WO2011123871A1 - Dam structure and hydroelectric dam construction therefrom - Google Patents

Dam structure and hydroelectric dam construction therefrom Download PDF

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Publication number
WO2011123871A1
WO2011123871A1 PCT/ZA2011/000017 ZA2011000017W WO2011123871A1 WO 2011123871 A1 WO2011123871 A1 WO 2011123871A1 ZA 2011000017 W ZA2011000017 W ZA 2011000017W WO 2011123871 A1 WO2011123871 A1 WO 2011123871A1
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WO
WIPO (PCT)
Prior art keywords
dam
dam structure
water
reservoir
hydroelectric
Prior art date
Application number
PCT/ZA2011/000017
Other languages
French (fr)
Inventor
Peter Phillip Jordaan
Original Assignee
Peter Phillip Jordaan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Peter Phillip Jordaan filed Critical Peter Phillip Jordaan
Priority to AP2012006540A priority Critical patent/AP2012006540A0/en
Priority to MA35334A priority patent/MA34180B1/en
Publication of WO2011123871A1 publication Critical patent/WO2011123871A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B9/00—Water-power plants; Layout, construction or equipment, methods of, or apparatus for, making same
    • E02B9/08—Tide or wave power plants
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B9/00—Water-power plants; Layout, construction or equipment, methods of, or apparatus for, making same
    • E02B9/02—Water-ways
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/08—Machine or engine aggregates in dams or the like; Conduits therefor, e.g. diffusors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/141—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy with a static energy collector
    • F03B13/144—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy with a static energy collector which lifts water above sea level
    • F03B13/145—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy with a static energy collector which lifts water above sea level for immediate use in an energy converter
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/20—Hydro energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

  • THIS invention relates to a dam structure and hydroelectric dam construction therefrom. More specifically, the invention relates to an alternative energy source in the form of an oceanic hydroelectric dam for converting the energy stored in sea waves to electrical power.
  • Water wheels are, or were in the past, commonly used in water ways having flow in a single direction, for example a river.
  • the intermittent nature of ocean waves makes the continuous turning of the water wheel very difficult and impractical.
  • Ramp type technologies as also known.
  • the first of this type of technology is disclosed in United States patent 4,263,516 in the name of Papadakis, G.M., which utilises a ramp having a series of water channels in fluid communication with a water wheel. As a wave rides upwardly on the ramp, water falls under the force of gravity down the channels and onto the water wheel, thereby driving a generator coupled to the water wheel.
  • a hydroelectric dam including: a dam structure anchored to the floor of a body of water and comprising a first ramp side and a second reservoir side, the first ramp side positioned to face the oncoming wave side of the body of water and adapted to direct the oncoming waves upwardly and over the dam structure; a reservoir into which the waves spilling over the dam structure are captured and contained, the reservoir being shaped and sized to contain a first volume of water below a mean still water line of the body of water and a second volume of water above the mean still water line of the body of water, the first and second volumes of water jointly defining a common volume of reservoir water; and means for generating power, the power generating means being driven by drainage of the reservoir water from the reservoir back to oncoming wave side of the body of water, wherein the second volume of water contained in the reservoir provides the pressure head required to drive the power generating means.
  • the reservoir is typically drained through drainage ducting comprising an inlet positioned in the reservoir and an outlet positioned in the oncoming wave side of the body of water.
  • the drainage ducting is adapted to communicate the draining water to the power generating means between its passage from the inlet to the outlet.
  • the inlet may be spaced a distance away from the second reservoir side to minimise any turbulence effect on the inlet from the waves spilling over the dam structure, thereby ensuring efficient operating of the power generating means.
  • the outlet is also spaced a distance away from the dam structure towards the oncoming wave side of the body of water to minimise any interference effect from the oncoming waves.
  • the outlet may be directed in the same direction as a prevailing current in the body of water to aid drainage through a suction effect. Directing the outlet in the direction of the prevailing current also has the affect of further reducing any interference effect from the oncoming waves.
  • the drainage of the reservoir is controlled or designed such that the volume of water spilling over the dam structure and into the reservoir is equal to or greater than the volume of water being drained from the reservoir, thereby maintaining the second volume of water and providing a pressure head for continuously driving the power generating means, the power generating means being one or more water driven turbines.
  • the reservoir is defined by at least the second reservoir side of the dam structure and the floor of the body of water to which the dam structure is anchored.
  • the reservoir may be defined by the second reservoir side of the dam structure, the floor of the body of water to which the dam structure is anchored and that portion of landmass extending inland from an original shoreline on which the oncoming waves contacted land prior to the construction of the dam structure and a new shoreline on which the reservoir water contacts the land post construction of the dam structure. It will be appreciated that the new shoreline is at a higher sea level than the original shoreline.
  • the reservoir may be defined by the second reservoir side of the dam structure, the floor of the body of water to which the dam structure is anchored, side walls extending between the dam structure and the shore and that portion of landmass extending inland from an original shoreline on which the oncoming waves contacted land prior to the construction of the dam structure and a new shoreline on which the reservoir water contacts the land post construction of the dam structure.
  • the reservoir may be defined by the second reservoir side of the dam structure and the floor of the body of water to which the dam structure is anchored, the dam structure being constructed to form a closed loop.
  • the reservoir may be defined by the second reservoir side of the dam structure, a secondary dam wall structure and the floor of the body of water to which the dam structure is anchored, the dam structure and secondary dam wall structure being constructed to jointly form a closed loop with the first ramp side of the dam structure facing the direction of the prevailing waves.
  • the first ramp side of the dam structure may comprise an operatively lower end, an operatively upper end and an upwardly directed sloped or curved ramp surface extending from the operatively lower end to the operatively upper end of the first ramp side.
  • the first ramp side of the dam structure comprises an operatively lower end, an operatively upper end and an parabolic ramp surface extending upwardly from the operatively lower and end to the operatively upper end of the first ramp side.
  • the parabolic surface is defined by a parabola having an axis of symmetry substantially parallel with the mean still water line of the body of water and a focus point located above the operatively upper end of the first ramp side so as to reflect oncoming waves coming into contact with the parabolic ramp surface toward the focus point such that the waves ride upwardly and over the dam structure.
  • the focus point of the parabola is located further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side, promoting the wave to ride upwardly and over the dam structure while reducing the possibility of a wave from breaking on the dam structure, thereby minimising damage thereto.
  • the parabola comprises a vertex, the vertex being located above and further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side.
  • the first ramp side of the dam structure is substantially perpendicular to the prevailing wave flow direction.
  • the dam structure may be constructible in- situ or modularly. It will be appreciated that a modularly constructed dam structure is generally constructible by modular dam structure units, the modular dam structure units may be buoyant for the purpose of transportation and capable of being sunk into position during construction.
  • the hydroelectric dam may further comprise one or more guiding formations spaced apart from one another along the dam structure for at least partially guiding the oncoming waves correctly onto the first ramp side of the dam structure.
  • the guiding formations have at least one vertical wall extending between the operatively lower and upper ends of the first ramp side of the dam structure. More preferably, the at least one vertical wall of the guiding formation is sloped or curved in the horizontal plane such that the angle between the operatively upper end of the first ramp side and a line passing between points of contact of the vertical wall with the operatively upper and lower ends of the first ramp side is substantially obtuse.
  • the at least one vertical wall of the guiding formation has a parabolic curvature with a secondary axis of symmetry substantially in the direction of the prevailing wave direction and with a secondary focus point located further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side.
  • the guiding formation is wedge shaped having a thin edge positioned nearer the operatively lower end of the first ramp side, a thicker end positioned nearer the operatively upper end of the first ramp side and vertical walls, sloped or curved, extending between the thin edge and the thicker end.
  • the guiding formations are modular guiding formation units, the modular guiding formation units may be buoyant for the purpose of transportation and capable of being sunk into position during construction.
  • the drainage and/or the power generating means may be housed at least partially in the dam structure and/or the guiding formations.
  • the drainage and/or the power generating means may be housed at least partially in the dam structure, the guiding formations, the side walls and/or the secondary dam wall structure.
  • the power generating means may be housed in one or more an independent housings, the independent housings being positioned anywhere in the reservoir with the drainage ducting positioned such that the inlet delivers reservoir water to the power generating means and the outlet communicates water from the power generating means to the oncoming wave side of the body of water.
  • the intervals at which the drainage is positioned along the dam structure are typically functions of the volume of water to be drained as compared to the amount of water spilling into the reservoir, the dimensions of the drainage and the dimensions of power generating means.
  • the hydroelectric dam may include one or more modular ramp sections, the modular ramp sections being removably attachable to the dam structure so as to adjust the length and/or height of the ramp surface and dam structure respectively.
  • the modular ramp sections are removably attachable to the second reservoir side of the dam structure.
  • the reservoir water is capable of supplying water for a secondary use.
  • Exhaust water returning from the secondary use is drainable by secondary ducting connected to the drainage of the hydroelectric dam.
  • the secondary use is a desalination plant and the secondary ducting is connected to the drainage of the hydroelectric dam after the power generating means.
  • the dimensions of the dam structure and the depth at which it is positioned in the body of water are typically functions of one or more of at least the mean still water line of the body of water, the desired water level required in the reservoir, wave frequency, wave height and the height distribution of the relevant coastline.
  • the optimum depth at which the dam structure is constructible is between about 15 and 40 metres.
  • the optimum depth is between about 22 and 35 metres.
  • a dam structure for a hydroelectric dam having a first ramp side with an operatively lower front end, an operatively upper rear end and a parabolic ramp surface extending upwardly from the operatively lower front end to the operatively upper rear end of the first ramp surface.
  • the parabolic surface is defined by a parabola having an axis of symmetry substantially parallel with a horizontal plane and a focus point located above the operatively upper rear end of the first ramp side so as to in use reflect oncoming waves coming into contact with the parabolic ramp surface toward the focus point such that the waves ride upwardly and over the dam structure.
  • the focus point of the parabola is located rearwardly of the operatively upper rear end of the first ramp side, promoting the wave in use to ride upwardly and over the dam structure while reducing the possibility of a wave from breaking on the dam structure, thereby minimising damage thereto.
  • the parabola comprises a vertex, the vertex being located upwardly and rearwardly of the operatively upper rear end of the first ramp side.
  • the dam structure may comprise one or more guiding formations spaced in use apart from one another along the dam structure for at least partially guiding the oncoming waves correctly onto the first ramp side of the dam structure.
  • the guiding formations have at least one vertical wall extending between the operatively lower front and upper rear ends of the first ramp side of the dam structure.
  • the at least one vertical wall of the guiding formation is sloped or curved in the horizontal plane such that in use, the angle between the operatively upper rear end of the first ramp side and a line passing between points of contact of the vertical wall with the operatively upper rear and lower front ends of the first ramp side is substantially obtuse. More preferably, the at least one vertical wall of the guiding formation has a parabolic curvature with a secondary axis of symmetry substantially aiignable in use with the direction of the prevailing wave direction and with a secondary focus point located in use rearwardly of the operatively upper rear end of the first ramp side.
  • the guiding formation is wedge shaped having a thin edge positioned in use nearer the operatively lower front end of the first ramp side, a thicker end positioned in use nearer the operatively upper rear end of the first ramp side and vertical walls, sloped or curved, extending between the thin edge and the thicker end.
  • the dam structure and/or the guiding formations may define drainage ducts to in use drain water contained in the reservoir back to the oncoming wave side of the body of water. Furthermore, the dam structure and/or the guiding formations may define housing formations for housing means for generating power, the drainage ducts being in fluid communication with the housing formations for in use directing water draining from the reservoir into contact with the power generating means in order to drive the power generating means.
  • the dam structure comprises a second reservoir side having a height such that in use, the level of water contained in the reservoir is higher than a mean still water line of the body of water in which the dam structure is erected, providing sufficient pressure head to drive the power generating means.
  • the dam structure comprises one or more modular ramp sections, the modular ramp sections being removably attachable to the dam structure so as to adjust the length and/or height of the first ramp side of the dam structure. More preferably, the modular ramp sections are removably attachable to the second reservoir side of the dam structure.
  • the dam structure may be constructible in-situ or modularly.
  • a modularly constructible dam structure may comprise modular dam structure units and/or modular guiding formation units, the modular units being buoyant for the purpose of transportation and capable of being sunk into position during construction.
  • the body of water may be is from a group of bodies of water including the ocean, lakes, dams, rivers and other in-land waters.
  • Figure 1 is a schematic side view of a hydroelectric dam in accordance with the present invention.
  • Figure 2 is a schematic side view of the hydroelectric dam of figure 1 with the addition of a modular ramp section attached thereto;
  • Figure 3 is a schematic side view of a hydroelectric dam together with guiding formations mounted along the dam structure of the hydroelectric dam;
  • Figure 4 is a schematic plan view of the hydroelectric dam of figure 3;
  • Figure 5 is a schematic plan of a first alternative embodiment of a hydroelectric dam in accordance with the invention.
  • Figure 6 is a schematic plan of a second alternative embodiment of a hydroelectric dam in accordance with the invention.
  • Figure 7 is a schematic plan of a third alternative embodiment of a hydroelectric dam in accordance with the invention.
  • Figure 8 is a schematic plan of a fourth alternative embodiment of a hydroelectric dam in accordance with the invention.
  • Figure 9 is a side view of a dam structure unit for constructing a dam structure of a hydroelectric dam in accordance with the present invention. DETAILED DESCRIPTION OF THE DRAWINGS
  • a hydroelectric dam according to a preferred embodiment of the invention is designated generally with reference numeral 10 in figure 1.
  • the hydroelectric dam 10 comprises a dam structure 12, a reservoir 30 and a means for generating power 40.
  • the dam structure 12 is anchored to the floor 100 of a body of water, for example the seabed of a sea 102, such that a large portion thereof is submerged.
  • the dam structure 12 comprises a first ramp side 14 facing an oncoming wave side 104 of the sea 102 and a second reservoir side 16 facing the reservoir 30.
  • the first ramp side 14 comprises a ramp surface 18 extending between an operatively lower end 20 of the first ramp side 12 and an operatively upper end 22 thereof.
  • the ramp surface 18 is adapted to direct oncoming waves 104 upwardly and over the dam structure 12 to be captured and contained in the reservoir 30.
  • the ramp surface 18 may be linear, curved or any combination of the aforementioned, it is preferable that the ramp surface 18 is a parabolic curve partly defined by a parabola 24.
  • the parabola 24 has a axis of symmetry 26 being substantially parallel with a mean still water line 106 (MSWL) of the sea 102. Furthermore, the parabola 24 has a focus point 28 positioned above and further towards the reservoir side 30 of the hydroelectric dam 10 than the operatively upper end 22 of the first ramp side 14 of the dam structure 12. It will be appreciated that a vertex 29 of the parabola 24 is also positioned above and further towards the reservoir side 30 of the hydroelectric dam 10 than the operatively upper end 22 of the first ramp side 14 of the dam structure 12. It will be further appreciated that the use of the term "substantially" for the purposes of describing the orientation of one thing relative to another implies a deviation of between about 5 to 10 degrees.
  • the reservoir 30 into which the waves 04, spilling over the dam structure 20, are captured and contained is shaped and sized to contain a first volume of water "VV below the MSWL 106 of the sea 102 and a second volume of water “V 2 " above the MSWL 106 of the sea 102, which jointly define a common volume of water contained within the reservoir 30.
  • the power generating means 40 may be housed in the dam structure 12, together with drainage ducting 42, 44. Water draining from the reservoir 30 back to the sea 102 is directed into contact with the turbine 40 by an inlet duct 42, extending between the reservoir 30 and the turbine 40, and an outlet duct 44, extending between the turbine 40 and the sea 102.
  • the dam structure 12, built in-situ or modularly to form a hydroelectric dam 10 is orientation such that the first ramp side 14 is substantially perpendicular with the direction of the prevailing waves "D", and such that the axis of symmetry 26 of the parabola 24 is substantially parallel with the MSWL 106.
  • the MSWL represents the level of the sea, under normal conditions, if it were flat without any waves. It will be appreciated further that the relevant still water level coincides with a level approximately half way between the top of a wave crest and the bottom of a wave trough of a given set of waves.
  • Oncoming waves 104 travelling along the prevailing direction "D" and coming into contact with the dam structure 12 are redirected or reflected by the ramp surface 18 as depicted by directional arrows "D+".
  • the oncoming waves 104 are redirected or reflected upwardly along the ramp surface 18 towards the focus point 28 in accordance with generally accepted mathematical methodologies pertaining to parabolas.
  • the parabolic ramp surface 18 not only redirects or reflects oncoming waves 104 over the dam structure 12, but also acts to reduce the possibility of the oncoming waves 104 from breaking on the dam structure 12 causing damage thereto.
  • water from the reservoir 30 is drained from the reservoir 30 to the oncoming wave side 104 of the sea 102 via the inlet and outlet drainage ducts 42, 44.
  • the inlet of the inlet duct 42 is preferably spaced a distance away from the second reservoir side 16 of the dam structure 12 to minimise any turbulence effect on the inlet from the waves spilling over the dam structure 12, thereby ensuring efficient operation of the power generating means 40.
  • T e water draining through the drainage ducts 42, 44 is directed into contact with the power generating means 40, in the form of a turbine, so as to drive the turbine 40 and generate electrical power.
  • Drainage is aided by spacing the outlet end of the drainage duct 44 toward the oncoming wave side 104 by a distance from the first ramp side 14 of the dam structure 12 sufficient to minimise any interference effect from the oncoming waves 104.
  • the drainage is further aided by directing the outlet end of the outlet duct 44 in the same direction as a prevailing current in the sea 102 to aid drainage through a suction effect. Directing the outlet in the direction of the prevailing current also has the affect of further reducing any interference effect from the oncoming waves.
  • the second volume of water "V 2 " contained in the reservoir 30 provides the pressure head required to drive the turbine 40. Drainage of the reservoir 30 is controlled or designed in such a manner as to ensure that the volume of water spilling into the reservoir 30 is equal or greater than the volume of water drained therefrom. In this way, the second volume of water “V 2 " in retained in the reservoir 30, providing a pressure head for continuously driving the turbine 40.
  • the reservoir 30 is defined by the second reservoir side 16 of the dam structure 12, the seabed 100 and that portion of landmass 108 extending inland between an original shoreline 110 and a new shoreline 112.
  • the original shoreline 110 is representative of the original location of contact between the oncoming waves 104 and the landmass 108, i.e. prior to the construction of the hydroelectric dam 10.
  • the new shoreline is representative of the new location of contact between the water contained in the reservoir 30 and the landmass 108, i.e. after construction of the hydroelectric dam 10.
  • the hydroelectric dam 10 further comprises modular ramp sections 46, which are removably attachable to the dam structure to adjust the length of the ramp surface 18 and the height of the second reservoir side 16 of the dam structure 12.
  • a modular ramp section 46 With the addition of a modular ramp section 46, a higher level 48 of water is attainable in the reservoir 30 as compared to the level 49 of the reservoir 30 prior to the addition of the modular ramp section 46, taking into account a higher MSWL 106 caused by global warming.
  • the hydroelectric dam 10 may further include one or more guiding formations 50 spaced apart from one another along the dam structure 12, which at least partially guide the oncoming waves 104 correctly onto the first ramp side 14 of the dam structure 12 and there over.
  • the guiding formations 50 are wedge shaped having substantially vertical walls 52 extending between a thin edge 54 located proximate the operatively lower end 20 of the first ramp side 14 of the dam structure 12 and a thicker end 56 located proximate the operatively upper end 22 of the first ramp side 14 of the dam structure 12.
  • the vertical walls 52 may be sloped or curved in the horizontal plane to direct oncoming waves 104 towards the relevant spill zones 58 defined between adjacent guiding formations 50.
  • the vertical walls 52 have a parabolic curvature for directing the oncoming waves 104 toward a secondary focus point 60 located on the reservoir side 30 of the hydroelectric dam 10.
  • a turbine house 62 being integral with the guiding formations 50 or adjacent thereto is located proximate the thicker end 56 of the guiding formations 50. It will be appreciated that instead of housing the turbine 40 and the drainage ducting 42, 44 in the dam structure 12, it is possible to house the aforementioned in the turbine housing 62 and the guiding formations 50. Alternatively, the turbine house 62 could be positioned in the reservoir 30 spaced away from any constructed barrier defining the reservoir 30. In the alternative position of the turbine house 62, the inlet duct 42 is configured in any way to deliver reservoir water to the turbine 40 and the outlet duct 44 is configured in any way to communicated water from the turbine 40 to the oncoming wave side 104 of the sea 102.
  • the inlet duct 42 communicates draining reservoir water from the reservoir 30, through the turbine 40 and out towards the oncoming wave side 104 of the sea 102 via outlet duct 44 passing through the guiding formation 50.
  • the design of a required hydroelectric dam 10 depends on many factors such as:
  • MSWL mean still water line
  • hydroelectric dam 10 may take many other embodiments.
  • a hydroelectric dam 110 is constructible at sea (i.e. in deep water) having a dam structure 120 and a secondary dam wall structure 121 jointly forming a closed loop in which the reservoir 130 is defined.
  • the hydroelectric dam 110 in figure 5 is illustrated as having an elliptical shape, it will be appreciated that the hydroelectric dam 110 can take any shape.
  • a hydroelectric dam 210 is constructed at the mouth of a bay 211 , the closed bay 211 acting as a reservoir 230.
  • a hydroelectric dam 310 is staggered and angled with respect to the shore 14 such that the first ramp side 322 of the dam structure 320 is orientated in the direction "D" of the prevailing waves.
  • the preferred embodiment of the invention refers to a hydroelectric dam having a dam structure 12 spanning from a first location on a shore to a second location on the shore.
  • a hydroelectric dam 410 proximate the shore with the reservoir 430, as illustrated in figure 8, defined by the second reservoir side 416 of the dam structure 412, the landmass 108 and side walls 417 extending between the dam structure 412 and the landmass 108.
  • the turbine 40 may be housed in the side walls 417.
  • the turbine 40 may be housed in an independent turbine housing spaced away from any constructed barrier forming the reservoir 430, with the drainage ducting passing through the side wall(s) 417.
  • Figure 9 illustrates a dam structure unit 412, representing a section in a length of a dam structure 10 constructed in-situ.
  • the dam structure unit 412 represents a modular unit for constructing the dam structure 10 modularly.
  • the dam structure unit 412 comprises a first ramp side 414 for facing in use oncoming waves and a second reservoir side 416 for facing in use a reservoir formed behind the dam structure 10 constructed from the dam structure unit 412.
  • the first ramp side 414 of the dam structure unit 412 comprises an operatively lower front end 420, an operatively upper rear end 422 and a parabolic ramp surface 418 extending between the operatively lower front end 420 and the operatively upper rear end 422.
  • the parabolic ramp surface 418 is defined by a parabola 424 having a focus point 428 located upwardly and rearwardly of the operatively upper rear end 422 so as to redirect or reflect, in use, on coming waves upwardly and over the dam structure 10 constructed by the dam structure units 412.
  • hydroelectric dam can be employed in any body of water having waves.
  • the hydroelectric dam may be employed as a part of a larger system, for example, in a desalination system or pumped storage dam system or as protection to a harbour structure.

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  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
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  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)

Abstract

This invention relates to a dam structure and hydroelectric dam (10) construction therefrom. More specifically, the invention relates to an alternative energy source in the form of an oceanic hydroelectric dam (10) for converting the energy stored in sea waves to electrical power. The hydroelectric dam (10) includes a dam structure (12), a reservoir (30) and a means for generating power (10). The dam structure (12) is anchored to the floor (100) of the ocean and comprises a ramp adapted to direct oncoming waves upwardly and over the dam structure (10) to be collected in a reservoir (30). The power generating (40) means is driven by drainage of water collected in the reservoir (30) back to the ocaen, wherein the drainage of the reservoir is such that a sufficient level of water is retained therein to provide the necessary pressure head to continuously drive the power generating means (40).

Description

DAM STRUCTURE AND HYDROELECTRIC DAM CONSTRUCTION THEREFROM
FIELD OF THE INVENTION
THIS invention relates to a dam structure and hydroelectric dam construction therefrom. More specifically, the invention relates to an alternative energy source in the form of an oceanic hydroelectric dam for converting the energy stored in sea waves to electrical power.
BACKGROUND OF THE INVENTION
It is well known that the demand for electrical power world-wide is far out running supply. As a result, the cost of electricity has steadily increases over a number of years with no sign of abating.
In most countries, electricity is supplied by way of non-renewable resources such as coal, nuclear and natural gas. Only recently have some pioneering countries, in the view of being more environmentally friendly, turned to renewable resources in the form of solar, wind and water.
It will be appreciated that although technology exists for generating power from renewable resources, further development is required to make power generation from renewable resource cost effective. One major renewable resource is the energy contained in ocean waves. It is estimated that harnessing of 0.2 percent of the energy generated by ocean waves and currents is likely to fulfil the world's electricity demand.
Many technologies for harnessing the energy of waves for the purpose of generating power are known. One such technology utilises tethered buoys, which move up-and- down with the motion of the waves. The up-and-down motion of the buoys is then used to drive a generator, converting the energy of the waves into electrical power.
Another known technology is the adaptation of water wheels for oceanic purposes. Water wheels are, or were in the past, commonly used in water ways having flow in a single direction, for example a river. In the ocean, the intermittent nature of ocean waves makes the continuous turning of the water wheel very difficult and impractical.
Yet another known technology, as disclosed in United States patent 5,461 ,862 in the name of Ovadia S., utilises a channelling means for channelling ocean waves into a duct having hydraulic oil or air separated from the ocean water by a membrane, thereby converting the energy of the waves into a hydraulic oil or air pressure. This hydraulic oil or air pressure is then used to drive a hydraulic or pneumatic motor, thereby driving an electrical generator coupled thereto to generate electrical power. This technology is only operable in areas with relatively high waves, therefore making it unsuitable for use in many parts of the world.
Ramp type technologies as also known. The first of this type of technology is disclosed in United States patent 4,263,516 in the name of Papadakis, G.M., which utilises a ramp having a series of water channels in fluid communication with a water wheel. As a wave rides upwardly on the ramp, water falls under the force of gravity down the channels and onto the water wheel, thereby driving a generator coupled to the water wheel.
The second of this type of technology is disclosed in United States patent 1 ,922,055 in the name of Marx, K.F., which directs a wave upwardly on a ramp and into a holding tank at the top of the ramp. Drainage of the water from the holding tank back to the ocean is used to drive a generator set.
Although the aforementioned ramp type technologies attempt to provide a system for converting wave energy to electricity, both are practically flawed in that power can only be generated on a start-stop basis. With respect to US 4,263,516, power is only generated with a wave following up the structure. As such, no power generation occurs between subsequent waves. With respect to US 1 ,922,055, no power will be generated whilst the holding tank is being replenished with water from the waves.
Accordingly, it is an object of the present invention to provide a dam structure and a hydroelectric dam constructed therefrom that utilises the ocean waves to replenish a reservoir, which provides a pressure head to continuously drive a power generating device.
SUMMARY OF THE INVENTION
According to the invention there is provided a hydroelectric dam including: a dam structure anchored to the floor of a body of water and comprising a first ramp side and a second reservoir side, the first ramp side positioned to face the oncoming wave side of the body of water and adapted to direct the oncoming waves upwardly and over the dam structure; a reservoir into which the waves spilling over the dam structure are captured and contained, the reservoir being shaped and sized to contain a first volume of water below a mean still water line of the body of water and a second volume of water above the mean still water line of the body of water, the first and second volumes of water jointly defining a common volume of reservoir water; and means for generating power, the power generating means being driven by drainage of the reservoir water from the reservoir back to oncoming wave side of the body of water, wherein the second volume of water contained in the reservoir provides the pressure head required to drive the power generating means.
The reservoir is typically drained through drainage ducting comprising an inlet positioned in the reservoir and an outlet positioned in the oncoming wave side of the body of water. Generally, the drainage ducting is adapted to communicate the draining water to the power generating means between its passage from the inlet to the outlet. The inlet may be spaced a distance away from the second reservoir side to minimise any turbulence effect on the inlet from the waves spilling over the dam structure, thereby ensuring efficient operating of the power generating means. Preferably, the outlet is also spaced a distance away from the dam structure towards the oncoming wave side of the body of water to minimise any interference effect from the oncoming waves. Furthermore, the outlet may be directed in the same direction as a prevailing current in the body of water to aid drainage through a suction effect. Directing the outlet in the direction of the prevailing current also has the affect of further reducing any interference effect from the oncoming waves.
Preferably, the drainage of the reservoir is controlled or designed such that the volume of water spilling over the dam structure and into the reservoir is equal to or greater than the volume of water being drained from the reservoir, thereby maintaining the second volume of water and providing a pressure head for continuously driving the power generating means, the power generating means being one or more water driven turbines.
Generally, the reservoir is defined by at least the second reservoir side of the dam structure and the floor of the body of water to which the dam structure is anchored.
Where the hydroelectric dam is constructed proximate to a shore, the reservoir may be defined by the second reservoir side of the dam structure, the floor of the body of water to which the dam structure is anchored and that portion of landmass extending inland from an original shoreline on which the oncoming waves contacted land prior to the construction of the dam structure and a new shoreline on which the reservoir water contacts the land post construction of the dam structure. It will be appreciated that the new shoreline is at a higher sea level than the original shoreline.
In an alternative embodiment of a hydroelectric dam constructed proximate to the shore, the reservoir may be defined by the second reservoir side of the dam structure, the floor of the body of water to which the dam structure is anchored, side walls extending between the dam structure and the shore and that portion of landmass extending inland from an original shoreline on which the oncoming waves contacted land prior to the construction of the dam structure and a new shoreline on which the reservoir water contacts the land post construction of the dam structure.
Alternatively, where the hydroelectric dam is constructed in deep water in the body of water, the reservoir may be defined by the second reservoir side of the dam structure and the floor of the body of water to which the dam structure is anchored, the dam structure being constructed to form a closed loop. In yet an alternative deep dam embodiment, the reservoir may be defined by the second reservoir side of the dam structure, a secondary dam wall structure and the floor of the body of water to which the dam structure is anchored, the dam structure and secondary dam wall structure being constructed to jointly form a closed loop with the first ramp side of the dam structure facing the direction of the prevailing waves.
The first ramp side of the dam structure may comprise an operatively lower end, an operatively upper end and an upwardly directed sloped or curved ramp surface extending from the operatively lower end to the operatively upper end of the first ramp side.
Preferably, the first ramp side of the dam structure comprises an operatively lower end, an operatively upper end and an parabolic ramp surface extending upwardly from the operatively lower and end to the operatively upper end of the first ramp side. More preferably, the parabolic surface is defined by a parabola having an axis of symmetry substantially parallel with the mean still water line of the body of water and a focus point located above the operatively upper end of the first ramp side so as to reflect oncoming waves coming into contact with the parabolic ramp surface toward the focus point such that the waves ride upwardly and over the dam structure.
More preferably, the focus point of the parabola is located further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side, promoting the wave to ride upwardly and over the dam structure while reducing the possibility of a wave from breaking on the dam structure, thereby minimising damage thereto. Most preferably, the parabola comprises a vertex, the vertex being located above and further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side. Typically, the first ramp side of the dam structure is substantially perpendicular to the prevailing wave flow direction. Furthermore, the dam structure may be constructible in- situ or modularly. It will be appreciated that a modularly constructed dam structure is generally constructible by modular dam structure units, the modular dam structure units may be buoyant for the purpose of transportation and capable of being sunk into position during construction.
The hydroelectric dam may further comprise one or more guiding formations spaced apart from one another along the dam structure for at least partially guiding the oncoming waves correctly onto the first ramp side of the dam structure. Preferably, the guiding formations have at least one vertical wall extending between the operatively lower and upper ends of the first ramp side of the dam structure. More preferably, the at least one vertical wall of the guiding formation is sloped or curved in the horizontal plane such that the angle between the operatively upper end of the first ramp side and a line passing between points of contact of the vertical wall with the operatively upper and lower ends of the first ramp side is substantially obtuse. Preferably, the at least one vertical wall of the guiding formation has a parabolic curvature with a secondary axis of symmetry substantially in the direction of the prevailing wave direction and with a secondary focus point located further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side.
Most preferably, the guiding formation is wedge shaped having a thin edge positioned nearer the operatively lower end of the first ramp side, a thicker end positioned nearer the operatively upper end of the first ramp side and vertical walls, sloped or curved, extending between the thin edge and the thicker end. Even more preferably, the guiding formations are modular guiding formation units, the modular guiding formation units may be buoyant for the purpose of transportation and capable of being sunk into position during construction.
The drainage and/or the power generating means may be housed at least partially in the dam structure and/or the guiding formations. Alternatively, the drainage and/or the power generating means may be housed at least partially in the dam structure, the guiding formations, the side walls and/or the secondary dam wall structure. Alternatively, the power generating means may be housed in one or more an independent housings, the independent housings being positioned anywhere in the reservoir with the drainage ducting positioned such that the inlet delivers reservoir water to the power generating means and the outlet communicates water from the power generating means to the oncoming wave side of the body of water.
The intervals at which the drainage is positioned along the dam structure are typically functions of the volume of water to be drained as compared to the amount of water spilling into the reservoir, the dimensions of the drainage and the dimensions of power generating means.
The hydroelectric dam may include one or more modular ramp sections, the modular ramp sections being removably attachable to the dam structure so as to adjust the length and/or height of the ramp surface and dam structure respectively. Preferably, the modular ramp sections are removably attachable to the second reservoir side of the dam structure.
Generally, the reservoir water is capable of supplying water for a secondary use. Exhaust water returning from the secondary use is drainable by secondary ducting connected to the drainage of the hydroelectric dam. Preferably, the secondary use is a desalination plant and the secondary ducting is connected to the drainage of the hydroelectric dam after the power generating means.
It will be appreciated that the dimensions of the dam structure and the depth at which it is positioned in the body of water are typically functions of one or more of at least the mean still water line of the body of water, the desired water level required in the reservoir, wave frequency, wave height and the height distribution of the relevant coastline. Generally, the optimum depth at which the dam structure is constructible is between about 15 and 40 metres. Preferably, the optimum depth is between about 22 and 35 metres.
According to a second aspect of the invention, there is provided a dam structure for a hydroelectric dam, the dam structure having a first ramp side with an operatively lower front end, an operatively upper rear end and a parabolic ramp surface extending upwardly from the operatively lower front end to the operatively upper rear end of the first ramp surface. Generally, the parabolic surface is defined by a parabola having an axis of symmetry substantially parallel with a horizontal plane and a focus point located above the operatively upper rear end of the first ramp side so as to in use reflect oncoming waves coming into contact with the parabolic ramp surface toward the focus point such that the waves ride upwardly and over the dam structure.
Preferably, the focus point of the parabola is located rearwardly of the operatively upper rear end of the first ramp side, promoting the wave in use to ride upwardly and over the dam structure while reducing the possibility of a wave from breaking on the dam structure, thereby minimising damage thereto. More preferably, the parabola comprises a vertex, the vertex being located upwardly and rearwardly of the operatively upper rear end of the first ramp side.
Furthermore, the dam structure may comprise one or more guiding formations spaced in use apart from one another along the dam structure for at least partially guiding the oncoming waves correctly onto the first ramp side of the dam structure. Typically, the guiding formations have at least one vertical wall extending between the operatively lower front and upper rear ends of the first ramp side of the dam structure.
Preferably, the at least one vertical wall of the guiding formation is sloped or curved in the horizontal plane such that in use, the angle between the operatively upper rear end of the first ramp side and a line passing between points of contact of the vertical wall with the operatively upper rear and lower front ends of the first ramp side is substantially obtuse. More preferably, the at least one vertical wall of the guiding formation has a parabolic curvature with a secondary axis of symmetry substantially aiignable in use with the direction of the prevailing wave direction and with a secondary focus point located in use rearwardly of the operatively upper rear end of the first ramp side. Most preferably, the guiding formation is wedge shaped having a thin edge positioned in use nearer the operatively lower front end of the first ramp side, a thicker end positioned in use nearer the operatively upper rear end of the first ramp side and vertical walls, sloped or curved, extending between the thin edge and the thicker end. A dam structure according to any one of the preceding claims, wherein the dam structure is capable of being anchored to the floor of a body of water with the first ramp side orientated to face the oncoming wave side of the body of water such that the oncoming waves coming into contact with the dam structure in use are directed upwardly and over the dam structure into a reservoir defined behind the dam structure.
The dam structure and/or the guiding formations may define drainage ducts to in use drain water contained in the reservoir back to the oncoming wave side of the body of water. Furthermore, the dam structure and/or the guiding formations may define housing formations for housing means for generating power, the drainage ducts being in fluid communication with the housing formations for in use directing water draining from the reservoir into contact with the power generating means in order to drive the power generating means.
Generally, the dam structure comprises a second reservoir side having a height such that in use, the level of water contained in the reservoir is higher than a mean still water line of the body of water in which the dam structure is erected, providing sufficient pressure head to drive the power generating means.
Preferably, the dam structure comprises one or more modular ramp sections, the modular ramp sections being removably attachable to the dam structure so as to adjust the length and/or height of the first ramp side of the dam structure. More preferably, the modular ramp sections are removably attachable to the second reservoir side of the dam structure.
The dam structure may be constructible in-situ or modularly. A modularly constructible dam structure may comprise modular dam structure units and/or modular guiding formation units, the modular units being buoyant for the purpose of transportation and capable of being sunk into position during construction.
The body of water may be is from a group of bodies of water including the ocean, lakes, dams, rivers and other in-land waters. BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:
Figure 1 is a schematic side view of a hydroelectric dam in accordance with the present invention;
Figure 2 is a schematic side view of the hydroelectric dam of figure 1 with the addition of a modular ramp section attached thereto;
Figure 3 is a schematic side view of a hydroelectric dam together with guiding formations mounted along the dam structure of the hydroelectric dam;
Figure 4 is a schematic plan view of the hydroelectric dam of figure 3;
Figure 5 is a schematic plan of a first alternative embodiment of a hydroelectric dam in accordance with the invention;
Figure 6 is a schematic plan of a second alternative embodiment of a hydroelectric dam in accordance with the invention;
Figure 7 is a schematic plan of a third alternative embodiment of a hydroelectric dam in accordance with the invention; and
Figure 8 is a schematic plan of a fourth alternative embodiment of a hydroelectric dam in accordance with the invention.
Figure 9 is a side view of a dam structure unit for constructing a dam structure of a hydroelectric dam in accordance with the present invention. DETAILED DESCRIPTION OF THE DRAWINGS
A hydroelectric dam according to a preferred embodiment of the invention is designated generally with reference numeral 10 in figure 1. The hydroelectric dam 10 comprises a dam structure 12, a reservoir 30 and a means for generating power 40.
The dam structure 12 is anchored to the floor 100 of a body of water, for example the seabed of a sea 102, such that a large portion thereof is submerged. The dam structure 12 comprises a first ramp side 14 facing an oncoming wave side 104 of the sea 102 and a second reservoir side 16 facing the reservoir 30. The first ramp side 14 comprises a ramp surface 18 extending between an operatively lower end 20 of the first ramp side 12 and an operatively upper end 22 thereof.
The ramp surface 18 is adapted to direct oncoming waves 104 upwardly and over the dam structure 12 to be captured and contained in the reservoir 30. Although the ramp surface 18 may be linear, curved or any combination of the aforementioned, it is preferable that the ramp surface 18 is a parabolic curve partly defined by a parabola 24.
The parabola 24 has a axis of symmetry 26 being substantially parallel with a mean still water line 106 (MSWL) of the sea 102. Furthermore, the parabola 24 has a focus point 28 positioned above and further towards the reservoir side 30 of the hydroelectric dam 10 than the operatively upper end 22 of the first ramp side 14 of the dam structure 12. It will be appreciated that a vertex 29 of the parabola 24 is also positioned above and further towards the reservoir side 30 of the hydroelectric dam 10 than the operatively upper end 22 of the first ramp side 14 of the dam structure 12. It will be further appreciated that the use of the term "substantially" for the purposes of describing the orientation of one thing relative to another implies a deviation of between about 5 to 10 degrees.
The reservoir 30 into which the waves 04, spilling over the dam structure 20, are captured and contained is shaped and sized to contain a first volume of water "VV below the MSWL 106 of the sea 102 and a second volume of water "V2" above the MSWL 106 of the sea 102, which jointly define a common volume of water contained within the reservoir 30.
The power generating means 40, typically in the form of one or more water driven turbines, may be housed in the dam structure 12, together with drainage ducting 42, 44. Water draining from the reservoir 30 back to the sea 102 is directed into contact with the turbine 40 by an inlet duct 42, extending between the reservoir 30 and the turbine 40, and an outlet duct 44, extending between the turbine 40 and the sea 102.
In use, the dam structure 12, built in-situ or modularly to form a hydroelectric dam 10, is orientation such that the first ramp side 14 is substantially perpendicular with the direction of the prevailing waves "D", and such that the axis of symmetry 26 of the parabola 24 is substantially parallel with the MSWL 106. It will be appreciated that the MSWL represents the level of the sea, under normal conditions, if it were flat without any waves. It will be appreciated further that the relevant still water level coincides with a level approximately half way between the top of a wave crest and the bottom of a wave trough of a given set of waves.
Oncoming waves 104, travelling along the prevailing direction "D" and coming into contact with the dam structure 12 are redirected or reflected by the ramp surface 18 as depicted by directional arrows "D+". Where the ramp surface 18 is a parabolic ramp surface, the oncoming waves 104 are redirected or reflected upwardly along the ramp surface 18 towards the focus point 28 in accordance with generally accepted mathematical methodologies pertaining to parabolas. As the water making up the waves 104 clears the operatively upper end 22 of the first ramp side 14, it spills over into the reservoir 30. It will be appreciated that the parabolic ramp surface 18 not only redirects or reflects oncoming waves 104 over the dam structure 12, but also acts to reduce the possibility of the oncoming waves 104 from breaking on the dam structure 12 causing damage thereto.
To generate power, water from the reservoir 30 is drained from the reservoir 30 to the oncoming wave side 104 of the sea 102 via the inlet and outlet drainage ducts 42, 44. The inlet of the inlet duct 42 is preferably spaced a distance away from the second reservoir side 16 of the dam structure 12 to minimise any turbulence effect on the inlet from the waves spilling over the dam structure 12, thereby ensuring efficient operation of the power generating means 40.
T e water draining through the drainage ducts 42, 44 is directed into contact with the power generating means 40, in the form of a turbine, so as to drive the turbine 40 and generate electrical power. Drainage is aided by spacing the outlet end of the drainage duct 44 toward the oncoming wave side 104 by a distance from the first ramp side 14 of the dam structure 12 sufficient to minimise any interference effect from the oncoming waves 104. The drainage is further aided by directing the outlet end of the outlet duct 44 in the same direction as a prevailing current in the sea 102 to aid drainage through a suction effect. Directing the outlet in the direction of the prevailing current also has the affect of further reducing any interference effect from the oncoming waves.
The second volume of water "V2" contained in the reservoir 30 provides the pressure head required to drive the turbine 40. Drainage of the reservoir 30 is controlled or designed in such a manner as to ensure that the volume of water spilling into the reservoir 30 is equal or greater than the volume of water drained therefrom. In this way, the second volume of water "V2" in retained in the reservoir 30, providing a pressure head for continuously driving the turbine 40.
In the preferred embodiment of the hydroelectric dam 10, the reservoir 30 is defined by the second reservoir side 16 of the dam structure 12, the seabed 100 and that portion of landmass 108 extending inland between an original shoreline 110 and a new shoreline 112. The original shoreline 110 is representative of the original location of contact between the oncoming waves 104 and the landmass 108, i.e. prior to the construction of the hydroelectric dam 10. The new shoreline is representative of the new location of contact between the water contained in the reservoir 30 and the landmass 108, i.e. after construction of the hydroelectric dam 10.
Referring now to figure 2, and for the purposes of combating the effects of global warming, the hydroelectric dam 10 further comprises modular ramp sections 46, which are removably attachable to the dam structure to adjust the length of the ramp surface 18 and the height of the second reservoir side 16 of the dam structure 12. With the addition of a modular ramp section 46, a higher level 48 of water is attainable in the reservoir 30 as compared to the level 49 of the reservoir 30 prior to the addition of the modular ramp section 46, taking into account a higher MSWL 106 caused by global warming.
Referring now to figure 3 and figure 4, the hydroelectric dam 10 may further include one or more guiding formations 50 spaced apart from one another along the dam structure 12, which at least partially guide the oncoming waves 104 correctly onto the first ramp side 14 of the dam structure 12 and there over. In the preferred illustrated embodiment, the guiding formations 50 are wedge shaped having substantially vertical walls 52 extending between a thin edge 54 located proximate the operatively lower end 20 of the first ramp side 14 of the dam structure 12 and a thicker end 56 located proximate the operatively upper end 22 of the first ramp side 14 of the dam structure 12. The vertical walls 52 may be sloped or curved in the horizontal plane to direct oncoming waves 104 towards the relevant spill zones 58 defined between adjacent guiding formations 50. Preferably, the vertical walls 52 have a parabolic curvature for directing the oncoming waves 104 toward a secondary focus point 60 located on the reservoir side 30 of the hydroelectric dam 10.
A turbine house 62, being integral with the guiding formations 50 or adjacent thereto is located proximate the thicker end 56 of the guiding formations 50. It will be appreciated that instead of housing the turbine 40 and the drainage ducting 42, 44 in the dam structure 12, it is possible to house the aforementioned in the turbine housing 62 and the guiding formations 50. Alternatively, the turbine house 62 could be positioned in the reservoir 30 spaced away from any constructed barrier defining the reservoir 30. In the alternative position of the turbine house 62, the inlet duct 42 is configured in any way to deliver reservoir water to the turbine 40 and the outlet duct 44 is configured in any way to communicated water from the turbine 40 to the oncoming wave side 104 of the sea 102.
With the turbine 40 and the drainage ducting 42, 44 partly housed in the turbine housing 62 and the guiding formations 50, the inlet duct 42 communicates draining reservoir water from the reservoir 30, through the turbine 40 and out towards the oncoming wave side 104 of the sea 102 via outlet duct 44 passing through the guiding formation 50. The design of a required hydroelectric dam 10 depends on many factors such as:
• the level of the mean still water line (MSWL);
• the pressure head required to drive the turbines;
• the reservoir level required to produce the required pressure head;
• the average and maximum wave heights;
• the average and maximum wave frequencies;
• the volume of water entering and exiting the reservoir; and
• the depth of the water at which the structure is to be erected.
Although the invention has been described with reference to a preferred hydroelectric dam 10 constructed near a shore of the ocean, it is envisaged that the hydroelectric dam 10 may take many other embodiments.
With reference to figure 5, illustrating a first alternative embodiment of the invention, a hydroelectric dam 110 is constructible at sea (i.e. in deep water) having a dam structure 120 and a secondary dam wall structure 121 jointly forming a closed loop in which the reservoir 130 is defined. Although the hydroelectric dam 110 in figure 5 is illustrated as having an elliptical shape, it will be appreciated that the hydroelectric dam 110 can take any shape.
Referring now to figure 6, illustrating a second alternative embodiment of the invention, a hydroelectric dam 210 is constructed at the mouth of a bay 211 , the closed bay 211 acting as a reservoir 230. In yet a third embodiment of the invention, as illustrated in figure 7, a hydroelectric dam 310 is staggered and angled with respect to the shore 14 such that the first ramp side 322 of the dam structure 320 is orientated in the direction "D" of the prevailing waves.
It will be appreciated that the preferred embodiment of the invention refers to a hydroelectric dam having a dam structure 12 spanning from a first location on a shore to a second location on the shore. However, where the shore is substantially straight, it may be suitable to construct a hydroelectric dam 410 proximate the shore with the reservoir 430, as illustrated in figure 8, defined by the second reservoir side 416 of the dam structure 412, the landmass 108 and side walls 417 extending between the dam structure 412 and the landmass 108. In this embodiment, the turbine 40 may be housed in the side walls 417. Alternatively, the turbine 40 may be housed in an independent turbine housing spaced away from any constructed barrier forming the reservoir 430, with the drainage ducting passing through the side wall(s) 417.
Figure 9 illustrates a dam structure unit 412, representing a section in a length of a dam structure 10 constructed in-situ. Alternatively, the dam structure unit 412 represents a modular unit for constructing the dam structure 10 modularly. The dam structure unit 412 comprises a first ramp side 414 for facing in use oncoming waves and a second reservoir side 416 for facing in use a reservoir formed behind the dam structure 10 constructed from the dam structure unit 412.
The first ramp side 414 of the dam structure unit 412 comprises an operatively lower front end 420, an operatively upper rear end 422 and a parabolic ramp surface 418 extending between the operatively lower front end 420 and the operatively upper rear end 422. The parabolic ramp surface 418 is defined by a parabola 424 having a focus point 428 located upwardly and rearwardly of the operatively upper rear end 422 so as to redirect or reflect, in use, on coming waves upwardly and over the dam structure 10 constructed by the dam structure units 412.
Although the invention has been described above with reference to prefe ed embodiments, it will be appreciated that many modifications or variations of the invention are possible without departing from the spirit or scope of the invention. For example, although the invention has been described with reference to the sea, it will be appreciated that the hydroelectric dam can be employed in any body of water having waves. Furthermore, the hydroelectric dam may be employed as a part of a larger system, for example, in a desalination system or pumped storage dam system or as protection to a harbour structure.

Claims

1. A hydroelectric dam including: a dam structure anchored to the floor of a body of water and comprising a first ramp side and a second reservoir side, the first ramp side positioned to face the oncoming wave side of the body of water and adapted to direct the oncoming waves upwardly and over the dam structure; a reservoir into which the waves spilling over the dam structure are captured and contained, the reservoir being shaped and sized to contain a first volume of water below a mean still water line of the body of water and a second volume of water above the mean still water line of the body of water, the first and second volumes of water jointly defining a common volume of reservoir water; and means for generating power, the power generating means being driven by drainage of the reservoir water from the reservoir back to oncoming wave side of the body of water, wherein the second volume of water contained in the reservoir provides the pressure head required to drive the power generating means.
2. A hydroelectric dam according to claim 1, wherein the reservoir is drained through drainage ducting comprising an inlet positioned in the reservoir and an outlet positioned in the oncoming wave side of the body of water, the drainage ducting being adapted to communicate the draining water to the power generating means between its passage from the inlet to the outlet.
3. A hydroelectric dam according to claim 2, wherein the inlet is spaced a distance away from the second reservoir side to minimise any turbulence effect on the inlet from the waves spilling over the dam structure, thereby ensuring efficient operating of the power generating means
4. A hydroelectric dam according to claim 2 of claim 3, wherein the outlet is spaced a distance away from the hydroelectric dam towards the oncoming wave side of the body of water to minimise any interference effect from the oncoming waves.
5. A hydroelectric dam according to claim 4, wherein the outlet is directed in the same direction as a prevailing current in the body of water to: aid drainage through a suction effect; and/or further reduce any interference effect from the oncoming waves.
6. A hydroelectric dam according to any one of claims 2 to 5, wherein the drainage of the reservoir is controlled or designed such that the volume of water spilling over the dam structure and into the reservoir is equal to or greater than the volume of water being drained from the reservoir, thereby maintaining the second volume of water and providing a pressure head for continuously driving the power generating means, the power generating means being one or more water driven turbines.
7. A hydroelectric dam according to any one of claims 1 to 6, wherein the reservoir is defined by at least the second reservoir side of the dam structure and the floor of the body of water to which the dam structure is anchored.
8. A hydroelectric dam according to claim 7, wherein the hydroelectric dam is a dam constructed proximate to a shore, the reservoir being defined by the second reservoir side of the dam structure, the floor of the body of water to which the dam structure is anchored and that portion of landmass extending inland from an original shoreline on which the oncoming waves contacted land prior to the construction of the dam structure and a new shoreline on which the reservoir water contacts the land post construction of the dam structure.
9. A hydroelectric dam according to claim 7, wherein the hydroelectric dam is a dam constructed proximate to a shore, the reservoir being defined by the second reservoir side of the dam structure, the floor of the body of water to which the dam structure is anchored, side walls extending between the dam structure and the shore and that portion of landmass extending inland from an original shoreline on which the oncoming waves contacted land prior to the construction of the dam structure and a new shoreline on which the reservoir water contacts the land post construction of the dam structure.
10. A hydroelectric dam according to claim 8 or claim 9, wherein the new shoreline is at a higher sea level than the original shoreline.
11. A hydroelectric dam according to claim 7, wherein the hydroelectric dam is a dam constructed in deep water in the body of water, the reservoir being defined by the second reservoir side of the dam structure and the floor of the body of water to which the dam structure is anchored, the dam structure being constructed to form a closed loop.
12. A hydroelectric dam according to claim 7, wherein the hydroelectric dam is a dam constructed in deep water in the body of water, the reservoir being defined by the second reservoir side of the dam structure, a secondary dam wall structure and the floor of the body of water to which the dam structure is anchored, the dam structure and secondary dam wall structure being constructed to jointly form a closed loop with the first ramp side of the dam structure facing the direction of the prevailing waves.
13. A hydroelectric dam according to any one of claims 1 to 12, wherein the first ramp side of the dam structure comprises an operatively lower end, an operatively upper end and an upwardly directed sloped or curved ramp surface extending from the operatively lower end to the operatively upper end of the first ramp side.
14. A hydroelectric dam according to any one of claims 1 to 12, wherein the first ramp side of the dam structure comprises an operatively lower end, an operatively upper end and an parabolic ramp surface extending upwardly from the operatively lower and end to the operatively upper end of the first ramp side, the parabolic surface being defined by a parabola having an axis of symmetry substantially parallel with the mean still water line of the body of water and a focus point located above the operatively upper end of the first ramp side so as to reflect oncoming waves coming into contact with the parabolic ramp surface toward the focus point such that the waves ride upwardly and over the dam structure.
15. A hydroelectric dam according to claim 14, wherein the focus point of the parabola is located further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side, promoting the wave to ride upwardly and over the dam structure while reducing the possibility of a wave from breaking on the dam structure, thereby minimising damage thereto.
16. A hydroelectric dam according to claim 14 or claim 15, wherein the parabola comprises a vertex, the vertex being located above and further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side.
17. A hydroelectric dam according to any one of claims 1 to 16, wherein the first ramp side of the dam structure is substantially perpendicular to the prevailing wave flow direction.
18. A hydroelectric dam according to any one of claims 1 to 17, wherein the dam structure is constructible in-situ or modularly.
19. A hydroelectric dam according to claim 17, wherein a modularly constructed dam structure is constructible by modular dam structure units, the modular dam structure units being buoyant for the purpose of transportation and capable of being sunk into position during construction.
20. A hydroelectric dam according to any one of claims 1 to 19, wherein the hydroelectric dam further comprises one or more guiding formations spaced apart from one another along the dam structure for at least partially guiding the oncoming waves correctly onto the first ramp side of the dam structure.
21. A hydroelectric dam according to claim 20, wherein the guiding formations have at least one vertical wall extending between the operatively lower and upper ends of the first ramp side of the dam structure.
22. A hydroelectric dam according to claim 21, wherein the at least one vertical wall of the guiding formation is sloped or curved in the horizontal plane such that the angle between the operatively upper end of the first ramp side and a line passing between points of contact of the vertical wall with the operatively upper and lower ends of the first ramp side is substantially obtuse.
23. A hydroelectric dam according to claim 22, wherein the at least one vertical wall of the guiding formation has a parabolic curvature with a secondary axis of symmetry substantially in the direction of the prevailing wave direction and with a secondary focus point located further towards the reservoir side of the hydroelectric dam than the operatively upper end of the first ramp side.
24. A hydroelectric dam according to claim 22 or claim 23, wherein the guiding formation is wedge shaped having a thin edge positioned nearer the operatively lower end of the first ramp side, a thicker end positioned nearer the operatively upper end of the first ramp side and vertical walls, sloped or curved, extending between the thin edge and the thicker end.
25. A hydroelectric dam according to any one of claims 20 to 24, wherein the guiding formations are modular guiding formation units, the modular guiding formation units being buoyant for the purpose of transportation and capable of being sunk into position during construction.
26. A hydroelectric dam according to any one of claims 20 to 25, wherein the drainage and/or the power generating means are housed at least partially in the dam structure and/or the guiding formations.
27. A hydroelectric dam according to any one of claims 19 to 25 read together with claim 8, wherein the drainage and/or the power generating means are housed at least partially in the dam structure, the guiding formations and/or the side walls.
28. A hydroelectric dam according to any one of claims 19 to 25 read together with claim 11 , wherein the drainage and/or the power generating means are housed at least partially in the dam structure, the guiding formations and/or the secondary dam wall structure.
29. A hydroelectric dam according to any one of claims 19 to 25, wherein the power generating means is housed in one or more independent housings, the independent housings being positioned anywhere in the reservoir with the drainage ducting positioned such that the inlet delivers reservoir water to the power generating means and the outlet communicates water from the power generating means to the oncoming wave side of the body of water.
30. A hydroelectric dam according to any one of claims 26 to 29, wherein the intervals at which the drainage is positioned along the dam structure are functions of the volume of water to be drained as compared to the amount of water spilling into the reservoir, the dimensions of the drainage and the dimensions of power generating means.
31. A hydroelectric dam according to any one of claims 1 to 30, including one or more modular ramp sections, the modular ramp sections being removably attachable to the dam structure so as to adjust the length and/or height of the ramp surface and dam structure respectively.
32. A hydroelectric dam according to claims 31, wherein the modular ramp sections are removably attachable to the second reservoir side of the dam structure.
33. A hydroelectric dam according to any one of claims 1 to 32, wherein the reservoir water is capable of supplying water for a secondary use, exhaust water returning from the secondary use is drainable by secondary ducting connected to the drainage of the hydroelectric dam.
34. A hydroelectric dam according to claim 33, wherein the secondary use is a desalination plant and the secondary ducting is connected to the drainage of the hydroelectric dam after the power generating means.
35. A hydroelectric dam according to any one of claims 1 to 34, wherein the dimensions of the dam structure and the depth at which it is positioned in the body of water are functions of one or more of at least the mean still water line of the body of water, the desired water level required in the reservoir, wave frequency, wave height and the height distribution of the relevant coastline.
36. A hydroelectric dam according to claim 35, wherein the optimum depth at which the dam structure is constructible is between about 15 and 40 metres.
37. A hydroelectric dam according to claim 36, wherein the optimum depth at which the dam structure is constructible is between about 22 and 35 metres.
38. A hydroelectric dam according to any one of claims 1 to 37, wherein the body of water is from a group of bodies of water including the ocean, lakes, dams, rivers and other in-land waters.
39. A dam structure for a hydroelectric dam, the dam structure having a first ramp side with an operatively lower front end, an operatively upper rear end and a parabolic ramp surface extending upwardly from the operatively lower front end to the operatively upper rear end of the first ramp surface, the parabolic surface being defined by a parabola having an axis of symmetry substantially parallel with a horizontal plane and a focus point located above the operatively upper end of the first ramp side so as to in use reflect oncoming waves coming into contact with the parabolic ramp surface toward the focus point such that the waves ride upwardly and over the dam structure.
40. A dam structure according to claim 39, wherein the focus point of the parabola is located rearwardly of the operatively upper rear end of the first ramp side, promoting the wave in use to ride upwardly and over the dam structure while reducing the possibility of a wave from breaking on the dam structure, thereby minimising damage thereto.
41. A dam structure according to claim 39 or claim 40, wherein the parabola comprises a vertex, the vertex being located upwardly and rearwardly of the operatively upper rear end of the first ramp side.
42. A dam structure according to any one of claims 39 to 41 , wherein the dam structure comprises one or more guiding formations spaced in use apart from one another along the dam structure for at least partially guiding the oncoming waves correctly onto the first ramp side of the dam structure.
43. A dam structure according to claims 42, wherein the guiding formations have at least one vertical wall extending between the operatively lower and upper ends of the first ramp side of the dam structure.
44. A dam structure according to claims 43, wherein the at least one vertical wall of the guiding formation is sloped or curved in the horizontal plane such that in use, the angle between the operatively upper end of the first ramp side and a line passing between points of contact of the vertical wall with the operatively upper and lower ends of the first ramp side is substantially obtuse.
45. A dam structure according to claim 44, wherein the at least one vertical wall of the guiding formation has a parabolic curvature with a secondary axis of symmetry substantially alignable in use with the direction of the prevailing wave direction and with a secondary focus point located in use rearwardly of the operatively upper rear end of the first ramp side.
46. A dam structure according to claims 44 or claim 45, wherein the guiding formation is wedge shaped having a thin edge positioned in use nearer the operatively lower end of the first ramp side, a thicker end positioned in use nearer the operatively upper end of the first ramp side and vertical walls, sloped or curved, extending between the thin edge and the thicker end.
47. A dam structure according to any one of the preceding claims, wherein the dam structure is capable of being anchored to the floor of a body of water with the first ramp side orientated to face the oncoming wave side of the body of water such that the oncoming waves coming into contact with the dam structure in use are directed upwardly and over the dam structure into a reservoir defined behind the dam structure.
48. A dam structure according to claim 47, wherein the dam structure and/or the guiding formations define drainage ducts to in use drain water contained in the reservoir back to the oncoming wave side of the body of water.
49. A dam structure according to claim 48, wherein the dam structure and/or the guiding formations further define housing formations for housing means for generating power, the drainage ducts being in fluid communication with the housing formations for in use directing water draining from the reservoir into contact with the power generating means in order to drive the power generating means.
50. A dam structure according to claim 49, wherein the dam structure comprises a second reservoir side having a height such that in use, the level of water contained in the reservoir is higher than a mean still water line of the body of water in which the dam structure is erected, providing sufficient pressure head to drive the power generating means.
51. A dam structure according to claim 50, wherein the dam structure comprises one or more modular ramp sections, the modular ramp sections being removably attachable to the dam structure so as to adjust the length and/or height of the first ramp side of the dam structure.
52. A dam structure according to claim 51, wherein the modular ramp sections are removably attachable to the second reservoir side of the dam structure.
53. A dam structure according to any one of claims 39 to 52, wherein the dam structure is constructible in-situ or modularly.
54. A dam structure according to claim 53, wherein a modularly constructible dam structure comprises modular dam structure units and/or modular guiding formation units, the modular units being buoyant for the purpose of transportation and capable of being sunk into position during construction.
55. A dam structure according to any one of claims 39 to 54, wherein the body of water is from a group of bodies of water including the ocean, lakes, dams, rivers and other in-land waters.
56. A hydroelectric dam substantially as herein described and illustrated.
57. A dam structure for a hydroelectric dam substantially as herein described and illustrated.
PCT/ZA2011/000017 2010-03-30 2011-03-29 Dam structure and hydroelectric dam construction therefrom WO2011123871A1 (en)

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WO2014115135A1 (en) * 2013-01-23 2014-07-31 Jubran Emad A wave energy converter and converting method
WO2015009134A1 (en) * 2013-07-17 2015-01-22 Zaldívar Velázques Carlos Eduardo System for generating electrical energy, based on an artificial reef
FR3026146A1 (en) * 2014-09-22 2016-03-25 Patrice Christian Philippe Charles Chevalier CONTINUOUS GENERATION GENERATOR MARINE DIGUE AND ASSOCIATED METHODS

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Patent Citations (1)

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Publication number Priority date Publication date Assignee Title
US2820148A (en) * 1957-03-18 1958-01-14 John W Southwick Wave motor and associated mechanism

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014115135A1 (en) * 2013-01-23 2014-07-31 Jubran Emad A wave energy converter and converting method
WO2015009134A1 (en) * 2013-07-17 2015-01-22 Zaldívar Velázques Carlos Eduardo System for generating electrical energy, based on an artificial reef
FR3026146A1 (en) * 2014-09-22 2016-03-25 Patrice Christian Philippe Charles Chevalier CONTINUOUS GENERATION GENERATOR MARINE DIGUE AND ASSOCIATED METHODS

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MA34180B1 (en) 2013-04-03
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