Power generation using a variable height water turbine

FIELD OF THE INVENTION

The present invention relates to the use of sea waves for pollution-free power generation.

More particularly, the invention provides a long channel in which water from waves enters and forms an artificial river, the flow therefrom driving a variable-height water turbine. The device gains efficiency by optimizing water flow geometry both in the inlet and the outlet of said turbine.

The mechanical energy generated by the turbine(s) can be used for the generation of electric power. However where water is required inland - for example for use of a desalination plant - the mechanical energy is used directly by a water pump and the conversion to and from electric power is eliminated.

The present specification is an improvement on and a development of my earlier patent Israel 180052, application date 14/12/2006.

While the primary application of the present invention is to utilize sea waves, the device can also be used at the side of a river or lake.

BACKGROUND OF THE INVENTION

Today there is general, although not universal acceptance of the world warming theory holding that gasses such as carbon dioxide which are released as a result of the burning of fossil fuels have a greenhouse effect when penetrated by solar radiation, causing an undesirable increase in world average temperatures. Furthermore there is a growing realization that fossil fuels, which are non-renewable will be exhausted within one generation even if consumption thereof continues only at the present rate, even though previous forecasts of the early exhaustion of fossil fuels have proved to be far too pessimistic. Consequently advanced countries are presently running programs to reduce reliance on fossil fuels (except natural gas) and replace them by generating energy from alternative renewable sources such as wind, solar, nuclear, and geothermal heat. Energy from sea waves has been exploited only to a very limited extent, presumably because known devices have not performed well relative to their cost. Energy produced by renewable sources is certain to remain in high demand as nuclear generating plants are closed and few new plants opened following the disaster in March 2011 at the nuclear power plant in Fukushima Daiichi, Japan.

Research in nuclear fusion is progressing but practical power generation is still 20 - 40 years away.

A known system for power generation, an example of which is seen in JP8177709 comprises a water turbine which rests on the sea surface and is attached to a vertical slide or to a pivoted lever. It is expensive and difficult to make such devices very long, as would be required to generate economically significant quantities of power. Thus a large number of such devices would need to be installed to make any impact on energy supplies. The devices also have a poor appearance as they protrude too far on the view of the sea.

Devices which collect water from sea waves and are intended to flush a secondary body of water could possibly be used also for power generation while returning the water to sea level. Such a device for clearing sand and other debris is disclosed by Andrews in US Patent no. 4,332,506. This device comprises a wave-and-tide-pump apparatus, which is based on the use of two wedge-like shapes which are entered by incoming waves. Were this device to be made very wide, the wedges would lose all effect. Therefore a large number of such devices would need to be installed side by side if a useful quantity of electricity is to be generated. Such an arrangement would be too expensive to be of use in generating power from sea waves, and would have a detrimental appearance.

In US 1,922,055 Marx disclosed a Hydroelectric Generator which collects water from high waves only. The water is collected in a high channel and piped down to a water turbine. Much of the kinetic energy of the water flow in the channel is lost as the water flows through several bends. Performance will be further degraded as incoming waves enter the turbine discharge pipe. Waves of moderate size are not utilized in this design.

A Breakwater and Power Generator is seen in US Patent 4,263,516 to Papadakis. This design has the advantage of collecting water also from smaller waves. The major problem with any wave power generator of this type lies in the intermittent nature of the waves. This design also has further drawbacks: the turbine is buried in a large concrete body providing little access for maintenance work. The narrow water entry channels are liable to blockages and the delicate channel dividers are liable to breakage.

For best results in areas affected by tidal changes in water level, the turbine(s) should operate at a height related to the prevalent water level.

There are several ways in which this can be achieved:

1. Floating the whole device, as proposed by Chase in US Patent 1,507,461

2. Supporting the whole device on wheels and rails, and pull/push it as required nearer/further relative to the shore, as proposed by Sherrard in US Patent 3,983,404. To move such a large and heavy item is difficult and derailment is likely.

3. Use totally immersed turbines while yet suspending said turbines on a vertical movement mechanism, as seen FR2878000 to Boisneau and GB2348250 to Fraenkel.

4. Use large hydraulic cylinders for lifting the turbine, and a control mechanism and a sea-water level detection device as proposed by Tomishirou in JP58160581.

5. Use an electrically driven dam.

6. A further method to be disclosed in a preferred embodiment of the present invention.

To change the present situation of miniscule utilization of wave energy there must be available an improved system for using waves both large and small, and providing water flow to the turbine at a rate which is reasonably consistent. The turbine and water geometry must be arranged for highest possible efficiency. Furthermore the system must be capable of expansion sufficiently to generate economically realistic quantities of electric power.

Meeting all these requirements is the object of the present invention, which aims to obviate the disadvantages of prior art methods of capturing wave energy.

The low efficiency of prior art devices has its roots in the water flow in the vicinity of the turbines. In some designs, e.g. GB2348250 some of the water flow does nothing to drive the turbine but escapes from its sides. Furthermore, turbine efficiency is much lower than would be possible because the turbine discharges water into water instead of into air. Prior art devices do not have a moving dam plate which carries the turbine to a desired height.

It is therefore one of the objects of the present invention to obviate the disadvantages of prior art and to provide a turbine device having improved efficiency by directing all the captured higher level water through a water turbine.

It is a further object of the present invention to ensure that turbine discharges freely into air and undisturbed by water from any other source.

The present invention achieves the above objects by providing a device wherein water flow along said extended length channel forms an artificial river, said device comprising * a channel provided with a shore-facing wall and a sea-facing side walls both extending substantially above said higher water level, said sea-facing side wall being pierced by at least one horizontal row of one-way apertures, a proximate end wall forming a fixed lower dam lower than said lower water level;

* an extended length floor plate attached to said walls preventing the escape of water under said walls;

* a vertically movable upper dam and turbine support in sliding contact with said proximate end wall forming a fixed lower dam, said vertically movable upper dam and turbine support being retained in a pair of vertical slide guide members, said vertically movable upper dam and turbine support preventing the exit of water from said extended length channel while allowing water flow through said at least one turbine carried by said support plate;

* said at least one turbine, arranged to be driven by water flowing from inside said channel, said at least one turbine being supported at a variable height at which the water held in said channel contacts at least part of the inner side of said turbine while the outer side of said turbine freely discharges water into air at a level above the water level on the outside of said extended length channel; and * an electric generator connected to be driven by each turbine.

In a preferred embodiment of the present invention there is provided a device further provided with counterweights operatively connected by tension members to said vertically movable upper dam and turbine support, said counterweights supporting most of the weight of said vertically movable upper dam and turbine support including turbine(s) carried thereby. There is further provided a float member operatively attached to said vertically movable upper dam and turbine support, said float member automatically retaining said turbine at a height slightly above the water level proximate to the turbine discharge,

In another preferred embodiment of the present invention there is provided a device wherein said one-way apertures are closed by a hinged shutter unit, said shutter unit opening inwards under pressure of sea waves and closing after the entry of said waves to maintain the water level in said channel.

In a further embodiment of the device said vertically movable upper dam and turbine support is positioned in a side wall.

In another preferred embodiment of the present invention there is provided a device further provided with a long ramp structure having an upper surface sloping in a vertical plane, said surface having an upper edge and a lower edge, said upper edge being above sea level adjacent and parallel to said sea-facing side wall, and said lower edge being below sea level, said ramp structure receiving waves flowing towards the shore and facilitating upward flow of said waves to flow Into said open-top long channel, thereby further raising the water level in said long channel above sea level.

In another preferred embodiment of the present invention there is provided a device as claimed in claim 1 further provided with counterweights operatively connected by tension members to said vertically movable upper dam and turbine support , said counterweights supporting most of the weight of said vertically movable upper dam and turbine support including turbine(s) carried thereby.

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Preferably a float member is operatively attached to said vertically movable upper dam and turbine support, said float member automatically retaining said turbine at a height slightly above the water level proximate to the turbine discharge.

In a preferred embodiment of the present invention said one-way apertures extend substantially over the complete area of said sea-facing wall.

In a most preferred embodiment of the present invention there is provided a device with a dam element positioned near the turbine outlet, said dam element extending to below sea level and preventing sea waves from reaching and disturbing free flow from the turbine outlet(s).

Alternative methods of lifting/lowering the dam plate involve the use of hydraulic cylinders and another method using an electric drive.

In a further preferred embodiment of the device said turbine(s) is/ are vertical-axis helical water wheels

The vertical movement of the turbine and the vertical dam plate supporting same enable the device of the present invention to operate with efficiently whether due to tidal changes or to the sea level is high or low. The turbine(s) will continue to operate with the lower portion of the turbine at or near sea level. All the water is directed to the turbine(s) by the moving dam plate which carries the turbine and positions same to discharge water into the air slightly above sea level.

It will thus be realized that the novel device of the present invention provides the basic features which serve to make possible economic power generation. The cost of the produced electricity will still be economic even if this cost is somewhat higher than electricity produced by present day power stations as there will be no pollution, no radiation dangers and no health risks of the type common in coal mining or in the operation of oil wells.

It is also important to realize that as the water flows in a straight line along the extended length channel to enter the turbine, the kinetic energy of the water is utilized to turn the turbine in addition to the potentiaf energy generated by the height difference between the raised water level in the channel (or artificial river) and the level of the sea, lake or river receiving the turbine discharge. This height difference is seen most clearly in FIG. 2.

With regard to the embodiment seen in FIG. 9 where the turbine is suspended in a side wall and the channel needs to discharge through a 90° bend, a curved water flow deflector (not seen) can be inserted to retain a good proportion of the kinetic energy of the water flowing along the channel towards the turbine(s).

In the preferred embodiment seen in FIG. 13 it is seen that the sea-facing wall of the long channel is provided with one-way windows both above and below seas level. This configuration allows free entry of large waves, the water thereof being retained inside the long channel to increase the water level therein and thus the force of the water impacting and driving the turbine.

The invention will now be described further with reference to the accompanying drawings, which represent by example preferred embodiments of the invention. Structural details are shown only as far as necessary for a fundamental understanding thereof, The described examples, together with the drawings, will make apparent to those skilled in the art how further forms of the invention may be realized.

In the drawings:

FIGS. 1a and 1b are perspective views of a preferred embodiment of the device for collecting energy from waves according to the invention, the turbine being seen in its lower position in FIG. 1a and in its upper position in FIG. 1b;

FIG. 2 is a detail view showing suspension of the moving plate carrying the turbine;

FIG. 3 is a fragmented cross-section of an embodiment provided with a ramp structure for inducing waves to enter the channel through the higher apertures;

FIG. 4 is a detail view of one of the one-way apertures for incoming waves;

FIG. 5 is a non-detailed perspective view of an embodiment provided with a dam plate protecting the turbine outlets;

FIG. 6 is a plan view of an embodiment disposed at an angle to the shore;

FIG.7 is an end view of a hydraulically operated dam plate

FIG 8 is an end view of an electrically operated dam plate;

. FIG. 9 is a pictorial non-detailed view of a device wherein the turbine and dam are disposed in a side of the long channel;

FIG. 10 is a perspective view of an embodiment wherein driven turbine is a paddle wheel having a horizontal axis disposed at 90 degrees to the direction of water flow;

FIG 11 is a non-detailed perspective view of the device;

FIG.12 is a perspective view of an embodiment wherein the water paddle wheel is mounted on a vertical axis, and

FIG. 13 is a perspective view of an embodiment wherein the shore-facing wall of the long channel is sloped relative to the vertical plane.

There is seen in FIGS. 1a and 1b a device for collecting energy from sea waves 10 flowing towards a shore 12. Water flows along the extended length channel 14 and forms an artificial river 32 above sea level 44.

The channel 14 is provided with a shore-facing side wall 16 and a sea-facing side wall

18. Both walls 16, 18 extend substantially above sea level 44. The sea-facing side wall 18 is pierced by several horizontal rows of one-way apertures 34 closed by shutter plates 30 seen more clearly in FIG. 4. The channel 14 terminates in a proximate end wall forming a fixed lower dam 22 slightly lower than the lowest sea level.

Preferably the one-way apertures 34 extend substantially over the complete area of the sea-facing side wall 18

A floor plate 24 is attached to the walls 16, 18 and to the fixed lower dam 22 and prevents the escape of water thereunder.

A vertically movable upper dam and turbine support 20 is in sliding contact with the fixed lower dam 22. The dam plate 20 prevents the exit of water from the extended length channel 14 while allowing water flow through the water turbine 28 carried by the support plate 20 in an aperture 26.

The turbine support 20 is retained in a pair of vertical slide guide members 26.

Also carried by the vertically movable upper dam and turbine support 20 is an electric generator 42. While the generator 42 could be co-axially coupled to the turbine 28 the generator 42 as seen is substantially protected from water and is better accessible for servicing in the position shown. The belt or chain drive 38 allows the generator 42 to be driven at a desired speed other than the speed of the turbine 28.

The vertically movable upper dam and turbine support plate 20 is shown in a lower position in FIG.1a and in a higher position in FIG. 1b.

A preferred arrangement for raising and lowering the plate will be described with reference to FIG. 2, the preferred arrangement being automatic, low-cost and requiring no electric power. Other methods of raising/lowering the plate 20, for example using hydraulic cylinders or an electrically driven system will be seen in FIGS. 7 and 8.

With reference to the rest of the figures, similar reference numerals have been used to identify similar parts.

Referring now to FIG. 2, there is seen a detail of a device for collecting energy from sea waves 10 further provided with at least one counterweight 40. In the present embodiment there is seen one counterweight 40 near each of the two edges of the plate 20 operatively connected by tension members 46 to the vertically movable upper dam and turbine support 20. The tension members 46 extend around pulleys 48 and support most of the weight of the vertically movable upper dam and turbine support 20 including all items carried thereby. Pulley support posts 52 are seen supported by the proximate end wall forming a fixed lower dam 22.

A float member 50 is operatively attached to the vertically movable upper dam and turbine support 20. The float member 50 automatically retains the turbine 28 at a height slightly above sea water level 44, thus allowing the turbine 28 free discharge into air.

FIG. 3 illustrates a detail of a further device for collecting energy from sea waves 10 further provided with a long ramp structure 54. The ramp structure 54 has an upper surface 56 sloping in a vertical plane, which surface 56 has an upper edge 58 and a lower edge 60. The upper edge 58 is above sea level 44 adjacent and parallel to the sea-facing side wail 18 of the extended length channel 14. The lower edge 60 is below sea level 44, allowing the ramp structure 54 to receive waves 10 flowing towards the shore 12 seen in FIG. 1a. The ramp 54 facilitates upward flow of the waves 10 to flow through the one-way apertures 34 into the channel 14, thereby further raising the water level 32 therein. The ramp structure 54, and the channel 14 are seen supported by pillars 62, 64 from the sea bottom 66.

Seen in FIG. 4 is a further detail of the device, showing one of the one-way apertures 34 as viewed from inside the wall 18 looking seawards. The apertures 34 are normally closed by the water pressure inside the extended length channel 14 acting on the shutter plates 30. Gravity provides a further force urging the shutter plates to close. The plates 30 are suspended by hinges 68 which allow the shutter plate 30 to open inwards when impacted by a wave 10 as seen in the figure. A stop element 70 prevents the shutter plate 30 from opening outwards, from opening outwards by a stop 70.

As seen in FIG. 5 the device can advantageously be further provided with a dam element 72 positioned near the turbine outlets. The dam element 72 extends to below sea level 44 and prevents sea waves 10 from reaching and disturbing free flow from the turbine 28 outlets. In the present embodiment the vertically movable upper dam and turbine support 20 carries three side by side turbines 28.

FIG. 6 shows an embodiment of the device wherein the longitudinal axis AA of the extended length channel 14 is positioned in the horizontal plane at an angle to the shore line 12. This orientation evens out the time of entry of successive waves 10 and thus reduces undesirable speed variations of the turbine 28.

FIG. 7 illustrates a device for hydraulic operation of the upper dam 74 supporting 3 turbines 86.

A vertically movable upper dam and turbine support plate 74 is lifted by two hydraulic cylinders 76 rigidly attached to a pair of guide members 78. A hydraulic/electric controller 80 receives signals from a sea level sensor 82. The controller is programmed to operate the hydraulic pump 84 to maintain the turbines 86 at a height just above sea level 88. The pump 84 receives oil from a reservoir 94 and forces said oil into the lower port 90 of the cylinders 76 to lift the turbines 86 as sea level 88 rises while expelling oil or air from the upper cylinder ports 92.

As sea level 88 drops, the controller 80 allows some of the oil to return via the lower port 90 to the reservoir 94, whereby gravity allows the movable upper dam and turbine support plate 74 to drop as required to maintain the desired height of the turbines 86 just above sea level 88.

To simplify the drawing the extended length channel 14 and the fixed lower dam 22 seen in FIG. 1 are not shown in the present figure.

FIG. 8 illustrates a device for electric operation of the upper dam 96 supporting 3 turbines 86.

A vertically movable upper dam and turbine support plate 96 is lifted and lowered by two spaced apart screws 98 driven through a chain or belt 108 by a reversible geared electric motor 100 rigidly attached to one of the guide members 78. The screws 98 engage nuts 106 attached to the plate 96. An electronic controller 102 receives signals from a sea level sensor 104. The controller 102 is programmed to use this data to operate the motor 100 to maintain the turbines 86 at a height just above sea level 88.

To simplify the drawing the extended length channel 14 and the fixed lower dam 22 seen in FIG. 1 are again omitted in the present figure.

In FIG. 9 there is seen a device 116 for collecting energy wherein the vertically movable upper dam and turbine support 20 are positioned in a side wall 16. This could be advantageous as turbine discharge 112 is directed at calmer water 114 between the long channel 14 and the shore 12. The calmer water 114 provides less disturbance to the turbine discharge 112 and thus raises the efficiency of the turbine 28.

The embodiment seen in FIG. 10 is a device 120 for collecting energy from sea waves 10 wherein the driven component is a paddle wheel 122 revolvably suspended in a vertically-movable upper dam plate 124, which is in sliding contact with a fixed lower dam 126. The two dam plates 124, 126 in combination prevent the exit of water from the extended length channel 14 while allowing water flow only through the lower portion of the paddle wheel 122.

The vertically־movable upper dam plate 124 is retained in a pair of vertical slide guide members 26, and is supported at a varying desired height by a combination of counterweights 40 and a float member 50, seen in FIG. 2

Fixed pulley support posts 52 are seen supported by the channel 14.

A float member 50, seen in FIG. 2, is operatively attached to the vertically movable upper dam plate 124 in FIG 10. The float member 50 automatically retains the paddle wheel 122 at a height wherein the horizontal shaft 128 is slightly above the water level 32 inside the channel 14, thus allowing the water having driven the paddle wheel 122 free discharge into air above sea level 44.

The device 130 seen in FIG. 12 is provided with a vertical-shaft 132 helical water wheel 134. An electric power generator 136 is mounted directly thereover and is connected to be driven by the vertical shaft 132.

The helical blade 138 of the water wheel 134 is provided with buckets 140 to retain the water during its descent from the channel 14 to sea level 44. An aperture 142 is cut in the moving dam plate 144 to allow the water from the level 32 to impact the helical blade 138, whereafter the water is freely discharged into air above sea level 44.

The long channel 14 has been previously described with reference to FIG 1a and 1b.

In the embodiment of the long channel 150 portrayed in FIG. 13 there is seen that the channel has a sloped shore-facing side 152. A large sea wave represented by a line 154 enters the channel 150 through the one-way apertures 34, which extend both below and above sea level 44, allowing waves, both under and above sea level to enter the channel 150. The large wave 154 impacts the side 152 at an angle other than the perpendicular and thereby reduces shock and extends the life of the channel 150. The water contained in the large sea wave 154 remains inside the channel 150 and contributes to raising the water level 32 inside the channel 150.

The scope of the described invention is intended to include all embodiments coming within the meaning of the following claims. The foregoing examples illustrate useful forms of the invention, but are not to be considered as limiting its scope, as those skilled in the art will be aware that additional variants and modifications of the invention can readily be formulated without departing from the meaning of the following claims.