JPH01285793A - Latent heat accumulating device - Google Patents

Abstract

PURPOSE:To enable prevention of the occurrence of overcooling by providing a heat pipe the heat absorbing surface of which makes contact with a latent heat accumulating material and the heat dissipating surface of which is projected outwardly of a heat accumulating tank. CONSTITUTION:A latent heat accumulating material 5 the phase change temperature of which is higher than an open air temperature is contained in a container 3 of a heat accumulating tank 2. The temperature of the latent heat accumulating material 5 is increased by an electric heater 6, heat is transferred to the heat absorbing surface of a heat pipe 9 making contact with the partial surface of the latent heat accumulating material 5, and sealed liquid is heated for vaporization. The steam flows in the direction of the heat dissipating surface on the other side of the heat pipe 9, and the steam is cooled and condensed thereat by means of air outside the heat accumulating tank. The heat of steam in the heat pipe 9 is discharged in the open air, and the steam produces liquid which flows to the heat absorbing side of the heat pipe 9. Through repetition of this process, the temperature of the latent heat accumulating material 5 making contact with the heat absorbing surface of the heat pipe 9 can be kept at a value lower than a phase change temperature, overcooling is prevented from occurring, and a phase change can be produced reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a latent heat storage device, and particularly to a heat storage device that prevents supercooling of a latent heat storage material that occurs during heat storage.

(Prior Art) In recent years, heat storage devices have been used that store thermal energy in a heat storage material and extract and use the heat when necessary.

The heat storage material used in this heat storage device is preferably a material that can store a large amount of heat and does not become bulky even if the amount of heat stored is large. From this point of view, for example, hydrated salt (Ca
Cl, 6HtO (melting point 29.9°C), N
a.S! O1,5H,O (melting point 48°C), CH,C0
A latent heat storage material such as 0N a , 3H,0 (melting point 58°C) is used.

That is, according to the above-mentioned type of latent heat storage material, a large amount of heat is absorbed (or released) during a phase change from a liquid phase to a solid phase.
do. Therefore, by using a latent heat storage material, there is an advantage that a large amount of heat can be stored in a small volume.

However, latent heat storage materials have an unfavorable effect on heat storage called supercooling phenomenon. The characteristic diagram shown by the solid line in Figure 3 shows the hydration term (CH, C00N) as a latent heat storage material.
FIG. 3 is a characteristic diagram showing temperature changes with respect to time changes when using a 3H, 0).

As is clear from FIG. 3, when hydrated salt is heated with a heating device to a temperature higher than the phase change temperature, and after reaching the phase change temperature or higher, heating is stopped and the temperature is lowered, the hydration occurs at time tl. Even though the salt reaches a phase change temperature of 58° C., the hydrated salt does not change from the liquid phase to the solid phase at that point, but remains in the liquid phase as the temperature decreases.

That is, 1 g of hydrated salt changes from liquid phase to solid phase.
Although it can absorb 60 Cal of heat per unit, because no phase change occurs, it can only store 0.65 Cal of heat per IgloC temperature change. Therefore, when supercooling occurs, only the amount of heat multiplied by the temperature difference can be stored. This not only leads to a decrease in heat storage capacity, but also requires a large amount of heat storage material, which has the drawback of increasing the size of the heat storage device. Therefore, in order to solve these drawbacks, it is necessary to take measures to reliably prevent overcooling when storing heat in the latent heat storage material.

BACKGROUND ART Conventionally, a latent heat storage device in which a branch pipe is provided in a heat storage tank is known as a heat storage device that prevents overcooling of a latent heat storage material in order to reliably generate a phase change. This latent heat storage device
As shown in the figure.

In the figure, the latent heat storage device ff50 includes a latent heat storage material 51 that causes supercooling, and a heat storage tank 5 filled with the latent heat storage material 51.
2, a branch pipe 53 that communicates with the inside of the heat storage tank 52 and projects outside the heat storage tank 52, and a sealing plug 54 that seals the branch pipe 53. Note that there is also a latent heat storage material 55 inside the branch pipe 53.
is inserted.

In the latent heat storage device 50 having the above configuration, by providing the branch pipe 53 connected to the heat storage tank 52 so as to protrude to the outside, the crystals 55 serving as crystal nuclei remain in the branch pipe 53 even when the heat storage material 51 is heated. The heat storage material 5 undergoes a phase change from the remaining crystals 55.
Conventionally, heat storage materials (hydrated salts (Na, S, 0.

5H, O)), which did not solidify due to supercooling even when cooled by 40°C or more below the melting point, with this method, solidification starts even when the temperature is only 16°C below the melting point, and supercooling is prevented. To prevent.

However, in the above conventional latent heat storage device-1,
This takes advantage of the fact that the heat of the heat storage tank 52 body is difficult to transfer to the branch pipe 53 because the cross-sectional area of the branch pipe 53 is small.
It is essential to reduce the cross-sectional area of 3. but,
The fact that the cross-sectional area of the branch pipe 53 becomes smaller means that the branch pipe 53
Therefore, if the branch pipe 53 is thin, the heat storage material 55 cannot be easily filled into the branch pipe 53, and therefore overcooling cannot be reliably prevented. Furthermore, if the branch pipe 53 is made larger, the device 50 itself becomes larger and has the disadvantage of lacking in practicality.

(Problems to be Solved by the Invention) In this way, in a heat storage device using a conventional latent heat storage material, when the branch pipes are made thinner, it becomes difficult to fill the heat storage material into the branch bones, and overcooling cannot be reliably prevented. There were times when I couldn't do it. Furthermore, when increasing the size with branch pipes, the main body of the heat storage device becomes large, making it unsuitable for practical use.

Does the present invention have the above rate? The purpose of this invention is to provide a latent heat storage device that can reliably cause a phase change in a latent heat storage material and easily prevent overcooling.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the latent heat storage device of the present invention includes a heat storage tank containing a latent heat storage material that causes supercooling, and the latent heat storage material installed in the heat storage tank. a heating means for heating;
A supercooling prevention device that prevents supercooling of the latent heat storage material with a heat pipe having a heat absorption surface in contact with the surface of the latent heat storage material, a heat radiation surface protruding outside the heat storage tank, and cooling fins installed on the heat radiation surface side. It is characterized by comprising the following.

(Function) In the device configured in this way, the heat absorption surface of the heat pipe, which is the supercooling prevention device, contacts the latent heat storage material, and the other heat radiation surface is exposed to the outside air outside the heat storage tank, so that
The heat at the point where the latent heat storage material contacts the heat pipe escapes into the outside air, so when the heat storage material is heated above the phase change temperature so that heat is stored in the heat storage material, only the temperature at the contact area is lowered to the phase change temperature. It is possible to maintain the temperature below, and phase change can be reliably caused without supercooling.

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

FIG. 1 is a sectional view showing the configuration of an embodiment of a latent heat storage device according to the present invention.

In the figure, the heat storage tank 2 of the latent heat storage device 1 is a metal container 3 whose exterior is covered with a insulation layer 4 having good heat insulation properties. C, hydrated salt (Ca Cl , 6 Ht O (melting point 29.9°C\
Na, S, O,, 5H, O (melting point 48'C), CH
,COONa.

A latent heat storage material 5 such as 3H, O (melting point 58° C.) whose phase change temperature (melting point) is higher than the outside temperature is accommodated. '8
An electric heater (for example, a sheathed heater) 6, which is a heating means for heating the latent heat storage material 5, is wound around the vessel 3. This electric heater 6 is connected to the power supply @M via a switch 7.
8 is connected.

Further, the heat storage tank 2 is provided with a penetration part, and a heat pipe 9 of a supercooling prevention device is provided in this penetration part. This heat pipe 9 is a unidirectional heat transfer member having a heat radiation surface at one end and a heat absorption surface at the other end, and the heat absorption surface of the heat vibrator 9 is connected to a part of the surface of the latent heat storage material 5 in the heat storage tank 2. The heat dissipation surface on the other end side protrudes to the outside of the heat storage tank 2 and is placed in the outside air. An lf seal (for example, an O ring, a rubber ring, etc.) is provided between the penetration part of the heat storage tank 2 and the heat pipe 9.

A temperature sensor 11 that senses the temperature of the outside air is provided in the outside air where the heat dissipation surface of the heat pipe 9 is located.1 The temperature information sensed by this temperature sensor 11 is sent to the power supply circuit 8.
This temperature information turns on the switch 12.
and turn the fan 13.

By rotating this fan 13, the heat pipe 9 can be cooled.

The liquid sealed in the heat pipe 9 has a phase change temperature (10'
C-90'C), water (operating temperature 30°C)
C~200'C) or ethyl alcohol (operating temperature o
QC~127°C), etc. may be used.

In addition, although the heat pipe 9 is used here as a heat transfer means serving as a supercooling prevention device, other materials such as bidirectional high thermal conductivity materials (for example, copper and aluminum) can be used.

Next, the operation of an embodiment of the present invention having the above configuration will be described. First, in order to store heat, the switch 7 for heating the electric heater is turned on, the Ml source is supplied from the power supply circuit 8, and the heat storage tank 2
The electric heater 6 wound around the container 3 is energized. By energizing the heater 6, the latent heat storage material 5 in the heat storage M2 is heated, and the temperature of the latent heat storage material 5 increases. Latent heat storage material 5r7>As the temperature rises, heat is transferred to the heat absorption surface of the heat pipe 9 that is in contact with a part of the surface of the second latent heat storage material 5, and the liquid sealed in the heat pipe 9 is heated. It heats up and evaporates. This steam flows toward the heat radiation surface on the other side of the heat pipe 9, where it is cooled and condensed by the air in the heat storage/heat tank/I4F, and the heat of the steam in the heat pipe 9 is transferred to the heated heat storage material 5. It is released into the outside air at a temperature lower than the ambient temperature. The temperature of the steam that has released its heat to the outside air decreases, and it returns to liquid form on the endothermic surface side of the peat pipe 9.

-・Flows.

By repeating the above steps, ZII'? 7 heat storage materials 5 all heat storage materials 5 can be used.

When the outside air temperature around the heat storage tank is high, the temperature sensor 11 is set in advance to a predetermined value (for example, 25'C), and when the outside air temperature becomes higher than that value, the temperature sensor 11 is set to a predetermined value (for example, 25'C). 11 senses the temperature and sends the temperature information to 1
! The heat radiation surface of the heat pipe 9 can be cooled by sending the heat to the source circuit 8, turning on the switch 12, and rotating the heat sink 13. Therefore, by rotating the fan 13, it is possible to compensate for a lack of natural cooling capacity due to an increase in outside air temperature.

Therefore, the latent heat storage material 5 in the heat storage tank 2 is heated by the electric heater 6.
is heated, and the degree of thirst of the latent heat storage material 5 reaches the phase change temperature (
For example, in the case of hydrated salt CH,C00N, 3H,05
8° C.) or higher, the portion of the latent heat storage material 5 that is in contact with the endothermic surface of the heat pipe 9 is always cooled and remains in the surface phase, and does not rise above the phase change temperature. Therefore, even if the latent heat storage material 5 naturally cools after heating and remains in the liquid phase and the temperature decreases, a portion of the latent heat # in the solid phase remains.
The heat material 5 prevents this solid phase portion from becoming a core and causing supercooling, and stores f! It is possible to reliably change all the latent heat storage material 5 within %I#z into a solid phase.

Next, another embodiment of the latent heat storage device according to the present invention will be described. As can be seen from the cross-sectional view showing the structure of another embodiment of the latent heat storage device according to the second aspect of the present invention, the fins 14 are added to the structure of the previous embodiment.

This fin 14 is installed on the heat radiation surface side of the heat pipe 9 that protrudes outside the heat storage tank 2, and the other *a and operation are the same as in the previous embodiment. By providing the fins 14 in this way, the heat radiation ability of the heat radiation surface of the heat pipe 9 can be increased, and the temperature of the latent heat storage material 5 in contact with the heat absorption surface of the heat pipe 9 can be kept lower. , overcooling can be more reliably prevented by simply increasing tI/4.

In addition, the present invention can be implemented with various modifications without departing from the scope.

〔Effect of the invention〕

According to the present invention, the heat absorption surface of the heat transfer means, which is a supercooling prevention device, is brought into contact with a part of the surface of the latent heat storage material, and the heat radiating surface is exposed to the heat storage soluble outside air. material
The part of the pipe welded to the endothermic surface can be kept at a low temperature, reliably preventing overcooling of the latent heat storage material and causing a phase change. Moreover, since overcooling can be prevented with a simple configuration, it is possible to reduce the size of the device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the configuration of one embodiment of the latent heat storage device according to the present invention, FIG. 2 is a cross-sectional view showing the configuration of another example of the latent heat storage device according to the present invention, and FIG. A temperature-time characteristic diagram of a heat storage material, FIG. 4 is a sectional view showing the configuration of a conventional latent heat storage device. 1... Latent heat storage device, 2... Heat storage tank, 3... Container, 4... Heat insulation lil. 5... Latent heat storage material, 6... Electric heater 1 9... Heat pipe, 14... Fin. Agent Patent Attorney Nori Ken Ken Yudo Uji Hiroshi ■ 1g wi Z j prisoner 4-1! ]

Claims (2)

[Claims] (1) A heat storage tank containing a latent heat storage material that causes supercooling;
A heating means for heating the latent heat storage material installed in the heat storage tank, and a heat pipe whose heat absorption surface is in contact with the surface of the latent heat storage material and whose heat radiation surface protrudes outside the heat storage tank are used to supercool the latent heat storage material. A latent heat storage device characterized by comprising a supercooling prevention device for preventing supercooling. (2) The latent heat storage device according to claim 1, characterized in that fins are provided on the heat radiation surface side of the heat transfer means.