time after the above-mentioned reset, that is, the time after the heating amount control valve 21 is opened and the combustion is started. As described above, when the amount of heating of the high-temperature regenerator 1 is reduced, the amount of refrigerant vapor generated in the high-temperature regenerator 1 is reduced, and the absorbent is not concentrated more than before the operation of the high-temperature regenerator 1 is stopped. As a result, the amount of the absorbent flowing from the high-temperature regenerator 1 to the low-temperature regenerator 2 increases, and the concentration of the absorbent decreases. Further, the absorption of the refrigerant vapor in the absorber 5 continues, the concentration of the dilute absorption liquid flowing from the absorber 5 to the high-temperature regenerator decreases, and the concentration of the absorption liquid circulating in the absorption refrigerator decreases. When the regeneration temperature of the low-temperature regenerator also decreases, the concentration of the concentrated liquid calculated by the concentration calculation device 30 also decreases.

When a second predetermined time, for example, 10 minutes, has elapsed since the high-temperature regenerator 1 resumed operation as described above, the second timer device 33 counts up and outputs a signal to the capacity control device 31. To reset. The capacity control device 31 operates upon input of a signal, and compares the concentrated solution concentration calculated by the concentration calculation device 30 with a set value. When the concentration of the concentrated liquid is equal to or lower than the set value, an open / close signal is output to the heating amount control valve 21 based on the cold water outlet temperature from the evaporator 4. As a result, thereafter, the opening of the heating amount control valve 21 is controlled according to the cold water outlet temperature.

When the concentration of the concentrated liquid calculated by the concentration calculating device 30 is higher than the set value when the second predetermined time has elapsed, the capacity control device 31 outputs an operation stop signal of the absorption refrigerator, The control device 27 outputs a close signal to the on-off valve 21A, the gas supply to the gas burner 20 stops, and the operation of the high-temperature regenerator 1 stops. Further, the control device 27 outputs an operation stop signal to the refrigerant pump 19 to stop the operation of the refrigerant pump 15. Further, the control device 27 outputs an operation signal to the absorbent pump 15 for a predetermined time after the high-temperature regenerator 1 is stopped,
After performing the so-called dilution operation by circulating the absorbent, an operation stop signal is output to the absorbent pump 15. Therefore, the operation of the absorbent pump 15 is also stopped.

Further, when the second predetermined time has elapsed, when the concentration of the concentrated solution is higher than the set value, the capacity control device 31 outputs a signal to the display 34 and the buzzer 35, and the capacity control device 31 provides, for example, a signal provided on the display 34. The light emitting element flashes and the buzzer 35 sounds to notify the administrator of the absorption refrigerator of the abnormality.
According to the embodiment of the present invention, when the concentration of the concentrated liquid reaches the set value, the capacity control device 31 operates, the gas burner 20 of the high-temperature regenerator 1 stops the combustion, and the high-temperature regeneration is performed for the first predetermined time. With the operation of the vessel 1 stopped, the absorbent pump 15 continues to operate, the diluted absorbent circulates, and the concentration of the absorbent gradually decreases. The refrigerant pump 19 continues to operate, and the cold water cooled by the evaporator 4 is supplied to the load. As a result, the concentration of the concentrated solution decreases in a short time, and crystallization of the concentrated solution can be avoided.

When the first predetermined time has elapsed since the operation of the high-temperature regenerator 1 was stopped, the capacity control device 31 outputs an open signal to the heating amount control valve 21, and the opening degree of the heating amount control valve 21 becomes Since the opening degree is set to be smaller than the opening degree immediately before the stop of the heating, for example, 60% of the opening degree immediately before the stop of the heating for the second predetermined time, even when the heating is restarted, the concentration of the absorbent can be concentrated regardless of the chilled water outlet temperature. The speed is reduced immediately before the stop of the heating, the concentration of the absorbing solution can be kept low continuously, and the crystallization of the concentrated solution can be reliably avoided.

Further, the concentration of the concentrated liquid increases and the high temperature regenerator 1
Before the combustion of the gas burner 20 is throttled, the combustion of the gas burner 20 is stopped, the operation of the high-temperature regenerator 1 is stopped for a first predetermined time, the absorbent is circulated to dilute the concentrated liquid, and the concentration of the concentrated liquid is reduced. Since the temperature of the high-temperature regenerator 1 is rapidly lowered, the set value of the concentrated liquid concentration when the operation of the high-temperature regenerator 1 is stopped and thereafter when the high-temperature regenerator 1 is operated with a reduced heating amount can be set close to the crystal precipitation concentration. As a result, a margin between the crystal deposition concentration and the set value can be increased as compared with the conventional control in which the heating amount is reduced for a predetermined time without stopping the combustion of the gas burner 20 when the concentration of the concentrated liquid reaches the set value. In addition, the operating range based on the cold water outlet temperature of the high-temperature regenerator 1 can be widened, and crystallization of the absorbing liquid can be avoided.

Further, when the second predetermined time has elapsed,
When the concentration of the concentrated liquid calculated by the concentration calculation device 30 is higher than the set value, the capacity control device 31 outputs an operation stop signal of the absorption refrigerator, outputs a close signal to the on-off valve 21A, and outputs the gas to the gas burner 20. The supply stops, and the operation of the high-temperature regenerator 1 stops. As a result, subsequent concentration of the absorption liquid can be avoided, and crystallization of the concentrated liquid due to equipment failure such as a decrease in the absorption liquid circulation path of the absorption refrigerator, particularly the low-temperature regenerator, etc., can be prevented. It can be avoided reliably.

Further, when the second predetermined time has elapsed, and when the concentration of the concentrated liquid is higher than the set value, the capacity control device 31 outputs a signal to the display 34 and the buzzer 35, and outputs the signal to the display 34, for example. Since the light-emitting element flashes and the buzzer 35 sounds to notify the administrator of the absorption refrigerator of the abnormality, the administrator can quickly know the concentration abnormality of the absorption liquid, and distinguish it from other abnormality or failure. You can check the absorption refrigerator. As a result, the maintenance and inspection work can be simplified.

Hereinafter, embodiments of the present invention will be described. The detailed description of the same configuration as the above embodiment is omitted. FIG. 2 is a block circuit diagram of a control device 41 according to claims 6 and 7.
Is further provided with a third timer device 42 and a counter 43.

During the operation of the absorption refrigerator, after the concentration of the concentrated liquid reaches the set value and the operation of the high-temperature regenerator 1 is stopped for the first predetermined time, as in the above embodiment, the operation is continued for the second predetermined time. The high-temperature regenerator 1 is operated with the heating amount of the high-temperature regenerator 1 smaller than immediately before the previous stop. After a second predetermined time has elapsed,
When the concentration of the concentrated liquid is higher than the set concentration,
1 outputs a close signal to the on-off valve 21A, the gas supply to the gas burner 20 is stopped, and the operation of the high temperature regenerator 1 is stopped.
Then, the capacity control device 31 outputs a signal to the third timer device 42, and the third timer device 42 starts counting. The capacity control device 31 outputs a signal to the counter 43, and the counter 43 counts one stop. While the third timer device 42 is operating, the absorbent pump 15
The operation is continued, and the concentration of the absorbing liquid further decreases by circulating the dilute liquid. The refrigerant pump 19 continues to operate, and the refrigerant separates and evaporates due to the residual capacity of the high-temperature regenerator 1.
To the load.

When a third predetermined time longer than the first predetermined time, for example, 10 minutes, has elapsed since the high-temperature regenerator 1 stopped operating and the third timer 42 started operating, the third timer 42 Counts up and outputs the signal to the capacity control device 3.
Output to 1. The capacity control device 31 compares the concentration of the concentrated liquid with the set value, and when the concentration of the concentrated liquid is lower than the set value, restarts the operation of the high temperature regenerator 1 and starts the normal operation of the absorption refrigerator. On the other hand, when the concentration of the concentrated liquid is equal to or higher than the set value, the capacity control device 31 does not restart the operation of the high-temperature regenerator 1 and outputs a signal to the third timer device 42 and the counter 43. The third timer device 42 is reset by this signal and starts counting again. The counter 43 counts the number of stop times twice. While the third timer device 42 is operating, the absorbent pump 15 and the refrigerant pump 19 continue to operate as described above.

When the third predetermined time elapses again after the high-temperature regenerator 1 stops operating and the third timer device 42 starts operating, the third timer device 42 counts up and outputs a signal to the capacity control device. Output to 31. The capacity control device 31 compares the concentration of the concentrated liquid with the set value, and when the concentration of the concentrated liquid is lower than the set value, restarts the operation of the high temperature regenerator 1 and starts the normal operation of the absorption refrigerator. On the other hand, when the concentration of the concentrated liquid is equal to or higher than the set value, the capacity control device 31
Is not restarted, a signal is output to the counter 43, and the counter 43 counts the number of stop times, which is a preset predetermined number of times, three times. Therefore, the counter 43 outputs a signal to the capacity control device 31, the capacity control device 31 outputs a stop signal of the absorption refrigerator based on the signal from the counter 43, and the control device 27 closes the on-off valve 21A. The signal is continuously output, the gas is not supplied to the gas burner 20, and the operation of the high-temperature regenerator 1 is stopped. The control device 27
Outputs an operation stop signal to the refrigerant pump 19 to stop the operation of the refrigerant pump 15. Further, the controller 27 outputs an operation signal to the absorbent pump 15 for a predetermined time after the high-temperature regenerator 1 is stopped, circulates the absorbent and performs a so-called dilution operation, and then outputs an operation stop signal to the absorbent pump 15. I do. Therefore, the operation of the absorbent pump 15 is also stopped.

According to the above embodiment, if the concentration of the concentrated liquid is equal to or higher than the set value after the lapse of the second predetermined time, the high-temperature regenerator 1
Is stopped for the third predetermined time longer than the first predetermined time, which is the previous heating stop time, so that the diluted liquid can be circulated for a longer time to further reduce the concentration of the absorbing liquid, especially the concentrated liquid. On the other hand, when the concentration of the concentrated liquid becomes lower than the set value, the operation stability of the absorption refrigerator can be improved while the operation of the absorption refrigerator is stopped and the operation is continued.

Further, the number of operation stoppages after the high-temperature regenerator 1 stops operation is counted, and the operation of the high-temperature regenerator 1 is only stopped until the count reaches a predetermined number. The operation of the pump 19 is continued to supply chilled water to the load, and when the number of times reaches a predetermined number, the operation of the absorption chiller is stopped. Therefore, the operation of the absorption chiller is continued as much as possible, and the supply of chilled water to the load is performed. , The generation of crystals of the absorption liquid in the absorption refrigerator can be avoided.

It should be noted that the present invention is not limited to the above embodiment, but can be variously implemented without departing from the gist of the present invention. For example, in the above embodiment,
In FIG. 1, the single effect absorption refrigerator has been described.
Even when the present invention is implemented in a double-effect absorption refrigerator,
The same functions and effects as those of the above embodiments can be obtained.

[0040]

According to the present invention, there is provided a method for controlling an absorption refrigerator as described above. According to the first aspect of the present invention, when the concentration of a concentrated solution rises to a set value, the regenerator is heated once. After the first predetermined time has elapsed, heating of the regenerator is started, and when the heating of the regenerator is started, the heating amount of the regenerator is set to a heating amount smaller than the heating amount at the time when the concentration of the concentrated liquid reaches the set value. Since the concentration is controlled for the second predetermined time, the concentration of the concentrated solution is increased and the heating is stopped before the amount of heating of the regenerator is reduced, the concentrated solution is diluted, the concentration of the concentrated solution is rapidly decreased, and the regeneration is performed. The set value of the concentration of the concentrated liquid when the operation of the vessel is stopped and thereafter when the regenerator is operated with a reduced heating amount can be set close to the crystal precipitation concentration. As a result, the margin between the crystal deposition concentration and the set value can be made smaller than in the conventional control in which the heating amount is reduced for a predetermined time when the concentration of the concentrated liquid reaches the set value, and the chilled water outlet of the regenerator can be reduced. Widen operating range based on temperature,
In addition, crystals of the absorbing solution can be avoided.

According to the second aspect of the present invention, when the concentration of the concentrated solution increases and reaches the set value, the heating of the regenerator is temporarily stopped, and then after the first predetermined time elapses, the heating of the regenerator is stopped. When the heating of the regenerator is started, the heating amount of the regenerator is controlled for a second predetermined time by the heating amount obtained by multiplying the heating amount at the time when the concentration of the concentrated liquid reaches the set value by a value smaller than 1. Stop heating before reducing the heating amount of the regenerator due to the increase in the concentration of the liquid, sharply reduce the concentration of the concentrated liquid, and when stopping the operation of the regenerator, and then operating by reducing the heating amount of the regenerator The set value of the concentration of the concentrated solution can be set close to the concentration of crystal precipitation. As a result, it is possible to reduce the margin between the crystal precipitation concentration and the set value as compared with the conventional control such that the heating amount is reduced for a predetermined time without stopping the heating when the concentration of the concentrated solution reaches the set value, The operating range based on the cold water outlet temperature of the regenerator 1 can be widened, and crystals of the absorbing liquid can be avoided. In addition, during the second predetermined time, the cooling water can be supplied to the load by operating the regenerator while the heating amount is reliably suppressed to be smaller than the heating amount immediately before the stop of the heating.

According to the third aspect of the present invention, when the concentration of the concentrated solution increases and reaches the set value, the heating of the high-temperature regenerator is temporarily stopped, and after the first predetermined time has elapsed, the heating of the regenerator is stopped. At the start of heating of the regenerator, the opening degree of the control valve is controlled to an opening degree obtained by multiplying the opening degree when the concentration of the concentrated liquid reaches the set value by a value smaller than 1 for a second predetermined time, Stop heating the regenerator before the concentration of the concentrated liquid rises and reduce the opening of the control valve, sharply decrease the concentration of the concentrated liquid, stop the operation of the regenerator, and then open the control valve , The set value of the concentration of the concentrated liquid when the operation is narrowed down can be set close to the crystal precipitation concentration. As a result, it is possible to reduce the margin between the crystal precipitation concentration and the set value as compared with the conventional control such that the heating amount is reduced for a predetermined time without stopping the heating when the concentration of the concentrated solution reaches the set value, The operating range based on the chilled water outlet temperature of the regenerator can be widened, and crystallization of the absorbent can be avoided. In the second predetermined time, the regenerator can be operated to supply the cooling water to the load while the opening of the control valve is reliably kept smaller than the opening just before the stop of the heating.

According to the fourth aspect of the present invention, the second
If the concentration of the concentrated liquid is equal to or higher than the set value when the predetermined time elapses, the operation of the absorption refrigerator is stopped, so that subsequent concentration of the absorption liquid can be avoided, and the absorption refrigerator can be absorbed. Crystallization of the concentrated liquid due to a failure of the device such as a decrease in the amount of circulation of the concentrated liquid can be avoided.

According to the fifth aspect of the present invention, an indicator is provided, and when the second predetermined time has elapsed, if the concentration of the concentrated liquid is higher than a set value, the operation of the absorption refrigerator is stopped. In addition, since the display and the operation of the display are operated, the administrator can quickly know the concentration abnormality of the absorbing solution, and can inspect the absorption refrigerator in distinction from other abnormality or failure. As a result, the maintenance and inspection work can be simplified.

According to the sixth aspect of the present invention, the second
When the concentrated liquid concentration is equal to or higher than the set value when the predetermined time elapses, the heating of the regenerator is stopped after the second predetermined time elapses for a third predetermined time longer than the first predetermined time. The liquid can be circulated for a longer period of time to further reduce the concentration of the absorbing liquid, particularly the concentrated liquid.When the concentration of the concentrated liquid becomes lower than the set value, the operation of the absorption refrigerator can be avoided while stopping the operation. By continuing, the margin of the concentrated liquid can be further reduced, and the operation stability of the absorption refrigerator can be further improved.

Further, according to the present invention, when the second predetermined time elapses and the concentration of the concentrated liquid is equal to or higher than the set value, the regenerator is heated after the second predetermined time elapses. First
The third predetermined time longer than the predetermined time is stopped, and thereafter, every time the third predetermined time elapses, when the concentrated liquid concentration is equal to or more than the set value, the heating of the regenerator is stopped,
When the number of heating stops of the regenerator reaches a predetermined number, the operation of the absorption chiller is stopped, so that the operation of the absorption chiller is continued as much as possible, and while the supply of chilled water to the load is continued, the absorption chiller is operated. Of the absorbing solution can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an absorption refrigerator showing an embodiment of claims 1 to 5 of the present invention.

FIG. 2 is a block diagram of a control device showing an embodiment of claims 6 and 7 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High temperature regenerator 2 Low temperature regenerator 3 Condenser 4 Evaporator 5 Absorber 15 Absorbent pump 19 Refrigerant pump 21 Heating amount control valve 21A Open / close valve

Claims (7)

(57) [Claims] 1. A regenerator, a condenser, an evaporator, an absorber and the like are connected by piping to form a circulation path for a refrigerant and an absorbing liquid, and a heating amount of the regenerator is controlled based on a temperature of a cold water outlet of the evaporator. In the control method of the absorption refrigerator, when the concentration of the concentrated solution rises to the set value, the heating of the regenerator is temporarily stopped, and then after a first predetermined time has elapsed, the heating of the regenerator is started,
A method for controlling the amount of heating of the regenerator for a second predetermined time at a time when the heating of the regenerator is started to be smaller than the amount of heating when the concentration of the concentrated liquid has reached the set value. . 2. A regenerator, a condenser, an evaporator, an absorber, and the like are connected by piping to form a circulation path for a refrigerant and an absorbing liquid, and a heating amount of the regenerator is controlled based on a cold water outlet temperature of the evaporator. In the control method of the absorption refrigerator, when the concentration of the concentrated solution rises to the set value, the heating of the regenerator is temporarily stopped, and then after a first predetermined time has elapsed, the heating of the regenerator is started,
When the heating of the regenerator is started, the heating amount of the regenerator is controlled to a heating amount obtained by multiplying the heating amount when the concentration of the concentrated liquid reaches the set value by a value smaller than 1 for a second predetermined time. Control method of a refrigerator. 3. A control valve provided in a pipe connected to a regenerator, a condenser, an evaporator, an absorber and the like to form a circulation path of a refrigerant and an absorbing liquid and connected to the regenerator to flow a heat source fluid. In the control method of the absorption refrigerator in which the opening degree is controlled based on the cold water outlet temperature of the evaporator, when the concentration of the concentrated liquid increases and reaches a set value, the heating of the regenerator is temporarily stopped, and then the first method is performed. After the elapse of a predetermined time, heating of the regenerator is started. At the start of heating of the regenerator, the opening of the control valve is set to the opening obtained by multiplying the opening at the time when the concentration of the concentrated liquid reaches the set value by a value smaller than 1. 2. A method for controlling an absorption refrigerator, wherein the control is performed for a predetermined time. 4. The method according to claim 1, wherein when the second predetermined time has elapsed, if the concentration of the concentrated liquid is equal to or higher than a set value, the operation of the absorption refrigerator is stopped. The method for controlling an absorption refrigerator according to claim 3. 5. The method according to claim 1, further comprising the step of: stopping the operation of the absorption chiller and operating the display when the concentration of the concentrated liquid is equal to or higher than the set value when the second predetermined time has elapsed. The method of controlling an absorption refrigerator according to any one of claims 1, 2 and 3. 6. When the concentration of the concentrated liquid is equal to or more than a set value when the second predetermined time has elapsed, after the second predetermined time has elapsed, heating of the regenerator is performed for a third time longer than the first predetermined time. The method according to any one of claims 1, 2 and 3, wherein the operation is stopped for a predetermined time. 7. When the concentration of the concentrated liquid is equal to or more than a set value when the second predetermined time has elapsed, the regenerator is heated for a third time longer than the first predetermined time after the second predetermined time has elapsed. For a predetermined time, and thereafter, every time a third predetermined time elapses, the concentration of the concentrated liquid is compared with the set value. When the concentration of the concentrated liquid is equal to or more than the set value, the heating of the regenerator is stopped. 4. The method of controlling an absorption refrigerator according to claim 1, wherein the operation of the absorption refrigerator is stopped when a predetermined number of times is reached.