JP2003321674A - Heat reservoir - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat reservoir having improved thermal storage efficiency by making its freezing point easily controllable or a heat reservoir easy solidifiable in heat reserving and having a low heat releasing temperature, increased heat reserving capacity and, thereby, improved heat reserving performance by nearing its solidifying temperature to its melting temperature. <P>SOLUTION: This heat reservoir consists essentially of a water dispersion comprising an oily material having heat reserving property depending on phase change and a surfactant, wherein the oily material (1) comprises ≥3 components and has ≥0.3 but ≤0.5 variance of each component mass fraction or (2) comprises ≥2 components and has ≥0.9 but <1.0 variance of each component mass fraction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat storage body.
More specifically, the present invention relates to a heat storage body that essentially includes an aqueous dispersion containing an oily substance having heat storage properties due to a phase change as an essential component.

[0002]

2. Description of the Related Art A heat storage facility is installed in a corner of a building for the purpose of labor saving and efficiency improvement of air conditioning and heating energy for large buildings such as office buildings and factories, household use, etc., and environmental protection. For air conditioning, a system for temporarily storing heat by installing a plurality of heat storage devices each having a size of 4, 5 meters square has attracted attention.

In such a heat storage device, a heat storage material composed of a heat storage substance is filled in the device, a medium such as circulating water that transfers heat is passed through the device, and the phase of the heat storage substance is changed by energy such as electric power. By doing so, the latent heat of radiating heat at the phase change from solid to liquid and absorbing heat at the phase change from liquid to solid is utilized. For example, the heat storage body is cooled and solidified by electric power at night, and the endothermic effect at the time of melting is used for cooling in the daytime.

The heat storage substance constituting the heat storage body is preferably a mixture containing paraffin and the like, which is cooled and solidified at about 5 to 14 ° C. and is composed of a heat storage substance having a large heat of fusion. There is. Regarding such a heat storage body, in JP-A-2000-336350, 1 ° C. to 30 ° C. higher than the phase change temperature of saturated hydrocarbon with phase change, water, a surfactant, and saturated hydrocarbon as a nucleating agent. A heat storage material composed of an emulsion using a saturated hydrocarbon having a high phase change temperature of ℃ is disclosed. However, in such a heat storage material, it is easy to adjust the freezing point, that is, it is easy to solidify according to the heat storage device to improve heat storage efficiency, and since the solidification temperature and the melting temperature are close to each other, it is easy to solidify during heat storage. There was room for improvement in that it was possible to lower the temperature at the time of heat dissipation and to improve the heat storage performance by increasing the amount of latent heat.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and a heat storage body in which the freezing point is easily adjusted and the heat storage efficiency is improved, or because the freezing temperature and the melting temperature are close to each other, It is an object of the present invention to provide a heat storage body that is easily solidified during heat storage and can lower the temperature during heat radiation, and that has an increased latent heat amount and improved heat storage performance.

[0006]

Means for Solving the Problems As a result of various studies on the heat storage body, the present inventors have found that a heat storage body which essentially includes an aqueous dispersion containing an oily substance having a heat storage property due to a phase change and a surfactant is required. Focusing on preventing supercooling due to the effect of the surfactant, making it easier to solidify and improving heat storage efficiency,
When the oily substance is composed of three or more components and the dispersion of the mass fraction of each component is 0.3 or more and 0.5 or less, the freezing point is easily adjusted and the heat storage efficiency is further improved. I found out that would be the case. Further, when the oily substance is composed of two or more components and the mass fraction dispersion of each component is 0.9 or more and less than 1.0, the oily component can be obtained from petroleum or the like at a relatively low cost, and Since the solidification temperature and the melting temperature are close to each other, it is possible to easily solidify during heat storage and to lower the temperature during heat dissipation, and to find that the latent heat amount is increased to improve heat storage performance, and to solve the above problems brilliantly. The present invention has been made, and has reached the present invention.

That is, the present invention relates to a heat storage body which essentially comprises an aqueous dispersion containing an oily substance having a heat storage property by a phase change and a surfactant, wherein the oily substance is composed of three or more components. It is a heat storage material in which the dispersion of the mass fraction of each component is 0.3 or more and 0.5 or less.

The present invention is also a heat storage body which essentially comprises an aqueous dispersion containing an oily substance having a heat storage property by a phase change and a surfactant, wherein the oily substance is composed of two or more components. And the variance of the mass fraction of each component is 0.
It is also a heat storage material of 9 or more and less than 1.0. The present invention is described in detail below.

The heat storage material of the present invention essentially comprises an aqueous dispersion containing an oily substance having a heat storage property due to a phase change and a surfactant, and can store heat energy such as sensible heat storage, latent heat storage, chemical reaction heat storage and the like. It can be stored and released. Having a heat storage property by a phase change means having a latent heat storage that utilizes latent heat at the time of a phase change or a phase transition as a heat storage property, and such an oily substance has a high heat storage density and near a constant temperature. It is capable of storing and radiating heat.

The oily substance constituting the heat storage body of the present invention is
(1) It consists of three or more components, and the dispersion of the mass fraction of each component is 0.3 or more and 0.5 or less, or (2) it is composed of two or more components, and the mass of each component The dispersion of the fraction is 0.9 or more and less than 1.0. In the case of (1), the dispersion of the mass fraction of each component is preferably 0.35.
Or more and 0.45 or less, and in the case of (2), it is preferably 0.920 or more, and 0.9
It is 98 or less.

The dispersion (V) of the mass fraction of each of the above components is a value obtained by the following formula.

[0012]

[Formula 1]

In the formula, n represents the number of components constituting the oily substance. x represents the mass fraction of each component when the total mass of the oily substance is 1. When the dispersion (V) obtained by the above formula is 0, it means that all components constituting the oily substance are in the same amount, and when the dispersion (V) is 1.0, the oily substance is constituted. It means that the components are single components (one component constitutes 100% of the oily substance).
In addition, in the function (VAR) for determining the variance for the population by regarding the argument as a sample of the population, the variance is calculated by the following formula.

[0014]

[Formula 2]

In the formula, n and x are the same as above. In the present invention, when there is no dispersion regardless of the number of components constituting the oily substance (when one component constitutes 100% of the oily substance), 1.0, when the maximum dispersion (all components constituting the oily substance (When the components of is the same amount) is set to 0,
The calculation formula of the VAR function is multiplied by the number of components n so as to be 0 to 1.0. Therefore, the formula for calculating the variance (V) of the mass fraction of each component is the formula obtained by multiplying the formula for the VAR function by the number of components n.

As the component constituting the above oily substance, hydrocarbon compounds such as paraffin and α-olefin; higher fatty acids; higher fatty acid esters; higher alcohols and the like are preferable, and specifically, C ₁₅ paraffin, C
Suitable are medium-grade paraffins such as ₁₄ paraffin and C ₁₆ paraffin that are liquid at room temperature; higher paraffins that are solid at room temperature such as C ₁₇ paraffin and C ₁₈ paraffin; and higher alcohols such as 1-decanol. In the form (1), three or more of these components are used, and in the form (2), two or more of these components are used in combination. Among these, in the case of the heat storage body for building air conditioning, those that are liquids at room temperature (25 ° C.) and normal pressure (about 101.3 kPa) are preferable because they are easy to handle.
It is preferably used as a component constituting an oily substance.
Further, paraffin is preferable because it can be easily obtained and can easily and stably produce a heat storage material that can be used in a wide temperature range. It is preferable to include. In the present invention, one compound constitutes one component. For example, when paraffins having the same carbon number and isomers such as straight chain paraffin and branched paraffin are included, each of them is regarded as one component. To do.

As an oily substance in the form (1) above
Is cheap, easy to obtain, and easy to adjust phase change temperature
Therefore, there are three or more components, and
Homologs of elementary compounds are preferred. For example, for cold heat applications
If so, C₁₄Paraffin, C ₁₅Paraffin and C₁₆Pa
Mixtures of paraffins with carbon numbers greater than or equal to raffins; C₁₄Para
Fin, C₁₆Paraffin and C₁₈Paraffin mixture etc.
Is preferred. The mass fraction of these is C₁₄
Paraffin, C₁₅Paraffin and C₁₆More than paraffin
In a mixture of carbon number paraffins, C₁₄Paraffin: C
₁₅Paraffin: C ₁₆Paraffin with more carbons than paraffin
Is preferably 0.2 to 30:50 to 80: 2 to 20.
R, C₁₄Paraffin, C₁₆Paraffin and C₁₈Parafi
In a mixture of₁₄Paraffin: C₁₆Paraffin: C
₁₈Paraffin = 0.2-40: 50-60: 2-10
Oily substances that are suitable and composed of such ingredients
Is one of the preferred embodiments of the present invention.

The oily substance in the form (2) is preferably a substance containing at least one hydrocarbon compound selected from the group consisting of 14, 15, 17 and 19 as the main component. More preferably, the main component is a hydrocarbon compound having 14 and / or 15 carbon atoms. In addition, the hydrocarbon compound is preferably paraffin. The term "main component" means a component that constitutes 50% by mass or more when all components constituting the oily substance are 100% by mass.
It may be composed of one component or may be composed of two or more components. When the main component is composed of two or more components, the total of each component constituting the main component may be 50% by mass or more.

The amount of the oily substance used may be appropriately set according to the type of the oily substance, the usage form of the heat storage body, and the required heat storage efficiency. It is preferable that the amount is 100% by mass or less. If it is less than 10% by mass, the heat storage efficiency and the heat storage performance may decrease. More preferably, it is 20% by mass or more and 75% by mass or less.

As the surfactant used in the heat storage material of the present invention, sorbitan ester compounds such as polyoxyalkylene sorbitan alkyl ester and sorbitan alkyl ester; sucrose fatty acid ester; sodium alkyl sulfonate; sodium alkylbenzene sulfonate; polyoxy Preference is given to ethylene alkyl ethers; polyoxyethylene alkylphenol ethers; polyoxyethylene alkyl esters; polyglycerin alkyl esters; fatty acid soaps. These may be used alone or in combination of two or more. Among these,
It is preferably at least one selected from the group consisting of polyoxyalkylene sorbitan alkyl ester, sorbitan alkyl ester, and sucrose fatty acid ester. More preferably, it is a polyoxyalkylene sorbitan alkyl ester and / or sorbitan alkyl ester or sucrose fatty acid ester. More preferred are polyoxyalkylene sorbitan alkyl ester and sucrose fatty acid ester.

The amount of the above-mentioned surfactant to be used is appropriately set depending on the kind of the oily substance having a heat storage property due to the phase change and the like.
It is preferably 0.1% by mass or more, and preferably 30% by mass or less. More preferably, 1.
It is 0% by mass or more and 20% by mass or less.

The heat storage material of the present invention may further contain additives having the functions described below. These may be used alone or in combination of two or more. (1) For improving heat transfer: Metal powder such as iron and copper: metal fiber; metal oxide; carbon; carbon fiber and the like. (2) For adjusting specific gravity: sand; clay; stone; metal powder such as lead and iron.

(3) For imparting flame retardancy: water; water gel; metal powder; inorganic compounds such as calcium carbonate; bromine-based, chlorine-based,
Flame retardants such as phosphorus. In addition, flame retardance means reduction of flammability,
This includes prevention of fire spread, extinction of flash point due to steam, and reduction of combustion heat. (4) To prevent supercooling: Metal powder, polymer paraffin (wax), etc. (5) For freezing point adjustment: waxes and the like. (6) For preventing oxidation and deterioration over time: Phenolic type,
Thio-type and phosphorus-type antioxidants, etc. (7) Others: colorants, pigments, antistatic agents, antibacterial agents, etc.

The amount of the above-mentioned additive used is preferably 10 to 40% by mass based on the oily substance when calcium carbonate is used to reduce flammability.

An inclusion compound for adjusting the latent heat property may be added to the oily substance. Examples of the inclusion compound include C ₄ H ₈ · O · 17H ₂ O and (CH ₃ ) ₃ N · 10.2.
5H ₂ O, (C ₄ H ₉ ) ₄ NCHO ₂ · 32H ₂ O, (C
₄ H ₉ ) ₄ NCH ₃ CO ₂ .32 H ₂ O is preferred. These may be used alone or in combination of two or more.

As a method for producing the aqueous dispersion of the present invention, a method of making an oily substance into an aqueous dispersion may be applied. For example, heat storage in an aqueous solution in which a surfactant is dissolved in an aqueous medium by phase change. A method of adding an oily substance having properties and emulsifying by stirring or the like is suitable. A machine used for emulsification in producing the heat storage body is not limited, and a general machine can be used. For example, a propeller stirrer,
High-speed rotary stirrer, homomixer, high-pressure homogenizer,
There are colloid mills, roll mills, roller mills, sand mills, ball mills, in-line continuous emulsifiers, ultrasonic emulsifiers, vacuum kneaders, vacuum emulsifiers, and release emulsifiers. The aqueous medium is water or a mixture of water and a solvent that dissolves in water, and water; a mixed solvent of water and methanol, ethanol, isopropyl alcohol, acetone, acetonitrile, or the like is preferable, but among these, water is preferable. It is preferred to use only one. The amount of the aqueous medium used is preferably 5.0% by mass or more and 900% by mass or less with respect to 100% by mass of the oily substance.

The heat storage material of the present invention essentially comprises an aqueous dispersion containing an oily substance having a heat storage property due to a phase change and a surfactant. The usage form is an emulsion-like water dispersion. It is preferably in the form of a body, and may be used as a heat storage body filled in a packaging material. It is preferable that such a heat storage body is stored and used in a heat storage tank forming a heat storage device.

The heat storage body of the present invention is used in various heat storage devices in the form of an emulsion or in a packaged state. As such a heat storage device, (1) the heat storage medium serves as a heat carrier medium. Examples thereof include those that perform heat exchange, and (2) those that include a heat storage tank in which a heat storage body is stored and that can perform heat exchange of a heat medium.

As the heat storage device of the above (1), a heat storage device using a heat storage body in which water is dispersed is preferable, and the heat storage body circulates between the heat storage tank and the heat exchanger, or outside the heat storage tank. Examples of the heat storage device include a heat storage device that exchanges heat by circulating heat, and a heat carrier medium system is formed by such a heat storage device. As described above, the heat carrier medium in which the heat storage medium of the present invention is dispersed in water, the heat storage device using the heat carrier medium in which the heat storage medium of the present invention is dispersed in water, and the heat carrier medium in which the heat storage medium of the present invention is dispersed in water are used. The conventional heat carrier medium system is also one of the preferred embodiments of the heat storage body of the present invention,
It is preferably used for a heat carrier medium system for district heating and cooling systems and building air conditioning systems.

The heat storage device of the above (2) is provided with a heat storage tank in which a heat storage body is stored, and is capable of exchanging heat with the heat medium. However, the one in which the heat storage body is stored is preferable. Such a heat storage device is one of the preferred embodiments of the present invention. As the heat storage device configured to store the heat storage body, it is preferable to provide a heat storage tank with heat exchange means so that heat energy can be transferred to and from a heat medium circulating outside the heat storage device. , Those equipped with a heat exchanger for exchanging heat of the heat medium in the heat storage tank in which the heat storage body stores, or only the heat medium passes through the heat storage tank while the emulsion-like water dispersion is stored in the heat storage tank The thing etc. which were done are mentioned.

In the heat storage body of the present invention, the freezing point can be easily adjusted to improve the heat storage efficiency, or since the solidification temperature and the melting temperature are close to each other, the heat storage body easily solidifies during heat storage and can lower the temperature during heat radiation. In addition, because the latent heat amount is increased and the heat storage performance is improved, heat storage for the purpose of labor saving and efficiency improvement of cooling and heating energy for large buildings such as office buildings and factories, household use, and environmental protection It is an excellent material for the device.

[0032]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" is
It means "parts by weight".

Example 1 In a glass beaker having an internal capacity of 500 ml, polyoxyethylene sorbitan alkyl ester (surfactant, manufactured by Kao Corporation: trade name Rheodor Super TW-L120) 2.4
Part was added to 72.8 parts of water (aqueous solvent and aqueous medium) and stirred to obtain an aqueous solution. Then, paraffin (1) distilled from kerosene as an oily substance (19.4 mass% tetradecane, 73.5 mass% pentadecane,
Hexadecane 6.9% by mass, heptadecane 0.2% by mass, number of components 4, dispersion 0.44) 80 parts of sucrose fatty acid ester (surfactant, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .: trade name Sugar Wax A-10E). Dissolve 4.8 parts, add to the above aqueous solution, stirrer (TK Homomixer manufactured by Tokushu Kika Co., Ltd.)
Was emulsified by stirring at 12000 rpm for 3 minutes. Further, 240 parts of water was added to the above emulsion to obtain an aqueous dispersion having an oily substance concentration of 20% by mass. Thereby, the heat storage body (water dispersion) 1 according to the present invention was obtained. The average particle diameter of the heat storage body 1 was 3 μm.

With respect to the obtained heat storage body 1, a differential scanning calorimetry (DSC (differentialia) was conducted under predetermined conditions.
(1 scanning calorimetry)) to determine the solidification temperature and the melting temperature. For differential scanning calorimetry, differential scanning calorific value DSC-3100S manufactured by Mac Science Co. was used. As the measurement conditions,
After cooling from 25 ° C to -20 ° C at a rate of 2 ° C / min,
The temperature was raised from -20 ° C to 25 ° C at a rate of 2 ° C / min. As a result, the solidification temperature (solidification start temperature) was 7.3 ° C, and the melting temperature (melting peak temperature) was 8.3 ° C.

Comparative Example 1 In Example 1, instead of paraffin (1), a paraffin mixture (tetradecane (manufactured by Wako Pure Chemical Industries, Ltd.) 12.
5% by mass, pentadecane (manufactured by Wako Pure Chemical Industries, Ltd.) 87.5
Mass%: number of components 2, dispersion 0.56) A comparative heat storage body 1 was obtained in the same manner as in Example 1 except that 80 parts were used. The average particle size of the comparative heat storage body 1 was 3 μm.

Regarding the obtained comparative heat storage body 1, Example 1
The solidification temperature and melting temperature were determined in the same manner as in. As a result, the solidification temperature was 7.6 ° C and the melting temperature was 8.5 ° C.

From Example 1 and Comparative Example 1, the paraffin (1) that can be distilled from kerosene in Example 1 is the same as Comparative Example 1
It was found that the freezing point was lower than that of the reagent mixture in 1) and any freezing point was possible.

Example 2 In a glass beaker having an internal capacity of 500 ml, polyoxyethylene sorbitan alkyl ester (surfactant, manufactured by Kao Corporation, trade name: Leodol Super TW-L120) 6.9.
Parts, sorbitan alkyl ester (surfactant, manufactured by Kao Corporation, trade name: Leodol SP-S30) 1.6 parts, and sodium dodecyl sulfate 0.1 part are added to water (aqueous solvent and aqueous medium) 71.4 parts. Then, the solution was heated to 70 ° C. and stirred for 30 minutes to obtain an aqueous solution. Next, as an oily substance, paraffin (2) (99.9% by mass of pentadecane, 0.1% by mass of hexadecane: the number of components is 2, the dispersion is 0.9).
96) 80 parts was added to the above aqueous solution, and 12000 rpm, 3 with a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.)
The mixture was stirred for a minute and emulsified. Further, 240 parts of water was added to the above emulsion to obtain an aqueous dispersion having an oily substance concentration of 20% by mass.
Thereby, the heat storage body (water dispersion) 2 according to the present invention was obtained. The average particle diameter of the heat storage body 2 was 2 μm.

With respect to the obtained heat storage body 2, a differential scanning calorimetry (DSC (differentialia) was conducted under predetermined conditions.
(1 scanning calorimetry)) to determine the solidification temperature and the melting temperature. As a result, the solidification temperature (solidification start temperature) was 9.3 ° C, the melting temperature (melting peak temperature) was 10.5 ° C, and the difference between the melting point temperature and the solidification temperature was 1.2 ° C.

Comparative Example 2 In Example 2, 80 parts of paraffin (2 ') (10.0% by mass of tetradecane, 90.0% by mass of pentadecane: the number of components 2, dispersion 0.64) was used instead of paraffin (2). A comparative heat storage body 2 was obtained in the same manner as in Example 2 except that it was used. The average particle diameter of the comparative heat storage body 2 was 2 μm.

Regarding the obtained comparative heat storage body 2, Example 2 was used.
The solidification temperature and melting temperature were determined in the same manner as in. As a result, the solidification temperature was 7.2 ° C., the melting temperature was 9.0 ° C., and the difference between the melting point temperature and the solidification temperature was 1.8 ° C., which was large as compared with Example 2.

From Example 2 and Comparative Example 2, it was found that the difference between the melting point temperature and the freezing point temperature was reduced in the present invention.

[0043]

EFFECTS OF THE INVENTION The heat storage material of the present invention has the above-mentioned structure, and the freezing point is easily adjusted to improve the heat storage efficiency, or the freezing temperature and the melting temperature are close to each other, so that the freezing point is likely to be solidified during heat storage. It is possible to lower the temperature, and since the latent heat amount is increased and the heat storage performance is improved, labor saving and efficiency improvement of cooling and heating energy for large buildings such as office buildings and factories and households, It is an excellent material for a heat storage device for the purpose of environmental protection.

Claims (4)

[Claims] 1. A heat storage body essentially comprising an aqueous dispersion containing an oily substance having a heat storage property due to a phase change and a surfactant, wherein the oily substance is composed of three or more components. A heat storage material, wherein the dispersion of the mass fraction of the components is 0.3 or more and 0.5 or less. 2. The heat storage material according to claim 1, wherein the surfactant is at least one selected from the group consisting of polyoxyalkylene sorbitan alkyl ester, sorbitan alkyl ester and sucrose fatty acid ester. . 3. A heat storage body essentially comprising an aqueous dispersion containing an oily substance having a heat storage property due to a phase change and a surfactant, wherein the oily substance is composed of two or more components, Dispersion of the mass fraction of a component is 0.9 or more and less than 1.0, The heat storage body characterized by the above-mentioned. 4. The oily substance has a carbon number of 14, 15,
The heat storage body according to claim 3, wherein the main component is at least one hydrocarbon compound selected from the group consisting of 17 and 19.