Plant for the Recovery of Energy from Waves in Water

P FOR T OE RECOVERY OF ENERGY FROM WAVES IN WATER Background of the invention The invention relates to a plant for recovering energy from waves in motion in the water surface and as presented in the preamble of claim I. A known. plant of this type is described in SE publication no. 443,026 publìshed on 86-02-10. In principle, this known plant comprises a se idomed, bell-like construction floating in the water and taking water in at the top. The |5 water is guided to a reception pipe which guides the water to a turbine driving a generator for electrical energy. The known construction also provides the possibility of applying n elongated pipe extending parallel with the water surface and having the same diameter throughout its length, which pipe ends in a diffuser for water outlet. This plant is arranged to float partially submerged and the waves are caught by an upwardly-extending tower with openings in all directions allowing the water in the waves to run trough the openings irrespective of the direction of the waves in relation to the plant. It is an unfavourable construction in respect of energy, as only a smal! part of the waves are caught; consequently, only a part of the wave energy is recovered. Besides, this construction has not considered the principle that water seeks its own level, as the diffuser of the plant is placed in direct continuation of the horisontal pipe. A wave passing perpendicularly to this cons:ruction wi!l stop most of the outlet. • -r • o.,- 2 22485 S,,--ary oE the Invention According to the invention, there is provided a plant for recovering energy froc, waves in motion on a water surface, comprising a float (2) and mn anchor receiving attachment on the float. The float (2) includes at leas: one buoyancy ch..ber below the water surface, a reception pipe (8) positioned below the water surface and having at least one discharge port, a generally wedge-shaped array of funnels (4) with each funnel having an inlet end proximate the water surface positionable so as to face incoming waves, a ramp (3) positioned to guide water towards the array of funnels, and an energy converting engine (9) located in the reception pipe (8) operative to convert wave energy into electrical energy. The fur_nels (4) fo.-m rows of one or more funnels stacked in a step-like manner such that the inlet ends of the funnels in successively higher rows are further away from the wave reception side of the float, each funnel having an outlet end coupled fo the reception pipe (8). Furthermore, the funnels ex,end in a curved manner with the inlet ends substantially aligned with an expected angle of water from a wave and a cross section of each funnel is gradually reduced in a direction towards the reception pipe (8) with an angle of each funnel gradually increasing towards vertical. Additionally, the anchor receiving attachment is located in a position substantially aligned in a plane through a center of the wedge-shaped array of funnels so that when anchored, the anchored array of funnels are held facing the inco=,ing waves. In operation, the plant provides the advantage of concentrating and converting both the potential and kinetic D a energy of waves into electrical energy. The plant further provides the advantage of a structure which guides captured wave water to n energy converting engine without applying particular moving parts. The design of the plant also has the advantage that large amounts of water from a wave are collected so as to improve the amount of energy recovered. Moreover, the wedge-shaped design of the array of funnels aids in aligning the water reception side of the float with an oncoming wave and.assists in evenly distributing the I0 admission of water into the funnels. In an alternative embodiment, the plant includes a mooring with an anchor chain (7), the anchor chain having such a length that when it is attached to the anchor receiving attachment and the anchor, the anchor chain forms an oblique angle of at least 60" in relation to a horizontal surface of the water. This embodiment provides the added advantage ha the plar.t will be less susceptible to riding the waves so as to improve the opportunity for waves to break over the plant proximate the wave receiving side. In another embodiment, the array of funnels (4) is formed from a number of shells or plates (12) extending in a cu_--veæ manner from the inlet ends to the outlet ends of the fur_nels, which aæv ntageously provides a simple yet effective structure and improves the velocity at which water reaches the energy, converting engine. The array of funnels (4) may have vertical partition plates (20) and the plates (12) ay have substantially curved contours proximate the outlet ends of the Runnels so as to further improve the velocity at which water reaches the energy converting engine. -,-w In another embodiment, the funnels forming the lower rows of the array of funnels may include one or more flap valves coupled to an inner wall of each funnel. The flap valves provide the advantage of reducing the amount of back flow of water within the funnels. The number of flap valves in each such funnel may be two, with one flap valve located near the inlet end, and the other flap valve.located near the outlet end. This arrangement provides for the automatic regulation of water admission to the reception pipe (8) thereby regala:ing the flow of water to the energy converting engine. In another embodiment, a plurality of funnels in a rearward portion of the array opposite the wave reception side are substantially vertical. Each such funnel ìncludes an elongated reservoir chamber (21) within the funnel proximate the inlet end and having an open end in a region near the outlet end. The reservoir chambers (21) each have at least one air escape opening (22) proximate a top region of the chamber. This embodiment provides improved regulation tc the admission of water to the reception pipe (8), even if there is a great distance between the waves. The rese_--voir chamber (21) may have a cross-section converging proximate the open end to improve the velocity of waler returning from the chamber. In another embodiment there is included a shield (15) extending substantially vertically above a rear-most row of the array of tunnels oppositethe wave reception side, having the advantage that water which would otherwise pass over the plant is directed to the funnels. In another embodiment, the buoyancy chamber is an air ch-=mber (16) which provides a simple yet effective design fcr maintaining the buoyancy of the float (2). In another embodiment, the float includes an outlet chamber (17) located adjacent the reception pipe (8) and proximate the discharge ports, to improve the regulation and discharge of water from the reception pipe (8). In yet another embodiment, the ramp (3) is wedgeshaped to further improve the distribution of water entering the funnels. Brief Description of thê Drawings The novel features believed characteristic of the invention are set forth in the appended claims." ," ne invention itself, however, as well as other features and advantages thereof, will be best understood by reference to the detailed description which follows, read in conjunction with the accompanying drawings, wherein: ig. 1 is a perspective view of the plant; fig. 2 is a side of the plant; fig. 3 is a plane part section III-III in fig. i; í.2 PCI'IDKgl/oe329 wo,31 2 1 2 2 1 8 3 4 fig. 4 is a plane pari section IV-IV in fig. i, end fig. 5 is s plane section V-V in fig. i. Descríption of the embodiment example Fig. i is an inclined front view of the plant in general eccordlng 1o the invention and in order to look into the construction its right side has been removed. The plant comprises a float 2, a part of which As above the water surface 25 while the test is below the surfaoe. The plant is anchored to an anchor by means of an anchor table or en anchor chain 7 which will tarer be explained in more detail. The plant is substantially wedge-shaped and %ha anchor cable is attached close %0 the point, so thai %he plant will straighten oui and thus will always turn ifs point towards the incoming waves. In the end where the wave hits the plant first, i.e. ai the pointed end of the plant, it comprises a ramp 3 extending down below the surface in an inclined manner allowing incoming waves fo roll up the ramp and over the construction. Besides, the float 2 is roof-ridge-formed with the roof ridge 23 in the longitudinal direction. The plant is kept floating by a number of air chambers 15 being adjusted in such a manner that substantially only the reception funnels 4 and %ha shield 15 are above the water surface, cf. fig. 1. When the waves ro11 into and up over the construction, the funnels 4 will be filled w±th water which al great speed is guided down into a reception pipe 8 through the narrowed course of the funnels, which plpe 8 at both ends is provided with a turbine with an energy converting engine 9, e.g. for generating electrical energy, which through a cable {not shown) is conducted to an ordinary power supply system, possibly via a switch or converter station. WO 93/093#7 PUTIDK91/oe329 The stern 5 of %he construction will usually be below the water surface. The funnels 4 are formed of curved or bent shells or plates 12 and side plates 20 which addltlonally make up partition plates, so %hat the funnels 4 are arranged in sections. The arrangement of l e funnels 4 is moreover srrow-shaped with the point directed towards the anchor cable 7 and %ha roof ridge 23, cf. fig. I. Behind the funnels 4 is placed an oblong shield 15 to throw a par% of the crest of the wave, wh!ch would otherwise fol1 over %he construction, beck towards and down into the funnels. Due fo %he fact %hat %he construction is wedge-shaped with the roof ridge 23 and ue to. the arrangement of the funnels, an incoming wave will be divided into wo and distribute Itself over the two sides of the plan%, as %he funnels are filled successively w th water. The utilization of the amount of water in a wave is hereby increased resulting in a continuous supply of water %0 the turbine 9. The shield is highest ai the middle and may be designed in such a manner that the curvature increases towards each side. The reception pipe 8 is actually made up of to pipes extending from the middle under the roof ridge 23. The arrangement of the pipes 8 is also arrow-shaped an forms a more acute angle than does the arrow-shaped arrangement of the funnels 4. At each side the plant is provided with a side chamber I0. The side chamber is partially f111ed with alr and through the turbine 9 the reception pipe 8 opens mi each sÆde into the chamber I0, which wlll be explained in more detail with ..... O'93/0934 7 POEtDK91 f00329 refez ence to fig. 5 of the drawing. l0 Fig. 2 shows in more detail how the plant according to the invention floats in the water surface 27 and how a wave 26 passes the plant. An anchor 6 secures the plant i by means of an anchor chain or an anchor cable 7, which probably at the very top ai the construction itself is subdivided, e.g. tripartited. The anchor chain should have such a length Lhat at high water the chain forms an angle of at least 60" in relation to the horizontal plane or an angle V of 30" in relation to the vertical plane as shown in the drawing. The plant is hereby prevented rom riding the waves, and maximum energy recovery is achieved. Fig. 3 shows a vertical plane part section through the outer funnels. The funnels are formed of shells or plates 12 extending for%-ard towards the incoming wave. BeTween the shells gaps 13 with narrowed down cross sections are fo.--med in order to increase the velocity of the water. Some of the shells, preferably those in The lower position, are provided with valves 18 which wil close if the water tries to flow back an out through the gaps 13. The valve flaps 18 may be made of reinforced rubber or the like and òesigned in such a manner that they are self-closing without mechanica£ maneuvering members. The other end of the passages may also comprise valve flaps 19 preventing water from the more vertically positioned gaps from flowing out through the Forward extending gaps. These valves are also valve flags of reinforced rubber or the like without mechanical manoeuvring members. The vertically positioned gaps or water chambers may be designed having damming cr reservoir chambers 2!, in which the water can be dammed up before running "ånto the reception pipe B later. AS an example the reservoir chambers 21 have air escape openings 22 et the op of tre chambers allowing poEjF... 0 93109347 sable air in the chambers to be pressed out this way. To ensure correct admission of water to the inlet pipe 14 of the reception pipe 8 a pivoting guide plate 24 may be placed here, so that water pressure at the one side of the guide plate blocks the inlet from the opposite side. The water is moreover guided tangentially through the inlet 14 into the reception pipe 8 in such a manner that the water in the reception pipe flows along a helical llne towards the turbine 9. Fig. 4 shows a plane part section in the reception funnels close fo the middle of the plant. It appears that the reOEeption funnels at the middle of the ¢onstructlon have no reservoir chambers and that the reception pipe 8 is moreover positioned further ahead due to the fact that the pipe 8 extends towards the rear in an inclined manner viewed from the middle of the construction. Fig. 5 shows how he water outlet from the turbine 9 takes place in the side chamber 10. The side chamber comprises an outlet chamber17 partially filled wl%h air, where the water from the reception pipe is guided through the turbine 9 out into the chamber and further out into the sea. When the waves roll over t/le construction and the water is guided down through the funnels, some air will be carried along which will collect et the top of the ourlet chamber 17. The outlet chamber 17 has sulteble means ensuring that the air leaves the chamber in a suitable manner so that a desired liquid leva1 is maintained. AIl parts of the plant are made of strong materials, Dreratably as a welded steel construction strong enough to stand the tremendous strain %ha whole construction is exposed to. Besides, all parts are made of corrosion resistant materials. ...... WO 93109347 PCTIDK91100329 The embodiment shown in the drawing and explained in the description being only an example, it is et any rate a preferred exemple of how a plant according to the invention can be designed. It will be obvious fo a person skilled in the art to design the plant in many different ways without deviating from the% which is stated in he below patent claims. It will be obvious fo e person skilled in the art that the Bize ànd strength etoE. of the plant depends on where the plant is intended to be used, the maximum wave heights of the place in question end the average wave frequency. If will thus be possible within the scope of the invention to produce plants varying greatly An size. I CLAIM." I. A plant for recovering energy from waves in motion on a water surface, said plant comprising: (a) a float(2) having surface, (i) at least one buoyancy chamber below the water (ii) a reception pipe (8) positioned below the surface of the water and having at least one discharge port to permit the discharge of water from said reception pipe, (ili)a generally wedge-shaped array of funnels (4) at a wave reception side of said float each funnel having an inlet end proximate the water surface positionabie so as to face incoming waves, said funnels (4) forming rows of one or more funnels stacked in a step-like manner such that the inlet ends of the funnels in successively higher rows are further away fro said wave reception side, and said f Ln/ els (4) each having an outlet end coupled to said reception pipe (8), (iv) a ramp (3) positioned to guide water in a wave towards said array of funnels (4), (v) an energy converting engine (9) located in said reception pipe (8) operative to convert wave energy to electrical energy, wherein said funnels extend in a curved maimer with the inlet ends substantially aligned with an expected entrance angle of water from a wave and a cross-section of each funnel gradually reduced in a direction