Hydrodynamic generators and systems

Abstract

This disclosure relates to hydrodynamic generators including their structural design, deployment methods, anchoring systems, drive systems, and control systems. The systems can be scaled from hand-carried to large stationary devices capable of generating up to 20 kW or more in a 3 knot current. In the stationary system, the device can be anchored to the water bed by an anchoring device supported by four adjustable legs. These legs can eliminate the need for large mooring lines and provide the device with a small footprint that is not dangerous to marine animals or plants. Individual components such as rotors, generators, and other mechanical components can be installed modularly for ease of removal and inspection without the need to interrupt the entire system.

Description

[Technical field]

[0001] The present disclosure relates generally to a system for generating power from hydrodynamic forces, and in particular, for generating electricity from tides and river currents. [Background technology]

[0002] Systems designed to extract energy from the natural flows of oceans and rivers have been available for many years, but issues with efficiency, cost, deployment, reliability, and environmental impact have prevented them from becoming a reliable source of electricity generation. The need to address these issues has long been recognized, and improvements in the field are needed to increase the use of these energy sources as part of the global energy portfolio. Summary of the Invention

[0003] Different hydro-electric generator designs and methods of their deployment and use are described herein.

[0004] According to an embodiment, a housing for a hydrodynamic system includes a duct having an inner surface and an outer surface defining a central flow passage, an annular compartment defined by the inner surface and the outer surface, the annular compartment housing at least one mechanical component coupled to a generator, and at least one ballast tank located in the annular compartment, the duct is substantially circular in cross section, the central flow passage has a first diameter, the duct further includes a first opening of a second diameter and a second opening of a third diameter, both of the second diameter and the third diameter being greater than the first diameter.

[0005] According to another embodiment, a hydrodynamic system includes a duct, a plurality of rotors held within the duct, a strut securing one of the plurality of rotors to the duct, a differential in mechanical communication with at least some of the plurality of rotors, and a generator. Each rotor includes a plurality of blades and a hub connecting the blades of the rotor to a rotor shaft. The strut defines a channel for receiving a belt or a drive shaft, the belt or drive shaft being in mechanical communication with the rotor shaft. The differential is constructed and arranged to receive different rotational speed inputs from at least some of the plurality of rotors and to drive an output shaft at a single rotational speed. The generator is coupled to the output shaft and configured to generate electrical power based on rotation of the output shaft.

[0006] According to another embodiment, an anchor structure for a hydrodynamic generator includes a platform having an upper surface and a lower surface, a semicircular cradle coupled to the upper surface of the platform, and a plurality of telescopic legs coupled to an edge of the platform. The semicircular cradle is configured to support a cylindrical duct having one or more rotors disposed within the duct. At least one of the telescopic legs includes a cable configured to pass through a corresponding telescopic leg and connect to an anchor secured to the floor of the body of water.

[0007] According to another embodiment, a hydrodynamic electric system includes one or more rotors held in a duct configured to be deployed within a body of water, a generator, a transfer cable coupled to the generator, and a battery charger. Each rotor includes a plurality of blades and a hub connecting the blades of the rotor to a rotor shaft. The generator is configured to output electrical power based on rotation of the rotor shaft of each of the one or more rotors. The transfer cable is configured to convey the output electrical power out of the duct to a land-based control station. The battery charger is configured to charge one or more batteries based on the output electrical power.

[0008] According to another embodiment, a method for deploying a hydrodynamic device comprises anchoring one or more cables to a floor of a body of water; anchoring the hydrodynamic device to an anchor structure having a plurality of telescoping legs; passing at least one of the one or more cables through at least one of the telescoping legs on the anchor structure; reducing the buoyancy of the hydrodynamic device, thus submerging both the hydrodynamic device and the anchor structure in the body of water; guiding the anchor structure to the floor via one or more cables passing through at least one of the telescoping legs; and anchoring the anchor structure to the floor. [Brief description of the drawings]

[0009] [Figure 1] 1 illustrates an example of a fluid dynamics system having a duct resting on an anchor structure, according to some embodiments of the present disclosure.

[0010] [Figure 2A] 2 illustrates a duct diagram of the fluid dynamics system of FIG. 1 according to some embodiments of the present disclosure. [Figure 2B] 2 illustrates a duct diagram of the fluid dynamics system of FIG. 1 according to some embodiments of the present disclosure. [Figure 2C] 2 illustrates a duct diagram of the fluid dynamics system of FIG. 1 according to some embodiments of the present disclosure.

[0011] [Diagram 3] 2 illustrates an anchor structure used to support the hydrodynamic system from FIG. 1 according to some embodiments of the present disclosure.

[0012] [Figure 4A] 1 illustrates a cross-sectional view of a fluid dynamics system according to some embodiments of the present disclosure.

[0013] [Figure 4B] 1 illustrates a cross-sectional view of another rotor design for a fluid dynamic system according to some embodiments of the present disclosure.

[0014] [Diagram 5] 1 illustrates a connection between a hydrodynamic system deployed on a water bed and a land-based control station according to some embodiments of the present disclosure.

[0015] [Figure 6] 1 illustrates an example rotor blade design for a fluid dynamic system according to some embodiments of the present disclosure.

[0016] [Figure 7A] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7B] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7C] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7D] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7E] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7F] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7G] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7H] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7I] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7J] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7K] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7L] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure. [Figure 7M] 1A-1D show various views of a portable fluid dynamics system according to some embodiments of the present disclosure.

[0017] [Figure 8] FIG. 1 is a flow diagram of a method for deploying an underwater hydrodynamic system and anchor structure according to some embodiments of the present disclosure.

[0018] [Figure 9] FIG. 13 is a flow diagram of another method for deploying a hydrodynamic system and anchor structure underwater according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] [overview] The present disclosure relates to hydrodynamic generators, including their structural design, deployment methods, anchoring systems, drive systems, and control systems. The systems can be scaled from hand-carried to large stationary devices that can generate up to 20 kW or more in a 3 knot current. In stationary systems, the device can be anchored to the ocean or river bottom by a cradle supported by four adjustable legs. These legs can eliminate the need for large mooring lines and provide the device with a small footprint that is not dangerous to endangered species such as right whales. Individual components such as rotors, generators, and transmissions can be installed modularly for ease of removal and inspection without the need to interrupt the entire system. In portable systems, the device can be small enough to be carried on a person's back or hoisted between two people and placed in a river or other location with a flowing water. Portable systems can have the same overall rotor and generator design as larger stationary systems, but scaled down.

[0020] The system can employ multiple rotors to extract maximum energy at relatively low speeds and provide redundancy if one of the rotors fails or needs to be serviced. The rotors are exposed to high flow rates by rotating around a small central hub that transmits mechanical energy via shafts or belts located on struts that connect the rotors to the housing. With no motor or generator housing in the flow stream, more flow can be utilized. The system can be bidirectional to utilize tidal changes without changing position. The rotor blades can auto-feather depending on the direction of the flow. Multiple rotors can be mechanically linked via single or multiple transmissions. Alternatively, the rotors can drive independent generators and the electrical output of each can be combined.

[0021] The housing has a cone-shaped inner surface that is narrow in the middle and widens towards each opening. This reduction in cross-sectional area helps accelerate the flow over the rotor. The widening of the area at the outlet also contributes to the acceleration of the flow. The outer surface can match the contour of the inner surface or can be different, for example cylindrical or ovoid. Compartments are formed in the space between the inner and outer walls. These compartments can house electrical and mechanical components, as well as buoyancy chambers that can be filled and emptied to change the total buoyancy and attitude of the device. The ballast system allows the device to be pulled on the water surface, providing the operator with an easy means to sink the device to its intended depth. Additionally, the ballast system can be used with portable devices to maintain a fixed depth below the water surface or above the sea or river bottom. The outer surface of the device can include fins, which can be extendable, to stabilize the device in the currents to which it is exposed. The buoyancy chambers and / or fins can also be used to help adjust the yaw of the device to maximize the flow of water through the device.

[0022] The housing of the device may include a coating or outer skin that provides, for example, damage protection, corrosion protection, electrical insulation, sound insulation, and resistance to biological growth. The outer skin may be of consistent or varying colors and patterns, selected for camouflage purposes or to scare away marine animals. Alternatively or additionally, the device may release chlorine gas from multiple outlets along the outer edge of the duct opening. The chlorine gas travels along the inner surface of the duct, helping to clean any biofouling of the surface and recombining with the water. The chlorine gas may be extracted from the saltwater via an electrolysis process, described in more detail herein.

[0023] The methods of deployment and extraction can vary depending on the size of the system and the end use. Smaller versions of the device can be deployed in rivers by one or two people simply placing the device in the water flow and anchoring one, two or more anchor points as described above. Medium-sized versions can be deployed in rivers without direct attachment to the riverbed by suspending the device in the flow using cables. Larger versions can be deployed to the seabed or riverbed. In systems with stationary anchor devices, one, two, three, four or more cables can be anchored to the seabed floor using, for example, T-anchors or screw anchors. The fixed cables are threaded through the legs of the support system and the device is brought to the seabed by sliding the cables through the legs. In this manner, each leg can be positioned directly on or near an anchor point. The cables can be removed or retained in the support system to avoid any possibility of interfering with marine life. In some cases, the device can be steered into position by driving one or more rotors and using them as low speed propellers to provide thrust.

[0024] Control systems include systems for monitoring, diagnostics, and operation. Devices may be autonomous in nature or may receive commands from a remote operator, which may be wired or wireless. For example, ballast tanks may be controlled automatically or remotely to provide optimal angle of device for maximum flow-through. Rotors, transmissions, and generators may provide real-time data on power output, efficiency, and health. Remote cameras, microphones, level, pressure sensors, flow meters, and temperature gauges may provide additional information on nearby animals, vibration noise, mechanical movements, and debris build-up levels on filtration screens.

[0025] The systems described herein can be deployed for temporary use (e.g., part of a day) or for extended periods of use (e.g., years). Maintenance is minimized as a result of the housed components, bio-resistant coatings, and modular design. Once the system is deployed, it should not need to be retrieved until the end of its useful life, e.g., 20 years. The use of filtering screens prevents large animals, plants, and debris from entering the system, and the slow moving rotor allows for the safe passage of smaller marine animals. The device can operate unobtrusively below the vessel's depth, allowing for deployment in any location that provides available flow. For example, the device can be moored 20 ft (6.1 m), 30 ft (9.1 m), 40 ft (12.2 m), or 50 ft (15.2 m) below the water's surface.

[0026] The system described herein can provide on-demand local power generation for a variety of applications. Batteries installed locally, either in the annular compartment of the device itself or at another nearby location connected via a cable, can be used to store electrical energy not currently being used. Power can then be drawn at any time from the batteries or directly from a generator in the device. A control system can be used to determine whether power is drawn from the batteries, the generator, or both. Exemplary applications for the system described herein include marine charging stations at docks or any other location where moving water is present. [Duct and anchor structure design]

[0027] 1 shows an example of a hydrodynamic system 100 including a large duct 102 resting on an anchor structure 104 in an underwater environment, according to some embodiments. The hydrodynamic system 100 may be deployed in water for long periods of time (e.g., years) to generate electrical energy from the underwater water currents that spin one or more rotors in the duct 102. Due to the life of the hydrodynamic system 100 and the presence of the anchor structure 104, the duct 102 may be made very large (e.g., about 50 feet (15.2 m) long, about 30 feet (9.1 m) diameter at its widest flared end) to generate large amounts of electrical energy based on the flow of a large volume of fluid over the rotors.

[0028] According to some embodiments, the duct 102 includes a grid 106 over each of the openings to prevent larger debris from entering the duct 102. The grid 106 can have a convex shape as shown to passively cause debris to slide away from the openings of the duct 102 after contacting the grid 106. In some embodiments, the grid 106 includes a repeating pattern of 1 square inch (6.5 square centimeters) or more, such as a repeating square pattern, a repeating diamond pattern, or a repeating triangular pattern. The grid 106 can be made from stainless steel, although any other sufficiently rigid material with good anti-biofouling properties can also be used.

[0029] While the rotor within the duct 102 rotates based on the speed of the water flow, the grate 106 can be used to prevent larger objects, such as cigarette butts, marine mammals, large fish, debris, and divers, from traveling through the duct 102. This helps prevent potential damage to the rotor as well as potential damage to the inside of the duct 102. In some embodiments, the grate 106 is removable if or when it needs to be cleaned. In some instances, the bidirectional flow of water through the duct 102 helps maintain the grate 106 on regular maintenance cycles. In other cases, the device can be flipped 180 degrees longitudinally so that the flow of water passes through the device in the opposite direction.

[0030] According to some embodiments, the anchor structure 104 includes a number of legs 108 that contact the bottom or floor of the underwater environment to stabilize the anchor structure 104. Each of the legs 108 may be a telescoping leg having an adjustable length to compensate for an uneven underwater surface. The anchor structure 104 may also include an area for holding a generator 110, such as an AC generator, that is coupled to a mechanical rotor in the duct 102 via one or more linkages, as described in more detail herein. Power generated from the generator 110 may be conveyed to an onshore control station via one or more cables that extend from the generator 110 to the onshore control station, for example, along the bottom of the water.

[0031] According to some embodiments, the anchor structure 104 is submerged in water and anchored to the bottom at a predetermined location. The duct 102 is then submerged in water and guided over the anchor structure 104 until it settles on top of the anchor structure 104. In some embodiments, the weight of the duct 102 alone is sufficient to keep it settled on top of the anchor structure 104. In some other embodiments, the duct 102 is mechanically secured to the anchor structure 104 after it is aligned above and on top of the anchor structure 104. Further details regarding the design and operation of each of the components of the fluid dynamics system 100 are described herein.

[0032] 2A shows a three-dimensional representation of a duct 102, according to some embodiments. The duct 102 includes a central passage 202 that connects a first flared end 204 to a second flared end 206. Each of the first flared end 204 and the second flared end 206 terminates in an opening having a diameter larger than the diameter of the central passage 202. In some embodiments, the first flared end 204 is identical to the second flared end 206. Thus, the openings at the end of each of the first flared end 204 and the second flared end 206 may have the same diameter. The central passage 202 may include substantially flat walls between each of the first flared end 204 and the second flared end 206. In some other embodiments, the central passage 202 includes curved or angled walls such that a continuous curved outer surface is formed between each of the first flared end 204 and the second flared end 206. The curvature may be inward or outward.

[0033] 2B shows a front view of the duct 102, according to some embodiments. The duct 102 may be formed via multiple panels 208a-c joined together, with the seams filled, for example, with an injectable epoxy. Each of the panels 208a-c may be substantially identical to one another. Although three panels are shown, any number of panels may be used to form the duct 102. The duct 102 may have an outer diameter d1 between about 12 inches (30.48 centimeters) and about 24 inches (60.96 centimeters), between about 20 inches (50.80 centimeters) and about 40 inches (101.60 centimeters), between about 30 inches (76.20 centimeters) and about 50 inches (127.00 centimeters), between about 20 inches (50.80 centimeters) and about 80 inches (203.20 centimeters), or between about 80 inches (203.20 centimeters) and about 90 inches (228.60 centimeters), such as about 84 inches (213.36 centimeters), and an inner diameter d2 (e.g., at the midpoint of the central passage 202) between about 55 inches (139.7 centimeters) and about 65 inches (165.1 centimeters), such as about 59 inches (149.86 centimeters). The outer diameter d1 may be consistent along its length or may vary, for example, the outer diameter may be the same along its length, may be larger in the middle portion, or may be larger at either or both ends.

[0034] 2C shows a cross-sectional view of a duct 102 having a parabolically curved inner surface and a flat outer surface between openings at opposite ends of the duct 102. Thus, the diameter of the duct 102 increases continuously outward from the midpoint of the duct (having diameter d2) to each end of the duct (having diameter d1). In some examples, the duct 102 has a total length L between about 30 inches (76.2 centimeters) and about 60 inches (152.4 centimeters), between about 40 inches (101.6 centimeters) and about 80 inches (203.2 centimeters), or between about 105 inches (266.7 centimeters) and about 135 inches (342.9 centimeters), such as about 120 inches (304.8 centimeters).

[0035] The duct 102 may be formed using interlocking panels, such as any number of curved segments that mechanically link together, or may be one integrally machined piece. The duct 102 and all of its associated surfaces may be formed from composite materials, machined steel, or stainless steel. The inner diameter of the central passage 202 is defined by the inner surface of the duct 102, while the outer surface of the duct 102 provides its overall shape. In some embodiments, the outer surface of the central passage 202 remains flat and extends between the first flared end 204 and the second flared end 206, while the inner surface of the central passage 202 curves inwardly between the first flared end 204 and the second flared end 206, such that the inner diameter of the central passage 202 has a minimum distance at the midpoint between the first flared end 204 and the second flared end 206.

[0036] According to some embodiments, there is an annular compartment between the inner and outer surfaces of the duct 102. In some embodiments, the annular compartment extends at least around the central flowpath 202. In some embodiments, the annular compartment includes some of the mechanical components used to transfer mechanical energy to the generator. In some embodiments, the annular compartment includes one or more ballast tanks that can be filled with air or water to affect the total buoyancy of the duct 102. Further details regarding the mechanical connections within the duct 102 and its annular compartment are provided with reference to Figures 4A and 4B.

[0037] The flared ends of the ducts 102 may be used to enhance the water flow through the central passage 202. Horizontal axis turbines located in the central passage 202 are generally preferred over vertical access turbines because they are easier to auto-actuate and have higher efficiency and higher speed operation. In addition, horizontal axis turbines have smaller torque fluctuations. According to some embodiments, one role of a converging flare (e.g., a flared end acting as an inlet) is to increase the mass flow or velocity of the water through the central passage 202, thereby increasing the extracted power potential. This flow directly affects the rotor speed. According to some embodiments, one role of a diverging flare (e.g., a flared end acting as an outlet) is to spread the water as it exits the central passage 202, which may further create a suction effect that draws water out of the central passage 202 at a higher velocity than a flat edged cylinder.

[0038] FIG. 3 shows an isometric three-dimensional representation of the anchor structure 104 with the duct 102 removed, according to an embodiment. The anchor structure 104 includes various components arranged to support and secure the duct 102. According to some embodiments, the core of the anchor structure 104 includes a platform 302 having an upper surface and a lower surface, and a cradle 304 coupled to the upper surface of the platform 302. The cradle 304 may have a semicircular shape sized to fit snugly around the central flow passage 202 of the duct 102. Although only one cradle 304 is shown, there may be multiple cradle structures arranged in a row to support the duct 102. In some embodiments, the cradle 304 has a different shape to fit the contour of the outer shape of any duct that rests thereon. The cradle 304 and / or the platform 302 may be constructed from any fiberglass reinforced plastic (FRP) and / or stainless steel.

[0039] In some embodiments, the platform 302 includes one or more apertures 306 extending between the upper and lower surfaces of the platform 302. The apertures 306 may be cut into a particular shape or design. According to some embodiments, the presence of the apertures 306 reduces the overall weight of the anchor structure 104, allowing the structure to sink more easily when deployed to the bottom of an underwater environment.

[0040] A number of guide posts 308 may also be connected to the top surface of the platform 302. The guide posts 308 may additionally be used to support the duct 102 at a given location above the platform 302. In some embodiments, the guide posts 308 extend above the height of the duct 102 and are angled outwardly to provide a wedge shape between which the duct 102 can fit.

[0041] According to some embodiments, the anchor structure 104 includes a number of legs 310 coupled to the platform 302. Each of the legs 310 may be coupled to a corner of the platform 302 or along a different side of the platform 302. Four legs 310 are shown in FIG. 3, however, any number of legs 310 may be used. According to some embodiments, the legs 310 are adjustable height telescoping legs for resting on uneven water beds. The legs 310 may be slightly flared outward to create a trapezoidal stance for the anchor structure 104. This shape allows the anchor structure 104 to effectively resist lateral forces coming from any direction, thus allowing the supported duct 102 to maintain its precise position despite tidal changes, debris impacts, high waves, etc.

[0042] Each of the legs 310 has a first end that extends above the platform 302 and a second end that extends below the platform 302. According to some embodiments, compression rods (not shown) may be used to connect between adjacent legs 310 to provide additional structural support. According to some embodiments, a distal portion of the second end of each leg 310 has a foot pad 312. The foot pad 312 may be flexible to provide better traction against the water bed.

[0043] According to some embodiments, the foot pads 312 are designed to fit over anchors 314 that are secured to the water bed. For each corresponding leg 310, a separate anchor 314 may be secured within the water bed. According to some embodiments, a cable is fastened to a given anchor and routed through a hollow in a corresponding one of the legs 310. When the cables, each connected to a respective anchor, are routed through each of the legs 310, the entire anchor structure 104 can be submerged in water and guided by the cable through each of the legs 310 until it is aligned over each corresponding anchor 314.

[0044] A hydrographic survey of the installation site may first be performed to position the anchor structures 104 in the exact location and orientation for optimal power generation. Each anchor location may be determined and installed prior to deployment of the anchor structures 104. In one example, the survey provides sonar imagery (x, y, z sounding) of the on-site waterway to allow pre-adjusting the length for each of the legs 310. The survey may also provide sufficient detail of the bottom texture and composition to allow planning for the type of anchor 314 required for each leg 310. After the survey is completed, the specific anchors 314 of each leg may be secured to the water bed and the cables may then be extended to the surface. Each of the pre-drilled, embedded or fastened anchor cables may then be threaded through their respective legs 310 of the anchor structures 104. When the anchor structures 104 are submerged in water, these cables guide each leg 310 to its own exact pre-defined location on the corresponding anchor 314. According to some embodiments, each leg 310 with its respective foot pad 312 covers its corresponding anchor 314 when the anchor structure 104 is submerged on the bottom. In some embodiments, a series of pulleys and cams are disposed within each leg 310 to allow the cables to tension, firmly anchoring the anchor structure 104 to the water bed. Further details regarding the deployment of the anchor structures 104 and ducts 102 are provided herein.

[0045] According to some embodiments, the anchor 314 is an injection embedment anchor. An injection embedment anchor is a type of anchor that is effective in sand, mud, silt or gravel bottoms. The anchor is typically injected into the waterbed through a pre-positioned cylindrical structure using a fire hose from a container elevated above the sea surface. The fire hose provides sufficient pressure inside the cylinder to temporarily relieve the seabed compression at the nozzle and push the anchor mechanism deep into the waterbed. When the cylinder is removed, the displaced sediment fills the cavity it left and firmly fixes the embedded anchor. The holding capacity of an injection embedment anchor can be amplified by either increasing the anchor cone diameter (area), the installation depth, compacting the sediment under overload, or using a cement slurry.

[0046] According to some embodiments, anchor 314 is a plate anchor. In one example, the circular plate anchor includes a large circular plate that is embedded in the water bed in a vertical orientation and then provides retention when moved to a horizontal orientation. In this horizontal position, the plate anchor resists upward removal from the water bed.

[0047] According to some embodiments, the anchor structure 104 includes a secondary platform 316 (extending above the platform 302) coupled between first ends of adjacent ones of the legs 310. The secondary platform 316 may be arranged parallel to the platform 302. An additional secondary platform may be provided on the opposite side of the anchor structure 104. The secondary platform 316 may include an area 318 configured to support a pod including a generator. In this manner, the pod can be placed in the area 318 and easily removed from the area 318 to perform possible maintenance on the generator or to replace it with another generator.

[0048] According to some embodiments, hollow piles 320 are coupled to the underside of the platform 302. The hollow piles 320 extend towards the water bed and can provide a conduit for running power cables and / or any other electrical cables. Any of the cables can carry the current generated from the generator or provide power to any sensors located around the duct 102 or on the generator. According to some embodiments, the cables can be routed along the water bed (or under the water bed) through the hollow piles 320 and carried to a control station on the ground. In some embodiments, the hollow piles 320 can be driven, anticipated or fastened into the water bed and act as a central guide and / or primary anchor for the anchor structure 104. In some embodiments, one or more compression rods (not shown) can be used to connect between the hollow piles 320 and any of the legs 310 to provide additional structural support.

[0049] FIG. 4A shows an example of a cross-section through the duct 102 to show various mechanical components and connections of the hydrodynamic system according to some embodiments. The various mechanical components may not be drawn to scale and may be located in different relative positions with respect to each other. As explained above, the hydrodynamic system includes a series of rotors 401 disposed in the central flow path of the duct 102. In general overview, water pressure caused by tides and water currents is pumped through the duct 102 and rotates the rotor blades 402 on each rotor shaft 404. These rotational speeds may be relatively low, however, due to the strong force of the water currents, the torque remains high. Spur gears 406a may be connected to the end of each rotor shaft 404 and mesh with the teeth of a tensioned timing belt 408 that may be oriented perpendicular to the rotor shafts 404. In some embodiments, the timing belt 408 is replaced by a drive shaft. Each timing belt 408 runs through the inside of a corresponding watertight strut diffuser 410 and transfers the rotational torque of the rotor shaft to one or more primary shafts 412. These primary shafts 412 may be located in separate sealed cavities 414 attached to the outside of the duct 102 and extending lengthwise along the sides of the duct 102. In some other embodiments, an annular section between the inner and outer surfaces of the duct 102 houses the primary shafts 412 and other mechanical components coupled to the primary shafts 412. In some embodiments, the majority of the mechanical couplings and other mechanical components are provided within the sealed cavity 414 (or annular section), leaving a large space for water to flow through the duct 102. According to some embodiments, the strut diffusers 410 provide structural support for the rotor 401, however, may be designed to promote positive efficiency as water flows around them. A differential gearbox 416 (referred to herein as a differential) may be provided to allow each primary shaft 412 to rotate at different speeds. Due to the different locations of the rotor 401 inside the duct 102, it is possible that the rotor 401 may rotate at different speeds.Torque may be transferred from the primary shaft 412 to one of two generators 418 via one or more output shafts 420. According to some embodiments, the generator 418 is angled relative to the primary shaft 412, and the output shaft 420 is designed to allow for misalignment and vibration damping. In some embodiments, the generator 418 is located within the sealed cavity 414 or within an annular compartment around the duct 102. In some other embodiments, the generator 418 is located separately from both the duct 102 and the sealed cavity 414, and can be brought to the surface separately from the rest of the system for maintenance or replacement. Although two generators 418 are shown, any number of generators may be provided on a single hydrodynamic system, including only a single generator 418.

[0050] According to some embodiments, when tidal currents change (e.g., in speed and / or direction), the blade angles of the rotor blades 402 need to change and allow for optimal efficiency. A governor 422 located inside the rotor housing 424 is configured to sense the blade angles and can be controlled from a land-based station. For example, if one of the rotors 401 needs maintenance, the corresponding governor 422 can change the blade pitch of the rotor blades 402, and a centrifugal clutch 426 coupled to the corresponding timing belt 408 can be configured to sense low rpm of the rotor 401 and engage a brake between the corresponding timing belt 408 and either the output shaft 420 and / or the primary shaft 412. Any of the primary shafts 412 can be stopped using this method, while the other primary shafts 412 continue to rotate based on the rotation of the other rotor. If the generator 418 needs to be removed for maintenance, all of the primary shafts 412 can be stopped via one or more centrifugal clutches 426 to allow disengagement of the generator.

[0051] According to some embodiments, the rotor blades 402 of a given rotor 401 are connected to a central hub 428 that further connects the rotor blades 402 to a corresponding rotor shaft 404 in a rotor housing 424. A rotor bearing 430 is disposed around the hub 428, allowing the rotor blades 402 to rotate freely. According to some embodiments, each rotor 401 includes three blades 402. The blades may have the general shape of a Kaplan blade, as described in more detail herein. Each rotor blade 402 may be formed from a composite material due to their strength and low-maintenance nature. According to some embodiments, as shown in FIG. 4A, three rotors 401 are disposed within the duct 102, however, in other configurations, any number of rotors 401 may be used, such as only two rotor blades as described with reference to FIG. 4B. According to some embodiments, the rotor blades 402 of a given rotor 401 are canted in rotational position relative to the rotor blades of the other rotors, and are strategically positioned to allow for maximizing flow efficiency and power generation. To maximize performance or to stop the blades 402 from rotating, the blade angle of a given set of rotor blades 402 can be changed at any time using the corresponding governor 422. According to some embodiments, the blade angle of a given rotor blade 402 can be passively changed between two positions based on the direction of the water flow. Two separate pins or protrusions on either side of the rotor blade can act as stopping points to prevent the rotor blade from rotating any further. For example, the rotor blade can be pressed against one of the pins when the water flows in one direction, and when the water changes direction, the blade can rotate until it rests on the other pin. This allows the rotor to passively rotate to an efficient angle of attack when the water flow changes direction. For example, the blade angle of attack on a first side can be 10 degrees, and when the water flow changes direction, the blade can rotate on the hub to provide an angle of attack of 10 degrees on the opposite side.

[0052] According to some embodiments, the strut diffuser 410 may also house any other mechanical linkages and / or bearings. The strut diffuser 410 may be fused to the inner surface of the duct 102. According to some embodiments, the strut diffuser 410 is made from steel and / or composite materials and has a shape that increases the aerodynamic flow of the surrounding fluid. In some embodiments, a cooling system is included within a given strut diffuser 410 to reduce heat generated by friction from the timing belt 408 and / or spur gear 406a.

[0053] According to some embodiments, rotor shaft 404 is a hollow drive shaft that allows passage of power connectors for electric blade pitch actuators configured to change the pitch and angle of rotor blades 402. In some embodiments, the size of rotor shaft 404 is minimized while maintaining performance specifications with a safety factor of at least 1.5 to reduce overall weight and improve the selection of supporting components such as seals, bearings, couplings, etc.

[0054] According to some embodiments, the centrifugal clutch 426 is configured to use centrifugal force to disengage the output shaft 420 or the primary shaft 412 from the centrifugal clutch 426 in response to the rotational speed of the corresponding rotor 401 dropping below a threshold value. In some embodiments, the centrifugal clutch 426 includes its own spur gear 406b for engaging the timing belt 408.

[0055] According to some embodiments, a differential 416 is used to combine mechanical power from two or more drive shafts that rotate at different speeds. The differential 416 includes a gear train with three shafts, where the rotational speed of one shaft is the average of the other speeds, or a fixed multiple of that average. In one example, a spur gear differential has two equally sized spur gears with a space between them, one on each half shaft. At the center of the differential 416 is a rotating carrier on the same axis as the two shafts. Torque from a prime mover or transmission, such as from one of the primary shafts 412, rotates this carrier. Mounted on this carrier are one or more pairs of pinions, generally longer than their diameter and typically smaller than the spur gears on the individual half shafts. Each pinion pair rotates freely on a pin supported by the carrier. Additionally, the pinion pairs are axially displaced so that they mesh between the two spur gears for only a portion of their length and rotate in opposite directions. The remaining length of a given pinion meshes with the nearest spur gear on its shaft. Each pinion thus connects its spur gear to other pinions and to other spur gears, so that when the corresponding primary shaft 412 rotates the carrier, the relationship of the individual axles to the gears is the same as that found in a bevel gear differential. Any number of differentials 416 may be provided and protected within the sealed cavity 414 (or within an annular compartment around the duct 102).

[0056] According to some embodiments, each of the generators 418 is placed in its own pallet (e.g., a sealed box) that can be removed from the rest of the system. The pallet may include a handle or lifting gear to provide a lifting point. Guiding and / or locking mechanisms can be used to ensure that the pallet is lowered in the correct location on the system and that the coupling of each generator 418 is aligned with the corresponding output shaft 420. According to some embodiments, a coupling mechanism 432 is provided along with a lip seal 434 to create a watertight area around the output shaft 420 when coupling between the generators 418 and within the sealed cavity 414.

[0057] According to some embodiments, one or more power cables 436 and control / sensor cables 438 are provided to supply power from the generator 418 and to provide power to various sensors and / or controllers present on the hydrodynamic system. Each of the power cables 436 and control / sensor cables 438 may run parallel to one another between the hydrodynamic system and the onshore control station. According to some embodiments, the control / sensor cable 438 provides power to one or more sensors, such as, for example, a sensor disposed on the hub 428 configured to monitor the blade angle for the rotor blades 402, a sensor disposed on the inner surface of the duct 102 configured to monitor the flow rate and direction of water through the duct 102, and a sensor disposed on the strut 410 configured to monitor the integrity of the connection between the rotor shaft 404 and the timing belt 408, a sensor coupled to the generator 418 configured to monitor the performance of the generator 418, a sensor disposed within the sealed cavity 414 configured to monitor the performance of any of the mechanical components within the sealed cavity 414, such as the primary shaft 412, the differential 416, and the centrifugal clutch 426, or one or more pressure and / or temperature sensors disposed throughout various portions of the fluid dynamic system. Additionally, one or more controllers may be provided to control the operation of the governor 422 and / or the generator 418, which receive power via the control / sensor cable 438.

[0058] According to some embodiments, a second sealed cavity 440 may be secured to another area on the exterior surface of the duct 102. The second sealed cavity 440 may include one or more ballast tanks 442 that may be individually filled with water or air to modify the buoyancy of the overall hydrodynamic system. In some examples, both the sealed cavity 414 and the second sealed cavity 440 are part of the same annular compartment that extends around the outside of the duct 102.

[0059] According to some embodiments, instead of using a separate control / sensor cable 438 to provide power to sensors and / or controllers on the hydrodynamic system, the system includes one or more batteries that can be charged from the power output from the generator 418. The charge from these batteries can be used to power sensors and / or controllers on the hydrodynamic system. In some embodiments, the battery is an embedded battery that is molded or otherwise shaped to fit within the duct 102. The battery can be contained within either the sealed cavity 414, the second sealed cavity 440, or an annular area around the outside of the flow path through the duct 102. The batteries used on the hydrodynamic system can be Absorbent Glass Mat (AGM) batteries or Lithium-ion batteries, to name a few. On-demand power can be drawn locally from the batteries for various applications.

[0060] FIG. 4B shows an example of another rotor design in the duct 102 including a first rotor 401a and a second rotor 401b. According to some embodiments, the rotors 401a and 401b are designed to rotate in opposite directions. For example, the rotor 401a may include blades shaped such that the rotor 401a rotates clockwise, while the rotor 401b includes blades shaped such that the rotor 401b rotates counterclockwise, or vice versa. The use of two counter-rotating rotors provides enhanced stability of the device while also improving efficiency. The two rotors may be symmetrically positioned on either side of the midpoint of the duct 102. The duct 102 is shown in this example as having a parabolically curved inner surface that flares outward from the midpoint of the duct 102 along its length.

[0061] According to some embodiments, rotors 401a and 401b may face in opposite directions (due to their counter-rotating design) and be coupled to opposite ends of a common shaft 404. Each rotor also includes its own strut diffuser 410 coupled to the common shaft 404. The mechanical design and generator coupling for each of rotors 401a and 401b may be substantially similar to rotor 401 described above with reference to FIG. 4A. Dimensions may vary between specific applications, however, in some examples, the distance between the hubs of each of rotors 401a and 401b is between 10 inches (25.4 centimeters) and 30 inches (76.2 centimeters), or between 25 inches (63.5 centimeters) and 35 inches (88.9 centimeters), such as about 30.9 inches (78.4 centimeters). In some examples, the distance between the strut diffusers 410 is between about 6 inches (15.24 centimeters) and 2 feet (60.96 centimeters), such as about 1.5 feet (45.72 centimeters). Each of the strut diffusers 410 may also have a diameter between about 1 inch (2.54 centimeters) and 3 inches (7.62 centimeters), such as less than 1 inch, less than 2 inches (5.08 centimeters), or less than 3 inches. According to some embodiments, the distance d between the tip of the rotor blades of either rotor 401a or 401b and the inner surface of the duct 102 is between about 0.5 inches (1.27 centimeters) and 5 inches (12.7 centimeters), such as about 2 inches (5.08 centimeters), less than 2 inches (5.08 centimeters), or less than 1 inch (2.54 centimeters).

[0062] 5 illustrates an example of a hydrodynamic electrical system with a hydrodynamic system 100 that generates electrical energy based on the movement of water through the system, and an onshore control station 502 that receives the electrical energy generated by the hydrodynamic system 100. According to some embodiments, the hydrodynamic system 100 is anchored to a water bed 503 below a water surface 504. One or more cables 506 are routed from the hydrodynamic system 100, through hollow pilings 320, along the water bed 503, and received at the control station 502. As explained above, the cables 506 may include both power cables to provide electrical power generated from one or more generators on the hydrodynamic system 100, and / or control / sensor cables to provide power and control signals to various sensors and / or controllers on the hydrodynamic system 100.

[0063] Each of the one or more generators present on the fluid dynamics system 100 may be configured to generate 120 volts alternating current (AC) that is provided to the control station 502 via a power cable in one or more cables 506. As part of the generating units on the fluid dynamics system 100, one or more voltage regulators may be provided to maintain a constant voltage output.

[0064] According to some embodiments, the control station 502 provides a user interface for the operation of the hydrodynamic system 100. According to some embodiments, the control station 502 also functions to receive, store, and distribute electrical power coming from the hydrodynamic system 100 via one or more underwater cables 506. The control station may also collect information from various sensors monitoring environmental, mechanical, and electrical data, such as ocean currents, revolutions per minute of each rotor, and electrical output, via one or more underwater cables 506. In some embodiments, an operator can monitor and operate the hydrodynamic system 100 from one or more terminals directly on-site (e.g., at the control station 502) or remotely through a computing device and a wireless connection, such as cellular, WiFi, 4G, 5G, or Bluetooth.

[0065] According to some embodiments, the control station 502 includes any number of power converters 508 to convert electrical energy between AC and DC power. For example, some power converters 508 may be used to convert AC power received from the fluid dynamics system 100 to DC power for storage in one or more storage devices (e.g., batteries). In another example, some power converters 508 may be used to convert DC power stored in one or more storage devices back to AC power before distribution to the power grid or directly to customers. Such power converters 508 that convert from DC power to AC power may be referred to as inverters. According to some embodiments, one or more battery chargers 510 may be designed to receive DC power from the power converters 508 and use the received DC power to charge one or more storage devices. The charging protocol depends on the type and size of the storage device being charged.

[0066] According to some embodiments, the control station 502 includes one or more computing devices with a touch screen display or other type of user interface that allows an operator to monitor the health of one or more components of the fluid dynamics system 100. The interface may include an emergency or manual brake function to slow or stop the rotation of any of the rotors in the fluid dynamics system 100. In some embodiments, the operator may be alerted if any alarms are activated, such as generator overheating, brake failure, electrical failure, rotor failure, etc. Diagnostic details collected from various sensors or controllers may be provided via the touch screen display or other type of user interface. Such sensors / controllers may include acoustic sensors, vibration sensors, brake status sensors for monitoring the status of the rotor brakes, battery monitors for providing diagnostic information about the storage devices such as charge rate, charge current, and battery voltage, battery controllers for protecting the storage devices from overcharging and controlling the charge rate, and acoustic Doppler flow velocity profiler sensors for predicting maximum and minimum potential flow velocity values, to name a few.

[0067] FIG. 6 illustrates example geometric details for the rotors 401, and more specifically, the shape of the rotor blades 402, according to some embodiments. Each rotor 401 may be designed with three identical rotor blades 402 extending radially from a hub 428. In some examples, the rotor blades 402 may have a chord-to-diameter ratio (c / D) at the root of between about 0.225 and about 0.275, and at the tip of between about 0.050 and about 0.100. In another example, the rotor blades 402 have a blade length-to-diameter ratio (b / D) from root to tip of between about 0.2 and about 0.6. In another example, the diameter (d hubThe ratio between the diameter (d) of the hub 428 and the rotor diameter (D) is between 0.075 and 0.100. In some embodiments, the hub 428 has a diameter (d) that is less than 10% of the diameter (D) of the rotor 401, such as about 7% of the diameter (D) of the rotor 401. hub In some examples, d hub is between about 3 inches (7.62 centimeters) and about 5 inches (12.7 centimeters), such as about 3.9 inches (9.9 centimeters).

[0068] As previously described, the ducts of the hydrodynamic system can have several possible sizes. Larger ducts (e.g., on the order of tens of feet in diameter) can be used for more permanent hydrodynamic systems and can be anchored in place (e.g., using anchor structures 104) to provide power for periods of weeks or even years. However, smaller hydrodynamic systems (e.g., having ducts with diameters between about 1-3 feet (30.48-91.44 centimeters)) can provide portable (e.g., capable of being carried by one or two people) generators for on-demand power applications and / or temporary power generation. Such smaller hydrodynamic systems can be more quickly deployed in shallower waters (such as rivers, streams, or lakes) and more quickly removed, making them useful for conversion operations or any application requiring quick, temporary power close to a water source.

[0069] 7A-7M show various views of a hydrodynamic system 700 using a smaller duct design (e.g., less than 2 feet in diameter), according to some embodiments. The electrokinetic mechanisms (e.g., rotors, mechanical linkages, etc.) within the hydrodynamic system 700 may be similar to those described above for the larger hydrodynamic system 100, but with scaled-down dimensions. However, other aspects of the design of the hydrodynamic system 700 may differ to take advantage of its smaller size and portability. Some of these other aspects include an anchoring system that provides both stability for the hydrodynamic system 700 and the adaptability to allow the hydrodynamic system 700 to flip 180 degrees in water if desired.

[0070] FIG. 7A shows a side view of a hydrodynamic system 700 according to some embodiments. Like the larger version, the hydrodynamic system 700 includes a duct 702 that allows water to pass through the duct 702 to rotate one or more rotors disposed within the duct 702. The duct 702 includes a flow passage connected between two openings at both ends. The diameter of each opening of the duct 702 is larger than the diameter of the midpoint of the flow passage connecting the two openings. In some embodiments, the duct 702 has a shape similar to the duct 102 described with reference to FIGS. 2A-2C. However, in some other embodiments, the duct 702 has a shape similar to that shown in FIG. 7A with a continuous curved (e.g., parabolically curved) surface between both openings at both ends of the flow passage. In still other embodiments, the duct 702 has a curved inner surface that forms a flow passage between the openings, but has a flat outer surface between the openings. The duct 702 may be formed from any lightweight and sufficiently rigid material, such as composite material, mild steel, or stainless steel.

[0071] According to some embodiments, multiple pallets 704, each holding a generator, are positioned along a particular portion of the duct 702. The multiple pallets 704 may be arranged in a row to provide any number of pallets (including only one). Each pallet may be easily inserted and removed to provide quick and easy access to the generators within each pallet. The generators may function in the same manner as described above for the hydrodynamic system 100. Any of the multiple pallets 704 may include a handle or some other lifting point to facilitate insertion and removal of each pallet 704. In some embodiments, any of the pallets 704 holds one or more rechargeable batteries that can be charged from electricity generated by the hydrodynamic system 700.

[0072] According to some embodiments, a platform 706 is provided along the length of the duct 702 between each opening. The platform 706 extends along a portion of the length and extends outwardly from the duct 702. In some embodiments, the duct 702 includes two identical platforms 706, one on each side of the duct 702. The platforms 706 may include an aerodynamic design that provides stabilization of the duct 702 when placed in water. Additionally, the platforms 706 may provide gripping points to aid in carrying the duct 702. In some embodiments, the platform 706 includes fins 707 that extend along a portion of the platform 706. The fins 707 may be provided for increased stabilization of the duct 702 when placed in water. In some embodiments, the fins 707 are retractable and can retract into the platform 706 during storage and transportation and extend outwardly to provide enhanced stabilization after the duct 702 is placed in water.

[0073] According to some embodiments, the duct 702 is held below the water surface using anchors 708, such as helical anchors, that are drilled into the water bottom. Cables 710 wrap around or are otherwise attached to the anchors 708 and extend to two or more attachment points 712 on the duct 702. The attachment points 712 may be located along the same horizontal plane along the length of the duct 702. In some embodiments, each attachment point 712 is located near a corresponding end of the duct 702, giving the cables 710 a wider angle from the anchors 708 for increased stability.

[0074] According to some embodiments, each of the two openings of the duct 702 is covered with a grid 714 to protect the rotor inside the duct 702. The grid 714 can have a convex shape as shown to passively cause debris to slide away from the opening of the duct 702 after contacting the grid 714. In some embodiments, the grid 714 includes a repeating pattern, such as a repeating square pattern, a repeating diamond pattern, or a repeating triangular pattern. The grid 714 can be made from stainless steel, although any other sufficiently rigid material with good anti-biofouling properties can also be used. In some embodiments, the grid 714 is flexible enough to be inverted into a concave shape that bends inward toward the center of the duct 702.

[0075] FIG. 7B shows a different view of the fluid dynamics system 700 when looking through the flow path of the duct 702, according to some embodiments. According to some embodiments, fins 707 extend on either side of the duct 702 to help stabilize the duct 702 below the water surface. Two anchors 708 may be used on either side of the duct 702 to maintain the position of the duct 702 below the water surface. According to some embodiments, the duct 702 may be placed in an underwater environment having a depth D1 between about 2 feet (60.96 centimeters) and about 3 feet (91.44 centimeters) (e.g., 2.35 feet (71.62 centimeters)). The duct 702 may be anchored to the bottom of the water using anchors 708 spaced apart a distance W1 between about 4 feet (121.92 centimeters) and about 5 feet (152.4 centimeters) (e.g., 4.81 feet (146.6 centimeters)). FIG. 7C shows another view of the hydrodynamic system 700 showing both anchors 708 connecting the duct 702 to a location below the water surface.

[0076] 7D shows a cross-sectional view of a duct 702 according to some embodiments. Similar to the duct 102 described above, the duct 702 can have an annular section 715 that wraps around the flow path and holds various mechanical components or other elements described herein. For example, the annular section 715 can include one or more ballast tanks 716 that can be individually filled with air or water to affect the buoyancy of the duct 702. In some embodiments, the annular section 715 also includes chambers 718 that remain filled with air. Depending on which chambers or ballast tanks are filled with air or water, the buoyancy of the duct 702 can be altered so that the duct 702 floats just below the water surface. In some embodiments, any of the ballast tanks 716 can be filled with water to tilt the duct 702 forward or backward, thus flipping the entire duct 702 180 degrees underwater, and thus reversing the orientation of the duct 702 along the direction of the water flow. In some embodiments, any of the ballast tanks 716 can be filled with water to adjust the location of the duct 702 to any position in the water column below the water surface. The ballast tanks 716 can also be used to control the angle of the duct 702 relative to the water flow. For example, the ballast tanks 716 can adjust the angle of the duct 702 ±10 degrees from horizontal. The ballast tanks 716 can also be adjusted to compensate for changes in water density due to changes in salinity or temperature, for example. In this manner, the buoyancy on the anchor or tether can be maintained constant.

[0077] The annular compartment 715 also includes one or more hollow recesses 720 for placing the pallets 704 in corresponding recesses 720, according to some embodiments. As described above, the pallets 704 may house a generator or a battery for storing energy generated by the hydrodynamic system 700. In the flow path of the duct 702, one or more rotors 722 are suspended via one or more struts 724 connected to the inner surface of the duct 702. The operation and design of the rotors 722 may be similar to that of the rotor 401 from the hydrodynamic system 100. Although three rotors are shown, the hydrodynamic system 700 may include only two rotors mounted and designed to rotate in opposite directions, as described above with reference to FIG. 4B.

[0078] According to some embodiments, the hydrodynamic system 700 can generate local power at any destination using a moving body of water or tidal currents. This locally generated power can then be directly transmitted to any number of other underwater or surface vessels via underwater or other electrical connectors. Additionally, power can be provided to any land-based location via one or more power cables.

[0079] 7E illustrates the size of the hydrodynamic system 700 according to some embodiments. In some examples, the hydrodynamic system 700 has a length (L1) between about 2 feet (60.96 centimeters) and about 3 feet (e.g., 2.55 feet (77.72 centimeters)) and an overall diameter (D2) between about 1.5 feet (45.72 centimeters) and about 2 feet (e.g., 1.85 feet (56.38 centimeters)). According to some embodiments, the hydrodynamic system 700 is sized to fit comfortably on an adult's back (e.g., having a height of about 6 feet (182.88 centimeters)) for ease of transportation in hard to reach places.

[0080] 7F shows another view of the fluid dynamics system 700 with the lattice 714 inverted to create a concave shape, according to some embodiments. The lattice 714 can be inverted to make transportation of the fluid dynamics system 700 easier.

[0081] 7G shows another view of the fluid dynamics system 700 with the rim cover 726 removed from one end of the duct 702, according to some embodiments. The rim cover 726 can be screwed onto a given end of the duct 702 with an identical rim cover on the opposite end. Either or both rim covers can be removable to expose an annular recess 728 that can be used to hold a cable or any other item. In some embodiments, the rim cover 726 is removed by unscrewing the various screws that hold the rim cover to the end of the duct 702. In some other embodiments, the rim cover 726 snaps into place over the end of the duct 702 and can pop out when a sufficient amount of force is applied, exposing the annular recess 728.

[0082] FIG. 7H shows a view of the inside of the annular recess 728 with one or more cables 730 packed in, according to an embodiment. In some examples, the one or more cables 730 include cables connected to anchors 732 that can be pulled out and driven into the water bottom. FIG. 71 shows how an anchor cable 734 can be paid out from within the annular recess 728. According to some embodiments, the anchor cable 734 has an anchor 732 connected to one end, so that it can be quickly pulled out of the annular recess 728 and deployed into the water bottom while still attached to the anchor cable 734. According to some embodiments, the other end of the anchor cable 734 can be attached to any anchor point 712 on the duct 702. The one or more cables 730 can also include a power cable that can be paid out of the annular recess 728 and used to provide power (generated by any of the one or more generators on the hydrodynamic system 700) to any land-based device.

[0083] FIG. 7J shows a closer view of one edge of the opening of the hydrodynamic system 700, according to an embodiment. At either or both ends of the duct 702, a hose 736 can extend around at least a portion of the perimeter of the opening. The hose can be used to distribute a biocide that can be generated on-board. The hose 736 can have a wall thickness of about 3 / 8 inch (0.952 centimeters) and a tube diameter of, for example, ¼ inch (0.635 centimeters) to 2 inches (5.08 centimeters). The hose 736 can include an opening 738 or can be porous. The opening or hole can extend around its entire perimeter or only one or more portions. The hose 736 can be constructed of a metal or polymer and can be painted, anodized, or coated with a material such as SerpentScale EPDM granules. Preferred materials for the hose include those that are chlorine and hypochlorite resistant, such as halogenated polymers including, for example, PTFE, PFA, CPVC, and E-CTFE.

[0084] The hose 736 can provide fluid communication from a biocide source to the interior surface of the duct, rotor, strut, or any part of the device susceptible to biofouling. The biocide source can be a reservoir of biocide or can be a biocide generator. In some embodiments, the biocide is generated from seawater, for example, a chlorine compound such as chlorine gas, hypochlorite ions, or hypochlorous ions, each of which can be electrolyzed from seawater and are effective marine biocides. The electrolyzed seawater can be generated using electricity from an on-board generator, or can be generated using stored power such as from a battery or capacitor. In a specific example, using titanium electrodes, sodium hypochlorite is generated directly from the seawater. Simultaneously, hydrogen gas can be electrolyzed and stored or discharged. Upon production of the chlorine compounds in the seawater, the compounds can be immediately dispensed or stored and released at a later time.

[0085] As used herein, a compound provides a "biocidal effect" if biological growth, such as algae, slime, and barnacles, is prevented or inhibited as compared to treatment with ambient seawater. The chlorine compound is provided at a concentration high enough to provide a biocidal effect on one or more portions of the device when flowed into the water passing through the duct. For example, the concentration of the chlorine compound at production can be greater than 100 mg / L, greater than 1000 mg / L, or greater than 10000 mg / L. The concentration of the chlorine compound after being dispensed into the seawater and measured one foot downstream of the hose 736 can be greater than 0.1 mg / L, greater than 0.5 mg / L, greater than 1 mg / L, or greater than 2 mg / L. To improve contact time with various surfaces of the device, the chlorine compound can be dispensed when the water flow through the duct is not at a maximum. For example, the chlorine compound can be dispensed when the flow rate through the duct is less than 1 m / s, less than 0.5 m / s, or less than 0.1 m / s. In tidal applications, these slow flows may be seen before and after a slack water flow. Because tides and currents can be accurately predicted, chlorine compounds can be generated and dispersed on a pre-planned schedule to take advantage of the low flow conditions.

[0086] Biofouling can also occur in fresh water, but in fresh water applications where salt water is not available, a salt or salt water reservoir can be included on board to provide a raw material for chlorine compound production. By using salt water as the chloride source, chlorine compounds can be electrolyzed using methods similar to those used in sea water. Power can be provided by a hydrodynamic system and distribution can occur in the same manner as in sea water. In embodiments where the device is intermittently inverted to change direction and release trapped material, the release of chlorine compounds can be coordinated with the position change so that most or all of the device is exposed to a level of chlorine compounds that provides a biocidal effect.

[0087] According to some embodiments, the cable 710 may be connected to a single connection point (rather than two connection points as shown in FIG. 7A) that can move along a track along the length, or a portion of the length, of the duct 702. A single movable connection point allows the duct 702 to flip or rotate underwater while still being anchored to the bottom of the water. The duct 702 may include at least two such connection points on opposite sides of the duct 702. FIG. 7K shows a slidable connection point arranged on a side of the duct 702, according to an embodiment. The carriage 740 is designed to slide laterally over a bracket 742, such as a T-shaped bracket or any other suitable shape. According to some embodiments, the carriage 740 includes a loop 744 to which the cable 710 can be attached. In some embodiments, the carriage 740 can slide freely over the bracket 742 based on the force of pulling the cable passing through the carriage 740. In some embodiments, a screw mechanism 746 is provided to move the carriage 740 over the bracket 742. The screw mechanism 746 may be operated using power drawn from any of the generators on the hydrodynamic system 700 .

[0088] 7L shows another view of a carriage 740 coupled to a bracket 742, according to an embodiment. The carriage 740 may include a body 748 shaped to clamp around the bracket 742, allowing the body 748 to slide laterally over the bracket 742. Coupled to the body 748 may be two or more tethers 750 to which loops 744 may be rotatably attached. In some examples, the loops 744 are free to rotate about an axis passing through the center of each of the tethers 750.

[0089] FIG. 7M shows another view of the hydrodynamic system 700 using a single connection point on its underside to a single anchor 708, according to an embodiment. According to an embodiment, a cable is fastened to the end of a loop 744 that is part of the carriage 740. As described above with reference to FIGS. 7K and 7L, the carriage 740 can be translated along the bottom of the duct 702. By changing the location of the cable connection point, the duct 702 can become unstable and flip 180 degrees in the water. For example, the carriage 740 can be translated along the surface of the duct 702 to a point where the center of the lateral plane shifts to the other side of the carriage 740, making the duct most stable in the 180 degree direction from its original position. This can be very useful to help clear any obstructions that may be present for the grid 714. According to some embodiments, the anchor 708 is a helical anchor, such as the helical anchors provided by Eco-Mooring (Milford, NH). A similar process can be performed using two anchor lines and two anchor points, where both anchor points are moved longitudinally until the device is flipped 180 degrees from its original position. According to some embodiments, the length L of the duct 702 is between about 0.7 m and about 1.3 m, such as about 1 m. According to some embodiments, the overall width W of the duct 702 is between about 0.4 m and about 0.7 m, such as about 0.57 m.

[0090] In some embodiments, the hydrodynamic system 700 can be anchored to any surface instead of the bottom of the water. For example, one or more anchors can be secured to the underside of floating ice in polar regions. This can allow the hydrodynamic system 700 to be maintained at a constant depth above the water's surface regardless of how deep the water may be. The hydrodynamic system 700 maintains its depth and its relative location to the ice. Retention lines can be drilled into the ice from below, or cables can pass completely through the ice and be maintained, for example, using a T- or mushroom-shaped anchor mechanism on the top surface of the ice.

[0091] In some circumstances, the hydrodynamic system 700 may be dropped into a body of water from the air (such as from a helicopter or other aircraft). Thus, the duct 702 and rotor machine are designed to withstand the impact of the duct 702 hitting the water surface after being dropped from the air. According to some embodiments, the anchor cable may be wrapped around the outer surface of the duct 702. The anchor cable may then be naturally deployed from the duct 702 after being placed in the water. According to some embodiments, the weight of the anchor continues the unspooling motion until the anchor is embedded in the water bed. Typically, the deployment embodiment involves a single anchor line and a single anchor. If the depth of the area to be dropped is known, the length of the anchor line can be selected precisely. In other cases, an anchor line is provided that is long enough to embed the anchor in the bed, and the actual position of the device in the water column can be adjusted using one or more of fins or ballast tanks.

[0092] 8 shows a flowchart 800 describing a method for deploying a hydrodynamic system in a body of water, according to some embodiments. The method involves anchoring the system to the floor of an underwater environment, where both the anchor structure and the hydrodynamic system are first attached together and then the two are both submerged in the water. The acts, functions, or actions described in each block of flowchart 800 may be performed in a different order than shown, and any two or more blocks may be performed simultaneously in some circumstances.

[0093] According to some embodiments, anchors are secured to the water bed at block 802. Any type of anchor may be used, such as T-anchors, screw anchors, plate anchors, or injection embedment anchors. The anchors may be arranged in a specific pattern to match the position of the legs from the anchor structure that are aligned over the anchor.

[0094] According to some embodiments, the cables are secured to the anchors at block 804. The cables may be fastened or welded to each anchor before the anchors are driven into the water bed. The cables may be long enough to extend from the water bed above the water surface so that the other ends of the cables can be used with an anchor structure, such as anchor structure 104.

[0095] According to some embodiments, the fluid dynamic device is secured to an anchor structure at block 806. For example, a fluid dynamic device, such as fluid dynamic device 100, may include a large duct to allow water to pass through the duct and spin a rotor within the duct. The cylindrical shape of the duct may rest on a cradle that is coupled to an anchor structure, such as anchor structure 104. According to some embodiments, after the fluid dynamic device is secured to the anchor structure, the two are submerged below the surface of the water.

[0096] According to some embodiments, at block 808, the cables attached to the anchors are threaded through the legs of the anchor structure. The legs of the anchor structure include a hollow portion to allow the cable of a given anchor to be threaded through one of the legs of the anchor structure. In some instances, the cable passes through the distal end of a given leg and emerges at the opposite end of the leg.

[0097] According to some embodiments, the buoyancy of the hydrodynamic device is reduced at block 810. Buoyancy can be reduced through the use of one or more ballast tanks on the hydrodynamic device, such as a portion of a duct. Certain ballast tanks can be partially or completely filled with water to alter the weight of the hydrodynamic device and affect the rate at which the hydrodynamic device sinks in water, or to cause the hydrodynamic device to remain in a given position below the water surface.

[0098] According to some embodiments, at block 812, the anchor structure (with attached hydrodynamic device) is guided over the anchor in the water. The anchor structure may be guided via a cable that extends through one or more of the legs of the anchor structure. The cable may be held taut while the anchor structure slowly sinks into the water. According to some embodiments, the alignment and general position of the anchor structure is guided by the cable until each of the legs is carried over a corresponding anchor on the water bed.

[0099] According to some embodiments, the anchor structure is secured to the water bed at block 814. According to some embodiments, each leg of the anchor structure with its respective foot pad covers a corresponding anchor on the water bed as the anchor structure is aligned over the various anchors as it is lowered into position. In some embodiments, a series of pulleys and cams located within each leg of the anchor structure are used to tension the cables and thus rigidly attach the anchor structure to the water bed.

[0100] 9 shows a flowchart 900 describing another method for deploying a hydrodynamic system in a body of water, according to some embodiments. The method involves anchoring the system to the floor of an underwater environment, where an anchor structure is first attached to the water floor, and then the hydrodynamic system is submerged and attached to the anchor structure. The operations, functions, or acts described in each block of flowchart 900 may be performed in an order different than that shown, and any two or more blocks may be performed simultaneously in some circumstances.

[0101] According to some embodiments, anchors are secured to the water bed at block 902. Any type of anchor may be used, such as T-anchors, screw anchors, plate anchors, or injection embedment anchors. The anchors may be arranged in a specific pattern to match the position of the legs from the anchor structure that are aligned on the anchor.

[0102] According to some embodiments, the cables are secured to the anchors at block 904. The cables may be fastened or welded to each anchor before the anchors are driven into the waterbed. The cables may be long enough to extend from the waterbed above the water surface so that the other ends of the cables can be used with an anchor structure, such as anchor structure 104.

[0103] According to some embodiments, at block 906, the cables attached to the anchors are threaded through the legs of the anchor structure. The legs of the anchor structure include a hollow portion to allow the cable of a given anchor to be threaded through one of the legs of the anchor structure. In some instances, the cable passes through the distal end of a given leg and emerges at the opposite end of the leg.

[0104] According to some embodiments, at block 908, the anchor structure alone is guided over the anchor in the water. The anchor structure may be guided via a cable that extends through one or more of the legs of the anchor structure. The cable may be held taut while the anchor structure slowly sinks into the water. According to some embodiments, the alignment and general position of the anchor structure is guided by the cable until each of the legs is carried over a corresponding anchor on the water bed.

[0105] According to some embodiments, at block 910, an anchor structure is secured to the water bed. According to some embodiments, each leg of the anchor structure with its respective foot pad covers a corresponding anchor on the water bed as the anchor structure is aligned over the various anchors as it is lowered into position. In some embodiments, a series of pulleys and cams located within each leg of the anchor structure are used to tension the cables and thus rigidly attach the anchor structure to the water bed.

[0106] According to some embodiments, the buoyancy of the hydrodynamic device is reduced at block 912. Buoyancy can be reduced through the use of one or more ballast tanks on the hydrodynamic device, such as a portion of a duct. Certain ballast tanks can be partially or completely filled with water to alter the weight of the hydrodynamic device, affect the rate at which the hydrodynamic device sinks in water, or cause the hydrodynamic device to remain in a given position below the water surface.

[0107] According to some embodiments, at block 914, the hydrodynamic device is guided underwater to an anchor structure in the water bed. The hydrodynamic device may be manually guided via one or more undersea divers to help position the hydrodynamic device as it slowly sinks in the water. In some embodiments, one or more of the rotors on the hydrodynamic device may rotate to provide some thrust to the whole system to move through the water. In some embodiments, ballast tanks arranged in different parts of the hydrodynamic device may be filled with air or water to change the center of gravity and center of buoyancy of the hydrodynamic device and thus affect how it moves through the water. Each of these techniques may be used together in any combination to guide the hydrodynamic device underwater onto an anchor structure.

[0108] According to some embodiments, at block 916, the hydrodynamic device is secured to an anchor structure. For example, a hydrodynamic device, such as hydrodynamic device 100 or hydrodynamic device 800, may include a large duct to allow water to pass through the duct and spin a rotor within the duct. The cylindrical shape of the duct may rest on a cradle coupled to an anchor structure, such as anchor structure 104. According to some embodiments, the weight of the hydrodynamic device allows it to remain within the cradle of the anchor structure when aligned and positioned on the anchor structure in the water. According to some other embodiments, one or more mechanical locking mechanisms are used to secure the hydrodynamic device to the anchor structure.

[0109] Numerous specific details have been described herein to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. In other instances, well-known operations, components, and circuits have not been described in detail so as not to obscure the embodiments. It will be further understood that specific structural and functional details disclosed herein are representative examples and do not necessarily limit the scope of the embodiments. In addition, although the subject matter has been described in language specific to structural features and / or method acts, it will be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described herein. Rather, the specific features and acts described herein are disclosed as exemplary forms of implementing the claims.

Claims

1. A housing for a hydrodynamic system, comprising a duct having an inner surface and an outer surface that define a central flow path, the duct having a substantially circular cross-section, wherein the central flow path has a first diameter, and the duct further comprises a first opening having a second diameter and a second opening having a third diameter, both the second diameter and the third diameter being larger than the first diameter; a compartment between the inner surface and the outer surface of the duct, the compartment accommodating at least one mechanical component connected to a generator; at least one ballast tank located in the compartment; and a carriage slidable on the outer surface of the duct and the slidable carriage is configured to be connected to an anchor via an anchor cable, the housing.

2. The housing according to claim 1, wherein the first diameter of the central flow path is that of a midpoint between the first opening and the second opening, and the first diameter is the smallest diameter within the central flow path.

3. The housing according to claim 2, wherein the diameter of the inner surface of the duct increases parabolically between the first diameter and the second diameter and between the first diameter and the third diameter.

4. The housing according to claim 2, wherein the second diameter is substantially the same as the third diameter.

5. The housing according to claim 4, wherein the second diameter and the third diameter are between about 25 feet (7.6 meters) and about 35 feet (10.6 meters), and the first diameter is between about 15 feet (4.5 meters) and about 25 feet (7.6 meters).

6. The housing according to claim 1, wherein the outer surface of the duct has a substantially flat wall along its length between the first opening and the second opening.

7. The housing according to claim 1, wherein the compartment is an annular compartment extending around the duct.

8. The housing according to claim 1, further comprising a plurality of ballast tanks located in the compartment, wherein the plurality of ballast tanks are independently operable.

9. The housing according to claim 1, further comprising a first grid disposed above the first opening and a second grid disposed above the second opening.

10. The housing according to claim 9, wherein each of the first grid and the second grid includes a repeating square grid pattern, a repeating diamond pattern, or a repeating triangular pattern.

11. The housing according to claim 9, wherein each of the first grid and the second grid includes stainless steel.

12. The housing according to claim 9, wherein each of the first grid and the second grid has a convex contour.

13. The housing according to claim 1, wherein the compartment is completely sealed and watertight.

14. The housing according to claim 1, further comprising one or more struts connected to the inner surface of the duct in the central flow path, wherein the one or more struts support one or more rotor assemblies.

15. The housing according to claim 14, wherein two struts are connected between the inner surface of the duct and a common shaft, and wherein two rotor assemblies are connected to opposite ends of the common shaft.

16. The housing according to claim 15, wherein the two rotor assemblies are configured to rotate in opposite directions.

17. The housing according to claim 1, further comprising an electrochemical separator configured to generate chlorine gas from salt using electricity from the generator, wherein the chlorine gas is directed to the inner surface of the duct.

18. The housing according to claim 1, wherein the length of the duct is between about 45 feet (13.7 meters) and about 55 feet (16.7 meters).

19. The housing according to claim 1, wherein the duct and the compartment include any one of a composite material, mild steel, or stainless steel.

20. The housing according to claim 1, wherein the generator is disposed within the compartment.

21. The housing according to claim 1, further comprising a platform connected to the outer surface of the duct and extending along the length of the duct.

22. The housing according to any one of claims 1 to 21, further comprising a rim cover over the outside of the first opening or the second opening.

23. The housing according to claim 22, wherein the rim cover is removable and protects an annular recess.

24. The housing according to claim 23, wherein the annular recess is configured to hold one or more cables.

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