Heat storage resistor

Abstract

This heat storage resistor comprises latent heat storage particles and a solid medium, and has an electric resistivity within the range of 1 × 10-7 to 3 × 103 Ω·cm, wherein: the latent heat storage particles each have a core particle and a coating part that covers at least part of the surface of the core particle; the core particle has, as a component thereof, a certain element or the like, and has a melting point of 100°C or higher; and the coating part has, as a component thereof, an element or the like that is different from the component of the core particle, does not cause chemical reaction with the core particle in an operation temperature range, and has an electric resistivity within the range of 1 × 10-7 to 3 × 103Ω·cm.

Description

Heat storage resistor

[0001] The present disclosure relates to a heat storage resistor.

[0002] Development of energy storage technologies for storing renewable energy, such as that obtained from solar power generation and wind power generation, is underway to ensure its availability when needed. For example, Non-Patent Document 1 describes an electric thermal energy storage system that includes a heater and a thermal storage tank. It shows that using a synchronous rotary heater as the heater has many advantages. Specifically, it shows that a synchronous rotary heater can achieve cheaper electric thermal energy storage and has the ability to generate fault currents for synchronous inertia and power system protection systems, which eliminates the need for auxiliary power system stabilization systems such as rotating capacitors.

[0003] T. Okazaki, Electric thermal energy storage and advantage of rotating heater having synchronous inertia, Renew. Energ., 151 (2020) 563-574

[0004] In the technology of Non-Patent Document 1 and the like, thermal energy obtained by a heater is converted into electrical energy and stored in a heat storage tank, and can be converted back into thermal energy or the like from the heat storage tank as needed, but such multiple conversions are prone to energy loss. The present disclosure has been made in consideration of such circumstances, and its purpose is to provide a heat storage resistor that has both the function of a resistor that generates thermal energy when current is applied and the function of a heat storage that can store the thermal energy.

[0005] Aspect 1 of the present invention is a method for manufacturing a latent heat storage medium comprising latent heat storage particles and a solid medium, the method comprising: －７ ~3 x 10 ３a heat storage resistor having a resistance in the range of Ω cm, wherein the latent heat storage particles have a core particle and a coating portion that coats at least a part of the surface of the core particle, and the components of the core particle are one or more selected from the group consisting of elements selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd, alloys containing the elements as main components, compounds containing the elements, and carbonates, hydroxides, (nitro)oxides, and halides of alkali metals and / or alkaline earth metals, and the melting point is 100° C. or higher, The component of the coating portion is one or more selected from the group consisting of elements, alloys containing the elements, inorganic compounds selected from the group consisting of zinc oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, and molybdenum disilicide, which do not undergo a chemical reaction with the core particle in the temperature range of operation, and mixtures thereof, and has an electrical resistivity of 1×10 －７ ~3 x 10 ３ It is a heat storage resistor having a resistance in the range of Ω·cm.

[0006] A second aspect of the present invention is the heat storage resistor according to the first aspect, wherein the alloy component of the coating portion is one or more of a Kanthal alloy and a Nichrome alloy.

[0007] A third aspect of the present invention is the heat storage resistor according to the first or second aspect, wherein the ratio of the latent heat storage particles in the heat storage resistor is 10 to 90% by volume.

[0008] A fourth aspect of the present invention is the heat storage resistor according to any one of the first to third aspects, wherein the average particle size of the core particles is 10 μm or more and 200 μm or less.

[0009] According to the present disclosure, it is possible to provide a heat storage resistor that has both a function as a resistor that generates heat energy when current is passed through it and a function as a heat storage body that can store the heat energy.

[0010] 1 is a diagram schematically illustrating a high-speed airflow impact device that can be used to manufacture latent heat storage particles. FIG. 1 shows XRD (X-ray Diffraction) measurement results for latent heat storage particles in an example. FIG. 2 is a SEM (Scanning Electron Microscope)-EDS (Energy Dispersive X-ray Spectroscopy) photograph of latent heat storage particles in an example. FIG. 3 is a top view photograph of a sample before and after sintering in an example. FIG. 4 shows XRD measurement results for a heat storage resistor 1 in an example. FIG. 5 is a SEM-EDS photograph of a heat storage resistor 1 in an example. FIG. 6 is a photograph of an apparatus used in an energization experiment in an example. FIG. 7 shows conditions and experimental results for an energization experiment in an example. FIG. 8 shows differential scanning calorimetry results for a sample in an example. FIG. 9 shows energization experiment results for a heat storage resistor 2 in an example. FIG. 10 shows energization experiment results for a heat storage resistor 3 in an example. FIG. 11 shows energization experiment results for a heat storage resistor 4 in an example. FIG. 12 shows energization experiment results for a heat storage resistor 5 in an example. FIG. 10 is a diagram showing the results of an experiment in which a thermal storage resistor 6 is energized in an example.

[0011] As a result of extensive research, the present inventors have found that a heat storage resistor that can generate and store thermal energy can be realized by including latent heat storage particles having a predetermined core-shell structure and exhibiting a predetermined electrical resistivity. In this specification, the term "heat storage resistor" refers to a resistor that is capable of resistance heating (generating heat when current is applied) and storing heat. The heat storage resistor according to the present disclosure will be described below.

[0012] [Heat Storage Resistor] The heat storage resistor of the present disclosure contains latent heat storage particles and a solid medium, and has an electrical resistivity of 1×10 －７ ~3 x 10 ３ The thermal storage resistor exhibiting an electrical resistivity in this range is MoSi, which exhibits the lowest electrical resistivity as a heater material. ２The latent heat storage resistor can be used as a heating resistor to replace a heater using a latent heat storage particle or as a resistor with a sufficiently high electrical resistivity. The electrical resistivity is measured by the method described in the examples below. The electrical resistivity of the heat storage resistor can be appropriately selected depending on the application within the above range of electrical resistivity. Below, the latent heat storage particles and solid medium that constitute the heat storage resistor exhibiting the above electrical resistivity will be described.

[0013] (Latent Heat Storage Particles) The latent heat storage particles contained in the heat storage resistor of the present disclosure have a core particle and a coating portion (also referred to as a "shell") that covers at least a part of the surface of the core particle. The core particle and the coating portion will be described below.

[0014] [Core Particle] The core particle is composed of one or more elements selected from the group consisting of: (i) an element selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd; (ii) an alloy containing the above element as a main component; (iii) a compound containing the above element; (iv) an alkali metal carbonate, hydroxide, (nitrite) oxide (i.e., nitrite oxide, nitrate), and halide; and (v) an alkaline earth metal carbonate, hydroxide, (nitrite) oxide (i.e., nitrite oxide, nitrate), and halide (which may overlap with the Mg-containing compound in (i) above).

[0015] Examples of the halide include fluorides, chlorides, bromides, iodides, and astatides. The term "main component" refers to a proportion of the core particle that is 50% by mass or more. The material constituting the core particle is a latent heat storage material, also known as a phase change material (PCM). A latent heat storage material (hereinafter sometimes referred to as "PCM") utilizes the latent heat of solid-liquid phase change. By storing latent heat through the latent heat of fusion and releasing heat through the latent heat of solidification, it is possible to store heat at a higher density than latent heat storage technologies that use sensible heat. Furthermore, since PCMs can store and release latent heat at a constant temperature (the melting point of the PCM), they can be used as a constant-temperature heat source. Furthermore, the melting point of the components of the core particle is 100°C or higher. This allows for the coating portion to be formed smoothly during the production of latent heat storage particles, for example, without melting the core particles. In one embodiment, the melting point of the components of the core particle is lower than the melting point of the components of the coating portion, for example, 2000°C or lower, for example, 1500°C or lower, for example, 1000°C or lower.

[0016] As described above, the core particle may be composed of an element selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd, an alloy mainly composed of the element, or a compound containing the element. Preferably, the core particle is composed of an element selected from the group consisting of Al, Mg, Zn, Sb, Pb, and Cd, an alloy mainly composed of the element, or a compound containing the element. The alloy may contain, in addition to the main element, one or more alloying elements selected from the group consisting of Si, Ti, Fe, Ni, Cu, Sn, Ga, In, and Bi.

[0017] One of the more preferred components of the core particle is the above-mentioned alloy of Zn and Al (Zn-Al alloy). In this case, the Al content is not particularly limited as long as it is more than 0 mass% and less than 100 mass%. The Al content may be 50 mass% or less. For example, a latent heat storage material having a core of a Zn-10 mass% Al alloy has a melting point of about 380°C, and a latent heat storage material having a core of a Zn-30 mass% Al alloy has a melting point of 417°C or higher, particularly 429°C or higher and 516°C or lower.

[0018] The average particle diameter of the core particles may be 10 μm or more and 200 μm or less. According to this embodiment, micro-order latent heat storage particles (microencapsulated PCM, also referred to as "MEPCM") can be realized in which the core particles (PCM) contain the above components. The average particle diameter may be, for example, 100 μm or less, or even 50 μm or less. In this specification, the "average particle diameter" of the core particles and the core raw material particles and child particles described below is a value measured using a laser diffraction particle size distribution analyzer (e.g., HORIBA LA-920). More specifically, the volume distribution of the particle group is measured using a laser diffraction particle size distribution analyzer, and the cumulative 50% by volume diameter value (D50) is regarded as the average particle diameter. The average particle diameter of the core particles constituting the latent heat storage particles may be approximately the same as or smaller than the average particle diameter of the core raw material particles used in the production of the latent heat storage particles. According to this embodiment, the latent heat storage particles need only have a core-shell structure, and even if, during the manufacturing stage or use of the latent heat storage particles, a portion of the surface of the core raw particle reacts with, for example, a child particle or the outside air, and, for example, a portion of the surface of the core raw particle made of metal is converted into an oxide, and some of the metal constituting the core raw particle is consumed, the latent heat storage particles can still function as latent heat storage particles as long as the core-shell structure is maintained.

[0019] [Covering portion (shell portion)] The components of the covering portion have a higher melting point than the components of the core particle and are different from the components of the core particle, and are one or more selected from the group consisting of: (I) elements (e.g., elements selected from the group consisting of C, Mo, Al, Mg, Si, Ti, Fe, Ni, Cu, Cr, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd); (II) alloys containing the elements; (III) one or more inorganic compounds selected from the group consisting of zinc oxide, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, and molybdenum disilicide; and (IV) mixtures thereof, and are composed of a component that does not chemically react with the components of the core particle in the operating temperature range. Furthermore, the components of the covering portion, i.e., the covering portion itself, have an electrical resistivity of 1×10 －７ ~3 x 10 ３The electrical resistivity is in the range of Ω·cm. By enclosing the core particles within the coating, leakage of the PCM that melts and becomes liquid during latent heat storage can be prevented. Furthermore, by having the coating exhibit the above electrical resistivity, a heat storage resistor exhibiting a predetermined electrical resistivity can be realized. The above-mentioned "operating temperature" refers to the heating temperature of the latent heat storage particles, and can be selected, for example, within the range of 200°C to 800°C depending on the application.

[0020] As described above, the element (I) may be an element selected from the group consisting of C, Mo, Al, Mg, Si, Ti, Fe, Ni, Cu, Cr, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd.

[0021] The alloy (II) may be an alloy containing an element selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Cr, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd as a main component, and the alloy component is preferably one or more of a Kanthal alloy and a nichrome alloy.

[0022] The inorganic compound (III) also includes a mixture of two or more different inorganic compounds. The inorganic compound includes ceramics, glass, and α-Al by firing. ２ O ３ The ceramics may include one or more selected from the group consisting of ZnO (zinc oxide), α-Al ２ O ３ , θ-Al ２ O ３ Alumina (aluminum oxide), aluminum nitride, zirconia, silicon nitride, SiO ２ The inorganic compound is preferably at least one selected from the group consisting of zinc oxide, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, and molybdenum disilicide, or a composite thereof. The α-alumina precursor can be converted into α-Al by firing at a temperature of, for example, 880°C or higher. ２ O ３The α-alumina precursor is an Al-containing compound, specifically an Al-containing oxide and / or an Al-containing hydroxide, more specifically AlOOH and / or Al(OH). ３ The coating component is Al, α-Al ２ O ３ , AlOOH, Al(OH) ３ and glass.

[0023] When the core particle is a metal or alloy and the coating is ceramic, the metal contained in the core particle and the metal element contained in the ceramic that constitutes the coating may be the same or different. For example, when the core particle is an Al alloy and the coating is an Al oxide, the component of the coating is an oxide that is different from the alloy that constitutes the core particle, but the metal Al contained in the core particle and the metal element (Al) contained in the oxide as the ceramic that constitutes the coating are the same.

[0024] The component of the coating portion is more preferably one or more selected from the group consisting of zinc oxide, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, Kanthal alloy, nichrome alloy, and molybdenum disilicide.

[0025] The coating portion of the latent heat storage particles according to this embodiment may have a thickness in the range of 200 nm to 5 μm. The coating portion may be, for example, a coating layer having a thickness of 1 to 2 μm.

[0026] The coating portion of the latent heat storage particle according to this embodiment only needs to cover at least a portion of the surface of the core particle. The coverage of the coating portion on the surface of the core particle is preferably 50 area% or more. The coverage is more preferably 70 area% or more, even more preferably 80 area% or more, even more preferably 90 area% or more, and most preferably 100 area%. In the latent heat storage particle according to this embodiment, the core particle may be tightly covered with the components of the coating portion to form a dense shell. As long as the coverage satisfies the preferred coverage range, it is acceptable for the core particle to be uncovered with the components of the coating portion and have scattered exposed portions. It is also acceptable for nano-level gaps, for example, to exist due to the accumulation of child particles used in the production of the latent heat storage particle. Even if the core particle has exposed portions or gaps, it is believed that deterioration of the core particle during use can be prevented. For example, in the case of a core particle made of metal, oxides are formed on exposed portions of the core particle exposed to the outside air, which is believed to prevent deterioration due to metal consumption of the core particle.

[0027] When the latent heat storage particles according to this embodiment are produced by hybridization, which involves adhering daughter particles to the surface of core raw material particles, at least a portion of the coating portion may have a particle shape due to the hybridization. That is, the coating portion may have at least a particulate-shaped portion. The particle shape of at least a portion of the coating portion may be derived from the daughter particles used in the production of the latent heat storage particles. Latent heat storage particles produced by hybridization differ from latent heat storage particles produced, for example, by a wet method in that at least a portion of the coating portion has a particle shape. The particle shape of at least a portion of the coating portion can be confirmed regardless of whether or not the heat treatment described below is performed, and can be confirmed in at least the outermost surface region of the coating portion even if the heat treatment described below is performed. The particle shape of at least a portion of the coating portion may be an aggregate of particles, and may be an aggregate of the daughter particles used in the production of the latent heat storage particles. Therefore, the phrase "at least a part of the coating portion is in a particulate shape" means that when observed with a scanning electron microscope at a magnification of 10,000 times, at least 10 particles (some of which may be joined to other particles) are confirmed.

[0028] At least a portion of the particulate-shaped portions of the coating portion may have an average particle diameter of 0.1 μm or more and 2 μm or less. This average particle diameter refers to the average equivalent circle diameter of at least 10 particles observed with the electron microscope. The region of the coating portion other than the at least a portion of the particulate-shaped portions may be a porous or dense solid layer formed, for example, by melting and agglomerating child particles.

[0029] The coating portion may contain one or more (core particle-derived components) selected from the group consisting of elements constituting the core particle, alloys containing the elements, inorganic compounds containing the elements, and mixtures thereof. As described above, elements constituting the core particle include elements selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd. Examples of the inorganic compound include ceramics containing the elements and glasses containing the elements. The core particle-derived component contained in the coating portion only needs to contain the elements constituting the core particle, and the form of the core particle-derived component may be the same as or different from that of the core particle component. An example of a case where the forms of the two are different is when the core particle component is a metal and the core particle-derived component is an oxide of the metal.

[0030] The term "contains" a core particle-derived component in the coating portion means that at least a portion of the core particle-derived component is in contact with the component that constitutes the coating portion, and examples thereof include the case where the entire core particle-derived component is covered with the component that constitutes the coating portion, or the case where a portion of the core particle-derived component is covered with the component that constitutes the coating portion, and the other portion of the core particle-derived component is exposed to the outside air (for example, the case where the core particle-derived component is in contact with a portion of the surface of the coating portion).

[0031] The shape of the latent heat storage particles is not limited to a spherical shape, but may also be polygonal, rugby ball-shaped, disc-shaped, or cylindrical.

[0032] The ratio of the latent heat storage particles in the heat storage resistor is 10 to 90% by volume. From the viewpoint of ensuring the storage of thermal energy, the ratio of the latent heat storage particles in the heat storage resistor is preferably 10% by volume or more, more preferably 30% by volume or more. On the other hand, from the viewpoint of including the solid medium described below, the ratio of the latent heat storage particles in the heat storage resistor is preferably 90% by volume or less, more preferably 80% by volume or less.

[0033] (Solid medium) The heat storage resistor includes a solid medium. The solid medium may be any medium that does not significantly adversely affect the performance of the latent heat storage particles at the operating temperature and can maintain the latent heat storage particles dispersed. Examples of the solid medium include glass frit, Li ２ O, Na ２ O, and K ２ Alkali silicates containing one or more of O, colloidal silica, organic metal siliconates, acidic metal phosphates which are phosphates of acidic metals such as Al, Mg, Ca, Fe, and Zn, polyvalent metal alcoholates which are alcoholates of polyvalent metals such as Al, Sn, Ti, and Zr, organopolysiloxanes such as alkyl silicates, alumina sol, synthetic mica, phosphonitrile chloride, alumina cement, metal oxides such as ZnO, graphite including expanded graphite, carbides such as SiC, MoSi ２ Examples include intermetallic compounds such as those mentioned above, and one or more of these may be used. The solid medium may be a material different from the components of the coating portion of the latent heat storage particles. The inclusion of the solid medium can adjust the electrical resistivity of the heat storage resistor, contribute to the dispersion of the latent heat storage particles in the heat storage resistor, and ultimately contribute to the formation of a conductive network due to the arrangement of the latent heat storage particles. The proportion of the solid medium contained in the heat storage resistor (which may be the blending ratio at the time of blending) may be, for example, 80% by volume or less, or even 50% by volume or less, or 10% by volume or more, or even 20% by volume or more, taking into account the preferred proportion of the latent heat storage particles described above.

[0034] (Other additives contained in the heat storage resistor) As a third component other than the latent heat storage particles and the solid medium, additives such as sintering aids may be contained. The allowable amount of the third component in the heat storage resistor may be 10% by volume or less, further 5% by volume or less, or further 3% by volume or less.

[0035] (Shape of Heat Storage Resistor) The shape and size of the heat storage resistor can be appropriately set depending on the application. Examples of shapes include granular, cylindrical, disc-like, plate-like, and honeycomb-like.

[0036] [Method for manufacturing a heat storage resistor] One method for manufacturing a heat storage resistor of the present disclosure is the following manufacturing method: A latent heat storage particle having a core particle and a coating portion that coats at least a part of the surface of the core particle, wherein the component of the core particle is one or more selected from the group consisting of: (i) an element selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd, (ii) an alloy containing the element as a main component, (iii) a compound containing the element, (iv) an alkali metal carbonate compound, hydroxide, (nitro)nitrate, and halide, and (v) an alkaline earth metal carbonate compound, hydroxide, (nitro)nitrate, and halide, and the component of the coating portion is different from the component of the core particle and does not undergo a chemical reaction with the core particle in the operating temperature range. (I) an element, (II) an alloy containing the element, (III) one or more inorganic compounds selected from the group consisting of zinc oxide, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, and molybdenum disilicide, and (IV) a mixture thereof, wherein the inorganic compound has an electrical resistivity of 1×10 －７ ~3 x 10 ３ A method for producing a heat storage resistor, comprising: preparing latent heat storage particles having a resistance in the range of Ω cm; mixing at least the latent heat storage particles with a solid medium, and molding the mixture to obtain a molded body; and, if necessary, sintering the molded body to obtain a sintered body.

[0037] Each step will be described below.

[0038] (a) Preparation of Latent Heat Storage Particles Latent heat storage particles are prepared. There are no particular restrictions on the method for producing the latent heat storage particles. For example, the particles can be produced by the following method.

[0039] [Manufacturing of Latent Heat Storage Particles] For example, as described in Japanese Patent Application Laid-Open No. 2019-173017 filed by the present applicant, latent heat storage particles may be formed by coating core particles containing a metal / alloy-based PCM with an oxide film of the constituent elements contained in the core particles. In this process, the surface of the core particles is subjected to a chemical conversion coating treatment to form a primary coating, and then the primary coating is heat-treated to form an oxide film as a secondary coating on the surface of the core particles. The chemical conversion coating treatment may be any of a sol-gel method, anodizing treatment, an alkali-chromium hydrochloride method, a boehmite method, a chromium hydrochloride method, a phosphoric acid-chromium hydrochloride method, a zinc phosphate method, and a non-chromate chemical conversion coating treatment method. Alternatively, as described in International Application No. PCT / JP2022 / 033596 by the present applicant, latent heat storage particles may be formed by preparing core raw material particles made of a PCM containing a metal or alloy and one or more child particles that are different in component from the core particle, and colliding the core raw material particles with the child particles using an impact method in a high-velocity airflow to perform hybridization in which the child particles are fixed to the surface of the core raw material particles.

[0040] A method for manufacturing the latent heat storage particles used in this embodiment by hybridization is described below. The latent heat storage particles used in this embodiment can be manufactured by a method including preparing core material particles of a predetermined composition and child particles of a predetermined composition, and colliding the core material particles with the child particles using an impact method in a high-velocity airflow to perform hybridization, which fixes the child particles to the surfaces of the core material particles. Unlike conventional methods for manufacturing latent heat storage particles, this manufacturing method makes it easy to produce latent heat storage particles in which, for example, the main component of the core particle is different from the main component of the coating portion. Each step of this manufacturing method for latent heat storage particles is described below.

[0041] (Preparation of Raw Material Particles) As raw material particles, core material particles and child particles for forming the coating portion are prepared. The core material particles may have an average particle diameter of, for example, 10 μm or more and 200 μm or less, corresponding to the core particles of the desired latent heat storage particles. Even if the core material particles contain fine particles with a particle diameter of less than 10 μm, relatively large particles, for example, approximately 30 μm, may be obtained, for example, by the fine particles colliding with each other during hybridization. The average particle diameter may be, for example, 100 μm or less, or even 50 μm or less. The average particle diameter of the child particles is preferably 0.1 μm or more and 2 μm or less, and the ratio (average particle diameter of the child particles / average particle diameter of the core material particles) is preferably 0.001 or more and 0.2 or less. The average particle diameter of the child particles may be 1.0 μm or less, or even 0.4 μm or less. When the core material particles are not spherical, the average particle diameter is the spherical equivalent diameter. The components of the core raw material particles are the same as the components of the core particles of the latent heat storage particles, as described above for the components of the core particles of the latent heat storage particles. Furthermore, the components of the child particles are the same as the components (particularly the main components) of the coating portions of the latent heat storage particles, as described above for the components of the coating portions of the latent heat storage particles. Furthermore, if heat treatment is performed after hybridization at a temperature equal to or higher than the melting point of the components of the core raw material particles, or if melting and solidification are repeatedly performed as in the repeated tests performed in the examples, the components of the coating portions of the latent heat storage particles may be oxides of the components of the child particles, and the components of the coating portions of the latent heat storage particles may include oxides of the core raw material particles, as described above.

[0042] As an example of the blending ratio of the core material particles and the child particles to be fed into the device, the ratio of the child particles to the total of the core material particles and the child particles may be in the range of 10% by volume or more and 50% by volume or less.

[0043] A third component other than the core material particles and the child particles may include additives such as a binder and an antioxidant. The allowable amount of the third component may be 40% by volume or less when the amount of the child particles is 100% by volume.

[0044] (Hybridization of Core Raw Material Particles and Child Particles by High-Velocity Air Impact Method) In this embodiment, core raw material particles and child particles for forming a coating portion are used, and the child particles are mechanically struck against the surface of the core raw material particles by high-velocity air impact method, a dry mechanical method, to obtain latent heat storage particles in which the child particles are adhered to the surface of the core raw material particles. The "adhesion" mentioned above includes physical adhesion due to a change in the shape of the child particles, as well as adhesion due to a chemical reaction between the core raw material particles and the child particles. The degree of adhesion is not limited, as long as at least a portion of the surface of the core particle (core raw particle) is coated. The higher the coverage rate of the coating portion on the surface of the core particle, the better. As mentioned above, it is preferably 50 area% or more, more preferably 70 area% or more, even more preferably 80 area% or more, even more preferably 90 area% or more, and most preferably 100 area%.

[0045] Hereinafter, the high-velocity air current impact method used in the manufacturing method according to this embodiment will be described with reference to FIG. 1 which schematically shows a high-velocity air current impact device, but the present disclosure is not limited to this embodiment.

[0046] 1 is a schematic cross-sectional view of a high-velocity airflow impact device 100 for carrying out hybridization by the high-velocity airflow impact method. The high-velocity airflow impact device 100 is equipped with a raw material particle inlet 1, a rotor 2 that rotates at high speed, blades 3, a stator 4, a circulation circuit 5, a discharge valve 6, and a discharge port 7.

[0047] In the high-velocity airflow impact method, first, core raw material particles 8, which are a powder, and child particles 9, which are a fine powder, are supplied to the collision chamber through a sample inlet 1. Due to the rotation of the rotor 2, the core raw material particles 8 and child particles 9 in the collision chamber are scattered while rotating at high speed within the collision chamber, during which the child particles 9 collide with the surfaces of the core raw material particles 8. Some of the raw material particles enter a tube through one connection port of a circulation circuit 5 connected to the collision chamber and circulate, and are then introduced back into the collision chamber through the other connection port. This circulation circuit 5 allows the core raw material particles 8 and child particles 9 to be repeatedly subjected to a collision process. By continuing the collision caused by rotation for a certain period of time in this manner, the child particles 9 adhere to the surfaces of the core raw material particles 8, and furthermore, the child particles 9 are deformed, thereby forming latent heat storage particles 10. During the collision between the core raw material particles 8 and the child particles 9, the inlet path to the outlet 7 is closed by the discharge valve 6, but after a certain time, the obtained latent heat storage particles 10 are discharged from the outlet 7 to the outside of the device through the inlet path to the outlet 7, which is opened by moving the discharge valve 6. Although not shown, a cooling water passage may be provided to prevent the temperature inside the collision chamber from becoming too high, and the collision process may be performed while cooling by flowing cooling water. The above-mentioned high-velocity airflow impact method makes it possible to produce latent heat storage particles with combinations of core raw material particles and child particle materials that have not been obtained in the past. Furthermore, the latent heat storage particles can be obtained by a dry method, without the need for organic solvents or the like, and can be obtained in a short time, allowing for efficient and stable production of latent heat storage particles.

[0048] The peripheral speed of the rotor 2 in the above-mentioned apparatus can be, for example, in the range of 40 m / s or more and 100 m / s or less. The treatment time depends on the treatment amount, but can be, for example, in the range of 1 to 120 minutes. The treatment temperature can be, for example, in the range of room temperature to 70°C, and can further be in the range of room temperature to 50°C. The pressure and atmosphere of the collision chamber are not particularly limited. The atmosphere of the collision chamber can be, for example, an inert gas atmosphere such as an Ar atmosphere.

[0049] The latent heat storage particles obtained by the hybridization may have a porous coating formed by aggregation of child particles, and at least a portion of the coating, for example, the outermost layer of the coating, is in a particle shape. The latent heat storage particles obtained by the hybridization according to this embodiment can be used, for example, to form a heat exchange material.

[0050] The latent heat storage particles according to this embodiment do not necessarily need to be heat treated (calcined) like conventional latent heat storage particles. On the other hand, if necessary, they may be heat treated, for example, to reduce the voids contained in the porous coating portion and form a denser film as the coating portion. When heat treatment is performed, it may be performed under the following conditions.

[0051] (Heat Treatment (Caustic Treatment) Performed as Needed) The heat treatment conditions, such as temperature and atmosphere, can be set according to the components of the core raw material particles and the desired coating portion. For example, the heat treatment can be performed at a temperature equal to or higher than the melting point of the latent heat storage material, for example, heating to 700°C or higher according to the melting point of the components of the core raw material particles. In this heat treatment, the coating portion formed by the hybridization is oxidized, and for example, a stronger aluminum oxide film can be formed. The aluminum oxide film formed by the heat treatment is γ-Al at relatively low temperatures of approximately 800°C or lower. ２ O ３ It is a crystalline form of α-Al, which is considered to be chemically stable. ２ O ３ The film is obtained at a relatively high temperature of generally 880°C or higher. ２ O ３ To obtain a film, the heat treatment temperature is preferably 880° C. or higher. For example, it is preferably 880° C. or higher and 1230° C. or lower. When the core raw material particles are, for example, an Al—Si alloy, the heat treatment may be carried out at a temperature of 900° C. or higher and 1230° C. or lower.

[0052] The atmosphere for the heat treatment is not particularly limited. Examples include air atmosphere, or supplying oxygen gas to a heat treatment furnace to create an oxygen atmosphere. The temperature inside the furnace is increased using a heater, and once the temperature of the sample reaches a predetermined temperature, heat treatment (oxidation treatment) is performed for, for example, 3 to 5 hours to obtain heat-treated latent heat storage particles. Specific examples of the heat treatment method include filling a crucible with the latent heat storage particles obtained by the hybridization described above, placing the crucible on top of a thermocouple attached to the tip of an insertion rod, and setting the crucible in a heat treatment furnace equipped with a heater.

[0053] (b) Mixing and molding of the latent heat storage particles and solid medium: The latent heat storage particles and solid medium are mixed and molded to obtain a molded body. The latent heat storage particles are mixed with a solid medium such as the glass frit described above. Mixing may involve stirring for, for example, 30 minutes or more and, for example, 10 hours or less, depending on the production amount. The mixture obtained by mixing is molded to obtain a molded body such as pellets. During mixing and molding, alumina, titania, titanate, aluminate, zirconate, PVA (which can be removed by firing, etc.), etc. may be used as a binder. The proportion of the binder, etc. may be determined appropriately depending on the application. To obtain the molded body, the latent heat storage particles, etc. are mixed and molded in an extrusion molding machine to obtain pellets (molded bodies) in a granular, cylindrical, disc-shaped, plate-shaped, honeycomb-shaped, etc. shape. The heat storage resistor of the present disclosure may be the obtained molded body, and the sintering described below may not be performed.

[0054] (c) Sintering of the molded body as needed The molded body may be sintered as needed to obtain a heat storage resistor. The sintering temperature may be in the range of 600 to 800°C, for example, depending on the materials constituting the latent heat storage particles and the solid medium. The sintering atmosphere may be air, or, as needed, an Ar atmosphere or a nitrogen atmosphere.

[0055] In addition to the above steps, the above manufacturing method may include a step of processing, such as molding, after sintering depending on the intended use.

[0056] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the above-mentioned and below-mentioned aims, and all such modifications are included in the technical scope of the present invention.

[0057] 1. Preparation of latent heat storage particles (MEPCM1) First, MEPCM to be used for manufacturing the heat storage resistor was manufactured. ３ Zn-30 mass% Al alloy spherical particles (average particle size: 35.7 μm, latent heat capacity: 161 Jg) were added to 300 mL of boiling water containing 1.7 g / L of Zn-30 mass% Al alloy spherical particles (average particle size: 35.7 μm, latent heat capacity: 161 Jg －１ A Zn-Al alloy powder (Hikaru Material Industry Co., Ltd., solid-liquid phase change temperature: 444-516°C, purity: 99.0%) was added to the mixture to a concentration of 167 g / L, and the mixture was stirred at 500 rpm for 3 hours to carry out a chemical conversion treatment (boehmite treatment). The mixture was then cooled to 75°C and held for 16 hours to carry out a crystallization treatment. These treatments resulted in the formation of Al(OH) on the surface of the Zn-Al alloy particles. ３ Alternatively, a precursor on which an AlOOH coating was formed was obtained.

[0058] Five grams of the precursor was placed in an alumina boat and heated to 800°C at a rate of 10°C / min under oxygen flow, held at 800°C for 3 hours, and then cooled to room temperature at a rate of 10°C / min. This thermal oxidation treatment yielded latent heat storage particles (MEPCM1). XRD measurement of the resulting latent heat storage particles (MEPCM1) was performed under the following conditions. The results are shown in Figure 2. The latent heat storage particles (MEPCM1) were also observed using a SEM (JEOL, JSM-7001FA) and subjected to EDS analysis. The results are shown in Figures 3A to 3D. Figures 3A and 3C are micrographs at different magnifications, and Figure 3B shows the EDS analysis results for the particles in Figure 3C. Figure 3D is an enlarged photograph of the area enclosed by a square in Figure 3C. In Figure 3B, the dark gray in the spherical particles indicates the presence of zinc and oxygen, and the light gray indicates the presence of Al. (Measurement conditions) - X-ray diffraction device: XRD Rigaku MiniFlex600 - X-ray source: Cu Kα ray - Detector: High-speed one-dimensional detector D / teX Ultra2 - Wavelength (λ): 1.5418 Å

[0059] 2 and 3, the obtained latent heat storage particles (MEPCM1) maintained their spherical shape even after oxidation treatment, and the EDS analysis results in particular showed that the surface was covered with an oxide mainly composed of Zn. Furthermore, ZnO was detected in the XRD pattern. This indicated that zinc oxide was formed as the coating.

[0060] 2. Mixing and molding of latent heat storage particles and solid medium The latent heat storage particles (MEPCM1) obtained above and glass frit (average particle size: 14.6 μm, density: 3.9448 g / cm ) were mixed as a solid medium. ３ , thermal expansion coefficient: 100×10 －７ / °C, glass transition temperature: 610°C, softening point: 705°C, AGC Inc., DSG006-16) to obtain a mixed powder. ２ O ３ , B ２ O ３ and MgO, and further comprising SiO ２ , Al ２ O ３ The blending ratios of the MEPCM and other components are shown in Table 1. Next, 0.5 g of the mixed powder was cold-pressed using a die at 20 MPa for 1 minute to produce a pellet-shaped compact having a diameter of 10 mm.

[0061] 3. Sintering of the Molded Body The pellet-shaped molded body was sintered under the following conditions to obtain a heat storage resistor 1. The pellet-shaped molded body was sintered by increasing the temperature to 800°C at a rate of 5°C / min, heating at 800°C for 1 hour, and then cooling to 25°C at a rate of 5°C / min. This series of operations was carried out in the air. Photographs of the obtained heat storage resistor 1 before sintering (molded body) and after sintering (sintered body, heat storage resistor) are shown in Figure 4. From Figure 4, it can be seen that even when the proportion of MEPCM1 in heat storage resistor 1 was changed, no cracks or the like were observed after sintering, and a good molded body was produced. It was also confirmed, as shown in Figure 4, that ME25, which contains a large amount of glass frit, had a glossy surface after sintering.

[0062] 4. Evaluation of the Shape and Characteristics of Heat Storage Resistor 1 (XRD Pattern of Heat Storage Resistor 1) XRD measurement of the heat storage resistor 1 was carried out under the following conditions. The results are shown in Figure 5. From Figure 5, Al and Zn were detected in all of ME25, ME50, and M75. These elements are peaks derived from the alloy of the core particles of MEPCM1, and it can be seen that the alloy region is maintained even after sintering to produce the heat storage resistor 1. (Measurement Conditions) X-ray diffractometer: XRD Rigaku MiniFlex600 X-ray source: Cu Kα ray Detector: High-speed one-dimensional detector D / teX Ultra2 Wavelength (λ): 1.5418 Å

[0063] (SEM-EDS Measurement of Heat Storage Resistor 1) Heat storage resistors (sintered bodies) 1 of ME25, ME50, and M75 were cut, and the cut surfaces to be observed were polished with a cross-section polisher (JEOL, IB-09010CP). The polished cut surfaces were then observed with an SEM (JEOL, JSM-7001FA), and EDS analysis was performed. The results are shown in FIG. 6. The upper row of FIG. 6 is an SEM observation photograph of each heat storage resistor, and the lower row is a photograph showing the EDS analysis results of each heat storage resistor. In the EDS analysis results in the lower row of FIG. 6, for all of ME25, ME50, and M75, the darkest gray areas, as indicated by the symbol X in FIG. 6, indicate the presence of oxygen (O). In the EDS analysis results for ME25 in the lower left of Figure 6, the almost single-colored region indicated by the symbol R, which is lighter gray (medium gray) than the region indicated by the symbol X, indicates the presence of an oxide matrix phase or pores (voids) derived from the glass frit (GF), and the particulate light gray region indicated by the symbol Q, which includes white dots and has a major axis of approximately 10 to 20 μm, indicates the presence of aluminum and / or zinc. Furthermore, in ME50 in the lower right of Figure 6 and M75 in the lower right of Figure 6, the non-particulate gray region indicated by the symbol T indicates an oxide matrix phase or pores (voids) derived from the glass frit (GF), and the light gray region indicated by the symbol Q, which includes white dots and has a major axis of approximately 10 to 30 μm, indicates the presence of aluminum and / or zinc.

[0064] The EDS analysis results and the XRD pattern show that the MEPCM of the heat storage resistor of the present disclosure maintains its spherical shape even after sintering. Furthermore, even after sintering, the surface of the MEPCM1 is covered with an oxide mainly composed of Zn, and the EDS analysis results and the XRD pattern show that ZnO is formed as a shell on the surface of the MEPCM1.

[0065] (Density of Heat Storage Resistor 1) The bulk density, apparent density, and calculated density of ME25, ME50, and M75 were determined. Density of MEPCM1 (measured with a pycnometer): 4.3194 g / cm －３ Glass frit (GF) density (measured with a pycnometer): 3.9448 g / cm －３ The closed pores and open pores were calculated using the following formulas (1) and (2). The results are shown in Table 2. Open pores (%) = 100 - (Bulk density / Calculation density) x 100 - Closed pores (%) (1) Closed pores (%) = 100 - (Apparent density / Calculation density) x 100 (2)

[0066]

[0067] As shown in Table 2, ME25, which contains a relatively large amount of glass frit, has many closed pores, while ME75, which contains a relatively small amount of glass frit, has many open pores. In contrast, ME50 has the fewest total pores, and a dense sample was obtained.

[0068] (Electrical Resistivity of Heat Storage Resistor 1) The electrical resistivity of the obtained heat storage resistor 1 was determined by the four-terminal four-probe method using a resistivity meter (Loresta-GP, MCP-T610, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The results are shown in Table 3. As can be seen from Table 3, ME25 was not measurable (N / A) and was in a state of almost an insulator. ME75 had a fairly high resistivity and was in a state close to an insulator. On the other hand, ME50 had a suppressed electrical resistivity. Therefore, the current flow experiment described below was performed using this ME50. The main conductive mechanism in heat storage resistor 1 is thought to be the percolation phenomenon (the formation of a conductive network within the sample due to the arrangement of MEPCM1, which corresponds to (micro)conductive particles). ME25 had a low amount of MEPCM1, and it is thought that a conductive network was not formed. Furthermore, ME75 contained a large amount of MEPCM1 but a small amount of glass frit, resulting in low sintering ability, which is thought to have resulted in the presence of a large number of pores and reduced ability to form a conductive network. On the other hand, ME50 exhibited a good balance between the amount of MEPCM1 present and sintering ability, which is thought to have resulted in the formation of a good conductive network. While ME75 had a significantly higher electrical resistivity than ME50, there are cases where high electrical resistivity is required, and it is thought to be useful in such cases. Furthermore, from these results, it is thought that the electrical resistivity of the thermal storage resistor depends on the sintering ability of the material and the amount of MEPCM added, and it can be said that the electrical resistivity of the thermal storage resistor can be changed by adjusting the mixing ratio of MEPCM and glass frit.

[0069]

[0070] (Electrical conduction experiment of heat storage resistor 1) A cylindrical sample of ME50 having a diameter of approximately 10 mm and a height of approximately 1 cm was used as the heat storage resistor for the electrical conduction experiment. The electrical conduction experiment was conducted using an apparatus with the appearance shown in the left diagram of FIG. 7. An enlarged photograph of the area enclosed by the dashed line in the center of the left diagram of FIG. 7 is shown in the right diagram of FIG. 7. As shown in the right diagram of FIG. 7, a cylindrical sample 21, which is a heat storage resistor, was sandwiched between copper plates 23 coated with silver paste and electrical conduction was conducted. The temperature of the sample during the experiment was measured with a thermocouple 25, as shown in the right diagram of FIG. 7.

[0071] Before the current experiment, a vacuum was drawn for five minutes and then argon gas was introduced, which was repeated five times. The current experiment was then conducted while the vacuum pump was running. A current was applied in advance to investigate the output power required to raise the temperature to 590°C, which is sufficient to melt the PCM inside the sample. The current application conditions (voltage, current) and sample temperature are shown in Figure 8A). In Figure 8A, a current of 19 W was applied to the sample. After the sample temperature reached 590°C, the current was held for one minute before being turned off. When the sample temperature had dropped to 150°C, the current was turned on again. This procedure was repeated a total of 10 times.

[0072] The temperature history during cooling from 590°C for the first and tenth current cycles is shown in Figure 8B) and Figure 8C), respectively. From Figure 8B) and Figure 8C), it was confirmed that temperature stagnation occurred around 480°C and around 230°C when the heat storage resistor was cooled, in both the first and tenth current cycles. The temperature around 480°C is due to a solid-liquid (solid-liquid phase) change of the PCM, and the temperature around 230°C is due to a solid-solid (solid-solid phase) change. From these results in Figure 8A) to C), it was possible to confirm the heating and heat storage due to the current flow in the heat storage resistor of the present disclosure.

[0073] (DSC curve of heat storage resistor 1) A differential scanning calorimeter (TGA-DSC, manufactured by Mettler Toledo, TGA-DSC-3) was used, and an alumina pan was used. Under an air atmosphere, the temperature was decreased from 800 ° C. to 400 ° C. at a rate of 5 ° C. / min (K / min), and differential scanning calorimetry was performed during temperature decrease (heat dissipation side) to obtain a DSC curve. The results are shown in FIG. 9. In FIG. 9, line c) shows the results from the first current cycle (as-prepared), and line d) shows the results from the 10th current cycle. From FIG. 9, peaks due to solid-solid and solid-liquid changes of the PCM were confirmed in the DSC curve near about 230 ° C. and about 480 ° C., respectively. Furthermore, no decrease in latent heat was observed even after 10 current cycles.

[0074] From the results of this example, according to the present disclosure, the presence of a ZnO shell on the surface of the MEPCM 1 resulted in a heat storage resistor 1 that functions both as a resistor that generates thermal energy when current is applied and as a heat storage body that can store the thermal energy. The heat storage resistor of the present disclosure is a resistor that becomes a heat generator when current is applied, and also functions as a heat storage body that can store the generated heat. Because it is a resistor that becomes a heating element when current is applied, and also serves as a heat storage body that can store the generated heat, it can be used in place of the heater and heat storage tank in conventional electric heat exchange systems, reducing the number of heat transfers. As a result, it is expected that energy loss associated with heat transfer can be effectively reduced. Furthermore, according to the present disclosure, for example, a heat storage resistor that can store high-temperature heat can be provided by including latent heat storage particles having core particles with a relatively high melting point of 430 to 510°C, as in this example. Furthermore, while conventional systems require large heaters and heat storage tanks to generate and store large amounts of energy, the heat storage resistor of the present disclosure can function as both a heater and a heat storage tank, thereby contributing to the miniaturization of equipment.

[0075] 5. Preparation of Latent Heat Storage Particles (MEPCM2, 3, 4, 5) (Preparation of MEPCM2) 333 g / L of Al-12 mass% Si alloy particles (core particles A) were added to boiling water containing 3.3 g / L of aluminum hydroxide (manufactured by Kojundo Chemical Laboratory) suspended in water, and the mixture was held for 3 hours with stirring. The mixture was then held at 75°C for 16 hours with stirring to obtain a precursor sample. The precursor sample was heated in a heat treatment furnace in an air atmosphere from 25°C to 1200°C at a rate of 10°C / min and held at 1200°C for 3 hours. The heat treatment furnace was then cooled, and the core particles were found to be Al-12 mass% Si alloy particles and the shell (coating portion) was found to be α-Al. ２ O ３ MEPCM2 was obtained.

[0076] (Preparation of MEPCM3) 333 g / L of Al particles (core particles B) were added to boiling water and held for 3 hours while stirring to obtain a precursor sample. The precursor sample was heated in a heat treatment furnace in an air atmosphere from 25°C to 1200°C at a rate of 10°C / min and held at 1200°C for 3 hours. The heat treatment furnace was then cooled to obtain MEPCM3. The core particles were Al particles and the shell (coating portion) was α-Al. ２ O３ As a result, latent heat storage particles (MEPCM3) of the formula (1) were obtained.

[0077] (Preparation of MEPCM4) Al-29.5 mass% Cu-6 mass% Si alloy particles (core particles C) and α-Al ２ O ３ The particles (manufactured by Kojundo Chemical Laboratory) were mixed by hand in a ratio of 80% by volume:20% by volume to obtain a mixed powder. The obtained mixed powder was treated using hybridization at a peripheral speed of 100 m / s for a treatment time of 5 minutes to form α-Al on the surfaces of the alloy particles. ２ O ３ A sample with a coating was obtained. The sample was then heated in a heat treatment furnace in an oxygen atmosphere from 25°C to 1000°C at a rate of 10°C / min and held at 1000°C for 3 hours. The heat treatment furnace was then cooled, and the core particles were found to be Al-29.5 mass% Cu-6 mass% Si alloy particles, and the shell (coating portion) was found to be α-Al. ２ O ３ As a result, latent heat storage particles (MEPCM4) of

[0078] (Preparation of MEPCM5) Cu-12.8 mass% Si-20 mass% Al alloy particles (core particles D) and α-Al ２ O ３ The particles (manufactured by Kojundo Chemical Laboratory) were mixed by hand in a ratio of 80% by volume:20% by volume to obtain a mixed powder. The obtained mixed powder was treated using hybridization at a peripheral speed of 50 m / s for a treatment time of 3 minutes to form α-Al on the surfaces of the alloy particles. ２ O ３ A sample with a coating was obtained. The sample was then heated in a heat treatment furnace in an oxygen atmosphere from 25°C to 1000°C at a rate of 10°C / min and held at 1000°C for 3 hours. The heat treatment furnace was then cooled, and the core particles were found to be Cu-12.8 mass% Si-20 mass% Al alloy particles, and the shell (coating portion) was found to be α-Al. ２ O ３ As a result, latent heat storage particles (MEPCM5) of

[0079] 6. Preparation of Heat Storage Resistors 2, 3, 4, 5, and 6 (Preparation of Heat Storage Resistor 2) The latent heat storage particles (MEPCM2) obtained above and ZnO particles (manufactured by Kojundo Chemical Laboratory) were mixed by hand to a ratio of 80% by volume:20% by volume to obtain a mixed powder. The obtained mixed powder was pressed at 20 MPa for 1 minute at 25°C to obtain a molded body. The molded body was heated from 25°C to 800°C at a rate of 5°C / min and held for 1 hour. It was then cooled to 25°C at a rate of 10°C / min to obtain heat storage resistor 2.

[0080] (Preparation of Heat Storage Resistor 3) The above-obtained latent heat storage particles (MEPCM2) and expanded graphite particles (EC1500, manufactured by Itoh Graphite Co., Ltd.) were mixed by hand at a ratio of 50% by volume:50% by volume to obtain a mixed powder. The obtained mixed powder was pressed at 20 MPa for 1 minute at 25°C to obtain a molded body as the heat storage resistor 3.

[0081] (Preparation of Heat Storage Resistor 4) The latent heat storage particles (MEPCM3) obtained above and expanded graphite particles (EC1500, manufactured by Itoh Graphite Co., Ltd.) were mixed by hand at a ratio of 50% by volume:50% by volume to obtain a mixed powder. The obtained mixed powder was pressed at 20 MPa for 1 minute at 25°C to obtain a molded body as a heat storage resistor 4.

[0082] The latent heat storage particles (MEPCM4) obtained above and expanded graphite particles (EC1500, manufactured by Itoh Graphite Co., Ltd.) were mixed by hand at a ratio of 50% by volume:50% by volume to obtain a mixed powder. The mixed powder obtained was pressed at 20 MPa for 1 minute at 25°C to obtain a heat storage resistor 5 as a molded body.

[0083] (Preparation of Heat Storage Resistor 6) The latent heat storage particles (MEPCM5) obtained above and expanded graphite particles (EC1500, manufactured by Itoh Graphite Co., Ltd.) were mixed by hand at a ratio of 50% by volume:50% by volume to obtain a mixed powder. The obtained mixed powder was pressed at 20 MPa for 1 minute at 25°C to obtain a molded body as a heat storage resistor 6.

[0084] 7. Evaluation of the characteristics of the heat storage resistors 2 to 6 (Electrical resistivity of the heat storage resistors 2 to 6) The electrical resistivity ρ (volume resistivity) of the obtained heat storage resistors 2 to 6 was calculated by measuring the height (L [cm]) and diameter of the cylindrical heat storage resistor with a vernier caliper and calculating the cross-sectional area (S [cm ２]) was calculated, and the values ​​of voltage V [V] and current I [A] applied in the current application experiments, shown in Figures 10 to 14, were used to calculate the resistance from the following general formula (3). The results are shown in Table 4. From the results in Table 4, it can be seen that the solid medium of all the heat storage resistors acts as a resistor, and exhibits an electrical resistivity appropriate for generating heat when current is applied. ρ = (V / I) × (S / L) (3) Where, ρ: electrical resistivity [Ω cm], V: voltage [V], I: current value [A], S: area of ​​the bottom surface of the heat storage resistor [cm ２ ], L: height of heat storage resistor [cm]

[0085]

[0086] (Experiment on energizing heat storage resistors 2 to 6) An experiment on energizing the obtained heat storage resistors 2 to 6 was carried out using the device shown in the left diagram of Fig. 7, similar to the experiment on energizing the heat storage resistor 1 described above. The resulting energizing conditions (voltage, current) and sample temperatures are shown in Figs. 10 to 14, respectively. From these results, it was possible to confirm heating and heat storage by energizing the heat storage resistor of the present disclosure.

[0087] This application claims priority from Japanese Patent Application No. 2024-010492, which is incorporated herein by reference.

[0088] REFERENCE SIGNS LIST 1 Raw material particle inlet 2 Rotor 3 Blade 4 Stator 5 Circulation circuit 6 Discharge valve 7 Discharge port 8 Core raw material particle 9 Child particle 21 Cylindrical sample 23 Copper plate 25 Thermocouple 10 Latent heat storage particle 100 High-speed airflow impact device

Claims

1. A heat storage resistor including latent heat storage particles and a solid medium, having an electrical resistivity within the range of 1×10 －７ to 3×10 ３ Ω·cm, wherein the latent heat storage particles have a core particle and a coating portion covering at least a part of the surface of the core particle, and the component of the core particle is one or more selected from the group consisting of (i) elements selected from the group consisting of Al, Mg, Si, Ti, Fe, Ni, Cu, Zn, Sn, Sb, Ga, In, Bi, Pb, and Cd, (ii) alloys having the element as a main component, (iii) compounds containing the element, (iv) carbonate compounds, hydroxides, (nitrite) nitrides, and halides of alkali metals, and (v) carbonate compounds, hydroxides, (nitrite) nitrides, and halides of alkaline earth metals, having a melting point of 100°C or higher, and the component of the coating portion is one or more selected from the group consisting of (I) elements, (II) alloys containing the element, (III) one or more inorganic compounds selected from the group consisting of zinc oxide, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, and molybdenum disilicide, and (IV) mixtures thereof, which do not cause a chemical reaction with the core particle in the temperature range of the operating temperature, different from the component of the core particle, and having an electrical resistivity within the range of 1×10 －７ to 3×10 ３ Ω·cm, the heat storage resistor.

2. The heat storage resistor according to claim 1, wherein the alloy component of the coating portion is one or more of a Kanthal alloy and a nichrome alloy.

3. The heat storage resistor according to claim 1 or 2, wherein the proportion of the latent heat storage particles in the heat storage resistor is 10 to 90% by volume.

4. The heat storage resistor according to claim 1 or 2, wherein the average particle diameter of the core particles is 10 μm or more and 200 μm or less.

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