JPH08233392A - Absorption type refrigerating machine - Google Patents

Abstract

PURPOSE: To make stabilization of a cooling water outlet temperature compatible with shortening of a rise time by a method wherein when the cooling water outlet temperature of a vaporizer is higher than a set temperature, proportional, differential, and integral control of a quantity of heating of a regenerator are stopped, and a quantity of heating of the regenerator is increased to a value higher than a quantity of heating obtained through proportional, differential, and integral control. CONSTITUTION: When a cooling water outlet temperature exceeds a limit temperature, a control switch 34 is operated to change-over a change-over switch 37 to a forced controller 36 side and switch opening control of a control valve 29b to control based on an opening signal from an PID computer 35, i.e., from PID control to control executed based on an opening signal for a forced controller 36. This constitution controls a high temperature regenerator 1 to 100% of maximum heating and maximizes capacity of an absorption type refrigerating machine, whereby when a cold water outlet temperature during the starting of operation is high or a load is remarkably increased in a short time, a cold water outlet temperature is lowered in a very short time, and a rise time is eminently shortened, and stabilization of a cold water outlet temperature is compatible with shortening of a rise time during the starting of operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerating machine, and more particularly to an absorption refrigerating machine provided with a control device for controlling the amount of heat of a regenerator in proportion to the cold water outlet temperature.

[0002]

2. Description of the Related Art For example, in Japanese Unexamined Patent Publication No. 2-199509, the heating amount of a regenerator (generator) of an absorption refrigerator is proportional,
In a control device that performs differential and integral control, the load is forcibly changed at the time of test operation after installation of the absorption chiller, and the parameters of proportional control, differential control, and integral control are automatically determined by fuzzy inference based on human experience. A controller for tuning is disclosed.

[0003]

SUMMARY OF THE INVENTION In the above conventional technique,
In order to reduce the cold water outlet temperature from the evaporator to the set temperature in a short time at the start of operation of the absorption chiller and shorten the rise time, generally, proportional control, derivative control and integral control (hereinafter referred to as PID control). Adjust the parameter of to control faster (eg, increase the parameter of proportional control).
Need to be

Further, in order to stabilize the cold water outlet temperature and perform stable control without hunting, it is generally necessary to adjust the parameters of the PID control to make the control slower (for example, to reduce the parameter of the proportional control). is there.

As described above, in the conventional PID control, the shortening of the rise time of the cold water outlet temperature and the stability of the cold water outlet temperature are in conflict with each other, and either one must be sacrificed to some extent.

That is, if the emphasis is placed on shortening the rise time of the cold water outlet temperature, the stability of the cold water outlet temperature becomes poor, and if the importance of stabilizing the cold water outlet temperature is placed, the rise time of the cold water outlet temperature becomes long. To do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention according to claim 1 circulates a refrigerant and an absorption liquid by connecting a regenerator, a condenser, an evaporator, an absorber and the like by piping. In an absorption refrigerator that forms a passage and supplies cold water from the evaporator, a regenerator that compares the temperature detector that detects the cold water outlet temperature from the evaporator with the temperature detected by this temperature detector and the set temperature. If the detected temperature is higher than the set temperature by a predetermined value or more, the proportional, derivative and integral control of the heating amount of the regenerator is stopped, and the heating amount of the regenerator is proportional, derivative and integral. And an absorption refrigerating machine provided with a control device for controlling the amount of heat to be larger than that by the integral control.

Further, the invention of claim 2 is an absorption refrigeration system in which a regenerator, a condenser, an evaporator, an absorber, etc. are connected by piping to form a circulation path for a refrigerant and an absorption liquid, and cold water is supplied from the evaporator. In the machine, the temperature detector that detects the cold water outlet temperature from the evaporator is compared with the temperature detected by this temperature detector and the set temperature to perform proportional, differential and integral control of the heating amount of the regenerator. When the temperature is higher than the upper limit temperature set higher than the set temperature, the proportional, differential and integral control of the heating amount of the regenerator is stopped, and the heating amount of the regenerator is controlled to be larger than the heating amount by the proportional, differential and integral control. In addition, if the detected temperature becomes lower than the upper limit temperature while the heating amount of the regenerator is controlled to a large extent, the absorption refrigeration system is equipped with a control device that controls the heating amount of the regenerator in a proportional, differential and integral manner. Machine. .

The invention according to claim 3 is characterized in that the heating amount of the regenerator is controlled to 100% after the proportional, differential and integral control of the regenerator heating amount is stopped. The above-mentioned absorption refrigerator is provided. .

Further, the invention of claim 4 is an absorption refrigeration system in which 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 absorption liquid, and cold water is supplied from the evaporator. In the machine, the temperature detector that detects the cold water outlet temperature from the evaporator is compared with the temperature detected by this temperature detector and the set temperature to perform proportional, differential and integral control of the heating amount of the regenerator. When the temperature is higher than the set temperature by a specified value or more, the proportional, derivative and integral control of the regenerator heating amount is stopped, the regenerator heating amount is controlled to be larger than before the proportional, derivative and integral control was stopped, and the proportional control is proportional. The present invention provides an absorption refrigerator, which is equipped with a control device that changes a predetermined value in proportion to the band. .

Further, the invention of claim 5 is an absorption refrigeration system in which 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 absorption liquid, and cold water is supplied from the evaporator. In the machine, the temperature detector that detects the cold water outlet temperature from the evaporator is compared with the temperature detected by this temperature detector and the set temperature to perform proportional, differential and integral control of the heating amount of the regenerator. When the temperature is lower than the set temperature by a predetermined value or more, the control device for stopping the proportional, differential and integral control of the regenerator heating amount and controlling the regenerator heating amount to be smaller than the proportional, differential and integral control heating amount is provided. The present invention provides an absorption refrigerating machine. .

Further, the invention of claim 6 is an absorption refrigeration system in which 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 absorption liquid, and cold water is supplied from the evaporator. In the machine, the temperature detector that detects the cold water outlet temperature from the evaporator is compared with the temperature detected by this temperature detector and the set temperature to perform proportional, differential and integral control of the heating amount of the regenerator. When the temperature is lower than the lower limit temperature set lower than the set temperature, the proportional, derivative and integral control of the heating amount of the regenerator is stopped, and the heating amount of the regenerator is controlled to be smaller than the heating amount by the proportional, derivative and integral control. In addition, when the detected temperature becomes higher than the lower limit temperature when the heating amount of the regenerator is controlled to be small, the absorption refrigeration is equipped with a control device that controls the heating amount of the regenerator in a proportional, differential and integral manner. Machine. .

The invention according to claim 7 is characterized in that the heating amount of the regenerator is controlled to a preset minimum heating amount after the proportional, differential and integral control of the heating amount of the regenerator is stopped. An absorption refrigerator according to claim 5 or claim 6 is provided. .

Further, the invention of claim 8 is an absorption refrigeration system in which 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 absorption liquid, and cold water is supplied from the evaporator. In the machine, the temperature detector that detects the cold water outlet temperature from the evaporator is compared with the temperature detected by this temperature detector and the set temperature to perform proportional, differential and integral control of the heating amount of the regenerator. When the temperature is lower than the preset temperature by a predetermined value or more, the proportional, derivative and integral control of the regenerator heating amount is stopped, the regenerator heating amount is controlled to be smaller than the proportional, derivative and integral control heating amount, and the proportional control The present invention provides an absorption refrigerator, which is equipped with a control device that changes a predetermined value in proportion to a proportional band. .

[0015]

According to the invention of claim 1, when the chilled water outlet temperature is higher than the set temperature by a predetermined value or more at the start of operation of the absorption chiller (at start-up) or when the load is significantly increased in a short time. , A control device that receives a signal from the temperature detector operates to stop the PID control of the heating amount of the regenerator,
The heating amount is controlled to be larger than that by the PID control, and the capacity of the absorption refrigerator is further increased. Therefore, even when the cold water outlet temperature at the start of operation is high or when the load increases significantly in a short time, the cold water outlet temperature can be reduced in a short time, and the rise time or the time required for the temperature reduction can be shortened. As a result, it is possible to achieve both the contradictory stabilization of the cold water outlet temperature, the shortening of the start-up time at the start of operation, and the quick response to a sudden increase in load.

Further, according to the invention of claim 2, the chilled water outlet temperature becomes higher than the set upper limit temperature higher than the set temperature due to a large increase of the load in a short time, and the PID control is stopped. When the heating amount of the regenerator is further controlled, the capacity of the absorption chiller increases, and then the chilled water outlet temperature drops sharply and becomes lower than the upper limit temperature, the control device operates and regeneration by PID control is performed. Switching to the heating amount control of the regenerator, hunting near the set temperature of the cold water outlet temperature can be prevented, and the cold water outlet temperature can be stabilized even after the heating amount of the regenerator increases.

According to the third aspect of the present invention, when the chilled water outlet temperature is higher than the set temperature by a predetermined value or more when the absorption refrigerating machine is started (at the start-up) or when the load is significantly increased in a short time. In order to maximize the capacity of the absorption chiller, the controller that receives a signal from the temperature detector operates to control the heating amount of the regenerator from PID control to 100% of the maximum heating amount. Therefore, even when the cold water outlet temperature at the start of operation is high or when the load increases significantly in a short time, the cold water outlet temperature will drop in an extremely short time, and the start-up time or the time required for temperature drop will be greatly shortened. As a result, it is possible to achieve both the contradictory stabilization of the cold water outlet temperature, the shortening of the rising time at the start of operation, and the quick response to a sudden increase in load.

Further, according to the invention of claim 4, the chilled water outlet temperature detected by the temperature detector is compared with the set temperature to perform PID control of the heating amount of the regenerator, and the chilled water outlet temperature is a predetermined value from the set temperature. If it is higher than the above, the PID control is stopped, the heating amount of the regenerator is controlled to be larger than the heating amount by the PID control, and the predetermined value is changed in proportion to the proportional band of the proportional control of the PID control. When the proportional band is set to a large value based on the characteristics of each machine, the predetermined value is also set to a large value and the upper limit temperature becomes high.
The range of control is limited to a narrow range below the upper limit temperature that ignores the setting of the proportional band, that is, the heating amount control of the regenerator that ignores the setting of the proportional band can be avoided, and the setting of the proportional band is considered. It becomes possible to perform more stable operation control of the absorption refrigerator.

Further, according to the invention of claim 5, when the load of the absorption refrigerator is significantly reduced in a short time and the chilled water outlet temperature is lower than the set temperature by a predetermined value or more, the temperature detector The control device that receives a signal from the device operates to stop the PID control of the heating amount of the regenerator, and controls the heating amount to be smaller than the heating amount by the PID control. Even when the temperature significantly decreases in a short time, the cold water outlet temperature can be stopped and raised in a short time.As a result, the conflicting cold water outlet temperature can be stabilized and the cold water outlet temperature can be reduced in a short time when the load suddenly decreases. It is possible to achieve compatibility with both.

Further, according to the invention of claim 6, the regenerator is controlled to be smaller than the heating amount by PID control, the capacity of the absorption refrigerator is lowered, and the chilled water outlet temperature rises sharply to become higher than the lower limit temperature. When it becomes, the control device operates and P
The control switches to the heating amount control of the regenerator by the ID control, hunting near the set temperature of the cold water outlet temperature can be prevented, and the cold water outlet temperature after the minimum heating operation of the regenerator can be stabilized.

Further, according to the invention of claim 7, when the load of the absorption refrigerator is greatly reduced in a short time, and the chilled water outlet temperature is lower than the set temperature by a predetermined value or more, the temperature detector The control device that received the signal from the controller operates to switch the heating amount of the regenerator from the PID control to the minimum heating amount, and the capacity of the absorption chiller becomes the minimum, so the load is greatly reduced in a short time. In such cases, it is possible to stop the cold water outlet temperature in an extremely short time and raise the cold water outlet temperature in an extremely short time.As a result, the contradictory stable cold water outlet temperature and the short time when the load suddenly decreases It is possible to achieve both compatibility with.

Further, according to the invention of claim 8, the chilled water outlet temperature detected by the temperature detector is compared with the set temperature to perform PID control of the heating amount of the regenerator, and the chilled water outlet temperature is a predetermined value from the set temperature. If it is lower than the above, the PID control is stopped, the heating amount of the regenerator is controlled to be smaller than the heating amount by the PID control, and the predetermined value is changed in proportion to the proportional band of the proportional control of the PID control. Therefore, when the proportional band is set to a large value based on the characteristics of each device of the absorption chiller, the predetermined value is also set to a large value and the lower limit temperature becomes low,
The range of PID control is limited to a narrow range above the lower limit temperature that ignores the setting of the proportional band, that is, it is possible to avoid the heating amount control of the regenerator that ignores the setting of the proportional band, and consider the setting of the proportional band. Therefore, it becomes possible to perform more stable operation control of the absorption refrigerator.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment relating to the inventions of claim 1, claim 2, claim 3, claim 5, claim 6 and claim 7 of the present invention will be described below in detail with reference to the drawings.

Reference numeral A shown in FIG. 1 denotes a double-effect absorption refrigerator (hereinafter referred to as an absorption refrigerator), which has, for example, water (H 2 O) as a refrigerant and lithium bromide (LiB) as an absorption liquid (solution).
r) The solution was used.

In FIG. 1, 1 is a high temperature regenerator using a burner B whose fuel is gas, for example, as a heat source, 2 is a low temperature regenerator,
3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a condenser heat exchanger, 7 is an evaporator heat exchanger, 8 is an absorber heat exchanger, 9 is a low temperature regenerator 2 and a condenser 3. The stored upper body 10 is a lower body containing the evaporator 4 and the absorber 5.

The respective equipments are provided with absorbing liquid pipes 11 to 15
And refrigerant pipes 16 to 18 for pipe connection. Further, 11a is a low temperature heat exchanger, 11b is a high temperature heat exchanger, 20 is an absorption liquid pump, 21 is a refrigerant liquid circulation pipe, 22
Is a refrigerant circulation pump. Reference numeral 23 denotes an absorbent bypass pipe connecting the absorber 5 to the absorber 5 and an opening / closing valve 24, and 25 denotes a refrigerant bypass pipe connecting the absorber pipe 16 to the absorber 5 and an opening / closing valve 26. is there.

Reference numeral 27 is a cooling water pipe, in which an absorber heat exchanger 8 and a condenser heat exchanger 6 are provided. 28
Is a hot and cold water pipe, and an evaporator heat exchanger 7 is provided on the way.

Further, 29 is a fuel supply pipe connected to the burner B, and 29b is a fuel control valve provided in the middle of the fuel supply pipe 29.

Reference numeral 30 denotes a cold / hot water outlet temperature (hereinafter referred to as cold / warm water temperature) detector (hereinafter referred to as temperature detector) provided on the evaporator outlet side of the cold / hot water pipe 28. Three
Reference numeral 1 is a control device that inputs a signal from the temperature detector 30 and outputs an opening signal to the fuel control valve 29b in accordance with the temperature of the cold water. The control device 31 includes a hot / cold water outlet setting device 32 and a PI.
D constant setter 33, control switch 34, PID calculator 35
And a compulsory controller 36, and a changeover switch 37 for switching the contact piece according to a signal from the control changer 34.

The cold / hot water outlet temperature setter 32 sets the cold water outlet temperature to, for example, 7 ° C. and the hot water outlet temperature to, for example, 42 ° C. Further, the PID constant setter 33 presets each constant or parameter of the PID control, for example, by balancing the speed and stability of the control.

The control switch 34 has a temperature detected by the temperature detector 30 which is equal to or higher than the upper limit temperature 8 ° C. obtained by adding a predetermined value 1 (for example, 1 ° C.) to the cold water preset temperature set by the cold / hot water outlet temperature setter 32, or the cold water. It is determined whether a lower limit temperature of 6 ° C or less is obtained by subtracting a predetermined value 2 (for example, 1 ° C) from the set temperature, and the contact piece of the changeover switch 37 is forcibly controlled when the detected temperature is equal to or higher than the upper limit temperature or equal to or lower than the lower limit temperature. When the detected temperature is lower than the upper limit temperature and higher than the lower limit temperature, the contact piece of the changeover switch 37 is switched to the PID calculator 35 side.

The PID calculator 35 is a PID constant setter 33.
The PID calculation is performed according to the detected temperature based on the constant set in, and the opening signal is output. The forced controller 36 outputs a fully open signal (100%) or a preset minimum opening (for example, 30%) signal according to the detected temperature. Then, as shown in FIG. 2, when the temperature detected by the temperature detector 30, that is, the chilled water outlet temperature is lower than or equal to the lower limit temperature (chilled water set temperature-predetermined value 2), as shown in FIG. The opening degree of the control valve 29b is controlled to the minimum opening degree, and the high temperature regenerator 1 is heated to the minimum. Further, when the cold water outlet temperature is equal to or higher than the upper limit temperature (cold water set temperature + predetermined value 1), the opening degree of the control valve 29b is controlled to 100% and the high temperature regenerator 1 is heated to 100%. Further, when the detected temperature is higher than the lower limit temperature and lower than the upper limit temperature, the control valve 29b
The opening degree of is controlled to the opening degree calculated by the PID calculator 35.

Absorption refrigerator A constructed as described above
During operation of the cold water supply, the on-off valves 24 and 26 are closed,
Further, the control device 31 outputs an opening signal to the control valve 29b according to the temperature detected by the temperature detector 30, and the burner B burns. Due to the combustion of the burner B, the absorbent having a low concentration (hereinafter referred to as the rare absorbent) in the high temperature regenerator 1 is heated, the refrigerant vapor is separated from the rare absorbent, and the intermediate concentration of the absorbent (hereinafter referred to as the intermediate absorbent). ) Flows to the low temperature regenerator 2 via the high temperature heat exchanger 11b. In the low temperature regenerator 2, the intermediate absorbing liquid is heated by the refrigerant vapor from the high temperature regenerator 1, the refrigerant is further separated from the intermediate absorbing liquid, and the refrigerant vapor flows to the condenser 3. The absorption liquid (hereinafter, referred to as a concentrated absorption liquid) having a higher concentration due to the separation of the refrigerant flows to the absorber 5 through the low temperature heat exchanger 11a and is scattered.

The refrigerant condensed in the low temperature regenerator 2 and flown to the condenser 3 and the refrigerant condensed in the low temperature regenerator 2 flow to the evaporator 4 via the refrigerant pipe 18. In the evaporator 4, the refrigerant liquid is sprayed to the evaporator heat exchanger 7 by the operation of the refrigerant circulation pump 22, and heat is taken from the cold water flowing in the evaporator heat exchanger 7 when it is evaporated. Then, the cold water whose temperature has dropped is supplied to the load. In addition, the evaporated refrigerant flows into the absorber 5 and is absorbed by the concentrated absorbent that has been sprayed. The rare absorption liquid that has become thin due to the absorption of the refrigerant is driven by the absorption liquid pump 20 to operate the low temperature heat exchanger 1.
It is sent to the high temperature regenerator 1 via 1a and the high temperature heat exchanger 11b.

During operation of the absorption refrigerator as described above, the controller 31 inputs a signal from the temperature detector 30. Then, the PID calculator 34 inputs the cold water outlet temperature detected by the temperature detector 30, performs PID calculation, and outputs an opening signal. When the chilled water outlet temperature is higher than the lower limit temperature and lower than the upper limit temperature, the changeover switch 37 is switched to the PID calculator 35 side by a signal from the control changer 34. Therefore, the opening signal output from the PID calculator 34 is directly sent to the control valve 29b, and the control valve 29b
Is controlled to the opening determined by the PID calculator 35, and the PID control of the heating amount is performed.

At the time of starting the operation of the absorption refrigerator, that is, at the time of start-up, the temperature and pressure of each device of the absorption refrigerator do not rise and the refrigerating capacity is small, so the cold water outlet temperature is higher than the upper limit temperature. Therefore, the control switch 34 switches the changeover switch 37 to the forced controller 36 side. Therefore, the control of the opening degree of the control valve 29b by the calculation of the PID calculator 35, that is, the PID control of the heating amount of the high temperature regenerator 1 is stopped. Further, the forced controller 36 inputs the cold water outlet temperature detected by the temperature detector 30 and has a maximum opening larger than the opening calculated by the PID calculator 35 before the PID control is stopped.
A 00% opening signal is output, and this opening signal is sent to the control valve 29b via the changeover switch 37. The control valve 29b to which the opening signal is input is fully opened, the burner B is combusted 100%, and the heating amount of the high temperature regenerator 1 becomes larger than the heating amount under the control of the PID calculator 35 and becomes maximum.

The chilled water outlet temperature is between the lower limit temperature and the upper limit temperature, and the PID calculator 3 is based on the chilled water outlet temperature.
When the opening degree signal of the control valve 29b is controlled by the opening degree signal output by the operation of No. 5, even when the load rapidly increases and the chilled water outlet temperature becomes equal to or higher than the upper limit temperature, Similar to the control, the control switch 34 is provided with a changeover switch 37.
To the forced controller 36 side, and the PID control is stopped. The forced controller 36 also inputs the cold water outlet temperature,
A 00% opening signal is output, and this opening signal is sent to the control valve 29b via the changeover switch 37. The control valve 29b to which the opening signal is input is fully opened, the burner B is combusted 100%, and the heating amount of the high temperature regenerator 1 is maximized.

Therefore, the refrigerant generating capacity of the high temperature regenerator 1 and the refrigerating capacity of the absorption refrigerator are controlled to the maximum, and the chilled water outlet temperature is rapidly lowered. Then, when the chilled water outlet temperature becomes lower than the upper limit temperature, the control switching device 34 operates to output a switching signal, and the switching switch 37 is operated from the compulsory controller 36 side to P
It switches to the ID calculator 35 side. Therefore, the opening signal output from the PID calculator 35 is sent to the control valve 29b via the changeover switch 37. The PID calculator 35 controls the control valve 2 based on the cold water outlet temperature, the cold water set temperature, and the PID constant.
The opening of 9b is calculated and an opening signal is output. Then, the opening degree of the control valve 29b is controlled to the opening degree calculated by the PID calculator 35, and the chilled water outlet temperature is controlled to almost the chilled water set temperature.

As described above, the opening degree of the control valve 29b is PID.
When the opening degree calculated by the computing unit 35 is controlled, the cold water is supplied from the absorption refrigerator and the cooling operation is performed, for example, when the office is closed and the load is sharply reduced. The temperature drops sharply. Then, the opening signal of the PID calculator 35 reduces the opening of the control valve 29b, and the capacity of the high temperature regenerator 1 is decreased. However,
When the chilled water outlet temperature further decreases due to the sudden decrease in load to reach the lower limit temperature of 6 ° C. or less, the control switching device 34 operates and outputs a switching signal, and the switching switch 37 causes the PID calculator 35 side to forcibly control the controller 37. It switches to the 36 side and PID control stops. Further, the compulsory controller 36 outputs a signal of the minimum opening smaller than the opening when the PID control is stopped when the chilled water outlet temperature is equal to or lower than the lower limit temperature, and the opening signal is the control valve 29.
sent to b.

Therefore, the control valve 29b has a minimum opening degree of 30.
%, The burner B attains the minimum combustion smaller than the combustion amount when the PID control is stopped, and the heating amount of the high temperature regenerator 1 is forcibly controlled to the minimum. Then, the refrigerant vapor generation amount in the high temperature regenerator 1 sharply decreases, and the refrigerating capacity of the absorption chiller also sharply decreases and is controlled to the minimum.

When the refrigerating capacity becomes the minimum, the cold water outlet temperature stops decreasing and the cold water outlet temperature rapidly rises according to the cooling load. Then, when the chilled water outlet temperature becomes higher than the lower limit temperature, the control switching device 34 operates to output a switching signal, and the switching switch 37 is operated from the side of the compulsory controller 36 to the PID calculator 3.
Switch to 5 side. Therefore, the opening signal output from the PID calculator 35 is transmitted via the changeover switch 37 to the control valve 29b.
Sent to. Then, the opening degree of the control valve 29b is controlled to the opening degree calculated by the PID calculator 35, and the chilled water outlet temperature is controlled to almost the chilled water set temperature.

Thereafter, the control device 31 operates based on the cold water outlet temperature detected by the temperature detector 30, and when the cold water outlet temperature is equal to or higher than the upper limit temperature, the control switch 34 operates to perform the forced control, as in the above description. The high temperature regenerator 1 is controlled to 100% of the maximum heating based on the opening signal from the cooler 36, and the capacity of the absorption refrigerator is controlled to the maximum. When the chilled water outlet temperature is lower than or equal to the lower limit temperature, the control switch 34 operates, the high temperature regenerator 1 is controlled to the minimum heating based on the opening signal from the compulsory controller 36, and the capacity of the absorption refrigerator is reduced. Controlled to a minimum.

Further, when the chilled water outlet temperature is between the upper limit temperature and the lower limit temperature, the control changeover device 34 changes the changeover switch 37.
To the PID calculator 35 side. Therefore, the opening degree of the control valve 29b is controlled according to the opening degree signal from the PID calculator 35, and the PID control of the heating amount of the high temperature regenerator 1 is performed.

According to the first embodiment, when the chilled water outlet temperature is equal to or higher than the upper limit temperature at the time of starting the operation of the absorption chiller or when the load is significantly increased in a short time,
The control switch 34 operates to switch the changeover switch 37 to the side of the forced controller 36, and the opening degree control of the control valve 29b becomes PI.
Control based on the opening signal from the D calculator 35, that is, PID
The control immediately switches to the control based on the opening signal of the forced controller 36, the high temperature regenerator 1 is controlled to 100% of the maximum heating, and the capacity of the absorption chiller is maximized. Even when the temperature is high or the load increases significantly in a short time, the cold water outlet temperature can be lowered in a very short time, and the rise time can be greatly shortened. As a result, the contradictory cold water outlet temperature can be reduced. It is possible to achieve both the stability of the above and the shortening of the start-up time at the start of operation and the quick response to the sudden increase of the load.

In addition, the high temperature regenerator 1 has a maximum heating of 100.
%, The capacity of the absorption chiller becomes maximum, and the chilled water outlet temperature sharply drops and becomes lower than the upper limit temperature, the control based on the opening signal from the forced controller 36 causes P
Switching to control of the control valve 29b by the opening signal from the ID calculator 35, preventing hunting near the cold water set temperature of the cold water outlet temperature, and stabilizing the cold water outlet temperature after 100% heating operation of the high temperature regenerator 1. can do.

When the chilled water outlet temperature becomes lower than or equal to the lower limit temperature, for example, when the load suddenly and significantly decreases, the control changeover device 34 operates to change over the changeover switch 37 to the compulsory control device 36 side. The opening degree control of the control valve 29b is immediately switched from the control based on the opening degree signal from the PID calculator 35 to the control based on the opening degree signal from the compulsory controller 36, and the high temperature regenerator 1 is controlled to minimum heating and absorption. Since the capacity of the refrigerator is minimized, the cold water outlet temperature can be raised in a short time, and the time required to raise the cold water outlet temperature can be greatly shortened. In addition, it is possible to achieve both a quick response to a sudden load decrease.

Further, at the start of operation of the absorption chiller or when the load changes significantly, the controller switching unit 34 operates to control 100% heating or minimum heating of the high temperature regenerator 1. , PID setting for PID control does not need to be a set value that takes into consideration the start of operation or when the load changes significantly. “Cold water set temperature-predetermined value 2” to “cold water set value + predetermined value” Since it suffices to consider the load fluctuation in the range of "1", that is, the range of 6 ° C to 8 ° C, the PID setting can be easily performed, and the cold water outlet temperature can be further stabilized.

In the above embodiment, when the chilled water outlet temperature is equal to or higher than the upper limit temperature, the PID control of the heating amount based on the calculation of the PID calculator 35 is stopped, and based on the opening signal from the compulsory controller 36, The heating amount of the high temperature regenerator 1 was controlled to 100% of the maximum, but when the PID control was stopped, PI
An opening that is larger than the control valve opening by D control, for example, an opening based on PID control, plus a predetermined opening (for example, 20%) (maximum opening 100% is the upper limit), or a preset large predetermined opening ( For example, when controlling to 95% which is close to 100%), the control valve 2 is controlled as described in the above embodiment.
Although it is slightly inferior to the action and effect when the opening degree of 9b is controlled to 100%, almost the same action and effect can be obtained.

In the above embodiment, when the chilled water outlet temperature is below the lower limit temperature, the PID control of the heating amount based on the calculation by the PID calculator 35 is stopped, and based on the opening signal from the forced controller 36, Although the heating amount of the high temperature regenerator 1 was controlled to the minimum of 30%, when the PID control is stopped, it is smaller than the control valve opening by the PID control, for example, a predetermined opening (for example, 20%) is subtracted from the opening based on the PID control. Even when the control valve is controlled to a predetermined opening (minimum opening 30% is the lower limit) or a small preset opening (35% close to 30%, for example), the control valve 29b is operated as described in the above embodiment. Although it is slightly inferior to the operation and effect when the opening is controlled to 30% of the minimum opening, almost the same operation and effect can be obtained.

The second embodiment of the inventions of claims 4 and 8 will be described below.

The second embodiment is the same as the first embodiment except for the operation of the control switch 34.
Detailed description thereof will be omitted, and description will be made in the same manner as in the first embodiment based on FIGS. 1 and 2.

The control switch 34 is based on the value of the proportional band (P), which is the proportional term by the differential control from the PID calculator 35, and the predetermined value 1 which is the allowable value higher than the set cold water temperature and the value lower than the set cold water temperature. The predetermined value of 2, which is the allowable value, is adjusted.

That is, the predetermined value 1 changes in proportion to the value of the proportional band (P), and for example, the predetermined value 1 = P / 2 is determined.

At this time, when P = 2, the predetermined value 1 = 1 as in the first embodiment. If the cold water set temperature is set to 7 ° C., the control switch 34
Switches 3 when the cold water outlet temperature is lower than 8 ° C.
7 is switched to the PID calculator 35 side, and the cold water outlet temperature is 8
When the temperature is equal to or higher than ° C, the changeover switch 37 is changed over to the compulsory controller 36 side.

The predetermined value 2 also changes in proportion to the value of the proportional band (P), and for example, the predetermined value 2 = P / 2 is determined.

At this time, when P = 2, the predetermined value 2 = 1 as in the first embodiment. If the cold water set temperature is set to 7 ° C., the control switch 34
Switch 3 when the cold water outlet temperature is higher than 6 ° C.
7 is switched to the PID calculator 35 side, and the chilled water outlet temperature is 6
When the temperature is equal to or lower than ° C, the changeover switch 37 is changed over to the forced controller 36 side.

A predetermined value 1 according to the change of the proportional band (P)
And the predetermined value 2 changes, and becomes larger as the proportional band (P) becomes larger, and becomes smaller as the proportional band (P) becomes smaller.

Generally, the PID control is a slow control when the proportional band (P) is large, and a fast control when the proportional band (P) is small.

Although the proportional band (P) is set to a large value based on the characteristics of each device of the absorption refrigerator, the predetermined value 1 and the predetermined value 2 are set small and the upper limit temperature and the lower limit temperature are set to the cold water set temperature. When fixed in the vicinity, the proportional band (P) is ignored in the range above the upper limit temperature and below the lower limit temperature. Therefore, the range of PID control is limited to a narrow range between the upper limit temperature and the lower limit temperature, and there is no point in setting the proportional band (P) large.

Therefore, according to the second embodiment, the setting of the proportional band (P) is ignored as described above by determining the predetermined value 1 and the predetermined value 2 according to the proportional band (P). The heating amount control of the high temperature regenerator 1 can be avoided, and more stable operation control of the absorption chiller can be performed in consideration of the setting of the proportional band (P).

The invention of the present application is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention of the present application.

For example, in the above embodiment, the double-effect absorption refrigerator was explained in FIG. 1. However, even when the present invention is applied to the single-effect absorption refrigerator, the same operation as in each of the above embodiments is performed. The effect can be obtained.

[0063]

The present invention is an absorption chiller configured as described above. According to the invention of claim 1, when the absorption chiller is started to operate or the load is greatly increased in a short time. When the chilled water outlet temperature is higher than the set temperature by a predetermined value or more, the control device that inputs a signal from the temperature detector operates to stop the PID control of the heating amount of the regenerator, and the heating amount of the regenerator is stopped. Is controlled to be larger than the heating amount by PID control,
Since the capacity of the absorption chiller further increases, the chilled water outlet temperature is reduced in a short time and the startup time is shortened even when the chilled water outlet temperature at the start of operation is high or the load increases significantly in a short time. As a result of this,
It is possible to achieve both the contradictory stabilization of the cold water outlet temperature, the shortening of the start-up time at the start of operation, and the quick response to a sudden load increase.

According to the second aspect of the invention, the chilled water outlet temperature is higher than the set temperature and is equal to or higher than the set upper limit temperature, and the heating amount of the regenerator is controlled to be larger than that during the PID control. When the capacity further increases and then the chilled water outlet temperature drops sharply and becomes lower than the upper limit temperature, the control device operates and switches to the heating amount control of the regenerator by the PID control to set the chilled water outlet temperature set temperature. It is possible to prevent hunting in the vicinity and stabilize the cold water outlet temperature after 100% heating operation of the regenerator.

According to the third aspect of the present invention, when the chilled water outlet temperature is higher than the set temperature by a predetermined value or more, for example, at the start of operation of the absorption chiller or when the load is significantly increased in a short time. Is operated by a controller that receives a signal from the temperature detector to control the heating amount of the regenerator to 100% of the maximum heating amount, and the capacity of the absorption chiller becomes maximum, so the cold water outlet at the start of operation Even when the temperature is high or the load increases significantly in a short time, the cold water outlet temperature can be lowered in a very short time, and the rise time can be greatly shortened. As a result, the contradictory cold water outlet temperature can be reduced. It is possible to achieve both the stability of the above and the shortening of the start-up time at the start of operation and the quick response to the sudden increase of the load.

According to the invention of claim 4, the cold water outlet temperature detected by the temperature detector is compared with the set temperature to perform PID control of the heating amount of the regenerator, and the cold water outlet temperature is set to a predetermined value from the set temperature. If it is higher than the above, the PID control is stopped, the heating amount of the regenerator is controlled to be higher than the heating amount by the PID control, and the predetermined value is changed in proportion to the proportional band of the proportional control of the PID control. When the proportional band is set to a large value based on the characteristics of each device of the machine, the predetermined value is set to a large value accordingly and the upper limit temperature becomes high, and the PID control range is narrower than the upper limit temperature ignoring the setting of the proportional band. That is, the heating amount control of the regenerator ignoring the setting of the proportional band can be avoided, and more stable operation control of the absorption chiller can be performed in consideration of the setting of the proportional band.

According to the fifth aspect of the present invention, when the load of the absorption refrigerator is significantly reduced in a short time and the chilled water outlet temperature is lower than the set temperature by a predetermined value or more, the temperature detector The control device that received the signal from the device operates to stop the PID control of the heating amount of the regenerator,
Since it is controlled to be smaller than the heating amount by control, it is possible to stop and raise the chilled water outlet temperature in a short time even when the load is greatly reduced in a short time, and as a result, the contradictory chilled water outlet temperature can be increased. It is possible to achieve both the stability and the quick response to a sudden load decrease.

According to the invention of claim 6, the regenerator is controlled to a heating amount smaller than the heating amount by the PID control,
When the capacity of the absorption chiller further decreases and the chilled water outlet temperature rises sharply and becomes lower than the lower limit temperature, the control device operates to switch to the heating amount control of the regenerator by PID control, and the chilled water outlet temperature It is possible to prevent hunting near the set temperature and to stabilize the cold water outlet temperature after 100% heating operation of the regenerator.

Further, according to the invention of claim 7, when the load of the absorption refrigerator is greatly reduced in a short time and the chilled water outlet temperature is lower than the set temperature by a predetermined value or more, the temperature detector The control device that receives the signal from the controller operates to control the heating amount of the regenerator from PID control to the minimum heating amount, and the capacity of the absorption refrigerator is minimized. In addition, the cold water outlet temperature can be stopped in a very short time and the cold water outlet temperature can be raised in a short time. As a result, the conflicting cold water outlet temperature can be stabilized and the load can be reduced in a short time. Can be compatible with both.

According to the invention of claim 8, the chilled water outlet temperature detected by the temperature detector is compared with the set temperature to perform PID control of the heating amount of the regenerator, and the chilled water outlet temperature is set to a predetermined value from the set temperature. If it is lower than the above, the PID control is stopped, the heating amount of the regenerator is controlled to be smaller than the heating amount by the PID control, and the predetermined value is changed in proportion to the proportional band of the proportional control of the PID control. When the proportional band is set to a large value based on the characteristics of each machine, the predetermined value is also set to a large value and the lower limit temperature is lowered, and the PID control range is a narrow range above the lower limit temperature ignoring the setting of the proportional band. That is, the heating amount control of the regenerator which ignores the setting of the proportional band can be avoided, and the setting of the proportional band is considered.
More stable operation control of the absorption refrigerator can be performed.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a relationship between a chilled water outlet temperature and heating amount control of a regenerator.

[Explanation of symbols]

 A absorption refrigerator 1 high temperature regenerator 2 low temperature regenerator 3 condenser 4 evaporator 5 absorber B burner 29b control valve 30 temperature detector 31 controller

Claims (8)

[Claims] 1. An absorption refrigerator in which a regenerator, a condenser, an evaporator, an absorber, etc. are connected by piping to form a circulation path for a refrigerant and an absorption liquid, and cold water is supplied from the evaporator. A temperature detector that detects the cold water outlet temperature is compared with the detected temperature of this temperature detector and the set temperature to proportionally, differentially and integral control the heating amount of the regenerator, and the detected temperature is higher than the set temperature by a predetermined value or more. In this case, the absorption formula is characterized by including a control device for stopping the proportional, differential and integral control of the heating amount of the regenerator and controlling the heating amount of the regenerator to be larger than the heating amount by the proportional, differential and integral control. refrigerator. 2. An absorption refrigerating machine for supplying cold water from an evaporator by connecting a regenerator, a condenser, an evaporator, an absorber and the like by piping to form a circulation path for a refrigerant and an absorbing liquid, A temperature detector that detects the chilled water outlet temperature is compared with the detected temperature of this temperature detector and the set temperature to control the heating amount of the regenerator proportionally, differentially and integrally, and the detected temperature is set higher than the set temperature. When the temperature is higher than the upper limit temperature, the proportional, differential and integral control of the heating amount of the regenerator is stopped, the heating amount of the regenerator is controlled to be larger than the heating amount by the proportional, differential and integral control, and the heating amount of the regenerator is changed. An absorption chiller comprising a control device for proportional, differential and integral control of the heating amount of the regenerator when the detected temperature becomes lower than the upper limit temperature during large control. 3. The absorption refrigerator according to claim 1, wherein the heating amount of the regenerator is controlled to 100% after the proportional, differential and integral control of the heating amount of the regenerator is stopped. 4. An absorption refrigerating machine for supplying chilled water from an evaporator by connecting a regenerator, a condenser, an evaporator, an absorber and the like by piping to form a circulation path for a refrigerant and an absorbing liquid. A temperature detector that detects the cold water outlet temperature is compared with the detected temperature of this temperature detector and the set temperature to proportionally, differentially and integral control the heating amount of the regenerator, and the detected temperature is higher than the set temperature by a predetermined value or more. In this case, the proportional, derivative, and integral control of the regenerator heating amount is stopped, the regenerator heating amount is controlled to be larger than the heating amount by the proportional, derivative, and integral control, and the proportional amount is proportional to the proportional band of the proportional control. An absorption refrigerator comprising a control device for changing a value. 5. An absorption refrigerating machine for supplying chilled water from an evaporator by connecting a regenerator, a condenser, an evaporator, an absorber and the like by piping to form a circulation path for a refrigerant and an absorbing liquid. A temperature detector that detects the chilled water outlet temperature is compared with the detected temperature of this temperature detector and the set temperature to proportionally, differentially and integral control the heating amount of the regenerator, and the detected temperature is lower than the set temperature by a specified value or more. In the case of absorption refrigeration, the controller controls the proportional, differential and integral control of the heating amount of the regenerator and controls the heating amount of the regenerator to be smaller than the heating amount by the proportional, differential and integral control. Machine. 6. In an absorption refrigerating machine for supplying cold water from the evaporator by connecting a regenerator, a condenser, an evaporator, an absorber and the like by piping to form a circulation path for a refrigerant and an absorbing liquid, A temperature detector that detects the chilled water outlet temperature is compared with the detected temperature of this temperature detector and the set temperature to proportionally, differentially and integral control the heating amount of the regenerator, and the detected temperature is set lower than the set temperature. When the temperature is lower than the lower limit temperature, the proportional, differential and integral control of the heating amount of the regenerator is stopped, the heating amount of the regenerator is controlled to be smaller than the heating amount by the proportional, differential and integral control, and the heating amount of the regenerator is reduced. An absorption chiller comprising a control device for proportional, differential and integral control of the heating amount of the regenerator when the detected temperature becomes higher than the lower limit temperature when controlled to be small. 7. The heating amount of the regenerator is controlled to a preset minimum heating amount after the proportional, differential and integral control of the heating amount of the regenerator is stopped. Absorption refrigerator. 8. An absorption refrigerating machine for supplying chilled water from an evaporator by connecting a regenerator, a condenser, an evaporator, an absorber and the like by piping to form a circulation path for a refrigerant and an absorbing liquid. A temperature detector that detects the chilled water outlet temperature is compared with the detected temperature of this temperature detector and the set temperature to proportionally, differentially and integral control the heating amount of the regenerator, and the detected temperature is lower than the set temperature by a specified value or more. In this case, the proportional, derivative, and integral control of the heating amount of the regenerator is stopped, the heating amount of the regenerator is controlled to be smaller than the heating amount by the proportional, differential, and integral control, and the proportional amount is proportional to the proportional band of the proportional control. An absorption refrigerator comprising a control device for changing a value.