RENEWABLE ENERGY WAVE GEAR DRIVE - WGD SYSTEM

WAVE GEAR DRIVE -WGD SYSTEM

I. Wave Gear Drive -WGD - NEW

1.    The Wave Gear Drive, WGD System is a new method for directly converting sea wave energy to mechanical drive using wave undulations and a buoyant float directly acting on a spiral spring or rack and pinion and VSG gear, to drive a positive displacement, rotary or centrifugal water pump that pumps a small quantity of water to a high head, collect it and feed it to an offshore hydro turbo generator to generate electric power and transmit it to the shore using power and control cables laid at the sea bed; or;

2.     To drive a Variable Speed Input/Constant Speed Output (VSG) gear directly coupled to a 3-phase electric generator whose output runs in parallel with other A.C. generators, and is transmitted to shore using power and control cables laid at the sea bed, or,.

3.      Convert the A.C. output in D.C., and run the generators in parallel.

4.      Ideal for use on offshore oil platforms to generate electric power using direct drive generators or water pumps, or using water pumps to generate electric power and to pump cold water from 1-meter above sea bed and use the water temperature difference between surface and deep water for air conditioning (SWAC), or to generate additional electric power. In this case suction inlet is at 1-meter above the sea bed and suction lines are fixed to the mooring cables.

5.   Pumps or Generators are installed 5-meters below Mean Sea Level.  Equipment are installed with quick coupling and decoupling means for ease of installation and maintenance.

 6.  Output of System: Systems should provide loads as needed.  The proposed systems operate as a single unit to provide electrical outputs for waves ranging from 1.5 to 8 meters:

a.       For 1-WGD ranging from 3.23 to 96.48 kw per 90 degrees.

b.      For a set of 10 units installed in line with the incoming wave provides an output ranging from 0.84 to 147.46 kw per one wave pass of 360 degrees.

c.       Installing 10 sets, 10 units each in an area not exceeding 15 by 30 meters would provide an average output ranging from 8.4 kw to 1,474.6 KW (1.4746 MW).

d.   Installing 100 sets of 10 units each can generate average electric power at the rate up to 15 MW using an area measuring 30x182 meters.

BRIEF SUMMARY OF THE WGD SYSTEM

The WGD is a method for extracting sea wave energy using wave undulations and a buoyant float to directly act on spiral spring or a rack and pinion to drive:

a.   A water pump that pumps a small quantity of water to a high head, collect it and feed it to an offshore hydro turbo generator to generate electric power and transmit it to the shore using power and control cables laid at the sea bed, or

b.  A generator to generate alternating current electric power, convert it to direct current, operate in parallel and transmit the direct current to the shore using power and control cables laid at the sea bed where it is controlled, conditioned and distributed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG.-1 WGD System Layout and Cover Sheet.  It a schematic diagram for the whole system with identification of parts.

FIG. 2 WGD Gear Drive Details.

It includes equipment and its identification of parts.

FIG. 3 WGD Generator System. It includes plan, elevation and identification of parts.

FIG. 4 WGD HTG. System Layout.  It includes the Hydro Turbo Generator and identification of parts.

FIG. 5 WGD Mooring Details. It includes the mooring system and identification of parts.

FIG 6 WGD Water Flow Piping.  It includes water flow layout, piping and identification of parts.

FIG 7 WGD Power & Control Cables.  It includes layout of power and control cables and identification of parts.

FIG 8 WGD Block Layout and Power Output.  It includes a block layout of assembled system with power and control cables and identification of parts.

LISTING OF TABLES

 Table 1    WGD System performance, for Wave Heights of 1.5 to 8 meters, for 1-Pump or Generator, and for sets of 10 Pumps or Generators. For Peak, and Average for 207 & 360 Degrees

DETAILED DESCRIPTION OF THE WGD SYSTEM

     a.       GENERAL-Pumps and Generators

Dimensions of the individual WGD elements depend upon site, sea state and load requirements.

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.

b.      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 costs per kwh.

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 and providing shore line protection without interfering with marine life or scenic view. 

c.       OPERATION-WGD System

1.      As the wave front reaches its trough, the float falls down to its lowest level.  When the wave instantaneous level starts to rise, it will start to immerse the float until a sufficient buoyant upward lift is developed to overcome the weight of the float and of the rack or spiral spring restraining force.  Then the float starts to rise upward, until its top reaches the wave crest as maximum travel, in the mean time transmitting this motion to the pump as rotation at high rpm.

2.      A float with 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.

3.      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.

4.      The power generated is shown in table-1 above for different wave heights.

5.      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.

6.      A set of up to ten pumps or generators are installed in line with the incoming wave to extract most of its energy. Each pump or generators is fixed to the mooring structure by means of quick coupling to allow for horizontal swings and for ease of maintenance.

7.      A group of 100 pumps or generators fixed to the mooring structure constitutes a construction unit.  Additional construction units of 100 pumps or generators are installed to provide the required power output.

d.      OPERATION-Float and Gear Drive

1.      A float 150 cm OD and 150 cm high develops an uplift of 2,650 kg.  The float is cylindrical, red color with red flashing lights for safety of navigation, and is provided with means for connection to the gear rack or spiral spring.

2.      Top of gear drives and pumps are installed at a level of 6.00 meters below mean sea level.

3.      Gear Rack is 900 cm long and follows the motion of the Float.  It has travel limit stops to limit the up and down motion.

4.      Spiral spring can extend 900 cm, has a restoring force of 50 kg and can withstand a pull of 2,650 kg.

5.      Tip of the gear rack has a maximum downward travel of 15 meters below mean sea level.

6.      Gear drive transmits rotation to the pumps or generators only in the upward direction.  It does not transmit rotation in the opposite direction to the rack. Latching is in upward travel of the gear rack and releases at the downward travel.

7.      Gear Drive is coupled to the pumps or generators by a hermetically sealed universal joint.

8.      Gear drive is designed to develop per meter of float upward travel, one revolution t the gear input shaft to produce an output rotation of 30.  A 4-meter high wave has an average instantaneous travel of 1-meter per second which translates to 1,800 rpm to the pumps or generators.

e.       MOORING Pumps and Generators

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.

3.      Anchor is a set of beams of sufficient weight resting at the sea bed to hold down the mooring structure..

f.       WGD Pumps

1.      P1- P10 Pumps are rotary or centrifugal, connected to the reduction gear output by a universal joint.  They rotate at 1,800 rpm and deliver a small quantity of water at a high head depending on wave amplitudes.

2.      Shut-off and check valves control the pump operation and output.

3.      D1- is a discharge pipe that collects the pumps discharge for each set of 10 pumps.

4.      D2- is a common discharge pipe that collects the discharge of pipes D1.

5.      D3- is a main discharge pipe collecting the discharge of common pipes D2.

6.      D4- is a main header collecting the discharge of main discharge pipes D3 and discharges into the main header of the hydro turbo generator.

7.      The hydro turbo generator is installed offshore at 5,000 meters or more as required.

8.      Hydro turbo generator is mounted above water level on a fixed supporting structure is fixed and anchored to the sea bed.

9.      Power and control panel are fixed to the wall of the hydro turbo generator housing for protection and control of electrical equipment.

10.  L5- is a set power and control cables that are run at the sea bed and connect to the electric control panel at the shore

g.       WGD - Generators

1.      It is necessary to connect the outputs of the generators in parallel.  Due to the difficulty of synchronizing their alternating current outputs, the AC generator outputs are converted to D.C. and connected in parallel.

2.      G1- G10 are poly-phase generators directly coupled to the gear drive through a universal joint, rotating at 1,800 rpm to generate alternating current.  The AC current is converted to direct current by means of thyristor/diode circuits.

3.      The magnetic field circuit of the generator consists of a series connected coil and a shunt coil to achieve a compound wound generator with a flat output voltage in spite of current output variations.

4.      An additional and separate shunt coil is added to provide an additional magnetic field to boost the generator output voltage and allow the respective generator to be connected in parallel with the main D.C. bus of generators in a 10-G set.  This is achieved by:

a)     Connection to the main generator D.C. bus through a control circuit to boost each of the generator A.C. output voltage and    allow it to be connected in parallel with the main D.C. output.

b)     By Varying the number of turns of the shunt coil, by means of a control circuit, to increase the magnetic field strength, raise the  A.C. output voltage, consequently the D.C. voltage and allow it to be connected in parallel with the main D.C. output bus.

5.      The D.C. outputs of each set of ten generators are connected in parallel, are also connected in parallel to the adjacent 10-sets to form a unit of 100 generators, all connected in parallel and current transmitted to the electrical equipment at the shore, ready for distribution and/or connection to the local electric network.

6.      B1- are power and control boxes as part of the generator and contain the thyristors and control circuits to convert the generated alternating current to direct current, and to control the additional shunt winding.

7.      L1- are power and control cables that interconnect each set of ten generators.

8.      L2- are power and control cables that interconnect each set of hundred generators, and feed the power and control signals to the shore where it is controlled, conditioned and fed to the network for distribution.

Detailed Drawings available upon request

Pricing

Kindly Refer to Feasibility.

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Last modified: 07/27/10