Heat generating structure and heat generating device

Abstract

Provided are a heat generating structure and a heat generating device capable of uniformizing the temperature distribution of a heat generating body and increasing the area of a heat generating surface. A heat generating structure 8 comprises: a heat generating body 14 having a support body formed of a hydrogen storage metal, a hydrogen storage alloy, or a proton conductor, and a multilayer film provided on the support body and generating heat by occlusion and release of hydrogen; and a heater 15 formed in a cylindrical shape and having an outer peripheral surface 15a surrounded by the heat generating body 14. The heat generating body 14 has: an inner edge part 51 disposed facing the outer peripheral surface 15a; an outer edge part 52 disposed at a position spaced apart from the inner edge part 51 in a second direction, orthogonal to a first direction along a center axis CL of the heater 15, with respect to the outer peripheral surface 15a; and a heat generating surface 53 connecting the inner edge part 51 and the outer edge part 52, and continuously extending in a circumferential direction centered on the center axis CL. Heat is transmitted from the inner edge part 51 to the outer edge part 52 through heat conduction.

Description

Title of Invention: HEAT GENERATING STRUCTURE AND HEAT GENERATING DEVICE Technical Field

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

[0002] In recent years, there has been proposed a heat generating device including a sealed container to which a hydrogen-containing gas is supplied, a heat generating element that generates heat by occluding and discharging hydrogen, and a columnar heater (see PTL 1). The heat generating element is a spirally wound heat generating element formed by spirally winding a plate-shaped member, and is disposed to cover a part of an outer peripheral surface of the heater. The heat generating element and the heater are accommodated in the sealed container. The heat generating element includes a base made 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 that is made of a hydrogen storage metal or a hydrogen storage alloy and has a thickness of less than 1,000 nm, and a second layer that is made of a hydrogen storage metal or a hydrogen storage alloy, which is different from that of the first layer, or ceramics and has a thickness of less than 1,000 nm. A heterogeneous material interface is formed between the first layer and the second layer. In the heat generating device disclosed in PTL 1, after hydrogen is occluded in the heat generating element, vacuum exhaust inside the sealed container and heating of the heat generating element are performed, so that hydrogen passes through a heterogeneous material interface by quantum diffusion, or hydrogen diffuses through the heterogeneous material interface by quantum diffusion to generate excess heat.

[0003] Meanwhile, the inventors of the present application have found that there is a correlation between a temperature of the heat generating element and the generation of excess heat, and the higher the temperature of the heat generating element, the more excess heat tends to be generated. When the temperature of the heat generating element is too high, the heat generating element reaches a melting point and is damaged, and therefore, when the heat generating element is heated by the heater, it is desired to make the temperature of the heat generating element uniform and high to such an extent that the heat generating element is not damaged. Citation List Patent Literature

[0004] PTL 1: WO2023 / 149220A1 Summary of Invention Technical Problem

[0005] In the heat generating element, a heat generation amount can be increased by increasing an area of the heat generating surface formed of a surface of the multilayer film. Since heat transfer due to convection of gas cannot be expected inside the vacuum exhausted sealed container, heat is transferred from the heater to the heat generating element by radiation, and heat is transferred from a high temperature side to a low temperature side inside the heat generating element by heat conduction. Therefore, as the area of the heat generating surface of the heat generating element is increased, there is a problem that a temperature difference is likely to occur between the high temperature side and the low temperature side of the heat generating element. In a case where a plurality of heat generating elements are disposed in the sealed container, there is a problem that the heat generating surfaces of the heat generating elements come into contact with each other, causing a decrease in the heat generation amount and fusion of the heat generating elements due to thermal diffusion of the metal.

[0006] The heat generating device disclosed in Patent Literature 1 is configured such that an outer peripheral surface of a columnar heater is surrounded by a wound heat generating element, and is configured such that the wound heat generating element can be efficiently heated by the heater. However, in the heat generating device disclosed in Patent Literature 1, since radiant heat from the heater is not easily transferred to the outer periphery of the wound heat generating element in a spiral direction, a temperature difference is generated between an inner periphery and an outer periphery in the spiral direction of the wound heat generating element, and it is  difficult to make the temperature distribution of the wound heat generating element uniform. As the number of turns of the wound heat generating element increases, the temperature difference between the inner periphery and the outer periphery of the wound heat generating element increases. Therefore, it is also difficult to increase the area of the heat generating surface.

[0007] An object of the present invention is to provide 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. Solution to Problem

[0008] A heat generating structure according to the present invention includes: a heat generating element 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 formed into a cylindrical shape and having an outer peripheral surface surrounded by the heat generating element, in which the multilayer film includes a first layer that is made of a hydrogen storage metal or a hydrogen storage alloy and has a thickness of less than 1,000 nm, and a second layer that is made of a hydrogen storage metal or a hydrogen storage alloy, which is different from that of the first layer, or ceramics and has a thickness of less than 1,000 nm, and the heat generating element includes an inner edge disposed to face the outer peripheral surface, an outer edge disposed farther away from the outer peripheral surface than the inner edge in a second direction orthogonal to a first direction along a central axis of the heater, and a heat generating surface connecting the inner edge and the outer edge and extending continuously in a circumferential direction around the central axis, and transfers heat from the inner edge to the outer edge by heat conduction.

[0009] A heat generating device according to the present invention includes:  the heat generating structure described above; a sealed container accommodating the heat generating structure therein; a supply unit configured to supply a hydrogen-based gas containing the hydrogen into the sealed container; and a discharge unit configured to discharge the hydrogen-based gas inside the sealed container. Advantageous Effects of Invention

[0010] According to the present invention, a temperature distribution of a heat generating element can be made uniform, and an area of a heat generating surface can be increased. Brief Description of Drawings FIG. 1 is a conceptual diagram schematically illustrating a configuration of a heat utilization system according to a first embodiment. FIG. 2 is an exploded perspective view illustrating a heat generating structure according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a heat generating element. FIG. 4 is a graph illustrating temperature distribution of the heat generating structure according to the first embodiment. FIG.  5 is an exploded perspective view illustrating a heat generating structure according to a second embodiment. FIG.  6 is a conceptual diagram schematically illustrating a configuration of a heat utilization system according to a third embodiment. FIG. 7 is a schematic cross-sectional view illustrating a heat generating structure taken along a line VII-VII in FIG. 6. FIG. 8 is an exploded perspective view illustrating a heat generating structure according to the third embodiment. FIG. 9 is a graph illustrating temperature distribution of the heat generating structure according to the third embodiment. FIG. 10 is a conceptual diagram schematically illustrating a configuration of a heat utilization system according to a fourth embodiment. FIG. 11 is a conceptual diagram schematically illustrating a configuration of a heat utilization system according to a fifth embodiment. FIG. 12 is a conceptual diagram schematically illustrating a configuration of a heat utilization system according to a sixth embodiment. Description of Embodiments

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description and drawings, common components are given common reference numerals. Descriptions of the configurations given common reference numerals will be omitted as appropriate.

[0013] (1) Heat Utilization System according to First Embodiment In FIG. 1, a 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 in 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 medium may be a gas or liquid, and is preferably one that has excellent thermal conductivity and is chemically stable. Examples of the gas include helium gas, argon gas, hydrogen gas, nitrogen gas, water vapor, air, and carbon dioxide. Examples of the liquid include water, molten salts (e.g. KNO3 (40%) - NaNO3 (60%)), and a liquid metal (e.g. Pb). A multiphase heat medium in which solid particles are dispersed in a gas or liquid may be used as the heat medium. The solid particles are metals, metal compounds, alloys, ceramics, or the like. Examples of the metals include Cu, Ni, Ti, and Co. Examples of the metal compounds include oxides, nitrides, and silicides of the above metals. Examples of the alloys include stainless steel and chrome molybdenum steel. Examples of the ceramics include alumina. The helium gas is used as the heat medium in the present embodiment, but it can be appropriately changed without departing from the scope of the present invention.

[0015] The heat generating device 3 includes 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 accommodated in the sealed container 5.

[0016] The sealed container 5 has heat resistance and pressure resistance. The sealed container 5 is made of, for example, stainless steel or heat-resistant non-ferrous alloy steel. Examples of a material used for the sealed container 5 include a material used according to an operating temperature, stainless steel used when the operating temperature is up to about 700°C, and heat-resistant non-ferrous alloy steel used when the operating temperature exceeds 700°C. The sealed container 5 is formed into a cylindrical shape. The sealed container 5 includes a body, an upper lid provided at an upper end of the body, and a lower lid provided at a lower end of the body. The upper end of the body is airtightly closed by the upper lid, and the lower end of the body is airtightly closed by the lower lid, whereby a space 9 is defined inside the sealed container 5. A shape of the sealed container 5 is not limited to the cylindrical shape, and may be an elliptical cylindrical shape, a polygonal cylindrical shape, a spherical shape, or the like. In the heat generating device 3, an upper lid side of the sealed container 5 is referred to as an upper side, and a lower lid side of the sealed container 5 is referred to as a lower side.

[0017] The heat generating device 3 includes an introduction pipe 10 connecting the sealed container 5 and the hydrogen tank 6, and an exhaust pipe 11 connecting the sealed container 5 and the vacuum pump 7. The introduction pipe 10 extends from the lower lid of the sealed container 5 and is coupled to the hydrogen tank 6, and constitutes an introduction path for guiding the hydrogen-based gas stored in the hydrogen tank 6 to the space 9 inside the sealed container 5. The exhaust pipe 11 extends from the upper lid of the sealed container 5 and is coupled to the vacuum pump 7, and constitutes an exhaust path for guiding the hydrogen-based gas suctioned from the space 9 inside the sealed container 5 to the vacuum pump 7.

[0018] The introduction pipe 10 includes a supply valve 12 provided between the sealed container 5 and the hydrogen tank 6. The supply valve 12 adjusts a flow rate of the hydrogen-based gas flowing through the introduction pipe 10. As the supply valve 12, for example, an electromagnetic valve or an air valve is used. The introduction pipe 10 may include a pressure sensor that detects a pressure of the hydrogenbased gas flowing through the introduction pipe 10.

[0019] The exhaust pipe 11 includes an exhaust valve 13 provided between the sealed container 5 and the vacuum pump 7. The exhaust valve 13 adjusts a flow rate of the hydrogen-based gas flowing through the exhaust pipe 11. As the exhaust valve 13, for example, an electromagnetic valve or an air valve is used. The exhaust pipe 11 may include a pressure sensor that detects a 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, the hydrogen-based gas can be supplied 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, the hydrogen-based gas in the space 9 inside the sealed container 5 can be discharged by the vacuum pump 7.

[0021] The hydrogen tank 6 stores the 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 space 9 inside the low-pressure sealed container 5 through the introduction pipe 10. The hydrogen-based gas is a gas containing isotopes of hydrogen. As the hydrogen-based gas, at least one of a deuterium gas and a protium gas is used. The protium gas includes a mixture of naturally occurring protium and deuterium, that is, a mixture in which an abundance ratio of protium is 99.985% and an abundance ratio of deuterium is 0.015%. The introduction pipe 10 may include a pump that feeds the hydrogenbased gas stored in the hydrogen tank 6 to the space 9 inside the sealed container 5.

[0022] The vacuum pump 7 discharges 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 includes, for example, a turbo molecular pump and a dry pump. The turbo molecular pump adjusts a rotation speed of turbine blades based on a control signal input from a control unit 21 to be described later. A speed of depressurization of the space 9 is adjusted according to the rotation speed of the turbo molecular pump.

[0023] The heat generating structure 8 heats the heat medium flowing along an outer surface of the sealed container 5 via the sealed container 5. A temperature of the heat medium heated by the heat generating structure 8 reaches, for example, a range of 50°C or more and 1500°C or less. In this example, the temperature of the heat medium is set to 700°C.

[0024] The heat generating structure 8 includes heat generating element 14 that generate heat by occluding and discharging hydrogen, a heater 15 that heats each of the heat generating elements 14, and a temperature sensor 17 that detects a temperature of the heat generating element 14.

[0025] The heat generating element 14 is formed into a plate shape having a through hole. In the present embodiment, the heat generating element 14 is formed into an annular shape and has a circular through hole at the center. The heater 15 is disposed in the through hole of the heat generating element 14. A plurality of heat generating elements 14 are disposed in the first direction along a central axis CL (see FIG. 2) of the heater 15. That is, the heat generating structure 8 includes the plurality of heat generating elements 14 disposed in the first direction. Each of the heat generating elements 14 is not limited to an annular shape, and may be a polygonal annular shape or the like. A configuration of the heat generating element 14 will be described later with reference to another drawing.

[0026] The heater 15 is formed into a hollow or solid cylindrical shape. In the present embodiment, the heater 15 is formed into a solid cylindrical shape and has a uniform diameter over the entire length in the first direction along the central axis CL. The term “uniform” includes not only a case of being strictly uniform but also a case of being substantially uniform, that is, a case of being different without departing from the spirit of the invention. A shape of the heater 15 is not limited to a cylindrical shape, and may be another appropriate shape such as an elliptical cylindrical shape or a polygonal cylindrical shape. As the heater 15 of the cylindrical shape, a sheath heater, a ceramic heater, a lamp heater, or the like is used. For example, a sheath heater has a configuration in which a spirally wound heating wire is accommodated in a metal pipe. In the pipe, the heating wire is disposed at a portion other than portions at a predetermined distance from both ends in an axial direction of the pipe. A pair of terminals connected to a power supply 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 supply 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 heat generating element 14. The outer peripheral surface 15a is a cylindrical surface in the present embodiment. The heater 15 generates radiant heat from the outer peripheral surface 15a.

[0028] The heater 15 includes a pair of electrodes 20. The pair of electrodes 20 are connected to a conductive wire 18. The conductive wire 18 is connected to a power supply 19, and electrically connects the pair of electrodes 20 and the power supply 19. In the heater 15, a temperature of the outer peripheral surface 15a is increased by supplying electric power from the power supply 19 through the conductive wire 18 and the pair of electrodes 20. The heater 15 heats the heat generating element 14 by the radiant heat generated from the outer peripheral surface 15a. The pair of electrodes 20 are provided at both ends of the heater 15 in FIG. 1, or may be provided at one end or the other end of the heater 15. The pair of electrodes 20 extend from the inside to the outside of the sealed container 5 in FIG. 1, but may be accommodated inside the sealed container 5. For example, a pair of connection terminals may be provided on the upper lid and the lower lid of the sealed container 5, the pair of connection terminals may be connected to the conductive wire 18 outside the sealed container 5, and the pair of electrodes 20 may be connected to the pair of connection terminals inside the sealed container 5.

[0029] The temperature sensor 17 outputs a detection signal for specifying the detected temperature. The temperature sensor 17 includes, for example, a thermocouple embedded in the heat generating element 14. The thermocouple outputs a voltage for specifying the detected temperature.

[0030] The heat generating device 3 includes the 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 implements arithmetic processing based on an application program stored in a read-only memory (ROM) or another storage unit, and a random access memory (RAM) that temporarily stores programs and data used for the arithmetic processing.

[0031] The control unit 21 outputs control signals for controlling respective 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, thereby discharging (vacuum exhausting) the hydrogen-based gas from the space 9 inside the sealed container 5.

[0033] The control unit 21 stops driving 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 supply 19 to adjust a magnitude of the electric power supplied from the power supply 19 to the heater 15 via the conductive wire 18 and the pair of electrodes 20. By controlling the output of the power supply 19, the temperature of the heat generating element 14 heated by the heater 15 is adjusted, and the heat generating element 14 can be maintained within a temperature range optimal for heat generation (for example, 50°C to 1500°C).

[0035] In the heat generating device 3, the hydrogen tank 6, the introduction pipe 10, and the supply valve 12 constitute a supply unit 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 a discharge unit that discharges the hydrogen-based gas inside the sealed container 5.

[0036] The heat utilization device 4 includes a storage container 41 that stores the sealed container 5 of the heat generating device 3, a first power generation unit 42 that generates power based on a heat medium (helium gas in this example) heated by the heat generating device 3 inside the storage container 41, a pressure pump 43 that sends the heat medium from the first power generation unit 42 toward the storage container 41, and a flow rate control valve 44 that is provided between the pressure pump 43 and the storage container 41.

[0037] The storage container 41 has thermal insulation and pressure resistance. The storage container 41 is made of, for example, stainless steel or heat-resistant non-ferrous alloy steel. Examples of a material used for the storage container 41 include a material used according to an operating temperature, stainless steel used when the operating temperature is up to about 700°C, and heat-resistant non-ferrous alloy steel used when the operating temperature exceeds 700°C. The storage container 41 has an inflow port 41a through which the heat medium flows and an outflow port 41b through which the heat medium flows out. The heat medium flowing into the storage container 41 through the inflow port 41a flows along the outer surface of the sealed container 5 of the heat generating device 3 stored in the storage container 41, and is heated by the heat generating structure 8 accommodated in the sealed container 5. The temperature of the heat medium rises inside the storage container 41, and a high-temperature heat medium is obtained. The high-temperature heat medium flows out from the outflow port 41b of the storage container 41 and flows into the first power generation unit 42.

[0038] The first power generation unit 42 includes a compressor (not illustrated) that compresses the high-temperature heat medium supplied from the storage container 41, a gas turbine 42a that is driven based on a high-temperature and high-pressure heat medium compressed by the compressor, and an electric generator 42b coupled to the gas turbine 42a. In the first power generation unit 42, the temperature of the heat medium is adjusted within a range of, for example, 600°C or more and 1,500°C or less. An output shaft of the gas turbine 42a is coupled to an input shaft of the electric generator 42b. When turbine blades of the gas turbine 42a rotate, a rotor of the electric generator 42b is driven, and electric power is generated (power generation is performed) by the electric generator 42b. The heat medium, in which heat has been utilized in the first power generation unit 42, flows out of the first power generation unit 42 and flows into the pressure pump 43.

[0039] The pressure pump 43 sends the heat medium supplied from the first power generation unit 42 toward the storage container 41 at a predetermined pressure. Examples of the pressure pump 43 include a metal bellows pump.

[0040] The flow rate control valve 44 adjusts the flow rate of the heat medium flowing from the pressure pump 43 toward the storage container 41. As the flow rate control valve 44, for example, a variable leak valve is used.

[0041] FIG. 2 is an exploded perspective view illustrating the heat generating structure 8 according to the first embodiment. As illustrated in FIG. 2, each of the heat generating elements 14 includes an inner edge 51 disposed to face the outer peripheral surface 15a of the heater 15, an outer edge 52 disposed farther away from the outer peripheral surface 15a than the inner edge 51 in a second direction orthogonal to a first direction along the central axis CL of the heater 15, and a 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 inner edge 51 and the outer edge 52 extend continuously in the circumferential direction around the central axis CL of the heater 15. The heat generating surface 53 is disposed in a plane orthogonal to the first direction along the central axis CL of the heater 15. The term “continuously” refers to being continuous in the circumferential direction around the central axis CL. The second direction is a radiation direction (also referred to as a radial direction) around the central axis CL.

[0042] The inner edge 51 is disposed over one circumference in the circumferential direction. The through hole of the heat generating element 14 is formed in the inner edge 51. The inner edge 51 is provided at a position away from the outer peripheral surface 15a of the heater 15 in the second direction. A gap is formed between the inner edge 51 of the heat generating element 14 and the outer peripheral surface 15a of the heater 15. A diameter of the inner edge 51 is larger than a diameter of the heater 15. The diameter of the inner edge 51 is an inner diameter of the heat generating element 14. For example, when the heat generating element 14 has a polygonal annular shape, the inner diameter of the heat generating element 14 is a diameter of an inscribed circle of the inner edge 51.

[0043] The outer edge 52 is disposed over one circumference in the circumferential direction. The outer edge 52 is provided at a position away from an inner surface of the sealed container 5 (an inner surface of the body) in the second direction. A gap is formed between the outer edge 52 of the heat generating element 14 and the inner surface of the sealed container 5. A diameter of the outer edge 52 is smaller than an inner diameter of the sealed container 5. The inner diameter of the sealed container 5 is a diameter of the inner surface of the body. The diameter of the outer edge 52 is an outer diameter of the heat generating element 14. For example, when the heat generating element 14 has a polygonal annular shape, the outer diameter of the heat generating element 14 is a diameter of a circumscribed circle of the outer edge 52.

[0044] The heat generating surface 53 extends continuously from the inner edge 51 to the outer edge 52. That is, the heat generating surface 53 continuously extends in the second direction orthogonal to the first direction. The heat generating surface 53 is formed into an annular shape. The heat generating surface 53 is a surface of a multilayer film 62 (see FIG. 3) to be described later. The larger an area of the heat generating surface 53, the greater the heat generation amount generated by the heat generating element 14. The heat generation amount of the heat generating element 14 is the amount of heat generated when hydrogen atoms permeate through heterogeneous material interfaces 73 to be described later by quantum diffusion or when hydrogen atoms diffuse through the heterogeneous material interfaces 73 by quantum diffusion.

[0045] The heat generating element 14 receives the radiant heat generated from the outer peripheral surface 15a of the heater 15 at the inner edge 51. A temperature of the inner edge 51 rises by the radiant heat from the outer peripheral surface 15a of the heater 15. The heat of the inner edge 51 is transferred to the outer edge 52 by heat conduction. That is, the heat generating element 14 transfers heat from the inner edge 51 to the outer edge 52 by heat conduction. The temperature of the outer edge 52 rises by heat conduction from the inner edge 51. Accordingly, the temperature difference between the inner edge 51 and the outer edge 52 is reduced, and the temperature distribution of the heat generating element 14 is made uniform.

[0046] The heat generating structure 8 includes a spacer 55 provided between adjacent heat generating elements 14 among the plurality of heat generating elements 14 disposed in the first direction. The spacer 55 is formed of a material having heat resistance and pressure resistance. The spacer 55 forms a space between adjacent heat generating elements 14 to prevent contact between the adjacent heat generating elements 14. The spacer 55 positions the plurality of heat generating elements 14 in the first direction.

[0047] The spacer 55 abuts on the outer peripheral surface 15a of the heater 15. The spacer 55 is formed into an annular shape. The heater 15 is inserted into an opening formed by the inner edge of the spacer 55. The inner edge of the spacer 55 abuts on the outer peripheral surface 15a of the heater 15, so that the spacer 55 is fixed to the outer peripheral surface 15a of the heater 15. In the present embodiment, the spacer 55 is formed into an annular shape. The spacer 55 is not limited to an annular shape, and may be a polygonal annular shape or the like.

[0048] Next, the configuration of the heat generating element 14 will be described. FIG. 3 is a cross-sectional view illustrating a configuration of the heat generating element 14. As illustrated in FIG. 3, the heat generating 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 first layers 71, each of which is made of a hydrogen storage metal or a hydrogen storage alloy and has a thickness of less than 1,000 nm, and second layers 72, each of which is made of a hydrogen storage metal or a hydrogen storage alloy, which is different from that of the first layer 71, or ceramics and has a thickness of less than 1,000 nm. The heterogeneous material interfaces 73 are formed between the first layer 71 and the second layer 72 and between the support 61 and the multilayer film 62. Hydrogen atoms permeate through the heterogeneous material interface 73. The heat generating element 14 generates excess heat when the hydrogen atoms permeate through the heterogeneous material interfaces 73 by quantum diffusion, or when the hydrogen atoms diffuse through the heterogeneous material interfaces 73 by quantum diffusion. As the heat generating element 14, heat generating elements disclosed in WO2018 / 230447A1, WO2020 / 122097A1, WO2020 / 122098A1, and the like can be used. The detailed configuration, function, and manufacturing method of the heat generating element 14 are the same as those disclosed in WO2018 / 230447A1, WO2020 / 122097A1, WO2020 / 122098A1, and the like, and thus the description thereof is omitted here.

[0049] In FIG. 3, the multilayer film 62 is stacked on one surface (for example, a front surface) of the support 61, but is not limited thereto. The multilayer film 62 may be stacked on the other surface (for example, a back surface) of the support 61, or the multilayer film 62 may be stacked on both surfaces (the front surface and the back surface) of the support 61.

[0050] Functions and effects of the heat generating device 3 according to the present embodiment will be described. First, the sealed container 5 is opened, the heat generating structure 8 is disposed inside the sealed container 5, and the sealed container 5 is sealed. The pair of electrodes 20 of the heat generating structure 8 are connected to the power supply 19 via the conductive wire 18. The exhaust valve 13 is opened, and the vacuum pump 7 is driven. The space 9 inside the sealed container 5 is vacuum-exhausted. The driving of the vacuum pump 7 is stopped, the exhaust valve 13 is closed, and the power supply 19 is driven. Electric power is supplied from the power supply 19 to the heater 15 via the conductive wire 18 and the pair of electrodes 20. When electric power is supplied to the heater 15, the temperature of the outer peripheral surface 15a rises. The heat generating element 14 receives the radiant heat generated from the outer peripheral surface 15a of the heater 15 at the inner edge 51. The temperature of the inner edge 51 rises by the radiant heat from the outer peripheral surface 15a of the heater 15. In the heat generating element 14, the inner edge 51 and the outer edge 52 are continuously connected to the heat generating surface 53, and heat of the inner edge 51 is transferred to the outer edge 52 by heat conduction. The temperature of the outer edge 52 rises by the heat conduction from the inner edge 51. The temperature difference between the inner edge 51 and the outer edge 52 is reduced, and the temperature distribution of the heat generating element 14 is made uniform. In this way, the temperature of the heat generating element 14 can be uniformly increased to a specific temperature. For example, the temperature of the heat generating element 14 is about 200°C, thereby removing moisture from the heat generating element 14.

[0051] Next, the output of the power supply 19 is increased, and the temperature of the heat generating element 14 further rises. For example, the temperature of the heat generating element 14 is about 300°C. The supply valve 12 is opened. The 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 heat generating element 14 stores hydrogen. Specifically, a hydrogen molecule in the space 9 is adsorbed on a front surface of the multilayer film 62 of the heat generating element 14 (surface opposite to the support 61), and the hydrogen molecule is dissociated into two hydrogen atoms. The hydrogen atoms obtained by dissociation penetrate (are stored) into the multilayer film 62.

[0052] After the hydrogen is occluded in the heat generating element 14, the supply valve 12 is closed. The output of the power supply 19 is controlled to set the temperature of the heat generating element 14 to any temperature within an optimum temperature range for heat generation (for example, about 700°C). At this time, the exhaust valve 13 is opened, and the vacuum pump 7 is driven. The hydrogen-based gas is discharged from the space 9 inside the sealed container 5. The heat generating element 14 discharges the hydrogen. Specifically, the hydrogen atoms penetrating into the multilayer film 62 are returned to the front surface of the multilayer film 62 and are recombined to be discharged as the hydrogen molecules. As a result, the heat generating element 14 generates excess heat when the hydrogen atoms permeate through the heterogeneous material interfaces 73 by quantum diffusion, or when the hydrogen atoms diffuse through the heterogeneous material interfaces 73 by quantum diffusion.

[0053] In the heat generating structure 8 according to the present embodiment, the inner edge 51 and the outer edge 52 of the heat generating element 14 are connected to the 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 the radiant heat generated from the outer peripheral surface 15a of the heater 15. At this time, in the heat generating element 14, heat of the inner edge 51 is transferred to the outer edge 52 by heat conduction. Accordingly, heat is transferred to the entire heat generating element 14, and the temperature difference between the inner edge 51 and the outer edge 52 of the heat generating element 14 is reduced. Accordingly, the heat generating structure 8 can make the temperature distribution of the heat generating element 14 uniform.

[0054] FIG. 4 illustrates results obtained by analyzing the temperature distribution of the heat generating structure 8. In the cross-section including the central axis CL of the heater 15 and the inner edge 51 and the outer edge 52 of the heat generating element 14, a temperature from the central axis CL of the heater 15 to the inner surface of the sealed container 5 was analyzed. A simulation of heat conduction and radiation was performed using commercially available thermal analysis software. The electric power supplied from the power supply 19 to the heater 15 was 400W. In FIG. 4, a horizontal axis indicates a position in a radial direction (radiation direction) around the central axis CL of the heater 15, and a vertical axis indicates a temperature. From FIG. 4, it was confirmed that the temperature of the inner edge 51 and the temperature of the outer edge 52 of the heat generating element 14 were about 550°C and the temperature distribution of the heat generating element 14 was uniform. Since the inner edge 51 and the outer edge 52 of the heat generating element 14 are continuously connected to the heat generating surface 53, heat is transferred to the entire heat generating element 14, and the temperature difference between the inner edge 51 and the outer edge 52 is reduced.

[0055] In the heat generating structure 8, since the plurality of heat generating elements 14 are disposed in the first direction, the total area obtained by adding the areas of the heat generating surfaces 53 increases, and the heat generation amount increases. In the heat generating structure 8, the total area of the heat generating surfaces 53 can be easily increased only by increasing the number of heat generating elements 14. In the heat generating structure 8, the heat generation amount can be easily increased or decreased by changing the number of heat generating elements 14.

[0056] Since the heat generating structure 8 includes the spacer 55 provided between adjacent heat generating elements 14 among the plurality of heat generating elements 14 disposed in the first direction, a space is formed between the adjacent heat generating elements 14, and contact between the adjacent heat generating elements 14 is prevented. Accordingly, a decrease in the heat generation amount due to contact between the heat generating surfaces 53 of the heat generating elements 14 and fusion between the heat generating elements 14 due to thermal diffusion of metal are prevented. Each heat generating element 14 is more efficiently heated by the radiant heat from the adjacent heat generating element 14, and can reach an optimum temperature for heat generation in a shorter time.

[0057] Functions and effects of the heat utilization system 1 according to the present embodiment will be described. In the piping path 2, the helium gas as a heat medium flows into the storage container 41 by the pressure pump 43. In the storage container 41, the heat is transferred from the heat generating device 3 to the helium gas, and the temperature of the helium gas rises. A high-temperature helium gas flowing out of the storage container 41 flows into the compressor (not illustrated) of the first power generation unit 42. A high-temperature and high-pressure helium gas flowing out of the compressor flows into the gas turbine 42a to cause the turbine blades of the gas turbine 42a to rotate. The rotation of the turbine blades is transferred to the rotor of the electric generator 42b. The electric power is generated by the electric generator 42b.

[0058] Heat energy of the helium gas is consumed in the rotation of the turbine blades of the gas turbine 42a. A pressure decreases as the temperature of the helium gas decreases in the gas turbine 42a. The helium gas flowing out of the gas turbine 42a is drawn into the pressure pump 43. The helium gas is sent out from the pressure pump 43 toward the storage container 41. The electric power generation is continued in accordance with the circulation of the helium gas.

[0059] As described above, the heat utilization system 1 uses, as a heat source, a heat medium heated by the heat generating device 3 including the heat generating element 14 that generates heat by occluding and discharging hydrogen, and thus can supply energy inexpensively, cleanly, and safely.

[0060] In the heat utilization system 1, since the heat generating element 14 is provided to cover the outer peripheral surface 15a around the heater 15, the sealed container 5 is provided to cover the heat generating element 14, and the storage container 41 is provided to cover the sealed container 5, the heat generating element 14 can be more efficiently heated by the heater 15, and the heat medium can be more efficiently heated by the heat generating element 14.

[0061] (2) Heat Generating Structure according to Second Embodiment In the first embodiment, the spacer 55 is provided between adjacent heat generating elements 14 among the plurality of heat generating elements 14 disposed in the first direction. In the second embodiment, in addition to the spacer, a pair of end members is provided adjacent to the heat generating element 14 disposed at an end in the first direction.

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

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

[0064] The heat generating structure 8a includes spacers 75 each provided between adjacent heat generating elements 14 among the plurality of heat generating elements 14 disposed along the first direction, and a pair of end members 76 provided adjacent to the heat generating element 14 disposed at the end in the first direction among the plurality of heat generating elements 14 disposed in the first direction.

[0065] Each of the spacers 75 is formed of a material having heat resistance and pressure resistance. The spacer 75 forms a space between adjacent heat generating elements 14. The spacer 75 prevents contact between adjacent heat generating elements 14. The spacer 75 positions the plurality of heat generating elements 14 in the first direction. The spacer 75 includes a first frame 78 and first protrusions 79.

[0066] The first frame 78 is disposed away from the outer peripheral surface 15a of the heater 15 in the second direction. The first frame 78 is formed into an annular shape. The heater 15 is inserted into an opening formed by an inner edge of the first frame 78. A gap is formed between the inner edge of the first frame 78 and the outer peripheral surface 15a of the heater 15. An inner diameter of the first frame 78 is an inner diameter of the spacer 75, and an outer diameter of the first frame 78 is an outer diameter of the spacer 75. The outer diameter of the first frame 78 is larger than the outer diameter of the heat generating element 14. In the present embodiment, the first frame 78 is formed into an annular shape. The first frame 78 is not limited to an annular shape, and may be a polygonal annular shape or the like.

[0067] The first protrusions 79 protrude from the first frame 78 in the first direction and abut on the outer edges 52 of the heat generating elements 14. Each of the first protrusions 79 includes a plurality of first pins arranged at intervals in the circumferential direction. Inner edges of the plurality of first pins abut on the outer edges 52 of the heat generating elements 14.

[0068] The pair of end members 76 sandwich the plurality of heat generating elements 14 and a plurality of spacers 75 from the first direction. The pair of end members 76 have the same configuration. Each of the end members 76 includes an inner frame 81, an outer frame 82, coupling units 83, and second protrusions 84.

[0069] The inner frame 81 abuts on the outer peripheral surface 15a of the heater 15. The inner frame 81 is formed into an annular shape. The heater 15 is inserted into an opening formed by an inner edge of the inner frame 81. The inner frame 81 fixes the end member 76 to the outer peripheral surface 15a of the heater 15 by the inner edge of the inner frame 81 abutting on the outer peripheral surface 15a of the heater 15. In the present embodiment, the inner frame 81 is formed into an annular shape. The inner frame 81 is not limited to an annular shape, and may be a polygonal annular shape or the like.

[0070] The outer frame 82 is disposed further away from the outer peripheral surface 15a of the heater 15 than the inner frame 81 in the second direction. The outer frame 82 is formed into an annular shape. The inner frame 81 is disposed in an opening formed by an inner edge of the outer frame 82. In the present embodiment, the outer frame 82 is formed into an annular shape. The outer frame 82 is not limited to an annular shape, and may be a polygonal annular shape or the like.

[0071] The coupling units 83 couple the inner frame 81 and the outer frame 82. A plurality of coupling units 83 are arranged at intervals in the circumferential direction. That is, each of the end members 76 includes a plurality of coupling units 83 that couple the inner frame 81 and the outer frame 82, and has a configuration in which the plurality of coupling units 83 are arranged at intervals in the circumferential direction. Gaps are formed between the plurality of coupling units 83. In FIG. 5, the four coupling units 83 are disposed to extend radially around the central axis CL of the heater 15.

[0072] The second protrusions 84 protrude from the outer frame 82 in the first direction and abut on the outer edges 52 of the heat generating elements 14. Each of the second protrusions 84 includes a plurality of second pins arranged at intervals in the circumferential direction. Inner edges of the plurality of second pins abut on the outer edges 52 of the heat generating elements 14.

[0073] In the heat generating structure 8a according to the second embodiment, the inner edge 51 and the outer edge 52 of each of the heat generating element 14 are connected to the 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 the radiant heat generated from the outer peripheral surface 15a of the heater 15. At this time, in the heat generating element 14, the heat of the inner edge 51 is transferred to the outer edge 52 by heat conduction. Accordingly, heat is transferred to the entire heat generating element 14, and the temperature difference between the inner edge 51 and the outer edge 52 of the heat generating element 14 is reduced. Accordingly, the heat generating structure 8a can make the temperature distribution of the heat generating element 14 uniform.

[0074] In the heat generating structure 8a, since the plurality of heat generating elements 14 are disposed in the first direction, the total area of the heat generating surfaces 53 increases and the heat generation amount increases. In the heat generating structure 8a, the heat generation amount can be adjusted according to the number of heat generating elements 14.

[0075] In the heat generating structure 8a, since the spacer 75 is provided between the adjacent heat generating elements 14 among the plurality of heat generating elements 14 disposed in the first direction, a space is formed between the adjacent heat generating elements 14, and contact between the adjacent heat generating elements 14 is prevented. Accordingly, a decrease in the heat generation amount due to contact between the heat generating surfaces 53 of the heat generating elements 14 and fusion between the heat generating elements 14 due to thermal diffusion of metal are prevented. Each heat generating element 14 is more efficiently heated by the radiant heat from the adjacent heat generating element 14, and can reach an optimum temperature for heat generation in a shorter time.

[0076] The heat generating structure 8a includes, in addition to the spacer 75, a pair of end members 76 provided adjacent to the heat generating element 14 disposed at an end in the first direction among the plurality of heat generating elements 14 disposed in the first direction. In the heat generating structure 8a, the first protrusions 79 of the spacers 75 abut on the outer edges 52 of the heat generating elements 14, the second protrusions 84 of the end members 76 abut on the outer edges 52 of the heat generating elements 14, and the end members 76 are fixed to the outer peripheral surface 15a of the heater 15 by the inner frame 81. Therefore, the plurality of heat generating elements 14, the heater 15, the plurality of spacers 75, and the pair of end members 76 are integrated. Accordingly, the plurality of heat generating elements 14, the plurality of spacers 75, and the pair of end members 76 are positioned in the first direction and the second direction with respect to the heater 15.

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

[0078] FIG. 6 is a conceptual diagram schematically illustrating a configuration of a heat utilization system 1a according to the third embodiment. The heat utilization system 1a includes a heat generating device 3a instead of the heat generating device 3 according to the first embodiment. The heat generating device 3a is incorporated into the piping path 2 together with the heat utilization device 4. The same or equivalent components and members as those of the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[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 occluding and discharging hydrogen, the heater 15 that heats the heat generating element 14a, and the temperature sensor 17 that detects a temperature of the heat generating element 14a.

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

[0081] A specific shape of the heat generating element 14a will be described with reference to FIG. 7. FIG. 7 is a schematic crosssectional view illustrating the heat generating structure 8b taken along a line VII-VII in FIG. 6. As illustrated in FIG. 7, the heat generating element 14a has a configuration in which the heat generating element 14a is alternately folded a plurality of times on an inner side and an outer side around the central axis CL of the heater 15, and both ends thereof are connected to each other. The heat generating element 14a has a shape (also referred to as a star shape) continuously extending in a zigzag shape in the circumferential direction around the central axis CL in a plan view viewed from the first direction.

[0082] The heat generating element 14a includes inner edges 91 each disposed to face the outer peripheral surface 15a of the heater 15, outer edges 92 each disposed farther away from the outer peripheral surface 15a than the inner edge 91 in a second direction orthogonal to the first direction along the central axis CL, and a heat generating surface 93 connecting the inner edges 91 and the outer edges 92 and extending continuously in the circumferential direction around the central axis CL. A plurality of inner edges 91 and a plurality of outer edges 92 are disposed intermittently in the circumferential direction around the central axis CL. The heat generating surface 93 extends continuously while being alternately folded a plurality of times in the circumferential direction around the central axis CL. The term “intermittently” refers to being not continuous in the circumferential direction around the central axis CL. That is, the heat generating element 14a includes the plurality of inner edges 91 disposed intermittently in the circumferential direction, the plurality of outer edges 92 disposed intermittently in the circumferential direction, and the heat generating surface 93 extending continuously while being alternately folded a plurality of times in the circumferential direction.

[0083] The inner edge 91 constitutes a folded portion inside the heat generating element 14a. The inner edge 91 extends in the first direction. The inner edge 91 is provided at a position away from the outer peripheral surface 15a of the heater 15 in the second direction. A gap is formed between the inner edge 91 and the outer peripheral surface 15a.

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

[0085] The heat generating surface 93 is folded outward (toward the outer edge 92) at the inner edge 91 and folded inward (toward the inner edge 91) at the outer edge 92. The heat generating surface 93 includes first surfaces 93a and second surfaces 93b inclined with respect to a virtual plane 94 orthogonal to the outer peripheral surface 15a of the heater 15. In FIG. 7, the virtual plane 94 is indicated by a two-dot chain line. The first surfaces 93a and the second surfaces 93b are disposed symmetrically with respect to the virtual plane 94. A plurality of first surfaces 93a and a plurality of second surfaces 93b are alternately disposed in the circumferential direction around the central axis CL. A space is formed between the first surface 93a and second surface 93b adjacent to each other. The first surface 93a and the second surface 93b adjacent to each other are disposed to face each other, and are coupled to each other by the inner edge 91 or the outer edge 92. The plurality of first surfaces 93a and the plurality of second surfaces 93b are alternately coupled at the inner edge 91 and the outer edge 92 to form the heat generating surface 93 as one continuous body. The heat generating surface 93 is disposed over one circumference in the circumferential direction around the central axis CL.

[0086] The heat generating element 14a receives radiant heat generated from the outer peripheral surface 15a of the heater 15 at the inner edge 91. A temperature of the inner edge 91 rises by the radiant heat from the outer peripheral surface 15a of the heater 15. The heat of the inner edge 91 is transferred to the outer edge 92 by heat conduction. That is, the heat generating element 14a transfers heat from the inner edge 91 to the outer edge 92 by heat conduction. A temperature of the outer edge 92 rises by heat conduction from the inner edge 91. Accordingly, the temperature difference between the inner edge 91 and the outer edge 92 is reduced, and the temperature distribution of the heat generating element 14a is made uniform.

[0087] FIG. 8 is an exploded perspective view illustrating a heat generating structure 8b according to the third embodiment. As illustrated in FIG. 8, the heat generating structure 8b includes a holding unit 95 that holds the shape of the heat generating element 14a. The holding unit 95 is formed of a material having heat resistance and pressure resistance. The holding unit 95 maintains a space formed between the first surface 93a and the second surface 93b constituting the heat generating surface 93 of the heat generating element 14a, and prevents contact between the first surface 93a and the second surface 93b adjacent to each other.

[0088] The holding unit 95 includes support columns 96 fixed to the sealed container 5, a first guide unit 97 provided at one end of the support column 96, and a second guide unit 98 provided between one end and the other end of the support column 96. In the present embodiment, four support columns 96 are suspended from an upper lid of the sealed container 5. Each of the support columns 96 is not limited to the case of being suspended from the upper lid of the sealed container 5, and may be provided in a standing posture with respect to a lower lid of the sealed container 5. The support column 96 may be fixed to the body of the sealed container 5 to extend in the second direction.

[0089] The first guide unit 97 receives one end of the heat generating element 14a in the first direction. The first guide unit 97 is formed in a disk shape having an opening 97a at the center. The heater 15 is inserted into the opening 97a of the first guide unit 97.

[0090] The first guide unit 97 has a first groove 97b into which the one end of the heat generating element 14a in the first direction is fitted. The first groove 97b extends continuously while being alternately folded a plurality of times in the circumferential direction. The first groove 97b positions the one end of the heat generating element 14a in the first direction. A width of the first groove 97b is slightly larger than a thickness of the heat generating element 14a. A depth of the first groove 97b is not particularly limited. The first groove 97b may penetrate the first guide unit 97 in the first direction.

[0091] The second guide unit 98 receives the other end of the heat generating element 14a in the first direction. The second guide unit 98 is formed in a disk shape having an opening 98a at the center. The heater 15 is inserted into the opening 98a of the second guide unit 98.

[0092] The second guide unit 98 has a second groove 98b into which the other end of the heat generating element 14a in the first direction is fitted. The second groove 98b extends continuously while being alternately folded a plurality of times in the circumferential direction. The second groove 98b positions the other end of the heat generating element 14a in the first direction. A width of the second groove 98b is slightly larger than a thickness of the heat generating element 14a. A depth of the second groove 98b is not particularly limited. The second groove 98b may penetrate the second guide unit 98 in the first direction.

[0093] In the heat generating structure 8b according to the third embodiment, the plurality of inner edges 91 and the plurality of outer edges 92 of the heat generating element 14a are intermittently disposed in the circumferential direction, and the heat generating surface 93 extends continuously while being alternately folded a plurality of times in the circumferential direction. Each of the inner edges 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, heat of the inner edge 91 is transferred to the outer edge 92 by heat conduction. Accordingly, heat is transferred to the entire heat generating element 14a, and the temperature difference between the inner edge 91 and the outer edge 92 of the heat generating element 14a is reduced. Accordingly, the heat generating structure 8b can make the temperature distribution of the heat generating element 14a uniform.

[0094] In the heat generating structure 8b, the plurality of first surfaces 93a and second surfaces 93b constituting the heat generating surface 93 of the heat generating element 14a are alternately disposed in the circumferential direction, and a space is formed between the first surface 93a and the second surface 93b adjacent to each other. Since the heat generating structure 8b can receive radiant heat from the outer peripheral surface 15a of the heater 15 over the entire heat generating surface 93 through the space, the temperature difference between the inner edge 91 and the outer edge 92 of the heat generating element 14a becomes smaller, and the temperature distribution of the heat generating element 14a can be made more uniform.

[0095] In the heat generating structure 8b, the first surface 93a and the second surface 93b are adjacent, and face each other. The first surface is more efficiently heated by radiant heat from the adjacent second surface 93b. The second surface 93b is more efficiently heated by radiant heat from the adjacent first surface 93a. Accordingly, the heat generating element 14a can reach an optimum temperature for heat generation in a shorter time.

[0096] The heat generating structure 8b includes the holding unit 95 that holds the shape of the heat generating element 14a. The holding unit 95 includes the first groove 97b into which one end of the heat generating element 14a in the first direction is fitted, and the second groove 98b into which the other end of the heat generating element 14a in the first direction is fitted. The first groove 97b and the second groove 98b extend continuously while being alternately folded a plurality of times in the circumferential direction around the central axis CL. The holding unit 95 maintains a space formed between the first surface 93a and the second surface 93b constituting the heat generating surface 93 of the heat generating element 14a, and prevents contact between the first surface 93a and the second surface 93b adjacent to each other. In the heat generating structure 8b, a decrease in the heat generation amount due to contact between the first surface 93a and the second surface 93b and fusion between the first surface 93a and the second surface 93b due to thermal diffusion of metal are prevented.

[0097] FIG. 9 illustrates results obtained by analyzing the temperature distribution of the heat generating structure 8b. In the cross-section including the central axis CL of the heater 15 and the outer edge 92 of the heat generating element 14a, a temperature from the central axis CL of the heater 15 to the inner surface of the sealed container 5 was analyzed. A simulation of heat conduction and radiation was performed using commercially available thermal analysis software. The electric power supplied from the power supply 19 to the heater 15 was 600W. In FIG. 9, a horizontal axis indicates a position in a radial direction (radiation direction) around the central axis CL of the heater 15, and a vertical axis indicates a temperature. In FIG. 9, a part of the graph from the central axis CL of the heater 15 to the outer peripheral surface 15a is omitted. Black squares indicate a temperature of the inner edge 91 and a temperature of the outer edge 92 of the heat generating element 14a. From FIG. 9, it was confirmed that the temperature of the inner edge 91 and the temperature of the outer edge 92 of the heat generating element 14a were about 600°C and the temperature distribution of the heat generating element 14a was uniform. It is considered that this result is attributable to the fact that the inner edge 91 and the outer edge 92 of the heat generating element 14a are continuously connected by the heat generating surface 93, heat is transferred to the entire heat generating element 14a, and the temperature difference between the inner edge 91 and the outer edge 92 is reduced.

[0098] (4) Heat Utilization System according to Fourth Embodiment FIG. 10 is a conceptual diagram schematically illustrating a configuration of a heat utilization system 1b according to a fourth embodiment. The heat utilization system 1b includes a heat utilization device 4a instead of the heat utilization device 4 according to the first embodiment. The heat utilization device 4a is incorporated in the piping path 2 together with the heat generating device 3. In the fourth embodiment, water is used as a heat medium. The same or equivalent components and members as those of the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0099] The heat utilization device 4a includes a boiler 101 that stores the sealed container 5 of the heat generating device 3, a second power generation unit 102 that generates electric power based on a 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 form 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 the pressurized liquid-phase heat medium toward the boiler 101.

[0100] The boiler 101 stores a pipe 105 that functions as an evaporator. Water is supplied from the water supply pump 104 to the pipe 105. The pipe 105 is exposed to the heat of the heat generating device 3. The heat is transferred from the sealed container 5 to the pipe 105. The boiler 101 generates high-temperature and high-pressure steam (gasphase heat medium) inside the pipe 105. The high-temperature and high-pressure steam is supplied from the boiler 101 to the second power generation unit 102.

[0101] The second power generation unit 102 includes a steam turbine 102a driven based on the high-temperature and high-pressure steam supplied from the boiler 101, and an electric generator 102b coupled to the steam turbine 102a. In the second power generation unit 102, the temperature of the steam is adjusted within a range of, for example, 300°C or more and 700°C or less. An output shaft of the steam turbine 102a is coupled to an input shaft of the electric generator 102b. When turbine blades of the steam turbine 102a rotate, a rotor of the electric generator 102b is driven, and electric power is generated by the electric generator 102b. The steam after the heat is used is supplied from the second power generation unit 102 to the condenser 103.

[0102] The condenser 103 cools the steam supplied from the second power generation unit 102 by cooling water 103a and returns the cooled steam to water (liquid-phase heat medium). The condenser 103 outputs low-pressure water. The low-pressure water is supplied from the condenser 103 to the water supply pump 104. The water supply 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 the heat generating device 3 including the heat generating element 14 that generates heat by occluding and discharging hydrogen, and thus can supply energy inexpensively, cleanly, and safely.

[0104] Instead of water, a substance that changes from a liquid phase to a gas phase according to the heat of the heat generating device 3 may be used as the heat medium. A substance that has excellent thermal conductivity and is chemically stable is preferably used as the heat medium.

[0105] (5) Heat Utilization System according to Fifth Embodiment FIG. 11 is a conceptual diagram schematically illustrating a configuration of a heat utilization system 1c according to a fifth embodiment. The heat utilization system 1c includes a heat utilization device 4b instead of the heat utilization device 4 according to the first embodiment. The heat utilization device 4b includes a Stirling engine 110 driven by receiving the heat from the heat generating device 3, and an electric generator 111 coupled to the Stirling engine 110. The same or equivalent components and members as those of the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0106] The Stirling engine 110 includes a first cylinder 112 having a closed end at one end, an expansion piston 114 accommodated in the first cylinder 112 at a position facing the closed end and defining an expansion chamber 113 between the expansion piston 114 and the closed end, a second cylinder 115 having a closed end at one end, a compression piston 117 accommodated in the second cylinder 115 at a position facing the closed end and defining a compression chamber 116 between the compression piston 117 and the closed end, a heater 118 connecting the expansion chamber 113 and the compression chamber 116 and receiving heat 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 crank shaft 122 serving as an output shaft individually coupled to the expansion piston 114 and the compression piston 117 by coupling rods 121a and 121b.

[0107] The crank shaft 122 (output shaft) of the Stirling engine 110 is coupled to an input shaft of the electric generator 111. When the crank shaft 122 rotates, a rotor of the electric generator 111 is driven, and electric power is generated by the electric generator 111.

[0108] The expansion piston 114 is displaced along an axial direction of the first cylinder 112 within 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. A reciprocating motion of the expansion piston 114 in an axial direction is converted into a rotational motion of the crank shaft 122. The expansion chamber 113 is sealed with a working fluid. Here, helium gas is used as the working fluid. In addition to the helium gas, a hydrogen-based gas or air may be used as the working fluid.

[0109] The compression piston 117 is displaced along an axial direction of the second cylinder 115 within 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 crank shaft 122 is converted into a reciprocating motion of the compression piston 117 in the axial direction. The compression chamber 116 is connected to the expansion chamber 113, and thus the compression chamber 116 is filled with the working fluid in the same manner as the expansion chamber 113. The working fluid flows between the expansion chamber 113 and the compression chamber 116 via the heater 118, the regenerator 120, and the 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 accommodated in the sealed container 5 and flows into the expansion chamber 113. The expansion chamber 113 expands in accordance with the expansion of the working fluid. The expansion piston 114 is displaced toward the crank shaft 122. A high-temperature and high- pressure working fluid flows into the regenerator 120 from the heater 118 in accordance with the contraction of the expansion chamber 113.

[0111] The cooler 119 cools the working fluid based on a cooling medium (not illustrated). For example, water is used as the cooling medium. 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 crank shaft 122. A low- temperature and low-pressure working fluid flows into the heater 118 from the regenerator 120 in accordance with the contraction of the compression chamber 116.

[0112] The regenerator 120 absorbs and stores the heat energy from the working fluid flowing from the heater 118, and transfers the stored heat energy to the working fluid flowing from the cooler 119. Accordingly, the working fluid in the expansion chamber 113 releases heat energy in the regenerator 120 before flowing into the cooler 119. The working fluid in the compression chamber 116 is heated by 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 the heat generating device 3 including the heat generating element 14 that generates heat by occluding and discharging hydrogen, and thus can supply energy inexpensively, cleanly, and safely.

[0114] (6) Heat Utilization System according to Sixth Embodiment FIG. 12 is a conceptual diagram schematically illustrating a configuration of a heat utilization system 1d according to a sixth embodiment. The heat utilization system 1d includes a heat utilization device 4c instead of the heat utilization device 4 according to the first embodiment. The heat utilization device 4c includes a thermoelectric converter 130 that generates electric power based on a temperature difference. The same or equivalent components and members as those of the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0115] The thermoelectric converter 130 includes heat receiving plates 131 and heat radiating plates 132. A high-temperature pipe 133 is in contact with the heat receiving plates 131. The high-temperature pipe 133 is connected to the piping path 2, and allows a heat medium to flow therethrough. A low-temperature pipe 134 is in contact with the heat radiating plate 132. The low-temperature pipe 134 allows cooling water to flow therethrough.

[0116] The thermoelectric converter 130 includes p-type semiconductors 135a and n-type semiconductors 135b that are sandwiched between the heat receiving plate 131 and the heat radiating plate 132 and arranged in parallel between the heat receiving plate 131 and the heat radiating plate 132. The p-type semiconductors 135a and the n-type semiconductors 135b are electrically alternately connected in series based on a first electrode fixed to the heat receiving plate 131 and a second electrode fixed to the heat radiating plate 132. The 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 the heat generating device 3 including the heat generating element 14 that generates heat by occluding and discharging hydrogen, and thus can supply energy inexpensively, cleanly, and safely.

[0118] The present invention is not limited to the above embodiments, and may be modified as appropriate without departing from the scope of the present invention.

[0119] The heat generating device 3 is not limited to a case of including one heat generating structure 8, and may include a plurality of heat generating structures 8.

[0120] In the heat utilization systems 1b,  1c, and 1d, the heat generating device 3 may include the heat generating structure 8a instead of the heat generating structure 8. Each of the heat utilization systems 1b, 1c, and 1d may include the heat generating device 3a instead of the heat generating device 3. Reference Sign List

[0121] 3, 3a heat generating device 5     sealed container 6     hydrogen tank 7     vacuum pump 8, 8a, 8b    heat generating structure 9      space 10    introduction pipe 11    exhaust pipe 12    supply valve 13    exhaust valve 14, 14a      heat generating element 15    heater 15a   outer peripheral surface 17    temperature sensor 18    conductive wire power supply control unit inner edge outer edge heat generating surface spacer support multilayer film first layer second layer heterogeneous material interface end member first frame first protrusion inner frame outer frame coupling unit second protrusion first surface second surface central axis

Claims

1. A heat generating structure comprising:a heat generating element 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; anda heater formed into a cylindrical shape and having an outer peripheral surface surrounded by the heat generating element, whereinthe multilayer film includes a first layer that is made of a hydrogen storage metal or a hydrogen storage alloy and has a thickness of less than 1,000 nm, and a second layer that is made of a hydrogen storage metal or a hydrogen storage alloy, which is different from that of the first layer, or ceramics and has a thickness of less than 1,000 nm, andthe heat generating element includes an inner edge disposed to face the outer peripheral surface, an outer edge disposed farther away from the outer peripheral surface than the inner edge in a second direction orthogonal to a first direction along a central axis of the heater, and a heat generating surface connecting the inner edge and the outer edge and extending continuously in a circumferential direction around the central axis, and transfers heat from the inner edge to the outer edge by heat conduction.

2. The heat generating structure according to claim 1, whereinthe inner edge and theouter edge extend continuously in thecircumferential direction, andthe heat generating surface is disposed in a plane orthogonal tothe first direction.

3. The heat generating structure according to claim 2, whereina plurality of heat generating elements including the heat generating element are disposed 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 disposed in the first direction.

5. The heat generating structure according to claim 4, further comprising:a pair of end members provided adjacent to the heat generating element disposed at an end in the first direction among the plurality of heat generating elements disposed in the first direction, whereinthe spacer includes a first frame disposed away from the outer peripheral surface in the second direction and a first protrusion protruding from the first frame in the first direction and abutting on the outer edge of the heat generating element, andeach of the pair of end members includes an inner frame abuttingon the outer peripheral surface, an outer frame disposed farther away from the outer peripheral surface than the inner frame in the second direction, a coupling unit coupling the inner frame and the outer frame, and a second protrusion protruding from the outer frame in the first direction and abutting on the outer edge of the heat generating element.

6. The heat generating structure according to claim 5, whereinthe first protrusion includes a plurality of first pins arranged at intervals in the circumferential direction, andthe second protrusion includes a plurality of second pins arranged at intervals in the circumferential direction.

7. The heat generating structure according to claim 1, whereina plurality of inner edges including the inner edge and a plurality of outer edges including the outer edge are disposed intermittently in the circumferential direction, andthe heat generating surface extends continuously while being alternately folded a plurality of times in the circumferential direction.

8. The heat generating structure according to claim 7, further comprising:a holding unit holding a shape of the heat generating element, whereinthe holding unit has a groove into which an end of the heatgenerating element in the first direction is fitted,the groove extends continuously while being alternately folded aplurality of times in the circumferential direction.

9. A heat generating device comprising:the heat generating structure according to any one of claims 1to 8;a sealed container accommodating the heat generating structuretherein;a supply unit configured to supply a hydrogen-based gas containing the hydrogen into the sealed container; anda discharge unit configured to discharge the hydrogen-based gas inside the sealed container.

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