http://www.columbiapwr.com/
Columbia Power Technologies, LLC
is an independent company founded in 2005 by Greenlight Energy
Resources, Inc. In partnership with Oregon State University, the
company is engaged in the development and commercialization
of wave energy harvesting devices using novel, off-shore,
direct-drive permanent-magnet generator topologies.
Greenlight Energy Resources, Inc. was formed by the principals of
the Greenlight Energy, Inc. (GEI) following the sale of their wind
energy company to BP Alternative Energy North America, Inc. (Press
Release) At the time of the sale in 2006, GEI was one of the
largest independent wind energy companies in the country with a
6,000 MW development pipeline comprised of large-scale wind energy
projects in 15 states. By year-end 2007, over $700 million of wind
energy facilities developed by GEI were operational, including a
$500 million facility in Colorado being completed this year by BP.
Columbia’s management team combines energy industry, engineering,
legal, and technology commercialization experience, and is well
prepared to be a leader in the field of ocean energy.
Technology
Columbia is developing technologies that will generate energy
between one and three miles offshore - where the available wave
energy is greatest. We believe that
direct drive systems, which avoid the use of pneumatic
and hydraulic conversion steps, are more efficient, more
reliable and easier to maintain, and are therefore the most
likely to deliver the lowest cost of energy. Our research
path focuses on:
Point absorbers
Direct coupling of the wave
motion to the generator
Innovative use of permanent
magnets and other highly-efficient components
Reducing the number of moving
parts
Minimizing the number of
conversion steps and associated losses
Having completed tank testing at OSU, Columbia Power has deployed
an intermediate scale prototype near Seattle and code named
SeaRay. The device is tuned to the Puget Sound environment and is
controlled remotely from Corvallis Oregon. Sea trials (click
here for video) will continue through the spring of 2011. :
http://www.youtube.com/watch?v=B56-Vt5h004&feature=player_embedded
Contact --
Oregon Location
Columbia Power Technologies, Inc
4920A SW 3rd Street
Corvallis, OR 97333
Phone Main: (541)368-5033
Fax: 541 230 1498
Virginia Location
Columbia Power Technologies, Inc
236 East High Street
Charlottesville, VA 22902
Phone
Main: 434 220 7590
Fax: 434 220 3712
General Email Inquiries
info@columbiapwr.com
http://www.businesswire.com/news/home/20110308006644/en/Columbia-Power-Technologies-Secures-Governmental-Private-Funding
March 08, 2011
Columbia Power Technologies Secures Governmental and
Private Funding, Deploys Wave Power Device in Puget Sound
First deployment signals
major milestone
CORVALLIS, Ore.--(BUSINESS WIRE)--Columbia Power Technologies,
Inc. (www.columbiapwr.com), a leading renewable energy company in
Oregon that is commercializing its wave energy conversion
technology, has successfully deployed its first SeaRay prototype
in Puget Sound. These sea trials represent a key milestone in
moving from the pre-commercial stage toward commercial viability.
Additionally, the closing of Columbia Power’s recent private
capital signifies excellent validation of the company’s vision and
technical development capabilities.
“Our task is to demonstrate to utilities and independent power
producers that we can help them deliver power predictably,
reliably, and at a cost that is competitive. At this stage, we are
making this happen in a very rapid and capital-efficient manner.”
“The clear progress we have made in our technology readiness has
been accomplished as a result of an outstanding team of engineers
and partners,” said Bradford Lamb, president and COO of Columbia
Power Technologies, Inc. “With the support of the U.S. Department
of Energy, the U.S. Navy, and the Oregon Congressional Delegation
and by following a disciplined technology development roadmap, we
are able to accelerate our commercialization path.”
The device, code-named SeaRay, represents
the first wave power technology of
its kind and is capable of extracting up to twice the amount of
energy from ocean waves compared with other technologies under
development. Additionally, this unique design is able to produce
power in adverse sea conditions, allowing higher and more energy
conversion throughout the year. Columbia Power
Technologies’ goal is to deliver megawatt-scale devices, capable
of operating in the widest range of temperate zone coastal load
centers around the globe.
“The SeaRay is performing beyond our expectations and tracking
well with modeling predictions,” said Reenst Lesemann, CEO of
Columbia Power Technologies. “Our task is to demonstrate to
utilities and independent power producers that we can help them
deliver power predictably, reliably, and at a cost that is
competitive. At this stage, we are making this happen in a very
rapid and capital-efficient manner."
Columbia Power Technologies’ vision was to develop a simpler, more
reliable and more efficient device — the SeaRay accomplishes this
through its
heave- and
surge-energy capture design, accessing the full potential
of the wave. This innovative approach is a breakthrough in wave
energy technology because it can survive and produce electricity
in extreme weather conditions, is more dependable, and is easier
to maintain, all the while generating a
smaller environmental footprint than other
renewable energy solutions. To see the SeaRay in action, please
visit: http://www.snipurl.com/searay
The world’s oceans are estimated to contain enough practically
extractable energy to provide over 6,000 terawatt hours of
electricity each year, which is enough to power over 600 million
homes and is worth over $900 billion annually.
About Columbia Power
Technologies, Inc.
Columbia Power Technologies, Inc., is an emerging leader in the
wave power industry. The company is commercializing a
third-generation wave energy device using novel direct-drive
permanent-magnet generator technologies. The company's design
philosophy emphasizes survivability and simplicity with an ability
to deliver energy at a competitive cost. Founded in 2005 with
technology licensed from Oregon State University, the company is a
member of the Greenlight Energy Resources, Inc., family of
renewable energy companies and has primary R&D facilities and
operations in Corvallis, Oregon, with administrative support in
Charlottesville, Virginia.
http://www.earthtechling.com/2011/03/oregon-wave-power-start-up-goes-prototype/
March 12th, 2011
Oregon
Wave
Power Start Up Goes Prototype
by
Caleb Denison
Video :
http://www.youtube.com/watch?v=B56-Vt5h004&feature=player_embedded
WO2010096195
DIRECT DRIVE ROTARY WAVE
ENERGY CONVERSION
2010-08-26
Inventor(s): RHINEFRANK KENNETH [US]; LAMB BRADFORD [US]; PRUDELL
JOSEPH [US]; SCHACHER ALPHONSE [US] + (RHINEFRANK, KENNETH, ;
LAMB, BRADFORD, ; PRUDELL, JOSEPH, ; SCHACHER, ALPHONSE)
Applicant(s): COLUMBIA POWER TECHNOLOGIES [US]; RHINEFRANK KENNETH
[US]; LAMB BRADFORD [US]; PRUDELL JOSEPH [US]; SCHACHER ALPHONSE
[US] + (COLUMBIA POWER TECHNOLOGIES, ; RHINEFRANK, KENNETH, ;
LAMB, BRADFORD, ; PRUDELL, JOSEPH, ; SCHACHER, ALPHONSE)
Classification: - international: F03B13/12 - European: F03B13/20;
Y02E10/38
Also published as: US2010213710
Abstract -- An apparatus
and method for converting wave energy using the relative
rotational movement between two interconnected float assemblies
and the relative rotational movement between each of the float
assemblies and a spar which extends from a connection with the
float assemblies at the water surface into the water.
Background of Invention
[0002] The present invention relates to the extraction of energy
from water waves found in oceans or other large bodies of water
and, in particular, the conversion of wave energy into electrical
energy. Water waves that form in large bodies of water contain
kinetic and potential energy that the device and methodology of
the present invention is designed to extract. More specifically,
the object of the present invention is to provide structures and
methods to efficiently convert the hydrodynamic surge (horizontal
component) and heave (vertical component) of ocean wave energy
into rotary shaft motion for use in direct drive rotary
generation.
Summary of Invention
[0003] We describe a unique approach for converting wave motion to
mechanical rotary motion. A wave energy converter (WEC) that
extracts energy from both the heave and surge energy contained in
an ocean wave so as to allow for twice the energy extraction
potential of other systems that only extract energy from heave
motion in the waves. [0004] We also describe a wave energy
converter that provides a wave to rotary energy . approach that
will work with a DDR generator or any other power take off (PTO)
driven by a mechanical rotary drive shaft. The system may allow,
but is not limited to, the use of large diameter, high torque and
low speed direct driven rotary (DDR) generators in wave energy
applications and may allow for a more cost effective and efficient
conversion of wave energy as compared to other methods of
conversion. [0005] We also describe a method by which the ocean
wave forces can be coupled to create low speed high torque
rotation. This rotation can then be coupled to the DDR generator
or other PTO. This PTO may include all forms of rotary power
conversion, such as a large direct driven rotary electric
generator, a gear box driven electric generator, a belt driven
electric generator, water pumping systems, water desalination,
pneumatic pumping systems and even hydraulic pumps, and similar
devices.
[0006] The structure and methodology includes mechanical
implementations that, among other things, allow for an increase in
the rotary speed of the main drive shaft. They also provide for
methods of implementation that increase the magnetic flux velocity
in the generator air gap.
Brief Description of Drawings
[0007] The invention will become more readily appreciated by
reference to the following detailed descriptions, when taken in
conjunction with the accompanying drawings, wherein:
FIG. 1 is an isometric view of a
wave energy converter;
FIG. 2 is a representational
drawing of an ocean wave;
FIG. 3 is a cross-sectionaLview
of an example wave energy converter;
FIGS. 4A-4C are isometric views
of an example wave energy converter;
FIG. 5 is an isometric view of an
example wave energy converter;
FIG. 6 is an isometric view of an
example wave energy converter;
FIG. 7 is a cross-sectional view
of fore and aft floats showing exemplary connecting bearing
shafts;
FIG. 8 is a partial cut-away view
of an embodiment of an example wave energy converter;
FIG. 9 is an isometric view of an
embodiment of an example wave energy converter;
FIG. 10 is an isometric view of
an example wave energy converter;
FIG. 1 1 is a side view of an
embodiment of the wave energy converter of the present
invention;
FIG. 12 is an isometric view of
an example wave energy converter;
FIG. 13 is an isometric view of
an example wave energy converter;
FIG. 14 is a partial isometric
view of the present inventions;
FIG. 15 is an isometric view of
an example wave energy converter;
FIG. 16 is an isometric view of
an example wave energy converter;
FIG. 17 is an isometric view of
an example wave energy converter;
FIG. 18 is a partial isometric
view of an example wave energy converter; and
FIG. 19 is an isometric view of
an example wave energy converter.
Detailed Description of
Invention:
[0010] A wave energy converter 10, shown in FIG. 1, is comprised
of a fore float 11 and an aft float 12. These floats 1 1, 12 are
rotably attached to spar 13. The floats 1 1, 12 are attached
through drive, shafts 18 and 19 (shown in FIG. 3) to a mechanical
rotary system that utilizes the speed or torque to perform
mechanical work (electric generation, water pumping, or similar
function). As seen in FIG. 1, the outer body is comprised of three
components: the spar 13; the fore float 11; and the aft float 12.
The floats 11 and 12 are connected together by bearing shafts 16
and 17 (the latter of which is shown in FIG. 3) such that fore
float 11 and aft float 12 can rotate relative to each other.
[0011] Water waves 20 are comprised of rotational particle motions
that are grossly depicted in FIG. 2, heave, which creates vertical
up force 21 and vertical down force 22 on bodies exposed to the
wave, and surge which creates horizontal force 23, that a wave
imparts to a body. The magnitude of the rotational forces 22 and
23, depicted in FIG. 2, are highest at the water's surface, and
diminish as the water depth increases. The floats 11 and 12 of
FIG. 1 experience vertical forces due to the heave of wave 20.
[0012] In FIG. 3, the floats 11 and 12 interconnect through
bearing shafts 16 and 17 so as to permit relative movement between
them. Driveshaft 19 connects float 11 to driveshaft flange 31 by
passing through a motor housing 30 mounted to the top of spar 13.
Rotation between the driveshaft 19 and motor housing 30 is
accommodated by a sealed spar bearing 33. The sealed spar bearing
33 permits rotation of driveshaft 19 relative to housing 30 but
keeps water out of the motor housing 30. In similar fashion,
driveshaft 18 connects float 12 to driveshaft flange 32 by passing
through motor housing 30. Rotation between the driveshaft 19 and
motor housing 30 is accommodated by sealed spar bearing 34, which
also seals the housing 30 so as to keep out water. Driveshaft
flange 31 is mounted to a stator assembly of a generator and
driveshaft flange 32 is mounted to a rotor assembly of a
generator. Alternatively, driveshaft flanges 31 can connect to a
rotor assembly of a first generator and driveshaft flange 32 can
connect to a rotor assembly of a second generator, with the stator
of each being fixedly mounted inside motor housing 30. In one
embodiment, two 80 ton generators are employed.
[0013] As shown in FIG. 3, the float surface area is maximized by
staggering the fore float 1 1 and aft float 12 about an axis of
rotation. The bearing shaft 17 and bearing shaft 16 of FIG. 3 are
axis centric on opposite sides of wave energy converter 10. The
placement of these bearing shafts allow for only relative
rotational motion about the axis between the fore float 11 an aft
float 12. While this approach of coupling the fore float 11 and
aft float 12 with a bearing system that is independent of the spar
is not essential for function of the system, it allows for
reduction of forces on the spar bearings 33 and 34. [0014] The
spar heave plate 14 shown in FIG. 1 is exposed to smaller heave
forces due to its depth below the water surface. The placement of
that plate below the surface encourages the spar 13 to remain
relatively stationary in the vertical direction and resist the
vertical motion of the floats 11 and 12.
[0015] A Power Take Off (PTO) can be mounted in the spar 13 or
floats 11 and 12, and may be mounted in any location as
appropriate for the specific design considerations. A first and
second direct drive rotary generation PTO 35 and 36 are shown in
FIG. 8, but any mechanical power transfer system such as a DDR
generator (previously mentioned), a gear box driven electric
generator, a belt driven electric generator, water pumping
systems, water desalination, pneumatic pumping systems, even
hydraulic pumps, or similar can be used.
[0016] In one embodiment, the first PTO 35 is connected to drive
shaft 19 through flange 31. The second PTO 36 is connected to
drive shaft 18 through flange 32 (not shown in FIG 8). The
relative rotational motion between the spar 13 and the floats 1 1
and 12 drives the first and second PTO to convert wave motion to
useable power. As described earlier, the pitching action of the
spar (surge energy) and the pitching action of the float (heave
energy) are combined to create a net sum that is complementary and
produces a combined speed and force that is greater then the
individual float or spar energies. This net energy is transferred
to the PTO to perform work such as electrical generation, water
pumping, air pumping, or similar effort.
[0017] In another embodiment, a single PTO can be connected to
drive shafts 18 and 19, such that a rotor (not shown) is attached
to the fore float 1 1 and the stator is attached to the aft float
12 (or visa- versa). The heave motion of this system creates
relative rotational motion between the floats 11 and 12. By
connecting the PTO only between the floats, the only energy
captured is the energy from the relative motion between the
floats. Hydrodynamic modeling has shown that the motion between
the floats is increased by the addition of the spar system and its
contribution of pitch heave response on the float bodies. However,
an advantage to this arrangement is the increased rotary speeds
and reduced generator costs. Because the stator and rotor are both
. turned in opposite directions by the float motion, the relative
speed between the rotor and stator is twice that of a spar mounted
stator. It is well known in the art of generator design that
increased speed, in general, allows for reduced cost.
[0018] In another embodiment, two PTO' s can be mounted within
housing 30, or mounted on the surface outside of the spar, encased
in a water tight enclosure on the port and starboard sides of the
system as shown in FIG. 9. In this second arrangement, PTO 37 has
a rotor (not shown) attached to one float 11 and a stator (not
shown) attached to the other float 12. The reverse is true of the
PTO 38, which has a rotor (not shown) attached to float 12 and a
stator (not shown) attached to float 11. Both PTO's are driven by
the relative motion between the floats 11 and 12. The same
advantage of increased generator speed is realized between stator
and rotor, because each is being rotated in opposite directions.
[0019] FIGS. 4A-4C depict various positions of the floats 11 and
12 relative to each other and relative to spar 13 as different
wave conditions are encountered by the wave energy converter 10.
More specifically, FIG. 4A shows a situation in which the spar 13
is essentially perpendicular to the horizon and float 11 and float
12 have rotated downward. In FIG. 4B, floats 1 1 and 12 have
rotated about bearing shaft 16 so as to be roughly horizontal
while spar 13 has rotated off of the vertical position. In FIG.
4C, float 11 has rotated clockwise, above the horizon, float 12
has also rotated clockwise, but to an angle below the horizon,
while spar 13 has rotated counterclockwise about seal bearings 33
and 34. The movement of floats 11 and 12 and spar 13 being in
reaction to wave forces acting upon them, with each movement
leading to the potential conversion of wave energy by wave energy
converter 10. Floats 11 and 12 will rotate up and down with each
wave's incoming crest and trough, experiencing rotational motion
with respect to the spar 13 due to heave forces acting on the
floats.
[0020] The floats 11 and 12 of FIG. 1, experience horizontal
forces 21 and 22 due to wave surges shown in FIG. 2. The floats 11
and 12 are allowed to rotate with respect to the spar 13. Figure
4B depicts the floats 11 and 12, and spar 13 being pulled by surge
forces to the right. The surge forces are minimal at the bottom of
the spar 13 and at the heave plate 14. This difference in
horizontal loading between the top of spar 13 and the bottom of
that spar causes a moment about the spar body, so as to cause the
spar to pitch right as depicted in FIG. 4B. The system is
ballasted and designed to achieve a desired pivot point 15 on spar
13, this pivot point affects the speed of the pitching action and
the amount of power absorbed. The optimization of this pitching
action is the designers' prerogative based on design priorities
upon reading and understanding this disclosure, but ideally the
pivot point 15 is between the motor housing 30 but above the heave
plate 14. As the spar 13 pitches fore and aft, the spar 13 and
floats 11 and 12 experience relative rotational motion.
[0021] In both cases, surge and heave forces/the floats 11 and 12
rotate about spar 13 with speed and torque to transmit power
through drive shafts 18 and 19. The net affect of these heave and
surge driven rotary motions is hypothesized and numerically
modeled to be complementary (not opposing) in direction and force.
The synthesis of these two motions is depicted in FIG. 4C, where
it is shown that the net effect of both heave and surge forces
will act on the wave energy converter 10 and that converter will
absorb power from both modes (heave and surge) of wave motion. The
system may work in either mode of operation to capture energy by
using heave motion or surge motion as depicted, or both.
[0022] As an electrical generating system, a reduced cost of
energy (CoE) is expected to be an advantage over other approaches.
The wave energy absorber has the potential to be half the size of
a competing wave energy converter of the same power rating. That
size reduction reduces capital costs and CoE. The CoE is further
reduced by reducing the capital expenditure of the generator by
optimizing the electromagnetic design using a large diameter
generator when low-speed high-torque rotary motion is employed.
Operating and maintenance costs are reduced by the systems
operational design; there are minimal moving parts, and the parts
that do move do so fluidly, with the incoming waves, so as to
reduce the affect of snap loading often experienced by marine
deployed bodies. This construction and approach reduces repair
time and cost. The speed of rotation and driving torque are both
increased by the extraction of both heave and surge energy. r
Increasing the speed of body motions helps to reduce generator
capital costs and the system components may be designed to satisfy
this priority. In some methods described in this disclosure,
reliability is improved by the elimination of all intermediate
conversion stages. The WEC Survivability is another advantage of
this system. The combined effect of the design results in a fluid
motion of the wave converter in the ocean which reduces structural
loading, reduces mooring loading, and accommodates for tidal
variation.
[0023] These methods described utilize rotary motion from a WEC to
allow for a point absorber design that captures the heave and
surge energy components of the incoming wave energy. By capturing
both the surge and heave component, the maximum possible energy
capture width of the wave energy device is [lambda]/[pi] (where
[lambda] = wave length) as compared to [lambda]/2[pi] for a device
that captures only the heave component. This improvement in
capture width is expected to reduce the size and cost of the wave
energy converter. The exact generator, pump, or rotary mechanisms
for this application is not essential to the claims of this
invention because it is applicable to any mechanism or system that
is driven by a rotary shaft.
[0024] In FIGS. 5 and 6, the spar 13 is shortened and the damper
plate 9 is connected to the spar 13 using a cable or chain 31. The
shortening of the spar allows for increased pitch motion and
increased relative speed between float and spar in the surge mode
of operation. The heave plate 14 connected through the cable 31
still allows for heave reaction force in the heave mode of
operation and allows the damper plate 9 to be lower in the water
to increase the effectiveness of the damper plate operation. A
shorter spar 13 also reduces the overall system cost, optimization
of power absorption, and optimization of PTO speed, lowers the
damper plate position and increases heave response. [0025] The
spar 13 is designed to be relatively fixed in heave so that it
resists the upward and downward heave motion of the floats. The
spar 13 may also be designed such that it has a ballast chamber
that varies the spar buoyancy between either positively buoyant
when the wave trough is above the spar, or negatively buoyant when
the wave crest is above the spar. Spar 13 is designed to
transition between positive buoyancy and negative buoyancy, while
maintaining the buoyancy to avoid sinking. This condition causes
the heave motion of the spar 13 to move opposite (180 degrees out
of phase) to the heave motion of floats 11 and 12. This diving and
rising spar design is accomplished using a compressible ballast
chamber in the lower section of the spar (not shown). When the
wave crest is over spar 13, the higher pressure from the wave
causes the ballast chamber to compress and causes the spar 13 to
sink until the floats reach equilibrium buoyant state. Conversely,
when the wave trough is over spar 13, the pressure on the buoyancy
chamber is reduced, the ballast chamber expands, and spar 13 rises
until the floats 11 and 12 reach an equilibrium buoyant state with
the spar 13. This diving and rising action amplifies the range of
motion between floats 11 and 12 and spar 13, and can be used to
improve the wave converter performance. Additionally, it has been
shown that proper ballast location in the spar can increase
captured power and can also be used to optimize relative speed
between the spar and floats.
[0026] A challenge to proper operation of this system is the
control of directionality. The power extraction efficiency is
improved by proper orientation of floats 11 and 12 and the
rotation axes with respect to the incoming wave front. Generally,
performance is maximized when the axis of rotation is parallel to
the incoming wave front, and minimized when the axis of rotation
is perpendicular to the incoming wave front. Depending on the
incident wave energy the system performance can be optimized and
stabilized by changing the float orientation with respect to the
incoming waves. It is recognized that in very energetic sea
states, it may be desirable to decrease performance by changing
the float orientation to a less efficient position.
[0027] Directionality is affected by direction of water flowing
past the device. The mean drift current of the incident wave
climate is one source of current flow acting on the buoy. Another
source of water flow acting on the body is the predominant ocean
current acting on the buoy body. Wind acting on the buoy body
above the water surface will also affect directionality.
Directional vanes 39, shown in FIG. 10, can be used to channel
water on the underside of floats 1 1 and 12. These vanes can be
installed on the fore float 11, the aft 12, or both, depending on
the preferred affect. Directional vanes 39 will cause floats 11
and 12 to align with the direction of flow acting on them. As
depicted in FIG. 10, the directional vanes 39 are shrouded by the
outer hull of the floats. By shrouding the directional vanes 39,
the directional effects from the wave action will be increased due
to the wave acting from under the float body, while the effects
from ocean current will be minimized. The size, length and aspect
ratio of the directional vanes 39 may be varied to increase or
decrease the magnitude of the effect of the vanes on
directionality. Directional vanes 39 can alternatively be used on
the aft float 12 only to provide a rudder effect to keep the
device pointed into the wave.
[0028] In another embodiment, a rudder 40, shown in FIG. 11 can be
used to control float orientation in the wave. More than one
rudder may also be used. The rudder may be positioned in all 360
degrees of rotation. The rudder is statically positioned, manually
controlled, or automatically controlled using existing technology
similar to an automatic pilot used on numerous vessels. The
control for the rudder takes into account the prevailing wave
direction, prevailing currents, wind, and drift and sets the
rudder to maintain the desired buoy direction.
[0029] In another embodiment, a two point mooring system is used
to control directionality. This system may be slack moored as
depicted in FIG. 12. In FIG. 12, a slack mooring line 41 attaches
to bearing shaft 16 and a second mooring line 42 attached to
bearing shaft 17. A mechanism such as a chain winch 43, shown in
FIG. 14, can be used to shorten or lengthen either mooring line.
This will create a rotation on the float such that can be oriented
in the desired direction.
[0030] In another embodiment, a three point mooring system is used
to control directionality. This system may be slack moored as
depicted in FIG. 13. Mooring lines 41, 42 and 44 can attach to the
heave plate 14 of converter 10 by conventional means. In one
embodiment, mooring lines 41 and 42 form a common connection point
to the heave plate 14 through a chain winch 43 as shown in FIG.
14. By adjusting the direction of chain as shown in FIG. 14, the
heave plate 14 can be forced to rotate into the desired direction
so as to orient the converter 10 in the desired direction.
[0031] In another embodiment, the top surface area of float 1 1
and float 12 in FIG. 1 are covered with an array of solar panels
52 and 53. This is of particular interest due to the large and
un-blocked surface area that is in direct line of sight with the
sun. Complementing the wave power with solar power provides for a
more continuous power delivery from each WEC especially when wave
energy is low during summer months.
[0032] The geometry of system components can be optimized for use
on different bodies of water during different seasons based on
many factors. The floats 11 and 12 may be constructed with a
narrow width to length ratio, or it might have a wide aspect
ratio. Float geometry is optimized for wave height, wave period,
seasonal wave spectral density, power capture, and directionality
considerations. Float shape is not limited by the geometry
depicted and may take on a more curved disc shape. The floats 1 1
and 12 might also be cylindrical or rectangular in shape.
Similarly, the diameter or length of the spar 13 may be altered
for performance enhancements.
[0033] Depending on the wave conditions, for example the distance
between a wave peak and a wave trough, it may be advisable to
separate floats 11 and 12, using adjustable arms as shown in
FIG.17, alter the shape of the floats as shown in FIG. 16,
re-orient the floats as shown in FIG. 17 and FIG. 18, add
additional damper plates as shown in FIG. 19, or, in shallower
waters, embed the spar in the sea floor.
[0034] With regard to FIG. 16, it should be noted that the side
profile of floats 11 and 12, shown here as a tear-dropped shape,
can be mounted to arms 47 and 48, respectively, such that they can
rotate about of center axis of the arms. The shape of the float is
not limited. Float shape is to be optimized for hydrodynamic
performance. These floats can include cylinders, squares,
triangles and any combinations of curves. Nor is the rotation axis
limited, but can be varied. The rotation of the floats changes the
hydrodynamic performance, including water plain stiffness of the
float, the float's center of gravity, and float free-board.
Variable ballasting of floats 1 1 and 12 could provide additional
hydrodynamic optimization.
[0035] As shown in FIG. 17, the length of arms 47 and 48 can vary
to suit the water conditions or to control the amount of energy
being absorbed. In this embodiment of a wave energy converter,
floats 11 and 12 are rotably connected to arms 47 and 48,
respectively, via mounting 49 and 50, respectively. The yaw
rotation of the floats allows the floats to rotate so as to be
perpendicular to the axis of rotation of the PTO in housing 30.
The floats can also rotate on arms 47 and 48 so as to be parallel
with the axis of rotation of that PTO, or somewhere in between the
parallel and perpendicular positions. Indeed, the orientation of
the two floats can differ as shown in FIG. 17. The floats can be
automatically or manually adjusted to control the amount of energy
being absorbed from a wave.
[0036] As shown in FIG. 18, it is also possible to add a rudder 51
to the bottom of heave plate 14 in lieu of, or in addition to,
directional vanes 39 of FIG. 10, rudder 40 of FIG. 11, or a
combination of the two. Rudder 51 may be automatically or manually
positioned to control the direction of the wave energy converter
relative to the direction of wave travel. [0037] As shown in FIG.
19, it is also possible to suspend a damper plate 52 from heave
plate 14 to stabilize spar 13. For the same reason, it is also
possible to suspend a damper plate 52 from damper plate 9, or a
second heave plate (not shown) from heave plate 14, or a
combination of these plates to stabilize the operation of the wave
energy converter of the present invention.
[0038] As can be readily understood from the foregoing description
of the invention, the preferred structure and method of operation
have been described, but other structures and approaches can be
substituted therefore without departing from the scope of the
invention.
