JP3326240B2 - 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 an absorption refrigerator, and more particularly to a control device for an absorption refrigerator which controls the heating amount of a regenerator based on a chilled water outlet.

[0002]

2. Description of the Related Art For example, Japanese Utility Model Publication No. Sho 62-6449 discloses that the amount of heating of a regenerator due to the temperature of a cooling water outlet of an evaporator is compensated for by the temperature of the cooling water at the inlet to the absorber, and the temperature of the cooling water gradually decreases. Discloses a control device for an absorption refrigerator that adjusts the opening of a fuel control valve by increasing the set value of a chilled water outlet temperature in accordance with the above.

For example, Japanese Patent Application Laid-Open No. 58-160783 discloses that the condensing pressure is calculated from the refrigerant condensing temperature of the condenser, or the condensing pressure is directly detected, and the concentration of the concentrated liquid is calculated from this pressure and the low temperature regeneration temperature. The outlet temperature of the low-temperature heat exchanger at which the temperature of the concentrated liquid becomes the lowest is separately calculated, and the difference between the crystal concentration of the absorbing liquid at this temperature and the calculated concentration of the concentrated liquid is defined as the concentration margin, and the concentration margin is set. A control device for an absorption refrigerator is disclosed in which the input of the heating source is increased when the value is larger than the set value, and the control is performed to decrease the input when the value is smaller than the set value.

[0004]

Problems to be Solved by the Invention
In the absorption chiller control device disclosed in Japanese Patent Publication No. 49, when the cooling water load increases when the cooling water inlet temperature is high, the temperature or pressure of the regenerator increases and the absorption chiller increases. Could be safely stopped. Also, when the outside air temperature is low and the cooling water inlet temperature is low, when the amount of heating in the regenerator is large and the concentration of the concentrated liquid flowing from the regenerator to the absorber is high, crystals may be generated. There has been a problem that the amount of heating in the regenerator is large and the fuel consumption of the regenerator is large.

In the control apparatus of the absorption refrigerator disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-160783, the input of the heating source of the regenerator is controlled based on the margin of concentrated liquid,
The input of the heating source is controlled based on the chilled water outlet temperature, and both control amounts are given to the heating amount control valve as the control amount of the heating source. Therefore, for example, when the chilled water outlet temperature has reached the set value, if the concentration of the concentrated solution increases and the concentration margin becomes smaller than the set value, the heating amount is reduced. However,
When the concentration becomes low, the refrigeration capacity becomes difficult to appear, so that the temperature of the cold water outlet temperature rises. Then, as the chilled water outlet temperature rises, the amount of heating is controlled so that the refrigeration capacity is increased. Then, the concentration of the concentrated solution increases, the concentration margin becomes small, and the danger of crystallization is not alleviated further.

As described above, it is difficult to establish control for simultaneously adjusting both the chilled water outlet temperature and the concentration allowance to the set values, and control with a priority is required.

[0007]

In order to solve the above-mentioned problems, the present invention connects a regenerator 4, a condenser 6, an evaporator 1, an absorber 2 and the like with a pipe, and determines a temperature of a cold water outlet of the evaporator 1 based on the temperature. In the control method of the absorption refrigerator in which the heating of the regenerator 4 is stopped and controlled at three positions of weak heating and strong heating, when the cooling water inlet temperature of the absorber 2 is higher than the high temperature set value or lower than the low temperature set value In some cases, the maximum heating position of the regenerator 4 is controlled based on the cooling water inlet temperature, and regeneration is performed based on the cooling water outlet temperature regardless of the cooling water inlet temperature until the heating of the regenerator 4 reaches the maximum position. Stop heating of vessel 4, weak heating,
An object of the present invention is to provide a control method of an absorption refrigerator controlled at three positions of strong heating.

When the concentration of the concentrated liquid rises to a predetermined concentration, the heating of the regenerator 4 is performed at predetermined time intervals when the concentration of the concentrated liquid reaches the predetermined concentration, It is intended to provide a control method of a collecting refrigeration machine that controls the heating position to a heating position having a smaller heating amount than the heating position at the time of becoming. Further, when the concentration of the concentrated solution rises to the predetermined concentration, the heating of the regenerator 4 is controlled to a heating position having a smaller heating amount than the heating position when the concentration of the concentrated solution reaches the predetermined concentration for a predetermined time. The present invention provides a method of controlling a machine.

[0009]

When the temperature of the cooling water rises above the high temperature set value, the maximum heating position of the regenerator 4 is limited to weak heating in response to the rise of the cooling water inlet temperature, and the cooling water outlet temperature is reduced. Even if the heating of the regenerator 4 based on the above becomes strong heating, the regenerator 4 performs the operation of weak heating, the heating of the absorbent in the regenerator 4 is suppressed, and the temperature or pressure of the regenerator 4 is greatly increased. Such a rise can be easily avoided, and the stoppage of the absorption refrigerator due to a rise in the cooling water temperature can be avoided.

When the temperature of the cooling water drops below the low temperature set value, the maximum heating position of the regenerator 4 is limited to weak heating in response to the cooling water inlet temperature drop. Even when the heating of the regenerator 4 based on the outlet temperature becomes a strong heating, the regenerator 4 performs a weak heating operation, the heating of the absorbing liquid in the regenerator 4 is suppressed, and the generation of refrigerant vapor is reduced. As a result, it is possible to prevent a significant increase in the concentration of the absorbing liquid returning from the regenerator 4 to the absorber, to avoid generation of crystals, and to reduce the operating cost of the absorption refrigerator.

When the concentration of the concentrated liquid increases and reaches a predetermined concentration, the combustion of the regenerator 4 is repeatedly controlled at a predetermined time interval between a heating position when the predetermined concentration is reached and a heating position lower than the heating position. The heating of the regenerator 4 is stopped based on the cold water outlet temperature, and controlled to one of three positions of weak heating and strong heating, and the heating is controlled to any position of weak heating or strong heating. Also, when the amount of heating of the absorbent in the regenerator 4 is reduced, the concentration of the absorbent is reduced, and the absorption of the refrigerant vapor in the absorber 2 is continued.
The concentration of the concentrated liquid returning from the filter to the absorber 2 becomes thin, and it becomes possible to prevent crystallization of the absorbing liquid.

Further, in the regenerator 4 in which the heating is controlled at three positions, when the concentration of the concentrated liquid rises to a predetermined concentration, the heating of the regenerator 4 is performed at the heating position when the concentration reaches the predetermined concentration and the heating position. The heating amount of the regenerator 4 is easily reduced by controlling the heating of the regenerator 4 to the two-position control among the three-position control at a predetermined time interval. It is possible to easily cope with an increase in the concentration of the concentrated solution.

Further, when the concentration of the concentrated liquid rises to a predetermined concentration, the combustion of the high-temperature regenerator 4 is controlled to a heating position lower than the heating position at the time when the concentration reaches the predetermined concentration. Based on the temperature, it is controlled to one of the three positions of stop, weak heating and strong heating. Even if the heating is controlled to any position of weak heating or strong heating, absorption by the regenerator 4 is performed. Since the amount of liquid heating decreases, the concentration of the absorbing liquid is quickly decelerated, and the absorption of the refrigerant vapor in the absorber 2 continues. It becomes possible to prevent crystallization of the liquid.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows that the refrigerant is, for example, water and an absorbing liquid (solution).
FIG. 1 is a schematic configuration diagram of an absorption refrigerator using a lithium bromide (LiBr) solution as an evaporator, 1 is an evaporator, 2 is an absorber, 3 is an evaporator absorber body (3) containing an evaporator 1 and an absorber 2. Less than,
4 is a high-temperature regenerator heated by a high-temperature heat source, 5A and 5B are first and second gas burners housed in the high-temperature regenerator 4, 6 is a low-temperature regenerator, 7 is a condenser, and 8 is a condenser. A low-temperature regenerator condenser body (hereinafter referred to as an upper body) housing the low-temperature regenerator 6 and the condenser 7, a low-temperature heat exchanger 9;
10 is a high-temperature heat exchanger, 11 to 15 are absorption liquid pipes, 1
6 is an absorption liquid pump, 17 and 18 are refrigerant pipes, 19 is a refrigerant circulation pipe, 20 is a refrigerant pump, 21A and 21B are gas pipes connected to the respective gas burners 5A and 5B,
22A and 22B are gas pipes 21A and 21B, respectively.
The first and second fuel control valves 23 provided in the middle of B are cold water pipes provided with the evaporator heat exchanger 24 in the middle,
Each is connected by piping as shown in FIG.

Reference numeral 25 denotes a cooling water pipe, and an absorber heat exchanger 26 and a condenser heat exchanger 27 are provided in the cooling water pipe 25. 28 is a cooling tower, 30
Denotes a cooling water pump, and the cooling tower 28 and the cooling water pump 3
A cooling circuit is formed by connecting 0 to the pipe. 3
1 is a first temperature detector which is a cold water outlet temperature detector provided on the outlet side of the evaporator 1 of the cold water pipe 23, and 32 detects the temperature of the cooling water provided on the absorber inlet side of the cooling water pipe 25. A second temperature detector. Reference numeral 33 denotes a control device constituted by a microcomputer, for example.
Operates by inputting temperature signals from the first and second temperature detectors 31 and 32 and outputs an open / close signal to the first and second fuel control valves 22A and 22B.

Hereinafter, the configuration of the control device 33 will be described. Reference numeral 34 denotes an input interface for inputting signals from the first and second temperature detectors 31 and 32, converting the signals, and outputting the converted signals to a central processing unit (hereinafter referred to as a CPU) 35; A storage device (hereinafter referred to as a ROM) in which a signal from the CPU 35 is input and an output interface for outputting a signal to the first and second fuel control valves 22A and 22B is designated by a reference numeral 37; A signal generator (hereinafter, referred to as CLOOCK) that outputs a signal every time, and a read / erasable storage device (hereinafter, referred to as RAM) 40 that stores the temperature detected by each temperature detector.

The ROM 36 stores the relationship between the cooling water inlet temperature having hysteresis as shown in FIG. 2 and the maximum heating amount position, and the cold water outlet temperature having hysteresis as shown in FIG. , The second fuel control valve 22A, 22B
Open / close signal to be output to, that is, the relationship with the heating amount is stored,
Here, the open / close signals output to the first and second fuel control valves 22A and 22B based on the chilled water outlet temperature are limited to the heating amount maximum position shown in FIG.

During the operation of the above-mentioned absorption chiller for supplying cold water, the refrigerant evaporated in the high-temperature regenerator 4 flows to the condenser 7 through the low-temperature regenerator 6 similarly to the conventional absorption chiller, and the heat exchanger is connected to the condenser. After being condensed and liquefied by exchanging heat with the cooling water flowing through 27, it flows to the evaporator 1 via the refrigerant pipe 18. Then, the refrigerant exchanges heat with water flowing through the evaporator heat exchanger 24 to evaporate, and the water flowing through the evaporator heat exchanger 24 is cooled by heat of vaporization.
Then, cold water circulates through the load. Further, the refrigerant evaporated in the evaporator 1 is absorbed by the absorbing liquid in the absorber 2. The absorption liquid whose concentration has been reduced by absorbing the refrigerant is sent to the high-temperature regenerator 4 via the low-temperature heat exchanger 9 and the high-temperature heat exchanger 10 by the operation of the absorption liquid pump 16. The absorbing liquid sent to the high-temperature regenerator 4 is heated to evaporate the refrigerant, and the medium-density absorbing liquid flows through the high-temperature heat exchanger 10 to the low-temperature regenerator 6. In the low-temperature regenerator 6, the absorbing liquid is heated by the refrigerant vapor flowing from the high-temperature regenerator 10 through the refrigerant pipe 17, and the refrigerant vapor is further separated to increase the concentration. The high-concentration absorbent is cooled down through the low-temperature heat exchanger 9 and sent to the absorber 2 where it is dispersed.

The control of the heating amount of the high-temperature regenerator 4 during the operation of the absorption refrigerator as described above will be described. The temperatures of the first and second temperature detectors 31 and 32 are temporarily stored in a RAM 38 via an input interface 34 and a CPU 35. Then, the cooling water inlet temperature and the cooling water inlet temperature stored in the RAM 38 are read into the CPU 35 at predetermined time intervals based on the signal from the CLOCK 40, and the relationship shown in FIG. Is read. And
The CPU 35 detects the first and second fuel control valves 22A, 22A from the above relationship between the detected chilled water outlet temperature and the chilled water temperature.
The opening and closing of B, that is, the heating amount is determined.

For example, in summer, before the outside air temperature rises, the cooling water inlet temperature detected by the second temperature detector 32 is, for example, 2
When the temperature is 8 ° C., as shown in FIG. 2, the maximum heating amount of the high temperature regenerator 4 is strong combustion, that is, when the heating amount is the maximum, both the second fuel control valves 22A and 22B are opened and the high temperature regenerator 4 is opened. Is controlled so that the absorption liquid is strongly heated. Therefore, based on the relationship between the cold water outlet temperature detected by the first temperature detector 31 and the relationship shown in FIG.
An open / close signal is output to the fuel control valves 22A and 22B, heating of the high-temperature regenerator 4 is stopped when both the first and second fuel control valves 22A and 22B are closed, and only the first fuel control valve 22A is opened and the first gas burner is opened. 3 of weak heating (combustion) by combustion of 5A, and strong heating (combustion) by combustion of first and second gas burners 5A and 5B by opening first and second fuel control valves 22A and 22B.
Controlled by position.

In the summer, the outside air temperature rises and the cooling tower 3
5, when the cooling water inlet temperature detected by the second temperature detector 32 becomes higher than the high temperature set value (for example, 34 ° C.), the control device 33 operates to regenerate the high temperature as shown in FIG. The maximum heating position of the heater 4 is limited to a state in which weak heating is performed, that is, the first fuel control valve 22A is opened and only the first gas burner 5A burns. Therefore, when the cooling water inlet temperature becomes higher than 34 ° C., the chilled water outlet temperature rises and becomes higher than the set temperature, and the heating position based on the chilled water outlet temperature is strongly heated, that is, the first and second fuel control valves 22A. , 22B is limited to weak heating by opening only the first fuel control valve 22A. Then, the heating position of the high-temperature generator 4 is controlled to be weakly heated or stopped (extinguished) according to the cold water outlet temperature, so that the temperature or pressure of the high-temperature regenerator 4 is prevented from increasing significantly.

Further, when the outside air temperature rises and the cooling capacity of the cooling tower 35 decreases, and the cooling water inlet temperature detected by the second temperature detector 32 becomes higher than a set value (for example, 38 ° C.),
The control device 33 operates to switch the heating amount maximum position of the high-temperature regenerator 4 to stop as shown in FIG. 2, and the first and second fuel control valves 22A and 22B are opened and closed to heat both the valves. It is limited to a state where it stops. Therefore, when the cooling water inlet temperature becomes higher than 38 ° C., the cold water outlet temperature rises and becomes higher than the set temperature, and the heating position based on the cold water outlet temperature is weakly or strongly heated, that is, the first and second fuels. The opening / closing control of the control valves 22A and 22B is performed by opening only the first fuel control valve 22A or the first and second fuel control valves 22A and 22B.
B, both the first and second fuel control valves 22A, 22B are limited to a closed stop state when both valves are in the open position, and even when the chilled water outlet temperature changes, the high temperature regenerator 4
The heating position is controlled to be stopped, so that the temperature or pressure of the high-temperature regenerator 4 is prevented from significantly increasing.

Thereafter, when the outside air temperature decreases and the cooling capacity of the cooling tower 35 improves, and the cooling water inlet temperature detected by the second temperature detector 32 becomes lower than a set value (for example, 36 ° C.),
The controller 33 operates to switch the maximum heating amount of the high-temperature regenerator 4 to weak heating as shown in FIG. 2, and to heat the high-temperature regenerator 4 based on the cold water outlet temperature detected by the first temperature detector 31. Is a stop in which both the first and second fuel control valves 22A and 22B are closed, and only the first fuel control valve 22A is open and the first
Weak heating due to combustion of the gas burner 5A, the first and second fuel control valves 22A and 22B are opened, and the first and second gas burners 5A,
It is controlled to three positions of strong heating by combustion of 5B.

Thereafter, when the outside air temperature further decreases and the cooling capacity of the cooling tower 35 improves, and the cooling water inlet temperature detected by the second temperature detector 32 becomes lower than a set value (for example, 18 ° C.), the controller 2, the maximum heating amount of the high-temperature regenerator 4 is switched to the weak heating as shown in FIG. 2, the first fuel control valve 22A is opened, and the state where only the first gas burner 5A burns is limited. Therefore, when the cooling water inlet temperature becomes lower than 18 ° C., the heating position of the high temperature generator 4 is controlled to be weakly heated or stopped according to the cold water outlet temperature,
The fuel consumption of the high-temperature regenerator 4 can be reduced, and even when the cold water outlet temperature rises, the heating position of the high-temperature regenerator 4 is limited to weak heating, and the amount of refrigerant vapor separated in the high-temperature regenerator 4 And the concentration of the absorbing solution flowing out of the high-temperature regenerator 4 decreases, and the concentration of the absorbing solution flowing out of the low-temperature regenerator 6 can be reduced, thereby avoiding the generation of crystals in the low-temperature heat exchanger 9 and the like. Can be.

In the above embodiment, two gas burners are provided in the high-temperature regenerator 4, and the first and second fuel control valves 22A and 22B are provided in the first and second fuel pipes 21A and 21B connected to each gas burner. The three-position control of stop, weak heating and strong heating is performed by opening and closing the respective fuel control valves.
A gas burner having the combined capacity of A and 5B is provided, and the amount of gas supplied to the gas burner is switched to 0%, 50% and 100% by opening the control valve provided in the fuel pipe. The heating of the regenerator 4 may be stopped, and the heating may be controlled to three positions of weak heating and strong heating.

Further, even when the heat source of the high-temperature regenerator 4 is, for example, high-temperature and high-pressure steam, the heater provided in the high-temperature regenerator 4 is divided into two parts, and the steam supplied to each heater is separated by a steam gas burner. The control may be performed in the same manner as in the case of. Further, the opening degree of the control valve for controlling the steam supply amount by providing one heater is switched between 0%, 50% and 100%, and the heating of the high-temperature regenerator 4 is stopped. May be controlled.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and the detailed description thereof will be omitted. Reference numeral 42 denotes a third temperature detector provided in the condenser 7 for detecting the condensation temperature of the refrigerant, and reference numeral 43 denotes a fourth temperature detector provided on the outlet side of the low-temperature regenerator 6 for detecting the regeneration temperature.
Reference numeral 44 denotes a control device which receives signals from the first, third and fourth temperature detectors 31, 42 and 43 and converts the signals in the same manner as the control device shown in the first embodiment. Interface 34 for outputting to a central processing unit (hereinafter referred to as CPU) 35, and a storage device (hereinafter referred to as ROM) storing a control program and the like relating to the present invention.
36, an output interface 37 for inputting a signal from the CPU 35 and outputting a signal to the first and second fuel control valves 22A and 22B, and a signal generator (hereinafter referred to as a CLOOCK) for outputting a signal at predetermined time intervals. 38, a timer 39 for counting a predetermined time, a readable and erasable storage device (hereinafter referred to as RAM) 4 for storing the temperature detected by each temperature detector.
0. Further, reference numeral 45 denotes a display, and 46 denotes a buzzer. The concentration of the absorbent having a high concentration returning from the low-temperature regenerator 6 to the absorber 2 (hereinafter referred to as "concentrated liquid concentration") exceeds a predetermined concentration. If the density is higher than the threshold, a signal is output from the control device 44 to the display 45 and the buzzer 46, and the display 45 is turned on and the buzzer 46 sounds.

The ROM 36 stores a cold water outlet temperature and an open / close signal output to the first and second fuel control valves 22A and 22B as shown in FIG. The relationship with the heating amount is stored, and the condensation temperature T1 detected by the third temperature detector 42 and the fourth temperature detector 43
From the regeneration temperature T2 of the low temperature regenerator 6 detected by
Is an approximate expression for calculating

[0029]

(Equation 1)

Is stored. In the approximate expression, a1,
a2, a3 and a4 are constants. During the operation of the absorption refrigerator configured as described above, the absorption liquid and the refrigerant circulate, and the chilled water is supplied from the evaporator 1 to the load, similarly to the absorption refrigerator described in the first embodiment. At this time, the control device 33 receives a temperature signal from the first temperature detector 31 and based on the relationship shown in FIG. 3, the first and second fuel control valves 22A and 22B.
The heating of the high-temperature regenerator 4 is stopped by switching to three positions of weak heating and strong heating.

The CPU 35 of the control device 33 calculates the condensation temperature T1 detected by the third and fourth temperature detectors 42 and 43.
The concentration of the concentrated solution is calculated from the temperature, the regeneration temperature T2, and the approximate expression. Then, the concentration of the concentrated liquid calculated by the CPU 35 is compared with a predetermined concentration set in advance, and when the concentration of the concentrated liquid increases and reaches the predetermined concentration, the heating of the high-temperature regenerator 4 at that time and the heating Heating control in which lower heating is repeated at predetermined time intervals is performed. That is, when the concentration of the concentrated liquid reaches a predetermined concentration, an open signal is output to the first and second fuel control valves 22A and 22B, and both the first and second gas burners 5A and 5B are burning. When the heating of the regenerator 4 is, for example, at the strong heating position, the controller 33 controls the second fuel control valve 22
B repeatedly outputs a close signal and an open signal every predetermined time (for example, one minute), and continuously outputs an open signal to the first fuel control valve 22A, as shown in FIG. 4
Is controlled at two positions of weak heating and strong heating at predetermined time intervals. When the concentration of the concentrated liquid reaches a predetermined concentration, an open signal is output to the first fuel control valve 22A, only the first gas burner 5A is burning, and the heating of the high-temperature regenerator 4 is, for example, weak heating. In the case of the position, the control device 33 repeatedly outputs the close signal and the open signal to the first fuel control valve 22A every first predetermined time (for example, one minute), and as shown in FIG. The heating of the vessel 4 is first in two positions: stop and weak heating.
Is controlled every predetermined time. Further, when the concentration of the concentrated liquid reaches a predetermined concentration, the timer 39 starts counting based on a signal from the CPU 53.

As described above, the heating of the high-temperature regenerator 4 is controlled so that the weak heating and the strong heating are repeated at every first predetermined time, or the weak heating and the stop are repeated at every first predetermined time. In addition, the amount of heating of the absorbing liquid in the high-temperature regenerator 4 is reduced, the amount of refrigerant vapor generated in the high-temperature regenerator 4 is reduced, and the concentration of the absorbing liquid is reduced. Further, as the amount of the absorbing liquid flowing from the high-temperature regenerator 4 to the low-temperature regenerator 6 increases, the temperature of the absorbing liquid also decreases. Further, the absorption of the refrigerant vapor in the absorber 2 continues, and the concentration of the absorbing liquid decreases.

When a second predetermined time (for example, 10 minutes) elapses after the concentration of the concentrated liquid reaches the predetermined concentration, the timer 39 outputs a signal, and the CPU 35 which has received the signal outputs the signal.
Then, the concentration of the concentrated liquid at the time when the signal is input from the controller is compared with the predetermined concentration. When the concentration of the concentrated liquid is lower than the predetermined concentration, C
PU 35 outputs an open / close signal based on the chilled water outlet temperature,
The combustion control of the high temperature regenerator 4 as shown in FIG. 3 is performed.

When the concentration of the concentrated liquid after the lapse of the second predetermined time is equal to or higher than the predetermined concentration, the CPU 35 outputs a close signal to the first and second fuel control valves 22A and 22B, and the writing valve is closed to close the first fuel control valve. Then, the combustion of the second gas burners 5A and 5B is stopped. Then, the absorbent pump 16 continues to operate, the absorbent flows from the absorber 2 to the high-temperature regenerator 4 and the low-temperature regenerator 6 sequentially, and a normal dilution operation is performed. The CPU 35 is connected to the display 4
An ON signal is output to the buzzer 5 and the buzzer 46, and based on the signal from the control device 33, the display 45 lights up and the buzzer 46 sounds. According to the second embodiment in which the absorption chiller stops when the dilution operation is completed, according to the second embodiment, when the concentration of the concentrated liquid increases and reaches a predetermined concentration, the control device 33 operates to heat the high-temperature regenerator 4. Is repeatedly controlled at a first predetermined time interval between a heating position when the concentration reaches a predetermined concentration and a heating position less than the heating position, and stops the heating of the high-temperature regenerator 4 based on the cold water outlet temperature; Since the heating is controlled to any one of the three heating positions, and the heating is controlled to either the weak heating or the strong heating, the amount of heating of the absorbent in the high-temperature regenerator 4 is reduced. While the concentration of the liquid is reduced, the absorption of the refrigerant vapor in the absorber 2 continues, and the concentration of the concentrated liquid returning from the high-temperature regenerator 4 to the absorber 2 via the low-temperature regenerator 6 decreases. As a result, crystallization of the absorbing solution can be prevented.

In the high-temperature regenerator 4 in which the heating is controlled at three positions, when the concentration of the concentrated solution rises to a predetermined concentration, the heating of the high-temperature regenerator 4 is performed at the heating position when the predetermined concentration is reached. The heating position of the high-temperature regenerator 4 is repeatedly controlled to a heating position smaller than the heating position at every first predetermined time. Can be easily reduced, and it is possible to easily cope with an increase in the concentration of the concentrated solution.

When the concentration of the concentrated liquid is equal to or higher than the predetermined concentration when the second predetermined time has elapsed after the concentration of the concentrated liquid has increased to the predetermined concentration, the operation of the high-temperature regenerator 4 is stopped. Therefore, it is possible to prevent the concentration of the concentrated liquid from increasing due to, for example, the retention of non-condensable gas or the decrease in the temperature of the cooling water, thereby avoiding the generation of crystals. Further, when the concentration of the concentrated absorbent is lower than the prescribed concentration after the lapse of the second prescribed time, the three-position control of the heating of the high-temperature regenerator 4 based on the cold water outlet temperature is performed again, and the concentration of the concentrated liquid is temporarily reduced. It is possible to cope with the rise without stopping the absorption refrigerator, and as a result, it is possible to avoid a large rise in the chilled water outlet temperature.

In the second embodiment, for example, the gas burners 5A, 5A,
One gas burner having the capacity corresponding to B is provided, and the amount of gas supplied to the gas burner is switched between 0%, 50%, and 100% by opening the control valve provided in the fuel pipe.
The combustion of the high-temperature regenerator 4 may be stopped, controlled to three positions of weak heating and strong heating. Further, the heating source of the high temperature regenerator 4 is not limited to the upper gas.

Hereinafter, a third embodiment will be described. In the third embodiment, the three-position control of the heating of the high-temperature regenerator 4 based on the cold water outlet temperature is the same as in the first and second embodiments. Is different in the heating control of the high temperature regenerator 4. Therefore, the third embodiment will be described with reference to FIG. 4 described in the second embodiment.

When the concentration of the concentrated liquid reaches a predetermined concentration, the control device 33 operates to move the heating of the high-temperature regenerator 4 to a heating position smaller than the heating position at that time, for example, at a second predetermined position irrespective of a change in the chilled water outlet temperature. Control the time. That is, when the heating of the high-temperature regenerator 4 when the concentration of the concentrated liquid reaches the predetermined concentration is, for example, strong heating, the heating of the high-temperature regenerator 4 is limited to the weak heating regardless of the change in the outlet temperature of the cold water. You. When the heating of the high-temperature regenerator 4 when the concentration of the concentrated liquid reaches a predetermined concentration is, for example, weak heating, each gas burner 5 of the high-temperature regenerator 4 is heated.
The supply of fuel to A and 5B is shut off, and the heating of the high-temperature regenerator 4 is stopped. Then, the amount of refrigerant vapor generated in the high-temperature regenerator 4 is rapidly reduced.

According to the third embodiment, when the concentration of the concentrated liquid rises to the predetermined concentration, the control device 33 operates, and the heating of the high-temperature regenerator 4 starts from the heating position when the predetermined concentration is reached. The heating of the high-temperature regenerator 4 is controlled based on the temperature of the cold water outlet, and is controlled to a small heating position.
When the heating is controlled to either the weak heating or the strong heating, the heating amount of the absorbing liquid in the high-temperature regenerator 4 is reduced. And the absorption of the refrigerant vapor in the absorber 2 continues, and the concentration of the concentrated liquid returning from the high temperature regenerator 4 to the absorber 2 via the low temperature regenerator 6 decreases. As a result, crystallization of the absorbing solution can be prevented.

[0041]

According to the present invention, there is provided a control apparatus for an absorption refrigerator configured as in the above embodiment. According to the first aspect of the present invention, when the cooling water inlet temperature of the absorber is higher than a high temperature set value. Or, when the temperature is lower than the low temperature set value, the maximum heating position of the regenerator is controlled based on the cooling water inlet temperature, and the cooling water outlet is independent of the cooling water inlet temperature until the heating of the regenerator reaches the maximum position. Heating of the regenerator is stopped based on the temperature, and control is performed at three positions of weak heating or strong heating. Restriction is imposed on the three-position control of heating of the regenerator to regenerate when the temperature of the cooling water rises. A large increase in the temperature or pressure of the chiller can be easily avoided, and as a result, the stop of the absorption chiller due to an increase in the cooling water temperature can be avoided, and the operation of the absorption chiller can be stabilized. Can be.

When the temperature of the cooling water drops,
The amount of heating of the regenerator can be reduced in preference to the control by the chilled water outlet temperature, and as a result, it is possible to prevent a significant increase in the concentration of the absorbing solution, to avoid the generation of crystals, and to reduce the absorption chiller. Operating cost can be reduced.
According to the second aspect of the present invention, when the concentration of the concentrated liquid rises to the predetermined concentration, the heating of the regenerator is performed at predetermined time intervals at a heating position when the concentration of the concentrated liquid reaches the predetermined concentration, and Since the heating position is controlled to a heating position with a smaller heating amount than the heating position when the liquid concentration reaches the predetermined concentration, heating of the regenerator is stopped based on the cold water outlet temperature, and any one of the three positions of weak heating and strong heating. When the heating is controlled to either the weak heating or the strong heating, crystallization of the absorbing liquid can be prevented.

In the regenerator whose heating is controlled at three positions, when the concentration of the concentrated liquid rises to a predetermined concentration, the heating of the high-temperature regenerator 4 is performed at the heating position when the concentration reaches the predetermined concentration and the heating position. The heating amount of the regenerator is easily reduced by limiting the heating of the regenerator to the control of the two positions among the control of the three positions, which is repeatedly controlled to the heating position less than the position at every first predetermined time. Thus, it is possible to easily cope with an increase in the concentration of the concentrated liquid.

Further, according to the third aspect of the present invention, when the concentration of the concentrated solution rises to the predetermined concentration, the heating of the regenerator is started from the heating position when the concentration of the concentrated solution reaches the predetermined concentration. Since the concentration of the concentrated liquid is increased to the predetermined concentration, the heating of the regenerator is stopped based on the cold water outlet temperature, and the heating is controlled to one of the three positions of weak heating and strong heating. When the heating is controlled to either weak heating or strong heating, the amount of heating of the absorbent in the regenerator is reduced, so that the concentration of the absorbent is quickly decelerated and the absorption is reduced. The absorption of the refrigerant vapor in the reactor continues, and the concentration of the concentrated liquid returning from the regenerator to the absorber decreases.
As a result, crystallization of the absorbing solution can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a relationship diagram between a cold water outlet temperature and a heating amount maximum value.

FIG. 3 is a relationship diagram between a cold water outlet temperature and a heating position.

FIG. 4 is a schematic configuration diagram of an absorption refrigerator showing a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of heating position control when the concentration of a concentrated liquid reaches a predetermined concentration during strong heating.

FIG. 6 is an explanatory diagram of heating position control when the concentration of the concentrated liquid reaches a predetermined concentration during weak heating.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 2 Absorber 4 High temperature regenerator 6 Low temperature regenerator 9 Low temperature heat exchanger 10 High temperature heat exchanger 20 Refrigerant pump 31 First temperature detector 32 Second temperature detector 33 Controller

Claims (3)

(57) [Claims] 1. An absorption system in which a regenerator, a condenser, an evaporator, an absorber, and the like are connected by piping, and the heating of the regenerator is stopped, weakly heated, and strongly heated based on the cold water outlet temperature of the evaporator. In the control method of the refrigerator, when the cooling water inlet temperature of the absorber is higher than the high temperature set value or lower than the low temperature set value, the maximum heating position of the regenerator is controlled based on the cooling water inlet temperature, and The absorption type wherein heating of the regenerator is stopped based on the cold water outlet temperature regardless of the cooling water inlet temperature until the heating of the regenerator reaches the maximum position, and the heating is controlled at three positions of weak heating and strong heating. Refrigerator control method. 2. An absorption system in which a regenerator, a condenser, an evaporator, an absorber, and the like are connected by piping, and the heating of the regenerator is stopped, weakly heated, and strongly heated based on the cold water outlet temperature of the evaporator. In the control method of the refrigerator, when the concentration of the concentrated solution rises to the predetermined concentration, the heating of the regenerator is performed at predetermined time intervals when the concentration of the concentrated solution reaches the predetermined concentration, A method for controlling an absorption refrigerator, wherein the heating position is controlled to a heating position having a smaller heating amount than a heating position when the concentration is reached. 3. A regenerator, a condenser, an evaporator, an absorber and the like are connected by piping, and the heating of the regenerator is stopped based on the cold water outlet temperature of the evaporator, and the absorption is controlled at three positions of weak heating and strong heating. In the control method of the refrigerator, when the concentrated liquid concentration rises to a predetermined concentration, the heating of the regenerator is controlled to a heating position having a smaller heating amount than the heating position when the concentrated liquid concentration reaches the predetermined concentration for a predetermined time. A method for controlling an absorption refrigerator.