Patent Application
20240035435
Not Applicable
Not Applicable.
The present disclosure is related to generating energy, e.g., electrical energy using a piston moved within a tube by the energy of buoyancy and gravity. The disclosure also relates to storing energy from other sources, where the stored energy can be exported when the other sources are not delivering energy.
There are a number of energy generating technologies available that produce energy only intermittently, as for example wind turbines creating electric energy when there is sufficient wind, solar panels creating electrical energy when there is sufficient daylight and wave action creating electric energy when there are sufficient waves, among other intermittent source. All intermittent sources are inactive if there is no primary energy source to drive or operate the intermittent source, as for example no or insufficient waves, nighttime or still air. During a substantial part of their operating time, intermittent sources produce excess energy that may be wasted, instead of being stored for later use because of insufficient energy storage capacity. Well-known electric storage includes electrochemical storage such as batteries. However, it is clear to the industry that other energy storage methods are also required for use with intermittent sources, and if such storage methods could also themselves generate electric energy, then there are better commercial opportunities for such storage devices.
One aspect of the present disclosure is an energy generating and storage system. The system comprises a piston defining an enclosed volume. The piston has an inlet valve proximate a bottom of the piston and an outlet valve proximate a top of the piston. A guide having a vertical displacement is arranged so that the piston travels along the guide. The guide has a compressed gas outlet proximate a bottom of the guide and is arranged to move gas into the piston when the piston contacts the compressed gas outlet. The guide has a release valve operator disposed proximate a top of the guide and is arranged to open the outlet valve when the piston contacts the release valve operator. A source of compressed gas in communication with the compressed gas outlet. The system has means for converting motion of the piston along the guide into either (i) motion of another object or (ii) electric power.
In some embodiments, the guide comprises a piston tube having liquid disposed therein, the piston disposed in the piston tube and sealingly engaged to an interior wall of the piston tube, and a recirculating tube disposed proximate the piston tube and in liquid communication with respective longitudinal ends of the tube.
Some embodiments further comprise a turbine disposed in a liquid flow path defined by the recirculating tube and the piston tube, wherein motion of liquid imparted by motion of the piston is converted to rotary motion of the turbine.
Some embodiments further comprise at least one wire, rope or cable coupled at one end to the top of the piston, the at least one wire, rope or cable passing through a sheave wheel.
In some embodiments, the at least one sheave wheel is rotationally coupled to an electric generator or a gas compressor.
In some embodiments, the at least one wire, rope or cable is coupled at another end to the bottom of the piston, the system further comprising at least one additional sheave wheel arranged to constrain the at least one wire rope or cable to move in a closed loop.
In some embodiments, the piston or the at least one wire, rope or cable comprises a magnet, the system further comprising at least one wire coil disposed proximate the piston or the at least one wire, rope or cable whereby motion of the magnet induces electric current in the at least one wire coil.
In some embodiments, the guide is disposed in a tube forming part of a support structure for a floating or bottom supported marine platform.
A method for energy generation and storage according to another aspect of this disclosure includes displacing water from an enclosed volume defined by an object with compressed gas at a first depth in a body of water, causing the object to rise from the first depth. When the object reaches a second, shallower depth in the body of water, the compressed gas is displaced with water, causing the object to sink from the second depth to the first depth. When the object rises and sinks, motion of the object is converted to at least one of another form of motion and electrical power.
In some embodiments, the converting motion comprises displacing water along a tube in which the object moves, and using the motion displaced water to operate a turbine.
In some embodiments, the turbine rotates a gas compressor or an electric generator.
In some embodiments, the converting motion comprises moving a wire, rope or cable in around a sheave wheel, and rotationally coupling the sheave wheel to a gas compressor or an electric generator.
In some embodiments, the wire, rope or cable is moved in a closed loop.
In some embodiments, the converting motion comprises moving a magnet or a wire coil attached to the object by a corresponding wire coil or magnet to induce electric current in the wire coil or the corresponding wire coil.
In some embodiments, the converting motion comprises moving a wire, rope or cable having a magnet attached thereto past at least one fixed placement wire coil to induce electric current in the fixed placement wire coil.
In some embodiments, the object comprises a piston. The piston moves in a tube within which the piston is sealingly disposed.
Other aspects and possible advantages will be apparent from the description and claims that follow.
Apparatus and methods according to the present disclosure will be described first with an explanation of the general structure of an apparatus and its principle of operation. Such explanation will be followed by a more detailed description of example embodiments.
A well-known method of transporting an object which defines an enclosed volume, for example a tank, or an inverted basin or dome, from one depth in a body of water to a shallower depth the water is to fill the enclosed volume defined by the object with air, displacing water from within the object. Displacing the water with air creates buoyancy that can lift the object in the water. To sink an air filled object in a body of water, air is typically replaced by water, until the object sinks due to gravity. An energy generating and storage device according to the present disclosure is based on alternately filling a piston with water and displacing the water to enable a piston to travel up and down within a tube. Such movement moves water within the tube so that the moving water can drive an energy converting device such as a turbine.
The present disclosure describes a system which in some embodiments may convert motion of an object by reason of making the object alternatingly buoyant and then non-buoyant into a different form of motion, or converting the motion into electric power directly. In some embodiments, motion of the object may be converted into motion of a liquid. Such embodiment comprises a long, liquid filled tube, which may be oriented vertically, wherein is disposed a piston, tank or chamber (“piston” hereinafter for convenience) that can travel up and down within the tube. The cross-section of the piston may be substantially the same as the cross-section of the tube such that moving the piston in the tube pushes liquid in the tube in the direction of motion of the piston. Volume behind the moving piston has reduced pressure into which liquid can flow. The piston tube and associated components may be submerged in a body of water such as a river, lake or the ocean. Also, this embodiment of the system may be disposed within one or more tubes built into a support structure of high buildings, or as structures placed externally on such buildings. Other possible embodiments may comprise one or more tubes disposed along steep mountain walls, or one or more tubes which form part of the support structure of floating or fixed offshore platforms for oil and gas extraction, wind turbines, or other fixed offshore structures used for power conversion, and the like.
The liquid in the piston tube may be seawater, fresh water, or other suitable liquid. If using greater density liquid than water, the energy generation will improve because the buoyancy of the piston when it is liquid filled will be greater. A second tube, called the circulation tube, is placed alongside the piston tube and is hydraulically connected to the piston tube proximate the lower and upper end of the piston tube.
The term “turbine” is used in this disclosure to describe a device creating rotary motion from liquid that is being moved by the piston, but those skilled in the art will understand that the motion of the liquid may be converted to another form of motion using devices other than turbines.
The liquid can be discharged and/or drawn into the piston tube using one or more turbines, e.g. similar to turbines used for hydroelectric power generation. Such turbines may be mounted on or within the circulation tube, at the interface between the circulation tube and the piston tube or within the piston tube.
Seals may be implemented on the exterior surface of the piston to reduce fluid bypass between the upper and lower side of the piston, thereby improving the efficiency of moving the liquid in the piston tube.
The system may automatically fill the piston with compressed gas or air when the piston lands in the lower end of the piston tube. Compressed gas or air may be supplied from the surface via a tube placed externally of the piston tube, or by compressed air placed at the lower end of the tube. When air displaces the liquid within the piston, water from inside the piston is expelled from the piston. As soon as there is sufficient air in the piston, the buoyancy of the piston will result in the piston traveling upward within the piston tube, drawing in liquid below and pushing liquid ahead of the travel direction. The displaced liquid will provide energy to rotate the turbine(s).
When the piston reaches the top of the piston tube, the air within is released from the top of the piston and is displaced with liquid. The displacing liquid makes the piston lose buoyancy, where it will sink by gravity to the bottom of the piston tube again. During piston sinking, the liquid moved in front of and behind the piston within the piston tube will provide energy to rotate the turbine(s).
Some embodiments may make more efficient use of the compressed air or gas that is used to displace liquid from the piston. Such embodiments may reuse the pressurized air or gas from within the piston instead of venting the air or gas to the outside environment when the piston reaches the top of its travel in the piston tube. When the air is released from the piston, which air is at a pressure at least as great as the hydrostatic pressure in the body of water where the piston tube is located, can be vented into one or several low-cost pre-booster tanks or other pressure sealed storage container. Such pre-booster tanks may be implemented as one or several tubes placed externally to the piston tube. The pre-booster tubes may be, for example, oil well tubulars such as 2-⅞″ outer diameter (OD) production tubing. Such tubing may be recycled tubes obtained from abandoned or reworked hydrocarbon producing wellbores.
The reciprocating motion of the piston in the piston tube will continuously repeat as long as compressed air or gas is supplied to the bottom of the piston tube, allowing the system to generate close to a continuous energy output. A plurality of such generator units can be placed close to each other, having pistons that are not motion-synchronized with each other. In this way, a plurality of such generator units may provide substantially continuous, uninterrupted power supply.
Energy generated by the rotating turbine(s) may be exported for one or more external uses, but a portion of the energy so generated may be used to operate a compressor for the air, because the air needs to have a sufficient pressure to evacuate the water from within the piston when the piston is at the lower end of the piston tube. In some embodiments, compressed air may be provided by prefilled bottles or tanks coupled to the compressed air supply tube.
The generator unit may also be used for storing energy from other such generator units or from other types of energy generating devices (e.g., wind turbines, solar panels, wave powered generators, etc.), where excess power from such other types of devices can be used to compress air required to operate the herein described power generator. Then, when power delivered from such other generating devices is insufficient for connected loads, the compressed air may be used to power the generator unit described herein.
An alternative to filling a piston with air, and releasing the air when the piston reaches an upper travel limit, is to release air below a sinking piston only. This will push the piston up in the piston tube, generating energy by displacing liquid in the tube. When the piston reaches the upper travel limit, the air is released from underneath the piston, resulting in this sinking into the piston holding tube again.
The speed of travel of the piston will depend on the pressure drop or flow restriction induced by the turbine(s) as well as moving liquid friction in the various connected tubes. Hence, the speed of piston travel can be controlled to some degree by changing these parameters as well as the amount of liquid or air moved within the piston.
The traveling piston, when sinking in the piston tube, can be hydraulically coupled to pre-booster tank(s), which means that the pressure generated in front of the piston is also assisting in pressurizing the air in the pre-booster tank(s).
The system described herein is contemplated being installed in the ocean, where the system may be suspended by floats disposed at or close to the water surface, and where the piston tube is anchored to the water bottom. Locating the generator system in the ocean as described provides the ability to add other power generating devices to the system, for example wave energy converters, compressors and the like. The entire system may be submerged at sufficient depth in the water, so that vessels can pass overhead without risk to the system.
In some embodiments, a system according to the present disclosure may be mounted in boreholes on land, along mountain walls, along high-rise building walls, etc.
A system according to the present disclosure may be used within tubular risers for floating or seafloor moored windmill power generating systems. Buoyancy for such windmills may be obtained by floats placed externally.
In addition, the support structure (also sometimes referred to as “jackets”) for floating or bottom-supported windmills, oil and gas extraction platforms, accommodation platforms, and the like, which have vertical and/or close to vertical tubes that form part of the jacket structure may be used in some embodiments to house the energy generation system described herein. Such jackets are known to be built from a number of tube sections, where one or several of such tube sections may be used to enclose the energy generation system, to contain pressurized air, etc. It will be understood that the jackets used to support one or several wind turbines may benefit from using the energy generator and storage system described herein when used to store energy, whether as compressed gas or otherwise.
Although the system described uses circulating liquid between the piston tube and recirculating tube, some embodiments may discharge the operating liquid to the sea via one or several power generating turbines when sea water is used as the circulating liquid. Such discharge can be performed when piston travels downward in the piston tube, where the liquid is discharged to the sea from the lower end of the piston tube. When the piston travels upward, the liquid may be discharged to the sea from the upper end of the piston tube. Seawater may also be drawn in from the surrounding water in the lower or upper end of the piston tube as the case may be.
It should also be noted that by having the air tube (or a tank) extending to a depth below the lower end of the piston tube, and venting the air tube to the water from the lower end of piston tube, the increased hydrostatic pressure within the air tube by the seawater will be higher than the pressure required to displace the fluid within the piston with air when initiating the lift of the piston. When the system is anchored to the water bottom, changes in tidal or wave height may provide extra pressure into the air tube that can be harvested to provide energy to further compress the air.
An additional source of energy may also be harvested by running the air releasing from the piston or injected into the piston through an air powered turbine.
Some embodiments may use a different mechanism to convert motion of the piston into other forms of motion. In one such embodiment, the piston may be connected to one or several cables, wires or ropes, where the cables, wires or ropes are drawn through a pulley system coupled to a power generating device. Wires, cables or ropes may also be coupled to the lower end of the piston, where they may exit the lower end of the piston tube through a pulley system, also generating power by movement of the cable, wires or ropes. The cables, wires or ropes in the upper end of the piston tube may have weights attached to such end, while the cables, wires or ropes in the lower end may have floats connected to such end. Another embodiment may have cables, wires or ropes connected externally to the piston tube, obviating the need for weights or floats.
The manner of using wires or ropes, as well as the previously described implementations having an untethered piston moving within a tube allows also for the introduction of a rod or tube in the center of the piston tube, where the piston moves externally to such rod or tube. Within the rod or tube, magnets and/or coils may be built in, connected be electrical cable(s) to any point, e.g., the water surface, where electric power may be used. Implementing coils and/or magnets in the piston will result in electricity being generated directly (rather than rotating a turbine) as the piston travels up and down. One or more magnets may be implemented in the piston, as well as magnets mounted into and along the piston tube. As the piston travels past these tube mounted magnets, electricity will be generated. The tube can be assembled in one continuous length, or it may be assembled using shorter sections of tube connected end to end. So-called internally flush type wellbore casing may be a suitable example of a structure used to assemble the piston tube because such tube structure will reduce fluid bypass when the piston travels across tubular connection joints. Such embodiments using magnets and coils to convert motion of the piston to electric power may omit the piston tube and the recirculation tube. In some embodiments, the piston tube may be substituted by a simple guide to constrain motion of the piston.
Tubes may be assembled at the location where the generator system is to be mounted, assembled on land or near shore in the ocean. The system in some embodiments may be towed to location in the same fashion as underwater pipelines are transported.
A piston tube 14 may extend a selected length, generally a matter of discretion for the designer. The orientation of the piston tube only requires that there be some vertical separation between the two longitudinal ends of the piston tube 14; it will be appreciated that the system 10 will perform best when the piston tube 14 is oriented vertically. The piston tube 14 may be any shape; as a matter of convenience it may be in the form of a cylinder, wherein the internal wall of the cylinder is smooth along its entire length. A piston 12 may be disposed in the piston tube 14 and be free to move longitudinally within the piston tube 14. The piston 12 may be shaped to facilitate sealing engagement with the interior wall of the piston tube 14 such that movement of the piston 12 within the piston tube 14 most efficiently moves liquid (e.g., sea water) within the piston tube 14 as the piston 12 moves therein. The piston 12 will be explained in more detail with reference to
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In light of the principles and example embodiments described and illustrated herein, it will be recognized that the example embodiments can be modified in arrangement and detail without departing from such principles. The foregoing discussion has focused on specific embodiments, but other configurations are also contemplated. In particular, even though expressions such as in “an embodiment,” or the like are used herein, these phrases are meant to generally reference embodiment possibilities, and are not intended to limit the disclosure to particular embodiment configurations. As used herein, these terms may reference the same or different embodiments that are combinable into other embodiments. As a rule, any embodiment referenced herein is freely combinable with any one or more of the other embodiments referenced herein, and any number of features of different embodiments are combinable with one another, unless indicated otherwise. Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible within the scope of the described examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
Continuation of International Application No. PCT/US2022/022813 filed on Mar. 31, 2022. Priority is claimed from U.S. Provisional Application No. 63/171,492 filed on Apr. 6, 2021. Both the foregoing applications are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63171492 | Apr 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2022/022813 | Mar 2022 | US |
| Child | 18482179 | US |
