U.S. patent application number 16/453440 was filed with the patent office on 2019-10-24 for systems and methods for tidal energy conversion and electrical power generation.
The applicant listed for this patent is BIG MOON POWER, INC.. Invention is credited to Colin BAGLEY, Lynn BLODGETT.
Application Number | 20190323477 16/453440 |
Document ID | / |
Family ID | 56080452 |
Filed Date | 2019-10-24 |
View All Diagrams
United States Patent
Application |
20190323477 |
Kind Code |
A1 |
BLODGETT; Lynn ; et
al. |
October 24, 2019 |
SYSTEMS AND METHODS FOR TIDAL ENERGY CONVERSION AND ELECTRICAL
POWER GENERATION
Abstract
Assemblies systems, and methods are disclosed for generating
energy from natural forces and, more particularly, to energy
generation using tidal action. A tidal energy conversion assembly
includes a displacement vessel housing a directional converter that
is coupled to an electrical power generator. The tidal energy
conversion assembly further includes an anchor cable having a first
end, a second end connected to the directional converter, and a
length in between the first end and the second end. The anchor
cable may be threaded through an anchor at a stationary location,
such as a sea floor. The rising, falling, and/or drag forces of the
tide cause a change in the length of the anchor cable thus exerting
a force on the directional converter. The directional converter
converts this force into rotational energy that may be harnessed by
the electrical power generator to generate electricity for
consumption.
Inventors: |
BLODGETT; Lynn; (Salt Lake
City, UT) ; BAGLEY; Colin; (Salt Lake City,
UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BIG MOON POWER, INC. |
Salt Lake City |
UT |
US |
|
|
Family ID: |
56080452 |
Appl. No.: |
16/453440 |
Filed: |
June 26, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15143440 |
Apr 29, 2016 |
10378504 |
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16453440 |
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62322501 |
Apr 14, 2016 |
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62272759 |
Dec 30, 2015 |
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62261565 |
Dec 1, 2015 |
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62155538 |
May 1, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B63B 35/44 20130101;
Y02E 10/28 20130101; Y02E 10/30 20130101; Y02E 10/38 20130101; F05B
2240/93 20130101; B63B 2035/4466 20130101; B63B 21/50 20130101;
F03B 13/262 20130101; H02K 7/1853 20130101; Y02E 10/20
20130101 |
International
Class: |
F03B 13/26 20060101
F03B013/26; B63B 35/44 20060101 B63B035/44; H02K 7/18 20060101
H02K007/18 |
Claims
1-41. (canceled)
42. A method for generating electricity from the ebb and flow of
water due to tidal action, the method comprising: providing a
displacement vessel at a distance from a stationary location, said
displacement vessel operatively coupled to a plurality of
directional converters at the stationary location, wherein the
plurality of directional converters is coupled to a plurality of
electrical power generators; changing the distance between said
displacement vessel and said stationary location by tidal action;
engaging at least one of said plurality of electrical power
generators; converting the change in lateral distance of the body
into mechanical energy; transmitting the mechanical energy to the
at least one activated electrical power generator; and generating
electricity with the at least one activated electrical power
generator using the mechanical energy.
43. The method of claim 42, further comprising the step of engaging
an electrical power generator that was previously disengaged upon
the increases of the force of the tidal currents.
44. The method of claim 42, further comprising the step of
disengaging an electrical power generator that was previously
engaged upon the decrease of the force of the tidal currents.
45-57. (canceled)
58. A method for generating electricity from the ebb and flow of
water due to tidal action, the method comprising: changing a
distance between a body floating in the water and a stationary
location to a first lateral distance; generating electricity from
the changing of the first lateral distance; rotating the body about
an axis; changing distance between the body and the stationary
location to a second lateral distance; generating electricity from
the changing of the second lateral distance.
59. The method of claim 58, wherein rotating the body comprises:
winding a first control cable coupled to the body with a first
control mechanism; and releasing a second control cable coupled to
a body with a second control mechanism.
60-82. (canceled)
83. A method for generating electricity from the ebb and flow of
water due to tidal action, the method comprising: providing a
displacement vessel at a distance from a first stationary location,
said displacement vessel operatively coupled to a first directional
converter at the first stationary location and a second directional
converter at a second stationary location, wherein the first
directional converter is coupled to a first electrical power
generator and the second directional converter is coupled to a
second electrical power generator; changing the lateral distance
between said displacement vessel and said first stationary location
by tidal action in a first direction; engaging the first electrical
power generator to generate electricity; and changing the lateral
distance between said displacement vessel and said first stationary
location by tidal action in a second direction; and engaging at
least the second electrical power generator to generate
electricity.
84-96. (canceled)
97. A method for generating electricity using water flow in a
river, the method comprising: releasing a first displacement vessel
downstream in the river; generating electricity as the first
displacement vessel travels downstream in the river; releasing a
second displacement vessel downstream in the river; generating
electricity as the second displacement vessel travels downstream in
the river; and rewinding the first displacing vessel upstream as
the second displacement vessel travels downstream in the river.
98. The method of claim 97, further comprising rotating the first
displacement vessel before rewinding the first displacement
vessel.
99. (canceled)
100. A method for generating electricity from energy associated
with flowing water comprising: providing a displacement vessel in
an area of flowing water, wherein the displacement vessel includes
at least one drag panel extending downwardly therefrom; operatively
connecting the displacement vessel to a converter device for
translating movement of the displacement vessel in the water flow
into rotational energy which can actuate a generator; positioning
the displacement vessel in the flowing water with the water acting
against the at least one drag panel to cause movement of the
displacement vessel and thereby causing the converter device to
produce rotational energy for actuating one or more generators to
generate electricity.
101. The method according to claim 100, wherein the operative
connecting is carried out by an anchor cable secured at one end to
the displacement vessel and its other end wrapped around a
directional converter, such that movement of the displacement
vessel causes the directional converter to produce rotational
energy for actuating the one or more generators.
102. The method according to claim 101, which further includes
locating a said directional converter and the at least one
generator at a stationary location.
103. The method according to claim 102, which further includes
passing the anchor cable through an anchor member fixed in place
relative to the flowing water.
104. The method according to claim 102, wherein the stationary
location is land.
105. The method according to claim 100, wherein the actuating of
the one or more generators includes selectively engaging and
disengaging the one or more generators in accordance with
predetermined criteria.
106. The method according to claim 101, further comprising
selectively changing the orientation of the displacement vessel at
least in lateral directions in accordance with predetermined
criteria.
107. The method according to claim 101, further comprising
selectively changing the orientation of the displacement vessel at
least in vertical directions in accordance with predetermined
criteria.
108. The method according to claim 100, wherein the flowing water
is a tidal water flow.
109. The method according to claim 100, wherein the flowing water
is a river current.
110-133. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/143,440, filed on Apr. 29, 2016, which
claims the benefit of priority under 35 U.S.C. 119(e) to U.S.
Provisional Patent Application No. 62/322,501, filed on Apr. 4,
2016, U.S. Provisional Patent Application No. 62/272,759, filed on
Dec. 30, 2015, U.S. Provisional Patent Application No. 62/261,565,
filed on Dec. 1, 2015, and U.S. Provisional Patent Application No.
62/155,538, filed on May 1, 2015, each of which is hereby
incorporated by reference in its respective entirety.
FIELD OF THE INVENTION
[0002] 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. In particular, the present
disclosure illustrates a system and method for converting potential
and kinetic energy from ocean tidal movements--from either or both
of the vertical rise and fall and/or 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. In addition, the disclosure describes a novel method for
manufacturing a displacement vessel that can be utilized in the
tidal energy conversion system according to the invention.
BACKGROUND
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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 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.
[0008] 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. Pat. Nos. 5,426,332, 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. Pat. No. 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.
[0009] A need therefore exists for an efficient and cost-effective
energy conversion/electrical power generation system that can
harness the potential and kinetic energy of tidal action as the
water level rises and falls and/or as the water ebbs and flows due
to changing tidal action and produce electrical power for
subsequent consumption.
SUMMARY OF THE INVENTION
[0010] Disclosed herein is a novel tidal energy conversion assembly
and method for generating electricity. In one aspect, a tidal
energy conversion assembly of the invention captures energy from
the rising and/or falling of the tide. In particular, the tidal
energy generation assembly may utilize a buoyant displacement
vessel anchored to a stationary location (e.g., bay or ocean floor,
on land, or a crane). The displacement vessel may house or may be
attached to a directional converter operatively coupled to a
generator for producing electrical power as a result of translating
the energy released by the vertical rise/fall of the tide and/or by
the change in distance from the stationary location into rotational
energy applied to the generator for producing electrical power. The
displacement vessel may be any structure that maintains buoyancy in
water, and thus rises or falls generally vertically with the tides,
and/or drifts laterally due to drag forces caused by the ebb and
flow of water during tidal action or other currents. The
displacement vessel may be anchored or tethered to the bay or ocean
floor or land by at least one anchor cable which is operatively
coupled to the directional converter for translating the vertical
movement of the displacement vessel to rotational movement which
can be used to operate a generator and produce electric power.
[0011] The directional converter may be housed on the displacement
vessel or located away from the displacement vessel. 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. Thus, as the displacement
vessel rises with an incoming tide, the anchor cable begins to
unwind, causing the drum to rotate such that the directional
converter converts the vertical movement of the displacement vessel
into mechanical energy (e.g., rotational kinetic energy) which in
turn powers the generator to produce electrical energy. In the
reverse direction, as the displacement vessel falls with the
falling tide, an optional stationary frame may be positioned above
the displacement vessel and coupled with a cable or other
attachment to the directional converter to capture the change in
potential energy in the opposite direction due to the falling of
the displacement vessel. The stationary frame is generally immobile
with respect to the water movements, and, as the displacement
vessel falls with the tide, the displacement vessel pulls upon the
cable attached to the frame, and the cable causes the direction
converter to turn and capture energy.
[0012] 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. Because
the change in height between the bay/ocean floor and the water
surface due to the tide occurs at a relatively slow rate (e.g.,
even only about 1.8 in/min in the Bay of Fundy which has the
largest tidal change in the world), rotation of the drum, and thus
the gearing mechanism, due to this change in height may also be
relatively slow. The electric generator, however, 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.
[0013] 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. In an alternative embodiment, a rack and
pinion mechanism can be used to capture energy from the rising and
falling of the tide.
[0014] 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.
[0015] In another aspect of the invention, the invention comprises
a method of generating electricity from tidal actions. The method
according to the invention involves converting vertical motion
caused by rising and falling tidal action into rotational energy
and transferring the resulting rotational energy to operate an
electrical power generator for producing electricity. As the tide
rises and/or falls, a vertical distance between the surface of the
water and the stationary location will change. This vertical change
in distance may be converted into rotational energy that is used to
energize the electrical power generator to generate electricity. In
a particular embodiment, a method of the invention comprises the
steps of: allowing the tidal action to change a vertical distance
between a body at the water surface and a stationary location below
the body, wherein the change in vertical distance is defined from a
first distance above the stationary location to a second distance
above the stationary location; converting the change in vertical
distance of the body into mechanical energy; transmitting the
mechanical energy to an electrical power generator; and generating
electricity with the generator using the mechanical energy. The
mechanical energy may be rotational kinetic energy.
[0016] The stationary location may be a bay/ocean floor. The body
may be a displacement vessel housing a directional converter
coupled to a generator and the displacement vessel may be disposed
at the first distance from the stationary location. The method may
further include providing an anchor cable having a first end and a
second end, whereby the second end is attached to the directional
converter and the anchor cable extends to an anchor secured at the
stationary location. The anchor cable has a first length between
the directional converter and the anchor. The second distance may
be greater than the first distance, and the change in vertical
distance may activate the directional converter. The method may
further include storing at least a portion of the mechanical energy
as potential energy with a storage mechanism; allowing the tidal
action to change the vertical distance between the displacement
vessel and the stationary location to a third distance, wherein the
third distance is less than the second distance; releasing the
stored mechanical energy from the storage mechanism; transmitting
the stored mechanical energy to the generator; and generating
electricity with the stored mechanical energy. The storage
mechanism may be a spring.
[0017] In another aspect of the invention, the tidal energy
conversion assembly may generate energy utilizing drift/drag forces
from the ebb and flow of the tide and/or currents. In this
arrangement, the tidal energy conversion assembly may include a
displacement vessel and directional converter that is substantially
similar to the displacement vessels described above. The
displacement vessel may generally be anchored to the stationary
location by at least one anchor cable that is operatively coupled
to a rotatable drum on the directional converter which is in turn
operatively coupled to the generator essentially as described
above. 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. As
described above, the assembly may include a gear multiplication
arrangement, if desired, to increase the speed (or RPM) of the
output applied to the generator.
[0018] Thus, as the ebb and flow of the tide, or other currents of
the ocean, causes the displacement vessel to drift in a generally
lateral direction relative to the stationary location, there may be
greater potential for electrical power generation because the
lateral drift may provide a significantly greater length of travel
for the anchor cable and thereby more rotational energy
transferrable to the generator. 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. Of course, it will be understood in view of the foregoing
that the vertical and lateral concepts described herein can be
combined to potentially maximize the amount of electrical power
generation.
[0019] In an embodiment of the invention, a system configured to
capture drag forces is described, wherein the displacement vessel
includes a drag panel extending from an external surface of the
displacement vessel. The drag panel may increase 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. In some embodiments,
the height of the drag panel may be 5 ft, although one of skill
will recognize that the drag panel may have any suitable height to
capture additional drag forces. 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.
[0020] In an aspect of the invention, a 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. 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.
[0021] In another embodiment, 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.
[0022] The bridle--i.e., a 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 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. In another
embodiment, 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 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.
[0023] In another embodiment, the directional converter(s) and
generator(s) may be located on a stationary location in the water.
The stationary location may comprise, for example, a barge (such as
a work barge or spud barge) floating or fixed in the water. In a
particularly useful embodiment, one or more directional converters
may be mounted on the barge. The directional converter(s) may
comprise any of the directional converters described herein. One or
more anchor cables may extend from the directional converter(s),
through a pivot frame to direct the anchor cable into the water,
and out to a displacement vessel in the water. The anchor cable may
further comprise a tensiometer to record/transmit data to an
operator regarding the forces exerted on the anchor cable from the
displacement vessel during operation. The displacement vessel may
comprise any of the displacement vessels described herein and may
be configured to capture energy from the rise/fall of the water due
to tidal action and/or drag forces from water flow due to tidal
action or other currents. The barge may further comprise a
hydraulic power mechanism to provide power to any components of the
directional converter which may require hydraulic power, such as,
for example, a reverse motor or winch.
[0024] In another aspect, a method according to the invention
involves converting into energy the lateral motion caused by the
ebb and flow of water due to tidal action. The ebb and flow of the
water due to tidal action causes a body in the bay/ocean to drift
laterally and change its position with respect to a fixed location
at the stationary location. In accordance with the principles
described above, this change in lateral distance may be converted
into rotational energy that is used to energize the electrical
power generator to generate electricity. This method to produce
electricity from the lateral ebb and flow of water due to tidal
action may include the steps of: allowing the tidal action to
change a lateral distance between a body floating in the water and
a stationary location below the body; converting the change in
lateral distance of the body into mechanical energy; transmitting
the mechanical energy to an electrical power generator; and
generating electricity with the generator using the mechanical
energy. The mechanical energy may be rotational kinetic energy. The
stationary location may be a bay/ocean floor. The body may be a
displacement vessel housing a directional converter coupled to a
generator, and the displacement vessel may be disposed directly
above the stationary location. The method may further include
providing an anchor cable having a first end and a second end,
whereby the second end is attached to said directional converter
and the anchor cable extends to an anchor secured at said
stationary location. The anchor cable may have a first length
between said directional converter and said anchor.
[0025] In yet another embodiment, a tidal energy generation
assembly may include a turbine mounted within a drag panel of a
displacement vessel and a directional converter mounted on the
displacement vessel. The displacement vessel may be connected to a
stationary location, such as land or a spud barge, for example, by
control cables coupled to an anchor cable. One or more rewind
assemblies may be housed at the stationary location to control the
winding of an anchor cable and alter (i.e., increase or decrease)
the distance of the displacement vessel from the stationary
location. The displacement vessel may also include a power cable
extending from the displacement vessel to the stationary location
to transmit electrical power to/from the displacement vessel. Each
control cable may be coupled to a respective control mechanism that
may be housed within or mounted on the displacement vessel. The
control mechanisms may independently control the winding/unwinding
of the respective control cables to effectuate steering of the
displacement vessel in the water. The control mechanisms may
wind/unwind their respective control cable to adjust the
orientation of the displacement vessel with respect to the
water/current flow, e.g., by adjusting the yaw, pitch, and/or roll
of the displacement vessel. For example, the yaw of the
displacement vessel may be adjusted using the control cables to
rotate the displacement vessel in a clockwise direction in the
water.
[0026] The control mechanisms may also be used to control the
amount of electricity generated. For example, by rotating the
displacement vessel to an angle away from the direction of water
flow, less drag force may be exerted on the drag panel (and the
turbine) thus reducing the amount of electricity generated by the
electrical power generator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The foregoing and other objects and advantages will be
apparent upon consideration of the following detailed description,
taken in conjunction with the accompanying 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.
[0028] FIG. 1A shows a cross-section of a tidal energy conversion
assembly in accordance with an implementation of the
disclosure.
[0029] FIG. 1B shows a tidal energy conversion assembly after the
tide has risen.
[0030] FIG. 1C shows an enlarged view of a directional converter of
a tidal energy conversion assembly.
[0031] FIG. 1D shows an enlarged view of an alternative embodiment
of a directional converter having a rack and pinion mechanism.
[0032] FIG. 1E shows general implementation of a rack and pinion
mechanism for capturing energy from the rising and falling of the
tide.
[0033] FIG. 2 shows a tidal energy conversion assembly having a
cylindrical displacement vessel.
[0034] FIG. 3 shows a system of multiple tidal energy conversion
assemblies.
[0035] FIG. 4 shows a tidal energy conversion assembly with a
displacement vessel having multiple chambers.
[0036] FIGS. 5A-5C show a tidal energy conversion assembly having a
directional converter comprising a drag energy converter.
[0037] FIG. 5D shows an enlarged view of a directional converter
comprising a drag energy converter.
[0038] FIG. 6A shows a directional converter comprising a drag
energy converter.
[0039] FIG. 6B shows a displacement vessel frame.
[0040] FIG. 6C shows a displacement vessel having a skin.
[0041] FIG. 7 shows a displacement vessel that is itself a drag
panel.
[0042] FIG. 8 shows a displacement vessel having an array of
directional converters and generators on land.
[0043] FIG. 9 shows a displacement vessel having an array of
directional converters on land and a pulley arrangement.
[0044] FIG. 10 shows a bottom view of a displacement vessel,
according to another aspect of the invention.
[0045] FIG. 11A shows an isometric front view of a displacement
vessel, according to the aspect described with respect to FIG.
10.
[0046] FIG. 11B shows a bottom view of a displacement vessel prior
to a rotation, according to the aspect described with respect to
FIG. 10.
[0047] FIG. 11C shows a bottom view of a displacement vessel during
a rotation, according to the aspect described with respect to FIG.
10.
[0048] FIG. 11D shows a bottom view of a displacement vessel after
a rotation, according to the aspect described with respect to FIG.
10.
[0049] FIG. 11E shows a side view of a displacement vessel,
according to the aspect described with respect to FIG. 10.
[0050] FIG. 12A shows a back view of a displacement vessel.
[0051] FIG. 12B shows a top view of a displacement vessel.
[0052] FIG. 12C shows a side view of a displacement vessel.
[0053] FIGS. 13A and 13B show a rendering of a displacement having
a drag panel with a parabolic shape.
[0054] FIGS. 14A and 14B show a rendering of a displacement vessel
having a drag panel with an alternate surface shape.
[0055] FIG. 15A shows a top view of a layout for a tidal energy
generation system comprising a directional converter positioned on
a barge.
[0056] FIG. 15B shows a side view of a layout for a tidal energy
generation system comprising a directional converter positioned on
a barge.
[0057] FIG. 15C shows a side view of a layout for a tidal energy
generation system comprising a directional converter positioned on
a barge.
[0058] FIGS. 16A and 16B show a rendering of a crane system
comprising a directional converter positioned at the base of a
crane.
[0059] FIG. 17 illustrates a tidal energy generation assembly
including a turbine coupled to a directional converter.
[0060] FIG. 18 illustrates a tidal energy generation assembly
including a turbine mounted within a drag panel and a directional
converter.
[0061] FIG. 19 illustrates a tidal energy generation assembly
including a turbine directly mounted to the bottom of a
displacement vessel.
[0062] FIG. 20A shows an isometric view of an exemplary
displacement vessel.
[0063] FIG. 20B shows a side view of an exemplary displacement
vessel.
[0064] FIG. 21A shows a tidal energy generation system configured
to capture river currents.
[0065] FIG. 21B shows a tidal energy generation system configured
to capture river currents.
[0066] FIG. 22 shows a tidal energy generation system configured to
capture drag in two directions of water flow.
[0067] FIG. 23A shows a displacement vessel having a rotatable drag
panel.
[0068] FIG. 23B shows a displacement vessel having multiple
rotatable drag panels.
DETAILED DESCRIPTION OF THE INVENTION
[0069] To provide an overall understanding of the systems, devices,
assemblies, and methods described herein, certain illustrative
embodiments will be described. For the purpose of clarity and
illustration, these systems and methods will be described with
respect to tidal energy conversion assemblies for generating
electrical energy. It will be understood by one of ordinary skill
in the art that the systems, devices and methods described herein
may be adapted and modified as is appropriate, and that these
systems, devices and methods may be employed in other suitable
applications, such as for other types of energy conversion devices,
and that other such additions and modifications will not depart
from the scope of invention and claims hereof.
[0070] A tidal electrical energy generation assembly of the present
invention utilizes the vertical rising/falling of tidal action,
and/or the lateral drift due to drag forces caused by the ebb and
flow of water during tidal action to generate energy. According to
one basic concept of the invention, the tidal energy conversion
assembly is secured or tethered by an anchor cable to a stationary
location, which may be, for example, a bay/ocean floor (sometimes
referred to generally as a seabed), on a crane, or on shore, or on
a barge, platform, or pier secured to the sea floor, to float
upwardly and downwardly with the rising and falling tides. In
general, the tidal energy conversion assembly comprises at least
one anchor cable connecting a displacement vessel to a stationary
location, and the anchor cable may be secured at the stationary
location. The movement of the assembly resulting from the tidal
actions relative to the stationary location causes the anchor cable
to exert a force upon the assembly, which force may be converted
into mechanical energy through a conversion mechanism which then
transmits the mechanical energy to a generator which produces
electricity for storage and/or consumption. Except as set forth
below in FIGS. 17-19, the tidal energy generation system does not
include a turbine. In another aspect of the invention, the tidal
energy generation assembly generates electrical energy primarily as
a result of the lateral movement, or drift, of the assembly
relative to a stationary location due to the ebb and flow of the
water during tidal action. To increase the generation of electric
power, the tidal energy conversion system of the invention may
comprise a plurality of the tidal energy conversion assemblies as
described herein.
[0071] The displacement vessel is a structure that is capable of
floating at a distance above or away from a stationary location,
e.g., a bay/ocean floor or a fixed barge or platform elevated from
the bay/ocean floor (described in more detail below), or on shore,
or on a crane, such that the displacement vessel changes its
distance to the stationary location as the tide rises and falls or
is capable of being dragged laterally by the ebb and flow of water
during tidal action (or both). Exemplary, but non-limiting,
dimensions for height, width, and length of a displacement vessel
or barge may range between 1 m and 100 m, with a volume ranging
between 1 m.sup.3 and 1,000,000 m.sup.3. The displacement vessel
may be manufactured using materials such as polymer (e.g.,
polyethylene terephthalate), concrete, cement, fiberglass, pumice,
steel, amorphous metal alloys, or other suitable materials. At
least one anchor cable connects the displacement vessel to the
stationary location. The anchor cable is also operatively connected
to a directional converter supported by the displacement vessel.
The vertical rise and fall of the tide, and/or lateral drift due to
drag forces caused by the ebb and flow of water during tidal
action, causes the displacement vessel to move relative to the
stationary location, and thus changing the length of the anchor
cable between the displacement vessel and the stationary location.
Such movement in the position of the displacement vessel relative
to the stationary location causes the anchor cables to exert a
force on the directional converter and transmit that force to a
generator for producing electrical energy.
[0072] The displacement vessel may be anchored by at least one
anchor cable to a stationary location, for example, the sea floor,
land, or a submerged or fixed platform. Each anchor cable may be
attached to the same or different anchors at the same or different
stationary locations to secure the displacement vessel. Anchor
cables may be made of braided steel, composite, fiber, nylon,
amorphous metal alloys, or any other suitable material to secure
the displacement vessel and withstand the sea environment. Each
anchor cable may have a diameter in the range of 0.1 inch to 8
inches and the anchor cables may each have lengths in the range of
50 ft to 150,000 ft. The skilled person will understand that the
diameter of an anchor cable should be large enough to withstand the
force of the displacement vessel pulling axially on the anchor
cable. For example, if a single anchor cable is used to anchor the
displacement vessel, a larger diameter cable may be required to
withstand the pulling force of the displacement vessel moves
vertically with the rising and falling of the tide or moves
horizontally from the ebb and flow of tidal action. Nevertheless,
the skilled person will recognize the appropriate length and
diameter needed for such anchor cables.
[0073] Where a submerged or fixed floating platform is used as a
stationary location, the platform may include a substantially solid
structure or frame that is elevated above the bay/ocean floor by a
fixed distance or elevation. The platform may be elevated by, for
example, a truss structure that is secured to the seabed or by one
or more anchor cables similar to the anchor cables described above.
If the platform is connected to the bay/ocean floor by one or more
anchor cables, the platform may further include one or more
buoyancy chambers to provide buoyant forces that allow the platform
to float above the bay/ocean floor. These chambers may be
substantially similar to the chambers described below with respect
to FIG. 4.
[0074] The displacement vessel houses, supports, or is attached to
a directional converter operatively coupled to at least one anchor
cable and a generator. As used herein, a directional converter is a
device that converts motion or forces in one direction to motion or
forces in another direction. For example, a directional converter
may convert generally linear (e.g., vertical) motion of a member
into rotational motion of an axle, using, for example, a drum. The
directional converter may include hydraulic actuators, such as a
hydraulic motor coupled to the drum, for example, to provide
rotational power to reel in the anchor cable. The directional
converter may comprise a drive cable connected to at least one
anchor cable and a drive gear that couples the drive cable and the
generator. Upon the vertical rising/falling of the displacement
vessel with the rising/falling tide, a change in the position of
the displacement vessel relative to the stationary location causes
the anchor cable to exert a force upon the direction converter
(such as by a cable wrapped around a drum on the directional
converter or a rack and pinion gear arrangement), which, in turn,
converts the force or motion into, for example, a rotational force
which is then transmitted to a generator for producing electrical
power. In an embodiment having a rack and pinion or like mechanism,
energy can be produced with both the rising and falling of the
tide.
[0075] As a non-limiting example, the generator may be a fixed
magnet (or permanent magnet) generator. A fixed magnet generator
includes a permanent magnet fixed to a shaft, and the rotation of
the permanent magnet induces an electric current in a stationary
armature within the generator. The armature includes one or more
metal wires/coils within the magnetic field of the permanent magnet
such that the rotation of the magnet induces an electrical current
in the wires thus generating electrical power. The generated
electrical power may be transmitted to a storage facility or
directly to consumers for consumption. A fixed magnet generator may
be suitable for generating electrical power using a lower
rotational speed of an axle, such as a rotational speed under 1000
RPM, for example. Because a fixed magnet generator may produce
electrical power at lower rotational speeds than traditional
electric generators, a direct drive approach may be used to
operatively couple the directional converter to the generator. A
direct drive approach involves coupling the directional converter
directly to the generator via a chain, for example, without the use
of gearing mechanisms or gear boxes to convert the RPM of the
directional converter into a different RPM input for the generator.
In one example, an axle on which the drum is fixed may include a
gear that is operatively coupled by a chain to a gear on an axle of
the fixed magnet generator. As the drum turns, thus causing the
axle on which the drum is fixed to also turn, the chain will
transfer rotational power directly to the axle of the fixed magnet
generator, causing the permanent magnet to rotate and induce an
electric current within the armature to produce electrical power
for storage or consumption. A fixed magnet generator may have an
output in the range of 1 kW to 1 MW or more (as a potentially
practical embodiment, a 5-6 MW generator can be used), although one
of skill in the art will recognize that any suitable generator may
be used to convert the rising and falling of the tide and/or ebb
and flow of the water due to tidal action into electrical power. An
example generator that may be used with the present invention is a
Ginlong Technologies GL-PMG-15K generator rated for 15 kW at 125
RPM. In a particularly practical embodiment, a 100 kW generator may
be used with the present invention in addition, or alternatively,
to the generators described herein. Other exemplary generators that
are within the scope of the invention are discussed in Generators,
a 2014 G E Power Conversion Product Catalogue.
[0076] The displacement vessel may further include a drag energy
converter as a directional converter, where the drag energy
converter is capable of being engaged by at least one anchor cable
or drive cable and coupled to a generator. When the tide changes,
tidal currents due to the ebb and flow of water during tidal action
may drag the displacement vessel laterally with respect to an
initial starting point (as well as rise or fall with the tide).
Other ocean currents, such as those caused by the wind or thermal
differences in the water, may further contribute to the lateral
drag of the displacement vessel. In one embodiment, the drag energy
converter may comprise a spindle or rotatable drum that is
connected to a generator by a gearing mechanism, where at least one
anchor cable is wound around the drum. As the currents caused by
the ebb and flow of water during tidal action drag the displacement
vessel laterally from the initial starting point, the lateral
movement of the displacement vessel will cause the anchor cable to
exert tension forces on the drum, and the drum will rotate. As the
drum rotates, the rotational kinetic energy of the drum is
transferred via a gearing mechanism to the generator, such that the
rotational kinetic energy may be converted into electrical energy
to be consumed or stored as desired. As the tide changes again and
the displacement vessel moves laterally in a (generally opposite)
different direction with respect to the stationary location, any
slack on the anchor cable may be wound back into the drum by any
conventional mechanism, for example, by a motor or spring.
[0077] In another embodiment, the directional converter may include
a plurality of drums and a plurality of cables to utilize lateral
motion in multiple directions to generate electricity (to be
further discussed below). For example, two drums--each attached to
at least one anchor cable--may be disposed on the displacement
vessel or at different points on shore or a mix of both such that
as the displacement vessel moves laterally in a first direction, a
first anchor cable unwinds from a first drum causing the first drum
to rotate. This rotation of the first drum is transferred to the
electrical power generator to generates electricity as the
displacement vessel moves in the first lateral direction. When
moving in the first lateral direction, the second anchor cable may
gain slack. The directional converter may include a control
mechanism (for example, a spring or a motor) to reel the second
anchor cable back around a second drum. 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.
[0078] As the displacement vessel moves laterally in a second
direction, the second anchor cable may be 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. 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 cable may
be reeled back into the second drum when the displacement vessel
moves again in the first direction. Thus, electric power can be
generated during both general directions of travel. In accordance
with these concepts, further drums may be utilized to capture
energy if the displacement vessel moves laterally in other
directions.
[0079] The displacement vessel may further include a drag panel
extending from an external surface of the displacement vessel. The
drag panel may increase the surface area on which drag forces act
due to the ebb and flow of water caused by tidal action (or drag
forces caused by other ocean currents), allowing the displacement
vessel to be more effectively moved laterally by the ebb and flow
of water. The drag panel may extend in a generally downwards
direction from the external surface of the displacement vessel. The
drag panel may have a height that is between 1 ft and 100 ft. In
some embodiments, the height of the drag panel may be 5 ft,
although one of skill will recognize that the drag panel may have
any suitable height to capture additional drag forces. 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. The drag panel may have a substantially
similar width to that of the displacement vessel, or the drag panel
may be narrower than the width of the displacement vessel. The drag
panel may be manufactured out of any suitable material, such as
those discussed above with respect to the displacement vessel. The
drag panel may have a flat shape, or include one or more non-flat
sides configured to capture drag forces. In an example, the sides
of the drag panel may include a parabolic shape, a concave shape,
or a lofted cut.
[0080] In general, the drag panel may be fabricated of one or more
materials suitable to withstand the drag forces from the ebb and
flow of tidal action and/or other currents. In an example, the drag
panel may be fabricated from an extruded metal sheet or panel.
[0081] The displacement vessel may include a control mechanism such
that the control mechanism may deploy and retract the drag panel
from the displacement vessel. For example, the drag panel may be
stored within the displacement vessel in a first position. The
control mechanism may controllably deploy the drag panel at a
specified time to a second position, such as a time when strong
current conditions exist. If the drag panel is not needed, the
control mechanism may retract the drag panel back into the
displacement vessel. The control mechanism may include hydraulics
or an electric motor that may be powered by the energy generated by
the displacement vessel.
[0082] The displacement vessel may further include a control
mechanism to control the surface area of the drag panel. The drag
panels may also include "windows" of any appropriate size within
said drag panels that may be controllably opened or closed to
adjust the desired drag force upon the displacement vessel. Such
windows may be fabricated by cutting one or more openings in the
drag panel, and fastening a second panel parallel to said window
that can slidably close said window. For example, a hydraulic ram
may open and close windows (or through-holes) in the drag panel to
change the surface area on which the tidal currents interact. Upon
activation, the hydraulic ram may translate a plate over a window
or through-hole in the drag panel to increase the surface area of
the drag panel and thus increase the drag experienced by the
displacement vessel. Additionally, the hydraulic ram may retract
the plate from the window or through hole in the drag panel to
reduce the surface area of the drag panel and thus decrease the
drag experienced by the displacement vessel.
[0083] The displacement vessel may further include a depth control
mechanism to allow the displacement vessel to controllably change
its operating depth in the water, such that it may operate at a
"safe" depth to avoid objects in the water such as keels,
propellers, and rudders of boats or other devices located in the
water. In one example, the depth control mechanism may include one
or more ballast tanks within the displacement vessel. The ballast
tanks may be filled with water when the displacement vessel needs
to increase its depth. To decrease its depth or surface, the
ballast tanks may release or pump out water using a pump, for
example. In another example, the depth control mechanism may
include one or more horizontal or vertical planes to steer or pitch
the displacement vessel towards the bay/ocean floor or towards the
water surface. The one or more planes may be affixed to any
suitable location on the displacement vessel, such as the side
panels of the displacement vessel, for example. The horizontal
planes may be rotated about an axis while connected to the
displacement vessel, so as to change the pitch angle of the
displacement vessel and increase or decrease its depth as the
displacement vessel moves through the water. The depth control
mechanism may allow the displacement vessel to controllably
submerge at a specified time and resurface at a later time. The
achieved depth for the displacement vessel may vary from the water
surface to more than 100 feet below the surface.
[0084] The tidal energy generation assembly may include a
displacement vessel that is rotatable. As described above, the
displacement vessel is coupled by an anchor cable to a directional
converter positioned at a stationary location. 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.
[0085] 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 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. In another embodiment, 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.
[0086] 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
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.
[0087] Optionally, the displacement vessel may further include at
least one arm coupled to and extending away from the displacement
vessel. The arm(s) may be used to house and protect the control
cable extending from the displacement vessel to the anchor cable,
as described above. As the control cable within the arm lengthens
or shortens, thereby rotating the displacement vessel, the arm may
pivot and change the angle at which it extends from the
displacement vessel and thereby not interfere with rotation of the
displacement vessel as the control cable(s) lengthen or shorten.
The arms may thus be made of any suitable material for effectuating
the function of the cable without interference. For example, the
arms may comprise a polymer, such as a polyurethane foam.
[0088] The control cables allow the displacement vessel to rotate
about a vertical axis and thus adjust (capturing or reducing) the
amount of drag forces exerted on the drag panel from the flow of
water in various directions, and thereby also control the amount of
electricity generated. As the displacement vessel is rotated, any
drag panel on the displacement vessel also rotates, thereby
controllably adjusting the surface area of the drag panel exposed
to the force of water. For example, if the displacement vessel is
rotated from an orientation that is perpendicular to the flow of
water to an orientation that is at an acute angle relative to the
perpendicular, less force from the flow of water may be exerted on
the drag panel. Thus, less force will be transmitted to the
directional converter and less energy will ultimately be generated
by the generator.
[0089] In operation, the displacement vessel is positioned in the
water such that one side of the drag panel captures drag forces
resulting from the pressure exerted on the drag panel as a result
of the water flow against the drag panel. To effect rotation of the
displacement vessel, a first control mechanism may wind or release
a first control cable such that one side of the displacement vessel
changes its distance relative to the anchor cable. Where the
displacement vessel has multiple control cables, a first control
mechanism may wind (or release) a first control cable while a
second control mechanism releases (or winds) a second control
cable, again allowing the displacement vessel to change its
orientation relative to the anchor cable. Such control cables may
be housed within arms, which swing about the displacement vessel as
the displacement vessel rotates in the water due to the lengthening
or shortening of the control cables. When the displacement vessel
is perpendicular to the flow of water, it experiences a maximum
amount of drag force. Upon rotation of the displacement vessel to
an angle away from perpendicular, the drag panel may experience
less drag force, thus allowing the amount of drag force exerted on
the displacement vessel to be controllably adjusted.
[0090] In another aspect of the invention, the displacement vessels
described herein may be replaced with other suitable mechanisms for
capturing the ebb and flow of water due to tidal action and/or
other current flows. Such mechanisms may include a turbine having
one or more propellers, rotors, or impellors. Alternatively, an
array of turbines having one of the previously described
constructions may be used in place of the displacement vessel. In
this approach, the system enjoys the benefit of turbine rotation
caused by tidal flow and/or other currents as well as the
land-based generator location as described above.
[0091] In any case, the turbine(s) may be anchored to or attached
to the ocean/bay floor or may be floating at or near the water
surface via a floatation device as described above. The turbine may
be coupled to a drum that is under water (or alternatively above
water in the case that the turbine is floating at the surface of
the water) via a coupling mechanism that may be, for example, a
chain or cable. As water flows past the turbine, the turbine
rotates, causing the drum to rotate and wind or unwind the anchor
cable. The anchor cable may extend along the ocean/bay floor and be
coupled to a directional converter that is stationed on land. The
directional converter may be substantially similar to the
directional converters described herein and thus converts
mechanical energy transferred from the anchor cable to the
directional converter into electrical energy to be stored and/or
consumed.
[0092] Energy Generation Using Rising/Falling of the Tide
[0093] In one basic aspect of the present invention, the tidal
energy conversion assembly utilizes the vertical rising/falling of
the tides to generate electricity. The tidal energy conversion
assembly includes a displacement vessel that is anchored to a
stationary location, such as stationary location, via at least one
anchor cable. As the tide rises and falls, the distance between the
stationary location and the displacement vessel changes, causing a
force to be exerted on a directional converter supported on the
displacement vessel (as further discussed below). The directional
converter converts this force into mechanical energy (e.g.,
rotational energy), and that mechanical energy is transmitted to an
electrical power generator for electricity generation.
[0094] FIG. 1A shows a cross-section of a tidal energy conversion
assembly 100, according to an illustrative implementation. The
tidal energy conversion assembly 100 includes a displacement vessel
102 that is attached to a plurality of anchor cables 103a-103c and
anchor cables 105a and 105b connected to anchors 108a-108e on the
stationary location 106. Each of the anchor cables 103a-103c has a
first end (e.g., at latches 107a-107e), a second end (e.g., at
connector 111), and a length in between the first end and the
second end. Each of the anchor cables 105a and 105b has a first end
at anchors 108e and 108d and a second end at connector 111. In this
embodiment, the displacement vessel 102 houses a directional
converter 109 that is coupled to anchor cables 103a-103c and 105a
and 105b and electrical power generator 116. The directional
converter 109 includes a drive cable 110 having connector 111 at
one end coupled to anchor cables (via connector 111), and at a
second end coupled to the drum 113. While FIG. 1A illustrates such
components as being located within the displacement vessel, one of
skill in the art understands that the same components may be
located outside the displacement vessel, as will be further
explained below.
[0095] Anchor cables 103a-103c extend from the displacement vessel
102 at respective latches 107a-107c and are threaded through
anchors 108a-108c to reach connector 111. Each anchor 108a-108e has
a pointed end embedded with the stationary location 106 and an eye
loop at the other end through which the anchor cables may be
threaded. The anchors 108a-108c are secured in stationary location
106, which may be the seabed or a platform elevated above the
bay/ocean floor. One of skill in the art will recognize that any
suitable number of cables can be attached to the displacement
vessel 102 at any point along the surface of the displacement
vessel 102 and any suitable number of anchors may be used to secure
anchor cables 103a-103c. Connector 111 may be, for example, a metal
ring, a latch, or any suitable device for coupling the anchor
cables to the drive cable 110. Alternatively, not shown in FIG. 1A,
the anchors may include a pulley through which the anchor cables
are threaded to help minimize friction.
[0096] The tidal energy conversion assembly 100 further includes
anchor cables 105a and 105b that are also attached to anchors 108d
and 108e, respectively, at one end and the directional converter
109 at the other end. While FIG. 1A illustrates the mixed use of
anchor cables 103 and 105, the invention contemplates the device
having a plurality of anchor cables 103 only or a plurality of
anchor cables 105 only.
[0097] The displacement vessel 102 may be partially or wholly
hollow and substantially or completely water-tight so that it is
buoyant in water. However, other non-hollow embodiments may be
used. In this embodiment, by floating at or near the surface 118 of
the water, the elevation or distance 119a of the displacement
vessel 102 relative to the stationary location changes as the tide
rises and falls. For example, as the tide rises, the vertical
distance 119a between the displacement vessel 102 and the
stationary location increases. Conversely, as the tide falls, the
vertical distance 119a between the displacement vessel 102 and the
stationary location decreases.
[0098] In FIG. 1A, the directional converter 109 is attached to at
least one anchor cable and housed within or upon the displacement
vessel 102. Due to the attachment to the anchor cable, the
direction converter 109 captures the force in the vertical rising
of the displacement vessel caused by the rising tide into
mechanical energy that may be converted/transmitted to by an
electrical power generator 116. The directional converter may thus
utilize drive cable 110, along with drive gear 112, drum 113, and
gearing mechanism 114 to translate the forces generated by the
vertical rise into rotational motion/forces that can actuate the
generator 116. The drum 113 may be fixed to an axle on the
converter and connected to the drive cable 110 such that a tension
force on the drive cable 110 will cause the drum 113 to rotate. The
drive gear 112 may be fixed on the same axle as the drum 113 and
operatively coupled to gearing mechanism 114 for ultimate
transmission to the generator. The gearing mechanism 114 may
include a gear multiplication arrangement, such as a gear
multiplication box, that converts a slower rotational input into a
faster rotational output. For example, the gearing mechanism 114
may take a slower rotation of a larger gear and convert that input
rotation into a faster output rotation of a smaller gear.
Additionally, the gearing mechanism 114 may convert input rotations
in both clockwise and counter-clockwise directions into an output
of a single rotational direction for the electrical power generator
116. Either the drive gear 112 or the gearing mechanism 114 may be
coupled to electrical power generator 116.
[0099] As indicated above, drive cable 110 is attached at one end
to connector 111, which is attached to anchor cables 103a-103c and
105a and 105b, and at its other end to drum 113. As the tide rises,
causing the displacement vessel also to rise vertically, the
movement of the drive cable 110 (as further discussed below) causes
drum 113, and thus drive gear 112, to rotate in either a clockwise
or counter-clockwise direction. The drive gear 112 may include one
or more gears on an axle in any suitable arrangement of gear sizes
and gear types. For example, the drive gear 112 may include a
single sprocket fixed on an axle the sprocket may be configured to
interface with a chain. In another example, the drive gear 112 may
include two gears of different radii fixed on separate axles and
mechanically coupled with one another. Optionally, the drive gear
112 may be mechanically coupled to a gearing mechanism 114. For
example, the drive 112 gear may be coupled to the gearing mechanism
via a chain or belt. Alternatively, as another example, the drive
gear 112 may be directly coupled with one or more other gears that
are part of the gearing mechanism 114.
[0100] FIG. 1D shows an enlarged view of an alternative directional
converter 109 having a rack 117a and pinion 117b mechanism. The
rack 117a and pinion 117b mechanism is coupled to the drive cable
110 and the drive gear 112 or, alternatively, a gear of the gearing
mechanism 114. As the tide rises, via the attachment to the anchor
cable, the drive cable 110 pulls on the rack 117a and pinion 117b
mechanism, causing the rack 117a to translate along the pinion
117b. The pinion is coupled to a gear that is fixed on axle 115 and
thus, rotation of the pinion causes the gear on axle 115 to rotate.
Drive gear 112 is also fixed to the axle 115 and thus rotates due
to the rotation of the axle 115. The drive gear 112 may be coupled
to a gearing mechanism 114 such that the rotation (and thus
rotational energy) is transferred through the gearing mechanism 114
to the electrical power generator to generate electricity. This
configuration may not use a drum 113 as described above, and may be
beneficial for tidal energy conversion assemblies that are used in
areas of the ocean with smaller changes in the water surface due to
tidal action as a large drum and lengthy cable need not be
included. FIG. 1E shows a general implementation of a rack 117a and
pinion 117b mechanism for capturing energy from the rising and
falling of the tide.
[0101] As shown by comparing FIGS. 1A and 1n FIG. 1B, as the tide
rises, the displacement vessel 102 rises from a distance 119a to a
second higher distance 119b between the stationary location 106 and
the displacement vessel 102. Such rise of the displacement vessel
causes the portion of anchor cables 103a-103c between attachment
point 107a-107c and their anchors 108a-108c to lengthen, while the
portions between the anchors 108a-108c and connector 111 shorten;
as a result, the anchor cables 103a-103c exert a downward force
upon connector 111 and thus upon drive cable 110 which will cause
drum 113 to turn as the cable 110 unwinds. Drive gear 112 is
coupled to the same axle as the drum 113, and thus the rotation of
the drum 113 causes the drive gear 112 to rotate. The rotation of
the drive gear 112 is transmitted to the gearing mechanism 114
which may convert the RPM of the drive gear into a faster RPM
output. The output of the gearing mechanism 114 is transmitted to
the generator 116, which produces electricity.
[0102] As the displacement vessel rises vertically, the anchor
cables 103a-103c are free to slide through the loop of anchors
108a-108c as the displacement vessel 102 rises and falls with the
tide. However, the anchors 108a-108c may include a pulley mechanism
through which the anchors cables are threaded to reduce friction
between the anchor cables 103a-103c and the anchors 108a-108c.
Also, as the displacement vessel rises to distance 119b, the drive
cable may be fixed relative to the stationary location 106 by
anchor cables 105a and 105b. The fixed position of the anchor
cables 105a and 105b also activates the drive cable 110 as the
displacement vessel 102 changes its position relative to the
stationary location 106. The individual and collective function of
anchor cables 103a-103c and 105a and 105b causes drive cable 110 to
turn the drum 113 and drive gear 112 and thus provide mechanical
power to the electrical power generator 116.
[0103] In another example, as the tide falls vertically, the
displacement vessel 102 lowers, and the vertical distance 119a
between the anchor points 108a-108e and the displacement vessel 102
decreases. In the reverse direction, as the displacement vessel 102
falls vertically with the falling tide, an optional frame may be
positioned above the displacement vessel 102 and may include an
attachment mechanism, e.g., a cable, coupled to the directional
converter 109 to capture the change in potential energy in the
opposite direction due to the falling of the displacement vessel
102. The stationary frame is immobile with respect to the water
movements, and, as the displacement vessel 102 falls vertically
with the tide, the displacement vessel increases its distance from
the frame, generating a pulling force upon the cable attached to
the frame. The direction converter 109 coverts this pulling force
into mechanical energy and transmits the mechanical energy to the
generator for generation of electricity, therefore capturing energy
from the falling tide. At the same time, the action of the frame
and cable on the falling tide may cause the drum to rewind the
cable 110 such that the power generation can be repeated on the
next rising tide cycle.
[0104] The stationary frame may be substantially similar to a spud
barge used in marine operations. A spud barge, or jack-up barge, is
a type of buoyant vessel which is capable of providing a solid,
stable platform for offshore operations involving supporting heavy
machinery or equipment on water. Each spud barge may include at
least one support beam or pipe coupled to the barge (usually to the
barge's perimeter) that is driven into the sea floor to increase
the stability of the barge.
[0105] In an alternative approach for capturing potential energy
during the falling of the tide, the directional converter 109 may
include a compression spring coupled to an axle 115 on which the
drum 113 is fixed. The spring may store potential energy as its
coils are compressed by the rotation of the drum 113 due to the
unwinding of the anchor cable or drive cable from the drum 113. As
the displacement vessel 102 falls with the tide, the coils of the
spring may expand (from the forces stored in the compressed coils)
causing the axle 115 to rotate in an opposite direction and produce
rotational energy that is then transmitted to the electrical power
generator for generating electric power during the falling tide.
This spring mechanism will also serve to re-wind (or reel-in) the
anchor cable so the electrical power generation sequence can repeat
on the next rising tide.
[0106] Alternatively, a small low-power motor can be used to
re-wind the cable during the falling tide to ready the assembly for
the next incoming tide cycle. In an alternative embodiment, the
spring may be located within, for example, the gearing mechanism.
In this case, the spring mechanism may be coupled to an axle of a
gear in the gearing mechanism. A configuration such as this where
the spring mechanism is separated from the drum 113 may be
beneficial for maintenance/repairs or access of directional
converter components.
[0107] In FIGS. 1A and 1B, the electrical power generator 116
receives mechanical power from the directional converter 109,
generates electricity with the mechanical power, and outputs the
generated electricity through a wire 104, which then may be stored
in an electric storage facility or transmitted to an electric grid
to be used immediately by a consumer. In one embodiment, the wire
104 may be connected to a power grid through an electrical
connection cable that is run along the seabed and may be disposed
at or near anchors 108a-108e. In one embodiment, the electrical
power generator 116 may be configured to convert the rotation in
the first and second directions from the gearing mechanism 114 or
drive gear 112 into electrical energy. In another embodiment, the
electrical power generator 116 may convert rotation in a first or
second direction into electrical energy. The electrical generator
may be configured to produce direct current (DC) or alternating
current (AC) electricity. Thus, the electrical power may be
supplied to the consumer in either DC or AC. The electrical
generator may further include an inverter to convert DC into AC.
Alternatively, the electrical generator may further include a
rectifier to convert AC into DC. The electrical generator may store
DC electricity in a storage facility, such as a battery, for use or
transmission to consumers at a later time. The tidal energy
conversion system may include any other suitable supporting
electrical equipment, such as a voltage regulator or transformer,
for example.
[0108] FIG. 1C shows an enlarged view of an embodiment of the
directional converter 109. As shown in FIG. 1C, drive cable 110 is
wound around the drum 113, which is fixed on an axle 115. Drive
gear 112 is also fixed on the same axle 115 as the drum 113 and may
additionally comprise a plurality of gears suitable to convert the
movement of the drive cable 110 into rotational kinetic energy at a
specific RPM. Drive gear 112 is connected to gearing mechanism 114
by a chain or belt. The drive cable 110 may be composed of
materials such as braided steel cable, fiber rope, chain, extruded
metal or polymer, or any suitable combination of materials. The
drive cable 110 may be attached to one or a plurality of anchor
cables in any suitable manner, such as a latch, ring, clamp,
tapered lock, flange, or any other suitable coupling mechanism.
[0109] FIG. 6A illustrates another embodiment of a directional
converter 609. In particular, directional converter 609 includes a
rotatable drum 613 fixed on an axle 615. An anchor cable may be
coupled to the rotatable drum such that it may be wound about or
unwound from the drum 613. A drive gear 612 is also fixed on the
same axle 615 as the rotatable drum 613. Drive gear 612 is
connected to a gearing mechanism 614 by a chain, for example, and
gearing mechanism 614 includes a plurality of gears 614a-614c. In
the directional converter 609, the gearing mechanism 614 is
configured as a gear multiplication arrangement. As the drive gear
612 turns at a first RPM, gear 614a will turn at a second RPM that
is faster than the first RPM because gear 614a has a smaller
diameter than the drive gear 612. Gear 614b is fixed on the same
axle as gear 614a and thus will also rotate at the second RPM. Gear
614c is coupled to gear 614b by a chain and will spin at a third
RPM that is faster than the second RPM, because the diameter of
gear 614c is smaller than the diameter of gear 614b. The gearing
mechanism 614 is also coupled to an electrical power generator 616
such that rotation of the drum 613 is transferred to the electrical
power generator 616 through the gearing mechanism 614 to generates
electricity.
[0110] FIG. 2 illustrates a tidal energy conversion assembly 200
having a cylindrical displacement vessel. The tidal energy
conversion assembly 200 is substantially similar to the tidal
energy conversion assembly 100 of FIGS. 1A and 1B. In this
embodiment, the displacement vessel 202 is in the shape of a
cylinder that floats at or near the surface 218 of the water. The
displacement vessel 202 is anchored to stationary location 206 by
anchors 208a-208e connected through anchor cables 203a-203e. Anchor
cables 203a-203e each have a length that extends from a first end
(e.g., respective latches 207a-207e) to a second end (e.g.,
connector 211), and threaded through anchors 208a-208e.
[0111] While not shown in FIG. 2, directional converter 209 is
coupled to an electrical power generator located at least partially
inside the displacement vessel, similar to the electrical power
generator 116 in FIG. 1. The electrical power generator converts
mechanical energy, such as rotational energy, supplied by
directional converter 209 as displacement vessel 202 rises or falls
into electrical energy and outputs the electrical energy through
wire 204.
[0112] FIG. 3 shows a system 300 of tidal energy conversion
assemblies. Each individual tidal energy conversion assembly in the
system 300 may be substantially similar to those devices described
generally above, or with respect to FIG. 1A-1C, 2, 4, or 5A-C. The
system 300 includes displacement vessels 302a-302c that are buoyant
at the surface 318 of the water. Each displacement vessel 302a-302c
is anchored to stationary location 306 by anchors 308a-3081 through
anchor cables 303a-303d, anchor cables 303e-303h, and anchor cables
303i-3031. Anchor cables have first ends connected to latches
307a-3071, and second ends connected to connectors 311a-311c, and
are threaded through anchors 308a-3081.
[0113] Each tidal energy conversion assembly 302a-302c houses or
supports a directional energy converter 309a-309c, which may be
substantially similar to the directional converters described with
respect to FIGS. 1A-1C and 6A. The directional converters 309a-309c
are mechanically coupled to electrical power generators that may be
substantially similar to the electrical power generators described
with respect to FIGS. 1A-1C and 6A. Each electrical power generator
outputs generated electrical energy through a respective electrical
wire 304a-304c. Wires 304a-304c may be joined together to transmit
the generated electricity to an electric storage facility or
directly to consumers to be consumed. While FIG. 3 illustrates only
three displacement vessels in the system, this invention includes
any number of such devices in a system that is capable of being
networked to generate electricity. Each tidal energy conversion
assembly may be controlled collectively or individually in the
system, for example, by a locking mechanism on each tidal energy
conversion assembly as discussed below. Such as system would be
capable of producing large amounts of electricity, for example,
several gigawatts, for consumption or storage.
[0114] FIG. 4 shows an alternate embodiment of a tidal energy
conversion assembly 400 with a displacement vessel having multiple
chambers or compartments. Tidal energy conversion assembly 400
includes a displacement vessel 402 that is buoyant at the surface
418 of the water and has multiple internal chambers 423a-423h
arranged in a stacked orientation. While chambers 423a-423h are
shown in a stacked orientation, one of skill in the art would
recognize that the chambers 423a-423h can be arranged in any
suitable orientation. The internal chambers 423a-423h may be
manufactured from any suitable material so that each chamber may be
inflated to a specified and different pressure, for example, to
accommodate increasing static fluid pressure at increasing depths.
The pressures within each chamber may be similar or different from
one another, depending on the external static fluid pressure acting
on the tidal energy conversion assembly 400. Furthermore, each of
chambers 423a-423h may include a wall thickness that is
substantially similar to one another or different, depending on the
pressure desired for the individual chamber to accommodate for
static fluid pressure at increasing depths. For example, chamber
423d may comprise a thicker wall so that it can be inflated to a
higher pressure while chamber 423a may comprise a thinner wall and
be inflated to a lower pressure. Displacement vessel 402 may
comprise substantially the same stationary locations, anchors,
anchor cables, directional converter, and drag converter discussed
generally above and below.
[0115] The internal chambers 423a-423h may be manufactured from any
suitable material, or be an integral part of the displacement
vessel 402, so that each chamber may be inflated to a specified
pressure. Pressure within each chamber may be similar or different
from one another, depending on the buoyant force required of the
tidal energy conversion assembly 400. Furthermore, each of the
chambers 423a-423h may include a respective wall thickness. Each
wall thickness may be substantially similar to one another or
different, depending on the pressure required for the individual
chamber. The internal compartments may be stacked one on top of the
other. For example, a chamber 423d at the bottom of the
displacement vessel may include a thicker compartment wall so that
it can be inflated to a higher pressure while chamber 423a at the
top of the displacement vessel may include a thinner compartment
wall and be inflated to a lower pressure such that the chamber 423d
at the bottom can withstand greater compression pressure from the
external environment.
[0116] As another aspect of the present invention, a locking
mechanism (not shown) or rotation limiter may be included in the
directional converter 109 to lock the displacement vessel 102 at a
desired distance above the stationary location. For example, the
displacement vessel 102 may be locked at a low point in a tidal
cycle, where the displacement vessel 102 is close to the stationary
location 106. The displacement vessel 102 may be released at a
desired time when the tide is higher, e.g., at or close to high
tide, thereby allowing the displacement vessel 102 to vertically
rise a maximized distance from the stationary location 106 in a
short period of time. The locking mechanism thus allows the
displacement vessel to generate a maximized amount of energy in a
relatively short time interval, as compared to the gradual vertical
rise of a displacement vessel without a locking mechanism. The time
of release of the displacement vessel 102 may correspond to a peak
electric usage time of consumers. The locking mechanism thus allows
the tidal energy converting system 100 to compensate for times of
peak energy usage without necessitating storage of the generated
energy in an electric storage facility or battery. Locking the
displacement vessel 102 at a point close to the stationary location
can also generate large amounts of electricity in a short
time-frame, rather than with the gradual rise and fall of the
tide.
[0117] The locking mechanism may be coupled to the drive gear 112
or axle 115 to limit or inhibit the rotation of the drive gear 112
and/or axle. Alternatively, the locking mechanism may be coupled to
the drive cable 110 to limit or inhibit the translation of the
drive cable 110 and lock the displacement vessel 102 at a desired
distance above the seabed. In another example, to lock the
displacement vessel 102 in place at a specific elevation above the
stationary location 106, the locking mechanism may limit or prevent
rotation of the drum 113. As the drum 113 is limited or prevented
from rotating, the length of the drive cable 110 between the
stationary location 106 and the displacement vessel 102 will not
change and thus the displacement vessel 102 will be locked at the
specific elevation above the stationary location 106. The locking
mechanism may include a braking mechanism that is positioned such
that it may control the translation of the drive cable 110 (or an
anchor cable). For example, the locking mechanism may include a
clamp that is configured to apply a force on the drive cable 110
(or an anchor cable). The clamp may provide a clamping force on the
drive cable 110 such that translation of the drive cable 110 is
stopped or provide a force such that the translation is slowed.
[0118] In yet another aspect of the present invention, the
displacement vessel that is attached below a frame can be held or
locked in an elevated position by the frame. When the tide falls,
the lifting mechanism maintains the displacement vessel at an
elevated height over the lowered water level. When power is needed,
the displacement vessels may be released, and the falling weight of
the displacement vessel will exert a force on the spring or cable
connected to the lifting mechanism. The directional converter may
convert the force into mechanical energy and transmit the
mechanical energy to an electrical power generator to generate
electricity for storage and/or consumption. The time of release may
correspond to a peak energy usage time of consumers so that the
electrical energy does not need to be stored.
[0119] In another aspect of the invention, the invention comprises
a method of generating electricity from the vertical tidal motion
into rotational energy and transferring the resulting rotational
energy to operate an electrical power generator for producing
electricity. As the tide rises and/or falls, a vertical distance
between the surface of the water and the bay/ocean floor will
change. This vertical change in distance may be converted into
rotational energy that is used to energize the electrical power
generator to generate electricity. Specifically, the invention
includes a method of generating electricity from tides comprising
the steps of: providing a displacement vessel housing a directional
converter coupled to a generator, said displacement vessel being a
first distance from a stationary location below said displacement
vessel; providing an anchor cable having a first end and a second
end, whereby said second end is attached to said directional
converter and said anchor cable extends to an anchor secured at
said stationary location, the anchor cable having a first length
between said directional converter and said anchor; causing said
displacement vessel to change its distance from the stationary
location to a second distance wherein said second distance is
greater than said first distance and activating said directional
converter; and energizing said generator.
[0120] To calculate an expected energy return from a single
displacement vessel using the vertical rising of the tides for
energy generation, a buoyant force must be calculated for an
individual displacement vessel. Eqn. 1 shows an equation for
calculating buoyant force from a displacement vessel, where F.sub.B
is buoyant force, .DELTA..sub.V is the change in displaced volume
of the displacement vessel, p.sub.f is density of the water, and
F.sub.g is the force of gravity. The change in displaced volume
.DELTA.V of the displacement vessel is calculated by taking the
water plane area A.sub.wp of the displacement vessel multiplied by
the change in depth of the water h, shown in Eqn. 2.
F.sub.B=p.sub.f*F.sub.g*.DELTA.V (Eqn. 1)
.DELTA.V=A.sub.wp*h (Eqn. 2)
As the displacement vessel rises with the tide, the force exerted
on the directional converter will be constant over the distance
that the displacement vessel rises to the water surface. Eqn. 3
shows an equation for the energy E.sub.1 produced in Joules during
the rising of the tide, where D is the distance that the water
level rises.
E.sub.1=F.sub.B*(D-h) (Eqn. 3)
After the displacement vessel has traveled a distance D-h, the
displacement vessel will be submerged a distance h under the water
surface. As the displacement vessel continues to rise, the volume
of water displaced by the displacement vessel will decrease
linearly to zero, providing an average buoyant force F.sub.avg
shown in Eqn. 4.
F.sub.avg=1/2*p.sub.f*F.sub.g*V (Eqn. 4)
Eqn. 5 shows an equation for calculating the expected energy
produced in Joules as the displacement vessel rises above the
surface of the water. Eqn. 6 shows the total energy E.sub.total
produced from the rising of the displacement vessel is the sum of
E.sub.1 and E.sub.2 . . .
E.sub.2=1/2*p.sub.f*F.sub.g*V*h (Eqn. 5)
E.sub.total=E.sub.1+E.sub.2 (Eqn. 6)
The maximum energy produced will occur when the derivative of
E.sub.total with respect to h is equal to zero, giving a solution
of h equal to D. Eqn. 7a shows an equation for the maximum energy
E.sub.max produced by a displacement vessel if it is released when
the tide is at its highest point. Because in many areas of the
Earth, the ocean experiences 2 high tides and 2 low tides in a day,
the displacement vessel may travel up to a peak height of high tide
twice a day, as shown by Eqn. 7b.
E.sub.max=1/2*p.sub.f*F.sub.g*A.sub.wp*D.sup.2 (Eqn. 7a)
E.sub.max=p.sub.f*F.sub.g*A.sub.wp*D.sup.2 (Eqn. 7b)
[0121] Lastly, Eqn. 8 shows an equation to calculate expected power
(P) in Watts for an individual displacement vessel, where E.sub.max
is maximum energy and t is time.
P.sub.expected=E.sub.max/t (Eqn. 8)
[0122] As an example of calculating the force generated by using
the rising of the tide, using a density of 1026 kg/m.sup.3 for
ocean water, and that a tide will raise or lower the displacement
vessel by 20 m, a 100 m.times.100 m.times.10 m displacement vessel
will produce expected energy of 4.03.times.10.sup.10 Joules
according to Eqn. 7b. Using Eqn. 8, the expected power of one
displacement vessel over the course of a 24 hour period is
approximately 454 kW. A system of 100 similar displacement vessels
would thus generate approximately 45.4 MW.
Energy Generation Using Drift/Drag
[0123] In another aspect of the present invention, the tidal energy
conversion assembly utilizes drag forces caused by the ebb and flow
of water during tidal action to generate energy. Additionally, the
tidal energy conversion assembly may utilize drag forces caused by
other currents or water flows to generate energy. The ebb and flow
of water due to tidal action causes the tidal energy conversion
assembly to drift laterally relative to a stationary location. The
tidal energy conversion assembly may be substantially similar to
the tidal energy conversion assemblies as described above and
illustrated in FIG. 1A-1C, 2, or 4, which include at least one
anchor cable attached to displacement vessel that has a directional
converter and electrical power generator. Preferably, the
directional converter and generator may be located away from the
displacement vessel. Currents from the tide may cause the
displacement vessel to drift in a horizontal or lateral direction
relative to the stationary location and a length between the
stationary location and the displacement vessel changes. As the
directional converter is attached to the anchor cable, a force is
exerted on the directional converter by the displacement
vessel.
[0124] FIGS. 5A-5C show a tidal energy conversion assembly 500
having a displacement vessel 502 that is buoyant at the surface 518
of the water and houses or supports a directional converter 509. In
this embodiment, the directional converter 509 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.
Generally, the tidal energy conversion assembly 500 may be
substantially similar to the tidal energy conversion assemblies of
any one of FIG. 1, 2, or 4. The displacement vessel 502 is anchored
to the stationary location 506 at anchor 508 by anchor cable 503.
The directional converter 509 and anchor cable 503 may comprise any
of the embodiments described and shown above, for example, FIGS.
1A-1D and 6A. The displacement vessel 502 further includes an
electric power generator for generating electricity from the drag.
In this embodiment, anchor cable 503 has a first end at latch 507
and a second end connected to directional converter 509, defining a
length therebetween. Anchor cable 503 is threaded through the
anchor 508 (which can be either a loop or a pulley).
[0125] In this embodiment, the directional converter 509 includes a
drum 513 and control mechanism 520. FIG. 5D shows an enlarged view
of the directional converter 509 configured for drag energy
conversion.
[0126] In FIG. 5A, displacement vessel 502 is resting at a point
directly above anchor 508 at a distance 519a above the anchor 508.
Anchor cable 503 has a length L.sub.1 from displacement vessel 502
to anchor 508. Tidal drag forces may shift displacement vessel 502
in a lateral direction 522a with respect to its original position.
When the tide rises vertically as shown in FIG. 5B, displacement
vessel 502 rises to a distance 519b, which is greater than distance
519a, and the tide pushes the displacement vessel 502 a lateral
distance of H.sub.1. The anchor cable 503 increases to a length of
L.sub.2 between the displacement vessel 502 and anchor 508. L.sub.2
is greater than L.sub.1 and 519b is greater than 519a. The increase
in distance of L.sub.1 to L.sub.2 causes the drum 513 of the
directional converter 509 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 502
returns to the position over anchor 508, for example, by the use of
a positioning system on the displacement vessel 502. Slack in the
anchor cable 505 may be brought into and stored within the
displacement vessel 502 by a control mechanism 520, e.g., a motor
or a spring coupled to the drum 513.
[0127] In FIG. 5C, the displacement vessel 502 is resting at a low
point in the tidal cycle at a distance 519c between the
displacement vessel 502 and the anchor 508. and anchor cable 503
has a length L.sub.3 from the displacement vessel 502 to the anchor
508. When the tide falls vertically as shown in FIG. 5C, the tides
drags the displacement vessel 502 a lateral distance of H.sub.2 in
direction 522b and the displacement vessel 502 falls vertically to
a distance 519c. The length L.sub.3 may increase in length due to
the falling tide Where L.sub.3 is greater than L.sub.1, the
increase in length from L.sub.1 to L.sub.3 causes the drum 513 of
the directional converter 509 to rotate. The rotation can be
captured by an electrical power generator to generate electricity.
As the tide returns, the displacement vessel 502 returns to the
position over anchor 508, for example, by the use of a positioning
system on the displacement vessel 502. Any slack in the anchor
cable may be returned to the drum 513 by a control mechanism
520.
[0128] In an aspect of the present invention, the displacement
vessel 502 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 seabed. Initially,
the displacement vessel 502 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 502 moves in a lateral
direction due to the ebb and flow of water during tidal action, the
anchor cable 503 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.
[0129] In another aspect of the invention, the displacement vessel
502 may include a drag panel 521 extending from one of the exterior
surfaces of the displacement vessel 502. The drag panel 521 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
521 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 521 may be secured to a bottom side of the displacement
vessel 502 and extend in a generally downwards direction. The drag
panel 521 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 521 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 521 may include
support structures, such as reinforcement bars, that may extend
from the displacement vessel to any point on the drag panel
521.
[0130] The drag panel 521 may include a control mechanism such that
the control mechanism may deploy and retract the drag panel 521
from the displacement vessel. For example, the drag panel 521 may
be stored within the displacement vessel in a first stored
position. The control mechanism may controllably deploy the drag
panel 521 at a specified time, such as a time when strong current
conditions exist, to a second deployed position. If the drag panel
521 is not needed, the control mechanism may retract the drag panel
521 back into the first position inside the displacement vessel.
The first position may alternatively be a configuration where the
drag panel 521 is substantially adjacent to a surface of the
displacement vessel 502. The drag panel 521 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 502.
[0131] In another embodiment of the invention, 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 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.
[0132] 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 again in the first direction. Thus,
electric power can be generated during both general directions of
travel.
[0133] FIG. 22 illustrates the general approach to dual-direction
power generation according to the invention wherein a displacement
vessel is located between two generally fixed positions in an area
of tidal action, with at least one generator and at least one
directional converter mounted on one of the vessel or either fixed
positions. This dual-direction power generation approach may allow
for twice the electrical generation capacity compared to other
single direction power generation embodiments. In one embodiment, a
generator is mounted to the displacement vessel 2202 and coupled to
first 2206a and second 2206b stationary locations via two
directional converters such that the generator turns in one
direction as the tidal action causes the vessel to move towards the
first stationary location 2206a and the generator spins in the
opposite direction as the tidal action causes the vessel to move
towards the second stationary location 2206b and thus generate
electrical power during both the ebb and the flow segments of every
tidal cycle. In this embodiment, the generator may be coupled to
two drums that can spin the generator in either rotational
direction. The coupling between the generator and the drums may
include a pair of cables, where each cable is secured at one of its
ends to one of the stationary locations and wrapped at the opposite
ends to one of the generator drums but in opposite clockwise
manner. As the displacement vessel 2202 moves in the first
direction, the generator spins in a first rotational direction, and
as the displacement vessel 2202 moves in the opposite direction,
the generator spins in the opposite rotational direction with the
result that (except for slack tides) the generator is essentially
constantly producing electrical power.
[0134] In yet another embodiment, a generator and directional
converter may be mounted to a first stationary location and coupled
to both the vessel and the second stationary location such that as
tidal action causes the displacement vessel 2202 to move in the
first direction, the generator and directional converter spins in
one rotational direction, and as the tidal action causes the
displacement vessel 2202 to move in the opposite direction, the
generator and directional converter spins in the opposite
rotational direction, and thus generate electrical power during the
entire tidal cycle (i.e., the ebb and the flow). Here, again, the
generator has two drums and a cable runs from one drum to a fixed
point secured to the vessel and thence to a drum (or like
rotational mechanism) on the second stationary location and thence
to the other generator drum. The cable ends are wound in opposite
directions around their respective generator drums to cause the
generator to spin in opposite directions as the displacement vessel
2202 moves in one direction and the other direction.
[0135] In yet another embodiment, a generator and directional
converter may be mounted to each of the stationary locations and
coupled to the displacement vessel 2202 such that as the tidal
action causes the displacement vessel 2202 to move in a first
direction, it causes both generators to spin and generate
electrical power, and as the tidal action causes the displacement
vessel 2202 to move in the opposite direction, it causes both
generators to spin (in opposite rotational directions relative to
their rotations during displacement vessel 2202 movement in the
first direction, but not necessarily relative to each other) to
generate electrical power during the entire tidal cycle. In this
version, a single cable is fixed at both ends to the vessel and
wrapped around the drums of both directional converters to spin
both of them during any movement of the displacement vessel 2202.
In this embodiment, the result could be twice the electrical power
generation during each tidal cycle.
[0136] Thus, tidal energy generation assembly 2200 has two
directional converters 2209a and 2209b disposed on opposite
stationary locations 2206a and 2206b and an anchor cable 2203
connecting the two directional converters 2209a and 2209b to a
displacement vessel 2202. In FIG. 22, the displacement vessel 2202
includes a drag panel 2221 and generates electricity when traveling
in a first direction 2222a due to the flow of water by unwinding a
drum that is coupled to an electric generator in the first
directional converter 2209a. When the tide changes the direction of
water flow, the displacement vessel 2202 may travel in a second
direction 2222b that is opposite to the first direction. The
displacement vessel 2202 also generates electricity when traveling
in the second direction 2222b by unwinding a drum that is coupled
to an electric generator in the second directional converter
2209b.
[0137] FIG. 6B illustrates a displacement vessel frame 602 suitable
for energy generation using drift or drag as described above and in
related to 5A-5C. Displacement vessel frame 602 may be used in
conjunction with the directional converter, such as the directional
converter 609 shown in FIG. 6A. Displacement vessel frame 602 may
include a buoyancy mechanism such that it may be configured, as is
known in the art, to float at the surface of the water and hold the
directional converter 609 shown in FIG. 6A. The displacement vessel
frame 602 may include a waterproof skin using materials
conventional in the art to protect the frame from the ocean
environment. Displacement vessel frame 602 includes a streamlined
hull and may include a drag panel extending through slot 730 from
the bottom of the displacement vessel frame 602. The drag panel
will function similarly to the drag panel described above in
relation to FIGS. 5A-5C.
[0138] FIG. 6C shows a displacement vessel 602 having a skin.
Displacement vessel 602 may include a structure or frame as
described above with respect to FIG. 6B 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 602 further includes a
drag panel 612 as described above with respect to FIGS. 5A-5C. In
this embodiment, an anchor cable 603 is connected to the drag panel
612 at both sides of the drag panel 612. The location along the
drag panel 612 where the anchor cable 603 is connected may
correspond to a center of mass of the displacement vessel 602, such
that when a current causes the displacement vessel 602 to drift,
the displacement vessel 602 will remain relatively stable in the
water while maintaining a force on the anchor cable 603. The other
end of the anchor cable 603 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, as will be described in more
detail with respect to FIGS. 8 and 9.
[0139] In another embodiment, as shown in FIG. 7, the displacement
vessel 752 may itself be a drag panel (for example, without the
displacement vessel frame shown in FIG. 7B). For example, the
displacement vessel 752 may be a hollow plate, having a ballast
with a density that is less than that of water such that the
hollow-plate displacement vessel remains buoyant in the water. The
ballast may be a subsea ballast fixed to the displacement vessel
752 to generate additional buoyant forces to keep the displacement
vessel afloat. In an embodiment, the buoyant force generated by the
displacement vessel 752 may be approximately equal to the weight of
the displacement vessel 752 such that the displacement vessel 752
remains buoyant at an elevation above the bay/ocean floor. The
displacement vessel 752 may be attached to an anchor cable 753 in
any configuration (for example, as at the corners of the
displacement vessel) such that displacement vessel 752 remains
captures the forces caused by the ebb and flow of water. Two or
more such displacement vessels may be connected together by, for
example, welding to create a larger displacement vessel, to any
size as desired. If two or more such displacement vessels are
connected together, the two or more displacement vessels may be
spaced apart by, for example, struts to define a gap or window in
the displacement vessel.
[0140] The displacement vessel 752 may include a floatation device
760 configured to indicate the location of the displacement vessel
752, provide GPS information, and/or provide additional buoyant
forces. The displacement vessel 752 or floatation device 760 may
include a processing or logic module configured to transmit
information about the tidal energy conversion assembly to an
operator. For example, the processing or logic module may record
data corresponding to current speed, displacement vessel speed,
displacement vessel location, efficiency of the system, and
buoyancy forces. The processing module may be coupled to a
transmitter located, for example, on the displacement vessel or
floatation device 760, such that the processing module may transmit
the recorded data to an operator using the transmitter. The
transmitter may be a wireless transmitter/receiver as is known in
the art.
[0141] FIG. 8 shows a displacement vessel 802 having an array of
directional converters 809a-809f and generators 816a-816f at a
stationary location 806. In this embodiment, 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 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.
[0142] 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 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.
[0143] 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.
[0144] In one embodiment, 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 15
kW at 125 RPM. Alternatively, each of generators may have different
electrical output ratings. For example, the generators 816a-816f
may have different electrical output ratings at 1 kW, 5 kW, 10 kW,
15 kW, 20 kW, and 25 kW. In another example, the generators
816a-816f may have similar electrical output ratings of 15 kW.
[0145] 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 FIG. 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.
[0146] In another embodiment, the displacement vessel may be locked
at a particular distance away from the stationary location through
a locking mechanism as described above, while at least one or more
generators are engaged throughout the tidal cycle. The locking
mechanism may be released by, for example, a control mechanism, to
allow the displacement vessel to drift horizontally relative to the
stationary location when the control mechanism determines that a
fast enough current is present to move the displacement vessel at a
desired speed to generate electricity. It is understood that as the
current speed caused by the ebb and flow of water due to tidal
action varies, the amount of electricity generated by the tidal
energy conversion assembly may also vary. The currents caused by
the ebb and flow of tidal action generally vary in a sinusoidal
pattern and thus the amount of electricity generated may also vary
in a similar manner. One of skill will recognize that the number of
generators engaged or the rate at which the engaged generators will
rotate may vary as the speed of the currents and/or the rise and
fall of the tide vary throughout the tidal cycle.
[0147] FIG. 9 shows displacement vessels 902a and 902b having two
directional converters 909a and 909b on land and a pulley
arrangement 926, the two directional converters attached to a
single generator 916. The displacement vessels 902a and 902b may be
substantially similar to the displacement vessel described above
with respect to FIGS. 5A-5C, 7C, and 8. Each of displacement
vessels 902a and 902b is coupled to an anchor cable 903 that is
looped around a pulley arrangement 926 located in the ocean away
from the stationary location 906. The pulley arrangement 926 may
include a pulley fixed on an axle, such that the anchor cable 903
may be threaded through the pulley and may translate with little
resistance. The axle and pulley of the pulley mechanism may be
fixed to a platform or other structure in the ocean. The anchor
cable 903 is connected at a first end to a directional converter
909a and at a second end to directional converter 909b. The
directional converters are substantially similar to those described
above and include drums 913a and 913b fixed to axles 915a and 915b
which include drive gears 912a and 912b. The drive gears 912a and
912b are operatively coupled to gear boxes 914a and 914b and the
gear boxes 914a and 914b are operatively coupled to a generator
916. The generator 916 may be connected to a storage facility 924
or directly connected to an electrical power grid via a wire
904.
[0148] As the ebb and flow of tidal action causes the displacement
vessels 902a and 902b to drift laterally toward the stationary
location 906 in a first direction, the anchor cable 903 exerts a
force on the first directional converter 909a, causing the first
directional converter 909a to transmit mechanical power to a
generator 816 to generate electrical power. The second directional
converter 909b may reel in any excess slack in the anchor cable 903
by using, for example, a control mechanism similar to that
described above. As the ebb and flow of water due to tidal action
causes the displacement vessels 902a and 902b to drift in a second,
different lateral direction away from the stationary location 906,
the anchor cable 903 exerts a force on the second directional
converter 909b, causing the second directional converter 909b to
transmit mechanical power to the generator 916 to generate
electrical power. In this way, the pulley arrangement 926 allows
for electrical power to be generated using both the ebb and flow of
water due to tidal action or other currents. In an alternative
embodiment, the second directional converter 909b may be
operatively couple to a second generator (not shown). The second
generator may have a similar or different electrical out rating as
the first generator 916.
[0149] In an alternative embodiment of FIG. 9, the anchor cable may
be continuous loop (rather than an anchor cable having two ends).
In this embodiment, the directional converters are axles (rather
than drums) around which the anchor cable is wound. As the
displacement vessel drifts toward or away from the stationary
location, pulling upon one direction of the anchor cable, the
anchor cable is configured to turn the axle, and such movement of
the axle is configured to energize one or more generators.
[0150] In another embodiment, at least part of the anchor cable 903
may be submerged under the water, such as at a desired operating
depth of the displacement vessel, for example. In this embodiment,
the anchor cable may be attached at the proximal end to a
stationary location on land and operatively coupled to a
directional converter and generator. From this proximal end, the
distal portions of the anchor cable 903 (including the distal end
of the anchor cable 903) may be submerged by being threaded through
one or more connections, such as an anchor or pulley that is
located under the water at, for example, the bay/ocean floor or a
submerged platform. After the anchor cable 903 is threaded through
the connection, the displacement vessel may be coupled at any point
along the distal portion of the anchor cable 903 or at the distal
end of the anchor cable 903. As the displacement vessel moves in a
first lateral direction relative to the stationary location, anchor
cable 903 may be activated to generate electricity as described
above. The displacement vessel may be attached to a plurality of
submerged anchor cables that are as described above. The proximal
ends of such other submerged anchor cables may be attached to other
stationary locations and operatively coupled to other directional
converters and/or generators at such stationary locations. As the
displacement vessel moves in another lateral direction relative to
the stationary location, such other anchor cables may be activated
to generate electricity. Each directional converter may include a
control mechanism for rewinding the cable, as discussed above.
[0151] In yet another embodiment, the displacement vessel may be
attached to the distal end of the submerged first anchor cable 903
and the distal end of a submerged second anchor cable, where the
submerged first anchor cable 903 extends in one direction away from
the displacement vessel and the submerged second anchor cable
extends in the opposite direction away from the displacement
vessel. As the submerged second anchor cable extends away from the
displacement vessel, the distal portion of the second anchor cable
may be threaded through a pulley that returns such submerged second
anchor cable toward the displacement vessel and the submerged first
anchor cable 903, and the proximal end of the submerged second
anchor cable is attached to the same stationary location as anchor
cable 903. The proximal end of the second anchor cable may be
operatively coupled to the same or different directional converter
and generator as the anchor cable 903 at the stationary location.
In this arrangement, energy may be produced by the drag forces
produced on the displacement vessel while the tide is both ebbing
and flooding, because the first submerged anchor cable will be
engaged as the tide ebbs, and the second submerged anchor cable
will be engaged as the tide floods.
[0152] FIG. 10 shows a bottom view of displacement vessel 1000 that
is adapted to be rotatable, as indicated above and as further
explained below. The displacement vessel 1000 may be adapted to
float in the water by way of a floatation device as described above
and below. The displacement vessel 1000 includes a drag panel 1002
having a first side 1002a and a second side 1002b that are adapted
to capture drag forces from the flow of water due to tidal action
and/or other water flows. The first side 1002a and second side
1002b 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.
[0153] To illustrate the general case of controlling the angle
according to one aspect of the invention, the displacement vessel
1000 further includes control cables 1008a and 1008b extending from
the drag panel 1002 adapted to controllably adjust the orientation
of the drag panel 1002 in the water. The control cables 1008a and
1008b may be coupled to an anchor cable 1003 at one end via a
coupling mechanism 1009 and the anchor cable 1003 may be further
connected to a directional converter and a generator at a
stationary location, as described above. Each control cable 1008a
and 1008b may also be coupled at another end to a/an
adjustment/control mechanism (indicated generally as 1020a and
1020b) mounted on or within the displacement vessel 1000, such as a
motor and drum assembly or a winch, for example. Each control
mechanism 1020a and 1020b 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 1020a
may wind up (or shorten) control cable 1008a while a second control
mechanism 1020b releases (or lengthens) control cable 1008b, thus
rotating the displacement vessel 1000 in a clockwise direction and
controllably adjusting the amount of drag force exerted on the drag
panel 1002. The first control mechanism 1020a and second control
mechanism 1020b may also rotate the displacement vessel 1000 in the
opposite (counterclockwise) direction by the reverse operation,
i.e., the first control mechanism 1020a may release control cable
1008a and the second control mechanism 1020b may wind up control
cable 1008b. Those skilled in the art will hereby also recognize
that a single motor/drum or winch can be used with the cables
mounted in opposite directions and that as the drum/winch turns,
one cable is unwound and the other cable is wound. By providing a
displacement vessel 1000 that is capable of rotating in the water
to controllably adjust the drag force exerted on the drag panel
1002, the amount of electricity generated by the generator may also
be controllably adjusted.
[0154] In another embodiment, 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 embodiment, 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. In yet another embodiment, the displacement vessel may
include multiple drag panels extending into the water from the
bottom surface of the displacement vessel. In this embodiment, 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.
[0155] FIG. 11A shows an isometric front view of a displacement
vessel 1102 that is adapted to be rotatable and has an alternate
surface shape, as indicated above and as further explained below.
The displacement vessel 1102 includes a drag panel 1121 supported
by floatation devices 1160a and 1160b. The floatation devices 1160a
and 1160b may be similar to the floatation devices as described
above with respect to FIG. 7D and may be configured to float at or
near the surface of the water such that the drag panel 1121 is
disposed at a specified distance below the surface of the water
such that it may capture drag forces from water flow. In this
embodiment, the drag panel 1121 includes a first side 1121a and a
second side 1121b that each have a non-flat shape. In an example,
as shown in FIG. 11A, the drag panel 1121 includes a parabolic or
concave shape on sides 1121a and 1121b to enhance the capture of
drag forces from tidal action and/or tidal currents more
effectively than might be achieved by a flat panel. One of skill in
the art will understand from the foregoing that sides 1121a and
1121b of the drag panel 1121 may include other suitable shapes to
enhance (or reduce) capture of drag forces exerted on the drag
panel 1121.
[0156] The drag panel 1121 may be made of a fabric, metal,
composite, amorphous metal alloy, or polymer. In an embodiment of a
displacement vessel configured to operate where tidal currents are
relatively slow, a fabric drag panel may be sufficient. In other
embodiments where tidal currents are stronger, a metal or polymer
drag panel may be preferred.
[0157] The displacement vessel 1102 of FIG. 11A-11D is shown with
arms 1138a-1138c. Any suitable number of arms may be used on the
displacement vessel, or the displacement vessel may have no arms at
all. In the embodiment shown in FIGS. 11A-11D, arm 1138a may be
coupled to the drag panel 1121 via hinges 1106a that allow the arm
1104a to swing about the drag panel 1121. Arm 1138b may similarly
be coupled to the drag panel 1121 via hinges 1106b and may be
disposed on an opposite side of the drag panel 1121 from arm 1138a.
A third arm 1138c may be coupled to another side of the drag panel
1121 via hinges similar to those described above for arms 1138a and
1138b. The arms 1138a-1138c (shown conceptually in FIGS. 11A-11D)
may have substantially the same length D.sub.1 as the drag panel
1121, or may be longer or shorter than length D.sub.1. Preferably,
arms 1138a and 1138b have lengths such that they are each longer
than length D.sub.1 and arm 1138c has a length such that it is
longer than length D.sub.2. The hinges 1106a-1106c allow for the
arms 1138a-1138c to swing about the displacement vessel 1102 as the
displacement vessel 1102 changes its orientation in the water
relative to the anchor cable 1103. The use of multiple arms with
cables encapsulated within will serve to minimize wear on the
cables, avoid tangles of the cables, and/or prevent a cable from
dropping below the barge or displacement vessel.
[0158] The arms 1138a-1138c house control cables 1128a-1128c,
respectively, which are coupled at one end to an anchor cable 1103
via a connection 1111 at a first end of the anchor cable 1103 and
are coupled at the other end to a control mechanism that may reside
on or within the displacement vessel, as described in more detail
below. The connection 1111 may include, for example, a metal ring,
latch, clip, cable loop, or any other suitable coupling device for
connecting the control cables 1128a-1128c to the anchor cable 1103.
The anchor cable 1103 is further coupled to a directional
converter, as described above with respect to FIGS. 8 and 9, at a
second end of the anchor cable 1103. As also described above, the
directional converter may be operably coupled to a generator and
both the directional converter and the generator may be located at
a stationary location, such as land or a barge. Any of the anchor
cables, directional converters, and/or generators described above
and below may be used with the displacement vessel 1102.
[0159] In an embodiment of the displacement vessel 1102 having
arms, each control cable 1128a-1128c may reside (partially or
totally) within its respective arm 1138a-1138c through a conduit
(described in further detail below with respect to FIGS. 12A-12C).
As can be seen in FIGS. 11A-11D, the control cables 1128a-1128c
(shown in part as dotted lines) pass through the arms 1138a-1138c
to couple at one end to control mechanisms 1120a-1120c
respectively. The control mechanisms 1120a-1120c may reside on or
within the displacement vessel and may be adapted to wind up and/or
release the control cables 1128a-1128c to rotate the displacement
vessel 1102 in the water. Each control mechanisms 1120a-1120c may
independently wind up and/or release its respective control cable
to change a distance between an end of the displacement vessel and
the anchor cable 1103, causing rotation of the displacement vessel
1102 in the water. For example, a first control mechanism 1120a
housed within the displacement vessel 1102 may wind up control
cable 1128a while a second control mechanism 1120b housed within
the displacement vessel 1102 may release control cable 1128b to
change the displacement vessel 1102 orientation in the water and
rotate the displacement vessel 1102 clockwise. Alternatively, the
first control mechanism 1120a may unwind/release control cable
1128a while the second control mechanism 1120b may wind up control
cable 1128b to change the displacement vessel 1102 orientation in
the water and rotate the displacement vessel 1102 counterclockwise.
An operator may change the displacement vessel 1102 orientation in
the water to adjust the amount of drag force exerted on the drag
panel 1121, controllably adjusting the amount of electricity
ultimately generated.
[0160] In an embodiment, the arms 1138a and 1138b may be longer
than length D.sub.1 such that the control cables 1128a and 1128b
may extend away from either side of the drag panel 1121 and connect
to the anchor cable 1103 without contacting the surfaces of drag
panel 1121. Similarly, arm 1138c may extend past length D.sub.2
such that anchor cable 1128c may extend away from either side of
the drag panel 1121 and connect to the anchor cable 1103 without
contacting the surfaces of the drag panel 1121. This configuration
may be particularly useful to prevent the control cables
1128a-1128c from contacting the drag panel 1121 during operation
and/or causing frictional wear on the control cables
1128a-1128c.
[0161] While FIGS. 11A-11D illustrate arms 1138a-1138c having
control cables 1128a-1128c passing through a conduit in the arms
1138a-1138c, in another embodiment as described above with respect
to FIG. 10, the control cables 1128a-1128c may be directly attached
to the displacement vessel 1102 without running through any arms.
The control cables 1128a-1128c may be coupled directly to control
mechanisms 1120a-1120c residing on or within the displacement
vessel 1102, such as within one or both of the floatation devices
1160a and 1160b or within the drag panel 1121, for example. As
described above, the control mechanisms 1120a-1120c may be
configured to wind up and/or release the control cables 1128a-1128c
to adjust the distance and orientation of the displacement vessel
1102 from the anchor cable 1103 and orient the drag panel 1121 with
respect to the flow of water in a method similar to that described
above with respect to the embodiment of the displacement vessel
1002 with arms 1138a-1138c.
[0162] In operation, the displacement vessel 1102 is positioned in
the water such that a first side 1121a of the drag panel 1121
captures drag forces resulting from the pressure exerted on the
drag panel as a result of the water flow. To effect rotation of the
displacement vessel 1102, a first control mechanism 1120a may wind
or release the control cable 1128a either alone or while a second
control mechanism 1120b releases (or winds) the control cable
1128b. As the first control mechanism 1120a winds (or releases) the
first control cable 1128a, the first side 1121a of the displacement
vessel may change its distance relative to the anchor cable 1103
allowing the displacement vessel to change its orientation with
respect to the anchor cable and water flow. Where the displacement
vessel 1102 has hingeable arms, the hinges 1106a-1106c allow for
the arms 1138a-1138c to swing freely relative to the displacement
vessel 1102 as the displacement vessel 1102 changes its orientation
in the water relative to the anchor cable 1103. When the first side
1121a of the displacement vessel 1102 is perpendicular to the flow
of water, the displacement vessel 1103 may experience a larger
amount of drag force than if the displacement vessel 1102 were
oriented at another angle to the flow of water. Upon rotation of
the displacement vessel 1102 to a non-perpendicular angle, the drag
panel 1121 may experience less drag force, thus allowing the amount
of drag force exerted on the displacement vessel 1102 to be
controllably adjusted during operation. Such a displacement vessel
1102 that can be rotated in the water to change the amount of drag
force exerted thereon may be configured to capture a larger amount
of drag forces during peak electric usage times and capture a
smaller amount of drag forces during non-peak electric usage times.
Among other potential advantages, such controlled adjustability may
help reduce unnecessary stress on the apparatus and prolong its
useful life.
[0163] FIG. 11B shows a bottom view of a displacement vessel 1102
of FIG. 11A. As stated above, the displacement vessel 1102 includes
a drag panel 1121 having a first side 1121a and a second side
1121b. The first side 1121a and/or the second side 1121b may
include a parabolic or concave shape that is configured to increase
the capture of drag forces from the flow of water. The displacement
vessel 1102 further includes arms 1138a-1138c extending therefrom
and coupled to the drag panel 1121 via hinges 1106a-1106c. The arms
1138a-1138c each partially house a respective control cable
1128a-1128c (shown as a dotted line) and the control cables
1128a-1128c are coupled to an anchor cable 1103 via a coupling
mechanism 1111.
[0164] As shown in FIG. 11B, the displacement vessel 1102 further
includes stopping mechanisms 1135a and 1135b located at an opposite
end of the displacement vessel 1102 from the hinges 1106a and
1106b. Stopping mechanisms 1135a and 1135b are configured to limit
the range of motion of arms 1138a and 1138b so that the arms 1138a
and 1138b do not strike, and potentially damage, the drag panel
1102. The stopping mechanisms 1135a and 1135b may be manufactured
from any suitable material including rubber, metal, or a polymer,
for example. One of skill in the art will recognize that stopping
mechanisms 1135a and 1135b may be placed at any point along the
drag panel to limit the motion of the arms 1138a and 1138b.
Optionally, additional stopping mechanisms may be used to limit the
range of motion of the third arm 1138c on either side of the drag
panel 1121.
[0165] Together, FIGS. 11B-11D illustrate the rotation of the
displacement vessel. In FIG. 11B, the first side 1121a of the drag
panel 1121 faces the coupling mechanism 1111 and side 1121b is away
from the coupling mechanism 1111. As control cable 1128b is
lengthened by the second control mechanism 1120b and control cable
1128a is shortened by first control mechanism 1120a, the
displacement vessel 1102 may rotate clockwise, allowing the first
side 1121a to rotate away from coupling mechanism 1111 and the
second side 1121b to rotate towards coupling mechanism 1111. The
rotation of the displacement vessel 1121 adjusts the surface area
of the drag panel that is available to capture the flow of
water.
[0166] In FIG. 11C, the displacement vessel 1102 is in mid-rotation
between the configuration of FIGS. 11B and 11D. In particular, the
first side 1121a of the drag panel 1121 is rotating clockwise as
the control cable 1128a is shortened (or wound up) by the first
control mechanism 1120a residing on or within the displacement
vessel 1102 and as the control cable 1128b is simultaneously
lengthened (or released) by the second control mechanism 1120b
residing on or within the displacement vessel 1102, as described in
more detail with respect to FIGS. 12A-12C.
[0167] FIG. 11D illustrates the completion of the displacement
vessel 1102 rotation, where the second side 1121b now faces the
coupling mechanism 1111, and first side 1121a faces away from the
coupling mechanism. In FIG. 11D, control cable 1128a is shortened
as compared to its state in FIGS. 11B and 11C. Conversely, control
cable 1128b is lengthened in FIG. 11D as compared to its state in
FIGS. 11B and 11C. The displacement vessel illustrated in FIG. 11D
may be rotated back to the state in FIG. 11B in a substantially
similar method as described above.
[0168] FIG. 11E shows a side view of a displacement vessel 1102.
Further to the description of the floatation device in FIG. 7D, the
floatation device 1160 may be separated into two or more
compartments 1123a and 1123b. The first compartment 1123a may be
configured to be waterproof and/or store equipment, such as the
control mechanism described above. The second compartment 1123b may
include a material to maintain the buoyancy of the displacement
vessel 1102, such as a gas, for example, to increase the buoyancy
of the floatation device 1160. One of skill in the art will
recognize that both compartments 1123a and 1123b may be configured
to store a material to maintain buoyancy and/or house
equipment.
[0169] FIG. 12A shows a back view of a displacement vessel 1202.
The displacement vessel 1202 includes a drag panel 1221 supported
by floatation devices 1260a and 1260b. The floatation devices 1260a
and 1260b are configured to float at or near the surface of the
water such that the drag panel 1221 is disposed at a specified
distance below the surface of the water.
[0170] As shown in FIG. 12A, the floatation devices 1260a and 1260b
include a first cross section having a first diameter above the
water. The floatation devices 1260a and 1260b then taper to a
second cross section having a second, smaller diameter under the
water.
[0171] The displacement vessel 1202 of FIGS. 12A-12C further
includes an arm 1238 comprising a truss-like structure. The arm
1238 may be coupled to the drag panel 1221 via hinges 1206 that
allow the arm 1238 to swing about the drag panel 1221. As one
example, the arm 1238 houses the control cable 1228 through a
central conduit 1213 that extends along the arm 1238 and into the
floatation device 1260a. Through central conduit 1213, the control
cable 1228 may extend through arm 1238, be coupled to and stored
in, a control mechanism housed within the displacement vessel 1202,
such as in the floatation device 1260a, for example, as described
with reference to FIG. 7D.
[0172] FIG. 12B shows a top view of a displacement vessel 1202. As
stated above, the displacement vessel 1202 includes a drag panel
1221 having a first side 1221a and a second side 1221b. The
displacement vessel 1202 further includes arms 1238a and 1238b
extending therefrom and coupled to the drag panel 1221 via hinges
1206a and 1206b. The arms 1238a and 1238b are each coupled to a
respective control cable 1228a and 1228b and the control cables
1228a and 1228b are coupled to an anchor cable 1203.
[0173] FIG. 12C shows a side view of a displacement vessel 1202.
The displacement vessel 1202 includes a drag panel 1221 that is
supported by a floatation device 1260. The displacement vessel 1202
further includes arms 1238a and 1238b that are coupled to the drag
panel 1221 via hinges 1206a and 1206b such that each arm 1238a and
1238b may swing about the displacement vessel 1202. Arms 1238a and
1238b may be disposed on opposite sides of the drag panel 1221 from
one another. Arm 1238a houses a first control cable 1228a that
passes through central conduit 1213 and is stored within the
floatation device 1260. Arm 1238b similarly houses a second control
cable that may be stored within the displacement vessel 1202, such
within the floatation device 1260, for example. The control cables
are coupled to an anchor cable that is also coupled to a
directional converter and generator located at a stationary
location, such as land or a barge, as described above.
[0174] As also indicated above (e.g., FIG. 7D), the floatation
device 1260 may be separated into two or more compartments 1223a
and 1223b. The first compartment 1223a may be configured to be
waterproof and/or store equipment, such as a control mechanism 1220
configured to wind and/or release the control cable 1228a. The
control mechanism 1220 may comprise, for example, a motor, winch,
or a drum and a spring affixed to an axle. The second compartment
1223b may include a material to maintain buoyancy of the
displacement vessel 1202, such as a gas, for example, to increase
the buoyancy of the floatation device 1260. One of skill in the art
will hereby recognize that either compartment 1223a and 1223b may
be configured to store a material to maintain buoyancy of the
displacement vessel 1202 and/or house control mechanism 1220.
[0175] FIGS. 13A and 13B show a rendering of a displacement vessel
1302 having a drag panel 1321 with a parabolic shape. The
displacement vessel 1302 is substantially similar to the
displacement vessels described above and includes a drag panel 1321
supported by floatation devices 1360a and 1360b that are configured
to float at or near the surface of the water. The drag panel 1321
includes a first side 1321a and a second side 1321b that are
configured to capture drag forces more effectively than a flat drag
panel. In particular, the first side 1321a and the second side
1321b include a parabolic shape configured to capture drag forces
from the flow of water. One of skill in the art will recognize that
both sides 1321a and 1321b need not include the same shape. In one
example, the first side 1321a may include a parabolic shape while
the second side 1321b includes a flat surface, such as the flat
surface shown on displacement vessel 1202 sides 1221a and 1221b in
FIGS. 12A-12C. Because the drag panel can be rotated, operators can
select which side to face the direction of water flow and therefore
provide further adjustability and controllability of the
displacement vessel and thus also adjust or control electricity
generation.
[0176] FIGS. 14A and 14B show a rendering of a displacement vessel
1402 having a drag panel 1421 with an alternate surface shape. The
displacement vessel 1402 is substantially similar to the
displacement vessels described above and includes a drag panel 1421
supported by floatation devices 1460a and 1460b. The drag panel
1421 includes a first side 1421a and a second side 1421b configured
to capture drag forces more effectively than a flat drag panel. In
particular, the first side 1421a and the second side 1421b include
a lofted cut between two rectangular profiles. One of skill in the
art will recognize that both sides 1421a and 1421b need not be the
same. In an example, the first side 1421a may include a lofted cut
while the second side 1421b includes a flat surface, such as the
flat surface shown on displacement vessel 1202 sides 1221a and
1221b in FIGS. 12A-12C. In another embodiment, the first side 1421a
and/or the second side 1421b may include a concave surface.
[0177] FIG. 15A shows a top view and FIGS. 15B and 15C show a side
view of a layout for a tidal energy generation system 1500
comprising a displacement vessel 1502 and a directional converter
1509 positioned on a barge 1501 such as a work barge or spud barge,
for example. The tidal energy generation system 1500 includes a
directional converter 1509 positioned at or on a stationary
location that is a barge 1501 floating (or alternatively, fixed) at
or near the surface of the water 1518 as is known in the art. If
fixed at the surface of the water 1518, the barge 1501 may comprise
pylons that are driven into the bottom of the body of water (e.g.,
ocean, bay, or sea) and coupled to the barge 1501 itself to prevent
motion, such as motion due to waves at the surface of the water. In
another embodiment, the barge may include an anchoring system to
prevent the barge from drifting.
[0178] As described above, the directional converter 1509 is
coupled to an anchor cable that extends from the directional
converter 1509 to a displacement vessel in the water. The
displacement vessel may include any of the displacement vessels
described herein that are configured to capture energy from the
rise/fall of the water due to tidal action or drag forces from the
flow of water due to tidal action or other currents. The
directional converter 1509 may be similar to the directional
converters described herein and may include a drum 1513 and drive
gear 1512 positioned on an axle. The anchor cable 1503 is coupled
to the drum 1513 such that it may be wound/unwound upon the
rotation of the drum 1513. In an embodiment, a tensiometer 1534 may
be coupled to the anchor cable 1503 to provide data on the forces
exerted on the anchor cable 1503 to an operator. As described
above, the drive gear 1513 may be coupled directly (or indirectly
through a gear box) to one or more electrical power generators
1516a-1516c. The electrical power generators 1516a-1516c may
comprise one or more of any of the generators described herein,
such as for example, a 15 kW fixed magnet generator and/or a 100 kW
fixed magnet generator.
[0179] The directional converter 1509 may further include a reverse
control mechanism 1520 to rotate the drum and wind/unwind the
anchor cable, such as, for example, a motor or winch. Such a
control mechanism 1520 may be beneficial for winding the anchor
cable 1503 (and thus the displacement vessel) back to the barge
1501 for maintenance/repairs, among other benefits. The tidal
energy generation system 1500 may further include a hydraulic power
mechanism 1532 which may provide hydraulic power to any of the
components on the barge 1501 that may require hydraulic power, such
as, for example, the reverse control mechanism 1520. The tidal
energy generation system 1500 may further include a pivot frame
1536 to direct the anchor cable underneath the surface of the water
1518. The pivot frame 1536 may include one or more pulleys 1526a
and 1526b configured to redirect the anchor cable under the surface
of the water 1518.
[0180] In an embodiment, any of the tidal energy generation systems
described herein may include a level winder assembly 1548
configured to maintain a uniform wrapping of the anchor cable 1503
as it is wound around its respective drum 1513 by directing each
wrap of the anchor cable 1503 around the drum 1513 to sit tightly
next to the previous wrap. The level winder assembly 1548 may
include a guide mechanism that guides the anchor cable 1503 as it
is wound around the drum 1513 so that it is wound evenly across the
drum 1513. 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 1512 (and,
optionally, a gearing mechanism) such that one full rotation of the
drum 1513 causes the guide mechanism to travel a specified length
of the drum 1513 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 1513. After the
guide mechanism has traveled one full length of the drum 1513, 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 1548 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.
[0181] Additionally, the anchor cable 1513 may be configured to
approach the drum 1513 at an angle to improve cable life and
spooling operation (e.g., by preventing snags). In particular, a
distance D may be selected between the pulley 1536 and the drum
1513 such that the approach angle of the anchor cable, also known
in the art as fleet angle, is optimal for the particular assembly
setup. In an embodiment, the fleet angle may be between 0 degrees
and 15 degrees. In another embodiment, the fleet angle may be
between 0.25 degrees and 5 degrees. In yet another embodiment, the
fleet angle may be between 0.25 degrees and 1.25 degrees.
[0182] FIGS. 16A and 16B show a rendering of a tidal energy
generation assembly 1600 comprising a directional converter 1609
positioned at the base of a crane 1601. The crane may be positioned
at or on a stationary location, such as on shore or on a barge as
described with respect to FIGS. 15A and 15B. This embodiment may be
particularly useful for testing any of the displacement vessels
and/or directional converters described herein. The directional
converter 1609 may be substantially similar to any of the
directional converters described herein and may be mounted to the
base of the crane 1601 via a mounting frame 1642. A mounting frame
1642 may provide benefits such as easier swapping out of
directional converter prototypes for testing, among other benefits.
The directional converter 1609 may be coupled to an anchor cable
that extends along a boom 1640 of the crane, through a pivot frame
1636 affixed to an end of the boom 1640 (similar to the pivot frame
1536 described above), and out to a displacement vessel in the
water.
[0183] As stated above, the directional converter 1609 may be
substantially similar to the directional converters described
herein. In particular, the directional converter 1609 may include a
drum 1613 and a drive gear 1612 positioned on an axle such that
rotation of the drum 1613 winds/unwinds the anchor cable and
rotates the drive gear 1612. The drive gear 1612 may be coupled
directly (or indirectly through a gear box, for example) to one or
more electrical power generators 1616a-1616c via a connecting
mechanism, such as a chain, for example. Upon rotation of the drum
1613 and drive gear 1612, rotational energy is transferred to one
or more of the electrical power generators 1616a-1616c to thereby
produce electrical power. The generators 1616a-1616c may be
engaged/disengaged in a manner similar to that described above with
respect to FIG. 8. Each of the generators 1616a-1616c may comprise
any of the generators described herein, such as, for example, one
or more 15 kW fixed magnet generators and/or one or more 100 kW
fixed magnet generators.
[0184] In an alternative embodiment of the present invention, the
displacement vessels described above may be replaced with other
suitable mechanisms for capturing the ebb and flow of water due to
tidal action or other current flows while the generator is located
at the stationary location, such as land. Such mechanisms may
include a turbine having one or more propellers, rotors, or
impellors. Additionally, an array of turbines having one of the
previously described constructions may be used in place of the
displacement vessel. In any case, the turbines may be anchored to
or attached to the ocean/bay floor or may be floating at or near
the water surface via a floatation device as described in more
detail above. In another embodiment, the turbine may be mounted to
a barge, such as the spud barge as described above. The turbine may
be coupled to a drum that is under water (or alternatively above
water in the case that the turbine is floating at the surface of
the water) via a coupling mechanism such as, for example, a chain
or belt. The drum may be coupled via an anchor cable to a
directional converter such as the directional converters described
above. The directional converter may be positioned at or on a
stationary location, such as land or a barge, for example.
[0185] FIG. 17 illustrates a tidal energy generation assembly 1700
including a turbine 1750 coupled to a directional converter 1709
via an anchor cable 1703, similar to the embodiments described
above. The turbine 1750 may comprise one or more propellers,
rotors, or impellors that are adapted to capture forces exerted
thereon by the ebb and flow of water due to tidal action and/or
other currents. The turbine 1750 may be coupled to a drum 1713a via
a coupling mechanism, such as a belt or chain, for example. As the
flow of water causes the turbine 1750 to rotate, the coupling
mechanism causes the drum 1713a to rotate, thus winding or
unwinding the anchor cable 1703. The anchor cable 1703 may extend
along the bay/ocean floor, through a pulley 1726, and be coupled to
a drum 1713b that is associated with the directional converter
1709, thus causing the drum 1713b to rotate and unwind the anchor
cable 1703 from the drum 1713b. The directional converter 1709
works substantially similarly to the directional converters in the
above-described embodiments, and may be disposed on land 1706 at
any suitable distance away from the water. As the drum 1713b
rotates due to unwinding of the anchor cable 1703, rotational
energy is transferred to an electric power generator 1716 to be
converted into electrical power. The electrical power generated by
the generator 1716 may be stored in an electrical power storage or
transferred immediately to an electrical power grid.
[0186] Functionally, the turbine 1750 may operate similarly to an
"underwater windmill" and may be adapted to be anchored or attached
to the ocean/bay floor or, alternatively, float at or near the
surface 1718 of the water as described above. As water flows past
the turbine 1750, the propeller blades rotate cause a shaft to
rotate. The shaft may be coupled to drum 1713a around which an
anchor cable 1703 is wound. As the propeller blades of the turbine
rotate, the drum 1713a also rotates causing the anchor cable 1703
to be wound or unwound and thus transferring mechanical energy to
the directional converter 1709. As stated above, the directional
converter 1709 may be substantially similar to the directional
converters described above and may include a drum 1713b coupled to
the anchor cable 1703 and an electric power generator 1716. As the
anchor cable 1703 is wound by the turbine 1750, the drum 1713b
rotates and transfers mechanical energy to the electric power
generator 1716, which converts the mechanical energy into
electrical energy.
[0187] FIG. 18 illustrates a tidal energy generation assembly 1800
including a turbine 1850 mounted within a drag panel 1821 of a
displacement vessel 1802 and a directional converter 1809 mounted
on the displacement vessel 1802. The displacement vessel 1802 may
be substantially similar to any of the displacement vessels
described above, for example, in FIG. 5A-5D, 7C, 10, 11A-11E,
12A-12C, 13A-13B, or 14A-14B. As described above, the displacement
vessel 1802 may be connected to a stationary location, such as land
or a spud barge, for example, by control cables 1828a-1828d that
are coupled to an anchor cable 1803. One or more rewind assemblies
(not shown) may be housed at the stationary location to control the
winding of an anchor cable 1803 and alter (i.e., increase or
decrease) the distance of the displacement vessel 1802 from the
stationary location. The displacement vessel 1802 may also include
a power cable 1804 extending from the displacement vessel 1802 to
the stationary location to transmit electrical power to/from the
displacement vessel 1802.
[0188] Each control cable 1828a-1828d may be coupled to a
respective control mechanism that may be housed within or mounted
on the displacement vessel 1802 in compartments 1844a-1844c. The
control mechanisms may independently control the winding/unwinding
of the respective control cables 1828a-1828d to effectuate steering
of the displacement vessel 1802 in the water. The control
mechanisms may wind/unwind their respective control cables
1828a-1828d to adjust the orientation of the displacement vessel
with respect to the water/current flow, e.g., by adjusting the yaw,
pitch, and/or roll of the displacement vessel. For example, the yaw
of the displacement vessel 1802 may be adjusted using the control
cables to rotate the displacement vessel in a clockwise direction
in the water. In this example, control mechanisms in compartments
1844a and 1844c may wind up their respective control cables 1828a
and 1828c while control mechanisms in compartments 1844b and 1844d
may unwind their respective control cables 1828b and 1828d.
[0189] As described above, the control mechanisms may also be used
to control the amount of electricity generated. For example, by
rotating the displacement vessel 1802 to an angle away from the
direction of water flow, less drag force may be exerted on the drag
panel 1821 (and the turbine 1850) thus reducing the amount of
electricity generated by the electrical power generator 1816.
[0190] Similar to other embodiments described above, the
displacement vessel 1802 includes a drag panel 1821 extending
therefrom in a generally downwards direction. The drag panel 1821
includes a turbine 1850 mounted within the displacement vessel
1802. The turbine 1850 may be disposed on an axle and the axle may
be operably coupled (via a gearing mechanism or one or more
belts/chains, for example) to the directional converter 1809
mounted on the displacement vessel 1802. The directional converter
1809 may include an electric power generator 1816 that is operably
coupled to the turbine 1850 as described in more detail above. In
an embodiment, the displacement vessel 1802 may include two or more
turbines housed within the drag panel 1821.
[0191] In operation, the displacement vessel is positioned in the
water such that one side of the drag panel captures drag forces
cause by the flow of water due to tidal action (or other underwater
currents). As the water flows past the displacement vessel 1802,
the turbine 1850 captures drag forces from the flow of water and
converts the captured drag forces into rotational motion using a
series of angled blades (as are known in the art). The turbine 1850
transmits the rotational motion through a gearing mechanism, for
example, to the electrical power generator 1816 which then converts
the rotational motion into electrical power, as described in more
detail above. The electrical power may be transmitted through the
power cable 1804 to the stationary location, where it may be stored
and/or distributed to a power grid.
[0192] FIG. 19 illustrates a tidal energy generation assembly 1900
including a turbine 1950 directly mounted to the bottom of a
displacement vessel 1902. Similar to the embodiment shown in FIG.
18, the displacement vessel 1902 is connected to a stationary
location by control cables 1928a and 1928b that are coupled to an
anchor cable 1903. The anchor cable may be connected to a rewind
assembly (not shown) that is housed at the stationary location.
Each control cable 1928a and 1928b may be coupled to a respective
control mechanism located in compartments 1944a and 1944b that
independently wind/unwind each control cable to effectuate steering
of the displacement vessel. The displacement vessel 1902 may also
include a power cable 1904 connecting the displacement vessel 1902
to the stationary location to transmit power to/from the
displacement vessel 1902.
[0193] Similar to the tidal energy generation assembly of FIG. 18,
each control cable 1928a and 1928b may be coupled to a respective
control mechanism located in compartments 1944a and 1944b that may
be housed within or mounted on the displacement vessel 1902. The
control mechanisms may independently control the winding/unwinding
of the respective control cables 1928a and 1928b to effectuate
steering of the displacement vessel 1902 in the water. The control
mechanisms may wind/unwind their respective control cable 1928a and
1928b to adjust the orientation of the displacement vessel with
respect to the water/current flow, e.g., by adjusting the yaw,
pitch, and/or roll of the displacement vessel. For example, the yaw
of the displacement vessel 1902 may be adjusted using the control
cables to rotate the displacement vessel in a clockwise direction
in the water. In this example, control mechanism located in
compartment 1944a may wind up its respective control cable 1928a
while control mechanism located in compartment 1944b may unwind its
respective control cable 1928b.
[0194] In an optional arrangement, the displacement vessel 1902 may
include a turbine 1950 extending into the water from the bottom
surface of the displacement vessel 1902. The turbine 1950 may be a
standard underwater turbine as is known in the art. In another
embodiment, the turbine 1950 may be mounted to any suitable side of
the displacement vessel 1902. The turbine 1950 may be disposed on
an axle and the axle may be operably coupled (via a gearing
mechanism or one or more belts/chains, for example) to the
directional converter 1909 mounted on the displacement vessel 1902.
The directional converter 1909 may include an electric power
generator 1916 that is operably coupled to the turbine 1950 as
described in more detail above. In an embodiment, the displacement
vessel 1902 may include two or more turbines extending from the
displacement vessel 1902 into the water.
[0195] FIG. 20A shows an isometric view of an exemplary
displacement vessel 2002 with a drag panel 2021 and may be similar
to the displacement vessels of FIGS. 5A-5C, 7C, and 8-10, for
example. In particular, FIG. 20A shows a displacement vessel 2002
manufactured in modular components to facilitate transportation of
the displacement vessel 2002. The displacement vessel 2002 includes
first portion 2002a, second portion 2002b, and third portion 2002c
that may be manufactured separately and assembled together with the
drag panel 2021 to form the complete displacement vessel 2002. One
of skill in the art will recognize that a displacement vessel may
be manufactured out of any number of modular components to form a
complete displacement vessel. FIG. 20A also shows an underlying
structural frame of the drag panel 2021 (without a "skin" or
covering). The skin or covering may be, for example, sheet
metal.
[0196] The displacement vessel 2002 may further include one or more
compartments 2044a, 2044b, and 2044c. For example, compartments
2044a and 2044c may house control mechanisms, such as winches, that
are configured to wind/unwind control cables (not shown).
Compartment 2044b may house electronics to operate and/or batteries
to power the control mechanisms. The displacement vessel 2002 may
further include an antenna 2046 to facilitate communications with
an operator at the stationary location. The antenna 2046 may
transmit and/or receive data such as, for example, control signals
for the control mechanisms and video data from a camera.
[0197] FIG. 20B shows a side view of an exemplary displacement
vessel 2002 with a drag panel 2021. As illustrated in FIG. 20B, the
displacement vessel 2002 may include two or more control cables
2028a and 2028b where each control cable 2028a and 2028b is
connected to a respective control mechanism 2020a and 2020b
configured to wind/unwind its control cable. The control cables
2028a and 2028b may be further connected to an anchor cable and a
directional converter similar to the embodiments described
above.
[0198] FIG. 21A shows a tidal energy generation system 2100 that
includes a first displacement vessel 2102a at one end of an anchor
cable 2103 and a second displacement vessel 2102b at the other end
of the anchor cable 2103. The displacement vessels 2102a and 2102b
may be substantially similar to those displacement vessels
described above configured to capture drag (e.g., FIGS. 5A-5C, 7C,
10-14, and 20). In this embodiment (which may be particularly
useful where water flows in a single direction, such as in rivers,
for example), the first displacement vessel 2102a is released from
a directional converter 2109 housed at a stationary location 2106,
such as land. The first displacement vessel 2102a travels
downstream with the flow of water and generates electricity by
rotating a drum that is coupled to an electric generator in the
directional converter 2109 as described above. After the first
displacement vessel 2102a is released and travels downstream, the
second displacement vessel 2102b is released from the directional
converter 2109. The second displacement vessel 2102b also travels
downstream and generates electricity in the same manner as the
first displacement vessel 2102a. However, because the second
displacement vessel 2102b is connected to the anchor cable 2103,
the second displacement vessel 2102b pulls the first displacement
vessel 2102a back to the directional converter 2109 (i.e.,
upstream) as the second displacement vessel 2102b travels
downstream. FIG. 21B shows a snapshot in time where the second
displacement vessel 2102b has been released and has "rewound" the
first displacement vessel 2102a upstream back to the directional
converter 2109. During rewinding of either the first displacement
vessel 2102a (or the second displacement vessel 2102b), the
displacement vessel being rewound may be rotated such that the drag
panel is parallel to the flow of water to reduce drag during the
rewinding. This process of letting out one displacement vessel
while the other is rewound may be repeated any number of times to
generate electricity in any suitable body of water, such as a
river. It will be understood that in order to optimally cause a
displacement vessel to travel downstream and generate electrical
power, the drag panel 2121a of that displacement vessel 2102a is
oriented perpendicular to the river flow, while the drag panel
2121b of the other displacement vessel 2102b is oriented parallel
to the river flow, as illustrated in FIG. 21A.
[0199] FIG. 23A shows a displacement vessel 2302 having a rotatable
drag panel 2321.
[0200] In particular, the rotatable drag panel 2321 may be coupled
to and freely rotatable about a vertical axis of the displacement
vessel 2302 via an axle 2315. The axle 2315 may be coupled to a
control mechanism 2320, such as a motor, for example, that may be
configured to control the angle of rotation of the drag panel
2321.
[0201] FIG. 23B shows a displacement vessel 2302 having multiple
rotatable drag panels 2321a-2321c. In particular, the rotatable
drag panels 2321a-2321c may be coupled to and freely rotatable
about respective vertical axes of the displacement vessel 2302 via
axles 2315a-2315c.
[0202] Each axle 2315a-2315c may be coupled to a respective control
mechanism 2320a-2320c, such as a motor, for example, that may be
configured to control the angle of rotation of its respective drag
panel 2321a-2321c. 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.
[0203] Drag forces may be calculated for a single displacement
vessel 502 from the ebb and flow of the water due to tidal action.
As can be appreciated by one of skill in the art, the retractable
drag panel as described above may increase the area of the side of
the displacement vessel that experiences the drag forces, thus
increasing the energy captured. Eqn. 4 shows an equation for
calculating force on a side displacement vessel due to drag, where
F.sub.D is drag force, pr is density of the fluid, C.sub.D is
coefficient of drag, and A is the under-water area of the
displacement vessel, V.sub.W is the velocity of the water, and
V.sub.B is the velocity of the displacement vessel.
F.sub.D=0.5*p.sub.f*C.sub.D*A*(V.sub.W-V.sub.B).sup.2 (Eqn. 4)
[0204] Eqn. 5 shows an equation for calculating the power (P) of
the drag force on the displacement vessel.
P=F.sub.D*V.sub.B (Eqn. 5)
[0205] For example, assuming an underwater area of 660 ft.sup.2 for
the displacement vessel, a drag coefficient of 1.2, a density of
water at 20.degree. C. of 1.99 slugs/ft.sup.3, a water velocity of
12 knots, and a velocity of the displacement vessel of 2 knots, the
theoretical power generated by a single displacement vessel would
be about 1028 kW. Table 1 shows additional example calculations
(using Eqns. 4 and 5) of the theoretical power produced by a
displacement vessel utilizing a directional converter having a drag
energy converter as the water speed is varied between 4 knots and
12 knots.
TABLE-US-00001 TABLE 1 Ve- Velocity locity Velocity of Vessel of of
Relative Water Vessel to Water Drag Power V.sub.W V.sub.B V D P
Vessels/ knots knots ft/s knots ft/s lbs ft-lbs/s kW MW 12 2 3.4 10
16.9 224489 757792 1028 1.0 11 2 3.4 9 15.2 181836 613811 832 1.2
10 2 3.4 8 13.5 143673 484987 658 1.5 9 2 3.4 7 11.8 110000 371318
504 2.0 8 2 3.4 6 10.1 80816 272805 370 2.7 7 2 3.4 5 8.4 56122
189448 257 4 6 2 3.4 4 6.8 35918 121247 164 6 5 2 3.4 3 5.1 20204
68201 92 11 4 2 3.4 2 3.4 8980 30312 41 24
[0206] In another aspect of the present invention, the displacement
vessel 502 may include a rolling mechanism (not shown) to make more
efficient use of the drag forces on the displacement vessel. The
rolling mechanism is located on at least one surface of the
displacement vessel, such as a bottom surface of the displacement
vessel 502, and may comprise wheels, rollers, or a track. The
rolling mechanism may be connected to anchor cable 503, which
extends from the rolling mechanism to the anchor 508 attached to
the stationary location 506. When the ebb and flow of the tide
causes the displacement vessel 502 to drift in a lateral direction
relative to the stationary location 506, the anchor cable 503
engages the rolling mechanism, causing it to shift along the
surface of the displacement vessel 502. The rolling mechanism may
further be connected to an electrical power generator to power the
electrical power generator and generate electricity.
[0207] In another aspect, a method according to the invention
involves converting the lateral motion caused by the ebb and flow
of water due to tidal action into energy. The ebb and flow of the
water due to tidal action causes a body in the bay/ocean to drift
laterally and change its position with respect to a fixed location
on the seabed. This change in lateral distance may be converted
into rotational energy that is used to energize the electrical
power generator to generate electricity. Specifically, the method
of generating electricity from drag of the tides comprises the
steps of: providing a displacement vessel housing a directional
converter coupled to a generator, said displacement vessel being
directly above a stationary location; providing an anchor cable
having a first end and a second end, whereby said second end is
attached to said directional converter and said anchor cable
extends to an anchor secured at said stationary location, the
anchor cable having a first length between said directional
converter and said anchor; causing said displacement vessel to move
laterally from said stationary location and activating said
directional converter; and energizing said generator.
[0208] In another aspect, a method according to the invention
involves converting into energy the lateral motion of a
displacement vessel using an array of directional converters and
generators at a stationary location, such as land or a platform in
the ocean. The displacement vessel may be connected to the array of
directional converters via a plurality of anchor cables, and the
directional converters may be operatively coupled to a plurality of
generators. In this embodiment, the number of directional
converters outnumber the number of displacement vessel. The ebb and
flow of the water due to tidal action causes the displacement
vessel to drift laterally and change its position with respect to
the stationary location. The change in lateral distance causes the
anchor cables to exert forces on a multitude of directional
converters, which may be initiate rotational energy that is used to
energize the generators. Each of the generators may have a similar
or different electrical output rating. Accordingly, the use of one
displacement vessel provides power to a multitude of
generators.
[0209] Each directional converter and/or generator in the array may
be controllably operated to produce electricity based on
environmental factors such as, for example, the speed of the ocean
currents. In one example, when the currents become faster, the
method is capable of creating more energy by engaging a larger
number of generators, while when the current is slow, fewer
generators may be required to capture the kinetic energy of the
tides. In another example, when the currents become faster, the
method is capable of creating more energy by operating the
generators at a faster RPM, while when the current is slow, the
generators may be operated at a slower RPM (or disengaged
completely). In a typical tidal cycle, the speed of the ocean
currents generally resembles a sine wave. As an example, one
directional converter and generator may be engaged to produce
electrical energy as the tidal cycle begins and the speed of the
ocean currents is slow. As the tide changes and the magnitude of
the current speed increases, other directional converters and/or
generators may be engaged all at once or sequentially to produce
electrical energy. As the tide changes and the magnitude of the
current speed decreases, one or more directional converters and/or
generators may be disengaged. As another example, one or more
generators may be operated at a slower RPM, such as one that is a
quarter of the maximum rated RPM of the generator, to produce
electricity as the tidal cycle begins and the speed of the ocean
currents is slow. As the tide changes and the magnitude of the
current speed increases, the one or more generators may be operated
at a faster RPM to generate more electrical power from the ocean
currents.
[0210] Manufacture of Displacement Vessels
[0211] One of skill in the art will recognize that the displacement
vessel may be manufactured having any suitable dimensions or shape
to float at the water surface and/or capture the drag cause by the
ebb and flow of tidal action. Exemplary, but non-limiting,
dimensions for height, width, and length of a displacement vessel
or barge may range between 1 m and 100 m, with a volume ranging
between 1 m.sup.3 and 1,000,000 m.sup.3. The displacement vessel
may be manufactured using materials such as polymer (e.g.,
polyethylene terephthalate), concrete, cement, fiberglass, pumice,
steel, amorphous metal alloys, or other suitable materials.
Furthermore, the displacement vessel may be manufactured using any
suitable manufacturing technique such as injection molding, blow
molding, casting, joining, or 3D printing. An external surface of
the displacement vessel may provide an ecologically-friendly
environment for marine life so as to minimally disrupt ocean
organisms in their natural habitat. For example, the displacement
vessel may include a porous exterior surface structure that is
substantially similar or mimics a coral reef structure. A coral
reef structure may serve as a home to fish and other ocean-life to
integrate the tidal energy conversion assembly into the natural
environment. For example, a soft limestone surface such as that
described in U.S. Pat. No. 7,513,711 may be provided to allow
marine life to attach to the surface, the disclosure of which is
incorporated by reference herein. Additionally, a concrete surface
mixed with stones or rocks may be used to produce an irregular
surface similar to coral reef as described in U.S. Pat. No.
5,215,406, the disclosure of which is incorporated by reference
herein. The displacement vessel may be manufactured with a
corrugated hull such as described in U.S. Pat. Nos. 1,722,516;
1,808,599; and 3,126,557, the disclosures of which are incorporated
by reference herein. A corrugated hull may increase structural
strength by providing a greater resistance to buckling forces when
compared to a hull that is not corrugated (e.g., a flat sheet).
[0212] Furthermore, the displacement vessel may be manufactured in
any suitable shape, such as a box, cube, sphere, or cylinder
suitable for maintaining buoyancy and/or capturing drag caused by
tidal movements. The displacement vessel has a volume, and may
optionally be suitable for containing a fluid, e.g., a gas or
liquid. Depending on the type of material used, the thickness of
the walls of the displacement vessel may be varied as is known in
the art to maintain buoyancy and resist water pressure. Generally,
the wall thicknesses of the displacement vessel of the present
invention may be between 0.1 inch and 6 inches, but one of skill
will understand that any suitable thickness may be used to
withstand drag forces caused by the ebb and flow of tidal action or
hydrostatic pressure.
[0213] In one case, the displacement vessel may be constructed
underwater. In this case, a wall thickness of the displacement
vessel may be substantially thinner than the wall thickness
required if the displacement vessel was to be inflated at
atmospheric pressure. When inflated under water, the compression
pressure on the exterior of the displacement vessel is much greater
than the pressure on the exterior of the displacement vessel if it
was to be inflated at atmospheric pressure. When underwater,
depending on the depth of inflation, the displacement vessel would
expand to a smaller volume for an amount of fluid injected into the
displacement vessel as compared to expansion at atmospheric
pressure. Stresses within the displacement vessel wall due to the
inflation would be decreased due to the smaller strains in the
displacement vessel wall, thus allowing the walls to be
manufactured thinner than the thickness which would be required if
the displacement vessel was to be inflated at atmospheric pressure.
Nonetheless, the displacement vessel may be inflated with air or
another suitable gas or fluid while the displacement vessel is
under water. This process may allow for a manufacturer to save on
materials by producing displacement vessels using a smaller
quantity of raw input materials.
[0214] As alternative embodiments to the anchors shown in the
figures above, the anchor may be secured into the stationary
location, and may be constructed of any suitable shape such that it
would not be dislodged from the stationary location upon the
movement of the displacement vessel. The anchor may be constructed
such that an anchor cable may be threaded therethrough or permit an
anchor cable to be fixedly attached thereto. In one non-limiting
embodiment, the anchor may have a pointed end that is secured to a
stationary location and a looped end such that an anchor cable may
be added therethrough. The anchor may be composed of any customary
and suitable material, for example, steel, and/or concrete. The
anchor may also comprise a pulley mechanism that may be used to
reduce or minimize friction between the anchor cable and anchor as
the displacement vessel rises and falls with the tide and/or drifts
due to the ebb and flow of the water during tidal action. The
pulley mechanism may be particularly beneficial when an anchor
cable is connected to the displacement vessel, threaded through the
anchor, and connected to the directional converter, such as anchor
cables 103a-103c because friction between the anchor cable and
anchor may cause wear, and ultimately failure, of the anchor and/or
cable.
[0215] In another aspect of the invention, the tidal energy
conversion assembly may comprise a positioning system, for example,
a global position system (GPS) receiver, and associated logic
modules, such as computer processors, wherein the tidal energy
conversion assembly is capable of determining its current position
following the drift of the displacement vessel relative to the
position of the stationary location to which it is anchored. The
positioning system permits the tidal energy conversion assembly to
return to a position over the stationary location by winding the
anchor cable back into the spindle. The tidal energy conversion
assembly may comprise a bidirectional hydraulic winch for winding
the anchor cable and returning the displacement vessel back to a
position over the stationary location. In another embodiment, the
tidal energy conversion assembly may comprise a thruster, such as a
pump jet or hydraulic pump, to power the displacement vessel back
to a position over the stationary location. In another embodiment,
the logic modules of the tidal energy conversion assembly may be
programmed with locations where strong currents exist within a body
of water. The tidal energy conversion assembly may use this
information in addition to location information from the GPS to
direct itself, using a thruster and/or rudder mechanism, towards
the currents or maintain a specific location within currents to
generate electrical power.
[0216] In one aspect of the present invention, the electrical power
generator may also be coupled to an electricity storage component,
e.g., a battery, which may be housed within each displacement
vessel or at a central location. The electricity storage component
in each displacement vessel may be adapted to store up to any
suitable amount of electricity, for example, 1 to 10 MW, so long as
the buoyancy of the displacement vessel is maintained. The skilled
person understands that the electricity storage component may be
increased beyond 10 MW depending on the buoyancy of the
displacement vessel. The electricity storage component may be
configured to release the stored electrical energy at a desired
time. Furthermore, the electricity storage component may be coupled
to a motor within the displacement vessel. The motor may be
connected to the drive gear and be configured to wind up excess
slack in the anchor cable. [0210] In one embodiment, an ocean-going
freighter or barge may function as an on-site manufacturing
facility for the pumice-based displacement vessels. Pumice from
submarine volcanic activity may be collected by the freighter or
barge, processed on-site (e.g., 3D printed or molded) to form a
hollow displacement vessel, and coated with a polymer so that the
pumice does not waterlog. By manufacturing the displacement vessels
on-site, shipping costs, set-up time, and set-up expenses may be
significantly reduced. Additionally, larger displacement vessels
can be manufactured on the freighter since the vessels will not
need to be shipped to the operating site.
[0217] 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 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.
[0218] 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.
* * * * *