AU2011223993A1 - Wave driven electrical power generation - Google Patents

Abstract

An electrical energy generation system including a float means (10) having a first part (40) adapted to contain and retain water and at least one second part (45) acting as floatation elements, the float means (10) being positionable, in use, within a water area (20) subject to wave action whereby the float means rises or lowers in response to said wave action; pump means (12) driven by movement of said float means (10) under influence of said wave action to pump water from said water area (20) to an elevated water containment zone (15) for said water; a turbine means (23) disposed substantially below said elevated water containment zone (15), an electrical generation means (25) driven by said turbine means (23); and water flow delivery means (22) for passing water from said elevated water containment zone (15) to said turbine means (23) to thereby drive said turbine means (23) and said electrical generation means (25). In K 6.O eU

Description

Pool Section 29 Regulation 3.2(2)) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Wave driven electrical power generation system The following statement is a full description of this invention, including the best method of performing it known to me: P111AAAU/0610 I WAVE DRIVEN ELECTRICAL POWER GENERATION The present invention relates to improvements in systems for generating electric power from sea or ocean movement, in particular, wave generated motion. 5 One known arrangement for generating electrical energy from wave power is to provide a structure for waves to run through specially designed races to drive a turbine in the forward direction of flow but such arrangements have a difficulty in that the force applied by waves provides only an intermittent driving force for the turbine or turbines. 10 US 3970415 discloses an arrangement wherein fixed pumping stations are provided undersea, each station having a float which rises and falls with wave motion, thereby regularly pumping water to a hydraulic turbine to generate electricity. Although this provides a somewhat more regular driving force to the turbine, fluid flow to the turbine is intermittent. Furthermore, the number of pump 15 cycles per second and volume of fluid delivered to the turbine will depend on the size and frequency of the waves, further contributing to irregular and intermittent power availability. Furthermore, the pumping mechanism is inherently inefficient. EP1013953 discloses an arrangement wherein an undersea pumping mechanism uses wave power to pump water to an elevated tank, thereby 20 providing a constant source of elevated water for use in a hydraulic turbine. However, this arrangement relies upon a float attached via a cable to the pumping piston. Vertical movement of the float translates directly to vertical movement of the piston and no leverage advantages are gained. Furthermore, the pumping mechanism is again inherently inefficient. When waves are small 25 and have a high frequency, the arrangement will result in very short piston strokes and frequent changes of piston direction. This is inefficient and ultimately results in less fluid being delivered to the elevated tank, and hence less power generation capacity. The objective of the present invention is to provide an improved system for 30 creating electrical energy from wave power. Accordingly, one aspect of the present invention provides an electrical energy generation system including a float structure positionable, in use, within a water area subject to wave action whereby the float structure rises or lowers in 2 response to said wave action; said float structure being supported by a lever member, said lever member being supported at a fixed fulcrum point for pivoting motion about said fixed fulcrum point by wave action forces applied to said float structure; pump means operably connected to said lever arm and driven in 5 response to said pivoting motion of the lever arm to pump water from said water area to an elevated water containment zone; a water turbine positioned substantially below said elevated water containment zone; an electrical generation means driven by said water turbine means; and water flow delivery means for delivering water from said elevated water containment zone to said 10 water turbine means to thereby drive said water turbine means; said electrical generation system being characterized by said float structure including a first part having a hollow internal water retaining zone adapted to receive and hold a volume of water in use, said float structure further including a second part having at least one floatation element to ensure said floatation structure floats at or near 15 water surface of the water area in which it is positioned in use. Preferred features of the present invention may be as defined in claims 2 to 13 inclusive as annexed hereto, the subject matter of these claims being hereby incorporated in the disclosure of this specification by this reference thereto. 20 One preferred embodiment of this invention may be as shown schematically in the annexed drawings in which Figure 1 shows schematically a preferred embodiment of the present invention and Figure 2 shows a preferred pumping mechanism arrangement, and Fig 3 shows schematically a section view along line III-III of Fig 1. Further preferred features of this invention will be 25 apparent from the following description of the preferred embodiment illustrated in the annexed drawings. Referring to Figure 1 a float structure 10 is shown supported on a water area 20 subject to wave action. The water area 20 might be sea water or ocean water but does not necessarily need to be so. For example, a freshwater lake, 30 dam or reservoir that is commonly subject to wave action on its surface might also be used. The float structure 10 is supported at one end of a lever member 11 with a pump means 12 pivotally and drivingly supported by the lever member 11 intermediate a fixed fulcrum 24 and the float structure 10. Thus when wave 3 action applies forces on the float structure 10, the float structure 10 rises and lowers with a consequent effect on the pump means 12. In an alternative embodiment, the position of the fixed fulcrum is adjustable to suit differing tidal heights. The positioning of the pump means 12 as shown in Fig 1 allows a 5 pumping action only on a downward movement of the lever member 11. A water delivery conduit pipe or the like 13 is provided with an intake end 14 in the water area 20 with the pump means 12 being positioned and configured to draw water through the intake 14 and deliver same to an elevated water containment zone 15. The intake end 14 may have screens to prevent seaweed 10 or other undesirably matter from entering the pumping means and conduit. The containment zone 15 might be a pond, dam or tank situated at an elevated position, for example on top of a cliff face 50 adjacent the body of water 20 or alternatively, it might be a separately built elevated water containment tank. The pump means 12 is schematically illustrated as a reciprocating piston pump but 15 other pumping structures might also be used. The delivery pipe 13 has a pair of check valves 16, 17 on either side of the pump means 12 permitting water flow only in a direction towards the elevated water containment zone 15. The check valve 17 is conveniently also openable or closable in response to water levels in the containment zone 15. Conveniently the check valve 17 is maintained open 20 for the pump means 12 to deliver water to the containment zone 15 along the delivery pipe 13 until the water level reaches a predetermined level in the containment zone. Operation of the check valve 17 might be controlled by a float sensor 18, lever arm 19 and a connector 21 that might be mechanical or electrical. Alternatively water levels in the containment zone 15 might be sensed 25 by any means with electrical signals being delivered to the check valve 17 to control same. Conveniently the aforesaid arrangement is provided so as to maintain sufficient level of water in the containment zone 15 to ensure a continuous outflow of water along a delivery path 22 to a turbine 23 arranged to drive 30 electrical energy generation means 25, the turbine 23 being located below the level of the water containment zone 15. The turbine 23 and electrical energy generation means 25 are illustrated in figure 1 within the water area 20 but it will be recognised that this is not essential.

4 Referring now to the embodiment shown in Figure 2, the pump means 12 has a piston 30 pivotally connected to the lever arm 11 and a cylinder 31 within which the piston 30 moves. The cylinder 31 is in fluid communication with a pump cavity 35 having a fluid inlet port 36 and a fluid outlet port 38, each port having a 5 one-way poppet valve 37, 39. When the float 10 moves downwardly due to wave action, the piston 30 also moves downwardly. Poppet valve 39 is closed in outlet port 38, while the pressure drop in cylinder 31 and pump cavity 35 causes poppet valve 37 in inlet port 36 to open. Fluid is drawn through the intake end 14 and port 36, priming the 10 pump means 12. When the float 10 moves upwardly, the piston 30 moves downwardly in cylinder 31. Fluid is pumped from the cylinder 31 into pump cavity 35. The inlet port 36 is closed by poppet valve 37 and the outlet port 38 and poppet valve 39 are opened, hence fluid is pumped through the outlet port 38 to the elevated 15 water containment zone 15. Advantageously, use of poppet valves 37, 39 to open and close the inlet and outlet ports 36, 38 efficiently maintains flow of fluid to the elevated water containment zone, as only a small amount of valve lift is required for high flow rates through the port. Hence, when waves are small and have a high frequency, 20 frequent changes of direction in the piston movement do not cause the level of efficiency loss associated with a flap valve, which takes more time to open and close and hence does not provide the most efficient flow of fluid. Additionally, as the float means (10) is fixed to the lever arm, wave energy is not wasted at times when, for example, a cabled arrangement has slack in the 25 cable and accordingly is not exerting any driving force on the pumping means. The float and lever arm arrangement enhances the efficiency of the pumping mechanism and accordingly increases the availability and capacity of power generation. In a preferred embodiment, the fluid communication from the cylinder 31 to 30 the pump cavity 35 enters the pump cavity 35 at a point 40 which is above the maximum height of the inlet poppet valve 37. When the piston 30 begins to move downwardly, fluid travelling from the cylinder 31 to the pump cavity 35 will exert a downward force on the poppet valve 37, causing it to close more quickly and 5 hence more efficiently. Preferably, the fluid communication from the cylinder 31 to the pump cavity 35 also enters the pump cavity 35 at a point 40 which is below the minimum height (closed position) of the outlet poppet valve 39. When the piston 30 begins to move upwardly, fluid travelling from the pump cavity 35 to the 5 cylinder 31 will exert a downward force on the poppet valve 39, causing it to close more quickly and hence more efficiently. In a further preferred embodiment, the poppet valves are arranged to operate along a vertical axis, in order that they will be assisted to close more quickly due to gravity. This further enhances the ability to operate at high speeds. 10 The poppet valves 37, 39 are conveniently also openable or closable in response to water levels in the water containment zone. In one preferred embodiment, if a high level is sensed in the water containment zone, the inlet port poppet valve 37 is held open. This will prevent an overflow of the water containment zone, and will also prevent a build-up of excess pressure in the 15 cylinder and pump cavity should outlet port poppet valve 39 be closed and pumping mechanism 12 continue to operate due to wave action. In one preferred embodiment, a float sensor in the elevated water containment zone operates a wire attached to inlet port poppet valve 37, causing the inlet port poppet valve to open. However, many other sensor and actuating means may be utilised. 20 Figs 1 and 3 illustrate the novel float structure 10 proposed in accordance with this preferred embodiment. The drawings show a central first part 40 formed as a container 41 defining an internal volume 42 to receive and retain water 43 therein. The water is conveniently water from the surrounding water 20. The walls 44 of the first part 40 may be rigid, semi-rigid or flexible and the material of 25 same should be such as to prevent or substantially minimize corrosion arising from contact with the water 20. The purpose of the first part 40 containing the water 43 is to provide a float part that has reasonably substantial weight and will provide a greater force to the lever 11 and piston 30 during a pumping motion, i.e. as the piston 30 moves downwardly to pump water along the line 13 to the 30 elevated containment zone 15. The float structure 10 also includes at least one and conveniently two second parts 45 in the form of floatation elements 46, each defining a volume 47 that might be filled with air or alternatively, a floatation material such as foam plastic material. In the latter case, defined containment 6 walls may not be required. The floatation element or elements 46 are provided to ensure the floatation structure 10 remains floating at or near the surface of the body of water 20 such that it rises and falls in response to wave action thereon. The or each of the floatation elements 46 may be connected to the first part 40 by 5 securing straps 48 or any other suitable connection means. It will of course be appreciated that many modifications to the illustrated system might be included including providing multiple float members 10 to drive multiple pump means 12 to deliver fluid to the same or to different elevated water containment zones. Fluid from the containment zone or zones might be delivered 10 to multiple turbines 23 or to a single turbine 23.

Claims (14)

1. An electrical energy generation system including a float structure positionable, in use, within a water area subject to wave action whereby the float structure rises or lowers in response to said wave action; said float structure 5 being supported by a lever member, said lever member being supported at a fixed fulcrum point for pivoting motion about said fixed fulcrum point by wave action forces applied to said float structure; pump means operably connected to said lever arm and driven in response to said pivoting motion of the lever arm to pump water from said water area to an elevated water containment zone; a water 10 turbine positioned substantially below said elevated water containment zone; an electrical generation means driven by said water turbine means; and water flow delivery means for delivering water from said elevated water containment zone to said water turbine means to thereby drive said water turbine means; said electrical generation system being characterized by said float structure including 15 a first part having a hollow internal water retaining zone adapted to receive and hold a volume of water in use, said float structure further including a second part having at least one floatation element to ensure said floatation structure floats at or near water surface of the water area in which it is positioned in use.

2. An electrical energy generation system according to claim 1 wherein said 20 first part has flexible walls surrounding said hollow internal water retaining zone.

3. An electrical energy generation system according to claim 1 wherein said first part has rigid or semi-rigid walls surrounding said hollow internal water retaining zone.

4. An electrical energy generation system according to any one of claims 1 to 25 3 wherein the or each said floatation element comprises one or more air containing zones.

5. An electrical energy generation system according to any one of claims 1 to 3 wherein the or each said floatation element comprises one or more floatation members made from foam plastic material. 8

6. An electrical energy generation system according to any one of claims 1 to 5 wherein said pump means pumps water to said elevated water containment zone only on a downward stroke provided by said float structure.

7. An electrical energy generation system according to any one of claims 1 to 5 6 wherein a check valve is provided in an outlet flow from said pump means permitting water flow only in a direction towards said elevated water containment zone, said check valve being opened to allow water flow towards said containment zone when water levels in said water containment zone drop to a first predetermined level. 10

8. An electrical energy generation system according to claim 7 wherein operation of said check valve is controlled by a float sensor in said elevated water containment zone.

9. An electrical energy generation system according to any one of claims 1 to 8 wherein water level in said elevated water containment zone is maintained at at 15 least a second predetermined level whereby water continuously flows via said water delivery means to said turbine means.

10. An electrical energy generation system according to any one of claims 1 to 4 wherein said float structure is supported at one end of said lever member with the pump means being connected to said lever member intermediate said one 20 end and said fixed fulcrum point.

11. An electrical energy generation system according to any one of claims 1 to 10 wherein said pump means has a piston pivotally connected to said lever arm, a cylinder within which said piston moves, said cylinder being in fluid communication with a pump cavity having a water inlet port and a water outlet 25 port, each said port having a one-way poppet valve.

12. An electrical energy generation system according to claim 11 wherein said inlet port poppet valve and said outlet port poppet valve move upwardly along a vertical axis to open and downwardly to close. 9

13. An electrical energy generation system according to claim 11 wherein the fluid communication from said cylinder to said pump cavity enters said pump cavity at a point above the height to which said inlet port poppet valve may open.

14. An electrical generation system according to claim 1 and substantially as 5 described herein with reference to the accompanying drawings. JOHANN GRANITZER WATERMARK PATENT & TRADE MARKS ATTORNEYS P35009AUOO