Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEMS AND METHODS FOR TIDAL ENERGY CONVERSION AND
ELECTRICAL POWER GENERATION USING A ROTATABLE DRAG PANEL
Inventors: Lynn Blodgett, Colin Bagley, and Jeff Blodgett
FIELD OF THE INVENTION
[0001] The present invention relates to a system and method for
generating electrical
power from renewable energy sources such as naturally occurring forces and,
more particularly,
to electrical energy generation from tidal actions using a rotatable drag
panel. In particular, the
present disclosure illustrates a system and method for converting kinetic
energy from ocean tidal
movements ¨ specifically, the lateral ebb and flow of water caused by the
constant and repeating
pattern of tidal changes ¨ into electrical energy or power that can be stored
and/or consumed.
The systems and methods of the present invention also relate to adjusting the
amount of kinetic
energy converted into electrical energy.
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BACKGROUND
[0002] Notwithstanding the significant drop in crude oil prices during
2014-15, the long
term trend in fossil fuel prices is likely to increase due to diminishing
global oil and gas reserves,
alternative (preferably renewable) energy generation systems have become an
increasingly
significant topic of interest for countries around the world, particularly as
fossil fuel production
threatens to continue unabated. As a result, significant time, resources, and
funding have been
invested to research and develop alternative electrical energy generation
systems utilizing such
renewable sources as solar power, water flow, wind power and the like to
supply ever-increasing
amounts of energy. One relatively untapped renewable energy source receiving
increased
attention is the potential energy that might be harnessed from ocean movement,
such as the
potentially endless energy source inherent in the constant tidal, wave, and/or
current flows of the
ocean.
[0003] The potential for generating electrical energy from the action of
ocean phenomena
generally comes in three sources: ocean thermal power, wave power, and tidal
power. Ocean
thermal power generation takes advantage of the difference in temperature
between cooler deep
water and warmer surface water that becomes heated by the sun; that thermal
differential is then
used to operate a heat engine for generating electricity. Ocean thermal power
generation,
however, is expensive, has very low thermal efficiencies, and may require
equipment that can be
an eye sore if located near populated areas. Furthermore, ocean thermal power
generation
requires large temperature gradients or differentials to function adequately.
In many areas of the
ocean, the actual thermal differential is not large enough to generate
significant amounts of
electrical energy to meet demand.
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[0004] Wave power generation takes advantage of the waves generated on
the ocean
surface when wind interacts at the free surface of the water. Wave power
generation is,
however, highly dependent on wavelength and thus only suitable to specific
locations of the
ocean where large wavelengths are present. Wave power is also unreliable
because wave quality
is irregular and difficult to forecast, leading to unreliable energy
generation. Similar to ocean
thermal power, wave power may cause noise or visual pollution if wave energy
generators are
located near a populated area.
[0005] Tidal power generation techniques are expected to take advantage
of the
differences in the surface level of an ocean or similar body of tidal water
due to the gravitational
effects of the moon. The vertical difference in the surface level during tidal
changes represents
potential energy that holds promise for electrical power generation, and is
particularly desirable
because it follows a relatively regular pattern. Technology using tidal action
as a source for
energy generation is still in its relative infancy. One known tidal energy
generation system
utilizes large turbines placed in tidal streams in order to take advantage of
the flow of water
during tidal changes. A tidal stream is a relatively fast-flowing body of
water that is created by
the rising and falling of the tide; the turbines are positioned to capture the
horizontal flow of
water and thereby generate electricity. The fast-flowing water is thus
directed through the
turbine, which rotates a shaft attached to a magnetic rotor that converts the
mechanical energy
into electrical energy. These turbines are relatively expensive and may also
require significant
maintenance over their lifetime, thus increasing operating costs.
[0006] Another known method of harnessing tidal energy involves the use
of a barrage.
A barrage is a large dam where water spills over the dam as the tide rises.
The overflowing
water may be passed through a turbine, which rotates a shaft attached to a
magnetic rotor that
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converts the mechanical energy into electrical energy. This process of using a
barrage suffers
from similar downsides as the tidal stream process and is limited to areas
where a dam may be
constructed such as tidal rivers, bays, and estuaries.
[0007] Other known tidal energy systems require the construction and
placement of
machinery such as hydraulics and moveable tanks that extend far above the
surface of the water,
such as described in U.S. Patent No. 5,426,332, U.S. Patent No. 5,872,406, and
U.S. Patent
Application Publication No. 2013/0134714. As another example, a known tidal
energy system
may require the construction of a large reservoir on land that must be filled
so that a large duct
system may capture the flow of water, as described in U.S. Patent 4,288,985.
Such tidal energy
systems require large structures that are built either above the water or on
shore, requiring
significant costs in engineering and land.
[0008] Prior tidal energy generation systems, such as the tidal energy
generation systems
described in U.S. Patent Application No. 15/143,440 (which is hereby
incorporated by reference
in its entirety), include assemblies for capturing energy from the vertical
rising and falling of the
tide using a buoyant displacement vessel and converting the energy into
electrical power using a
directional converter mounted on the displacement vessel. Other tidal energy
generation systems
include assemblies for capturing energy from the lateral ebb and flow of the
tide using a buoyant
displacement vessel having an immobile drag panel extending into the water and
converting the
energy into electrical power using a directional converter positioned at a
stationary location, such
as land. In such an arrangement, it may be experienced that tidal energy
generation systems
having immobile drag panels are difficult to rewind after having drifted out
in a particular
direction away from the stationary location. Moreover, the amount of
electrical power generated
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may be proportional to the speed of the water current and this amount may not
be capable of
being adjusted based on electrical power demand of consumers.
[0009] Present electrical supply infrastructure does not have the
capability to store
electricity, so electricity must be supplied as it is demanded. If more
electricity is supplied than
is demanded, the excess electricity goes to waste. A need therefore exists for
an efficient and
cost-effective energy conversion/electrical power generation system that can
capture the kinetic
energy of tidal action as the water ebbs and flows due to changing tidal
action and adjust the
amount of kinetic energy captured by the drag panel to produce a specific
amount of electrical
power from the captured energy to meet consumer demand for electrical power.
SUMMARY OF THE INVENTION
[0010] Disclosed herein is a novel tidal energy conversion assembly and
method for
generating electricity. Generally, the tidal energy conversion assembly may
generate energy
utilizing drift/drag forces from the ebb and flow of the tide and/or currents.
In an aspect of the
invention, the tidal energy conversion assembly may include a displacement
vessel having a drag
panel that is rotatable about a horizontal axis. In an embodiment, the
displacement vessel may
include a drag panel that is rotatable about the horizontal axis by a control
mechanism. The
control mechanism may be, for example, a motor, a winch, a hydraulic
mechanism, or a
pneumatic mechanism. In an embodiment, two or more control mechanisms may be
used to
rotate the drag panel about the horizontal axis. The drag panel may be coupled
to the
displacement vessel about the horizontal axis of rotation. In an embodiment,
the drag panel may
include arms extending therefrom connecting the control mechanisms to the drag
panel. In
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another embodiment, the drag panel may include a counterweight to assist in
the horizontal
rotation of the drag panel.
[0011] In another embodiment, the horizontally rotatable drag panel may
include one or
more vertically rotatable sub panels. The vertically rotatable sub-panels may
be used to reduce
the force necessary to retract the entire drag panel about the horizontal
axis. In an example,
before retracting the drag panel, the vertically rotatable sub-panels may be
rotated (preferably
by 90 degrees) and then the entire drag panel may be retracted out of the
water. Alternatively,
the vertically rotatable sub-panels may be used for steering purposes or to
adjust the amount of
drag force experienced by drag panel (and thus, electricity generated by the
directional converter
at the stationary location).
[0012] A tidal energy conversion assembly may include a displacement
vessel, a drag
panel coupled to the displacement vessel that is rotatable about a horizontal
axis, a directional
converter coupled to a generator positioned at a stationary location, and an
anchor cable having a
first end, a second end, and a length in between the first end and the second
end. The directional
converter may activate the generator to generate electricity when the
displacement vessel
changes its position relative to the stationary location. In an embodiment,
the displacement
vessel may include floatation devices connected by transverse members to
create a frame from
which to hold the rotatable drag panel as the displacement vessel floats in
the water. Any
number of floatation devices may be used to maintain buoyancy of the
displacement vessel and
to hold the weight of the drag panel in the water. In an embodiment, the
floatation devices are
pontoons. In another embodiment, the floatation devices may have a tubular or
cylindrical
shape.
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[0013] The present disclosure provides for a method of generating
electricity using the
flow of water due to tidal action. The method includes releasing a
displacement vessel having a
drag panel rotatable about a horizontal axis of the displacement vessel,
wherein the drag panel
extends at an angle from a surface of the water. In an embodiment, the drag
panel may extend
vertically into the water. The method further includes generating electricity
as the displacement
vessel travels due to the flow of water.
[0014] The present disclosure also provides for a method of adjusting the
amount of drag
force experienced by a drag panel of a displacement vessel. The method
includes releasing the
displacement vessel in a body of water and rotating the drag panel by an angle
about a horizontal
axis of the displacement vessel to thereby adjust the amount of drag force
experienced by the
drag panel. In an embodiment, the angle is greater than 0 degrees and less
than or equal to 90
degrees. In an embodiment, decreasing the angle between the drag panel and the
horizontal axis
decreases the amount of drag force experienced by the drag panel. In an
embodiment, increasing
the angle between the drag panel and the horizontal axis increases the amount
of drag force
experienced by the drag panel.
[0015] A tidal energy conversion system may include a plurality of the
foregoing
assemblies of displacement vessels and directional converters in order to
increase the potential
for power generation, using one or a plurality of generators.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing and other objects and advantages will be apparent
upon
consideration of the following detailed description, taken in conjunction with
the accompanying
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drawings, in which like reference characters refer to like parts throughout.
It will be appreciated
that certain reference characters herein have been changed from the priority
provisional
applications to provide better correspondence among analogous structures.
[0017] FIGS. 1A-1C show a tidal energy conversion assembly having a
directional
converter comprising a drag energy converter.
[0018] FIGS. 2A-2C shows an exemplary directional converters.
[0019] FIG. 3A shows an exemplary displacement vessel.
[0020] FIG. 3B shows an isometric view of an exemplary displacement
vessel.
[0021] FIG. 4A shows an exemplary displacement vessel having a vertically
rotatable
drag panel.
[0022] FIG. 4B shows an exemplary displacement vessel having multiple
vertically
rotatable drag panels.
[0023] FIGS. 5A-5C show an exemplary displacement vessel having a
horizontally
rotatable drag panel.
[0024] FIG. 5D shows an exemplary displacement vessel having a
horizontally rotatable
drag panel and vertically rotatable sub-panels.
[0025] FIGS. 6A-6C shows an exemplary displacement vessel having a
horizontally
rotatable drag panel in various positions.
[0026] FIG. 7A shows an exemplary retrieval mode with the drag panel
retracted.
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[0027] FIG. 7B shows an exemplary retrieval mode with the drag panel fully
deployed.
[0028] FIG. 8 shows an exemplary displacement vessel having an array of
directional
converters and generators on land.
[0029] FIG. 9 shows a graph of velocity of water current and drag panel
angle to
maintain a specified drag force.
DETAILED DESCRIPTION OF THE INVENTION
[0030] A tidal energy conversion device of the present invention generally
includes a
displacement vessel having a drag panel that is rotatable about a horizontal
axis. The
displacement vessel structure may include one or more buoyant floatation
devices that are
connected via transverse members to create a frame from which to hold the drag
panel as the
displacement vessel floats in the water. In an embodiment, the floatation
devices are pontoons.
In another embodiment, the floatation devices have a tubular or cylindrical
shape. The drag
panel may be coupled to the displacement vessel at an axis of rotation, such
as the horizontal
axis. In an embodiment, the drag panel may be disposed between two buoyant
floatation devices
and connected thereto to form the displacement vessel.
[0031] The drag panel generally extends from the displacement vessel in a
generally
downwards direction (into the water) in order to capture drag forces caused by
the flow of water.
As explained above, the drag panel is rotatably coupled to the displacement
vessel via the
floatation devices along a horizontal axis such that the drag panel may freely
rotate about the
horizontal axis from an active configuration (e.g., drag panel in the water)
to a retracted
configuration (e.g., drag panel out of the water).
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[0032] In an embodiment, the displacement vessel may include a drag panel
that is
rotatable about the horizontal axis by a control mechanism. The control
mechanism may be, for
example, a motor, a winch, a hydraulic mechanism, a pneumatic mechanism, or
any other
suitable control mechanism as is known in the art. In an embodiment, two or
more control
mechanisms may be used to rotate the drag panel about the horizontal axis. In
an embodiment,
the drag panel may include arms extending therefrom connecting the control
mechanisms to the
drag panel to provide a lever from which the control mechanism may rotate the
drag panel. In
another embodiment, the drag panel may include a counterweight to assist in
the horizontal
rotation of the drag panel.
[0033] In another embodiment, the horizontally rotatable drag panel may
include one or
more vertically rotatable sub panels. The vertically rotatable sub-panels may
be used to reduce
the force necessary to retract the entire drag panel about the horizontal
axis. In an example,
before retracting the drag panel, the vertically rotatable sub-panels may be
rotated (preferably by
about 90 degrees) and then the entire drag panel may be retracted out of the
water. Alternatively,
the vertically rotatable sub-panels may be used for steering purposes or to
adjust the amount of
drag force experienced by drag panel (and thus, electricity generated by the
directional converter
at the stationary location).
[0034] The horizontally rotatable drag panel and horizontally rotatable
drag panel with
vertically rotatable sub-panels embodiments of the present invention may be
applied to any of
the below devices, systems, and assemblies of displacement vessels having drag
panels, such as
the displacement vessels detailed in FIGS. 1 and 3-8.
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[0035] The drag panel generally increases the surface area upon which
drag forces act
due to the ebb and flow caused by tidal action (or drag forces caused by other
ocean currents),
allowing the displacement vessel to be more effectively moved by the drag
forces caused by the
ebb and flow of the water. The drag panel may have a height that is between 1
ft and 100 ft, and
preferably extends the entire width of the displacement vessel. The thickness
of the drag panel
may be between 0.1 inch and 24 inches; however, one skilled in the art will
recognize that any
suitable thickness may be used. In an example, the drag panel may be
fabricated from an
extruded metal sheet panel or other durable structure.
[0036] Generally, the tidal energy conversion assembly includes a
directional converter
for converting the lateral motion of the displacement vessel into electrical
power. The
directional converter may be housed on the displacement vessel or located away
from the
displacement vessel, such as on land. As an example of the operative coupling,
the directional
converter may include a rotatable drum fixed on an axle, with at least a
portion of the anchor
cable wrapped around the drum. The displacement vessel may be coupled by one
or more
anchor cables to one or more directional converters positioned at a stationary
location, such as
land, for example. The stationary location may be a bay/ocean floor, a barge,
a pier, a platform,
or any other suitable location. Each of the directional converters may include
a drum around
which the anchor cables are wound, a gear box operatively coupled to the drum,
and a generator
operatively coupled to the gear box. Thus, the displacement vessel may be
attached to an array
of generators. The generators may have similar electrical output ratings or
may have different
electrical output ratings. If different electrical output ratings are used,
each of the generators
may be controllably engaged or disengaged based on, for example, the speed of
the current.
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[0037] In this instance, as the ebb and flow of the tide causes the
displacement vessel to
drift in a lateral direction relative to the stationary location, the anchor
cable causes the drum to
rotate as the anchor cable unwinds and the resulting mechanical energy (e.g.,
rotational kinetic
energy) of the directional converter is transmitted to the generator for
producing electrical
energy.
[0038] Generally, the directional converter may utilize a gearing
mechanism having at
least one sprocket on an axle or a spindle, and a gear box. The gear box
converts an input
rotations per minute (RPM) into an output RPM that is different than
(preferably greater than)
the input RPM to increase the rotational energy transmitted to the generator.
This may be
accomplished by using a series of gears of differing radii coupled to one
another or via a chain,
for example. The gearing mechanism or alternatively, the gear box, may include
a gear
multiplication arrangement in order to increase the output RPM of the
directional converter and
applied to the generator.
[0039] The generator may include a fixed magnet (or permanent magnet)
generator. A
fixed magnet generator includes a permanent magnet fixed to a shaft and housed
within a
stationary armature. The armature includes one or more metal wires/coils
within the magnetic
field of the permanent magnet such that, upon rotation of the permanent
magnet, an electric
current is induced in the wires. A fixed magnet generator may be suitable for
generating
electricity using a lower rotational speed, such as a rotational speed of
under 1000 RPM, for
example. As another embodiment, the generator may include any suitable
electrical generator as
is known in the art, including but not limited to an induction generator
(e.g., a doubly-fed
induction generator or permanent magnet generator) or other electric
generator.
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[0040] Generally, the tidal energy generation assembly may include a
displacement
vessel that is rotatably coupled by an anchor cable to a directional converter
positioned at a
stationary location, such as land, for example. Because the speed and
direction of water varies
during a tidal cycle, the displacement vessel may require rotation to orient
itself with respect to
the flow of water. This rotation may be achieved using a series of control
cables attached to the
displacement vessel ¨ forming a "bridle" - such that the displacement vessel
may capture both
directions of water flow. The control cables allow the displacement vessel to
rotate about a
vertical axis and thus capture drag forces from the flow of water in multiple
directions.
Additionally, the displacement vessel may rotate such that it operates at an
angle to the direction
of water flow to adjust the amount of drag force exerted on the displacement
vessel, and thus
adjust the amount of electricity generated at the generator. The displacement
vessel includes a
drag panel supported by one or more floatation devices configured to float at
or near the surface
of the water. The drag panel may include one or more non-flat sides configured
to capture drag
forces more effectively than a flat side. In an example, the sides of the drag
panel may include a
parabolic shape, a concave shape, or a lofted cut. In light of the foregoing,
a skilled person will
appreciate that other shapes may be appropriate to use.
[0041] The bridle may include any suitable number of control cables
(e.g., two, four,
eight, etc.) and each control cable may be connected to the displacement
vessel at a connection
point. Exemplary connection points along the displacement vessel may include
the ends or sides
of the displacement vessel. For potentially maximum adjustability to the angle
of motion, a 4-
point harness can be used so that the drag panel can be rotated about a
vertical axis and one or
more horizontal axis. Redundant cables (and control mechanisms) may be used to
create an 8-
point harness to improve reliability and/or adjustability of the system. The
displacement vessel
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may further house a control mechanism, such as a motor, a winch, or a drum and
spring affixed
to an axle, for example, to wind up and/or release the control cables and
effect rotation of the
displacement vessel.
[0042] In addition, with suitable placement of anchored cables on
generally opposite
sides of the assembly, electrical power generation may be produced as the
assembly moves in
both directions (incoming and outgoing tides) - i.e., the cables can be
mounted on different
drums on the directional converter such that as one cable unwinds and operates
the generator, the
other cable is being re-wound for the next tidal cycle.
[0043] A method of generating electricity using the flow of water due to
tidal action may
include releasing a displacement vessel having a drag panel rotatable about a
horizontal axis of
the displacement vessel, wherein the drag panel extends at an angle from a
surface of the water.
In an embodiment, the drag panel may extend vertically into the water. The
method further
includes generating electricity as the displacement vessel travels due to the
flow of water.
[0044] A method of adjusting the amount of drag force experienced by a
drag panel of a
displacement vessel may include releasing the displacement vessel in a body of
water and
rotating the drag panel by an angle about a horizontal axis of the
displacement vessel to thereby
adjust the amount of drag force experienced by the drag panel. In an
embodiment, the angle is
greater than 0 degrees and less than or equal to 90 degrees. In an embodiment,
decreasing the
angle between the drag panel and the horizontal axis decreases the amount of
drag force
experienced by the drag panel. In an embodiment, increasing the angle between
the drag panel
and the horizontal axis increases the amount of drag force experienced by the
drag panel.
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[0045] A tidal energy conversion system may include a plurality of the
foregoing
assemblies of displacement vessels and directional converters in order to
increase the potential
for power generation, using one or a plurality of generators.
[0046] FIGS. 1A-1C show a tidal energy conversion assembly 100 having a
displacement
vessel 102 that is buoyant at the surface 118 of the water and houses or
supports a directional
converter 109. Generally, the directional converter 109 is capable of
capturing the drag ¨ or
"drift" ¨ of the tidal energy conversion assembly caused by the ebb and flow
of water due to tidal
action. The displacement vessel 102 is anchored to the stationary location 106
at anchor 108 by
anchor cable 103. The directional converter 109 may comprise any of the
embodiments
described and shown below, for example, FIGS. 2A-2C. The displacement vessel
102 further
includes an electric power generator for generating electricity from the drag.
The anchor
cable 103 has a first end at latch 107 and a second end connected to
directional converter 109,
defining a length therebetween. Anchor cable 103 is threaded through the
anchor 108 (which
can be either a loop or a pulley).
[0047] Generally, the directional converter 109 includes a drum 113 and
control
mechanism 120. FIG. 2A shows an enlarged view of the directional converter 109
configured
for drag energy conversion.
[0048] In FIG. 1A, displacement vessel 102 is resting at a point directly
above
anchor 108 at a distance 119a above the anchor 108. Anchor cable 103 has a
length L1 from
displacement vessel 102 to anchor 108. Tidal drag forces may shift
displacement vessel 102 in a
lateral direction 122a with respect to its original position. When the tide
rises vertically as
shown in FIG. 1B, displacement vessel 102 rises to a distance 119b, which is
greater than
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distance 119a, and the tide pushes the displacement vessel 102 a lateral
distance of H1. The
anchor cable 103 increases to a length of L2 between the displacement vessel
102 and
anchor 108. L2 is greater than L1 and 119b is greater than 119a. The increase
in distance of L1
to L2 causes the drum 113 of the directional converter 109 to rotate. This
rotation of the spindle
can be transmitted to an electrical power generator to generate electricity.
As the tide returns, the
displacement vessel 102 returns to the position over anchor 108, for example,
by the use of a
positioning system on the displacement vessel 102. Slack in the anchor cable
105 may be
brought into and stored within the displacement vessel 102 by a control
mechanism 120, e.g., a
motor or a spring coupled to the drum 113.
[0049] In FIG. 1C, the displacement vessel 102 is resting at a low point
in the tidal cycle
at a distance 119c between the displacement vessel 102 and the anchor 108. and
anchor
cable 103 has a length L3 from the displacement vessel 102 to the anchor 108.
When the tide
falls vertically as shown in FIG. 1C, the tides drags the displacement vessel
102 a lateral distance
of H2 in direction 122b and the displacement vessel 102 falls vertically to a
distance 119c. The
length L3 may increase in length due to the falling tide Where L3 is greater
than L1, the increase
in length from L1 to L3 causes the drum 113 of the directional converter 109
to rotate. The
rotation can be captured by an electrical power generator to generate
electricity. As the tide
returns, the displacement vessel 102 returns to the position over anchor 108,
for example, by the
use of a positioning system on the displacement vessel 102. Any slack in the
anchor cable may
be returned to the drum 113 by a control mechanism 120.
[0050] Generally, the displacement vessel 102 is capable of connecting,
disconnecting,
and/or reconnecting to different locations (e.g., different anchors) along the
seabed as the
displacement vessel drifts in a lateral direction relative to a first
stationary location on the
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seabed. Initially, the displacement vessel 102 may be anchored to the first
stationary location
along the seabed by a first anchor cable attached to a first anchor. As the
displacement vessel
102 moves in a lateral direction due to the ebb and flow of water during tidal
action, the anchor
cable 103 may disconnect from the first anchor and reconnect to a second
location, such as a
second anchor, along the seabed closer to the drifted-to location of the
displacement vessel. To
do so, the anchor cable may include a connection mechanism at an end of the
anchor cable that
connects the anchor cable to the first anchor attached to the seabed. The
connection mechanism
on the end of the anchor cable may disconnect from the first anchor, translate
relative to the
seabed via a linking mechanism, such as a guide cable or chain, and then
reconnect to the second
anchor. For example, the connection mechanism may include a latch, clip, pin,
rolling
mechanism, and/or lock. The connection mechanism may further include a control
mechanism,
such as a motor, to assist in the connecting, disconnecting, and/or
reconnecting of the anchor
cable to various locations on the seabed. The linking mechanism may reconnect
the anchor cable
to a second anchor (not shown) at the second location.
[0051] Generally, the displacement vessel 102 may include a drag panel
121 extending
from one of the exterior surfaces of the displacement vessel 102. The drag
panel 121 may
enhance capture of tidal currents and/or allow for the additional capture of
currents that occur
deeper in the water, such as undertow. The additional drag that is captured by
the drag panel 121
may provide additional forces that can be converted into mechanical energy by
the directional
converter and ultimately, electricity by the electrical power generator. For
example, a drag panel
121 may be secured to a bottom side of the displacement vessel 102 and extend
in a generally
downwards direction. The drag panel 121 may be substantially parallel to a
side of the
displacement vessel or at an angle relative to a side of the displacement
vessel. The drag panel
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121 may extend along an entire width of the bottom surface of the displacement
vessel or only a
portion of the width. Furthermore, the drag panel 121 may include support
structures, such as
reinforcement bars, that may extend from the displacement vessel to any point
on the drag panel
121.
[0052] The drag panel 121 may include a control mechanism such that the
control
mechanism may deploy and retract the drag panel 121 from the displacement
vessel. For
example, the drag panel 121 may be stored within the displacement vessel in a
first stored
position. The control mechanism may controllably deploy the drag panel 121 at
a specified time,
such as a time when strong current conditions exist, to a second deployed
position. If the drag
panel 121 is not needed, the control mechanism may retract the drag panel 121
back into the first
position inside the displacement vessel. The first position may alternatively
be a configuration
where the drag panel 121 is substantially adjacent to a surface of the
displacement vessel 102.
The drag panel 121 may be deployed to the second position by rotation about a
hinge, where the
rotation is controlled by the control mechanism. The control mechanism may
include hydraulics
or an electric motor that may be powered by the energy generated by the
displacement
vessel 102.
[0053] Generally, the directional converter may include a plurality of
drums and a
plurality of anchor cables to utilize the lateral motion in multiple
directions to generate
electricity. The plurality of drums and the plurality of anchor cables may be
employed in various
orientations in the displacement vessel or outside the displacement vessel
such that as one cable
unwinds from one drum and operates the electrical power generator, another
cable is rewound on
a different drum prepping for the next tidal cycle. In this way, a first drum
may be engaged with
the electrical power generator to produce electricity when the displacement
vessel drifts in one
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direction, and a second drum may be engaged to produce electricity when the
displacement
vessel drifts in a different direction. This particular configuration of
multiple drums housed
within or outside the displacement vessel and multiple anchor cables fixed at
various locations
along the seabed or on land may allow the displacement vessel to take
advantage of the lateral
motion of the displacement vessel in multiple lateral directions due to the
ebb and flow of the
water during tidal action. Alternatively, the two drums may be operatively
coupled such that the
second cable may be automatically rewound on its drum as the cable on the
first drum is
unwound and thus be ready for unwinding as the displacement vessel moves in
the
other/opposite direction.
[0054] For example, two drums ¨ each attached to at least one anchor
cable ¨ may be
disposed in the displacement vessel such that as the displacement vessel moves
laterally in a
first direction, a first anchor cable unwinds from the first drum causing the
first drum to rotate
while a second anchor cable (fixed to a second stationary location) may be
reeled into a second
drum by, for example, a control mechanism (for example, a spring or motor).
The rotation of the
first drum due to the first anchor cable unwinding is transferred to an
electrical power generator
to generate electricity as the displacement vessel moves in the first lateral
direction. As the ebb
and flow of the water during tidal action cause the displacement vessel to
drift in a second lateral
direction, the second anchor cable is unwound from the second drum causing the
second drum to
rotate as the first anchor cable is reeled back into the first drum by a
control mechanism as
described above. The rotation of the second drum is transferred to the
electrical power generator
which generates electricity as the displacement vessel moves in the second
lateral direction. The
second anchor may be reeled back into the second drum when the displacement
vessel moves
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again in the first direction. Thus, electric power can be generated during
both general directions
of travel.
[0055] FIG. 2B illustrates a directional converter 209 that may be placed
at a stationary
location, such as land or a barge. In particular, directional converter 209
includes a rotatable
drum 213 fixed on an axle 215. An anchor cable may be coupled to the rotatable
drum such that
it may be wound about or unwound from the drum 213. A drive gear 212 is also
fixed on the
same axle 215 as the rotatable drum 213. Drive gear 212 is connected to a
gearing mechanism
214 by a chain, for example, and gearing mechanism 214 includes a plurality of
gears 214a-214c.
In the directional converter 209, the gearing mechanism 214 is configured as a
gear
multiplication arrangement. As the drive gear 212 turns at a first RPM, gear
214a will turn at a
second RPM that is faster than the first RPM because gear 214a has a smaller
diameter than the
drive gear 212. Gear 214b is fixed on the same axle as gear 214a and thus will
also rotate at the
second RPM. Gear 214c is coupled to gear 214b by a chain and will spin at a
third RPM that is
faster than the second RPM, because the diameter of gear 214c is smaller than
the diameter of
gear 214b. The gearing mechanism 214 is also coupled to an electrical power
generator 216
such that rotation of the drum 213 is transferred to the electrical power
generator 216 through the
gearing mechanism 214 to generates electricity.
[0056] FIG. 2C illustrates yet another embodiment of a directional
converter 209.
Similar to the directional converters described above, directional converter
209 includes a
drum 213 around which an anchor cable may be wrapped, a drive gear 212, a
gearing
mechanism 214, and generators 216a-216e. In an embodiment, the directional
converter 209
may further include a level winder assembly 248 configured to maintain a
uniform wrapping of
the anchor cable 203 as it is wound around its respective drum 213 by
directing each wrap of the
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anchor cable 203 around the drum 213 to sit tightly next to the previous wrap.
The level winder
assembly 248 may include a guide mechanism that guides the anchor cable as it
is wound
around the drum 213 so that it is wound evenly across the drum 213. In an
embodiment, the
guide mechanism may include a plate with a slot in which the anchor cable
passes through. The
guide mechanism may further include two or more oppositely-positioned vertical
rollers to
prevent lateral movement of the anchor cable. The guide mechanism may be
coupled to one or
more axles that are in turn coupled to the drive gear 212 (and, optionally, a
gearing mechanism)
such that one full rotation of the drum 213 causes the guide mechanism to
travel a specified
length of the drum 213 in a first direction along the rotational axis of the
drum. The specified
length that the guide mechanism travels may be a function of the diameter of
the anchor
cable 213. After the guide mechanism has traveled one full length of the drum
213, the guide
mechanism may switch its direction of travel and move in a second direction
that is opposite the
first direction. After the guide mechanism travels the length of the drum in
the second direction,
this process may be repeated. The one or more axles may include grooves or
threads arranged in
a corkscrew around the axle. The level winder assembly 248 may travel in the
first direction
along a first groove and, after travelling one full length of the drum, the
level winder assembly
may travel along a second groove that crosses the first groove.
[0057] The directional converter 209 may utilize a gearing mechanism
having at least
one sprocket on an axle or a spindle, and a gear box. The gear box converts an
input rotations
per minute (RPM) into an output RPM that is different than (preferably greater
than) the input
RPM to increase the rotational energy transmitted to the generator. This may
be accomplished
by using a series of gears of differing radii coupled to one another or via a
chain, for example.
The gearing mechanism or alternatively, the gear box, may include a gear
multiplication
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arrangement in order to increase the output RPM of the directional converter
209 and applied to
the generator 216. The electric generator(s) 216 may require a faster
rotational input than can be
provided by a relatively simple gearing mechanism that does not include a gear
multiplication
arrangement. Thus, a slower RPM of the drum may be converted into a faster RPM
by a gear
multiplication arrangement to cause greater RPM transferred to the generator.
The gear
multiplication arrangement may include a series of gears of differing radii
that are coupled to one
another by a chain, for example, such that an input gear has a larger radius
with a slower RPM
while an output gear has a smaller radius and a faster RPM.
[0058] The electrical generator(s) 216 may include a fixed magnet (or
permanent
magnet) generator. A fixed magnet generator includes a permanent magnet fixed
to a shaft and
housed within a stationary armature. The armature includes one or more metal
wires/coils within
the magnetic field of the permanent magnet such that, upon rotation of the
permanent magnet, an
electric current is induced in the wires. A fixed magnet generator may be
suitable for generating
electricity using a lower rotational speed, such as a rotational speed of
under 1000 RPM, for
example.
[0059] In another embodiment, also shown in FIG. 2C, the directional
converter may
include a rewind assembly 262. The rewind assembly 262 may be directly coupled
to the drum
213 so as to rotate the drum 213 and rewind the anchor cable and displacement
vessel. The
rewind assembly may be implemented using any known technique in the art, such
as, a hydraulic
motor. The rewind assembly may include a detachable coupling so that the
rewind assembly is
selectively coupled to the drum 213. In this case, the detachable coupling
will be connected to
the drum 213 during rewinding and can be detached while the displacement
vessel is generating
electricity.
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[0060] FIG. 3A shows a top view of a displacement vessel 302 that is
rotatable in the
water. The displacement vessel 300 may be adapted to float in the water by way
of a floatation
device as described above and below. The displacement vessel 300 includes a
drag panel 302
having a first side 302a and a second side 302b that are adapted to capture
drag forces from the
flow of water due to tidal action and/or other water flows. The first side
302a and second side
302b are shown as substantially flat, but may be adapted to have any suitable
shape to enhance
(or reduce) the capture of drag forces as will be described in more detail
below.
[0061] Because the speed and direction of water varies during a tidal
cycle, the
displacement vessel may be rotated to orient itself with respect to the flow
of water in order to
maximize the force of the water captured by the displacement vessel or
otherwise control the
amount of force captured by the drag panel depending on prevailing current
conditions.
[0062] This rotation may be achieved using control cables attached to the
sides of the
displacement vessel ¨ forming a "bridle" - such that the shortening or
releasing of the length of
the control cable(s) allow the displacement vessel to turn, rotate, or
otherwise change the angle
of the drag panel relative to water flow. The control cables may be attached
at the ends or sides
of the displacement vessel using any suitable number of connection points to
connect the
displacement vessel to the anchor cable. In an example described in more
detail below, the
displacement vessel includes four connection points corresponding to four
separate control
cables and the connection points may be generally located at corners of the
displacement vessel.
In another example described in more detail below, the displacement vessel may
include
redundant control cables (and, if desired, redundant control mechanisms) such
that the
displacement vessel may have eight control cables generally connected at the
corners of the
displacement vessel. The control cables may be attached to the displacement
vessel by a control
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mechanism, such as a motor or winch, for example, configured to independently,
or
cooperatively control (i.e., adjust) the length of the control cables. The
control mechanism may
be mounted in or on the displacement vessel. Continuing the example from
above, four control
mechanisms may be mounted on the displacement vessel at each of the four
connection points to
independently control the four control cables. The control mechanism may
lengthen or shorten
the control cables, causing rotation of the vessel and thereby decrease or
increase the distance
between the end of the displacement vessel attached to the control cable and
the anchor cable.
The displacement vessel may include redundant cables connected to redundant
control
mechanisms to ensure operability in the event that a cable breaks or a control
mechanism
malfunctions.
[0063] The bridle ¨ or series of control cables ¨ may include any
suitable number of
control cables and each control cable may be connected to the displacement
vessel at a
connection point. Exemplary connection points along the displacement vessel
may include the
ends, corners, or sides of the displacement vessel. As stated above, control
mechanisms may be
attached to the displacement vessel at the connection points and each control
mechanism may
connect the displacement vessel to an individual control cable. Because each
control mechanism
may independently shorten or lengthen (wind or unwind) its respective control
cable, the bridle
may control the orientation of the displacement vessel in the water. In
particular, the bridle may
be used to change the angle of attack of the displacement vessel with respect
to the water/current
flow, e.g., the yaw, pitch, and/or roll. For example, the pitch of the
displacement vessel may be
changed to point the displacement vessel in a downwards direction to cause the
displacement
vessel to submerge or dive deeper into the water if already submerged. As an
example of a
method of pointing the displacement vessel downwards, one or more control
mechanisms
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generally located at the top of the displacement vessel may wind control
cables in. Additionally,
or optionally, one or more control mechanisms located generally at the bottom
of the
displacement vessel may unwind control cables to effect a change in the pitch
of the
displacement vessel. A similar process may be used to rotate the displacement
vessel upwards to
cause the displacement vessel to surface or decrease its depth in the water.
[0064] To illustrate the general case of controlling the angle, the
displacement vessel 300
further includes control cables 308a and 308b extending from the drag panel
302 adapted to
controllably adjust the orientation of the drag panel 302 in the water. The
control cables 308a
and 1008b may be coupled to an anchor cable 303 at one end via a coupling
mechanism 309 and
the anchor cable 303 may be further connected to a directional converter and a
generator at a
stationary location, as described above. Each control cable 308a and 308b may
also be coupled
at another end to a/an adjustment/control mechanism (indicated generally as
320a and 320b)
mounted on or within the displacement vessel 302, such as a motor and drum
assembly or a
winch, for example. Each control mechanism 320a and 320b may independently
wind up and/or
release its respective control cable to effect rotation of the displacement
vessel in the water. For
example, a first control mechanism 320a may wind up (or shorten) control cable
308a while a
second control mechanism 320b releases (or lengthens) control cable 308b, thus
rotating the
displacement vessel 302 in a clockwise direction and controllably adjusting
the amount of drag
force exerted on the drag panel 302. The first control mechanism 320a and
second control
mechanism 320b may also rotate the displacement vessel 302 in the opposite
(counterclockwise)
direction by the reverse operation, i.e., the first control mechanism 320a may
release control
cable 308a and the second control mechanism 320b may wind up control cable
308b. Those
skilled in the art will hereby also recognize that a single motor/drum or
winch can be used with
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the cables mounted in opposite directions and that as the drum/winch turns,
one cable is
unwound and the other cable is wound. In an embodiment, the control
mechanism(s) may
include a traction winch. By providing a displacement vessel 302 that is
capable of rotating in
the water to controllably adjust the drag force exerted on the drag panel 302,
the amount of
electricity generated by the generator may also be controllably adjusted.
[0065] The drag panel may be coupled to the displacement vessel such that
the drag
panel may swivel about an axis of the displacement vessel. In this instance,
the control cables
may be coupled to the drag panel to rotate the drag panel without rotating the
entire displacement
vessel. Alternatively, a control mechanism such as a motor may be coupled to
the axle on which
the drag panel is fixed to control the rotation of the drag panel. The
displacement vessel may
include multiple drag panels extending into the water from the bottom surface
of the
displacement vessel. In this instance, each drag panel may be fixed to an axle
such that the drag
panel may rotate. A control mechanism may be coupled to each axle to control
the rotation of
each individual drag panel.
[0066] FIG. 3B shows a displacement vessel 302 having a skin.
Displacement vessel 302
may include a structure or frame that is covered with a waterproof skin. The
skin may be made
of a metal, composite, polymer, or any other suitable material that can
withstand the ocean
environment and drag forces from the ebb and flow of water due to tidal
action. Displacement
vessel 302 further includes a drag panel 312 as described above with respect
to FIGS. 1A-1C.
Generally, an anchor cable 303 is connected to the drag panel 312 at both
sides of the drag panel
312. The location along the drag panel 312 where the anchor cable 303 is
connected may
correspond to a center of mass of the displacement vessel 302, such that when
a current causes
the displacement vessel 302 to drift, the displacement vessel 302 will remain
relatively stable in
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the water while maintaining a force on the anchor cable 303. The other end of
the anchor
cable 303 may be coupled to at least one directional converter and at least
one generator as
described above. The directional converter and the generator may be located on
land or on a
platform in the ocean.
[0067] FIG. 4A shows a displacement vessel 402 having a vertically
rotatable drag
panel 421. In particular, the rotatable drag panel 421 may be coupled to and
freely rotatable
about a vertical axis of the displacement vessel 402 via an axle 415. The axle
415 may be
coupled to a control mechanism 420, such as a motor, for example, that may be
configured to
control the angle of rotation of the drag panel 421.
[0068] FIG. 4B shows a displacement vessel 402 having multiple vertically
rotatable
drag panels 421a-421c. In particular, the rotatable drag panels 421a-421c may
be coupled to and
freely rotatable about respective vertical axes of the displacement vessel 402
via
axles 415a 415c. Each axle 415a-415c may be coupled to a respective control
mechanism
420a-420c, such as a motor, for example, that may be configured to control the
angle of rotation
of its respective drag panel 421a-421c. These configurations will function to
control, or assist in
controlling, the orientation of the displacement vessel, whether in
conjunction with one or more
control cables or independently of control cables.
[0069] FIGS. 5A-5C show an exemplary displacement vessel 502 having a
horizontally
rotatable drag panel 521. The displacement vessel 502 includes floatation
devices 560a
and 560b connected by transverse members 556a and 556b to create a frame from
which to hold
the drag panel 521 as the displacement vessel floats in the water. The
floatation devices 560a,
560b and transverse members 556a, 556b may be made from metal (e.g., steel,
stainless steel,
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titanium), polymer (e.g., polyethylene terephthalate, polypropylene,
polycarbonate, HDPE),
composite, or any other suitable material or combination of materials as is
known in the art.
While only two floatation devices 560a, 560b are shown, one skilled in the art
will understand
that any number of floatation devices may be used to maintain buoyancy of the
displacement
vessel 502 and to hold the weight of the drag panel 521 in the water. In an
embodiment, the
floatation devices 560a and 560b are pontoons. In another embodiment, the
floatation devices
560a and 560b may have a tubular or cylindrical shape.
[0070] The drag panel 521 extends from the displacement vessel 502 in a
generally
downwards direction (into the water) in order to capture drag forces caused by
the flow of water
due to tidal action or other currents. As the water current flows over the
surface of the drag
panel 521, the drag panel 521 acts as a "sail" to harness the force exerted by
the flow of the
water to move the displacement vessel 502 through the water. The drag panel
521 is rotatably
coupled to the floatation devices 560a and 560b along the horizontal axis 554
such that it may
freely rotate about the horizontal axis 554 from an active configuration (drag
panel in the water)
to a retracted configuration (drag panel out of the water). The horizontally
rotatable drag
panel 521 may be rotated about the horizontal axis by an angle with respect to
a horizontal axis.
The angle may be varied between 0 degrees and 180 degrees. In an example, when
the drag
panel is at 90 degrees with respect to the horizontal axis, the drag panel is
vertically extending
into the water. The angle may be decreased (e.g., by retracting the drag
panel) to adjust the
amount of drag force experienced by the drag panel 521. In another example,
when the direction
of water flow changes in the tidal cycle, the angle may be increased to adjust
the amount of drag
force experienced by the drag panel 521. In this arrangement, the drag panel
521 can be rotated
to a desired angle without having to change the orientation of the entire
displacement vessel 502.
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[0071] The drag panel 521 may be made of metal (e.g., steel, stainless
steel, titanium,
aluminum), polymer (e.g., polyethylene terephthalate, polypropylene,
polycarbonate,
polyethylene, high-density polyethylene), composite, or any other suitable
material or
combination of materials as is known in the art. The drag panel may have a
height that is
between 1 foot and 100 feet, a width between 1 foot and 200 feet, and a
thickness that is between
0.1 inch and 24 inches. One skilled in the art will recognize that the
displacement vessel and
drag panel may have any suitable dimensions to capture drag forces from the
ebb and flow of the
tide or other water currents. To minimize weight, the drag panel 521 may be
constructed of a
lightweight frame that is covered with a skin, such as sheet metal, polymer,
or composite, for
example. The drag panel 521 may be formed as two or more individual panels to
allow potential
for more variation in surface area facing the current or tide. The drag panel
521 may further
comprise any suitable shape on the surfaces facing the current to harness drag
forces. For
example, the drag panel 521 may include a concave shape on one or more
surfaces. In another
example, the drag panel may include a lofted cut shape.
[0072] The displacement vessel 502 further includes control mechanisms
520a and 520b
attached to floatation devices 560a and 560b configured to rotate the drag
panel 521. The
control mechanisms 520a and 520b may operate independently or together to
rotate the drag
panel 521 about a horizontal axis 554 of the displacement vessel 502. Any
suitable number of
control mechanisms may be used to rotate the drag panel 521. The control
mechanisms 520a
and 520b may include, for example, a winch, a motor, hydraulics, pneumatics,
or any other
suitable control mechanism as is known in the art. The control mechanisms 520a
and 520b may
be attached to the drag panel 521 at any suitable point. In some embodiments,
the drag
panel 521 may include arms 552a and 552b extending from the drag panel 521.
The arms 552a
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and 552b may extend at any suitable angle from a surface of the drag panel
and, preferably,
extend from the top surface of the drag panel. The arms 552a and 552b provide
a lever on which
the control mechanisms 520a and 520b provide force to rotate the drag panel
521 around the
points of attachment to the displacement vessel 502.
[0073] In an embodiment, material may be added to the drag panel 521 to
provide a
counterweight that assists the control mechanisms 520a, 520b in rotating the
drag panel 521.
The counterweight may be added to the front side or the back side of the drag
panel, depending
on which way the drag panel is intended to rotate. In the embodiment where the
drag panel
rotates back as shown in FIGS. 5A-5C and 6A-6C below, a counterweight may be
added on the
front side of the drag panel above the axis of rotation (i.e., the horizontal
axis 554).
[0074] As with the displacement vessels described above, displacement
vessel 502 may
include a bridle having control cables 528a and 528b configured to steer the
displacement vessel
502 through the water. The displacement vessel 502 may include any suitable
number of control
cables, such as two cables or four cables, for example. The control cables
528a and 528b extend
to an anchor cable 503 which connects the displacement vessel to a directional
converter at a
stationary location, such as land.
[0075] As shown in FIG. 5D, the drag panel 521 may include a frame having
one or more
vertically rotatable sub-panels 564a-564c. The vertically rotatable sub-panels
564a-564c are
similar to the drag panels 421 shown in FIGS. 4A and 4B and may be used to
reduce the force
necessary to retract the entire drag panel 521 about the horizontal axis. Each
vertically rotatable
subpanel 564a-564c is rotatable around a respective axle 515a-515c. Control
mechanisms may
be used, similar to the control mechanisms shown in FIGS. 4A and 4B, to
control the rotation of
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each respective sub-panel 564a-564c. In an example, before retracting the drag
panel 521, the
vertically rotatable sub-panels may be rotated (preferably by 90 degrees) and
then the entire drag
panel 521 may be retracted out of the water. Alternatively, the vertically
rotatable sub-panels
may be used for steering purposes or to adjust the amount of drag force
experienced by drag
panel 521 (and thus, electricity generated by the directional converter at the
stationary location).
[0076] FIGS. 6A-6C shows an exemplary displacement vessel 602 having a
horizontally
rotatable drag panel 621 in various positions. Similar to the displacement
vessels shown in
FIGS. 5A-5C, the displacement vessel 602 includes floatation devices 660a and
660b connected
via transverse members 656a and 656b. A drag panel 621 is attached to the two
floatation
devices 660a and 660b and is also coupled to control mechanisms 620a and 620b
via arms 652a
and 652b that extend from the drag panel 621. In FIGS. 6A and 6C, the arms
652a and 652b
extend at an angle from the drag panel 621. In an embodiment, the arms 652a,
652b may extend
from the drag panel 621 at any suitable angle, such as between 00 and 45 from
the vertical, for
example. Two control cables 628a and 628b are attached to the drag panel 621
and serve to
couple the displacement vessel 602 to an anchor cable (not shown) and a
directional converter
located at a stationary location, such as land. One skilled in the art will
recognize that any
suitable number of control cables (e.g., two, four, or eight) may be used to
control the orientation
of the displacement vessel 602.
[0077] In FIG. 6A, the drag panel 621 is fully vertical so that the
displacement vessel 602
will capture drag forces cause by the flow of water due to currents and/or
tidal action. In this
position, the drag panel 621 may capture a maximum amount of drag force from
the flow of
water than if the drag panel 621 were retracted at all. In FIG. 6B, the drag
panel 621 is partially
retracted by control mechanisms 620a and 620b. In FIG. 6C, the drag panel 621
is fully retracted
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by the control mechanisms 620a and 620b such that the drag panel 621 is
horizontal and
substantially out of the water.
[0078] FIG. 7A shows an exemplary retrieval mode with the drag panel 721
retracted.
Displacement vessels 702a-702c represent different scenarios of retrieval for
various angles
between the anchor cable and the stationary location when the displacement
vessel 702a-702c
has a fully retracted drag panel. Displacement vessel 702a has an angle of 200
between the
stationary location 706 and the anchor cable 703a, which is coupled to the
directional converter
709 at the stationary location 706, i.e., land. Displacement vessel 702b has
an angle of 30
between the stationary location 706 and the anchor cable 703b, which is
coupled to the
directional converter 709 at the stationary location 706, i.e., land.
Displacement vessel 702c has
an angle of 45 between the stationary location 706 and the anchor cable 703c,
which is coupled
to the directional converter 709 at the stationary location 706, i.e., land.
[0079] FIG. 7B shows an exemplary retrieval mode with the drag panel 721
fully
deployed. Similar to the displacement vessels 702a-702c shown in FIG. 7A,
displacement
vessels 702a-702c represent different scenarios of retrieval for various
angles between the anchor
cable and the stationary location when the displacement vessel 702a-702c has a
fully deployed
drag panel. Displacement vessel 702a has an angle of 20 between the
stationary location 706
and the anchor cable 703a, which is coupled to the directional converter 709
at the stationary
location 706, i.e., land. Displacement vessel 702b has an angle of 30 between
the stationary
location 706 and the anchor cable 703b, which is coupled to the directional
converter 709 at the
stationary location 706, i.e., land. Displacement vessel 702c has an angle of
45 between the
stationary location 706 and the anchor cable 703c, which is coupled to the
directional converter
709 at the stationary location 706, i.e., land.
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[0080] FIG. 8 shows an exemplary displacement vessel 802 having an array
of
directional converters 809a-809f and generators 816a-816f at a stationary
location 806. The
displacement vessel 802 may be similar to any of the displacement vessels
having a rotatable
drag panel as described in more detail above. In this instance, one
displacement vessel 802 is
coupled to a plurality of anchor cables 803a-803f and each anchor cable is
coupled to a
respective directional converter 809a-809f that is fixed at a stationary
location 806. As an
example, the stationary location 806 may be land, a barge, a pier, a platform
in the ocean
anchored to the ocean floor, or the ocean floor. In FIG. 8, the stationary
location is the shore
(land) adjacent the body of water in which the displacement vessel is located.
Moreover, after
consideration of the present disclosure, one of skill in the art will
recognize that the stationary
location may any suitable plot of land or on a mobile location, such as an
area further inland or
on a crane to provide, among other advantages, protection against flooding and
waves caused by
storms. The directional converters described herein can thus be positioned at
any suitable
stationary location such that one or more anchor cables can couple the
directional converter(s) to
one or more displacement vessels in the water.
[0081] Each of directional converters 809a-809f may be substantially
similar to the
directional converters described above. For example, each directional
converter 809a-809f may
include a drum 813a-813f around which the respective anchor cable 803a-803f is
wrapped.
Further, each directional converters 809a-809f may be independently engaged
(or disengaged)
with respect to the movement of the displacement vessel 802 to generate
electricity. As the ebb
and flow of tidal action causes the displacement vessel 802 to drift away from
the stationary
location 806, each anchor cable will exert a force on the respective drums
813a-813f, causing the
drums 813a-813f to rotate. The drums 813a-813f are fixed on axles 815a-815f
including drive
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gears 812a-812f, and the drive gears 812a-812f are coupled to gear boxes 814a-
814f, which may
be substantially similar to the gear box as described above. As the drums 813a-
813f rotate and
are engaged, the drive gears 812a-812f may rotate and transfer mechanical
power to the gear
boxes 814a-814f The engaged gear boxes 814a-814f may convert input RPM from
the drive
gears 812a-812f to a different RPM output to be transmitted to generators 816a-
816f The
engaged gear boxes 814a-814f are coupled to the generators 816a-816f, which
may be, for
example, fixed magnet generators as described above. The engaged gear boxes
814a-814f
transmit the mechanical power to the generators 816a-816f to produce
electrical power that may
be stored in a storage facility 824, which may include one or more batteries.
The electrical
power may be transmitted via a wire 804 to an electrical grid such that it may
be distributed to a
consumer to be consumed. When one directional converter is disengaged the
respective drum
may still rotate upon the movement of the displacement vessel and anchor
cable, but the drive
gears, gear boxes or generators may be positioned and disengaged such that no
electricity is
produced by that respective generator.
[0082] As the ebb and flow of tidal action causes the displacement vessel
802 to drift
back towards the stationary location 806, a control mechanism may reel in the
excess slack on
the anchor cables 803a-803f. The control mechanism may be substantially
similar to the control
mechanism described above. For example, the control mechanism may be a spring
or motor that
is coupled to the drums 813a-813f
[0083] Generally, each of the generators 816a-816f may have similar or
different
electrical output ratings. For example, each of generators 816a-816f may have
an electrical
output rating of 15kW at 125 RPM. In another embodiment, the electrical output
rating of the
generator may be between 1MW to 10MW at a speed between 5 RPM and 1600 RPM.
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Alternatively, each of generators may have different electrical output
ratings. For example, the
generators 816a-816f may have different electrical output ratings at lkW, 5kW,
10kW, 15kW,
20kW, and 25kW. In another example, the generators 816a-816f may have similar
electrical
output ratings of 15kW.
[0084] As a generator array, one or more generator(s) (or directional
converters) may be
engaged while other generators (or directional converters) may be disengaged.
In lower current
speeds, a smaller number of generators 816a-816f may be engaged to generate
electrical power
while in faster current speeds, more generators 816a-816f may be engaged to
produce electrical
power. Such an array permits one displacement vessel to generate an amount of
electricity that
is directly proportional to the tidal forces acting upon the displacement
vessel, and not limited to
the generating potential of a single generator. While Figure 8 shows six
generators coupled to
displacement vessel 802, this invention is not limited to this number of
generators, and any
suitable number of generators may be coupled to the displacement vessel,
depending on the size
of the displacement vessel, the expected strength of the tides and the
available area of the
stationary location.
[0085] FIG. 9 shows a graph of velocity of water current speed and drag
panel angle to
maintain a specified drag force. Throughout the tidal cycle, current velocity
may change. These
changes in current velocity may change the amount of electrical power
generated by the
displacement vessel as higher currents tend to generate more electrical power
than slow currents.
The drag panel 921 may be controllably retracted, i.e., rotated about the
horizontal, to maintain a
specified amount of drag on the drag panel to thus generate a steady amount of
electrical power
regardless of the water current speed. As shown in the graph, to maintain
480,000 lbs. of force D
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on the drag panel through current speeds of about 3.5 knots to about 11 knots,
the angle B
between the drag panel 921 and the vertical axis must be increased.
[0086] The present disclosure also provides for a method of generating
electricity using
the flow of water due to tidal action. The method includes releasing a
displacement vessel
having a drag panel rotatable about a horizontal axis of the displacement
vessel, wherein the drag
panel extends at an angle from a surface of the water. In an embodiment, the
drag panel may
extend vertically into the water. The method further includes generating
electricity as the
displacement vessel travels due to the flow of water. The method may further
include rotating
the drag panel such that the drag panel is substantially horizontal after
generating electricity.
The method may further include rewinding the displacement vessel after
rotating said drag panel.
[0087] The present disclosure also provides for a method of adjusting the
amount of drag
force experienced by a drag panel of a displacement vessel. The method
includes releasing the
displacement vessel in a body of water and rotating the drag panel by an angle
about a horizontal
axis of the displacement vessel to thereby adjust the amount of drag force
experienced by the
drag panel. In an embodiment, the angle is greater than 0 degrees and less
than or equal to 90
degrees. In another embodiment, the angle of the drag panel may be varied
between 0 degrees
and 180 degrees with respect to the horizontal axis. In an embodiment,
decreasing the angle
between the drag panel and the horizontal axis decreases the amount of drag
force experienced
by the drag panel. In an embodiment, increasing the angle between the drag
panel and the
horizontal axis increases the amount of drag force experienced by the drag
panel.
[0088] Variations and modifications will occur to those of skill in the
art after reviewing
this disclosure. The disclosed features may be implemented, in any combination
and
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subcombination (including multiple dependent combinations and
subcombinations), with one or
more other features described herein. The various features described or
illustrated above,
including any components thereof, may be combined or integrated in other
systems. Moreover,
certain features may be omitted or not implemented. Additionally, in any of
the embodiments
described above, the displacement vessel, directional converter(s), and
generator(s) may rely on
both lateral and vertical displacement due to both the rise/fall and ebb/flow
of tidal action.
[0089] Examples of changes, substitutions, and alterations are
ascertainable by one
skilled in the art and could be made without departing from the scope of the
invention disclosed
herein. All references cited herein are incorporated by reference in their
entirety and made part
of this application.
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