JPS58136683A - Thermal energy storage material - Google Patents

Abstract

PURPOSE:A thermal energy storage material undergoing suppressed supercooling which is prepd. by adding a specified nucleator to CaCl2.6H2O. CONSTITUTION:0.1-10wt% at least one nucleator selected from BaHPO4, BaCrO4 and BaAl2O4 is added to 100wt% CaCl2.6H2O.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat storage material mainly composed of calcium chloride hexahydrate.

Calcium chloride hexahydrate (CaC4.6H, 0, melting point 28
C) 1! Since it is inexpensive and has a large amount of latent heat, it is a promising substance as a latent heat storage material for air conditioning. However, during heat dissipation, supercooling *'
occurs significantly, and does not release latent heat even if the temperature drops by 20C or more below the freezing point. Therefore, it cannot be used as a heat storage material unless this undesirable supercooling phenomenon is solved.

The object of the present invention is to suppress the supercooling phenomenon of calcium chloride hexahydrate described above and to reform it into a material that can be easily used as a heat storage material.

For this reason, we conducted a trial-and-error search for a nucleating agent that facilitates nucleation of calcium chloride hexahydrate. As a result, barium phosphate (B a HP 04 ), barium chromate (
EiaCrO,)'*Aluminum oxide barium (Ba
A4. O,) was found to be extremely effective as a nucleating agent.

Examples of the present invention will be described below.

[Example 1] 3 g of barium phosphate to 100 g of calcium chloride hexahydrate
't' added to the mixture was placed in a polyethylene container, and this container was placed in a hot water tank and heated to about 5 Or.
After that, this is 10t? Place the sample in a cold water bath to allow it to cool, and record the temperature of the sample.

After supercooling the freezing point of 28C to 3, the supercooling recovered to 25C, and then the sample temperature reached H28tl' and began to release latent heat of solidification. When the same operation was repeated 10 times on the same sample, the degree of supercooling was kept to about 3C all 10 times. The latent heat of this heat storage material was measured with a differential calorimeter and was found to be 43 kcal/Kg.

[Example 2] Add 0 barium chromate to 100 g of calcium chloride hexahydrate.
．． The mixture to which 1 gTh was added was placed in a polyethylene container, and the container was placed in a hot water bath and heated to approximately 50C.Then, the mixture was placed in an 'el OC cold water bath and left to cool. Temperature was recorded. Freezing point 28Ct-4t
After 1' supercooling, supercooling was recovered at 24C, and then the temperature of the sample reached 28C and began to release latent heat of solidification. When the same operation was repeated 10 times on the same sample, the degree of supercooling could be suppressed to about 4C all 10 times. The latent heat of this heat storage material sample was measured with a differential calorimeter.% 43kc
It was al/q.

[Example 3] A mixture of 100 g of calcium chloride hexahydrate and 10 g'i of barium aluminum oxide was placed in a polyethylene container, and the container was placed in a hot water tank to produce approximately 50 tons of water.
The sample was heated to 1' and then placed in a cold water bath of 11 OC to allow it to cool, and all temperatures of the sample were recorded. Freezing point 28t
After supercooling r by 3C, supercooling recovered at 25C, and then the temperature of the sample reached 28C and began to release latent heat of solidification. When the same operation was repeated 10 times for the same sample, 1
The degree of supercooling could be suppressed to about H3tr for both times.

As a result of measuring the total latent heat of this heat storage material sample with a differential calorimeter, 43
k c a 1. /Kg Te1> Tsuft.

The amount of nucleating agent added may be extremely small, and Example 2
As shown in the figure, even 0.1 weight percent is sufficiently effective. There is no particular upper limit to the amount of nucleating agent added, but if too much is added, the heat storage capacity will decrease, so it is preferably 10% by weight or less.

The figure shows the solidification characteristics of the heat storage material, and the horizontal axis is time t (
h r ), the vertical S is the temperature T (l). In the figure, the curve e is barium phosphate macer fc is when barium aluminum oxide is added, and the curve @ is black As explained above,
According to the present invention, the supercooling phenomenon of the heat storage material is significantly alleviated,
It has come to be put into practical use.

[Brief explanation of the drawing]

The figure is a diagram showing the solidification characteristics of an example of the heat storage material of the present invention. Agent Patent Attorney Toshiyuki Usuda ε (hr)

Claims (1)

[Claims] 1. Calcium chloride hexahydrate with phosphoric acid as a nucleating agent)
) A heat storage material made by adding one or more substances from the group consisting of barium chromate and barium aluminum oxide. 2. Nucleating agent is added from 0.1% by weight to 100% by weight of calcium chloride hexahydrate.