DEVICE FOR THE UTILISATION OF WAVE ENERGY

Abstract: The invention relates to a device for the utilisation of wave energy. To this end the device according to the invention comprises a rotor chosen from the group comprised of a Darrieus rotor and a Well's rotor which rotors are submerged in water and when in operation, are driven by waves. The device according to the invention preferably comprises both a Darrieus rotor and a Well's rotor.

Description: DEVICE FOR THE UTILISATION OF WAVE ENERGY The present invention relates to a device for the utilization of wave energy. A great variety of such devices are known, some of which are located just below the surface of the sea. It is the object of the present invention to provide a device of the type mentioned in the preamble, which is substantially insensitive with respect to the direction from which the waves are coming. It is also an objective to provide a device that is relatively light, while nevertheless being well able to withstand the sometimes considerable stresses. To this end the device according to the invention is characterized in that the same comprises a rotor chosen from the group comprised of a Darrieus rotor and a Well's rotor, which rotor is equipped to be driven by waves while being submerged in a body of water. Applicant has found that by using a Darrieus rotor or a Well's rotor, the changing currents around a wave can be used for the generation of energy. The use of a Darrieus rotor for the generation of energy with the aid of hydropower is known for running water, but not for the utilization of wave energy. Well's rotors are known in devices for the utilization of wave energy (see GB 2,250,321). There, an air chamber is provided at a (steep) rocky coast, closed off by the surface of the sea, and in a channel which is in communication with the atmosphere, a Well's rotor is provided. The movement of waves in the chamber provides a reciprocating air flow through the channel, causing the Well's rotor to rotate. According to a first important preferred embodiment, the device is provided both with a Well's rotor and with a Darrieus rotor and the axes of rotation coincide. In this way the Darrieus rotor will start more easily if the rotor has been idle after a period of absence of (or sufficiently strong) waves. In addition, the different directions of current in and around waves are utilized more efficiently so that more wave energy can be utilized. According to a very important preferred embodiment the turbine blades of the Well's rotor are with respect to the axis of rotation, distally connected with the blades of the Darrieus rotor. In this way the blades of the Well's rotor are used as construction element for the blades of the Darrieus rotor. Instead of construction elements that increase friction without contributing to the generation of energy, this provides cross arms that contribute to the generation of energy. Preferably therefore, all the blades of the Darrieus rotor are connected with blades of the Well's rotor. According to a favorable embodiment, the Darrieus rotor has a spiral-like blade. In this way sudden great forces can be avoided. Although the device can be used to generate mechanical energy, for example, by means of driving shafts, or hy- draulically or pneumatically, the device preferably comprises a generator for the generation of electricity. The invention also relates to a method for the utilization of wave energy, using a device according to the invention, which device is placed into a body of water in which waves occur naturally. Basically, such a body of water is a sea or an ocean, although a lake that may or may not be fresh water and on which wind causes waves to occur, is also suitable. The axis of rotation is preferably vertical . In this way the device is able to make optimal use of the wave energy in the waves . The device is preferably adjustable in height and is adjusted such that all the rotor blades are submerged under the water surface of the body of water. This achieves not only that the device is positioned just beneath the water surface (where the wave energy is) al- lowing it to be adjusted to possible tidal action, but that in the event of storm, the device can be submerged deeper under the water surface so that it does not become damaged and is able to continue to generate energy. The invention will be elucidated with reference to the following exemplary embodiment and the drawings, in which Fig. 1 shows a device according to the invention comprising a Well's rotor and a Darrieus rotor; Fig. 2 shows a cross-section through the device of Fig. 1 along line II-II; Fig. 3 shows a detail of the device shown in Fig. 1, wherein a Well's rotor blade is at its end connected with a Darrieus rotor blade. Fig. 4 a-c shows three alternative embodiments of a combination of a Well's rotor and a Darrieus rotor; Fig. 5 shows a floating device according to the invention; and Fig. 6 shows an alternative device according to the invention in two positions. In Fig. 1 a device 1 is illustrated, which comprises a pole 2 mounted in the sea bed A along which, for example hydraulically, an assembly 4 of rotor blades can be moved. The assembly 4 is rotatable about an axis of rotation which coincides with the centre line through the pole 2. The assembly 4 comprises four Darrieus rotor blades 5 (5', 5'' and 5''' are visible; 5'''' is behind the pole) and four Well's rotor blades 6 (6' and 6'' are visible, 6' ' ' and 6' ' ' ' are not visible). In the illustrated embodiment, the Well's rotor blades 6 are positioned horizontally, but this is not a prerequisite. The Well's rotor blades 6 may also be positioned at an angle, either upward or downward. In the embodiment shown, the Darrieus rotor blades 5 are placed perpendicularly to the sea bed A, but this is not a prerequisite. The Dar- rieus rotor blades 5 may also be positioned at an angle with the axis of rotation such as to form a conical surface of revolution. In order to reduce peak loads on the Darrieus rotor blades 5, a pair of Darrieus rotor blades 5 connected via Well's rotor blades 6 may be rotated somewhat with respect to the centre line of the Well's rotor blades 6. Fig. 1 also shows a maintenance platform, which is of no importance with respect to the invention itself. Fig. 2 shows a cross-sectional line along II-II in Fig. 1. One can see the Well's rotor blades 6' -6'''' as well as a cross section through the Darrieus rotor blades 5'- 5' ' ' ' . Fig. 2 shows that the assembly 4 rotates anticlockwise. At the front the Well's rotor blades 6 are thicker than at the rear (Fig. 3) . Within the scope of the present invention it is also possible for the Darrieus rotor blades 5 to be connected by means of an arm that has a wing profile either on top or underneath, in which case it is preferred that at least one arm having a wing profile on top as well as at least one arm having a wing profile underneath be present (not shown) . -However, for an optimal energy production it is preferred for each arm to have a wing profile both on top and underneath. In order to obtain a strong construction, the Dar- rieus rotor blades 5 and the Well's rotor blades 6 may form a frame in the form of, for example, a rectangle (Fig. 4a) . To avoid peak loads, the Darrieus rotor blades may also be spiral-shaped (the axis of rotation forming a virtual centre line. (See Fig. 4b) . A preferred embodiment is shown in Fig. 6. At their tops, the two devices shown there comprise blades 6 of the Well's rotor, which are connected with blades 5 of the Darrieus rotor. At the lower side of the device the blades 5 of the Darrieus rotor taper towards each other. There they may be connected with one another or, as illustrated, be connected with a vertically movable bearing ring 8. This provides a strong, and for the generation of energy very efficient construction (Fig. 6 at the left) . Advantageously the blades of the Well's rotor and the Darrieus rotor are, as il- lustrated, pivotingly connected by means of hinges 9, and near the axis of rotation the blades 6 of the Well's rotor may be moved down but preferably up. In the embodiment shown, the bearing ring 8 can be moved down (Fig. 6 at the right) . Such a construction allows all the blades 5, 6, for example, in the event of floating ice or very stormy weather to be brought into a substantially longitudinal form. Although in this position the device is long, it takes up little space. Moreover, in this position the arm (which in the illustrated iQ H- rt ø Pi H- 0 ft ) I- 1 ft ) X H- CO — * H- 0 0 I-. - Φ Hi (1 * 0 H- en TJ 0 en Φ 0 Ml ID 0 > Pi H- u rt •

Claims: CLAIMS 1. A device for the utilization of wave energy, characterized in that the device comprises a rotor chosen from the group comprised of a Darrieus rotor and a Well ' s rotor, which rotor is equipped to be driven by waves while be- ing submerged in a body of water. 2. A device according to claim 1, characterized in that the device is provided with a Well's rotor, whose axis of rotation coincides with the axis of rotation of the Darrieus rotor. - 3. A device according to claim 1 or 2, characterized in that the turbine blades of the Well's rotor are with respect to the axis of rotation, distally connected with the blades of the Darrieus rotor. 4. A device according to claim 2 or 3 , characterized in that the device comprises two Well's rotors, wherein blades of both Well's rotors are distally connected with blades of the Darrieus rotor. 5. A device according to one of the preceding claims 2 to 4, characterized in that all the blades of the Darrieus rotor are connected with blades of the Well's rotor. 6. A device according to one of the preceding claims, characterized in that the Darrieus rotor has a spiral-like blade. 7. A device according to one of the preceding claims, characterized in that the device comprises a generator for the generation of electricity. 8. A method for the utilization of wave energy, characterized in that the device according to one of claims 1 to 7 is placed into a body of water in which waves occur naturally. 9. A method according to claim 8, characterized in that the axis of rotation is vertical. 10. A method according to claim 8 or 9, characterized in that the device is adjustable in height and is ad- justed such that all the rotor blades are submerged under the water surface of the body of water.

Inventors: ROSSEN ERIC ARTHUR, SCHEIJGROND PETER CORNELIS, ROSSEN, ERIC, ARTHUR, SCHEIJGROND, PETER, CORNELIS
Applicants: ECONCERN BV, ROSSEN ERIC ARTHUR, SCHEIJGROND PETER CORNELIS, ROSSEN, ERIC, ARTHUR, SCHEIJGROND, PETER, CORNELIS
Application year: 2001
Main classification: F03B13
IPC codes: F03B13, F03B17