JPS61185583A - Heat storage material composition - Google Patents

Abstract

PURPOSE:A heat storage material composition showing improved preventing effect on supercooling, obtained by blending a main component consisting of calcium 6 hydrate with a specific amount of barium sulfide and a specific amount of barium chloride dihydrate as nucleating agents for supercooling prevention. CONSTITUTION:A main component consisting of calcium chloride 6 hydrate is blended with (A) 0.001-5wt% barium sulfide and (B) 0.05-5wt% barium chloride dihydrate as nucleating agents for supercooling prevention, to give the aimed heat storage material composition. EFFECT:Supercooling temperature can be suppressed to <=2.0 deg.C, and latent heat use temperature can be more accurately controlled.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a heat storage material composition containing calcium chloride hexahydrate as a main component, in which appropriate amounts of barium sulfide and barium chloride dihydrate are used as a core for preventing supercooling. The present invention relates to a technique in which the additive is added as an agent, thereby substantially avoiding supercooling.

[Prior Art] Calcium chloride hexahydrate has a large latent heat of solidification and fusion unique to hydrates, and has a freezing point of about 30°C, which is around room temperature, so it is used in greenhouses for greenhouse horticulture and cultivation, It is beginning to be widely put into practical use for home heating, chemical heat pumps, etc. However, this compound has a major problem in that it causes a significant supercooling phenomenon, which is an obstacle to its practical application. In other words, the supercooling phenomenon is a phenomenon in which a liquid phase substance does not change from a liquid phase to a solid phase even after passing the freezing point in the process of being cooled, and solidification begins only after the substance has cooled considerably below the freezing point. The temperature at which the latent heat of solidification should be generated, that is, the freezing point, becomes unspecified, which is a fatal flaw for a latent heat material intended to maintain a specific temperature range. In order to solve these problems, a technique has been proposed to prevent supercooling by adding a nucleating agent to the calcium chloride 6 water to promote its crystallization (for example, Japanese Patent Publications No. 55-32749 and No. 56-59).
No. 959, etc.), and their practical application is progressing rapidly. Many substances are known as such nucleating agents, such as strontium chloride hexahydrate, strontium hydroxide octahydrate, strontium oxide, barium hydroxide octahydrate, pallium carbonate, and barium nitrate. 0.1 in the heat storage material composition
By containing about 20% by weight, the supercooling phenomenon of calcium chloride hexahydrate can be significantly suppressed.

[Problem that the invention seeks to solve]

However, according to the inventors' reexamination of the effectiveness of various nucleating agents, supercooling of approximately 3 to 4 degrees Celsius cannot be avoided no matter which nucleating agent is used. It has been confirmed that no further effect can be expected even if the nucleating agent is contained in an amount of 20% or more.Under these circumstances, the present invention exhibits a supercooling prevention effect superior to that of conventional nucleating agents. The aim is to further improve the properties of heat storage materials by searching for nucleating agents.

[Means for solving the problems] The composition of the heat storage material composition according to the present invention includes calcium chloride 6
Barium sulfide: o,oot~5% (wt% in the total heat storage material composition: the same hereinafter) and barium chloride 2 as a nucleating agent for supercooling prevention 1F in a heat storage material composition mainly composed of aqueous salt.
Water salt: The gist is that it contains 0.05 to 5%.

[Function] When a heat storage material composition consisting essentially of calcium chloride hexahydrate is lowered in temperature from a molten state, it does not solidify even after passing its freezing point of about 29.5°C, and as shown in FIG. As shown by the solid line, solidification begins rapidly when the temperature reaches about 20°C, for example. However, since the degree of supercooling changes significantly depending on the rate of cooling and disturbance of the melt, it is not possible to specify the temperature at which latent heat is generated, and temperature control according to the usage temperature must be inaccurate. On the other hand, when about 5% by weight of strontium chloride hexahydrate, for example, is contained as a nucleating agent for preventing supercooling, the supercooling phenomenon is significantly alleviated and suppressed to about 3 to 4 DEG C., as shown by the broken line in FIG. The effect of suppressing supercooling by known nucleating agents is not perfect, although the optimum content varies slightly depending on the type of nucleating agent, and this does not mean that supercooling can be suppressed to a substantially permissible range. do not have.

However, as the present inventors conducted experiments with various compounds, it was confirmed that the supercooling phenomenon could be extremely effectively suppressed by using a certain amount of barium sulfide and barium chloride dihydrate together. As will be clarified in the examples below, a heat storage material composition containing calcium chloride hexahydrate as a main component contains o,oot~5% of barium sulfide and 0.05~5% of barium sulfide.
It has become clear that supercooling can be suppressed to 2° C. or less by coexisting barium chloride dihydrate at a temperature of 1.5%. Here, if the amount of barium sulfide or barium chloride 2 wood salt is less than the lower limit, a synergistic supercooling suppressing effect cannot be expected by using both together, and insufficient supercooling suppressing effect by using the cloth alone (
On the other hand, if the content of both of the above components exceeds the upper limit, solidification may not occur or the amount of solidified WJ8 may be significantly reduced, resulting in a heat storage material. As a result, the performance and stability become poor. More preferable contents of barium sulfide and barium chloride dihydrate are in the range of 0.1 to 3% for rin and 0.1 to 3% for the latter.

As described above, the present invention is characterized in that the two types of nucleating agent components mentioned above are contained in fixed amounts in the heat storage material composition containing calcium chloride hexahydrate as the main component. If necessary, thickeners, freezing point regulators, etc. can be added in appropriate amounts. In other words, thickeners have the function of imparting appropriate viscosity to the molten liquid in use, and in particular preventing the settling of nucleating agents to stably exert the supercooling suppressing effect. Methyl cellulose etc. are used. Freezing point regulators are compounds added to adjust the freezing point of the heat storage material composition to control the temperature at which the latent heat of solidification and melting occurs.For example, iron chloride hexahydrate, copper chloride dihydrate, magnesium chloride hexahydrate, etc. water salt,
Any known freezing point regulator such as cobalt chloride hexahydrate, or calcium nitrate 4 discovered by the wood inventors.
Water salt, zinc chloride, etc. can all be used.

[Example] First, the supercooling suppressing effect when barium sulfide and barium chloride are contained alone as nucleating agents is shown in Section 1.2.
As shown in the figure. In addition, for the experiment, calcium chloride 6 water
1 contains 0.001 to 10% of sulfide/<lium or barium chloride 2 and is melted using each heat storage material composition.
After repeated solidification, the degree of supercooling of S (see Figure 8) was investigated.

Table 1 Example of formulation using BaS as a nucleating agent Table 2 Example of formulation using BaCl2.2H20 as a nucleating agent 1st
．． As is clear from Figure 2, BaS or BaG1?・2H2
If 0 is used alone as a nucleating agent, a satisfactory supercooling prevention effect cannot be obtained. In the above experimental examples, samples Nos. 6 and 11 contained too much nucleating agent, so they did not solidify at all at the original solidification temperature and could not be used as heat storage materials.

Next, we investigated the supercooling suppressing effect when appropriate amounts of barium sulfide and barium chloride dihydrate were used together as nucleating agents. That is, as shown in Table 3, heat storage material compositions of barium sulfide and barium chloride dihydrate were prepared in various amounts and melting and solidification were repeated.
- The results of the combined use of 2H20 are shown in Figures 3 to 7. Note that the symbols in the figure correspond to the experiment numbers in Table 3.

The results of these experiments can be thought of as methods.

(1) When the barium sulfide content is less than 0.001%, sufficient supercooling suppression effect cannot be obtained even if the barium chloride dihydrate content is within the appropriate range; %, it may not solidify (Experiment No. 21.26, 31°36), and even if it solidifies, the amount of latent heat of solidification decreases, and its performance as a heat storage material is significantly reduced.

(2) 11! Barium dihydrate content is 0.05%
Even if the temperature is below 2 to 3°C, the synergistic supercooling suppressing effect with barium sulfide is not exhibited, and in any case, the temperature is 2 to 3°C.
The degree of supercooling exceeds . It was also confirmed that when the amount of barium chloride dihydrate exceeds 5%, the solidification may not occur as in the case where there is too much barium chloride sulfide.1 Furthermore, even when solidification occurs, it has been confirmed that the amount of latent heat of solidification is significantly reduced.

(3) On the other hand, when sulfide/<lium and barium chloride dihydrate are both included in appropriate amounts, the supercooling suppressing effects of both are synergistically exhibited, and in both cases, the degree of supercooling can be suppressed to 2°C or less. I can do it.

The synergistic supercooling suppressing effect of barium sulfide and barium chloride dihydrate on a heat storage material composition containing calcium chloride hexahydrate as a main component is as described above. Since it is customary to use thickeners and freezing point regulators in combination, we will exemplify some typical heat storage material compositions containing these subcomponents, and also explain the freezing point and degree of supercooling (10 The average value obtained when repeated 2 times) is also listed.

(A) Main component (CaC1?・6H20): Residual freezing point regulator (ZnCl2) + l 0% nucleating agent (
BaS): 0.1% (BaC12・6HzO):
0.8% thickener (glycerin) = 3% Freezing point: 20°C, degree of supercooling = 1.2°C (B) FJ&min (CaG12-8H20): Balance freezing point regulator (NaBr): 10% nucleating agent
(Has): 0°01% (C: aC12・6H2
0): 1% thickener (fine powder silica: 5i02):
3% freezing point = 24℃, degree of supercooling: 0.7℃ (C) iE component (CaCI2, 6thO): Residual freezing point regulator (NHJr): l 0% nucleating agent
(BaS): 0.001% (BaS 12/2H2
0): 0.8% thickener (CMC): 3
% Freezing point = 18℃, degree of supercooling: 1.1℃ (D) Seven components (CaCI2・8H20): Residual freezing point regulator (KBr): 20% nucleating agent (B
aS): 0.01% (BaC12・2H20)
+ 0.5% thickener (fine powder silica): 2.5% Freezing point: 15°C, degree of supercooling 20.6°C (E) Main component (CaCI2・[1H20): Residual freezing point regulator (CaBr2・6H20): 14% nucleating agent
(BaS): 0.001% (BaC12
・2H20): 2% thickener (glycerin):
3% Freezing point: 19°C, degree of supercooling: 1.5°C [Effects of the invention] The present invention is constructed as described above, but the key point is to use an appropriate amount of barium sulfide and chloride/helium dihydrate together as a nucleating agent. By doing so, the degree of supercooling of the heat storage material composition containing calcium chloride hexahydrate as a main component can be suppressed to 2.0'C or less, and the latent heat utilization temperature can be controlled more accurately.

[Brief explanation of drawings]

1 to 7 are graphs showing the degree of supercooling of the heat storage material compositions obtained in Examples, and FIG. 8 is a graph illustrating the supercooling curve of the heat storage material M1 composition. + of ψ? To n - 擢 (Koroken (Q) I4) lj'l Ma n to -uta (Koroya (p) (-Co ■ 0, -1 + S +N 1 I Ma - to - Shizuku (
! Go (,Q)

Claims (1)

[Claims] In a heat storage material composition containing calcium chloride hexahydrate as a main component, barium sulfide is used as a nucleating agent to prevent supercooling: 0.001 to 5% by weight (content in the total heat storage material composition) A heat storage material composition characterized by containing 0.05 to 5% by weight of barium chloride dihydrate.