JP5637452B2 - Induction heating apparatus and power generation system including the same - Google Patents

Description

  The present invention relates to an induction heating apparatus that heats a heat medium using induction heating, and a power generation system including the induction heating apparatus.

  As a device for heating water, a heating device using induction heating (eddy current) has been proposed (for example, see Patent Document 1). The eddy current heating device described in Patent Document 1 is a conductive rotor having a rotatable rotor having a permanent magnet arranged on the outer periphery and a fixed passage provided outside the rotor, and a flow passage through which water flows. A heating part for the material. Then, as the rotor rotates, the magnetic lines of force (magnetic flux) generated by the permanent magnets on the outer periphery of the rotor move through the heating unit, so that an eddy current is generated in the heating unit and the heating unit itself generates heat. As a result, the heat generated in the heating unit is transmitted to the water flowing through the internal flow passage, and the water is heated.

  The above-mentioned technology is mainly intended to supply hot water using energy such as wind power, but in recent years, power generation systems using renewable energy such as wind power, hydraulic power, and wave power are also attracting attention. .

  For example, Non-Patent Documents 1 to 3 describe technologies relating to wind power generation. In wind power generation, a windmill is rotated by wind and a generator is driven to generate electric power. Wind energy is converted into rotational energy and extracted as electric energy. A wind power generation system generally has a structure in which a nacelle is installed at the top of a tower, and a horizontal axis wind turbine (a wind turbine whose rotation axis is substantially parallel to the wind direction) is attached to the nacelle. The nacelle stores a speed increaser that speeds up and outputs the rotational speed of the rotating shaft of the windmill, and a generator that is driven by the output of the speed increaser. The speed increaser increases the number of rotations of the wind turbine to the number of rotations of the generator (for example, 1: 100), and a gear box is incorporated.

  Recently, there is a tendency to increase the size of a windmill (wind power generation system) in order to reduce the power generation cost, and a wind power generation system with a wind turbine diameter of 120 m or more and an output per unit of 5 MW has been put into practical use. Such large-scale wind power generation systems are huge and heavy, and are often constructed offshore for construction reasons.

  In wind power generation, the power generation output (power generation amount) fluctuates with the fluctuation of wind power. Therefore, a power storage system is added to the wind power generation system, unstable power is stored in the storage battery, and the output is smoothed. It has been broken.

JP 2005-174801 A

“Wind Power Generation (01-05-01-05)”, [online], Atomic Encyclopedia ATOMICA, [Search February 2, 2011], Internet <URL: http://www.rist.or.jp/ atomica /> “Subaru wind power generation system SUBARU WIND TURBINE”, [online], Fuji Heavy Industries, Ltd., [searched February 2, 2011], Internet <URL: http://www.subaru-windturbine.jp/windturbine/> “Wind Lecture”, [online], Mitsubishi Heavy Industries, Ltd. [Search February 2, 2011], Internet <URL: http://www.mhi.co.jp/products/expand/wind_kouza.html>

  However, the conventional eddy current heating apparatus as described in Patent Document 1 is configured to generate heat by using the eddy current generated when magnetic flux passes through the heating unit. Therefore, sufficient thermal energy (a calorific value) cannot be obtained, and there is a possibility that a heat medium (for example, a liquid such as water) cannot be heated to a desired temperature.

  On the other hand, in a generally well-known wind power generation system, a power storage system is installed for output smoothing, but the power storage system requires components such as a converter in order to store power in a storage battery. As a result, the system becomes complicated and power loss increases. Further, in the case of a large-scale wind power generation system, a large-capacity storage battery corresponding to the amount of power generation is required, which increases the cost of the entire system.

  Moreover, many of the causes of failure of the wind power generation system are due to problems with the gearbox, more specifically, the gear box. When a gearbox breaks down, it is usually dealt with by exchanging the gearbox. However, if a nacelle is installed at the top of the tower, it takes a lot of time and labor to install and remove the gearbox. So recently there are gearless variable-speed wind generators that do not require a gearbox.

  However, the gearless case can be dealt with by specifically increasing the number of poles of the generator (multipolar generator), but the generator becomes larger and heavier than when using a speed increaser. In particular, in a large-scale wind power generation system of 5 MW class, the weight of the generator is considered to exceed 300 tons (300000 kg), and it is difficult to arrange in the nacelle.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide an induction heating apparatus that can improve the amount of heat generation and has performance suitable for heating a heat medium. . Another object is to provide a power generation system including the induction heating device.

  The induction heating device of the present invention is a device that heats a heat medium, and includes a rotating body having a rotating shaft, and a protrusion made of a magnetic material that is arranged at a distance from the rotating body and protrudes toward the rotating body. A stator portion, and a coiled pipe made of a conductive metal that is disposed on the outer periphery of the protrusion and serves as a flow path for the heat medium. The rotating body is provided with a magnetic flux generator that generates a magnetic flux that passes through the protrusion in the protruding direction. In addition, the ends of the pipes are electrically connected by a connection conductor.

  First, the mechanism by which the heat medium in the induction heating apparatus of the present invention is heated will be described. In this induction heating device, a magnetic flux that passes through the protrusion is generated from the magnetic flux generator, and the magnetic flux generator rotates together with the rotating body, so that the distance between the magnetic flux generator and the protrusion of the stator is narrow → wide. Alternatively, the magnetic flux passing through the protrusion changes periodically from wide to narrow. As a result, an induced electromotive force (counterelectromotive force) is generated in the coiled pipe arranged on the outer periphery of the protruding portion, and the ends of the pipes are electrically connected by the connecting conductors. Since the induced current flows, the pipe generates heat, and the heat medium in the pipe is heated. Moreover, since the magnetic flux generation part rotates together with the rotating body, the magnetic flux passing through the pipe also changes. Therefore, the eddy current flows through the pipe, the pipe generates heat, and the heat medium in the pipe is heated. The induction heating apparatus of the present invention uses not only eddy currents but also currents (inductive currents) mainly caused by induced electromotive force, so that the pipe (heat medium) is effectively heated, and conventional eddy current heating is performed. It is considered that the calorific value is improved as compared with the apparatus.

  Examples of the magnetic material forming the protrusion include materials that can easily pass magnetic flux, such as iron, nickel, cobalt, silicon steel, permalloy, and ferrite. On the other hand, examples of the conductive metal forming the pipe include metals such as copper, aluminum, iron, and titanium, alloys thereof, and alloys such as stainless steel. Further, the connection conductor is a member that electrically connects the ends of the pipe in order to cause an induced current to flow through the pipe. For example, the connection conductor may be formed of the above-described conductive metal, particularly a good conductor having high conductivity. . Specifically, it is preferably formed of copper, aluminum, or an alloy thereof. Examples of the heat medium include water, oil, liquid metals (Na, Pb, etc.), liquids such as molten salts, and gases.

  In addition, by attaching the pipe to the protrusion of the stator part that is fixed without rotating, the pipe can be rotated to connect the pipe to the supply / discharge pipe that communicates with the pipe and supplies and discharges the heat medium from the outside. It is not necessary to use a rotating joint, and a robust connection can be realized with a simple configuration. Specifically, when the heat medium is heated, the pressure in the pipe increases. For example, when the heat medium is water (steam), it is considered that the pressure reaches about 25 MPa (250 atm) at 600 ° C. When the pipe rotates, a special rotary joint that can withstand the pressure is required. When the pipe is fixed without rotating, there is no need for a rotary joint. For example, welding is used to connect the supply / discharge pipe and the pipe. Even if such a simple method is adopted, a sufficiently robust connection structure can be realized.

  As one form of the induction heating apparatus of this invention, it is mentioned that the resistance value of the whole piping is high with respect to the resistance value of a connection conductor.

  As described above, it is preferable that the connection conductor is formed of a material having high conductivity and has a low resistance value. On the other hand, the pipe is preferably formed of a material that easily generates heat when an induced current flows, that is, is easily heated by induction, and preferably has a certain resistance value. According to the above configuration, since the resistance value of the entire pipe is higher than the resistance value of the connection conductor, heat is easily generated in the pipe and heat generation is difficult in the connection conductor, so it is suitable for heating the pipe (heat medium). It becomes the composition. Both the pipe and the connection conductor are members through which current flows, but the amount of heat generation can be improved by making the resistance values of the pipe and the connection conductor different in this way. For example, as a combination of materials used for the pipe and the connection conductor, the pipe uses at least one selected from the group consisting of iron, titanium, an alloy thereof, and stainless steel, and the connection conductor includes copper, aluminum, and its It is preferable to use at least one selected from the group consisting of alloys. In addition, the resistance value of the whole piping means the resistance value including the conductor resistance of all the piping structural members, when piping is comprised with several material (member).

  One form of the induction heating device of the present invention is a multilayer tube having an inner layer in which piping serves as a flow path for the heat medium and an outer layer disposed on the outer periphery of the inner layer, and the conductivity of the inner layer becomes the conductivity of the outer layer. In contrast, it is expensive.

  The induced current easily flows to the outside (surface) of the pipe due to the skin effect. According to the above configuration, since the conductivity of the inner layer is higher than the conductivity of the outer layer, a larger amount of current can flow through the inner layer, and the inner layer in contact with the heat medium can be effectively heated. Therefore, the heat medium can be efficiently heated. For example, the inner layer uses at least one selected from the group consisting of copper, aluminum and alloys thereof, and the outer layer uses at least one selected from the group consisting of iron, titanium and alloys thereof and stainless steel. Is mentioned. When copper, aluminum, or an alloy thereof is used for the inner layer, these materials are also excellent in thermal conductivity, so that heat conduction from the inner layer to the heat medium can be performed efficiently. In addition, when iron, titanium, its alloys, or stainless steel is used for the outer layer, these materials are also excellent in mechanical strength. Therefore, the outer layer functions as a reinforcing material that increases the strength of the piping, and increases the durability and pressure resistance of the piping. be able to.

  As one form of the induction heating device of the present invention, the pipe has a pipe part serving as a flow path of the heat medium and at least one convex part protruding inward from the inner peripheral surface of the pipe part and extending in the longitudinal direction, It is mentioned that the conductivity of the convex portion is higher than the conductivity of the tube portion.

  As described above, the induced current easily flows to the outside (surface) of the pipe due to the skin effect. According to the above configuration, since the conductivity of the convex portion is higher than the conductivity of the tube portion, more current can flow through the convex portion, and the convex portion in contact with the heat medium can effectively generate heat. Can do. Therefore, the heat medium can be efficiently heated. For example, the convex part uses at least one selected from the group consisting of copper, aluminum and alloys thereof, and the pipe part uses at least one selected from the group consisting of iron, titanium and alloys thereof and stainless steel To do. When such a material is used for the convex part, heat conduction from the convex part to the heat medium can be efficiently performed. On the other hand, when such a material is used for the pipe part, the durability and pressure resistance of the pipe part are improved. Can increase the sex. Further, by providing a plurality of convex portions on the inner peripheral surface of the tube portion, the contact area between the convex portions and the heat medium can be increased, and the heat medium can be heated more efficiently.

  As one form of the induction heating device of the present invention, a pipe has a pipe part serving as a flow path for a heat medium and an inner conductor disposed in the pipe part and extending in the longitudinal direction, and the conductivity of the inner conductor is the conductivity of the pipe part. It is mentioned that it is high for the rate.

  As described above, the induced current easily flows to the outside (surface) of the pipe due to the skin effect. According to the above configuration, since the conductivity of the inner conductor is higher than the conductivity of the tube portion, more current can flow through the inner conductor, and the inner conductor in contact with the heat medium can be effectively heated. Can do. Therefore, the heat medium can be efficiently heated. For example, the inner conductor uses at least one selected from the group consisting of copper, aluminum and alloys thereof, and the pipe uses at least one selected from the group consisting of iron, titanium and alloys thereof and stainless steel. To do. When such a material is used for the inner conductor, heat conduction from the inner conductor to the heat medium can be efficiently performed. On the other hand, when such a material is used for the pipe, the durability and pressure resistance of the pipe Can increase the sex. In addition, the form of an internal conductor is not specifically limited, For example, it can be set as arbitrary forms, such as a wire, a bar, a board | plate material, and a pipe material. In addition, the cross-section (cross-section in the direction perpendicular to the longitudinal direction) of the inner conductor is not particularly limited, and may be any shape such as a circle, an ellipse, a polygon such as a triangle or a quadrangle, a cross or a star can do. When the cross-sectional outer shape of the inner conductor has a longer outer circumference than a circle, the contact area between the inner conductor and the heat medium increases, and the heat medium can be heated more efficiently.

  As one form of the induction heating apparatus of this invention, it is mentioned that the magnetic flux which generate | occur | produces from a magnetic flux generation part is a thing by a coil.

  A permanent magnet or a coil (electromagnet) can be used as the magnetic flux generating means. Examples of the coil include a normal conducting coil such as a copper wire and a superconducting coil using a superconducting wire. When using a coil, compared with the case where a permanent magnet is used, a strong magnetic field can be generated. Specifically, it is possible to generate a strong magnetic field by increasing the current supplied to the coil, and it is also possible to adjust the strength of the magnetic field by controlling the supplied current. Since the calorific value is proportional to the square of the magnetic field intensity, further improvement in the calorific value can be expected. In addition, in the case of a coil, compared to a permanent magnet, the magnetic characteristics are less likely to deteriorate due to a temperature rise, and the magnetic characteristics are less likely to deteriorate over time. Therefore, when the magnetic flux generated from the magnetic flux generator is generated by a coil, it is easy to maintain a sufficient magnetic field intensity by increasing the energization current, and heat the heat medium to a predetermined temperature (for example, 100 ° C. to 600 ° C.). Sufficient performance (thermal energy) can be obtained. For example, in the eddy current heating device disclosed in Patent Document 1 described above, the permanent magnet is disposed at a position close to the heating unit and close to the heating unit. Therefore, the temperature of the permanent magnet increases due to the influence of heat from the heating unit. It is easy and it is thought that there exists a possibility that a magnetic characteristic may fall and a heat medium may not be heated to desired temperature as a result. Note that a direct current is passed through the coil to generate a direct magnetic field.

  Furthermore, when a direct current is passed through the coil to generate a direct current magnetic field, if it is a superconducting coil, the electrical resistance is zero, and even if a large current is passed, heat generation (loss) does not substantially occur in the coil. Therefore, compared to a normal conducting coil, heat generation (loss) of the coil caused by flowing a large current can be suppressed, and an extremely strong magnetic field can be maintained without power loss.

  As one form of the induction heating apparatus of this invention, a rotating shaft is connected to a windmill and using wind power for the motive power which rotates a rotary body is mentioned.

An internal combustion engine such as an electric motor or an engine can be used for the power of the rotating body (rotating shaft), but it is preferable to use renewable energy such as wind power, hydraulic power, and wave power. If renewable energy is used, an increase in CO ₂ can be suppressed, and it is particularly preferable to use wind power.

  The power generation system of the present invention includes the above-described induction heating device of the present invention, and a power generation unit that converts heat of the heat medium heated by the induction heating device into electrical energy.

  This power generation system uses the heat of the heat medium heated by using the above-described induction heating device for power generation, and is a new power generation system that has not existed before. For example, if a windmill is connected to the rotating shaft of the induction heating device and wind power is used as the power of the rotating body, the wind energy can be converted from rotational energy to thermal energy and extracted as electrical energy. And according to this electric power generation system, it was set as the structure which converts heat into electrical energy, By storing energy as heat using a thermal accumulator, efficient and stable electric power generation is realizable. In addition, a heat storage system that can store heat in the heat accumulator and simultaneously extract heat necessary for power generation from the heat accumulator is simpler than the power storage system, and the heat accumulator is less expensive than the storage battery. Furthermore, it is not necessary to provide a speed increaser as in the conventional wind power generation system, and it is possible to avoid a gearbox trouble.

  In the induction heating device of the present invention, a coiled pipe serving as a flow path for a heat medium is disposed on a protrusion of a stator part, an induced current is induced in the pipe, and the pipe is heated by the induced current to generate heat in the pipe. By heating the medium, the amount of heat generated can be improved. Further, the power generation system of the present invention can generate power by converting the heat of the heat medium heated using the above-described induction heating device into electric energy by the power generation unit.

It is the schematic of the induction heating apparatus which concerns on Embodiment 1, (A) is an exploded perspective view, (B) is an assembly perspective view. It is the schematic of the induction heating apparatus which concerns on Embodiment 1, and is front sectional drawing cut | disconnected in the direction orthogonal to the axial direction of a rotary body. 3 is a partial schematic diagram showing a piping portion in the induction heating apparatus according to Embodiment 1. FIG. It is a schematic sectional drawing which shows the modification of piping in an induction heating apparatus, (A) shows an example in which piping is a 2 layer pipe | tube which has an inner layer and an outer layer, (B) shows piping inside a pipe part and a pipe part. An example which has a convex part which protrudes inward from a surrounding surface is shown, and (C) shows an example in which piping has a pipe part and an internal conductor arranged in the pipe part. It is the partial schematic which shows the modification of the connection structure of piping and a connection conductor in an induction heating apparatus. It is a schematic perspective view which shows the modification of the projection part in an induction heating apparatus. It is the schematic which shows an example of the whole structure of the electric power generation system which concerns on this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

<Induction heating device>
(Embodiment 1)
The induction heating apparatus 101 according to the first embodiment shown in FIGS. 1 to 3 includes a rotating body 11, a stator section 12 having a protrusion 121 protruding in the direction of the rotating body 11, and a coil shape serving as a heat medium flow path. The piping 14 is provided. Hereinafter, the configuration of the induction heating apparatus 101 will be described in detail.

  The rotating body 11 has a rotating shaft 21 that is rotatably supported, and an outer shape viewed from the axial direction is formed in a gear shape having a plurality of convex portions 111 protruding in the radial direction. In this example, eight convex portions 111 are provided, and each convex portion 111 is formed at equal intervals in the circumferential direction. Further, on the outer periphery of the rotator 11, a magnetic flux generator (coil 15 in this example) described later is provided. Here, it is assumed that the rotating body 11 rotates counterclockwise (the arrow in FIG. 2 indicates the direction of rotation).

  The material for forming the rotating body 11 may be any material that has mechanical strength and can support the coil 15 regardless of whether it is a magnetic material or a non-magnetic material, and has structural strength and long-term durability (weather resistance and corrosion resistance). ) Is preferred. Examples thereof include composite materials such as iron, steel, stainless steel, aluminum alloy, magnesium alloy, GFRP (glass fiber reinforced plastic) and CFRP (carbon fiber reinforced plastic) used for structural materials.

  In this example, the rotating body 11 (including the convex portion 111) is formed of a nonmagnetic material. When a normal conducting coil is used for the coil 15, the rotating body 11 is preferably formed of a magnetic material. On the other hand, when a superconducting coil is used, there is a possibility that the generated magnetic field may be limited due to magnetic flux saturation of the rotator 11, and therefore it may be preferable to form the rotator 11 with a nonmagnetic material.

  The stator portion 12 is arranged on the outer side in the radial direction of the rotating body 11 with a space from the rotating body 11, and is fixed so as not to rotate. This stator portion 12 protrudes in a centripetal direction (inward in the radial direction) from a yoke portion 125 made of a magnetic material formed in a cylindrical shape so as to surround the periphery of the rotating body 11, and from the inner peripheral surface of the yoke portion 125. And a protrusion 121 made of a magnetic material. In this example, the stator portion 12 has a plurality of (eight) protrusion portions 121, each protrusion portion 121 is provided at equal intervals in the circumferential direction, and each protrusion portion 121 is connected to a yoke portion 125 to be connected to the yoke portion. They are connected via 125 (see FIG. 2). That is, the number of convex portions 111 of the rotator 11 is equal to the number of protrusions 121 of the stator portion 12. Each projection 121 is a quadrangular prism that is parallel to the axial direction of the stator 12 and has a substantially rectangular cross section in a direction orthogonal to the protruding direction.

  The coil 15 is fitted and attached to the outside of each convex portion 111 of the rotating body 11, and generates a magnetic flux in the radial direction of the rotating body 11, and generates a magnetic flux that passes through the protrusion 121 in the protruding direction. Part. A DC power source (not shown) is connected to each coil 15. In this example, the direction of a direct current flowing through each coil 15 is controlled to determine the direction of the magnetic field (magnetic flux) to be generated, so that the polarities of adjacent coils 15 are different from each other (see FIG. 2). ). Each coil 15 is a superconducting coil, and is covered with a cooling jacket (not shown) and kept in a superconducting state by cooling. As the coil 15, a normal conducting coil may be used, and a permanent magnet may be used instead of the coil 15. Further, the coil 15 may be connected to an external power source via, for example, a slip ring and supplied with current.

  The pipe 14 is a coil-shaped member made of a conductive metal, is fitted and attached to the outside of each projection 121, and is disposed on the outer periphery of each projection 121. Further, the ends (the winding start portion and the winding end portion) of the pipe 14 are electrically connected by a connecting conductor 141 (see FIG. 3). In this example, the pipe 14 is formed of a single conductive metal, and the pipe 14 includes a conductive metal having a high resistivity (low conductivity), specifically, iron, titanium or an alloy thereof, or Stainless steel is used, and the connection conductor 141 is a good conductor with high conductivity, specifically, copper, aluminum, or an alloy thereof. The resistance value from the start of winding of the pipe 14 to the end of winding is designed to be higher than the resistance value of the connecting conductor 141. The piping 14 is supplied with a heat medium from one end, and is discharged from the other end, so that the heat medium flows.

  Further, a heat insulating material (not shown) may be arranged on the outer periphery of the pipe 14. As the heat insulating material, for example, rock wool, glass wool, foamed plastic, brick, ceramics, or the like can be used.

  Next, the mechanism by which the heat medium in the induction heating device 101 is heated will be described in detail.

  In the induction heating device 101, when the coil 15 is energized, a magnetic flux is generated in the radial direction of the rotating body 11, and the coil 15 rotates together with the rotating body 11, whereby the distance between the coil 15 and the protrusion 121. Becomes narrow → wide or wide → narrow, and the magnetic flux passing through the protrusion 121 changes periodically. As a result, an induced electromotive force (counterelectromotive force) is generated in the coiled pipe 14 arranged on the outer periphery of the protruding portion 121, and the induced current flows through the pipe 14 to cause the pipe 14 to generate heat. The heat medium is heated. Further, when the coil 15 rotates together with the rotating body 11, the magnetic flux passing through the pipe 14 also changes, so that an eddy current flows through the pipe 14 and the pipe 14 generates heat and the heat medium in the pipe 14 is heated. The Therefore, in this induction heating device 101, unlike the conventional eddy current heating device, an induction current is induced in the coiled piping 14, and the heating medium in the piping 14 is heated mainly by generating heat by the induction current. To do.

  Here, in the induction heating device 101, since the resistance value of the pipe 14 is higher than the resistance value of the connection conductor 141, the pipe 14 easily generates heat and the connection conductor 141 hardly generates heat. ) Is suitable for heating, and the calorific value can be improved. Further, since each projection 121 is connected via a yoke portion 125 made of the same magnetic material, the magnetic flux flowing through each projection 121 can be increased, and further improvement in the amount of heat generation can be expected.

  In addition, in the induction heating device 101, since the polarities of the adjacent coils 15 are different from each other, a magnetic flux (magnetic field) is generated when the protrusion 121 faces the N-pole coil 15 and when it faces the S-pole coil 15. The direction of is different. When facing the N-pole coil 15, the direction of the magnetic flux passing through the protrusion 121 is the direction from the rotating body 11 to the yoke 125 (the radial + direction). On the other hand, when facing the S-pole coil 15, the direction of the magnetic flux passing through the protrusion 121 is the direction from the yoke 125 to the rotating body 11 (the radial negative direction). That is, as the coil 15 rotates together with the rotating body 11, the direction of the magnetic flux (magnetic field) changes while periodically reversing.

(Modification 1)
In the induction heating apparatus 101 according to the first embodiment described above, the case where the pipe 14 is made of a single material (member) has been described as an example. However, as described below with reference to FIG. 14 may be composed of a plurality of materials (members). 4A to 4C all show a cross section in a direction orthogonal to the longitudinal direction of the pipe.

  A pipe 14A illustrated in FIG. 4A is a two-layer pipe having an inner layer 14a serving as a heat medium flow path and an outer layer 14b disposed on the outer periphery of the inner layer 14a. For example, copper, aluminum, or an alloy thereof is used for the inner layer 14a, and iron, titanium, an alloy thereof, or stainless steel is used for the outer layer 14b. The conductivity of the inner layer 14a is higher than the conductivity of the outer layer 14b. Designed to be high. This pipe 14A is formed, for example, by processing a clad material obtained by pressure-bonding a material plate forming the inner layer 14a and a material plate forming the outer layer 14b into a tubular shape, or forming the inner layer 14a on a material plate forming the outer layer 14b. It can be obtained by processing the plating material plated with the material to be processed into a tubular shape. Alternatively, it can be obtained by concentrically arranging the inner tube made of the material forming the inner layer 14a and the outer tube made of the material forming the outer layer 14b.

  In this pipe 14A, since the conductivity of the inner layer 14a is higher than the conductivity of the outer layer 14b, a large amount of induced current that tends to concentrate on the outside (surface) can flow through the inner layer 14a, and the inner layer 14a in contact with the heat medium Can effectively generate heat. Therefore, the heat medium can be effectively heated. Here, when the cross-sectional area of the inner layer 14a is increased, the resistance value decreases and it is difficult to generate heat. Therefore, the cross-sectional area of the inner layer 14a (the thickness of the inner layer 14a) is set so that an appropriate resistance value is easily generated. Is preferred. Furthermore, when copper, aluminum, or an alloy thereof is used for the inner layer 14a, the heat conductivity is excellent, and therefore heat conduction from the inner layer 14a to the heat medium can be performed efficiently. On the other hand, when iron, titanium, an alloy thereof, or stainless steel is used for the outer layer 14b, it has excellent mechanical strength, so that it functions as a reinforcing material that increases the strength of the piping 14A, and can improve the durability and pressure resistance of the piping 14A. .

  The pipe 14B illustrated in FIG. 4B has a pipe part 14c that serves as a flow path for the heat medium and a convex part 14d that protrudes inward from the inner peripheral surface of the pipe part 14c. In this example, the two-layer tube having the inner layer 14a and the outer layer 14b illustrated in FIG. 4A is used as the tube portion 14c, and the description of the configuration of the tube portion 14c is omitted. The convex portion 14d uses the same type of conductive metal as the inner layer 14a of the tube portion 14c, and is formed integrally with the inner layer 14a. A plurality of convex portions 14d are provided on the inner peripheral surface of the tube portion 14c (inner layer 14a), and extend in a series in the longitudinal direction. This pipe 14B is formed, for example, by forming a convex portion 14d integrally with a material plate forming the inner layer 14a by extrusion or the like, and processing a clad material obtained by pressure bonding the plate and a material plate forming the outer layer 14b into a tubular shape. Alternatively, the convex portion 14d is formed integrally with the inner tube of the material forming the inner layer 14a, and the inner tube and the outer tube of the material forming the outer layer 14b are arranged concentrically. it can.

  In this pipe 14B, since the conductivity of the convex portion 14d is higher than the conductivity of the pipe portion 14c (outer layer 14b), a large amount of induced current can flow through the convex portion 14d, and the convex portion 14d that contacts the heat medium. Can effectively generate heat. Therefore, the heat medium can be effectively heated. Further, since the plurality of convex portions 14d are provided on the inner peripheral surface of the tube portion 14c, the contact area between the convex portions 14d and the heat medium is increased, so that the heat medium can be heated more efficiently. Here, when the cross-sectional area of the convex portion 14d is increased, the resistance value decreases and it is difficult to generate heat. Therefore, the cross-sectional area of the convex portion 14d (the number and size of the convex portions 14d) is set so that an appropriate resistance value is easily generated. Is preferably set. Furthermore, when copper, aluminum, or an alloy thereof is used for the convex portion 14d, heat conduction from the convex portion 14a to the heat medium can be efficiently performed.

  A pipe 14C illustrated in FIG. 4C includes a pipe part 14c that serves as a flow path for the heat medium, and an internal conductor 14e disposed in the pipe part 14c. For example, copper, aluminum, or an alloy thereof is used for the inner conductor 14e, and iron, titanium, an alloy thereof, or stainless steel is used for the tube portion 14c. The conductivity of the inner conductor 14e is the conductivity of the tube portion 14c. Designed to be higher with respect to rate. Further, the inner conductor 14e extends in a series in the longitudinal direction, and in this example, the inner conductor 14e is a wire having a substantially rectangular cross section.

  In this pipe 14C, since the conductivity of the inner conductor 14e is higher than the conductivity of the pipe portion 14c, a large amount of induced current can flow through the inner conductor 14e, and the inner conductor 14e in contact with the heat medium is effectively prevented. Can generate heat. Therefore, the heat medium can be effectively heated. Here, if the cross-sectional area of the internal conductor 14e is increased, the resistance value decreases and it is difficult to generate heat. Therefore, the cross-sectional area of the internal conductor 14e (the number and size of the internal conductors 14e) is set so that an appropriate resistance value is easily generated. Is preferably set. Furthermore, when copper, aluminum, or an alloy thereof is used for the inner conductor 14e, heat conduction from the inner conductor 14e to the heat medium can be efficiently performed. In this example, the case where the inner conductor 14e is a wire having a rectangular cross section is taken as an example, but the present invention is not limited to this, and the form of the inner conductor 14e may be a bar or a plate. The cross-sectional shape of the inner conductor 14e may be a circle other than a circle or a rectangle. In addition, if the cross-sectional outer shape of the inner conductor 14e is selected so that the outer circumference of the inner conductor 14e cross section becomes longer, the contact area between the inner conductor 14e and the heat medium can be increased, and the heat medium can be made more efficient. Can be heated.

  In the configuration of the pipe described above, different conductive metals are used for the inside and the outside of the pipe. In the case of the pipes 14A and 14B illustrated in FIGS. 4A and 4B, the material forming the inner side (the inner layer 14a of the pipe 14A, the convex part 14d of the pipe 14B (the inner layer 14a of the pipe part 14c)) and the connecting conductor 141 (Refer to FIG. 3) is indirectly electrically connected via the material forming the outside of the pipe (the outer layer 14b of the pipe 14A and the outer layer 14b of the pipe portion 14c of the pipe 14B). In addition, in the piping 14C illustrated in FIG. 4C, for the sake of easy understanding, the inner conductor 14e is shown not contacting the pipe portion 14c in the drawing. 14e does not float over the entire length in the longitudinal direction, and there is a place where the inner conductor 14e and the inner peripheral surface of the tube portion 14c are in contact with each other. Therefore, also in the case of the pipe 14C, the material forming the inner side (the inner conductor 14e of the pipe 14C) and the connection conductor 141 (see FIG. 3) are indirectly electrically connected via the pipe portion 14c of the pipe 14C. Will be.

  Here, when the contact between the material forming the inner side of the pipe and the material forming the outer side is insufficient, partial discharge may occur when an induced current flows. Therefore, for example, in the case of the pipes 14A and 14B, an opening may be provided in the outer layer 14b, and the exposed inner layer 14a and the connection conductor 141 (see FIG. 3) may be directly electrically connected. On the other hand, in the case of the pipe 14C, for example, a through hole is provided in the peripheral wall of the pipe portion 14c, and the internal conductor 14e is drawn out in a sealed state from the through hole, and the internal conductor 14e and the connection conductor 141 (see FIG. 3) are connected. It may be directly electrically connected. In the case of the pipe 14C, for example, as shown in FIG. 5, an end joint 145 is connected to the open end of the pipe 14C (pipe part 14c), and the internal conductor 14e extended from the open end is connected to the end joint. The internal conductor 14e and the connection conductor 141 (see FIG. 3) may be directly and electrically connected by being drawn out from a through hole provided in the peripheral wall 145 in a sealed state.

(Modification 2)
In the induction heating apparatus 101 according to the first embodiment described above, the case where the cross section of the protrusion 121 of the stator portion 12 (the cross section in the direction orthogonal to the protruding direction) is a substantially rectangular quadrangular prism has been described as an example. It is not limited to. For example, as shown in FIG. 6, a skew structure in which the protrusion 121 is inclined with respect to the axial direction of the stator 12 can be cited. By adopting the skew structure, the cogging torque can be reduced and the rotation of the rotating body 11 can be made smooth. Further, the convex portion 111 of the rotating body 11 may have a skew structure.

<Power generation system>
Next, an example of the overall configuration of the power generation system according to the present invention will be described with reference to FIG. The power generation system P shown in FIG. 7 includes an induction heating device 10, a windmill 20, a heat accumulator 50, and a power generation unit 60. The wind turbine 20 is attached to a nacelle 92 installed at the upper part of the tower 91, and the induction heating device 10 is stored in the nacelle 92. Further, the heat accumulator 50 and the power generation unit 60 are installed in a building 93 built at the lower part (base) of the tower 91. Hereinafter, the configuration of the power generation system P will be described in detail.

  The induction heating device 10 is the induction heating device of the present invention, and for example, the induction heating device 101 according to the first embodiment described above can be used. Further, the other end side of the rotating shaft 21 is directly connected to a windmill 20 described later, and wind power is used as power for rotating the rotating body. Here, a case where the heat medium is water will be described as an example.

  The windmill 20 has a structure in which three blades 201 are radially attached to the rotary shaft 21 around a rotary shaft 21 extending in the horizontal direction. In the case of a wind power generation system with an output exceeding 5 MW, the diameter is 120 m or more and the rotation speed is about 10 to 20 rpm.

  Connected to the piping of the induction heating apparatus 10 are a water supply pipe 73 that supplies water to the induction heating apparatus 10 and a transport pipe 51 that sends the water heated by the induction heating apparatus 10 to the regenerator 50. Then, the induction heating device 10 generates an induction current in the coiled pipe arranged in the protrusion by changing the magnetic flux passing through the protrusion when the coil is energized and the coil rotates together with the rotating body. The water in the pipe is heated by causing the pipe to generate heat by an induced current. The induction heating device 10 induces an induction current in a coiled pipe through which the heat medium flows, and heats the heat medium in the pipe mainly by generating heat by the induction current. It is possible to heat the water which is, for example, to a high temperature such as 100 ° C. to 600 ° C. For example, the pipe temperature can be raised to around the temperature at which the pipe material melts by appropriately disposing a heat insulating material on the outer periphery of the pipe or appropriately setting the flow rate of the heat medium. In addition, since the induction heating device 10 has a structure in which the pipe does not rotate, it is not necessary to use a rotary joint for connecting the pipe to the transport pipe 51 and the water supply pipe 73, for example, using welding or the like, with a simple configuration, A robust connection can be realized.

  In the power generation system P, water is heated to a temperature suitable for power generation (for example, 200 ° C. to 550 ° C.) by the induction heating device 10 to generate high-temperature and high-pressure water. The high-temperature high-pressure water is sent to the regenerator 50 through a transport pipe 51 that connects the induction heating device 10 and the regenerator 50. The heat accumulator 50 stores the heat of the high-temperature and high-pressure water sent through the transport pipe 51, and supplies steam necessary for power generation to the power generation unit 60 using a heat exchanger. Note that steam may be generated by the induction heating device 10.

  As the heat accumulator 50, for example, a steam accumulator, a sensible heat type using a molten salt or oil, or a latent heat type heat accumulator using a phase change of a molten salt having a high melting point can be used. Since the latent heat type heat storage method stores heat at the phase change temperature of the heat storage material, the heat storage temperature range is generally narrower than that of the sensible heat type heat storage method, and the heat storage density is high.

  The power generation unit 60 has a structure in which a steam turbine 61 and a generator 62 are combined. The steam turbine 61 is rotated by the steam supplied from the heat accumulator 50, and the generator 62 is driven to generate power.

  The high-temperature high-pressure water or steam sent to the regenerator 50 is cooled by the condenser 71 and returned to the water. After that, it is sent to the pump 72 and is circulated by being made into high-pressure water and sent to the induction heating device 10 through the water supply pipe 73.

  According to this power generation system P, it is possible to generate rotational energy by using renewable energy (eg, wind power) as power, generate heat, and store the heat in a heat accumulator to generate electricity, so that an expensive storage battery is not used. However, stable power generation according to demand can be realized. Further, it is not necessary to provide a speed increaser unlike the conventional wind power generation system, and it is possible to avoid a gearbox trouble. Furthermore, by supplying the heat of the heat medium to the power generation unit installed in the lower part (base) of the tower, for example, by a transport pipe, there is no need to store the power generation part in the nacelle, and the nacelle installed in the upper part of the tower is made small -It can be reduced in weight.

  In the power generation system described above, the case where water is used as the heat medium has been described as an example. However, a liquid metal having a higher thermal conductivity than water may be used as the heat medium. An example of such a liquid metal is liquid metal sodium. When using a liquid metal as a heat medium, for example, a liquid metal is used as a primary heat medium that circulates in a pipe, and a secondary heat medium (via a heat exchanger with heat of the liquid metal sent through a transport pipe ( It is considered that water is heated to generate steam.

  In addition, when oil, liquid metal, molten salt, or the like having a boiling point of more than 100 ° C. at normal pressure is used as the heat medium, the heat medium in the pipe when heated to a predetermined temperature compared to water It is easy to suppress an increase in internal pressure due to vaporization.

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention. For example, the material, shape, configuration, etc. of the piping can be changed as appropriate.

  The induction heating apparatus of the present invention can be used for, for example, a hot water supply system and a heating system, in addition to being used for a power generation system using renewable energy. Moreover, the power generation system of the present invention can be suitably used in the field of power generation using renewable energy.

10,101 Induction heating device P Power generation system
11 Rotating body
111 Convex
12 Stator section
121 Projection 125 Yoke
14,14A, 14B, 14C Piping
141 Connection conductor
14a Inner layer 14b Outer layer 14c Pipe
14d Convex 14e Inner conductor
145 End fitting
15 Magnetic flux generator (coil)
21 Rotation axis
20 Windmill 201 Wings
50 Heat storage unit 51 Transport pipe
60 Power generation section 61 Steam turbine 62 Generator
71 Condenser 72 Pump 73 Water supply pipe
91 Tower 92 Nasser 93 Building

Claims (9)

An induction heating device for heating a heat medium,
A rotating body having a rotation axis;
A stator portion having a protrusion made of a magnetic material that is arranged at a distance from the rotor and protrudes in the direction of the rotor;
A coiled pipe made of a conductive metal disposed on the outer periphery of the protrusion and serving as a flow path for the heat medium; and
The rotating body is provided with a magnetic flux generator that generates a magnetic flux that passes through the protrusion in the protruding direction.
An induction heating device, wherein ends of the pipes are electrically connected by a connecting conductor.   The induction heating apparatus according to claim 1, wherein a resistance value of the entire pipe is higher than a resistance value of the connection conductor. For the piping, at least one selected from the group consisting of iron, titanium and alloys thereof and stainless steel is used,
The induction heating device according to claim 1 or 2, wherein at least one selected from the group consisting of copper, aluminum, and alloys thereof is used for the connection conductor. The pipe is a multilayer pipe having an inner layer that serves as a flow path for the heat medium and an outer layer disposed on the outer periphery of the inner layer,
The induction heating apparatus according to any one of claims 1 to 3, wherein the inner layer has a higher conductivity than the outer layer. The pipe has a pipe part serving as a flow path for the heat medium, and at least one convex part protruding inward from the inner peripheral surface of the pipe part and extending in the longitudinal direction;
The induction heating device according to any one of claims 1 to 4, wherein the conductivity of the convex portion is higher than the conductivity of the tube portion. The pipe has a pipe portion serving as a flow path of the heat medium, and an internal conductor disposed in the pipe portion and extending in a longitudinal direction;
The induction heating device according to any one of claims 1 to 5, wherein the conductivity of the inner conductor is higher than the conductivity of the pipe portion.   The induction heating apparatus according to any one of claims 1 to 6, wherein a magnetic flux generated from the magnetic flux generation unit is a coil. The rotating shaft is connected to a windmill;
The induction heating apparatus according to any one of claims 1 to 7, wherein wind power is used as power for rotating the rotating body. The induction heating device according to any one of claims 1 to 8,
A power generation system comprising: a power generation unit that converts heat of the heat medium heated by the induction heating device into electrical energy.

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