WO2015175535A1

WO2015175535A1 - Components for hydroelectric turbines

Info

Publication number: WO2015175535A1
Application number: PCT/US2015/030373
Authority: WO
Inventors: Daniel E. POWER; Ned HANSEN
Original assignee: Oceana Energy Company
Priority date: 2014-05-13
Filing date: 2015-05-12
Publication date: 2015-11-19

Abstract

A hydroelectric turbine may include a stator comprising an electricity generating portion having coils and a rotor supported relative to the stator and configured to rotate relative to the stator about an axis of rotation. The turbine may also include a plurality of magnets arranged so as to generate electricity in the coils as the rotor rotates relative to the stator. The turbine may further include a plurality of first blade portions and second blade portions supported on the rotor. Each first blade portion may be radially outside of a circumference of the rotor and each second blade portion may be radially within the circumference of the rotor. Each blade portion may be angled in a tangential direction and angled downstream in an axial direction.

Description

COMPONENTS FOR HYDROELECTRIC TURBINES

CROSS-REFERENCE TO RELATED APPLICATION

[001] This application claims priority to U.S. Provisional Patent Application No.61 /992, 796, filed May 13, 2014 and entitled "Components for Hydroelectric Turbines," the entire content of which is incorporated by reference herein. TECHNICAL FIELD

[002] The present disclosure relates generally to turbines, and more particularly, components for hydroelectric turbines.

INTRODUCTION

[003] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described in any way. [004] A hydroelectric turbine can be used to generate electricity from the current in any moving body of water (e.g., a river or ocean current) or fluid source. Electricity generation using such turbines (which convert energy from fluid currents) is generally known. An example of such a turbine is described, for example, in U.S. Publication No. 2012/021 1990, entitled "Energy Conversion Systems and Methods," which is incorporated by reference in its entirety herein. Such turbines can, for example, act like underwater windmills, and have a relatively low cost and ecological impact. In various hydroelectric turbines, for example, fluid flow interacts with blades that rotate about an axis and that rotation is harnessed to thereby produce electricity or other forms of energy.

[005] The hydrokinetic industry's focus, however, has to date largely been on tidal power, or deploying such hydroelectric turbines in tidal basins to exploit the movement of water caused by tidal currents (i.e., the rise and fall in sea levels due to tides). Although the potential for power generation is great in such deployments, which may maximize total overall collection of flow energy from the ebb and flow of the two-directional flows found in tidal basins, the application of hydrokinetics to rivers can also have a significant impact, such as, for example, on populations living near swift flowing rivers.

[006] River hydroelectric turbines can, however, pose various challenges related to the turbulent nature of the one-directional (i.e., uni-directional) river flow, which produces non-steady input/output and can accelerate fatigue issues. Furthermore, various additional challenges may arise with regard to protecting such turbines from floating debris carried by the river, and supporting and anchoring such turbines within the river.

[007] It may, therefore, be desirable to provide a hydroelectric turbine having a configuration and blade design suited for the uni-directional flow of a river, which is also easily reconfigured to adjust for the widely variable speeds of river currents. It also may be desirable to provide a blade design that may deflect debris away from the turbine structure. It may further be desirable to provide a support structure to anchor the turbine in a stationary position within a river.

SUMMARY

[008] The present disclosure solves one or more of the above-mentioned problems and/or achieves one or more of the above-mentioned desirable features. Other features and/or advantages may become apparent from the description which follows.

[009] In accordance with various exemplary embodiments of the present disclosure, a hydroelectric turbine may include a stator comprising an electricity generating portion having coils and a rotor supported relative to the stator and configured to rotate relative to the stator about an axis of rotation. The turbine may also include a plurality of magnets arranged so as to generate electricity in the coils as the rotor rotates relative to the stator. The turbine may further include a plurality of first blade portions and second blade portions supported on the rotor. Each first blade portion may be radially outside of a circumference of the rotor and each second blade portion may be radially within the circumference of the rotor. Each blade portion may be angled in a tangential direction and angled downstream in an axial direction.

[010] In accordance with various additional exemplary embodiments of the present disclosure, an anchoring system for a hydroelectric turbine may include a turbine. The turbine may include a stator, a rotor supported relative to the stator and configured to rotate relative to the stator about an axis of rotation, and a plurality of blades supported on the rotor. The anchoring system may also include a tri-frame bottom portion. The bottom portion may include at least three anchor feet and at least three support beams, each support beam connecting an adjacent pair of the anchor feet. The anchoring system may further include a bridge. The bridge may include first and second ends and a support ring disposed between the first and second ends. Each of the first and second ends may be connected to the tri-frame bottom portion and the support ring may be configured to support the stator of the turbine thereon.

[011] Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present teachings. At least some of the objects and advantages of the present disclosure may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. [012] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure and claims, including equivalents. It should be understood that the present disclosure and claims, in their broadest sense, could be practiced without having one or more features of these exemplary aspects and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate some exemplary embodiments of the present disclosure and together with the description, serve to explain certain principles.

[014] FIG. 1 is a front perspective view of an exemplary embodiment of a hydroelectric turbine in accordance with the present disclosure;

[015] FIG. 2 is a side perspective view of the turbine of FIG. 1 ;

[016] FIG. 3 is an enlarged, partial perspective view of the turbine of FIG. 1 , with the cowling removed to show the fin block;

[017] FIG. 4 is a front view of the turbine of FIG. 1 ;

[018] FIG. 5 is a cross-sectional view of the turbine of FIG. 1 taken through line 5-5 of FIG. 4;

[019] FIG. 6 is an enlarged, partial view of the cross-section of FIG. 5; [020] FIG. 7 is a side perspective view of the turbine of FIG. 1 with an exemplary embodiment of an anchoring system in accordance with the present disclosure; [021] FIG. 8 is a front perspective view of the turbine and anchoring system of FIG. 7;

[022] FIG. 9 is a schematic side view of the turbine of FIG. 1 deployed from a barge in accordance with various exemplary embodiments of the present disclosure; [023] FIG. 1 0 is a graph illustrating the power output of a test turbine in accordance with the present disclosure;

[024] FIG. 1 1 is a graph illustrating the rotational speed of a test turbine in accordance with the present disclosure; and

[025] FIG. 1 2 is a graph illustrating the power output of a test turbine in accordance with the present disclosure as a function of river current. DESCRI PTION OF EXEMPLARY EMBODIMENTS

[026] In accordance with various exemplary embodiments of the present disclosure, blades (hydrofoils) of a hydroelectric turbine may be configured to optimize the collection of flow energy from a continuous, one-directional (i.e., unidirectional), freely flowing current like that found in rivers and some ocean currents. In contrast to blades that are designed to maximize total overall collection of flow energy from the ebb and flow of the two-directional flows found in, for example, tidal basins, the blades in accordance with the present disclosure can be configured to maximize total energy collection from a one-directional flow. [027] As used herein, the terms one-directional or uni-directional flow refer to currents through a hydroelectric turbine, which may have some differing directional components, but in which the overall movement during the majority of normal operation of the turbine is in a single direction. In other words, such flows are, for example upstream to downstream (or upriver to downriver), rather than in two generally opposite directions, as with the ebb and flow of a tidal current. [028] In accordance with various embodiments of the present disclosure, for example, a hydroelectric turbine may include design features that optimize, or at least improve, the ability of the turbine to: (1 ) collect a continuous, one-directional, freely flowing current in the body of water (e.g., a river or ocean) ; (2) minimize, or at least reduce, the possibility of impact with debris; (3) rid itself of debris that may impact the turbine, and/or (4) hold the turbine assembly in the current while minimizing, or at least reducing, the amount of materials for the turbine. Such features include the design and configuration of the blades (hydrofoils) of the turbine and an anchoring system for the turbine.

Turbine Blade Configurations

[029] FIGS. 1 -6 show an exemplary embodiment of a hydroelectric turbine 1 00 in accordance with the present disclosure. The turbine 1 00 includes a plurality of blades 1 02, wherein each of the blades 1 02 is swept backwards in both a tangential direction and an axial direction (e.g., in a direction of the flow F) to reduce the likelihood that debris in the flowing current F may impact the blades 1 02 (e.g., a direct impact with high force along the axial direction). In other words, as shown best perhaps in FIGS. 1 and 4, when viewing the turbine 1 00 from the front, each blade 1 02 can be angled from its base 1 03 to its tips 1 05 (free ends) in a direction opposite to the direction of rotation of the turbine 100 (e.g., counterclockwise rotation in the embodiment illustrated in FIGS. 1 -6). Moreover, such a configuration can enable the flow energy over the blade 1 02 to drive the debris along the surface of the blade and eventually off of the blade 1 02. In this manner, each blade 1 02 can be swept backwards away from the axial flow of the force energy, which may place the center of forces on the blade 1 02 closer to each side of a support or bearing system of a rotor 1 1 0 of the turbine 1 00 (see FIG. 5). It can also serve to better stabilize the forces to be contained by the bearing and enable less material to be used in manufacturing the support or bearing system.

[030] This swept back blade design may, therefore, help the flow energy in a one-directional current to guide debris through the turbine 1 00 with only a glancing blow to the surface of one or more of the blades 102, where the debris may

thereafter slide down the blade(s) 102 and proceed downstream with the current flow. In other words, the angling of the blades 102 in the tangential and axial directions allows the blades 102 to have a reduced profile {e.g., relative to a blade oriented with its lateral surface more perpendicular to the flow) within the current to minimize the chance of a head-on collision with debris, while also allowing the current to sweep the blades 102 of any debris that may come into contact with the blades 102.

[031] Those of ordinary skill in the art would understand that the turbine 100 illustrated in FIGS. 1 -6 is exemplary only and that the turbine 100 may have various arrangements, numbers, and/or configurations of blades 102, having various angles in the tangential and axial directions, which create various blade profiles, without departing from the scope of the present disclosure and claims.

[032] As illustrated in the cross-sectional views of FIGS. 5 and 6, each blade 102 can be coupled to a rotor 1 10 having magnets 1 14 embedded within or attached thereto. In various embodiments, for example, the rotor 1 10 can be rotatably supported relative to a stator 1 12, which supports one or more coils 1 16 for generating electricity. In this manner, fluid current forces on the blades 102 may cause rotation of the rotor 1 10 with respect to the stator 1 12. And, movement of the magnets 1 14 in the rotor 1 10 past the coils 1 16 in the stator 1 12 during the rotation may result in generation of electricity in the coils 1 14.

[033] Drag forces parallel to the direction of flow F and an axis of rotation A (see FIG. 1 ) of the rotor 1 10 may, however, act to axially displace the rotor 1 10 with respect to the stator 1 12. Accordingly, in various embodiments, the turbine 100 may also be configured to counteract axial displacement forces on the rotor 1 10. In various embodiments, for example, the turbine 100 may further include an arrangement of permanent magnets 1 1 6, 1 1 8 arranged, for example, in a partial Halbach array. In various additional embodiments, the permanent magnets 1 16, 1 1 8 can be replaced with other bearing mechanisms, such as, but not limited to, rollers (not shown) and water lubricated bearings made of wood or composite materials, such as, for example, a wood composite as commercially available from Lignum- Vitae North America of Powhatan Virginia. Such embodiments contemplate, for example, using a pattern of intermeshing teeth (e.g., between the rotor and Lignum- Vitae bearing) to contain the axial forces of the turbine.

[034] As shown in FIGS. 5 and 6, in various further embodiments, one or more rollers 1 20, 1 22 can be disposed on or in the stator 1 1 2 and/or the rotor 1 1 0 for rotatably supporting the rotor 1 1 0 on the stator 1 1 2 (i.e., to radially support the rotor 1 1 0 with respect to the stator 1 1 2). For example, each roller 1 20, 1 22 can be mounted at a first end of a respective arm 124, with an opposite second end of the respective arm 1 24 attached to the stator 1 1 2. The arms 1 09 may, for example, extend around a circumference of the rotor 1 1 0 and allow for the adjustment of the rotor 1 10's position with respect to the stator 1 1 2. In various embodiments, for example, an adjustment mechanism 1 26, such as, for example, a jack screw can interact with the arm 1 24 or a respective roller 1 20, 1 22 to center the rotor 1 1 0 with respect to the stator 1 12. In one exemplary embodiment, the turbine 1 00 may have twelve rollers 1 20 and twelve rollers 1 22 to support the rotor 1 1 0 on the stator 1 1 2.

[035] In accordance with various exemplary embodiments, the rotor 1 1 0 and stator 1 1 2 together form a support ring 1 50 for the blades 102, with the power generation and bearing systems integrated within the support ring 1 50. For example, the rotor 1 1 0 may include the blades 1 02 and form an inner portion of the support ring 1 50, while the stator 1 1 2 forms an outer portion of the support ring 1 50. In this manner, the ring 1 50 may provide intermediary support for the blades 102, thereby reducing the strength requirements for the blades 1 02. This in turn reduces the turbine 1 00's sensitivity to turbulence and allows the use of larger spans for the blades 1 02.

[036] As above, those of ordinary skill in the art would understand that the turbine 1 00 illustrated in FIGS. 1 -6 is exemplary only and that the rotor and stator configurations shown in the cross-sectional views of FIGS. 5 and 6, as well as the components used to support the rotor 1 10 relative to the stator 1 1 2, may have various other configurations and/or may employ various additional and/or alternative mechanisms without departing from the scope of the present disclosure and claims. In various embodiments, for example, the rollers 1 20, 122 can be replaced with other bearing mechanisms, such as, for example, magnetic bearing mechanisms (i.e., levitation magnets), as described, for example, in U.S. Publication No.

2012/021 1990, incorporated by reference herein. In various additional embodiments, the rollers 120, 1 22 can be replaced with water lubricated bearings made of wood or composite materials, such as, for example, a wood composite as commercially available from Lignum-Vitae North America of Powhatan Virginia. Such

embodiments contemplate, for example, using strips of Lignum-Vitae wood

composite arranged along an outer circumference of the core cylinder (e.g., 2x4 pieces of composite pushed into slots within the concrete of the stator) to serve as a radial bearing between the rotor and the stator.

[037] In accordance with various embodiments, each blade 1 02 can be hinged on its fulcrum over the rotor 1 10 so as to allow the blade 1 02 to fold inward. In other words, each blade 1 02 may fold toward the stator 1 1 2, such that a radially inwardly extending blade portion 1 01 a moves toward or almost parallel to a direction of the fluid flow F through the turbine 100. For example, a hinge feature (not shown) can be provided at a location 128 on the radially inwardly extending blade portion 101 a. Alternatively or additionally, a second hinge feature (not shown) can be provided at location 130 on a radially outwardly extending blade portion 101 b. In various embodiments, for example, a hinge line (not shown) for each blade portion 101 a, 101 b may extend tangentially, or follow a compound curve, that defines a connection line {e.g., at locations 128, 130) between a central blade portion 107 that attaches to the rotor 1 10 and the respective blade portions 101 a, 101 b.

[038] In accordance with various embodiments of the present disclosure, in order to avoid damage to the blades 102, the above hinge feature(s) can be configured to be actuated whenever debris strikes one of the blades 102 with a force exceeding a predetermined value. Alternatively or additionally, the portion 101 a of each blade 102 that is directed radially inward of the stator 1 12 can be configured to deflect in accordance with the hinge feature to allow large debris to pass through the inner region of the stator 1 12, for example, to allow debris to pass through the turbine 100 that would otherwise be unable to pass through the already open center defined by the inner edges of the blades 102 of the turbine 100. In this manner, whenever a too-large-to-pass piece of debris strikes the turbine 100, the force of the impact and/or the axial force resulting from the increased drag on the inner portion 101 a of the blades (i.e., due to the obstruction of fluid flow through the open center) will fold back the inner portions 101 a of the blades 102 to allow the turbine 100 to rid itself of the large debris. As above, in various embodiments, only the radially inner portions 101 a of the blades 102 of the turbine 100 are provided with the hinge feature, while the radially outer portions 101 b of the blades 102 are not configured to be displaced toward or away from the stator 1 12 by impact with debris. While, in various additional embodiments, both the inner portions 1 01 a and outer portions 1 01 b are provided with hinge features.

[039] In accordance with various embodiments, the hinge feature(s) can be equipped with a stop (not shown) to prevent the blade 1 02 from folding outward (e.g., away from the stator 1 1 2). In other words, the stop allows the blade 1 02 to only fold in an inner direction (e.g., toward the stator 1 1 2). In accordance with various additional embodiments, the radially inner portion 101 a and the radially outer portion 1 01 b of each blade 1 02 can be connected at a pivot point such that folding of the inner portion 1 01 a toward the stator 1 1 2 causes an opposite motion of the outer portion 1 01 b away from the stator 1 1 2. In this manner, since the sweep of the flow energy collected by the outer portion 1 01 b of the blade 1 02 is greater than the sweep of the flow energy collected by the inner portion 1 01 a of the blade 1 02, the flow forces acting on the outer portion 1 01 b of the blade 1 02 will immediately right the blade 1 02 (i.e., return it to its normal state) after each impact event that is significantly large enough to cause the inward folding of the blade portion 1 01 a.

Alternatively or additionally, the turbine may include springs (not shown) to minimize the impact of shocks associated with such impact events.

[040] In various exemplary embodiments, as shown in FIG. 5, the turbine 1 00 may further include cowlings 1 32, 1 34 respectively at a front of the rotor-stator arrangement and at a rear of the rotor-stator arrangement. The cowlings 1 32, 1 34 may be removable with respect to the rotor-stator arrangement and thus can be assembled separately. For example, each blade 1 02 may be coupled to the rotor 1 1 0 via a front support piece 1 1 1 and a rear support piece 1 1 3, with the central portion 1 07 of each blade 102 being disposed between the front and rear support pieces 1 1 1 , 1 13 in the axial direction. The front cowling 1 32 may be attached to the front support piece 1 1 1 or any other portion of the rotor 1 1 0, and the rear cowling 1 24 can be attached to a downstream portion of the stator 1 1 2 on an opposite side of the turbine 1 00 from the front cowling 1 32. In various embodiments, the cowlings 1 32, 1 34 can have a smooth shape, such as, for example, an aerodynamic shape, which may help to reduce the impact of fluid current forces on the turbine 1 00. In other words, the cowlings 1 32, 1 24 may streamline the flow around the turbine 1 00 and help to protect various components of the turbine 1 00, for example, from impact with debris.

[041 ] In various additional exemplary embodiments, as shown best perhaps in the enlarged view of FIG. 3 in which the front cowling 1 32 has been removed to expose a fin block 1 36, the blades 1 02 may be coupled to the rotor 1 1 0 via bolts 140. In this manner, the rotor blades 1 02 may be easily accessed and removed from the rotor 1 10 for replacement {e.g., in the event that a blade 1 02 is damaged, for example, by debris) or for changing/replacement of the blades 1 02 with different blades 1 02 (e.g., for different river currents). River flows, for example, are often variable and may change drastically throughout the year, being strong (i.e., having high speeds) during spring run-offs and weak (i.e. having low speeds) at the end of the summer months or during times of drought. Accordingly, it may be desirable to change the size of the blades 1 02 of the turbine 100 based on the flow conditions of the river, or other body of water, in which the turbine 1 00 is deployed. For example, larger blades 1 02, with a larger surface area, may be used in low flow conditions, in comparison with the blades 1 02 used in high or normal flow conditions. Turbine Testing

[042] To confirm the expected performance of a hydroelectric turbine, such as, for example, the turbine 100 illustrated in FIGS. 1 -6, a series of tests were conducted in both a test tank and in the field.

Tow Tank Testing

[043] To obtain clean baseline performance data on the turbine, preliminary testing was conducted in a tow tank. The tank was 15 m wide by 6 m deep by 545 m long (i.e., 50 ft X 20 ft X1800 ft), with a carriage that bridged across the tank. Four 450 hp motors were then used to drive the carriage, while pushing the submerged turbine through the undisturbed water of the tank.

[044] The testing sequence, for example, involved the following steps: (1 ) positioning the carriage at the far end of the tank; (2) lowering the turbine into the water; (3) starting instrumentation recording; (4) ramping carriage speed up to a predetermined value until it neared end of travel; (5) decelerating the carriage to a stop; and (6) reversing steps (1 ) to (3) in preparation for the next test sequence.

[045] The electrical power generated by the turbine was dissipated in an adjustable resistive load bank. By selecting different resistors to include in the electrical load, the voltage, current, electrical power output, and rotational speed of the generator could be varied. Accordingly, the test matrix included variations in the load bank settings.

[046] A suite of performance parameters was measured using a high-frequency datalogger. The measured power and rotational speeds for the test turbine are illustrated in FIGS. 10 and 1 1 , respectively. River Testing

[047] The river testing was conducted on the Tanana River in Alaska. A barge platform that was anchored in the river was used to conduct the testing. An exemplary barge 300, including a lift mechanism 350 that was used to deploy the test turbine 100, is shown in FIG. 9.

[048] The turbine 100 and instrumentation were nearly identical to that tested at the tow tank, with the exception of some external capacitors being changed to improve the electrical power generation of the turbine 100. For the testing, the turbine 100 was lowered (i.e., by the lift mechanism 350) to approximately 2 meters (6.5 ft) below the water level of the river.

[049] The Tanana River is glacier fed, so by September when the tests were conducted, the flow rates had dropped to below 1 .8 m/s (3.5 knots), and the water level continued to drop during the 2 week test period.

[050] As before, a large amount of performance data was collected to characterize the power generation of the test turbine 100 as a function of river flow. As above, a capacitance adjustment was made that improved power output. The corresponding corrected power output curve for the test turbine 100 is illustrated in FIG. 12. The solid line represents the measured tow tank data that was adjusted based on the performance increase observed from the river testing. Since the river flow was below 3.5 knots, the adjusted power was extrapolated to the higher speeds using a cubic function of current speed.

[051] As above and discussed further below, since the turbines in accordance with the present disclosure are scalable to other sizes, while employing the same general design concept, the power output at other sizes was also estimated. For example, if the turbine 100 was doubled in sweep diameter, the power output would be expected to increase by a factor of 4.

Turbine Anchoring Systems

[052] As illustrated in FIGS. 7 and 8, various additional exemplary embodiments of the present disclosure contemplate an anchoring system 200 for holding a hydroelectric turbine, such as, for example, the turbine 100 in a stationary position within a fluid flow {e.g., within a river). For example, the anchoring system 200 may include a tri-frame 202 with three anchoring feet 204 configured to be disposed on or in a ground surface, such as, for example, a river bed or ocean floor. The tri-frame 202 may also have one or more support beams 206 connecting each anchoring foot 204 to an adjacent anchoring foot 204. In various embodiments, the anchoring system 200 may also include a bridge 210 that extends vertically from the tri-frame 202 to a ring 208 that supports the stator 1 12 of the turbine 100. The bridge 210 may, for example, connect to one of the tri-frame support beams 206 at each end thereof.

[053] In various additional exemplary embodiments, the anchoring system 200 can be angled forward, as best shown in FIG. 7, where the bridge 210 slants toward an upstream direction of the fluid flow F. This forward sweeping design allows for a lighter anchoring structure 200 that uses less material. As a result, the anchoring system 200 can be lifted in and out of its collection point, e.g., on the river bottom or ocean bottom, with less difficulty, for example, by using a handle 209 and/or handle 219. Moreover, the forward slant design prevents the anchoring system 200 from tumbling under the force of the current F, while the use of cleats 212 (or another structure configured to be embed in the ground surface) at the base of the tri-frame 202 can prevent the anchoring system 200 from slipping along the ground surface {e.g., the river bottom or the ocean floor) due to flow energy.

[054] Those of ordinary skill in the art would understand that the anchoring system 200 illustrated and described with respect to FIGS. 7 and 8 is exemplary only, and that anchoring systems in accordance with the present disclosure may have various structural configurations and utilize various mechanisms to support the hydroelectric turbines of the present disclosure within a fluid flow without departing from the present disclosure and claims. Furthermore, anchoring systems in accordance with the present disclosure can be manufactured and/or assembled using any known technique and/or method, using various materials. In various embodiments, for example, the anchoring system 200 can be made as an integral part. While in various additional embodiments, the anchoring system 200 can be made of separate pieces that are subsequently joined together. Furthermore, in various exemplary embodiments, the anchoring system can be formed of a

composite material.

[055] Those of ordinary skill in the art would further understand that the turbines of the present disclosure can be held within fluid flows (e.g., within a river current) using various additional known methods and/or techniques, including, for example, a barge platform 300 as illustrated in FIG. 9.

[056] Although features disclosed herein are directed to applications such as in rivers with a one-directional current flow, it should be readily apparent that the disclosed embodiments or aspects thereof may find application in other aquatic environments, such as, but not limited to, the ocean, as well as in the collection of energy from fluids other than water. For example, it may be desirable to provide a hydroelectric turbine that optimizes the collection of energy from a one-directional flow and for which it is relatively easy to stably reposition the device depending on the direction of flow of a current.

[057] This description and the accompanying drawings that illustrate exemplary embodiments should not be taken as limiting. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the scope of this description and the claims, including equivalents. In some instances, well-known structures and techniques have not been shown or described in detail so as not to obscure the disclosure. Furthermore, elements and their associated features that are described in detail with reference to one embodiment may, whenever practical, be included in other embodiments in which they are not specifically shown or described. For example, if an element is described in detail with reference to one embodiment and is not described with reference to a second embodiment, the element may nevertheless be included in the second embodiment.

[058] It is noted that, as used herein, the singular forms "a," "an," and "the," and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term "include" and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

[059] Further, this description's terminology is not intended to limit the

disclosure. For example, spatially relative terms— such as "beneath", "below", "lower", "above", "upper", "forward", "front", "behind," and the like— may be used to describe one element's or feature's relationship to another element or feature as illustrated in the orientation of the figures. These spatially relative terms are intended to encompass different positions and orientations of a device in use or operation in addition to the position and orientation shown in the figures. For example, if a device in the figures is inverted, elements described as "below" or "beneath" other elements or features would then be "above" or "over" the other elements or features. Thus, the exemplary term "below" can encompass both positions and orientations of above and below. A device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[060] Further modifications and alternative embodiments will be apparent to those of ordinary skill in the art in view of the disclosure herein. For example, the devices may include additional components that were omitted from the diagrams and description for clarity of operation. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the present disclosure. It is to be understood that the various embodiments shown and described herein are to be taken as exemplary. Elements and materials, and arrangements of those elements and materials, may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the present teachings may be utilized

independently, all as would be apparent to one skilled in the art after having the benefit of the description herein. Changes may be made in the elements described herein without departing from the scope of the present disclosure.

[061] It is to be understood that the particular examples and embodiments set forth herein are non-limiting, and modifications to structure, dimensions, materials, and methodologies may be made without departing from the scope of the present disclosure. Other embodiments in accordance with the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with being entitled to their full breadth of scope, including equivalents.

Claims

WHAT IS CLAIMED IS:

1 . A hydroelectric turbine comprising:

a stator comprising an electricity generating portion having coils;

a rotor supported relative to the stator and configured to rotate relative to the stator about an axis of rotation;

a plurality of magnets arranged so as to generate electricity in the coils as the rotor rotates relative to the stator; and

a plurality of first blade portions and second blade portions supported on the rotor, each first blade portion being radially outside of a circumference of the rotor and each second blade portion being radially within the circumference of the rotor, wherein each blade portion is angled in a tangential direction and angled downstream in an axial direction.

2. The hydroelectric turbine of claim 1 , wherein each blade is supported on the rotor by a hinge mechanism configured to allow the second blade portion to fold inward.

3. The hydroelectric turbine of claim 1 , wherein each blade is supported with a pivot or fulcrum between the first and second blade portions, the first blade portion being configured to move in the axial direction opposite to the second blade portion.

4. The hydroelectric turbine of claim 1 , further comprising at least one cowling coupled to the rotor at an upstream portion thereof.

5. The hydroelectric turbine of claim 1 , further comprising at least one cowling coupled to the stator at a downstream portion thereof.

6. The hydroelectric turbine of claim 1 , wherein the rotor is disposed radially inward of the stator.

7. The hydroelectric turbine of claim 1 , wherein each first blade portion is integrally formed with a corresponding second blade portion.

8. The hydroelectric turbine of claim 1 , wherein each first blade portion is formed separate from and subsequently attached to a corresponding second blade portion.

9. The hydroelectric turbine of claim 1 , wherein the first and second blade portions are each bolted to the rotor.

10. An anchoring system for a hydroelectric turbine, the turbine comprising a stator, a rotor supported relative to the stator and configured to rotate relative to the stator about an axis of rotation, and a plurality of blades supported on the rotor, the anchoring system comprising:

a tri-frame bottom portion comprising at least three anchor feet and at least three support beams, each support beam connecting an adjacent pair of the anchor feet; and

a bridge comprising first and second ends and a support ring disposed between the first and second ends, each of the first and second ends being connected to the tri-frame bottom portion, the support ring being configured to support the stator of the turbine thereon.

1 1 . The anchoring system of claim 10, wherein the bridge is slanted in an axial direction such that the support ring is disposed further upstream than a portion of the bridge that is connected to the tri-frame bottom portion.

12. The anchoring system of claim 10, further comprising cleats configured to engage with a river bed or ocean floor.

13. The anchoring system of claim 10, wherein the first and second ends extend from respective support beams.

14. The anchoring system of claim 10, wherein the tri-frame bottom portion and the bridge are formed of a composite material.