Apparatus and method for generating electricity from moving fluids - Patents.com

Abstract

1. An apparatus for generating electricity from a moving fluid, comprising: an elongated body having a longitudinal axis, the elongated body being attached to the ground or seabed and arranged to be exposed to the moving fluid; at least one taut cable being supported in tension from the elongated body and at least partially disposed within the elongated body, and further arranged to oscillate or vibrate relative to the oscillation of the elongated body; and at least one energy harvester for converting kinetic energy of the oscillating or vibrating at least one taut cable into electrical energy.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention relates to the generation of energy from renewable resources, and in particular to an apparatus and related method for generating electricity from moving fluids. [background] There is an increasing desire to generate electrical energy from renewable resources such as wind and water. Wind turbines are widely used to harvest the kinetic energy of wind using rotatable blades that drive the turbine. The use of rotating blades to harvest wind energy has several drawbacks, including, for example, causing bird deaths, noise pollution, and disrupting residential landscapes. Rotating parts typically must handle large forces and stresses, which can limit their lifespan.

[0002] Various attempts have been made to generate electrical energy from wind without using rotating blades. A paper titled "On the efficiency of energy harvesting using vortex-induced vibrations of cables" by Grouthier, Michelin, et al., published in the Journal of Fluids and Structures (Volume 49, August 2014), discusses three configurations: the first includes an elastically mounted rigid cylinder moved by the wind; the second includes a tensioned cable with distributed energy harvesters attached; and the third includes a suspended cable with a single energy harvester. The study aimed to compare the three configurations in terms of their ability to harvest energy from low-velocity geophysical flows. [Summary of the Invention] According to a first aspect of the present invention there is provided an apparatus for generating electricity from a moving fluid, the apparatus comprising: an elongated body having a longitudinal axis, the elongated body being attached to the ground or seabed and positioned to be exposed to a moving fluid; at least one tensioned cable supported in tension by the elongated body, disposed at least partially within the elongated body, and arranged to oscillate or vibrate in response to oscillation of the elongated body; at least one energy harvester for converting kinetic energy of at least one oscillating or vibrating tensioned cable into electrical energy; It is equipped with:

[0003] The elongated body may, in use, be attached to the ground. The elongated body may, in use, extend vertically upwards from the ground. The elongated body may be wholly or partly located underwater. The elongated body may be secured to a floating body, such as a barge secured to the ground or seabed. The moving fluid may be or include any of water, air, and gas.

[0004] Typically, the at least one tensioned cable is at least partially disposed along the longitudinal axis. Typically, all of the at least one tensioned cable is disposed along the longitudinal axis.

[0005] Typically, the at least one energy harvester comprises at least one magnet and at least one coil. Typically, the first ends of the tensioned cables are attached to the elongated body, which may be advantageous in that kinetic energy of the elongated body can be transferred to the at least one tensioned cable to cause the at least one tensioned cable to oscillate relative to both the elongated body and the ground or seabed. The oscillating motion of the at least one tensioned cable may be converted into electrical energy using at least one magnet and at least one coil.

[0006] The at least one magnet may be moved by at least one tensioned cable and move relative to the at least one coil. The at least one coil may be attached to the ground or the seabed and be stationary relative to the ground or the seabed. The at least one coil may be connected to the elongated body.

[0007] Typically, the elongate body comprises a cylindrical structure arranged to be exposed to the fluid in use. A cylindrical structure may be advantageous in that it may induce vortex forces as fluid passes through the elongated body, which may cause the elongated body to move. The elongated body may have a generally tapered shape.

[0008] Typically, one end of the elongated body may be fixedly attached to the ground in use, and the elongated body may extend further vertically from the ground and be exposed to the wind. Typically the device further comprises damping means which, in use, may be attached to the lower end of the elongate body.

[0009] The damping means may prevent fatigue of the elongate body. Typically, at least one tensioned cable has one end fixedly secured to the elongate body.

[0010] Typically, at least one taut cable has another end fixedly fastened to or near the ground. Anchoring the second end to or near the ground can be advantageous in that it can provide a substantially stationary anchor point for one end of the at least one taut cable. When the first end of the at least one taut cable is moved by the elongate body, this imparts a wave that moves along the at least one taut cable. By anchoring the at least one taut cable stationary, the wave is reflected, conserving kinetic energy.

[0011] Typically, at least one energy harvester is located within the elongate body. Typically, the device further comprises a support for supporting at least a portion of the energy harvester, the support being disposed within the elongate body and extending along the longitudinal axis.

[0012] The support may have one end fixed to the ground in use, and the at least one coil may be attached to the support. The support may be advantageous in that it may provide stationary support for the at least one coil within the elongated body, so that the at least one magnet may move relative to the at least one coil.

[0013] Typically, the at least one energy harvester further comprises vibration harvesting means for harvesting at least a portion of the kinetic energy of the at least one taut cable.

[0014] The vibration harvesting means may be attached to at least one taut cable. The vibration harvesting means may have a mass of 0.1 kg or more. The energy harvesting means may have a mass of 1 kg or less. The energy harvesting means may have a mass of 1 kg or more. The energy harvesting means may have a mass of 5 kg or less. A mass greater than 0.1 kg may be advantageous in that the mass may possess sufficient inertia that may result in a more stable oscillation of the vibration harvesting means when moved by the oscillating cable.

[0015] Typically, the at least one energy harvester further comprises vibration harvesting means comprising at least one magnet and conversion means comprising at least one coil, the vibration harvesting means being moved by at least one tensioned cable and arranged to move relative to the at least one coil. The coil may be a horizontal coil or a vertical coil. The coil may be fixedly arranged on the support. For example, the coil may be integrated into the wall structure of the support. A horizontal coil may be wound around a horizontal axis, and the vibration harvesting means may be configured to allow the magnet to move in a direction along the horizontal axis, for example in a central region of the coil. A vertical coil may be wound around a vertical axis, and the vibration harvesting means may be configured to allow the magnet to move in a direction approximately parallel to the windings of the coil. Advantageously, multiple coils with multiple vertical axes may be provided at various positions around a circle, allowing the multiple magnets to oscillate horizontally, allowing direct-drive conversion of vibrations into electrical energy in the multiple coils, thereby enabling conversion in multiple directions without the need to adjust the orientation of the device in response to changes in wind direction.

[0016] Typically the vibration collection means further comprises a first collection means and a second collection means, the first and second collection means arranged to convert horizontal movement into vertical movement, the first collection means being fixed to at least one taut cable and the second collection means being attached to a support and arranged to move vertically in use.

[0017] Typically, the support is fixed to the ground and arranged to be stationary relative to the elongated body. Converting horizontal motion to vertical motion can be advantageous in that the energy harvester can harvest any horizontal oscillation and convert it into a single directional oscillation, i.e., vertical oscillation. As the magnet oscillates vertically, it can induce a current in a coil attached to the support. This can avoid having to adjust the orientation of the device in response to changes in wind direction. Typically, the support is an inner portion of the elongated body or is attached to the elongated body.

[0018] According to a second aspect of the present invention there is provided a method of generating electrical energy from wind by use of an apparatus according to the first aspect of the present invention. [Detailed explanation] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0019] [Figure 1] 1 shows a device for generating electricity from wind. [Figure 2] 1 shows a vertical cross section of the device with a detailed view of the end cap. [Figure 3] 1 shows a detailed vertical cross section of the energy harvester. [Figure 4] 4 shows a vertical cross section of FIG. 3 slightly rotated. [Figure 5] 10 shows a vertical cross section of an alternative embodiment of an energy harvester. [Figure 6] 1 shows a schematic diagram of an alternative embodiment of an energy harvester. DETAILED DESCRIPTION OF THE INVENTION

[0020] As used herein, the terms lateral and horizontal are used to identify directions that are primarily horizontal. The term vertical is used to indicate directions that are primarily vertical. Upward, downward, vertical, and horizontal are used to indicate orientations of the device 100 when the device 100 is placed vertically on the ground. Similarly, upward and downward refer to the harvester 100 when the harvester 100 is placed vertically on the ground.

[0021] The device 100 shown in Figure 1 comprises an elongated body 1 and a base 2. The base 2 is fixedly attached to the ground 9. The elongated body 1 is attached to the base 2 and extends vertically upward from the base 2 between a first end and a second end of the elongated body 1. The elongated body 1 is arranged to vibrate or sway when exposed to wind.

[0022] As shown in FIG. 2 , the device 100 further includes a tensioned cable 5 disposed within the elongated body 1. The tensioned cable 5 may be a wire, a rope made of polymer or organic fiber, or any non-rigid wire, string, cable, or rope that can vibrate or swing. The tensioned cable 5 has a first end 51 attached to the elongated body 1 at or near its top end and a second end 59 attached to the base 2. The elongated body 1 is positioned to induce vibration of the tensioned cable 5. An energy harvester 6 is disposed within the elongated body 1 for converting kinetic energy, i.e., the vibration of the tensioned cable 5, into electrical energy.

[0023] Referring again to Figure 1, the elongated body 1 has a generally cylindrical shape, i.e., a cylindrical structure 12. The cylindrical structure 12 has a longitudinal axis X1. An elongated cavity 122 is disposed coaxially with the axis X1. The elongated body further includes an end cap 11 fixedly attached to an upper end 121 of the cylindrical structure 12, thereby closing the upper end of the cylindrical structure 12 and sealing the cavity 122.

[0024] The base 2 includes a cylindrical housing 21 and a foundation 29, and the base can be connected to the ground via the foundation 29. In this embodiment, the foundation 29 includes a circular plate 291 having holes (not shown) for fixing the foundation 29 of the base 2 to the ground 9. The circular plate 291 is horizontally fixed to the ground 9. The cylindrical housing 21 is attached to the foundation 29 by concentrically joining and fixing the housing 21 onto the plate 291. The diameter of the cylindrical housing 21 is adjusted to surround the lower part of the cylindrical structure 12 of the elongated body 1, thereby fixing the elongated body 1 to the base 2. The cylindrical structure 12 and the cylindrical housing 21 form a continuous hole along the axis X1. In this embodiment, the cylindrical housing 21 includes a damping means 211 for preventing fatigue of the cylindrical structure 12. In this embodiment, the damping means 211 includes a cylindrical metal bellows 212. 2, a metal bellows 212 is attached to the lower portion 219 of the cylindrical housing 21 by a flange connection 215. In other embodiments, such damping means 211 is not used or is not necessary.

[0025] 2 shows the first end 51 of the tensioned cable 5 disposed within the cavity 122 of the elongated body 1. The end cap 11 includes a cable tensioning section 13 having a piston head 131 movable within the end cap 11 along the longitudinal axis X1. A fluid passage 132 is disposed within the end cap 11 for biasing the piston 121 upward. A nut 111 and a bolt 112 are connected to the upper end of the piston head 131 to secure the first end 51 to the end cap 11, allowing the piston 131 to be used to adjust the tension of the cable 5.

[0026] 2 further shows the second end 59 of the tensioned cable 5 attached to the base 2, thereby providing a stationary fixed point for the second end 59 of the tensioned cable 5. Thus, the cable 5 is tensioned between a fixed point at the upper end and a fixed point at the lower end.

[0027] In some embodiments, the cable tensioning portion 13 is located in the base 2 of the device, where the first end 51 is fixedly fastened to the end cap and the second end 59 is fixed to a piston head 131 within the base 2. Having the cable tensioning portion 13 within the base allows for easy adjustment of the tension in the taut cable 5.

[0028] In use, wind passes through the cylindrical structure 12, changing the pressure around the cylindrical structure 12 and moving the elongated body 1, causing the elongated body 1 to oscillate, moving its upper end back and forth. This oscillating motion acts on the first end 51, imparting a wave-like motion to the taut cable 5. This causes the taut cable 5 to move or vibrate relative to both the ground 9 and the elongated body 1. This relative motion can be used to generate electrical energy using one or more energy harvesters 6 located within the elongated body 1.

[0029] 3 and 4 show the energy harvester 6 in more detail. The energy harvester 6 is arranged to convert the movement of the taut cable 5 into electrical energy. The energy harvester 6 comprises a cylindrical support 69 rigidly attached to the base 2, as shown in FIG. 2. In this embodiment, the support 69 extends approximately halfway along the elongated body 1. In other embodiments, the support 69 may be at another position along the elongated body 1.

[0030] The energy harvester 6 further comprises vibration harvesting means 60 and conversion means 65 for converting kinetic energy into electrical energy. The vibration harvesting means 60 comprises a first harvesting means 61 and a second harvesting means 62 arranged within a support 69. The first harvesting means 61 is arranged to harvest horizontal vibrational energy by moving horizontally with the taut cable 5. The horizontal movement of the first harvesting means 61 is converted into vertical movement of the second harvesting means 62 by using oppositely oriented magnets.

[0031] The first collection means 61 is attached to the tensioned cable 5 such that it can move laterally as the tensioned cable 5 moves laterally. The first collection means 61 includes a disk 611 and three first magnets 612 secured to the disk 611. The tensioned cable 5 extends through the center of the disk 611 secured to the tensioned cable 5, so that the disk 611 moves with the tensioned cable 5. The first magnets 612 are spaced apart on the disk 611 and are arranged with one pole facing upward and the opposite pole facing downward. The first collection means 61 further includes a first ring 619 surrounding the inner periphery of the support 69. The first ring 619 is secured to the support 69. The disk 611 is connected to the first ring 619 via a plurality of elastic bands 615.

[0032] The second collection means 62 is supported within the support 69 above the first collection means 61. The second collection means 62 further extends around the taut cable 5 and has a hole through its center positioned to allow free lateral movement of the taut cable 5 as it vibrates. The second collection means 62 also includes three second magnets 622 oriented in the opposite direction to the first magnets 612. As a result, as the taut cable 5 moves, the first magnets 612 are moved away from the second magnets 622, changing the repulsive forces between opposing pairs of the first magnets 612 and second magnets 622, converting lateral movement of the taut cable 5 into vertical movement of the second collection means, as will be further explained.

[0033] The second collection means 62 comprises a central ring-shaped structure 620 to which an arm 621 is attached. The arm 621 has one or more magnets 623 attached to its outer portion. The second collection means 62 further comprises a circular support structure 629 fixedly mounted to a support 69. The support structure 629 has a hole through its center, through which the cable 5 can move freely. The ring-shaped structure 620 is attached to the lower part of the support structure 629 via four springs 625. The springs 625 are arranged around the longitudinal axis X1 and can compress or expand in a direction along the axis X1 to allow vertical movement of the second collection means 62.

[0034] The first collection means 61 is said to be centered when the center of the disk 611 is aligned with the longitudinal axis X1. The magnets 612 and 622 are positioned such that when the first collection means 61 is centered, each first magnet 612 has the second magnet 622 directly above it, i.e., their central axes are aligned. The second magnet 622 is oriented in the opposite direction to the first magnet 612 so that the first magnet 612 and the second magnet 622 repel each other. This repulsive force increases as the magnets are closer together and decreases as the first magnet 612 is moved away.

[0035] As the taut cable 5 swings or vibrates, the first magnet 612, being part of the first collection means 61, moves horizontally. The second magnet 622 observes a changing magnetic field, which moves the second collection means 62 vertically. Because the orientations of the first magnet 612 and the second magnet 622 are opposite, as the first collection means 61 approaches the center of the support 68, the second collection means 62 is pushed upward. As the first collection means 61 moves away from the center of the support 68, gravity and / or the spring 625 pull and / or push the second collection means 62 downward. In this way, any horizontal movement of the taut cable 5 and first collection means 61 is translated into vertical movement of the second collection means 62.

[0036] The conversion of the vertical movement of the second collecting means 62 into electrical energy is achieved by the magnet 623 of the second collecting means 62 moving relative to the converting means 65. The converting means 65 is disposed within the support 69 at the same height as the magnet 623. The converting means 65 comprises a second ring 650 surrounding the periphery of the support 69. The converting means 65 further comprises a plurality of coils 692 arranged circumferentially inside the second ring 650. The coils 692 are oriented such that the central axis of each coil is parallel to the tangent to the periphery of the second ring 650, as shown in FIGS. 3 and 4 . Furthermore, the coils 692 are disposed such that each magnet 623 extends into the space between two adjacent coils 692.

[0037] As shown, this embodiment of the energy harvester 6 includes another set of second harvesting means 62′ and conversion means 65′ disposed below the first harvesting means 61 within the support 69. This set operates in a similar manner, except that it is flipped 180 degrees compared to the second harvesting means 62 and conversion means 65. Having two sets of second harvesting means 62 and conversion means 65 can be advantageous in that the first magnet 612 can observe the opposing magnetic force and prevent vertical movement of the first harvesting means 61.

[0038] When the second collection means 62 oscillates perpendicularly to the coil 692, the varying magnetic field induces a current in the coil 692. The coil 692 is connected to a battery (not shown) or an electrical grid (not shown) so that electricity can be utilized. Facilities for producing hydrogen gas by electrolysis from the generated electricity may also be employed.

[0039] Multiple energy harvesters 6 can be used within the elongated body 1. Preferably, the placement of the energy harvesters 6 is based on the wave propagation pattern on the tensioned cable 5. Furthermore, the tension of the tensioned cable 5 can be changed to adjust the oscillation pattern. In some embodiments, the tension of the cable 5 can be adjusted so that the energy harvester 6 generates a standing wave located near an antinode of the standing wave, i.e., midway between two nodes. If the average wind speed results in one antinode, typically one energy harvester 6 is used, located in the center of the cavity 122. If two antinodes are present, two energy harvesters 6 are used, one in the first third of the cavity 122, one in the second third of the cavity, etc.

[0040] The arrangement of the energy harvester 6 as described above with reference to the drawings allows the vibration of the cable 5 in any horizontal direction to be converted into a movement in one direction, i.e., vertically, thereby making it possible to generate electrical energy regardless of the wind direction or the swing direction of the elongated body 1.

[0041] In another embodiment, the energy harvester 6 is arranged to convert the horizontal movement directly into electrical energy, see Figures 5 and 6. This arrangement is shown in FIG. 5, in which the energy harvester 6 includes a horizontal magnet body 71 and a coil arrangement 72. The center of the horizontal magnet body 71 is attached to the taut cable 5. The magnet body 71 is elongated horizontally, with two magnets 711 attached, one at each end of the magnet body 71. The coil arrangement 72 includes two coils 721 attached to the support 69. The coil arrangement 72 houses each of the magnets 711 and is positioned to generate electricity when the magnet body 71 moves with the taut cable 5. The energy harvester 6 in this embodiment requires the taut cable 5 to move in a single direction, defined by the orientation of the coils 721. An arrangement for rotating the support 69 can be employed to adjust for various wind directions. The coils 721 in this embodiment are horizontal coils.

[0042] Another arrangement for this is shown in FIG. 6 , in which the energy harvester 6 includes a horizontal magnet body 71 and a coil device 72. The center of the horizontal magnet body 71 is attached to the taut cable 5. The magnet body 71 is elongated horizontally, with two magnets 711 attached, one at each end of the magnet body 71. The coil device 72 includes multiple coils 721 attached to the support 69. In this example, the coils 721 are vertical coils with windings around a vertical axis. As the magnet body 71 moves with the taut cable 5, the magnets 711 pass through the regions 731 between the coils 721, generating electricity. The horizontal movement of the magnet body 71 allows the magnets 711 to interact with the coil device 72. In contrast to FIG. 5 , the energy harvester 6 in the example of FIG. 6 does not require the taut cable 5 to move in one direction because the magnets are not constrained by the coils 721 when in the regions between the coils.

[0043] The device 100 can also be used to generate electrical energy from water currents and waves. When placed underwater, the forces acting on the elongated body 1 can be stronger than when exposed to wind. Therefore, the dimensions of the cylindrical structure 12 can be smaller, and the elongated body 1 can be fixed at both ends. In this case, two taut cables 5 can be disposed within the elongated body 1, with first ends 51 of the two taut cables 5 fixed to the middle of the elongated body 1 and the two cables 5 extending in opposite directions along the elongated body. The elongated body 1 can also extend horizontally, vertically, or in any direction suitable for capturing energy from water. In some embodiments, multiple taut cables 5 can be disposed transverse to the longitudinal axis X1 of the elongated body. In this case, both ends of the multiple taut cables 5 are fixed inside the cylindrical structure 12. When the cylindrical structure 12 is moved by passing water, both ends of the taut cables 5 are moved. In this embodiment, a number of energy harvesters 6, one for each of the tensioned cables 5, are arranged on a rigid rod extending along the longitudinal axis X1 within the cylindrical structure 12.

[0044] In some variations, the single taut cable 5 need not pass through the energy harvesting means, but may be replaced by a first cable extending from a first fixed point at the end cap to the first energy harvesting means, and a second cable extending from the first energy harvesting means to a second fixed point at the base. It will also be apparent that the energy conversion can be configured in various ways using a cable having an energy transforming device thereon, where the rocking of the cylindrical elongated body causes the cable having the energy transforming device thereon to vibrate.

Claims

1. 1. An apparatus for generating electricity from a moving fluid, comprising: an elongated body having a longitudinal axis, the elongated body being attached to the ground or seabed and positioned to be exposed to the moving fluid; at least one taut cable supported in tension from and at least partially disposed within said elongated body, and further arranged to oscillate or vibrate in response to oscillation of said elongated body imparting an undulating motion to said at least one taut cable, such that said at least one taut cable moves or vibrates relative to both said ground and said elongated body; at least one energy harvester for generating electrical energy using the movement of the at least one taut cable oscillating or vibrating relative to both the ground and the elongated body; The device is provided with:

2. 10. The apparatus of claim 1, The at least one tensioned cable is disposed at least partially along the longitudinal axis.

3. The device according to claim 1, The at least one energy harvester at least one magnet; At least one coil; The device is provided with:

4. The device according to claim 1, The device, wherein the elongated body comprises a cylindrical structure arranged to be exposed to the fluid in use.

5. The device of claim 1, One end of the elongated body is fixedly attached to the ground when in use, The elongated body further extends vertically from the ground and is exposed to wind.

6. The device of claim 1, The at least one tensioned cable has one end fixedly secured to the elongate body.

7. The device of claim 1, The at least one taut cable has another end fixedly fastened to or near the ground.

8. The device of claim 1, further comprising: a support for supporting at least a portion of the at least one energy harvester; The support is disposed within the elongate body and extends along the longitudinal axis.

9. The device of claim 1, The at least one energy harvester further comprises vibration harvesting means for harvesting at least a portion of the kinetic energy of the at least one taut cable.

10. 4. The apparatus of claim 3, the at least one energy harvester further comprises vibration harvesting means for harvesting at least a portion of the kinetic energy of the at least one taut cable; the vibration collecting means comprises the at least one magnet; the at least one energy harvester further comprises a conversion means including the at least one coil; The vibration collection means is moved by the at least one tensioned cable and is arranged to move relative to the at least one coil.

11. 11. The apparatus of claim 10, The apparatus, wherein the at least one coil is a vertical coil or a horizontal coil.

12. 9. The apparatus of claim 8, the at least one energy harvester further comprises vibration harvesting means for harvesting at least a portion of the kinetic energy of the at least one taut cable; The vibration collecting means further includes a first collecting means and a second collecting means; said first and second collection means being arranged to convert horizontal movement into vertical movement; the first collection means is fixed to the at least one taut cable; The second collection means is attached to the support and arranged for vertical movement in use.

13. The apparatus of claim 8, The support is fixed to the ground and positioned so as to be stationary relative to the elongated body.

14. A method for generating electrical energy from wind by using a device according to any one of claims 1 to 13.

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