Wind Turbine
A wind turbine having a plurality of airfoils disposed on the end of spokes which extend from a hub connected to a drive shaft. The airfoils are preferably disposed on an angle of about 40 to about 50 degrees with respect to the plane of rotation of the hub.
This application claims priority to and the benefit of the filing of U.S. Provisional Patent Application Ser. No. 61/283,668, entitled “The Tully Wind Turbine Electricity Generator”, filed on Dec. 7, 2009, and the specification and drawings thereof are incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention (Technical Field)
Embodiments of the present invention relate to the generation of electricity with a wind driven turbine.
2. Description of Related Art
Known wind-powered devices, such as wind turbines, typically rely on propeller-like structures that are designed primarily for power generation in limited high-velocity wind environments. Most wind turbines which generate electrical power for sale, have diameters approaching 400 and blades which measure nearly 200 feet in length. Obviously, such massive components require specialized shipping procedures, including but not limited to specially-designed semi-trailers. Further, the assembly and repair of such wind turbines requires large and expensive cranes. Such known systems provide little or no work when exposed to low-velocity winds. Still further, such known devices capture only a small portion of the total wind force to which they are exposed, thus resulting in poor efficiency.
Such large wind turbines are exceedingly intrusive on the visual environment and generate significant noise.
Although other manners of generating electricity are known, such as coal-fired, water cooled power plants, such power plants use about 48% of the available potable water, while human consumption of available potable water accounts for only about 9%. Accordingly, replacement of only about 12% of such water-hungry power plants with renewable energy sources, including wind turbines, would thus enable an increase in the consumption of potable water of more than 50% of its current level.
There is thus a present need for a wind turbine which provides a lower profile and allows a less intrusive element in the visual environment, reduces noise, and which helps increase the availability of water for human consumption which is otherwise wasted by water-cooled power plants.
There is also a present need for a wind-powered system which provides significant work even when exposed to low-velocity winds, and which provides comparatively greater outputs than known systems even when exposed to higher-velocities. There is also a need for a wind turbine which can provide significant electrical power output without the need for specialized shipping procedures, or the use of large and expensive cranes for assembly and repair.
BRIEF SUMMARY OF THE INVENTIONAn embodiment of the present invention preferably relates to a wind turbine which includes a central hub orientated to rotate about an axis which lies at an angle of from about substantially horizontal to an angle of about 45 degrees with respect to a vertical axis; a plurality of spokes comprising a proximal end communicably coupled to and extending in a plane which is substantially perpendicular with respect to the axis; and a plurality of airfoils disposed on terminal end portions of the spokes, the spokes each having a distance which is at least as long as one of the airfoils. In one embodiment, the airfoils are optionally oriented into an incoming wind at an angle of about 30 to about 60; about 40 to about 50; and/or about 45 degrees with respect to the plane of rotation of the hub. The spokes can intersect the airfoils in a location at or near the aerodynamic centroid of the airfoil. Optionally, the hub can be orientated to rotate about an axis which is at least substantially horizontal.
In one embodiment, the wind turbine has at least 5 airfoils, at least 10 airfoils, at least 15 airfoils, and more preferably at least 20 airfoils. The spokes can comprise a distance which is at least twice as long as one of said airfoils. Optionally, the turbine can comprise an outer ring of airfoils and one or more inner rings of airfoils. In on embodiment, one or more rings of airfoils can be counter-rotating with respect to one another.
An embodiment of the present invention also relates to a wind turbine which has a central hub, at least eight spokes with a proximal end communicably coupled to the central hub, at least eight airfoils, disposed on terminal end portions of the spokes, the spokes each having a distance which is at least as long as one of the airfoils. Optionally, the central hub can be orientated to rotate about an axis which is substantially horizontal, substantially vertical, and/or some other angle. Optionally, the airfoils can be orientated at an angle of less than about 22 degrees, and/or less than about 17 degrees with respect to a wind stream.
In one embodiment, one or more photovoltaic cells can be disposed on a surface of one or more of the airfoils. Optionally, at least some of the airfoils can be spaced apart by a distance of less than about a width of the airfoil, thus providing a ground effect lift. The central hub can be orientated to rotate about an axis which lies at an angle of between about substantially horizontal to about substantially vertical.
Objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:
Embodiments of the present invention relate to a wind turbine apparatus which can provide several different levels of energy output and which can encompass a range of axes from horizontal to vertical. Optionally, photovoltaic cells, which for purposes of this application and claims can include a photovoltaic film, can be disposed on or otherwise incorporated into one or more components of the wind turbine, thus enhancing the electrical generation capabilities of the present invention.
Embodiments of the present invention provide significantly lower cost energy generation and a more durable system of operation, all with a design which may be erected on almost any sort of terrain. Embodiments of the present invention can operate in prevailing updraft conditions, prevailing down draft conditions, and/or in prevailing horizontal wind conditions.
Embodiments of the present invention provide significantly lower fabrication costs per kilowatt hour as compared with conventional wind turbines, thus reducing the total cost of power generation per kilowatt hour.
Because of the width and number of blades provided in embodiments of the present invention, the area through which the blades travel is readily apparent, particularly as compared with known wind turbines, accordingly, birds are much less likely to fly through the kill zone of the blades. Thus, embodiments of the present invention reduce likelihood of birds being killed as compared with known wind turbines.
In one embodiment, photovoltaic cells can be disposed on one or more surfaces of the wind turbine of the present invention, thus enhancing the electrical output of the turbine. Although desirable results of these embodiments can be achieved at most latitudes, these embodiments are particularly desirable for latitudes of between about 37 degrees north and south latitude and more preferably between about 25 degrees north and south latitude, or across the central and southern portions of the United States or elsewhere.
Referring now to the figures,
Although various sizes of airfoils 12 can be used and will provide desirable results, in one embodiment, airfoils 12 are preferably about 8 to about 16 feet in length and are about 8 to about 16 feet in width, and are more preferably about 10 to about 14 feet in length and about 10 to about 14 feet in width, and most preferably about 12 feet in length and about 12 feet in width. In one embodiment, multiple sizes of turbine 10 can be created from airfoils 12 which have the same approximate dimensions. For example, a relatively small turbine can be formed by providing about 16 airfoils that are about 12 feet by about 12 feet on spokes which are about 23.5 feet in length, while larger turbines can be provided by disposing about 80 airfoils that are about 12 feet by about 12 feet on spokes that are about 117 feet in length. Accordingly, because airfoils which have the previously-identified dimensions can easily be shipped via common shipping methods (for example on tractor trailers) and because both small and large turbines can be fashioned from the same airfoils, the cost of manufacturing and shipping for various sizes of turbines can be greatly reduced from those of conventional wind turbines. In one embodiment, when turbine 10 is assembled, the center to center distance of airfoils 12, at their innermost edges, preferably measures about 8 to about 20 feet, and more preferably about 10 to about 12 feet, and most preferably about 9 to about 10 feet. In one embodiment wherein the spacing between airfoils 12 is less than the length of each airfoil, the spacing and airfoil size causes additional ground-effect lift between adjacent airfoils, thus enhancing the rotational force experienced by shaft 18, this additional ground-effect lift is similar to that encountered by bi-planes. In one embodiment, wherein airfoils 12 comprise a length of about 12 feet, airfoils 12 preferably comprise a thickness of about 2 feet. Ground effect is equivalent to a reduction in drag. Thus, ground effect has a positive and direct effect on the airspeed of airfoil 12.
In one embodiment, as illustrated in
Airfoils 12 can optionally be constructed of a wide variety of materials including but not limited to steel, cast aluminum components, aluminum sheets shaped and reinforced, resin reinforced with glass and/or carbon fiber, plastics such as poured and/or cut urethane, polyethylene, styrene foam or epoxy materials, and the like. Various shapes of all or of portions of airfoils 12 can also optionally be obtained by cutting through a material which has a low melting point, such as plastics and foams, with hot shaped surfaces or devices. High-strength synthetic sheets can optionally be used to form a skin of airfoil 12 by disposing it over an internal skeleton structure. In this embodiment, the synthetic sheets can be pre-coated with a liquid resin, or can be applied to the skeleton and then sprayed with a resin. Airfoils 12 can also optionally be formed in a mold such that the surface geometry can be precisely controlled and such that the mold can be reused multiple times, thus reducing the cost of airfoils 12.
In one embodiment, one or more generators 20 may be fabricated around driveshaft 18, thus reducing and/or eliminating losses caused by mechanical advantage system 24. In embodiments wherein counter-rotating rings of airfoils 12 are provided, a first ring can be used to drive a rotor of the generator in a first direction, while another ring of airfoils 12 drives the stator in an opposite direction.
Embodiments of the present invention provide several airfoils 12, rather than just the three blades found on conventional wind turbines. The cantilever-induced bending moment at their base (i.e. hub connection location) increase as the difference squares with the length of spokes 14, Because Applicant's invention provides more airfoils at less distance from the hub, the forces experienced by Applicant's spokes near the hub are thus able to be distributed over the several spokes. Accordingly, because each spoke experiences significantly less bending, each of the spokes can thus be made from significantly less material as those of conventional wind turbines. For example, a 200 foot long propeller has 16 times higher stresses at the hub than does each spoke of the present invention when such spoke and airfoil instead has overall length of only 50 feet while to producing an equivalent amount of energy. The significant reductions in weight and material sizes which can thus be obtained in accordance with the teachings of the present invention thus result in massive savings not only in material costs but also in construction, shipping, and installation.
Because the airfoils of embodiments of the present invention preferably provide reactive lift as well as significant Bernoulli lift, airfoils 12 preferably provide enough lift to drive turbine 10 even in relatively low wind velocities of less than about 10 miles per hour, more preferably less than about 7 miles per hour, and most preferably less than or about 5 miles per hour.
As best illustrated in
Referring now to
In an alternative embodiment, as illustrated in
To reduce bending moments and/or forces encountered by spokes 14, struts 42 can optionally be connected to spokes 14 at a single or at a plurality of locations along spokes 14. Optionally, hub 16 can comprise an extension for connection of struts 14, optionally, however, driveshaft 18 can extend through a central opening in hub 16 and struts 42 (
In one embodiment, spokes 14 preferably extend from hub 16 and through side 44 (see
Optionally, support structures can be disposed between one or more of spokes 14 and/or airfoils 12. For example, as best illustrated in
Spokes 14 may be constructed of a wide variety of materials or combinations thereof including but not limited to metals, stainless steel, steel, aluminum, titanium, resins reinforced with glass or carbon fibers; timber or laminated timber reinforced with an outside structural sheath of carbon or glass fiber reinforced resins, and plastics. Optionally, spokes 14 can comprise a cross-sectional shape which includes but is not limited to circular, elliptical, rectangular, polygonal, triangular, H-shaped, I-shaped. Optionally, spokes can have a continuous cross-sectional shape, or one which changes over a distance. Spokes 14 can comprise a shape which tapers from their proximal ends, connected at hub 16, out to their distal ends, connected at airfoils 12.
Although the various components of embodiments of the present invention can optionally be used form horizontal wind turbine 10, most of those same components can also alternatively be used to form vertical axis wind turbine 60 (see
Optionally, spokes 14 of turbine 60 can be supported at least in part by a plurality of supports 62. Supports 62 can be rigid, semi-rigid, and/or flexible. Supports 62 are preferably attached to support hub 64 which is disposed above or below the spoke that it is attached to. In the embodiment wherein hub 64 is disposed above spokes 14, supports 62 can optionally be made from cables, chains, straps, belts, wires, ropes and/or rods, which can optionally be made from a metal, non-metal, and/or a combination thereof. In addition to supports 62, bracing 48 (not shown) can also optionally be provided on turbine 60 as described for turbine 10. Although
Embodiments of the present invention can be constructed at purpose built diameters, as for example, from about two feet to about 200 feet such that it can be used for large scale power generation, domestic use, and/or for the generation of power for special-purpose applications at remote locations. Optionally, support structure 22 can be configured to accommodate various applications. For example, if turbine 10 is intended to provide power to a remote road sign, the support structure of the sign and also form all or a portion of the support structure of the turbine.
In some embodiments, turbines constructed in accordance with the teachings of the present application can optionally be assembled in pieces or cast in part or in whole.
In turbine 60, each airfoil 12 preferably comprises a high-lift configuration. Optionally, airfoil 12 is orientated at an angle of less than about 30 degrees and more preferably less than 22 degrees, and most preferably less than about 17 degrees to an axis of a wind stream, optionally, however, airfoils 12 can be adjusted to provide a best angle for lift for a particular application of turbine 60.
Optionally, airfoils 12 of turbines 10 and/or 60 can additionally comprise surface vortex generators 70, (see
At low wind speeds, and thus low rotational speeds, airfoils 12 of turbines 10 and/or 60 develops using the Bernoulli principle of low pressure on the upper surface of airfoil 12 and higher pressure on the lower surface of airfoil 12 (when the airfoil is orientated in a substantially horizontal plane). These different pressures thus provide lift to airfoil 12 and drive the rotation at wind velocities of greater than about 15 mph. For lower wind velocities, the lower surface of airfoil 12 preferably acts more as a paddle as a result of “reactive lift” to provide rotation, although some Bernoulli lift is also provided.
For turbines 10 and/or 60, one or more braking systems can optionally be provided such that the speed of turbines 10 and/or 60 can be reduced in during high winds.
While embodiments of the present invention can provide desirable results with virtually any airfoil design capable of generating lift, airfoil 12 preferably comprises a shape similar to that of the National Advisory Committee for Aviation (NACA) airfoil design number 2312. More preferably, however, as illustrated in
In one embodiment, airfoils 12 of turbine 10 are preferably disposed such that they are orientated into the incoming wind on an angle of about 30 to about 60 degrees, more preferably about 40 to about 50 degrees, and most preferably about 45 degrees with respect to the plane of rotation of the hub.
In one embodiment, horizontal turbine 10 or vertical turbine 60 preferably have at least four airfoils 12, more preferably at least 10 airfoils 12, and most preferably at least 16 airfoils 12. In one embodiment, horizontal turbine 10 or vertical turbine 60 have at least 40 airfoils 12. In one embodiment, horizontal turbine 10 and vertical turbine 60 do not comprise four or fewer airfoils 12.
Although in a preferred embodiment airfoils 12 preferably comprise a substantially square shape in plan, embodiments of the present invention can provide desirable results with other plan shapes of airfoils 12, including rectangular. For example, in one embodiment, airfoils 12 can comprise a substantially rectangular non-square shape. In one embodiment, the length of airfoils 12 is not greater than 20 feet. In one embodiment, the length of airfoils 12 is not greater than 12 feet. In one embodiment, airfoils 12 have a length which is not more than twice their width. In one embodiment, aside from the down-turned trailing edge, the high pressure side of airfoil 12 does not comprise a concave shape. In one embodiment, aside from the down-turned trailing edge, the high pressure side of airfoil 12 is substantially planar. Although embodiments of the present invention most preferably comprise turbine 10, which is substantially horizontal and/or turbine 60, which is substantially vertical, the teachings from one or both of those embodiments can optionally be used to form a turbine which resides at some other orientation or which can adjust to operate at two or more orientations. Although embodiments of the present invention preferably comprise spokes 14 which extend into and thus terminate within airfoils 12, for purposes of describing the length of such spokes throughout this application, including the claims, it is understood that such length descriptions are directed to the length of the spoke which lies between the hub and the airfoil and thus does not include those lengths which reside within the airfoil or the hub.
Embodiments of the present invention are readily adaptable to a wide variety of environments, including a wide variety of wind speeds, architectural and other environmental circumstances. The unique characteristics of these embodiments enable them to be adjusted dynamically to be efficient in a wide variety of wind speeds. The unique characteristics enable embodiments to be constructed with relatively light and inexpensive supporting structures. They can also be built in ways that minimize gyroscopic effects that affect alternative approaches to building efficient wind turbine electric generators.
INDUSTRIAL APPLICABILITYThe invention is further illustrated by the following non-limiting example.
Example 1An embodiment of the present invention was modeled in computer modeling software. Simulations and calculations were performed on the modeled embodiment and results were obtained. An airfoil having a width of 12 feet and a length of 12 feet, including a down-turned trailing edge which extended one foot below the airfoil, was modeled.
Based on the modeled airfoil subjected to wind at a relative angle of 45 degrees, it was calculated that the power output from the modeled airfoil at one revolution per minute (RPM) is about 482.3 Watts. Increasing the rotation rate to five RPM increases the output of the modeled airfoil to about 723.45 Watts. Accordingly, for embodiments of the present invention which comprise 20 airfoils results in a total wattage output of about 9,646 watts at one RPM, and about 14,469 watts at five RPM. A turbine constructed according to the teachings of the present invention is thus capable of generating 32.8 mega watt hours of power at one RPM and 48.6 mega watt hours at five RPM.
The preceding examples can be repeated with similar success by substituting the generically or specifically described components and/or operating conditions of this invention for those used in the preceding examples.
Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.
Claims
1: A wind turbine comprising:
- a central hub, said central hub oriented to rotate about an axis of rotation which resides at an angle of from about substantially horizontal to an angle of about 45 degrees with respect to a vertical axis;
- a plurality of spokes, said spokes each comprising a proximal end communicably coupled to and extending in a plane of rotation which is substantially perpendicular with respect to the axis of rotation and said spokes each comprising a terminal end;
- a plurality of airfoils disposed on said terminal end portions of said spokes; and
- said spokes each having a length which is at least as long as one of said airfoils.
2: The wind turbine of claim 1 wherein said airfoils are oriented into an incoming wind at an angle of about 30 to about 60 degrees with respect to the plane of rotation of said hub.
3: The wind turbine of claim 2 wherein said plurality of airfoils are oriented into an incoming wind at an angle of about 40 to about 50 degrees with respect to the plane of rotation of said hub.
4: The wind turbine of claim 3 wherein said plurality of airfoils are oriented into an incoming wind at an angle of about 45 degrees with respect to the plane of rotation of said hub.
5: The wind turbine of claim 1 wherein said spokes intersect said airfoils in a location at or near an aerodynamic centroid of said airfoils.
6: The wind turbine of claim 1 wherein said plurality of airfoils comprise at least five airfoils.
7: The wind turbine of claim 6 wherein said plurality of airfoils comprise at least 10 airfoils.
8: The wind turbine of claim 7 wherein said plurality of airfoils comprise at least 15 airfoils.
9: The wind turbine of claim 8 wherein said plurality of airfoils comprise at least 20 airfoils.
10: The wind turbine of claim 1 wherein said length of said spokes is at least twice as long as one of said airfoils.
11: The wind turbine of claim 1 wherein said plurality of airfoils comprise an outer ring of airfoils and an inner ring of airfoils.
12: The wind turbine of claim 11 wherein said outer and inner rings of airfoils counter-rotate with respect to one another.
13: (canceled)
14: A wind turbine comprising:
- a central hub:
- at least eight spokes, each said spoke comprising a proximal end communicably coupled to said central hub and a terminal end portion;
- at least eight airfoils, said airfoils disposed on said terminal and portions of said spokes, said spokes each comprising a length which is at least as long as one of said airfoils.
15: The wind turbine of claim 14 wherein said central hub is oriented to rotate about an axis which is substantially horizontal.
16: The wind turbine of claim 14 wherein said central hub is oriented to rotate about an axis which is substantially vertical.
17: The wind turbine of claim 14 wherein said airfoils are oriented into an incoming wind at an angle of about 40 to about 50 degrees with respect to the plane of rotation of the hub.
18: (canceled)
19: The wind turbine of claim 14 wherein said airfoils are oriented at an angle of less than about 17 degrees with respect to a wind stream.
20: The wind turbine of claim 14 wherein one or more photovoltaic cells are disposed on a surface of one or more of said airfoils.
21: The wind turbine of claim 14 wherein at least some of said airfoils are spaced apart by a distance of less than about a width of said airfoils, thus providing a ground effect lift.
22: The wind turbine of claim 14 wherein said central hub is oriented to rotate about an axis which lies at an angle of between about substantially horizontal to about substantially vertical.
Type: Application
Filed: Dec 7, 2010
Publication Date: May 31, 2012
Inventor: Daniel F. Tully (Santa Fe, NM)
Application Number: 12/962,415
International Classification: F04D 29/18 (20060101);