JP7266282B2 - Heat storage material composition - Google Patents

Description

The present invention relates to a heat storage material composition.

Conventionally, heat storage materials (latent heat storage materials, sensible heat storage materials) that store heat (heat absorption) and release heat (heat release) by utilizing the phase change between solid and liquid (solid-liquid phase change) in a predetermined temperature range materials, heat storage materials, etc.) are known. Heat storage materials are widely used in various fields, for example, air-conditioning equipment for buildings (houses, office buildings, etc.) that require a large amount of cold heat and heat, and exhaust heat recovery equipment for factories.

As a technique related to the heat storage material, for example, Japanese Patent Application Laid-Open No. 11-323319 (Patent Document 1) discloses that sodium acetate trihydrate is added with hydrophilic fumed silica, hydrophilic fumed alumina and calcium salt as phase separation inhibitors. A compounded latent heat storage material composition is disclosed. As a result, even if the heat cycle of melting and solidification is repeated over a long period of time, phase separation does not occur.

Further, Japanese Patent Application Laid-Open No. 2000-63810 (Patent Document 2) describes 100 parts by weight of calcium chloride hydrate having a composition of the general formula CaCl ₂ ·nH ₂ O (where n is 4.5 to 6.5). 10 to 35 parts by weight of a polyhydric alcohol, 1 to 30 parts by weight of one or more halides of alkali metals and alkaline earth metals (excluding strontium chloride and barium chloride), strontium chloride and/or Alternatively, the latent heat obtained by mixing 0.1 to 20 parts by weight of barium chloride and, if necessary, 0.1 to 20 parts by weight of one or more fibrous minerals such as attapulgite, wollastonite, and sepiolite. A thermal storage material composition is disclosed. As a result, the freezing point is in the relatively low temperature range (5 to 25°C), and it is said that it can be used as a heat storage material for air conditioning cooling and heating systems.

In addition, in JP-A-2015-218212 (Patent Document 3), a latent heat storage material (a) is the main component, and a melting point adjuster (b) has a fine crystal formation action, a supercooling prevention action, and a thickening action. A latent heat storage material composition containing a predetermined amount of a phase separation inhibitor (c) and/or a melting point adjuster (b') having a fine crystal forming action and a supercooling inhibitor (d) as essential components, the latent heat storage material composition comprising: A latent heat storage material composition obtained by blending a substance with a melting point adjuster, a phase separation inhibitor, and a supercooling inhibitor in predetermined amounts and melt-mixing and cooling the mixture is disclosed. As a result, it is composed mainly of aggregates of fine particles that are flexible or fluid under normal temperature and pressure, does not undergo phase separation, does not cause supercooling, and provides excellent heat storage and heat dissipation stably. It is said that it can be used as a heat transfer medium that can be repeated and flowable.

Further, Japanese Patent Application Laid-Open No. 2016-108535 (Patent Document 4) contains a sugar alcohol and a supercooling stabilizer, and the supercooling stabilizer (i) has a solubility in 100 mL of water at 20 ° C. 9 g or more and a salt that is a monovalent anion, (ii) a polymer containing a salt as a monomer, or (iii) an alcohol having a solubility of 9 g or more in 100 mL of water at 20°C as a monomer, 7000 to 400 A heat storage material composition is disclosed that is a polymer having a molecular weight of 10,000. As a result, the supercooled state can be stably maintained at room temperature or a temperature close to room temperature.

For example, the present applicant discloses a heat storage material composition containing calcium chloride as a main component and containing strontium chloride and barium chloride as nucleating materials in Retable 2007/099798 (Patent Document 5). and a heat storage material composition containing a cellulosic material as a thickener. As a result, even under conditions where it is repeatedly exposed to high temperatures exceeding room temperature, it is difficult to deteriorate and has high durability and heat resistance.

JP-A-11-323319 JP-A-2000-63810 JP 2015-218212 A JP 2016-108535 A Retable 2007/099798

In the heat storage material composition using the solid-liquid phase change described above, the thermal conductivity is generally low as a whole, so it is difficult to quickly store heat from the surrounding environment and release heat to the surrounding environment, and it takes time to store and release heat. There is a problem of hanging. Therefore, in order to compensate for the low thermal conductivity of the heat storage material composition, for example, measures are taken to increase the surface area of the heat storage material composition with respect to the surrounding environment by housing the heat storage material composition in a container with a large surface area. However, in this case, there is a problem that the shape of the container is limited.

On the other hand, as a method for increasing the thermal conductivity, a method of adding particles having a high thermal conductivity is conceivable. There is a problem of precipitation.

These problems cannot be solved by the techniques described in Patent Documents 1 to 5 mentioned above.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a heat storage material composition that enables rapid heat storage and heat release, and that can be stably and repeatedly used. do.

The heat storage material composition according to the present invention includes a solid-liquid phase change material that undergoes a phase change between a solid and a liquid within a predetermined temperature range, water, a nucleating material containing strontium chloride as a main component, and graphite powder. and The concentration of the graphite powder is 1.0% by weight to 10.0% by weight with respect to the total heat storage material composition. Further, the heat storage material composition according to the present invention includes a solid-liquid phase change material that undergoes a phase change between a solid and a liquid within a predetermined temperature range, water, and a nucleating material containing strontium chloride as a main component, It contains graphite powder and a hydrophilic thickener. Further, the concentration of the thickening agent is 0.1% by weight to 5.0% by weight with respect to the total heat storage material composition.

According to the present invention, rapid solid-liquid phase change is realized, and repeated use becomes possible.

1 is a component table of heat storage material compositions of Examples 1-4 and Comparative Example 1. FIG. 5 is a graph of temperature changes of the heat storage material compositions of Examples 1-4 and Comparative Example 1 in the fifth heat cycle. 5 is a component table of heat storage material compositions of Examples 5 to 8 and Comparative Example 1. FIG. 5 is a graph of temperature changes of the heat storage material compositions of Examples 5 to 8 and Comparative Example 1 in the fifth heat cycle. 5 is a graph of temperature changes of the heat storage material compositions of Examples 5 to 8 and Comparative Example 1 in the 26th heat cycle. 2 is a component table of heat storage material compositions of Examples 9 to 12 and Comparative Example 1. FIG. 10 is a graph of temperature changes of the heat storage material compositions of Examples 9 to 12 and Comparative Example 1 in the fifth heat cycle. 10 is a graph of temperature changes of the heat storage material compositions of Examples 9 to 12 and Comparative Example 1 in the 10th heat cycle. 1 is a component table of heat storage material compositions of Examples 13 and 14 and Comparative Example 1. FIG. 10 is a graph of temperature changes of the heat storage material compositions of Examples 13 and 14 and Comparative Example 1 in the fifteenth heat cycle. Photographs of the test tube at the initial stage before the heat cycle, after the 55th heat cycle, and after the 120th heat cycle in Example 13, and at the initial stage before the heat cycle, after the 30th heat cycle, and after the 80th heat cycle in Example 14. It is a test tube photograph after the cycle. 4 is a component table of a heat storage material composition of Comparative Examples 1-5. 5 is a graph of temperature change of the heat storage material composition of Comparative Example 1-5 in the first heat cycle. 10 is a graph of temperature change of the heat storage material composition of Comparative Example 1-5 in the fifth heat cycle.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. It should be noted that the following embodiment is an example that embodies the present invention, and is not intended to limit the technical scope of the present invention.

In a typical heat storage material composition containing a solid-liquid phase change material that undergoes a phase change between a solid and a liquid within a predetermined temperature range, water, and a nucleating material containing strontium chloride as a main component, heat Due to its low conductivity, the rate of heat storage and heat release was low. In addition, even if particles with high thermal conductivity are added, since the specific gravity of the heat storage material composition (aqueous solution) differs from the specific gravity of the particles, the particles immediately precipitate after addition, improving the thermal conductivity of the heat storage material composition. did not connect to

The inventor of the present invention has been researching the above-mentioned heat storage material composition for many years, and has found that the specific gravity of the heat storage material composition (aqueous solution) is about 1.5, and that graphite is a material having a thermal conductivity surpassing that of metals. [The thermal conductivity of graphite is about 2000 W / (m K), the thermal conductivity of copper is about 400 W / (m / K)], and the specific gravity of graphite powder is about 2.0. The present invention was completed based on the examples described later.

That is, the heat storage material composition according to the present invention includes a solid-liquid phase change material that undergoes a phase change between a solid and a liquid within a predetermined temperature range, water, and a nucleating material containing strontium chloride as a main component, graphite powder. As a result, it is possible to quickly store and release heat, and to use it stably and repeatedly.

That is, since the specific gravity of the graphite powder is close to the specific gravity of the heat storage material composition, when the graphite powder is added to the heat storage material composition, the graphite powder is uniformly dispersed in the heat storage material composition, and the entire heat storage material composition is heat conductive. increase rate. As described above, the thermal conductivity of graphite powder is so high that it surpasses that of metals, so that the thermal storage material composition accelerates the rate of heat storage and heat release.

In the case of other thermally conductive powders such as triiron tetroxide (Fe ₃ O ₄ ), the specific gravity of the thermally conductive powder is far from the specific gravity of the heat storage material composition. There is no effect to improve the speed of

In addition, in a heat cycle in which a high temperature (about 60°C) is lowered to a low temperature (about 0°C) and then raised to a high temperature again, even if the heat storage material composition is repeatedly melted and solidified, the graphite powder transforms into a solid-liquid phase change material. It acts as a medium for heat conduction, stably stores and releases heat from the heat storage material composition, and suppresses supercooling. Therefore, long-term repeated use is also possible.

Here, the type of solid-liquid phase change material is not particularly limited, but examples thereof include calcium chloride, sodium acetate, and sodium hydrogen phosphate. Calcium chloride is a component that undergoes a phase change between calcium chloride hexahydrate crystals (solid) and calcium chloride water liquid (liquid) in the heat storage material composition as the temperature of the surrounding environment changes. be. Anhydride (CaCl ₂ ) or its hydrate {CaCl ₂ ·nH ₂ O (n=1 to 6)} can be used as the calcium chloride of the heat storage material composition. In particular, calcium chloride dihydrate is relatively readily available and preferred. The amount of water added to the heat storage material composition is the amount necessary for producing calcium chloride hexahydrate, and may vary slightly due to changes in the amount of water caused by the addition of other components. is about 6 mol for _CaCl2 . Also, when a hydrate is used as calcium chloride, the amount of water is about 6 mol including the water of crystallization in the hydrate.

Other solid-liquid phase change materials also undergo a phase change similar to that of calcium chloride within a predetermined temperature range, and cause heat storage and heat dissipation, although the phase change temperature range is different. These types of solid-liquid phase change materials may be combined as appropriate.

Further, the nucleating material is mainly composed of strontium chloride as described above. Here, the nucleating material may contain components other than strontium chloride, such as barium chloride and barium sulfide. In particular, when strontium chloride, barium chloride, and barium sulfide are contained, for example, their anhydrides (SrCl ₂ ·BaCl ₂ ·BaS) may be used, or hydrates of these compounds may be used. Further, disodium hydrogen phosphate dodecahydrate (Na ₂ HPO ₄ .12H ₂ O) and fly ash may be contained as other nucleating materials.

Here, the type of graphite in the graphite powder is not particularly limited. A carbon nanotube etc. can be mentioned. Further, the graphite powder is preferably subjected to a hydrophilic surface treatment in order to improve its dispersibility in an aqueous solution containing a solid-liquid phase change material. These types of graphite powder may be combined as appropriate.

The average particle size of the graphite powder is not particularly limited, but for example, the average particle size is preferably 5 μm to 20 μm, more preferably 5 μm to 15 μm.

Also, the higher the concentration of the graphite powder, the more the graphite powder in the heat storage material composition comes into contact with each other to form a graphite powder network, which increases the thermal conductivity of the entire heat storage material composition. If the powder concentration is too high, it interferes with the melting and solidification of the solid-liquid phase change material. Therefore, for example, the concentration of graphite powder is preferably 1% by weight to 10% by weight with respect to the total heat storage material composition.

Further, the heat storage material composition according to the present invention includes a solid-liquid phase change material that undergoes a phase change between a solid and a liquid within a predetermined temperature range, water, and a nucleating material containing strontium chloride as a main component, It contains graphite powder and a hydrophilic thickener. Thus, by adding a hydrophilic thickener, it becomes compatible with water in the heat storage material composition, increases the viscosity of the entire heat storage material composition, and increases the specific gravity of the heat storage material composition and the specific gravity of the graphite powder. Even if there is a large difference, segregation of the graphite powder in the heat storage material composition can be suppressed, and the graphite powder can be fixed in a state of being dispersed throughout. Therefore, the thermal conductivity of the entire heat storage material composition can be kept high, the solid-liquid phase change of the solid-liquid phase change material is accelerated, and the melting and solidification speeds of the solid-liquid phase change material are accelerated.

Here, the type of thickening agent is not particularly limited as long as it is hydrophilic. , hydroxypropyl methylcellulose, cellulose derivatives, cellulose nanofibers, carboxyvinyl polymer, acrylic acid/methacrylate alkyl copolymer, cross-linked acrylic acid-based water-soluble polymers such as polyacrylates, xanthan gum, dutan gum, polysaccharides, polyacryl sodium phosphate, finely powdered silica, silica flour, finely powdered diatomaceous earth, glycerin, agar, and the like. These types of thickeners may be combined as appropriate.

In addition, since the thickener has an affinity with water in the heat storage material composition to form a network and increase the viscosity, the effect is obtained even at a low concentration of the thickener. If it is too large, it will hinder the melting and solidification of the solid-liquid phase change material. Therefore, for example, the concentration of the thickening agent is preferably 0.1% by weight to 3.0% by weight, more preferably 0.1% by weight to 2.0% by weight, with respect to the total heat storage material composition. preferable.

Further, a melting point adjusting material is appropriately added to the heat storage material composition, if necessary. Here, the melting point adjuster means a depressant that lowers the freezing point (melting point) of _the solid-liquid phase change material and changes the latent heat generation temperature. ₄ Cl) and the like. Specifically, the latent heat generation temperature of calcium chloride hexahydrate is about 30°C of its freezing point. You may want to lower the temperature to below °C. In such a case, by adding a melting point adjusting material to the heat storage material composition, the freezing point of the solid-liquid phase change material of the heat storage material composition can be intentionally lowered to match the purpose of use of the heat storage material. . There is no particular limitation on the concentration of the melting point adjusting material, and for example, it is set to 1.0% by weight to 20.0% by weight with respect to the total heat storage material composition.

The method of using the heat storage material composition is not particularly limited, but for example, a method of filling and sealing the heat storage material composition in a container and using it as the heat storage material can be mentioned. Since the thermal conductivity of the heat storage material composition is high, there is no particular limitation on the shape of the container, and for example, the shape of the container may be plate-shaped, cylindrical, or the like, and the design can be changed as appropriate according to the application.

In addition, there is no particular limitation on the use of the heat storage material composition, for example, it is used as a heat storage material for cooling and heating equipment, exhaust heat recovery equipment in factories, agricultural equipment such as vinyl greenhouses, electronic equipment such as terminal devices and mobile terminal devices. can do As a method of using the heat storage material, it is possible to effectively utilize thermal energy by storing heat from the surrounding environment during the daytime and dissipating the heat to the surrounding environment at nighttime.

EXAMPLES Examples and comparative examples of the present invention will be specifically described below, but the application of the present invention is not limited to these examples.

<Example 1>
50.7% by weight of solid-liquid phase change material (calcium chloride dihydrate) (CaCl ₂ 2H ₂ O), 10.0% by weight of melting point modifier (ammonium bromide) (NH ₄ Br), water Adjusted to 24.0% by weight, 14.2% by weight of nucleating material mainly containing strontium chloride (SrCl ₂ ), and 1.0% by weight of graphite powder (average particle size 10.3 μm, flake graphite A) The resulting heat storage material composition was used as the heat storage material composition of Example 1. The freezing point (melting point) of the heat storage material composition was set to 18° C. by adding the melting point adjuster.

<Example 2>
In the heat storage material composition of Example 1, the concentration of the melting point adjuster was fixed, the proportions of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the graphite powder was 3.0% by weight. A heat storage material composition of Example 2 was prepared in the same manner as in Example 1 except that the heat storage material composition was changed to .

<Example 3>
In the heat storage material composition of Example 1, the concentration of the melting point adjuster was fixed, the proportions of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the graphite powder was 5.0% by weight. A heat storage material composition of Example 3 was prepared in the same manner as in Example 1 except that the heat storage material composition was changed to .

<Example 4>
In the heat storage material composition of Example 1, the concentration of the melting point adjuster was fixed, the proportions of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the graphite powder was 10.0% by weight. A heat storage material composition of Example 4 was prepared in the same manner as in Example 1 except that the heat storage material composition was changed to .

<Comparative Example 1>
In the heat storage material composition of Example 1, the concentration of the melting point adjuster was fixed, the ratio of the solid-liquid phase change material, water, and nucleation material was the same, and graphite powder was not added. A heat storage material composition prepared in the same manner as in Example 1 was used as a heat storage material composition of Comparative Example 1. 1 shows a component table of the heat storage material compositions of Examples 1 to 4 and Comparative Example 1. As shown in FIG.

<Evaluation method>
For the heat storage material compositions of Examples 1-4 and Comparative Example 1, after the ambient temperature of each heat storage material composition was lowered from about 60°C to about 0°C for a predetermined time (cooling), it was again cooled from about 0°C. The temperature change of each heat storage material composition was measured by repeating a predetermined number of heat cycles in which the temperature was raised to 60°C (heating).

<Evaluation results>
FIG. 2 shows a graph of temperature changes of the heat storage material compositions of Examples 1-4 and Comparative Example 1 in the fifth heat cycle. As shown in FIG. 2, in the cooling of the heat cycle, the heat storage material composition of Example 1-4 has a higher cooling temperature per unit time than the heat storage material composition of Comparative Example 1, and the cooling rate is is faster. Furthermore, it is understood that the higher the concentration of the graphite powder, the steeper the slope of the graph showing the cooling rate.

Also, in the heat storage material composition of Comparative Example 1, the supercooling phenomenon appears in cooling to the ambient temperature, whereas in the heat storage material composition of Examples 1-4, the supercooling phenomenon is suppressed. is understood. It is also understood that the higher the graphite powder concentration, the smoother the peak indicating the supercooling phenomenon.

On the other hand, at the time of heating in the heat cycle, the heat storage material composition of Example 1-4 had a higher heating temperature per unit time and a faster heating rate than the heat storage material composition of Comparative Example 1, and the graph It is understood that the rise of the Furthermore, it is understood that the higher the concentration of the graphite powder, the earlier the graph rises.

<Example 5>
49.9% by weight of solid-liquid phase change material (calcium chloride dihydrate) (CaCl ₂ 2H ₂ O), 10.0% by weight of melting point modifier (ammonium bromide) (NH ₄ Br), water 23.6% by weight, 14.0% by weight of a nucleating agent containing mainly strontium chloride (SrCl ₂ ), 1.0% by weight of graphite powder (average particle size 10.3 μm, flake graphite A), hydrophilic A heat storage material composition of Example 1 was prepared by adding 1.5% by weight of a thickener (a water-soluble copolymer of PEG/PPG, polymer A). The freezing point (melting point) of the heat storage material composition was set to 18° C. by adding the melting point adjuster.

<Example 6>
In the heat storage material composition of Example 5, the concentration of the melting point adjuster was fixed, the proportions of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the graphite powder was 3.0% by weight. A heat storage material composition of Example 6 was prepared in the same manner as in Example 5 except that the heat storage material composition was changed to .

<Example 7>
In the heat storage material composition of Example 5, the concentration of the melting point adjuster was fixed, the proportions of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the graphite powder was 5.0% by weight. A heat storage material composition of Example 7 was prepared in the same manner as in Example 5 except that the heat storage material composition was changed to .

<Example 8>
In the heat storage material composition of Example 5, the concentration of the melting point adjuster was fixed, the proportions of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the graphite powder was 10.0% by weight. A heat storage material composition of Example 8 was prepared in the same manner as in Example 5 except that the heat storage material composition was changed to . 3 shows a component table of the heat storage material compositions of Examples 5 to 8 and Comparative Example 1. As shown in FIG.

<Evaluation method>
For the heat storage material compositions of Examples 5 to 8 and Comparative Example 1, the temperature change of each heat storage material composition was measured by repeating the heat cycle a predetermined number of times in the same manner as described above.

<Evaluation results>
FIG. 4 shows a graph of temperature changes of the heat storage material compositions of Examples 5 to 8 and Comparative Example 1 in the fifth heat cycle. As shown in FIG. 4, in the cooling of the heat cycle, the heat storage material composition of Examples 5-8 has a faster cooling rate than the heat storage material composition of Comparative Example 1, and the supercooling phenomenon does not occur. It was confirmed that it was suppressed. In addition, it was confirmed that the heat storage material composition of Examples 5-8 had a faster heating rate than the heat storage material composition of Comparative Example 1, and that the graph rose quickly during heating in the heat cycle. rice field. In particular, the addition of the hydrophilic thickener improved the cooling rate, suppressed the supercooling phenomenon, and improved the heating rate compared to the case where the hydrophilic thickener was not added.

FIG. 5 shows a graph of temperature changes of the heat storage material compositions of Examples 5 to 8 and Comparative Example 1 in the 26th heat cycle. As shown in FIG. 5, it is understood that the heat storage material compositions of Examples 5-8 have higher cooling rates and heating rates than the heat storage material composition of Comparative Example 1. In the 26th heat cycle, although the supercooling phenomenon of the heat storage material composition of Examples 5-8 is observed, it is understood that the 26th heat cycle has almost the same tendency as the 5th heat cycle. As a result, it was found that the addition of graphite powder to the heat storage material composition enabled rapid heat storage and heat release, and also enabled stable repeated use.

<Example 9>
43.9% by weight of solid-liquid phase change material (calcium chloride dihydrate), 10.0% by weight of melting point modifier (ammonium bromide), 20.8% by weight of water, mainly strontium chloride ( _SrCl2 ), 12.3% by weight of a nucleating material containing ), 10.0% by weight of graphite powder (average particle size 11.0 μm, flake graphite B), a hydrophilic thickener (PEG / PPG water-soluble copolymer, polymer The heat storage material composition of Example 9 was prepared by adjusting A) to 1.5% by weight.

<Example 10>
In the heat storage material composition of Example 9, the graphite powder was changed to graphite powder (average particle size 10.3 μm, flake graphite A), and the thickener was changed to another thickener (hypromellose, polymer B). used the heat storage material composition prepared in the same manner as in Example 9 as the heat storage material composition of Example 10.

<Example 11>
A heat storage material composition prepared in the same manner as in Example 9 except that graphite powder (average particle size: 11.2 μm, artificial graphite A) was used in the heat storage material composition of Example 9 was prepared. of the heat storage material composition.

<Example 12>
A heat storage material composition of Example 12 was prepared in the same manner as in Example 9, except that the graphite powder in the heat storage material composition of Example 9 was changed to graphite powder (average particle size: 10.3 μm, flake graphite A). of the heat storage material composition. 6 shows a component table of the heat storage material compositions of Examples 9 to 12 and Comparative Example 1. As shown in FIG.

<Evaluation method>
For the heat storage material compositions of Examples 9 to 12 and Comparative Example 1, the temperature change of each heat storage material composition was measured by repeating the heat cycle a predetermined number of times in the same manner as described above.

<Evaluation results>
FIG. 7 shows a graph of temperature changes of the heat storage material compositions of Examples 9 to 12 and Comparative Example 1 in the fifth heat cycle. As shown in FIG. 7, in the cooling of the heat cycle, the heat storage material compositions of Examples 9 to 12 have a faster cooling rate than the heat storage material composition of Comparative Example 1, and the supercooling phenomenon does not occur. I was able to reproduce what was suppressed. Furthermore, even when the type of graphite powder was changed and the type of thickening agent was changed, the same effects were obtained.

On the other hand, at the time of heating in the heat cycle, the heat storage material compositions of Examples 9 to 12 showed a faster heating rate and a faster rise in the graph compared to the heat storage material composition of Comparative Example 1. done.

FIG. 7 shows a graph of temperature changes of the heat storage material compositions of Examples 9 to 12 and Comparative Example 1 in the tenth heat cycle. As shown in FIG. 7, in the heat storage material compositions of Examples 9 to 12, compared with the heat storage material composition of Comparative Example 1, the cooling rate and the heating rate were increased. Also, it was confirmed that the 10th heat cycle exhibited substantially the same tendency as the 5th heat cycle.

<Example 13>
47.9% by weight of a solid-liquid phase change material (calcium chloride dihydrate), 10% by weight of a melting point regulator (ammonium bromide), 22.7% by weight of water, and mainly strontium chloride (SrCl ₂ ). Contains 13.4% by weight of nucleating material, 5.0% by weight of graphite powder (average particle size 10.3 μm, flake graphite A), and 1.0% by weight of hydrophilic thickener (xanthan gum, polymer C) A heat storage material composition of Example 13 was obtained by adjusting the heat storage material composition in the above manner.

<Example 14>
In the heat storage material composition of Example 13, the heat storage material composition of Example 14 was prepared in the same manner as in Example 13 except that the thickener was changed to another thickener (hydroxyethyl cellulose, polymer D). A heat storage material composition was obtained. 9 shows a component table of the heat storage material compositions of Examples 13 and 14 and Comparative Example 1. As shown in FIG.

<Evaluation method>
For the heat storage material compositions of Examples 13 and 14 and Comparative Example 1, the temperature change of each heat storage material composition was measured by repeating the heat cycle a predetermined number of times in the same manner as described above. The cooling time from about 60° C. to about 0° C. is 1 hour, and after standing at about 0° C. for 11 hours, the heating time from about 0° C. to about 60° C. is again 1 hour, and the temperature is about 60° C. for 11 hours. A heat cycle of cooling after standing for a period of time was repeated.

<Evaluation results>
FIG. 10 shows a graph of temperature changes of the heat storage material compositions of Examples 13 to 14 and Comparative Example 1 in the fifteenth heat cycle. As shown in FIG. 10, in the cooling of the heat cycle, the heat storage material composition of Examples 13 and 14 has a faster cooling rate than the heat storage material composition of Comparative Example 1, and the supercooling phenomenon does not occur. I was able to reproduce what was suppressed. Furthermore, even when the type of graphite powder was changed and the type of thickening agent was changed, the same effects were obtained.

On the other hand, at the time of heating in the heat cycle, the heat storage material compositions of Examples 13 and 14 showed a faster heating rate and a faster rise in the graph compared to the heat storage material composition of Comparative Example 1. done.

<Evaluation method>
The heat storage material compositions of Examples 13 and 14 were placed in a test tube, heat cycles were repeated, and the degree of sedimentation of the graphite powder was confirmed by the transparency of the test tube.

<Evaluation results>
FIG. 11 shows photographs of the test tube at the initial stage before the heat cycle, after the 55th heat cycle, and after the 120th heat cycle in Example 13, and at the beginning before the heat cycle and after the 30th heat cycle in Example 14. and a test tube photograph after the 80th heat cycle. As shown in FIG. 11, in the heat storage material composition of Examples 13 and 14, even if the heat cycle was repeated several tens of times or more, the graphite powder did not settle, and the light illuminated from the back side of the test tube did not cause the graphite powder to settle. It is understood that it is blocked by Presumably, the addition of the hydrophilic thickener remarkably suppresses the sedimentation of the graphite powder, which leads to an improvement in the cooling rate, suppression of the supercooling phenomenon, and an improvement in the heating rate.

<Comparative Example 2>
In the heat storage material composition of Comparative Example 1, the concentration of the melting point adjusting agent was fixed, the respective ratios of the solid-liquid phase change material, water, and nucleation material were the same, and instead of graphite powder, thermally conductive powder was used. A heat storage material composition of Comparative Example 2 was prepared in the same manner as in Comparative Example 1 except that 1.0% by weight of {triiron tetraoxide (Fe ₃ O ₄ )} was added.

<Comparative Example 3>
In the heat storage material composition of Comparative Example 1, the concentration of the melting point adjuster was fixed, the ratios of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the thermally conductive powder was 5.0. A heat storage material composition of Comparative Example 3 was prepared in the same manner as in Comparative Example 1 except that the weight percentage was changed.

<Comparative Example 4>
In the heat storage material composition of Comparative Example 1, the concentration of the melting point adjuster was fixed, the ratios of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the thermally conductive powder was 10.0. A heat storage material composition of Comparative Example 4 was prepared in the same manner as in Comparative Example 1 except that the weight percentage was changed.

<Comparative Example 5>
In the heat storage material composition of Comparative Example 1, the concentration of the melting point adjuster was fixed, the ratios of the solid-liquid phase change material, water, and nucleation material were the same, and the concentration of the thermally conductive powder was 20.0. A heat storage material composition of Comparative Example 5 was prepared in the same manner as in Comparative Example 1 except that the weight percentage was changed. Incidentally, FIG. 12 shows a component table of the heat storage material composition of Comparative Examples 1-5.

<Evaluation method>
For the heat storage material compositions of Comparative Examples 1-5, the ambient temperature of each heat storage material composition was lowered (cooled) from about 40°C to -4°C for a predetermined time, and then raised again from -4°C to 40°C ( The temperature change of each heat storage material composition was measured by repeating the heat cycle of the heating) operation a predetermined number of times.

<Evaluation results>
FIG. 13 shows a graph of temperature change of the heat storage material composition of Comparative Example 1-5 in the first heat cycle. As shown in FIG. 13, the heat storage material composition of Comparative Example 1-5 shows almost the same temperature curve during cooling and heating of the heat cycle, indicating that the thermally conductive powder has no effect at all. is understood.

FIG. 14 shows a graph of temperature change of the heat storage material composition of Comparative Example 1-5 in the fifth heat cycle. As shown in FIG. 14, even in the fifth heat cycle, the temperature curve is almost the same as in the first heat cycle, and it is understood that the thermally conductive powder has no action or effect.

As a result, it was found that by adding graphite powder and a hydrophilic thickener to the heat storage material composition, it is possible to quickly store and dissipate heat, and to use it stably and repeatedly.

In the examples and comparative examples of the present invention, evaluation was performed by adding ammonium bromide as a melting point adjuster so that the freezing point (melting point) of the heat storage material composition was 18°C. Even if it does not add, it has the same effect. In the present invention, it is not necessary to limit the freezing point of the heat storage material composition to 18° C., and the same effect can be obtained even if the freezing point is another freezing point.

As described above, the heat storage material composition according to the present invention is useful as a heat storage material in various fields, enables rapid heat storage and heat dissipation, and is a heat storage material composition that can be stably and repeatedly used. It is valid.

Claims (2)

a solid-liquid phase change material that undergoes a phase change between a solid and a liquid within a predetermined temperature range;
water and,
a nucleating material containing strontium chloride as a main component;
graphite powder ;
a hydrophilic thickener;
contains _
The concentration of the graphite powder is 1.0% by weight to 10.0% by weight with respect to the total heat storage material composition,
The graphite powder has an average particle size of 5 μm to 20 μm,
The concentration of the thickening agent is 0.1% by weight to 5.0% by weight with respect to the total heat storage material composition.
A heat storage material composition. The thickening agent contains either a PEG/PPG water-soluble copolymer, hypromellose, xanthan gum, or hydroxyethyl cellulose.
The heat storage material composition according to claim 1 .

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