JP5504935B2 - Heat medium heating device and power generation system including the same - Google Patents

Description

  The present invention relates to a heat medium heating device that heats a heat medium using reciprocating motion of a fluid existing in nature and a power generation system including the heat medium heating device.

In recent years, from the viewpoint of CO ₂ reduction, power generation systems using natural energy (renewable energy) such as sunlight, solar heat, wind power, geothermal heat, and wave power have attracted attention. As one of the power generation methods using the reciprocating motion of fluid existing in nature, for example, wave power generation using wave vertical vibrations can be mentioned. Wave power is expected to be a promising energy resource because it has high energy density among natural energies and is less susceptible to fluctuations, and research and development of wave power generation is underway.

  For example, Non-Patent Document 1 describes a technology related to a wave power generation system including a direct link type wave power generation device (see FIG. 4). A wave power generation device 100 shown in FIG. 4 includes a float 110 that reciprocates in accordance with the vertical vibrations of the waves, a rod-like body 120 erected on the float 110, and a generator 130. The rod-shaped body 120 and the generator 130 are connected via a link mechanism (transmission mechanism) that changes a reciprocating motion (not shown) into a rotational motion. As the link mechanism, for example, a rack and pinion mechanism as described in Patent Document 1 (in particular, refer to FIG. 1 of Patent Document 1) can be cited.

  The wave power generation device 100 converts the reciprocating motion of the float 110 (rod-like body 120) due to the vertical vibration of the waves into a rotational motion via a link mechanism, and drives the generator 130 to generate power. That is, the reciprocating kinetic energy by the wave is converted into rotational kinetic energy and extracted as electric energy. Such a wave power generator has a relatively simple structure and can be easily reduced in size.

  Moreover, when constructing a wave power generation system using the above-described wave power generation device, since it is linked to a commercial power system, for example, a speed increaser (gear box) is used and the rotation speed corresponding to the commercial frequency is used. Then, the generator is rotated, or the alternating current generated by the generator is rectified and converted into direct current, and the direct current is converted into alternating current of commercial frequency by an inverter.

JP 2007-297929 A

Yu Komatsubara and two others, “Effect of design of float in direct link wave power generation system on conversion efficiency”, 2009 Electrical Engineering Society Kansai Branch Joint Conference G5-24

  However, in the conventional wave power generation device as shown in FIG. 4 described above, a link mechanism is necessary, so that durability is difficult and there is a problem in maintainability.

  Since the link mechanism is configured by combining parts such as gears, the link mechanism is prone to failure, and parts such as gears are susceptible to corrosion under the influence of tides.

  The present invention has been made in view of the above circumstances, and one of its purposes is heat that heats a heat medium by utilizing a reciprocating motion of a fluid existing in nature with a simple structure and excellent maintainability. The object is to provide a medium heating device and a power generation system including the same.

  The heat medium heating device of the present invention includes a float that reciprocates in accordance with a reciprocating motion of a fluid existing in nature, an energy conversion device that converts the reciprocating energy of the float into thermal energy, and heat that receives heat from the energy conversion device. And a medium.

  The power generation system of the present invention includes the heat medium heating device of the present invention and a power generation unit that converts heat of the heat medium into electric energy.

  The heat medium heating device of the present invention utilizes the reciprocating motion of a fluid existing in nature, converts the reciprocating kinetic energy into heat energy, and heats the heat medium without converting it into rotational kinetic energy. Therefore, there is no need for a complicated link mechanism that changes reciprocating motion into rotational motion, and excellent maintainability can be realized with a simple structure.

  On the other hand, the power generation system of the present invention uses the heat of the heat medium heated by using the above-described heat medium heating apparatus of the present invention for power generation, and is a novel power generation system that has not been heretofore known. For example, if the vertical vibration of the wave is used, the wave energy can be converted into heat energy and taken out as electric energy. According to the power generation system of the present invention, the reciprocating kinetic energy is converted into thermal energy, and the thermal energy is converted into electrical energy. For example, power generation is performed at an arbitrary frequency without using a speed increaser. It is possible to achieve an efficient power generation system with few failures.

  Further, the heat of the heated heat medium may be temporarily stored in the heat accumulator. When the generated electrical energy is stored in the storage battery, components such as an inverter that converts the power into an alternating current are necessary for grid connection, resulting in a complicated system and increased power loss. Furthermore, the heat accumulator is also advantageous in that it is less expensive than the storage battery.

  In the present invention, examples of the heat medium include water, oil, liquid metals (Na, Pb, etc.), liquids such as molten salts, and gases.

  In the heat medium heating device of the present invention, examples of the energy conversion device that converts reciprocating kinetic energy into heat energy include using induction heating or compression heat.

  In the case of using induction heating, as one form of the heat medium heating device of the present invention, the energy conversion device includes a magnetic field generating means and at least a part formed of a conductive material, and a magnetic flux by the magnetic field generating means passes. A heating unit. Then, either one of the magnetic field generating means and the heating unit is attached to the float, and the magnetic field generating means and the heating unit reciprocate relatively by the reciprocating motion of the float. Further, it may be provided with a pipe through which a heat medium flows and receives heat from a heating unit.

  According to this configuration, the magnetic field generating means and the heating unit reciprocate relatively, so that an induction current (eddy current) is generated due to a change in magnetic flux passing through the heating unit, and the heating unit is induction heated. The heat medium in the pipe is heated by receiving heat from the heating unit.

  Examples of the conductive material used for the heating unit of the energy conversion device in the heat medium heating device include metals such as aluminum, copper, and iron.

  A permanent magnet or a coil (electromagnet) can be used as the magnetic field generating means of the energy conversion device. Specific examples of the coil include a normal conducting coil such as a copper wire and a superconducting coil. Since the induction heating energy (induction current) is proportional to the square of the magnetic field strength (H), it is preferable to use a coil capable of generating a stronger magnetic field than the permanent magnet as the magnetic field generating means. . In the case of using a coil, a strong magnetic field can be generated by increasing the current flowing through the coil, and the strength of the magnetic field can be adjusted by controlling the energizing current. 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. Furthermore, when a heat insulating material is provided around the heating unit in order to keep the heating unit warm, the heat insulating material is disposed between the magnetic field generating unit and the heating unit, and the distance between the magnetic field generating unit and the heating unit is increased. Even if there is, it is easy to maintain a sufficient magnetic field strength by increasing the energization current. Therefore, a magnetic field sufficient to heat the heat medium to a predetermined temperature (for example, 100 ° C. to 600 ° C.) can be obtained by using the coil as the magnetic field generating means. In addition, when using a coil, connecting a direct-current power supply to a coil and generating a direct-current magnetic field are mentioned.

  Furthermore, in the case of a superconducting coil, the electric resistance is zero, and even when a large current is passed, heat generation (loss) does not substantially occur in the coil. Therefore, compared with a normal conducting coil, heat generation (loss) of the coil due to flowing a large current can be suppressed, and a stronger magnetic field can be generated.

  On the other hand, when using compression heat, for example, it has a cylinder and a piston housed in the cylinder, and the reciprocating movement of the float causes the piston to reciprocate relatively with respect to the cylinder. For example, the heat medium can be heated by being transmitted to the heat medium. The piston may be either hydraulic or pneumatic.

  The heat medium heating device of the present invention does not require a link mechanism that changes the reciprocating motion into a rotational motion, and therefore has a simple structure and excellent maintainability, and heats the heat medium by utilizing the reciprocating motion of fluid existing in nature. Can do. Moreover, the power generation system of the present invention is a novel power generation system that does not use the heat of the heat medium heated by using the above-described heat medium heating device of the present invention for power generation.

It is a schematic diagram which shows the structure of the heat medium heating apparatus which concerns on Embodiment 1, (A) is an external view, (B) is a partially cutaway sectional view. It is a schematic diagram which shows an example at the time of forming the heating part and piping in the heat-medium heating device which concerns on Embodiment 1 with a different body. It is a schematic diagram which shows an example of the whole structure of the electric power generation system which concerns on this invention. It is a schematic diagram which shows the whole structure of the conventional wave power generator.

  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.

<Heat medium heating device>
(Embodiment 1)
A heat medium heating device 101 according to Embodiment 1 shown in FIG. 1 includes a float 20, a support column 25, and an energy conversion device 30. Hereinafter, the configuration of the heat medium heating apparatus 101 will be described in detail.

  The float 20 is a member that floats on the water surface such as the sea surface or a lake surface, and reciprocates according to the vertical vibration of the wave.

  The support column 25 is a member erected on the float 20 and has a magnetic field generating means 31 to be described later attached thereto.

  The energy conversion device 30 is a device that directly converts reciprocating kinetic energy into heat energy, and includes a magnetic field generation means 31 and a heating unit 35. The magnetic field generating means 31 is attached to the intermediate part of the support column 25. In this example, the magnetic field generating means 31 is a superconducting coil, and the support column 25 is formed of a nonmagnetic material.

  The magnetic field generating means (superconducting coil) 31 is wound around and attached to the outer periphery of the support column 25 along the axial direction of the support column 25. A DC power supply (not shown) is connected to the superconducting coil 31. In this example, the direction of the magnetic field (magnetic flux) to be generated is determined by controlling the direction of the current flowing through the superconducting coil 31, and one end side (float 20 side) is the S pole and the other end side is the N pole. (A dotted line arrow in FIG. 1B shows an image of magnetic flux flow). The superconducting coil 31 is covered with a cooling jacket (not shown), and is kept in a superconducting state by cooling.

  The heating unit 35 is provided outside the magnetic field generating unit 31 with a space from the magnetic field generating unit 31 and is formed in a cylindrical shape (specifically, a cylindrical shape) so as to cover the periphery of the magnetic field generating unit 31. Magnetic flux from the magnetic field generating means 31 passes through the heating unit 35. The heating unit 35 is made of a conductive material, and is formed of a metal such as aluminum, copper, or iron, for example. The heating unit 35 is fixed to, for example, a caisson (not shown) so as not to move with respect to the float 20 (magnetic field generating means 31).

  The heating unit 35 is provided with a pipe 40 through which a heat medium flows. In this example, a plurality of flow passages extending in the axial direction are formed inside the heating unit 35, and these are used for the piping 40 through which the heat medium flows. Each pipe 40 is connected to and communicates with a supply pipe 41 that supplies a heat medium from the outside and a discharge pipe 42 that discharges to the outside. The heating unit 35 and the pipe 40 are thermally connected. In this example, the heat medium is supplied from the lower side of the pipe 40 (float 20 side) and the heat medium is discharged from the upper side. However, the heat medium is supplied from the upper side and the heat medium is discharged from the lower side. You may do it.

  Further, a heat insulating material (not shown) may be disposed around the heating unit 35. For example, in this example, a heat insulating material may be provided on the inner and outer peripheral surfaces of the heating unit 35 (except for the connection portion with the supply pipe 41 and the discharge pipe 42) and on both end surfaces of the heating unit 35. 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 heat medium heating apparatus 101 is heated will be described in detail.

  When the superconducting coil 31 is energized, a magnetic field is generated, and the magnetic flux passes through the heating unit 35. Further, the float 20 reciprocates in accordance with the vertical vibration of the wave, and the magnetic field generating means 31 attached to the support column 25 reciprocates relative to the heating unit 35 by the reciprocating motion of the float 20. As a result, the magnetic flux passing through the heating unit 35 changes and an induction current (eddy current) is generated in the heating unit 35, whereby the heating unit 35 is induction-heated and the heat medium in the pipe 40 is heated.

  In the case where a coil (including a normal conducting coil and a superconducting coil) is used as the magnetic field generating means 31 of the energy conversion device 30, the lead wire of the coil may be connected to an external power source to supply a current.

  In the heat medium heating device 101 of the first embodiment described above, the case where the flow path is formed inside the heating unit 35 and the heating unit 35 and the pipe 40 are integrally formed has been described as an example. The pipe 40 may be formed separately. In that case, it is preferable that the pipe is also formed of a conductive material. By forming the pipe with a conductive material, the pipe can also be used as a heating unit. Moreover, a heating part and piping may be made into a different body, and piping may be provided in the surface of a heating part. Here, in the case where the pipe is formed of a conductive material and the pipe is also used as a heating unit, for example, the pipe may be provided on the surface of the cylindrical support base in addition to the pipe. At this time, the cylindrical support base may be formed of a material other than the conductive material.

  FIG. 2 is a diagram illustrating an example when the heating unit and the piping are formed separately. The pipe 40 of this example is wound around and attached to the outer peripheral surface of the heating unit 35 along the axial direction of the heating unit 35, and has a coil shape. If the piping is configured in this way, the heating distance of the heat medium can be increased. In this example, the pipe 40 is provided on the outer peripheral surface of the heating unit 35, but the pipe 40 may be provided on the inner peripheral surface of the heating unit 35. In addition, by providing a plurality of meandering pipes on any of the inner and outer peripheral surfaces of the heating unit 35, the heating distance of the heat medium can be increased.

  2 is made of a conductive material. Therefore, when the magnetic field generating means arranged inside the coil-shaped pipe 40 moves reciprocally relative to the pipe 40 by the reciprocating movement of the float, the magnetic flux penetrating the inside of the coil-shaped pipe 40 made of a conductive material. Also changes. Thereby, due to the change of the magnetic flux penetrating the inside of the coil-shaped pipe 40, an induced electromotive force is generated in the coil-shaped pipe 40, and the current flows through the pipe 40, whereby the pipe 40 is heated, The heat medium flowing through the pipe 40 is heated. Furthermore, in order to prevent the current generated in the pipe 40 from leaking to the outside through the pipe 40, the winding start and end ends of the pipe 40 may be electrically connected by a connecting conductor.

  The heat medium heating device according to the embodiment of the present invention described above uses a reciprocating motion of a fluid existing in nature and directly converts the reciprocating kinetic energy into thermal energy without converting it into rotational kinetic energy. The heating medium can be heated. Therefore, there is no need for a complicated link mechanism that changes reciprocating motion into rotational motion, and excellent maintainability can be realized with a simple structure. In addition, by adopting the superconducting coil, it is possible to suppress the loss of the coil due to flowing a large current and to generate a stronger magnetic field.

  Furthermore, since the heating unit (pipe) is fixed so as not to move, for example, a supply pipe or a discharge pipe (hereinafter collectively referred to as a supply / discharge pipe) that communicates with the pipe and supplies and discharges a heat medium from the outside. It is not necessary to use an expansion joint (flexible joint) that allows the pipe to reciprocate in connection with the pipe, and a robust connection can be realized by a simple method.

  When the heat medium is heated, the pressure in the pipe increases. For example, when the heat medium is water (steam), the pressure reaches about 250 MPa (250 atm) at 600 ° C. In the structure where the heating unit (pipe) is attached to the float and fixed so that the magnetic field generating means does not move, the connection between the supply / exhaust pipe and the pipe allows the pipe to reciprocate and withstand the pressure. Special expansion joints are required. However, in the structure in which the heating unit (pipe) is fixed so as not to move like the heat medium heating device 101 shown in FIG. 1, it is not necessary to use an expansion joint for connecting the supply / exhaust pipe and the pipe. A sufficiently robust connection can be realized by a simple method of welding the supply / discharge pipe and the pipe.

  In the heat medium heating device 101 of the first embodiment described above, the case where the induction heating method is used for the energy conversion device 30 has been described as an example, but it is also possible to use frictional heat. For example, instead of the magnetic field generating means 31 of the heat medium heating device 101 shown in FIG. 1, a sliding contact member that is in sliding contact with the heating unit 35 is attached to the float 20, and the sliding contact member and the heating unit are mutually connected by reciprocating movement of the float. It is conceivable to generate frictional heat by relatively reciprocating while sliding. However, in this case, one or both of the sliding contact member and the heating unit are worn by use, and therefore, it is necessary to periodically replace the parts.

<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. A power generation system P shown in FIG. 3 includes a heat medium heating device 10, a heat accumulator 50, and a power generation unit 60. Hereinafter, the configuration of the power generation system P will be described in detail.

  The heat medium heating device 10 is the heat medium heating device of the present invention, and for example, the heat medium heating device 101 according to the first embodiment described above can be used. Here, a case where the heat medium is water will be described as an example.

  A supply pipe 41 that supplies water to the apparatus 10 and a discharge pipe 42 that discharges water heated by the apparatus 10 are connected to the piping of the heat medium heating apparatus 10, and the apparatus 10 and the heat accumulator 50 are connected to each other. The water is circulated between them.

  In the heat medium heating device 10, a magnetic field is generated by the magnetic field generation means 31 of the energy conversion device 30, and the magnetic flux generated by the magnetic field generation means 31 passes through the heating unit. Further, the float 20 reciprocates in accordance with the vertical vibration of the wave, and the magnetic field generating means 31 reciprocates relative to the heating unit 35. And the magnetic flux which passes the heating part 35 changes with the vertical vibration of a wave, the heating part 35 is induction-heated, and the water in piping is heated. In addition, since the heating medium heating device 10 uses a coil as the magnetic field generating means 31, it can generate a strong magnetic field and can heat water as a heating medium to a high temperature such as 100 ° C. to 600 ° C. It is. Furthermore, since the heating medium heating device 10 has a structure in which the heating unit 35 (pipe) is fixed so as not to move, it is not necessary to use expansion joints to connect the supply pipe 41 and the discharge pipe 42 to the pipe. A robust connection can be realized by a simple method such as welding.

  The power generation system P heats water to a temperature suitable for power generation (for example, 200 ° C. to 350 ° C.) by the heat medium heating device 10 to generate high-temperature and high-pressure water. The high-temperature and high-pressure water is sent from the heat medium heating device 10 to the heat accumulator 50 through the drain pipe 42. The heat accumulator 50 stores the heat of the high-temperature and high-pressure water sent through the discharge pipe 42, 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 heat medium heating device 10 and the steam may be directly supplied to the power generation unit 60.

  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 steam turbine 61 can rotate the generator 62 at an arbitrary number of revolutions (for example, 3600 revolutions per minute).

  The high-temperature high-pressure water or steam sent to the power generation unit 60 (steam turbine 61) is cooled by, for example, a condenser and returned to water.

  According to this power generation system P, it is possible to generate power using natural energy (eg, wave power). Specifically, the reciprocating motion of a fluid existing in nature (eg, vertical vibration of a wave) can be directly converted into thermal energy and extracted as electrical energy. And, by converting the reciprocating kinetic energy into thermal energy and converting the thermal energy into electrical energy, for example, it is possible to generate power at an arbitrary frequency without using a speed increaser. A small and efficient power generation system can be realized.

  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.

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

  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.

  The heat medium heating device 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 natural energy. The power generation system of the present invention can be suitably used in the field of power generation using natural energy.

10,101 Heating medium heating device P Power generation system
20 Float 25 Support column
30 Energy converter
31 Magnetic field generation means (superconducting coil) 35 Heating section
40 Piping 41 Supply pipe 42 Discharge pipe
50 heat storage
60 Power generation section 61 Steam turbine 62 Generator
100 wave power generator
110 Float 120 Rod 130 Generator

Claims (4)

A float that reciprocates according to the reciprocating motion of the fluid that exists in nature,
An energy conversion device that converts the reciprocating kinetic energy of the float into thermal energy;
A heat medium that receives heat from the energy conversion device;
Bei to give a,
The energy conversion device includes a magnetic field generation unit, and a heating unit that is at least partially formed of a conductive material and through which the magnetic flux generated by the magnetic field generation unit passes.
Either one of the magnetic field generation unit and the heating unit is attached to the float, and the magnetic field generation unit and the heating unit reciprocate relatively by reciprocation of the float,
The heating medium is circulated, the heat medium heating device Ru comprising a pipe for heat from the heating unit. It said magnetic field generating means, the heat medium heating apparatus according to Oh Ru請 Motomeko 1 in superconducting coil. The heat medium heating apparatus according to claim 1, wherein the magnetic field generating means is a permanent magnet or a normal conducting coil. The heat medium heating device according to any one of claims 1 to 3,
Power generation system Ru comprising a power generation unit, the converting heat of the heating medium into electrical energy.

Images