JP3857781B2 - Heat storage device capable of controlling heat dissipation and heat dissipation control method for heat storage device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat release control method for a latent heat storage material used for heating a building or the like.
[0002]
[Prior art]
Conditions to be provided as a heat storage material include a large amount of heat storage, heat storage and release at a predetermined temperature level, long-term stability, low cost, no toxicity, no corrosiveness, etc. Is mentioned.
[0003]
Phase change salt hydrates are best studied as satisfying these conditions, but sodium sulfate 10 hydrate, disodium hydrogen phosphate 12 hydrate, sodium acetate trihydrate, etc. are representative. Some have already been put to practical use. Although these salt hydrates have a large calorific value accompanying phase change and have an appropriate phase change temperature, they are all characterized by large supercooling. This large supercooling is considered to be impractical in that the temperature drops too much before reaching heat dissipation, and thus has been regarded as a drawback of salt hydrates so far and the search for supercooling inhibitors has been prolonged. I came.
[0004]
However, this large amount of supercooling is advantageous in that it is possible to select the heat release time, and a few proposals have been made for the purpose of long-term heat storage. For example, it has long been proposed to add a seed crystal when it is desired to dissipate heat. This method can provide reliable heat dissipation at any point of time, but the composition can be changed by repeatedly adding seed crystals, the system can be opened by the addition operation, moisture can evaporate, and the addition operation can be complicated. There were problems such as being impractical.
[0005]
In addition, a method of crystallizing an aqueous solution of sodium acetate trihydrate by inserting an electrode and applying a voltage between the electrodes has been proposed. However, this method also has problems such as the possibility of elution of the electrode material, the possibility of gas generation due to energization, and the limit of repeated use.
[0006]
[Problems to be solved by the invention]
The present invention seeks to solve the problems of the prior art described above. That is, the present invention is a method for controlling the timing of heat release from a supercooled state of a heat storage material mainly composed of salt hydrate, does not cause a change in the composition of the heat storage material, is stable to a long-term cycle, and is complicated to operate. An object of the present invention is to provide a method that is not, and to provide a heat storage device that enables the method.
[0007]
[Means for Solving the Problems]
That is, the present invention is a heat storage device in which a container is filled with a heat storage material containing a salt hydrate, and (A) a seed crystal portion having a cooling or cooling device, (B) a heating device or heating and A switch portion having a cooling device and capable of heating operation or heating and cooling operation; (C) a main body portion having a heating device and capable of storing and releasing heat; and three adjacent portions , and the shape of the one container is A heat storage device capable of controlling heat release, characterized by being cylindrical, coiled, or flat , and (A) crystal propagation from the seed crystal portion to the main body portion (C) for the heat storage device ( B) The present invention relates to a heat release control method for a heat storage device using a heat storage material containing a salt hydrate, which is controlled by heating and heating stop operation or heating and cooling operation of a switch portion.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
The heat storage material of this invention contains the salt hydrate which exhibits a solid-liquid phase change by heating and cooling. The heat storage material is usually used by being filled in a container, and is preferably used by being filled in a container having no moisture permeability. The shape of the container is any one of a cylindrical shape, a coil shape, and a flat plate shape. When used by being embedded in the floor, it is preferable to have sufficient strength to withstand the load.
[0009]
Examples of the salt hydrate include sodium sulfate 10 hydrate, disodium hydrogen phosphate 12 hydrate, sodium acetate trihydrate, calcium chloride hexahydrate, calcium nitrate tetrahydrate, and the like. In the case of anharmonic salt hydrates, it is preferable to add a small excess of water and a solid-liquid separation inhibitor in order to avoid the formation of low-order hydrates. The small excess of water is selected from the stable region of the salt hydrate determined by the dissolution equilibrium between the salt hydrate and water, but in many cases, about 1/10 to 1/3 of the number of moles of hydrate of the salt hydrate. It is. As the solid-liquid separation inhibitor, a water-soluble polymer, a water-swellable polymer, a highly water-absorbent resin, a silica thickener, and the like are used. In addition to these salt hydrates, a melting point adjusting agent, a dispersant, an antifoaming agent, a corrosion inhibitor, a coloring agent, and the like can be added.
[0010]
The heat storage device of the present invention is a heat storage device using such a heat storage material, and the heat storage material is usually filled in one container, and is classified into three adjacent portions having different functions.
These three parts express different functions depending on operations such as heating and cooling. The apparatus for heating and cooling may be installed outside or inside the container filled with the heat storage material. When a heating or cooling device is installed inside the container, it is preferable that the device does not cause a chemical reaction with the heat storage material. The heating and cooling device is preferably installed outside the container because it is easy to manufacture.
[0011]
(A) The seed crystal part contains salt hydrate crystals and is always kept below the melting point. In order to maintain the temperature below the melting point, a method such as forced cooling, cooling or heat insulation may be employed according to the melting point . The size of the portion of this is adjacent to the operation such as heating and cooling (B) may be any size necessary to keep the melting point or less under the influence of inflow of heat from the switching part, for example thick In the case of a flat container having a length of about 10 mm, a width of 300 mm, and a length of about 600 mm, the length of the (A) seed crystal part is preferably 20 mm or more, more preferably 50 mm or more.
[0012]
(B) Does the switch part have a structure that can be heated or heated and cooled by an external operation, and can the crystal propagation from the (A) seed crystal part to the (C) main body part? , Has a function of a switch of disabling. Electric heating or hot water is usually used for heating, and electronic cooling, water cooling, air cooling or the like is usually used for cooling. (B) The switch portion preferably has these heating devices or has a heating and cooling device. The shape of this part may be the same as or different from the seed crystal part (A). The size of this part is sufficient if at least a part can be completely melted during heating. For example, in the case of the flat plate-like container, the length of this part is preferably 10 mm or more, more preferably It is 20 mm or more.
[0013]
(C) The main body part is a main part of heat storage and heat dissipation capable of storing and releasing heat, and usually has a heating device for heat storage, for example, facilities such as electric heat or hot water. (C) After the main body portion is stored, when the heating is stopped, it is cooled and becomes a supercooled state. In the case where it is cooled to a considerably low temperature and, as a result, there is a possibility that the supercooling may be broken, it is preferable to perform appropriate heat insulation in order to maintain the supercooling.
[0014]
The heat storage material composed of these three parts (A) to (C) is not separated by an air layer, a heat insulating material, or the like, and is naturally continuous. The container filled with the heat storage material must have a shape capable of crystal propagation from the (A) seed crystal part to the (C) main body part through the (B) switch part. The cross-sectional shape may be either a circle or a distance, and is not particularly specified. The cross-sectional area should just have the width required for crystal propagation.
[0015]
Next, details of an example of the heat dissipation control method will be described. When storing heat, (C) the main body part and (B) switch part are heated to the melting point or higher. After both portions are sufficiently melted, (C) heating of the main body portion is stopped and (B) heating of the switch portion is continued. Thus, (C) the main body part is allowed to cool to below the melting point. In this case, the main body portion (C) is supercooled. Next, when it is desired to dissipate heat, (B) the heating of the switch portion is stopped or cooled. As a result, when the (B) switch portion is cooled to below the melting point, the crystal propagates from the (A) seed crystal portion, and the crystallization proceeds to the (C) main body portion via the (B) switch portion. Thus, heat of crystallization is dissipated as crystallization progresses. In applications where (C) the difference in heat radiation time between one end and the other end of the main body portion is a problem, a method such as (C) shortening the length of the main body portion or dividing it into small sections is preferable. Conversely, when it is desired to positively use the difference in heat dissipation time, (C) a method of increasing the length of the main body is preferable.
[0016]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
[0017]
Example 1
(Example of heat dissipation control by switch operation in part (B))
An aqueous solution of sodium acrylate 20 wt% obtained by neutralizing acrylic acid with sodium hydroxide to pH 7.0, 7.50 g, water 24.00 g, and disodium hydrogen phosphate anhydrous 15.84 g were collected at 50 ° C. In a water bath to obtain a clear solution. After dissolving 0.025 g of N, N′-methylenebisacrylamide and 0.03 g of potassium peroxodisulfate, 0.03 g of sodium sulfite dissolved in 2.01 g of water was added to the above solution and immediately 25 mm wide. When one end of 300 mm in length was poured into a polyethylene bag sealed, a hydrous gel (length 245 mm, thickness 10 mm) having no fluidity was obtained after 2 minutes. This was kept at 40 ° C. overnight and then cooled to 15 ° C. to solidify the whole. The number of moles of water relative to 1 mole of disodium hydrogen phosphate in this composition was 16 moles.
A portion having a length of (A) 95 mm, (B) 50 mm, and (C) 100 mm in order from one end of the solidified composition was marked and divided into three portions, and a thermocouple was attached to each central portion. . A planar heating element was installed under each of the parts (B) and (C), and the top and bottom of (B) and (C) were wrapped with a 20 mm thick heat insulating material. After (B) and (C) were heated to 45 ° C. for 4 hours and sufficiently melted, the planar heating element of (C) was turned off, and the temperature of the central part of (C) was 1 hour later. Although it dropped to room temperature (21 ° C.), the central part of (B) was maintained at 45 ° C.
Next, when the power source of the planar heating element (B) was turned off after 2 hours, the temperature in the central part of (B) rose again to 30 ° C immediately after reaching 30 ° C, and kept at the temperature for 90 minutes. After that, it gradually decreased to room temperature. (C) The temperature of the central portion rose rapidly after 2 minutes from the re-rise of (B) and reached 29 ° C.
[0018]
Comparative Example 1
(Example in which heat dissipation is not controlled because there is no switch part)
About the same composition as Example 1, after heating (B) and (C) to 45 degreeC for 4 hours and making it fully fuse | melt, the power supply of the planar heating element of (B) and (C) is turned off simultaneously. As a result, (B) the temperature of the central portion rose again immediately after dropping to 31 ° C. and reached 32 ° C. (C) the temperature of the central portion suddenly rose after 2 minutes from the re-raising of (B) the central portion ( 30 ° C to 31 ° C).
[0019]
Example 2
(Example of heat dissipation control by switch operation in part (B))
27.51 g of anhydrous sodium acetate and 22.51 g of water were collected and heated in a water bath at 60 ° C. to obtain a transparent solution. To this, 1.50 g of “Sumifloc FN-15H” (Sumitomo Chemical Co., Ltd.) which is a polyacrylamide partial hydrolyzate was added and stirred for 5 minutes, and then sealed in a polyethylene bag with one end of 25 mm width and 270 mm length. Poured and sealed. This was immersed in a 60 ° C. water bath for 2 hours, allowed to cool to room temperature, opened, and several seed crystals were added to crystallize the whole, which was then sealed again. The number of moles of water relative to 1 mole of anhydrous sodium acetate in this composition was 3.7 moles.
The solidified composition was divided into three parts in the same manner as in Example 1, and a planar heating element and a heat insulating material were arranged. (B) and (C) were heated to 65 ° C. for 4 hours and sufficiently melted, and then the sheet heating element (C) was turned off. The temperature in the center part of (C) was 6 hours later. Although lowered to 19 ° C, the central part of (B) was maintained at 65 ° C.
Next, when the planar heating element (B) was turned off after 6 hours, the temperature in the central part (B) rose again to 46 ° C. and immediately reached 48 ° C. (C) The temperature of the central part rose rapidly after 11 minutes from the rise of (B) and reached 44 ° C.
[0020]
【The invention's effect】
According to the present invention, it is possible to control the heat release of a heat storage material mainly composed of salt hydrate, and heat can be taken out when it is required for heating a building, so that more economical operation is possible.

Claims (2)

A heat storage device formed by filling a container with a heat storage material containing a salt hydrate, (A) a seed crystal part having a cooling or cooling device, (B) a heating device or a heating and cooling device A switch part capable of heating operation or heating and cooling operation, (C) a main body part capable of storing and dissipating heat having a heating device , and three adjacent parts , and the shape of the one container is cylindrical, coiled Or a heat storage device capable of controlling heat dissipation. A heat storage device in which a single container is filled with a heat storage material containing a salt hydrate, and (A) a seed crystal part in which a seed crystal having a cooling or cooling device is held, (B) a heating device or A switch portion having a heating and cooling device and capable of heating operation or heating and cooling operation; (C) a main body portion having a heating device and capable of storing and releasing heat; and three adjacent portions , and For a heat storage device having a cylindrical shape, a coil shape, or a flat plate shape , (A) crystal propagation from the seed crystal portion to (C) the main body portion is performed (B) heating and heating stop operation or heating and A heat dissipation control method for a heat storage device using a heat storage material containing a salt hydrate, which is controlled by a cooling operation.