Patent Application
20240101232
This invention relates in general to floating platforms. In particular, this invention relates to an improved floating offshore wind turbine (FOWT) platform having an improved mass damper system configured to mitigate unwanted dynamic responses from heel motion during operation.
Wind turbines for converting wind energy to electrical power are known and provide an alternative energy source for power companies. On land, large groups of wind turbines, often numbering in the hundreds of wind turbines, may be placed together in one geographic area. These large groups of wind turbines can generate undesirably high levels of noise and may be viewed as aesthetically unpleasing. An optimum flow of air may not be available to these land-based wind turbines due to obstacles such as hills, woods, and buildings.
Groups of wind turbines may also be located offshore, but near the coast at locations where water depths allow the wind turbines to be fixedly attached to a foundation on the seabed. Over the ocean, the flow of air to the wind turbines is not likely to be disturbed by the presence of various obstacles (i.e., as hills, woods, and buildings) resulting in higher mean wind speeds and more power. The foundations required to attach wind turbines to the seabed at these near-coast locations are relatively expensive, and can only be accomplished at relatively shallow depths, such as a depth of up to about 45 meters.
The U.S. National Renewable Energy Laboratory has determined that winds off the U.S. Coastline over water having depths of 30 meters or greater have an energy capacity of about 3,200 TWh/yr. This is equivalent to about 90 percent of the total U.S. energy use of about 3,500 TWh/yr. The majority of the offshore wind resource resides between 37 and 93 kilometers offshore where the water is over 60 meters deep. Fixed foundations for wind turbines in such deep water are likely not economically feasible. This limitation has led to the development of floating platforms for wind turbines. Known floating wind turbine platforms may be anchored to the seabed with mooring lines and provide some stability to the tower and turbine against external loading from wind, waves, and current, as well as loading associated with the dynamics of the wind turbine mounted thereon. Floating wind turbine platforms and the tower and turbine mounted thereon however, may still experience undesirable instability due to external loading from the wind, waves, and current.
It would be desirable therefore to provide a floating wind turbine platform with an improved mass damper system configured to mitigate unwanted dynamic responses from heel motion during operation.
This application describes various embodiments of a FOWT platform having an improved mass damper system configured to mitigate unwanted dynamic responses from heel motion during operation. In one embodiment, a barge-type wind turbine platform is capable of floating on a body of water and supporting a wind turbine thereon in combination with a heel tank damper includes a barge-type wind turbine platform having a keystone, a first pair bottom beams including two bottom beams connected to opposite sides of the keystone, a second pair of bottom beams including two bottom beams connected to opposite sides of the keystone, wherein the second pair of bottom beams has a longitudinal axis perpendicular to a longitudinal axis of the first pair of the bottom beams, and the combined first and second pairs of bottom beams define a foundation. Each bottom beam in the first and second pairs of bottom beams includes an outwardly extending portion at a distal end thereof a U-shaped ballast conduit is mounted or formed within each of the pairs of bottom beams and extends between the outwardly extending portions of each bottom beam of each pair of bottom beams. Each ballast conduit has ballast water therein, the ballast water extending from the outwardly extending portions of each bottom beam of each pair of bottom beams, such that a volume of air is defined between a surface of the ballast water in each outwardly extending portion and an outwardly facing wall of each outwardly extending portion, and an internal damping element is provided within each ballast conduit. A heel tank damper is defined by the ballast conduits and their respective internal damping elements.
In a second embodiment, a method of mitigating dynamic responses from heel motion in a barge-type wind turbine platform capable of floating on a body of water and supporting a wind turbine thereon includes a barge-type wind turbine platform having a keystone, a first pair bottom beams including two bottom beams connected to opposite sides of the keystone, a second pair of bottom beams including two bottom beams connected to opposite sides of the keystone, wherein the second pair of bottom beams has a longitudinal axis perpendicular to a longitudinal axis of the first pair of the bottom beams, the combined first and second pairs of bottom beams defining a foundation, wherein each bottom beam in the first and second pairs of bottom beams includes an outwardly extending portion at a distal end thereof, wherein the first and second pairs bottom beams define a foundation having a cruciform shape, wherein a U-shaped ballast conduit is one of mounted and formed within each of the pairs of bottom beams and extends between the outwardly extending portions of each bottom beam of each pair of bottom beams, and wherein each ballast conduit has ballast water therein, the ballast water extending from the outwardly extending portions of each bottom beam of each pair of bottom beams, such that a volume of air is defined between a surface of the ballast water in each outwardly extending portion and an outwardly facing wall of each outwardly extending portion, and an internal damping element within each ballast conduit. A heel tank damper is defined by the ballast conduits and their respective internal damping element. The method includes mitigating dynamic responses from heel motion by using the ballast water within the ballast conduits as a mass element that is allowed to oscillate in a predetermined direction.
In another embodiment, a barge-type wind turbine platform capable of floating on a body of water and supporting a wind turbine thereon in combination with a heel tank damper includes a barge-type wind turbine platform having four connected bottom beams that extend radially outwardly from central point and define a foundation having a cruciform shape, wherein each bottom beam includes an outwardly extending portion at a distal end thereof, wherein an outwardly facing wall of each outwardly extending portion includes an opening that extends between an interior of the outwardly extending portion and the atmosphere outside of the outwardly extending portion, and a cross shaped wall having four legs that extend vertically between a lower wall of each beam and an upper wall of each beam, the distal ends of each of the four legs are spaced apart from distal end walls of each beam. An integrated heel tank damper has multiple ballast conduits formed between the cross shaped wall and the walls of each beam, the ballast conduits defining multiple fluid flow paths within the foundation.
In an additional embodiment, a barge-type wind turbine platform capable of floating on a body of water and supporting a wind turbine thereon in combination with a heel tank damper includes a barge-type wind turbine platform having a keystone, a first pair bottom beams including two bottom beams connected to opposite sides of the keystone, a second pair of bottom beams including two bottom beams connected to opposite sides of the keystone, wherein the second pair of bottom beams has a longitudinal axis perpendicular to a longitudinal axis of the first pair of the bottom beams, the combined first and second pairs of bottom beams defining a foundation having a cruciform shape, wherein each bottom beam in the first and second pairs of bottom beams includes an outwardly extending portion at a distal end thereof, wherein a U-shaped ballast conduit is mounted or formed within each of the pairs of bottom beams and extends between the outwardly extending portions of each bottom beam of each pair of bottom beams, and wherein each ballast conduit has ballast water therein, the ballast water extending from the outwardly extending portions of each bottom beam of each pair of bottom beams, such that a volume of air is defined between a surface of the ballast water in each outwardly extending portion and an outwardly facing wall of each outwardly extending portion, an interior wall within each bottom beam that extends vertically between a lower wall and an upper wall of each bottom beam, and further extends longitudinally from distal end walls of each bottom beam to a vertically extending exterior wall of the keystone, and a cross-shaped wall within the keystone extends vertically between a lower wall and an upper wall of the keystone, wherein each leg of the cross-shaped wall is longitudinally aligned with one of the interior walls of the bottom beams, and wherein the exterior walls and each of the legs of the cross-shaped wall of the keystone have vertically extending fluid flow openings formed therein, and define an internal damping element. A heel tank damper system is defined by the combination of the ballast conduits and a plurality of fluid flow paths defined by the fluid flow openings in the walls of the keystone.
In a further embodiment, a semi-submersible wind turbine platform capable of floating on a body of water and supporting a wind turbine thereon in combination with a heel tank damper includes a semi-submersible wind turbine foundation having a keystone, three bottom beams that extend radially outwardly from the keystone, a center column mounted to the keystone, three outer columns mounted at distal ends of the bottom beams, wherein a space within the center column, each outer column, the keystone and the bottom beam therebetween define three generally U-shaped ballast conduits, and wherein each ballast conduit has ballast water therein, the ballast water extending from an upper portion of the center column to an upper portion of the outer columns, such that a volume of air is defined between a surface of the ballast water in each column and an outwardly facing wall of each column, and an internal damping element within each ballast conduit. A heel tank damper is defined by the combination of the three ballast conduits.
Various advantages of the invention will become apparent to those skilled in the art from the following detailed description, when read in view of the accompanying drawings.
The present invention will now be described with occasional reference to the illustrated embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein, nor in any order of preference. Rather, these embodiments are provided so that this disclosure will be more thorough, and will convey the scope of the invention to those skilled in the art.
The embodiments of the invention disclosed below generally provide improvements to floating offshore wind turbine (FOWT) platforms that include, but are not limited to, providing an improved mass damper system configured to mitigate unwanted dynamic responses from heel motion during operation.
As used herein, the term parallel is defined as in a plane substantially parallel to the horizon. The term vertical is defined as substantially perpendicular to the plane of the horizon.
As used herein, the term heel or heeling refers to a rotation resulting from the combined effects about the roll and pitch axes as may be caused by wind pressure, waves, and/or current.
The embodiments of the improved FOWT platforms described and illustrated herein are suitable for commercial scale floating turbines with a power capacity within the range of about 15 MW to about 30 MW. The improved FOWT platforms described and illustrated herein may also be suitable for commercial scale floating turbines with a power capacity greater than about 30 MW and less than about 15 MW. Advantageously, the improved FOWT platforms described and illustrated herein have an improved mass damper system configured to mitigate undesirable dynamic responses of the FOWT platforms, such as from heel motion during operation.
Referring to the drawings, particularly to
The illustrated FOWT platform 10 includes a hull or foundation 12 that supports a wind turbine tower 14. The wind turbine tower 14 supports a wind turbine 16. The foundation 12 is a barge-type foundation, and is structured and configured to float in a body of water. Accordingly, a portion of the foundation 12 will be above water when the foundation 12 is floating in the water. Mooring lines (not shown) may be attached to the FOWT platform 10 and further attached to anchors (not shown) in the seabed to limit to movement of the FOWT platform 10 on the body of water.
In the illustrated embodiment, the wind turbine tower 14 is tubular and may have any suitable outside diameter and height. In the illustrated embodiment, the outside diameter of the wind turbine tower 14 tapers from a first diameter at its base to a second, smaller diameter at its upper end. Alternatively, the outside diameter of the wind turbine tower 14 may have a uniform diameter. The wind turbine tower 14 may be formed from any desired material, including but not limited to steel, concrete, fiber reinforced polymer (FRP) composite material, and a composite laminate material. If desired, the wind turbine tower 14 may be formed in any number of sections 14A.
The wind turbine 16 may be conventional and may include a rotatable hub 18. At least one rotor blade 20 is coupled to, and extends outward from, the hub 18. The hub 18 is rotatably coupled to an electric generator (not shown). The electric generator may be coupled via a transformer (not shown) and an underwater power cable (not shown) to a power grid (not shown). In the illustrated embodiment, the hub 18 has three rotor blades 20. In other embodiments, the hub 18 may have more or less than three rotor blades 20. A nacelle 21 is attached to the wind turbine 16 opposite the hub 18.
Typically, a lower portion of the foundation 12 may be submerged at a depth within the range of about 30 ft to about 100 ft (about 9.1 m to about 30.5 m). Accordingly, a portion of the foundation 12 will be above water when the foundation 12 is floating, semi-submerged, in the water, and a portion of the foundation 12 is also below the waterline. As used herein, the waterline is defined as the approximate line where the surface of the water meets the FOWT platform 10.
The illustrated foundation 12 may be formed from four bottom beams 22 that extend radially outwardly from a keystone 24 and provide buoyancy. When assembled together, the bottom beams 22 and the keystone 24 define the foundation 12 having a cruciform shape, i.e., having the shape of a cross. Additionally, the keystone 24 supports the tower 14. The tower 14 may be mounted to the keystone 24 via a transition member 26, configured for example, as a steel tube.
If desired, a work platform 28 may be mounted at a base of the tower 14, and may include access-ways or catwalks 30 mounted around all or a portion of the base of the tower 14 and/or the work platform 28.
In the embodiments illustrated herein, the wind turbine 16 is a horizontal-axis wind turbine. Alternatively, the wind turbine may be a vertical-axis wind turbine (not shown). The size of the wind turbine 16 will vary based on the wind conditions at the location where the FOWT platform 10 is anchored and the desired power output. For example, the wind turbine 16 may have an output of about 15 MW. Alternatively, the wind turbine 16 may have an output within the range of from about 15 MW to about 30 MW. Additionally, the wind turbine 16 may have an output of less than about 15 MW or more than about 30 MW.
The illustrated keystone 24 is formed from pre-stressed reinforced concrete, and may include one or more internal cavities, described below. Any desired process may be used to manufacture the keystone 24, such as a spun concrete process or with conventional concrete forms. Alternatively, other processes such as those used in the precast concrete industry may also be used. The concrete of the keystone 24 may be reinforced with any conventional reinforcement material, such as high tensile steel cable and high tensile steel reinforcement bars or REBAR. Alternatively, the keystone 24 may be formed from high performance concrete, FRP, steel, or combinations of pre-stressed reinforced concrete, high performance concrete, FRP, and steel.
The illustrated bottom beams 22 are formed from pre-stressed reinforced concrete as described above. Alternatively, the bottom beams 22 may be formed from high performance concrete, FRP, steel, or combinations of pre-stressed reinforced concrete, high performance concrete, FRP, and steel. The bottom beams 22 may be formed having any desired length.
The keystone 24 and the bottom beams 22 may then be assembled and post-tensioned longitudinally to define pairs of bottom beams 22A and 22B, and thus the foundation 12. The keystone 24 and the bottom beams 22 may be post-tensioned by any desired post-tensioning method, thus applying a compressive force between the keystone 24 and the bottom beams 22.
As shown in
A first pair of the bottom beams 22A is shown in cross-section in
As shown in
Advantageously, the FOWT platform 10 having the heel tank damper 39 is configured to mitigate undesirable dynamic responses of the FOWT platform 10, such as from heel motion during operation.
The mitigation of undesirable dynamic responses, as described above, may be accomplished at least in part, by:
Referring now to
The illustrated foundation 42 may be formed from four bottom beams 44 that extend radially outwardly from the keystone 46 and provide buoyancy. When assembled together, the bottom beams 44 and the keystone 46 define the foundation 42 having a cruciform shape, i.e., having the shape of a cross. As described above, the keystone 46 supports the tower 14. The tower 14 may be mounted to the keystone 46 via the transition member 26.
If desired, the work platform 28 may be mounted at a base of the tower 14, and may include the access-ways or catwalks 30 mounted around all or a portion of the base of the tower 14 and/or the work platform 28. The keystone 46 and the bottom beams 44 may be formed and assembled as described above.
As shown in
Similar to the FOWT platform 10, each bottom beam 44 includes an outwardly extending portion 48 at a distal end thereof (upwardly extending when viewing
A first pair of the bottom beams 44A is shown in
As shown in
Referring again to
Advantageously, the FOWT platform 40 having the heel tank dampers 55 and 57 is configured such that the ballast water defines a mass element within the cruciform shape of the foundation 42 and the heel tank dampers 55 and 57 allow the foundation 42 to effectively operate with rigid body heel natural frequencies within its intended wave energy range. As used herein, rigid body heel natural frequencies are those frequencies associated with any combination of rigid body pitch or roll motion.
Additionally, the heel tank dampers 55 and 57 use the ballast water as a mass element that is arranged in a cross-tank configuration that allows for effective response mitigation about both pitch P and roll R axes of the foundation 42, as shown in
Referring now to
The illustrated foundation 62 may be formed from four bottom beams 64 that extend radially outwardly from the keystone 66 and provide buoyancy. When assembled together, the bottom beams 64 and the keystone 66 define the foundation 62 having a cruciform shape, i.e., having the shape of a cross. As described above, the keystone 66 supports the tower 14. The tower 14 may be mounted to the keystone 66 via the transition member 26.
If desired, the work platform 28 may be mounted at a base of the tower 14, and may include the access-ways or catwalks 30 mounted around all or a portion of the base of the tower 14 and/or the work platform 28. The keystone 66 and the bottom beams 64 may be formed and assembled as described above.
Similar to the FOWT platforms 10 and 40, each bottom beam 64 includes an outwardly extending portion 68 at a distal end thereof (upwardly extending when viewing
A first pair of the bottom beams 64A includes two bottom beams 64 connected to opposite sides of the keystone 66, and a second pair of the bottom beams 64B includes two bottom beams 64 connected to opposite sides of the keystone 66 and having a longitudinal axis perpendicular to a longitudinal axis of the first pair of the bottom beams 64A. The pairs of bottom beams 64A, 64B, including the keystone 66 connected therebetween, are generally hollow and define a generally U-shaped ballast conduits 72A and 72B, respectively, that extend between the outwardly extending portions 68 of each bottom beam 64 of each pair of bottom beams 64A, 64B.
As shown in
Referring now to
The illustrated foundation 82 may be formed from four bottom beams 84 that extend radially outwardly from central point 86 and provide buoyancy. When assembled together, the bottom beams 84 define the foundation 82 having a cruciform shape, i.e., having the shape of a cross. Additionally, although not shown in
As shown in
Referring now to
The leg 102 represents one portion of the foundation that will include an additional leg 102 having a longitudinal axis perpendicular to a longitudinal axis of the illustrated leg 102.
The illustrated leg 102 may be formed as one discrete member, or may be formed from two bottom beams (not shown) that extend outwardly from a keystone (not shown but similar to the keystone 66). As described above, the legs 102 provide buoyancy for the foundation. When assembled together, the legs 102 define the foundation having a cruciform shape, i.e., having the shape of a cross.
The leg 102 is formed as two side-by-side tanks, each defining heel tank dampers, including a first tank 104 and a second tank 106. The first tank 104 includes an outwardly extending portion 108 at each distal end thereof (upwardly extending when viewing
The second tank 106 is similar to the first tank 104 but is larger than the first tank 104, and includes an outwardly extending portion 114 at each distal end thereof (upwardly extending when viewing
The two legs 102 that are mounted perpendicularly to each other to form the foundation (not shown) are fluidly connected to each other.
The side-by-side ballast conduits 112 and 118 combine to define a heel tank damper 119 configured to allow the ballast conduits 112 and 118 to mitigate different frequencies. In the embodiment illustrated in
Referring now to
The FOWT platform 120 has an external shape and size similar to the FOWT platform 60 and includes a foundation 122 that supports the wind turbine 16 mounted on the wind turbine tower 14, as described above. The foundation 122 is a barge-type foundation, and is structured and configured to float in a body of water. Accordingly, a portion of the foundation 122 will be above water when the foundation 122 is floating in the water. Mooring lines (not shown) may be attached to the FOWT platform 120 and further attached to anchors (not shown) in the seabed to limit to movement of the FOWT platform 120 on the body of water.
The illustrated foundation 122 may be formed from four bottom beams 124 that extend radially outwardly from a keystone 126 and provide buoyancy. When assembled together, the bottom beams 124 and the keystone 126 define the foundation 122 having a cruciform shape, i.e., having the shape of a cross. As described above, the keystone 126 supports the tower 14. The tower 14 may be mounted to the keystone 66 via the transition member 26.
Similar to the FOWT platforms 10, 40, and 60 each bottom beam 124 includes an outwardly extending portion 128 at a distal end thereof (upwardly extending when viewing
A first pair of the bottom beams 124A includes two bottom beams 124 connected to opposite sides of the keystone 126, and a second pair of the bottom beams 124B includes two bottom beams 124 connected to opposite sides of the keystone 126 and having a longitudinal axis perpendicular to a longitudinal axis of the first pair of the bottom beams 124A. The pairs of bottom beams 124A, 124B, including the keystone 126 connected therebetween, define a plurality of generally U-shaped ballast conduits, described in detail below, that extend between the outwardly extending portions 128 of each bottom beam 124 of each pair of bottom beams 124A, 124B.
Each bottom beam 124 includes an interior wall 132 that extends vertically between a lower wall or base 134 and an upper wall 136 of each bottom beam 124, further extends longitudinally from distal end walls 125 of each bottom beam 124 to a vertically extending exterior wall 138 of the keystone 126, and upwardly into the outwardly extending portion 128 of each bottom beam 124.
The keystone 126 includes a cross-shaped wall 140 that extends vertically between a lower wall or base 142 and an upper wall 144 of the keystone 126. Each leg of the cross-shaped wall 140 is longitudinally aligned with one of the interior walls 132 of the bottom beams 124. The walls 138 and each of the legs of the cross-shaped wall 140 have vertically extending fluid flow openings 145 formed therein, and define an internal damping element.
Thus, as shown in
Referring now to
The FOWT platform 150 is substantially the same as the FOWT 10, and includes the keystone 24 and the bottom beams 22 that may be assembled and post-tensioned longitudinally to define the pair of bottom beams 154, as shown in
Thus, the combination of the ballast conduit 36, internal damping element 38, and the external damping element 152 define an integrated heel tank damper 156. The FOWT platform 150, and each of the embodiments of the FOWT platform described herein, may include any desired number of sensors, such as position, movement, and environmental condition sensors (not shown), and includes a controller, such as a computer, configured operate and monitor the sensors and to adjust any of the valve, pumps, orifices, and the like within the FOWT platform.
Advantageously, the response of the integrated heel tank dampers described herein, for example the integrated heel tank damper 156, may be set, tuned, and/or adjusted actively or passively via adjustments to the heel tank damper's 156 mass, or damping. As used herein, stiffness may be defined as any restoring force acting on the heel tank damper with the effect of returning the heel tank damper to its equilibrium position.
For example, the heel tank damper 156 may be actively or passively tuned by adjusting one or both of the external damping element 152 and the internal damping element 38.
The volume of air within each outwardly extending portion 32 of the pair of bottom beams 154 are therefore fluidly connected by the air duct 157, thus providing a bi-modal heel tank response from venting or cross-talk between the volume of air within each outwardly extending portion 32.
Referring now to
The FOWT platform 160 includes a foundation 162 having two pairs of bottom beams, one of which is illustrated at 164. The pair of bottom beams 164 includes a keystone 166 and two bottom beams 168 that may be assembled and post-tensioned longitudinally, as shown in
When assembled together, the two pairs of bottom beams 164 and the keystone 166 define the foundation 162 having a cruciform shape, i.e., having the shape of a cross. As described above, the keystone 166 supports the tower 14. The tower 14 may be mounted to the keystone 166 via the transition member 26.
Similar to the FOWT platforms 10, 40, and 60 each bottom beam 164 includes an outwardly extending portion 170 at a distal end thereof (upwardly extending when viewing
A generally U-shaped ballast conduit 172 is defined within the pair of bottom beams 164 and extends between the outwardly extending portions 170 of each bottom beam 164 of each pair of bottom beams 164. The ballast conduit 172 includes an internal damping element 174 at or near a center of the ballast conduit 172. The ballast conduit 172 is filled with ballast water, such as sea water. The internal damping element 174 may be any desired damping element, including but not limited to a gate valve, and a wall or partition having a movable or otherwise closable orifice therethrough. The ballast conduits 172 and their respective internal damping elements 174 define a heel tank damper 176.
The heel tank damper's 176 frequency response may be actively or passively tuned by adjusting the total mass of the damper heel tank damper 176, for example by adding or removing ballast water.
One or both of the internal damping element 38 and the external damping elements 152 may be actively or passively tuned to:
FOWT platform system response may be actively or passively monitored to identify and actively tune the heel tank damper, such as the heel tank damper 176, to mitigate effects from wave excitation, heel response, bending tower, or any other undesired system dynamics.
It will be understood that any of the embodiments of the FOWT platforms described herein may be used in combination with one or more external sensors, such as on a wave buoy (not shown). Thus, the heal tank damper's set points, such as the heel tank damper 176, may be actively tuned based on external measurements received from the wave buoy. Additional external sensors may also be provided on the FOWT platform, such as the FOWT platform 160.
Referring now to
The illustrated foundation 182 is formed from three bottom beams 184 that extend radially outwardly from a keystone 186 and provide buoyancy. When assembled together, the bottom beams 184 and the keystone 186 define the foundation 182. An interior or center column 188 is mounted to the keystone 186, and three outer columns 190 are mounted at or near the distal ends of the bottom beams 184. The center column 188 and the outer columns 190 extend outwardly (upwardly when viewing
Access-ways or catwalks 192 extend radially from, and are connected to, the center column 188, and are also connected to each of the outer columns 190. Access ladders 194 may mounted to one or more of the center column 188 and the outer columns 190.
If desired, support members or top beams (not shown) may extend radially from, and be connected to, the center column 188 and to each of the outer columns 190. When top beams are provided, the catwalks 192 may be mounted thereon.
An upwardly facing wall of each the center column 188 and the outer columns 190 may include an opening 196 that extends between an interior of the columns 188, 190 and the atmosphere outside of the columns 188, 190.
The columns 188, 190, the keystone 186, then the bottom beams 184 are generally hollow. The space within the center column 188, each outer column 190, the keystone 186, and the bottom beam 184 therebetween define a generally U-shaped ballast conduit 198. The combination of the three ballast conduits 198, defined by the three outer columns 190, the three bottom beams 184, the keystone 186, and the center column 188, define a heel tank damper 199. It will be understood that one or more of the keystone 186 and the bottom beams 184 may include any of the damper elements described herein above.
As shown in
It will be understood that the embodiments of the heel tank dampers described and illustrated herein may be integrally formed within any desired FOWT platform foundation, including, but not limited to a tension leg platform (TLP), barge, spar, semi-submersible, or hybrid concept such that mass consists of water ballast provided within the foundation or hull structure which is allowed to oscillate within a ballast conduit, such as shown by the arrows A in
Advantageously, a barge-type FOWT platform foundation, such as shown in
The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
| Number | Date | Country | |
|---|---|---|---|
| 63409885 | Sep 2022 | US |
