JPS62132532A - Method for granulating latent heat type heat storage material - Google Patents

Abstract

PURPOSE:To form a uniform granular body and to remarkably shorten a granulating process of a latent heat type storage material by cooling and solidifying a metal liquid of the latent heat type heat storage material while stirring it. CONSTITUTION:Stirring of a degree overcoming at least crystal growth velocity and flocculation velocity of a melted liquid of a latent heat type heat storage material (e.g. inorganic hydrate such as CaCl2.6H2O) is performed for the melted liquid of the latent heat type heat storage material. A granular material having about 0.1-5mm grain size is obtained by cooling and solidifying the melted liquid preferably in about 0.5-5 deg.C/min velocity while stirring it. Still further stirring may be performed by rotation and/or vibration from the inside and/or outside of a vessel incorporated with the melted liquid of the latent heat type heat storage material. Also the melted liquid may be added with a nucleating agent and/or a thickening agent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for easily obtaining granular heat storage material with relatively uniform particle size that is easy to handle.

(Prior Art) In order to improve the transportability and handling workability of latent heat type heat storage materials that absorb and release latent heat through melting and solidification, they are granulated.

In addition, in heat storage material capsules manufactured by applying surface coating to granular materials, in order to prevent stress concentration from occurring in the capsules during volume changes such as melting and solidification, the latent heat type heat storage material is granulated in advance. It is an important thing to let them do so.

By the way, when preparing latent heat type heat storage materials, in order to uniformly mix the heat storage material raw materials and additives such as supercooling prevention materials, a method is adopted in which they are heated and melted once. After such heating and melting, the latent heat type heat storage material obtained by cooling becomes a lump at room temperature.

Therefore, in order to handle the obtained latent heat type heat storage material, such as storing it in separate containers, it has been necessary to heat and melt it again, or to crush the lumps.

(Problems to be Solved by the Invention) However, in the method of heating and melting, the container must be kept at a high temperature in order to prevent the melt from cooling and solidifying during dispensing. Workability was poor because there was a risk of getting burnt if the water was removed as is.

On the other hand, latent heat type heat storage materials, especially inorganic hydrates, have an inorganic component and a crystal water component combined in a certain ratio, and the crystal water content is strongly influenced by the humidity of the outside air. The latent heat type heat storage material easily deteriorates in quality. Therefore, when a lump is pulverized into granules, it must be ground in a sealed state, which also has poor workability.

(Means for Solving the Problems) The inventor of the present invention conducted research in view of the above problems and found that, as described above, when the heat storage material melt is cooled and solidified in a stationary state after melting, it becomes a solid lump. I'll put it away.

It was accidentally discovered that by cooling and solidifying it while stirring, it becomes a large number of almost uniform granules.

- The reason for this is not clear, but the reason for this is that normally, the crystal nuclei generated when the heat storage material solidifies, grow as they are, and aggregate together to form a single lump, but by artificial stirring, When the melt is in strong relative motion with respect to each other, the generated crystal nuclei cannot grow as they are, and the nuclei are crushed by collisions between the nuclei and the walls of the container.
This is thought to be because secondary nucleation occurs and the grown microcrystalline grains also undergo intense relative motion, making it impossible for them to aggregate with each other, resulting in them remaining as crystalline grains of uniform size.

Therefore, imparting intense relative motion to the melt (which can be achieved by rotational stirring or shaking stirring) is very effective in granulating the heat storage material.

In the present invention, the application of intense relative motion to the melt can be performed by stirring the melt contained in the container by rotation and/or shaking from inside and/or from the outside.

As the latent heat type heat storage material, inorganic hydrates such as those exemplified below are generally used.

11 Water ■] - JL Stand - 1 JJ [CaCl2・6t+20 29℃ 1
．． 5ONa2CO: + + 10H2032℃
135Na2S0. □ 1011+0
1.3ONaiPO1・12H2036℃
1.42Zn (No, >2 ・61120
1.80Ca(N(ls)i・
4H2045℃ 1.72Na2
S20z ・51120 48℃ 1.
65C)+3COONll ・3H-058℃
1,32 Note that a nucleating agent to prevent supercooling and/or a thickening agent to prevent phase separation are usually added to these inorganic hydrates.

The stirring force in the method of the present invention needs to be at least strong enough to overcome the crystal growth rate and aggregation rate of the latent heat storage material melt, and the cooling rate is usually 05 to 5°C/m
The particle size of the resulting granules is preferably about 0.1 to 5 mol.m.

(Implementation PA) Sodium acetate trihydrate (NaCHyCOo・3H
20) Supercooling prevention material (nucleating material) (melting temperature 58°C)
as trisodium phosphate dodecahydrate (Na=PO1
- 3% by weight of 12H20> was added, and 60g of this was stored in a polyethylene container of 100 pieces, and then heated to 80°C to completely melt it.

Next, the heat storage material was cooled to room temperature while being shaken twice per second to solidify the heat storage material.The solidified heat storage material became uniform crystal grains with a particle size of 1/1 m, making it easy to store and handle. It has become very easy to divide the product into separate containers.

<Effects of the Invention> According to the present invention, it is possible to obtain a large number of uniform crystal grains simply by applying mechanical stirring when cooling and solidifying the prepared heat storage material melt, and as a result, the granulation of the melt is reduced. The process can be made significantly more flexible. The obtained latent heat type heat storage material can be easily taken out, and its transportability, workability and safety when storing it in other containers (in other containers) are improved.

Claims (5)

[Claims] (1) A method for granulating a latent heat type heat storage material, which comprises cooling and solidifying a melt of the latent heat type heat storage material while stirring. (2) The method for granulating a latent heat type heat storage material according to claim 1, wherein the latent heat type heat storage material is an inorganic hydrate. (3) The method for granulating a latent heat type heat storage material according to claim 1 or 2, wherein the melt of the latent heat type heat storage material is contained in a container. (4) According to any one of claims 1 to 3, wherein stirring is performed by rotation and/or shaking from inside and/or outside of the container containing the melt of the latent heat storage material. A method for granulating the latent heat type heat storage material described above. (5) The latent heat type heat storage material according to any one of claims 1 to 4, wherein the melt of the latent heat type heat storage material has a nucleating agent and/or a thickener added thereto. Granulation method.