JPH094938A - Heat input controlling method for absorption deep freezer - Google Patents

Abstract

PURPOSE: To prevent the repetition of an abrupt state change by continuing the limiting operation of the maximum heating amount until a predetermined time is elapsed even if resetting conditions are satisfied when the maximum heating amount of a heater is limited depending on the input temperature of cooling water becoming higher or lower than a predetermined value. CONSTITUTION: A controller 34 limits the maximum opening of a fuel control valve 21 to limit the heating amount of a high-temperature regenerator 1 when the cooling water inlet temperature detected by a temperature sensor 32 becomes higher than the first high-temperature set value or lower than the first low- temperature set value. Even if it is slightly lower than the first high-temperature set value or becomes higher than the second low temperature set value slightly higher than the first low-temperature set value and much higher than the second high-temperature set value, the maximum opening of the valve 21 is continuously limited to 50% until a predetermined time is elapsed. Thus, the repetition of an abrupt state change can be prevented.

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 method for controlling a heating amount of a combustion device installed in a regenerator.

[0002]

For example, in Japanese Utility Model Publication No. 62-6449, the heating amount of the regenerator due to the cold water outlet temperature of the evaporator is compensated by the inlet temperature of the cooling water supplied to the absorber so that the cooling water temperature is 32 ° C. There is disclosed a control device for an absorption refrigerating machine that adjusts the opening of a fuel control valve by raising the set value of the cold water outlet temperature as the temperature decreases from 0 to 20 ° C.

However, in the above-mentioned prior art, when the cooling water inlet temperature becomes high, the amount of heating in the regenerator increases as the cooling water load increases, and the refrigerant regenerating temperature and regenerating pressure increase, so that the absorption refrigerator. There was a risk of a safety stop.

When the temperature of the outside air is lowered and the temperature of the cooling water inlet is significantly lowered, the temperature of the concentrated liquid which is sprayed by the absorber and exchanges heat with the cooling water is lowered to the crystal temperature. However, there is a problem that crystals may be generated.

Therefore, a control method for limiting the maximum heating amount according to the cooling water temperature has been proposed. However, the method of reducing the heating amount by the inlet temperature of the cooling water reduces the temperature and pressure in the target regenerator or the concentration of the concentrated liquid, thereby eliminating the above inconvenience, but at the same time, the amount of heat released to the cooling water is also increased. Decrease, leading to a decrease in cooling water temperature. Therefore,
It returns from the heating amount control area and returns to the original heating amount.
Since the operation is performed in the direction in which the cooling water temperature rises, the state in which the heating state changes in a short cycle is repeatedly performed.

[0006]

Therefore, the solution level in the regenerator fluctuates vertically due to a sudden change in the heating amount, and the absorption liquid pump is frequently started / stopped. , A hammer noise is generated in a heat exchanger, etc., it may crystallize depending on the flow of the absorbing liquid. The heating device and the absorbing liquid pump start and stop repeatedly in a short cycle, which is disadvantageous in terms of durability. There were problems such as, and the solution of these problems was an issue.

[0007]

In order to solve the above-mentioned problems of the prior art, the present invention heats a heating device installed in a regenerator that constitutes a refrigeration cycle by connecting a pipe to an absorber, a condenser, an evaporator and the like. The amount is controlled based on the temperature of the cold water taken out from the evaporator, and the maximum heating amount of the heating device is
Limit when the inflow temperature of the cooling water supplied to the absorber / condenser becomes higher than the first high temperature set value or becomes lower than the first low temperature set value. Low When the temperature is lower than the second high temperature set value that is higher than the first low temperature set value, or is higher than the second low temperature set value that is higher than the first low temperature set value and lower than the second high temperature set value. In the heat input control method for an absorption refrigerating machine that returns to the original state, the inflow temperature of the cooling water becomes higher than the first high temperature set value or lower than the first low temperature set value, and the maximum of the heating device is increased. When the heating amount is limited, even if the return condition is satisfied, the heat input control method for the absorption chiller of the first configuration that continues the limiting operation of the maximum heating amount at least until a predetermined time elapses,

In the heat input control method for an absorption refrigerating machine of the first construction, the second construction is such that the maximum heating quantity is restored after a predetermined time has elapsed and the maximum heating quantity restoration condition is satisfied. And a heat input control method for the absorption refrigerator.

Further, the heating amount of the heating device installed in the regenerator which is connected to the absorber, condenser, evaporator, etc. by piping is controlled based on the temperature of the cold water extracted from the evaporator, and Absorption refrigeration for limiting the maximum heating amount of the heating device based on the cooling water inflow temperature when the inflow temperature of the cooling water supplied to the absorber / condenser is higher than the high temperature set value or lower than the low temperature set value. In the heat input control method for a machine, when the inflow temperature of the cooling water is higher than the high temperature set value or lower than the low temperature set value to limit the maximum heating amount of the heating device, at least until a predetermined time elapses. A heat input control method for the absorption chiller having a third configuration, which continues the limited operation of the maximum heating amount;

In the heat input control method for the absorption chiller of the third configuration, when the cooling water inflow temperature returns between the high temperature set value and the low temperature set value and a predetermined time elapses, the maximum heating amount of the heating device is reached. And a heat input control method for an absorption refrigerator having a fourth configuration, which is configured to return the above.

[0011]

[Function] When the temperature of the cooling water supplied to the absorber / condenser rises or falls beyond the design range and the maximum heating amount of the heating device installed in the regenerator is once limited, this maximum heating Since the limited amount operation is continued until a predetermined time elapses, repeated rapid state changes are prevented. For this reason, the next change occurs after the internal state of the aircraft is once stabilized, so that it is possible to prevent the occurrence of troubles that are difficult to predict.

In particular, on the solution surface in the regenerator, the regeneration temperature is once lowered, so that the fluctuation of the liquid surface due to the change of the void ratio is reduced, and the frequent start / stop of the absorbing liquid pump is eliminated. For this reason, the durability of the absorption pump together with the heating device is improved.

Further, since frequent start / stop of the absorbent pump is eliminated, generation of hammer noise in the heat exchanger is prevented.

Further, since the maximum heating amount of the heating device is limited to limit the heating amount in the regenerator, the concentration of the absorbing liquid flowing out from the high temperature regenerator is lowered and crystallization is prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in more detail with reference to the drawings. The one illustrated in FIG. 1 is a dual-effect absorption refrigerator, which uses water (H ₂ O) as a refrigerant and lithium bromide (LiBr) aqueous solution as an absorbent (absorption liquid).

In FIG. 1, 1 is a high temperature regenerator equipped with a gas burner 1B, 2 is a low temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low temperature heat exchanger, and 7 is high temperature heat. Exchanger, 8 to 12 are absorption liquid piping, 15 is absorption liquid pump, 16
18 is a refrigerant pipe, 19 is a refrigerant pump, 20 is a gas pipe connected to the gas burner 1B, 21 is a fuel control valve provided as a device for controlling the heating amount by adjusting the flow rate of gas supplied as fuel, and 22 is a cold water pipe. (Load piping), each of which is connected by piping as shown in FIG.

Further, 25 is a cooling water pipe, and an absorber heat exchanger 26 and a condenser heat exchanger 27 are provided in the middle of the cooling water pipe 25. Further, 28 is a cooling tower, 30
Is a cooling water pump, and a cooling circuit is configured by connecting the cooling tower 28 and the cooling water pump 30 to the cooling water pipe 25.

Further, 31 is the evaporator 4 of the cold water pipe 22.
A temperature detecting means (hereinafter referred to as a first temperature sensor) 32 provided on the outlet side to detect the outlet temperature T1 of the cold water, and 32 is provided on the inlet side of the absorber 5 of the cooling water pipe 25 and the inlet temperature T2 of the cooling water. Is a temperature detecting means (hereinafter, referred to as a second temperature sensor) for detecting.

Reference numeral 34 is a control device built in a microcomputer or the like. The control device 34 operates by inputting temperature signals from the first and second temperature sensors 31 and 32, and operates as a fuel control valve. 21 is configured to output a required opening signal.

During operation of the double-effect absorption refrigerator, the refrigerant evaporated in the high temperature regenerator 1 passes through the low temperature regenerator 2 and then the condenser 3
After entering, condensing and liquefying by exchanging heat with water flowing in the condenser heat exchanger 27, the refrigerant flows to the evaporator 4 through the refrigerant pipe 17. Then, the refrigerant liquid exchanges heat with the water in the cold water pipe 22 to evaporate, and the water in the cold water pipe 22 is cooled by the heat of vaporization. The refrigerant evaporated in the evaporator 4 is absorbed by the absorbing liquid in the absorber 5.

Then, the absorption liquid which has absorbed the refrigerant and becomes thin in concentration is sent to the high temperature regenerator 1 through the low temperature heat exchanger 6 and the high temperature heat exchanger 7 by the operation of the absorption liquid pump 15. The absorbing liquid that has entered the high temperature regenerator 1 is heated by the gas burner 1B, the refrigerant evaporates, and the medium concentration absorbing liquid enters the low temperature regenerator 2 via the high temperature heat exchanger 7.

The absorbing liquid that has entered the low temperature regenerator 2 is heated by the refrigerant vapor flowing from the high temperature regenerator 1 through the refrigerant pipe 16, and the refrigerant is evaporated and separated to have a high concentration. The high-concentration absorption liquid (hereinafter referred to as the concentrated liquid) exchanges heat with the low-temperature heat exchanger 6 to lower the temperature, and then flows to the absorber 5 and is dispersed.

When the cold water outlet temperature T1 detected by the first temperature sensor 31 is, for example, 8 ° C. or higher, the controller 34 opens the fuel control valve 21 by 100% to open it at 7 ° C. or higher, 8 ° C.
If less than 50%, the opening degree of the fuel control valve 21 is set to 50%,
When the temperature is lower than 0 ° C, the opening degree of the fuel control valve 21 is set to 0%,
It has a so-called three-position control function.

Further, the control device 34 uses the second temperature sensor 3
The cooling water inlet temperature T2 detected by 2 is the first high temperature set value,
For example, when it becomes higher than 33 ° C. or when it becomes lower than the first low temperature set value, for example, 22 ° C., the maximum opening degree of the fuel control valve 21 is limited to, for example, 100% to 50%, and the high temperature regenerator 1 is controlled. A second high temperature setpoint, eg 32, which limits the amount of heating and is slightly below the first high temperature setpoint of 33 ° C and much higher than the first low temperature setpoint of 22 ° C.
Or lower than the first low temperature set value of 22 ° C. and much lower than the second high temperature set value of 32 ° C., for example, higher than 23 ° C.,
The maximum opening degree of the fuel control valve 21 is continuously limited to 50% until a predetermined time, for example, 20 minutes, and the maximum opening degree of the fuel control valve 21 is returned to the original value after waiting for the predetermined time to elapse.
It has a function to return it to 00%.

That is, the maximum opening of the fuel control valve 21 is
Based on the cooling water inlet temperature T2 detected by the second temperature sensor 32, for example, control is performed as shown in FIG.

In the control flow of FIG. 2, the opening degree of the fuel control valve 21 is increased or decreased in order to maintain the cold water outlet temperature T1 detected by the first temperature sensor 31 at a predetermined temperature (for example, 7 ° C.). It is configured as a three-position control subroutine control.

That is, a predetermined time (for example, 0.5 seconds)
Each time step S1 is started, the cooling water inlet temperature T2 detected by the second temperature sensor 32 is detected. In step S2, the cooling water inlet temperature T2 is 33 ° C. which is the first high temperature set value and the first high temperature set value. It is determined whether or not it is located between the low temperature setting value of 22 ° C.

When it is judged YES in step S2, the control is returned to the main control and the step S1 is started after a predetermined time. Alternatively, when it is determined that the temperature is lower than the first low temperature set value of 22 ° C., the process proceeds to step S3, the maximum opening of the fuel control valve 21 is limited to 100% to 50%, and heating in the high temperature regenerator 1 is performed. Limit the amount.

In step S4, the fuel control valve 21
The maximum opening degree of the high temperature regenerator 1 is limited to 50% and the elapsed time from the limitation of the heating amount in the high temperature regenerator 1 is measured, and step S5
Then, it is determined whether or not this elapsed time has passed a predetermined time, for example, 20 minutes.

When it is determined in step S5 that the predetermined time of 20 minutes has elapsed, the process proceeds to step S6, and the operation of detecting the cooling water inlet temperature T2 by the second temperature sensor 32 is executed again.

Then, in step S7, the cooling water inlet temperature T2 detected in step S6 is equal to the second low temperature set value of 2
It is determined whether or not the temperature is between 3 ° C. and the second high temperature setting value of 32 ° C. If the result is NO, the process returns to step S6 to detect the cooling water inlet temperature T2 by the second temperature sensor 32 and to perform the step. The above determination in S7 is repeated. When the determination is YES, the process proceeds to step S8, the maximum opening of the fuel control valve 21 is increased from 50% to 100%, and the restriction of the heating amount in the high temperature regenerator 1 is abolished. Return to main control.

As described above, the limited operation of the heating amount in the high temperature regenerator 1 which is performed by limiting the maximum opening degree of the fuel control valve 21 to 50% is continuously maintained for at least 20 minutes. A hammer sound is generated in the low temperature heat exchanger 6 and the high temperature heat exchanger 7 where the heating state changes in a short cycle and the absorption liquid pump 15 is frequently started and stopped, which was a win for the absorption refrigerator. However, it may be crystallized depending on the flow of the absorbing liquid, and the gas burner 1B, which is a heating device, and the absorbing liquid pump 15 are repeatedly started and stopped in a short cycle, which is disadvantageous in terms of durability. All the problems in the prior art are solved.

Further, as the control device 34, instead of the three-position control, when the cold water outlet temperature T1 detected by the first temperature sensor 31 is higher than a predetermined temperature, for example, 7 ° C., the opening degree of the fuel control valve 21 is changed. When the temperature is increased and is lower than 7 ° C., the fuel control valve 21 is configured so as to have a so-called capacity control function of narrowing the opening of the fuel control valve 21.

When the cooling water inlet temperature T2 detected by the second temperature sensor 32 is located between the low temperature set value, eg 28 ° C. and the high temperature set value, eg 32 ° C., the maximum opening degree of the fuel control valve 21 is set. Although it is 100%, when the temperature is lower than the low temperature set value of 28 ° C. and higher than the high temperature set value of 32 ° C., the maximum opening degree may be limited depending on the cooling water inlet temperature T2. it can.

For example, as shown in FIG. 3, when the cooling water inlet temperature T2 detected by the second temperature sensor 32 is higher than the high temperature set value of 32 ° C., the fuel control valve 21 is based on the cooling water inlet temperature T2. The maximum opening degree of the fuel control valve is proportionally limited at a rate of 10% / ° C, that is, at a rate of 10% per 1 ° C increase, and when the temperature is lower than the low temperature set value of 28 ° C, the fuel control valve is set based on the cooling water inlet temperature T2. The maximum opening degree of 21 is proportionally limited, for example, at a rate of 1% / ° C., that is, at a rate of 1% for a decrease of 1 ° C. to limit the heating amount in the high temperature regenerator 1.

Then, when the cooling water inlet temperature T2 detected by the second temperature sensor 32 becomes higher than the high temperature set value of 32 ° C. and becomes lower than the low temperature set value of 28 ° C., a predetermined time, for example, 20 For a minute, the maximum opening degree of the fuel control valve 21 is decreased based on the cooling water inlet temperature T2, and within this predetermined time, the cooling water inlet temperature T2 is in a temperature range higher than 32 ° C.
Shows a decreasing tendency or the cooling water inlet temperature T2 shows a rising tendency in a temperature range lower than 28 ° C., the maximum opening of the fuel control valve 21 is not increased and a predetermined time of 20 minutes elapses. If the cooling water inlet temperature T2 at that time is between the high temperature set value of 32 ° C. and the low temperature set value of 28 ° C., the control device 34 is configured to return the maximum opening degree of the fuel control valve 21 to 100%.

Further, the control device 34 keeps the cooling water inlet temperature T2 higher than the high temperature set value of 32 ° C. or low even after the maximum opening of the fuel control valve 21 is limited for a predetermined time (20 minutes in this case). When it is lower than the set value of 28 ° C., the maximum opening restriction operation is further continued for the predetermined time.

Even if the control device 34 is configured in this manner, the maximum heating amount limited operation in the high temperature regenerator 1 is maintained for at least 20 minutes, so that the absorption refrigerating machine to date has been advantageous. The heating state changes in a short cycle, the absorption liquid pump 15 is frequently started / stopped, a hammer sound is generated in the low temperature heat exchanger 6 and the high temperature heat exchanger 7, and the crystallization occurs depending on the flow of the absorption liquid. Sometimes
All the problems in the prior art such as the gas burner 1B, which is a heating device, and the absorbent pump 15 are repeatedly started and stopped in a short cycle, which is disadvantageous in terms of durability.

Since the present invention is not limited to the above embodiments, various modifications can be made without departing from the spirit of the claims.

For example, when the cold water outlet temperature T1 detected by the first temperature sensor 31 is higher than a predetermined temperature, the opening degree of the fuel control valve 21 is increased, and when the temperature is lower than the predetermined temperature, the opening degree of the fuel control valve 21 is reduced. The actual opening of the fuel control valve 21 is controlled by combining the control function and the maximum opening limit control of the fuel control valve 21 shown in FIG. 2 based on the cooling water inlet temperature T2 detected by the second temperature sensor 32. , High temperature regenerator 1
The controller 34 can also be configured to limit the amount of heating at.

When the cold water outlet temperature T1 detected by the first temperature sensor 31 is, for example, 8 ° C. or higher, the fuel control valve 21 is opened 100%, and when it is 7 ° C. or higher and lower than 8 ° C., the fuel control valve 21 is opened. Is 50% and the opening degree of the fuel control valve 21 is 0% when the temperature is less than 7 ° C. and the cooling water inlet temperature T detected by the second temperature sensor 32.
The control device 34 controls the actual opening of the fuel control valve 21 in combination with the maximum opening limit control shown in FIG. 3 of the fuel control valve 21 based on 2 to limit the heating amount in the high temperature regenerator 1. Can also be configured.

It is also possible to apply the maximum heating limit of the control for simply opening and closing the fuel control valve 21 based on the cold water outlet temperature T1 detected by the first temperature sensor 31.

After the maximum opening of the fuel control valve 21 is limited for a predetermined time, if the cooling water inlet temperature T2 detected by the second temperature sensor 32 is higher than the high temperature set value or lower than the low temperature set value, Although the operation of limiting the maximum opening is continued, the controller 34 is arranged to return the opening of the fuel control valve 21 to 100% as soon as the cooling water inlet temperature T2 returns between the high temperature setting value and the low temperature setting value. Can also be configured.

[0044]

The present invention is a heat input control method for an absorption refrigerating machine constructed as described above, in which the temperature of the cooling water supplied to the absorber / condenser rises or falls beyond the design range. Then, once the maximum heating amount of the heating device installed in the regenerator is limited, this maximum heating amount limiting operation is continued until a predetermined time elapses, so that repeated rapid state changes are prevented. For this reason, the next change occurs after the internal state of the aircraft is once stabilized, so that it is possible to prevent the occurrence of troubles that are difficult to predict.

In particular, at the solution surface in the regenerator, the regeneration temperature is once lowered, so that the fluctuation of the liquid surface due to the change of the void ratio is reduced, and the frequent start / stop of the absorbent pump is eliminated. For this reason, the durability of the absorption pump together with the heating device is improved.

Further, since the absorption liquid pump is not frequently started / stopped, it is possible to prevent the hammer noise from being generated in the heat exchanger.

Further, since the maximum heating amount of the heating device is limited and the heating amount in the regenerator is limited, the concentration of the absorbing liquid flowing out from the high temperature regenerator is lowered and crystallization is prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an absorption refrigerator according to an embodiment.

FIG. 2 is an explanatory diagram showing one control example.

FIG. 3 is an explanatory diagram showing another control example.

[Explanation of symbols]

 1 High Temperature Regenerator 1B Gas Burner 2 Low Temperature Regenerator 3 Condenser 4 Evaporator 5 Absorber 6 Low Temperature Heat Exchanger 7 High Temperature Heat Exchanger 8-12 Absorption Liquid Piping 15 Absorption Liquid Pump 16-18 Refrigerant Piping 19 Refrigerant Pump 20 Gas Piping 21 Fuel Control Valve 22 Cold Water Pipe 25 Cooling Water Pipe 26 Absorber Heat Exchanger 27 Condenser Heat Exchanger 28 Cooling Tower 30 Cooling Water Pump 31 First Temperature Sensor 32 Second Temperature Sensor 34 Control Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigenori Tateshita 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. The heating amount of a heating device installed in a regenerator that constitutes a refrigeration cycle by piping connection with an absorber, a condenser, an evaporator, etc. is controlled based on the temperature of cold water taken out from the evaporator. The maximum heating amount of the heating device is limited when the inflow temperature of the cooling water supplied to the absorber / condenser becomes higher than the first high temperature set value or becomes lower than the first low temperature set value. , Lower than the first high temperature set value and higher than the first low temperature set value and lower than the second high temperature set value, or higher than the first low temperature set value and lower than the second high temperature set value A heat input control method for an absorption refrigerating machine, which recovers when the temperature becomes higher than a second low temperature set value, wherein the inflow temperature of cooling water is higher than the first high temperature set value or the first low temperature. Maximum heating amount of the heating device becomes lower than the set value When the above condition is limited, the heat input control method for the absorption refrigerator is characterized in that the limiting operation of the maximum heating amount is continued at least until a predetermined time elapses even if the return condition is satisfied. 2. The heat input control method for an absorption chiller according to claim 1, wherein the maximum heating amount is returned to the original value when a condition for returning the maximum heating amount is satisfied and a predetermined time has elapsed. 3. The heating amount of a heating device installed in a regenerator, which is connected to an absorber / condenser / evaporator by piping, and is controlled based on the temperature of cold water extracted from the evaporator, Absorption refrigeration for limiting the maximum heating amount of the heating device based on the cooling water inflow temperature when the inflow temperature of the cooling water supplied to the absorber / condenser is higher than the high temperature set value or lower than the low temperature set value. A heat input control method for a machine, wherein when the inflow temperature of cooling water is higher than the high temperature set value or lower than the low temperature set value to limit the maximum heating amount of the heating device, at least a predetermined time has elapsed. The heat input control method for an absorption chiller, characterized in that the limited operation of the maximum heating amount is continued until the above. 4. The absorption refrigerating machine according to claim 3, wherein when the cooling water inflow temperature returns between a high temperature setting value and a low temperature setting value and a predetermined time elapses, the maximum heating amount of the heating device is restored. Thermal control method.