JPS6236486A - Heat storing material - Google Patents

Abstract

PURPOSE:To obtain at low cost a heat storing material capable of stably exhibiting a supercooling preventing effect for a long period of time, by incorporating a double salt of calcium chloride with calcium oxide as a nucleating agent in a heat storing material comprised mainly of calcium chloride hexahydrate. CONSTITUTION:A heat storing material comprised mainly of calcium hexahydrate is blended with 1-20pts.wt., based on 100pts.wt. calcium chloride hexahydrate, double salt of calcium chloride with calcium oxide as a nucleating agent to obtain an intended heat storing material. The double salt of calcium chloride with calcium oxide is represented by the formula CaCl2.CaO.2H2O. The double salt can be easily incorporated in calcium chloride hexahydrate, e.g., by adding calcium hydroxide and (or) calcium oxide to calcium chloride hexanydrate in a molten state and cooling the mixture at about 10 deg.C or below, thereby precipitating the double salt of calcium chloride with calcium oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel heat storage material containing calcium chloride hexahydrate as a main component.

[Prior art and problems] Calcium chloride hexahydrate is attracting attention as a heat storage material because it has a large heat storage density (heat of fusion) and is inexpensive, but it exhibits a significant supercooling phenomenon. However, it is difficult to repeatedly store and release heat in a stable manner, which poses problems in practical application. For this reason, a method has been proposed in which a nucleating agent such as an oxide such as strontium or barium, a hydroxide, or a chloride is added to calcium chloride/hexahydrate to prevent the supercooling phenomenon. However, these nucleating agents have problems because they are insufficiently reliable for practical use and are very expensive compared to calcium chloride/hexahydrate. Development of salt is desired.

Therefore, in the heat storage material of the present invention, calcium chloride and calcium oxide may be present in the above double salt form in the calcium chloride/hexahydrate salt as the main component.

[Means for solving the problem] As a result of many years of research into the nucleating agent of calcium chloride/hexahydrate, the present invention has found that the double salt of calcium salt and calcium oxide is equivalent to the conventional nucleating agent. The present invention was completed by discovering that it has a supercooling prevention effect that is even more effective than that. That is, the present invention is a heat storage material containing calcium chloride/hexahydrate as a main component, and is characterized by containing a double salt of calcium chloride and calcium oxide.

According to the present invention, the double salt of calcium chloride and calcium oxide is represented by the general formula CaCQ2.Ca0.2H20. In this way, the content of the double salt of calcium chloride and calcium oxide present in the salt of calcium chloride 67 is:
Generally, 1 to 20 parts by weight, preferably 5 to 10 parts by weight, is suitable for 100 parts by weight of the calcium chloride hexahydrate salt. In other words, if the content of double salt is less than the above range, the effect of preventing the supercooling phenomenon of calcium chloride/hexahydrate will not be sufficiently exhibited, and if it is more than the above range, the content per unit weight of heat storage material will be insufficient. The amount of heat stored tends to decrease.

There are no particular restrictions on the method of incorporating a double salt of calcium chloride and calcium oxide into the calcium chloride hexahydrate salt. To illustrate the most suitable method, calcium chloride and calcium oxide are combined by adding calcilla hydroxide 11 and/or calcium oxide to molten calcium chloride hexahydrate and cooling it to 10°C or less. A simple method for precipitating double salts is mentioned. In this case, water necessary for crystallization water of the above-mentioned double salt may be replenished into the system as necessary. According to the above method, fine double salts can be uniformly dispersed in calcium chloride/hexahydrate salt, so that the supercooling prevention effect can be further enhanced. Of course, a double salt of calcium chloride and calcium oxide is generated in advance,
It is also possible to add the double salt directly to the calcium chloride hexahydrate salt.

In the heat storage material of the present invention, other components may be added as appropriate within the range where calcium chloride hexahydrate is the main component. Such additive components include, for example, magnesium chloride, urea,
Examples include known nucleating agents. In particular, magnesium chloride and urea are suitably used to lower the heat storage temperature by lowering the melting point of calcium chloride/hexahydrate, and are effective in applications where heat storage agents are used in relatively low temperature ranges, such as for example in greenhouse horticulture. . In this case, the amount of magnesium chloride added is 1 part by weight per 100 parts by weight of calcium chloride hexahydrate.
The amount of urea added is preferably 1 to 5 parts by weight per 100 parts by weight of calcium chloride hexahydrate.

[Effects] Since the heat storage material of the present invention uses a double salt of calcium chloride and calcium oxide as a nucleating agent, it is extremely economical compared to a heat storage material using a conventional nucleating agent.
Demonstrates excellent supercooling prevention effect. In addition, since the nucleating agent used in the heat storage material of the present invention is a double salt containing calcium chloride as one component, it is stable in calcium chloride/hexahydrate, and is effective in preventing supercooling even after repeated use over a long period of time. It is characterized by almost no loss.

[Examples] Examples are shown below to explain the present invention in more detail, but the present invention is not limited to these Examples.

Example 1 Calcium hydroxide was added at a ratio of 3% by weight to calcium chloride hexahydrate in a molten state (30°C), and then cooled to 5°C to solidify. X-ray diffraction analysis of the same vehicle confirmed that a double salt of calcium chloride and calcium oxide was present in this coagulated material.

After melting the obtained heat storage material at 30°C in a test tube,
The test tube was placed in a constant temperature bath at ℃, and the temperature change in the test tube was measured over time. Table 1 shows the temperature measured every 10 minutes and the supercooling temperature. The supercooling temperature was expressed as the difference between the lowest temperature until the melt was assimilated and the highest temperature thereafter.

Example 2 Calcium chloride hexahydrate 80 in molten state (30°C)
After adding 3.5 parts by weight of urea and 3 parts by weight of calcium hydroxide to 100 parts by weight of a mixed solution of 20 mol% of magnesium chloride, the mixture was cooled to 5° C. and solidified.

X-ray diffraction analysis of the same vehicle confirmed that a double salt of calcium chloride and calcium oxide was present in this coagulated material.

The obtained heat storage material was subjected to the same test as in Example 1. The binding is also shown in Table 1.

Moreover, the performance of the heat storage materials of Examples 1 and 2 did not deteriorate at all even when the above experiment was repeated many times.

Claims (1)

[Scope of Claims] 1. A heat storage material containing calcium chloride/hexahydrate as a main component, which is characterized by containing a double salt of calcium chloride and calcium oxide. 2. The heat storage material according to claim 1, wherein the double salt of calcium chloride and calcium oxide is present in an amount of 1 to 20 parts by weight based on 100 parts by weight of calcium chloride hexahydrate.