JP2000008029A - Latent heat storage material composition and heat storage method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an economically excellent latent heat material composition not losing a supercooling prevention property even if used repeatedly and having an appropriate temperature range for heat storage. SOLUTION: This composition includes sodium thiosulfate dihydrate in the ratio of 0.02-18 pts.wt. per 100 pts.wt. sodium thiosulfate pentahydrate or sodium thiosulfate semihydrate in the ratio of 0.1-18 pts.wt. per 100 pts.wt. sodium thiosulfate pentahydrate. Alternatively, the composition includes sodium thiosulfate dihydrate in the ratio of 0.02-18 pts.wt. and sodium thiosulfate semihydrate in the ratio of 0.1-18 pts.wt. per 100 pts.wt. sodium thiosulfate pentahydrate (however, the total amount of sodium thiosulfate dihydrate and sodium thiosulfate semihydrate based on 100 pts.wt. sodium thiosulfate pentahydrate is <18 pts.wt.).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latent heat storage material composition suitable for floor heating and heating of a heat pump type air conditioner and a heat storage method using the composition.

[0002]

2. Description of the Related Art A number of methods have heretofore been proposed as methods for providing a nucleation effect for preventing supercooling of a latent heat storage material composition containing sodium thiosulfate pentahydrate as a main component. The following patents and documents are listed.

Japanese Patent Application Laid-Open No. 50-90584 proposes a method of making the supercooling easy to break by increasing the water content from the theoretical value of sodium thiosulfate pentahydrate by showing a phase diagram of sodium thiosulfate. ing.

JP-A-55-120686 and JP-A-55-142077 disclose compositions containing an alkali metal salt or ammonium salt of tetraborate.

JP-A-55-142076 and JP-A-59-115381 disclose compositions containing a sulfate or hydroxide of an alkaline earth metal.

JP-A-53-6285 describes that a mixture of calcium sulfite 1 / 2-hydrate, which is a thermal decomposition product of calcium thiosulfate hexahydrate, and sulfur is effective as a supercooling inhibitor. There is.

JP-A-58-45499, JP-A-5-45499
JP-A-8-52995 describes compositions containing naphthol and naphthalene, respectively.

JP-A-58-79079 and JP-A-5-79079
8-66799 and JP-A-57-149379
The publication describes a method of improving the nucleation property by mixing an organic substance and an inorganic substance, changing the solubility of sodium thiosulfate pentahydrate.

Japanese Patent Laying-Open No. 57-147578 proposes a latent heat storage material composition containing sodium tartrate dihydrate.

[0010]

However, according to the method disclosed in Japanese Patent Application Laid-Open No. 50-90584, the nucleating ability of the composition is extremely weak, and even if a nucleating agent is blended within the described range. But its nucleation is very uncertain.

According to the methods described in JP-A-55-120686 and JP-A-55-142077, sodium sulfate decahydrate, which is one of the oxidation products of sodium thiosulfate pentahydrate, is reliably used. Although it has a strong nucleation effect, it has only a very weak effect on sodium thiosulfate pentahydrate itself.

In the methods described in JP-A-55-142076 and JP-A-59-115381, the nucleating effect of the composition is not yet sufficient.

The method disclosed in Japanese Patent Application Laid-Open No. 53-6285 is described as a nucleation effect due to the charged electric charge, and the nucleation effect is exhibited only once, and after the second time, supercooling occurs. It is reported that "Electrochemistry", p. 550, 53
Vol. 8 (1985).

JP-A-58-45499, JP-A-5-45499
The method disclosed in Japanese Patent Application Laid-Open No. 8-52995 has a drawback in that the substance itself has sublimability, and the function of nucleation is lost within a short period of time due to heat history.

Further, JP-A-58-79079, JP-A-58-66799, and JP-A-57-14937.
In the compositions of JP-A No. 9 and JP-A-57-147578, the nucleation effect is considerably improved by increasing the amount of organic substances and inorganic substances in the composition, but the heat storage temperature decreases in accordance with the blending amount. Problem.

The only literature that discusses sodium thiosulfate pentahydrate as a latent heat storage material is the extent to which the above is present, and the peritectic reaction of sodium thiosulfate pentahydrate is still insufficient. Not only has not been elucidated, has a heat storage temperature in a heat storage temperature zone suitable for humans to heat,
In fact, a latent heat storage material composition using sodium thiosulfate pentahydrate, which is excellent in economy, has not been put to practical use.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a latent heat storage material composition which does not lose its ability to prevent supercooling even when repeatedly used, has a proper heat storage temperature range, and is excellent in economy. It is to provide a heat storage method.

[0018]

Means for Solving the Problems In order to solve the above problems, the heat storage material composition according to the first aspect of the present invention contains 0.02 to 2 parts of sodium thiosulfate dihydrate per 100 parts by weight of sodium thiosulfate pentahydrate. It is characterized by containing 18 parts by weight.

Further, the heat storage material composition of the second invention contains 0.1 to 18 parts by weight of sodium thiosulfate pentahydrate per 100 parts by weight of sodium thiosulfate pentahydrate. It is a feature.

The heat storage material composition according to the third aspect of the present invention comprises 0.02 to 18 parts by weight of sodium thiosulfate dihydrate and 1/2 part of sodium thiosulfate per 100 parts by weight of sodium thiosulfate pentahydrate. 0.1-18 parts by weight of water salt (however,
The total amount of sodium thiosulfate dihydrate and sodium thiosulfate １ ／ hydrate per 100 parts by weight of sodium thiosulfate pentahydrate does not exceed 18 parts by weight). .

Further, the fourth invention is characterized in that the latent heat storage material composition of the first invention is used to store heat in a temperature range from a melting temperature of sodium thiosulfate pentahydrate to 65 ° C. or less. Is a heat storage method.

The fifth invention is characterized in that the latent heat storage material composition of the second invention is used to store heat in a temperature range from a melting temperature of sodium thiosulfate pentahydrate to 75 ° C. or less. Is a heat storage method.

Further, the sixth invention is characterized in that the latent heat storage material composition of the third invention is used to store heat in a temperature range from a melting temperature of sodium thiosulfate pentahydrate to 60 ° C. or less. Is a heat storage method.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below. The first invention comprises sodium thiosulfate pentahydrate and sodium thiosulfate dihydrate, and the sodium thiosulfate 2 is used in an amount of 0.02 to 18% by weight per 100 parts by weight of sodium thiosulfate pentahydrate. Parts, preferably 0.15
It is contained in the range of 10 to 10 parts by weight.

When the content of sodium thiosulfate dihydrate is 0.0
If it is less than 2 parts by weight, it is easily dissolved in sodium thiosulfate pentahydrate in the temperature range for use as a latent heat storage material, and cannot sufficiently exhibit a crystal nucleus forming action for preventing supercooling. Further, even if it exceeds 18 parts by weight, there is no change in the crystal nucleus forming action, and on the contrary, the amount of latent heat storage as the heat storage material composition is reduced, and it is not practical as a latent heat storage material.

Next, a method for easily preparing sodium thiosulfate dihydrate will be described. Anhydrous sodium thiosulfate and water, or anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate were blended in any case in such a ratio as to give sodium thiosulfate 5/2 hydrate, and the upper portion was opened. Put in a container (such as a beaker) and heat while stirring so that the internal temperature becomes 70 to 75 ° C. The stirring is continued as it is, and after all the salt in the container is melted, the solution is cooled to 50 ° C. and the crystallized product is filtered. The product obtained by this operation is sodium thiosulfate dihydrate containing some sodium thiosulfate pentahydrate. Sodium thiosulfate dihydrate itself does not show deliquescence or efflorescence, and its particle size can be adjusted with a crusher or the like to facilitate handling.

In order to obtain the composition of the first aspect of the present invention, such sodium thiosulfate dihydrate may be mixed with sodium thiosulfate pentahydrate in the above-mentioned ratio. In the step of obtaining sodium thiosulfate dihydrate as described above, since water is mixed slightly more than the equivalent amount to manufacture, the sodium thiosulfate pentahydrate is slightly contained. Needless to say, it is blended.

It is also possible to increase the amount of water so that sodium thiosulfate pentahydrate is contained in excess.
In this case, if the ratio of sodium thiosulfate pentahydrate and sodium thiosulfate dihydrate is adjusted as described above, the composition of the first invention of the present application can be obtained in one step.

According to the second invention, sodium thiosulfate pentahydrate is blended with sodium thiosulfate pentahydrate, and sodium thiosulfate pentahydrate is added per 100 parts by weight of sodium thiosulfate pentahydrate. 0.1 to 18 parts by weight, preferably 0.14 to 9 parts by weight.

When the content of sodium thiosulfate 水 -hydrate is less than 0.02 parts by weight, it is easily dissolved in sodium thiosulfate pentahydrate in the temperature range of use as a latent heat storage material, so that supercooling can be prevented. Nucleation effect cannot be sufficiently exhibited. Further, even if it exceeds 18 parts by weight, there is no change in the crystal nucleus forming action, and on the contrary, the amount of latent heat storage as the composition is reduced, and it is not practical as a latent heat storage material.

Next, a method for easily preparing sodium thiosulfate 1 / 2-hydrate will be described. A mixture of anhydrous sodium thiosulfate and water, or anhydrous sodium thiosulfate and sodium thiosulfate pentahydrate in any case to the extent of sodium thiosulfate dihydrate as a whole, and a container with an open top (such as a beaker) Things). Heat with stirring so that the internal temperature is 83-88 ° C.
If the stirring is continued as it is, the water inside the container is volatilized to form a slurry. Sodium thiosulfate 1 containing some sodium thiosulfate dihydrate was obtained by this operation.
/ 2 water salt. Sodium thiosulfate 1/2 water salt itself does not show deliquescence or efflorescence, and has sufficient functions as a nucleating agent as it is. However, in order to facilitate handling such as particle size adjustment, The purity of the sodium thiosulfate half-hydrate may be increased by air drying such as by extending the heating time.

Unlike the case of sodium thiosulfate dihydrate described above, if the amount of water is slightly larger than the amount (equivalent) to become a half-hydrate, the amount of water is too small to perform sufficient stirring. It is preferable to volatilize the water after using excess water.

In order to obtain the composition of the second aspect of the present invention, such sodium thiosulfate １ ／ -hydrate may be blended with sodium thiosulfate pentahydrate in the above ratio. When sodium thiosulfate 水 hydrate containing sodium thiosulfate dihydrate is used as described above, the solubility at a temperature lower than the melting point of the original sodium thiosulfate 水 hydrate increases, and nuclei due to heat history. It is preferable to use purified sodium thiosulfate 水 -hydrate because the formability is likely to decrease. However, for example, if the heat storage and release is performed at 65 ° C. or less, sodium thiosulfate dihydrate becomes sodium thiosulfate. If it is less than 25% of 1/2 water salt, there is no practical problem as a latent heat storage material composition.

In the first invention or the second invention,
It is preferable to add water to the latent heat storage material composition because the nucleation property is further improved, but sodium thiosulfate pentahydrate 100
If the amount of water per part by weight exceeds 7 parts by weight, various properties as a latent heat storage material are reduced. Therefore, it is preferable to add the water in an amount of 7 parts by weight or less, more preferably 100 parts by weight of sodium thiosulfate pentahydrate. 1 to 7 parts by weight.

In the third invention, sodium thiosulfate pentahydrate and sodium thiosulfate dihydrate and sodium thiosulfate 1
/ 2 water salt, sodium thiosulfate 5
0.02 to 18 parts by weight of sodium thiosulfate dihydrate and 100 parts by weight of sodium salt,
0.1 to 18 parts by weight of dihydrate (however, the total amount of sodium thiosulfate dihydrate and sodium thiosulfate １ ／ hydrate per 100 parts by weight of sodium thiosulfate pentahydrate does not exceed 18 parts by weight ), Preferably 0.15 to 10 parts by weight of sodium thiosulfate dihydrate and 0.14 to 9 parts by weight of sodium thiosulfate １ ／ (100% sodium thiosulfate pentahydrate) (The total amount of sodium thiosulfate dihydrate and sodium thiosulfate 水 hydrate per part by weight does not exceed 10 parts by weight).

When the contents of sodium thiosulfate dihydrate and sodium thiosulfate 水 hydrate are less than 0.02 and 0.1 parts by weight, respectively, sodium thiosulfate pentahydrate is used in the temperature range for use as a latent heat storage material. It is easy to dissolve in salt and cannot sufficiently exhibit the crystal nucleus forming action for preventing supercooling. Although the crystal nucleus forming action does not change even if each exceeds 18 parts by weight, the amount of latent heat storage as a composition is rather lowered, and is not practical as a latent heat storage material.

The method for easily preparing sodium thiosulfate dihydrate and sodium thiosulfate 1/2 water salt is as described above.

In order to obtain the composition of the third invention, such sodium thiosulfate dihydrate and sodium thiosulfate 1 /
The dihydrate may be added to the sodium thiosulfate pentahydrate in the above proportion.

When a mixture of sodium thiosulfate dihydrate and sodium thiosulfate 水 -hydrate is used as described above, the melting point of the original sodium thiosulfate dihydrate or sodium thiosulfate 水 -hydrate is reduced. The nucleation ability tends to decrease due to the heat history due to the increase in the solubility at the temperature, but there is no practical problem as a latent heat storage material composition, for example, when the heat storage and release are performed at 60 ° C. or less.

In the first to third inventions, in addition to the above, mercury iodide, amyl alcohol, chloroform, borax, sodium benzoate, etc., which are known as antioxidants of sodium thiosulfate, are used in the present invention. It is also possible to prevent oxidation by adding an appropriate amount as desired within a range not to impair the purpose. In addition, in the first to third inventions, known nucleating agents (supercooling inhibitors), phase separation inhibitors, calorific stabilizers such as surfactants, etc. do not impair the object of the present invention. It is also possible to mix an appropriate amount within the range as desired.

Next, the fourth to sixth inventions will be described. First, the concept of heat storage so far will be described. Originally, in a latent heat storage material composition utilizing a hydration reaction, it is a matter to be avoided to mix a lower salt of the heat storage base material. This is because in the hydration reaction that reciprocates between the solid phase and the liquid phase, the coordination state of the water molecules interposed around the salt is assumed to change during the hydration reaction. This is because it is generally considered to change to a more stable hydrated salt (for example, the highest order hydrated salt and anhydrous salt).

Although the tendency is likely to be seen in sodium thiosulfate dihydrate and sodium thiosulfate 水 -hydrate, in the fourth to sixth inventions, sodium thiosulfate pentahydrate to sodium thiosulfate pentahydrate is used. It is characterized in that the dissolved amount of water salt and / or sodium thiosulfate 1/2 water salt is made very small.

That is, in the fourth to sixth inventions, sodium thiosulfate dihydrate and / or sodium thiosulfate 1
/ 2 hydrate dissolves in sodium thiosulfate pentahydrate at the time of heat storage, but its amount is very small, and sodium thiosulfate dihydrate and / or sodium thiosulfate 1 / Dihydrates are more stable anhydrous salts and 5
The used sodium thiosulfate dihydrate and / or sodium thiosulfate 1/2
Most of the water salt remains undissolved in the composition, so that the nucleation ability is not reduced even by a long-term heat history.

The fourth invention uses the latent heat storage material composition of the first invention to store heat in a temperature range from the melting temperature of sodium thiosulfate pentahydrate to 65 ° C. or less. The reason will be described with reference to FIG.

FIG. 1 is a curve showing the solubility of sodium thiosulfate dihydrate in sodium thiosulfate pentahydrate. The vertical axis indicates the solubility of sodium thiosulfate dihydrate, and the horizontal axis indicates the temperature of the composition.

Since the main component of the heat storage material is sodium thiosulfate pentahydrate, the heat storage may be performed at a temperature higher than the melting temperature of sodium thiosulfate pentahydrate. As is apparent from FIG. The solubility of sodium thiosulfate dihydrate in sodium thiosulfate pentahydrate rapidly increases,
Sodium thiosulfate 2 in the composition due to long term heat history
The nucleation ability decreases due to a decrease in water salt.

The fifth invention uses the latent heat storage material composition of the second invention to store heat in a temperature range from the melting temperature of sodium thiosulfate pentahydrate to 75 ° C. or less. The reason is the same as in the case of the fourth invention, and can be explained based on FIG.

FIG. 2 is a curve showing the solubility of sodium thiosulfate 水 hydrate in sodium thiosulfate pentahydrate. In the fifth invention, the main component as the heat storage material is sodium thiosulfate pentahydrate. The heat storage may be carried out at a temperature higher than the melting temperature of sodium thiosulfate pentahydrate. As is apparent from FIG.
The solubility of the hydrate in sodium thiosulfate pentahydrate rapidly increases, and the long-term heat history causes the sodium thiosulfate 水 -hydrate in the composition to decrease and the nucleation ability to decrease.

As described above, sodium thiosulfate 1 /
The dihydrate may be used as containing some sodium thiosulfate dihydrate. In this case, the solubility in sodium thiosulfate pentahydrate tends to increase slightly even at a temperature lower than 75 ° C. In the fifth aspect of the present invention, the heat is preferably stored at 65 ° C. or lower.

The sixth aspect of the present invention is a method for storing and releasing heat using the latent heat storage material composition of the third aspect of the present invention in a temperature range from the melting temperature of sodium thiosulfate pentahydrate to 60 ° C. or less. .

Since the main agent as the heat storage material is sodium thiosulfate pentahydrate, the heat storage may be performed at a temperature equal to or higher than the melting temperature of sodium thiosulfate pentahydrate. Sodium thiosulfate 1 /
The solubility of dihydrate in sodium thiosulfate pentahydrate sharply increases, and sodium thiosulfate dihydrate and sodium thiosulfate 水 hydrate in the composition decrease due to long-term heat history, resulting in a decrease in nucleation ability. I do. Therefore, heat storage is performed at 60 ° C. or less.

[0052]

Hereinafter, the present invention will be described based on examples.
The present invention is not limited to these examples. In addition, all the units of the formulation shown in the following tables are parts by weight.

Examples 1 to 27 and Comparative Examples 1 to 14 The various samples used in this example were prepared from the following samples to prepare the latent heat storage material compositions for each test according to the formulation shown in each table. did. Sample 1: Sodium thiosulfate pentahydrate Sample 2: Sodium thiosulfate dihydrate Sample 3: Sodium thiosulfate 水 hydrate Sample 4: Water Sample 5: Sodium tetraborate decahydrate Sample 6: Magnesium hydroxide 6 Water salt Sample 7: Sodium sulfite 1/2 water salt Sample 8: Naphthalene Sample 9: Salt Sample 10: Ethyl alcohol Sample 11: p-oxybenzoic acid

[Test for measuring heat storage temperature of latent heat storage material composition]
The internal temperature of the heat storage material composition at a depth of 1.5 cm from the surface of the latent heat storage material (2 samples) was measured using the solidification temperature measurement method of JIS K 0065 chemical product for the measurement of the heat storage temperature.

[Measurement test of heat storage amount of latent heat storage material composition] The latent heat storage amount of the latent heat storage material was defined and measured as follows. Basically, a "mixing method" used for measuring specific heat in a physical experiment or the like was used. In principle, the latent heat storage material composition sealed in the container is melted and stored at a certain temperature. Thereafter, the sample is placed in an insulated water tank containing water adjusted to a temperature around room temperature, and the water is sufficiently coagulated and radiated. When the heat is sufficiently transferred to the water, the temperature of the water inside the water tank rises. Therefore, the product of the temperature rise, the specific heat of the water and the weight of the water is defined as the latent heat storage amount of the heat storage material composition.

The details are as follows. 120 made of nylon-polyethylene film (thickness 30 μm)
A bag having a size of mm × 90 mm was prepared. 80 g of each heat storage material composition was put therein, and the weight was measured. This is 53
Heat was stored in a constant temperature water bath at ± 0.5 ° C. for 2 hours.

1500 g of cold water (4 ± 1 ° C.) was weighed
The sample after the above-mentioned heat storage was put into a liter capacity dewar, and the temperature change of the cold water inside the dewar was measured and recorded by a thermometer with a precision of 1/100 ° C., and the time when the same temperature continued for 20 minutes or more was measured. The end point. The formula for calculating the latent heat storage amount was as follows. Q: Latent heat storage amount (cal / g) S: Weight of heat storage material composition (g) W: Weight of water inside dewar bottle (g) W ': Water equivalent Cpl: Specific heat of liquid of heat storage material composition (cal / g ·) ° C) Cps: Specific heat of solid of heat storage material composition (cal / g · ° C) T0: Initial temperature of heat storage material composition (53 ± 0.5 ° C) T1: Initial water temperature inside dewar bottle (4 ± 1 ° C) T2 : Final water temperature inside dewar (° C) T3: Heat storage temperature of heat storage material composition (° C)

[Heat History Test of Latent Heat Storage Material Composition (Nucleation Forming Test)] The latent heat storage material composition sealed in a nylon-polyethylene film bag similar to the heat storage amount measurement test was used.
I prepared them. After heat storage at 60 ° C. for 4 hours, each of the above 10 samples was placed in a chamber-type constant temperature bath capable of performing a program operation in which heat release at 20 ° C. for 4 hours was performed in one cycle, and 30 cycles were given to the latent heat storage material. After the first cycle and 3
After the 0th cycle, the number of samples solidified by heat radiation was visually observed. The obtained results are shown in Tables 1 to 7 below.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

[0063]

[Table 5]

[0064]

[Table 6]

[0065]

[Table 7]

[0066]

According to the present invention, sodium thiosulfate pentahydrate, which has a heat storage temperature in a heat storage temperature zone suitable for human warming and is economical, can be used even after a long-term heat history. An object of the present invention is to provide a latent heat storage material composition and a heat storage method that do not hinder practical use.

[Brief description of the drawings]

FIG. 1 is a solubility curve of sodium thiosulfate dihydrate in sodium thiosulfate pentahydrate.

FIG. 2 is a solubility curve of sodium thiosulfate 水 hydrate in sodium thiosulfate pentahydrate.

Claims (6)

[Claims] 1. A latent heat storage material composition comprising 0.02 to 18 parts by weight of sodium thiosulfate dihydrate per 100 parts by weight of sodium thiosulfate pentahydrate. 2. 0.1 to 18 parts of sodium thiosulfate hydrate per 100 parts by weight of sodium thiosulfate pentahydrate.
A latent heat storage material composition, which is contained in a ratio of parts by weight. 3. 0.02 to 18 parts by weight of sodium thiosulfate dihydrate and 0.1 to 0.1 parts by weight of sodium thiosulfate 水 per 100 parts by weight of sodium thiosulfate pentahydrate.
18 parts by weight (however, the total amount of sodium thiosulfate dihydrate and sodium thiosulfate １ ／ hydrate per 100 parts by weight of sodium thiosulfate pentahydrate does not exceed 18 parts by weight). A latent heat storage material composition. 4. A heat storage method comprising using the latent heat storage material composition according to claim 1 to store heat in a temperature range from a melting temperature of sodium thiosulfate pentahydrate to 65 ° C. or less. . 5. A heat storage method comprising using the latent heat storage material composition according to claim 2 to store heat in a temperature range from a melting temperature of sodium thiosulfate pentahydrate to 75 ° C. or less. . 6. A heat storage method using the latent heat storage material composition according to claim 3 to store heat in a temperature range from a melting temperature of sodium thiosulfate pentahydrate to 60 ° C. or less. .