JPS58117978A - Controller for absorption refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an absorption refrigerator, and more particularly to a control device for a bob inside an absorption refrigerator.

Generally, the temperature of cold water in an absorption refrigerator is controlled by adjusting the heating source so as to maintain the temperature of the cold water at a predetermined temperature. Adjustment control of this heating source includes on/off control that starts heating when the cold water temperature reaches the upper limit and stops heating when it reaches the lower limit, and the difference between the current cold water temperature and the lower limit. Proportional control is used to continuously control the amount of heating depending on the amount of heat.

In conventional on/off control or proportional control of the heating source, only the heating source is adjusted in order to maintain the chilled water temperature at a predetermined value. However, in reality, the amount of heat generated changes the temperature and concentration of the solution within the generator. This is transmitted by the flow of the solution and causes the absorption action of the solution in the absorption section and the evaporation action of the refrigerant in the evaporator, thereby lowering the temperature of the cold water.

That is, even if heating is stopped due to a drop in cold water temperature, the generator, absorber, and evaporator have an extremely high refrigerating capacity that will not cause the dropped cold water temperature to rise immediately. Conventionally, the temperature of chilled water has been controlled only by adjusting the heating source, which has not only ignored this refrigeration capacity and not used it effectively, but also caused the refrigeration capacity to be immediately used as dilution. If you do something like turn the cold water temperature down, you're consuming extra energy for reheating.

The present invention has been made based on the above-mentioned matters, and by effectively utilizing the refrigeration capacity accumulated in the refrigerator by heating, it is possible to suppress the rise in temperature of cold water after heating has stopped, and to reduce the amount of heating. The purpose is to prevent excessive consumption of

The feature of the present invention is that the heating source t-
In devices that adjust and control the chilled water temperature to a predetermined temperature, when the chilled water temperature falls to a predetermined temperature and the heating source is stopped, the solution chip J refrigerant pump In addition to operating these pumps, the solution pump and refrigerant pump are operated when the cold water temperature is decreasing.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a system diagram of an absorption refrigerator equipped with an example of the control device of the present invention. The refrigerator F includes a generator 2 that heats a dilute solution using a heating medium heated by a heating source 1 to generate refrigerant vapor (steam), and a generator 2 that passes the refrigerant vapor generated by the desensitizer 2 through a cooling water pipe 3. a condenser 4 that is cooled and liquefied by cooling water; a cold tIX that is liquefied in the condenser 4;
An evaporator 6 that completely evaporates the liquid and removes the latent heat of vaporization from the water flowing in the cold water pipe 5 to generate cold water (cold power) sound, a pump 7 for circulating the refrigerant of the evaporator 6, and a pump 7 for circulating the coolant inside the cooling water pipe 3. An absorber 8 generates a dilute solution by absorbing the refrigerant vapor evaporated in the evaporator 6 into a concentrated solution introduced from the generator 2 while being cooled by flowing cooling water, and a generator absorbs the dilute solution generated in the absorber 8. Heat is exchanged between the #liquid pump 9 that pumps #2, the still-temperature concentrated solution returned from the generator 2 to the absorber 8, and the low-temperature dilute solution supplied from the absorber 8 to the generator 2. It is composed of a heat exchanger 10.

11 is a temperature detector that detects the cold water temperature f and t in the cold water pipe 5; 12 is a temperature detector that detects the solution temperature in the heat exchanger 10; 13 is an air conditioner serving as a load for the refrigerator F; 14 is a control Based on the detection signal from the temperature detector 11, this control device 14 controls the heating source 1 and also controls the temperature detector 1 in order to control the cold water temperature [1-predetermined temperature].
Based on the detection signal from 2, the solution pump 9 and the refrigerant pump 7 are controlled.

In the absorption chiller described above, the cold water temperature 1fi- can be controlled by on/off control or proportional control of the heating source 1t.
The temperature is controlled at a predetermined level. First, when the control device of the present invention is applied to an absorption refrigerator that controls on/off of t1, tiq
I will clarify.

FIG. 82 is a time chart showing an operation pattern when p on/off control is performed by the control device of the present invention. In on-off control, when cold water i[T reaches the upper limit, heating source 1t
ONL, operate pump 7゜9 at the same time. As a result, the cold water temperature T gradually decreases, and when it reaches the lower limit, the heat source 1 is turned off. By repeating this, the cold water@degree T is controlled along a predetermined temperature range. As shown in FIG. 1, since a large amount of heat medium is interposed between the heating source 1 and the cold water pipe 5, the heating source 1? Even if they are turned off, they still have a high refrigeration capacity.

Conventionally, after turning off the heat source 1, the pump 7.
This is a method of driving 9. This method turns off the heating source by 1t
If pump 7.9 is stopped immediately after L7'j,
Since the refrigerating output of the refrigerator disappears, the cold water temperature immediately rises from point B to point D1. For this reason, the powerful refrigerating capacity of the refrigerator as described above is not utilized, and the frequency of heating during on/off control increases, consuming excess energy. On the other hand, there is a system in which the pump 7.9 is operated regardless of the solution temperature. In this method, even after the heating source is turned off for 1t, the pump 7.9 continues to operate, so the powerful refrigeration capacity mentioned above is utilized, and the chilled water temperature gradually drops from point B to point 0 to point D2. and rise. However, if the pump 7.9 continues to operate without heating, the concentration of the solution will drop significantly, and the time required to turn on the heating source 1 t will be longer than before, which will end up consuming extra energy. Become. Therefore, in the control device of the present invention, the heating source 1
After turning OFF the pump 7.91c, the pump 7.91c is operated until the temperature of the solution in the heat exchanger 10 detected by the temperature detector 12 becomes a predetermined temperature or less.
While the chilled water temperature is decreasing due to the operation, the pump is operated at 7.9 tons. Therefore, since the powerful refrigeration capacity mentioned above is utilized, the cold water @ degree is reduced from point B to 0.
drop to a point. At the 0 point, the cold water @counterfeit does not drop any further, so the pump 7.9 is stopped.

Therefore, although the cold water temperature immediately increases from point FiC to point D, the concentration of the solution does not decrease.

Next, since the time required to apply 1 tOH of the heating source is not much different from that of the conventional method, energy can be used effectively. The point in time when the cold water temperature does not decrease is determined by detecting that there is no change in the cold water temperature at two points separated by a short time interval. In practice, this is determined by detecting that the difference in cold water temperature between two points in time has become less than a certain value. More precisely, it is determined by detecting that the differential value of the cold water temperature at each point in time becomes zero or below a certain value.

In normal refrigerators, if the cold water temperature drops too much, the cold water will freeze or the internal state will become unbalanced, so a minimum temperature of the cold water is determined. Therefore, it is necessary to stop operation of the pump according to the method of the present invention at a predetermined cold water temperature before this temperature is reached. When the load is large, the temperature of the cold water decreases due to the operation of the pump according to the control of the present invention, but it rarely decreases to the above-mentioned predetermined temperature, and the temperature of the cold water also increases due to the operation of the pump.
Stop the pump at this point. On the other hand, if the pump is operated when the load is small, the chilled water temperature may drop.
Stop the pump at this point.

Furthermore, if the chilled water temperature is rising, the refrigerant pump 7
drive only. This makes it possible to effectively utilize the refrigerant's refrigerating ability. In this case, operating the solution pump is not a good idea since there is no heating and the concentration of the solution is unnecessarily diluted, increasing the amount of subsequent heating. Further, since there is a limit to the refrigerating capacity of the refrigerant, in consideration of this, a method of stopping the refrigerant pump 7tP may be considered if the chilled water temperature suddenly rises.

The above explanation has been made using on-off control as an example, but in the case of proportional control, a similar control method can be applied if the temperature range between the temperature at which the heating source is turned on and the temperature at which the heating source is turned off is set in a proportional band.

Note that the control device 14 can be realized by an electronic circuit or a microcomputer.

As described above, according to the present invention, the frequency of heating can be reduced by 1 in on-off control, and the amount of heating can be reduced in proportional control, resulting in a large energy-saving effect. Further, since the temperature of the cold water is maintained near the lower limit value for a long time, the cooling capacity is uniformized, which is advantageous from the viewpoint of comfort.

[Brief explanation of the drawing]

Fig. m1 is a system diagram of an absorption refrigerator equipped with an embodiment of the control device of the present invention, and Fig. 2 is a time chart illustrating the control operation of the present invention. 1... Heating source q2... Generator, 3... Cooling water pipe,
4... Condenser, 5... Cold water pipe, 6... Evaporator, 7
... Refrigerant pump, 8 ... Absorber, 9 ... Solution pump, 10 ... Heat exchanger, 11 ... Cold water m degree detector,
12...Solution @ temperature detector, 13...Air conditioner, 14.
··Control device. Agent Patent Attorney Toshiyuki Usuda

Claims (1)

[Scope of Claims] 1. In an absorption chiller in which the temperature of chilled water is controlled to a predetermined temperature by adjusting the heat source t, when the chilled water temperature falls to a predetermined temperature and the heating source is stopped, The control unit operates the solution pump and refrigerant pump according to the temperature of the solution at a predetermined position, and also operates the solution pump and refrigerant pump when the chilled water temperature is decreasing or decreasing to a predetermined @K by operating these pumps. A control device for an absorption chiller, characterized by comprising: 2. The control unit operates the solution pump and the refrigerant pump when the differential value of the descending cold water@degree is above a predetermined speed. . & The control device for an absorption chiller according to claim #11, wherein the control unit operates the refrigerant pump when the temperature of the chilled water is rising.