Latent heat storage body and method for manufacturing latent heat storage body

Abstract

To provide a latent heat storage body capable of improving stability, and a method for manufacturing the latent heat storage body.SOLUTION: A latent heat storage body includes a ceramic part formed of a polycrystalline material and including a closed space formed therein, and a metal part provided inside the closed space and including aluminum.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a latent heat storage material and a method for manufacturing a latent heat storage material. [Background technology]

[0002] Conventionally, a latent heat storage medium has been proposed in which aluminum is used as a phase change material (PCM), and the PCM is surrounded by a laminate of carbon and silicon carbide, or a protective layer of alumina and copper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6967790 [Patent Document 2] Patent No. 6057184 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-111825 [Non-patent literature]

[0004] [Non-Patent Document 1] Qinglin Li et al., "Preparation of a new capsule phase change material for high temperature thermal energy storage", Journal of Alloys and Compounds, Volume 868, 2021, 159179. [Non-patent document 2] JW McMurray et al., "Ceramic encapsulated metal phase change material for high temperature thermal energy storage", Applied Thermal Engineering, Volume 170, 2020, 115003 Summary of the Invention [Problem to be solved by the invention]

[0005] Latent heat storage materials are used at high temperatures. In conventional latent heat storage materials in which the PCM is a laminate of carbon and silicon carbide or surrounded by a protective layer of alumina and copper, the protective layer deteriorates during use. For example, when an oxidizing gas such as air is used as a heat transfer medium, the protective layer oxidizes. Oxidation is particularly likely to progress when impurities such as inorganic salts are present in the usage environment. The deterioration of the protective layer may shorten the life of the latent heat storage material.

[0006] An object of the present disclosure is to provide a latent heat storage material and a method for manufacturing a latent heat storage material that can improve stability. [Means for solving the problem]

[0007] According to one embodiment of the present disclosure, there is provided a latent heat storage medium having a ceramic part made of a polycrystalline body in which a closed space is formed, and a metal part containing aluminum that is provided within the closed space. [Effects of the Invention]

[0008] According to the disclosed technology, stability can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a latent heat storage material according to a first embodiment. FIG. [Figure 2] 2A to 2C are diagrams illustrating a method for manufacturing a latent heat storage material according to the first embodiment. [Figure 3] FIG. 6 is a diagram illustrating a latent heat storage material according to a second embodiment. [Figure 4] FIG. 10 is a diagram illustrating a latent heat storage material according to a third embodiment. [Figure 5] 10A to 10C are diagrams illustrating a method for manufacturing a latent heat storage material according to a third embodiment. [Figure 6] 10A to 10C are diagrams illustrating a method for manufacturing a latent heat storage material according to a second embodiment. [Figure 7] FIG. 10 is a perspective view illustrating a latent heat storage material according to a fourth embodiment. [Figure 8] FIG. 10 is a perspective view illustrating a latent heat storage material according to a fifth embodiment. [Figure 9] 10A and 10B are cross-sectional views showing examples of arrangements of through holes and metal parts in the fifth embodiment. [Figure 10] FIG. 10 is a diagram illustrating a latent heat storage material according to a sixth embodiment. [Figure 11] FIG. 10 is a perspective view showing a metal part included in a latent heat storage material according to a sixth embodiment. [Figure 12] FIG. 13 is a diagram illustrating a latent heat storage material according to a seventh embodiment. [Figure 13] FIG. 13 is a perspective view showing a metal part included in a latent heat storage material according to a seventh embodiment. [Figure 14] FIG. 13 is a cross-sectional view illustrating a latent heat storage medium according to an eighth embodiment. [Figure 15] FIG. 20 is a cross-sectional view illustrating a latent heat storage material according to a first modified example of the eighth embodiment. [Figure 16] FIG. 20 is a cross-sectional view illustrating a latent heat storage material according to a second modified example of the eighth embodiment. [Figure 17] FIG. 13 is a diagram illustrating a latent heat storage material according to a ninth embodiment. [Figure 18] FIG. 13 is a diagram illustrating a method of using the latent heat storage material according to the ninth embodiment. [Figure 19] FIG. 20 is a perspective view illustrating a latent heat storage material according to a tenth embodiment. [Figure 20] FIG. 20 is a diagram illustrating a method of using the latent heat storage material according to the tenth embodiment. [Figure 21] FIG. 20 is a perspective cross-sectional view illustrating a latent heat storage material according to an eleventh embodiment. [Figure 22] FIG. 22 is a cross-sectional view illustrating a latent heat storage medium according to a twelfth embodiment. [Figure 23] FIG. 23 is a cross-sectional view illustrating a latent heat storage material according to a first modified example of the twelfth embodiment. [Figure 24] FIG. 23 is a cross-sectional view illustrating a latent heat storage material according to a second modified example of the twelfth embodiment. [Figure 25] FIG. 22 is a cross-sectional view illustrating a latent heat storage medium according to a thirteenth embodiment. [Figure 26] FIG. 23 is a diagram illustrating a method of using the latent heat storage material according to the thirteenth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations may be omitted.

[0011] (First embodiment) A first embodiment will be described. The first embodiment relates to a latent heat storage material. Fig. 1 is a diagram illustrating a latent heat storage material according to the first embodiment. Fig. 1(a) is a perspective view, and Fig. 1(b) is a cross-sectional view.

[0012] As shown in FIGS. 1(a) and 1(b), the latent heat storage material 1 according to the first embodiment has a ceramic part 110 made of a polycrystalline body and a metal part 120.

[0013] A closed space 111 is formed in the ceramic part 110. The ceramic part 110 and the closed space 111 are shaped like a rectangular parallelepiped. The ceramic part 110 is, for example, formed as an integral unit. For example, the ceramic part 110 does not have a joint that connects to the closed space 111. The ceramic part 110 contains, for example, aluminum oxide at a ratio of 96% by mass or more. In other words, the ceramic part 110 may be made of aluminum oxide with a purity of 96% by mass or more.

[0014] The metal part 120 is provided in the closed space 111. In other words, the metal part 120 is sealed in the ceramic part 110. It can also be said that the metal part 120 is airtightly covered by the ceramic part 110, which is a continuous body. The metal part 120 contains aluminum. For example, the main component of the metal part 120 is aluminum. The metal part 120 contains aluminum at a rate of, for example, 99% by mass or more. In other words, the metal part 120 may be made of aluminum with a purity of 99% by mass or more.

[0015] The volume of the closed space 111 is preferably larger than the volume of the metal part 120. This is because, as described below, when the latent heat storage material 1 is used, the metal part 120 undergoes a phase change from solid to liquid, and the metal part 120 expands during this phase change. Furthermore, if the metal part 120 is mainly composed of aluminum, the metal part 120 expands by approximately 14% by volume during the phase change. Therefore, at 25°C, the volume of the closed space 111 is preferably 114% or more of the volume of the metal part 120. Note that if the volume of the closed space 111 is excessively large compared to the volume of the metal part 120, not only will the ceramic part 110 become unnecessarily large, but the thermal resistance between the ceramic part 110 and the metal part 120 will also increase. Therefore, at 25°C, the volume of the closed space 111 is preferably 120% or less of the volume of the metal part 120. When the main component of the metal part 120 is aluminum, the metal part 120 thermally expands at a rate of approximately 23 ppm / °C as its temperature rises from 25°C to its melting point. With this level of thermal expansion, the ceramic part 110 can withstand the thermal stress.

[0016] When the volume of the closed space 111 is larger than the volume of the metal part 120, a gap exists between the surface of the metal part 120 and the inner surface of the closed space 111. The gap between the surface of the metal part 120 and the inner surface of the closed space 111 may exist in only one location, or in multiple locations.

[0017] The melting point of aluminum is 660°C. When the metal part 120 is primarily composed of aluminum, a phase change between solid and liquid occurs at approximately 660°C. At this temperature, the ceramic part 110, which is made of polycrystalline material, is chemically stable. Therefore, whether the metal part 120 is solid or liquid, the ceramic part 110 can confine the metal part 120 within the closed space 111. Furthermore, even when used at high temperatures, the ceramic part 110 is less likely to undergo chemical changes such as oxidation.

[0018] According to the latent heat storage material 1, the metal part 120 functions as a phase change material (PCM), so high thermal conductivity can be obtained. Furthermore, even when used at high temperatures, the ceramic part 110 is less likely to be altered, such as oxidized. This improves stability. Therefore, an oxidizing material such as air can be used as a heat transfer medium, widening the range of heat transfer medium options.

[0019] Furthermore, the surface of the latent heat storage material 1 can be easily cleaned. For example, when the heat transfer medium is exhaust gas from a combustion furnace containing unburned components, the heat transfer medium may contain substances such as soot that tend to adhere to the latent heat storage material 1. The adhesion of such substances may lead to a decrease in thermal conductivity and an increase in flow resistance. In contrast, with the latent heat storage material 1, the adhered substances can be easily removed by high-temperature treatment in the atmosphere, for example. If the adhered substances are non-organic, they can also be removed by acid washing, for example.

[0020] Next, a method for manufacturing the latent heat storage material 1 according to the first embodiment will be described. Fig. 2 is a diagram illustrating the method for manufacturing the latent heat storage material 1 according to the first embodiment. Fig. 2(a) is a perspective view, and Fig. 2(b) is a cross-sectional view.

[0021] First, as shown in Figures 2(a) and 2(b), a composite 1A is prepared that has an unsintered ceramic portion 130 and a metal portion 140. The metal portion 140 is covered by the ceramic portion 130. Later, the ceramic portion 130 becomes the ceramic portion 110, and the metal portion 140 becomes the metal portion 120.

[0022] The ceramic portion 130 is, for example, a green sheet laminate, a slip-cast body, a gel-cast body, or a cold isostatic pressing (CIP) compact formed after preforming granulated powder, containing the material of the ceramic portion 110. The ceramic portion 130 contains, for example, aluminum oxide at a ratio of 96% by mass or more. The ceramic portion 130 may further contain a sintering aid or the like. Examples of sintering aids include silicon, magnesium, and calcium. The ceramic portion 130 more preferably contains aluminum oxide at a ratio of 99% by mass or more. The particle size of the ceramic grains contained in the ceramic portion 130 is preferably 1 μm or less, more preferably 0.3 μm or less.

[0023] The metal part 140 is, for example, a wire material, a pillar material, a paste, a slip-cast body, a gel-cast body, or a CIP molded body obtained by preforming granulated powder, each of which contains aluminum. The metal part 140 contains, for example, 99% by mass or more of aluminum.

[0024] A closed space 131 is formed in the ceramic part 130, and the metal part 260 is provided inside the closed space 131. The volume of the closed space 131 is larger than the volume of the metal part 140, and a gap exists between the surface of the metal part 140 and the inner surface of the closed space 131.

[0025] Next, the ceramic portion 130 and the metal portion 140 are simultaneously fired. As a result, the ceramic portion 110 is formed from the ceramic portion 130, and the metal portion 120 is formed from the metal portion 140 (see FIGS. 1(a) and 1(b)). At this time, the porous ceramic portion 130 becomes densified, and the relative density of the polycrystalline ceramic portion 110 becomes approximately 95% to 99%. On the other hand, the metal portion 140 hardly becomes densified, and the relative density of the metal portion 120 becomes approximately 100%. Therefore, it is preferable to determine the relative densities of the ceramic portion 130 and the metal portion 140 by taking into consideration the difference in relative density change due to firing. Note that in this disclosure, even if the metal portion does not undergo any changes in components or properties other than a phase change during firing of the ceramic portion, the metal portion is fired, and these may be simultaneously fired. Furthermore, relative density refers to the density relative to the density in a solid bulk state. In other words, relative density refers to the ratio of the density of a comparison object to the density in a state without any voids or defects.

[0026] The co-firing temperature is, for example, 400°C to 900°C higher than the melting point of the metal part 140. The temperature rise rate during co-firing is, for example, 5°C / min to 15°C / min. The co-firing atmosphere may be, for example, a reducing atmosphere containing a reducing gas such as hydrogen, a non-oxidizing atmosphere containing a non-oxidizing gas such as nitrogen, or an oxidizing atmosphere containing an oxidizing gas such as air. Note that when co-firing is performed in an oxidizing atmosphere, an oxide film that was present on the surface of the metal material that constitutes the metal part 140 may remain in the metal part 120. Even in this case, the oxide film may remain in the metal part 120 because sufficient heat capacity associated with the phase change can be obtained.

[0027] In this manner, the latent heat storage material 1 according to the first embodiment can be manufactured.

[0028] When the ceramic part 130 contains aluminum oxide in a proportion of 96% by mass or more (hereinafter sometimes referred to as "having a specified composition"), it is particularly easy to suppress the reaction between the material of the ceramic part 130 and the material of the metal part 140 when the ceramic part 130 and the metal part 140 are co-fired.

[0029] Furthermore, when the ceramic portion 130 has a predetermined composition, it is particularly easy to prevent the molten metal portion 140 from penetrating into the ceramic portion 130. For example, the melting point of the metal portion 140 is lower than the temperature at which the ceramic portion 130 densifies, and the metal portion 140 melts before the ceramic portion 130 densifies. If the molten metal portion 140 penetrates the ceramic portion 130 before densification, the densification of the ceramic portion 130 may be hindered, preventing the formation of the closed space 111, or the metal portion 140 may flow out of the ceramic portion 130. When the ceramic portion 130 has a predetermined composition, it is particularly easy to prevent such phenomena from occurring.

[0030] Furthermore, when the ceramic portion 130 has a predetermined composition, even if a portion of the molten metal portion 140 evaporates, it is particularly easy to prevent the evaporated components from penetrating into the ceramic portion 130. When the metal portion 140 melts, a portion of it evaporates within the closed space 131. If the evaporated components penetrate into the ceramic portion 130 before densification, the densification of the ceramic portion 130 may be hindered, preventing the closed space 111 from being formed, or the evaporated components may diffuse outside the ceramic portion 130. When the ceramic portion 130 has a predetermined composition, it is particularly easy to prevent such phenomena from occurring.

[0031] In order to make the volume of the closed space 111 larger than that of the metal part 120, for example, if the metal part 140 is a paste, slip-cast body, gel-cast body, or CIP molded body, it is preferable to adjust the relative density of the metal part 140 to be low before firing. Furthermore, in order to make the volume of the closed space 111 larger than that of the metal part 120, for example, if the metal part 140 is a wire or column material, it is preferable to provide an organic component that disappears during firing on the surface of the wire or column material. Suitable examples of such organic components include ethyl cellulose, polyvinyl alcohol, polyvinyl butyral, and polymethacrylate. The temperature at which the densification of the ceramic part 130 occurs is higher than the temperature at which the organic component disappears and the melting point of the metal part 140, so the densification of the ceramic part 130 is not inhibited.

[0032] (Second embodiment) A second embodiment will be described. The second embodiment relates to a latent heat storage material. Fig. 3 is a diagram illustrating a latent heat storage material according to the second embodiment. Fig. 3(a) is a perspective view, and Fig. 3(b) is a cross-sectional view.

[0033] As shown in FIGS. 3(a) and 3(b), the latent heat storage material 2 according to the second embodiment has a ceramic part 210 made of a polycrystalline body and a metal part 220.

[0034] A closed space 211 is formed in the ceramic part 210. The ceramic part 210 and the closed space 211 are cylindrical in shape. The ceramic part 210 is, for example, formed integrally. For example, the ceramic part 210 does not have a joint portion connecting to the closed space 211. The ceramic part 210 is made of the same material as the ceramic part 110.

[0035] The metal part 220 is provided in the closed space 211. In other words, the metal part 220 is sealed in the ceramic part 210. It can also be said that the metal part 220 is airtightly covered by the ceramic part 210, which is a continuous body. The metal part 220 is made of the same material as the metal part 120.

[0036] The volume of the closed space 211 is preferably larger than the volume of the metal part 220. When the volume of the closed space 211 is larger than the volume of the metal part 220, a gap exists between the surface of the metal part 220 and the inner surface of the closed space 211, although this is omitted in Fig. 3(a). The gap between the surface of the metal part 220 and the inner surface of the closed space 211 may exist in only one location, or may exist in multiple locations.

[0037] Other configurations are the same as those of Embodiment 1. Furthermore, the latent heat storage material 2 according to the second embodiment can be manufactured by the same method as that of the first embodiment, except for the shape.

[0038] The second embodiment can also provide the same effects as the first embodiment. Furthermore, since external stress to the ceramic part 210 is easily dispersed, higher durability can be obtained.

[0039] The latent heat storage material may have a spherical or prismatic shape.

[0040] (Third embodiment) A third embodiment will be described. The third embodiment relates to a latent heat storage material. Fig. 4 is a diagram illustrating a latent heat storage material according to the third embodiment. Fig. 4(a) is a perspective view, and Fig. 4(b) is a cross-sectional view.

[0041] The latent heat storage material 3 according to the third embodiment has a ceramic part 310 made of a polycrystalline body and a plurality of metal parts 320, as shown in FIGS. 4(a) and 4(b).

[0042] A plurality of closed spaces 311 are formed in the ceramic part 310. The ceramic part 310 and the closed spaces 311 are shaped like a rectangular parallelepiped. The ceramic part 310 is, for example, formed as an integral unit. For example, the ceramic part 310 does not have any joints connecting to the closed spaces 311. The ceramic part 310 is made of the same material as the ceramic part 110. The closed spaces 311 are arranged at equal intervals in two directions perpendicular to each other within a plane parallel to a pair of parallel planes of the ceramic part 310.

[0043] Each metal part 320 is provided in the closed space 311. In other words, the metal part 320 is sealed in the ceramic part 310. It can also be said that the metal part 320 is airtightly covered by the ceramic part 310, which is a continuous body. The metal part 320 is made of the same material as the metal part 120.

[0044] The volume of the closed space 311 is preferably larger than the volume of the metal part 320. When the volume of the closed space 311 is larger than the volume of the metal part 320, a gap exists between the surface of the metal part 320 and the inner surface of the closed space 311, although this is not shown in Fig. 4(a). The gap between the surface of the metal part 320 and the inner surface of the closed space 311 may exist in only one location, or in multiple locations.

[0045] The other configurations are the same as those in the first embodiment.

[0046] Next, a method for manufacturing the latent heat storage material 3 according to the third embodiment will be described. Fig. 5 is a diagram illustrating a method for manufacturing the latent heat storage material 3 according to the third embodiment.

[0047] First, as shown in FIG. 5(a), an unsintered ceramic part 350A is prepared, in which a plurality of cavities 351 that will become the closed spaces 311 are formed. The ceramic part 350A is, for example, a laminate of green sheets. The ceramic part 350A may be formed by injection molding or the like. Later, the ceramic part 350A will become a part of the ceramic part 310.

[0048] 5(b), a metal portion 360 is provided in each cavity 351. Later, the metal portion 360 becomes the metal portion 320. The metal portion 360 is, for example, a paste, a bead, a wound wire, or a sheet.

[0049] 5(b), a sheet-like ceramic portion 350B is provided on the ceramic portion 350A so as to close the open end of the cavity 351. The ceramic portion 350B will later become a part of the ceramic portion 310.

[0050] In this way, a composite body 3A having unsintered ceramic portions 350A and 350B and a metal portion 360 is obtained, as shown in FIG. 5(c).

[0051] Next, the ceramic portions 350A and 350B and the metal portion 360 are simultaneously fired. As a result, the ceramic portion 310 is formed from the ceramic portions 350A and 350B, and the metal portion 320 is formed from the metal portion 360 (see FIGS. 4(a) and 4(b)).

[0052] In this manner, the latent heat storage material 3 according to the third embodiment can be manufactured.

[0053] The third embodiment can also provide the same effects as the first embodiment.

[0054] Before firing the composite 3A, the composite 3A may be divided into individual metal parts 360. In this case, the latent heat storage material 1 according to the first embodiment can be obtained.

[0055] The latent heat storage material 2 according to the second embodiment can also be obtained by a similar method. Fig. 6 is a diagram showing a method for producing the latent heat storage material 2 according to the second embodiment.

[0056] First, as shown in FIG. 6(a), an unfired ceramic part 250A having a plurality of cavities 251 that will become the closed spaces 211 formed therein is prepared.

[0057] Next, as shown in FIG. 6(b), a metal portion 260 is provided in each cavity 251.

[0058] Next, as shown in FIG. 6(c), a sheet-like ceramic part 250B is provided on the ceramic part 250A so as to close the open end of the cavity 251, thereby obtaining a composite body 2A.

[0059] Next, the composite body 2A is divided into individual metal portions 260. Then, the ceramic portions 250A and 250B and the metal portions 260 are fired simultaneously.

[0060] By using such a method, the latent heat storage material 2 according to the second embodiment can also be manufactured.

[0061] The composite for producing the latent heat storage medium may be produced by a method such as dip coating of a ceramic slurry.

[0062] (Fourth embodiment) A fourth embodiment will be described. The fourth embodiment relates to a latent heat storage material. Fig. 7 is a perspective view illustrating an example of a latent heat storage material according to the fourth embodiment.

[0063] As shown in FIG. 7, the latent heat storage material 4 according to the fourth embodiment has a ceramic part 410 made of a polycrystalline material and a metal part 420.

[0064] The ceramic part 410 has a cylindrical shape with a through hole 414. The ceramic part 410 may have a square cylindrical shape with a through hole 414. The ceramic part 410 has a cylindrical shape with an inner wall surface 412 and an outer wall surface 413. A closed space 411 is formed in the ceramic part 410. The closed space 411 has a spiral shape along the inner wall surface 412 and the outer wall surface 413. The ceramic part 410 is, for example, formed integrally. For example, the ceramic part 410 does not have a joint connecting to the closed space 411. The ceramic part 410 is made of the same material as the ceramic part 110.

[0065] The metal part 420 is provided in the closed space 411. In other words, the metal part 420 is sealed in the ceramic part 410. It can also be said that the metal part 420 is airtightly covered by the ceramic part 410, which is a continuous body. The metal part 420 has a spiral shape along the inner wall surface 412 and the outer wall surface 413. The metal part 420 is made of the same material as the metal part 120.

[0066] The volume of the closed space 411 is preferably larger than the volume of the metal part 420. When the volume of the closed space 411 is larger than the volume of the metal part 420, a gap exists between the surface of the metal part 420 and the inner surface of the closed space 411, although this is not shown in Fig. 7. The gap between the surface of the metal part 420 and the inner surface of the closed space 411 may exist in only one location, or in multiple locations.

[0067] Other configurations are the same as those of Embodiment 1. Furthermore, the latent heat storage material 4 according to the fourth embodiment can be manufactured by the same method as that of Embodiment 1, except for the shape.

[0068] The fourth embodiment can also achieve the same effects as the first embodiment. Furthermore, the through holes 414 can be used as a flow path for the heat medium. In this case, the flow rate and flow velocity of the heat medium can be easily stabilized.

[0069] (Fifth embodiment) A fifth embodiment will be described. The fifth embodiment relates to a latent heat storage material. Fig. 8 is a perspective view illustrating an example of a latent heat storage material according to the fifth embodiment.

[0070] As shown in FIG. 8, the latent heat storage material 5 according to the fifth embodiment has a ceramic part 510 made of a polycrystalline material and a metal part 520.

[0071] A plurality of closed spaces 511 are formed in the ceramic part 510. The ceramic part 510 has a substantially rectangular parallelepiped shape. A plurality of through holes 514 extending in a first direction are formed in the ceramic part 510. The first direction is perpendicular to a pair of parallel planes of the ceramic part 510. The closed spaces 511 are cylindrical in shape. The plurality of closed spaces 511 extend in the first direction. The closed spaces 511 are provided near the through holes 514. The ceramic part 510 is, for example, integrally formed. For example, the ceramic part 510 does not have any joints connecting to the closed spaces 511. The ceramic part 510 is made of the same material as the ceramic part 110.

[0072] The metal parts 520 are provided one by one in the closed space 511. In other words, the metal parts 520 are sealed in the ceramic part 510. It can also be said that the metal parts 520 are airtightly covered by the ceramic part 510, which is a continuous body. The metal parts 520 have a columnar shape parallel to the first direction. The metal parts 520 are made of the same material as the metal part 120.

[0073] The volume of closed space 511 is preferably larger than the volume of metal part 520. When the volume of closed space 511 is larger than the volume of metal part 520, a gap exists between the surface of metal part 520 and the inner surface of closed space 511, although this is not shown in Fig. 8. The gap between the surface of metal part 520 and the inner surface of closed space 511 may exist in only one location, or in multiple locations.

[0074] Other configurations are the same as those of Embodiment 1. Furthermore, the latent heat storage material 5 according to the fifth embodiment can be manufactured by the same method as that of Embodiment 1, except for the shape.

[0075] The fifth embodiment can also achieve the same effects as the first embodiment. Furthermore, the plurality of through holes 514 can be used as a flow path for the heat medium. In this case, it is easy to stabilize the flow rate and flow velocity of the heat medium.

[0076] Here, a description will be given of an example of the arrangement of the through holes 514 and the metal parts 520. Fig. 9 is a cross-sectional view showing an example of the arrangement of the through holes 514 and the metal parts 520 in the fifth embodiment.

[0077] 9(a), the through holes 514 and the metal portions 520 are alternately arranged along a second direction perpendicular to the first direction. When viewed from the first direction, the through holes 514 and the metal portions 520 form a triangular lattice.

[0078] 9(b), through holes 514 and pairs of metal portions 520 are alternately arranged along a second direction perpendicular to the first direction. When viewed from the first direction, the through holes 514 and the metal portions 520 form a triangular lattice. Each through hole 514 is surrounded by six metal portions 520.

[0079] (Sixth embodiment) A sixth embodiment will be described. The sixth embodiment relates to a latent heat storage material. Fig. 10 is a diagram illustrating a latent heat storage material according to the sixth embodiment. Fig. 10(a) is a perspective view, and Fig. 10(b) is a cross-sectional view. Fig. 11 is a perspective view showing a metal part included in the latent heat storage material according to the sixth embodiment.

[0080] As shown in FIGS. 10 and 11, the latent heat storage material 6 according to the sixth embodiment has a ceramic part 610 made of a polycrystalline material and a metal part 620.

[0081] A closed space 611 is formed in the ceramic part 610. The ceramic part 610 has a substantially rectangular parallelepiped shape. A plurality of through holes 614 extending in a first direction are formed in the ceramic part 610. The first direction is perpendicular to a pair of parallel planes of the ceramic part 610. The through holes 614 are arranged at equal intervals in two directions (one in a second direction and the other in a third direction) perpendicular to the first direction. The closed space 611 has a bellows shape extending in the second direction. The closed space 611 is formed to weave between the regularly arranged through holes 614. The closed space 611 has a portion extending in the second direction and a portion extending in the third direction, and the portions extending in the second direction and the portions extending in the third direction are alternately connected. A plurality of closed spaces 611 are formed side by side in the first direction. Adjacent closed spaces 611 in the first direction may be connected to each other. The ceramic part 610 is, for example, integrally formed. For example, the ceramic portion 610 does not have a joint portion that connects to the closed space 611. The ceramic portion 610 is made of the same material as the ceramic portion 110.

[0082] The metal part 620 is provided in the closed space 611. In other words, the metal part 620 is sealed in the ceramic part 610. It can also be said that the metal part 620 is airtightly covered by the ceramic part 610, which is a continuous body. The metal part 620 has a bellows shape extending in the second direction. The metal part 620 is provided so as to thread between the regularly arranged through holes 614. The metal part 620 has a portion extending in the second direction and a portion extending in the third direction, and the portions extending in the second direction and the portions extending in the third direction are alternately connected. A plurality of the metal parts 620 are provided side by side in the first direction. Adjacent metal parts 620 in the first direction may be connected to each other.

[0083] The volume of the closed space 611 is preferably larger than the volume of the metal part 620. When the volume of the closed space 611 is larger than the volume of the metal part 620, a gap exists between the surface of the metal part 620 and the inner surface of the closed space 611, although this is not shown in Fig. 10. The gap between the surface of the metal part 620 and the inner surface of the closed space 611 may exist in only one location, or in multiple locations.

[0084] Other configurations are the same as those of Embodiment 1. Furthermore, the latent heat storage material 6 according to the sixth embodiment can be manufactured by the same method as that of Embodiment 1, except for the shape.

[0085] The sixth embodiment can also achieve the same effects as the first embodiment. Furthermore, the plurality of through holes 614 can be used as a flow path for the heat medium. In this case, it is easy to stabilize the flow rate and flow speed of the heat medium.

[0086] (Seventh embodiment) A seventh embodiment will be described. The seventh embodiment relates to a latent heat storage material. Fig. 12 is a diagram illustrating a latent heat storage material according to the seventh embodiment. Fig. 12(a) is a perspective view, and Fig. 12(b) is a cross-sectional view. Fig. 13 is a perspective view showing a metal part included in the latent heat storage material according to the seventh embodiment.

[0087] As shown in FIGS. 12 and 13, the latent heat storage material 7 according to the seventh embodiment has a ceramic part 710 made of a polycrystalline material and a metal part 720.

[0088] A closed space 711 is formed in the ceramic part 710. The ceramic part 710 has a substantially rectangular parallelepiped shape. A plurality of through holes 714 extending in a first direction are formed in the ceramic part 710. The first direction is perpendicular to a pair of parallel planes of the ceramic part 710. The through holes 714 are arranged at equal intervals in two directions (one in a second direction and the other in a third direction) perpendicular to the first direction. The closed space 711 has a bellows shape extending in the first direction. When a plurality of imaginary planes 715 on which a plurality of adjacent through holes 714 are arranged in the third direction are assumed, the closed space 711 is formed between adjacent imaginary planes 715 in the second direction. The closed space 711 has a portion extending in the first direction and a portion extending in the third direction, and the portions extending in the first direction and the portions extending in the third direction are alternately connected. A plurality of closed spaces 711 are formed lined up in the second direction. The closed spaces 711 adjacent to each other in the second direction may be connected to each other. The ceramic portion 710 is, for example, integrally formed. For example, the ceramic portion 710 does not have a joint portion connecting to the closed spaces 711. The ceramic portion 710 is made of the same material as the ceramic portion 110.

[0089] The metal part 720 is provided in the closed space 711. In other words, the metal part 720 is sealed in the ceramic part 710. It can also be said that the metal part 720 is airtightly covered by the ceramic part 710, which is a continuous body. The metal part 720 has a bellows shape extending in the first direction. The metal part 720 is provided between adjacent imaginary planes 715 in the second direction. The metal part 720 has a portion extending in the first direction and a portion extending in the third direction, and the portions extending in the first direction and the portions extending in the third direction are alternately connected. A plurality of the metal parts 720 are provided side by side in the second direction. Adjacent metal parts 720 in the second direction may be connected to each other.

[0090] The volume of the closed space 711 is preferably larger than the volume of the metal part 720. When the volume of the closed space 711 is larger than the volume of the metal part 720, a gap exists between the surface of the metal part 720 and the inner surface of the closed space 711, although this is not shown in Fig. 12. The gap between the surface of the metal part 720 and the inner surface of the closed space 711 may exist in only one location, or may exist in multiple locations.

[0091] Other configurations are the same as those of Embodiment 1. Furthermore, the latent heat storage material 7 according to the seventh embodiment can be manufactured by the same method as that of Embodiment 1, except for the shape.

[0092] The seventh embodiment can also achieve the same effects as the first embodiment. Furthermore, the plurality of through holes 714 can be used as a flow path for the heat medium. In this case, it is easy to stabilize the flow rate and flow speed of the heat medium.

[0093] (Eighth embodiment) An eighth embodiment will be described. The eighth embodiment relates to a latent heat storage material. Fig. 14 is a cross-sectional view illustrating an example of a latent heat storage material according to the eighth embodiment.

[0094] As shown in FIG. 14, the latent heat storage material 8 according to the eighth embodiment has a ceramic part 110 made of a polycrystalline body, a metal part 120, and an electric heater 830 capable of heating the metal part 120.

[0095] The heating element 830 is provided in the ceramic portion 110. The heating element 830 is provided, for example, near one of the pair of largest surfaces of the metal portion 120. The heating element 830 contains, for example, a mixture of tungsten and aluminum oxide, or a mixture of molybdenum and aluminum oxide. In this case, the heating element 830 may further contain one or more of silicon oxide, magnesium oxide, calcium carbonate, etc. The heating element 830 is an example of a heater.

[0096] The other configurations are the same as those in the first embodiment.

[0097] In manufacturing the latent heat storage element 8 according to the eighth embodiment, for example, tungsten or molybdenum powder is mixed with aluminum oxide powder, and organic components such as a solvent and a binder are added to prepare a paste. A heater paste portion having the shape of the heater 830 is then formed by screen printing or the like. The heater paste portion is then fired simultaneously with the ceramic portion 130 and the metal portion 140 in a neutral or reducing atmosphere. The resistivity of the heater 830 can be adjusted depending on the amount of aluminum oxide. One or more of silicon oxide, magnesium oxide, calcium carbonate, etc. may also be added to the paste. These inorganic components form a liquid phase or a composite oxide phase during firing, which can improve the adhesive strength of the heater 830 to the ceramic portion 130 and improve the stability of the resistivity.

[0098] The eighth embodiment can also achieve the same effects as the first embodiment. Furthermore, since the electric heater 830 can heat the metal part 120, it is possible to convert externally applied electric energy into heat and store it in the latent heat storage material 8. For example, by generating heat from the electric heater 830 using surplus power, the surplus power can be stored as heat. The energy stored in the latent heat storage material 8 can then be supplied to factories, offices, commercial buildings, etc. as heat, steam (pressure), or electricity (such as turbine power generation using steam pressure).

[0099] Furthermore, energy loss can be reduced because the latent heat storage material 8 includes the electric heating material 830. For example, if the electric heating material and the latent heat storage material are separated, the heat generated from the electric heating material is transferred to the latent heat storage material as hot air or the like, which tends to result in energy loss, but in this embodiment, such energy loss can be suppressed.

[0100] The resistivity of the electric heating element 830 can be adjusted not only by adjusting the content of aluminum oxide, but also by the cross-sectional area and length of the electric heating element 830, etc.

[0101] (First modified example of the eighth embodiment) A first modified example of the eighth embodiment will be described below. Fig. 15 is a cross-sectional view illustrating a latent heat storage material according to the first modified example of the eighth embodiment.

[0102] 15, the latent heat storage material 8A according to the first modified example of the eighth embodiment has a ceramic part 110 made of a polycrystalline body, a metal part 120, and two electric heating elements 830 capable of heating the metal part 120. One electric heating element 830 is provided near one side of the largest pair of faces of the metal part 120, and the other electric heating element 830 is provided near the other side of the largest pair of faces of the metal part 120.

[0103] The other configurations are the same as those of the eighth embodiment.

[0104] The first modified example of the eighth embodiment can also provide the same effects as those of the eighth embodiment. Furthermore, according to the first modified example of the eighth embodiment, the metal part 120 can be heated more easily.

[0105] (Second modified example of the eighth embodiment) A second modified example of the eighth embodiment will be described below. Fig. 16 is a cross-sectional view illustrating a latent heat storage material according to a second modified example of the eighth embodiment.

[0106] In a latent heat storage material 8B according to a second modification of the eighth embodiment, as shown in Fig. 16, an electric heating element 830 is provided on the surface of the ceramic portion 110. The electric heating element 830 is provided, for example, near one of the pair of largest faces of the metal portion 120. The electric heating element 830 contains, for example, molybdenum disilicide, ruthenium oxide, nickel-chromium alloy, or silver-palladium alloy. In this case, the electric heating element 830 may further contain glass.

[0107] The other configurations are the same as those in the first embodiment.

[0108] In manufacturing the latent heat storage unit 8B according to the second modification of the eighth embodiment, for example, after simultaneously firing the ceramic part 130 and the metal part 140, a paste is prepared by adding organic components such as a solvent and a binder to molybdenum disilicide, ruthenium oxide, a nickel-chromium alloy, or a silver-palladium alloy, and a paste part for the heater having the shape of the heater 830 is formed by a screen printing method or the like. The paste part for the heater is then fired. This firing may be performed in an oxidizing atmosphere such as the air atmosphere. Glass may be added to the paste part for the heater. Platinum may be used as the material for the heater 830, or the same material as in the eighth embodiment may be used.

[0109] Two electric heating elements 830 may be provided on two surfaces of the ceramic portion 110. For example, one electric heating element 830 may be provided near one of the largest pair of surfaces of the metal portion 120, and the other electric heating element 830 may be provided near the other of the largest pair of surfaces of the metal portion 120.

[0110] (Ninth embodiment) A ninth embodiment will be described. The ninth embodiment relates to a latent heat storage material. Fig. 17 is a diagram illustrating a latent heat storage material according to the ninth embodiment. Fig. 17(a) is a perspective view, and Fig. 17(b) is a cross-sectional view.

[0111] As shown in Figures 17(a) and 17(b), the latent heat storage material 9 of the ninth embodiment has a ceramic part 110 made of a polycrystalline body, a metal part 120, and an electric heating element 930 that can heat the metal part 120.

[0112] The electric heating element 930 is provided in the ceramic portion 110. The electric heating element 930 is provided, for example, near one of the pair of largest surfaces of the metal portion 120. The electric heating element 930 is arranged in a bellows shape. The electric heating element 930 is made of the same material as the electric heating element 830. The electric heating element 930 is an example of a heater.

[0113] Other configurations are the same as those of the eighth embodiment. Furthermore, the latent heat storage material 9 according to the ninth embodiment can be manufactured by the same method as that of the eighth embodiment, except for the shape.

[0114] The ninth embodiment can also provide the same effects as the eighth embodiment. Furthermore, since the electric heating element 930 is arranged in a bellows shape, a larger amount of heat can be generated.

[0115] Here, an example of a method of using the latent heat storage material 9 according to the ninth embodiment will be described. Fig. 18 is a diagram illustrating a method of using the latent heat storage material 9 according to the ninth embodiment. Fig. 18(a) is a perspective view, and Fig. 18(b) is a top view.

[0116] In this example, as shown in Figures 18(a) and 18(b), multiple latent heat storage materials 9 having the same shape are used. The multiple latent heat storage materials 9 are lined up in a row, and the largest surfaces of adjacent latent heat storage materials 9 face each other.

[0117] During heat storage, heat is generated from the electric heater 930, causing the metal part 120 to melt. When the heat stored in the latent heat storage material 9 is to be utilized, a heat medium 960 having a temperature lower than the melting point of the metal part 120 is supplied toward the latent heat storage material 9, as shown in FIGS. 18(a) and 18(b). The heat medium 960 is heated by the latent heat storage material 9, and moves away from the latent heat storage material 9 in a state in which it has more thermal energy than when it was supplied. In this way, thermal energy can be transferred to the heat medium 960.

[0118] (Tenth embodiment) A tenth embodiment will be described. The tenth embodiment relates to a latent heat storage material. Fig. 19 is a perspective view illustrating a latent heat storage material according to the tenth embodiment.

[0119] As shown in FIG. 19 , the latent heat storage material 10 according to the tenth embodiment includes a ceramic portion 210 made of a polycrystalline material, a metal portion 220, and an electric heater 1030 capable of heating the metal portion 220. The electric heater 1030 is provided between the surface of the ceramic portion 210 and the surface of the metal portion 220. The electric heater 1030 has a substantially cylindrical shape. When viewed from a direction parallel to the long axis of the columnar metal portion 220, the electric heater 1030 forms a spiral, for example, by alternately rotating clockwise and counterclockwise. The electric heater 1030 is made of the same material as the electric heater 830. The electric heater 1030 is an example of a heater.

[0120] Other configurations are the same as those of the eighth embodiment. Furthermore, the latent heat storage material 10 according to the tenth embodiment can be manufactured by a method generally similar to that of the eighth embodiment, except for the shape. The portion (circumferential portion) perpendicular to the long axis of the metal portion 220 of the electric heater 1030 can be formed, for example, by a resistor paste printed on the surface of a ceramic green sheet. The portion extending parallel to the long axis of the metal portion 220 of the electric heater 1030 can be formed, for example, by a resistor paste filled in through holes formed in a ceramic green sheet.

[0121] The ninth embodiment can also provide the same effects as the eighth embodiment. Furthermore, since the electric heating element 1030 is formed in a spiral shape, a larger amount of heat can be generated.

[0122] Alternatively, the ceramic part 210 and the metal part 220 may have a rectangular columnar shape, and the electric heater 1030 may have a substantially rectangular cylindrical shape.

[0123] Here, an example of a method of using the latent heat storage material 10 according to the tenth embodiment will be described. Fig. 20 is a diagram illustrating a method of using the latent heat storage material according to the tenth embodiment.

[0124] In this example, a plurality of latent heat storage materials 10 having the same shape are used, as shown in Fig. 20. The plurality of latent heat storage materials 10 are arranged in a plane parallel to the bottom surface of the ceramic portion 210.

[0125] During heat storage, heat is generated from the electric heater 1030, causing the metal part 120 to melt. When the heat stored in the latent heat storage material 10 is to be utilized, a heat medium 1060 having a temperature lower than the melting point of the metal part 120 is supplied toward the latent heat storage material 10, as shown in FIG. 20 . The heat medium 1060 is supplied, for example, parallel to the bottom surface of the ceramic part 210. The heat medium 1060 is heated by the latent heat storage material 10, and moves away from the latent heat storage material 10 with more thermal energy than when it was supplied. In this way, thermal energy can be transferred to the heat medium 1060.

[0126] Alternatively, the heat medium 1060 may be supplied perpendicularly to the bottom surface of the ceramic portion 210 .

[0127] (Eleventh embodiment) An eleventh embodiment will be described. The eleventh embodiment relates to a latent heat storage material. Fig. 21 is a perspective cross-sectional view illustrating a latent heat storage material according to the eleventh embodiment.

[0128] As shown in Figure 21, the latent heat storage material 10 of the 11th embodiment has a ceramic part 1110 made of a polycrystalline material, a plurality of metal parts 1120, and a plurality of electric heating elements 1130 that can heat the metal parts 1120.

[0129] A plurality of closed spaces 1111 are formed in the ceramic part 1110. The closed spaces 1111 are cylindrical in shape. The plurality of closed spaces 1111 extend in the same direction. A through hole 1114 extending parallel to the closed spaces 1111 is formed in the ceramic part 1110. The closed spaces 1111 are provided near the through hole 1114. The ceramic part 1110 is, for example, formed as an integral unit. For example, the ceramic part 1110 does not have any joints connecting to the closed spaces 1111. The ceramic part 1110 is made of the same material as the ceramic part 110.

[0130] Each metal part 1120 is provided in the closed space 1111. In other words, the metal part 1120 is sealed in the ceramic part 1110. It can also be said that the metal part 1120 is airtightly covered by the ceramic part 1110, which is a continuous body. The metal part 1120 has a columnar shape. The metal part 1120 is made of the same material as the metal part 120.

[0131] The volume of the closed space 1111 is preferably larger than the volume of the metal part 1120. When the volume of the closed space 1111 is larger than the volume of the metal part 1120, a gap exists between the surface of the metal part 1120 and the inner surface of the closed space 1111, although this is omitted in Fig. 21. The gap between the surface of the metal part 1120 and the inner surface of the closed space 1111 may exist in only one location, or in multiple locations.

[0132] The electric heating element 1130 is provided in the ceramic portion 1110. The electric heating element 1130 has a substantially cylindrical shape, similar to the electric heating element 1030, and when viewed from a direction parallel to the long axis of the columnar metal portion 1120, forms a spiral, for example, alternating clockwise and counterclockwise. The electric heating element 1130 is made of the same material as the electric heating element 830. The electric heating element 1130 is an example of a heater.

[0133] The latent heat storage material 11 according to the eleventh embodiment can be manufactured by the same method as that of the eleventh embodiment, except for the shape.

[0134] During heat storage, heat is generated from the electric heater 1130, causing the metal part 1120 to melt. When the heat stored in the latent heat storage material 11 is to be used, a heat medium with a temperature lower than the melting point of the metal part 1120 is supplied into the through holes 1114. The heat medium is heated by the latent heat storage material 11, and moves away from the latent heat storage material 11 in a state where it has more thermal energy than when it was supplied. In this way, thermal energy can be transferred to the heat medium.

[0135] The eleventh embodiment can also achieve the same effects as the tenth embodiment.

[0136] (Twelfth embodiment) A twelfth embodiment will be described. The twelfth embodiment relates to a latent heat storage material. Fig. 22 is a cross-sectional view illustrating a latent heat storage material according to the twelfth embodiment.

[0137] As shown in FIG. 22, the latent heat storage material 12 according to the twelfth embodiment has a ceramic part 110 made of a polycrystalline body, a metal part 120, and a thermocouple 1240 that generates electricity in response to a temperature change in the metal part 120.

[0138] Thermocouple 1240 has first conductor 1241 and second conductor 1242. One end of first conductor 1241 is connected to one end of second conductor 1242. First conductor 1241 and second conductor 1242 have different thermoelectric powers. For example, first conductor 1241 and second conductor 1242 contain a tungsten-rhenium alloy, with first conductor 1241 being composed of 5% by mass of rhenium and 95% by mass of tungsten, and second conductor 1242 being composed of 26% by mass of rhenium and 74% by mass of tungsten.

[0139] The other configurations are the same as those in the first embodiment.

[0140] When manufacturing the latent heat storage material 12 according to the twelfth embodiment, for example, a paste for the first conductors 1241 and a paste for the second conductors 1242 are mixed, and a thermocouple paste portion having the shape of the thermocouple 1240 is formed by a screen printing method or the like. Then, the thermocouple paste portion is fired simultaneously with the ceramic portion 130 and the metal portion 140.

[0141] The twelfth embodiment can also achieve the same effects as the first embodiment. Furthermore, since the thermocouple 1240 is provided, the state of the metal part 120 can be easily grasped. For example, during the heat storage process, while the metal part 120 is solid, the temperature indicated by the thermocouple 1240 increases over time. However, while the metal part 120 is undergoing a phase change from solid to liquid, the temperature indicated by the thermocouple 1240 remains stable. After that, once the phase change is complete, the temperature indicated by the thermocouple 1240 increases again over time. Therefore, it is easy to grasp whether the phase change has started, is continuing, or is complete.

[0142] In the latent heat storage material, even if the metal part that has completed the phase change and become liquid is further heated, latent heat cannot be stored, and there is a risk that the input energy will be wasted. In contrast, in this embodiment, since the completion of the phase change can be detected using the thermocouple 1240, if heat is stored in another latent heat storage material 12 after the phase change is completed, it is possible to suppress the waste of energy.

[0143] (First modified example of the twelfth embodiment) A first modified example of the twelfth embodiment will be described below. Fig. 23 is a cross-sectional view illustrating a latent heat storage material according to a first modified example of the twelfth embodiment.

[0144] 23, the latent heat storage material 12A according to the first modification of the twelfth embodiment has a ceramic part 110 made of a polycrystalline body, a metal part 120, a thermocouple 1240 that generates electricity in response to a temperature change in the metal part 120, and an electric heating element 830 that can heat the metal part 120. The electric heating element 830 is provided near one of a pair of largest surfaces of the metal part 120, for example.

[0145] The other configurations are the same as those of the twelfth embodiment.

[0146] The first modified example of the 12th embodiment can also provide the same effects as those of the 12th embodiment. Furthermore, according to the first modified example of the 12th embodiment, similar to the eighth embodiment, the latent heat storage material 12A includes the electric heating material 830, and therefore, energy loss can be reduced.

[0147] (Second modified example of the twelfth embodiment) A second modification of the twelfth embodiment will be described below. Fig. 24 is a cross-sectional view illustrating a latent heat storage material according to a second modification of the twelfth embodiment.

[0148] In a latent heat storage material 12B according to a second modification of the twelfth embodiment, as shown in FIG. 24, a flow path 1214 through which the heat medium flows is formed in the ceramic part 110.

[0149] The second modification of the twelfth embodiment can also provide the same effects as those of the twelfth embodiment. Furthermore, since the flow paths 1214 are formed, the efficiency of heat exchange between the heat medium flowing through the flow paths 1214 and the metal part 120 can be improved.

[0150] (Thirteenth embodiment) A thirteenth embodiment will be described. The thirteenth embodiment relates to a latent heat storage material, and corresponds to an application example of the twelfth embodiment. Fig. 25 is a cross-sectional view illustrating a latent heat storage material according to the thirteenth embodiment.

[0151] 25, the latent heat storage material 13 according to the thirteenth embodiment has a ceramic part 110 made of a polycrystalline body, a metal part 120, a thermocouple 1240 that generates electricity in response to a temperature change in the metal part 120, and a heat-insulating container 150. The ceramic part 110 is housed in the heat-insulating container 150. The heat-insulating container 150 is provided with a heat inlet 151 and a heat outlet 152.

[0152] Here, an example of a method of using the latent heat storage material 13 according to the thirteenth embodiment will be described. Fig. 26 is a diagram illustrating a method of using the latent heat storage material 13 according to the thirteenth embodiment. In Fig. 26, the metal part 120 has a matte finish, and the denser the matte finish, the higher the temperature.

[0153] In this example, as shown in Figure 26(a), multiple latent heat storage materials 13 are used. The inlets 151 and outlets 152 of the multiple latent heat storage materials 13 are alternately connected in series to form a heat transfer system (series). The temperature of the metal part 120 decreases from the latent heat storage material 13 connected most upstream in the heat transfer direction toward the downstream. In each latent heat storage material 13, the state of phase change of the metal part 120 can be detected using a thermocouple 1240.

[0154] When the completion of the phase change is detected in the most upstream latent heat storage material 13, as shown in Figure 26(b), that latent heat storage material 13 is disconnected from the heat transfer system and either retains the heat as is or is used for an application that requires the use of heat. If the heat is retained as is, it is preferable to block the inlet 151 and the outlet 152. On the other hand, heat is made to flow directly into the latent heat storage material 13 that was connected second from the upstream side, and this latent heat storage material 13 becomes the most upstream latent heat storage material 13. Thereafter, although not shown in the figures, the latent heat storage materials 13 for which the completion of the phase change is detected are sequentially disconnected from the heat transfer system.

[0155] According to the thirteenth embodiment, in this way, heat can be stored in the multiple latent heat storage materials 13 while suppressing waste of thermal energy.

[0156] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0157] 1, 2, 3, 4, 5, 6, 7, 8, 8A, 8B, 9, 10, 11, 12, 12A, 12B, 13 Latent heat storage material 110, 130, 210, 250A, 250B, 310, 350A, 350B, 410, 510, 610, 710, 1110 Ceramic part 120, 140, 220, 260, 320, 360, 420, 520, 620, 720, 1120 Metal parts 111, 131, 211, 311, 411, 511, 611, 711, 1111 Closed space 150 Insulated Container 414, 514, 614, 714, 1114 through holes 1130 Electric heating element 1240 thermocouple

Claims

1. a ceramic portion made of a polycrystalline body in which a closed space is formed; a metal portion containing aluminum provided in the closed space; A latent heat storage material having the above structure.

2. The latent heat storage material according to claim 1 , wherein the volume of the closed space is larger than the volume of the metal portion.

3. 3. The latent heat storage material according to claim 2, wherein the volume of the closed space at 25°C is 114% or more and 120% or less of the volume of the metal portion.

4. 3. The latent heat storage material according to claim 1, wherein the metal portion contains aluminum at a ratio of 99 mass % or more.

5. 3. The latent heat storage material according to claim 1, wherein the ceramic portion contains aluminum oxide at a ratio of 96 mass % or more.

6. the ceramic portion has a cylindrical shape with an inner wall surface and an outer wall surface, The latent heat storage material according to claim 1 or 2, wherein the closed space and the metal portion have a spiral shape along the inner wall surface and the outer wall surface.

7. A plurality of through holes extending in a first direction are formed in the ceramic portion, The closed space and the metal portion have a columnar shape parallel to the first direction, The latent heat storage material according to claim 1 or 2, comprising a plurality of pairs of the closed space and the metal portion.

8. A plurality of through holes extending in a first direction are formed in the ceramic portion, The latent heat storage material according to claim 1 or 2, wherein the closed space and the metal portion have a bellows shape extending in a second direction perpendicular to the first direction.

9. A plurality of through holes extending in a first direction are formed in the ceramic portion, The latent heat storage material according to claim 1 , wherein the closed space and the metal portion have a bellows shape extending in the first direction.

10. 3. The latent heat storage material according to claim 1, further comprising a heater capable of heating the metal portion.

11. The latent heat storage material according to claim 10, wherein the heater is provided within the ceramic portion.

12. The latent heat storage material according to claim 10, wherein the heater is provided on a surface of the ceramic portion.

13. The latent heat storage medium according to claim 10, wherein the heater contains a mixture of tungsten and aluminum oxide or a mixture of molybdenum and aluminum oxide.

14. The latent heat storage medium according to claim 10, wherein the heater contains molybdenum disilicide, ruthenium oxide, a nickel-chromium alloy, or a silver-palladium alloy.

15. The latent heat storage material according to claim 14, wherein the heater further contains glass.

16. 3. The latent heat storage material according to claim 1, further comprising a thermocouple that generates electric power in response to a temperature change in the metal portion.

17. The latent heat storage material according to claim 16, wherein the thermocouple is provided within the ceramic portion.

18. The latent heat storage material according to claim 16, wherein the thermocouple is provided on a surface of the ceramic portion.

19. The latent heat storage medium according to claim 16, wherein the thermocouple contains a tungsten-rhenium alloy.

20. The latent heat storage material according to claim 16, further comprising a heater capable of heating the metal portion.

21. The latent heat storage material according to claim 16, wherein the ceramic portion has a flow path through which the heat medium flows.

22. The ceramic portion has a pair of main surfaces parallel to each other, A plurality of the closed spaces are formed in a plane parallel to the main surface, 3. The latent heat storage material according to claim 1, wherein a plurality of said metal parts are provided in each of said plurality of closed spaces.

23. Providing a composite body having an aluminum-containing metal part and an unfired ceramic part housing the metal part; co-firing the metal portion and the ceramic portion; A method for producing a latent heat storage material having the above structure.

24. The method for producing a latent heat storage medium according to claim 23, wherein the metal portion contains aluminum at a ratio of 99 mass % or more.

25. The method for producing a latent heat storage medium according to claim 23 or 24, wherein the ceramic portion contains aluminum oxide at a ratio of 96 mass % or more.

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