JPH0660772B2 - Concentration difference heat storage device and operation method - Google Patents

Description

The present invention relates to a concentration difference heat storage device, and more particularly to a concentration difference heat storage device that improves heat recovery efficiency and is suitable for downsizing a cooling device provided in the device. The present invention relates to a device and an operating method.

[Conventional technology]

For example, as a concentration difference heat storage device used in an absorption refrigerator or the like, the proposal described in JP-A-60-195575 is known. This proposal is constructed as shown in FIG. In the figure, a container 1 is provided with a concentrating / diluting machine 2 and a condensing / evaporating machine 3, and cooling / heating pipes 4 and 5 are provided in each. These act as a condenser 2, a condenser 3, a heating pipe 4, and a cooling pipe 5 during a heat storage operation, and a diluter 2, an evaporator 3, a cooling pipe 4, and a heating pipe 5 during a heat radiation operation.
Acts as. The heat storage liquid storage tank 6 is a container for storing a concentrated liquid and a dilute liquid of the heat storage liquid, respectively, and the refrigerant storage tank 7 is a container for storing a refrigerant. Heat storage liquid storage tank 6 and concentration
Supply side pipes 8 and 9 and a discharge side pipe 1 are provided between the diluter 2 and the diluter 2.
0, 11 are connected to these pipes 8, 9 and 1
A heat exchanger 12 is provided between 0 and 11. Similarly condensed with the refrigerant storage tank 7. Supply side pipes 13 and 14 and discharge side pipes 15 and 16 are connected between the evaporator 3 and
A heat exchanger 17 is provided between the pipes 13, 14 and 15, 16. Pumps 18 and 19 are arranged in the supply side pipes 8 and 13, respectively.

In the conventional concentration difference heat storage device configured as described above, a liquid having a vapor pressure lower than that of the refrigerant is used as the heat storage liquid, and first, at the time of the heat storage operation, the low concentration heat storage liquid is connected to the pipes 8 and 9.
Is introduced into the concentrator 2 by the pump 18 via the heating tube 4
A high temperature liquid is supplied to and heated. The steam generated at this time is introduced into the condenser 2 held at the same pressure as the condenser 2 and condensed. The heat storage liquid condensed by generating steam is returned to the heat storage liquid storage tank 6 again via the pipe lines 10 and 11.
At this time, the low-concentration heat storage liquid introduced into the concentrator 2 has a temperature in a state of being stored in the heat storage liquid storage tank 6,
Usually, it is about 25 ° C. at room temperature. When the heat storage liquid having such a temperature is supplied to the concentrator 2 as it is, it is necessary to raise the temperature until evaporation, that is, to heat the sensible heat by the heating pipe 4.

On the other hand, the heat storage liquid concentrated and returned to the heat storage liquid storage tank 6 is usually 70
Since the temperature is higher than 0 ° C., the return liquid and the supply liquid are heat-exchanged by the heat exchanger 12, so that the supply liquid is heated and the heating amount related to the sensible heat change can be reduced.

Further, at the time of heat radiation operation, the concentrated heat storage liquid described above is introduced into the diluter 2, and the vapor generated by being heated by the heating pipe 5 in the evaporator 3 is absorbed to generate heat and become a low concentration.
In order to cool the heat storage liquid that has generated heat and has risen in temperature, the cooling pipe 4
Coolant is flowing through.

[Problems to be Solved by the Invention]

However, according to the conventional concentration difference heat storage device configured as described above, the heat storage liquid whose temperature has risen to a low concentration during the heat radiation operation returns to the heat storage liquid storage tank 6 via the heat exchanger 12,
The heat of the high-concentration heat storage liquid stored at room temperature is exchanged, and the temperature of the high-concentration heat storage liquid introduced into the diluter 2 is increased.
Therefore, there is a problem that the amount of cooling heat in the diluter 2 increases or the amount of vapor generated in the evaporator 3 decreases. As a result, the cooling equipment capacity must be increased, and if the same cooling equipment capacity is used, the amount of cold heat obtained is reduced.

An object of the present invention is to provide a concentration difference heat storage device and an operating method capable of reducing the amount of cooling heat during a heat radiation operation or increasing the amount of cold water heat with the same amount of cooling heat.

[Means for Solving the Problems]

In order to achieve the above object, the present invention comprises a heat storage liquid concentrating / diluting device and a refrigerant condensing / evaporating device, each of which heats and
From a container in which a cooling pipe is installed, a heat storage liquid storage tank for heat storage liquid and a refrigerant storage tank for refrigerant that are connected to the concentrator / diluter and condenser / evaporator via piping, respectively, and from the heat storage liquid storage tank to the condenser / diluter In a concentration difference heat storage device equipped with a heat exchanger that exchanges heat between the supplied heat storage liquid and the heat storage liquid discharged from the concentrating / diluting device to the heat storage liquid storage tank, heat exchange between the concentrating / diluting device and the heat storage liquid storage tank A bypass pipe that bypasses the heat exchanger is provided in either one of the pipes connected via the heat exchanger, and liquid temperature measuring means is provided at the heat exchanger inlet of each pipe, and the heat storage liquid is set by the set liquid temperature. And a means for switching the flow path to either the heat exchanger or the bypass pipe.

[Action]

According to the above configuration, when it is detected by the liquid temperature measuring means that the temperature of the heat storage liquid in the heat storage liquid storage tank is lower than the temperature of the heat storage liquid discharged from the diluter during the heat radiation operation, the heat storage liquid storage tank stores the heat storage liquid. By switching the introduction flow path to the diluter to the bypass pipe by the switching means and introducing it into the diluter without passing through the heat exchanger, it is possible to supply the heat storage liquid having a high normal temperature and concentration to the diluter at the same temperature. . As a result, the amount of heat for cooling the diluter can be reduced, and if the cooling facility capacity is reduced or the same cooling facility capacity is used, the amount of steam generated in the evaporator can be increased and the cold heat output can be increased. it can. Also, if the temperature of the heat storage liquid in the heat storage liquid storage tank is higher than the temperature of the heat storage liquid discharged from the diluter due to operating conditions or weather conditions, the heat exchanger should be operated in the same manner as during heat storage even during heat dissipation. The temperature of the heat storage liquid introduced into the diluter is lowered.

〔Example〕

An embodiment of the concentration difference heat storage device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, parts that are the same as or equivalent to those in the conventional example shown in FIG. The feature of this embodiment is that the supply side pipes 8 and 9 connecting the heat storage liquid storage tank 6 and the concentrating / diluting device 2 are
A bypass pipe 20 that bypasses the heat exchanger 12 is provided, and the liquid temperature measuring device 2 is provided in each of the supply side pipe 8 and the discharge side pipe 10.
1, 22 are provided, electromagnetic switching valves 23, 24 are provided on the heat exchanger 12 side from the branch point of the bypass pipe 20 of the supply side pipe 8 and this bypass pipe, respectively, and further by the liquid temperature measuring devices 21, 22. Measurement calculator 2 that outputs a signal for opening and closing the solenoid on-off valves 23, 24 according to the detected temperature signal
5 is provided. In this embodiment, the heat exchanger on the refrigerant storage tank 7 side is unnecessary, and the discharge side pipes 10 and 15 and the supply side pipes 9 and 13 are connected by return pipes 26 and 27, respectively. Other structures are similar to those of the conventional example.

Next, the operation of this embodiment will be described with reference to FIGS. For example, in an absorption refrigerator, LiBr is used as the heat storage liquid.
The aqueous solution uses water as the refrigerant, and the heating liquid and the cooling liquid also use water. The system shown in FIG. 2 is used during the heat storage operation. In this case, as described above, the container 1 functions as the condenser 2, the condenser 3, the heating pipe 4, and the cooling pipe 5. The heating liquid having a temperature of about 95 ° C. is supplied to the heating pipe 4, and the cooling liquid having a temperature of about 30 ° C. is supplied to the cooling pipe 5. When the heat storage liquid and the refrigerant are heated or cooled by 5 ° C. by these heating liquid and cooling liquid, respectively, the heating liquid outlet temperature becomes about 90 ° C., the cooling water outlet temperature becomes about 35 ° C., and the heat exchange temperature difference is assumed to be 3 ° C. Then, the condensing temperature is about 87 ° C. and the condensing temperature is about 38 ° C., respectively. To the concentrator 2 of the container 1 satisfying the above conditions, the 55% concentration LiBr aqueous solution was fed from the heat storage liquid storage tank 6 to the pipe 8 and the heat exchanger 1.
2. When introduced through the pipe 9, the heat storage liquid is concentrated to 61.7%, sucked by the pump 18, and part of the heat is stored in the pipe 10.
And most of the other flows through line 26 to line 9,
The heat storage liquid is mixed with the heat storage liquid supplied from the heat storage liquid storage tank 6.
The temperature of the medium having a concentration of 61.7% flowing to the pipe 10 is 87
Since it is ℃, heat is transferred to the heat storage liquid from the heat storage liquid storage tank 6 in the heat exchanger 12, and this heat storage liquid is transferred from 30 ° C. to 76.2.
Raise the temperature to ℃. Therefore, it is not necessary to obtain the amount of heat required for sensible heat change from 30 ° C to 76.2 ° C from the heated water,
Further, since the 61.7% concentration LiBr aqueous solution is cooled to 30 ° C., even if it is discharged into the heat storage liquid storage tank 6, this storage tank 6 is
Can be a room temperature storage tank, and the material of the storage tank 6 can be made inexpensive. Further, the steam generated in the concentrator 2 moves to the condenser 3 and
The water is condensed at ℃ and accumulated in the refrigerant storage tank 7.

Next, the operation at the time of heat radiation operation will be described with reference to FIGS. 3 and 4. In this case, as described above, the container 1 functions as the diluter 2, the evaporator 3, the cooling pipe 4, and the heating pipe 5. By flowing the cooling water through the cooling pipe 4 and the heating water through the heating pipe 5, the operating conditions of the diluter 2 and the evaporator 3 are set.
For example, a LiBr aqueous solution having a concentration of 61.7% and a temperature of 30 ° C. is introduced into the diluter 2, absorbs water vapor generated in the evaporator 3 and is diluted to a concentration of 55%, and the temperature rises at the same time. To about 38 ° C. This heat storage liquid is absorbed by the pump 18, part of which flows to the pipe 9 via the pipe 26, and the other part of which is the pipe 10 and the heat exchanger 1.
2. Return to the heat storage liquid storage tank 6 via the pipe 11. At this time,
As described above, the heat storage liquid discharged from the pipe 10 is
When the temperature is higher than the heat storage liquid supplied to the diluter 2 through the pipes 8 and 9, the liquid temperature measuring devices 21 and 22 shown in FIG.
This is detected by, and the electromagnetic on-off valve 23 is closed and the opening 24 is opened via the measurement calculator 25, and the heat storage liquid is bypassed by the bypass line 2
Let it flow to 0. As a result, since the heat storage liquid on the supply side does not pass through the heat exchanger 12, heat exchange is not performed, and the heat storage liquid is introduced into the diluter 2 as it is at about 30 ° C. Therefore, the amount of cooling heat to the cooling pipe 4 of the diluter 2 can be reduced as compared with the case where the diluter 2 is introduced through the conventional heat exchanger 12. Then, the water generated in the evaporator 3 and deprived of the latent heat is heated to 8 ° C., and cold water having a water temperature of 11 ° C. is obtained from the outlet of the heating pipe 5.
Further, the heat storage liquid discharged from the pipe 10 is
When the temperature is lower than that of the heat storage liquid supplied to the diluter 2 through the same, the electromagnetic opening / closing valve 23 is opened and 24 is closed as in the heat storage operation, so that the heat storage liquids on both the supply side and the discharge side are heat exchangers. 1
The heat storage liquid on the supply side is cooled by performing heat exchange so as to flow through the flow path 2.

The result of the simulation calculation of the above situation is shown in FIG. This figure is a graph showing the relationship between the temperature efficiency Φ of the heat exchanger 12 and the heat recovery rate determined by the heating amount required during the heat storage operation and the cold heat output amount obtained during the heat radiation operation. This temperature efficiency Φ is given by the following equation (1).

Here, T ₁ : high temperature side inlet temperature T ₂ : high temperature side outlet temperature t ₁ : low temperature side inlet temperature As can be seen, as the heat exchange temperature efficiency Φ on the horizontal axis improves, the heat recovery efficiency improves. There is. The solid line shows the case where heat is exchanged through the heat exchanger 12 both during the heat storage operation and the heat radiation operation, and the broken line shows the case where the heat exchanger 12 is not used during the heat radiation operation. From this figure, the heat storage according to the present embodiment is shown. It is clear that the heat recovery efficiency of the device is improved.

According to this embodiment, it is possible to reduce the amount of cooling water supplied to the cooling pipe 4 in the diluter 2 during the heat radiation operation, and it is possible to reduce the capacity of the cooling water manufacturing device such as the cooling water tower. . On the other hand, if the cooling water production apparatus has the same capacity, the cooling amount is improved, and as a result, the amount of cold water heat obtained in the heating pipe 5 can be increased.

〔The invention's effect〕

As described above, according to the present invention, since the bypass conduit of the heat exchanger provided in the concentration difference heat storage device is provided, the temperature of the heat storage liquid supplied to the concentrator during the heat storage operation is increased to heat the concentrator. It is possible to reduce the amount of heat, reduce the amount of cooling heat of the diluter or increase the amount of cold heat output without using a heat exchanger depending on the operating conditions during the heat radiation operation, and energy saving is achieved.

[Brief description of drawings]

FIG. 1 is a piping system diagram of an embodiment of the concentration difference heat storage device according to the present invention, and FIGS. 2 and 3 are piping system diagrams at the time of heat storage operation and heat release operation of FIG. 1, FIG. 4 and FIG. FIG. 5 is a graph showing the relationship between the operating state of the heat storage device and the temperature efficiency of the heat exchanger and the heat recovery rate, respectively, and FIG. 6 is a piping system diagram showing an example of a conventional concentration difference heat storage device. Is. 1 ... Container, 2 ... Concentrator / diluter, 3 ... Condenser / evaporator, 4,5 ... Heating / cooler, 6 ... Heat storage liquid storage tank, 7 ... Refrigerant storage tank, 8, 9, 10, 11, 13, 14, 15, 16, 2
6, 27 ... Piping, 12, 17 ... Heat exchanger, 18, 19 ... Bumps, 20 ... Bypass piping 21, 22
... Liquid temperature measuring device, 23, 24 ... Electromagnetic on-off valve, 25 ... Measurement arithmetic unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuya Ehara 4026 Kuji Town, Hitachi City, Ibaraki Prefecture, Hitachi Research Laboratory Ltd. Hitachi, Ltd. (56) References JP 62-56751 (JP, A) JP 63-49670 (JP, A)

Claims (2)

[Claims] 1. A container comprising a condensing / diluting device for a heat storage liquid and a condensing / evaporating device for a refrigerant, each having a heating / cooling pipe, and each of the concentrating / diluting device and the condensing / evaporating device. A heat storage liquid storage tank of the heat storage liquid and a refrigerant storage tank of a refrigerant connected via a pipe, a heat storage liquid supplied from the heat storage liquid storage tank to the concentrator / diluter, and discharged from the concentrator / diluter to the heat storage liquid tank. In a concentration difference heat storage device comprising a heat exchanger for exchanging heat with the heat storage liquid, the heat is stored in either one of the pipes connecting the concentrator / diluter and the heat storage liquid storage tank via the heat exchanger. A concentration difference heat storage device, characterized in that a bypass pipe bypassing the exchanger is provided, and a liquid temperature measuring means is provided at the heat exchanger inlet of each pipe. 2. A heat storage liquid inlet temperature of each of the heat exchangers is measured by a liquid temperature measuring means, heat is exchanged through the heat exchanger when the heat storage liquid is concentrated, and from a heat storage liquid storage tank when the dilution operation is performed. When the temperature of the heat storage liquid flowing into the heat exchanger is higher than the temperature of the heat storage liquid discharged from the concentrating / diluting device to the heat exchanger, the heat storage liquid is bypassed to either one of the heat exchangers. A method for operating a concentration difference heat storage device, which is characterized in that it is distributed through a pipe.