JPS63197882A - Method for breaking over-cooled condition of hydride latent heat accumulative material - Google Patents

Abstract

PURPOSE:To provide easy sure discharging of heat from an apparatus at any time by a method wherein a hydride type latent heat accumulative material enclosed in a container having an outer and an inner communication passage is heated and thermally accumulated, thereafter the communication passage is humidified when heat is required so as to break an over-cooled condition of the thermal accumulative material. CONSTITUTION:A thermal accumulative device 1 is comprised of a container 2, a thermal accumulative material 3 and a communication part 4 filled with capillary pipes 5. The thermal accumulative material 3 is composed of hydride-type thermal accumulative material and the capillary pies 5 are composed of fibrous material, continuous bubble material or sintered material. Then, the thermal accumulative device 1 is heated. After the thermal accumulative material 3 is sufficiently melted, it is cooled down to a room temperature, resulting in providing an over-cooled condition of the thermal accumulative material 3. In order to take out heat from the device, it is satisfactory to humidify the capillary tubes 5 arranged in the communication part 4. In case that even if the over-cooled condition is not broken under humidified condition, the capillary tubes 5 may undergo physical action. With this arrangement, it is possible to take out heat from the thermal accumulation device easily and surely at any time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the field of utilizing thermal energy storage devices capable of storing thermal energy in a supercooled state and extracting the stored thermal energy when required.

BACKGROUND OF THE INVENTION Conventionally, hydrated latent heat storage materials (hereinafter referred to as heat storage materials) that utilize latent heat have a large amount of heat storage per unit weight. Since it has advantages such as being able to output a constant temperature, attempts have been made to use it in cordless personal warming devices, heat retention devices, and heating devices. However, most conventional heat storage devices have attempted to use heat storage materials that prevent supercooling. That is, the heat storage material is of a type that starts releasing heat at the same time as heating (heat storage) is completed. Therefore, it was not possible to dissipate heat when necessary, and its uses were limited.

However, recently attempts have been made to utilize the supercooling phenomenon to extract heat from the heat storage material at any time. That is, JP-A No. 61-14283 describes a stable heat storage composition capable of supercooling, which includes a heat storage material and hydroxypropylated guar gum as essential components. In this publication, a heat storage material composition is placed in a transparent thick-walled glass bottle with a screw cap and supercooled, and when heat is required, seed crystals are added or stimulation is applied with a pointed metal rod to achieve supercooling. It shows a means of collapsing and extracting heat. This method is considered to be effective for large-scale heat storage devices such as those used in the hot water supply field. However, as a heat storage body used in a small heat storage device, such as a body warming device, a glass pin with a screw cap gives a strange feeling when attached to the front body. Therefore, it is necessary to seal the heat storage material in a laminate film as used in conventional heat storage bodies that prevent overcooling. However, when the heat storage material is sealed in a laminate film, the supercooled state does not collapse even if stimulation is applied from the outside, and heat cannot be extracted from the heat storage material. Therefore, it is necessary to directly stimulate the heat storage material inside the container to break the supercooled state. For this purpose, it is conceivable to attach a mouth with a screw cap to the container. However, in the case of such a heat storage body, there is a concern that the heat storage material may leak out and contaminate the surrounding area when the container opening is opened and closed. In addition, stimulating the heat storage material directly with a metal rod with a pointed tip may result in a large amount of heat storage material adhering to the metal rod. It required removal, etc., and was troublesome to handle.

Further, Japanese Patent Application Laid-Open No. 61-22194 describes a thermal energy storage device comprising an energy storage material and a stimulator. This publication describes a configuration in which a stimulating body made of a seed crystal is brought into physical contact with an energy storage object in a supercooled state, thereby destroying the supercooling and extracting thermal energy. However, this configuration also has practical problems when used as a small heat storage device. That is, thermal isolation is required to prevent the seed crystal from melting due to heat being applied to the seed crystal during heating (heat storage). However, when the device is small, this thermal isolation is difficult, and even if it is possible, the device becomes bulky. Furthermore, it is difficult to reliably thermally isolate the seed crystal from external stimulation when moving a cell phone or the like or from heating under various environments.

Problems to be Solved by the Invention The present invention attempts to solve the problems with the heat storage body. In other words, when a heat storage body capable of supercooling is used in a thermal energy storage device, supercooling can be conveniently and easily destroyed and heat can be extracted, and the heat storage material can leak and contaminate the surrounding area. This is to ensure that this does not occur.

Means for Solving the Problems In the present invention, in order to solve the above problems, the heat storage device has the following configuration. That is, the heat storage material is enclosed in a container. This container is provided with a communication portion that communicates with the inside and outside of the container, and is provided with a simple stopper such as a capillary body to prevent the heat storage material from leaking from this communication portion. In the heat storage device having this configuration, after storing heat, the communication portion is humidified when the heat storage device is brought into a supercooled state and heat is required.

Function: According to the present invention, the supercooled state can be reliably and safely destroyed by the method described above. That is, since the supercooled heat storage body is sealed in a container, the supercooled state does not collapse easily, although the reason is unclear.

However, in the configuration of the present invention, by humidifying the connecting portion, the supercooled state is easily broken down and heat can be extracted. This is not certain, but it can be thought of as follows. That is, in the communication portion of the container, the capillary body and the like communicate between the inside and the outside of the container, so that the heat storage material oozes out to the outside of the container through the capillary body and the like.

After releasing heat, heat storage material crystals remain attached. When heated in this state to store heat, the heat storage material inside the container absorbs heat and melts. On the other hand, the heat storage material crystals attached to the capillary body or the like outside the connection part no longer melt because the crystal water evaporates and becomes anhydrous salt. The container is therefore sealed and covered with anhydrous salt. In this state, it's outside! Even if a stimulus is applied, the supercooled state of the heat storage material no longer collapses.

When humidified in this state, the anhydrous salt hydrates and becomes the same crystalline heat storage material as the original heat storage material. This heat storage material becomes a seed crystal, and the supercooled state of the heat storage material in contact with the anhydrous salt collapses, crystallization occurs, and latent heat is released. This crystallization propagates throughout the heat storage material. Further, even if humidification is performed, the supercooled state may not collapse. This is thought to be because the hydrate dissolves in water and no seed crystals are generated. However, in this case, if the communicating portion is stimulated from the outside, the supercooled state will easily collapse. It is further useful if this stimulation is performed by seed crystals.

Examples Examples of the present invention will be described below. The figure shows a heat storage device 1 used in the method of the invention. This heat storage device 1 includes a container 2, a heat storage material 3 sealed in the container 2, and a container 2.
It is composed of a communication section 4 provided in the. In addition, in order to prevent the heat storage material 3 from leaking beyond the communication part 4,
is filled with capillary body 5.

Each element will be explained below. The container 2 is made of a material that is non-reactive and incompatible with the heat storage material 3. In particular, when used in a heating device, it is preferable to use an aluminum laminate film because flexibility is required. The heat storage material 3 is a hydrated hook-shaped heat storage material such as calcium chloride hexahydrate, sodium sulfate decahydrate, sodium thiosulfate pentahydrate, and sodium acetate trihydrate, and may contain thickeners, stabilizers, or It is a mixture of thermally conductive substances, etc. The capillary body 5 is a fibrous body made of a material that is non-reactive and incompatible with the heat storage material 3 (for example, natural fibers such as cotton and cellulose, synthetic fibers such as polyester, acrylic, nylon, and aromatic polyamide). Thread-shaped bodies, woven or non-woven fabrics, thin metal wires made of stainless steel, copper, etc.) Open-celled bodies (e.g., polyurethane, various types of open-celled nidistomers, metal foams)
Alternatively, it is made of a sintered body having open cells (for example, a polyethylene porous sintered body or porous ceramics), and is attached to the container 2. A communication portion 4 is thereby formed. One end is attached to the outside of the container 2 so that the other end can come into contact with the heat storage material inside the container. By coming into contact with the heat storage material 3, the capillary body 4 sucks up the heat storage material 3, and the entire capillary body 4 becomes immersed in the heat storage material 3.

When the temperature rises during heat storage and the internal pressure of the container increases, the heat storage material 3 inside the container 2 may leak out through the capillary body 4. It is necessary to design the capillary body so that there is little leakage of material.

The heat storage device 1 having the above configuration is heated (heat stored). After the heat storage material 3 is sufficiently melted and cooled to room temperature, the heat storage material 3 is brought into a supercooled state, and anhydrous salt is attached to the outside 5a of the capillary body. In this state, although the reason is not clear, the supercooled state does not collapse even if stress is applied to the heat storage device 1, such as impact, bending, or pressure.

In order to extract heat, a capillary body 5 provided in the communication portion 4 is used.
You just need to humidify it. As a humidifying method, it may be wetted with water or exposed to steam. As a result, collapse of the supercooled state easily occurs. The reason for this is not clear, but it is thought that the anhydrous salt attached to the outside 5a of the capillary body hydrates during humidification, becomes a seed crystal, and destroys the supercooled state of the heat storage material inside 5b of the capillary body. . The collapse of this supercooled state propagates and spreads throughout the heat storage device. By breaking down this supercooled state, latent heat can be extracted.

Further, even if humidification is performed, the supercooled state may not collapse.

In this case, physical stimulation may be applied to the capillary body 5 after humidification. In particular, the supercooled state easily collapses when stimulated with an Iil intense body to which seed crystals of heat storage material are attached.

Specific examples will be shown below.

Example 1 A container was made by heat-sealing two aluminum laminate films on three sides. At this time, a Q2J2r polyester thread is inserted in one place to form a communication part that communicates the inside and outside of the container. Sodium acetate trihydrate was sealed as a heat storage material in this container to obtain a heat storage device. When this heat storage device is heated to store heat at 90° C. and then cooled, a supercooled product can be easily obtained. At this time, anhydrous sodium acetate, which is the anhydrous form of sodium acetate trihydrate, which has oozed out to the outside due to the capillary action of the polyester thread, is attached and solidified on the outside of the communication portion. In this state, no matter how much external transport was applied, the supercooling did not collapse. In order to extract heat, the supercooled state was easily broken when the anhydride was stimulated with a pine needle whose tip had been wetted with water.

Example 2 In the heat storage device of Example 1, when the anhydride was exposed to steam, the supercooled state easily collapsed.

Example 3 In the heat storage device of Example 1, when the anhydride was wetted with tap water, the supercooled state did not collapse. After this, the supercooled state was easily broken down by washing it with water and lightly stimulating it with a zelkova tree with deposited crystals attached.

Effects of the Invention As described above, the method of the present invention has the following effects. That is, according to the present invention, by humidifying a part of the connecting portion of the heat storage device that is in a supercooled state, the supercooled state can be easily broken down and heat can be removed.

Therefore, by using the method of the present invention, heat can be easily and reliably extracted from the heat storage device at any time.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a sectional view of a heat storage device according to an embodiment of the present invention. 1... Heat storage device, 2... Container, 3...
...Heat storage material, 4...Connection part, 5...
・Capillary body.

Claims (5)

[Claims] (1) A hydrated latent heat storage material that can be supercooled, changes its phase from a liquid to a solid and releases latent heat when stimulated, is sealed in a container that has a communication part that communicates with the inside and outside, and the hydrated latent heat storage material is heated. A method for breaking down the supercooled state of a hydrated latent heat storage material, which humidifies the communication portion when heat is required after storing heat. (2) A method for disrupting the supercooled state of a hydrated latent heat storage material according to claim 1, wherein the communicating portion is wetted with water as a method for humidifying the communicating portion. (3) A method for breaking down the supercooled state of the hydrated latent heat storage material according to claim 1, in which the communicating portion is exposed to water vapor as a method of humidifying the communicating portion. (4) A method for breaking the supercooled state of a hydrated latent heat storage material according to claim 1, wherein the communication portion communicating between the inside and outside is a capillary body. (5) A method for breaking the supercooled state of a hydrated latent heat storage material according to claim 1, wherein the hydrated heat storage material is sodium acetate trihydrate.