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.
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