JPH06220436A - Heat storage composition - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a heat storage material composition that reduces the degree of supercooling during solidification, exhibits stable nucleation performance against high temperatures during melting, and solidifies reliably. [Constitution] Sodium acetate trihydrate (CH3COONa
· _3H to 2 O), nucleating agents sodium carbonate 1 as monohydrate _{(Na 2 CO 3 · 1H 2} O) and sodium pyrophosphate 1
It is a heat storage material composition to which 0-hydrate (Na ₄ P ₂ O ₇ · 10H ₂ O) is added.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat storage material composition. More specifically, it reduces the degree of supercooling during solidification,
The present invention relates to a heat storage material composition that exhibits stable nucleating performance at high temperatures during melting.

[0002]

2. Description of the Related Art A large number of organic and inorganic substances have been studied as latent heat storage materials. Among them, sodium acetate trihydrate has a large latent heat at the time of phase change, especially melting and solidification due to the involvement of water molecules in the crystal thereof, and is regarded as a promising heat storage material. However, sodium acetate trihydrate has a large degree of supercooling, and when it is completely melted by heating, it has the property of not easily being supercooled to around 0 ° C. and solidifying. Therefore, a method of preventing supercooling by adding phosphoric acid or anhydrous sodium carbonate as a nucleating agent (Japanese Patent Publication No.
14718 and Japanese Examined Patent Publication No. 3-48238).
Have been proposed. However, even when these nucleating agents have a melting temperature of 80 ° C. or higher, the nucleating effect is lost and supercooling cannot be prevented. Therefore, a nucleating agent for storing heat using a heat source of 80 ° C. or higher has been proposed (JP-B-6).
4-5634 and JP-A-61-57679).

[0003]

In general, when the heat storage material is used for various purposes, it is very important to raise the maximum heating temperature at which the solidification and reproducibility can be increased to improve the reliability of the heat storage system. . The reason is that if the heat storage material is heated above that temperature, the nucleating effect of the nucleating agent will disappear, and therefore the actual operating temperature of the heat storage material must be strictly maintained at a temperature below that. Will not happen. Therefore, if the maximum heating temperature can be raised even a little, the reliability of the heat storage system is improved, and the heat storage system can be used as a high temperature heat source such as waste heat utilization.

[0004]

Means for Solving the Problems The present invention provides "1. sodium acetate trihydrate (CH3COONa.
3H ₂ O), sodium carbonate monohydrate (N
_{a 2 CO 3 · 1H 2 O} ) and the heat storage material composition characterized by the addition of sodium pyrophosphate decahydrate (Na4P2O7 · 10H2O). 2. The heat storage material according to item 1, wherein a composition in which one or more other inorganic salts or inorganic hydrates are added to sodium acetate trihydrate to adjust the melting point is used instead of sodium acetate trihydrate. Composition. 3. The heat storage material composition according to item 1 or 2, wherein sodium carbonate and sodium pyrophosphate are anhydrous salts. 4. The heat storage material composition according to item 1 or 2, wherein the sodium acetate trihydrate is composed of anhydrous sodium acetate and water. 5. The content of the nucleating agent is 100% sodium acetate trihydrate.
The heat storage material composition according to any one of items 1 to 4, which is 1 to 15 parts by weight with respect to parts by weight. 6. The heat storage material composition according to any one of items 1 to 5, wherein the weight ratio of sodium carbonate monohydrate and sodium pyrophosphate decahydrate of the nucleating agent is 1: 9 to 9: 1. 7. Sodium carbonate monohydrate and sodium pyrophosphate 1
7. The nucleating agent having a weight ratio of 0 hydrate of 1: 9 to 9: 1 is blended in an amount of 1 to 15 parts by weight with respect to 100 parts by weight of sodium acetate trihydrate. Thermal storage material composition. Regarding

[0005]

The present inventors applied sodium carbonate monohydrate and sodium pyrophosphate 1 to a sodium acetate trihydrate heat storage material.
It was found that such a problem can be effectively solved by adding 0-hydrate together as a nucleating agent. In addition,
The nucleating agent may be either anhydrous or hydrated. Sodium carbonate monohydrate alone has a melting temperature of about 60 ° C., and sodium pyrophosphate decahydrate alone 80
At a melting temperature of about 0 ° C, it acts as an effective supercooling inhibitor. When it is melted by using waste heat, the melting point may be around 80 ° C, and if sodium carbonate monohydrate and sodium pyrophosphate decahydrate are used alone as a nucleating agent, the nucleating effect is lost. It is expected that. When the sodium acetate-based heat storage material from which the nucleation effect has disappeared is once again solidified, the effect of preventing supercooling can be obtained again. That is, it is considered that sodium carbonate monohydrate and sodium pyrophosphate decahydrate protect the sodium acetate crystals from wrapping so as not to melt. However, it is considered that these nucleating agents are melted at a certain temperature or higher, and the crystals of sodium acetate are not enclosed and the nucleating effect is lost.

Therefore, it has been found that when sodium carbonate monohydrate and sodium pyrophosphate decahydrate are used in combination as a nucleating agent, the solidification is ensured even when the sodium carbonate is melted at 80 ° C to 86 ° C. Compared to using sodium carbonate monohydrate and sodium pyrophosphate decahydrate alone, by using them together, the heat resistance performance is remarkably improved, and a heat storage material that can be used in a heat storage system that uses waste heat is available. Was obtained.
Although the scientific reason for this is not clear, it is considered that the combined use of sodium carbonate monohydrate and sodium pyrophosphate decahydrate enhances the function of protecting the seed crystal sodium acetate from melting.

The total amount of sodium carbonate monohydrate and sodium pyrophosphate decahydrate is 1 part by weight or more, preferably 3 parts by weight or more based on 100 parts by weight of the main component. Even if 15 parts by weight or more is added, the effect obtained does not change, and the latent heat amount of the main component tends to decrease.
The upper limit is 5 parts by weight. The weight ratio of the added amounts of sodium carbonate monohydrate and sodium pyrophosphate decahydrate is 9: 1 to
1 to 9, preferably 3: 7 to 7: 3, and more preferably 4: 6 to 6: 4.

As the sodium acetate trihydrate, it is possible to use a trihydrate salt, or a mixture of anhydrous sodium acetate and at least 1.2 times the amount of water of crystallization.

[0009]

【Example】

Example 1 100 parts by weight of sodium acetate trihydrate and 3 parts by weight of polyglycerin as a phase separation inhibitor were the main components, and the main component 1
Sodium carbonate monohydrate and sodium pyrophosphate decahydrate were added as supercooling inhibitors in the proportions shown in Table 1 with respect to 00 parts by weight. The prepared sample is placed in a glass container having a volume of 100 ml and tightly closed. This was completely melted in a constant temperature water bath at 65 ° C. and vigorously stirred with a paint shaker. Although supercooling breaks and crystallizes even when left at room temperature, a seed crystal of sodium acetate trihydrate was added to the sample in the supercooled state to solidify because the evaluation was performed under the same conditions. Samples are kept at 40 ℃ for 2 hours, 80 ℃, 82 ℃, 84 ℃, 86
It was confirmed whether or not the solidification was repeated by repeating the heat recycling of holding at 2 ° C., 88 ° C. and 90 ° C. for 2 hours. The test results obtained by repeating 5 times were evaluated according to the following criteria. ◯: Nucleation and coagulation were performed with good reproducibility in all cases. Δ: Nucleation effect was sometimes lost. X: Coagulation was not achieved at all. Table 1 shows the experimental results. The temperature of the constant temperature bath is 86 for all samples
It was confirmed that even at ℃, it is sure to nucleate.

[0010]

[Table 1]

Example 2 60 parts by weight of anhydrous sodium acetate, 40 parts by weight of water, and 3 parts by weight of polyglycerin as a phase separation inhibitor were used as main components. And sodium pyrophosphate decahydrate were added as supercooling inhibitors. A sample was prepared in the same manner as in Example 1. The experimental results are shown in Table 2. Sample No. It was confirmed that Nos. 4 and 5 were capable of surely nucleating even when the temperature of the constant temperature bath was 86 ° C.

[0012]

[Table 2]

Example 3 60 parts by weight of anhydrous sodium acetate, 40 parts by weight of water and 3 parts by weight of polyglycerin as a phase separation inhibitor are main components. From Example 2, it has been found that when anhydrous sodium carbonate and sodium pyrophosphate decahydrate are added at a weight ratio of 5: 5 or 6: 4, excellent heat resistance is exhibited.
Samples 1 to 9 have a weight ratio of 5: 5 and 0.5 to 4.5 parts by weight per 100 parts by weight of the main component, and Sample 10 has a weight ratio of 6: 4 and 3 to 100 parts by weight of the main component. A weight part was added and a sample was prepared in the same manner as in Example 1. Table 3 shows the temperature of the constant temperature bath and the test results. It was confirmed that all the samples at 80 ° C., the samples 2 to 10 at 82 ° C., and the samples 7 to 10 at 84 ° C. surely nucleated.

[0014]

[Table 3]

Example 4 100 parts by weight of sodium acetate trihydrate and 3 parts by weight of polyglycerin as a phase separation inhibitor were the main components, and the main component 1
Sodium carbonate monohydrate and anhydrous sodium pyrophosphate were added as supercooling inhibitors in a ratio of Table 4 with respect to 00 parts by weight. A sample was prepared in the same manner as in Example 1. The experimental results are shown in Table 4. It was confirmed that all of the samples were surely nucleated at a temperature of 82 ° C. in a constant temperature bath, but deactivated at 84 ° C. Even if anhydrous sodium pyrophosphate is used, a heat resistance effect of 82 ° C. can be obtained, but it seems that the effect obtained by using sodium pyrophosphate decahydrate as in Examples 1 to 3 is greater.

[0016]

[Table 4]

Comparative Example Table 5 shows the results obtained in the same manner as in Example 1 except that sodium carbonate monohydrate and sodium pyrophosphate decahydrate were not used and other substances were used.

[0018]

[Table 5]

[0019]

INDUSTRIAL APPLICABILITY According to the present invention, by blending sodium acetate trihydrate with sodium carbonate monohydrate and sodium pyrophosphate decahydrate, supercooling is prevented and the action of the nucleating agent is 80 ° C to 86 ° C. Even if it melts at a high temperature of ℃, it has the effect of reliably solidifying.

Claims (7)

[Claims] 1. Sodium acetate trihydrate (CH3COO
The Na · _3H 2 O), the addition of sodium carbonate monohydrate _{(Na 2 CO 3 · 1H 2} O) and sodium pyrophosphate decahydrate _{(Na 4 P 2 O 7 ·} 10H 2 O) as a nucleating agent A heat storage material composition characterized by: 2. A composition having a melting point adjusted by adding one or more other inorganic salts or inorganic hydrate salts to sodium acetate trihydrate instead of sodium acetate trihydrate. The heat storage material composition described in 1. 3. The heat storage material composition as set forth in claim 1 or 2, wherein sodium carbonate and sodium pyrophosphate are anhydrous salts. 4. The heat storage material composition according to claim 1 or 2, wherein the sodium acetate trihydrate is composed of anhydrous sodium acetate and water. 5. The heat storage material composition according to claim 1, wherein the content of the nucleating agent is 1 to 15 parts by weight with respect to 100 parts by weight of sodium acetate trihydrate. . 6. The heat storage according to any one of claims 1 to 5, wherein the weight ratio of the nucleating agent sodium carbonate monohydrate to sodium pyrophosphate decahydrate is 1: 9 to 9: 1. Wood composition. 7. A nucleating agent having a weight ratio of sodium carbonate monohydrate to sodium pyrophosphate decahydrate of 1: 9 to 9: 1 is compounded in an amount of 1 to 15 parts by weight per 100 parts by weight of sodium acetate trihydrate. The heat storage material composition according to any one of claims 1 to 6.