JPS582598A - Heat accumulating material - Google Patents

Abstract

PURPOSE:To prevent supercooling of a heat accumulating material, by adding brium acetate to a heat accumulating material of CaCl2.6H2O as a nucleator for preventing supercooling of the heat accumulating material. CONSTITUTION:Barium acetate is added to CaCl2.6H2O as a nucleator for preventing supercooling. Although the nucleator is added at a rate higher than the solubility of the same, it is practically preferable that the amount of the nucleator to be added to CaCl2.6H2O is less than 10wt% of CaCl.6H2O. A thickening agent can be added further to CaCl2.6H2O for the purpose of improving diffusion of the nucleator. As the thickening agent, a high-molecular substance such as carboxymethylcellulose that is dissolved in a heat accumulating material is used. Resultantly, it is enabled to obtain a heat accumulating material capable of preventing supercooling and having a stable performance, absorbing and releasing heat at a fixed temperature.

Description

[Detailed Description of the Invention] +1) Object of the Invention It is an object of the invention to provide a heat storage material that prevents supercooling.

t2) Conventional Example Heat storage methods can be roughly divided into three types: - heat utilization method, latent heat utilization method, and chemical heat storage method. *Thermal storage uses the sensible heat of water, sand, etc., and is widely used. However, this tabpu is made of wood, which has a small heat storage capacity, and the device is large! Chemical heat storage uses reaction heat and dilution heat, but this type of heat storage involves reactions, making it difficult to control and requiring complicated equipment.

On the other hand, SM & heat storage has a large heat storage capacity @vs.
As a latent heat storage material, it is possible to make the device more compact, and it does not require a multi-layered device.Since the amount of heat storage is very heavy, inorganic hydrates and other materials are preferable. is 1. Rice inorganic hydrates have the problem of supercooling. That is, when cooled, it changes from a molten state to l! fil1. Generally speaking, inorganic hydrates often produce coagulation heat even when cooled.
This is often a #-shaped box, which is a supercooled structure, and if this ``kA phenomenon'' occurs, it will not be able to release much solidification heat, and therefore it will be useless as a heat storage material.

Salt [calcium hexahydrate (CaC1r)] is used as an inorganic heat storage material.
15HsO) is known, but this one also had the above-mentioned drawbacks and was rejected. .

(3) Structure of the Invention The present invention provides a heat storage material made by adding barium acetate as a nucleating agent for preventing supercooling to calcium chloride hexahydrate.

Calcium chloride hexahydrate (Caclm@HsO) has a large melting vessel heat of 75 cal/- at 2*C.

However, Caclm (lHso) is easily supercooled to below oc and cannot be used as a heat storage material in a case of .Therefore, the above-mentioned nucleating agent is added above t and sm degrees. Crystallization of the agent Caclm.6 out0 begins. The crystallization process is divided into a crystal nucleus and generation process in which a solid is precipitated from a liquid, and a crystal growth process which is an integrated process.

The generation of a crystal nucleus is treated statistically as a phenomenon of fluctuation in a non-equilibrium state, but in terms of a model, it is generated from an ovule or a solution, which can be called a fragment of a crystal nucleus composed of a small number of opiates. Otherwise, it can be seen as a through-hole that grows and becomes a crystal nucleus. Here, the crystal nuclei are the constituent particles (molecules,
It is conceivable that the number of atoms (atoms, atoms, etc.) is at least several times as large as the 4 unit lattice, and that the arrangement is correct.The ovule grows when it becomes 11 times larger than the critical crystal. do,
Caclm; 61110 is considered to exhibit accumulated supercooling because the energy gap is large when the ovule reaches a size larger than the critical crystal diameter. The nucleating agent is thought to play a role in reducing this energy gap.

Note that the amount of the nucleating agent to be added may be at least 1 degree of solubility, and there is no upper limit on the amount, but from a practical standpoint, it is preferably 10% by weight or less. The thickening agent may be a polymeric substance such as carboxymethyl cellulose (CMC) that is decomposed into the heat storage material.

(4) Examples Example 1 Barium acetate (Ba (
CHICoo) m) to, 2 weight manka saw t heat storage container 1! Closed. The CO one started coagulating at 24C.

This solidification point remains almost the same even after repeated solidification 110 times! The behavior represented by B in the graph shown as 0 corresponds to this n. Nasi,
In the same glare, C-1 is shown as a comparative example and shows the behavior when there is no nucleating agent. CM is added to the heat storage material composition as a nucleating agent.
C1G, 1 wt.-added tS sealed in a heat container.This material had better dispersion stability of the 411E agent than the heat storage material of Example 1. The heat storage properties were approximately the same as in Example 1 (6'').

(Shima) Effect Since the present invention includes the addition of a lI-nucleating agent, the following effects can be achieved.
4.

H) Overcooling is prevented (- It becomes a stable heat storage material that absorbs and releases heat at a constant temperature.

(c) The flexibility of Caal16111O itself is not affected by the nucleating agent.

[Brief explanation of the drawing]

The figure is a graph of temperature change (1*Way) during cooling of the heat storage material. License applicant. Matsushita Electric Works Co., Ltd. Representative: Toshimaru Takemoto (and 21 other people)

Claims (1)

[Scope of Claims] a) A heat storage material made by adding barium acetate (T) to calcium chloride hexahydrate as a nucleating agent to prevent supercooling. (2) The heat storage material according to claim 1, in which a nucleating agent is added in an amount equal to or more than #1. The heat storage material according to claim 1 or 2 of claim d.