ES2636863T3 - Floating Wave Energy Converter - Google Patents

Abstract

Floating wave energy converter for converting wave energy into electricity, the wave energy converter comprising an enveloping body (2) adapted to oscillate in response to wave motion and extending between one extreme bow (3) and a stern end (4) with the bow end (3) thereof adapted to face the waves when in operation, a bow-facing lower part (27) of the adjacent shell (2) to the bow end (3) thereof inclined in the stern direction, generally downward, an air chamber (15) formed in the casing (2) adjacent to the bow end (3) thereof, a housing duct of the water (16) formed in the housing (2) and extending aft from the air chamber (15) to accommodate water entering and leaving the air chamber (15) as the housing (2) oscillates in response to wave motion to vary the water level and n the air chamber (15), the water accommodation duct (16) terminating in a water accommodation opening (17) located aft of the air chamber (15) at the aft end (4) of the body envelope (2), an air housing duct (21) to accommodate air entering and leaving the air chamber (15) in response to the variation of the water level therein, a conversion means (22) to convert the energy of the air driven through the air housing duct (21) in response to the variation of the water level in the air chamber (15) into rotational mechanical energy, characterized in that a first stabilizer plate (28) is extends below the waterline (19) of the shell (2) in a forward direction, generally downward from the lower forward-facing portion (27) of the shell (2) at a certain angle relative to the itself adjacent to the bow end (3) of the housing (2) to control movement pitch and lift of the housing (2) to maximize the efficiency of converting the motion of the housing (2) in water into usable energy.

Description

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DESCRIPTION

Wave energy converter, floating

The present invention relates to a floating wave energy converter and a method for improving the efficiency of a floating wave energy converter.

Wave energy converters to convert wave energy, for example, wave energy at sea, in a lake or in other extensions of water into mechanical rotational energy are known. In general, mechanical rotational energy is used to drive an electric generator to generate electrical energy. Said wave energy converters are disclosed in the European Patent Description No. 0.950.812 of Masuda et al., The U.S. Patent Description. No. 4,741,157 to Nishikawa and the U.S. Patent Description. No. 4,858,434 of Masuda, granted to Nishikawa. All such wave energy converters disclosed in these three prior art descriptions comprise a wrapping body that extends between a bow end and a stern end and is moored so that the bow end is oriented towards the approaching waves. The mooring of the enveloping body is arranged so that the enveloping body oscillates nodding in a direction from bow to stern in response to the passage of waves. An upwardly extending air chamber is formed in the enclosure adjacent to the bow end thereof and a water housing conduit extends aft of the air chamber and ends in an opening that houses water in the stern to accommodate water entering and leaving the air chamber as the casing oscillates. An air housing conduit that extends from the air chamber houses air entering and leaving the air chamber as the level of water within the air chamber varies as a result of the oscillating movement of the housing. A turbine located in the air housing duct is driven by the air that passes through the air housing duct in response to the rise and fall of the water level in the air chamber to drive an electric generator, which in turn It generates electricity from the oscillating movement of the enveloping body. A material for the flotation is located at the stern of the air chamber, on the water housing duct in the wave energy converters of the three patent descriptions of the prior art. However, in the two U.S.A. of the prior art, the material for the flotation is also located extending forward from the bow end of the body of the wave energy converters.

Consequently, with any of the energy converters of the moored waves by means of a suitable mooring system with the bow end of the enveloping body oriented towards the approaching waves, the passage of the waves causes the enveloping body to oscillate with a movement from head to bow direction, which in turn causes water to flow in and out of the air chamber in each cycle of oscillation of the enclosure through the water housing duct. When water flows in and out of the air chamber, the water level of the air chamber rises and falls. This results in the air being propelled sequentially outward and inward in the air housing duct. Depending on the type of turbine used, the turbine rotates in the same direction regardless of the direction of the air flow in the air housing duct or, alternatively, it can rotate only in one direction in response to the air being driven towards outside or inwards in the air housing duct. In such cases, in general, a valve system and the corresponding ducts are arranged in order to convert the flow in the air housing duct in the two directions so that it flows through the turbine in a single direction.

In certain cases, the wave energy converters described in the three descriptions of the prior art may be provided with one or several air chambers and one or more water housing ducts and, usually, when equipped with more than an air chamber, are provided with the corresponding number of water housing ducts to accommodate the water in the respective corresponding air chambers.

Even when said wave energy converters act to convert wave energy into mechanical rotational energy that can be used to drive an electric generator to, in turn, generate electricity, in general, said wave energy converters they suffer two serious drawbacks, first of all, they tend to be relatively inefficient in the conversion of wave energy into electrical power and, in particular, in the conversion of wave energy into mechanical rotational energy and, secondly, they tend to be relatively unstable, in particular, in relatively turbulent waters where the height of the wave is relatively high. Even when an attempt has been made in the wave energy converter disclosed in European Patent Description No. 0.950.812 to increase the efficiency of the conversion of wave energy into mechanical rotational energy, the converters of Wave energy disclosed in the three descriptions of the prior art still tend to be relatively inefficient.

The description of Masuda's PCT application published under number WO 84/01603 also discloses a wave energy converter that is similar to that disclosed in the U.S.A. No. 4,858,434.

The description of British Patent No. 2,020,756A of Woodilla discloses an energy converter of the

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waves comprising a central balancing chamber to which the air is drawn through an air inlet and a turbine in response to the movement of the waves. Three arms extend radially from the balancing chamber and carry corresponding floats that are equidistant circumferentially around the balancing chamber. A conduit in each radial arm communicates the central balancing chamber with an air chamber in each of the corresponding floats. A vertical duct extends downward from the air chamber in each float. Woodilla floats rise and fall in response to the passage of the waves, which results in the rise and fall of water in vertical ducts. The lowering of the water level in the vertical ducts of the floats results in the air being drawn through the corresponding radial ducts from the central balancing chamber. This, in turn, results in the air being drawn through the turbine. Buffer discs extend around the floats to avoid undesirable oscillations of the float.

Therefore, there is a need for a wave energy converter that addresses at least some of the problems of wave energy converters of the prior art and there is also a need to disclose a method for improving the efficiency of said wave energy converters to convert wave energy into mechanical rotation energy.

The present invention is directed to providing said wave energy converter, and the invention is also directed to a method for improving the efficiency of a floating wave energy converter.

According to the invention, a floating wave energy converter is disclosed to convert wave energy into electricity according to claim 1, the wave energy converter comprising a wrapping body adapted to oscillate in response to movement. of the waves and that extends between a bow end and a stern end, with the bow end thereof adapted to be oriented towards the waves when it is in operation, a lower part facing the bow of the surrounding body adjacent to the end of bow thereof bows in the direction of the stern, in general, downward, an air chamber formed in the surrounding body adjacent to the bow end thereof, a water housing conduit formed in the enveloping body and extending aft from the air chamber to accommodate water entering and leaving the air chamber as the enveloping body oscillates in response to the movement of the waves to vary the level that of water in the air chamber, terminating the water housing conduit in a water housing opening aft of the air chamber at the stern end of the housing, an air housing conduit for accommodating air entering and out of the air chamber in response to the variation of the water level thereof, conversion means for converting the energy of the air, which is driven into the air housing duct in response to the variation of the water level in the air chamber, in mechanical rotation energy, where a first stabilizer plate extends below the floating line of the enclosure body in a direction, generally descending forward from the lower part facing forward of the enveloping body in a certain angle with respect thereto adjacent to the bow end of the enclosure to control the movement of elevation and pitch of the enclosure to maximize the efficiency of the c onversion of the movement of the enveloping body in water into usable energy.

Preferably, the first stabilizer plate extends from the housing to a level below the waterline. Advantageously, the first stabilizer plate extends, in general, transversely to the bow-to-stern direction of the housing.

In one embodiment of the invention, the first stabilizer plate is extended from the bow end of the enclosure body at an angle with the vertical in the range of 30 ° to 60 ° when the enclosure body is floating with the water housing conduit located substantially horizontal. Preferably, the first stabilizer plate extends from the bow end of the enclosure body at an angle to the vertical in the range of 40 ° to 50 ° when the enclosure body is floating with the water housing conduit located substantially horizontal. Advantageously, the first stabilizer plate extends from the bow end of the enclosure body at an angle with the vertical of approximately 45 ° when the enclosure body is floating with the water housing conduit located substantially horizontal.

Theoretically, the first stabilizer plate extends substantially across the entire transverse width of the housing adjacent to the bow end thereof.

Advantageously, the forward inclined part of the enclosure is located below the waterline.

In one embodiment of the invention, the inclined forward-facing part of the enclosing body is inclined with respect to the vertical at an angle in the range of 30 ° to 60 ° when the enveloping body is floating with the water housing conduit located substantially horizontal. Preferably, the forward-facing inclined part of the wrapping body is inclined with respect to the vertical at an angle in the range of 40o to 50o when the wrapping body is floating with the water housing conduit located substantially horizontal. Advantageously, the forward-facing inclined part of the enveloping body is inclined with respect to the vertical at an angle of approximately 45 ° when the enveloping body is floating with the

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water housing duct located substantially horizontal.

Advantageously, the first stabilizer plate extends from the inclined part facing the front of the enclosure body at an angle of approximately 90 ° with respect thereto.

In another embodiment of the invention, the first stabilizer plate is reinforced with at least one reinforcement plate that extends between the first stabilizer plate and the housing. Preferably, the first stabilizer plate is reinforced by a series of separate reinforcing plates that extend between the first stabilizer plate and the housing.

In a further embodiment of the invention, bow ballast means are arranged adjacent the bow end of the wrapping body to stabilize the wrapping body. Preferably, the bow ballast means are located ahead of the air chamber. Advantageously, the bow ballast means are located above the level of the first stabilizer plate.

In one embodiment of the invention, the bow ballast means is extended in an upward direction from the level at which the first stabilizer plate is extended from the bow end of the wrapping body.

Preferably, the bow ballast means are adjustable to selectively adjust their weight.

In one embodiment of the invention, the bow ballast means comprise a ballast reservoir to accommodate ballast therein and, advantageously, the ballast reservoir is adapted to accommodate water ballast.

In another embodiment of the invention at least a second stabilizer plate is extended from the surrounding body and reacts to the movement of the waves passing through the surrounding body to keep the surrounding body with the bow end thereof oriented towards the waves. Preferably, the at least one second stabilizer plate extends in one direction, generally from bow to stern of the enclosure. Advantageously, the at least one second stabilizer plate extends in an upward direction from the housing. Theoretically, at least, the second stabilizer plate is located towards the stern end of the housing.

In one embodiment of the invention, a pair of second separate stabilizer plates extend from the housing.

Preferably, the air chamber extends in an upward direction from the water housing conduit adjacent to the bow end thereof.

In another embodiment of the invention, floating means are arranged to keep the shell floating in the water. Preferably, the floating means are located at the stern of the air chamber. Advantageously, the floating means are located on the water housing duct. Theoretically, the floating means extend from an aft position of the air chamber and end at an intermediate stern end between the air chamber and the stern end of the enclosure.

In one embodiment of the invention, the floating means terminate at their stern end closest to the air chamber on the respective opposite side edges of the enclosure body than at the intermediate position of the side edges thereof. Preferably, the flotation means terminate at its stern end closest to the stern end of the shell in a position halfway between the opposite side edges of the shell.

In one embodiment of the invention, the stern end of the floating means is substantially curved as seen in the plan. Advantageously, the aft end of the flotation means is substantially semicircular seen in plan.

Preferably, the floating means are located adjacent to the air chamber.

In an embodiment of the invention, the flotation means comprise a float tank.

In another embodiment of the invention, the flotation tank is adapted to be filled with air. Alternatively, the float tank is adapted to be filled with an expanded plastic float material.

In one embodiment of the invention, the conversion means for converting the air that is being driven through the air housing duct into a rotational movement comprises a turbine. Preferably, the turbine is a self-converting turbine so that regardless of the direction of the air flow passing through the turbine, the turbine rotates in only one direction. Advantageously, the conversion means are placed in the duct. Theoretically, the conversion means are coupled to an electric generator.

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In one embodiment of the invention, the conversion means are coupled in line with the generator. Preferably, the generator is located in the air housing duct.

In one embodiment of the invention, at least two air housing ducts are arranged. Preferably, conversion means are located in each air housing duct.

In another embodiment of the invention, a series of parallel water housing ducts are formed in the housing. Preferably, a series of air chambers are formed in the housing. Advantageously, the corresponding air chamber is arranged in each water housing duct.

In another embodiment of the invention, a manifold is arranged to communicate the air chambers with one or more air ducts.

In a further embodiment of the invention, coupling means are arranged in the wrapping body to couple the wrapping body to a mooring system with the bow end of the wrapping body oriented towards the waves. Preferably, the coupling means for coupling the housing to the mooring system comprises bow coupling means located at the bow end of the housing. Advantageously, a pair of bow coupling means are arranged on the respective opposite sides of the bow end of the wrapping body to couple the wrapping body to the mooring system. Advantageously, the coupling means for coupling the housing to the mooring system comprises stern coupling means located at the stern end of the housing. Theoretically, a pair of separate aft coupling means are arranged.

The advantages of the invention are many. The wave energy converter, floating, according to the invention, is particularly efficient and has been found in comparative tests that is considerably more efficient than the floating wave energy converters of the prior art of a substantially similar type and Thus, the wave energy converter according to the invention provides a significantly improved power output than that which can be obtained from the prior art converters.

The arrangement of the first stabilizer plate is considered to contribute significantly to the improvement of the efficiency of the wave energy converter according to the invention. The first stabilizer plate is considered to improve the relative movement between the wave energy converter and the wave movement in a controlled manner and, in particular, the lifting and pitching movement of the wave energy converter, and maximizes the rise and fall of the water level within the air chamber which, in turn, maximizes the efficiency of the conversion of the movement of the wave into mechanical rotational energy and, in turn, maximizes the power output of the converter Wave energy. It is also considered that the improved efficiency and power output of the wave energy converter according to the invention are achieved by a combination of the arrangement of the first stabilizer plate and the floating means and, in particular, by the location of the first stabilizer plate in relation to the situation of the floating means, by means of which the first stabilizing plate is located in front of the air chamber and the floating means are located aft of the air chamber. Additionally, it is considered that the arrangement of the ballast means in the bow of the air chamber also contributes to the improved efficiency and, in turn, to the improved power output of the wave energy converter according to the invention. It is considered that the combined effect of the first stabilizer plate, the floating means and the ballast means act together to exert additional control of the relative movement between the wave energy converter and the movement of the waves and, in particular, of the movement of elevation and pitching of the wave energy converter in order to improve the efficiency and power output of the wave energy converter according to the invention.

Additionally, the wave energy converter according to the invention is particularly stable in the water and is particularly stable in relatively rough sea conditions in which the waves are relatively high, and the wave energy converter has been found according to The invention is stable in waves of significant height up to at least sixteen meters high. It is considered that the stability of the wave energy converter according to the invention is achieved by the provision of ballast means and also contributes to the stability of the wave energy converter according to the invention by a combination of the first stabilizer plate and ballast means. In fact, the second stabilizer plate also plays a role in stabilizing the wave energy converter.

The invention will be more clearly understood from the following description of a preferred embodiment thereof, which is offered by way of example only, with reference to the attached drawings, in which:

Figure 1 is a schematic perspective view of a floating wave energy converter according to the invention for converting wave energy into electricity,

Figure 2 is another schematic perspective view of the wave energy converter of Figure 1,

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Figure 3 is a schematic side elevational view of the wave energy converter of Figure 1,

Figure 4 is a schematic elevational view of the rear end of the wave energy converter of Figure 1,

Figure 5 is a schematic top plan view of the wave energy converter of Figure 1,

Figure 6 is a schematic elevation view of the transverse section of the wave energy converter of Figure 1 on line VI-VI of Figure 4,

Figure 7 is a schematic elevation view of the cross section of the wave energy converter of Figure 1 on line VII-VII of Figure 3,

Figure 8 is a schematic top plan view of the transverse section of the wave energy converter of Figure 1 on line VIII-VIII of Figure 3,

Figure 9 is a schematic perspective view of the wave energy converter of Figure 1 shown in operation,

Figure 10 is a schematic side elevational view of the wave energy converter of Figure 1 in operation,

Figure 11 is a schematic side elevational view, similar to that of Figure 10 of the wave energy converter of Figure 1 in operation, and

Figure 12 is a graphical representation of the average power output represented with respect to the period of the wave obtained during the comparative tests between the wave energy converter according to the invention and a wave energy converter of the prior art.

Referring to the drawings, a floating wave energy converter is shown, according to the invention, indicated, in general, by reference numeral -1-, to convert the energy of the waves into mechanical energy of rotation and, in turn, in electricity. The wave energy converter -1- comprises a wrapping body -2- manufactured with a structural steel structure (not shown) that is lined with panels. The panels may be of any suitable material, for example, metal sheet or plate, concrete or plastic materials such as fiberglass and the like. In fact, the entire enveloping body can be made of reinforced concrete. The manufacture of said casing body from a structural steel structure and cladding with panels or other said materials is well known to those skilled in the art. The enveloping body -2- can float in the ocean and extends between a bow end -3- and a stern end -4-, and in operation it is moored with the bow end -3- oriented towards the waves to oscillate with a pitching action towards the bow and stern in response to the movement of the waves as these waves pass along the envelope body -2- from the bow end -3- to the stern end -4-.

The structural steel structure covered with panels of the casing body -2- comprises a pair of side walls -5- that extend upwards from a base -6- and are joined at the bow end -3- by a front wall -7-. An intermediate wall -8- extending in the upward direction joins the intermediate side walls -9- between the bow end -3- and the stern end -4-. An upper wall of the upper part -10- that extends between the front wall -7- and the intermediate wall -8- joins the side walls -5- towards the bow end -3- of the casing body -2-, while that the lower wall of the upper part -11- extending from the intermediate wall -8- to the stern end -4- of the enclosure -2- also joins the side walls -5-. The side walls -5-, the base -6-, the front wall -7-, the intermediate wall -8- and the upper and lower walls of the upper part -10- and -11- define a main hollow interior area - 12- inside the enclosure -2-.

Two partition walls -13- that are separated from the side walls -5- and that extend parallel from the front wall -7- to the stern end -4- of the enclosure -2- define together with the side walls -5 -, the front wall -7- and the intermediate wall -8-, three vertical air chambers -15- within the main hollow interior area -12- of the enclosure -2- adjacent to the bow end -3-. The partition walls -13- also define together with the side walls -5-, the base -6- and the bottom wall of the upper part -11-, three corresponding water-housing ducts -16- in the main hollow interior area -12- to accommodate water entering and leaving the air chamber -15- as the enclosure -2- oscillates in response to the movement of the waves. The water housing ducts -16- communicate with the corresponding air chambers -15- and extend aft from them to the stern end -4- of the casing body -2-, where they end at the openings -17 - respective water housing to accommodate water entering and leaving the air chambers -15-. The air chambers -15- extend in an upward direction from the corresponding water housing ducts -16- at an angle of approximately 90 ° thereto. The partition walls -13- at the bow end -3- of the hollow interior area -12- in which they define the air chambers -15- end at edges

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-18- that are above the normal waterline -19- in which the envelope body -2- would normally float in calm waters.

The upper wall of the upper part -10-, the front wall -7-, the intermediate wall -8- and the side walls -5- at a level above the upper edges -18- of the partition walls -13- They define a manifold -20- that interconnects the air chambers -15-. A duct -21- of air housing extends towards the stern from the intermediate wall -8- and communicates with the manifold -20- to accommodate air entering and leaving the air chambers -15- as the water level -19a- of these ascends and descends during the oscillation of the enveloping body -2- in response to the passing waves.

Conversion means comprising a self-converting turbine -22- are located in the air housing duct -21- to convert the energy of the air passing through the air-containing duct -21- into mechanical rotational energy that the air is driven in and out of the air chambers -15- in response to the variation of the water level -19a- inside the air chambers -15-. An electric generator -24- shown only in block representation, which is coupled in line with the turbine -22-, is driven by said turbine -22- to generate electricity which, in turn, is connected through an electric cable -25- (see figure 9) to a ground base station (not shown). By virtue of the fact that the turbine -22- is a self-converting turbine, the turbine -22- drives the rotor shaft -26- of the generator -24- only in one direction, regardless of the direction of the air flow through the duct -21 - of air accommodation.

A lower -27- bow-oriented part of the front wall -7- of the enclosure body -2- inclines in the direction of the stern, in general, descending to minimize the turbulence adjacent to the lower prow of the enclosure body -2-. A first stabilizer plate -28- extends in the forward direction, in general, descending from the lower inclined part -27- to control the elevation and pitching movement of the enclosure body -2- to maximize the efficiency of the conversion into usable energy of the movement of the enveloping body -2- in response to the passing waves. The lower inclined part -27- of the front wall -7- of the enclosure body -2- is inclined with respect to the vertical at an angle of approximately 45o when the enclosure body -2- is floating in calm waters with the ducts -16 - of water housing extending horizontally in a bow-to-stern direction and the air chambers -15- extending vertically in an upward direction from the water-housing ducts -16-. The first stabilizer plate -28- extends substantially perpendicularly from the lower inclined part -27- and, thus, is inclined at an angle of approximately 45 ° with the vertical when the enclosure body -2- is floating in calm waters with the substantially horizontal water housing ducts -16-. The lower inclined part -27- is located below the flotation line -19- of the enclosing body -2- when said enclosing body -2- is floating in calm waters with the water housing conduits -16- extending horizontally. The first stabilizer plate -28- extends substantially across the transverse width of the casing body -2- between the opposite side walls -5-, and extends from the lower inclined part -27- approximately midway between the upper and lower edges -23- and -36-, respectively, of the lower inclined part -27- and, in this way, the first stabilizer plate -28- extends from the enclosure -2- to a level below the waterline -19-. Four reinforcing plates -29- that extend between the first stabilizer plate -28- and the lower inclined part -27- of the enclosure body -2- reinforce the first stabilizer plate -28- to the enclosure body -2-.

A pair of second separate parallel stabilizer plates -30- extend upwardly from the bottom wall of the upper part -11- of the enclosure body -2- towards the stern end -4- thereof to stabilize the enclosure body -2 - in the waves. The second stabilizer plates extend in a general direction from bow to stern to keep the casing body -2- oriented with the bow end -3- thereof oriented towards the approaching waves.

Floating means for keeping the enclosure -2- floating include a floating reservoir -31- which is located in the lower wall of the upper part -11 - of the enclosure -2- above the water housing ducts -16- adjacent to the intermediate wall -8- and aft of the air chambers -15-. The flotation tank -31- is sealed and defines a second hollow interior area -32- for air and extends in a general direction aft of the intermediate wall -8- and ends in a wall -33- at the end of stern that, seen in plan, is substantially semicircular. In this way, the distance at which the flotation tank is prolonged -31- in the forward direction from the intermediate wall -8- is greater along the central line -34- of the enclosure body -2- which is prolonged longitudinally, that the distance at which the floating tank -31- extends in the direction of the bow along and adjacent to the respective side walls -5-. In addition to keeping the envelope body -2- floating, the floating tank -31- also controls the pitching oscillation of the envelope body -2- by virtue of the position of its center of floating. In this way, the flotation tank -31- effectively controls the relative movement of elevation and pitch of the envelope body -2- in relation to the movement of the waves and, in this way, the rise and fall of the water level - 19a- in the air chambers -15-, while the first stabilizer plate -28- acts to modify the lifting and pitching movement of the enclosure -2- but in a controlled manner in order to maximize the efficiency of the conversion of the oscillating action of the water level -19a- in the air chambers -15- in mechanical rotation energy. In this embodiment of the invention, the floating tank -31- is an airtight tank, although if desired, the second zone

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Hollow interior -32- can be filled with an expanded lightweight plastic material.

Bow ballast means comprising a bow ballast tank -35- are located at the bow end -3- of the casing body -2- to the bow of the air chambers -15-. The ballast tank -35- is adapted to accommodate ballast water pumped inwards from the ocean and the ballast in the ballast tank -35- is adjustable by varying the volume of water from it. The ballast of the ballast tank -35- in its use is adjusted in order to adjust the floating effect of the floating tank -31-, so that the wave energy converter -1 - floats in calm waters with the ducts -16- of accommodation of the water extending substantially horizontally in the direction from bow to stern and being completely submerged, and the water level -19a- in the air chambers -15- is substantially midway between the upper edges -18- of the partition walls -13- and the level of the lower wall of the upper part -11- adjacent to the air chambers -15-. Additionally, the ballast in the ballast tank -35- is adjusted in order to adjust the floating effect of the floating tank -31-, so that the openings -17- of accommodation of the aft water of the ducts -16- of water housing remain submerged in all orientations of the enclosure -2- during the pitching oscillation thereof.

The coupling means comprising a pair of separate bow mooring couplings -38- and a pair of separate stern mooring couplings -39- are arranged to couple the casing body -2- to a mooring system -40- for facilitate flotation and oscillation of the envelope body -2- in the water. Bow mooring couplings -38- are located on the front wall -7- adjacent to the respective side walls -5- at a height above the waterline -19- appropriate to local conditions and mooring couplings stern -39- are located on the second stabilizer plates -30- at a height above the waterline -19- also suitable for local conditions. The mooring lines -41- secured to the mooring couplings -38- and -39- and to the mooring buoys -42- tie the energy converter of the waves -1- in the water. The anchoring ropes -43- secured to the seafloor anchors -44- anchor the buoys of amare -42-. Consequently, the mooring system -40- is such that it allows the enveloping body -2- to rise and fall with the level of the tide, while at the same time allowing the oscillation of the enveloping body -2- by pitching and elevation in A direction from bow to stern in response to the waves that pass.

In operation, with the wave energy converter -1- moored by means of the mooring system -40- and floating in the ocean, and with the bow end -3- of the enveloping body -2- oriented towards the waves that Approximate and the electric cable -25- electrically connecting the generator -24- to the ground base station (not shown), the wave energy converter -1- is arranged to be used. As the waves pass through the enveloping body -2-, initially striking the bow end -3- of the enveloping body -2- and passing along the enveloping body -2- to the stern end -4- thereof , the enveloping body -2- oscillates. As the wave initially strikes the bow end -3- of the enclosure body -2-, said bow end -3- rises with respect to the stern end -4-, as shown in Figure 10, making that the water in the air chambers -15- is discharged through the water housing ducts -16-, resulting in a decrease in the water level -19a- in the air chambers -15- and that the air be dragged into the air chambers -15- through the air duct -21-, the air being dragged inwards through the air duct -21- turns the turbine -22- to operate the generator -24-. As the wave reaches the stern end -4- of the enveloping body -2-, the stern end -4- rises with respect to the bow end -3-, see figure 11, thus causing the water flows into the air chambers -15- through the water-housing ducts -16-, causing the water level -19a- to rise in the air chambers -15-, which in turn discharge the air through the air housing duct -21- to rotate the turbine -22- in the same way to drive the generator -24-. The next wave again raises the bow end -3- of the envelope body -2- with respect to the stern end -4- and thus the envelope body -2- oscillates with a pitching and lifting action in a bow direction to stern in response to the movement of the wave.

It has been found that the arrangement of the first stabilizer plate -28- maximizes the movement of the enclosure -2- and, in turn, the rise and fall of the water level -19a- in the air chambers -15- to convert efficiently the energy of the waves in mechanical energy of rotation.

Comparative tests were carried out in a scale model of the wave energy converter -1- according to the invention and in a wave energy converter of the prior art of dimensions and constructions identical to the wave energy converter according to the invention, with the exception that the prior art wave energy converter was manufactured without a first stabilizer plate and without a ballast tank or any other form of ballast. The tests on the two scale models were carried out in a wave generation tank that generates waves for a period of time in the range of 5.5 seconds to 13 seconds during time intervals of approximately 5 minutes for each period of wave. The waves were of constant height for all periods tested. Both scale models were moored in the wave generation tank and the electrical power output of the respective scale models was measured in kilowatts and averaged over the 5 minute residence time of the respective wave periods.

It is anticipated that a real-scale wave energy converter according to the invention will be approximately 25 meters long from the bow end -3- to the stern end -4- and a transverse width from a

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side wall -5- to the other of approximately 12.5 meters with three air chambers -15- and a corresponding number of water housing ducts -16-, that is, three water housing ducts -16-. Although it is envisioned that a real-scale model of the wave energy converter according to the invention can have a length of up to 42 meters and a width of up to 21 meters, and said wave energy converter can be provided with up to six cameras of air and six water housing ducts. It is expected that one to three water housing ducts -21- separated equidistantly will extend from the intermediate wall -8- communicating with the manifold -20- of the full-scale models. The scale models of the wave energy converter according to the invention and the wave energy converter of the prior art had a length of approximately 2.5 meters and a width of approximately 1.05 meters, and each of them It was equipped with three air chambers -15- and three water housing ducts -16-. A single water housing duct -21- was arranged from the manifold -20- of each scale model. The models were scaled based on Froude's scaling law for free surface hydrodynamic models, which requires that the time scales be equivalent to the square root of the length of the scales.

Referring to Figure 12 below, the graphs representing the average power output in kilowatts represented on the Y axis are shown with respect to the time period in seconds of the waves represented on the X axis. Graph A of Figure 12 represents the measured average power output generated by the wave energy converter according to the invention during the time intervals in which the wave energy converter was subjected to waves of the respective different time periods. Graph B represents the measured average power output generated by the wave energy converter of the prior art during the time intervals in which the wave energy converter of the prior art was subjected to waves of the respective periods of different time. As it is observed, for all periods of wave time the average power output of the wave energy converter according to the invention exceeds the average power output generated by the wave energy converter of the prior art. The difference in the average power output generated by the wave energy converter according to the invention over that generated by the wave energy converter of the prior art had a peak in a wave period of 8.5 seconds, which is the resonance period for both scale models, in which the average power output generated by the wave energy converter according to the invention was almost 60% greater than that generated by the wave energy converter of the prior art. In a wave period of 8.5 seconds, the wave energy converter according to the invention generated an average power output of approximately 475 kW, while the prior art wave energy converter generated a power output. average of approximately 300 kW. Even in the smallest difference, which occurred in a wave period of 13 seconds, the wave energy converter according to the invention generated an average power output of approximately 210 kW that was approximately 40% higher than the average power output 150 kW corresponding generated by the wave energy converter of the prior art.

In this way, for all wave periods between 5.5 seconds and 13 seconds, the wave energy converter according to the invention generated an average power output significantly greater than that of the prior art wave energy converter. . It should be noted that the resonance period is scaled as the square root of the length of the scale used to make the model.

A quarter-scale model of the wave energy converter according to the invention was tested in Galway Bay for an eight-month period from December 2006 to August 2007, which confirms the results achieved by the model tests a scale carried out with the wave energy converter according to the invention in the wave generation tank. The scale model tested at Galway Bay was 12.5 meters long by 6.25 meters wide with three chambers -15- and three water-housing ducts -16-. A single air housing duct -21- was arranged from the manifold -20- in the intermediate wall -8-. The average power outputs measured during the Galway Bay test were compared with the measured average power outputs of the scale model of the wave energy converter according to the invention in the tests in the wave generation tank in corresponding combinations at the height of the wave and the period of wave scaled according to the Froude scale law. The average power outputs of the quarter-scale model tested in Galway Bay compared carefully with the measurements of the scale model of the wave energy converter according to the invention tested in the wave generation tank, confirmed, in this way , the results obtained from the wave energy converter according to the invention tested in the wave generation tank.

Although the wave energy converter has been described as comprising three air chambers and the corresponding three water housing ducts, the converter can be provided with any number of air chambers and any number of water housing ducts from one onwards. Additionally, even though the converter has been described as comprising a water housing conduit corresponding to each air chamber, in certain cases, it is envisioned that a series of water housing conduits can communicate with a single air chamber, and it is also foreseen that a single water housing conduit can be arranged to communicate with a series of air chambers. It goes without saying that an air duct can also be provided for each air chamber or for groups of air chambers and, in that case, a turbine and an electric generator would be arranged in each air duct. Additionally, it is planned to arrange any number of air housing ducts from the collector and,

In certain cases, it is envisaged that several air housing ducts may converge into a single duct that would house the turbine or other suitable conversion means.

Although the energy conversion means for converting the energy of the air that passes through the air accommodation duct 5 into rotational mechanical energy has been described as comprising a particular type of turbine, any other turbine or other suitable means of conversion. For example, it is envisioned that a Wells turbine or a drive turbine can be used and even though it is desirable that the turbine be a self-converting turbine, it is not essential. For example, in cases where the turbine is not a self-converting turbine, a suitable system of ducts and valves can be arranged to direct the air in a single direction through the turbine.

It is envisioned that, in certain cases, the lower inclined part of the bow end of the wrapping body can be arranged with a rounded lower portion, which would also minimize the turbulence adjacent to the lower bow end of the wrapping body.

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Even when a single air housing duct that extends from the collector has been described, it is envisioned that a series of air accommodation ducts extending from the collector can be provided and, it goes without saying that it will be appreciated that they could have a turbine and a generator in each air housing duct.

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It is also envisioned that even if the ballast means have been described as comprising a ballast tank for receiving water ballast, it is envisaged that any other suitable ballast means may be provided, for example, in certain cases, the possibility is provided of receiving one or more ballast weights and even when it is desirable to provide a ballast adjustment, this is not essential, and in certain cases, it is envisioned that non-adjustable ballast means 25 can be provided.

It will also be appreciated that even though the floating means have been described as being of a specific shape and configuration, floating means of any other suitable shape and configuration can be arranged.

Claims (13)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. Floating wave energy converter, to convert the wave energy into electricity, the wave energy converter comprising an enveloping body (2) adapted to oscillate in response to the movement of the waves and extending between a bow end (3) and a stern end (4) with the bow end (3) thereof adapted to face the waves when in operation, a bow-oriented bottom part (27) of the enclosure body (2 ) adjacent to the bow end (3) thereof inclined in the stern direction, generally downward, an air chamber (15) formed in the housing (2) adjacent to the bow end (3) thereof, a duct of Water housing (16) formed in the housing (2) and extending aft from the air chamber (15) to accommodate water entering and leaving the air chamber (15) as the housing (2) ) oscillates in response to wave movement to vary the level of water a in the air chamber (15), terminating the water housing conduit (16) in a water housing opening (17) located aft of the air chamber (15) at the stern end (4) of the enclosure body (2), an air housing duct (21) for accommodating air entering and leaving the air chamber (15) in response to the variation of the water level thereof, conversion means (22) for converting the energy of the driven air through the air housing duct (21) in response to the variation of the water level in the air chamber (15) in mechanical rotation energy, characterized in that a first stabilizing plate (28) it extends below the floating line (19) of the enclosing body (2) in a forward direction, generally descending from the lower forward-facing part (27) of the enclosing body (2) at a certain angle with respect to to it adjacent to the bow end (3) of the enclosure body (2) to control the mov pitch and elevation of the envelope body (2) to maximize the efficiency of the conversion of the movement of the envelope body (2) in the water into usable energy. 2. Floating wave energy converter, according to claim 1, characterized in that the first stabilizer plate (28) extends from the housing (2) to a level below the floating line (19). 3. Floating wave energy converter, according to claim 1 or 2, characterized in that the first stabilizer plate (28) extends, in general, transversely to the bow-to-stern direction of the enclosure (2) . 4. Floating wave energy converter, according to any of the preceding claims, characterized in that the first stabilizer plate (28) extends from the bow end (3) of the enclosure body (2) at an angle with respect to the vertical in a range of 30o to 60o when the enclosure body (2) is floating with the water housing conduit (21) located substantially horizontal. 5. Floating wave energy converter, according to any of the preceding claims, characterized in that the bottom-facing part (27) of the enclosure body (2) adjacent to the bow end (3) thereof bends in a Direction towards the bow, in general, descending at an angle of inclination with respect to the vertical one in a range of 30o to 60o when the enclosure (2) is floating with the water housing conduit (21) located substantially horizontal. 6. Floating wave energy converter, according to any of the preceding claims, characterized in that the bow-oriented inclined part (27) of the housing (2) is located below the floating line (19). 7. Floating wave energy converter, according to any one of the preceding claims, characterized in that the first stabilizer plate (28) extends from the bow-oriented bottom part (27) of the enclosure body (2) at an angle of approximately 90o with respect to it. 8. Floating wave energy converter, according to any of the preceding claims, characterized in that the first stabilizer plate (28) is reinforced, at least, by a reinforcement plate (29) extending between the first stabilizer plate (28) and the enveloping body (2). 9. Floating wave energy converter, according to any one of the preceding claims, characterized in that ballast means are arranged at the bow (35) adjacent to the bow end (3) of the wrapping body (2) and at the bow of the air chamber (15) to stabilize the enclosure body (2), the bow ballast means (35) being located above the level of the first stabilizer plate (28). 10. Floating wave energy converter, according to any of the preceding claims, characterized in that at least a second stabilizer plate (30) extends from the casing (2) aligned in a direction, in general, of bow aft and reacts to the movement of the wave passing through the enveloping body (2) to keep the enveloping body (2) oriented with the bow end (3) thereof oriented towards the waves. 11. Floating wave energy converter, according to any of the preceding claims, characterized in that the air chamber (15) extends in an upward direction from the water housing conduit (16) adjacent to the bow end of the same. 12. Floating wave energy converter, according to any one of the preceding claims, characterized in that some floating means (31) are located adjacent and aft of the air chamber (15) and above the water housing duct (16) to keep the enveloping body (2) floating on water. 5 13. Floating wave energy converter, according to any one of the preceding claims, characterized in that the conversion means (22) for converting the air that is driven through the air housing duct (21) into rotational movement they comprise a turbine (22).