EP1778972A1

EP1778972A1 - Wind energy extraction system

Info

Publication number: EP1778972A1
Application number: EP05767404A
Authority: EP
Inventors: Angus J. Tocher
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-07-16
Filing date: 2005-07-15
Publication date: 2007-05-02
Also published as: JP4954066B2; AU2005263138A2; WO2006007696A1; AU2005263138A1; AU2005263138B2; JP2008506877A; EP1778972A4; AU2005263138C1

Abstract

A habitat friendly, pressure conversion, wind energy extraction system is disclosed for safely extracting usable energy from wind. The invention includes one or more shrouds or concentrator wings that convert the dynamic pressure of wind into relatively lower static pressure and thereby induces a vacuum that draws wind into a turbine centralized within the shrouds or concentrator wings. As such, the turbine impellor blades may be significantly smaller than the large diameter rotor blades of current popular designs and may be enclosed within the shrouds or concentrator wings that present themselves as highly visible objects and as such are easily avoided by birds in flight. The invention in particular includes a device and method of airflow regulation than minimizes or prevents the stalling, or the generation of a turbulent flow of wind over or between the shrouds or concentrator wings of the invention. This stalling has been shown to occur when airflow is quickly accelerated by force of vacuum and drawn out of the turbine shroud which then mixes with and disturbs the otherwise smooth flow of wind over or between the shrouds or concentrator wings. The system may also include an aerobrake that responds quickly to protect the impellor blades or associated mechanisms from overspeeding or exceeding other design limitations under gusting or violent wind conditions. The invention may also include several other novel features such as power converters for extending the impellor or impellors into the free flowing accelerated wind, an aerobrake to protect the impellor from overspeeding, and two novel forms of intowind guidance systems. Other advantages and objects are as well disclosed that increase safety and wind energy extraction efficiency and allow the invention to be effectively installed within urban settings.

Description

WIND ENERGY EXTRACTION SYSTEM

BACKGROUND OF THE INVENTION

The present invention relates to using wind energy and in particular, to safely and efficiently extracting energy from the wind and converting it to usable energy.

Popular wind turbines having long rotor blades cause problems such as visual and noise pollution and, perhaps of most immediate public concern, bird strikes. As a result, shrouded turbines have developed. Shrouded turbines generally allow the use of smaller and more enclosed rotor blades or impellors, and have physical shrouds or ring shaped concentrator wings that are highly visible to birds in flight but at the same time do not present moving objects, such as large rotating blades that are considered by many to visually mar the natural landscape. Of the shrouded wind turbines, versions having two or more concentrator wings that allow the wind to flow between the concentrator wings and develop a vacuum or suction that drives the turbine, have demonstrated, in recent times, to be the most promising and efficient devices. See for example, Journal of Renewable Energy (February, 2003) by Dr. H. Grassmann et al., is entitled "A Partially Static Turbine - first experimental results". Other references describing wind energy conversion devices with shrouds include United States patent nos. 5,599,172; 4,075,500; 4,140,433; 4,204,799; and 5,464,320 and European Patent Application No. EP1359320A1.

This invention provides an improvement in wind energy extraction devices.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a system and method for safely and efficiently extracting energy from wind and converting it to usable energy comprising one or more concentrator wings that react with a flow of wind to induce a drop in static air pressure that is then used to drive one or more impellors and one or more power converters; and a flow regulator having aerodynamic surfaces directing a flow of wind impinging upon said flow regulator outwards from said flow regulator and towards a said flow of wind reacting with said one or more concentrator wings.

According to a further aspect of the invention, there is provided a wind energy extraction device, comprising an impellor and associated power converter for the impellor; concentrator wings disposed about the impellor, the concentrator wings being spaced apart to permit air flow between the concentrator wings; the impellor being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings; and a flow regulator positioned downstream of the impellor, the flow regulator having wind deflecting aerodynamic surfaces that are contoured to enhance laminar flow of the air flow between the concentrator wings.

According to a further aspect of the invention, there is provided a wind energy extraction device, comprising plural impellors and at least one associated power converter for the impellors, concentrator wings disposed about the impellors, the concentrator wings being spaced apart to permit air flow between the concentrator wings; and the plural impellors being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings.

According to further aspects of the invention, there may be provided additionally one or more of the following: an aerobrake such that the proximity of said turbine shroud to said flow regulator is adjusted to control the flow of wind through said turbine shroud; wherein more than one said power converters are positioned on the leeward side of said aerodynamic surfaces of said flow regulator; and further comprising more than one impellor driveshafts connecting more than one said impellors to more than one said power converters, said more than one impellor driveshafts extending out of said flow regulator and positioning more than one said impellors within the flow of wind passing through said turbine shroud, such that more than one said power converters operate in concert to control the rotational speed of more than one said power converters; a downwind guidance for supporting a plurality of elements to include at least said one or more concentrator wings and said flow regulator, said downwind guidance presenting little obstruction to the higher speed wind flow upstream of said elements, said downwind guidance facilitating the orientation of said plurality of elements approximately into the oncoming wind and said downwind guidance comprising a lee support that supports said plurality of elements and extends in a downwind direction then turns outward and connects with a swivel that allows said plurality of elements to rotate around a common axis and effect said orientation; an alternate downwind guidance for supporting a plurality of elements to include at least said one or more concentrator wings and said flow regulator, and for facilitating the orientation of said plurality of elements appropriately into the oncoming wind; and further comprising a riser to extend the said plurality of elements into said oncoming wind, at least a part of said riser extending on the leeward side of said aerodynamic surfaces of said flow regulator; and further comprising at least one swivel to allow said plurality of elements to rotate about said swivel and effect said orientation.

Further objects and advantages of the present invention will become apparent from consideration of the following description and accompanying drawings.

Accordingly, it is the object of the present invention to provide a wind energy extraction device and method that includes one or more of the following objects and advantages:

1. To provide a flow regulation device or method to increase the wind energy extraction efficiency of a wind turbine having one or more shrouds or concentrator wings especially in conditions of higher wind speeds.

2. To provide a simple, cost effective and fast-responding aerobraking device or method to protect the wind turbine's impellor or associated components from overspeeding or exceeding other design limitations during gusty or high wind conditions. 3. To provide an impellor driveshaft that extends from the flow regulator in order to house the power converter within the flow regulator or shield the power converter on the downwind side of the aerodynamic surfaces of the flow regulator so as to reduce or eliminate the obstruction of an open or faired power converter that occurs when it is positioned within a high speed wind flow within a turbine shroud or concentrator wing. 4. To provide a simple and cost effective downwind guidance device or method to permit the present invention to orient appropriately into the oncoming wind such that the guidance system is presented downstream of the concentrator wings and impellor to increase wind energy extraction efficiency. 5. To provide a system that is safe to humans and wildlife and particular to birds in flight.

6. To provide a system that generates a low degree of vibration and noise to be more suitable for installation within both rural and urban environments and attached to man-made buildings and structures. 7. To provide a system that is able to extract energy from higher speed winds than shroud-less wind turbines of popular designs.

8. To provide a wind energy extraction system that has overall reduced design, production and maintenance costs and expenses.

9. To provide a wind energy extraction system to serve a dual purpose within urban settings as both a roadside lamp standard and wind/electric generator.

10. To provide a wind energy extraction system that may use multiple impellors and multiple power converters so that the task of preventing overspeeding of the impellors or power converters in higher wind conditions may be shared by the magnetic, electrical or mechanical resistance of the multiple power converters.

11. To provide a wind energy extraction system that includes a stationary riser element that supports other elements of the system that are permitted to rotate about the riser element and align appropriately into the oncoming wind, and as well supports a lamp on top of the riser element for illuminating roadways, or an electrical insulator for carrying a power transmission line.

BRIEF DESCRIPTION OF THE DRAWINGS

There will now be described preferred embodiments of the invention by reference to the drawings by way of example, in which like numerals denote like elements, and in which:

Fig. 1 provides, on the left side of the page, a perspective view of the invention, and on the right side of the page, a cross-sectional view of the same revealing additional internal components.

Fig. 2 is a cross-sectional view of the invention indicating a non-aerobraked position of the concentrator wings, turbine shroud and associated components.

Fig. 3 is a cross-sectional view of the invention indicating an aero-braked position of the concentrator wings, turbine shroud and associated components.

Fig. 4 is a schematic cross-sectional view of the windflow, indicated by arrows, interacting with the invention in a non-aerobraked condition. Fig. 5 is a schematic cross-sectional view of same, with the invention in an aerobraked condition.

Fig. 6 is a schematic cross-sectional view of same, but without the aerobrake indicated so as to illustrate turbulence generated by the unregulated flow of wind out of the turbine shroud. Fig. 7 is a duplication of Fig. 1 but including riser and foundation components and indicating the swivel action of the downwind guidance system.

Fig. 8 provides a plan view of a further embodiment of the invention revealing the introduction of multiple impellors and power converters, and indicating concentrator wings having straight running sections rather than the curving sections of previous figures. Fig. 9 is a cross-sectional view of a further embodiment of the invention indicating a tower or riser running downwind of the aerodynamic surfaces of the flow regulator and having concentrator wings that serve as the turbine shroud enclosing the impellors as illustrated. Fig. 10 provides two perspective views of the further embodiment of the invention, as also illustrated by Fig's 8 and 9, and presents elements of the invention rotated 90 degrees with respect to each other around a swivel or swivels according to the action provided by a system of alternate downwind guidance.

Fig. 11 provides an additional perspective view of two of the wind energy extraction systems each having in this case two sets of concentrator wings and three impellors. Also indicated are insulators mounted on top of the riser elements and carrying a transmission line interconnecting the two wind energy extraction systems and a utility power pole also indicated.

DETAILED DESCRIPTION

In this patent document, the word "comprising" is used in its inclusive sense and does not exclude other elements being present. The indefinite article "a" before an element does not exclude others of the same element being present.

The description of the wind energy extraction device 10 as presented in Fig. 1 must begin with a description of how shrouded wind turbines having one or more concentrator wings 12 operate. Fig. 6 therefore illustrates schematically, a cross section of the flow of wind through turbine shroud 14 and through three additional shrouds or concentrator wings 12. Turbine shroud 14 serves to enclose impellor 16 which in turn serves to react with the wind flowing through turbine shroud 14 and drive power converter 22, not shown in this illustration, such as an alternator or generator. Concentrator wings 12 operate fundamentally the same as aircraft wings and have similar profiles as may be readily seen from Fig. 6. These profiles generally have a top convex shaped surface to accelerate the flow of wind, and a lower flattened or concaved surface that tends to slightly decelerate the flow of wind past these surfaces. The profiles of concentrator wings 12 as illustrated are inclined, or have, in aeronautical terms, an angle of incidence that cause the wind flow to be deflected outwards from a central axis that runs parallel with the wind flow and concentric with concentrator wings 12 and turbine shroud 14. The obvious difference between concentrator wings 12 and wings of an aircraft is that concentrator wings 12 are generally, but not necessarily, ring shaped. Those skilled in the art of aeronautics will readily appreciate the interactions that occur when two or more aircraft wings are staged one above the other as in, for example, the Stearman biplane that continues to serve as a high load lifting agricultural spray aircraft, and the highly maneuverable Sopwith triplane of World War I service. Essentially, the lower wing, in the biplane or triplane example, comparable to the largest diameter concentrator wing 12 in the example of wind energy extraction device 10, induces a lower static pressure region over the top surface of the wing that in turn causes an acceleration of the wind flow past the lower surface of the above wing, comparable to the second largest diameter concentrator wing 12 in the example of wind energy extraction device 10. This in turn causes an increased acceleration of the flow of wind over the top surface of this wing. This configuration of multiple aircraft wings is used generally where higher lift and lower stall speeds are desired when it is necessary to limit the overall span of the wings to increase maneuverability of the aircraft. In the present wind energy extraction device, this effect is used to increase the static pressure differential occurring between the inlet of wind to turbine shroud 14 and the outlet. Another way of understanding the interaction of concentrator wings 12 in wind energy extraction device 10 is to appreciate that the largest concentrator wing 12 will induce a lower static air pressure field above its top surface and this field of lower static pressure will be further concentrated by the next largest concentrator wing 12 and so on until at the area where the airflow exits turbine shroud 14, this field is most highly concentrated. It is the static pressure gradient therefore between the inlet of turbine shroud 14 and the outlet of same that causes the wind to be drawn powerfully through turbine shroud 14 and drive impellor 16 and power converter 22. This draw can in fact be so powerful, especially in higher winds, that the flow of wind outwards from turbine shroud 14 can disturb the smooth or laminar flow of wind over and between concentrator wings 12. This occurrence is illustrated in Fig. 6 by the wavy appearance of the arrows indicating a disturbed wind flow over and between concentrator wings 12. This phenomenon has been verified both experimentally and through computer simulation using modern fluid flow computer software. As the wind flow increases in velocity, the stream or jet of wind exiting turbine shroud 14 multiplies in velocity and a point is reached where the smooth flow of wind over and between concentrator wings 12 suddenly becomes turbulent. When this occurs, the low pressure fields generated by concentrator wings 12 break down and little additional power becomes available. In aeronautical terms this is called wing stalling. This occurs when the smooth flow of wind over the top surface of a wing suddenly separates further upwind and becomes turbulent. This may occur where the wing is subjected to too great an 'angle of attack' to the oncoming wind under low airspeeds or when the wing loading is increased such as during a steep banking turn. At such point, a dramatic loss of lift occurs from which the pilot must recover. An objective of the wind energy extraction device described here is to provide a solution to this shortcoming of the prior art that is not dependant on any improved impellor design and is able to accommodate higher wind speeds without the stalling of concentrator wings 12 as continues to occur in the prior art.

Fig. 4 schematically illustrates a cross section of the more laminar flow of wind over and between concentrator wings 12 when the device of the present wind energy extraction device includes flow regulator 18. Flow regulator 18 is a component having aerodynamic surfaces 50 that cause the stream of wind that is drawn into turbine shroud 14 to be directed outwards and away from a central axis running approximately parallel with the oncoming wind and through the centers, in one embodiment, of concentrator wings 12. This re-direction of the jet of wind exiting turbine shroud 14 maintains or promotes a smooth flow of wind over the top surfaces of concentrator wings 12 and thereby eliminates or reduces the aerodynamic stalling of concentrator wings 12 that would otherwise occur. As first glance, the introduction of such a device as flow regulator 18 may appear to impede the flow of air out of turbine shroud 14 and potentially reduce the available power of wind driving impellor 16. Experimentally however, the performance gained by maintaining a smooth flow of wind over concentrator wings 12 far outweigh the induced drag losses, when flow regulator 18 is positioned at a correct distance from turbine shroud 14 and within the high speed stream of air exiting same. As will be disclosed, this very property of inducing drag or restricting the wind flow exiting turbine shroud 14 may be used beneficially in wind energy extraction device 10 to provide aerodynamic braking in order to protect components of the present wind energy extraction device in conditions of gusting or very high speed winds. Fig. 5 therefore also schematically illustrates a cross section of the flow of wind over and between concentrator wings 12, through turbine shroud 14 and over aerodynamic surfaces 50 of flow regulator 18. Of note in Fig. 5 relative to Fig. 4 is the closer proximity of flow regulator 18 to turbine shroud 14. This closer proximity restricts the flow of wind out of turbine shroud 14 thereby acting to aerodynamically brake impellor 16 in the event of overly gusting or very high speed winds. Aerobrake 20 therefore includes flow regulator 18 and turbine shroud 14 and an adjustment of the proximity between flow regulator 18 and turbine shroud 14 to prevent impellor 16 or other components of wind energy extraction device 10 from overspeeding or exceeding other design limitations in gusting or very high speed winds. For the definition of aerobrake 20 and for general understanding it must be noted that turbine shroud 14 as illustrated is hereby defined as a special case of concentrator wing 12 that in the case of turbine shroud 14 is used in association with impellor 16. A device having aerodynamically active surfaces as described for concentrator wings 12 may as well be used as turbine shroud 14 and interact with flow regulator 18 to serve in the definition of aerobrake 20. An adjustment of the proximity of flow regulator 18 and turbine shroud 14 will now be described.

Fig. 2 provides a cross-sectional view of elements of wind energy extraction device 10 and in particular illustrates an adjustment of the proximity of turbine shroud 14 to flow regulator 18. Fig. 2, like Fig. 4 illustrates components of wind energy extraction device 10 in a non-aerobraked condition where turbine shroud 14 is in a far position relative to flow regulator 18. For convenience, the length of the relative far position is indicated by the letter "A". Fig. 3 provides an identical view with the exception that components of wind energy extraction device 10 are now in an aerobraked position where turbine shroud 14 is in a close position relative to flow regulator 18. In this instance, the length of this relative close position is indicated by the letter "B". Aerobrake 20 allows concentrator wings 12 or turbine shroud 14 to be pushed by the force of a gusting or high speed wind upon these elements. Concentrator wings 12 and turbine housing 14 are connected together by retainers 28, one of which is illustrated in Fig's 2 and 3. Retainer 28 then connects with collar 36 that is free to slide along lee support 32. Turbine shroud 14 is also connected to struts 40, one of which is illustrated in each of Fig's 2 and 3, struts 40 then connecting to another collar 36 that is free to slide on driveshaft housing 38 visible in Fig. 3. Referring now to Fig. 2, in conditions where the wind is not overly gusting or overly high speed, wind energy extraction device 10 will maintain a non-aerobraked condition with one of collar 36 pressing against compression spring 24. Fig. 3 then represents an aerobraked position where the force of the gusting or overly high speed wind is pushing against concentrator wings 12 or turbine housing 14 or other elements and causing collar 36 to compress compression spring 24 and slide in a downwind direction towards flow regulator 18 thus closing the gap between the outlet of turbine shroud 14 and aerodynamic surfaces 50 of flow regulator 18. Also of note is the position of impellor 16 relative to the inlet of turbine shroud 14 in the non-aerobraked condition as illustrated by Fig's 2 and 4, and the aerobraked condition as illustrated by Fig's 3 and 5. For very high wind conditions, it may be advantageous to include a catch mechanism (not illustrated) operating such that when compression spring 24 is compressed to some defined limit, this catch will not allow compression spring 24 to de¬ compress, and wind energy extraction device 10 will remain in an aerobraked condition until the catch is released. This may serve to further protect the moving elements in severe weather conditions.

Fig. 3 illustrates impellor 16 attaching to impellor driveshaft 26 that passes through and is free to rotate within driveshaft housing 38. Impellor driveshaft 26 then enters flow regulator 18 that may also be used to house power converter 22, typically an alternator or generator, used to convert mechanical torque into usable electrical energy. It is an object of the present wind energy extraction device to remove power converter 22 from the high speed flow passing by impellor 16. Prior wind turbines have been proposed where the alternator or generator must be faired in to minimize aerodynamic drag losses incurred by the necessary placement of these elements within the high speed wind flow. Impellor driveshaft 22 of the present wind energy extraction device extends impellor 16 into the high speed flow of wind drawn through turbine shroud 14 and as well allows power converter 22 to be enclosed within or on the lee or leeward side of aerodynamic surfaces 50 of flow regulator 18 and out of this high speed wind flow. Aerodynamic surfaces 50 on the windward side of flow regulator 18 work to direct the wind flow outwards from flow regulator 18 and towards the wind flowing over concentrator wings 12 and cause the formation of a 'dead' or slower moving airspace on the leeward side of flow regulator 18. This dead airspace provides an ideal location for power converter 22 especially when housed within flow regulator 18 and protected from weather and other elements of the natural environment.

In theory, and in practice, the highest energy extraction efficiency occurs when the wind is decelerated immediately downstream of a wind turbine to about 1/3 of its original free flowing velocity. This principle as well applies to shrouded wind turbines. This principle is applied in wind energy extraction device 10 and it is an object of the wind energy extraction device to mount and support elements of wind energy extraction device 10 to present little obstruction to the higher speed wind flow upstream of components of wind energy extraction device 10, and, at once allow wind energy extraction device 10 to orient into the oncoming wind and preferably without the assistance of motor drives or ancillary wind direction sensing instruments. With reference again to Fig. 2, downwind guidance 30 serves as such. Downwind guidance 30 includes lee support 32, a mounting element that supports concentrator wings 12, flow regulator 18, and other elements of wind energy extraction device 10, and extends in a downwind direction into the slower moving wind flow on the leeward side of concentrator wings 12. Lee support 32 then turns outward from the previously described central axis of wind flow and finally connects with swivel 34 that is mounted just forward of the center of wind pressure upon concentrator wings 12 and other elements of wind energy extraction device 10 to allow these elements to rotate about swivel 34 and be directed or preferably self-orient appropriately into the oncoming wind. Swivel 34 best includes sealed roller bearings that permit low friction rotation of swivel 34 and ensure a long operational life in an outdoor environment. Swivel 34 may also include a commutator plate (not illustrated) to conduct electrical power generated by power converter 22 through swivel 34 for further processing or utilization. Referring now to Fig. 7, care must also be taken to ensure that riser 42, which provides support to swivel 34 and as well extends elements of wind energy extraction device 10 into a freer unobstructed flow of wind, is mounted typically parallel to the local gravitational lines. Care must also be taken during design of embodiments of wind energy extraction device 10 to ensure that elements of wind energy extraction device 10 that are supported by swivel 34 are reasonably well balanced in a forward and aft direction to minimize any self-guidance error into the oncoming wind should riser 42 not be mounted exactly parallel to the local gravitational lines. Foundation 44 supporting riser 42 and other elements of wind energy extraction device 10 should as well be designed to accommodate the highest forces of wind anticipated for the region of installation. Fig. 7 as well indicates, by the use of arrows, the action of downwind guidance 30 around a common axis defined by swivel 34.

Fig. 8 illustrates an additional embodiment of a wind energy extraction device 10 that in this instance includes multiple impellors 16 and one or more power converters 22 (power converters 22 not visible in this view). Only a single power converter 22 is required for multiple impellors 16. The impellors 16 may be connected via pulleys, a transmission, or any of a variety of means to a single power converter 22. For example, as shown in Fig. 11, three impellors 16 may be connected to a single power converter 22. Also of note in this figure are concentrator wings 12 that appear as straight sections rather than the curved sections of the previous figures. Swivel or swivels 34 are also indicated that as well serve to orient elements of wind energy extraction device 10 appropriately into the oncoming wind. Also of note in Fig. 8 is flow regulator 18 that runs, in this embodiment, the full length of multiple impellors 16, rather than only downwind of a single impellor 16 as illustrated in previous figures. Impellor driveshafts 26 (not indicated in this view) as well extend from flow regulator 18 to position impellors 16 into the higher speed wind flowing through turbine shroud 14. Again to clarify, the function of turbine shroud 14 may as well be served by concentrator wings 12 in closest proximity to impellors 16. Fig. 9 then illustrates a cross-section through the additional embodiment of wind energy extraction device 10 as introduced by Fig. 8. In this instance, and for additional clarity, two additional concentrator wings 12 serve as turbine shroud 14 as the aerodynamic elements in closest proximity to impellor 16. Power converter 22 is also indicated in this view again located, as in previous figures, downwind, or on the opposite side of aerodynamic surfaces 50 of flow regulator 18. The use of multiple power converters 22 and multiple impellors 16 has several important advantages. Relatively smaller impellors 16 allow higher operating rpm's which in turn allow power converters 22 to be directly driven and also operate at relatively higher rpm's. In general, higher rotating speed alternators or generators require fewer windings and are less costly in production. Another important aspect relates to overspeed protection. Clearly, where the number of impellors 16 and power converters 22 is increased relatively to some fixed area of wind capture, the work of converting the wind energy to usable electrical energy is shared and reduced for each individual impellor 16 and power converter 22. It also follows that the work of preventing overspeeding of impellors 16 and power converters 22 is shared over larger numbers of these elements. The electrical or magnetic resistance of an alternator, as an example of a suitable form of power converter 22, is familiar to most people who operate automobiles. When such a vehicle is idling and some additional electrical load is applied, such as headlamps, the engine may be experienced to idle down. This occurs as a result of the engine having to work harder to revolve the alternator that now applies a greater electrical or magnetic resistance in response to the greater demand made upon it to provide electricity to the headlamps. This same electrical or magnetic resistance may be applied to power converter 22 to produce additional electricity and at the same time control the rotational speed of power converter 22 in higher wind conditions. Again, increasing the number of power converters 22 with respect to some fixed area of wind capture of wind energy extraction device 10 provides a greater ability to apply braking or overspeeding of impellors 16 and power converters 22. Riser 42 is also indicated in this view running downwind, or on the opposite side, of aerodynamic surfaces 50 of flow regulator 18. This is more than a convenient location for riser 42 as such a location allows riser 42 to support elements of wind energy extraction device 10 and at once to reduce aerodynamic drag losses that would otherwise be incurred by riser 42. Alternate downwind guidance 46 therefore provides an alternate to downwind guidance 30 in this embodiment whereby alternate downwind guidance 46 includes riser 42 running downwind, or on the opposite side, of aerodynamic surfaces 50 of flow regulator 18 and as well includes swivel or swivels 34. Swivel 34, in this event, is preferably located sufficiently upwind, relative to other elements of wind energy extraction device 10, such that the forces of wind alone will cause elements of wind energy extraction device 10 to orient appropriately into the oncoming wind without motor drive or other assistance.

Fig. 10 provides two perspective views of an additional embodiment of wind energy extraction device 10. The circular arrows serve to indicate the motion of alternate downwind guidance 46 as elements of wind energy extraction device 10 rotate about swivel or swivels 30 to face the oncoming wind. Lamp 48 is also indicated in Fig. 10 to provide an example of configuring wind energy extraction device 10 as a dual use lamp standard and wind/electric generator, which may be used alongside a roadway such as along a city street, highway, or highway intersection, where lamp 48 is used to illuminate the roadway or roadway intersection and the wind/electric generator components to provide electricity to lamp 48 or to the electricity utility grid. Riser 42, remaining stationary with respect to concentrator wings 12 permits the stationary mounting of lamp 48 irrespective of the wind direction or the orientation of concentrator wings 12 into the oncoming wind.

Fig. 11 provides an additional view of two of the wind energy extraction systems each having two sets of concentrator wings 12 and three impellors 16. Fig. 11 also indicates insulator 50 mounted on top of riser 42, and transmission line 54 connecting the two wind energy extraction systems together and together with utility power pole 52. Utility power pole 52 as illustrated permits interconnection with the electricity utility grid. Riser 42 extending above concentrator wings 12 permits insulator 50 to carry transmission line 54 high above ground level. Again, riser 42 being stationary and independent of the orientation of concentrator wings 12 permits the stationary mounting of insulator 50 on top of riser 42. The carriage of transmission line 54 high above ground level allows the passage of farm machinery under transmission lines 54 where installed on agricultural land, and avoids the additional costs and hazards of burying cable underground.

The illustrations as well help to clarify the benefit of minimizing the diameter of the inlet to turbine shroud 14 and the diameter of impellor 16 relative to the larger diameters or capture areas of concentrator wings 12. The larger diameter concentrator wings 12, or larger capture areas afforded by concentrator wings 12, allow wind energy extraction device 10 to capture and extract energy from a large area of wind relative to the frontal area of turbine shroud 14, and at the same time present a highly noticeable object to birds in flight. Concentrator wings 12 may also be made more noticeable by application of contrasting colors, shades or patterns made on these elements for installations of embodiments of wind energy extraction device 10 within relatively featureless landscapes as are found within prairies or deserts. The use of markings and colorings may also improve the blending of embodiments of wind energy extraction device 10 within other highly textured natural landscapes without creating a hazard for birds in flight. For example, considering a wind farm having embodiments of wind energy extraction device 10 that have varied textures and colorings similar to those of the surrounding forest, the wind turbines would appear to birds as a raised section or hill having the same textures as trees of the surrounding forest, and at the same time allow the wind turbines to visually blend into the forest landscape. The smaller diameters of turbine shroud 14 easily lend to the screening over of the inlet to this element should this be proven necessary. In all likelihood however, this will not be necessary for the aforementioned reasons.

In general, wind turbines having large rotor blade diameters of 80 meters or longer are unable to extract additional energy from winds exceeding 25 or 30 mph. In other words, the same amount of energy will be extracted from a wind of 25 mph as will be from a wind of 35 mph. This is a significant loss of potential energy given that power available in a wind increases to the cubic power of the wind velocity. These machines as well must be entirely shut down, rotor blades brought to a complete stop, at wind speeds about 45 or 50 mph. In winds generally greater than 25 mph, the long rotor blades of popular wind turbine designs develop tremendous forces that act on the blades themselves and upon the transmissions, bearings, braking systems and support structures of these machines. This is an important consequence when considering that the available power in a 35 mph wind approaches three times (2.74) the power available in a 25 mph wind, the top of the power generation curve for typical large rotor blade diameter wind turbines, wind energy extraction device 10, because of flow regulator 18 is able to present a large frontal area to the oncoming wind while at once minimizing the size of rotor blades or impellor 16. By using smaller diameter rotor blades, embodiments of wind energy extraction device 10 are able to run impellor 16 at substantially higher rpm's and efficiently extract energy from significantly higher wind speeds as compared with popular wind turbines having large diameter rotor blades. As previously stated, shrouded wind turbines that do not include flow regulator 18 are not able to process these higher speed winds or even to provide a higher ratio of shroud diameter to impellor diameter without experiencing the stalling of the shrouds as described.

Finally, due to the overall design of wind energy extraction device 10, and in particular to the introduction of aerobrake 20 and downwind guidance 30, and the relatively smaller impellor 16 and turbine shroud 14, design, production and maintenance costs and expenses may all be reduced relative to current wind turbine designs. The terms of 'air' and 'wind' are used throughout this application to denote a fluid as it is understood and defined in the art and practice of fluid dynamics. Although the primary intent of wind energy extraction device 10 is for the extraction of energy from wind, the principles and innovations may apply equally to the flow of other fluids, and in particular to flowing water, also considered abundant sources of naturally renewing energy. The multiple impellor design also has utility where a single concentrator wing is used, although this design is not as efficient as the design where plural concentrator wings are used.

The preceding descriptions serve to explain the main objects and advantages of wind energy extraction device 10. Immaterial modifications may be made to the embodiments described without departing from the invention.

Claims

What is claimed is:

1. A wind energy extraction device, comprising: an impellor and associated power converter for the impellor; concentrator wings disposed about the impellor, the concentrator wings being spaced apart to permit air flow between the concentrator wings; the impellor being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings; and a flow regulator positioned downstream of the impellor, the flow regulator having wind deflecting aerodynamic surfaces that are contoured to enhance laminar flow of the air flow between the concentrator wings.

2. A wind energy extraction device, comprising: plural impellors and at least one associated power converter for the impellors; concentrator wings disposed about the impellors, the concentrator wings being spaced apart to permit air flow between the concentrator wings; and the plural impellors being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings.

3. The wind energy extraction device of claim 2, further comprising a flow regulator positioned downstream of the plural impellors, the flow regulator having wind deflecting aerodynamic surfaces that are contoured to enhance laminar flow of the air flow between the concentrator wings.

4. The wind energy extraction device of claim 1, 2 or 3 in which the one or more impellors are disposed within a turbine shroud.

5. The wind energy extraction device of claims 1, 2, 3 or 4 in which the concentrator wings are concentrically disposed to each other about a central axis.

6. The wind energy extraction device of claim 5 in which the one or more impellors are located on the central axis.

7. The wind energy extraction device of claim 4 further comprising an aerobrake arranged such that the proximity of the turbine shroud to the flow regulator may be adjusted depending on wind conditions.

8. A wind energy extraction apparatus comprising one or more concentrator wings that react with a flow of wind to induce a drop in static air pressure that is then used to drive one or more impellors and one or more power converters; and a flow regulator having aerodynamic surfaces directing a flow of wind impinging upon said flow regulator outwards from said flow regulator and towards a said flow of wind reacting with said one or more concentrator wings.

9. The wind energy extraction device of claim 4 or 8 wherein the one or more power converters are installed on the downwind side of the aerodynamic surfaces of the flow regulator; and further comprising one or more impellor driveshafts connecting each of the one or more impellors to the one or more associated power converters, the impellor driveshafts extending out of the flow regulator and positioning the impellor within the flow of wind passing through the turbine shroud.

10. The wind energy extraction apparatus of claim 9 wherein more than one said power converters are positioned on the leeward side of said aerodynamic surfaces of said flow regulator; and further comprising more than one impellor driveshafts connecting more than one said impellors to more than one said power converters, said more than one impellor driveshafts extending out of said flow regulator and positioning more than one said impellors within the flow of wind passing through said turbine shroud, such that more than one said power converters operate in concert to control the rotational speed of more than one said power converters.

11. The wind energy extraction apparatus of any one of claims 1-10 further comprising a downwind guidance for supporting a plurality of elements to include at least said one or more concentrator wings and said flow regulator, said downwind guidance presenting little obstruction to the higher speed wind flow upstream of said elements, said downwind guidance facilitating the orientation of said plurality of elements approximately into the oncoming wind and said downwind guidance comprising a lee support that supports said plurality of elements and extends in a downwind direction then turns outward and connects with a swivel that allows said plurality of elements to rotate around a common axis and effect said orientation.

12. The wind energy extraction apparatus of any one of claims 1-11, further comprising an alternate downwind guidance for supporting a plurality of elements to include at least said one or more concentrator wings and said flow regulator, and for facilitating the orientation of said plurality of elements appropriately into the oncoming wind; and further comprising a riser to extend the said plurality of elements into said oncoming wind, at least a part of said riser extending on the leeward side of said aerodynamic surfaces of said flow regulator; and further comprising at least one swivel to allow said plurality of elements to rotate about said swivel and effect said orientation.

13. The wind energy extraction apparatus of any one of claims 1-12 in which the concentrator wings are elongated in the vertical direction when mounted.

14. The wind energy extraction device of any one of claims 1-13 mounted on a lamp standard adjacent a roadway.

15. A method for extracting energy from wind, comprising the steps of: causing wind to flow over one or more concentrator wings and thereby inducing a drop in static air pressure; using said drop in static pressure to draw a flow of wind into a turbine shroud; using said flow of wind to drive one or more impellors; directing said flow of wind impinging upon the windward side, of aerodynamic surfaces of a flow regulator, outwards from said flow regulator and towards the flow of wind over said concentrator wings.

16. The method of claim 15 further comprising: positioning one or more power converters on the leeward side, of said aerodynamic surfaces of said flow regulator; connecting said one or more impellors to one or more impellor driveshafts; extending said one or more impellor driveshafts out of said flow regulator; positioning said one or more impellors within the said flow of wind drawn into said turbine shroud.

17. The method of claim 16 further comprising: positioning more than one power converters on the leeward side of said aerodynamic surfaces of said flow regulator; connecting more than one said impellors to more than one impellor driveshafts; extending more than one said impellor driveshafts out of said flow regulator; positioning more than one said impellors within the said flow of wind drawn into said turbine shroud such that more than one said power converters work in concert to control the rotational speed of more than one said power converters.

18. The method of claim 15 further comprising: adjusting the proximity of said turbine shroud to said flow regulator to control the flow of wind through said turbine shroud.

19. The method of claim 15 further comprising: supporting at least the elements of said one or more concentrator wings and said flow regulator by use of a lee support that extends in a downwind direction then turns outward and connects with a swivel that allows said elements to rotate around a common axis to align appropriately into the wind.

20. The method of claim 15 further comprising: supporting at least elements of said one or more concentrator wings and said flow regulator by a riser; extending at least a part of said riser along the leeward side of said aerodynamic surfaces of said flow regulator; facilitating the rotation of said elements by a swivel that allows said elements to rotate around a common axis in order to effect appropriate alignment of said elements into the oncoming wind.

21. A method for extracting energy from wind, the method comprising the steps of: driving an impellor using a flow of wind induced by air flow between concentrator wings, the impellor being connected to a power converter; and deflecting the flow of wind using aerodynamic surfaces of a flow regulator to enhance laminar flow of the air flow between the concentrator wings and thereby reduce aerodynamic stalling of one or more of the concentrator wings.

22. The method of claim 21 in which the impellor is disposed within a turbine shroud.

23. The method of claim 22 further comprising adjusting the proximity of the turbine shroud to the flow regulator according to wind conditions.

24. The method of claim 23 in which adjusting the proximity of the turbine shroud to the flow regulator comprises reducing the proximity in high wind conditions to impede or restrict the flow of wind through the turbine shroud.

25. The method of claim 24 in which the power converter is located coaxially with the impellor and downwind of the flow regulator.

26. The method of claim 27 further comprising the concentrator wings being pivotally mounted to allow the concentrator wings to align with wind direction.

27. The method of claim 26 in which the concentrator wings are pivotally mounted on a swivel connected to the concentrator wings by a lee support.

28 . The method of claim 21 in which the power converter is located coaxially with the impellor and downwind of the flow regulator.

29. A wind energy extraction device, comprising: an impellor and associated power converter for the impellor; concentrator wings disposed about the impellor, the concentrator wings being spaced apart to permit air flow between the concentrator wings; the impellor being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings; and the concentrator wings being mounted on a lamp standard alongside a roadway.

30. A wind energy extraction device, comprising: an impellor and associated power converter for the impellor; concentrator wings disposed about the impellor, the concentrator wings being spaced apart to permit air flow between the concentrator wings; the impellor being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings; and the concentrator wings being mounted on a lamp standard oriented vertically and being elongated in a vertical direction.

31. The wind energy extraction device of claim 30 further comprising multiple impellers positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the air flow between the concentrator wings.

32. A wind energy extraction device, comprising: at least one impellor and associated power converter; concentrator wings disposed about the impellor, the concentrator wings being spaced apart to permit air flow between the concentrator wings; the impellor being positioned in relation to the concentrator wings to be driven in use by a flow of wind induced by the airflow between the concentrator wings; and a stationary riser supporting a plurality of elements and supporting on top of the stationary riser an insulator supporting a transmission line that permits the electrical interconnection of multiple wind energy extraction devices and interconnection of a utility power pole.

33. A wind energy extraction device, comprising: plural impellors and at least one associated power converter for the impellors; a concentrator wing disposed about the impellors; and the plural impellors being positioned in relation to the concentrator wing to be driven in use by a flow of wind induced by the air flow over the concentrator wing.