JP2004211056A - Heat storage material and heat storage system using heat storage material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat storage material which has improved flowability due to the enhanced dispersibility of an oily substance, improved heat conduction performance, and excellent emulsion stability, and to provide a heat storage apparatus or heat storage system which can suitably be used for the saving and efficiency improvement of air-conditioning energy, the protection of environments, and the like. <P>SOLUTION: This heat storage material used for the heat storage apparatus or heat storage system is characterized by comprising a dispersion prepared by dispersing a mixture consisting essentially of an oily substance having a heat storage property by the change of phase, an aqueous medium, a surfactant and a polymer dispersant in an oil-in-water drop type. The heat storage material is characterized in that the change of the volume-average particle diameter of an oil-in-water drop type dispersion consisting essentially of the oily substance having the heat storage property by the change of phase and the aqueous medium and used for the heat storage material is within ±50% of the volume-average particle diameter of the un-sheared oil-in-water drop type dispersion, when the oil-in-water drop type dispersion is stirred and sheared in a state that the oily substance in the oil-in-water drop type dispersion is coagulated by the change of the phase. The heat storage materials are used. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

The present invention relates to a heat storage device and a heat storage device or a heat storage system using the heat storage material. The heat storage body includes a water dispersion containing an oily substance having heat storage property by phase change as an essential component, and is used for a heat storage system in a large-scale building such as an office building or a factory, or in a cooling / heating device such as a home. Is what you can do.

As an oil-based heat storage substance using latent heat, aliphatic hydrocarbons, fatty acids, and fatty acid esters are known. Such oil-based heat storage materials have the property of radiating heat during the phase change from solid to liquid and absorbing heat during the phase change from liquid to solid. This is used for heat storage systems to save energy and save energy for cooling and heating energy. Attention has been focused on technologies that can be used for purposes such as environmental protection and environmental protection. For example, as a heat storage device using a heat storage material containing an oil-based heat storage material, the heat storage material is cooled and solidified by circulating the heat storage material between a heat storage tank and a refrigerator, and the heat absorbing effect at the time of melting is utilized for cooling. What is being used is being used.

In order to effectively utilize such an oil-based heat storage material, a method has been proposed in which a surfactant is used to prepare and use an oil-in-water emulsion of the oil-based heat storage material and water. For example, a heat storage material composed of an emulsion composed of paraffin, water and a surfactant is disclosed (for example, see Patent Document 1). Further, a heat storage material comprising an emulsion using a saturated hydrocarbon having a phase change, water, a surfactant, and a specific nucleating agent is disclosed (for example, see Patent Document 2). In these heat storage materials, the oily substance is dispersed using a surfactant.For example, the heat storage material in the heat storage tank is separated on the tank, and the dispersibility and fluidity of the emulsion are reduced. Become. Therefore, there is room for improvement for improving the stability of the emulsion.

Further, the heat storage material dispersion has a viscosity at 25 ° C. within a specific range, and discloses a dispersion of fine particles of a heat storage material used for temperature-stratified heat storage (for example, see Patent Document 3). In this technique, fine particles of the heat storage material are dispersed using a dispersant, but in the examples, only a water-soluble polymer is used as a dispersant, and there is room for contriving to improve the stability of the emulsion. Was.

Further, the oily substance relates to composite particles for a heat transfer medium held inside a specific lipophilic polymer particle, and a monomer component containing an oily substance and a crosslinkable monomer in an aqueous solution containing a surfactant. It has been disclosed that a heat transfer medium was obtained by adding a mixed solution of the above and polymerizing (see, for example, Patent Document 4). Such a heat transfer medium is suitable as a heat transfer medium used in an air conditioning system or the like because it can sufficiently prevent oozing of an oily substance from a polymer during use. In addition, it is described that in the production of such a heat transfer medium, suspension polymerization may be performed in the presence of a protective colloid agent. However, by examining the components of the heat transfer medium obtained by such a manufacturing method, and by improving the dispersibility and fluidity of the oily substance and the stability of the emulsion, the heat storage that repeats solidification / melting in the heat storage / radiation operation is performed. There is room for devising a heat storage body having excellent stability as a dispersion even in cycles.

JP-A-57-40582 (page 1-2) JP-A-2000-336350 (pages 2-4) JP-A-2002-53850 (pages 2-4) WO 99/15602 pamphlet (2, 14, 21-24 pages)

The present invention has been made in view of the above-mentioned circumstances, and provides a heat storage body in which the dispersibility of an oily substance is enhanced, the fluidity is improved, the heat transfer performance is improved, and the stability of the emulsion is excellent. The purpose is. Another object of the present invention is to provide a heat storage device or a heat storage system that can be suitably used for purposes such as labor saving and efficiency of cooling and heating energy, environmental protection, and the like.

The present inventors have conducted various studies on a heat storage body using an oily substance having heat storage properties due to a phase change. As a result, it has been found that an oily substance dispersed in an aqueous medium has high safety and is widely used in various heat storage systems. Focusing on the fact that an oily substance having a heat storage property due to a phase change is dispersed in an aqueous medium with a surfactant to form an emulsion, it has been found that it is suitable as a heat storage body. Paying attention to the fact that the dispersion state of the oily substance in the aqueous medium is related to the fluidity of the dispersion and the stability as a dispersion, including an oily substance having a heat storage property due to a phase change, an aqueous medium, and a surfactant. By using a polymer dispersant as a protective colloid in the dispersion and dispersing it in an oil-in-water type, the dispersibility of the oily substance is increased, the fluidity is improved, and the heat transfer performance is improved. And found that the stability of the emulsion can be improved. As a result, it is possible to obtain a heat storage body having excellent stability as a dispersion even in a heat storage cycle in which solidification / melting is repeated in heat storage / radiation operation without causing the emulsion to disintegrate and an oily substance to be separated. From the above, they came up with the idea that the above problems can be solved successfully.
In addition, the present inventors studied the performance improvement of the heat storage body, and when the oily substance in the oil-in-water type dispersion was solidified by phase change and shearing was applied by stirring, the oil-in-water type dispersion was confirmed. Dispersion and fluidity of oil-based substances, stability of emulsion by making the heat storage body the variation of the volume average particle diameter of the body within ± 50% compared to the volume average particle diameter before applying shear Have been found to be excellent in the stability of the dispersion in the heat storage / radiation operation, and have reached the present invention.

That is, the present invention is a heat storage body comprising a dispersion obtained by dispersing a mixture essentially including an oily substance having a heat storage property by a phase change, an aqueous medium, a surfactant, and a polymer dispersant in an oil-in-water type. .
Hereinafter, the present invention will be described in detail.

The heat storage element of the present invention comprises a dispersion obtained by dispersing an oily substance having heat storage property by a phase change in an aqueous medium by essentially using a polymer dispersant together with a surfactant. As described above, by using a surfactant and a polymer dispersant in combination, it is possible to sufficiently improve the stability of the emulsion by a synergistic effect of these.
In the present invention, each of these production raw materials constituting the heat storage material may be used alone or in combination of two or more.

The polymer dispersant in the present invention is not particularly limited as long as it is a polymer substance which is easily wetted by water or easily dissolved in water. For example, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyvinyl methyl ether, polyethylene oxide, polypropylene oxide, (meth) acrylate copolymer, (meth) acrylate (meth) acrylate copolymer, methylcellulose, methylhydroxyl Propylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, soluble starch, dextrin, gum arabic, chitosan, agar, gelatin, soybean casein, polyacrylic acid, sodium polyacrylate, acrylic acid acrylate copolymer, acrylic Sodium maleate copolymer, polymaleic acid, polyvinyl sulfonic acid, polystyrene sulfonic acid sodium Beam, sodium carboxymethyl cellulose, polyethyleneimine, polydiallylamine, polyallylamine, poly N- vinylformamide, polyvinylamine, polyamidine the like. In a polymer dispersant which is easily dissolved in water, it is preferable that 80% by mass or more is dissolved when dissolved in water at 25 ° C.
Among these, as the nonionic polymer dispersant, those having a weight average molecular weight of 5,000 to 300,000 are preferable, and those having a weight average molecular weight of 50,000 to 200,000 are more preferable. As the polymer dispersant, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxypropyl methylcellulose and the like are preferable. As the ionic polymer dispersant, those having a weight average molecular weight of 5,000 to 3,000,000 are preferable, preferably 50,000 to 3,000,000, and more preferably 100,000 to 2,000,000. As the ionic polymer dispersant having the above, sodium polyacrylate and the like are preferable.

The amount of the polymer dispersant used is preferably 0.001% by mass or more, and more preferably 5% by mass or less, based on 100% by mass of the oily substance having heat storage property due to phase change. More preferably, it is 0.01% by mass or more and 3% by mass or less.

The oily substance in the present invention has heat storage properties due to a phase change. That is, it has a latent heat storage utilizing the latent heat at the time of a phase change or a phase transition as a heat storage property, has a high heat storage density, and is capable of storing and releasing heat near a certain temperature. This makes it possible to store and release thermal energy such as sensible heat storage, latent heat storage, and chemical reaction storage.

Compounds such as hydrocarbon compounds such as paraffins and α-olefins; higher fatty acids; higher fatty acid esters; and higher alcohols are suitable as components constituting the oily substance. Specifically, C ₁₄ paraffin, Intermediate paraffins that are liquid at room temperature, such as C ₁₅ paraffin and C ₁₆ paraffin; C ₁₇ paraffin, C ₁₈ paraffin, C ₁₉ paraffin, C ₂₀ paraffin, C ₂₁ paraffin, C ₂₂ paraffin, C ₂₃ paraffin, C ₂₄ paraffin, C Higher paraffins such as ₂₅ paraffins which are solid at around normal temperature; higher alcohols such as 1-decanol are preferred. Among these, the heat storage element for building air conditioning is a liquid that is liquid at normal temperature (25 ° C.) and normal pressure (approximately 101.3 kPa) because of its ease of handling. It is preferable to use it as a component constituting the substance. In addition, paraffin is preferred because it is easily available and can easily and stably produce a heat storage material that can be used in a wide temperature range. It is preferable to include

As the oily substance, a single component may be used.However, the melting point can be adjusted to the heat storage temperature to be used by arbitrarily adjusting the type and the mixing ratio of the oily substance having heat storage property by phase change. it can. When used for cooling purposes, an oily substance having heat storage properties by a phase change having a melting point of about 5 to 20 ° C. may be selected. When used for heating purposes, an oily substance having a heat storage property by a phase change having a melting point of about 40 to 60 ° C. may be selected.

The amount of the oily substance to be used may be appropriately set according to the type of the oily substance having heat storage due to the phase change, the use form of the heat storage, and the required heat storage efficiency. % Or more, and preferably less than 100% by mass. If it is less than 10% by mass, the heat storage efficiency and the heat storage performance may be reduced. More preferably, the content is 20% by mass or more and 75% by mass or less.

In the heat accumulator of the present invention, the aqueous medium contains water as an essential component, but a mixture of water and a solvent soluble in water can be used.For example, water and methanol, ethanol, isopropyl alcohol, acetone , Acetonitrile, a mixed solvent with ethylene glycol, diethylene glycol and the like are preferable. The proportion of water in the aqueous medium is preferably at least 50% by mass, more preferably at least 80% by mass. More preferably, only water is used.
The amount of the aqueous medium to be used is preferably 5.0% by mass or more, and more preferably 900% by mass or less with respect to 100% by mass of the oily substance having heat storage property due to phase change.

As the surfactant in the present invention, it is preferable to use a nonionic surfactant as an essential component, and as the nonionic surfactant, polyoxyalkylene sorbitan alkyl esters such as polyoxyethylene sorbitan stearate, and sorbitan Sorbitan ester compounds such as alkyl esters; sucrose fatty acid esters; polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether and polyoxyethylene benzyl ether; polyoxyethylene alkyl phenol ether; polyoxyethylene alkyl ester; polyglycerin alkyl ester Fatty acid esters; fatty acid soaps; alkylamine ethylene oxide adducts; and sterols such as cholesterol. These may be used alone or in combination of two or more. Among them, polyoxyethylene (ethylene oxide added mole number 20 or more) alkyl (total carbon number 15 or more) ether and / or polyoxyethylene (ethylene oxide added mole number 20 or more) sorbitan alkyl (total carbon number 15 or more) ester Is an essential component. In such an essential component, the added mole number of ethylene oxide is 20 or more, preferably 100 or less, more preferably 50 or less. Further, the total carbon number is 15 or more, preferably 40 or less, more preferably 30 or less.
Among these, polyoxyethylene stearyl ether, polyoxyethylene benzyl ether, and polyoxyethylene sorbitan stearate having an ethylene oxide addition mole number of 20 or more are more preferable.

As the surfactant, an amphoteric surfactant, an anionic surfactant, a nonionic-anionic surfactant, and a cationic surfactant may be appropriately used. Examples of such surfactants include alkyl sulfate salts such as sodium alkyl sulfonate; alkyl benzene sulfonic acids and salts thereof such as sodium alkyl benzene sulfonate; alkyl (phenyl) ether sulfate salts such as sodium polyoxyethylene lauryl ether sulfate; tetradecene Α-olefin sulfonates such as sodium sulfonate; sulfosuccinates; ether sulfonates; ether carboxylic acids and salts thereof; betaines such as amidopropyl betaine laurate; and quaternary ammoniums such as dialkylammonium chloride.

The amount of the surfactant to be used is preferably 0.1% by mass or more, and more preferably 30% by mass or less based on 100% by mass of the oily substance having heat storage property due to phase change. More preferably, the content is 1.0% by mass or more and 20% by mass or less.

The heat storage body of the present invention may further contain an additive having the functions described below.
(1) For improving heat transfer: metal powder such as iron and copper: metal fiber; metal oxide; carbon;
(2) Specific gravity adjustment: 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, and phosphorus-based flame retardants. The flame retardancy includes a reduction in flammability, prevention of spread of fire, extinction of a flash point by steam, an effect of reducing the amount of combustion heat, and the like.
(4) For supercooling prevention: metal powder, polymer paraffin (wax), etc.
(5) For solidification point adjustment: waxes and the like.
(6) For preventing oxidation and preventing deterioration over time: phenol-based, thio-based, phosphorus-based antioxidants and the like.
(7) Others: coloring agents, pigments, antistatic agents, antibacterial agents and the like.

When calcium carbonate is used, for example, in order to reduce flammability, the amount of the additive is preferably 10 to 40% by mass based on the oil substance having heat storage property due to phase change. .

An inclusion compound for adjusting the latent heat property may be added to the oily substance.
Examples of the clathrate _{compound, C 4 H 8 · O ·} 17H 2 O, (CH 3) 3 N · 10.25H 2 O, (C 4 H 9) 4 NCHO 2 · 32H 2 O, (C 4 H 9 ) ₄ NCH ₃ CO ₂ .32H ₂ O is preferred.

The preferred form of the heat storage body of the present invention is a form that does not include a crosslinked gel body containing an oily substance having a heat storage property due to a phase change or a substance encapsulated by a capsule coating. By not including such a crosslinked gel or a substance encapsulated by a capsule coating of an oily substance, the fluidity in the heat storage temperature range of the heat storage body is improved, and due to this, the heat transfer of the heat storage body is caused. It is possible to improve the performance and further reduce the load of the circulation pump that sends the heat storage body.
The crosslinked gel body containing an oily substance having heat storage property due to the phase change is a crosslinked gel body in which the oily substance is held inside the lipophilic polymer particles, that is, an aqueous solution containing a dispersant, the heat storage property by the phase change. And those obtained by adding and mixing a mixed solution of an oily substance and a monomer component containing a crosslinkable monomer. The one encapsulated by the capsule coating includes the encapsulation method by the complex emulsion method, the method of spraying the thermoplastic resin on the surface of the heat storage material particles, the method of forming the thermoplastic resin in the liquid on the surface of the heat storage material particles, the heat storage Examples thereof include those obtained by methods such as a method of polymerizing and coating a monomer on the surface of material particles and a method of producing a polyamide-coated microcapsule by an interfacial polycondensation reaction.

The regenerator of the present invention is also characterized in that the solidification / melting is repeated 50 times by phase change, and the change in the volume average particle diameter of the dispersion is smaller than the volume average particle diameter before the solidification / melting is repeated. Is preferably within ± 50%. By adopting such a configuration, it is possible to obtain a heat storage body that can be suitably used for the purpose of labor saving and efficiency of cooling and heating energy, environmental protection, and the like.
The above-mentioned repetition of solidification / melting refers to repetition of an operation of storing heat as latent heat in an oily substance having a heat storage property due to a phase change and releasing the stored heat.

In the repetition of coagulation / melting due to the phase change of the oily substance having a heat storage property, those having a volume average particle diameter change within the above range in 100 times or more are more preferable, and those in 200 times or more are more preferable. . In the repetition of solidification / melting of the oily substance, as the change in the volume average particle diameter of the dispersion becomes smaller, the destruction of the oily substance in the dispersion is suppressed, and the dispersion can be used stably for a long period of time.

As the repetition test of coagulation / melting due to the phase change of the oily substance, it is preferable to put a heat storage body in a sample bottle and perform a cycle test at a temperature at which coagulation / melting can be repeated by phase change. For example, when pentadecane having a melting point of 10 ° C. is used as an oily substance, and when solidification by phase change is performed, it can be performed by adjusting the temperature of the heat storage body to 5 to 7 ° C. Next, when performing melting, it can be implemented by adjusting the heat storage body by 12 to 15 ° C.

The change amount (%) of the volume average particle diameter is calculated as follows.
Change in volume average particle diameter (%) = (volume average particle diameter after 50 repeated solidification / melting operations-volume average particle diameter before repeated solidification / melting operation) / (volume average particle before repeated solidification / melting operation) Diameter) × 100
The volume average particle diameter is measured using a laser diffraction type particle size distribution analyzer SALD-3000 manufactured by Shimadzu Corporation. In addition, ion exchange water is used as a measurement medium.

As the heat storage material of the present invention, for example, a method in which an oily substance having heat storage property by phase change is added to an aqueous solution in which a surfactant and / or a polymer dispersant is dissolved in an aqueous medium and emulsified by stirring or the like, or It is preferable to add an aqueous material in which a polymer dispersant is dissolved in an aqueous medium, add an oily substance having a heat storage property by phase change in which a surfactant is dissolved, and emulsify by stirring or the like. Such a manufacturing method is one of preferred embodiments of the present invention.

In the heat storage body of the present invention, when having the above-described configuration, fluidity is improved, heat transfer performance is improved, and the stability of the emulsion can be improved. Can also exert the effects of the present invention.
That is, an oily substance having a heat storage property due to a phase change, an oil-in-water type dispersion for a heat storage material which essentially requires an aqueous medium, in a state where the oily substance in the oil-in-water type dispersion is solidified by the phase change. A heat storage material in which the amount of change in the volume average particle diameter of the oil-in-water dispersion when the shear by stirring is applied is within ± 50% of the volume average particle diameter before applying the shear is also This is one of the present invention.

The measurement of the change in the volume average particle diameter before and after the above-mentioned shearing is performed as follows.
(Test for applying shear force and method for measuring volume average particle size)
A test for applying a shearing force by stirring in a state where the oily substance in the dispersion is solidified by phase change is performed as follows.
As the stirring device, TK homomixer-M manufactured by Tokushu Kika Co., Ltd. is used. 200 g of the heat storage material is placed in a 500 ml beaker, and the temperature of the dispersion is adjusted to a temperature at which the solidification rate of the oily substance becomes 50 to 60%. After the temperature is adjusted, the TK homomixer is rotated at 4000 rpm and stirred. At the time of stirring, stirring is performed 2,000 times a number of times while maintaining the dispersion temperature from the stirring start temperature to the stirring start temperature + 0.5 ° C. After completion of the stirring, the volume average particle diameter of the dispersion is measured with a particle size distribution meter.

(Calculation method of coagulation rate of oily substance)
The solidification rate (%) of the oily substance is calculated as follows.
In calculating the solidification rate, a differential scanning calorimeter DSC-3100S manufactured by Mac Science Co., Ltd. is used. In the measurement, first, after cooling to a temperature of 25 to -20 ° C at a rate of 2 ° C / min, the temperature is increased to a temperature of -20 to 25 ° C at a rate of 2 ° C / min. The amount of latent heat at the time of freezing obtained at the time of this cooling is defined as the amount of latent heat of freezing at -20 ° C.
Next, the amount of latent heat during solidification is measured. Assuming that the temperature at which the solidification rate becomes 50 to 60% is A ° C., after cooling to 25 to A ° C. at a rate of 2 ° C./min, the temperature is maintained at A ° C. for 5 minutes. Thereafter, the temperature was raised to 25 ° C. at a rate of 2 ° C./min. Similarly, the amount of latent heat at the time of freezing obtained at the time of cooling is defined as the amount of latent heat of freezing at A ° C. 2.
The following equation is used as the equation for calculating the solidification rate.
Coagulation rate at A ° C. (%) = (latent heat of freezing at A ° C. 2) ÷ (latent heat of freezing at −20 ° C. 1) × 100
The DSC measurement conditions are for the case where the oil-in-water dispersion for heat storage material is used for cooling use. However, when the oil-in-water dispersion for heat storage material is used for heating use, the oily substance already solidifies at 25 ° C. It is possible that In that case, the DSC is started at a temperature at which the oily substance is sufficiently melted.

(Calculation method of volume average particle diameter change amount)
The change amount (%) of the volume average particle diameter is calculated as follows.
Change in volume average particle diameter (%) = (volume average particle diameter after applying shearing-volume average particle diameter before applying shearing force) / (volume average particle diameter before applying shearing) x 100
The volume average particle diameter is measured using a laser diffraction particle size distribution analyzer SALD-3000 manufactured by Shimadzu Corporation. In addition, ion exchange water is used as a measurement medium.
[Method of calculating the number of passes]
The following equation is used as the equation for calculating the number of passes.
Number of passes = 12.5 / processing amount (L) × processing time (minute)

The heat storage medium, when shearing by agitation in a state where the oily substance in the oil-in-water dispersion is solidified by phase change, the amount of change in the volume average particle diameter of the oil-in-water dispersion, Compared to the volume average particle size before applying shear, the volume average particle size is within ± 50%, but the change in volume average particle size is preferably within ± 20%, more preferably within 5%. It is what is. The smaller the change in the volume average particle diameter of the oil-in-water dispersion after the shearing is, the more the destruction of the oily substance in the dispersion is suppressed and the longer the dispersion can be used stably.

The oily substance having a heat storage property due to the phase change, in the oil-in-water dispersion for a heat storage material that essentially requires an aqueous medium, as a method for improving the dispersibility of the oily substance, the fluidity and the stability of the emulsion, for example, A method of dispersing an oily substance having a heat storage property by the phase change as described above by using a polymer dispersant together with a surfactant is exemplified.

In addition, oil-based substances having heat storage properties due to phase change, magnesium-, aluminum-, silicon-, phosphorus-, sulfur-, calcium-, scandium-, titanium-, vanadium-, chromium-, manganese-, iron- Examples include a method of including a metal such as cobalt, nickel, copper, zinc, gallium, and germanium.

Further, there is a method of dispersing an oily substance having heat storage property by a phase change using a specific nonionic surfactant. Examples thereof include polyoxyethylene (ethylene oxide added mole number of 20) alkyl such as polyoxyethylene (ethylene oxide added mole number of 30) stearyl ether and polyoxyethylene (ethylene oxide added mole number of 40) behenyl ether. (Number 15 or more) ether and / or polyoxyethylene (ethylene oxide added mole number 30) polyoxyethylene (ethylene oxide added mole number 20) such as sorbitan stearate or polyoxyethylene (ethylene oxide added mole number 40) sorbitan behenate Or more) those containing sorbitan (total carbon number 15 or more) ester as an essential component.

The machine used for emulsification in producing the heat storage body is not limited, and a general machine can be used. For example, propeller stirrer, high-speed rotary stirrer, homomixer, high-pressure homogenizer, colloid mill, roll mill, roller mill, sand mill, ball mill, in-line (power type, non-power type) continuous emulsifier, ultrasonic emulsifier, vacuum kneading Machine, vacuum emulsifier and open emulsifier.

The use form of the heat storage body of the present invention is preferably in the form of an emulsion-like water dispersion, or may be used as a heat storage body in a form filled in a packaging material.
The heat storage material of the present invention is used in various heat storage devices in the form of such an emulsified product or a packaged state. As such a heat storage device, (1) a heat storage material is used as a heat transfer medium. And (2) a device provided with a heat storage tank for storing a heat storage body and capable of performing heat exchange of a heat medium.

As the heat storage device of the above (1), a heat storage device using a water storage material dispersed in water is preferable, and the heat storage device circulates between the heat storage tank and the heat exchanger, or circulates outside the heat storage tank. Thus, a heat storage device that exchanges heat is used, and such a heat storage device forms a heat storage system that is a heat transfer medium system for a district cooling / heating system or a building air conditioning system.

The heat storage device of the above (2) is provided with a heat storage tank in which the heat storage material is stored, and can perform heat exchange of the heat medium. However, a heat storage device storing the heat storage material is preferable. Such a heat storage device also forms a heat storage system.
As the heat storage device that stores the heat storage body, a device that is capable of transferring heat energy to and from a heat medium circulating outside the heat storage device by including a heat exchange unit in the heat storage tank is preferable. A heat exchanger that exchanges heat medium in a heat storage tank in which a heat storage element is stored, or only a heat medium passes through a heat storage tank while an emulsion-like aqueous dispersion is stored in the heat storage tank. And the like.
A heat storage device or a heat storage system using such a heat storage body of the present invention is also one of the present invention.

The heat storage body of the present invention has the above-described structure, and contains a polymer dispersant, whereby the dispersibility of an oily substance is increased, the fluidity is improved, the heat transfer performance is improved, and the stability of the emulsion is improved. It is easy to adjust the freezing point and improve the heat storage efficiency, or because the freezing temperature and the melting temperature are close, it is easy to solidify at the time of heat storage and it is possible to lower the temperature at the time of heat release, and the amount of latent heat And the heat storage performance is improved. In addition, as a material constituting a heat storage device or a heat storage system that can be suitably used for the purpose of energy saving and efficiency of cooling and heating energy for large buildings such as office buildings and factories, and for home use, etc. It is excellent.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to only these Examples. Unless otherwise specified, “parts” means “parts by weight” and “%” means “% by mass”.

Example 1
1.5 parts of polyoxyethylene stearyl ether (Nonion S-220, manufactured by NOF Corporation) as a nonionic surfactant and 0.5 parts of polyvinylpyrrolidone (manufactured by Nippon Shokubai Co., Ltd., molecular weight of about 120,000) in a beaker. Was added to 47.5 parts of water and dissolved in an aqueous solution and paraffin distilled from kerosene as an oily substance (tetradecane 19.4% by mass, pentadecane 73.5% by mass, hexadecane 6.9% by mass, heptadecane 0.2% by mass) ) A solution prepared by dissolving 0.5 part of sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts was added. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thereby, the heat storage body (aqueous dispersion) 1 according to the present invention was obtained.
The solidification temperature was determined by performing differential scanning calorimetry (DSC) on the obtained heat storage body 1 under predetermined conditions. For differential scanning calorimetry (DSC), a differential scanning calorimeter DSC-3100S manufactured by Mac Science was used. As 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 6.5 ° C. The fluidity of the heat storage body 1 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 1 was measured using a particle size distribution meter. As the particle size distribution meter, a laser diffraction type particle size distribution measuring device SALD-3000 manufactured by Shimadzu Corporation was used. The volume average particle diameter of the heat storage body 1 was 2.94 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. Coagulation / melting was repeated 300 times, and the volume average particle diameter was measured to be 2.90 μm. The change in the volume average particle diameter of the dispersion was as small as -1%, and the heat storage material was stable even after repeated coagulation / melting.

Example 2
1.5 parts of polyoxyethylene stearyl ether (Nonion S-220, manufactured by NOF Corporation) as a nonionic surfactant and polyvinyl alcohol (GOHSENOL KH-20, manufactured by Nippon Gosei Co., Ltd., molecular weight of about 100,000 as a polymer dispersant in a beaker. ) Was added to 47.95 parts of water and dissolved in water, and paraffin (19.4% by mass of tetradecane, 73.5% by mass of pentadecane, 6.9% by mass of hexadecane) distilled from kerosene as an oily substance. A solution prepared by dissolving 0.5 part of sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts of pentadecane (0.2% by mass) was added. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thereby, the heat storage body (water dispersion) 2 according to the present invention was obtained.
The solidification temperature was obtained by performing differential scanning calorimetry (DSC) on the obtained heat storage body 2 under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 7.2 ° C. The fluidity of the heat storage body 2 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 2 was similarly measured using a particle size distribution meter. The heat storage body 2 had a volume average particle diameter of 3.02 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. Coagulation / melting was repeated 190 times, and the volume average particle size was measured to be 2.99 μm. The change in the volume average particle diameter of the dispersion was as small as -1%, and the heat storage material was stable even after repeated coagulation / melting.

Example 3
1.5 parts of polyoxyethylene stearyl ether (Nonion S-220, manufactured by NOF Corporation) as a nonionic surfactant and sodium polyacrylate (Aqualic IH-L, manufactured by Nippon Shokubai Co., Ltd., molecular weight as a polymer dispersant in a beaker An aqueous solution obtained by adding 0.05 parts of about 1.5 million parts of water to 47.95 parts of water and paraffin (19.4% by mass of tetradecane, 73.5% by mass of pentadecane, 6.9% by mass of hexadecane) distilled from kerosene as an oily substance. %, Heptadecane 0.2% by mass) and a solution prepared by dissolving 0.5 part of sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thus, the heat storage body (water dispersion) 3 according to the present invention was obtained.
The solidification temperature was determined by performing differential scanning calorimetry (DSC) on the obtained heat storage body 3 under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 6.5 ° C. The fluidity of the heat storage body 3 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 3 was similarly measured using a particle size distribution meter. The volume average particle diameter of the heat storage body 3 was 3.16 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. Coagulation / melting was repeated 190 times, and the volume average particle diameter was measured to be 3.36 μm. The change in the volume average particle diameter of the dispersion was as small as + 6%, and the heat storage material was stable even after repeated coagulation / melting.

Example 4
1.5 parts of polyoxyethylene stearyl ether (Nonion S-220, manufactured by NOF Corporation) as a nonionic surfactant and sodium polyacrylate (Aqualic DL522, manufactured by Nippon Shokubai Co., Ltd., molecular weight of about 17 as a polymer dispersant in a beaker. Paraffin (19.4% by mass of tetradecane, 73.5% by mass of pentadecane, 6.9% by mass of hexadecane) distilled from an aqueous solution prepared by adding 0.5 parts to 47.5 parts of water and dissolving an aqueous solution and kerosene as an oily substance. And a solution prepared by dissolving 0.5 part of sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts of heptadecane. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thereby, the heat storage body (water dispersion) 4 according to the present invention was obtained.
The solidification temperature was obtained by performing differential scanning calorimetry (DSC) on the obtained heat storage body 4 under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 6.9 ° C. The fluidity of the heat storage body 4 at 5 ° C. was good.
The volume average particle diameter of the heat storage 4 was similarly measured using a particle size distribution meter. The volume average particle diameter of the heat storage body 4 was 2.64 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. Coagulation / melting was repeated 70 times, and the volume average particle size was measured to be 2.70 μm. The change in the volume average particle size of the dispersion was as small as + 2%, and the heat storage material was stable even after repeated coagulation / melting.

Example 5
1.5 parts of polyoxyethylene stearyl ether (Nonion S-220, manufactured by NOF Corporation) as a nonionic surfactant and polyethyleneimine (Epomin P-1000, manufactured by Nippon Shokubai Co., Ltd., molecular weight of about 70,000 as a polymer dispersant in a beaker. ) 0.5 part of water was added to 47.5 parts of water, and paraffin distilled from an aqueous solution dissolved and kerosene as an oily substance (tetradecane 19.4% by mass, pentadecane 73.5% by mass, hexadecane 6.9% by mass, heptadecane) A solution obtained by dissolving 0.5 part of sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts of 0.2% by mass was added. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thereby, the heat storage body (water dispersion) 5 according to the present invention was obtained.
The solidification temperature was obtained by performing differential scanning calorimetry (DSC) on the obtained heat storage body 5 under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 6.9 ° C. The fluidity of the heat storage body 5 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 5 was similarly measured using a particle size distribution meter. The volume average particle diameter of the heat storage body 5 was 2.64 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. Coagulation / melting was repeated 70 times, and the volume average particle diameter was measured to be 2.71 μm. The change in the volume average particle size of the dispersion was as small as + 3%, and the heat storage material was stable even after repeated coagulation / melting.

Example 6
1.5 parts of polyoxyethylene sorbitan alkyl ester (manufactured by Kao Corporation: Rheodol Super TWL-120) as a nonionic surfactant and hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd .: HiMetroze hi90SH100000) as a nonionic surfactant. 005 parts was added to 47.995 parts of water, and paraffin (19.4% by mass of tetradecane, 73.5% by mass of pentadecane, 6.9% by mass of hexadecane, 0% by mass of heptadecane) was distilled from an aqueous solution dissolved and kerosene as an oily substance. A solution in which 0.5 part of a sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved was added to 50.0 parts of the mixture. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thus, a heat storage body (water dispersion) 6 according to the present invention was obtained. The solidification temperature was obtained by performing differential scanning calorimetry (DSC) on the obtained heat storage body 6 under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 7.9 ° C. The fluidity of the heat storage body 6 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 6 was similarly measured using a particle size distribution meter. The volume average particle diameter of the heat storage body 6 was 3.09 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. The solidification / melting was repeated 150 times, and the heat storage material was stable even after the solidification / melting was repeated.

Example 7
1.5 parts of polyoxyethylene sorbitan stearate (manufactured by Kao Corporation: Rheodol TW-S120V) as a nonionic surfactant, and sodium polyacrylate (aqualic IH-L) manufactured by Nippon Shokubai Co., Ltd. Paraffin (19.4% by weight of tetradecane, 73.5% by weight of pentadecane, 6.9% by weight of hexadecane, and 0.9% by weight of heptadecane) was added to 47.9 parts of water and dissolved in 47.9 parts of water and distilled from kerosene as an oily substance. A solution obtained by dissolving 0.5 part of sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts of 2 wt%) was added. The mixture was emulsified using a stirrer (TK homomixer-M type, manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. To this aqueous dispersion, 66.7 parts of ion-exchanged water was added, whereby a heat storage material (aqueous dispersion) 7 according to the present invention was obtained.
The solidification temperature was obtained by performing differential scanning calorimetry (DSC) on the obtained heat storage body 7 under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 7.3 ° C. The fluidity of the heat storage body 7 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 7 was similarly measured using a particle size distribution meter. The volume average particle diameter of the heat storage body 7 was 3.03 μm when measured using a laser diffraction type particle size distribution analyzer SALD-3000 manufactured by Shimadzu Corporation.
Next, an experiment in which shearing by stirring was performed was performed.
200 g of the heat storage element 7 was placed in a 500 ml beaker, and the material temperature was cooled to 5 ° C. The solidification rate of the oily substance at 5 ° C. was 57% when calculated by a predetermined method using a differential scanning calorimeter DSC-3100S manufactured by Mac Science. After the temperature was adjusted to 5 ° C., the mixture was dispersed by using a stirrer TK homomixer Model M at a rotation speed of 4000 rpm. At the time of stirring, stirring was performed 2,000 times while maintaining the dispersion temperature at 5 ° C. to 5.5 ° C. After completion of the stirring, the volume average particle diameter of the heat storage body 7 was measured using a particle size distribution meter in the same manner, and it was 3.46 μm. The variation in the volume average particle size of the dispersion was as small as + 14%, and was stable even when a shearing force due to stirring was applied.

Example 8
To a beaker, 1.5 parts of polyoxyethylene benzyl ether (Nonion B-240, manufactured by NOF CORPORATION, 40 moles of ethylene oxide added) as a nonionic surfactant was added to 48.0 parts of water and dissolved in an aqueous solution and oiliness. 50.0 parts of paraffin (19.4% by weight of tetradecane, 73.5% by weight of pentadecane, 6.9% by weight of hexadecane, 0.2% by weight of heptadecane) distilled from kerosene as a substance is added to a sucrose fatty acid ester (Daiichi Kogyo Co., Ltd.). A liquid in which 0.5 part of Sugar Wax A-10E manufactured by Pharmaceutical Company was dissolved was added. The mixture was emulsified using a stirrer (TK homomixer-M type, manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thus, a heat storage body (aqueous dispersion) 8 according to the present invention was obtained. The fluidity of the heat storage body 8 at 5 ° C. was good.
The volume average particle diameter of the heat storage body 8 was similarly measured using a particle size distribution meter. The volume average particle diameter of the heat storage body 8 was 2.86 μm when measured using a laser diffraction type particle size distribution analyzer SALD-3000 manufactured by Shimadzu Corporation.
Next, an experiment in which shearing by stirring was performed was performed.
200 g of the heat storage body 8 was placed in a 500 ml beaker, and the material temperature was cooled to 5 ° C. The solidification rate of the oily substance at 5 ° C. was 57% when calculated by a predetermined method using a differential scanning calorimeter DSC-3100S manufactured by Mac Science. After the temperature was adjusted to 5 ° C., the mixture was dispersed by using a stirrer TK homomixer Model M at a rotation speed of 4000 rpm. At the time of stirring, stirring was performed 2,000 times while maintaining the dispersion temperature at 5 ° C. to 5.5 ° C. After the stirring was completed, the volume average particle diameter of the heat storage body 8 was measured by a particle size distribution analyzer in the same manner, and it was 3.32 μm. The variation in the volume average particle diameter of the dispersion was as small as + 16%, and was stable even when a shearing force due to stirring was applied.

Comparative Example 1
To a beaker was added 1.5 parts of polyoxyethylene sorbitan alkyl ester (manufactured by Kao Corporation: Leodol Super TWL120) as a nonionic surfactant in 48.0 parts of water, and a dissolved aqueous solution and paraffin distilled from kerosene as an oily substance. (19.4% by mass of tetradecane, 73.5% by mass of pentadecane, 6.9% by mass of hexadecane, 0.2% by mass of heptadecane) and 50.0 parts of sucrose fatty acid ester (Sugar Wax A- manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10E) A solution in which 0.5 part was dissolved was added. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. Thus, a comparative heat storage body 1 (aqueous dispersion) was obtained.
The solidification temperature of the obtained comparative heat storage body 1 was determined by performing differential scanning calorimetry (DSC) under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 6.8 ° C. The fluidity at 5 ° C. of the comparative heat storage body 1 was good.
The volume average particle diameter of the comparative heat storage body 1 was measured using a particle size distribution meter. As the particle size distribution meter, a laser diffraction type particle size distribution measuring device SALD-3000 manufactured by Shimadzu Corporation was used. The volume average particle diameter of the comparative heat storage body 1 was 3.14 μm.
In addition, the solidification of the oily substance was performed at 5 ° C., and the solidification / melting of melting at 12 ° C. was repeated. When the coagulation / melting was repeated 72 times, part of the paraffin separated into layers.
Similarly, when an experiment was performed in which shearing was performed by stirring at 5 ° C., the material became whipped at the 1,000th pass and fluidity was not observed. After the completion of the stirring, the volume average particle diameter of the comparative heat storage body 1 was as large as 9.67 μm. The variation in the volume average particle size of the dispersion was as large as + 208%, and was unstable due to the shearing force caused by stirring.

Comparative Example 2
In a beaker, 1.5 parts of polyvinylpyrrolidone (manufactured by Nippon Shokubai Co., Ltd .; molecular weight: about 120,000) was added as a polymer dispersant to 48.0 parts of water, and an aqueous solution of the solution was dissolved. Sucrose fatty acid ester (Sugar Wax A-10E, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 50.0 parts by mass (% by mass, pentadecane 73.5% by mass, hexadecane 6.9% by mass, heptadecane 0.2% by mass). A solution in which 0.5 part was dissolved was added. Emulsification was performed using a stirrer (TK homomixer manufactured by Tokushu Kika Co., Ltd.), but an aqueous dispersion in which paraffin was dispersed could not be obtained.

Comparative Example 3
1.5 parts of polyoxyethylene sorbitan stearate (manufactured by Kao Corporation: Rheodol TW-S120V) as a nonionic surfactant in a beaker, and an aqueous solution dissolved in 48.0 parts of water and dissolved therein and paraffin distilled from kerosene as an oily substance. (19.4% by weight of tetradecane, 73.5% by weight of pentadecane, 6.9% by weight of hexadecane, 0.2% by weight of heptadecane) and 50.0 parts of sucrose fatty acid ester (Sugar wax A- manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10E) A solution in which 0.5 part was dissolved was added. The mixture was emulsified using a stirrer (TK homomixer-M type, manufactured by Tokushu Kika Co., Ltd.). An aqueous dispersion in which paraffin was dispersed was obtained. To this aqueous dispersion, 66.7 parts of ion-exchanged water was added, thereby obtaining a comparative heat storage material (aqueous dispersion) 3 according to the present invention.
The solidification temperature of the obtained comparative heat storage body 3 was determined by performing differential scanning calorimetry (DSC) under predetermined conditions. As a result, the solidification temperature (solidification start temperature) was 7.4 ° C.
The fluidity at 5 ° C. of the comparative heat storage body 3 was good.
The volume average particle diameter of the comparative heat storage body 3 was 2.84 μm.
Next, an experiment in which shearing by stirring was performed was performed.
200 g of the comparative regenerator 3 was placed in a 500 ml beaker, and the material temperature was cooled to 5 ° C. The solidification rate of the oily substance at 5 ° C. was 57% when calculated by a predetermined method using a differential scanning calorimeter DSC-3100S manufactured by Mac Science. After the temperature was adjusted to 5 ° C., the mixture was dispersed by using a stirrer TK homomixer Model M at a rotation speed of 4000 rpm. At the time of stirring, stirring was performed 2,000 times while maintaining the dispersion temperature at 5 ° C. to 5.5 ° C. The volume average particle diameter of the comparative heat storage body 3 after completion of the stirring was as large as 6.15 μm. The volume average particle diameter variation of the dispersion was as large as + 117%, and was unstable due to shearing force due to stirring.

Claims (4)

A heat storage element comprising a dispersion obtained by dispersing a mixture essentially comprising an oily substance having a heat storage property by a phase change, an aqueous medium, a surfactant and a polymer dispersant in an oil-in-water type. The heat storage body according to claim 1, wherein the surfactant comprises a nonionic surfactant as an essential component. An oily substance having heat storage property by phase change, an oil-in-water dispersion for a heat storage material essentially comprising an aqueous medium, wherein the oily substance in the oil-in-water dispersion is solidified by phase change by stirring. A heat storage element characterized in that the amount of change in the volume average particle diameter of the oil-in-water dispersion when subjected to shearing is within ± 50% of the volume average particle diameter before applying shearing. . A heat storage device and a heat storage system using the heat storage body according to claim 1.