GB2528528A - A floating structure and floating system comprising a plurality of devices for electrical energy by water waves - Google Patents

Abstract

A submerged platform may have at least two floats S1, S2 and at least two electrical generators VR1, VR2, VR3. The platform may have inertia reservoirs WR to steady it. An electrical generator (VR3, fig 13b) may have a water reservoir (5a, fig 13b) and a float (5, fig 13b) to generate electricity from the upward and downward movement of a wave. Electrical generators VR may have a stationary part (LK1, fig 5) fixed to the platform, and a relatively movable part (LK2, fig 5) attached to a float (5, fig 5). The platform, which may be more dense than seawater, may be submerged in a deep sea position, where the hydrostatic pressure from waves formed at the water surface varies insignificantly with time. The platform may be reinforced with scaffolding.

Description

A floating structure and floating system comprising a plurality of devices for electrical energy by water waves

1. Background

[0001] There are already many inventions based on energy generation by water movement. The existing ideas about energy generation by the movement of sea water envisage the drawing of power from either the vertical or the horizontal movement of water masses corresponding to the propagation of the waves on sea surface, c.f. DE-A-4338103; US-A-4,110,630; WO-A-02/103881; CN201099347Y.

[0002] Furthermore, Japanese Patent Application JP55160967 discloses a floating device consisting of a first, easily movable part connected to a float, which under the influence of water waves experiences a relative movement relative to a second heavier part floating almost stationary in the water. By this relative movement, an electric generator is operated, which converts the mechanical energy into electricity. Different variations have since then been published, however, in none of these publications details are given of devices which would be able to deliver a power of several kW.

[0003] In 2009 the company Ocean Power Technologies "Power Buoy" presented devices with a stationary part, which were able to produce electrical energy in the range of several kW.

[0004] In our International Patent Application W02011 / 120497 we have shown how the differences in hydrostatic fluctuations at the surface of the water compared to minimal pressure fluctuations in deeper water levels can be exploited to allow almost complete wave energy by energy generating devices. The basic idea behind it was that a very high inertial mass that floats in water and of which the center of gravity undergoes minimal hydrostatic pressure fluctuations could substitute the stationary part of an energy producing device. Two different species have been described as to how this goal can be achieved.

[0005] In 2012, the company Ocean Power Technologies announced a 45kw device with a floating inertial part that weighs several hundred tons presented (Link: http://www.oceanpowertechnologies.com/PDFJPB150 08292012 GFL.pdf published on 19/09. 2012).

[0006] Recently we have presented in a German patent application (Reference: 10 2014 003 228.0) a device in which, instead of a floating inertial part weighing several tons, a considerably lighter device unit is used, which floats inside a tube and which generates -in view of a hydrostatic effect -the necessary counter-force to that of the buoyancy of the movable member, so that an electric generator which is coupled to this device and to the moving part, can produce electrical energy. Thus, the ratio of the available power to the weight of the entire device could be increased.

2. The object of the invention [0007] The object of the present invention lies in the utilization of hydrostatic effects for the development of complete systems which contain one or more energy producing devices in which the power / weight ratio can be further increased.

[0008] In a first aspect, a new way is described so that the apparatus disclosed in German Patent Application (Reference: DE 10 2014 003 228.0) is not only functional to deliver electric energy during a half period of the water wave (i.e. when a buoy is lifted upward by a swelling wave), but during the entire period (i.e. also during the downward movement of the buoy). In this way we can further reduce the dimensions of the less mobile "inertial component" interacting with the more mobile buoyant component.

[0009] In another system, a novel way is proposed to stabilize the "inertial component" of the electrical generating device, which should not be influenced by the vertical movement of water waves, within a narrow range of vertical movement in a deep area of the sea. It is further contemplated to produce useful energy by designing a quasi-stationary part of significant lateral dimensions which is capable to float at certain depth and to which a variety of energy-generating units can be connected, each of those units having a floating, movable part whose periodic vertical motions can be used to drive power generators.

[0010] By providing a common "inertial component" stabilized in water as mentioned above, on which several energy generating units can be mounted, the mass fraction per power generating unit can be kept significantly smaller than in the case in which a single "inertial component" acts dynamically s as the counterpart of a mobile part as explained in the International Patent Application W02011 / 120497 and demonstrated in the energy system of Ocean Power Technologies disclosed in 2012.

3. The new principle [0011] The relevant principle described in the German patent application filed under the number 102014 003 228.0 is briefly explained with reference to figure 1. The following reference numerals are used to explain the underlying hydrostatic principle. The right side of figure 1 diagrammatically shows the behavior of a device according to the parallel patent application, in a wave trough, which nearly corresponds to the behavior at rest, i.e. in quiescent waters. The left side of figure 1 represents the behavior of the device at the wave crest.

Reference numeral list VE1: first device unit (easily movable part, fitted with a float) VE2: second device unit ("immobile" part) OS: Internal cross-section of VE1 D: maximum travel of VE1 under wave action D: maximum travel distance of VE2 under wave action BE1, BE2: areas of VE1 and VE2 in which an electric generator is coupled to the respective device units EC: diagrammatic illustration of an electric or electromagnetic current generator VR: general term of electrical energy generating devices of types VR1, VR2 and VR3 LT: elongated (long-shaped) support member PT: platform-shaped carrier element (platform-shaped support mem ber) VG: scaffolding for fastening device units VR, especially for support elements that are intended to be submerged at a depth greater than S m (reinforcement framework for LT, PT) TRM: optional towers on the carrier elements (LT, PT) Ml, M2: modules for the compilation of extended, elongated or platform-shaped support members Cl, C2: coupling elements (z. B. spherically or bi-axially) for connection of the modules Ml, M2 CS: bi-axially steerable or articulated coupling element ZS: link hawser PF: buffer / shock absorber SF: directed lateral bars (wings), transverse to the long axis of modules Ml, M2 ME: directed arranged in the middle cross-member (center panels), transversely to the long axis of modules Ml, M2 MTR: small towers for mounting tension cables SL serving as mechanical support of central wing MF SL: pull rope for framework elements 51, S2: floats for hanging the carrier (support) elements LT, PT Kl: component of the device VR which is associated with a support element K2: mobile component of the device VR VR1: device which operates unidirectionally in the compression mode VR2: device operating in tensile mode unidirectionally VR3: device which is bidirectional operating both during the formation of a wave crest as well as during the formation of a wave trough LK1: element fixed to a support LT, PT, along which the mobile element LK2 can glide LKZ: elongated, mobile, sliding element of a device VR WS: floating body of the component K2 ESC: optional water-filled area of the floating bodyWS SL1: connection cable between the components EC and WS for a device of the type VR2 5L2: connection cable between generator EG and coupling elements of the generator EG in certain constructions of the type VR1, VR2, VR3 WR: water reservoir, acting as inertial mass enhancer of the support elements LT, PT GW: optional weights, with an average density that is significantly higher than the density of water (containing e.g. as cement or metal blocks) AX: axis of rotation that can be attached to VR devices, so that they are not affected by rocking motion of the support element LT, PT AL: rope suspension that connects floats 51, S2 with the support elements LT, PT WF: designation of a wave-front 1: water level (or water line) on the surface of a wave 2: diagrammatic profile views of the hydrostatic pressure variation in a deep sea region 3: elongated hollow body of VE1 4: wall portion of VE2 5: floating body connected to the hollow body 3 of VE1 6: closed voluminous regions (compartment) of VE2, especially water reservoir provided with (not shown) openings for inlet / outlet water 7: cavity to adjust the average density of VE1, so that in the idle state, a small area of the entire area, consisting of the voluminous compartments 6 and 7 protrudes outside of the water level 8: plate on which device components can be mounted 9: equipment room 10, 11: diagrammatic representation of a transmission mechanism (piston, transmission apparatus) for driving a generator EG (e.g. a dynamo [C) 12: ballast lowering the center of mass of the entire device for preventing extreme inclinations 13: fixings for ballast 12 to VE2 14: water level at rest 15: waterline illustrating the potential minimal fluctuation of the water level 14 inside the hollow body 3 when VE1 is at maximum height; waterline 15 may lie just above or just below water level 14 16: steerable anchoring element for the component Ki of a device VR 17: winders for ropes SL1, SL2 18: rewind for ropes ai, SL2 19: openings for filling the water reservoir WR (optionally closeable) 20: sliding element 21: holder (support) 22: piston for hydraulic arrangement 23: operating fluid for the hydraulic arrangement of figure 4 24: valve which opens under pressure in the direction of arrow 25: rotor, driven by the flow of fluid 23, which is coupled to the rotor of the generator EG 26: tube 27: large valve that opens under pressure in the direction of arrow [0012] According to the German patent application 102014003228.0 the mobile member (yEa) of the device comprises a long hollow body (3) whose length is so large that the lower open end of the hollow body is always at a depth of the sea, at which the lateral variations of the hydrostatic pressure are always very low. This has the consequence that regardless of the depth in which the lower open end of the hollow body (3) is located, the hydrostatic pressure at this end, which is equal to the atmospheric pressure plus p g h (where: p = water density, g = gravitational acceleration, h = the height of the water column within the hollow body (3)) Is always equal to the average pressure at the corresponding sea depth. Therefore, the water level within the hollow body can experience temporal fluctuations only if corresponding pressure fluctuations at a certain depth of the sea also occur. Since these pressure fluctuations are low, the water level within the hollow body hardly changes compared to the height variations of the surrounding waves. As with almost all devices of the same class, a force that is able to drive an electrical generator is created between the movable and stationary device parts. This force tends to pull the "immobile" part of the device out of the water as a wave builds up.

[0013] The diameter of the "immobile" part (VE2) is chosen sufficiently large so that if this part is pulled up by a distance (d), this distance corresponds only to a small fraction of the wave height corresponding to (e.g. 0.75 m for a wave height of 4 m); the displaced volume of water equal gives rise to a force that corresponds to the weight of water having that volume (according to the principle of Archimedes), which counteracts the buoyancy force of the moving part (VE1). This hydrostatic "recoil effect" is as effective as that of the dynamic inertial effect, which could otherwise be achieved by an inertial mass of more than 100 tons.

4. Detailed Description of the Invention

[0014] The present invention relates to a device according to claim 1 for the production of electrical energy by water wave motion including a first device unit (yEa) and a second device unit (VE2), wherein -the first device unit (yE 1) a longitudinally extending preferably tubular containing hollow body (3) with its end determined to be dipped in water being open and having fixed at least one float (5) on the outer wall of the hollow body (3), so that the hollow body (3) can follow the upward / downward movement of a water wave; -the second device unit (VE2) is designed such that it can slide along the interior of the first device unit (yEa), but slightly spaced from the inner wall of the hollow body (3) so that water can flow through a there between existing intermediate space; -at a first portion (BE1) of the first device unit (VE1) and a second portion (BE2) of the second device unit (VE2) is at least one electric generator (EC) coupled electro-mechanically or electro-magnetically, so that it can generate electrical energy by means of the relative slide movement of the second device unit (VE2) along the inner walls of the first device unit (VE1); -the second device unit (VE2) has a third voluminous portion (7) having a lower density than the density of water and is provided with a sealed voluminous portion (6), which may be a water reservoir having inlet and outlet openings, wherein the average density of the sealed voluminous portion, or water reservoir (6) is almost the same as the density of water and the total volume of the sealed, voluminous portion (6), is at least half as much as the total volume of the float (4) and in that the internal cross section "OS" the first device unit (yE 1) along the region in which the closed, voluminous regions (6, 7) of the second device unit (VE2) slide is such that the product of the cross section "05" calculated in square meters is 12 times) or 8 times, or 6) preferably 4 times or 2 times, or even 1 times greater than the total volume of the floating body (4) calculated in cubic meters, and -the average density of the second device unit (VE2) is such that at rest in water, the voluminous portions (6, 7) of this device unit (VE2) protrude at least 0.3 m, preferably at least 0.6 m and even more preferably at least 09 m above the water line so that by dipping a substantial part of the portion of the second device unit (VE2 protruding above the water line at rest, via the coupling to the at least one electrical generation (EC) an upward force against the first device unit (yE 1) acts in such a way that under the influence of water waves, the at least one electric generator (EC) generates electric energy during both the upward and during the downward movement of the first device unit (VE1).

[0015] The invention also relates to a system for generating electrical energy by wave motion of water containing -an elongate support member (LT) or a platform-shaped carrier element (PT) whose average density is higher than the density of sea water, which may be reinforced by means of a scaffolding (VG) against bending deformation, wherein the elongated support member (LT) or platform-shaped carrier element (PT) is intended to be sunk into a deep sea position, where the hydrostatic pressure exercised by sea waves formed at water surface varies insignificantly with time, -at least two floats (51, S2) connected with the elongate support member ( LT) or with the platform-shaped carrier element (PT), so that this support member or carrier element (LI, PT) may be suspended positioned in a given sea depth by the buoyancy of the floats (Si, S2) floating at water surface, and -at least two independent devices (VR) for driving an electric generator (EG), wherein each device (VR) is fixedly connected to the supporting member or carrier element (LT, PT) at a predetermined position, and wherein each device (VR) contains a solid component (Ki) associated with the support member or carrier element (LT, PT) to which is firmly connected and also a movable component (C2) that is firmly connected with its own water swimmer (WS), wherein each device (VR) is coupled to and drives an electric generator (EG) as a result of the relative motion between the solid component (K1) and the movable component (C2), which is caused by the vertical movement of the water float (WS) under the influence of water waves, and -optionally one or more water reservoir(s) (WR) attached to the said elongated support member (LT) and to the platform-shaped carrier element (PT), so that the inertial mass of the carrier element (LI, PT) is considerably increased.

4.1 Figures: [0016] Figure 1 diagrammatically shows the working principle of the invention disclosed in the German patent application filed under the number 102014003 228.0 [0017] Figure 2 diagrammatically shows an embodiment of the device according to the present invention [0018] Figures 3a, b show electric power generating devices that can be used in a system according to the present invention, which can be driven unidirectionally in either compression or in traction mode or bi-di rectionally [0019] Figure 4 illustrates the principle of operation of an energy-generating device for a system according to the present invention, which can be driven hydraulically in the compression mode [0020] Figures 5 and 6 show devices that can be mounted on the support member of a system according to the present invention and such a system carrying a plurality of power generating units [0021] Figure 7 shows a variant of the system according to the present invention [0022] Figure 8 illustrates the modular structure of elongated support members LT; a module provided with transverse, longitudinal frames (side wings SF), to which are connected a variety of floats [0023] Figure 9 shows a carrier element LT with an extra-long, transverse frame (center wing MF), whose length is dimensioned substantially longer than the length of a water wave in the intended area of operation [0024] Figures 10, 11, 12a, 12b diagrammatically illustrate examples of the arrangement of groups of individual power generating units onto elongated or platform-shaped carrier elements of systems according to the present invention [0025] Figures 13a, 13b, 13c elucidate Embodiment 1 [0026] Figure 14 elucidates the benefits of the present system [0027] Figure 15 illustrates the principle of coupling a plurality of devices (VR) on a single electric generator (EG) 4.2 Description of an embodiment of the device according to the invention a [0028] A disadvantage of the device whose operation has been briefly explained by reference to figure 1 is that the total potential energy available through the swelling of water, is usefully exploited only during the half-period of wave crest formation. During this phase, the device unit (VE2) emerges gradually above waterline ( 14) In the interior of the hollow body ( 3) and the weight corresponding to the volume of water equaling the freshly emerging volume of (VE2) corresponds to the force generated by the upward movement of the float ( 5) together with the hollow body ( 3). This force interaction is used to drive the electric generator EG. During the phase in which the wave retrieves, there is no significant interactive force between the device units (VE 1) and (VE2). The counterforce force that the upward movement of the float (5) experiences will be higher as the cross section (OS) becomes larger and the lifting (d) of the device unit (VE2) above the waterline (14) increases (see FIG. 1). For the device unit (VE2) not to emerge excessively from water, it is necessary that VE2 has a relatively large cross section. To overcome this disadvantage (i.e. the design of excessively large cross-sections OS), it is now proposed according to the invention to increase the height of the void volume (7) and concomitantly reduce the cross-section 05 and increase the weight of the device (VE1), for example, by filling a portion of the float ( 5) with water so that a significant interactive force is generated between the device units VE1 and VE2, both during the half period when the device unit (VE1) is in lifting mode and during the half period when the device unit (VE1) is in sinking mode. By these measures it is achieved that -similarly as in the original design -during the upward movement a part of the device unit (VE2) is pulled above the water line ( 14) so as to the upward movement of the float (5), and additionally, during the sinking movement of the device unit (VE1), the device unit (VE2) is forced to be submerged under water until a substantial proportion of the voluminous portion (7) has displaced a significant water volume, thereby creating an upwardly directed counterforce capable to drive the electric generator (EG) also during this phase. In this way, during the second half-phase, the device unit (yE 1) exerts its weight to create a downward force to the device unit (VE2) via the electric generator (EG) coupled to components (VE1) and (VE2).

[0029] The end result is that the electric generator (EG) is driven by the total period of a water wave. A predetermined set point to average power can therefore be achieved with a device smaller cross-section (05) than in the case in which useful energy is gained only during a half wave period.

4.3 Example 1 (I)

[0030] This embodiment can best be understood by referring to figures 13a to 13c. Figure 13a approximately illustrates the operation of a device with an annular float (5) having an outer diameter of 4 m, which protrudes 0.5 m from the water at the equilibrium position. The diameter of the hollow body (3) is 2.8 m, so that the cross-section of the latter is of the same size as the horizontal cross section of the ring-shaped float ( ) (i.e. 6.3 square meters). In this example, a wave amplitude of 4 m and a wave period of 12 s are assumed. The maximum useful power for driving the electric generator (EG) (not shown in the 13a to 13c) at a constant torque is about the potential energy that is stored in the system after the internal device unit VE2 has been pulled 0.5 m from its equilibrium position, i.e. after the maximum lift force acting on the floating body has been attained (then, the floater is just covered by water). It is assumed that useful energy is available only during the half period of upward movement of float (5). The maximum energy available to drive the generator (EG) under constant buoyancy force is equal to the mass of water displaced by the volume of the float (5) multiplied by the density of water (about 1) times g' (9.81 ms -2) times the effective upward displacement delivering useful energy (3m; 4 m -2 (0.5) m = 3 m; see figure 13a on the right). The result is 92.7 Id.

Over a period of 12s an average power of 7.7 kW is delivered. Considering also the energy yielded during the time of variable performance, the average power is even higher and corresponds to the energy value calculated by multiplying the volume of the float (5) times the density of water (about 1) times "g" (9.81 ms -2) times the height of the wave crest (4 m), reduced by the amount of energy required to displace water by the float(s) and by the "pull-up-volume" of the device unit VE2 divided by the time period of 12s. (The maximum average power under the condition of variable buoyancy is then 9.2 kW). (II)

[0031] The above example is repeated with a device wherein the outer diameter of the float (5) is 4 m, but the hollow body (3) has a diameter of only 2 m, so that the cross-section OS of the latter is only 3.14 square meters. In this case, the maximum lifting force that can act upon the float (5) is 46.2 kN and it acts over a constant-force acting distance of only 2 m (4 m -0.5 m -1.5 m = 2 m). This time, the buoyancy force of 46.2 kN is only fully compensated when the internal device unit VE2 was pulled 1.5 m out of water. Again, the maximum average power calculated at constant buoyancy was 7.7 kW, which is not surprising. The maximum average power, under conditions of variable buoyancy force was in this case however 13.5 kW. Also in this case a period of 12s has been assumed. (Ill)

[0032] Now, the above results are compared with the potential energy required to lift a float of diameter of 4 m and height of 0.5 m after it has just been covered by water along a distance corresponding to a wave crest of 4 m (i.e. along a net distance equal to 4 m -0.5 = 3.5 m). If this energy (which is calculated under the condition of a constant lift force) is divided by 12s, one obtains an average power of 17.9 kW. The maximum average power, under the condition of variable buoyancy, in this case is 19.2 kW. This performance corresponds to the maximum deliverable power by a prior art device (http://www.oceanpowertechnologies.com/PDF/PB150 08292012 GFL.pdf). In such types of devices, however, you need a dynamically acting immobile part that should weigh several hundreds of tons. Such devices have a curb weight of more than 100 tons. The ratio of 17.9: 7.7 is about 2.33.

The ratios of 19.2: 9.2 = 2.1 and 19.2: 13.5 = 1.4 are even smaller. The type devices according to the embodiments (I) and (II) above, may not more than 15 tons. The value "15 times 2.33" or even more "15 times 1.4" times is considerably smaller than 100, indicating a clear material saving advantage.

Devices of the type considered in the examples (I) and (II) above were envisaged in the German patent application with the file number 102014003228.0. (IV)

[0033] The inventive apparatus operates as illustrated in figures 13b and 13c in two phases. Therefore, it is necessary that close to the equilibrium position, the internal device unit protrudes above the water line (14) sufficiently, so that during the downward movement of the float (5), the voluminous compartment (6,7) can be pushed substantially below its equilibrium position in the water. This requires that the hollow body (3) has an accordingly elevated weight which however can adequately be overcompensated by an adequately dimensioned float (5). This goal can be achieved in the lengthwise direction by providing a "heavy" portion (5a) which might be water container. During the upward phase (see figure 13b) the device operates as explained in examples (I) and (II). During the downward phase can however, an additional amount of energy be gained (see figure 13c). The maximum calculated average power at a constant driving force of the electric generator (EG) is now 14.4 kW. A direct comparison of Examples (I) and (IV) reveals that under identical conditions, the performance of the inventive device compared with that of the device disclosed in the co-pending application (Reference 102014003228.0 Is) having the same lateral dimensions is twice as high.

4.4 General description of the system according to the invention (I) [0034] The new concept provides -instead of individually coupling a single mobile device unit VE1 of a floating electricity generating apparatus to a single relatively immobile device element VE2 of the same apparatus -for a design in which mobile components K2 of electricity generating units are coupled to corresponding immobile components K1, which are however mounted to a common heavy supporting structure, adapted to float at a predetermined sea depth hung by a sufficient number of adequately sized floats Si, S2. The respective supporting frameworks can be designed as long-shaped (LT) or as a platform shaped (PT) support elements. These "scaffolds" may have a modular structure and be composed of individual, interconnected modules Mi, M2 assembled to larger units (see figures 8, 10, 12).

[0035] In contrast to the immobile elements envisaged in the known prior art devices (OPT) http://www.oceanpowertechnologies.comJPDFJPB1SO 08292012 GFL.pdf, W02011/ 120497) swimming deeply below water waves and counteracting the buoyant force acting upon mobile floats mainly by means of their huge inertial mass of several hundred tons, i.e. by acting as dynamically active counterparts of mobile elements to drive electric generators coupled to them, the proportionately attributed weight of a carrier element (LT, PT) to each individual electric generator may -according to the this new concept -be less than ten tons. This is possible because the elongated (LT) or platform-shaped (PT) support elements with long lift arms (wings (SF) and / or middle wings (MF)) are dimensioned so as to preferably exhibit at least the length of a sea wave length in the intended field of application. The underwater lift arms of the support elements suspended on floats Si, S2 undergo a rocking motion, which is caused by the water waves, with the center of gravity of the entire system, however, remaining almost immobile (see figure 14a). If the maximum total force summed-up in a single direction (upward or downward) by all the devices (VR1, VR2, VR3) mounted a support member (LT, PT), is neither greater than the effective weight of that support member nor of the remaining buoyant capacity of floats Si, S2 on which the support member (LT, PT) is suspended, the immobile components Ki of the individual device units -apart from small fluctuations -remain almost at the same location while the corresponding mobile components K2 undergo periodic motions together with the sea waves and drive the assembly of electric generators (EG). It is only important that modern construction materials are used so as to enable a sufficiently stable construction a support member module having a length of 25 m comprising two wings each of 25 m length and a total weight of about 40 tons. When on such a module ballasts of additional weight (GW) of another 20 tons are fixed (e.g. concrete blocks, sand sacks or scrap; materials having a much higher density than the density of water), then it is possible to mount on a support member (LT, PT) four electrical energy generating devices (VR1, VR2, VR3), which can be driven individually under conditions creating individual peak forces of the order of 100 kN. Depending on the intensity of sea waves, each individual of such devices, can generate an average power of 10 to 60 kW. (II)

[0036] Alternatively, a longitudinal composite of several interconnected support members (LT, PT) with a total length of two to three or more water wavelengths can be formed and positioned obliquely to a wave front (see Figure 11 right) up and figure 14b). If bi-directionally operating device units of type VR3 for example are mounted on the individual modules of the support elements (LI, PT), then an attractive force acts on the support member when the device VR3 faces a crest of a wave front (as explained below) and a compression force, when the device VR3 lags a wave crest. In addition, along a water wavelength, for nearly half of the submerged elongated support member (and specifically in the region of a wave trough), the gravitational force due to its weight predominates, whereas the other half (in the region of a wave crest) experiences a strong buoyancy in the opposite direction.

The overall effect is that every single point of the support member suspended in water undergoes a small vertical oscillations, whereas the mobile components K2 of the devices VR3 oscillate with an amplitude of the magnitude of a wave crest. It is noteworthy that in such long chains of interconnected modules Ml, M2, which are directed obliquely to a wave-front, it is not even necessary to equip all modules with extra-long lift arms (wings (SF) and! or middle wings (ME)), since in the longitudinal direction of the system, a repeating pattern of vertical opposing forces results.

4.5 working modes of the power generating devices (VR) [0037] An electrical energy generating device (VR), which is intended to be attached to an immobile base, can in principle operate in three different modes: (I) Type VR2 -attraction mode [0038] Some years ago it was proposed to attach an electric generator on the seabed and operate it with the buoyant force exerted on a float lifted by a wave crest, the bottom of the float being connected to the generator via a cable ( W02004 / 085843). This principle is illustrated by the drawing on the right side of figureS. For illustrative reasons the figure depicts a winding device (17), a cable (SL1) separated by a rewind device (RS) of known type. As the float (WS) is in upward movement, the generator (EG) is driven. During the phase of a wave trough, the cable (SL1) is rewound. Generators, which are referred to herein as generators of type VR2 operate only during the "attraction phase".

[0039] Alternatively, the electric generator (EG) can be located in device space (9), which is arranged in a region of a tubular component (Ki) (see figures 3a, 3b and Son the left). As explained in the International Patent Application ( W02011 / 120497), a sufficiently high rotational speed of the generator rotor is achieved which matches the linear velocity of a vertically oscillating float component (K2), which is coupled to the generator (EG), so that the desired performance can be attained. In the figures 3a, 3b, a piston (11) is shown to be part of a gear mechanism (10, 11), which, according to a specific embodiment, has a teeth mechanism engaging in a gear of a transmission apparatus (10) only during the upward movement of the piston (11), so that the rotor of the electric generator (EG) -or dynamo -is set in rotary motion. The transmission device is designed such that during the downward movement of the piston (11), its mechanism is in free-running mode, similar to the backward movement of the pedal of a conventional bicycle. The upward movement of the piston (11) connected via bracket (21) with the mobile sliding element (LK2) of the mobile component (K2) of the device (VR, VR2) is effectuated by the buoyancy force acting on the float (5, WS) attached to the mobile component (K2).

(II) Type VR1 compression mode [0040] The device described above can in an alternative mode operate exclusively in a compression mode.

In that case, it is necessary that the piston (11) is in freewheel mode during its upward movement, whereas its teeth engage in the teeth of the gear of the transmission device (10) only during its descent. The force required to drive a generator during the downward movement of the piston (11) can be achieved in that instead of an empty float (5, WS), a combination of float(s) and of a massive body (such as a water-filled vessel ( Sa)) are attached on the mobile element (LK2) of the mobile component (K2), (see figure 2). During the formation of a wave crest, the lifted massive body (viz, the water-filled vessel (5a)) gains potential energy that is released during the phase of a wave trough.

[0041] Alternatively, a according to the above explanatory principles, a solid body or a vessel filled with water (Sa) enriched with potential energy can release the corresponding energy through the pressure exercised upon the piston of a pneumatic device as illustrated in figure 4 (the means of interaction between the vessel (Sa) and device (VR2) are not shown in figure 4). The pressure relief valves (24, 27) open up as shown by the arrows in figure 4. when the vessel (5a) exercises pressure on the piston (22), the operating fluid flows from left to right the depicted container. The rotor (25) of this device is coupled with the rotor of an electric generator (25) which is set in rotary motion. The liquid flows through the tube (26) into the right space and from there hydrostatically through valve (27) to the left of the container during the phase when no pressure is applied to the piston (22).

(Ill) Type VR3 -bidirectional mode [0042] The device described in the first paragraph under point (II) above can work in both attraction and compression modes when the float (5) is sufficiently larger than the vessel (Sa) filled with water as explained in connection with the description of device 2 as long as the teeth of the piston (11) engage in the teeth of the gear of the transmission device (10) both during the upward and downward motion of the piston (see figures 3a left and S left).

[0043] Alternatively, the coupling of the mobile element (LK2) to the transmission device (10) can be accomplished via cables (SL2) attached to the tooth-free piston ( 11) and connected to the bobbin / rewinders ( 17, RS). Since in such a case, only the narrow area above the piston ( 11) is subjected to tensile forces (since otherwise the piston operates under heavy duty only in compression mode when the traction cable (5L2) is pulled downwards), only certain portions of the piston need be made of a material having very high tensile strength. It is therefore sufficient if the pulling cables have the required tensile strength and this is easier to achieve because a modern pull rope may have a tensile strength of 2000 N /mm2.

4.6 Long-shaped (elongated) and platform-shaped support members (LT, PT) -Basic Structure [0044] Heavy duty beams and lift arms made of special steel having a length of 25 m, can typically carry heavy loads at points distributed along the beam or lift arm, which can weigh a total of up to a factor of 20 times more than the beam's own weight. Therefore, a carrier element (LT) of 25 m length, which is suspended from its two ends in the water and at the same time forces of 100 kN (i.e. of about 10 tons) are exercised in the same direction at four distinct sites spread along the trunk of the carrier element (LT), is expected to weigh at least two tons (i.e. have a mass of 2000 kg). A construction weighing five tons should therefore be sufficiently strong for all practical applications.

For the same reason, it is sufficient that the total weight of two side wings (SF) fixed perpendicularly to the main body of the carrier element at its two ends, need not be higher than six tons. A frame structure, which should carry a load of 40 tons and have a form as that shown in figure 6 or in the left of figureS need not have a weight of exceeding 12 tons. The components (Ki) and (K2) of an apparatus (VR), including all devices and support materials (see figures 3a, 3b, 5, 6) can weigh less than 10 tons per device of a height of 10 m. For a device of the type described in connection with figures on the left, it may be of advantage that towers (mM) are mounted on the trunk of the carrier (support) element (LT) or on the modules (Ml, M2), especially when the support elements (LI, PT) are intended to be submerged in very deep waters. If a steel construction has a weight of 50 tons) in the water will have an effective weight of 44 to 45 tons, since the density of iron is about 7.8.

Under such circumstances) it may be of advantage that extra weights (GW) of an inexpensive material, such as cement blocks, are attached to the support element (LT) as ballast (see FIG. 8).

[0045] The entire construction of a support element (LT), which carries four power generating devices may weigh less than 60 tons, thus representing a proportionate weight of 15 tons per device. In addition, the floats suspending the support element (LT) may have a total desired void volume of about 80 m3 (in order to exhibit the requisite "reserve" lifting capacity). Even taking into account the weight of the float (51, 52) and the associated fastening material which may have a cylindrical shape as shown in figure 9, the proportionate weight per power generating device will not be higher than 20 tons. This proportionate weight per device is much less than the curb weight of 140 tons exhibited by individual floating electricity generating devices of the type requiring very massive immobile parts counterbalancing the movement of floating components dynamically through inertial forces (cf. OPT PB1SO). Modern polyethylene floats are available for the production of jetties and catamarans (which can serve as float 51, 52 in the present invention) having a net weight of substantially less than one-tenth of their lifting capacity.

[0046] If it considered expedient to increase the inertia of a support element (LT), especially near its end regions, or of assemblies consisting of several modules (see figure 14b upper part), reservoirs (WR) which can be filled with water may be mounted to the trunks of individual modules (Ml, M2). The reservoirs may have openings (19) through which water penetrates their interior. If the number and size of the openings are not very large) it takes some time until the respective reservoirs (WR) are full, but then it is not necessary to stopper the openings since the reservoirs maintain their inertial damping action despite the existence of openings (see figure 6). If it is desired that the frame of the support member is suspended in a higher position within water and that the reservoirs (WR) are located in deeper locations where the pressure fluctuations occasioned by surface waves are more negligible (this is already happening at a depth exceeding half the wavelength of sea waves), it is possible to envisage construction as shown in figure 7.

4.7 Modular design [0047] It may be desirable that the dimensions of the elongated or platform-shaped overall systems (LT, PT) exceed three times the length of the water wavelengths, so that local forces caused by the individual waves, have little influence upon the position of the floating scaffold. For weight / stability reasons, it may be advantageous that the individual rigid elements of the system are not much longer than 25 m to 30 m each. The overall system can therefore be made up of individual modules (Ml, M2) constructed in different shapes, as shown in figures 8, 10 right and 12. The connections between the adjacent modules should be flexible. The required freedom of rotation may be achieved by the use of spherical or bi-axial connectors) such as the coupling elements Cl, C2 or C3 illustrated in figure 8.

Flexible connections can also be achieved in inexpensive and stable manner, if adjacent modules are connected together via traction cables (ZS) with shock-absorbing intermediate buffer elements (PF) disposed at the ends of the modules. (see figure 8).

[0048] Figure 12(a) shows an elongated structure comprising two modules, each equipped with two side wings and connected to a module, which only has a longer middle wing. The advantage of a longer middle wing is that it can be exposed to several wave troughs and wave crests at the same time when the water wavelength is substantially smaller than the length of the central wing (MF). In this case) a plurality of vertically oriented forces acting in opposite directions upon the skeleton of the central wing (MF) have the net effect that the former is not substantially accelerated in a particular direction. The disadvantages of a very long structure are associated with construction difficulties.

Figure 9 shows the possibility of strengthening long wing structures via traction cables (as in suspension bridges). Lift cords (SL) are attached to mini towers (MTR) and to the terminal ends of a wing framework. The advantage of using tension cables is their higher tensile strength compared to that of rigid elements.

[0049] Figures 10 (right) and 12(b) illustrate the modular structure of platform-shaped structures, which result from the connection of individual modules which are connected to one another both over the ends of their side wings, and the ends of their base bodies.

4.8 Embodiment 2 (I) Use of a platform-like system [0050] In the known floating electrical energy generating devices, their relatively immobile components must be able to swim themselves (otherwise the entire device would be sunk) and therefore they must have an average density close to the density of water. Thus, those elements must have a very high inertial mass and for not being materially affected by the wave motion, most of their volume must lie at a depth in which the influence of water waves is small (cf. W02011 / 120497). Such inertial masses should be located at a depth greater than 8 to 10 m, even greater than 15 m.

[0051] Such a limitation does not apply to the massive stands of elongated and platform-shaped support members (LT, PT). Since such structures are made of materials whose density is much higher than the density of water, the force due to their own weight is far more important than the buoyancy of the rising and falling water wave masses. The buoyancy force experienced such scaffolding structures according to the invention is mainly that "transmitted" by the buoys (floats) 51, 52, from which the said structures are connected. The buoyancy force is stronger at the a location where there is currently a wave crest; the scaffold's location corresponding to the position where float (51, S2) is connected experiences over time a variable buoyant force which on time average remains more or less constant.

[0052] In a region where water waves propagate at a height between 2m and 4m, a scaffold like that shown in figure 12(b) may be suspended from floating bodies (Si, 52) at a depth of 6 to 8 rr and be oriented with its long axis against the propagating wave-front. The individual modules tend to experience a rocking motion, as explained under point 4.4 (I) in conjunction with figure 14(a). However, the axis along which the individual devices (VR1, VR2) are disposed remains substantially in the same position of equilibrium. As a consequence of an end-to-end coupling of the individual modules, part of the lift force experienced by a specific module at a particular moment of time is transferred to an adjacent module so that the tendency of positional variation at each point is attenuated. In this example devices of types VR1 and VR2 are employed according to a certain pattern. Since the devices of type VR1 (closed circles) work only in attraction mode when a mountain (swelling) of water is formed) they are preferably arranged away from one another so that each of these devices can absorb the maximum available wave energy. Therefore, devices of type VR2 operating in compression mode are arranged between the former devices. The individual devices (VR1, VR2) are mounted to the scaffolding by the intermediate of pivot axes like the axes of rotation (AX) or directly through swiveling elements (16), which can be in the form of spherical connections.

[0053] In the system of this example 24 unidirectional operating devices are provided. Each of these devices is provided with a float having a load capacity of 6 tons (about 60 kN). In an area with 3 m high sea waves having a period of 12s the resulting average power would be up to 360 kW.

[0054] Figure 9 illustrates the effective forces on the individual modules resulting from the operation of the individual devices. The open arrows indicate the compression forces that are caused by devices of the types VR1 and VR3 and the full arrows indicate the forces of attraction caused by devices of the types VR2 and VR3.

(II) Use of a long-shaped system [0055] A long-shaped system comprising four modules may take the form of arrays as in shown in figures 12(a) and 8 or the form of a series of frames with short wings as depicted in figure 7. Inertial elements in the form of water reservoirs (WR) are not necessary, but can be advantageously used as oscillation dampers if they are mounted at the end modules of the overall assembly.

[0056] The system, which is diagrammatically shown in figure 14a (bottom plan view, side view above) contains 4 modules, each module supporting four devices of the type VR3. The entire system is suspended from floats 51, 52 into the water at a depth of 6 m to 8 m, whereby the floats can compensate the weight of the load and the compression forces of the individual device VR3. The system is extending with its length obliquely oriented to a wave-front (e.g. through use of anchors) so that the individual devices are fully exposed to a propagating wave-front. The individual devices are directly mounted on the trunks of the modules through swiveling anchoring elements (16). Each device is equipped with a float having a lifting capacity of 6 tons (about 60 kN) and being bi-directionally active, as explained in section 4.5 (III). The system comprises 24 devices. In an area with 3 m high sea waves and a wave period of 12 s, that system exhibits an average power of up to 640 kW.

4.9 Concluding remarks [0057] The provision of modular complete systems are advantageous not only from the point of saving material costs. Since multiple device units are mounted on solid scaffolds, wiring between devices is simpler. Since the skeleton members are constructed separately from the power generating elements, the logistics of service and transport is also easier. Figure 15 diagrammatically illustrates a further potential. If the solid components (K1) of adjacent devices operating asynchronously (e.g. devices of types VR1 and VR2) are arranged in the direction of a common axis of rotation (AX) and if the mechanical elements of the individual devices are connected by means of appropriate coupling mechanisms (as explained in connection with figure 3a) to that axis (Ax), then, a single, common electric generator (EC) can be driven by axis (Ax). For this purpose, it is sufficient for example, that a torque is transmitted individually from each device to the axis of the generator motor. This may occur via the bobbin / rewinders (17, RS), wherein the rope (SL2) of the one device drives the rotor in its downward movement and the rope (SL2) of another device does the same in its upward movement. Even though not shown in the figures, it is possible that the construction of the individual devices (VR) is appropriately modified so that the equipment room (9) of the component (Ki) is disposed in a lower location, so that the piston (11) can move in an envelope (not shown) disposed below the lateral position of the skeleton of a module (Ml, M2). This modification is advantageous for applications in locations where very high waves prevail.