WO2008122867A2

WO2008122867A2 - System for exploiting the energy derived from wave motion

Info

Publication number: WO2008122867A2
Application number: PCT/IB2008/000818
Authority: WO
Inventors: Bruno Bortolo Buora
Original assignee: Nav Tek S.R.L.
Priority date: 2007-04-05
Filing date: 2008-04-02
Publication date: 2008-10-16
Also published as: WO2008122867A3

Abstract

A system (1) for exploiting the energy derived from wave motion, comprising at least one hull (2) provided with wave generation means (4) adapted to generate a breaking wave, energy generation means (20) being actuatable by the mass of water of the breaking wave.

Description

SYSTEM FOR EXPLOITING THE ENERGY DERIVED FROM WAVE

MOTION

Technical field

The present invention relates to a system for exploiting the energy derived from wave motion. More particularly, the invention relates to a system for exploiting the energy of wave motion which is capable of generating a wave which breaks in the required point. Background art

As is known, alternative energy sources, capable of providing so- called "clean" energy, with considerable benefits for the environment, are increasingly in demand.

One of the energy sources available to mankind is certainly the sea. Presently known solutions for exploiting the energy that can be obtained from marine wave motion, however, are currently not attractive from the point of view of constructive simplicity and implementation costs.

Moreover, the exploitation of waves and particularly of the breaking of a wave entails that a breaking wave whose impact against a fixed or movable structure produces a transfer of energy must indeed be always available. Moreover, the impact of the breaking wave may be excessive as regards the released energy and therefore may compromise the system designed to convert such energy. Disclosure of the invention

The aim of the present invention is to provide a system for exploiting the energy derived from wave motion which allows to generate in any marine weather conditions a breaking wave which can be exploited for an energy conversion, regardless of the position in which the waves normally break in the given body of water in which the system is located.

Within this aim, an object of the present invention is to provide a system for exploiting the energy derived from wave motion in which the oscillating or rectilinear motion of the energy generation means can be slowed automatically so as to exploit it to the fullest extent.

Another object of the present invention is to provide a system for exploiting the energy derived from wave motion which allows to impart to the mass of water to be exploited in order to obtain energy therefrom a horizontal translational motion which is parallel to the seabed.

Another object of the present invention is to provide a system for exploiting the energy derived from wave motion which allows to calibrate the number of waves that can be actually exploited in order to trigger pendulation or linear impact, so as to not trigger excessive oscillations which can lead to halting of the system due to excessively sudden reversals of the oscillating motion.

Still another object of the present invention is to provide a system for exploiting the energy derived from wave motion which is highly reliable, relatively simple to provide and at competitive costs.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a system for exploiting the energy derived from wave motion, characterized in that it comprises at least one hull provided with at least one protrusion which is adapted to generate a breaking wave, energy generation means being actuatable by the mass of water of said breaking wave. Brief description of the drawings

Further characteristics and advantages of the invention will become better apparent from the description of preferred but not exclusive embodiments of the system according to the present invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic side view of a first configuration of the system for exploiting energy according to the present invention;

Figures 2 and 3 are views of the system of Figure 1 in further operating positions; Figure 4 is a plan view of an example of an embodiment of the system according to the invention;

Figure 5 is a side view of another embodiment of the system according to the invention; Figure 6 is a view of a third embodiment of the system according to the present invention;

Figure 7 is a view of a fourth embodiment of the system according to the present invention;

Figure 8 is a view of a fifth embodiment of the system according to the present invention;

Figure 9 is a view of a sixth embodiment of the system according to the present invention;

Figure 10 is a view of a detail of the system according to the present invention; Figure 11 is a view of another embodiment of the system according to the present invention;

Figure 12 is a view of a detail of another embodiment of the system according to the present invention;

Figure 13 is a view of another detail of an embodiment of the system according to the present invention;

Figure 14 is a view of another embodiment of the system according to the present invention;

Figure 15 is a view of another embodiment of the at least one hull used in the present invention; Figure 16 is a side elevation view of another embodiment of the system according to the present invention;

Figure 17 is a top plan view of the system according to the invention shown in Figure 16; Figure 18 is a view of a detail of the turbine used in the system according to the invention shown in Figures 16 and 17;

Figure 19 is a plan view of another embodiment of the system according to the present invention. Ways of carrying out the invention

With reference to the figures, the system according to the present invention, generally designated by the reference numeral 1, comprises at least one hull provided with a protrusion 4 which is adapted to generate a breaking wave and preferably a pair of hulls 2 and 3 arranged mutually side by side and connected by at least one protrusion 4, which is adapted to be arranged at an angle with respect to the seabed and is adapted to constitute a passage for guiding a wave. The protrusion 4 can be tilted, for example in an adjustable manner, with respect to the seabed, so as to create a ramp which allows to generate a breaking wave even in the absence of waves in a given stretch of sea.

The adjustable tilting protrusion 4 therefore allows to modulate the impact of a mass of water and induce it to be guided between the two hulls 2 and 3.

Conveniently, the two hulls 2 and 3 can be two hulls of a vessel such as a catamaran, with the protrusion 4 acting as an element for structural connection between the two hulls 2, 3 or, as an alternative, the two hulls 2, 3 can be constituted by two independent vessels, such as for example two ships arranged mutually side by side and moored so as to stay parallel to each other and connected by at least one protrusion 4 which is adapted to constitute a barrier for generating a breaking wave.

The two hulls must be connected to each other not only by the protrusion 4 but also by an adapted structure, so as to make them jointly connected and adapted to withstand violent impacts.

Conveniently, a pumping system is provided on board of at least one of the two hulls 2, 3 and is constituted by a plurality of pistons 20 which are connected to a single line 5.

Each piston 20 is connected, at its lower end, to pusher means 7, conveniently constituted for example by a plate or baffle which is adapted to receive thrust from the wave that breaks against the protrusion 4, so as to move the plate from an inactive position, as shown in Figure 1, in which the stem of the piston is at the top dead center, to an active position, in which the plate 7 is struck by the breaking wave and the stem of the piston is in the maximum compression position, i.e., at the bottom dead center, as shown in the subsequent figures. Therefore, the plates 7 allow to make each piston 20 perform the pumping stroke, with a succession produced by the passage of the breaking wave on the protrusion 4.

The return of the piston 20 to the inactive position occurs simply by gravity, when the wave passes, i.e., when the wave retreats, allowing the plate 7 pivoted at a point 8 to return to the inactive position.

Conveniently, the protrusion 4 is blended with a bottom plane 10, which is suitably inclined between the two hulls so as to allow the outflow of the wave once it has struck the inclined protrusion 4.

Advantageously, in the case of the presence of a plurality of inclined protrusions 4 which are mutually spaced, the bottom portion 10 might not be continuous, but there might be a bottom portion 10 for each inclined protrusion 4, with a space between adjacent bottom portions 10 so as to allow the wave to be caught again with a subsequent inclined protrusion 4.

The pistons are conveniently connected to a hydraulic motor for generating electric power which can then be transferred to dry land and by means of a single cable.

Conveniently, both in the case of two separate hulls 2 and 3 and in the case of two actual ships arranged mutually side by side, the hulls or ships must be anchored appropriately so as to provide lateral stabilization as well as heading stabilization. If two mutually side-by-side ships are used, they are not affected by the wave motion unless it is truly violent or stormy, and therefore the ships are practically stationary while the generated "breaking" wave motion passes between the two ships. Conveniently, it is possible to provide a front protrusion 4 which is inclined to a greater or smaller extent depending on marine weather conditions, varying for example the load that the two side-by-side ships may have on board, by filling for example tanks of such ships by means of ordinary pumps, even using seawater. Figure 5 is a view of this last embodiment, with the tanks shown in broken lines.

With reference now to Figures 6 to 15, further embodiments of the system according to the invention are described.

The system according to the present invention can therefore comprise, according to a third embodiment thereof, a vessel 100 provided with energy generation means, such as for example an oscillating pendulum or a piston system.

The system according to the invention further has wave generation means, which are constituted conveniently for example either by a ramp whose inclination is fixed or is adjustable and which is arranged for example on the seabed and for example has an inclined barrier which is adapted to generate a wave; or a barrier 120 which can be adjusted hydraulically or by means of a chain/cable and is arranged at the seabed, or, as shown in Figure 7, a floating barge 130 which is anchored to the seabed and is connected to a movable baffle 140, whose inclination can be adjusted so as to generate a wave, or also, as shown in Figure 8, by a pair of barges

150 and 160, which are parallel and are connected to a movable baffle 140a whose inclination can be adjusted so as to allow to guide the wave between the two barges 150 and 160 and allow the subsequent cresting of the wave due to the presence of the movable baffle 140a. Figure 9 is a view of a variation in which the barges 150 and 160, designated by the reference numerals 150a and 160a in this case, are contoured so as to have at the front a flared portion 170 and 180 respectively, so as to form a guide for the entry of the wave, which thus strikes the movable baffle 140a.

In this case also, the barges help to be anchored to the seabed.

The wave generation means described above allow to generate the wave in any desired position, without therefore being constrained to a precise point in which the vessel 100 is to be moored so that the wave breaks directly against the vessel.

In this manner, the problem constituted by tides is simplified, since it is possible to act always in the same point with the vessel without it shifting, but by adjusting the movable baffle 140, 140a so as to make the waves break right at the stem of the vessel 100. The support barges 150, 150a and 160, 160a can also be very long; in this manner, in addition to augmenting the wave at the surface by means of the movable baffle 140, 140a on the seabed, one also achieves an acceleration of the wave motion guided between the two barges, which when necessary can become useful in the various trim combinations. Conveniently, the vessel 100 can be provided with peaks which can be filled with water in order to stabilize the system and trigger a controlled oscillation of the vessel which allows to reduce the risk of halting the pendulation due to the frequent motion reversals.

In this case, there can be at least one forepeak 110 and at least one afterpeak 111, which can be filled by means of adapted pumps, and at least one peak 112 which is arranged at the bilge of the vessel 100 and is also filled with liquid.

The peaks 110 and 111 can be filled permanently with liquid so as to stabilize the oscillation, while the liquid in the peak 112 moves depending on the inclination that the vessel 100 assumes with respect to a vertical axis thereof, i.e., depending on the pitching motion.

The anchoring point of the vessel 100 can be selected conveniently so as to anchor the vessel at its center of gravity, thus allowing maximum oscillation (pitching) for the vessel. Figure 11 is a view of an anchoring point 115 provided at the center of gravity of the vessel with the possibility to apply tension, by means of a tensioning cable 116, to the anchoring line 117.

Conveniently, the hermetic forepeak and afterpeak 110, 111 can be provided with quick discharge valves 118. In order to control the movement of the liquid within the central peak

112, it is possible to provide adapted adjustable baffles 119, which allow to brake the liquid, avoiding intense motion, and therefore the uncontrollability of the system.

The pumping means can be constituted, as shown for example in Figure 10, by an oscillating pendulum 125, which actuates piston means

126, or can be constituted, as shown for example in Figure 12, by a pumping system which is constituted by a cylinder 130 with a corresponding piston

131 which is connected by means of a cable 132 to the seabed, passing through a tube 133 which is welded so as to pass through the hull, so as to allow the cable 132 to exit from the hull substantially at its center of gravity and thus be anchored to the seabed.

In this case, pumping without transmissions occurs and only one useful stroke is provided.

As an alternative, as shown in Figure 13, it is possible to have a plurality of pumping means, designated by the reference numeral 135, with stems of the respective pistons connected to winches 136 which allow to take up a line 138 for calibrating the stroke as a function of the positive or negative lever arm, thus exploiting also the short movements with longer strokes of the pumping center. This takeup by means of the winch 136 and optionally a winch 137 which takes up the central mooring line 138 allows to compensate for tidal variations.

Figure 14 is instead a view of a variation in which there are a plurality of pumping systems, for example two, which are arranged respectively at the stem and at the stern of the vessel 100, as an alternative to the pendulum system shown in Figure 10.

Advantageously, the forepeak and afterpeak can be constituted by air pockets, which as a consequence of the movement of the liquid in the central or bilge peak and of the presence of overpressure valves, are discharged when the liquid strikes the air pocket and therefore the air is conveyed to the peak of the opposite end of the vessel, exploiting the water hammer that occurs as a consequence of the reversal of the motion of the vessel, i.e., by exploiting stem or stern pitching that the vessel performs due to the impact of the wave.

In practice it has been found that the system according to the invention fully achieves the intended aim and objects, since it allows to generate a wave in the desired position, without having to move the anchoring of the vessel depending on the tidal conditions.

The system thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept. Thus, for example, the vessel 100 can be of the catamaran or trimaran type, with at least one movable baffle 140a between the two or more hulls, so as to receive in any case the impact of the wave and yet, by moving the baffle to a position which is substantially parallel to the surface of the water, be able to perform the return stroke, due to the impact with a wave, with the lowest possible friction.

This constructive solution is shown in Figure 15.

Figure 16 is a view of another embodiment of the system according to the present invention. In this embodiment, also shown in Figure 17 in plan view, the wave generation means comprise an inclined plane 200, which is adapted to be adjusted in terms of incidence so as to generate a wave which breaks at the selected point, regardless of the presence or not of waves in a given stretch of sea.

The wave generation means 200 are conveniently accommodated within a floating unit 300 and are connected to such unit by means of at least one pair of pumping means 210, which are arranged so that when the mass of water passes at the wave generation means 200 the stems of the pumping means 210 perform a descent stroke, and when the energy of the mass of water is released the wave generation means 200 return in position upwardly, thus allowing the stems of the pumping means 210 to perform an upward stroke.

Conveniently, the floating unit 300 is anchored to the seabed and is provided with means for throttling devices, tide compensation elements, conveniently constituted for example by pumping means 220 which are adapted to cushion the passage of the mass of water which is incident to the wave generation means 200 and therefore allow the momentary sinking of the floating unit 300 and its subsequent upward motion following the passage of the mass of water.

Conveniently, the floating unit 300 is provided with at least one turbine 230, of a type such as the one shown in Figure 18, in which the reference numeral 230 designates the wheel turbine, the reference numeral 231 designates a flap for protecting the flow and the reference numeral 232 designates flow redirection means, and finally the reference numeral 234 designates a collection tank.

In this condition, the flow of water, designated by the reference numeral 235, is guided, after the incident passage over the generation means 200 within the wheel turbine 230, with the excess part unable to enter the turbine which passes to the tank 234, to enter a turbine, as shown by the reference numerals 236. In this manner, the mass of water that strikes the wave generation means is exploited entirely to actuate the turbine 230. Substantially, the turbine used in the system according to the invention allows to cope with the problem of the pulsed flow of breaking waves, achieving the result that the part of the wave enters the part of the turbine along the directrix designated by the reference numeral 235, while the excess part accumulates in the collection tank 234, then flowing out into the turbine at a later time through an auxiliary duct.

In this manner, an extension of the active step is achieved and it is therefore possible to cover a time interval between one breaking wave generation and the next.

Conveniently, the wave generation means constituted by the inclined plane 200 do not protrude at sea level, since their function is to concentrate the energy of the wave motion and only in this manner is it possible to cause the rise of the wave, which by breaking releases filling energy to the mass of water which is no longer in vertical motion but is in horizontal translational motion. The system according to the invention can be anchored normally, because the waves in the vast majority of cases always lie parallel to the coast regardless of the direction of the wind.

For high-power plants arranged in the open sea, since the wave motion is not oriented by the coastline, the direction of the wave motion can vary, and it is therefore important for the unit 300 to turn into the wind with a single oversized anchoring which can act as a collector for sending the energy to dry land.

Of course, the unit according to the present invention can be flanked by similar units, so as to have with three floating units two energy generation systems, with four floating units three systems, and so forth.

The system according to the invention further has a generator 240 which is adapted to be actuated by the turbine 230.

Figure 19 is a view of another embodiment of the system according to the present invention, in which the wave generation means, designated in this case by the reference numerals 400, comprise at least one inclined plane, in the case shown in the figure three inclined planes, provided with means for throttling the generated wave so as to exploit the mass of water that strikes the inclined plane.

The wave throttling means are constituted by step-like contoured portions 410 of the inclined plane 400, so that each step-like contoured portion is affected by a subsequent wave portion to move the mass of water in succession to the turbine 230.

The system according to the present invention can also provide for the presence of wave generation means for example inserted between a pair of walls which are fixed to the seabed, so that the wave generation means, i.e., for example an inclined plane whose inclination can be adjusted as described earlier, receive the mass of water that derives from marine wave motion and convert it into a breaking wave without requiring a floating system. The system according to the present invention can have a combination of the solutions described in the preceding embodiments, although this combination might not be described here expressly.

All the details may further be replaced with other technically equivalent elements. The disclosures in Italian Patent Applications no. MI2007A000707 and MI2007A002235, from which this application claims priority, are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A system for exploiting the energy derived from wave motion, characterized in that it comprises at least one hull provided with wave generation means adapted to generate a breaking wave, energy generation means being actuatable by the mass of water of said breaking wave.

2. The system according to claim 1, characterized in that said wave generation means comprise at least one protrusion.

3. The system according to claim 1, characterized in that it comprises a pair of hulls which are arranged mutually side by side and are connected one another by said at least one protrusion adapted to generate a breaking wave, said protrusion being blended with an inclined portion toward the stern of said hulls, in order to guide the breaking mass of water.

4. The system according to claim 1 or 2, characterized in that said at least one protusion is adjustable in its inclination with respect to the seabed.

5. The system according to claim 3, characterized in that said two hulls are the two hulls of a vessel such as a catamaran.

6. The system according to one or more of the preceding claims, characterized in that said two hulls are two ships which are anchored so as to be mutually parallel.

7. The system according to one or more of the preceding claims, characterized in that said energy generation means comprise pumping means which comprise at least one piston which is connected to a baffle which can move when the mass of breaking water breaks, said baffle being connected to said piston, in order to apply a pumping action as a consequence of the passage of said breaking mass of water.

8. The system according to claim 1, characterized in that said at least one hull is a vessel which is adapted to be anchored, said vessel being provided with motion generation means which are adapted to be triggered by the oscillation or linear motion that said vessel receives when a wave breaks against said vessel.

9. The system according to one or more of the preceding claims, characterized in that said at least one protrusion comprises a fixed obstacle which can be positioned at the seabed, proximate to said at least one hull.

10. The system according to one or more of the preceding claims, characterized in that said at least one protrusion comprises a barrier whose inclination can be adjusted and which is arranged at the seabed.

11. The system according to one or more of the preceding claims, characterized in that said wave generation means comprise at least one floating barge which is anchored in a fixed position and is adapted to actuate a movable baffle which is arranged so that one end is fixed to the seabed.

12. The system according to one or more of the preceding claims, characterized in that it comprises a pair of parallel barges and a movable baffle which is connected to said barges and is connected at one end to the seabed.

13. The system according to one or more of the preceding claims, characterized in that said barges are contoured so to have a guide for the wave which enters between said barges and strikes said movable baffle.

14. The system according to one or more of the preceding claims, characterized in that said motion generation means comprise at least one cylinder with at least one piston which can slide therein and in which the stem of the piston is connected directly to the seabed, said stem being connected to said seabed by a line which passes through a tube which is provided so as to pass through the hull of said vessel.

15. The system according to one or more of the preceding claims, characterized in that said motion generation means comprise at least one piston which is installed on board of said vessel and is connected to a winch for taking up a mooring line which anchors said vessel to the seabed, said winch being adapted to take up said line as a consequence of the variation of the tide.

16. The system according to one or more of the preceding claims, characterized in that said vessel is provided with at least one central peak which is adapted to contain a liquid, said liquid being able to move within said peak as a consequence of the oscillation of said vessel.

17. The system according to one or more of the preceding claims, characterized in that said vessel comprises at least one forepeak and one afterpeak, which are adapted to be filled with liquid in order to stabilize said vessel.

18. The system according to one or more of the preceding claims, characterized in that it comprises at least one forepeak and one afterpeak which are adapted to be filled with air.

19. The system according to one or more of the preceding claims, characterized in that said vessel is of the catamaran or trimaran type, at least one movable baffle being arranged between the hulls of said vessel.

20. The system according to one or more of the preceding claims, characterized in that said breaking wave generation means are connected to a pair of pumping means.

21. The system according to one or more of the preceding claims, characterized in that said at least one hull is provided with stabilizing means which compensate for tides.

22. The system according to one or more of the preceding claims, characterized in that said breaking wave generation means comprise at least one inclined plane which is provided with wave throttling means provided by means of steps defined in said inclined plane.

23. The system according to one or more of the preceding claims, characterized in that it comprises a turbine provided with flow redirection means in order to guide a portion of flow of water into the turbine and an excess portion into said turbine at a later time.