Heat generating structure and heat generating device

Abstract

Provided are a heat generating structure and a heat generating device capable of equalizing a temperature distribution of a heat generating element and increasing an area of a heat generating surface. A heat generating structure 8 includes: a heat generating element 14 including a support formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on the support and configured to generate heat by occluding and discharging hydrogen; and a heater 15 formed into a cylindrical shape and having an outer peripheral surface 15a surrounded by the heat generating element 14. The heat generating element 14 includes the inner edge 51 disposed to face the outer peripheral surface 15a, the outer edge 52 disposed farther away from the outer peripheral surface 15a than the inner edge 51 in the second direction orthogonal to the first direction along the central axis CL of the heater 15, and the heat generating surface 53 connecting the inner edge 51 and the outer edge 52 and extending continuously in a circumferential direction around the central axis CL. The heat generating element 14 transfers heat from the inner edge 51 to the outer edge 52 by heat conduction.

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 heating 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 spirally 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 heat output of a heating element can be increased by increasing the area of ​​the heating surface, which is composed of the surface of a multilayer film. Because heat transfer by gas convection cannot be expected inside an evacuated sealed container, heat is transferred from the heater to the heating element by radiation, and also by thermal conduction from the high-temperature side to the low-temperature side inside the heating element. Therefore, the larger the area of ​​the heating element's heating surface, the greater the temperature difference between the high-temperature and low-temperature sides of the heating element. Furthermore, when multiple heating elements are placed inside a sealed container, the heating surfaces of the heating elements come into contact with each other, resulting in a decrease in heat output and fusion between the heating elements due to thermal diffusion of metals.

[0006] The heating device of Patent Document 1 has a cylindrical heater whose outer peripheral surface is surrounded by a wound heating element, and is configured so that the heater can efficiently heat the wound heating element. However, in the heating device of Patent Document 1, radiant heat from the heater is not easily transmitted to the outer peripheral portion of the wound heating element in the spiral direction, resulting in a temperature difference between the inner and outer peripheral portions of the wound heating element in the spiral direction, making it difficult to uniformize the temperature distribution of the wound heating element. Furthermore, the temperature difference between the inner and outer peripheral portions of the wound heating element increases as the number of turns of the wound heating element increases, making it difficult to increase the area of ​​the heating surface.

[0007] 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 and increase the area of ​​the heat generating surface.

[0008] The heat-generating structure according to the present invention comprises: a support formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor; a heat-generating element having a multilayer film provided on the support and generating heat by absorbing and releasing hydrogen; and a heater formed in a cylindrical shape and having an outer peripheral surface surrounded by the heat-generating element, wherein the multilayer film has a first layer having a thickness of less than 1000 nm and formed of a hydrogen storage metal or hydrogen storage alloy, and a second layer having a thickness of less than 1000 nm and formed of a hydrogen storage metal, hydrogen storage alloy, or ceramic different from the first layer, and the heat-generating element has an inner edge portion disposed opposite the outer peripheral surface, and an outer edge portion disposed spaced apart from the outer peripheral surface in a second direction perpendicular to a first direction along a central axis of the heater more than the inner edge portion, and a heat-generating surface connecting the inner edge portion and the outer edge portion and extending continuously in a circumferential direction centered on the central axis, and heat is transferred from the inner edge portion to the outer edge portion by thermal conduction.

[0009] 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.

[0010] According to the present invention, the temperature distribution of the heating element can be made uniform and the area of ​​the heating surface can be increased.

[0011] 6 is a conceptual diagram showing the configuration of a heat utilization system according to a first embodiment. FIG. 7 is an exploded perspective view of a heat utilization structure according to the first embodiment. FIG. 8 is a cross-sectional view showing the configuration of a heat generating element. FIG. 9 is a graph showing the temperature distribution of the heat utilization structure according to the first embodiment. FIG. 10 is an exploded perspective view of a heat utilization structure according to a second embodiment. FIG. 11 is a conceptual diagram showing the configuration of a heat utilization system according to a third embodiment. FIG. 12 is a schematic cross-sectional view of the heat utilization structure taken along line VII-VII in FIG. 6. FIG. 13 is an exploded perspective view of a heat utilization structure according to a third embodiment. FIG. 14 is a graph showing the temperature distribution of the heat utilization structure according to the third embodiment. FIG. 15 is a conceptual diagram showing the configuration of a heat utilization system according to a fourth embodiment. FIG. 16 is a conceptual diagram showing the configuration of a heat utilization system according to a fifth embodiment. FIG. 17 is a conceptual diagram showing the configuration of a heat utilization system according to a sixth embodiment.

[0012] 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.

[0013] (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.

[0014] 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.

[0015] 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 .

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The heat generating structure 8 includes a heat generating element 14 that generates heat by absorbing and releasing hydrogen, a heater 15 that heats the heat generating element 14 , and a temperature sensor 17 that detects the temperature of the heat generating element 14 .

[0025] The heating element 14 is formed in a plate shape with a through hole. In this embodiment, the heating element 14 is formed in an annular shape with a circular through hole in the center. A heater 15 is disposed in the through hole of the heating element 14. A plurality of heating elements 14 are disposed in a first direction along the central axis CL of the heater 15 (see FIG. 2 ). That is, the heating structure 8 includes a plurality of heating elements 14 disposed in the first direction. Note that the shape of the heating element 14 is not limited to an annular shape, and may be a polygonal annular shape, for example. The configuration of the heating element 14 will be described later using another drawing.

[0026] The heater 15 is formed in a hollow or solid cylindrical shape. In this embodiment, the heater 15 is formed in a solid cylindrical shape and has a uniform diameter throughout its entire length in the first direction along the central axis CL. Note that "uniform" includes not only strictly uniform but also approximately uniform, i.e., variations within the scope of the invention. The shape of the heater 15 is not limited to a cylindrical shape and may be other appropriate shapes, such as an elliptical cylindrical shape or a rectangular cylindrical shape. Examples of cylindrical heaters 15 include sheathed heaters, ceramic heaters, and lamp heaters. 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 within the pipe except for a portion extending 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 a power source via the pair of terminals. The pipe is heated by Joule heat generated by the heating wire.

[0027] The heater 15 has an outer peripheral surface 15a surrounded by the heating element 14. In this embodiment, the outer peripheral surface 15a is a cylindrical surface. The heater 15 generates radiant heat from the outer peripheral surface 15a.

[0028] 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 outer peripheral surface 15a. The heater 15 heats the heating element 14 by radiant heat generated from the outer peripheral 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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 .

[0033] 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 .

[0034] 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).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] FIG. 2 is an exploded perspective view of the heating structure 8 according to the first embodiment. As shown in FIG. 2 , the heating element 14 includes an inner edge portion 51 disposed opposite the outer peripheral surface 15a of the heater 15, an outer edge portion 52 disposed spaced apart from the outer peripheral surface 15a in a second direction perpendicular to the first direction along the central axis CL of the heater 15, and a heating surface 53 connecting the inner edge portion 51 and the outer edge portion 52 and extending continuously in the circumferential direction centered on the central axis CL. The inner edge portion 51 and the outer edge portion 52 extend continuously in the circumferential direction centered on the central axis CL of the heater 15. The heating surface 53 is disposed in a plane perpendicular to the first direction along the central axis CL of the heater 15. "Continuous" means that the heating surface 53 is continuous throughout the circumferential direction centered on the central axis CL. The second direction is a radial direction (also referred to as a "radial direction") centered on the central axis CL.

[0042] The inner edge portion 51 is arranged around the entire circumference in the circumferential direction. A through hole of the heating element 14 is formed by the inner edge portion 51. The inner edge portion 51 is provided at a position spaced apart from the outer peripheral surface 15a of the heater 15 in the second direction. A gap is formed between the inner edge portion 51 of the heating element 14 and the outer peripheral surface 15a of the heater 15. The diameter of the inner edge portion 51 is larger than the diameter of the heater 15. The diameter of the inner edge portion 51 is the inner diameter of the heating element 14. For example, if the heating element 14 is a polygonal ring, the inner diameter of the heating element 14 is the diameter of the inscribed circle of the inner edge portion 51.

[0043] The outer edge portion 52 is arranged around the entire circumference in the circumferential direction. The outer edge portion 52 is provided at a position spaced apart in the second direction from the inner surface of the sealed container 5 (the inner surface of the trunk). A gap is formed between the outer edge portion 52 of the heating element 14 and the inner surface of the sealed container 5. The diameter of the outer edge portion 52 is smaller than the inner diameter of the sealed container 5. The inner diameter of the sealed container 5 is the diameter of the inner surface of the trunk. The diameter of the outer edge portion 52 is the outer diameter of the heating element 14. For example, if the heating element 14 is a polygonal ring, the outer diameter of the heating element 14 is the diameter of the circumscribing circle of the outer edge portion 52.

[0044] The heating surface 53 extends continuously from the inner edge 51 to the outer edge 52. That is, the heating surface 53 extends continuously in a second direction perpendicular to the first direction. The heating surface 53 is formed in an annular shape. The heating surface 53 is the surface of a multilayer film 62 (see FIG. 3 ), which will be described later. The larger the area of ​​the heating surface 53, the greater the amount of heat generated by the heating element 14. The amount of heat generated by the heating element 14 refers to the amount of heat generated when hydrogen atoms pass through a dissimilar material interface 73, which will be described later, by quantum diffusion, or when hydrogen atoms diffuse through the dissimilar material interface 73 by quantum diffusion.

[0045] The heating element 14 receives radiant heat generated from the outer peripheral surface 15a of the heater 15 at the inner peripheral portion 51. The temperature of the inner peripheral portion 51 rises due to the radiant heat from the outer peripheral surface 15a of the heater 15. The heat from the inner peripheral portion 51 is transferred to the outer peripheral portion 52 by thermal conduction. That is, the heating element 14 transfers heat from the inner peripheral portion 51 to the outer peripheral portion 52 by thermal conduction. The temperature of the outer peripheral portion 52 rises due to thermal conduction from the inner peripheral portion 51. This reduces the temperature difference between the inner peripheral portion 51 and the outer peripheral portion 52, making the temperature distribution of the heating element 14 more uniform.

[0046] The heat generating structure 8 includes spacers 55 provided between adjacent heat generating elements 14 among the plurality of heat generating elements 14 arranged along the first direction. The spacers 55 are formed of a heat-resistant and pressure-resistant material. The spacers 55 form spaces between adjacent heat generating elements 14 to prevent contact between the adjacent heat generating elements 14. The spacers 55 position the plurality of heat generating elements 14 in the first direction.

[0047] The spacer 55 abuts against the outer peripheral surface 15a of the heater 15. The spacer 55 is formed in an annular shape. The heater 15 is inserted into an opening formed by the inner edge of the spacer 55. The spacer 55 is fixed to the outer peripheral surface 15a of the heater 15 by having its inner edge abut against the outer peripheral surface 15a of the heater 15. In this embodiment, the spacer 55 is formed in an annular shape. Note that the spacer 55 is not limited to an annular shape, and may be a polygonal annular shape, for example.

[0048] Next, the configuration of the heating element 14 will be described. FIG. 3 is a cross-sectional view showing the configuration of the heating element 14. As shown in FIG. 3, 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.

[0049] In Figure 3, the multilayer film 62 is configured to be laminated on one surface (e.g., the front surface) of the support body 61, but this is not limited to this, and the multilayer film 62 may be configured to be laminated on the other surface (e.g., the back surface) of the support body 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 body 61.

[0050] 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 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 outer peripheral surface 15a of the heater 15 increases as a result of the power supply. The inner edge 51 of the heating element 14 receives radiant heat generated from the outer peripheral surface 15a of the heater 15. The temperature of the inner edge 51 increases due to the radiant heat from the outer peripheral surface 15a of the heater 15. The inner edge 51 and outer edge 52 of the heating element 14 are continuously connected by the heating surface 53, and heat from the inner edge 51 is transferred to the outer edge 52 by thermal conduction. The temperature of the outer edge 52 rises due to thermal conduction from the inner edge 51. The temperature difference between the inner edge 51 and the outer edge 52 becomes smaller, and 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 setting the temperature of the heating element 14 to about 200°C, moisture can be removed from the heating element 14.

[0051] 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.

[0052] 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.

[0053] In the heat-generating structure 8 according to this embodiment, the inner edge 51 and outer edge 52 of the heat-generating element 14 are connected by a heat-generating surface 53, and the heat-generating surface 53 extends continuously in the circumferential direction around the central axis CL of the heater 15. The inner edge 51 of the heat-generating element 14 is heated by radiant heat generated from the outer peripheral surface 15a of the heater 15. At this time, the heat of the inner edge 51 of the heat-generating element 14 is transferred to the outer edge 52 by thermal conduction. As a result, heat is transferred throughout the entire heat-generating element 14, and the temperature difference between the inner edge 51 and outer edge 52 of the heat-generating element 14 is reduced. Therefore, the heat-generating structure 8 can homogenize the temperature distribution of the heat-generating element 14.

[0054] The results of analyzing the temperature distribution of the heating structure 8 are shown in Figure 4. The temperature from the central axis CL of the heater 15 to the inner surface of the sealed container 5 was analyzed in a cross section including the central axis CL of the heater 15 and the inner and outer edges 51 and 52 of the heating element 14. A simulation of thermal conduction and radiation was performed using commercially available thermal analysis software. The power supplied to the heater 15 from the power source 19 was 400 W. In Figure 4, the horizontal axis represents the radial (radiation) position around the central axis CL of the heater 15, and the vertical axis represents the temperature. Figure 4 confirms that the temperatures of the inner and outer edges 51 and 52 of the heating element 14 were approximately 550°C, and the temperature distribution of the heating element 14 was uniform. This is thought to be due to the fact that the inner and outer edges 51 and 52 of the heating element 14 are continuously connected by the heating surface 53, which allows heat to be conducted throughout the heating element 14, thereby reducing the temperature difference between the inner and outer edges 51 and 52.

[0055] In the heat-generating structure 8, the heat-generating element 14 is arranged along the first direction, so that the total area obtained by adding up the areas of the heat-generating surfaces 53 increases, and the amount of heat generated increases. The heat-generating structure 8 can easily increase the total area of ​​the heat-generating surfaces 53 simply by increasing the number of heat-generating elements 14. The heat-generating structure 8 can easily increase or decrease the amount of heat generated by changing the number of heat-generating elements 14.

[0056] The heating structure 8 includes spacers 55 provided between adjacent heating elements 14 among the plurality of heating elements 14 arranged along the first direction, thereby forming spaces between adjacent heating elements 14 and preventing contact between the adjacent heating elements 14. This prevents a decrease in the amount of heat generated due to contact between the heating surfaces 53 of the heating elements 14 and fusion between the heating elements 14 due to thermal diffusion of metal. Each heating element 14 is efficiently heated by radiant heat from adjacent heating elements 14, allowing it to reach the optimum temperature for heat generation in a shorter time.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] In the heat utilization system 1, a heating element 14 is provided around the heater 15, covering the outer peripheral 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.

[0061] (2) Heat-generating structure according to the second embodiment In the first embodiment, a spacer 55 is provided between adjacent heating elements 14 among the plurality of heating elements 14 arranged along the first direction, but in the second embodiment, in addition to the spacer, a pair of end members are provided adjacent to the heating elements 14 arranged at the ends in the first direction.

[0062] 5 is an exploded perspective view of a heat generating structure 8a according to the second embodiment. The heat generating structure 8a can be used in place of the heat generating structure 8 in the heat generating device 3 according to the first embodiment. Note that components and members that are the same as or equivalent to those in the first embodiment are denoted by the same reference numerals and descriptions thereof will be omitted.

[0063] 5, the heat generating structure 8a includes a heat generating element 14, a heater 15, and a temperature sensor 17 (not shown). The heat generating elements 14 are arranged in a first direction along the central axis CL of the heater 15.

[0064] The heating structure 8a includes a spacer 75 provided between adjacent heating elements 14 among the plurality of heating elements 14 arranged along the first direction, and a pair of end members 76 provided adjacent to the heating element 14 arranged at the end of the first direction among the plurality of heating elements 14 arranged along the first direction.

[0065] The spacers 75 are made of a heat-resistant and pressure-resistant material. The spacers 75 form spaces between adjacent heating elements 14. The spacers 75 prevent contact between adjacent heating elements 14. The spacers 75 position the multiple heating elements 14 in a first direction. The spacers 75 have a first frame portion 78 and a first protrusion 79.

[0066] The first frame portion 78 is disposed spaced apart from the outer peripheral surface 15a of the heater 15 in the second direction. The first frame portion 78 is formed in an annular shape. The heater 15 is inserted into an opening formed by the inner edge of the first frame portion 78. A gap is formed between the inner edge of the first frame portion 78 and the outer peripheral surface 15a of the heater 15. The inner diameter of the first frame portion 78 is the inner diameter of the spacer 75, and the outer diameter of the first frame portion 78 is the outer diameter of the spacer 75. The outer diameter of the first frame portion 78 is larger than the outer diameter of the heating element 14. In this embodiment, the first frame portion 78 is formed in an annular shape. Note that the first frame portion 78 is not limited to an annular shape, and may be a polygonal annular shape, for example.

[0067] The first protrusion 79 protrudes in a first direction from the first frame 78 and abuts against the outer edge 52 of the heating element 14. The first protrusion 79 is composed of a plurality of first pins spaced apart in the circumferential direction. The inner edges of the first pins abut against the outer edge 52 of the heating element 14.

[0068] The pair of end members 76 sandwich the plurality of heating elements 14 and the plurality of spacers 75 from the first direction. The pair of end members 76 have the same configuration. The end members 76 have an inner frame portion 81, an outer frame portion 82, a connecting portion 83, and a second protrusion portion 84.

[0069] The inner frame portion 81 abuts against the outer peripheral surface 15a of the heater 15. The inner frame portion 81 is formed in an annular shape. The heater 15 is inserted into an opening formed by the inner edge of the inner frame portion 81. The inner edge of the inner frame portion 81 abuts against the outer peripheral surface 15a of the heater 15, thereby fixing the end member 76 to the outer peripheral surface 15a of the heater 15. In this embodiment, the inner frame portion 81 is formed in an annular shape. Note that the shape of the inner frame portion 81 is not limited to an annular shape, and it may be a polygonal annular shape, for example.

[0070] The outer frame portion 82 is disposed at a greater distance in the second direction from the outer peripheral surface 15a of the heater 15 than the inner frame portion 81. The outer frame portion 82 is formed in an annular shape. The inner frame portion 81 is disposed in an opening formed by the inner edge of the outer frame portion 82. In this embodiment, the outer frame portion 82 is formed in an annular shape. Note that the shape of the outer frame portion 82 is not limited to an annular shape, and it may be a polygonal annular shape, for example.

[0071] The connecting portions 83 connect the inner frame portion 81 and the outer frame portion 82. A plurality of connecting portions 83 are arranged at intervals in the circumferential direction. In other words, the end member 76 has a configuration in which the plurality of connecting portions 83 connect the inner frame portion 81 and the outer frame portion 82, and the plurality of connecting portions 83 are arranged at intervals in the circumferential direction. Gaps are formed between the plurality of connecting portions 83. In FIG. 5 , four connecting portions 83 are arranged to extend radially from the central axis CL of the heater 15.

[0072] The second protrusion 84 protrudes from the outer frame 82 in the first direction and abuts against the outer edge 52 of the heating element 14. The second protrusion 84 is composed of a plurality of second pins spaced apart in the circumferential direction. The inner edges of the second pins abut against the outer edge 52 of the heating element 14.

[0073] In the heat-generating structure 8a according to the second embodiment, the inner edge 51 and outer edge 52 of the heat-generating element 14 are connected by a heat-generating surface 53, and the heat-generating surface 53 extends continuously in the circumferential direction around the central axis CL of the heater 15. The inner edge 51 of the heat-generating element 14 is heated by radiant heat generated from the outer peripheral surface 15a of the heater 15. At this time, the heat of the inner edge 51 of the heat-generating element 14 is transferred to the outer edge 52 by thermal conduction. As a result, heat is transferred throughout the entire heat-generating element 14, and the temperature difference between the inner edge 51 and outer edge 52 of the heat-generating element 14 is reduced. Therefore, the heat-generating structure 8a can uniformly distribute the temperature of the heat-generating element 14.

[0074] In the heat generating structure 8a, the heat generating elements 14 are arranged along the first direction, so that the total area of ​​the heat generating surface 53 increases, and the amount of heat generated increases. The heat generating structure 8a can adjust the amount of heat generated according to the number of heat generating elements 14.

[0075] In the heating structure 8a, spacers 75 are provided between adjacent heating elements 14 among the multiple heating elements 14 arranged along the first direction, thereby forming spaces between the adjacent heating elements 14 and preventing contact between the adjacent heating elements 14. This prevents a decrease in the amount of heat generated due to contact between the heating surfaces 53 of the heating elements 14 and fusion between the heating elements 14 due to thermal diffusion of metal. Each heating element 14 is efficiently heated by radiant heat from the adjacent heating elements 14, allowing it to reach the optimum temperature for heat generation in a shorter time.

[0076] The heating structure 8a includes, in addition to a spacer 75, a pair of end members 76 provided adjacent to the heating element 14 arranged at the end in the first direction among the multiple heating elements 14 arranged along the first direction. In the heating structure 8a, the first protrusion 79 of the spacer 75 abuts against the outer edge 52 of the heating element 14, the second protrusion 84 of the end member 76 abuts against the outer edge 52 of the heating element 14, and the end member 76 is fixed to the outer peripheral surface 15a of the heater 15 by the inner frame portion 81, thereby integrating the multiple heating elements 14, the heater 15, the multiple spacers 75, and the pair of end members 76. This positions the multiple heating elements 14, the multiple spacers 75, and the pair of end members 76 relative to the heater 15 in the first and second directions.

[0077] (3) Heat Utilization System According to a Third Embodiment In the first and second embodiments, the heating element 14 is formed in an annular shape, but in a third embodiment, the shape of the heating element is different.

[0078] 6 is a conceptual diagram showing the configuration of a heat utilization system 1a according to a third embodiment. The heat utilization system 1a 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 in the above embodiments are given the same reference numerals and will not be described again.

[0079] The heat generating device 3a includes a sealed container 5, a hydrogen tank 6, a vacuum pump 7, and a heat generating structure 8b. The heat generating device 3a includes a heat generating structure 8b instead of the heat generating structure 8 according to the first embodiment. The heat generating structure 8b includes a heat generating element 14a that generates heat by absorbing and releasing hydrogen, a heater 15 that heats the heat generating element 14a, and a temperature sensor 17 that detects the temperature of the heat generating element 14a.

[0080] The heating element 14a is formed in a hollow cylindrical shape. The heater 15 is disposed in the space inside the heating element 14a. The heating element 14a extends continuously in a first direction along the central axis CL of the heater 15, and also extends continuously in a zigzag manner in the circumferential direction around the central axis CL.

[0081] The specific shape of the heating element 14a will be described using Figure 7. Figure 7 is a schematic cross-sectional view of the heating structure 8b taken along line VII-VII in Figure 6. As shown in Figure 7, the heating element 14a is configured such that it is folded back multiple times alternately inward and outward around the central axis CL of the heater 15, with both ends connected. In a plan view seen from the first direction, the heating element 14a has a shape (also referred to as a star shape) that extends continuously in a zigzag pattern in the circumferential direction around the central axis CL.

[0082] The heating element 14a has an inner edge portion 91 disposed opposite the outer peripheral surface 15a of the heater 15, an outer edge portion 92 disposed spaced apart from the inner edge portion 91 in a second direction perpendicular to the first direction along the central axis CL, and a heating surface 93 connecting the inner edge portion 91 and the outer edge portion 92 and extending continuously in the circumferential direction centered on the central axis CL. The inner edge portion 91 and the outer edge portion 92 are arranged intermittently in the circumferential direction centered on the central axis CL. The heating surface 93 extends continuously in the circumferential direction centered on the central axis CL, while alternately folding back multiple times. "Intermittent" means that the heating element 14a is not continuous in the circumferential direction centered on the central axis CL. That is, the heating element 14a has a plurality of inner edge portions 91 arranged intermittently in the circumferential direction, a plurality of outer edge portions 92 arranged intermittently in the circumferential direction, and the heating surface 93 extending continuously in the circumferential direction while alternately folding back multiple times.

[0083] The inner edge portion 91 forms an inner folded portion of the heating element 14a. The inner edge portion 91 extends in a first direction. The inner edge portion 91 is provided at a position spaced apart from the outer peripheral surface 15a of the heater 15 in a second direction. A gap is formed between the inner edge portion 91 and the outer peripheral surface 15a.

[0084] The outer edge portion 92 forms an outer folded portion of the heating element 14a. The outer edge portion 92 extends in a first direction. The outer edge portion 92 is provided at a position spaced apart from the inner surface of the sealed container 5 (the inner surface of the body) in a second direction. A gap is formed between the outer edge portion 92 and the inner surface of the sealed container 5.

[0085] The heating surface 93 is folded outward (toward the outer edge 92) at the inner edge 91 and inward (toward the inner edge 91) at the outer edge 92. The heating surface 93 is composed of a first surface 93a and a second surface 93b inclined with respect to an imaginary plane 94 perpendicular to the outer peripheral surface 15a of the heater 15. In FIG. 7 , the imaginary plane 94 is indicated by a two-dot chain line. The first surface 93a and the second surface 93b are arranged symmetrically with respect to the imaginary plane 94. The first surface 93a and the second surface 93b are arranged alternately in the circumferential direction around the central axis CL. A space is formed between adjacent first surfaces 93a and second surfaces 93b. Adjacent first surfaces 93a and second surfaces 93b are arranged facing each other and connected by the inner edge 91 or the outer edge 92. The plurality of first surfaces 93 a and the plurality of second surfaces 93 b are alternately connected by the inner edge portion 91 and the outer edge portion 92 to form a single continuous heat generating surface 93. The heat generating surface 93 is arranged around the central axis CL in the circumferential direction.

[0086] The heating element 14a receives radiant heat generated from the outer peripheral surface 15a of the heater 15 at its inner edge 91. The temperature of the inner edge 91 rises due to the radiant heat from the outer peripheral surface 15a of the heater 15. The heat from the inner edge 91 is transferred to the outer edge 92 by thermal conduction. That is, the heating element 14a transfers heat from the inner edge 91 to the outer edge 92 by thermal conduction. The temperature of the outer edge 92 rises due to thermal conduction from the inner edge 91. This reduces the temperature difference between the inner edge 91 and the outer edge 92, making the temperature distribution of the heating element 14a uniform.

[0087] 8 is an exploded perspective view of a heat generating structure 8b according to a third embodiment. As shown in FIG. 8, the heat generating structure 8b includes a retaining portion 95 that maintains the shape of the heat generating element 14a. The retaining portion 95 is formed of a heat-resistant and pressure-resistant material. The retaining portion 95 maintains the space formed between the first surface 93a and the second surface 93b that constitute the heat generating surface 93 of the heat generating element 14a, and prevents contact between the adjacent first surface 93a and second surface 93b.

[0088] The holding portion 95 has a support 96 fixed to the sealed container 5, a first guide portion 97 provided at one end of the support 96, and a second guide portion 98 provided between one end and the other end of the support 96. In this embodiment, four support columns 96 are suspended from the top lid of the sealed container 5. Note that the support columns 96 are not limited to being suspended from the top lid of the sealed container 5, and may be provided in an upright position relative to the bottom lid of the sealed container 5. The support columns 96 may be fixed to the body of the sealed container 5 so as to extend in the second direction.

[0089] The first guide portion 97 receives one end of the heating element 14a in the first direction. The first guide portion 97 is formed in a disk shape with an opening 97a in the center. The heater 15 is inserted into the opening 97a of the first guide portion 97.

[0090] The first guide portion 97 has a first groove portion 97b into which one end portion of the heating element 14a in the first direction is fitted. The first groove portion 97b extends continuously while alternately folding back and forth multiple times in the circumferential direction. The first groove portion 97b positions the one end portion of the heating element 14a in the first direction. The width of the first groove portion 97b is slightly larger than the thickness of the heating element 14a. The depth of the first groove portion 97b is not particularly limited. The first groove portion 97b may be configured to penetrate the first guide portion 97 in the first direction.

[0091] The second guide portion 98 receives the other end of the heating element 14a in the first direction. The second guide portion 98 is formed in a disk shape with an opening 98a in the center. The heater 15 is inserted into the opening 98a of the second guide portion 98.

[0092] The second guide portion 98 has a second groove portion 98b into which the other end portion of the heating element 14a in the first direction is fitted. The second groove portion 98b extends continuously while alternately folding back multiple times in the circumferential direction. The second groove portion 98b positions the other end portion of the heating element 14a in the first direction. The width of the second groove portion 98b is slightly larger than the thickness of the heating element 14a. The depth of the second groove portion 98b is not particularly limited. The second groove portion 98b may be configured to penetrate the second guide portion 98 in the first direction.

[0093] In the heat-generating structure 8b according to the third embodiment, the inner edge portions 91 and outer edge portions 92 of the heat-generating element 14a are arranged intermittently in the circumferential direction, and the heat-generating surface 93 extends continuously, alternately folding back and forth multiple times in the circumferential direction. The inner edge portion 91 of the heat-generating element 14a is heated by radiant heat generated from the outer peripheral surface 15a of the heater 15. At this time, in the heat-generating element 14a, the heat of the inner edge portion 91 is transferred to the outer edge portion 92 by thermal conduction. As a result, heat is transferred throughout the entire heat-generating element 14a, and the temperature difference between the inner edge portion 91 and the outer edge portion 92 of the heat-generating element 14a is reduced. Therefore, the heat-generating structure 8b can uniformly distribute the temperature of the heat-generating element 14a.

[0094] The heating structure 8b has a plurality of first faces 93a and second faces 93b that constitute the heating surface 93 of the heating element 14a, arranged alternately in the circumferential direction, with a space formed between adjacent first faces 93a and second faces 93b. The heating structure 8b can receive radiant heat from the outer peripheral surface 15a of the heater 15 over the entire heating surface 93 through the space, thereby reducing the temperature difference between the inner edge 91 and outer edge 92 of the heating element 14a and making the temperature distribution of the heating element 14a more uniform.

[0095] The heating structure 8b has a first surface 93a and a second surface 93b that face each other. The first surface 93a is efficiently heated by radiant heat from the adjacent second surface 93b. The second surface 93b is efficiently heated by radiant heat from the adjacent first surface 93a. This allows the heating element 14a to reach an optimum temperature for heat generation in a shorter time.

[0096] The heating structure 8b includes a retaining portion 95 that maintains the shape of the heating element 14a. The retaining portion 95 has a first groove 97b into which one end of the heating element 14a in the first direction fits, and a second groove 98b into which the other end of the heating element 14a in the first direction fits. The first groove 97b and the second groove 98b extend continuously, alternately folding back and forth multiple times in the circumferential direction around the central axis CL. The retaining portion 95 maintains a space between the first surface 93a and the second surface 93b that constitute the heating surface 93 of the heating element 14a, preventing contact between adjacent first and second surfaces 93a and 93b. The heating structure 8b suppresses a decrease in heat generation due to contact between the first and second surfaces 93a and 93b, and suppresses fusion between the first and second surfaces 93a and 93b due to thermal diffusion of metals.

[0097] FIG. 9 shows the results of analyzing the temperature distribution of the heating structure 8b. In a cross section including the central axis CL of the heater 15 and the outer edge 92 of the heating element 14a, the temperature from the central axis CL of the heater 15 to the inner surface of the sealed container 5 was analyzed. A simulation of thermal conduction and radiation was performed using commercially available thermal analysis software. The power supplied to the heater 15 from the power source 19 was 600 W. In FIG. 9, the horizontal axis represents the radial (radiation) position around the central axis CL of the heater 15, and the vertical axis represents the temperature. In FIG. 9, a portion of the graph from the central axis CL to the outer peripheral surface 15a of the heater 15 is omitted. The black squares represent the temperatures of the inner edge 91 and outer edge 92 of the heating element 14a. From FIG. 9, it was confirmed that the temperatures of the inner edge 91 and outer edge 92 of the heating element 14a were approximately 600°C, and the temperature distribution of the heating element 14a was uniform. It is believed that the inner edge 91 and outer edge 92 of the heating element 14a are continuously connected by the heating surface 93, which allows heat to be transmitted throughout the entire heating element 14a, thereby reducing the temperature difference between the inner edge 91 and outer edge 92.

[0098] (4) Heat Utilization System According to the Fourth Embodiment Fig. 10 is a conceptual diagram showing the configuration of a heat utilization system 1b according to the fourth embodiment. The heat utilization system 1b 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 fourth embodiment, water is used as the heat medium. 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] (5) Heat Utilization System According to the Fifth Embodiment Fig. 11 is a conceptual diagram showing the general configuration of a heat utilization system 1c according to the fifth embodiment. The heat utilization system 1c 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] (6) Heat Utilization System According to the Sixth Embodiment Fig. 12 is a conceptual diagram showing the configuration of a heat utilization system 1d according to the sixth embodiment. The heat utilization system 1d 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.

[0115] 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.

[0116] 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.

[0117] As described above, the heat utilization system 1d 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.

[0118] The present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the invention.

[0119] 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 .

[0120] In the heat utilization systems 1b, 1c, and 1d, the heat generating device 3 may be provided with a heat generating structure 8a instead of the heat generating structure 8. The heat utilization systems 1b, 1c, and 1d may be provided with a heat generating device 3a instead of the heat generating device 3.

[0121] 3, 3a 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 Outer peripheral surface 17 Temperature sensor 18 Conductive wire 19 Power supply 21 Control unit 51, 91 Inner edge portion 52, 92 Outer edge portion 53, 93 Heating surface 55, 75 Spacer 61 Support 62 Multilayer film 71 First layer 72 Second layer 73 Interface between different materials 76 End member 78 First frame portion 79 First protrusion 81 Inner frame portion 82 Outer frame portion 83 Connecting portion 84 Second protrusion 93a First surface 93b Second surface CL Central axis

Claims

1. A heating element comprising: a support formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor; a multilayer film attached to the support that generates heat by absorbing and releasing hydrogen; and a cylindrical heater having an outer circumferential surface surrounded by the heating element, wherein the multilayer film has a first layer less than 1000 nm thick and formed of a hydrogen storage metal or hydrogen storage alloy, and a second layer less than 1000 nm thick and formed of a hydrogen storage metal, hydrogen storage alloy, or ceramic different from the first layer, wherein the heating element has an inner periphery disposed opposite the outer periphery, and an outer periphery disposed more distant from the outer periphery in a second direction perpendicular to a first direction along the central axis of the heater than the inner periphery, and a heating surface connecting the inner periphery and the outer periphery and extending continuously in a circumferential direction centered on the central axis, and wherein heat is transferred from the inner periphery to the outer periphery by thermal conduction.

2. The heat-generating structure according to claim 1, wherein the inner edge and the outer edge extend continuously in the circumferential direction, and the heat-generating surface is disposed in a plane perpendicular to the first direction.

3. The heat generating structure according to claim 2, wherein a plurality of the heat generating elements are arranged in the first direction.

4. The heat generating structure according to claim 3, further comprising a spacer provided between adjacent heat generating elements among the plurality of heat generating elements arranged along the first direction.

5. A heating structure as described in claim 4, comprising a pair of terminal members arranged adjacent to a heating element arranged at an end in the first direction among a plurality of heating elements arranged along the first direction, wherein the spacer has a first frame portion arranged spaced apart in the second direction from the outer peripheral surface, and a first protruding portion arranged to protrude from the first frame portion in the first direction and abutting the outer edge of the heating element, and the terminal members have an inner frame portion abutting the outer peripheral surface, an outer frame portion arranged to be spaced apart in the second direction from the outer peripheral surface further than the inner frame portion, a connecting portion connecting the inner frame portion and the outer frame portion, and a second protruding portion arranged to protrude from the outer frame portion in the first direction and abutting the outer edge of the heating element.

6. A heat generating structure as described in claim 5, wherein the first protrusion is composed of a plurality of first pins arranged at intervals in the circumferential direction, and the second protrusion is composed of a plurality of second pins arranged at intervals in the circumferential direction.

7. The heat-generating structure according to claim 1, wherein the inner edge portions and the outer edge portions are arranged intermittently in the circumferential direction, and the heat-generating surface extends continuously in the circumferential direction while alternately folding back and forth multiple times.

8. The heating structure according to claim 7, further comprising a retaining portion that retains the shape of the heating element, the retaining portion having a groove into which an end portion of the heating element in the first direction is fitted, the groove extending continuously in the circumferential direction while alternately folding back multiple times.

9. A heat generating device comprising: a heat generating structure according to any one of claims 1 to 8; 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 a discharge unit that discharges the hydrogen-based gas from the sealed container.