JPS5840379A - Heat storing composition - Google Patents

Abstract

PURPOSE:To provide a heat storing compsn. which is free from supercooling phenomenon, utilizes latent heat of fusion more effectively at the same cost as in the case of single use of CaCl2.6H2O and stands repeated use, prepared by adding a small amount of Na3PO4.12H2O to CaCl2.6H2O. CONSTITUTION:The heat storing compsn. is prepared by adding 0.005-5pts.wt. Na3PO4 12H2O (B) to 100pts.wt. CaCl2.6H2O (A). The addition of B has advantages in that the latent heat of fusion of component (A) is maintained and utilized more effectively without causing phase separation and a comsistent supercooling preventive effect is obtained in the repeated freeze/thaw cycle. Moreover, the heat storing compsn. costs almost the same as when component (A) is used alone.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a heat storage agent that utilizes latent heat of fusion and thus stores heat.

Traditionally, calcium chloride hexahydrate has a latent heat of fusion of 42 Ka.
Since it has a large O1t/Ky and a melting point of 29°C, it is attracting attention as an extremely suitable heat storage agent for heating systems combined with heat pumps, solar collectors, etc., for example.

4(tl) Lucium hexahydrate has the property of being supercooled to a temperature significantly lower than the melting point when the melt is cooled.Moreover, this supercooling phenomenon is caused by the melting during phase change when heat is released. It has a disadvantage as a heat storage agent because it does not release latent heat and the temperature decreases as an enemy.

It is a well-known fact that as a means to prevent this supercooling phenomenon, supercooling can be prevented by adding seed crystals of the same crystalline solid to the supercooled melt. However, when heated again, the seed crystal melts, making it impractical.

In addition, an additive effective to prevent the supercooling phenomenon of calcium chloride aqueous salt has been proposed in the prior invention, JP-A-53-19183, but when particularly good stability is required, the addition amount Fis parts by weight is proposed. It is necessary to add a large amount of 20 to 20 parts by weight. Moreover, it has the disadvantage that the latent heat of fusion is less than 35 Km/KP.

As mentioned above, there are many problems with measures to prevent the supercooling phenomenon of calcium chloride, and even now, IPK is in the research stage, and it is dangerous to put it into practical use.

The present invention is directed to such blocky Kil! The purpose was to prevent supercooling by adding a small amount of additives to calcium chloride hexahydrate, which could be used more effectively than latent heat melting tubes at the same cost as calcium chloride hexahydrate. An object of the present invention is to provide a heat storage agent that can withstand repeated use.

The above object can be easily achieved by using a composition containing trisodium phosphate dodecahydrate in calcium chloride hexahydrate as a heat storage agent.

The main part of the present invention is to use trisodium phosphate decahydrate as a supercooling inhibitor for calcium chloride hexahydrate. The selection of this inhibitor has been carefully selected from among countless compounds, and its characteristics are that it has been used as a nucleating agent for calcium chloride hexahydrate, and has traditionally been studied from an evitagital perspective. The effect is different from the case using strontium halide hexahydrate, which is considered to be superior.

That is, the inhibitor of the present invention is added in very small amounts, for example, o, oos,
The prevention effect is exhibited at 1 mm part, and conversely, when the amount added exceeds 5]1 part, there is a peculiar phenomenon in which the existence of the #IF issue itself becomes unclear.

In the heat storage agent composition according to the present invention, trisodium phosphate dodecahydrate is placed in 0.005 parts by weight B to 53, and more effectively, 0.1 parts by weight is selected to be 3 parts by weight. desirable.

The heat storage agent composition of the present invention prepared in this manner not only makes it possible to more effectively maintain and utilize the latent heat of fusion of lucicum chloride hexahydrate, but also makes it possible to prevent repeated melting and solidification. However, the effect of preventing supercooling is still the same, and there is an advantage that phase separation does not occur.

The content will be clarified below through Examples and Comparative Examples.

Examples/Comparative Example-1 Calcium chloride hexahydrate 100] [To the tray, o, oosz parts, and 0.0 parts of trisodium phosphate dodecahydrate were added, respectively. Samples containing 1 part by weight, 3 parts by weight, and 5 parts by weight were prepared, and each sample number was sequentially given as 1 and 2°3.4. For comparison, calcium chloride hexahydrate alone and strontium chloride hexahydrate were added to 100 parts by weight of calcium chloride hexahydrate.
0 and 1 mlltm of aqueous salt, 511 parts each, 1
Prepare samples, each with sample numbers A and B in sequence.

Labeled C and D.

Each of the above samples was placed in a cylindrical plastic container with an inner diameter of 60 mm and a height of 1,700 mm, a thermocouple was inserted, and the container was sealed. Thereafter, these eight containers were placed in a constant temperature water bath at 50° C. to completely melt, and then placed in a constant temperature water bath at 0° C., and the temperature of the sample was recorded without analyzing heat radiation.

The measured values of supercooling temperature and solidification temperature for each sample are shown below.

Table-1 Table-1 shows that the law is clear. That is, in the case of only calcium chloride hexahydrate, the temperature drop due to over-N cooling is about 20°C, whereas the temperature drop of the heat storage agent ffi component by the VC of the present invention is within about 3°C.

Therefore, trisodium phosphate 12 water tit (1L105
It can be seen that containing a heavy noodle portion of A to 5 mm has a good supercooling prevention effect.

In addition, since a heat storage agent using strontium chloride hexahydrate as a core agent has the same supercooling prevention effect as the present invention, it is necessary to add K in an amount exceeding 5 parts by weight, and the additive of the present invention requires adding a small amount. It can be seen that there is an effective supercooling prevention effect.

Example/Comparative Example-2 In Example/Comparative Example-1, each sample number 1, 2°, 3.4. C,
The latent heat of fusion of the heat storage agent composition D was measured using a differential calorimeter (DSC). The results are shown in Cloth-2.

Table 2 According to Table 2VC, the latent heat of fusion of the heat storage agent composition of the present invention is 39 Kmt/9 to 37 Kmt/, and the heat storage agent composition using stroftium chloride as a nucleating agent is 3 s Kmt/. K
It can be seen that this is a heat storage agent composition that can utilize the latent heat of fusion for upward movement.

Example-Comparative Example-3 In Example and Comparative Example-1, the heat storage agent compositions of sample numbers 1, 2°4, C, and D, all of which are considered to have an effective supercooling prevention effect, were repeatedly solidified and melted. The supercooling warm temperature and solidification temperature # were measured and shown in Table 3 below.

As shown in Figure 3, the heat storage agent composition of the present invention can be repeatedly applied to V as in the heat storage agent using strontium chloride hexahydrate as a core agent
C It can be seen that the heat storage agent composition is durable.

The present invention provides a heat storage agent composition having the configuration described above, which can use the latent heat of fusion more effectively at the same cost as calcium chloride, and has excellent reversal stability. provided is achieved.

By using the heat storage agent composition of the present invention, it will contribute to the self-effective utilization of Taiba heat, which will become even more popular in the future.

Patent Ni 1 person Asahi Dow Co., Ltd. 61

Claims (1)

[Claims] 7 parts per 100 parts of Lucicum hexahydrate chloride,
Trisodium phosphate dodecahydrate o, oos heavy 1 to brown 5
Heat storage agent composition containing electric parts