Patent Application
20240260528
The present invention relates to apparatuses for and methods of growing aquatic plants and macroalgae, such as seaweed and kelp, in a large and/or natural body of water.
U.S. Pat. No. 7,905,055 discloses an automated ocean farm that includes a plant support means such as a grid, with a submersible towing system incorporating means for navigation of the support grid in the open ocean, and means for positioning of the support grid in a first surfaced position for sunlight exposure of the plants and a second submerged position for nutrient gathering by the plants. Referring to FIG. 1, a farm 10 according to the '055 patent includes strong neutral-buoyancy rope 12 with two similar ropes 14 trailing back with additional neutral buoyancy ropes 16 stretched between them to create a support grid. The support grid may be supported by buoys at spaced intervals to provide a substantially neutrally buoyant grid. Marine plants 18 are anchored to the grid at periodic intervals (e.g. 1 meter spacing along the ropes for California Giant Kelp with 10-meter down-current spacing to accommodate the plants at harvestable size and 0.2 to 0.4 m for tropical seaweeds such as Eucheuma spp and Kappaphycus spp.). The grid is propelled by a submersible towing system. Two towing boats 20 and 22 provide a first element of the towing system. Two reaction boats 24 and 26 provide a second element of the towing system to create and maintain tension in the lines by relative positioning with respect to the two tow boats.
This “Discussion of the Background” section is provided for background information only. The statements in this “Discussion of the Background” are not an admission that the subject matter disclosed in this “Discussion of the Background” section constitutes anticipatory prior art to the present disclosure, and no part of this “Discussion of the Background” section may be used as an admission that any part of this application, including this “Discussion of the Background” section, constitutes prior art to the present disclosure.
In one aspect, the present invention concerns an apparatus for growing aquatic plants or macroalgae at variable depths, comprising an upper or floating ring, a lower or submerged ring, and one or more cables, ropes or chains connecting the lower ring to the upper ring. The upper ring comprises (i) a material having a density less than that of water or (ii) an air-filled ring, bladder, buoy or vessel adapted to float on a surface of a body of water. The lower ring has or is ballasted to have a density greater than that of fresh or sea water. Each of the upper ring and the lower ring comprises a material on its outermost surface that resists damage by water. The lower ring may further comprise a support to which the aquatic plants or macroalgae can be secured or on which the aquatic plants or macroalgae can be grown. The support may comprise a plurality of parallel lines or wires, a plurality of radially-distributed lines or wires, or a mesh or grid.
In various embodiments, each of the upper and lower rings independently has a circular, toroidal, oval, square, rectangular, triangular or other regular geometric shape, and may have either (i) a width and length or (ii) a diameter of from 10 m to 1200 m. In some embodiments, each of the upper and lower rings independently comprises polyethylene or polypropylene, and may have a tube or pipe diameter of 0.05-5.00 m. In various embodiments, each cable or ropes or chain comprises e.g. polyethylene, polypropylene, carbon fiber composite or steel, and may have a length of from 50 m to 3000 m.
In many embodiments, the apparatus further comprises one or more winches on the upper ring. Each winch is configured to raise and lower a corresponding cable or ropes or chain, and may be motorized (e.g., the apparatus further comprises a motor configured to operate the corresponding winch) or manually operated (e.g., the winch further comprises an arm attached to a rotatable axle of shaft, and a handle attached to the arm). In some embodiments, the lower ring may comprise one or more negative lift hydrofoils.
Another aspect of the present invention concerns a self-powered apparatus for growing aquatic plants or macroalgae with depth cycling, comprising a platform, a floating support to which the platform is affixed, one or more winches on the platform, one or more motors on the platform, and a green or renewable power source on or supported by the platform. The floating support is configured to physically support the platform on a body of water. A corresponding cable or ropes or chain is attached to each winch. The motor(s) are configured to operate the winch(es). The power source provides electrical power directly or indirectly to the motor(s).
In some embodiments, the apparatus further comprises a battery and an optional power controller. The battery stores the electrical power from the renewable power source. The power controller is configured to provide the electrical power (i) from the renewable power source to the battery and (ii) from the battery to the motor(s).
In other or further embodiments, the apparatus may further comprise a controller configured to (i) control the motor(s), to raise or lower the cable or ropes or chain attached to the corresponding winch by predetermined amounts and/or at predetermined times, and (ii) control the power controller to provide the electrical energy from the battery to the motor(s) when the renewable power source is not producing electricity. The apparatus may also further comprise (i) a light sensor configured to provide light data to the controller for comparison with one or more predetermined thresholds (e.g., corresponding to an amount or intensity of light associated with a sunrise and/or a sunset), (ii) a weather sensor configured to provide weather data to the controller (e.g., for comparison with one or more thresholds corresponding to a weather event that might make it dangerous to bring the aquatic plants or macroalgae to the surface), and/or (iii) a temperature sensor configured to provide a temperature of the water at the lower ring, (iv) a current meter that can measure a velocity of the water at either of the rings, (v) a motion sensor configured to determine a distance that or a rate at which the upper or floating ring moves (e.g., for comparison with one or more thresholds corresponding to a rough sea, which could cause damage to the apparatus or the aquatic plants or macroalgae if brought to the surface), or (vi) a depth and/or pressure sensor for measuring the depth of the upper or lower ring. In various embodiments, the apparatus comprises the light sensor and/or the weather sensor. The weather sensor can be selected from a temperature sensor, a precipitation sensor, and a wind sensor.
Yet another aspect of the present invention concerns a controller for growing aquatic plants or macroalgae with depth cycling, comprising a processor or core configured to send instructions to other components and/or circuit blocks in the controller over an internal bus, a memory configured to receive, record, store and/or provide data, programming and/or the instructions, power control circuitry configured to receive power from an external source and provide power to the other components and/or circuit blocks over power supply lines, a receiver and/or a transmitter, and function logic configured to operate one or more motors to raise or lower one or more cables or ropes or chains on a corresponding one or more winches (e.g., operably connected to the motor) by one or more (pre)determined amounts at one or more (pre)determined times. The receiver is configured to receive external signals, and the transmitter is configured to transmit internal information (e.g., from the memory and/or the processor or core to an external device). Thus, many embodiments of the controller further comprise (i) a timer configured to provide a timing signal to the other components and/or circuit blocks and/or (ii) an antenna configured to receive the wireless signals from an external source (e.g., a computer or other digital processing device configured to program the controller) and/or broadcast the internal information to one or more external devices.
In some embodiments, the controller may further comprise (i) a weather detection block configured to receive weather data from a weather sensor and (ii) a motion detection block configured to receive motion data from a motion sensor. The weather sensor may include a temperature sensor, a light sensor, a precipitation sensor, or a wind sensor. The controller may be adapted for use with the apparatus described above or a method of growing seaweed and/or aquatic plants with depth cycling (see below).
Still another aspect of the present invention concerns a method of growing seaweed and/or aquatic plants, comprising determining whether an ambient or environmental light exceeds a first predetermined threshold amount or intensity of light, raising the seaweed and/or the aquatic plants from a first (e.g., lowermost) depth in a body of water to a second, shallower depth in the body of water when the ambient or environmental light exceeds the first predetermined threshold amount or intensity of light, determining whether the ambient or environmental light decreases below a second predetermined threshold amount or intensity of light, and lowering the seaweed and/or the aquatic plants to the first depth when the ambient or environmental light decreases below the second predetermined threshold amount or intensity of light. The second depth depends on whether any conditions are met that would be dangerous for the seaweed and/or the aquatic plants to come to a surface of the body of water. The first predetermined threshold amount or intensity of light may correspond to a sunrise, and the second predetermined threshold amount or intensity of light may correspond to a sunset. The body of water may be a lake, bay, inlet, river, gulf, sea or ocean. The present method is useful for implementing depth cycling when growing seaweed and/or aquatic plants, where the seaweed and/or aquatic plants is brought to the surface during daytime, and taken to a depth where the water is cooler and more nutrient-rich during nighttime.
In general, when no conditions are met that would be dangerous for the seaweed and/or the aquatic plants to come to the surface of the body of water, the second depth is an upper or uppermost position, and when one or more conditions are met that would be dangerous for the seaweed and/or the aquatic plants to come to the surface of the body of water, the second depth is an intermediate position. The intermediate position is lower/deeper than the upper or uppermost position. For example, the first (lowermost) depth may be 100-1000 m, the intermediate position may be 25-100 m, and the upper or uppermost position may be 0.1-25 m.
The method may further comprise determining whether one or more conditions are met that would be dangerous for the seaweed and/or the aquatic plants to come to the surface of the body of water. The conditions may include one or more of rough seas, bad weather, and navigation hazards.
In many embodiments, the seaweed and/or the aquatic plants are on or affixed to a ring, and the ring is attached to one or more cables or ropes or chains. In such embodiments, raising the seaweed and/or the aquatic plants may comprise taking in or winding the cable(s) or ropes or chain(s), and lowering the seaweed and/or the aquatic plants may comprise letting out or releasing the cable(s) or ropes or chain(s).
Yet another aspect of the present invention concerns a second apparatus for growing seaweed or aquatic plant(s), comprising a bow pipe, a stern pipe, a plurality of ribs, and one or more nets on or fixed to the ribs. The net(s) may have different mesh sizes, depending on the seaweed species. Each of the ribs is connected to each of the bow pipe (e.g., at a first end of the rib) and the stern pipe (e.g., at a second, opposite end of the rib). Each net is substantially submerged in the water, and forms a volume or space in which the seaweed or aquatic plant(s) grow.
In some embodiments, each of the bow pipe, the plurality of ribs, and the stern pipe may comprise a hollow polyethylene/polypropylene pipe. Each of the bow pipe, the plurality of ribs, and the stern pipe may have a length of at least 10 m (e.g., 10-100 m or more).
The second apparatus may further comprise first ballast in or attached to at least one net and/or second ballast on or attached to at least one of the bow pipe and the stern pipe. The first ballast is relatively small, and is adapted to keep the net in the water and/or to ensure that there is some space or volume in the net (e.g., between adjacent ribs). The second ballast is relatively large, and is adapted to facilitate lowering, sinking or submerging at least one end of the apparatus in the body of water.
In some embodiments, the apparatus may further comprise a pump configured to transfer water into and/or out of at least one of the bow pipe, the ribs, and the stern pipe. In other or further embodiments, the apparatus may further comprise an upper net on the ribs, configured to retain the seaweed or aquatic plant(s) in the space or volume. In yet other and/or further embodiments, the apparatus may further comprise (i) one or more ropes connected to at least one of the bow pipe, the plurality of ribs, and the stern pipe, (ii) a corresponding one or more winches configured to pull in or let out one or more ropes, and (iii) a corresponding one or more motors configured to operate the one or more winches. In this and the other aspects of the present invention, the winch(es), the motor(s) and the rope(s) (or the cable[s] or ropes or chain[s]) may be in a 1:1:1 relationship.
A still further aspect of the present invention concerns a method of growing and harvesting aquatic plants or seaweed, comprising seeding the aquatic plants or seaweed in one or more nets on a plurality of ribs, submerging the one or more nets and the seaweed or aquatic plants in a body of water, growing the seaweed or aquatic plants to partially or substantially fill the volume or space, and harvesting the seaweed or aquatic plants from the net(s). Each of the ribs is connected to a bow pipe and a stern pipe. The net(s) form a volume or space (e.g., between adjacent ribs) in which the seaweed or aquatic plants grow. The seaweed or aquatic plants may be grown to fill at least half of the volume or space in the net, although the invention is not limited in such a manner. The seaweed or aquatic plants are harvested using an aquatic vehicle adapted to travel over the net(s), the ribs, and at least one of the bow pipe and the stern pipe.
Yet another aspect of the present invention concerns an aquatic vehicle adapted to seed and harvest aquatic plants or macroalgae in a floating (and optionally submersible) net on or fixed to a plurality of ribs, comprising a vessel spanning two or more of the ribs, and a plurality of float segments on each of a port side and a starboard side of the vessel. Each of the ribs connected to a bow pipe and a stern pipe, and the net forms a volume or space between adjacent ribs for the seaweed or aquatic plants. Each of the float segments can be raised and lowered so as to pass over at least one of the bow pipe and the stern pipe, and optionally to pass through the space between adjacent ribs. The spaces in which each set of float segments (on opposite sides of the vessel) may be separated by 2-5 ribs.
In some embodiments, the aquatic vehicle comprises a multi-hulled vessel, such as a catamaran with a deck. The deck may have a seaweed access area thereon or therethrough. The catamaran may be 3-20 m wide and 3-20 m long. The deck may be 3-20 m wide and 1.5-10 m long. In other or further embodiments, the aquatic vehicle may comprise at least three float segments on each of the port and starboard sides.
In some embodiments, the aquatic vehicle may further comprise at least one retractable float piston connected to each of the float segments. The retractable float pistons raise the corresponding float segment over the bow pipe and/or the stern pipe, and lower the corresponding float segment back onto the water after the float segment traverses/crosses the bow/stern pipe. The aquatic vehicle may be adapted for use with the second apparatus or the method of growing and harvesting described above.
Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the following embodiments, it will be understood that the descriptions are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents that may be included within the spirit and scope of the invention. Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be readily apparent to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to unnecessarily obscure aspects of the present invention. Furthermore, it should be understood that the possible permutations and combinations described herein are not meant to limit the invention. Specifically, variations that are not inconsistent may be mixed and matched as desired.
The technical proposal(s) of embodiments of the present invention will be fully and clearly described in conjunction with the drawings in the following embodiments. It will be understood that the descriptions are not intended to limit the invention to these embodiments. Based on the described embodiments of the present invention, other embodiments can be obtained by one skilled in the art without creative contribution and are in the scope of legal protection given to the present invention.
Furthermore, all characteristics, measures or processes disclosed in this document, except characteristics and/or processes that are mutually exclusive, can be combined in any manner and in any combination possible. Any characteristic disclosed in the present specification, claims, Abstract and Figures can be replaced by other equivalent characteristics or characteristics with similar objectives, purposes and/or functions, unless specified otherwise.
The term “length” generally refers to the largest dimension of a given 3-dimensional structure or feature. The term “width” generally refers to the second largest dimension of a given 3-dimensional structure or feature. The term “thickness” generally refers to a smallest dimension of a given 3-dimensional structure or feature. The length and the width, or the width and the thickness, may be the same in some cases. A “major surface” refers to a surface defined by the two largest dimensions of a given structure or feature, which in the case of a structure or feature having a circular surface, may be defined by the radius of the circle.
For the sake of convenience and simplicity, the terms “tube,” “hose,” “conduit,” “pipe” and grammatical variations thereof are, in general, interchangeable and may be used interchangeably herein, but are generally given their art-recognized meanings. Wherever one such term is used, it also encompasses the other terms. Similarly, for convenience and simplicity, the terms “rope,” “line,” and “cable” may be used interchangeably herein. Wherever one such term is used, it also encompasses the other terms.
In addition, for convenience and simplicity, the terms “part,” “portion,” and “region” may be used interchangeably but these terms are also generally given their art-recognized meanings. Also, unless indicated otherwise from the context of its use herein, the terms “known,” “fixed,” “given,” “certain” and “predetermined” generally refer to a value, quantity, parameter, constraint, condition, state, process, procedure, method, practice, or combination thereof that is, in theory, variable, but is typically set in advance and not varied thereafter when in use.
Both the upper and lower rings 210a-b should comprise a material that resists damage by water as or on its outermost surface. As shown in
When designed for large-scale aquatic mariculture, the upper and lower rings 210a-b may independently have (i) a width and length or (ii) a diameter of from 50 m to 1200 m, or any value or range of values therein (e.g., 100-300 m), although the invention is not limited to such values. For example, in smaller-scale aquatic mariculture, the width and length or diameter of the upper and lower rings 210a-b may be on the order of 10-100 m, although the invention is not limited to these values, either. Smaller platforms may benefit from having a single rope, line or cable over part or all of the distance between the upper and lower rings, to avoid the prospect of tangling the cable or ropes or chain over the full deployment depth.
The outer tube diameter of the upper and lower rings 210a-b may be in the range of 0.05-10 m, inclusive, depending on the width and length or diameter of the upper and lower rings 210a-b and the material of the rings 210a-b. When the upper and lower rings 210a-b are in the form of a tube or pipe, the tube or pipe may have a hollow interior or be solid. For example, when the upper and lower rings 210a-b have width and length or diameter of 10-50 m, the diameter of the upper and lower rings 210a-b may independently be 0.30-1.50 m, or any value or range of values therein, although the invention is not limited to such values. Similarly, when the upper and lower rings 210a-b have a width and a length (or a diameter) of 100-500 m, the thickness of the upper and lower rings 210a-b may independently be 0.35-5.00 m, or any value or range of values therein, although the invention is not limited to these values, either. Depending on the material, a pipe diameter (thickness) above a certain value may not provide much additional rigidity. For example, high-density polyethylene (HDPE) and polypropylene rings having a thickness of 0.3-0.6 m can withstand ocean conditions including 10- to 12-m waves and wind speeds of up to 200 km/h. As a result, there may not be much additional benefit from using HDPE or polypropylene having a diameter of more than 3 m.
In some embodiments, the lower or submerged ring 210b may comprise a negative lift hydrofoil. In other words, at least some parts of the lower or submerged ring 210b may have a cross-sectional shape configured to provide negative lift in the presence of a current in the water. In such embodiments, the negative lift can help anchor the apparatus 200 in place, or at least reduce its movement, in the presence of a current (such as can arise during relatively high winds or a storm). For example, the cross-sectional shape of a negative lift hydrofoil may resemble a cross-section of an inverted or upside-down airplane wing, as shown in
Although four cables or ropes or chains 220a-d are shown in
The cables or ropes or chains 220a-d may be independently secured to the upper and/or lower ring 210a-b by looping them around the ring and tying, fastening an end of the cable or ropes or chain to itself with a clamp or similar fastening device, or soldering/fusing the end of the cable or ropes or chain to itself. For example, polyethylene (PE) ropes may form an “eye” through which the upper and/or lower ring 210a-b may be fed, and the end of each polyethylene rope may be secured to itself with a metal crimp. Similarly, a rope made of natural materials can form an eye with a PE overmolding in the eye region, to take advantage of PE's “self-lubricating” properties. Alternatively, the cables or ropes or chains 220a-d may be secured to the upper and/or lower ring 210a-b by passing the end of the cable or ropes or chain through a hole or other opening in the ring and forming a knot having a size larger than the opening, or by securing it to an object such as a plate or bar having at least one diameter greater than that of the opening. In a further alternative, the rings 210a-b may be fitted with fastening rings to which the cables or ropes or chains are secured. For example, the material of the ring 210a or 210b may be passed through used automobile, motorcycle or truck tires, then the ends of the ring material may be soldered or fused to each other, and the cables or ropes or chains 220a-d secured to the tires. Other round, ring-shaped materials can also be used to secure the cables or ropes or chains 220a-d to the upper and lower rings 210a-b.
Referring now to
The lower ring 210b is at a depth of x*H, where x has a value of <1. The value of x depends on various factors, such as the current at depth H, the mass and/or density of the lower ring 210b, any twisting of the cables or ropes or chains 220a-d, etc. The apparatus 200 may be tethered or anchored in place using a cable, rope or chain or line 230, secured to the upper ring 210a and at the unseen end of the cable, rope or chain or line 230 to an anchor, a buoy, a larger platform, another apparatus similar or identical to the apparatus 200, etc. Alternatively, the cable, rope or chain or line 230 may be secured to the lower ring 210b instead of the upper ring 210a.
The aquatic plants 240 may be grown on the lower ring 210b by affixing the plants 240 to the lower ring 210b, for example by tying the plants 240 to the lower ring 210b (e.g., using string or rope), binding the plants 240 to the lower ring 210b (e.g., using a polymeric and optionally biodegradable wrap or tape, a zip tie or equivalent binder), etc. Alternatively, when the plants 240 are sufficiently large, they can simply be hung on or wrapped around the lower ring 210b.
In some embodiments, the lower ring 210b may contain a support to which the plants 240 may be secured or on which the plants 240 may be grown. As shown in
The cables or ropes or chains 320a-c pass through an opening in the center of the upper ring 310a, and are secured to the lower ring 310b by loops 325a-c. The ends of the cables or ropes or chains 320a-c are secured to the loops 325a-c using fastening devices and/or techniques described herein. To ensure that the cables or ropes or chains 320a-c adequately clear the inner surface of the upper ring 310a, the cables or ropes or chains 320a-c may pass through and/or be suspended above the winches 330a-c by a corresponding plurality of pulleys over the opening in the upper ring 310a, which may be secured to a frame or trellis on and/or affixed to the upper surface of the upper ring 310a.
In use, the winches 330a-c raise and lower the cables or ropes or chains 320a-c concurrently or substantially concurrently. For example, during the daytime, the aquatic plants need sunlight to grow. Accordingly, during good weather, the lower ring 310b is maintained at a depth of about 0.3-25 m, from around dawn to around dusk. At night, the aquatic plants may be lowered to cooler and/or more nutrient-rich water (for example, to a depth of 100-500 m or more, from around dusk or sunset to around dawn or sunrise). The depths to which the lower ring 310b is raised, lowered or maintained may depend on, for example, the width and length (or diameter) of the apparatus 300 or upper ring 310a, the lengths of the cables or ropes or chains 320a-c, the water temperature at various depths, the nutrient profile in the water at various depths, etc. However, generally, the larger the upper ring 310a, the greater the depth(s) of the lower ring.
The user grasps the handle 745 and rotates the arm 740 and the axle 715 clockwise to pull in or wind the cable 720 onto the spool 730 and raise the lower ring (not shown in
An exemplary on-board power and control system 400 is shown in
The power controller 420 is configured to provide electrical energy from the green power source 410 to the battery 430 (for storage) and the switch 440 and controller 500 for operation of the winch motor and other electrical devices in the system 300′ (described elsewhere). The power controller 420 is also configured to provide electrical energy from the battery 430 to the switch 440 and controller 500 when the green power source 410 is not producing electricity.
The switch 440 connects electrical power from the power controller to the winch motor 350′ and, if needed, to the brake 365. The switch 440 may comprise a double pole double throw switch, but the invention is not limited to this type of switch. The switch 440 may be controlled (e.g., opened or closed) by a control signal from the controller 500. One or more additional switches may be present to control the supply of electrical power to other devices in the system 300′, and the additional switches may receive an independent control signal from the controller 500.
An exemplary controller 500 is shown in
The memory receives, records, stores and/or provides data, usually in response to one or more instructions from the processor/core 510. For example, the memory may store programming and/or instructions for the processor/core 510 and/or the function logic 560, data from and/or threshold values for the optional weather detection block 570 and/or motion detection block 580, etc.
The power control circuitry 530 may receive power from an external source (e.g., a battery) and may be externally connected to a ground potential. The power control circuitry 530 may provide power to the other circuit blocks over power supply lines 535. The power control circuitry 530 may also connect the external ground potential to a ground plane in the controller 500, wired similarly to the power supply lines 535. In some embodiments, the power control circuitry 530 powers down some or all circuit blocks on the controller 500. For example, the power control circuitry 530 may disconnect the external power from one or more of the processor/core 510, the memory 520, the function logic 560, and/or the optional weather detection and motion detection blocks 570 and 580. Power may be provided to the receiver/transmitter 540 and/or timer 550, except for extreme circumstances, such as a lack of external power, weather and/or motion conditions that put the winch 330 and/or motor 350 at risk of being submerged, etc.
The timer 550 is conventional, and is configured to provide a timing signal to the circuit blocks in the controller 500 that can function in response to the timing signal (e.g., the processor/core 510, the memory 520, the receiver/transmitter 540, and/or the function logic 560). Either the timer 550 or the function logic 560 may include real-time clock logic that provides a real-time clock function. The function logic 560 may be programmed to operate the motor 350 raise or lower the cables or ropes or chains 320 using the winches 330 by predetermined amounts at predetermined times. For example, the function logic 560 may be programmed to raise the lower ring 310b to a relatively shallow depth (e.g., 0.5-25 m) at a time from shortly before, at or after sunrise (e.g., sunrise, plus/minus 10 minutes), and lower the lower ring 310b to a relatively deep depth (e.g., 100-500 m) at a time from shortly before, at or after sunset (e.g., sunset, plus/minus 10 minutes). Given the known or easily determinable relationship between the motor speed and the rate that the cable or ropes or chain 320 travels, one can easily determine how long the motor must operate the pull in or let out a predetermined length of the cable or ropes or chain 320. The function logic 560 can also be programmed to instruct the motor 350 which direction to operate (e.g., a first direction to pull in the cable or ropes or chain 320 and raise the lower ring 310b, or a second, opposite direction to let out the cable or ropes or chain 320 and lower the lower ring 310b).
The optional weather detection and motion detection blocks 570 and 580 may receive sensor data from optional weather and motion sensors 575 and 585, respectively. For example, the weather sensor(s) 575 may include a temperature sensor, a light sensor, a precipitation sensor, a wind sensor, a pressure sensor for sensing hydrostatic depth of one or more rings, a water current sensor (which may sense the velocity or current speed of the water at either the upper ring or the lower ring), etc. Data from one or more of the weather sensors 575 may be compared to one or more corresponding threshold values in the weather detection block 570, and the function logic 560 may provide a signal (or “flag”) to the processor/core 510 to modify the instructions, execute different instructions, or send a different instruction to the motor 350 or other circuit block on the controller 500 (e.g., power control circuitry 530). For example, when the temperature sensor senses a temperature below a first threshold temperature (e.g., 0°) or above a second threshold temperature (e.g., 40°), the light sensor detects an amount of daylight below a first threshold intensity (e.g., 20% of the average daylight intensity for that geographic location on a cloudless day at noon on the winter solstice) or above a second threshold intensity (e.g., 80% of the average daylight intensity for that geographic location on a cloudless day at noon on the summer solstice), the precipitation sensor senses the presence of precipitation, the current sensor (especially at the upper ring) senses a water current above a threshold, and/or the wind sensor senses a wind speed above a first threshold (e.g., 15 m/sec) or a second threshold (e.g., 25 m/sec), the weather detection logic can send a signal to the processor/core 510 that a weather excursion is occurring, indicating that it may not be safe to bring or keep the lower ring 310 near the water surface. Depending on the excursion and/or the number and/or severity of the excursion(s), the processor/core 510 may instruct the motor to pull in or let out a length of the cables or ropes or chains 320 sufficient to raise or lower the lower ring 310b to a depth of, e.g., 25-100 m below the surface.
In one example, a seaweed growing system includes a light sensor 575 and light detector 570 that responds to a threshold light level (e.g., 5% of the average daylight intensity for that geographic location on a cloudless day at noon, on essentially any day or time period), or a timer that is triggered at predetermined times of day (i.e., known times of sunrise and sunset) to cause the controller 500 to send a command to the motor 350 to raise the seaweed shortly before or when it is light (i.e., at sunrise) and lower the seaweed before, during or after sunset, to gain nutrients in lower-lying waters at night. This system may be automated, to avoid any need for human intervention (e.g., twice a day to operate the motor to raise and lower the lower ring, or to manually do so). Alternatively, the light sensor may comprise an analog-to-digital (A/D) converter 590, configured to receive one or more analog inputs from the solar panel(s) 410 and provide a digital output to the light detector 570 and/or logic 560 for comparison with one or more predetermined thresholds.
Similarly, the motion detection block 580 may receive a signal from conventional motion sensor 585 that the upper ring 310a is moving above a predetermined distance (e.g., up and down on waves) or at a rate greater than a predetermined threshold (e.g., >1 m/s laterally, due to current), and the logic and/or circuitry in the motion detection block 580 may send a signal to the processor/core 510 that a motion excursion is occurring, indicating that it may not be safe to bring or keep the lower ring 310b near the water surface, or that action should be taken to prevent the apparatus 300 from drifting too far away from its designated location. Depending on the excursion and/or its severity, the processor/core 510 may instruct the motor to pull in or let out a length of the cables or ropes or chains 320 sufficient to raise or lower the lower ring 310b to a depth of, e.g., 100-500 m below the surface.
Once the functions and operating parameters are known, it is within the level of ordinary skill in the art to design and make the controller 500.
Referring back to
When the ambient or environmental light exceeds the sunrise threshold, the control system 400 and/or controller 500 determine at 620 whether any conditions are met that would be dangerous for the plants or macroalgae to come to the surface, such as rough seas, bad weather, one or more navigation hazards (e.g., a ship or other vessel passing nearby), etc. When there are no such conditions, the lower ring is raised to an upper position (e.g., an uppermost depth or level, such as a depth of 1-25 m) at 630 so that the plants or macroalgae can be safely exposed to sunlight. When there are conditions that are dangerous for aquatic plants or macroalgae (or for other vessels on the water), the plants or macroalgae may be brought to an intermediate position (e.g., an intermediate depth or level, such as a depth of 25-100 m) at 635, where the water is safer for the plants or macroalgae, and where they will still receive enough sunlight to survive. For example, it is known that certain species of macroalgae can suffer and even begin to die if they do not receive a sufficient amount of sunlight within a 24-hour period. The method may periodically or continuously re-determine at 620 whether the dangerous or hazardous conditions still exist. If so, the plants or macroalgae may remain at the intermediate position at 635, and if not, the lower ring may be raised to the upper position at 630.
At 640, when the light detector 570 or the logic 560 indicates that the ambient or environmental light has decreased below a predetermined threshold amount or intensity of light corresponding to a typical sunset, the lower ring is lowered to the lower position (e.g., a lowermost depth or level, such as a depth of 100-1000 m) at 650, thereby closing the loop or cycle of the method 600. In some embodiments, when it is safe for the plants or macroalgae to remain at the surface (e.g., the upper position) overnight, the method may count a predetermined number of times (e.g., 2 or 3) that the sunset threshold is crossed at 640 before returning the lower ring to the lower position at 650.
The connecting lines 846a-g may pass through the spreader bar 844. For example, the spreader bar 844 may have a number of holes or openings therethrough, and each of the connecting lines 846a-g may pass through a corresponding one of the holes or openings. Alternatively, each of the connecting lines 846a-g may comprise a first line between the spreader ring 842 and the spreader bar 844, and a second line between the spreader bar 844 and the lower ring 815. Each of the first and second lines is conventionally joined to the spreader bar 844.
The apparatus 800 works in substantially the same way as the apparatuses 300 and 300′ in
Thus, in various embodiments, the apparatus for growing aquatic plants or macroalgae includes only a single winch. The single winch may have a spool with a cable or ropes or chain having a length of 100-3000 m thereon, and the end of the cable or ropes or chain not affixed to the spool may be joined to a bridle. The bridle may include a spreader and a plurality of distributed ropes or lines connected thereto or passing therethrough. The ropes or lines may have a length of 1-10 m between the lower ring and the spreader. In such embodiments, the lower ring may have a width, length or diameter of 10-1200 m, or any value or range of values therein (e.g., 100-500 m).
In further embodiments, the lower ring 815 in the apparatus 800 of
The lower ring 815 may contain a support on which the plants/macroalgae may be grown, for example as shown in
Another alternative apparatus 900 for growing aquatic plants and macroalgae is shown in
The upper ring 910 is similar or identical to upper rings in other exemplary apparatuses disclosed herein, and can operate similarly to a conventional buoy. As with the apparatus 800 in
The intermediate lower ring 950 is connected to the main lower ring 960 by a plurality of support lines or wires 955. The support lines or wires 955 may be connected at one end to the connecting rings or loops 952 around the intermediate lower ring 950, and at the other end to similar connecting rings or loops 952 around the main lower ring 960. The support lines or wires 955 generally function as a mechanical support to which the aquatic plants or macroalgae can be attached and on which they can grow. In one embodiment, the lower ring 950 may be ballasted internally or externally to have a net density greater than water, such that it provides ballast to enable the lower ring structure to sink. Such an embodiment may also have the main lower ring 960 comprising a material like HDPE with a net density less than that of water, resulting in net buoyancy. When brought to the surface, such a configuration may result in ring 950 ballasted to remain below the surface buoy 900, while the main lower ring 960 rises to the surface and is kept substantially level by contact with the surface of the water body, thus ensuring good distribution of sunlight across the array when the array is substantially leveled through surface interaction.
As for the connecting lines 945, the number of support lines or wires 955 may be any plural positive integer (i.e., two or more). For example, although eight support lines or wires 955 are shown, the actual number of connecting lines 945 may be any positive integer by which 360 can be divided to give an integer or a regular fraction (e.g., 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 24, 30, 36 etc.). However, in many embodiments, the number of support lines or wires 955 exceeds the number of connecting lines 945 (e.g., by 2 or more times).
The intermediate lower ring 950 generally has diameter or width and length dimensions much smaller than those of the main lower ring 960. For example, the intermediate lower ring 950 may have a diameter (or a width and/or length) that is 5-20% of the corresponding dimension(s) of the main lower ring 960. However, the intermediate lower ring 950 may have a diameter, a width or a length greater than or less than that of the upper ring 910. Generally, the intermediate lower ring 950 can have a diameter, width or length from about 0.5 to about 2.0 times that of the upper ring 910. Thus, the apparatus 900 in
The apparatus 1000 comprises a frame or support 1010 on which the aquatic plants or macroalgae grow, first and second plow anchors 1020 and 1025 in the sea floor 1060, first and second buoys 1030 and 1035, and a platform 1100 that controls the depth of the frame or support 1010. The frame or support 1010 may comprise a plurality of sections 1012a-d, and is floating, submerged or partially submerged in the sea or ocean 1050. The first and second buoys 1030 and 1035 are respectively secured (e.g., tied) to the first and second plow anchors 1020 and 1025 by ropes or lines 1032 and 1037. The platform 1100 is secured (e.g., tied) to the first plow anchor 1020 by rope or line 1022. A tow rope 1015 is secured to the frame or support 1010 in at least two locations, and forms a loop around a motorized wheel or pulley 1150 and an underwater wheel or pulley 1040.
The platform 1100 comprises a floating base 1110, a solar panel 1120 or other renewable energy source thereon, a battery 1130 configured to store electricity generated by the solar panel 1120, and an electric motor 1140 that receives electrical power from the solar panel 1120 or battery 1130. The motor 1140 rotates the wheel or pulley 1150 in the clockwise and counterclockwise directions to raise and lower the frame or support 1010. The solar panel 1120, battery 1130 and motor 1140 (as well as any other electrical components on the platform 1100, such as sensors, broadcasting/signal receiving equipment, sonar-based detection equipment, etc.) can be powered and controlled by a control system and controller circuit similar or identical to the system 400 in
The platform 1100 may raise and lower the frame or support 1010 in accordance with the method 600 in
The buoys 1030 and 1035 indicate where the plow anchors 1020 and 1025 are, and thus, where the anchor line 1022 and tow line 1015 are, and where the frame or support 1010 is at night. This way, other watercraft and vessels can avoid inadvertently striking or contacting the lines 1015 and 1022 and the frame or support 1010 (and, by virtue of their proximity to the buoys 1030 and 1035, the lines 1032 and 1037). Thus, in some embodiments, the buoys 1030 and 1035 may not be more than a predetermined distance apart (e.g., 1000 m, 500 m, or any other distance at which other seacraft and water vessels can determine the relationship between the buoys 1030 and 1035). In other or further embodiments, the buoys may have the same color and/or pattern, and/or may be equipped with a light (for operation at night) having the same color, or emitting light in the same pattern.
The frame or support 1010′ generally comprises a frame made of a water-insoluble material with a density less than, equal to, or about the same as the density of the water it is in (e.g., sea water, which may have a density of about 1.03 kg/liter). For example, the frame may comprise wood, bamboo, an organic polymeric material, a combination thereof, etc. Each section 1012a-b may comprise a plurality of support rods 1013a-b joined or secured to the frame, which may be equally spaced apart along a width or length of the section 1012a-b, although the invention is not limited to these arrangements. The support rods 1013a-b also generally comprise wood, bamboo, an organic polymeric material, but they may be the same material as or a different material from the frame.
Adjacent support rods 1013a-b define a space 1018a-b for growing plants or macroalgae. In some embodiments, the plants or macroalgae are secured to the support rods 1013a-b directly. In alternative embodiments, the plants or macroalgae are secured to a mesh or net secured between the adjacent support rods 1013a-b, or are placed in a cylindrical mesh or net secured to the support rods 1013a-b and/or frame with a rope or wire that passes or is interweaved through the mesh or net (and optionally at least once around one or both of the adjacent support rods 1013a-b) and tied at each end to the frame. As the plants or macroalgae grow, parts of the plants or macroalgae may pass through the mesh or net, depending on the sizes of the plants or macroalgae and the openings in the mesh or net, and the parts of the plants or macroalgae that remain in the mesh or net can cause the mesh or net to expand in width or diameter. To accommodate this growth, the mesh or net (and the rope or wire securing it to the frame or support 1010′) may have a length greater than the length of the space 1018a-b (e.g., by 1.5-2 times or more).
The tow rope 1015 is secured to the frame or support 1010′ by passing it through eyelets or loops anchored in the frame or support 1010′, passing it through holes or openings in the frame or support 1010′ and knotting or clamping it inside the frame or support 1010′ so that the knot or clamp cannot pass through the hole or opening, etc. As shown, the tow rope 1015 also passes through eyelets, loops or rings 1017a-b at the ends of a secondary rope 1016 that is similarly secured to an opposite side of the frame or support 1010′ from the tow rope 1015, thereby distributing the load and stresses on the frame or support 1010′ when it is raised or lowered.
After the seaweed or aquatic plants are grown to a harvestable size, the seaweed or aquatic plants may be released (untied or otherwise unsecured) from the lower ring (or the mesh or frame thereon) and harvested with a seaweed harvesting apparatus as disclosed in U.S. Prov. Pat. Appl. No. 63/191,433, filed May 21, 2021 (Attorney Docket No. CF-005-PR) or in International Pat. Appl. No. PCT/US2022/______, entitled “Apparatuses, Devices and Methods for Harvesting Seaweed and Aquatic Flora from Large Bodies of Water for Storing and Transporting Seaweed and Aquatic Flora,” and filed contemporaneously with the present application. Optionally, the harvested seaweed or aquatic plants may be processed on a vessel, barge or platform (e.g., deploying the seaweed harvesting apparatus) and packaged (e.g., baled or bundled) as disclosed in U.S. Prov. Pat. Appl. No. 63/191,453, filed May 21, 2021 (Attorney Docket No. CF-006-PR) or in International Pat. Appl. No. PCT/US2022/______, entitled “Apparatuses, Devices and Methods for Harvesting Seaweed and Aquatic Flora from Large Bodies of Water for Storing and Transporting Seaweed and Aquatic Flora,” and filed contemporaneously with the present application. Thereafter, the packaged seaweed or aquatic plants may be towed to deep water (e.g., with a depth >1000 m) if necessary, and sunk in the relatively deep water as a form of carbon sequestration/carbon credits, as disclosed in U.S. Prov. Pat. Appl. No. 63/191,505, filed May 21, 2021 (Attorney Docket No. CF-016-PR) or in International Pat. Appl. No. PCT/US2022/______, claiming priority to U.S. Prov. Pat. Appl. No. 63/191,505 and filed contemporaneously with the present application.
In one example, the array 1100 is 100 m long×100 m wide. In this example, the bow pipe 1110 comprises two 0.6 m-diameter HDPE pipes with 3 mm walls, the stern pipe 1130 comprises a 0.15 m diameter HDPE pipe having a standard dimension ratio (SDR) of 41, and the ribs 1120 comprise 0.125 diameter HDPE pipes with 2 mm walls. The ribs 1120 and the stern pipe 1130 may be smooth-walled or corrugated. The array 1100 as shown in
The ribs and stern pipe 1120 and 1130 have hollow interiors and share a common volume, and are full of air during the day. It may be useful to pressurize them to a few atmospheres to stiffen the pipes, as long as this maximum pressure does not result in a need to increase the thickness of the pipe wall beyond 1-2 mm (a practical maximum wall thickness for high-yield extrusion manufacturing). The pipe array 1110-1130 is robust against waves and storms, and supports seaweed growing thereon in a manner that promotes a high growth rate, as well as easy seeding and harvesting. The ribs may comprise, for example, pipes, structural members, angles, brackets, and tensile structures such as ropes, tethers, tube nets and netting.
The support structure 1100 (e.g., the “raft”) moves to hold its shape. The arrow 1140 indicates a preferred direction of motion of the raft 1100. Raft movement may be implemented or caused using otter boards and a water-sail.
At night, the rib and stern pipes 1120 and 1130 are flooded (e.g., filled with water). By matching the buoyancy (e.g., density) of the support 1100 to the buoyancy of the seaweed or other aquatic flora thereon, the array 1100 should sink upon flooding the rib and stern pipes 1120 and 1130.
The stern pipe 1130 may be flooded first, and then the ribs 1120, from stern to bow, causing the raft 1100 to sink “stern down,” thereafter assuming a vertical or substantially vertical orientation, suspended by the bow pipe 1110 (which remains floating).
The top part 1155 of the tether is removable for seeding and harvesting (see
Stern and ribs 1120 and 1130 are hollow, welded or bolted together, and filled with either air or seawater. As HDPE has a density of 0.95 g/cc, they float in either case. They support the seaweed-filled tethers 1150, which may be weighted to remain submerged.
The tethers 1150 contain two parts. The bottoms and sides of the tether 1150 are fixed in place and held by horizontal tension cords, one of which is shown here. The top 1155 of the tether is removable and serviceable from a seeding/harvesting catamaran, which travels parallel to the long axis of the ribs 1120. Hoop nets may require some space between the hoops for seaweed penetrating the net material. Creating this space is easily accomplished.
Although seaweed sinks (density approximately 1.04 g/cm3), the tether, if made of HDPE as well, may require small weights (not shown) that keep the tether 1150 submerged below or relative to the surface. If giant kelp is being grown, the spacing and diameter of the ribs 1120 (from which the holdfasts hang) should be increased. Aquatic plants and other flora having a length of 20-25 meters or more should not get tangled as the array 1100 swings from horizontal to vertical. Tube nets are useful for retaining the seaweed, which alternatively may be grown directly on rope stringers as is common practice today or even on irrigation tubing.
The air-filled pipes 1120 and 1130 may be autonomously filled with water and sunk in a controlled manner. Flooding the pipes 1120 and 1130 may be as simple as opening a vent. The bow pipe 1110 is filled with air and sealed, so it always remains at the water surface. The bow end of every rib 1120 may have a small valve that, when opened, allows air to enter or leave. One end of the stern pipe 1130 may have a small electric pump to move water out of the stern-and-rib assembly, while the other end of the stern pipe 1130 has a back-flow-protected vent to allow water to flow into the ribs 1120. To sink the ribs 1120 such that the stern end 1130 sinks first, the stern pipe vent is opened, and the bow-end of all the ribs 1120 vent. The stern of the array starts to sink as water enters at the stern pipe 1130 and pushes air out of the bow-end of the ribs 1120 (which may be held by ropes). When the array 1100 is hanging vertically in the water, all vents are then closed. The weights that overcome the buoyancy of the HDPE ribs 1120 are not shown. They are part of the seaweed support and travel with the ribs 1120. When vertical, the stern of the raft 1100 is at a depth of about 100 m.
After the array is vertical, it may be further lowered by uncoiling ropes 1160 from the bow pipe 1110 that connect the bow pipe 1110 and ribs 1120, as shown in
The ropes 1160 may alternatively be uncoiled using an extra heavy weight and a torsion spring (to store the gravitational energy), and then the stored energy can be used to pull the ribs 1120 back up, like a simple roller shade on a window. In another alternative, an electric motor can be used to coil the ropes 1160 onto the bow pipe 1110. A third alternative is a counterbalance and winch, similar to an elevator.
It is not critical for lowering and raising operations to be fast. For example, if it takes an hour to flood the array, an hour to lower the array, an hour to evacuate the array, and an hour to raise the array, there is still about 10 hrs of daylight for growing and 10 hours of nighttime submersion for the plants or macroalgae to store nutrients.
After using a motor, a torsion-spring, or both (or another mechanism) to pull the ribs 1120 back up, the water-filled ribs 1120 and stern pipe 1130 may be inflated to reverse their motion and return to the horizontal position. In its final up position, the bow end of the ribs 1120 are out of the water.
The stern pipe vent is closed, the rib vents are opened, and the electric pump is turned on. For example, the stern pipe vent may be a one-way vent that allows fluid to enter, but not to escape. Each rib 1120 has a small valve that, when opened, allows air to enter or leave. Alternatively, the rib valves may be two separately-controlled one-way valves. Water is pumped out of the stern pipe (bottom), and air is drawn into the ribs 1120. The array 1100 starts to rise, with the stern pipe 1130 floating last, as it is the last to be emptied of water.
When the ribs 1120 are open at the top, the pump may be working against a head pressure. For example, when the ribs 1120 are 100 meters long, this head pressure can be as great as ˜10 atmospheres. In such cases, it may be better to push the water out of one or more of the ribs 1120. Unless the water is pushed out of a center rib, such a push may slightly shift or rotate the array 1100, but the head pressure would drop dramatically as the differences in water density are small. Care should also be taken to ensure that no pipes collapse due to external pressure.
In one example, the macroalgae to be grown on the support structure 1100 may be Kappaphycus, which is nearly the density of seawater (density≈1.04 g/cm3) when growing. Information about Kappaphycus is shown in
In some embodiments, inflatable spheres may be added to ends of the stern pipe 1130 to prevent collapse of the rib and stern pipes 1120 and 1130. For small rafts 1100 (e.g., having a surface area of about 500 m2 or less), such inflatable spheres may not provide such a beneficial effect. In other or further embodiments, a guard ring (e.g., ring 1240, as shown in
In some embodiments, the seeding and/or harvesting may be staggered (i.e., offset) in adjacent rows (e.g., along adjacent ribs 1120) to reduce both crowding and variation in the mass of seaweed. In other or further embodiments, ballast may be added to the tethers 1150. In even further embodiments, one or more spaces (e.g., between ribs 1120) may be formed in the raft 1100 for a seeding and/or harvesting catamaran to travel through the raft 1100. Such a catamaran may be modified to travel over the bow pipe 1110, the stern pipe 1130, and any cross-brace pipes.
In another example, red seaweed is known to have high biomass growth for about the first 32 days. The recommended time to harvest is 45 days. Thus, there are nearly 2 weeks when biomass increase is small. Carrageenan content continues to increase during this period. Consequently, in one embodiment, the start (e.g., timing) of seaweed planting is staggered in adjacent seaweed nets 1150. For example, when the planting of half of the rows (e.g., odd-numbered rows) is 32 days after the other half (e.g., even-numbered rows), then plants are just starting in one set of rows when the adjacent rows have slowed vegetative growth. This interleaving allows good sunlight penetration for young plants, and reduces the variation in the total raft tonnage. Planting in odd-numbered rows may be staggered from planting in even-numbered rows by 22.5 days (i.e., midway through the full growth cycle of red seaweed). Alternatively, two layers of plants may be grown, with plants on the bottom layer being 22.5 days older than plants on the top layer, but this arrangement may be challenging to seed, harvest, and keep submerged at an ideal level.
The more seaweed there is on the raft 1100, as its density is less than that of seawater, the more ballast may be added to the raft 1100 to keep the seaweed submerged. In one embodiment, a partially or fully inflated (air-filled) metal pipe in the bottom of each tether 1150 may be partially filled with sea water (e.g., each day) to offset the daily increase in plant growth. In alternative embodiments, a fixed amount of ballast is added or removed (e.g., to or from those tethers 1150 having a significant change in plant mass). The raft lift comes from inflating the pipes 1120 and 1130, so the lighter the raft 1100 is, the faster (or sooner) it rises. If a slow rise is desired to reduce thermal and/or pressure shock, the water evacuation (and/or its rate) from the pipes 1120 and 1130 should be controlled.
In yet another example shown in
The float segments 1182a-h may be sufficiently vertically displaceable to be lifted over the larger diameter bow pipe 1110 as well. In such embodiments, a series of seaweed rafts 1100 can be sequentially harvested, one after the other, until the last raft in the series is reached. Thereafter, the catamaran 1180 can move to the front of the next set of ribs 1120, and drift back again through the line of rafts, seeding and/or harvesting as it drifts. Of course, the catamaran 1180 can continuously move along the series of rafts 1100 and back, but likely takes more power than moving to the front, either by moving right up the set of adjacent ribs and up and over every bow and stern pipe 1110 and 1130, or just moving around the line of rafts.
Seeding and harvesting take place through a vertically displaceable (e.g., submersible) section 1186 of the catamaran deck (not shown). This vertically displaceable section 1186 can be raised and lowered. Alternatively, the section 1186 of the catamaran deck can simply open up for accessing the water surface, and if desired, another mechanism (e.g., ladders, small platforms, or simple cable, rope or chains) that can be lowered from the deck, but that provides a relatively secure hold or surface from which one can access the surface tether(s) 1155 and other parts of the raft 1100, can be used.
For a hectare-sized square raft 1100, 100 meters of head (water pressure) must be pumped (e.g., into the stern and ribs 1120 and 1130) when vertical. Thus, an HDPE stern pipe 1130 should have an inner diameter of 150 mm, and preferably SDR 41 (e.g., 3.8 mm wall), so that the pipe 1130 does not collapse when evacuated and still vertical.
On the other hand, the ribs 1120 can be half the diameter of the stern pipe 1130 and have a relatively thin wall (e.g., 2 mm). Ideally, the ribs 1120 can be directly welded into bored holes in the stern pipe 1130.
When the stern and ribs 1120 and 1130 have such dimensions, the total volume of water to be removed is ˜28 m3. The water can be removed in 60 minutes at full head with a 20 HP, 3-phase, 6-stage submersible pump at 71% efficiency. As the raft 1100 starts to become horizontal, the power requirements for the pump drop, and the pump output flow rises. A 15 HP, single phase pump at 76% efficiency may be effective when the raft 1100 becomes substantially horizontal. Ideally, the pump is a direct current (DC) pump.
A 15 HP pump may use 11.2 kW of power at peak, which may consume more power than some relatively affordable portable, green power solutions (e.g., a solar panel for remote use). Increasing the pumping time to 2 hours reduces the flow to 12 m3/hr., allowing use of a 7.5 HP, 8-stage, single-phase pump.
As the stern pipe 1130 is emptied, the raft 1100 starts to move to a horizontal position (e.g., for absorption of sunlight by the aquatic flora). A 5 HP pump can provide 100 m of lift at 20% of the target average flow, but the flow rises to the desired 12 m3/hr. at roughly 60 meters of head. Under such conditions, a 4-stage, 5 HP pump can be used, even though it may work at only 40% efficiency. The 5 HP pump has larger power requirements than a winch, making an arrangement and/or geometry in which water is pushed out of one or more ribs 1120 attractive, reducing the head pressure.
It is beneficial for the ropes 1160 (
From the chart in
When the maximum weight to lift is ˜3.0 metric tonnes, the ropes must have a minimum static operating strength of 50 kg per line times the dynamic loading factor of 2-8× for dynamic loads under open-ocean conditions for a raft 1100 including 60 ropes 1160. It is important to note that the service operating strength is less than the minimum breaking strength. If the raft 1100 is to be lifted 700 meters in 60 minutes, then the ropes 1160 must be pulled in at a rate of 12 meters/minute. A single drive motor can wind 30 lines onto a rotating set of drums (e.g., supported by the bow pipe 1110), and concurrently wind the other 30 lines on a counter-rotating set of drums. The winch may have a size suitable for the target uptake (pull-in) speed and total load. The drums and gearbox may be customized for a particular application.
A 7.5 HP winch can lift about 2.7 metric tons with a 5× safety factor at 12.2 m/s. Such a winch weighs 431 kg with a single spool. When lifting a maximum load of ˜2.0 metric tonnes over the course of two hours, then a 3 HP, single-phase motor can be used for the winch, which cuts the maximum power requirement to 2.2 KW, and reduces the weight to 239 lbs. Such a winch motor benefits from the further inclusion of the torsion spring described herein to lift the raft 1100. On the other hand, a winch with a stronger 5 HP motor, such as that shown in
In embodiments in which the winch drums are not integrated onto the bow pipe 1110, it is possible to support the winch and drums between two bow pipes 1110, as shown in
For an array 1100 having an area of one hectare, the dimensions of the pipes can be optimized. For example, the inner diameter of the double-bow pipe 1110a-b may be determined by (e.g., may match or exceed) the height of the winch 1195. Thus, in our example, each bow pipe 1110a-b may have an inner diameter of 0.6 meter. To keep the mass of the bow pipes 1110a-b low, but allow some overpressure, the walls may have a thickness of 3 mm.
The inner diameter of the stern pipe 1130 may be set by the size (e.g., power, in HP) of the pump that removes water from it. In our example, the inner diameter of the stern pipe 1130 may be 0.15 meter. The stern pipe wall may be determined by the pressure of the seawater on the pipe 1130 when it is empty. When the pressure is that of 100 meters of water, the stern pipe wall may have a thickness of 3.8 mm (at a standard dimension ratio [SDR]=41).
The inner diameter of the ribs 1120 (e.g., when they comprise pipes) may be 50% or less of the diameter of the stern pipe 1130, if the rib pipes 1120 are directly welded to the stern pipe 1130. For example, the inner diameter of the rib pipes 1120 may be 0.075 meter. The rib pipe wall can be a minimum of 2 mm, to withstand the pressure of 100 meters of seawater without collapse. In some embodiments, both the rib pipes 1120 and the stern pipe 1130 can be inflated to 3 bars pressure.
The total tonnage of HDPE pipes having such dimensions in a one-hectare array 1100 is ˜408 tonnes per sq. km. Drag and lift forces on the array during lifting are not expected to be significant, although the addition of one or more hydro-foils to the array may reduce such forces. When the pipes have a relatively small diameter, the hydro-foil(s) may be relatively simple, or omitted altogether.
In embodiments to increase robustness of the array 1100, a water-filled guard-ring (e.g., ring 1240 in
To provide power to the motors for the winch 1195 and the water pump (e.g., 3 HP and 5 HP, respectively, as power source should be provided, preferably one that provides renewable or “green” power. Given that one HP is 0.746 kW, peak power for a 5 HP motor is ˜3.7 kW, and for a 3 HP motor is ˜2.2 KW (see
The present system may require power at night (e.g., to raise the plants to the surface before or at daybreak), but during the plant growth season, often less than the maximum tonnage is being lifted, and the power of the pump throughout the vertical-horizontal transition of the raft 1100 is likely less than its maximum. However, the calculations in
Some results of the system employing the raft 1100 are surprising. For example, because there is no expensive “lift pipe,” large rafts are not favored. The manner in which the rafts are raised and lowered, and the manner in which the buoyancy of the raft is changed, favor small arrays. However, an array 1100 having an area of one hectare is plausible, although an optimal size for the raft 1100 may be different, especially when using different materials, growing different aquatic flora, and/or implanting a different design/architecture. Furthermore, the technology to raise and lower a raft 1100 are essentially available today, with at most minor modification.
There may be an advantage to propelling the raft 1100 unmoored. Jet propulsion, for example, may enable navigation of certain arrays 1100, by simply directing rib perforations in a certain manner. Alternatively, a bow-mounted, conventional, single hydro-jet solar-powered engine with a rudder may propel the raft 1100, but its efficiency may be relatively low due to the relatively slow speed obtainable using such an engine. A specialized propeller (see, e.g.,
In such a case, the bow area of a raft/array 1200 may be designed to accommodate a solar array 1210 and engine, as shown in
Ideally, the raft 1200 may be designed with an aspect ratio (i.e., ratio of the length to the width) to reduce drag and reduce stresses on the bow, ropes and take-up reels (e.g., winch drums), etc. Thus, the ribs 1220 may be longer and fewer in number, and the stern pipe 1230 may be shorter. The arrow 1250 indices the direction of propulsion.
In the raft 1200, water may be driven and/or evacuated from the rib and stern pipes 1220 and 1230 through a rib tube 1220, as it is generally not advantageous to increase the head pressure during a lifting operation. Associated frictional drag may also be analyzed. The plants or seaweed may also benefit from greater variation in nutrients, temperature, etc. during night-time feeding.
An exemplary propeller is shown in
An analysis of the chart in
Although an electrical generator and battery can be added to the raft, it may be simpler and more energy-efficient to mechanically store the energy from lowering the raft, and use the mechanically-stored energy to raise the raft in the morning. A spring built into the interior of a winch drum may provide the mechanism to mechanically store such energy.
The spring is ideally of a constant, but selectable, force. For example, a plurality of spring in parallel may be present, and as many as are needed in a given situation can be engaged. The table below includes parameters for a torsion spring design suitable for replacing the 3HP motor in the winch for the hectare-sized example array.
indicates data missing or illegible when filed
The purpose of the bias float 295 is discussed with regard to
In the top view, the vertical scale has been highly exaggerated to show the pre-tensioning cable 310. In the side or cut view through solar panel 230 in
We now discuss how the seaweed frame is rotated from horizontal as shown in
Water enters through stern valve 494, displacing the air which leaves the rib valves 474. Referring to
The system may be implemented without the need for human oversight. A convenient means to determine when the rotation is complete is that the proper length of bias float rope 596 has been pulled from its winder. However, for various reasons, the sensor may fail to indicate that the rotation is complete. As a backup, if valves 474 and 494 require energy to remain open, then a timer may be employed to close them after sufficient time has elapsed to flood the raft.
Rope-winders may be engaged to lower the ropes to the prescribed depth. For a 50-meter rib pipe, and the algae Kappaphycus, one can lower the seaweed approximately 100 meters by unwinding 100 meters of rope from all reels. Again, the lowering may be done slowly, over about 30 minutes, to not thermally shock the seaweed. There, it stays until just before sunrise, whence the multi-reel rope-winder is employed again to slowly raise the seaweed. Suspension ropes 435, as well as bias float rope 496, may be lowered and raised synchronously, using their associated rope winders.
The gravitational potential energy to raise the seaweed array depends on the total weight to be raised, plus any energy losses due to friction, electrical resistance, or drag. Ballast may be arranged, for example, such that the total mass to be raised is 250 kg. The force of 250*9.8=2450 Newtons can be compared with the force exerted by the seaweed as it is raised. The seaweed may be modelled as a rectangular cross-section 50 meters wide by 0.2 meters high, with a drag coefficient of 0.2. If the rope-winder is allowed 17 minutes to pull up 100 meters or rope (or 120 minutes to pull up 700 meters of rope), then the drag force
is easily computed as 19 Newtons, or less than 1% of the gravitational force. Thus, the drag force can, in effect, be ignored.
After the suspension ropes have been reeled in so that the rib valves 474 are above the ocean surface, the seaweed array can be rotated from vertical to horizontal, reversing the original motion. This rotation may be accomplished by forcing air in at high pressure, driving the water out. However, water ejected from the stern pipe while the seaweed array is vertical is at roughly 5 bar, corresponding to a water depth of 50 meters, requiring considerable air pressure. Alternatively, water may be forced out at 5 atmospheres, letting air in at atmospheric pressure to the shared interior of the rib-stern pipe array, restoring its buoyancy. The figure shows the latter method. The pumping may be accomplished by action of a submersible pump, which pumps the water out of the shared interior of the rib-stern pipe assembly.
As shown in
As the water is ejected, air fills the rib-stern piping from the bow end. The stern pipe will be filled with air last. This staged filling of the array keeps the seaweed array in plane, reducing stress on the piping. Once the seaweed array is horizontal and floating at the surface, which preferably happens at dawn, the nutrients that were stored in the seaweed vacuoles can now be processed via photosynthesis into plant tissue.
An example of such a pump is a 100 mm (4 inch) commander S series submersible water pump, available from Flint and Wallings Corporation. Their models 4F19A15, 4F19S15, and 4F19G15, 1.5 horsepower, 12 stage, stainless steel pump can move at least 12.7 gallons per minute (48 liters per minute) at a discharge pressure of 80 psi, from a depth of 180 feet (55 meters). At this pump rate, the water contained within the interior of the seaweed frame 245 may be ejected in 70 minutes. As the frame reverses its initial rotation, however, the pump returns to the ocean surface, and the water ejection speed rapidly rises to a maximum of 25 gallons per minute, potentially resulting in a smaller size pump, reducing pump cost and pump power. The 1 HP version of this pump has just 9 stages and can move 13.7 gallons per minute at 20 psi from a depth of 180 feet, achieving the same maximum pump rate of 25 gallon per minute at 80 feet.
The sinking of the seaweed raft need not only occur at night. Ocean storms rarely disturb water at a depth of 50 meters. Hence, submerging the array is a convenient way to avoid conditions that otherwise may damage the array at the surface. Thus, the bow area 210 in
The seeding and harvesting of Kappaphycus seaweed grown in the covered hoop-nets 540 in
The nets of
The vessel should also have an access port to the netted seaweed, i.e., an opening in the deck, illustrated by a moveable platform 1186, which when lowered allows access to the netted seaweed, so that the nets may be opened and closed to harvest the seaweed and reseed the nets for the next growing season. Parts of the structure that may potentially collide with an obstacle 1130 can be raised, as illustrated in
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims of any subsequent nonprovisional application that claims priority to the present application and their equivalents.
This application claims the benefit of U.S. Provisional Patent Application No. 63/191,798, filed on May 21, 2021, and incorporated herein by reference as if fully set forth herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US22/30404 | 5/20/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63191798 | May 2021 | US |
