A power generation and / or energy storage device

Abstract

A power generation and / or energy storage device comprises a buoyant flywheel (1), wherein the flywheel is configured, in use, to contact a body of liquid so as to rotate about a substantially vertical axis, the underside of the flywheel comprising a circumferentially extending opening (82), wherein, in use, gas is trapped in the opening by the surface of the liquid to define an air cushion for supporting the flywheel.

Description

Technical Field

[0001] The present invention relates to a power generation and / or energy storage device, and in particular to a system utilizing a buoyancy flywheel. Background Art

[0002] There is a well-publicized, long-term plan worldwide to move away from fossil fuel-generated electricity to more environmentally friendly alternatives. Renewable energy sources such as wind and solar clearly have the potential to reduce reliance on fossil fuels. Concerns about climate change, among other factors, have led to an increase in the deployment of both technologies. Both solar PV and wind power have intermittent output. It is understood that since the majority of the grid’s energy comes from these sources, the variability of these sources raises concerns about grid reliability. It is well known that energy storage will be an important component of future energy systems, especially as reliance on renewable energy sources increases.

[0003] There are several existing methods of storing electrical energy, including pumped hydro, batteries, compressed air storage and flywheels.

[0004] The present invention is the result of work related to providing improved energy generation and / or storage devices. Summary of the invention

[0005] In one aspect, the present invention provides a power generation and / or energy storage device comprising a buoyant flywheel, wherein the flywheel is configured to be in contact with a liquid to rotate about a substantially vertical axis when in use, and the underside of the flywheel comprises an opening extending substantially circumferentially, wherein, in use, gas is trapped in the opening by the surface of the liquid to define an air cushion for supporting the flywheel.

[0006] By this configuration, the flywheel is configured to float on the surface of the air cushion in use. The contact between the flywheel and the liquid provides a fluid seal for the air cushion. The liquid can be water in an open area, such as a sea or a lake, or can be included in a suitable groove or other. The opening can face the liquid so that the air cushion is supported by the surface of the liquid, otherwise it can face a supporting surface other than the liquid so that the air cushion is supported by the supporting surface. In a further configuration, it can face a supporting surface other than the water body and a water body. Regardless of the structure, the flywheel is stable in pitch and roll by contact with the liquid. The contact with the liquid body is preferably through one or more circumferential subordinate walls, wherein stability is achieved by moving one or more circumferential subordinate walls into the liquid body.

[0007] The gas is most preferably air. The liquid is most preferably water. The opening preferably extends substantially continuously around the entire circumference of the flywheel.

[0008] According to this configuration, the flywheel is supported on one or more air cushions, most preferably on air cushions. The air cushions act to reduce friction. Furthermore, in the case of open water installations, any wave-induced motion is effectively reduced. By introducing more gas, the volume of the air cushion and the traction of the flywheel can be maintained or restored. This can be achieved by using an air compressor.

[0009] Although as mentioned above, the gas is not limited to air, for simplicity, the following description will focus on the arrangement of an air cushion. However, it must be recognized that any of the described configurations can be appropriately modified to use gases other than air, as will be readily appreciated by those skilled in the art.

[0010] An embodiment provides a large floating horizontal flywheel that stores mechanical energy by rotating about its vertical axis. It can function to store self-generated power and / or to store converted electrical energy imported from elsewhere as rotational mechanical energy. This mechanical energy can then be converted back into electrical energy as needed and delivered to the end user via a cable. Alternatively, this electricity can be used for other purposes. For example, it can be used on or near the device to produce hydrogen by electrolysis, which can then be exported to the end user via a pipeline, if desired, along with the co-produced oxygen in a separate pipeline.

[0011] For spontaneous wind energy, the flywheel may be provided with a plurality of sails attached thereto.

[0012] Embodiments including very large flywheels have the potential to store, generate, and output energy on the order of gigawatts.

[0013] According to one or more embodiments, the device can be set up in offshore and open waters, and can also be moored to the seabed. In alternative embodiments, it can float in a circular tank on land, or be implemented in other ways.

[0014] In a preferred configuration, for installation in open water, the overall dimensions of the flywheel may be sufficiently large compared to the incident wavelength so that the effects of incident waves on the pitch and roll motions of the flywheel are substantially attenuated and kept to a minimum. The characteristic minimum overall dimensions to achieve such attenuation may be, for example, about 1500 meters in open water where a typical wave spectrum prevails.

[0015] Basic gyroscopic stabilization is a feature of various embodiments, which benefits performance.

[0016] The flywheel may be substantially annular. The flywheel may include a cover which is airtight and closes the center of the torus. The cover may include a disc which may be honeycomb-shaped or may include a frame enclosed by a skin which may include steel, concrete, glass reinforced plastic or airtight fabric. The lid may close the opening.

[0017] Regardless of its form, the flywheel may include a pair of spaced circumferential walls that are suspended from the flywheel in use, with an opening disposed between the walls. One of the circumferential walls may be a peripheral wall, or both walls may be spaced radially inwardly from the periphery of the flywheel. Alternatively, the flywheel may include a single circumferential wall that is suspended from the flywheel in use, with the opening provided by the circumferential wall. The circumferential wall may be disposed at the periphery of the flywheel, or may be spaced radially inwardly from the periphery of the flywheel. In use, the circumferential wall is preferably substantially vertical. In use, the circumferential wall preferably penetrates the surface of the liquid. This penetration will provide an immersed surface that supports the flywheel on the surface of the liquid. As described above, by moving the circumferential wall into the liquid, pitch and roll may be stabilized.

[0018] In such an offshore embodiment, the surface friction between the rotating submerged surface and the surrounding water will generate a circulating vortex. This can further provide further energy storage capacity that can be utilized, and will serve to reduce surface friction due to the reduction in relative speed between the submerged surface and the water of the rotating vortex.

[0019] The device according to various embodiments is semi-transparent to waves because most of the energy of the incident wave will propagate under the wall and through the lowered water surface defining the underside of the air cushion, and then propagate back into the open water under the subsequent wall, thereby reducing the incident wave force. When a wave passes under the flywheel in this manner, the air displaced by the crest of the wave in the air cushion simply moves into the trough of the wave, with virtually zero change in air pressure on the structure. This can be characterized by the decoupling observed that the flywheel behaves hydrostatically and hydrodynamically as if it were a semi-submersible platform supported by an air cushion but stabilized by its surface penetrating elements / walls, thus embodying a decoupling of buoyancy and stability.

[0020] The presence of the air cushion and the minimal bending moment created by the buoyancy of the surface penetrating elements acting as support allow for a relatively light structure.

[0021] The flywheel may be made of any suitable material, for example, without excluding other materials, steel or concrete. The preferred embodiment is made of post-tensioned concrete.

[0022] The flywheel may have a compartment / cell structure whereby the compartments / cells may be ballasted with water. Ballasting the cells may increase the extreme second moment of inertia of the flywheel, thereby increasing its energy storage capacity for any given angular velocity.

[0023] The water in the ballasted unit may be under considerable centrifugal pressure, where the water may be released tangentially to regenerate electrical energy.

[0024] In some embodiments, enhanced stability to damage may be achieved by maintaining an appropriate number of cells that are not flooded and / or by installing circumferential dividers of air cushions.

[0025] The fluid seal may comprise a segmented labyrinth.The labyrinth may be formed of a plurality of interlocking units, each interlocking unit being formed of a slave wall depending from the flywheel 1 and a facing wall protruding opposite the slave wall.

[0026] According to one or more embodiments, electrical energy imported from elsewhere may be reversibly converted by the stationary plant into rotational mechanical energy for storage by the flywheel at an interface between the stationary plant and the flywheel, thereby causing the flywheel to rotate.

[0027] According to one or more embodiments, electrical energy input from elsewhere may be conducted to the flywheel, where it is reversibly converted into rotational mechanical energy by a device carried on the flywheel for storage by the flywheel and thereby causing the flywheel to rotate.

[0028] According to one or more embodiments, a flywheel mounted facility may convert wind energy directly into rotational mechanical energy for storage in the flywheel and thereby cause the flywheel to rotate.

[0029] According to one or more embodiments, a device mounted on a flywheel can reversibly convert rotational fluid dynamic energy from surrounding water directly into rotational mechanical energy for storage by the flywheel and thereby cause the flywheel to rotate.

[0030] Furthermore, preferred features are presented in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Embodiments of the invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0032] Figure 1 shows a plan view and a cross-sectional view of an energy storage device according to a first arrangement;

[0033] Figure 2 Shown along Figure 1 The line AA in the Figure 1 a partial enlarged cross-sectional view of a flywheel of the device shown;

[0034] Figure 3 Shown as Figure 2 View A and View B shown in detail in FIG.

[0035] Figure 4 shows an enlarged partial cross-sectional view of an energy input / output configuration through a flywheel;

[0036] Figure 5 and Figure 6 Additional energy input / output configurations are shown;

[0037] Figure 7 , Figure 8 and Fig. 9 Different ballast configurations and mooring configurations are disclosed;

[0038] Fig.10 A. Fig.10 B and Fig.10 C shows cross-sectional views of three different flywheel configurations;

[0039] Fig.11 A and Fig.11 B shows a different onshore configuration;

[0040] Fig.12 A and Fig.12 B shows different sail configurations;

[0041] Fig.13 , Fig.14 , Fig.15 A. Fig.15 B. Fig.16 , Fig.17 and Fig.18 A. Fig.18 B and Fig.18 C is open Fig.12 A and Fig.12 Different configurations of B’s sail structure;

[0042] Fig.19 and Fig. 20 A typical configuration for enhanced damage stability is shown;

[0043] Fig.21 A cross-sectional elevation view showing a preferred optimized flywheel configuration;

[0044] Fig. 22 Shows Fig.21 Plan view of the flywheel;

[0045] Fig.23 Shows Fig.12 A and Fig.12 The preferred optimal configuration C of B; and

[0046] Fig.24 A partial cross-sectional view of a preferred sealing arrangement is shown. DETAILED DESCRIPTION

[0047] Generally speaking, embodiments of the present invention provide an apparatus for generating and / or storing energy that includes a novel buoyant flywheel.

[0048] It should be noted that although it is assumed herein that the flywheel rotates clockwise, counterclockwise rotation of the flywheel is also acceptable, which is easily understood by those skilled in the art.

[0049] Figure 1 A device for generating and / or storing energy according to a first embodiment is shown. The device comprises an annular flywheel 1 .

[0050] The flywheel 1 is buoyant and, in use, is arranged to contact the surface of a liquid, with the underside of the flywheel facing the surface of the liquid. The flywheel is arranged to rotate about a substantially vertical axis. The underside comprises an opening 2 extending circumferentially. In use, gas is trapped in the opening by the surface of the liquid. Thereby an air cushion is provided, which is used to provide support for the flywheel 1 and, as mentioned above, provides significantly reduced rotational friction.

[0051] In this arrangement, preferably the circumferential opening extends substantially continuously around the entire circumference of the flywheel 1. Alternatively, it may comprise a plurality of separate parts as discussed further below.

[0052] In this arrangement, as best shown in cross-section AA, the flywheel comprises a pair of spaced circumferential walls 3, 4 which in use depend from the flywheel 1, with an opening provided between the walls. In this arrangement, a deck 5 extends between the walls and closes the upper side of the opening 2. The deck is closed to trap gas within the opening.

[0053] As shown, in use, the walls are preferably vertically depending.In use, the circumferential walls 3, 4 penetrate the surface of the liquid, wherein the circumferential walls 3, 4 thereby define a support surface for the flywheel 1.

[0054] With this arrangement, in use, the flywheel is arranged to float on the surface of the air cushion formed in the opening 2. The flywheel provides a seal for the air cushion by contacting the liquid with the circumferential walls 3, 4. The flywheel 1 is stabilized in pitch and roll by contacting the liquid with the circumferential walls 3, 4 moving into the liquid. The opening 2 faces the liquid. In an onshore arrangement, for example, as described below with reference to Fig.11 and Fig.24 The opening 2 may face a solid support surface, such as the ground or a platform.

[0055] The flywheel 1 of the present device has a depth Z, a deck width X and an inner diameter Y. As will be appreciated by those skilled in the art, increasing any of these dimensions will increase the Polar Second Moment of Inertia of the flywheel 1, thereby increasing its energy storage capacity at any given angular velocity.

[0056] refer to Figure 1 , showing some exemplary and non-limiting external power input / output systems 6. It should be noted that Figure 1The embodiments are not limited to the presence or manner of these facilities discussed in the following paragraphs, and various alternative configurations may be adopted as understood by those skilled in the art.

[0057] When the flywheel rotates, a typical energy generation module will remain stationary in the global coordinates. The relative motion between the energy generation module and the flywheel will generate electricity or increase rotational mechanical energy by any suitable conventional means, such as but not limited to a wheeled bogie connected to a generator / motor, which is carried on the inner surface of the energy generation module and supported on the outer surface of the flywheel. Alternatively, as required by the situation, a row of excitation coils or permanent magnets around the circumference of the flywheel is opposite to the power generation or power supply coils on the inner surface of the energy generation module to form a generator or motor. Another preferred alternative is a circular magnetic levitation track, which has a dual purpose, in addition to bearing part or all of the total weight supported on the air cushion, so that the air cushion depth is reduced, the size of the attached wall is reduced, and the friction loss is reduced, it is also used to convert the input electrical energy into rotational mechanical energy for storage, and vice versa. Those skilled in the art will easily think of many suitable configurations, and the present invention is not limited in this regard.

[0058] The energy generating modules may be supported on suitable wheeled bogies or bearings, for example by tracks or ledges around the outer circumference of the flywheel, to allow free relative circular motion, as well as freedom to allow vertical movement of the energy generating modules carried by the flywheel.

[0059] Alternatively, when electrical energy is generated at a flywheel for output, or input to a flywheel for conversion to rotational mechanical energy at the flywheel, the energy generating module may simply carry a slip-ring, pantograph or other conventional device to transfer electrical energy to or from the flywheel, as may be desired and will be readily understood by those skilled in the art.

[0060] In some exemplary configurations, selected energy generating modules may also be provided with upper ends of mooring legs formed by cables and / or chains in the conventional manner of offshore floating structures. In this case, there may be three or more circumferentially arranged pairs of mooring legs to hold the flywheel in place and the associated energy generating module in a global position while allowing the flywheel to move freely vertically within a desired vertical range.

[0061] In alternative configurations, energy generating modules or integrated modules may not need to be provided with a pair of mooring legs. For example, they may be held in a global position by suitable module connectors, as will be readily appreciated by those skilled in the art.

[0062] Such as Figure 1The integrated module shown is preferably a multi-process module including an energy generation module and power management facilities. It may include additional facilities, including but not limited to electrolysis facilities, such as the production of hydrogen and oxygen. For example, it may also provide accommodation facilities.

[0063] It should be noted that in some configurations, the integrated module may be located on a fixed structure adjacent to the flywheel, in which case the energy generating module would be mounted separately on the flywheel, and the electrical energy generated thereby would be transmitted to the integrated module. For example, it may be transmitted via one or more catenary cables or other means. In the case of catenary cable transmission, these cables may first be suspended from the module connector before reaching the target integrated module at a nearby circumferential location.

[0064] Figure 2 An exemplary and preferred construction of a flywheel is shown. Figure 1 The deck width X taken along line AA is shown in an enlarged partial section.

[0065] As mentioned above, the opening 2 is provided to allow provision of an air cushion for supporting the flywheel. When used in open water, the air cushion will dampen the pitch and roll response of the flywheel to incident waves propagating beneath and through the flywheel, only partially damping to further mitigate incident wave forces.

[0066] As mentioned above, it is preferred that the flywheel has a honeycomb structure. By providing a honeycomb structure, material volume (and cost) can be reduced while still allowing mass to be varied by ballast. It should be noted that any wall or deck can be ballasted in any combination to maintain uniform mass distribution around the flywheel.

[0067] The energy storage capacity of the flywheel 1 can be increased by increasing its mass and thereby increasing its extreme second moment of inertia. For a honeycomb structure, its mass can be increased by pressurizing the cells 7 with water. This provides an economical solution for varying the mass of the flywheel, thereby managing its energy storage capacity and angular velocity of rotation as required.

[0068] Preferably (although not necessarily), as in the present configuration, each cell is bounded by radial and circumferential walls so as to minimize the effect of the free surface of any partially filled cell on the hydrostatic stability of the entire flywheel. In preferred operating practice, most of the ballasted cells will be filled to minimize free surface effects.

[0069] It is worth noting that, if possible, uniform air pressure across the entire flywheel structure will serve to reduce Figure 2 The bending moments developed in the cross-section shown allow a very economical thin-wall design in the deck structure.

[0070] If required, a ballast system may be provided to allow selective ballasting of the unit. The ballast system comprises a plurality of valves 8 and preferably also a pump 9. The ballast system allows the controlled introduction and discharge of water from the unit 7.

[0071] For illustrative purposes, Figure 2 A configuration with (shaded) ballasted cells and dry cells is shown.

[0072] In this exemplary configuration, the unit 7 is supplied by an inlet manifold 10 and discharged by a discharge manifold 11, which is controlled by a valve 8, which is preferably remotely actuated. The present invention need not be limited to this exemplary configuration. For example, an alternative configuration can omit the manifold. In a configuration comprising manifolds 10, 11, an inlet 12 and an outlet 13 are provided, which are connected to the inlet manifold 10 and the outlet manifold 11, respectively. The inlet 12 and the outlet 13 are preferably oriented so that the rotation of the flywheel contributes to the application of ballast and deballast. It is possible to implement the ballast system in this way without using a pump 9. However, as shown in the figure, one or more pumps are preferably provided.

[0073] The pump will effectively assist with ballasting, particularly when the inlet manifold is at a level above the inlet in use, or when the flywheel is not spinning fast enough to automatically prime the system.

[0074] In certain exemplary configurations, particularly when the pump is configured to function as both a pump and a turbine, the introduction of one or more pumps can further increase utility.

[0075] In a preferred configuration, the input electrical energy is converted into mechanical energy in the energy generation module, either in a manner as previously exemplified by the motorized bogie, or where the outer periphery of the flywheel acts as the rotor of an electric motor / generator, with the energy generation module forming the stator, so that the converted rotational mechanical energy is directly added to the flywheel at this interface, increasing its angular velocity. Alternatively, in cases where it is necessary to maintain a constant angular velocity, typically, in order to maintain the target tangential velocity at its set point, for example, additional ballast can be installed on the flywheel to increase the angular moment of inertia of the flywheel by a corresponding amount. The opposite is true when electrical energy is regenerated from stored rotational mechanical energy.

[0076] When the conversion of rotational kinetic energy stored at the flywheel into electrical energy is carried out, another preferred option is to allow flow under centrifugal pressure from the ballasted unit 7 through valve 8 into the exhaust manifold 11 and then through the pump 9 acting as a turbine, or through one or more separate turbines, to generate electrical energy.

[0077] In contrast, when electrical energy from an external source (e.g., a wind farm, etc.) is input to the flywheel 1 for conversion from electrical energy to rotational kinetic energy stored by the flywheel 1, a preferred option for such conversion is that the input electrical energy powers a pump 9 used as a jet pump to discharge high-energy water through an outlet, thereby generating a tangential force on the flywheel 1, which increases its angular velocity, thereby increasing the amount of rotational kinetic energy stored. The water ejected from the outlet can be drawn into the discharge manifold 11 from the ballasted unit 7 through the valve 8, thereby additionally reducing the second moment of inertia, helping to accelerate the rate at which the tangential velocity increases to the target value.

[0078] Alternatively, water ejected from outlet 13 may be drawn through discharge manifold 11 under centrifugal pressure and passed directly from inlet 12 through a portion of the manifold cross-connected to the discharge manifold (not shown) and then through pump 9 which acts as a turbine driven by input electrical energy to increase the tangential speed and store it as rotational mechanical energy.

[0079] It is noted that the above configuration may be achieved using separate pumps and turbines, which may be mounted in suitable manifolds to allow one or the other to function.

[0080] While a flywheel according to the principles discussed herein will exhibit a relatively flat performance curve, indicating that the "round trip" energy storage and recovery efficiency will be somewhat tolerant of practical angular velocities, it is expected that in any particular design there will be a target tangential velocity and corresponding angular velocity. By providing a ballast configuration, according to the exemplary configuration described above, or otherwise, the flywheel will provide the ability to: first, bear ballast when receiving electrical energy for conversion and storage as rotational kinetic energy; and second, release ballast in the opposite case of generating electrical energy from its rotational kinetic energy. This allows the total mass of the flywheel to vary, so that its extreme second order moment of inertia varies to compensate for the varying amount of stored energy, and a constant tangential velocity can be maintained, thereby maintaining maximum operating efficiency and further effectively flattening the performance curve.

[0081] like Figure 2 As shown in the example in, the flywheel 1 can optionally be provided with a drag member 14. The form of the drag member 14 does not need to be particularly limited. The drag member 14 may comprise a plate. The use of a drag member is particularly interesting when the flywheel is located in open water. Such drag members 14 may be mounted at regular points around the outer circumference of the flywheel 1. They are preferably mounted telescopically, wherein they can be opened as required, or stowed flush with the outer circumference of the flywheel 1 when not in use. For this purpose, they may be pivotally mounted. A person skilled in the art will readily appreciate a variety of suitable mounting configurations. Figure 3 In view A a side view of an exemplary traction member 14 is shown fully deployed and also showing the recess 15 into which it may be loaded.

[0082] As mentioned above, one function of the air cushion is to limit the surface friction between the flywheel 1 and the water by minimizing the wetted area. Some friction will remain as this helps to reduce the tangential velocity and to circulate the water in its vicinity by drawing it around the wetted surface to a certain extent. By providing the traction member 14, some of the kinetic energy of this circulating water can be recovered. The velocity profile of the circulating water will decrease with increasing radius away from the flywheel, but its effective planar size will continue to increase radially outwards as energy accumulates, thereby forming a vortex around the flywheel. This vortex is a very effective storage of rotational kinetic energy, and its natural decay is quite slow.

[0083] It is also noted that as the vortex absorbs energy from the flywheel 1 and increases in size, the tangential velocity of the vortex near the interface with the external wetted surface of the flywheel 1 also increases, thereby reducing the relative velocity between the vortex and the flywheel 1 and reducing the shear force between them, thereby self-limiting the energy loss into the vortex.

[0084] In this case, the traction member 14 can play two roles:

[0085] First, if it is necessary to stop the flywheel 1 as quickly as possible, for example for some unplanned maintenance, or for other reasons, the energy originally stored must be consumed. If this exceeds the ability of the power generation system to convert into electrical energy, or exceeds the transmission or consumption capacity of the energy output facility, the traction member 14 can be deployed so that the traction force experienced increases, thereby slowing down the rotation speed. This traction force will generate turbulence in the path of the traction member 14, in which energy is permanently lost in the form of heat. However, this traction force will also increase the size and kinetic energy of the vortex, and some of the lost energy will be stored in the vortex.

[0086] Secondly, when the stored energy is largely consumed due to long-term demand with little or no replenishment, a situation may arise where the surrounding vortex rotates faster than the flywheel 1. In this case, some of the flywheel stored energy can be effectively recovered by deploying the traction member 14 to increase the tangential traction of the vortex on the flywheel 1, i.e., the reverse process of the above process.

[0087] Figure 3 As shown above with particular reference to Figure 2 A side view of the inlet 12 and outlet 13 discussed. In the exemplary configuration depicted, the inlet 12 is provided with a bellmouth inlet configured to smooth the incoming flow. As will be readily appreciated by those skilled in the art, the inlet may be configured in other ways. As shown, the inlet 12 and outlet 13 are preferably housed in smooth pods to minimize drag. In some configurations, these pods may be retractable, wherein their retraction will leave a smooth circumferential surface for the flywheel to further limit drag when the pods are not in use.

[0088] The device is preferably configured so that the velocity of the jet stream passing through the outlet 13 can be varied. In some exemplary configurations, the outlet 13 can optionally be split into two or more telescopic sections of gradually increasing inner diameter, forming a draft tube, to decelerate the flow emerging from the outlet without excessive turbulence losses. Figure 3 An example comprising three such parts is shown. In alternative configurations this need not be the case. In particular, there may be alternative means for controlling the speed of the sprayed water.

[0089] As mentioned above, a flywheel according to the principles of the present invention will generally be designed to include an optimum tangential velocity V T 1. The flywheel 1 is preferably operated at or near its optimum performance point. In this case, the flow from the outlet 13 can be configured relative to the discharge velocity of the flywheel 1 so that it has a velocity close to zero relative to the adjacent water into which it is sprayed. Such a configuration will minimize turbulent losses. However, when the flywheel 1 is operated away from its optimum design point, it may be desirable to accelerate the angular velocity of rotation of the flywheel 1 to reduce or eliminate the velocity mismatch between the jet and the water in the vortex, where the jet can mix without undue losses.

[0090] We will now consider in more detail the use of Figure 3 An exemplary configuration for speed control.

[0091] When the flywheel has reached its tangential speed V T When the full design value is 1.5, it may be appropriate for the water ejected from the outlet 13 to have a high relative velocity relative to the surrounding water velocity. In this case, only the first upstream part of the cabin can be deployed, and the outlet diameter of the outlet will be the minimum diameter available.

[0092] At start-up, when the flywheel is still spinning slowly, the speed mismatch between the ejected water and the surrounding water is much smaller, and it is preferable to allow the ejected water to travel more slowly in the longer draft tube before entering the surrounding water to minimize energy losses. For example, here, all three sections can be deployed (as Figure 3 ), to minimize turbulence losses by more closely matching the velocity of the jetting water to that of the surrounding water.

[0093] There is also a situation where, for medium speeds, only two sections are suitable for expansion.

[0094] It should be noted that, as described above, alternative means for velocity control of the sprayed water may be implemented and, as will be readily appreciated by those skilled in the art, the control described above may be achieved alternatively.

[0095] Figure 2The seabed 17 is shown. If the water is shallow, bottom clearance will be limited and induced eddies may cause erosion. This can be avoided by proper rock dumping of the area prior to installation.

[0096] It should be noted that in any annular structure of the flywheel 1, including the spaced-apart overhanging circumferential walls 3, 4, these walls may be substantially identical to one another or may be different from one another. These walls may be considered to include an inner circumferential wall 4 and an outer circumferential wall 3. Both the inner circumferential wall and the outer circumferential wall may include cells 7 to allow them to be ballasted, only one of the inner circumferential wall and the outer circumferential wall may include cells, or neither circumferential wall may include cells. The inner circumferential wall and the outer circumferential wall may have the same thickness or may have different thicknesses from one another. Different combinations of these features may be provided in the exemplary configuration.

[0097] Figure 4 An exemplary configuration is shown in which the thickness of the outer circumferential wall 3 is greater than the thickness of the inner circumferential wall 4. According to the above discussion, both walls have the ability to be ballasted, although this is not a requirement.

[0098] The outer circumferential wall 3 is made thicker because it is at the largest overall diameter of the flywheel, and its underwater displacement is the main factor in maintaining the hydrostatic roll and pitch stability of the flywheel. The inner circumferential wall 4 is a secondary factor in hydrostatic stability, and its thickness can be selected to provide mainly sufficient structural strength, wherein sufficient hydrostatic stability is already more effectively provided by the selected thickness of the outer circumferential wall.

[0099] As a separate consideration, and equally applicable to all annular configurations of the flywheel, the thickness and configuration of the deck 5 may vary. The thickness may be set to maximize its volume, and thereby maximize the mass of the ballast water in its cells 7, to effectively increase the energy storage capacity. It is worth noting that, as an advantage of the air cushion, the weight of the deck and any ballast is supported uniformly. This allows a relatively light structure to be provided. The uniform support of the air cushion minimizes bending moment stresses. The use of the air cushion results in a reduction in the overall cost of the flywheel compared to a structure without such uniform support.

[0100] Although not limited to Figure 4 The above features of the flywheel 1 shown, but Figure 4 The configuration also exemplarily discloses an output system 6, which will now be discussed further. It should be noted that this configuration may be incorporated into alternative arrangements including flywheels of alternative constructions, such as those discussed elsewhere in this application.

[0101] The output system 6 comprises an integrated module in which a power management system is arranged. For example, this may include conventional cables for power transmission, such as but not limited to high voltage DC cables. It may additionally include pipes, such as but not limited to steel pipes, for outputting hydrogen when hydrogen is optionally generated from electrical energy in the integrated module.

[0102] As shown, this type of energy output system is suitable for output from a fixed structure to which the cable can be fixed. For example, the cable can be fixed by pulling it upward through a J-tube, or attached to a support or leg of the fixed structure after installation. If a pipeline is to be provided, a pipeline riser can be installed on the fixed structure for subsequent seabed connection to the pipeline. The pipeline can also (if the pipeline diameter is small) be pulled upward through the J-tube.

[0103] Figure 5 A discloses a configuration where no fixed structure is present. This configuration may be implemented, for example, when the water depth is sufficient to provide an energy output system in the form of a flexible cable or flexible pipe 19 with sufficient structural integrity to be suspended in a catenary from the flywheel to the seabed.

[0104] Figure 5 B shows Figure 4 Detail B in FIG. Note that in this exemplary configuration the integrated module is provided with a helicopter deck for service personnel to enter. The provision of a helicopter deck is entirely optional.

[0105] Figure 6 Another alternative is disclosed in which the integrated module is located on a semi-submersible platform 20, which is moored to the energy generation module. This configuration may be useful in deep water environments. In this configuration, it is preferred to provide a support device for the semi-submersible platform. In the exemplary configuration described, an articulated tether frame 21 is provided. This is preferably configured to allow the semi-submersible platform to freely pitch, roll and heave. It can also be arranged to provide access to the flywheel 1 by service personnel and equipment. Note that an optional horizontal configuration of the energy generation module is also shown, which can be implemented in various alternative configurations discussed herein.

[0106] Figure 7Another exemplary configuration is disclosed which includes a flywheel 1 characterized by a central inverted cabin 23. Any of the above energy systems may be implemented, and the configuration is not limited in this respect. The central cabin 23 provides an alternative means of applying ballast. In this configuration, it is preferred that the cabin 23 is in fluid communication with the units 7 of the flywheel structure via appropriate radially extending fluid transport members 24. In the present configuration, these include conduits. The conduits may be spoke-shaped. Liquid entering the cabin 23 will flow radially outward through the conduits under centrifugal pressure. As described above, pressure relief may be provided by a suitable outlet or otherwise. As with the previously described configurations, a pump may or may not be provided, which may also act as a turbine or be provided in addition to a separate turbine.

[0107] Generally speaking, the pump / turbine can be omitted from any arrangement to increase the ballast water exit velocity. This arrangement provides simplified auxiliary machinery fit and reduced surface friction.

[0108] Figure 8 An exemplary arrangement is shown provided with mooring / support legs 25. As shown, such mooring / support legs 25 may be connected to a central swivel 27. Regardless, they are preferably deployed to the seabed substantially within the planar footprint of the flywheel 1 to provide a compact configuration.

[0109] Figure 8 Also disclosed is an onboard module 26 which may be mounted as desired on any of the above devices, but particularly on versions with onboard energy generation. The onboard module 26 may house various auxiliary mechanical devices and utilities as desired, which in alternative configurations may otherwise be housed in an integrated module, or otherwise located / housed.

[0110] Such conventional auxiliary machinery may include, but is not limited to, any one or more of the following:

[0111] o Air compressors to control air cushion pressure and volume, replenishing air lost from beneath the structure during extreme weather or absorbed into seawater.

[0112] o Voltage control, allowing the input of electrical energy from multiple sources to be combined and exported economically to the onshore grid.

[0113] o Emergency power generation.

[0114] o Fire main pump.

[0115] o Temporary or permanent living quarters. Any such manned space may be equipped with a floor that is tilted toward the flywheel center axis. The tilt angle may be set so that the line of action of the combined force of gravity and centripetal force simulates the line of action of normal gravity, so that personnel can move at a target peripheral speed V Tand move around unhindered.

[0116] oBallast and / or deballast pumps.

[0117] oCommunications and AI-assisted instrumentation and control systems.

[0118] o Electrolysis unit to produce hydrogen and compress and process it for export. If required,

[0119] The oxygen produced simultaneously can also be dried, pressurized and exported.

[0120] In a configuration including a rotary joint 27, consistent with the above discussion, the rotary joint 27 can provide energy output via a cable and / or a flexible hydrogen pipeline. It can also be configured to provide electrical energy input from an external source for storage as rotational kinetic energy.

[0121] In a preferred arrangement, the swivel comprises a buoyancy tank 30. The buoyancy tank 30 will preferably be configured to be partially submerged in use.

[0122] The buoyancy tank 30 may help support the weight of the components of the flywheel 1. When provided, the buoyancy tank 30 may help support the weight of one or more or all of the following components: the swivel, the helicopter deck 31, the spoke elements, which may be fluid transport elements as described above, or may alternatively be purely structural elements as in the configuration shown.

[0123] When mooring / support legs 25 are provided, the pontoon 30 may additionally or alternatively configure the mooring / support legs 25 so that their lines of action intersect the swivel joints 27 at locations where they intersect the spoke elements. Such a configuration will minimize any significant bending moments on the spoke elements due to lateral forces restrained by the support / mooring legs.

[0124] As discussed, the flywheel 1 may optionally be provided with a helicopter deck 31. When provided, the helicopter deck may be mounted in the center of the flywheel. In a configuration with spoke elements, these spoke elements may provide support for the helicopter deck 31 and further provide a configuration for access to the facility. For example, in a closed circular configuration of the flywheel, such as Fig.10 A, the helicopter deck can simply be marked on the deck. In a sufficiently large flywheel, as is contemplated within the scope of the present disclosure, there will be sufficient clear passage to land a helicopter in its center. Furthermore, in the center position, the rotation speed will be low enough so as not to impede the operation of the helicopter while the flywheel is in operation. For example, a large flywheel may take several minutes to complete one rotation.

[0125] Fig. 9 Shows something like Figure 8 configuration, i.e. including the rotary joint 27, but also including, for example, Figure 7 The central inverted cabin 23 in question. The swivel joint 27 and cabin 23 can be combined into a single unit. Figure 7 The spoke elements preferably include ducts for ballast purposes. Figure 8 The configuration provides mooring / support legs 25.

[0126] As described above, and as will be readily appreciated by those skilled in the art, different features / feature combinations from the above-described different configurations may be combined / changed. In particular, the disclosure of a particular feature in conjunction with other features of a particular configuration does not tie those features together. These embodiments are non-limiting and are for illustrative purposes only.

[0127] Fig.10 A. Fig.10 B and Fig.10 C shows three different exemplary configurations of flywheel structures that may be implemented in configurations that include any of the features discussed above with respect to the described configurations.

[0128] Fig.10 A shows a closed circular configuration. This is in contrast to the toroidal configuration of the flywheel discussed above. The closed configuration will produce lower surface friction compared to the toroidal configuration because it only has one wetted surface to penetrate.

[0129] Fig.10 B shows a ring configuration. If it has Fig.10 A closed circular configuration of the same plan area and mass will have a greater energy storage capacity because its mass is concentrated at its perimeter.

[0130] Fig.10 C shows a layered ring configuration. If this Fig.10 Configuration B has the same plan dimensions, but the mass is Fig.10 If the current is twice that of B, it will have twice the energy storage capacity.

[0131] Note, however, that the target tangential velocity V for any flywheel configuration is T can be chosen to have a similar maximum value that limits the surface friction between the outer circumference and the surrounding water to a reasonable level. For example, the upper limit of the tangential velocity can be set to 80 km / hr. For example, if Fig.10 The closed circular structure shown in A and Fig.10 The layered annular structure shown in C has the same tangential velocity V T , then the inherent energy storage advantage of the latter is mitigated by its lower angular velocity of rotation due to its larger diameter (assuming this is the case).

[0132] Presentation Fig.10 A to Fig.10C is intended to help illustrate the design principle according to the present disclosure and is not limiting.

[0133] Fig.11 An exemplary, non-limiting complete cross-section of a flywheel is shown. Although the flywheel is a layered annular structure, it need not be so limited. It can be annular and formed according to any of the above configurations. It can also form a closed circular structure.

[0134] Fig.11 A shows an onshore configuration option in which the lower ends of the inner and outer circumferences of the flywheel are immersed in separate grooves 33, 34 which are completely circular in plan view.

[0135] Fig.11 B shows another land-based configuration option, where the flywheel tip is immersed in a single tank 35.

[0136] The choice between these two options is a matter of economy. For example, a separate tank may require less on-site excavation than a single tank. However, an airtight closure may be required on the exposed ground between two concentric tanks of an installation including a separate tank to economically maintain the target head required for the air cushion. As will be readily appreciated by those skilled in the art, the tanks may be constructed in any suitable conventional manner.

[0137] Note that unlike an offshore flywheel, because the volume of water in an onshore configuration may be a separate volume, it is possible and desirable to add friction-reducing chemicals, such as but not limited to long chain polymers, to the water to reduce drag on the flywheel or to increase the target tangential velocity V. T , thus providing greater energy storage capacity.

[0138] Note also that the economy of the site can be improved by selecting the height of the flywheel so that excavation is performed beneath the flywheel to provide ground clearance which provides an amount of excavated material sufficient to construct an embankment supporting the external separation tank.

[0139] A plurality of energy generating modules may be provided. Three or more equally spaced energy generating modules may be provided, which are held in place circumferentially and radially by suitable support structures. The vertical height of the energy generating module may be controlled by the position of the flywheel. The support structure may also be configured to hold the flywheel in a planar position.

[0140] While the exemplary onshore configuration is annular, it may also include a closed circular structure.

[0141] It is worth noting that in the onshore case, the comparative economics metrics between closed loop, loop, and tiered loop configurations are different from those governing the choice of configuration offshore for a number of reasons:

[0142] o The necessity to attenuate the effects of incident wave energy on the flywheel by having a minimum overall diameter of approximately 1500 meters no longer applies. Smaller diameters may be sufficient to meet site requirements for onshore flywheels.

[0143] oOnly the outermost single slot is required.

[0144] oWhen the air cushion extends over the entire planar area of ​​the flywheel, the shaded area can be much larger.

[0145] For offshore installations, there are still other systems and considerations, and it should be noted that various aspects of the disclosed apparatus for offshore installations can be incorporated into onshore installations, as will be readily appreciated by those skilled in the art. Although briefly mentioned, the apparatus has thus far been discussed primarily with respect to the storage of externally generated energy. Figures 12 to 20 , the device will be considered for use in generating electricity. The device can be configured to generate power from wind, wherein the wind provides rotational kinetic energy to a flywheel and is stored without any conversion.

[0146] To this end, a flywheel 1 according to any configuration described herein may be provided with a plurality of sails 37 attached thereto. The sails may be mounted on the deck 5 of the flywheel, thereby effectively forming a large cross-flow wind turbine. They may be mounted in other ways. As will be appreciated by those skilled in the art, any such sail may take a variety of configurations. Some non-limiting exemplary sail configurations are discussed below.

[0147] Fig.12 A shows an exemplary configuration with a sail. Preferably, this configuration includes a continuously variable sail geometry. In this exemplary configuration, a single flexible sail is provided that can be twisted in small increments above the water surface to an optimal angle of attack relative to the prevailing wind direction at any height.

[0148] This configuration accurately takes into account the continuously changing wind speed and direction at different heights. This variation occurs naturally but is also a feature of the crossflow turbine airflow. In this exemplary configuration, there is a vertical mast 38, which is preferably rigid. Considering the wind loads from the sails that the mast is subjected to, the mast can be divided into a plurality of segments. The number of segments can be determined based on the maximum allowable bending moment and axial Euler buckling capacity of each mast segment.

[0149] Fig.12A shows a configuration including two such segments, it being understood that there may be more or fewer segments in any configuration provided in accordance with the present principles consistent with the above discussion. The vertical length of each such segment is preferably increased by providing a universal joint where the segment is connected to the flywheel or another segment, which will substantially eliminate bending moments at these intersections. Each segment may be constrained circumferentially and radially inwardly in a plane by rigging 39, which may preferably be diagonal, and rigging 40 may be substantially horizontal.

[0150] Suitable instrumentation / sensing means may be provided for determining the optimum angle of attack and / or airfoil shape for the continuous variation of the geometry of the continuously variable sail at each height increment, and / or the stress levels at the mast segment length increment. As will be readily appreciated by those skilled in the art, AI systems comparable to those used in advanced aviation practice may be employed.

[0151] Fig.12 B shows the Fig.12 A Similar sail configuration. Fig.12 The configuration of B also includes multiple sail segments. However, in this configuration, multiple rigid sail segments are deployed. Each segment can be configured, for example, in the manner of a conventional aircraft wing structure. By providing rigid sail segments, a separate rigid vertical mast is not required, although a configuration with such a mast is possible. Each individual sail segment can be rotated independently to align it with the average wind speed and direction over the entire length, thereby providing the best available direction and lift amount on that segment. The greater the number of segments, the more accurately the sail segment will be able to track the prevailing wind speed and direction at each altitude increment. Fig.12 B shows four such segments by way of example. However, it is not limited thereto. More or fewer segments may be provided. Fig.12 As shown in Figure A, rigging 39, 40 is used to support the sail structure. Increasing the number of sail segments will increase the rigging required, given the number of segments to be implemented. As the rigging increases, the drag will also increase. It is desirable to achieve an effective balance.

[0152] as Fig.12 As with the configuration of A, suitable instrumentation / sensing arrangements may be provided for input to the sail control system. Again an AI system may be employed.

[0153] Fig.13 Shows Fig.12 A configuration plan. It should be noted that Fig.13Two optional exemplary rigging options are shown in the middle section, respectively labeled A and B. It should be understood that these are optional, wherein only one of these rigging configurations is implemented for each provided mast. According to configuration A, each strand of rigging 39 extends to the center of the flywheel. In configuration B, each strand of rigging 39 extends to be supported radially outward from the center of the flywheel. Suitable support structure can be provided for this purpose. Of course, in configurations where the flywheel is not annular, the top deck will be available for mounting the ends of the rigging brackets. The comparative economics of cost and drag in actual operation may determine the preferred rigging configuration for any given design. In addition, those skilled in the art will readily understand alternative configurations to A and B. As described above, as those skilled in the art will understand, these configurations are purely exemplary and can be changed or modified in many ways.

[0154] Note that facilities may be provided so that the length of the rigging cables may be adjusted to safely lay the entire sail and rigging arrangement flat on the deck of the flywheel radially or circumferentially as required for maintenance and subsequent return to the operating configuration shown.

[0155] Fig.14 is to describe the geometry of the continuously variable sail (e.g. Fig.12 A) and rigid sail segments (as Fig.12 B) can be reversed and also adopt a symmetrical shape relative to the average wind direction as shown by the arrow.

[0156] Regardless of their specific configuration, the sail segments can be configured to adopt the airfoil form shown, whereby the sail segments in the distal and proximal half-sectors of the flywheel shape contribute to clockwise rotation, as viewed from the wind direction. The sail segments at the junction of the nearer and farer half-sectors are preferably symmetrical transitional shapes as shown. The left end sail segment is preferably at right angles to the wind direction to contribute to clockwise rotation. The right end sail segment preferably has a symmetrical transitional shape viewed in the wind direction to directly face the wind direction, thereby minimizing its drag.

[0157] Note that the orientation and shape of each airfoil section is preferably not simply maximized by the control system to give the maximum lateral lift, where the parameter controlling the tangential velocity may be the moment of the lateral lift about the central vertical axis of rotation. Therefore, the control system preferably continuously calculates and maximizes the product of the lift about the central axis and the moment arm about the central axis, and adjusts the airfoil shape and orientation accordingly. It can be seen from this that the control system can be configured to set an angle of attack that produces less than the maximum lift but in the direction of the larger moment arm.

[0158] Now refer to Figures 15 to 18, shows an exemplary, non-limiting configuration of the mechanical components of a control system for orienting a sail in its proper shape and orientation. The disclosed system may be implemented in terms of continuously variable sail geometry or rigid sail segments. It is described in the context of a rigid vertical mast, but may be suitably adapted to configurations that omit the mast, such as, but not limited to, configurations that include rigid sail segments, as described above. As will be readily appreciated by those skilled in the art, many alternative mechanical configurations will be possible.

[0159] Fig.15 A discloses a short aerofoil shape control cylinder 41 around a rigid vertical mast 38. As shown, the aerofoil shape control cylinder 41 carries a spherical bearing 42 and can be rotated in either direction relative to the rigid vertical mast 38 by an actuator 43 mounted in a bushing of the rigid vertical mast 38 so as to drive a gear 44 meshing with an opposing rack. The aerofoil shape control cylinder 41 is held concentric with and supported by two or more idler gears 45. Hydraulic supply and return pipes 46 provide power to all elements of the entire system under the control of signals received from the cable. Status feedback signals are also transmitted back through the cable. Preferably, computerized management of all control system elements is achieved using AI, which is one of the facilities that can be appropriately accommodated in the integrated module or onboard module 26.

[0160] Fig.15 B discloses providing a concentric shorter sail orientation cylinder 47 around the airfoil shape control cylinder. The sail orientation cylinder is rotatable in either direction by an actuator mounted in a rigid vertical mast and is supported and held concentric by a plurality, preferably at least three, idler wheels.

[0161] Fig.16 An exemplary configuration is disclosed in which a blade orientation cylinder 47 carries a blade profile stretcher 48. An airfoil nose profiler 49 is mounted on a support arm 50 containing a telescoping portion 50a. The support arm is mounted on a trunnion carried on the sail orientation cylinder and slides through a bushing carried in a spherical bearing 42.

[0162] Fig.17 Shows Fig.16 Section "AA" in FIG. 1 and shown in elevation Fig.16 The same components disclosed in the plan view.

[0163] Note that Figures 15 to 17The complete assembly disclosed in can be installed in places where the height increases frequently, where continuously variable sail geometry is deployed. In contrast, in the case of using rigid sail segments, a complete assembly can be installed, for example, at the bottom of each rigid sail segment.

[0164] Fig.18 A. Fig.18 B and Fig.18 C exemplarily discloses the above Fig.14 The discussion of the consistent details of three possible key shapes of the airfoil section.

[0165] In a preferred exemplary configuration, the leading edge of the airfoil section may be made of a strong fabric attached on the upper and lower surfaces of the airfoil section to a sail-shaped profile stretcher, which itself is made of a thin flexible material such as, but not limited to, sheet steel, aluminum, plastic, or a composite material. The airfoil section may also include, for example, Fig.18 The airfoil stretcher shown extends back to the trailing edge and vertically over the entire surface of the continuously variable wing geometry or rigid wing section. Optionally, the rear part of the airfoil section can also be made of solid fabric, in which case a similar mechanism can be additionally installed, e.g. Fig.16 and Fig.17 A mechanism is shown for changing the front body of an aerofoil section, thereby changing the shape of the rear body of the aerofoil section.

[0166] An alternative exemplary preferred solution comprises a sail-shaped profile tensioner which continues rearwardly to the trailing edge in sections and is mounted on an actuated hinged portion of the extreme end portion in a manner similar to a flap on an aircraft wing shown in dashed lines.

[0167] In order to rotate at any given height Fig.14 To adjust any sail in the plane shown, but without changing the shape of its airfoil, the actuator and actuators can be operated in unison so that there is no relative rotation between them. To change the shape of the airfoil section, actuator 43 or actuator 53 is operated to produce relative rotation between the airfoil shape control cylinder and the sail orientation cylinder. This relative rotation is as shown in FIG. Fig.16 As shown, the airfoil head shape profiler is moved in either direction. To avoid wear on the flexible fabric forming the leading edge of the airfoil section, the airfoil nose shape profile can be configured to rotate clockwise or counterclockwise. The flexible fabric can be accommodated by a telescopic portion mounted in the support arm.

[0168] If the control system so requires, the actuated hinged portions may be simultaneously deployed to further change the shape of the airfoil portion.

[0169] Fig.19Some exemplary, non-limiting measures are disclosed that may be used to improve the damage stability of a flywheel according to any of the above configurations. It should be noted that Fig.19 A cross section of two different parts of an annular flywheel is shown in elevation.

[0170] Fig.19 For the first time, the substantially superior inherent stability to damage of any flywheel provided by the honeycomb structure forming a "double shell" is shown. Two separating surfaces are damaged to allow air to escape. Stability can be further enhanced by extending selected radial cell walls 56 and circumferential cell walls 54 below the deck level but above the lower boundary of the air cushion, forming open cell circumferential walls and open cell radial walls. Except in the case of one or more cells that have been opened to the atmosphere for any reason, in the event that the air cushion is released into the atmosphere, the freeboard of the flywheel will decrease as its position in the water is lowered until the open cell circumferential walls and open cell radial walls enter the water surface and the air they capture is compressed to the point of buoyancy equilibrium. Multiple air cushions in many complete cells will be designed to provide sufficient wave action compliance to maintain sufficient (albeit reduced) freeboard to mitigate destructive bending moments long enough to restore the damaged flywheel to shallow water and make necessary repairs.

[0171] When damaged, further integrity may be provided by extending the wall of one or more circumferential cells 55 downwardly through the air cushion into the water below. This will isolate the annular ring or reduce the loss of air cushion of an annular ring accidentally opened to the atmosphere and limit the subsequent freeboard reduction in the event of damage. However, there are increased skin friction losses during operation.

[0172] Fig.19 An inverted triangle symbol is also used to represent the water level on all figures, and the water level difference H between the free water surface and the air bearing surface is shown.

[0173] Fig. 20 Two conceptual flywheels are shown in plan view, a closed circular configuration and a toroidal configuration. Fig.19 Exemplary, non-limiting open cell circumferential walls and open cell radial walls are discussed.

[0174] In the context of the above description, many further configurations can be envisaged. Figure 21 to Figure 23 Two preferred but non-limiting examples are discussed. It should be noted that aspects of these configurations can be combined with aspects of any of the above configurations. The examples shown are not limiting. For example, Fig.21 and Fig. 22The flywheel configuration of can be used to replace the optional flywheel structure in any of the above-mentioned configurations, and / or any features of any of these flywheels can be introduced into a flywheel according to the configuration discussed herein. In addition, with reference to Figures 12 to 20 Any of the power generation devices discussed may be implemented with a flywheel configured according to the following discussion.

[0175] Fig.21 and Fig. 22 A closed flywheel configuration is shown in front view and plan view, respectively. The flywheel 1 has an annular structure. However, the open center of the ring is closed by a cover 60. There is no particular limitation on the form of the cover. In the configuration exemplarily described, it takes the form of a lightweight airtight disk. With the center of the ring closed, a single circumferential wall 3 can be provided. This is in contrast to the annular structure described previously. However, it should be noted that a cover such as that discussed here can be used with any of the annular flywheels described above, or with any other form of annular flywheel including a pair of circumferential walls 3, 4. It is preferred to use a single subordinate circumferential wall 3 because it helps to reduce the surface friction resistance from the water.

[0176] The cover 60 may be honeycomb-shaped. This allows for a rigid, lightweight structure. In addition, the honeycomb cover may be ballasted, consistent with the discussion above regarding ballasting. A ballasted cover increases energy storage capacity, and may increase the deadweight of the cover to more closely balance the air pressure in the air cushion, subjecting the cover to relatively light pressure in operation. Alternative structures for the cover include, but are not limited to, a lightweight frame formed of steel or other material, enclosed in an airtight shell of steel, concrete, glass reinforced plastic, airtight fabric, or other suitable material.

[0177] Using a closed cover configuration of the annular flywheel in this manner can significantly reduce the air cushion thickness, thereby minimizing the associated wall depth and its wetted surface area.

[0178] The associated circumferential wall can be stepped at a considerable distance from the outer circumference of the ring, i.e. the circumferential wall can be shifted radially inwards from the outer circumference of the flywheel. This is advantageous because Fig. 22 Its function is to reduce its circumferential length, thereby reducing skin friction drag, while maintaining sufficient hydrostatic stability. However, in alternative configurations, the circumferential wall may be provided at the periphery. The ring and central disc are preferably configured to remain above the water surface at a distance sufficient to reduce wave impact.

[0179] Fig.23 Shows Fig.12 A third preferred example C of the rigging arrangement in the middle. This configuration corresponds to the observation that in practice the spacing between the masts may be shorter than Fig.13As a result, the rigging of each mast will overlap with the rigging of several adjacent masts, forming a group of cables and possibly a wake shadow on the sails, which may limit their aerodynamic performance to some extent. Fig.23 As shown, by arranging the masts in rows of different radii and supporting them circumferentially and laterally with horizontal rigging, the number of diagonal rigging legs can be significantly reduced. Overall, the corresponding increase in horizontal rigging is much smaller than the reduction in diagonal rigging, thereby saving traction and cost. As will be readily appreciated by those skilled in the art, many alternative mast and / or rigging configurations are also possible.

[0180] In addition, Fig.23 In the configuration, the horizontal rigging casts a wake shadow, forming a horizontal disk at the level of the joint between vertically adjacent sails, which hardly disrupts the airflow profile over the sails, thus improving performance. Since a complete horizontal rigging pattern lies in the common turbulent wake to a greater extent than a diagonal rigging, the cables at the level of each horizontal rigging will also produce less drag per unit length than a diagonal rigging.

[0181] The masts are shown stepped from the outer circumference of the ring at a distance W. The distance W is chosen to be large enough to provide a reasonable geometry for the diagonal rigging. Further increasing W reduces the number of masts that can be installed and reduces the lever arm of the lift of the sail around the vertical axis of the flywheel. As will be appreciated by those skilled in the art, the distance W will be appropriately balanced depending on the specific implementation.

[0182] Reference Fig.24 , shows a partial cross-sectional view of a configuration of an apparatus including an optional fluid seal, which is particularly suitable for use in an onshore configuration. The fluid seal comprises a segmented labyrinth. In this configuration, the labyrinth is formed by a plurality of interlocking units, each unit being formed by a slave wall 70 depending from the flywheel 1 and a facing wall 71 protruding opposite the slave wall 70. In the illustrated structure there are four interlocking units. It will be appreciated that more or fewer interlocking units may be provided in alternative configurations. As shown in FIG. Fig.24 As shown, each interlocking unit generates a head difference K for water or other fluid F trapped between the slave wall 70 and the facing wall 71. The accumulated head difference is equal to the pressure head in the air cushion. Fig.24There are four units and the air cushion pressure head is equal to 4K. The subordinate wall 70 and the facing wall 71 extend circumferentially. As will be readily appreciated by those skilled in the art, there are no particular limitations on the materials or forms of the subordinate wall 70 and the facing wall 71. Although the subordinate wall 70 is shown hanging from the circumferential wall 3 of the flywheel 1, in an alternative configuration, the circumferential wall 3 may be omitted and the subordinate wall 70 directly attached to the underside 82 of the deck 5. The facing wall 71 may be connected to a suitable base 72, which may be concrete or other material. The fluid F in the labyrinth seal traps the gas in the opening 2 to define an air cushion. The flywheel 1 may incorporate any of the features of the above-described flywheels in any combination. In a preferred example, the flywheel may be annular with a cover, as described with reference to Fig.21 The flywheel 1 discussed here is in the form of a flywheel 1. Of course, it can also be formed in other ways.

[0183] Fig.24 Also shown are optional fluid injection ports, indicated by arrows 80, which may be selectively positioned to inject fluid into all or selected cells of the sealed labyrinth at appropriate points about the perimeter of the labyrinth to provide desired operational functions, including but not limited to the following:

[0184] Maintaining the optimum head difference K in each cell by pumping water into or draining water from the selected labyrinth cells.

[0185] Maintain an optimum head difference K in each unit by pumping compressed air into or releasing compressed air from the selected labyrinth seal chambers.

[0186] · Excess hot water generated by fluid friction is drained from the selected labyrinth unit and replaced with cold water.

[0187] Inject fluid drag reducing chemicals into the water of selected labyrinth cells.

[0188] In alternative configurations, the fluid injection port 80 may be omitted.

[0189] Fig.24 Also shown is an optional magnetic levitation ("MAGLEV") unit 81, which, as will be appreciated by those skilled in the art, can provide desired operational functions, including but not limited to the following functions:

[0190] Converts electrical energy input into stored mechanical energy through induced tangential torque.

[0191] ● Conversely, the stored rotational mechanical energy is converted into electrical output through the induced tangential torque.

[0192] Provides additional vertical support to supplement the support provided by the air cushion.

[0193] ● Maintain the vertical and horizontal position of the entire flywheel assembly within a tight enough range to facilitate construction within practical tolerances.

[0194] ● Limit any tendency of the entire flywheel assembly to resonate.

[0195] It should be understood that the illustrated configuration of the magnetic levitation unit 81 is purely schematic and should not be considered limiting. As will be readily appreciated by those skilled in the art, the magnetic levitation unit 81 may take any suitable form. The inverted "V" shape shown for the interface between the rotating top and the fixed lower portion is merely one of many optional configurations for providing vertical and horizontal support and alignment. Other such optional configurations include, but are not limited to, separate vertical and horizontal magnetic levitation units, or a configuration in which one such separate unit is a magnetic levitation unit and the other is a conventional mechanical configuration, a diagonal interface forming a frustum of a large cone or inverted cone around the entire periphery of the magnetic levitation unit 81, an upright "V" shape, a "W" or an "M" shape.

[0196] It should be understood that the magnetic levitation unit 81 may be omitted, or, further, may be integrated into an alternative configuration that omits the labyrinth seal, as will be understood by those skilled in the art.

[0197] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. These terms should not be interpreted as excluding the presence of other features, steps or components.

[0198] The features disclosed in the preceding description or in the following claims or in the accompanying drawings, expressed in their specific form or as means for performing the disclosed functions or as methods or processes for obtaining the disclosed results, may, as appropriate, be used alone or in any combination of these features to realize the invention in its different forms.

[0199] Although certain exemplary embodiments of the present invention have been described, the scope of the appended claims is not intended to be limited to only these embodiments. The claims should be interpreted literally, objectively, and / or include equivalents.

Claims

1. A power generation and / or energy storage device, comprising a buoyant flywheel, wherein: The flywheel is configured to contact a liquid to rotate about a vertical axis when in use, and the underside of the flywheel includes a circumferentially extending opening, wherein, in use, gas is trapped in the opening by the surface of the liquid to define an air cushion for supporting the flywheel, wherein the flywheel has a honeycomb structure composed of a plurality of cells and is provided with a ballast system, the ballast system including one or more valves, and the ballast system is configured to control the introduction and discharge of liquid from the cells.

2. The device according to claim 1, wherein: The circumferential opening extends substantially continuously around the entire circumference of the flywheel.

3. The device according to claim 1 or 2, wherein: The flywheel is substantially annular.

4. The device according to claim 3, wherein: The device includes a cover that is airtight and closes the center of the annular flywheel.

5. The device according to claim 4, wherein the cover comprises a disc which can be honeycomb, or a frame enclosed by a shell, the frame comprising steel, concrete, fiberglass or airtight fabric.

6. A device according to claim 4 or 5, wherein the cover closes the opening.

7. The device according to claim 1, wherein: The flywheel comprises a pair of spaced apart circumferential walls depending from the flywheel in use, wherein the opening is provided between the walls.

8. The device of claim 7, wherein one of the circumferential walls is an outer circumferential wall.

9. The device according to claim 1, wherein: The flywheel comprises a single circumferential wall depending from the flywheel in use, wherein the opening is provided by the circumferential wall.

10. The device according to claim 9, wherein: The circumferential wall is disposed at or spaced radially inwardly from the periphery of the flywheel.

11. The device according to claim 7, wherein: The circumferential wall penetrates the surface of the liquid in use.

12. The device according to claim 7, wherein: The circumferential wall depends substantially vertically in use.

13. The device according to any one of claims 7 to 12, wherein: The opening is fully or partially closed by the circumferential wall and a deck to which the circumferential wall is attached, wherein the deck is substantially parallel to the surface of the liquid in use.

14. The device according to claim 13, wherein: The device comprises a cover which is airtight and closes the center of a toroidal flywheel; wherein one or more or all of the deck, the circumferential wall and the cover have a honeycomb structure.

15. The apparatus of claim 1, wherein the ballast system further comprises a pump for pumping the liquid into the unit and / or for pumping water out of the unit.

16. The apparatus of claim 1, comprising one or more compressors for supplying air to the opening.

17. The apparatus of claim 1, comprising one or more sails mounted to the flywheel.

18. The device according to claim 17, wherein: The sail extends substantially around the entire circumference of the flywheel.

19. The device according to claim 17 or 18, wherein: The sail may be rigid or flexible.

20. The device according to claim 17, wherein: A control system is provided for varying the orientation of the sail relative to the wind direction as the flywheel rotates.

21. The device according to claim 17, wherein: The sails are mounted to masts which are either self-supporting or supported by supports extending between the masts, wherein the supports may include rigging and may be configured to allow the sails and rigging to lie flat.

22. The device according to claim 17, wherein: Two or more radially spaced circumferentially extending arrays of sails are provided.

23. The device according to claim 1, wherein The flywheel has a diameter of 1500 meters or more.

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