JPH04306465A - Absorption freezer - Google Patents

Abstract

PURPOSE:To prevent the damage of a device even when the interior of a room is in a no-load state by a method wherein during the stop of cooling operation, operation of a solution circulating pump, a cooling fan, and a refrigerating circulating pump is turned OFF at a cold water freezing temperature and turned ON at a freezing temperature or higher and the above is repeated until the temperature of a reproducer is reduced to a value lower than a given value. CONSTITUTION:When, after the stop of cooling operation, a cold water temperature is reduced to 1 deg.C, operation of a solution circulating pump 10, a cooling fan 11, and a refrigerant circulating pump 13 is switched from ON to OFF. Even when a load is not applied, a cold water temperature is increases by the generation of heat of a cold hot water pump 12. When the cold water temperature attains to 4 deg.C, operation of the solution circulating pump 10, the cooling fan 11, and the refrigerant circulating pump 13 is brought into an ON-state again. During ON-operation, the temperature of a high temperature reproducer 1 is reduced and until it attains to 105 deg.C, the ON and OFF cycle of the solution circulating pump 10, the cooling fan 11, and the refrigerant circulating pump 13 is repeated. Thus, a cold water temperature is held at 1-4 deg.C and no freezing occurs until completion of dilution. This constitution prevents breakage of a device owing to freezing of cold water.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption liquid dilution operation, and more particularly to an absorption refrigerator equipped with a control device suitable for preventing chilled water from freezing when cooling operation is stopped.

0002

2. Description of the Related Art FIG. 4 shows a conventional absorption refrigerating machine, in this case an air-cooled dual-effect absorption chiller/heater. A high-temperature regenerator 1 that heats a dilute solution, a separator 2 that separates refrigerant vapor generated from the high-temperature regenerator 1 and an intermediate concentrated solution, and a low-temperature regenerator that exchanges heat between the intermediate concentrated solution and refrigerant vapor to form a concentrated solution. 3, a condenser 4 that condenses refrigerant vapor into a refrigerant liquid, an evaporator 6 that sprays the refrigerant liquid onto the heat transfer tube 6A and cools the cold water in the heat transfer tube 6A with the heat of vaporization of the refrigerant liquid, and the evaporator 6. an absorber 7 that absorbs evaporated refrigerant vapor into a concentrated solution and dilutes it into a dilute solution; a high-temperature heat exchanger 8 that exchanges heat between the intermediate concentrated solution and the dilute solution; and a low-temperature heat exchanger that exchanges heat between the dilute solution and the concentrated solution. A solution circulation pump 10 that pumps the dilute solution to the high temperature regenerator 1 via the vessel 9, a cooling fan 11 that cools the absorber 7 and the condenser 4, a cold/hot water pump 12 that circulates cold water, and the evaporator 6. This configuration includes a refrigerant circulation pump 13 that circulates refrigerant liquid. When the cooling operation is stopped, a dilution operation is performed to prevent the absorption liquid (concentrated solution) from crystallizing, but if there is no load indoors, there is a risk that the cold water will freeze due to the remaining capacity during the dilution operation. That is, as shown in FIG. 5, a solution circulation pump,
If the cooling fan and refrigerant circulation pump are operated until the temperature of the high-temperature regenerator drops to approximately 105°C, the temperature of the chilled water will not reach the freezing temperature when there is a load, but it will reach the freezing temperature when there is no load. to freeze. In particular, with the downsizing of equipment and air cooling, the absorption liquid is inevitably operated at a high concentration, and when the cooling operation is stopped, the absorption liquid will crystallize at this concentration, so it is necessary to perform dilution operation to lower the concentration. be. To prevent freezing by using residual capacity, measures are generally taken such as operating the cold/hot water pump and applying a load, but if there is no load, the effect of completely preventing freezing cannot be obtained, leading to freezing. .

0003

[Problems to be Solved by the Invention] Conventional absorption chillers have the problem that if there is no load in the room when cooling operation is stopped, the remaining capacity will cause the chilled water to freeze even if dilution operation is performed, causing damage to the equipment. was there.

An object of the present invention is to provide an absorption refrigerator equipped with a control device that can prevent damage to equipment due to freezing of cold water even when there is no load in the room when cooling operation is stopped.

[0005]

[Means for Solving the Problems] In order to achieve the above object, an absorption refrigerator according to the present invention includes a regenerator for heating a dilute solution, and a separator for separating refrigerant vapor generated from the regenerator from a concentrated solution. , a condenser that condenses refrigerant vapor into refrigerant liquid, an evaporator that spreads refrigerant liquid onto heat transfer tubes and uses the heat of vaporization of the refrigerant liquid to cool the cold water in the heat transfer tubes, and converts the refrigerant vapor evaporated in the evaporator into a concentrated solution. An absorber that absorbs water and dilutes it into a dilute solution, a solution circulation pump that pumps the dilute solution to the regenerator via a heat exchanger that exchanges heat between the dilute solution and the concentrated solution, and a cooling system that cools the absorber and condenser. In an absorption chiller consisting of a fan, a hot/cold water pump that circulates chilled water, and a refrigerant circulation pump that circulates refrigerant liquid to the evaporator, when the cooling operation is stopped, the operation of the solution circulation pump, cooling fan, and refrigerant circulation pump is stopped to freeze the chilled water. The regenerator is configured to include a control device that turns off at temperature and turns on at temperatures above freezing temperature, and repeatedly turns on and off to dilute the concentrated solution until the temperature of the regenerator drops to a predetermined temperature.

[0006] A regenerator that heats the dilute solution; a separator that separates the refrigerant vapor generated from the regenerator and the concentrated solution;
A condenser that condenses refrigerant vapor into refrigerant liquid, an evaporator that spreads refrigerant liquid onto heat transfer tubes and uses the heat of vaporization of the refrigerant liquid to cool the cold water in the heat transfer tubes, and absorbs the refrigerant vapor evaporated in the evaporator into a concentrated solution. an absorber for diluting the solution into a dilute solution; a solution circulation pump for pumping the dilute solution to a regenerator via a heat exchanger for exchanging heat between the dilute solution and the concentrated solution; a cooling fan for cooling the absorber and the condenser; In an absorption refrigerator consisting of a cold/hot water pump that circulates cold water and a refrigerant circulation pump that circulates refrigerant liquid to the evaporator, when cooling operation is stopped, the solution circulation pump and refrigerant circulation pump are continuously operated until the regenerator cools to a predetermined temperature. A configuration may also be adopted in which a control device is provided that turns off the operation of the cold water pump when the cold water reaches the freezing temperature and turns it on when the cold water reaches the freezing temperature and repeatedly turns on and off to dilute the concentrated solution.

[0007]

[Operation] According to the absorption refrigerator of the present invention, after the cooling operation is stopped, the control device inputs the chilled water outlet temperature signal, the regenerator temperature signal, and the cooling operation stop signal, and the temperature of the chilled water is frozen. When the temperature reaches the temperature, the operation of the solution circulation pump, cooling fan, and refrigerant circulation pump is switched from on to off. Even when there is no load, the temperature of chilled water rises due to heat generated by the chilled/hot water pump. When the chilled water temperature reaches the freezing temperature or higher, the solution circulation pump, cooling fan, and refrigerant circulation pump are turned on again. During this time, the temperature of the regenerator gradually decreases, and the solution circulation pump, cooling fan, and refrigerant circulation pump are repeatedly turned on and off until the temperature drops to a predetermined temperature. Therefore, the cold water temperature is maintained above the freezing temperature.

[0008]

[Embodiment] An embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, a high temperature regenerator (regenerator)
1 has a combustion chamber inside, absorbs refrigerant, heats a diluted solution, and generates refrigerant vapor from the diluted solution. The separator 2 evaporates the refrigerant vapor and separates the refrigerant vapor from the intermediate concentrated solution. Low temperature regenerator (regenerator)
3 reheats the intermediate concentrated solution whose temperature has been lowered by the high temperature heat exchanger (heat exchanger) 8 and the refrigerant vapor coming from the separator 2;
Refrigerant vapor is further generated from the intermediate concentrated solution to form a concentrated solution, and the refrigerant vapor coming from the separator 2 is condensed to form a refrigerant liquid. The condenser 4 cools and liquefies the refrigerant vapor generated in the low-temperature regenerator 3 with the cooling water flowing through the cooling pipe 5 to form a refrigerant liquid. The evaporator 6 is provided with a heat transfer tube 6A through which cold water to be cooled flows, and the refrigerant liquid coming from the condenser 4 is sprayed onto the heat transfer tube 6A, and the heat of vaporization when the refrigerant liquid turns into refrigerant vapor is utilized. Cooling cold water. The absorber 7 is sprayed with a concentrated solution coming from the low temperature regenerator 3, and this concentrated solution absorbs the refrigerant vapor vaporized in the evaporator 6. A high vacuum is ensured in the evaporator 6 by the absorption action of the absorber 7, so that the refrigerant liquid spread on the heat transfer tubes 6A in the evaporator 6 can be immediately evaporated. The high-temperature heat exchanger 8 exchanges heat between a high-temperature intermediate concentrated solution and a low-temperature dilute solution, and the low-temperature heat exchanger 9 exchanges heat between a high-temperature concentrated solution and a low-temperature dilute solution. In order to improve heat exchange efficiency, the heat exchanger is installed in two stages. The solution circulation pump 10 is provided to circulate a dilute solution that has absorbed refrigerant vapor, and also includes a cooling fan 11 for cooling the absorber 7 and the condenser 4, a cold/hot water pump 12 for circulating cold water, and an evaporator. 6 is provided with a refrigerant circulation pump 13 that circulates refrigerant liquid. Then, thermometers 15 and 16 are provided to detect the outlet temperature of the chilled water and the temperature of the high-temperature regenerator 1, and the respective temperature signals and a cooling operation stop signal are inputted, and the outlet temperature of the chilled water is set to a freezing temperature of, for example, 1°C. When this happens, the operation of the solution circulation pump 10, cooling fan 11, and refrigerant circulation pump 13 is turned off, and when the temperature exceeds the freezing temperature of, for example, 4°C, the operation of the solution circulation pump 10, cooling fan 11, and refrigerant circulation pump 13 is turned on. The configuration includes a control device 20 that repeats on/off operations until the temperature of the high temperature regenerator 1 drops to a predetermined temperature of 105° C., for example.

The control device 20 also includes a solution circulation pump 10.
The refrigerant circulation pump 13 is continuously operated until the temperature of the high-temperature regenerator 1 drops to, for example, 105°C, and the operation of only the cooling fan 11 is turned off when the outlet temperature of the cold water reaches a freezing temperature of, for example, 1°C. It may be configured to turn on when the temperature exceeds the freezing temperature of , and repeat this on/off operation until the temperature of the high temperature regenerator 1 drops to, for example, 105°C.

Next, the operation of this embodiment will be explained with reference to FIG. After the cooling operation is stopped, when the temperature of the cold water reaches 1° C., the operation of the solution circulation pump, cooling fan, and refrigerant circulation pump is switched from ON to OFF. Even when there is no load, the temperature of the cold water rises as shown in the figure due to heat generation from the cold/hot water pump. When the chilled water temperature reaches 4° C., the solution circulation pump, cooling fan, and refrigerant circulation pump are turned on again. During this time, the temperature of the high temperature regenerator gradually decreases, and ON/OFF cycles of the solution circulation pump, cooling fan, and refrigerant circulation pump are repeated until the temperature reaches 105°C. Therefore, the temperature of the cold water is maintained between 1 and 4° C. and does not freeze until the dilution is completed. In addition, as shown in Figure 3, the solution circulation pump and refrigerant circulation pump are operated at a temperature of 10
The cooling fan is operated continuously until the temperature drops to 5℃, and the cooling fan is turned off when the chilled water temperature reaches the freezing temperature of 1℃, and turned on when the chilled water temperature reaches the freezing temperature of 4℃.This ON/OFF operation is controlled by the high temperature regenerator. The same effect as described above can be obtained even if the temperature is repeated until the temperature drops to 105°C. Since the solution circulation pump and the refrigerant circulation pump are continuously operated, the concentration of the absorption liquid after dilution is further diluted, resulting in a large dilution effect.

[0012] The control temperatures of the chilled water and the regenerator are representative values and are not limited to the above-mentioned temperatures. In addition, although the embodiment has been described with respect to an air-cooled absorption refrigerator, it is not limited to air-cooled absorption refrigerators; by using a cooling fan as a cooling water pump in a water-cooled absorption refrigerator, the solution can be diluted without freezing the cold water. It can be performed.

[0013]

[Effects of the Invention] According to the absorption refrigerator of the present invention, even if there is no load indoors when cooling operation is stopped, cold water is prevented from freezing due to the remaining capacity after dilution operation of a concentrated solution, and equipment damage due to freezing of cold water is prevented. be able to.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of this embodiment.

FIG. 3 is a diagram illustrating the operation of another embodiment.

FIG. 4 is a diagram showing a conventional technique.

FIG. 5 is a diagram illustrating the operation of the conventional technology.

[Explanation of symbols]

1 High temperature regenerator 2 Separator 3 Low temperature regenerator 4 Condenser 6 Evaporator 8 High temperature heat exchanger (heat exchanger) 9 Low temperature heat exchanger (heat exchanger) 10 Solution circulation pump 11 Cooling fan 12 Cold and hot water pump 13 Refrigerant circulation pump 20 Control device

Claims (2)

[Claims] Claim 1: A regenerator for heating a dilute solution; a separator for separating refrigerant vapor generated from the regenerator and a concentrated solution;
a condenser that condenses the refrigerant vapor into a refrigerant liquid; an evaporator that sprays the refrigerant liquid onto the heat transfer tube and cools the cold water in the heat transfer tube with the heat of vaporization of the refrigerant liquid; and the refrigerant vapor evaporated in the evaporator. an absorber that absorbs the solution into the concentrated solution and dilutes it into the dilute solution; a solution circulation pump that pumps the dilute solution to the regenerator via a heat exchanger that exchanges heat between the dilute solution and the concentrated solution;
In an absorption refrigerator comprising a cooling fan that cools the absorber and the condenser, a cold/hot water pump that circulates the cold water, and a refrigerant circulation pump that circulates refrigerant liquid to the evaporator, when the cooling operation is stopped, the solution circulation The operations of the pump, the cooling fan, and the refrigerant circulation pump are turned off at the freezing temperature of the cold water and turned on at or above the freezing temperature, and this on and off is repeated until the temperature of the regenerator drops to a predetermined temperature. An absorption refrigerator characterized by being equipped with a control device for dilution. 2. A regenerator that heats the dilute solution; a separator that separates the refrigerant vapor generated from the regenerator and the concentrated solution;
a condenser that condenses the refrigerant vapor into a refrigerant liquid; an evaporator that sprays the refrigerant liquid onto the heat transfer tube and cools the cold water in the heat transfer tube with the heat of vaporization of the refrigerant liquid; and the refrigerant vapor evaporated in the evaporator. an absorber that absorbs the solution into the concentrated solution and dilutes it into the dilute solution; a solution circulation pump that pumps the dilute solution to the regenerator via a heat exchanger that exchanges heat between the dilute solution and the concentrated solution;
In an absorption refrigerator comprising a cooling fan that cools the absorber and the condenser, a cold/hot water pump that circulates the cold water, and a refrigerant circulation pump that circulates refrigerant liquid to the evaporator, when the cooling operation is stopped, the solution circulation The pump and the refrigerant circulation pump are continuously operated until the temperature of the regenerator drops to a predetermined temperature, and the operation of only the cooling fan is turned off at the freezing temperature of the cold water and turned on at or above the freezing temperature, and this on/off is performed. An absorption refrigerator comprising a control device that repeatedly dilutes the concentrated solution.