JP3182233B2 - Operation control method in absorption refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling the operation of an absorption refrigerator using an aqueous solution of lithium bromide as an absorbing liquid and water as a refrigerant, and more particularly to a method of controlling the operation of a diluent pump to form a chilled water outlet. The present invention relates to a technique for preventing temperature hunting and the like.

[0002]

2. Description of the Related Art The technology of an absorption refrigerator that controls the operation of a diluent pump provided in a diluent pipe from an absorber to a regenerator according to the level of an absorbing liquid in a regenerator is disclosed in Japanese Patent Application Laid-Open No. 62-8426.
No. 7, JP-A-62-116871 and the like.

[0003] The absorption refrigerator proposed in Japanese Patent Application Laid-Open No. 62-84267 discloses an absorption refrigerator based on a physical quantity in the machine that changes in response to a change in load, for example, the temperature and liquid level of the absorbent in a regenerator. It has a function (action) that adjusts the discharge amount of the diluent pump provided in the diluent pipe from the regenerator to the regenerator so that the diluent supply amount to the regenerator matches the partial load. When a partial load is generated, the regenerator can efficiently generate the refrigerant vapor.

Further, since the cooling water pump and the discharge amount of the cooling water pump are also adjusted, the refrigeration output controllability in response to the load change is excellent, and the refrigeration output corresponding to the partial load can be reduced in a short time. In addition to being able to demonstrate, the power consumption of these pumps can be saved.

However, in this absorption refrigerator, since the operation of the diluent pump is stopped when the liquid level in the regenerator is high, the refrigerant vapor absorption capacity of the absorber increases due to the increase in the absorption liquid concentration, and the chilled water outlet temperature rises. On the other hand, when the operation of the diluted liquid pump is restarted, the chilled water outlet temperature rises, so that there is a problem that so-called hunting occurs in the chilled water outlet temperature. Further, since the flow rate of the absorbing liquid changes rapidly due to the stoppage of the diluent pump, the balance such as a sudden increase in the regenerator pressure or an increase in the regenerator temperature is lost, and the liquid level of the regenerator decreases, the pressure increases, and the temperature increases. This causes a problem that even if the rotation speed of the diluent pump is increased, the liquid level, pressure, and temperature change greatly, and the absorption refrigerator stops abnormally.

On the other hand, the device for notifying the abnormal operation of an absorption refrigerator proposed in Japanese Patent Application Laid-Open No. Sho 62-116871 is capable of easily knowing a place where an abnormality has occurred and a place where an abnormality may occur. It is not intended to improve the operation function of the absorption refrigerator.

Also, in this case, since the diluent pump is simply started and stopped, the problem of the absorption refrigerator disclosed in Japanese Patent Application Laid-Open No. 62-84267 is similarly encountered.

[0008]

That is, a technique for controlling the operation of a diluent pump provided in a diluent pipe from an absorber to a regenerator by controlling the temperature and level of the absorbing liquid in the regenerator is well known. However, in any case, there is a problem that the pressure and the flow rate of the refrigerant and the absorbing liquid rapidly change, and the balance inside the device is lost, and solving this point has been a problem.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and comprises a regenerator, a condenser, an evaporator, an absorber, and a heat exchanger connected by piping. In the absorption refrigerator, when the liquid level of the absorbent in the regenerator exceeds a predetermined height, the diluent pump provided in the diluent pipe from the absorber to the regenerator is operated at the lowest speed, and this lowest speed operation is performed. It is an object of the present invention to provide an operation control method in an absorption refrigerator, characterized in that the operation of the diluent pump is stopped when a predetermined period of time has elapsed, thereby solving the problem of the related art.

[0010]

[0011]

According to the operation control method of the present invention, for example, the pressure of the condenser decreases due to the rapid decrease of the cooling water temperature, the pressure of the regenerator also decreases, and the level of the absorbent in the regenerator becomes a predetermined level. When the pressure exceeds the threshold, the diluent pump operates at the lowest speed, so that the temperature of the absorbent does not change significantly, hunting of the chilled water outlet temperature is avoided, and the amount of diluent flowing into the regenerator is reduced. The heating of the regenerator gradually increases the pressure and temperature of the regenerator and lowers the liquid level. For this reason, within a while, the liquid level becomes lower than the predetermined height,
Mixing of the absorbing liquid into the refrigerant vapor due to a large rise in the liquid level is prevented.

[0012] Even when the lowest speed operation of the diluted liquid pump is performed, the liquid level of the absorbing liquid exceeding a predetermined height does not decrease.
When the operation of the diluted pump continues for a predetermined time, the operation of the diluted pump completely stops, and the flow of the diluted liquid into the regenerator completely stops. Even if an abnormality such as clogging of a pipe or clogging of a low-temperature heat exchanger that exchanges heat between a diluted liquid and a concentrated liquid occurs, the liquid level in the regenerator rises and the absorbing liquid is mixed into the refrigerant vapor. Nothing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. 1. 1 is a high-temperature regenerator, 2 is a low-temperature regenerator, 3 is a condenser,
Is an evaporator, 5 is an absorber, 6 is a high-temperature heat exchanger, 7 is a low-temperature heat exchanger, and the equipment itself is disclosed in JP-A-62-2426.
There is no particular difference from that used in the conventionally known double-effect absorption refrigerator disclosed in Japanese Patent No. 7 and the like.

That is, since the main structure of the absorption refrigerator is the same as that of the conventional one, the dilution pipe 1 having the dilution pump P1 is provided between the solution reservoir of the absorber 5 and the high temperature regenerator 1.
Piping 1

A refrigerant vapor pipe 12 having a valve V1 is piped so that refrigerant vapor evaporated and separated in the high-temperature regenerator 1 by heating the burner 10 and the like can flow into the condenser 3 after heat exchange in the low-temperature regenerator 2. ,

A refrigerant liquid pipe 13 is provided so that the refrigerant liquid condensed by heat exchange in the condenser 3 flows into the evaporator 4.

A refrigerant circulation pipe 14 having a refrigerant pump P2 is provided so that the refrigerant liquid in the refrigerant liquid pool of the evaporator 4 can be sprayed from the spraying means 21 provided on the upper side of the evaporator 4.

The intermediate liquid pipe 15 is connected to the intermediate liquid pipe 15 so that the intermediate liquid having a high absorption liquid concentration by separating the refrigerant vapor in the high temperature regenerator 1 can flow into the low temperature regenerator 2 via the high temperature heat exchanger 6. ,

The concentrated liquid whose absorption liquid concentration is further increased in the low-temperature regenerator 2 passes through the low-temperature heat exchanger 7, and is connected to the concentrated liquid pipe 16 so that it can be sprayed from the spraying means 22 of the absorber 5. And an absorption liquid circulation path.

In order to cool the interior of the absorber 5 and the condenser 3, a cooling water pipe 31 through which river water or the like is passed is piped so as to be able to exchange heat via the absorber 5 and the condenser 3 in this order. A chilled water pipe 32 capable of exchanging heat in the evaporator 4 and supplying chilled water is provided.

In the double effect absorption refrigerator of the present embodiment, the bypass pipe 12A is branched from the refrigerant vapor pipe 12 before the valve V2 via the valve V2 so as to be able to communicate with the absorber 5, and is connected to the pipe. Therefore, by switching the opening and closing of the valves V1 and V2, it is possible to supply cold water or hot water from the cold water pipe 32.

Then, in order to detect the level of the absorbing liquid 8 in the high temperature regenerator 1, three level sensors S1, S2,.
S3 is installed vertically at a predetermined interval.

That is, the lowermost level sensor S1 detects the shortage of the absorbing liquid 8, and the uppermost level sensor S3 detects the excess of the absorbing liquid 8. The sensor S2 detects that the excess absorbing liquid 8 has returned to the normal range, and the level sensor S2 is installed to be offset from the level sensor S3.

These level sensors S1, S2, S3 are:
For example, the output voltage is formed by an electrode or the like based on the measurement principle of conduction of the electrolytic solution, and the output voltage changes depending on the presence or absence of contact with the absorbent 8.

The level sensors S1, S2, S3
The controller 9 is connected and installed so as to output a control signal to the dilute liquid pump P1 in response to the signal output from the controller and to control the operation of the pump.

For example, if the diluted liquid pump P1 is an inverter pump whose frequency is controlled, an inverter is provided in the control device 9 so as to be able to convert the frequency, and a predetermined high voltage is input from the uppermost level sensor S3, Absorbent 8 in regenerator 1
When it is confirmed that a large amount of
Outputs a control signal, that is, the lowest frequency, for example, 30 Hz, and the absorbent pump P1 rotates at the lowest speed (for example,
00 rpm).

When it is confirmed that the operation at the lowest rotation speed has continued for a predetermined period of time, for example, 5 minutes by a timer (not shown) provided in the control device 9, for example, an operation stop signal is sent from the control device 9. Is output, and the operation of the diluted liquid pump P1 is stopped.

On the other hand, when a predetermined low voltage is input from the level sensor S1 provided at the bottom, the high-temperature regenerator 1
When it is confirmed that the pressure is insufficient, the control device 9 outputs the highest frequency, for example, 60 Hz, so that the diluent pump P1 can be operated at the highest speed (for example, 3600 rpm).

A predetermined high voltage is input from the lowermost level sensor S1, a predetermined lower voltage is input from the uppermost level sensor S3, and the absorption liquid 8 is supplied to the level sensor S1.
When it is confirmed that the value is between 1 and S3, the control device 9 outputs a rated frequency, for example, 50 Hz, as a control signal, and drives the diluted pump P1 to the rated rotation speed (for example, 30 Hz).
00 rpm).

The burner 1 for heating the high-temperature regenerator 1
The thermal power of 0 can be controlled by opening and closing the opening of the fuel control valve 10A, for example, in response to (for example, in proportion to) the thermal load.

Therefore, the pressure of the condenser 3 and the pressure of the high-temperature regenerator 1 decrease due to a sharp decrease in the temperature of the cooling water flowing through the cooling water pipe 31 and the like. Since the pump P1 operates at the lowest speed, the cold water pipe 3
Hunting of the outlet temperature of the cold water flowing through 2 does not occur.

Even if the concentrated liquid pipe 16 becomes clogged or the like, the diluted liquid pump P
Since 1 stops, the absorbing liquid does not mix into the refrigerant vapor.

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

For example, the level sensor for detecting the level of the absorbing liquid in the high-temperature regenerator 1 may be configured to detect only the upper and lower S1 and S3, or may be a sensor using a capacitance type liquid level meter. Then, the liquid level can be detected by one sensor.

[0035]

As described above, according to the operation control method of the present invention, for example, the temperature of the cooling water is greatly reduced, the pressure of the condenser is reduced, and the pressure of the regenerator is further reduced. Even if the liquid level of the absorbing liquid exceeds the predetermined height, the hunting of the cold water outlet temperature can be achieved by rotating the diluted liquid pump at the lowest speed to reduce the inflow to the regenerator and wait for the liquid level to return. If the liquid level does not decrease even if this minimum speed operation is continued for a predetermined time, the operation of the diluent pump is stopped to stop the flow of dilute liquid into the regenerator. As a result, the absorption liquid is not mixed with the refrigerant vapor, and the internal state of the absorption refrigerator is not adversely affected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High temperature regenerator 2 Low temperature regenerator 3 Condenser 4 Evaporator 5 Absorber 6 High temperature heat exchanger 7 Low temperature heat exchanger 8 Absorbent 9 Control device 10 Burner 11 Rare liquid pipe 12 Refrigerant vapor pipe 13 Refrigerant liquid pipe 14 Refrigerant circulation Pipe 15 Intermediate liquid pipe 16 Concentrated liquid pipe 21 ・ 22 Spraying means 31 Cooling water pipe 32 Cold water pipe S1, S2, S3 Level sensor P1 Rare liquid pump P2 Refrigerant pump

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 15/00 306

Claims (1)

(57) [Claims] 1. An absorption refrigerator comprising a regenerator, a condenser, an evaporator, an absorber, and a heat exchanger connected to a pipe, when the level of the absorbent in the regenerator exceeds a predetermined level. An absorption refrigerating machine, wherein a diluent pump provided in a diluent pipe from the absorber to the regenerator is operated at a minimum speed, and when the minimum speed operation is continued for a predetermined time, the operation of the diluent pump is stopped. Operation control method.