JPH0379629B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a control device for an absorption refrigerator.

In general, absorption refrigerators use low-temperature fluids such as solar hot water or factory waste water as the main heat source, and high-temperature, high-pressure steam gas, combustion gas such as oil, or other high-temperature fluids as the auxiliary heat source. It is required to save as much as possible and utilize the main heat source rationally to obtain cold water for cooling or hot water for heating according to the load.

In order to meet such requests, the temperature of the load fluid such as cold water or hot water, which is the load that needs to be supplied with an auxiliary heat source, is set to a certain value, and when the load increases beyond the load corresponding to the set temperature, the A method has been proposed in which the supply amount of the auxiliary heat source is controlled in proportion to the load increment and the control signal is adjusted in inverse proportion to the main heat source temperature (cold fluid temperature). For example, as shown in Figure 1, when the chilled water temperature for air conditioning is 6℃, in other words, when the load increases from almost no load and the chilled water temperature reaches 7.5℃, the main heat source supply amount reaches 100%. The main heat source control valve is proportionally controlled so that the supply of the auxiliary heat source is started, and when the load increases and the chilled water temperature reaches 9℃, when the main heat source temperature is below 75℃ We aim to save on auxiliary heat sources by proportionally controlling the auxiliary heat source control valve so that 100% of the auxiliary heat source is supplied and 50% of the auxiliary heat source is supplied when the main heat source temperature is 85°C or higher. There is.

However, although such a method makes it possible to save on the auxiliary heat source, it has the disadvantage that the main heat source cannot be utilized rationally. In other words, as shown in Fig. 1, for example, in the auxiliary heat source control valve, the main heat source temperature is
When the temperature of the main heat source is 85℃ or higher, the maximum opening is 50%, and when the main heat source temperature is 75℃ or lower, the maximum opening is 100%.
The main heat source control valve is adjusted according to the main heat source temperature, but the opening degree of the main heat source control valve is uniformly controlled regardless of the main heat source temperature, and the main heat source supply is adjusted according to the amount of thermal energy of the main heat source fluid. It has no drawbacks.

In addition, with this method, even if the load does not change, it is necessary to adjust the supply amount of the auxiliary heat source in inverse proportion to the change in the main heat source temperature (for example, in Figure 1, if the chilled water temperature remains at 9°C and does not change), Even if the main heat source temperature is from 75℃
When the temperature rises to 85℃, the auxiliary heat source control valve opening degree is set to 100%.
To do this, for example, connect a signal conversion potentiometer for the main heat source temperature in series with a signal conversion potentiometer for the chilled water temperature, and reduce the supply amount of both potentiometers and the auxiliary heat source. It has the disadvantage that it requires a complicated control circuit, such as a bridge circuit consisting of a signal conversion feedback potentiometer and a balancing relay.

In view of these points, the present invention changes the load fluid set temperature at which supply of the main heat source and the auxiliary heat source is started in accordance with the temperature of the main heat source, and also changes the main heat source valve and the auxiliary heat source valve in accordance with the load fluid temperature. Adopt a simple configuration consisting of a temperature controller that outputs a signal to control the opening degree, and a controller that inputs the signal from the temperature controller to control the opening degree of the main heat source valve or auxiliary heat source valve. This aims to control the amount of heating to the regenerator according to the amount of thermal energy of the main heat source fluid, save on the auxiliary heat source, and provide a rational heat source according to the load.

Hereinafter, one embodiment of the present invention will be described based on the drawings. In Figure 2, 1 is a low-temperature heat source regenerator that heats and separates refrigerant from a dilute liquid using a low-temperature fluid such as solar hot water as the main heat source, and 2 is a low-temperature heat source regenerator that uses a high-temperature fluid such as oil or other combustion gas as an auxiliary heat source to transfer refrigerant from the primary intermediate liquid. 3 is a low-temperature regenerator that heats and separates the refrigerant from the secondary intermediate liquid using the refrigerant vapor separated by the high-temperature heat source regenerator 2 as a heat source;
4 is a condenser that cools and condenses the refrigerant separated by each of the regenerators 1, 2, and 3; 5 is a condenser that uses latent heat when dispersing and vaporizing the liquid refrigerant from the condenser 4 to generate cold water for air conditioning; The evaporator 6 maintains a low pressure inside the evaporator 5 by dispersing the concentrated liquid regenerated by the regenerators 1, 2, and 3 and absorbing the vaporized refrigerant, thereby continuously supplying cold water. 7 and 8 are low-temperature heat exchangers and high-temperature heat exchangers, which are connected to a refrigerant vapor pipe 9 and a refrigerant liquid downflow pipe 1.
0, refrigerant circulation path 12 with refrigerant pump 11, dilute liquid pipe 13 with first absorption liquid pump 12, primary intermediate liquid pipe 15 with second absorption liquid pump 14, secondary intermediate liquid pipe 16, concentrated liquid pipe 17 and absorption liquid side pipe 18
A refrigeration cycle is constructed by connecting the pipes.

19 is a water heater attached to the high temperature heat source regenerator 2; 20 is a low temperature fluid supply pipe to the low temperature heat source regenerator 1; 21 is a fuel supply pipe to the high temperature heat source regenerator 2; 22 is a pipe from the evaporator 5. A cold water pipe for taking out cold water for cooling, 23 a three-way valve provided on the low temperature fluid supply pipe 20, and 24 a fuel control valve provided on the fuel supply pipe 21.

25 is a temperature detector that senses the low temperature fluid supply temperature to the low temperature heat source regenerator 1, that is, the main heat source temperature; The chilled water temperature (load fluid temperature) which is the operation start condition is set, and the set temperature is continuously changed in accordance with the main heat source temperature, and the three-way valve 23 and the fuel It is a temperature regulator that sends an output signal to the controller 27 for controlling the opening degree of the control valve 24, and 28 is a temperature detector that senses the temperature of cold water (load fluid), and the signal from the detector is used to control the temperature adjustment. It is sent to the container 26.

Next, the control operation in the embodiment of the present invention will be explained.

(a) Setting the chilled water (load fluid) temperature that is the condition for starting valve operation When the absorption chiller is operating, first, the three-way valve 23 and the fuel control valve 24 are set in the temperature controller 26 according to the signal from the main heat source temperature detector 25. Set the chilled water temperature to start operation.

For example, as shown in Figure 3, the main heat source temperature is 75
℃ or below, the cold water temperature at which the fuel control valve 24 starts to open is 7.5℃, and when the main heat source temperature is 80℃, the cold water temperature at which the fuel control valve 24 starts to open is 8℃. Set the cold water temperature as the starting condition. That is, the condition for starting the operation of the fuel control valve 24 is set according to the relationship (chilled water set temperature) = 0.1 x (main heat source temperature) (FIG. 3).
Further, the cold water (load fluid) temperature, which is a condition for starting the operation of the three-way valve 23, is set to be, for example, 1.5° C. lower than the set temperature for the fuel control valve 24.

(b) Valve opening control Once the cold water (load fluid) temperature, which is the operating start condition for the three-way valve 23 and fuel control valve 24, is set, the three-way valve 23 and fuel control valve 24 are then controlled according to the load. The opening degree is controlled. In other words, when the chilled water temperature rises above the set temperature, a signal from the chilled water temperature detector 28 is sent to the low temperature heat source regenerator 1 of the three-way valve 23 via the temperature regulator 26 and controller 27.
Increase the opening degree to the side and the opening degree of the fuel control valve 24,
Conversely, when the cold water temperature drops, the opening degree is reduced, and when the temperature drops below the set temperature, it is fully closed.

For example, as shown in FIG. 4, when the main heat source temperature is 75° C. or lower (see FIG. 4 a), the cold water setting temperature, which is the condition for starting the operation of the valve, is as described above in the three-way valve 23. 6.0°C, and 7.5°C in the fuel control valve 24, and the opening degree of the three-way valve 23 on the low-temperature heat source regenerator 1 side [hereinafter referred to as the main heat source opening degree]. ] is 0 when the cold water temperature is between 6.0℃ and 7.5℃.
The fuel control valve 24 is proportionally controlled from % to 100%.
[Hereinafter, referred to as auxiliary heat source valve. ] The opening degree is proportionally controlled from 0% to 100% between 7.5°C and 9.0°C. In addition, when the main heat source temperature is 80℃ (see Figure 4b), the cold water set temperature, which is the condition for starting the valve operation, is:
At 6.5℃ at the main heat source valve and at the auxiliary heat source valve
The main heat source valve opening is 0% to 100% when the chilled water temperature is between 6.5℃ and 80℃, and the auxiliary heat source valve opening is between 0% and 100% when the chilled water temperature is between 8.0℃ and 9.5℃.
When the main heat source temperature is 100% proportional control and the main heat source temperature is 85°C (see Figure 4 c), similarly, the chilled water setting temperature is 7.0°C and 8.5°C, respectively, and the main heat source valve opening degree is 7.0°C.
The opening degree of the auxiliary heat source valve is proportionally controlled from 0% to 100% between 8.5°C and 100°C.

As described above, the present invention sets the chilled water (load fluid) temperature at which heat source supply is started in accordance with the main heat source temperature, and uses the chilled water set temperature as a base point to respond to changes in the chilled water temperature, that is, load fluctuations. The opening degree of the main heat source valve and the auxiliary heat source valve is controlled by the temperature controller 26, and the temperature controller 26 continuously changes the cold water set temperature in accordance with changes in the main heat source temperature, in other words, changes in the thermal energy of the main heat source fluid. As is clear from the comparison between FIG. 1 and FIG. 4, in the present invention, the main heat source valve is controlled according to the change in the main heat source temperature, and the heating to the low temperature heat source regenerator 1 is reduced compared to the conventional example. If the main heat source temperature changes without changing the load, that is, the chilled water temperature, for example, if the chilled water temperature remains 9℃ and the main heat source temperature changes from 75℃.
When the temperature changes from 80°C to 85°C, the auxiliary heat source valve opening degree is controlled from 100% to 67% and then to 33% (see Figure 4). This saves on auxiliary heat sources without the need for additional heating.

Although the embodiment has been described with reference to the case where the load fluid is cold water, it goes without saying that the present invention can be implemented using hot water taken out from the water heater 19 as the load fluid.

As described above, the present invention changes the set temperature of the load fluid at which supply of the main heat source and the auxiliary heat source is started in accordance with the temperature of the main heat source, and opens the main heat source valve and the auxiliary heat source valve in accordance with the temperature of the load fluid. It consists of a temperature controller that outputs a signal to control the temperature, and a controller that inputs the signal from the temperature controller to control the opening degree of the main heat source valve or auxiliary heat source valve. Since the supply of the main heat source and auxiliary heat source is controlled by adjusting the operating conditions of the valve with a temperature controller, the main heat source can be used rationally and the auxiliary heat source can be saved using a simple control device, which is useful in practice. be.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional control example, where the broken line shows the opening degree of the main heat source valve and the solid line shows the opening degree control of the auxiliary heat source valve. Fig. 2 is an explanatory diagram of the circuit configuration of the embodiment of the present invention, Fig. 3 is a diagram showing the cold water set temperature which is the operating condition of the valve,
4a, b, and c are diagrams showing control examples of the present invention, in which the broken line shows the opening degree of the main heat source valve, and the solid line shows the opening degree control of the auxiliary heat source valve. 23... Three-way valve, 24... Fuel control valve, 25...
...Main heat source temperature detector, 26...Temperature controller, 27
...Controller, 28...Cold water temperature detector.

Claims (1)

[Claims] 1. In an absorption chiller that uses solar hot water, etc. as the main heat source and combustion gas, etc. as the auxiliary heat source, the main heat source valve controls the supply amount of the main heat source, the auxiliary heat source valve controls the supply amount of the auxiliary heat source, and Changes the load fluid set temperature for starting supply of the heat source and auxiliary heat source according to the temperature of the main heat source, and outputs a signal to control the opening degree of the main heat source valve and the auxiliary heat source valve according to the load fluid temperature. 1. A control device for an absorption refrigerator, comprising: a temperature regulator; and a controller that inputs a signal from the temperature regulator to control the opening degree of a main heat source valve or the opening degree of an auxiliary heat source valve.