Heat generating structure and heat generating device

Abstract

Provided are a heat generating structure and a heat generating device capable of uniformizing a temperature distribution of a heat generating body. A heat generating structure 8 comprises: a heat-generating body 14 which generates heat by storing and releasing hydrogen; a heater 15 which has a heat generating surface generating radiant heat; and reflection parts 16a, 16b which are provided adjacent to the heat-generating body 14 and which reflect the radiant heat. The heat generating body 14 has: a support body which is formed of a hydrogen-storing metal, a hydrogen-storing alloy, or a proton conductor; and a multilayer film which is provided to the support body. The multilayer film has: a first layer which is formed of a hydrogen-storing metal or a hydrogen-storing alloy and which has a thickness of less than 1000 nm; and a second layer which is formed of a hydrogen-storing metal or a hydrogen-storing alloy different from that of the first layer, or a ceramic, and which has a thickness of less than 1000 nm. The heat generating surface has first heat generating regions R1a, R1b which are covered by the reflection parts 16a, 16b and in which a first temperature distribution occurs, and a second heat-generating region R2 which is covered by the heat-generating body 14 and in which a second temperature distribution more uniform than the first temperature distribution occurs.

Description

Heat-generating structure and heat-generating device

[0001] The present invention relates to a heat generating structure and a heat generating device.

[0002] Recently, a heat generating device has been proposed that includes a sealed container to which a hydrogen-containing gas is supplied, a heating element that generates heat by absorbing and releasing hydrogen, and a cylindrical heater (see Patent Document 1). The heating element is a wound heating element formed by winding a plate-shaped member and is arranged to cover a portion of the outer circumferential surface of the heater. The heating element and heater are housed in a sealed container. The heating element includes a base formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on the base. The multilayer film includes a first layer formed of a hydrogen storage metal or a hydrogen storage alloy and having a thickness of less than 1000 nm, and a second layer formed of a hydrogen storage metal, a hydrogen storage alloy, or a ceramic different from the first layer and having a thickness of less than 1000 nm. A heterogeneous material interface is formed between the first and second layers. In the heat generating device of Patent Document 1, after hydrogen is absorbed into the heat generating element, the inside of the sealed container is evacuated and the heat generating element is heated, causing the hydrogen to permeate the interface of different materials in the heat generating element by quantum diffusion, or the hydrogen to diffuse the interface of different materials by quantum diffusion, generating excess heat.

[0003] On the other hand, the inventors of the present application have found that there is a correlation between the temperature of the heating element and the generation of excess heat, and that the higher the temperature of the heating element, the more excess heat tends to be generated. If the temperature of the heating element is too high, the heating element will reach its melting point and be damaged, so when heating the heating element with a heater, it is desirable to heat the heating element to a uniform temperature that is high enough not to damage it.

[0004] WO 2023 / 149220

[0005] The heating device of Patent Document 1 can efficiently heat the heating element by radiant heat generated from the outer circumferential surface of the cylindrical heater. However, in the heating device of Patent Document 1, different temperature distributions occur between the area of ​​the outer circumferential surface of the heater that is covered by the heating element and the area that is not covered by the heating element, which can result in uneven temperature distribution of the heating element heated by the radiant heat of the heater, and reduced heating efficiency.

[0006] An object of the present invention is to provide a heat generating structure and a heat generating device that can make the temperature distribution of a heat generating element uniform.

[0007] The heating structure according to the present invention comprises a heating element that generates heat by absorbing and releasing hydrogen, a heater having a heating surface that generates radiant heat and that heats the heating element with the radiant heat, and a reflecting portion disposed adjacent to the heating element and that reflects the radiant heat, the heating element having a support formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film disposed on the support, the multilayer film having a first layer less than 1000 nm in thickness formed of a hydrogen storage metal or a hydrogen storage alloy, and a second layer less than 1000 nm in thickness formed of a hydrogen storage metal, a hydrogen storage alloy, or a ceramic different from the first layer, the heating surface having a first heating region in which a first temperature distribution occurs and a second heating region in which a second temperature distribution more uniform than the first temperature distribution occurs, the second heating region being covered by the heating element and the first heating region being covered by the reflecting portion.

[0008] The heat generating device according to the present invention comprises the above-mentioned heat generating structure, a sealed container that houses the heat generating structure, a supply unit that supplies a hydrogen-based gas containing hydrogen into the sealed container, and an exhaust unit that exhausts the hydrogen-based gas from inside the sealed container.

[0009] According to the present invention, the temperature distribution of the heating element can be made uniform.

[0010] 14 is a conceptual diagram showing an outline of the configuration of a heat utilization system according to the first embodiment. FIG. 15 is a cross-sectional view showing the configuration of a heat generating element. FIG. 16 is an explanatory diagram for explaining the heat generating surface of a heater. FIG. 17 is a graph showing the temperature distribution of heat generating elements according to the present embodiment and a comparative example. FIG. 18 is a conceptual diagram showing an outline of the configuration of a heat utilization system according to the second embodiment. FIG. 19 is a conceptual diagram showing an outline of the configuration of a heat utilization system according to the third embodiment. FIG. 19 is a conceptual diagram showing an outline of the configuration of a heat utilization system according to the fourth embodiment. FIG. 19 is a conceptual diagram showing an outline of the configuration of a heat utilization system according to the fifth embodiment. FIG. 19 is a perspective view of a heat generating structure according to the fifth embodiment. FIG. 19 is a cross-sectional view taken along line X-X shown in FIG. 9. FIG. 19 is an explanatory diagram for explaining an example of a manufacturing method of a heat generating structure. FIG. 19 is an explanatory diagram for explaining an example of a manufacturing method of a heat generating structure. FIG. 19 is a conceptual diagram showing an outline of the configuration of a heat utilization system according to the sixth embodiment. FIG. 19 is a cross-sectional view taken along line XV-XV shown in FIG. 14. FIG. 20 is a graph showing the temperature distribution of heat generating structures according to the sixth embodiment and a comparative example.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description and drawings, common components are designated by common reference numerals. Descriptions of components designated by common reference numerals will be omitted as appropriate.

[0012] (1) Heat Utilization System According to the First Embodiment In Fig. 1, the heat utilization system 1 includes a piping path 2 through which a heat medium flows, a heat generating device 3 that heats the heat medium flowing through the piping path 2, and a heat utilization device 4 that uses the heat medium heated by the heat generating device 3 as a heat source. The heat generating device 3 and the heat utilization device 4 are incorporated into the piping path 2. The piping path 2 forms a sealed circulation path between the heat generating device 3 and the heat utilization device 4.

[0013] The heat transfer medium may be a gas or a liquid, and is preferably one that has excellent thermal conductivity and is chemically stable. Examples of the gas that can be used include helium gas, argon gas, hydrogen gas, nitrogen gas, water vapor, air, and carbon dioxide. Examples of the liquid that can be used include water and molten salt (KNO ３ (40%)-NaNO ３(60%)), liquid metal (Pb, etc.), etc. may be used. Alternatively, a multiphase heat transfer medium in which solid particles are dispersed in a gas or liquid may be used as the heat transfer medium. The solid particles may be metals, metal compounds, alloys, ceramics, etc. Metals may include Cu, Ni, Ti, Co, etc. Metal compounds may include oxides, nitrides, silicides, etc. of the above metals. Alloys may include stainless steel, chromium molybdenum steel, etc. Ceramics may include alumina, etc. In this embodiment, helium gas is used as the heat transfer medium, but this may be changed as appropriate within the scope of the present invention.

[0014] The heat generating device 3 comprises a hollow sealed container 5 , a hydrogen tank 6 connected to the sealed container 5 , a vacuum pump 7 connected to the sealed container 5 , and a heat generating structure 8 housed in the sealed container 5 .

[0015] The sealed container 5 is heat-resistant and pressure-resistant. The sealed container 5 is made of, for example, stainless steel, heat-resistant non-ferrous alloy steel, or the like. A material appropriate for the operating temperature is used for the sealed container 5. For example, stainless steel is used when the operating temperature is up to about 700°C, and heat-resistant non-ferrous alloy steel is used when the operating temperature exceeds 700°C. The sealed container 5 is cylindrical. The sealed container 5 is composed of a body, an upper lid attached to the upper end of the body, and a lower lid attached to the lower end of the body. The upper end of the body is airtightly closed with the upper lid, and the lower end of the body is airtightly closed with the lower lid, thereby defining a space 9 inside the sealed container 5. The shape of the sealed container 5 is not limited to a cylindrical shape, and may be an elliptical cylinder, a rectangular cylinder, a sphere, or the like. In the heating device 3, the upper lid side of the sealed container 5 is referred to as the upper side, and the lower lid side of the sealed container 5 is referred to as the lower side.

[0016] The heat generating device 3 has an inlet pipe 10 that connects the sealed container 5 and the hydrogen tank 6, and an exhaust pipe 11 that connects the sealed container 5 and the vacuum pump 7. The inlet pipe 10 extends from the bottom lid of the sealed container 5 and is connected to the hydrogen tank 6, forming an inlet path that guides the hydrogen-based gas stored in the hydrogen tank 6 to the internal space 9 of the sealed container 5. The exhaust pipe 11 extends from the top lid of the sealed container 5 and is connected to the vacuum pump 7, forming an exhaust path that guides the hydrogen-based gas sucked into the vacuum pump 7 from the internal space 9 of the sealed container 5.

[0017] The inlet pipe 10 has a supply valve 12 provided between the sealed container 5 and the hydrogen tank 6. The supply valve 12 adjusts the flow rate of the hydrogen-based gas flowing through the inlet pipe 10. For example, an electromagnetic valve or an air valve is used as the supply valve 12. The inlet pipe 10 may have a pressure sensor that detects the pressure of the hydrogen-based gas flowing through the inlet pipe 10.

[0018] The exhaust pipe 11 has an exhaust valve 13 provided between the sealed container 5 and the vacuum pump 7. The exhaust valve 13 adjusts the flow rate of the hydrogen-based gas flowing through the exhaust pipe 11. For example, an electromagnetic valve or an air valve is used as the exhaust valve 13. The exhaust pipe 11 may have a pressure sensor that detects the pressure of the hydrogen-based gas flowing through the exhaust pipe 11.

[0019] When the exhaust valve 13 is closed and the supply valve 12 is opened, it becomes possible to supply hydrogen-based gas from the hydrogen tank 6 to the space 9 inside the sealed container 5. When the supply valve 12 is closed and the exhaust valve 13 is opened, it becomes possible to exhaust the hydrogen-based gas from the space 9 inside the sealed container 5 by the vacuum pump 7.

[0020] The hydrogen tank 6 stores a hydrogen-based gas. In this example, when the supply valve 12 is opened, the hydrogen-based gas is supplied from the high-pressure hydrogen tank 6 to the internal space 9 of the low-pressure sealed container 5 via the inlet pipe 10. The hydrogen-based gas is a gas containing hydrogen isotopes. At least one of deuterium gas and protium gas is used as the hydrogen-based gas. The protium gas includes a mixture of naturally occurring protium and deuterium, i.e., a mixture in which the abundance ratio of protium is 99.985% and the abundance ratio of deuterium is 0.015%. The inlet pipe 10 may have a pump that sends the hydrogen-based gas stored in the hydrogen tank 6 to the internal space 9 of the sealed container 5.

[0021] The vacuum pump 7 exhausts the hydrogen-based gas from the inside of the sealed container 5 through the exhaust pipe 11. The space 9 inside the sealed container 5 is depressurized by driving the vacuum pump 7. The vacuum pump 7 is composed of, for example, a turbomolecular pump and a dry pump. The turbomolecular pump adjusts the rotation speed of the turbine blades based on a control signal input from a control unit 21, which will be described later. The speed at which the space 9 is depressurized is adjusted according to the rotation speed of the turbomolecular pump.

[0022] The heat generating structure 8 heats the heat medium flowing along the outer surface of the sealed container 5 through the sealed container 5. The temperature of the heat medium heated by the heat generating structure 8 reaches a range of, for example, 50°C to 1500°C. In this example, the temperature of the heat medium is set to 700°C.

[0023] The heating structure 8 includes a heating element 14 that generates heat by absorbing and releasing hydrogen, a heater 15 that has a heating surface 15a that generates radiant heat and heats the heating element 14 with radiant heat, reflecting portions 16a and 16b that are provided adjacent to the heating element 14 and reflect the radiant heat, and a temperature sensor 17 that detects the temperature of the heating element 14.

[0024] The heating element 14 is formed in a cylindrical shape. The cross-sectional shape of the heating element 14 when cut along a plane perpendicular to the axial direction (hereinafter referred to as the cross-sectional shape of the heating element) is circular. In other words, the heating element 14 is formed in a cylindrical shape. The number of turns of the heating element 14 is one. The cross-sectional shape of the heating element 14 is not limited to a circular shape, and may be an elliptical shape, a polygonal shape, a spiral shape, or the like. When the cross-sectional shape of the heating element 14 is a spiral shape, the number of turns of the heating element 14 is two or more. In this example, the axial length of the heating element 14 is 300 mm, but is not particularly limited. The configuration of the heating element 14 will be described later using another drawing.

[0025] The heater 15 is formed in a rod shape. In this embodiment, the outer peripheral surface of the heater 15 is a cylindrical surface. The outer peripheral surface of the heater 15 is not limited to a cylindrical surface and may be an elliptical cylindrical surface, a rectangular cylindrical surface, or the like. Examples of the rod-shaped heater 15 include a sheathed heater, a ceramic heater, and a lamp heater. For example, a sheathed heater has a configuration in which a spirally wound heating wire is housed in a metal pipe. The heating wire is disposed in the pipe except for a portion within a predetermined distance from each end of the pipe in the axial direction. A pair of terminals connected to a power source is connected to both ends of the heating wire. The pair of terminals extends from the inside to the outside of the pipe. The heating wire generates Joule heat when a current is applied from the power source via the pair of terminals. The pipe is heated by the Joule heat generated by the heating wire.

[0026] The heating surface 15a of the heater 15 constitutes the outer peripheral surface of the heater 15 except for portions extending a predetermined distance from both ends of the heater 15 in the axial direction. Therefore, in this embodiment, the heating surface 15a is a cylindrical surface. The configuration of the heating surface 15a of the heater 15 will be described later using another drawing.

[0027] The heater 15 has a pair of electrode portions 20. The pair of electrode portions 20 are connected to conductive wires 18. The conductive wires 18 are connected to a power source 19, electrically connecting the pair of electrode portions 20 and the power source 19. The heater 15 receives power from the power source 19 via the conductive wires 18 and the pair of electrode portions 20, thereby increasing the temperature of the heating surface 15a. The heater 15 heats the heating element 14 by radiant heat generated from the heating surface 15a. In FIG. 1, the pair of electrode portions 20 are provided at both ends of the heater 15, but they may be provided at one end or the other end of the heater 15. In FIG. 1, the pair of electrode portions 20 extend from the inside to the outside of the sealed container 5, but they may be housed inside the sealed container 5. For example, a pair of connection terminals may be provided on the upper and lower lids of the sealed container 5, the pair of connection terminals may be connected to the conductive wires 18 outside the sealed container 5, and the pair of electrode portions 20 may be connected to the pair of connection terminals inside the sealed container 5.

[0028] The reflecting portion 16a is provided adjacent to the upper end of the heating element 14. The reflecting portion 16b is provided adjacent to the lower end of the heating element 14. The reflecting portions 16a and 16b have the same configuration. In the following description, when there is no need to distinguish between the reflecting portions 16a and 16b, they will be referred to as the reflecting portions 16.

[0029] The reflecting portion 16 is formed in a cylindrical shape. The cross-sectional shape of the reflecting portion 16 when cut along a plane perpendicular to the axial direction (hereinafter referred to as the cross-sectional shape of the reflecting portion) is circular. In other words, the reflecting portion 16 is formed in a cylindrical shape. The number of turns of the reflecting portion 16 is one. The cross-sectional shape of the reflecting portion 16 is not limited to a circular shape, and may be an elliptical shape, a polygonal shape, a spiral shape, or the like. When the cross-sectional shape of the reflecting portion 16 is a spiral shape, the number of turns of the reflecting portion 16 is two or more. It is preferable that the number of turns of the reflecting portion 16 is equal to or greater than the number of turns of the heating element 14. The axial length of the reflecting portion 16 is 70 mm in this example, but is not particularly limited.

[0030] The reflector 16 is formed of a low-emissivity material. Examples of low-emissivity materials include metals such as Ni, Mo, Cu, Au, Pd, Fe, Co, Pt, Os, Cr, V, Ti, and W, and alloys thereof. Examples of alloys include stainless steel such as SUS304 and nickel-based alloys such as NCF600. The reflector 16 is preferably formed of a material that has low emissivity and is heat-resistant and pressure-resistant. In this example, Ni foil is used as the reflector 16. The reflector 16 may also be configured by providing a reflective film made of a low-emissivity material on the surface of a heat-resistant and pressure-resistant base material, for example, by plating. Note that a low-emissivity material is synonymous with a high-reflectivity material.

[0031] The reflecting portion 16 is formed separately from the heating element 14. It is preferable that the reflecting portion 16 is disposed so that no space is formed between the reflecting portion 16 and the heating element 14.

[0032] The temperature sensor 17 outputs a detection signal that specifies the detected temperature. The temperature sensor 17 has, for example, a thermocouple embedded in the heating element 14. The thermocouple outputs a voltage that specifies the detected temperature.

[0033] In the heating structure 8, the heater 15 is formed in a rod shape, and the heating element 14 and the reflecting portion 16 are formed in a cylindrical shape. The heating surface 15a of the heater 15 is surrounded by the heating element 14 and the reflecting portion 16. The axial directions of the heating element 14, the heater 15, and the reflecting portion 16 are aligned with one another.

[0034] Here, an example of a configuration for supporting the heating element 14 and the reflecting portions 16a, 16b so as to cover the heating surface 15a of the heater 15 will be described. For example, a support (not shown) can be used to support the heating element 14 and the reflecting portions 16a, 16b so as to cover the heating surface 15a. The support is provided inside the sealed container 5. The support includes a pair of support columns, an upper fixing portion, a first intermediate fixing portion, a second intermediate fixing portion, and a lower fixing portion. The pair of support columns are formed in a rod shape. The pair of support columns are parallel to the axial direction of the heater 15 and are arranged line-symmetrically with respect to the heater 15, and are fixed to at least one of the upper lid and the lower lid of the sealed container 5. The upper fixing portion, the first intermediate fixing portion, the second intermediate fixing portion, and the lower fixing portion are each formed in an annular shape. The upper fixing portion, the first intermediate fixing portion, the second intermediate fixing portion, and the lower fixing portion are arranged in this order from top to bottom with a gap between them, and are each fixed to the support columns. The upper fixing portion has a groove on its lower surface. The first intermediate fixing portion has grooves on its upper and lower surfaces. The second intermediate fixing portion has grooves on its upper and lower surfaces. The lower fixing portion has a groove on its upper surface. The reflecting portion 16a is fixed between the upper fixing portion and the first intermediate fixing portion by having its upper end portion received in the groove on the lower surface of the upper fixing portion and its lower end portion received in the groove on the upper surface of the first intermediate fixing portion. The reflecting portion 16b is fixed between the second intermediate fixing portion and the lower fixing portion by having its lower end portion received in the groove on the upper surface of the lower fixing portion and its upper end portion received in the groove on the lower surface of the second intermediate fixing portion. The heating element 14 is disposed between the reflecting portions 16a and 16b. The heating element 14 is fixed between the first intermediate fixing portion and the second intermediate fixing portion by having its upper end portion received in the groove on the lower surface of the first intermediate fixing portion and its lower end portion received in the groove on the upper surface of the second intermediate fixing portion. The configuration for supporting the heating element 14 and the reflecting portions 16a and 16b so as to cover the heating surface 15a of the heater 15 is not limited to the above configuration.

[0035] The heat generating device 3 includes a control unit 21 electrically connected to the vacuum pump 7, the supply valve 12, the exhaust valve 13, the temperature sensor 17, and the power supply 19. The control unit 21 includes, for example, a microprocessor (MPU) that performs arithmetic processing based on application programs stored in a read-only memory (ROM) or other storage unit, and a random access memory (RAM) that temporarily stores programs and data during arithmetic processing.

[0036] The control unit 21 outputs control signals that control the operations of the vacuum pump 7, the supply valve 12, the exhaust valve 13, and the power supply 19. The vacuum pump 7, the supply valve 12, the exhaust valve 13, and the power supply 19 operate based on the control signals input from the control unit 21.

[0037] The control unit 21 closes the supply valve 12 , opens the exhaust valve 13 , and drives the vacuum pump 7 to exhaust (evacuate) the hydrogen-based gas from the space 9 inside the sealed container 5 .

[0038] The control unit 21 stops the operation of the vacuum pump 7 , closes the exhaust valve 13 , and opens the supply valve 12 , thereby supplying the hydrogen-based gas to the space 9 inside the sealed container 5 .

[0039] The control unit 21 controls the output of the power source 19 to adjust the amount of power supplied from the power source 19 to the heater 15 via the conductive wire 18 and the pair of electrodes 20. By controlling the output of the power source 19, the temperature of the heating element 14 heated by the heater 15 is adjusted, and it becomes possible to maintain the heating element 14 within an optimum temperature range for heat generation (for example, 50°C to 1500°C).

[0040] In the heat generating device 3, the hydrogen tank 6, the inlet pipe 10, and the supply valve 12 constitute a supply section that supplies a hydrogen-based gas containing hydrogen into the sealed container 5. In the heat generating device 3, the vacuum pump 7, the exhaust pipe 11, and the exhaust valve 13 constitute an exhaust section that exhausts the hydrogen-based gas from the sealed container 5.

[0041] The heat utilization device 4 includes a containment vessel 41 that stores the sealed container 5 of the heat generation device 3, a first power generation unit 42 that generates power inside the containment vessel 41 using the heat medium (helium gas in this example) heated by the heat generation device 3, a pressure pump 43 that sends the heat medium from the first power generation unit 42 toward the containment vessel 41, and a flow control valve 44 provided between the pressure pump 43 and the containment vessel 41.

[0042] The containment vessel 41 has thermal insulation and pressure resistance. It is made of, for example, stainless steel, heat-resistant non-ferrous alloy steel, or the like. A material appropriate for the operating temperature is used for the containment vessel 41. For example, stainless steel is used when the operating temperature is up to about 700°C, and heat-resistant non-ferrous alloy steel is used when the operating temperature exceeds 700°C. The containment vessel 41 has an inlet 41a through which the heat medium flows and an outlet 41b through which the heat medium flows. The heat medium that flows into the containment vessel 41 from the inlet 41a flows along the outer surface of the sealed container 5 of the heat-generating device 3 housed inside the containment vessel 41 and is heated by the heat-generating structure 8 housed in the sealed container 5. The temperature of the heat medium rises inside the containment vessel 41, and a high-temperature heat medium is obtained. The high-temperature heat medium flows out of the outlet 41b of the containment vessel 41 and flows into the first power generation unit 42.

[0043] The first power generating unit 42 includes a compressor (not shown) that compresses the high-temperature heat medium supplied from the containment vessel 41, a gas turbine 42a that is driven by the high-temperature, high-pressure heat medium compressed by the compressor, and a generator 42b connected to the gas turbine 42a. In the first power generating unit 42, the temperature of the heat medium is adjusted to, for example, a range of 600°C to 1500°C. The output shaft of the gas turbine 42a is connected to the input shaft of the generator 42b. Rotation of the turbine blades of the gas turbine 42a drives the rotor of the generator 42b, which then generates electricity (power). The heat medium whose heat has been utilized in the first power generating unit 42 flows out of the first power generating unit 42 and into the pressure pump 43.

[0044] The pressure pump 43 sends the heat medium supplied from the first power generation unit 42 at a predetermined pressure toward the containment vessel 41. The pressure pump 43 is, for example, a metal bellows pump.

[0045] The flow control valve 44 adjusts the flow rate of the heat medium flowing from the pressure pump 43 toward the containment vessel 41. As the flow control valve 44, for example, a variable leak valve is used.

[0046] Next, the configuration of the heating element 14 will be described. FIG. 2 is a cross-sectional view showing the configuration of the heating element 14. As shown in FIG. 2, the heating element 14 includes a support 61 (also referred to as a base) made of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film 62 provided on the support 61. The multilayer film 62 includes a first layer 71 made of a hydrogen storage metal or a hydrogen storage alloy and having a thickness of less than 1000 nm, and a second layer 72 made of a hydrogen storage metal, a hydrogen storage alloy, or a ceramic different from the first layer 71 and having a thickness of less than 1000 nm. Interfaces 73 of different materials are formed between the first layer 71 and the second layer 72 and between the support 61 and the multilayer film 62. The interfaces 73 of different materials allow hydrogen atoms to pass through the interfaces 73 of different materials. The heating element 14 generates excess heat by hydrogen atoms passing through the interfaces 73 of different materials by quantum diffusion, or by hydrogen atoms diffusing through the interfaces 73 of different materials by quantum diffusion. The heating elements disclosed in International Publication WO2018 / 230447, International Publication WO2020 / 122097, International Publication WO2020 / 122098, etc. can be used as the heating element 14. The detailed configuration, function, and manufacturing method of the heating element 14 are the same as those disclosed in International Publication WO2018 / 230447, International Publication WO2020 / 122097, International Publication WO2020 / 122098, etc., and therefore will not be described here.

[0047] In FIG. 2, the multilayer film 62 is configured to be laminated on one surface (e.g., the front surface) of the support 61, but this is not limited thereto, and the multilayer film 62 may be configured to be laminated on the other surface (e.g., the back surface) of the support 61, or the multilayer film 62 may be configured to be laminated on both surfaces (the front surface and the back surface) of the support 61.

[0048] Next, the heating surface 15a of the heater 15 will be described. Generally, the ends of a heater's heating surface, where radiant heat is more likely to diffuse to the surroundings, are cooler than the center. For example, in the case of a sheathed heater, the temperature distribution on the outer circumferential surface of the pipe is uniform and high in the center corresponding to the heating wire, and becomes lower toward both ends.

[0049] 3, the heating surface 15a of the heater 15 has first heating regions R1a and R1b where a first temperature distribution is generated, and a second heating region R2 where a second temperature distribution that is more uniform than the first temperature distribution is generated. Note that "uniform" includes not only strictly uniform but also approximately uniform, i.e., cases where the temperature distribution varies within the scope of the invention.

[0050] The second heat-generating region R2 constitutes the central portion of the heat-generating surface 15a. The second heat-generating region R2 is also referred to as a soaking region. The first heat-generating region R1a constitutes the upper end portion of the heat-generating surface 15a. The first temperature distribution in the first heat-generating region R1a becomes lower toward the upper end portion of the heat-generating surface 15a and becomes higher toward the central portion of the heat-generating surface 15a. The first heat-generating region R1b constitutes the lower end portion of the heat-generating surface 15a. The first temperature distribution in the first heat-generating region R1b becomes lower toward the lower end portion of the heat-generating surface 15a and becomes higher toward the central portion of the heat-generating surface 15a. In the following description, when there is no need to distinguish between the first heat-generating region R1a and the first heat-generating region R1b, they will be referred to as the first heat-generating region R1.

[0051] Of the heat-generating surface 15a that generates radiant heat, the second heat-generating region R2 is covered by the heat-generating element 14, and the first heat-generating region R1 is covered by the reflecting portion 16 (see FIG. 1). The heat-generating structure 8 has the heat-generating element 14 and the reflecting portion 16 provided to cover the heat-generating surface 15a, which makes the thermal resistance due to the radiant heat uniform, resulting in a uniform temperature distribution on the heat-generating surface 15a. The heat-generating structure 8 can make the temperature distribution of the heat-generating element 14 uniform by uniformly heating the heat-generating element 14 with the radiant heat generated from the heat-generating surface 15a, which has a uniform temperature distribution.

[0052] The operation and effects of the heating device 3 according to this embodiment will be described. First, the sealed container 5 is opened, the heating structure 8 is placed inside the sealed container 5, and the sealed container 5 is sealed. The pair of electrodes 20 of the heating structure 8 are connected to the power source 19 via the conductive wires 18. The exhaust valve 13 is opened, and the vacuum pump 7 is driven. The space 9 inside the sealed container 5 is evacuated. The operation of the vacuum pump 7 is stopped, the exhaust valve 13 is closed, and the power source 19 is driven. Power is supplied from the power source 19 to the heater 15 via the conductive wires 18 and the pair of electrodes 20. The temperature of the heating surface 15a of the heater 15 increases as a result of the power supply. The second heating region R2 constituting the center of the heating surface 15a is covered by the heating element 14, and the first heating region R1 constituting the end of the heating surface 15a is covered by the reflecting portion 16. This uniformizes the thermal resistance due to radiant heat generated from the heating surface 15a, resulting in a uniform temperature distribution on the heating surface 15a. By suppressing variations in the radiant heat transferred from the heating surface 15a to the heating element 14, the temperature distribution of the heating element 14 is made uniform. In this way, the temperature of the heating element 14 can be raised uniformly to a specific temperature. For example, by raising the temperature of the heating element 14 to about 200°C, moisture can be removed from the heating element 14.

[0053] Next, the output of the power supply 19 is increased, and the temperature of the heating element 14 further increases. For example, the temperature of the heating element 14 is set to about 300°C. The supply valve 12 is opened. Hydrogen-based gas flows from the hydrogen tank 6 into the space 9 inside the sealed container 5. The space 9 inside the sealed container 5 is filled with the hydrogen-based gas. The heating element 14 absorbs hydrogen. Specifically, a hydrogen molecule in the space 9 is adsorbed onto the surface of the multilayer film 62 of the heating element 14 (the surface opposite the support 61), and this hydrogen molecule dissociates into two hydrogen atoms. The dissociated hydrogen atoms then penetrate (absorb) into the interior of the multilayer film 62.

[0054] After hydrogen is absorbed into the heating element 14, the supply valve 12 is closed. The output of the power supply 19 is controlled to set the temperature of the heating element 14 to a desired temperature (e.g., approximately 700°C) within the optimum temperature range for heat generation. At this time, the exhaust valve 13 is opened and the vacuum pump 7 is driven. Hydrogen-based gas is exhausted from the space 9 inside the sealed container 5. The heating element 14 releases hydrogen. Specifically, hydrogen atoms that have penetrated into the interior of the multilayer film 62 return to the surface of the multilayer film 62, recombine, and are released as hydrogen molecules. As a result, the hydrogen atoms pass through the dissimilar material interface 73 by quantum diffusion, or the hydrogen atoms diffuse through the dissimilar material interface 73 by quantum diffusion, generating excess heat in the heating element 14.

[0055] In the heating structure 8, the heating surface 15a of the heater 15 has a first heating region R1 having a first temperature distribution and a second heating region R2 having a second temperature distribution that is more uniform than the first temperature distribution, the second heating region R2 being covered by the heating element 14, and the first heating region R1 being covered by the reflecting portion 16. This makes the thermal resistance due to the radiant heat generated from the heating surface 15a uniform, and the temperature distribution of the heating surface 15a becomes uniform. Therefore, in the heating structure 8, the heating element 14 is uniformly heated by the radiant heat generated from the heating surface 15a having a uniform temperature distribution, thereby making it possible to make the temperature distribution of the heating element 14 uniform.

[0056] Here, a test conducted to confirm the temperature distribution of the heating element 14 in the heating structure 8 of this embodiment and a heating structure of a comparative example will be described. The comparative example was a heating structure that did not have a reflecting portion 16. The comparative example was configured similarly to this embodiment except that it did not have a reflecting portion 16. That is, in the comparative example, the second heating region R2 was covered by the heating element 14, and the first heating region R1 was not covered by the reflecting portion 16.

[0057] 4 is a graph showing the temperature distribution of the heating element 14 in this embodiment and a comparative example. In FIG. 4, the horizontal axis represents the surface temperature of the heating element 14, and the vertical axis represents the axial length of the heating element 14, based on the lower end of the heating element 14. In this embodiment, in which the first heating region R1 is covered by the reflecting portion 16, the temperature at the end of the heating element 14 is about 80°C higher than in the comparative example in which the first heating region R1 is not covered by the reflecting portion 16, confirming that the temperature distribution of the heating element 14 is more uniform. This is thought to be due to the reflecting portion 16 being provided adjacent to the end of the heating element 14, which causes the radiant heat generated from the heating surface 15a to be reflected by the reflecting portion 16 and returned toward the end of the heating surface 15a, resulting in an increase in the temperature at the end of the heating surface 15a.

[0058] In the heating structure 8, the heater 15 is formed in a rod shape, and the heating element 14 and the reflecting portion 16 are formed in a cylindrical shape. The heating surface 15a of the heater 15 is surrounded by the heating element 14 and the reflecting portion 16. The heating structure 8 can efficiently heat the heating element 14 by radiant heat generated from the heating surface 15a. Furthermore, a general rod-shaped heater such as a sheathed heater can be used as the rod-shaped heater 15. Since general rod-shaped heaters are inexpensive, the manufacturing costs of the heating structure 8 and the heating device 3 can be reduced.

[0059] In the heating structure 8, by making the number of turns of the reflecting portion 16 equal to or greater than the number of turns of the heating element 14, the temperature distribution of the heating surface 15a becomes more uniform, and the temperature distribution of the heating element 14 can be made more uniform. The more the number of turns of the reflecting portion 16 is increased, the more the leakage of radiant heat from the end of the reflecting portion 16 (the end opposite to the side adjacent to the heating element 14) can be suppressed.

[0060] The operation and effects of the heat utilization system 1 according to this embodiment will now be described. In the piping path 2, helium gas as a heat medium flows into the containment vessel 41 by the pressure pump 43. In the containment vessel 41, heat is transferred from the heat generating device 3 to the helium gas, causing the temperature of the helium gas to rise. The high-temperature helium gas flowing out of the containment vessel 41 flows into the compressor (not shown) of the first power generation unit 42. The high-temperature, high-pressure helium gas flowing out of the compressor flows into the gas turbine 42a and rotates the turbine blades of the gas turbine 42a. The rotation of the turbine blades is transferred to the rotor of the generator 42b. Electric power is generated in the generator 42b.

[0061] The thermal energy of the helium gas is consumed to rotate the turbine blades of the gas turbine 42a. As the temperature of the helium gas decreases in the gas turbine 42a, the pressure also decreases. The helium gas flowing out of the gas turbine 42a is sucked into the pressure pump 43. The pressure pump 43 sends the helium gas toward the containment vessel 41. Power generation continues as the helium gas circulates.

[0062] As described above, the heat utilization system 1 uses, as a heat source, a heat medium heated by a heat generating device 3 equipped with a heating element 14 that generates heat by absorbing and releasing hydrogen, and therefore can supply energy cheaply, cleanly, and safely.

[0063] In the heat utilization system 1, a heating element 14 is provided around the heater 15, covering the heating surface 15a, a sealed container 5 is provided to cover the heating element 14, and a storage container 41 is provided to cover the sealed container 5, so that the heater 15 can efficiently heat the heating element 14, and the heating element 14 can efficiently heat the heat medium.

[0064] (2) Heat Utilization System According to the Second Embodiment Fig. 5 is a conceptual diagram showing the configuration of a heat utilization system 1a according to the second embodiment. The heat utilization system 1a includes a heat utilization device 4a instead of the heat utilization device 4 of the first embodiment. The heat utilization device 4a is incorporated into the piping path 2 together with the heat generating device 3. In the second embodiment, water is used as the heat medium. Note that components and members that are the same as or equivalent to those in the first embodiment are designated by the same reference numerals and will not be described again.

[0065] The heat utilization device 4a includes a boiler 101 that houses the sealed container 5 of the heat generation device 3, a second power generation unit 102 that generates power based on the gas phase heat medium supplied from the boiler 101, a condenser 103 that cools the gas phase heat medium supplied from the second power generation unit 102 to convert it into a liquid phase heat medium, and a water supply pump 104 that pressurizes the liquid phase heat medium supplied from the condenser 103 and sends it toward the boiler 101.

[0066] The boiler 101 houses a pipe 105 that functions as an evaporator. Water is supplied to the pipe 105 from a water supply pump 104. The pipe 105 is exposed to heat from the heat generating device 3. Heat is transferred from the sealed container 5 to the pipe 105. The boiler 101 generates high-temperature, high-pressure steam (gas-phase heat medium) inside the pipe 105. The high-temperature, high-pressure steam is supplied from the boiler 101 to the second power generation unit 102.

[0067] The second power generating unit 102 includes a steam turbine 102a driven by high-temperature, high-pressure steam supplied from the boiler 101, and a generator 102b connected to the steam turbine 102a. In the second power generating unit 102, the temperature of the steam is adjusted, for example, within a range of 300°C to 700°C. The output shaft of the steam turbine 102a is connected to the input shaft of the generator 102b. Rotation of the turbine blades of the steam turbine 102a drives the rotor of the generator 102b, which generates electricity. The steam after heat utilization is supplied from the second power generating unit 102 to a condenser 103.

[0068] The condenser 103 cools the steam supplied from the second power generation unit 102 using cooling water 103a to return it to water (a liquid-phase heat medium). The condenser 103 outputs low-pressure water. The low-pressure water is supplied from the condenser 103 to a feedwater pump 104. The feedwater pump 104 sends the water supplied from the condenser 103 to the boiler 101 at a predetermined pressure.

[0069] As described above, the heat utilization system 1a uses, as a heat source, a heat medium heated by a heat generating device 3 equipped with a heating element 14 that generates heat by absorbing and releasing hydrogen, and therefore can supply energy cheaply, cleanly, and safely.

[0070] Instead of water, the heat medium may be a substance that changes from a liquid phase to a gas phase in response to the heat of the heat generating device 3. It is preferable to use a substance that has excellent thermal conductivity and is chemically stable as the heat medium.

[0071] (3) Heat Utilization System According to the Third Embodiment Figure 6 is a conceptual diagram showing the configuration of a heat utilization system 1b according to the third embodiment. The heat utilization system 1b includes a heat utilization device 4b instead of the heat utilization device 4 of the first embodiment. The heat utilization device 4b includes a Stirling engine 110 that receives heat from the heat-generating device 3 to drive it, and a generator 111 connected to the Stirling engine 110. Note that components and members that are the same as or equivalent to those in the above embodiments are designated by the same reference numerals, and descriptions thereof will be omitted.

[0072] The Stirling engine 110 includes a first cylinder 112 having a closed end at one end, an expansion piston 114 housed in the first cylinder 112 at a position facing the closed end and defining an expansion chamber 113 between itself and the closed end, a second cylinder 115 having a closed end at one end, a compression piston 117 housed in the second cylinder 115 at a position facing the closed end and defining a compression chamber 116 between itself and the closed end, a heater 118 connecting the expansion chamber 113 and the compression chamber 116 and receiving thermal energy from the sealed container 5 of the heat generating device 3, a cooler 119 disposed between the compression chamber 116 and the heater 118, a regenerator 120 disposed between the cooler 119 and the heater 118, and a crankshaft 122 as an output shaft connected to the expansion piston 114 and the compression piston 117 individually by connecting rods 121 a and 121 b.

[0073] A crankshaft 122 (output shaft) of the Stirling engine 110 is connected to an input shaft of the generator 111. When the crankshaft 122 rotates, the rotor of the generator 111 is driven, and the generator 111 generates electricity.

[0074] The expansion piston 114 is displaced within the first cylinder 112 along the axial direction of the first cylinder 112. When the expansion piston 114 moves away from the closed end of the first cylinder 112, the expansion chamber 113 expands. When the expansion piston 114 approaches the closed end of the first cylinder 112, the expansion chamber 113 contracts. The axial reciprocating motion of the expansion piston 114 is converted into rotational motion of the crankshaft 122. A working fluid is sealed in the expansion chamber 113. Here, helium gas is used as the working fluid. In addition to helium gas, a hydrogen-based gas or air may also be used as the working fluid.

[0075] The compression piston 117 is displaced within the second cylinder 115 along the axial direction of the second cylinder 115. When the compression piston 117 moves away from the closed end of the second cylinder 115, the compression chamber 116 expands. When the compression piston 117 approaches the closed end of the second cylinder 115, the compression chamber 116 contracts. The rotational motion of the crankshaft 122 is converted into axial reciprocating motion of the compression piston 117. Because the compression chamber 116 is connected to the expansion chamber 113, the compression chamber 116 is filled with working fluid in the same way as the expansion chamber 113. The working fluid travels between the expansion chamber 113 and the compression chamber 116 via a heater 118, a regenerator 120, and a cooler 119.

[0076] The heater 118 transfers heat from the sealed container 5 to the working fluid. The working fluid is heated by the heat-generating structure 8 housed in the sealed container 5 and flows into the expansion chamber 113. The expansion chamber 113 expands in response to the expansion of the working fluid. The expansion piston 114 is displaced toward the crankshaft 122. The high-temperature, high-pressure working fluid flows from the heater 118 into the regenerator 120 in response to the contraction of the expansion chamber 113.

[0077] The cooler 119 cools the working fluid using a cooling medium (not shown). The cooling medium is, for example, water. The working fluid is cooled by the cooling medium and flows into the compression chamber 116. The compression chamber 116 expands. The compression piston 117 is displaced toward the crankshaft 122. As the compression chamber 116 contracts, the low-temperature, low-pressure working fluid flows from the regenerator 120 into the heater 118.

[0078] The regenerator 120 absorbs and stores thermal energy from the working fluid flowing in from the heater 118, and transfers the stored thermal energy to the working fluid flowing in from the cooler 119. Therefore, the working fluid in the expansion chamber 113 releases thermal energy in the regenerator 120 before flowing into the cooler 119. The working fluid in the compression chamber 116 is heated in the regenerator 120 before flowing into the heater 118.

[0079] As described above, the heat utilization system 1b uses, as a heat source, a heat medium heated by a heat generating device 3 equipped with a heating element 14 that generates heat by absorbing and releasing hydrogen, and therefore can supply energy cheaply, cleanly, and safely.

[0080] (4) Heat Utilization System According to the Fourth Embodiment Fig. 7 is a conceptual diagram showing the general configuration of a heat utilization system 1c according to the fourth embodiment. The heat utilization system 1c includes a heat utilization device 4c instead of the heat utilization device 4 of the first embodiment. The heat utilization device 4c includes a thermoelectric converter 130 that generates electricity based on a temperature difference. Note that components and members that are the same as or equivalent to those in the above embodiments are designated by the same reference numerals and will not be described again.

[0081] The thermoelectric converter 130 has a heat receiving plate 131 and a heat dissipation plate 132. A high-temperature pipe 133 is in contact with the heat receiving plate 131. The high-temperature pipe 133 is connected to the pipe path 2 and allows a heat medium to flow through it. A low-temperature pipe 134 is in contact with the heat dissipation plate 132. The low-temperature pipe 134 allows cooling water to flow through it.

[0082] The thermoelectric converter 130 is sandwiched between a heat receiving plate 131 and a heat dissipation plate 132, and includes a p-type semiconductor 135a and an n-type semiconductor 135b arranged in parallel between the heat receiving plate 131 and the heat dissipation plate 132. The p-type semiconductor 135a and the n-type semiconductor 135b are electrically connected in series alternately based on a first electrode fixed to the heat receiving plate 131 and a second electrode fixed to the heat dissipation plate 132. Electric power is extracted from the second electrodes located at both ends of the series connection.

[0083] As described above, the heat utilization system 1c uses, as a heat source, a heat medium heated by a heat generating device 3 equipped with a heating element 14 that generates heat by absorbing and releasing hydrogen, and therefore can supply energy cheaply, cleanly, and safely.

[0084] (5) Heat Utilization System According to the Fifth Embodiment Figure 8 is a conceptual diagram showing the configuration of a heat utilization system 1d according to the fifth embodiment. The heat utilization system 1d includes a heat generation device 3a instead of the heat generation device 3 of the first embodiment. The heat generation device 3a is incorporated into the piping path 2 together with a heat utilization device 4. Note that components and members that are the same as or equivalent to those of the first embodiment are designated by the same reference numerals and will not be described again.

[0085] The heat generating device 3a includes a heat generating structure 8a instead of the heat generating structure 8 of the first embodiment. The heat generating structure 8a heats the heat medium flowing along the outer surface of the sealed container 5 through the sealed container 5. The temperature of the heat medium heated by the heat generating structure 8a reaches a range of, for example, 50°C to 1500°C. In this example, the temperature of the heat medium is set to 700°C.

[0086] The heating structure 8a includes a heating element 14a instead of the heating element 14 of the first embodiment, and further includes a reflector 205 (also referred to as a reflector) that reflects heat generated from the heating element 14a. That is, the heating structure 8a includes the heating element 14a that generates heat by absorbing and releasing hydrogen, a heater 15 that has a heating surface 15a (also referred to as a heater heating surface) that generates radiant heat and heats the heating element 14a with radiant heat, reflectors 16a and 16b that are provided adjacent to the heating element 14a and reflect the radiant heat, a temperature sensor 17 that detects the temperature of the heating element 14a, and a reflector 205 that is provided adjacent to the heating element 14a and reflects the heat generated from the heating element 14a.

[0087] Fig. 9 is a perspective view of a heat generating structure 8a according to a fifth embodiment. Fig. 10 is a cross-sectional view taken along line X-X shown in Fig. 9. As shown in Figs. 9 and 10, the heat generating structure 8a has a configuration in which one heat generating element 14a is wound around a heater 15. The number of heat generating elements 14a is not particularly limited as long as it is one or more.

[0088] The heating element 14a is formed in a cylindrical shape. In this embodiment, the heating element 14a is formed in a cylindrical shape. The cross-sectional shape of the heating element 14a is spiral. That is, the heating element 14a has a configuration in which a multilayer film 62 (see FIG. 2) is formed on the surface of a support 61 (see FIG. 2) having a spiral cross-section whose diameter increases toward the outer periphery. The number of turns of the heating element 14a is two in this example, but may be three or more. The axial length of the heating element 14a is 300 mm in this example, but is not particularly limited. The circumferential length of the heating element 14a is 100 mm in this example, but is not particularly limited. The thickness of the heating element 14a is 0.1 mm in this example, but is not particularly limited. The heating element 14a is not limited to a cylindrical shape and may have other appropriate shapes, such as an elliptical cylindrical shape or a polygonal cylindrical shape. When the heating element 14a is elliptical cylindrical, the diameter of the heating element 14a refers to the major axis. When the heating element 14a is a polygonal cylindrical shape, the diameter of the heating element 14a means the diameter of the circumscribed circle. Note that the spiral shape means a shape in which the diameter gradually increases from one end to the other end, and includes a shape with one turn as well as a shape with two or more turns.

[0089] The heating element 14a has an inner peripheral portion 200 and an outer peripheral portion 201. The inner peripheral portion 200 is the radially innermost portion (also referred to as the innermost layer) of the heating element 14a, and is the first turn in this embodiment. The outer peripheral portion 201 is the radially outermost portion (also referred to as the outermost layer) of the heating element 14a, and is the second turn in this embodiment. The outer peripheral portion 201 is covered with a reflector 205.

[0090] The heater 15 is configured similarly to the first embodiment. The heater 15 is formed in a rod shape. The heating surface 15a of the heater 15 is surrounded by the heating element 14a and reflecting portions 16a and 16b. The heating surface 15a has first heating regions R1a and R1b where a first temperature distribution occurs, and a second heating region R2 where a second temperature distribution more uniform than the first temperature distribution occurs. The first heating region R1a forms the upper end of the heating surface 15a and is covered by the reflecting portion 16a. The first heating region R1b forms the lower end of the heating surface 15a and is covered by the reflecting portion 16b. The second heating region R2 forms the center of the heating surface 15a and is covered by the heating element 14a.

[0091] The reflecting portions 16a and 16b are provided adjacent to the axial ends of the heating element 14a. Specifically, the reflecting portion 16a is provided adjacent to the upper axial end of the heating element 14a (i.e., the upper end of the heating element 14a), and the reflecting portion 16b is provided adjacent to the lower axial end of the heating element 14a (i.e., the lower end of the heating element 14a).

[0092] The reflective portions 16a and 16b have the same configuration. The reflective portions 16 (16a, 16b) are formed in a cylindrical shape. In this embodiment, the reflective portion 16 is formed in a cylindrical shape. The cross-sectional shape of the reflective portion 16 is spiral. That is, the reflective portion 16 is wound around the heater 15, and has a spiral cross-section with a diameter that increases toward the outer periphery. The number of turns of the reflective portion 16 is two in this example, but may be three or more. The number of turns of the reflective portion 16 is preferably equal to or greater than the number of turns of the heating element 14a. In this example, the axial length of each reflective portion 16 is 70 mm, but is not particularly limited. The reflective portion 16 is not limited to a cylindrical shape and may have other appropriate shapes, such as an elliptical cylindrical shape or a polygonal cylindrical shape. When the reflective portion 16 is an elliptical cylindrical shape, the diameter of the reflective portion 16 refers to the major axis. When the reflective portion 16 is a polygonal cylindrical shape, the diameter of the reflective portion 16 refers to the diameter of the circumscribed circle.

[0093] The temperature sensor 17 outputs a detection signal that specifies the detected temperature. The temperature sensor 17 has, for example, a thermocouple embedded in the heating element 14a.

[0094] The reflector 205 is disposed adjacent to the outer periphery 201 of the heating element 14a in the radial direction. The reflector 205 is formed in a cylindrical shape. In this embodiment, the reflector 205 is formed in a cylindrical shape. The cross-sectional shape of the reflector 205 is spiral. That is, the reflector 205 is wound around the heater 15, and has a spiral cross-section with a diameter that increases toward the outer periphery. The number of turns of the reflector 205 is one in this example, but may be two or more. The axial length of the reflector 205 is preferably equal to or greater than the axial length of the heating element 14a (300 mm in this example). The circumferential length of the reflector 205 is 50 mm in this example, but is not particularly limited. The thickness of the reflector 205 is 0.1 mm in this example, but is not particularly limited. The reflector 205 is not limited to a cylindrical shape, and may have other appropriate shapes, such as an elliptical cylindrical shape or a polygonal cylindrical shape. When the reflector 205 has an elliptical cylindrical shape, the diameter of the reflector 205 means the major axis. When the reflector 205 has a polygonal cylindrical shape, the diameter of the reflector 205 means the diameter of the circumscribing circle.

[0095] The reflector 205 is formed of a low-emissivity material. Examples of low-emissivity materials include metals such as Ni, Mo, Cu, Au, Pd, Fe, Co, Pt, Os, Cr, V, Ti, and W, and alloys thereof. Examples of alloys include stainless steel such as SUS304 and nickel-based alloys such as NCF600. The reflector 205 is preferably formed of a material that has low emissivity and is heat-resistant and pressure-resistant. The low-emissivity material constituting the reflector 205 may be the same material as the reflective portions 16a and 16b. In this example, Ni foil made of Ni is used as the reflector 205. The reflector 205 may also be configured by providing a reflective film made of a low-emissivity material on the surface of a heat-resistant and pressure-resistant substrate, for example, by plating.

[0096] The reflector 205 reflects heat (radiant heat) generated from the radially outer peripheral portion 201 of the heating element 14a and returns it to the outer peripheral portion 201. The temperature of the radially outer peripheral portion 201 of the heating element 14a increases due to the heat (radiant heat) reflected by the reflector 205. As a result, the temperature difference between the inner peripheral portion 200 of the heating element 14a, which receives the radiant heat from the heater 15, and the outer peripheral portion 201, which receives the heat reflected by the reflector 205, is reduced. As a result, the temperature distribution in the radial direction of the heating element 14a becomes uniform. Note that if a reflector is not provided, the temperature difference between the radially inner peripheral portion and the radially outer peripheral portion of the heating element becomes large, making it difficult to maintain the temperature of the radially outer peripheral portion of the heating element at an optimal temperature for heat generation (also referred to as the heating temperature). If the temperature distribution in the radial direction of the heating element is uneven, the heating efficiency of the heating element decreases.

[0097] The heating structure 8a includes heat-conducting portions 210 (also referred to as pillars) provided between an inner peripheral portion 200 and an outer peripheral portion 201 in the radial direction of the heating element 14a and between the outer peripheral portion 201 in the radial direction of the heating element 14a and a reflector 205. The heat-conducting portions 210 are in contact with the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a, and are also in contact with the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205.

[0098] The heat conducting portions 210 are formed of linear bodies extending along the circumferential direction of the heating element 14a. The number of heat conducting portions 210 is not particularly limited. FIG. 10 illustrates five heat conducting portions 210 arranged at intervals along the axial direction of the heating element 14a. The five heat conducting portions 210 have the same configuration. The interval between adjacent heat conducting portions 210 among the five heat conducting portions 210 is not particularly limited. In this example, the five heat conducting portions 210 are arranged at equal intervals. The heat conducting portions 210 are not limited to being formed of linear bodies extending along the circumferential direction of the heating element 14a, but may also be formed of linear bodies extending along the axial direction of the heating element 14a. In this case, multiple heat conducting portions 210 may be arranged at intervals along the circumferential direction of the heating element 14a.

[0099] The heat conducting portion 210 is made of a material that does not inhibit the heat generation of the heating element 14a. Examples of materials that do not inhibit the heat generation of the heating element 14a include Ni, Au, Pt, and Ti. The heat conducting portion 210 may be made of the same material as the support 61 (see FIG. 2) or the multilayer film 62 (see FIG. 2) that constitutes the heating element 14a.

[0100] The heat conducting portion 210 is formed in a cylindrical shape. In this embodiment, the heat conducting portion 210 is formed in a cylindrical shape. The cross-sectional shape of the heat conducting portion 210 is spiral. That is, the heat conducting portion 210 is wound around the heater 15, and has a spiral cross-section with a diameter that increases toward the outer periphery. The number of turns of the heat conducting portion 210 is set based on the number of turns of the heating element 14a and the number of turns of the reflector 205. In this embodiment, the number of turns of the heating element 14a is two and the number of turns of the reflector 205 is one, so the number of turns of the heat conducting portion 210 is three. The axial length of the heat conducting portion 210 (also referred to as the width of the heat conducting portion 210) is preferably less than the axial length of the heating element 14a. In this example, the axial length of the heat conducting portion 210 is 5 mm, but is not particularly limited. In this example, the thickness of the heat conducting portion 210 is 1 mm, but is not particularly limited. The heat conducting part 210 is not limited to a cylindrical shape, and may have any other appropriate shape, such as an elliptical cylindrical shape, a polygonal cylindrical shape, etc. When the heat conducting part 210 has an elliptical cylindrical shape, the diameter of the heat conducting part 210 means the major axis. When the heat conducting part 210 has a polygonal cylindrical shape, the diameter of the heat conducting part 210 means the diameter of the circumscribed circle.

[0101] The heat conducting portions 210 form heat conducting paths extending along the radial direction of the heat generating element 14a. In this embodiment, five heat conducting paths are formed by five heat conducting portions 210. In Fig. 10, the topmost heat conducting path of the five heat conducting paths is indicated by a bold white arrow.

[0102] The heat conduction path formed by the heat conduction portion 210 transfers heat by thermal conduction between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a, and also transfers heat by thermal conduction between the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205. The heat conduction paths between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a and between the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205 allow heat to be efficiently dissipated from the inner peripheral portion 200 in the radial direction of the heating element 14a via the outer peripheral portion 201 to the reflector 205, thereby reducing the temperature difference between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform.

[0103] In this embodiment, the heat conductive portion 210 is provided between the radial inner circumferential portion 200 and the radial outer circumferential portion 201 of the heating element 14a, between the radial outer circumferential portion 201 of the heating element 14a and the reflector 205, and also between the heater 15 and the radial inner circumferential portion 200 of the heating element 14a. The heat conductive portion 210 is in contact with the heater 15 and the radial inner circumferential portion 200 of the heating element 14a. The heat conductive path formed by the heat conductive portion 210 transfers heat by thermal conduction between the heater 15 and the radial inner circumferential portion 200 of the heating element 14a. Heat from the heater 15 is transferred to the heating element 14a by radiation and also by thermal conduction via the heat conductive path. The heat conductive path between the heater 15 and the radial inner circumferential portion 200 of the heating element 14a allows the heating element 14a to be efficiently heated.

[0104] The thermally conductive portion 210 functions as a spacer that forms a space between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction and between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205. The spaces formed between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction and between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205 serve as flow paths through which the hydrogen-based gas flows. The hydrogen-based gas can be efficiently brought into contact with the heating element 14a by flowing through the flow paths. The hydrogen contained in the hydrogen-based gas can be efficiently occluded by the heating element 14a, thereby promoting heat generation in the heating element 14a.

[0105] In the heat generating structure 8a, the heater 15 is formed in a rod shape, and the heat generating element 14a, the reflecting portion 16, the reflector 205, and the heat conducting portion 210 are formed in a cylindrical shape. The heat generating surface 15a of the heater 15 is surrounded by the heat generating element 14a and the reflecting portion 16. The axial directions of the heat generating element 14a, the heater 15, the reflecting portion 16, the reflector 205, and the heat conducting portion 210 are aligned with one another.

[0106] An example of a manufacturing method of the heat generating structure 8a will be described with reference to Figures 11 and 12. First, as shown in Figure 11, a heat conducting portion 210 is placed on the heat generating element 14a, a heater 15 is placed on the heat conducting portion 210, and the heat conducting portion 210 and the heat generating element 14a are wrapped around the heater 15. Next, as shown in Figure 12, the heat conducting portion 210 is placed on the reflector 205, the heat generating element 14a wrapped around the heater 15 is placed on the heat conducting portion 210, and the reflector 205 and the heat conducting portion 210 are wrapped around the heat generating element 14a. In this way, the heat conducting portions 210 can be placed between the heater 15 and the radial inner periphery 200 of the heat generating element 14a, between the radial inner periphery 200 and the outer periphery 201 of the heat generating element 14a, and between the radial outer periphery 201 of the heat generating element 14a and the reflector 205. The heating structure 8a is manufactured by wrapping the reflecting portion 16a around the heater 15 so that it is adjacent to the upper end of the heating element 14a, and wrapping the reflecting portion 16b around the heater 15 so that it is adjacent to the lower end of the heating element 14a (see Figure 10).

[0107] The heating structure 8a includes a heating element 14a having a spiral cross section with a diameter increasing toward the outer periphery, and a reflector 205 provided adjacent to the radial outer periphery 201 of the heating element 14a. Heat generated from the radial outer periphery 201 of the heating element 14a is reflected by the reflector 205 and returned toward the radial outer periphery 201 of the heating element 14a. This increases the temperature of the radial outer periphery 201 of the heating element 14a, reducing the temperature difference between the radial inner periphery 200 and outer periphery 201 of the heating element 14a. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform. Therefore, the heating structure 8a can make the temperature distribution of the heating element 14a more uniform.

[0108] The heating structure 8a includes heat-conducting portions 210 provided between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction and between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205. The heat-conducting portions 210 form heat-conducting paths extending along the radial direction of the heating element 14a. The heat-conducting paths formed by the heat-conducting portions 210 transfer heat by thermal conduction between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction, and transfer heat by thermal conduction between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205. Heat can be efficiently dissipated from the inner peripheral portion 200 of the heating element 14a via the outer peripheral portion 201 to the reflector 205, thereby reducing the temperature difference between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform. Therefore, the heat generating structure 8a can make the temperature distribution of the heat generating element 14a more uniform.

[0109] In the heating structure 8a, of the heating surface 15a of the heater 15, the first heating region R1a is covered by the reflecting portion 16a, the first heating region R1b is covered by the reflecting portion 16b, and the second heating region R2 is covered by the heating element 14a. This homogenizes the thermal resistance due to the radiant heat generated from the heating surface 15a, resulting in a uniform temperature distribution on the heating surface 15a. The heating element 14a is heated by the radiant heat generated from the heating surface 15a, which has a uniform temperature distribution, so that the temperature distribution in the axial direction of the heating element 14a becomes more uniform. Therefore, the heating structure 8a can more homogenize the temperature distribution of the heating element 14a.

[0110] In this embodiment, the heating element 14a has a configuration in which a multilayer film 62 (see FIG. 2) is formed on the surface of a support 61 (see FIG. 2) having a spiral cross section with a diameter increasing toward the outer periphery. However, the present invention is not limited to this configuration, and the multilayer film 62 may be formed on the surface of multiple cylindrical supports 61 having different diameters spaced apart in the radial direction. In this case, too, the reflector 205 provided adjacent to the radial outer periphery 201 of the heating element 14a reduces the temperature difference between the radial inner periphery 200 and the radial outer periphery 201 of the heating element 14a. This results in a more uniform temperature distribution in the radial direction of the heating element 14a. Therefore, the heating structure 8a can more uniformly distribute the temperature of the heating element 14a.

[0111] The heat utilization system 1d may include, instead of the heat utilization device 4, the heat utilization device 4a of the second embodiment, the heat utilization device 4b of the third embodiment, or the heat utilization device 4c of the fourth embodiment.

[0112] (6) Heat Utilization System According to the Sixth Embodiment Fig. 13 is a conceptual diagram showing the configuration of a heat utilization system 1e according to the sixth embodiment. The heat utilization system 1e includes a heat generation device 3b instead of the heat generation device 3a of the fifth embodiment. The heat generation device 3b is incorporated into the piping path 2 together with the heat utilization device 4. Note that components and members that are the same as or equivalent to those of the fifth embodiment are given the same reference numerals and will not be described again.

[0113] The heat generating device 3b includes a heat generating structure 8b instead of the heat generating structure 8a of the fifth embodiment. The heat generating structure 8b heats the heat medium flowing along the outer surface of the sealed container 5 through the sealed container 5. The temperature of the heat medium heated by the heat generating structure 8b reaches a range of, for example, 50°C to 1500°C. In this example, the temperature of the heat medium is set to 700°C.

[0114] The heating structure 8b includes a heating element 14a that generates heat by absorbing and releasing hydrogen, a heater 15 that has a heating surface 15a (heater heating surface) that generates radiant heat and heats the heating element 14a with radiant heat, a temperature sensor 17 that detects the temperature of the heating element 14a, and a reflector 205 that is provided adjacent to the heating element 14a and reflects the heat generated from the heating element 14a.

[0115] FIG. 14 is a perspective view of a heat generating structure 8b according to the sixth embodiment. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14. As shown in FIGS. 14 and 15, the heat generating structure 8b has a configuration in which four heat generating elements 14a are wound around a heater 15. The four heat generating elements 14a are arranged at intervals along the axial direction of the heater 15. The four heat generating elements 14a have the same configuration. The distance between adjacent heat generating elements 14a among the four heat generating elements 14a is not particularly limited. In this example, the distance between the first and second heat generating elements 14a from the bottom is smaller than the distance between the second and third heat generating elements 14a from the bottom, and is the same as the distance between the third and fourth heat generating elements 14a from the bottom. The number of heat generating elements 14a is not particularly limited, as long as it is one or more.

[0116] The heating element 14a is formed in a cylindrical shape. In this embodiment, the heating element 14a is formed in a cylindrical shape. The cross-sectional shape of the heating element 14a is spiral. That is, the heating element 14a has a configuration in which a multilayer film 62 (see FIG. 2) is formed on the surface of a support 61 (see FIG. 2) having a spiral cross-section whose diameter increases toward the outer periphery. The number of turns of the heating element 14a is two in this example, but may be three or more. The axial length of the heating element 14a is 50 mm in this example, but is not particularly limited. The circumferential length of the heating element 14a is 100 mm in this example, but is not particularly limited. The thickness of the heating element 14a is 0.1 mm in this example, but is not particularly limited. The heating element 14a is not limited to a cylindrical shape, and may have other appropriate shapes, such as an elliptical cylindrical shape or a polygonal cylindrical shape.

[0117] The heating element 14a has an inner peripheral portion 200 and an outer peripheral portion 201. The inner peripheral portion 200 is the radially innermost portion (innermost layer) of the heating element 14a, and is the first turn in this embodiment. The outer peripheral portion 201 is the radially outermost portion (outermost layer) of the heating element 14a, and is the second turn in this embodiment. The outer peripheral portion 201 is covered with a reflector 205.

[0118] The heater 15 is formed in a rod shape. In this embodiment, the outer peripheral surface of the heater 15 is a cylindrical surface. The outer peripheral surface of the heater 15 is not limited to a cylindrical surface, and may be an elliptical cylindrical surface, a rectangular cylindrical surface, or the like. As the rod-shaped heater 15, a sheathed heater, a ceramic heater, a lamp heater, or the like is used. In this embodiment, a lamp heater is used as the heater 15. For example, a lamp heater has a configuration in which a tungsten filament is housed in a quartz tube.

[0119] The heating surface 15a of the heater 15 constitutes the outer peripheral surface of the heater 15 except for the portions extending a predetermined distance from both ends in the axial direction of the heater 15. Therefore, in this embodiment, the heating surface 15a is a cylindrical surface.

[0120] The heater 15 has a pair of electrode portions 20 (see FIG. 13 ). The pair of electrode portions 20 are connected to conductive wires 18. The conductive wires 18 are connected to a power source 19, electrically connecting the pair of electrode portions 20 and the power source 19. The heater 15 receives power from the power source 19 via the conductive wires 18 and the pair of electrode portions 20, thereby increasing the temperature of the heating surface 15 a. The heater 15 heats the heating element 14 a by radiant heat generated from the heating surface 15 a. Although the pair of electrode portions 20 are provided at both ends of the heater 15 in FIG. 13 , they may be provided at one or the other end of the heater 15. Although the pair of electrode portions 20 extend from the inside to the outside of the sealed container 5 in FIG. 13 , they may be housed inside the sealed container 5.

[0121] The heating surface 15a of the heater 15 has first heating regions R1a and R1b where a first temperature distribution occurs, and a second heating region R2 where a second temperature distribution that is more uniform than the first temperature distribution occurs. The first heating region R1a constitutes the upper end of the heating surface 15a. The first heating region R1b constitutes the lower end of the heating surface 15a. The second heating region R2 constitutes the center of the heating surface 15a.

[0122] Of the heat-generating surface 15a that generates radiant heat, the second heat-generating region R2 is covered by the heat-generating element 14a. In the heat-generating structure 8b, the heat-generating element 14a is provided so as to cover the second heat-generating region R2 of the heat-generating surface 15a, so that the temperature distribution in the axial direction of the heat-generating element 14a can be made more uniform than in the case where the heat-generating element 14a is provided so as to cover the entire heat-generating surface 15a.

[0123] The temperature sensor 17 outputs a detection signal that specifies the detected temperature. The temperature sensor 17 includes, for example, a thermocouple embedded in the heating element 14a. In this embodiment, a temperature sensor 17 is provided for each of the four heating elements 14a. However, in consideration of visibility in the drawings, only the temperature sensor 17 provided for the fourth heating element 14a from the bottom is shown in Figs. 13 and 14, and the temperature sensors 17 provided for the other three heating elements 14a are omitted.

[0124] The reflector 205 is disposed adjacent to the outer periphery 201 of the heating element 14a in the radial direction. The reflector 205 is formed in a cylindrical shape. In this embodiment, the reflector 205 is formed in a cylindrical shape. The cross-sectional shape of the reflector 205 is spiral. That is, the reflector 205 is wound around the heater 15, and has a spiral cross-section with a diameter that increases toward the outer periphery. The number of turns of the reflector 205 is one in this example, but may be two or more. The axial length of the reflector 205 is preferably equal to or greater than the axial length of the heating element 14a (50 mm in this example). The circumferential length of the reflector 205 is 50 mm in this example, but is not particularly limited thereto. The thickness of the reflector 205 is 0.1 mm in this example, but is not particularly limited thereto. The reflector 205 is not limited to a cylindrical shape, and may have other appropriate shapes, such as an elliptical cylindrical shape or a polygonal cylindrical shape. 13, 14 and 15, the reflector 205 is divided into four parts in the axial direction, but the reflector 205 may be one piece.

[0125] The reflector 205 is formed of a low-emissivity material. Examples of low-emissivity materials include metals such as Ni, Mo, Cu, Au, Pd, Fe, Co, Pt, Os, Cr, V, Ti, and W, and alloys thereof. Examples of alloys include stainless steel such as SUS304 and nickel-based alloys such as NCF600. The reflector 205 is preferably formed of a material that has low emissivity and is heat-resistant and pressure-resistant. In this example, Ni foil made of Ni is used as the reflector 205. The reflector 205 may also be configured by providing a reflective film made of a low-emissivity material on the surface of a heat-resistant and pressure-resistant base material, for example, by plating.

[0126] The reflector 205 reflects heat (radiant heat) generated from the radially outer peripheral portion 201 of the heating element 14a and returns it to the outer peripheral portion 201. The temperature of the radially outer peripheral portion 201 of the heating element 14a increases due to the heat (radiant heat) reflected by the reflector 205. This reduces the temperature difference between the inner peripheral portion 200 of the heating element 14a, which receives the radiant heat from the heater 15, and the outer peripheral portion 201, which receives the heat reflected by the reflector 205. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform. Note that if the radially outer peripheral portion of the heating element is not covered by a reflector, the temperature difference between the radially inner and outer peripheral portions of the heating element becomes large, making it difficult to maintain the inner peripheral portion of the heating element at the heating temperature (the temperature optimal for heating) while allowing the outer peripheral portion of the heating element to reach the heating temperature. When attempting to allow the outer peripheral portion of the heating element to reach the heating temperature, the temperature of the inner peripheral portion of the heating element may reach the melting point of the heating element, resulting in damage. Conventional heating devices can efficiently heat the radially inner periphery of the heating element by radiant heat generated from the outer periphery of the cylindrical heater. However, in conventional heating devices, a large temperature difference occurs between the radially inner periphery of the heating element, which is more susceptible to radiant heat from the heater, and the radially outer periphery of the heating element, which is less susceptible to radiant heat from the heater. This can result in uneven temperature distribution in the radial direction of the heating element, potentially reducing heating efficiency. In particular, increasing the number of windings or layers of the heating element to increase the size of the heating device tends to increase the temperature difference between the radially inner and outer peripheries of the heating element. In this embodiment, the radially outer periphery 201 of the heating element 14a is covered by the reflector 205, thereby reducing the temperature difference between the radially inner periphery 200 and outer periphery 201 of the heating element 14a and making the temperature distribution in the radial direction of the heating element 14a more uniform.

[0127] The heating structure 8b includes a plurality of heat-conducting portions 210 (pillars) provided between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a and between the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205. The heat-conducting portions 210 are in contact with the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a, and are also in contact with the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205.

[0128] The heat conducting portions 210 are formed of linear elements extending along the circumferential direction of the heating element 14a. The number of heat conducting portions 210 is not particularly limited. In FIG. 15 , three heat conducting portions 210 are illustrated for one heating element 14a, spaced apart along the axial direction of the heating element 14a. The three heat conducting portions 210 have the same configuration. In this example, the spacing between adjacent heat conducting portions 210 is equal, but is not particularly limited. The heat conducting portions 210 are not limited to being formed of linear elements extending along the circumferential direction of the heating element 14a, but may also be formed of linear elements extending along the axial direction of the heating element 14a. In this case, multiple heat conducting portions 210 may be arranged at intervals along the circumferential direction of the heating element 14a.

[0129] The heat conducting portion 210 is made of a material that does not inhibit the heat generation of the heating element 14a. Examples of materials that do not inhibit the heat generation of the heating element 14a include Ni, Au, Pt, and Ti. The heat conducting portion 210 may be made of the same material as the support 61 (see FIG. 2) or the multilayer film 62 (see FIG. 2) that constitutes the heating element 14a.

[0130] The heat conducting portion 210 is formed in a cylindrical shape. In this embodiment, the heat conducting portion 210 is formed in a cylindrical shape. The cross-sectional shape of the heat conducting portion 210 is spiral. That is, the heat conducting portion 210 is wound around the heater 15, and has a spiral cross-section with a diameter that increases toward the outer periphery. The number of turns of the heat conducting portion 210 is set based on the number of turns of the heating element 14a and the number of turns of the reflector 205. In this embodiment, the number of turns of the heating element 14a is two and the number of turns of the reflector 205 is one, so the number of turns of the heat conducting portion 210 is three. The axial length of the heat conducting portion 210 (also referred to as the width of the heat conducting portion 210) is preferably less than the axial length of the heating element 14a. In this example, the axial length of the heat conducting portion 210 is 5 mm, but is not particularly limited. In this example, the thickness of the heat conducting portion 210 is 1 mm, but is not particularly limited. The heat conduction portion 210 is not limited to a cylindrical shape, and may have any other appropriate shape, such as an elliptical cylindrical shape, a polygonal cylindrical shape, etc. Although the reflector 205 is divided into four parts in the axial direction in Figures 13, 14, and 15, the reflector 205 may be an integrated unit.

[0131] The heat conducting portions 210 form heat conduction paths extending along the radial direction of the heat generating element 14a. In this embodiment, three heat conducting paths are formed for one heat generating element 14a by three heat conducting portions 210. In Fig. 15, the topmost heat conducting path of the three heat conducting paths for the topmost heat generating element 14a of the four heat generating elements 14a is indicated by a thick white arrow.

[0132] The heat conduction path formed by the heat conduction portion 210 transfers heat by thermal conduction between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a, and also transfers heat by thermal conduction between the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205. The heat conduction paths between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a and between the outer peripheral portion 201 in the radial direction of the heating element 14a and the reflector 205 allow heat to be efficiently dissipated from the inner peripheral portion 200 in the radial direction of the heating element 14a via the outer peripheral portion 201 to the reflector 205, thereby reducing the temperature difference between the inner peripheral portion 200 and the outer peripheral portion 201 in the radial direction of the heating element 14a. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform.

[0133] In this embodiment, the heat conductive portion 210 is provided between the radial inner circumferential portion 200 and the radial outer circumferential portion 201 of the heating element 14a, between the radial outer circumferential portion 201 of the heating element 14a and the reflector 205, and also between the heater 15 and the radial inner circumferential portion 200 of the heating element 14a. The heat conductive portion 210 is in contact with the heater 15 and the radial inner circumferential portion 200 of the heating element 14a. The heat conductive path formed by the heat conductive portion 210 transfers heat by thermal conduction between the heater 15 and the radial inner circumferential portion 200 of the heating element 14a. Heat from the heater 15 is transferred to the heating element 14a by radiation and also by thermal conduction via the heat conductive path. The heat conductive path between the heater 15 and the radial inner circumferential portion 200 of the heating element 14a allows the heating element 14a to be efficiently heated.

[0134] The thermally conductive portion 210 functions as a spacer that forms a space between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction and between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205. The spaces formed between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction and between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205 serve as flow paths through which the hydrogen-based gas flows. The hydrogen-based gas can be efficiently brought into contact with the heating element 14a by flowing through the flow paths. The hydrogen contained in the hydrogen-based gas can be efficiently occluded by the heating element 14a, thereby promoting heat generation in the heating element 14a.

[0135] In the heat generating structure 8b, the heater 15 is formed in a rod shape, and the heat generating element 14a, the reflector 205, and the heat conducting portion 210 are formed in a cylindrical shape. The axial directions of the heat generating element 14a, the heater 15, the reflector 205, and the heat conducting portion 210 are aligned with one another.

[0136] The heating structure 8b includes a heating element 14a having a spiral cross section with a diameter increasing toward the outer periphery, and a reflector 205 provided adjacent to the radial outer periphery 201 of the heating element 14a. Heat generated from the radial outer periphery 201 of the heating element 14a is reflected by the reflector 205 and returned toward the radial outer periphery 201 of the heating element 14a. This increases the temperature of the radial outer periphery 201 of the heating element 14a, reducing the temperature difference between the radial inner periphery 200 and outer periphery 201 of the heating element 14a. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform. Therefore, the heating structure 8b can make the temperature distribution of the heating element 14a more uniform.

[0137] The heating structure 8b includes heat-conducting portions 210 provided between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction and between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205. The heat-conducting portions 210 form heat-conducting paths extending along the radial direction of the heating element 14a. The heat-conducting paths formed by the heat-conducting portions 210 transfer heat by thermal conduction between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction, and transfer heat by thermal conduction between the outer peripheral portion 201 of the heating element 14a in the radial direction and the reflector 205. Heat can be efficiently dissipated from the inner peripheral portion 200 of the heating element 14a via the outer peripheral portion 201 to the reflector 205, thereby reducing the temperature difference between the inner peripheral portion 200 and the outer peripheral portion 201 of the heating element 14a in the radial direction. As a result, the temperature distribution in the radial direction of the heating element 14a becomes more uniform. Therefore, the heat generating structure 8b can make the temperature distribution of the heat generating element 14a more uniform.

[0138] In this embodiment, the heating element 14a has a configuration in which a multilayer film 62 (see FIG. 2) is formed on the surface of a support 61 (see FIG. 2) having a spiral cross section with a diameter increasing toward the outer periphery. However, the present invention is not limited to this configuration and may have a configuration in which the multilayer film 62 is formed on the surface of a plurality of cylindrical supports 61 having different diameters spaced apart in the radial direction. In this case, too, by providing a reflector 205 adjacent to the outer periphery 201 of the heating element 14a in the radial direction, the temperature difference between the inner periphery 200 and the outer periphery 201 of the heating element 14a in the radial direction is reduced, resulting in a more uniform temperature distribution in the radial direction of the heating element 14a. Therefore, the heating structure 8b can more uniformly distribute the temperature of the heating element 14a.

[0139] The heat utilization system 1e may include, instead of the heat utilization device 4, the heat utilization device 4a of the second embodiment, the heat utilization device 4b of the third embodiment, or the heat utilization device 4c of the fourth embodiment.

[0140] Here, a simulation performed to confirm the temperature distribution of the heating element 14a of the heating structure 8b of the sixth embodiment and the heating structure of the comparative example will be described. The comparative example was a heating structure that did not include a reflector 205. The comparative example was configured similarly to the sixth embodiment except that it did not include a reflector 205. That is, in the comparative example, the radial outer periphery 201 of the heating element 14a was not covered with the reflector 205.

[0141] In a cross section including the central axis of the heater 15, the heating element 14a, and the reflector 205, the temperature from the heating surface 15a of the heater 15 to the outer surface of the reflector 205 was analyzed using commercially available thermal analysis software. The power supplied to the heater 15 from the power supply 19 was 110 W. The emissivity of the heating element 14a in the sixth embodiment and the comparative example was 0.3. The emissivity of the reflector 205 in the sixth embodiment was 0.3. The emissivity of the sealed container 5 in which the heating element 14a in the sixth embodiment and the comparative example was housed was 0.24. The emissivity of the quartz tube constituting the lamp heater as the heater 15 was 0.9.

[0142] FIG. 16 shows the results of analyzing the temperature distribution of the heat generating structure 8b of the sixth embodiment and the heat generating structure of the comparative example. In FIG. 16, the horizontal axis represents temperature, and the vertical axis represents the axial position of the heat generating element 14a (referred to as "axial position" in FIG. 16). FIG. 16 shows the temperature distribution of four heat generating elements 14a of the sixth embodiment and the comparative example, from bottom to top. It can be seen from FIG. 16 that the temperature difference between the inner periphery 200 and the outer periphery 201 of the heat generating element 14a of the sixth embodiment and the comparative example is smallest at the portion where the heat conducting portion 210 is provided and largest at the intermediate portion between adjacent heat conducting portions 210. The temperature difference between the inner periphery 200 and the outer periphery 201 of the heat generating element 14a at the intermediate portion between adjacent heat conducting portions 210 was approximately 35°C in the sixth embodiment and approximately 70°C in the comparative example. The temperature of the reflector 205 in the sixth embodiment is equivalent to the temperature of the outer circumferential portion 201 of the heating element 14a in the comparative example, and the temperature of the outer circumferential portion 201 of the heating element 14a in the sixth embodiment is higher than the temperature of the outer circumferential portion 201 of the heating element 14a in the comparative example. In the sixth embodiment, in which the outer circumferential portion 201 of the heating element 14a in the radial direction is covered with the reflector 205, the temperature of the outer circumferential portion 201 of the heating element 14a is higher than in the comparative example in which the outer circumferential portion 201 of the heating element 14a in the radial direction is not covered with the reflector 205, and therefore the temperature difference between the inner circumferential portion 200 and the outer circumferential portion 201 of the heating element 14a is smaller. This is thought to be due to the outer circumferential portion 201 of the heating element 14a being covered with the reflector 205, so that the heat (radiant heat) generated from the outer circumferential portion 201 of the heating element 14a is reflected by the reflector 205 and returned toward the outer circumferential portion 201. Therefore, it was confirmed that the heat generating structure 8b of the sixth embodiment can make the temperature distribution of the heat generating element 14a more uniform.

[0143] The present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the invention.

[0144] The heat generating device 3 is not limited to having one heat generating structure 8 , but may have a plurality of heat generating structures 8 .

[0145] The heating structure 8 is not limited to having one heating element 14, but may have a plurality of heating elements 14. The plurality of heating elements 14 are preferably arranged concentrically. It is preferable to arrange a plurality of reflecting portions 16 concentrically adjacent to the plurality of heating elements 14 arranged concentrically.

[0146] When multiple heating elements 14 are arranged concentrically, a thermally conductive material may be filled between each of the heating elements 14. The thermally conductive material may be, for example, thermally conductive particles or a thermally conductive mesh. Examples of thermally conductive materials that make up the thermally conductive particles or the thermally conductive mesh include metals such as stainless steel, titanium, nickel alloy, and gold (Au), and ceramic materials such as silicon nitride, silicon carbide, alumina, and zirconia.

[0147] The reflecting portion 16 is not limited to being formed separately from the heating element 14, but may be formed integrally with the heating element 14. Methods for forming the reflecting portion 16 integrally with the heating element 14 can be found in the manufacturing methods for heating elements disclosed in International Publications WO 2018 / 230447, WO 2020 / 122097, and WO 2020 / 122098, among others. For example, a multilayer film 62 is formed on a portion of the surface of the support 61, and a film made of a low-emissivity material is formed on the portion where the multilayer film 62 is not formed. The support 61 and the multilayer film 62 constitute the heating element 14, and the film made of the low-emissivity material constitutes the reflecting portion 16. In this manner, the heating element 14 and the reflecting portion 16 can be formed integrally. The thickness of the film made of the low-emissivity material (the reflecting portion 16) is preferably equal to or greater than the thickness of the multilayer film 62.

[0148] The heater 15 is not limited to a rod shape and may be plate-shaped. Examples of the plate-shaped heater 15 include ceramic heaters that are rectangular in plan view. The heating surface 15a of the plate-shaped heater 15 is rectangular. The rectangular heating surface 15a has a frame-shaped first heating region R1 that forms the outer edge and a rectangular second heating region R2 that forms the center. The first temperature distribution in the first heating region R1 becomes lower toward the outer edge of the heating surface 15a and higher toward the center of the heating surface 15a. The second temperature distribution in the second heating region R2 is more uniform than the first temperature distribution in the first heating region R1. When using the plate-shaped heater 15 described above, a frame-shaped reflector 16 and a rectangular heating element 14 are used. The frame-shaped first heating region R1 is covered by the frame-shaped reflector 16, and the rectangular second heating region R2 is covered by the rectangular heating element 14. This makes the thermal resistance due to the radiant heat generated from the heat generating surface 15a uniform, making the temperature distribution on the heat generating surface 15a uniform, and as a result, the temperature distribution of the heat generating element 14 can be made uniform.

[0149] 3, 3a, 3b Heat generating device 5 Sealed container 6 Hydrogen tank 7 Vacuum pump 8, 8a, 8b Heat generating structure 9 Space 10 Inlet pipe 11 Exhaust pipe 12 Supply valve 13 Exhaust valve 14, 14a Heating element 15 Heater 15a Heating surface 16, 16a, 16b Reflecting part 18 Conductive wire 17 Temperature sensor 19 Power supply 21 Control part 61 Support 62 Multilayer film 71 First layer 72 Second layer 73 Interface between different materials 205 Reflector 210 Heat conducting part R1, R1a, R1b First heating region R2 Second heating region

Claims

1. A heating structure comprising: a heating element that generates heat by absorbing and releasing hydrogen; a heater having a heating surface that generates radiant heat and that heats the heating element with the radiant heat; and a reflecting portion provided adjacent to the heating element that reflects the radiant heat, wherein the heating element has a support formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on the support, wherein the multilayer film has a first layer formed of a hydrogen storage metal or a hydrogen storage alloy and having a thickness of less than 1000 nm, and a second layer formed of a hydrogen storage metal, a hydrogen storage alloy, or a ceramic different from the first layer and also having a thickness of less than 1000 nm, wherein the heating surface has a first heating region where a first temperature distribution occurs and a second heating region where a second temperature distribution more uniform than the first temperature distribution occurs, wherein the second heating region is covered by the heating element, and the first heating region is covered by the reflecting portion.

2. The heating structure according to claim 1, wherein the heater is formed in a rod shape, the heating element and the reflecting portion are formed in a cylindrical shape, and the heating surface is surrounded by the heating element and the reflecting portion.

3. The heating structure according to claim 2, wherein the number of turns of the reflecting portion is equal to or greater than the number of turns of the heating element.

4. A heating structure according to claim 2, comprising a reflector disposed adjacent to the heating element and reflecting heat generated from the heating element, wherein the heating element has a configuration in which the multilayer film is formed on the surface of the support, which has a spiral cross section with a diameter increasing toward the outer periphery or a plurality of cylindrical shapes of different diameters arranged radially and spaced apart, and the reflector is disposed adjacent to the axial end of the heating element, and the reflector is disposed adjacent to the radial outer periphery of the heating element.

5. A heating structure comprising: a heating element that generates heat by absorbing and releasing hydrogen; a heater having a heating surface that generates radiant heat and that heats the heating element with the radiant heat; and a reflector that is provided adjacent to the heating element and reflects the heat generated by the heating element, wherein the heating element has a support formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on the support, wherein the multilayer film has a first layer that is made of a hydrogen storage metal or a hydrogen storage alloy and has a thickness of less than 1000 nm, and a second layer that is made of a hydrogen storage metal, a hydrogen storage alloy, or a ceramic that is different from the first layer and has a thickness of less than 1000 nm, wherein the heating element has a configuration in which the multilayer film is formed on the surface of the support that has a spiral cross section with a diameter that increases toward the outer periphery, or a plurality of cylindrical shapes with different diameters that are spaced apart in the radial direction, and the reflector is provided adjacent to the outer periphery of the heating element in the radial direction.

6. A heating structure as described in claim 5, comprising a heat conducting portion provided between the inner and outer circumferential portions of the heating element in the radial direction and between the outer circumferential portion of the heating element in the radial direction and the reflector, and constituting a heat conduction path extending along the radial direction of the heating element.

7. A heat generating device comprising: a heat generating structure according to any one of claims 1 to 6; a sealed container that houses said heat generating structure; a supply unit that supplies a hydrogen-based gas containing hydrogen into the sealed container; and a discharge unit that discharges said hydrogen-based gas from the sealed container.

Images