Patent Application
20130118176
This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2011 118 263.6, filed on Nov. 11, 2011 in Germany, the disclosure of which is incorporated herein by reference in its entirety.
The disclosure relates to a regenerative offshore energy plant according to the description below.
In the publication “A rotating wing for the generation of energy from waves” by Pinkster et al., published in 2007, a concept is disclosed for a wave energy plant that is used to convert the energy of wave motion. In it, a circulating orbital flow described by water particles in or under the wave is used to flow onto a lifting foil. The lift force of the foil circulating with the orbital flow is converted into rotation of a rotor shaft.
DE 10 2009 035 928 A1 likewise discloses a wave energy plant that is used to convert the energy of a circulating orbital flow. Here a resistance element is carried along by the orbital flow and sets a rotor shaft in rotation.
A disadvantage of such offshore energy plants is the technical complexity of the equipment, for example for anchors on the sea bed or floats and stabilizers and the relatively low energy yield in comparison with the technical complexity of the equipment, in particular when there is a moderate swell.
The object of the disclosure is moreover to provide an offshore energy plant that has an improved energy yield in comparison with the technical complexity of the equipment.
This object is achieved by an offshore energy plant having the features described below.
The offshore energy plant according to the disclosure has at least one wave energy plant for converting energy of a circulating orbital flow of wave motion, wherein the energy can be converted at least partially into rotational energy of a rotor rotating about in each case an associated axis of rotation (wave harrow). The energy plant here also has at least one wind turbine. An energy plant is thus provided in which synergies can be exploited by combining two plants that are separately constructed and erected in accordance with the prior art. There is, for example, just one anchor at one location on the sea bed or just one floatation device for the energy plant. The energy or power conversion can also be centralized. The energy yield is thus improved in comparison with the technical complexity of the equipment of the energy plant. When there is variation in when the wind and waves occur, it is possible to equalize the energy conversion with the energy plant according to the disclosure.
Other advantageous embodiments of the disclosure are described below.
A particularly preferred development has at least one generator for converting the energy of the rotor of the wave energy plant and/or of the at least one wind turbine. When just one generator is provided for the whole energy plant, the technical complexity of its equipment is reduced. A gearbox—in particular a summation gearbox—can be connected upstream of the generator or generators. A respective output shaft of the wind turbine can, depending on wind sensors, be coupled to the generator—in particular via a clutch. Alternatively or additionally, the at least one rotor of the wave energy plant can, depending on wind sensors, be coupled to the generator—in particular via a clutch. When a gearbox is provided, the coupling to the generator is effected indirectly via the gearbox.
Configurations of the at least one wave energy plant with and without a rotor shaft are conceivable. In the latter case, coupling bodies of the rotors can be coupled directly to the generator via lever arms. Coupling bodies can be resistance elements and/or buoyancy elements.
The energy plant can be configured so that it floats and can have a mooring (with cables or chains) or it can be anchored to the sea bed, in particular via pylons.
In order to keep the center of gravity of the energy plant as low as possible, it is preferred if the generator—or in particular the wind turbine generator in the case of different generators—is arranged in the vicinity of the still-water line (SWL). In the case of separate generators, in particular the wave energy plant generator is here submerged below the SWL and particularly preferably can be arranged coaxially with the axis of the rotor.
A first alternative of the wind turbine takes the form of a horizontal-axis wind turbine (HAWT) in which the abovementioned output shaft is arranged approximately horizontally. The wind turbine can here have another approximately vertical output shaft that is coupled to the horizontal output shaft via a deflection gear unit—in particular two bevel gears. Such a vertical output shaft enables the torque that occurs to be directed to a generator used together with the wave energy plant. A very efficient development is thereby provided.
It is preferred here if the wind turbine can track the direction of the wind. The efficiency of the wind turbine can thus be maximized in the case of different wind directions.
A second alternative of the wind turbine takes the form of a vertical-axis wind turbine (VAWT) in which the output shaft is arranged approximately vertically. These do not require any deflection or angling of the output shaft and no tracking.
The at least one VAWT can here have a Savonius rotor and/or a Darrieus rotor and/or a Voith Schneider rotor and/or a Gorlov turbine and/or a C rotor and/or a Lenz rotor and/or a Tesla turbine.
The wave energy plant can preferably track the direction in which the waves propagate. The efficiency of the wave energy plant can thus be maximized in the case of different wave directions.
At least one coupling body circulating about the axis of the rotor with the orbital flow is coupled to the rotor of the wave energy plant or plants. It can be at least one resistance element and/or at least one buoyancy element. They can be arranged in such a way that the torque acting on the rotor is maximized. A combination of two buoyancy elements is in particular preferred here. Moreover, the angle of attack of the buoyancy elements can be set depending on the local flow onto the buoyancy elements. Moreover, the rotational speed of the rotor can be set in particular by adapting the generator torque taken off. It has been observed here to be particularly advantageous if a largely constant phase displacement is set between the rotation of the rotor and the orbital flow.
Different exemplary embodiments of the disclosure are described below with the aid of the drawings, in which:
a and lb show a first exemplary embodiment of an offshore energy plant according to the disclosure in two different states;
a and 1b show a first exemplary embodiment of an offshore energy plant according to the disclosure in two different states. Below the wavy water surface 1 of an expanse of sea, the energy plant has a wave energy plant 2, and above the water surface 1 it has a wind turbine 4. The energy plant is configured to float and is anchored to the sea bed 8 via a mooring in the form of a chain 6.
A direction in which the waves propagate 10 and a wave direction 12 (from left to right in
The energy plant has a casing 18 that is held suspended between the water surface 1 and the sea bed 8 by a buoyancy device (not shown). Moreover, the energy plant can be stabilized in the water via damping plates (not shown).
A side view of the wave energy plant 2 is shown in
The wind turbine 4 is arranged on a top side of the casing 18 and essentially consists of an output shaft 22 that is oriented largely perpendicularly and to the upper part projecting from the water of which at least two curved profiles 24a, 24b are fastened in such a way that they form a Darrieus rotor. According to a first exemplary embodiment, the wind turbine 4 thus forms a vertical-axis wind turbine VAWT that feeds additional rotational energy into the energy plant via its output shaft 22 independently of the wind direction 12.
The rotational energy that occurs simultaneously or with a time delay at the wind turbine 4, on the one hand, and at the two rotors 20a, 20b of the wave energy plant 2, on the other hand, drive at least one generator (not shown) that is arranged in the casing 18 and the electrical energy of which is transmitted to the shore via an electric cable (also not shown). According to the disclosure, it may also be provided that the two buoyancy rotors 20a, 20b shown are securely coupled such that an alternative with a one-piece rotor results in principle.
Clutches can preferably be provided in order to decouple the wind turbine and/or wave energy plant from the at least one generator, should the energy input be correspondingly low.
A water surface 101, the average height of which is defined by the still-water line 101 between a wave crest (cf.
The wind turbine 104 is configured as a horizontal-axis wind turbine (HAWT). It can have an output shaft 123 accommodated in the approximately perpendicular mast. An approximately horizontally oriented output shaft 122 is provided at the top end portion of the mast and of the output shaft 123. A wind wheel that preferably consists of three rotor blades 124a, 124b, 124c is arranged on the horizontally oriented output shaft 122. The horizontal output shaft 122 can here be coupled to a generator (not shown) via a set of bevel gears (not shown) and via the output shaft 123. As explained with reference to the first exemplary embodiment, the two resistance rotors 120a, 120b of the wave energy plant 2 are likewise coupled to the generator.
Inside it, the frame 428 carries four rotors 420a, 420b, 420c, 420d that form the essential components of a wave energy plant 402. The frame 428 is oriented with respect to the direction in which the waves propagate 10 in such a way that two longer portions of the frame 428 are oriented essentially in the direction in which the waves propagate 10 and the rotors 420a-d are oriented essentially transversely thereto. The orbital flow that results from the wave motion thus flows onto the four rotors 420a-d and the latter are set in rotation such that a torque acts about the rotor axes. This torque can be converted into electricity at each of the four rotors 420a-d via an individual generator (not shown), but it is also possible to bring the torques together in a common generator by individual means. A wind turbine 4, that in the first exemplary embodiment is configured as a Darrieus rotor that is not dependent on the wind direction, extends in each case upwards from the two longer portions of the frame 428.
An offshore energy plant is disclosed that has a wave energy plant for converting energy of a circulating orbital flow of a swell into mechanical energy of at least one rotor, for example using the wave harrow principle. The energy plant here also has at least one wind turbine.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 118 263.6 | Nov 2011 | DE | national |
