JPH0236868B2 - KYUSHUREITOKISEIGYOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption refrigerator control device.

An example of a conventional absorption refrigerator control device will be explained based on FIG. 1. The one shown in FIG. 1 is a double-effect absorption refrigerator that uses water as the refrigerant and an aqueous lithium bromide solution as the absorbent (solution).

In the figure, 1 is a high-pressure regenerator, 2 is a low-pressure regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low-temperature heat exchanger, 7 is a high-temperature heat exchanger, 8 to 13 are solution piping , 14 is a regenerator pump, 15 is an absorber pump, 16 is an ejector, 17 to 19 are refrigerant pipes, 20 is a refrigerant pump, 21 is a heat source pipe, 22
23 is a cooling water pipe, 23 is a chilled water pipe, and 24 is a cooling water pump. The pipes are connected as shown in the figure. The refrigerant evaporated in the high pressure regenerator 1 passes through the low pressure regenerator 2 and enters the condenser 3, and the cooling water is supplied to the condenser 3. After exchanging heat with the water in the pipe 22 to condense and liquefy, it enters the evaporator 4 and flows into the cold water pipe 23
The water in the cold water pipe 23 is cooled by the heat exchanged with the water inside and evaporated, and the heat removed at this time cools the water inside the cold water pipe 23.

On the other hand, the refrigerant evaporated in the evaporator 4 is absorbed by a solution in the absorber 5, and the solution, which has become diluted by absorbing the refrigerant, is transferred to a low-temperature heat exchanger 6,
The refrigerant enters the high-pressure regenerator 1 through the high-temperature heat exchanger 7, where it is heated by the heat source supplied through the heat source piping 21, evaporates and separates the refrigerant, and becomes a medium-concentration solution. The refrigerant then enters the low-pressure regenerator 2, where it is heated by refrigerant vapor, and the refrigerant is further evaporated and separated, increasing its concentration. The solution that has become highly concentrated in the low-pressure regenerator passes through the low-temperature heat exchanger 6, mixes with the solution from the absorber pump 15 in the ejector 16, and is distributed into the absorber 5, thereby performing a refrigeration cycle. .

Conventionally, in the above-mentioned dual-effect absorption refrigerator, a chilled water outlet temperature detector 25 detects the chilled water outlet temperature, and a comparator 27 compares this with a chilled water outlet temperature target value set in a temperature setting device 26. Then, the flow rate adjustment valve 29 is controlled via the flow rate regulator 28 to adjust the flow rate of the heating source, and the solution level in the high-pressure regenerator 1 is detected by the liquid level detector 30. The comparator 32 compares the liquid level with the set liquid level target value, and the circulating amount control valve 3
4 to control the circulation amount of the solution, the capacity is controlled in accordance with the load.

However, the conventional feedback control device described above only controls the chilled water outlet temperature and the solution level in the high-pressure regenerator. There was a risk that the concentration of the absorbent would become too high and the absorbent would crystallize, damaging the pump or clogging the piping, making it inoperable.

The present invention has been proposed in view of the above-mentioned points, and an object thereof is to provide an absorption refrigerating machine control device that can reliably prevent crystal precipitation and perform stable operation.

The absorption chiller control device of the present invention includes a control system that detects the cold water outlet temperature and controls the amount of heat source to the regenerator, and a control system that detects the solution level in the regenerator and controls the amount of solution circulated from the absorber to the regenerator. In addition, a control system is provided to control the temperature of the condensed refrigerant or the pressure inside the regenerator, the temperature of the concentrated solution at the outlet of the regenerator, and the temperature of the concentrated solution at the outlet of the solution heat exchanger, and from these, the crystal concentration margin of the solution is determined. The present invention is characterized in that the heating source amount control system is provided, which calculates the amount of heat source and determines an appropriate value of the amount of heat source as a function of the margin when the margin becomes equal to or less than a predetermined value.

The absorption chiller control device of the present invention also includes a control system that detects the chilled water outlet temperature and controls the amount of heat source to the regenerator, and a control system that detects the level of solution in the regenerator and controls the flow of solution from the absorber to the regenerator. A control system is provided to control the amount of circulation, and the temperature of the condensed refrigerant or the pressure inside the regenerator is
Detect the concentrated solution temperature at the outlet of the regenerator and the concentrated solution temperature at the outlet of the solution heat exchanger, calculate the crystal concentration margin of the solution from these, and when the margin falls below a predetermined value, calculate the margin. The present invention is characterized in that a control system is provided which determines an appropriate value of the solution circulation amount as a function and controls the solution circulation amount control system to increase the solution circulation amount. Calculate the crystal concentration margin of the solution as described above, and when this falls below a predetermined value, calculate the appropriate value for the amount of heat source as a function of this and reduce the amount of heat source so as not to cause crystal precipitation. This can prevent crystal precipitation. Also,
Similarly, crystal precipitation can also be prevented by finding an appropriate value for the solution circulation amount as a function of the crystal concentration margin and increasing the solution circulation amount. Therefore, it is possible to accurately control the capacity with respect to the load, reliably prevent crystal precipitation, and operate with a high solution concentration, so that efficiency can be improved.

The present invention will be explained below based on illustrated embodiments.
In FIG. 2, numerals 1 to 34 are similar to those shown in FIG. 1, and perform the same functions.

In this embodiment, a temperature detector 101 detects the temperature of the condensed refrigerant, a temperature detector 102 detects the temperature of the concentrated solution at the outlet of the low-pressure regenerator 2, and a temperature detector 102 detects the temperature of the concentrated solution at the outlet of the high-temperature heat exchanger 6. A temperature detector 103 and a calculation device 104 such as a microcomputer that calculates the crystal concentration margin of the solution from these detected values as described later are provided, and the concentration margin outputted from the calculation device 104 is set to a predetermined value. When the following conditions occur, function generators 105 and 106 are provided to determine appropriate values for the amount of heat source and the amount of solution circulated from a preset function. The heat source amount control valve 29 and the solution circulation amount control valve 34 are controlled through the heat source amount control valve 29 and the solution circulation amount control valve 34.

In the above configuration, the function generator 105 has a predetermined appropriate function that reduces the amount of heat source when the concentration margin becomes less than a predetermined value.
The function generators 106 are each set with a predetermined appropriate function that increases the amount of solution circulated.

On the other hand, the crystal concentration margin ΔX of the solution is calculated from the concentration curve of the lithium bromide solution shown in FIG. 3 as follows.

The concentration of the solution X ₁ is determined by the pressure P ₁ in the low pressure regenerator 2 calculated from the condensed refrigerant temperature T ₁ from the detector 101 and the saturation characteristics of water, and the low pressure regenerator outlet solution temperature T ₂ from the detector 102. _The difference ( _△ X=X ₁ −X ₂ ).

Here, if the concentration margin △X becomes △X<0, crystal precipitation will occur, so to prevent this, either reduce the amount of heating source or increase the amount of solution circulation. , or both operations. When the concentration margin ΔX becomes less than a certain value, the function generators 105 and 106 output corresponding outputs according to a preset function, and the comparator 107 outputs corresponding outputs according to a preset function. , 108 and control valves 29, 34
The amount of heat source is reduced and the amount of solution circulated is increased via. Therefore, it is possible to reliably prevent crystal precipitation and eliminate the drawbacks of conventional products.

Note that it is clear from the above description that a pressure detector for detecting the pressure within the low pressure regenerator may be provided in place of the temperature detector 101 in the above embodiment.

Furthermore, it goes without saying that the present invention can be similarly applied to a single-effect absorption refrigerator.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional one, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a concentration curve diagram of a lithium bromide solution. 1: High pressure regenerator, 2: Low pressure regenerator, 3: Condenser, 4: Evaporator, 5: Absorber, 6: Low temperature heat exchanger, 7: High temperature heat exchanger, 8 to 13: Solution piping,
14: Regenerator pump, 15: Absorber pump, 1
6: Ejector, 17 to 19: Refrigerant piping, 2
0: Refrigerant pump, 21: Heat source piping, 22: Cooling water piping, 23: Chilled water piping, 24: Cooling water pump,
25: Chilled water outlet temperature detector, 26: Temperature setting device,
27: Comparator, 28: Controller, 29: Heat source amount control valve, 30: Liquid level detector, 31: Liquid level setter, 32: Comparator, 33: Controller, 34:
Solution circulation amount control valve, 101, 102, 103: Temperature detector, 104: Computing device, 105, 106:
Function generator, 107, 108: Comparator.

Claims (1)

[Claims] 1. A control system that detects the cold water outlet temperature and controls the amount of heat source to the regenerator, and a control system that detects the solution level in the regenerator and controls the amount of solution circulated from the absorber to the regenerator. In addition to providing a control system, the temperature of the condensing refrigerant or the pressure inside the regenerator, the temperature of the concentrated solution at the outlet of the regenerator, and the temperature of the concentrated solution at the outlet of the solution heat exchanger are detected, and the crystal concentration margin of the solution is calculated from these. , characterized in that a control system is provided that determines an appropriate value of the amount of heat source as a function of the margin when the margin becomes equal to or less than a predetermined value, and controls the heating source amount control system to reduce the amount of the heat source. Absorption chiller control device. 2 A control system that detects the cold water outlet temperature and controls the amount of heat source to the regenerator, and a control system that detects the solution level in the regenerator and controls the amount of solution circulated from the absorber to the regenerator are installed. Detect the refrigerant temperature or pressure inside the regenerator, the concentrated solution temperature at the outlet of the regenerator, and the concentrated solution temperature at the outlet of the solution heat exchanger, calculate the crystal concentration margin of the solution from these, and check if the margin is below a predetermined value. An absorption refrigerating machine control device comprising: a control system that determines an appropriate value of the solution circulation amount as a function of the margin when the solution circulation amount becomes equal to 1, and controls the solution circulation amount control system to increase the solution circulation amount.