Patent Application
20150204299
1. Field of the Invention
This invention relates to the generation of power from water flowing in rivers, streams, brooks, and other renewable sources of water. More particularly, the invention relates to the generation of electricity from such sources.
2. Background of the Invention
Power has been generated from rivers and other natural sources of flowing water for many generations. For example, water wheels have been used for powering machinery during the industrial revolution. However, such power generation has normally relied on the movement of the water, i.e. the momentum of the water as it flows generally horizontally along a water course such as a river bed. More recently, electricity has been generated by building dams across rivers to form reservoirs and feeding the water from the reservoirs through passages to turbines, but again use is made of the momentum of water moving through the passages generally at high speed and under high pressure. Dams and the associated equipment are extremely expensive to build and the creation of reservoirs has involved the flooding of otherwise useful land and damage to flora and fauna.
Recently, as the price of fossil fuels has increased and locations for new dams and reservoirs has declined, there is a need to generate power in new ways, particularly ways that are environmentally benign and that employ sources of power that are continuously renewable. Power generated from wind energy has become popular, but winds do not blow constantly, so the equipment often stands idle for long periods of time or can be damaged during storms. Furthermore, wind turbines are frequently unpopular because they can be visually unappealing and noisy. The generation of electricity from solar energy has also become popular, but can only be carried out during the day, or when clouds are absent, so again there are long periods when the equipment is idle.
It would therefore be desirable to provide means to generate power, particularly electrical energy, from more reliable and readily available sources, such as rivers, while avoiding the disadvantages of prior known approaches.
The present invention makes use of the weight of water and/or buoyancy (weight of water displaced) to generate energy, particularly in the form of electricity.
One exemplary embodiment of the present invention provides an apparatus for generating power from a source of water. The apparatus includes an upstanding structure adapted for support on ground adjacent to a renewable supply of water having an elevated region relative to the ground, the structure having a water inlet at a height no higher than the elevated region of the supply of water and a water outlet at a lower position than the inlet; a conduit for water extending between the elevated region of the water supply and the water inlet; and a gravity-operated energy converter supported by the structure that causes water to descend vertically between the horizontal levels of the inlet and the outlet while utilizing weight of the water thus descending to drive at least one movable element and thereby produce power.
The upstanding structure may be any kind of support for the operational elements of the energy converter. For example, in one embodiment, it may be a vertical post or wall embedded in the ground at its lower end, or in another embodiment, it may be a housing, such as a building, silo, hangar or the like intended both to shelter the operational elements and to provide support for them. In those cases where the structure is a building, it may be a prefabricated structure having its own foundations or designed for foundations provided at the site, or it may be a custom-built structure made of brick, concrete, wood, metal or other construction materials assembled at the site. Whatever the structure, adequate support for it should be provided by the ground so that the operational elements are securely held.
The conduit used to convey water to the structure may be of any suitable kind, e.g. a pipe, open-topped channel, flexible hose or duct, rigid aqueduct, or the like, and it may be made of any suitable material, e.g. plastics, brick, concrete, wood, metal, etc.
The gravity-operated energy converter is any machine, engine or motor that is capable of converting potential energy of water into kinetic energy, e.g. the movement of a movable element(s), e.g. the descent of water containers, the rotation of a shaft, the rotation of a rotor of a hydraulic motor, or the like. The kinetic energy can then be used for the generation of electricity by operation of a suitable electrical generator. Preferably, the movements of the movable element are passed through a gearbox or the like before connection to a generator in order to change the ratio of speeds of movement. Generally, the gearbox is used to increase the rate of movement to suit the input requirements of the generator. The gearbox and the generator may act as a brake or governor on the speed of movement of the movable element(s), which may be desirable to allow adequate use of available water supplies.
In a particular embodiment, the energy converter includes an upper generally horizontal rotatable shaft, a lower generally horizontal rotatable shaft positioned at a distance vertically below the upper shaft, at least one endless flexible band (and preferably two) passing around the shafts and a plurality of water containers supported at intervals along the bands, each container having an open end orientated to receive water from the conduit at the water inlet, with the containers acting as the at least one movable element. The flexible band may be in the form of an endless flexible chain engaging a sprocket wheel fixed on each of the upper and lower rotatable shafts.
The water containers may be elongated boxes that are held generally horizontal by the flexible band or bands, the open ends of the containers being at the tops of the boxes on one side of a vertical loop formed by the band or bands, and at the bottom of the boxes on an opposite side of the loop.
One of the upper rotatable shaft and the lower rotatable shaft may be driven by the flexible band or bands and may be used to transfer movement of the at least one movable element.
In another exemplary embodiment, the energy converter may include a water tank fed with water at a top thereof via the water inlet and feeding water at a bottom thereof to the water outlet, the energy converter including a hydraulic motor at or near the bottom of the tank and the at least one movable element comprises a rotor within the hydraulic motor driven by water passing between the tank to the water outlet.
In the exemplary embodiments, the renewable supply of water may be any natural or artificial supply of water, e.g. a river, stream or brook.
According to another exemplary embodiment, the invention provides a method of generating power from a renewable supply of water having ground adjacent thereto and a region of the water supply elevated relative to the adjacent ground. The method comprises: channeling water from the elevated region of the water supply to a position above the adjacent ground; causing the water to descend generally vertically (and ideally precisely vertically) from the position above the ground to a lower position adjacent to the ground; and utilizing weight of the water to drive at least one movable element as the water descends, and thereby converting gravity-based power of the water to movement of the at least one movable element.
Yet another exemplary embodiment relates to the gravity-operated energy converter of the above apparatus.
In particular embodiments, use is made of buoyancy, an upward force, to complement the use of weight, a downward force, in moving the movable element for the generation of energy. In one form, open-topped containers for holding water are, after their descent under gravity, emptied, inverted and introduced at the bottom of a column of water so that they generate a buoyancy force based on displaced water as they are caused to ascend. Both the weight and the buoyancy forces are harnessed to generate energy. More particularly, this may be achieved in a form of the invention in which containers are rotated about a vertical loop-like path with the containers being filled with water on the descending side of the loop and empty containers rise on the ascending side of the loop. Two adjacent vertical passageways may be provided, one for the descending containers and the other for the ascending containers. The ascending shaft is filled with water from the renewable source. A pair of dams operating in concert form a water-lock system at the lower end of the ascending passageway to retain water within the passageway while allowing empty and inverted containers to enter at the bottom of the ascending passageway. The top of the ascending passageway may be open to allow the empty containers to invert themselves again and return to the descending passageway.
The exemplary embodiments of the present invention may have the advantage that many readily available renewable sources of water may be utilized for energy generation without substantial capital outlay and destruction of the environment. Sources of water having relatively small volumes of flow may be utilized and the generated power may be fairly unaffected by differences of such volumes over time. Moreover, power may be generated constantly over a full 24 hour period without change. Nevertheless, if available volumes of flow fall below suitable limits for adequate power production over short periods of time, other sources of water (e.g. city water) may be used to fill the gap on a temporary basis.
The exemplary embodiments have the advantage that the apparatus may have a very small horizontal “footprint”, i.e. compared for example to a water wheel where the water is caused to move both horizontally as well as vertically (i.e. in an arc) as it descends, the apparatus may occupy a very limited horizontal area since the water descends vertically. To limit the horizontal footprint of the apparatus even further, an “elevator car” type of apparatus may be employed in which a container is filled with water at the top of a shaft or other support structure, allowed to descend suspended by cables, chains or bands connected to a generator of electricity, emptied at the bottom of the shaft, and then lifted by an electric motor once more via the same cables, chains or bands to the top of the shaft. The energy generated by the descent of the full container will clearly be much more than the energy required to raise the empty container. Since the empty container is raised vertically along the same trajectory as the descending full container, the footprint of such apparatus may be little more than the horizontal extend of the container itself. This exemplary embodiment is also of value when the rate of flow of water to the generating apparatus is slow or of low volume since the empty container at the top of the shaft may be kept in place long enough to fill completely, then the water supply may be held back by a simple movable dam or other water gate as the container descends, empties and then ascends back to the starting position.
A first exemplary embodiment of the invention is shown in
An apparatus for generating power is provided close to the river. The apparatus includes an upstanding structure 20 supported on the ground adjacent to the river at the lower region 13 of the ground. In this exemplary embodiment, the structure is in the form of an enclosed silo-like building made of strong construction material, such as concrete or metal, but it could alternatively be a structure as simple as a upstanding post set firmly within the ground. The structure 20 has a top 21 at a level similar to or greater than the level of the elevated region 15 of the river. A conduit 22 for water extends from the elevated region 15 of the river to the structure 20 for delivery of water from the river to the structure. The conduit 22, which may be in the form of a closed pipeline or an open-topped channel, is generally horizontal or preferably slightly downwardly inclined towards the structure 20 to ensure an adequate and preferably continuous supply of water through the conduit. The entrance of the conduit 22 at the river end may be supported on the river bed itself and, if desired, may be provided with a filter to prevent entry of debris or other objects. At the opposite end, the conduit 22 enters the structure through a water inlet 23 and eventually leaves through a water outlet 24. However, if the upstanding structure is not an enclosing housing, e.g. it is a simple post, the water inlet would merely be a region where the water is delivered from the end of the conduit 22 and the water outlet would be a region where water is delivered to the lower region 13 of the ground to return eventually to the river 10. The water from the conduit 22 is supplied to a gravity-operated energy converter 25 shown in greater detail in
Therefore, as shown in
The lower rotatable shaft 27 is mechanically connected to a gearbox 35, and an output shaft of the gearbox is connected to a generator of electricity 36 as shown schematically in
It will be seen that, in this exemplary embodiment, use is made only of the weight of the water in the containers 30 which descend vertically under the effects of gravity between the horizontal levels of the inlet 24 and the outlet 24. The containers 30 form movable elements that convert the potential energy of the water into kinetic energy to rotate the shafts 26 and 27 and thereby operate the generator 36 to produce electricity. There is no attempt to provide or make use of sideways momentum of the water, thus avoiding sloping runs or arced paths of descent, and the vertical descent of the water under gravity is alone used to generate the energy. Consequently, the output of the energy converter 25 remains much the same regardless of the rate of flow of water in the river 10 and the conduit 22, so there is little change of energy output between wet and dry seasons provided the quantity of water in the river remains above a certain minimum, i.e. sufficient for delivery along the conduit 22 for filling of the containers 30.
The vertical separation of the shafts 26 and 27, and thus the height of the energy converter 25 and the supporting structure 20, may vary to suit particular environments, and the vertical separation generally dictated by the fall in vertical level of the river. Clearly, the water inlet 23 should be no higher than the surface of the river water in the elevated region 15, or water will not flow under gravity to the structure 20. However, the inlet 23 should be as high as possible (consistent with reliable water flow through the conduit 22) so that a maximum distance of fall is available for the containers 30. The sizes of the containers 30 may also be determined by particular environments, e.g. they should take into account the flow of water at the inlet 23, and should be large enough to be filled substantially completely while avoiding undue spillage caused by overfilling, thereby ideally using 100% of the water diverted from the river for energy generation. As a particular example, the containers 30 may be generally rectangular as shown in
To obtain a suitable difference in vertical height, it may be necessary, e.g. in gently descending terrain, to make the conduit 22 quite long, in which case suitable intermediate supports (not shown) would be provided. However, since the water descends under gravity and the conduit may be made of inexpensive materials, such increased lengths will not add significantly to the capital or operational costs of the apparatus. It is therefore not necessary to provide the structure 20 directly adjacent to rapids or a water fall or the like, although this may be preferred.
A modification of the embodiment above is shown in
The conduit 22 in this exemplary embodiment extends fully across the top of the structure 20 and is provided with two outlets for water, i.e. a first water outlet 60 positioned directly above the first of the containers in the first vertical passageway 51 on the fill-side of the loops 29, and a second outlet 61 positioned above the second vertical passageway 52. The first water outlet 61 operates to provide water to fill containers 30a in the first vertical passageway 51 in the same manner as in the embodiment of
The movements of the movable dams 55 and 56 are facilitated by providing them with elongated slots 57 that are closable by rotatable elongated blades 58 held within the slots and provided with rotatable bearings (not shown) at their respective longitudinal ends. The blades 58 act as valves that either prevent passage of water through the slots 57, when rotated to extend fully across the slots 57 to block the slots, or to allow passage of water through the slots when rotated to unblock the slots 57. In the operations previously described, the blades 58 in the second movable dam 56 are rotated to the blocking position before the second movable dam is pivoted from the horizontal position to the upright position to prevent loss of water from the space 65 when it is filled, but the blades 58 are rotated to the unblocked position just before the second movable dam 56 is rotated from the upright position to the generally horizontal position thereby allowing drainage of water from the space 65 through the slots 57 in the second movable dam. This prevents a cascade of water flowing over the top of the second movable dam 56, and reduces the pressure on the dam that would otherwise resists its pivotal motion to its generally horizontal position. Similarly, the blades 58 in the first movable dam 55 are rotated to the unblocked position as the second movable dam is pivoted from its generally upright position to its horizontal position extending across the second vertical passageway 52. This allows the second dam to flow easily through the water in the second vertical passageway 52 from one position to the other because water can flow easily through slots 57 in the dam. When the second movable dam 56 is in its horizontal position, the blades 58 are then moved to the blocking position closing the slots 57 so that, when water is released from the space 65 beneath the first movable dam 55, the first movable dam supports the column of water above it without drainage of water into the space 65. Once an empty container 30b is positioned within the space 65, and the second movable dam is moved to the vertical position, the blades 58 in the first movable dam 55 are then rotated to the unblocked position so that water flows through the slots 57 in the first movable dam to fill the space 65. The first movable dam 55 can then be rotated through the water to its upright position to allow upward passage of the container 30b. The rotation of the blades 58 may be driven by electric, pneumatic or hydraulic motors (not shown) connected to the ends of the blades. The pivoting of the first and second movable dams 55 and 56 may also be effected by additional electric, pneumatic or hydraulic motors (not shown) connected to the first and second movable dams. The sequence of operations of the rotations of the blades and the pivoting of the dams may be under computer numeric control, e.g. by means of a programmable logic controller (not shown), to automate and coordinate the required operations.
Although the first and second movable dams 55 and 56 have been shown in this exemplary embodiment as located entirely within the structure 20 and as pivoting from a side wall or bottom wall of structure 20, the dams may instead be arranged to pass through slots of corresponding size in the respective side wall or bottom wall of the structure and caused to move either horizontally (in the case of the first movable dam 55) or vertically (in the case of the second movable dam 56) into and out of the second vertical passageway 52 to thereby enter and block the passageway, or alternatively to move through the slot and out of the passageway to allow suitable clearance for movement of a container 30a or 30b. Such an arrangement reduces the extent of movement required of a container around the loops 29 to clear the respective dams before the dams can again be moved. This makes it possible to provide the loops 29 with more containers 30 since the containers do not have to be so widely separated. It may also make it possible in this case to reduce the volume of the space 65 beneath the first movable dam 55, and thereby reduce the loss of water from the second vertical passageway 52 during each cycle of operation of the dams.
Whichever way of operating the dams is employed, it may be advantageous to cause the loops 29 to operate in a stop-go fashion rather than allow a smooth and continuous rotation of the loops and containers. This is because the rotation of the loops 29 may be stopped to allow proper movement of the first and second movable dams 55 and 56 before a newly emptied container 30b enters the space 65, and also again before the space 65 is filled with water and the first movable dam 55 is moved out of the way of ascent of the container 30b through the second vertical passageway 52. Time may also be taken to refill the second vertical passageway 52 to the maximum level following the introduction of water into the space 65. To provide for such stop-go motion of the loops and containers, brakes (not shown) selectively preventing or permitting rotation of the upper rotatable shaft 26 or the lower rotatable shaft 27, or both, may be provided. Such brakes may also be under computer numerical control to operate automatically and in concert with the opening and closing of the first and second movable dams 55 and 56, and the blades 58 within the slots 57 of those dams.
The advantage of the embodiments shown in
A further exemplary embodiment of the invention is shown in
In this embodiment, the upstanding structure 20 may be a custom built building designed for support and stabilization of the water tank 40 bearing in mind the considerable weight of such a tank when filled with water.
In yet another exemplary embodiment, as shown in
While particular embodiments of the invention have been illustrated and described, it would be clear to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2013/050119 | 2/15/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61599978 | Feb 2012 | US | |
| 61724335 | Nov 2012 | US |
