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WAVE GEAR DRIVE -WGD SYSTEM 1. WGD-Description The WGD system consists of a buoyant float on the sea surface moving up and down with the wave motion developing an uplift force of 2,650.7 Kilograms. This uplift force is transferred through a rack and pinion or a set of pulleys and reduction gear to pumps or generators to generate electric power. The electric power is then conditioned, synchronized, fed to a step-up transformer and transmitted to the shore ready for connection to the electric network. ic The system converts wave energy using three means as follows:.
The WGD solves the scarce usable land at the shoreline by providing an offshore system with maximum space utilization and minimum foot print. This is achieved by: i. Adding the WGD system where offshore wind turbines are installed, thus practically using the same surface area. ii. Adding Reversible Ebb/Tide turbines to the WGD structure, at practically no additional cost or surface area and increasing the power output from the same surface area. A water/air reservoir is provided on top of the offshore structure to store wave energy and release it during a ten (10) second period to provide leveled power during the whole 360 degree cycle of the wave. Additional high inertia fly wheels, capacitors or other means are provided as needed to increase energy storage and wave output power leveling. The WGD is an offshore installation executed in structurally independent "Construction Units" individually moored and housing all energy extraction equipment, power conversion, control, voltage synchronization and step up transformers all installed on a dry dock. 2. WGD-Novelties There are seven novelties in the proposed WGD system. 1. The First novelty is simple, easy, light construction and construction costs using simple engineering principles, leading to competitive cost per KW-Hour. 2. The second novelty is a minimal system foot print of 0.00273 compared to 0.5 to 1.5 square km for 5 MW output. 3. The third novelty is transferring the float buoyant uplift directly into mechanical form to drive a pump or a generator. 4. The fourth novelty is in the way generators produce electric power, operate in parallel and transmit power to shore. That is generating alternating current, converting it to direct current, control output voltage and operate generators in parallel. 5. The fifth novelty is that the system auto adjusts to varying wave heights and varying sea levels. 6. The sixth novelty is in the mooring structure that occupies minimum space, resists storms and is safe to navigation. 7. The seventh novelty is a Free Floating Break Water Structure, leading to calm seas behind the system providing shore line protection without interfering with marine life or scenic view. 3. WGD Construction The WGD is executed in modular "Construction Units" each measuring 21 by 15 meters. These "Construction Units" are structurally independent and are independently moored to the sea bed to reduce costs and resist severe storms. The outputs of these "Construction Units" are interconnected so that the system behaves as one unit, Two types of WGD offshore systems with energy storage facilities are used: i. Floating underwater floating structure with a fixed structure to house the turbo generator, power and voltage control equipment and step up transformer. In this case pumps and generators are installed five (5) meters below mean sea water level. Equipment are installed with quick coupling and decoupling means for ease of installation and maintenance. ii. Fixed overwater structure with all equipment installed on a dry deck. Each “Construction Unit” has a footprint of 21x15 meters and consists of ten (10) sets with each set consisting of four (4) pumps or generators to give a total of forty (40) pumps or generators. As much as forty (40) “Construction Unit” can be installed in an area measuring 1,000x21 meters. Up to six (6) Ebb/Tide reversible turbo generators can be installed and fixed to each “Construction Unit”. All equipment, gear drive, universal joint, pumps and generators are hermetically sealed and suitable for marine installation. All pipes are flanged for ease of underwater construction. Power and control cable connections are of the quick coupling type. Dimensions of the individual WGD elements depend upon site, sea state and load requirements. 4. WGD Operation Wave Water Pumps are designed to lift a small quantity of water up to a working head of fifty (50) meters; the pumped water is collected and fed to a hydro turbo generator to generate electric power. A partially filled hermetically sealed water reservoir stores water and compresses the air on top of the reservoir water level. Stored energy is released to maintain power output during the lee side of the wave. Thus constant power is maintained during the whole wave cycle of 360 degrees. Required energy storage is for duration of ten (10) seconds. A float having an outside diameter of 150 cm and a height if 150 cm develops a total uplift force of 2,650 kilograms. Dimensions of the float depend upon sea state and load requirements. a. An upward travel of the spiral spring or of the rack of one meter/second is converted to one rotation/second at the gear input; and 30 revolutions per second at the gear output. This is equivalent to 1,800 rpm at the pump or generator. b. The power generated is shown in table-1 above for different wave heights. c. As the water of the wave is accelerating upward, it meets at the surface an area reduction due to the presence of the floats. This area reduction is estimated at 80% leads to wave height increase of 24% and resulting in increased power extraction. 5. WGD Mooring 1. Mooring is achieved by a submerged structure consisting of a set of hollow pipes or similar means to keep the spiral spring, gear, gear drives, generators, pumps and discharge pipes afloat with a net upward lift of 200 kg to minimize horizontal swings due to ebb/tide and sea currents. 2. Each mooring structure of 100 pumps or generators is tied by means of flexible lines to an anchor resting at the seabed. Flexible lines are spaced 3 meters apart to allow free movement of sharks and whales, if any. Anchor is a set of beams of sufficient weight resting at the sea bed to hold down the mooring structure.. 6. WGD Output The WGD system extracts energy from waves as low as 0.75 meters up to 8 meters, with equivalent power generation per "Construction Unit" ranging from 0.17 to 111.11 KW as shown in the table below. This power output is guaranteed. The figures shown in the table should be multiplied by 1.24 due to wave attenuation. That is as the water is accelerating upwards it meets a restricted surface area which acts to increase the wave height. Therefore, the REWGD system extracts energy from waves as low as 1-meter high.
Table 1 WGD System performance, for Wave Heights of 0.75 to 8 meters, for a set of 4 Pumps or Generators.
Detailed Drawings available upon request
PricingKindly Refer to Feasibility.
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