Abstract: Aircraft nacelles having adjustable chines are described. An example apparatus includes a multi-segment chine rotatably coupled to a nacelle. The multi-segment chine includes at least two segments. The at least two segments include a first segment and a second segment. The first segment and the second segment are independently rotatable relative to the nacelle about an axis of rotation.

Abstract: A wind turbine including a plurality of elements including a tower, a nacelle mounted to the tower and a plurality of blades rotatable mounted to the nacelle is provided. At least one element of the tower, the nacelle and the blades includes a coaxial impedance member coaxially arranged about an axis of the element.

Abstract: Wind turbine systems with wind directors are disclosed. The wind director is configured to simultaneously reduce drag force applied to a returning blade and increase force applied to an advancing blade. In some embodiments, the wind director includes an inlet having an inlet width configured to receive wind at a proximal end, and an outlet having an outlet width on a distal end opposite the proximal end. The wind director is configured to position near a wind turbine such that wind exiting the outlet is applied to an advancing blade of the wind turbine. Furthermore, the wind director provides a barrier to a returning blade opposite the first blade, thereby reducing drag force applied thereto. The wind director may further comprise a secondary duct which has an angled outlet and is configured to apply an additional force to the returning blade.

Abstract: The present invention relates to an electric power system for converting wind energy into electric energy, comprising a duct for air, the duct comprising a floor, a first and a second wall, a roof, defining an air inflow direction towards, a turbine having a diameter, and being located adjacent to or at least partially in the duct; and defining together with the duct an air outflow direction wherein an area free of pressure and/or turbulence increasing obstructing elements, extending in the resultant air outflow direction of the turbine over a length of at least one, and preferably more than two times the turbine diameter, measured from the centre of rotation of the turbine. The invention further relates to a building comprising such system.

Abstract: Methods and systems are described for an aerial drone system including a drone system controller, at least one working drone (101), and a plurality of support drones (103). The working drone (101) is operated by the drone system controller (125) to adjust a position of the working drone (101). A tether line (105) coupled to the working drone (101) provides electrical power to the working drone (101). The support drones (103) are each coupled to the tether line (105) at a different location along the tether line (105) forming a tethered aerial drone system. Each support (drone 103) supports a portion of the weight of the tether line (105) and is operated by the drone system controller (125) to adjust the position of the tether line (105) by adjusting the position of one or more of the support drones (103).

Abstract: Systems and methods for increasing lift of an aircraft lifting surface, may include: a leading-edge assembly; a plurality of high-lift propellers, coupled to the slat assembly and configured to be stowed within a compartment of the lifting surface; a high-lift motor to provide motive force to at least one of the plurality of the high-lift propellers; and a deployment linkage configured to move the slat assembly and plurality of high-lift propellers between a deployed configuration and a stowed configuration, wherein in the stowed configuration the high-lift propellers are stowed within the compartment of the lifting surface and at least a portion of the slat assembly covers the compartment of the lifting surface, and in the deployed configuration the high-lift propellers are positioned external to the aircraft lifting surface to direct airflow from the high-lift propellers past the leading-edge assembly.

Abstract: Systems and methods relate to a vertical takeoff and landing (VTOL) platform that can include a stator and a rotor magnetically levitated by the stator. The rotor and stator can be annular, such that the rotor rotates about a rotational axis. The stator can include magnets that provide guidance, levitation, and drive forces to drive the rotor, as well as to control operation of rotor blades of the rotor that can be independently rotated to specific pitch angles to control at least one of lift, pitch, roll, or yaw of the VTOL platform. Various controllers can be used to enable independent and redundant control of components of the VTOL platform.

Abstract: The invention relates to a method for monitoring performance of a multi-rotor wind turbine. According to the method parameter for each of the wind turbine modules of the multi-rotor wind turbine is obtained. The parameters of each of the wind turbine modules are compared, e.g. by means of a comparison parameter determined from the individual parameters. Dependent on the result of the comparison, a performance action is initiated, e.g. for the purpose of further characterization or verification of a deviating parameter determined via the comparison.

Abstract: There is presented a wind turbine system, wherein the wind turbine system is comprising a support structure, a plurality of wind turbine modules mounted to the support structure wherein each of the plurality of wind turbine modules comprises a rotor, and wherein the wind turbine system further comprises a control system, wherein the control is arranged to execute a wind turbine system transition from a first system operational state of the wind turbine system to a second system operational state of the wind turbine system, and wherein the wind turbine system transition is performed by executing a plurality of wind turbine module transitions from a first module operational state of a wind turbine module to a second module operational state of the wind turbine module wherein the plurality of wind turbine module transitions are distributed in time with respect to each other.

Abstract: Aspects of the present disclosure are generally directed to using a rotary transformer to transfer power for a wind turbine generator. Certain aspects of the present disclosure are directed to a multi-rotor wind turbine. The multi-rotor wind turbine generally includes a plurality of rotors, a plurality of electrical generators, each coupled to one of the plurality of rotors, and one or more rotary transformers configured to transfer power between the electrical generators and a power grid. In some aspects, each rotary transformer comprises a first winding coupled to one or more electrical generators of the plurality of electrical generators, and a second winding magnetically coupled to the first winding and coupled to the power grid, wherein the first winding is rotatable with respect to the second winding.

Abstract: A wind turbine system is described comprising a plurality of wind turbine modules, each including a rotor, mounted to a support structure including a tower. In use, each rotor has an associated rotating unbalance that defines an unbalance vector. The wind turbine system includes control means configured to coordinate the rotational speeds of the plurality of rotors to attenuate oscillations of the support structure caused by the rotating unbalance of the rotors. Also described is a method of controlling such a wind turbine system. The method comprises coordinating the rotational speeds of the plurality of rotors to attenuate oscillations of the support structure caused by the rotating unbalance of the rotors.

Abstract: A vertical axis wind turbine includes a cylindrical rotor with a plurality of convex-concave blades placed in a stator which directs the wind stream. The VAWT is installed vertically towards a surface of the ground, and wherein, the stator and the rotor are formed of vertically located blades which may have numerous geometric forms. Both the stator and rotor blades have a leading edge and a trailing edge, and each blade of the stator possesses a top end that is fastened to an immobile upper plate of the stator, and a bottom end that is fastened to a lower plate of the stator. In this embodiment, each blade of the rotor includes a top end fixed to an upper plate, while a bottom end of the each blade is fixed to a lower plate.

Abstract: The bearings of aircraft angle of attack (AOA) vanes are susceptible to lightning strike damage, which causes fluting on the inner and outer races of the bearings and causes the bearings to generate friction, noise, and vibrations. To prevent the bearings from experiencing damage due to lightning strikes, the bearings, the shaft, and/or the mounting plate are configured to create an electric isolator to prevent the electric current from the lightning strike from passing through the bearings, thereby preventing the bearings from incurring lightning strike damage.

Abstract: A turbine with flow diverter comprises a support frame adapted to be anchored to a fixed or movable structure, an impeller rotatably mounted about a rotation axis to the support frame and having a front inlet section for receiving the flow and adapted to move continuously upon the rotation produced by the flow between a pushing position and an advancing position in correspondence of the front section, a main flow diverter adapted to be anchored to the support frame and having a peripheral wall adapted to at least partially blind the front section with respect to the flow auxiliary diverter extending from a first section facing one or more blades in the advancing position to a second section facing one or more blades in pushing position. The auxiliary diverter comprises curvilinear conduits in reciprocal side by side position along a radial direction.

Abstract: The present invention is a hydroelectric system having a siphon component, a generator component, and an electronics and control component, which produces an inflow of water caused by a vacuum initially created within the system and further aided by hydrostatic pressure. The inflow is directed to a ramp where it drives a water turbine located within the respective electrical generating system to produce electrical power.

Abstract: A wind turbine for capturing energy from a fluid flow comprises a rotor having a rotational axis and a plurality of rotor blades 104 arranged for rotation about the rotational axis. The rotor blades extend longitudinally in a direction substantially parallel to the rotational axis. A shield member V3 is arranged to shield some of the rotor blades from an oncoming wind where incidence of the wind on those rotor blades would act against rotation of the rotor in the direction of rotation. The rotor blades 104 are distributed about the circumference of the rotor and are spaced from the rotational axis, defining a substantially cylindrical space within the rotor through which the wind passes. The shield member V3 is defined by a radially inward surface and a radially outward surface. The radially inward surface follows substantially a portion of the circumference of the rotor. The radially outward surface of the shield member V3 comprises a first portion which meets the radially inward surface.

Abstract: A structural duct apparatus includes a cross flow turbine for use in a fluid flow. The turbine has at least one straight vertical aerofoil blade and at least one helical aerofoil blade slanted toward the direction of rotation. Inner and outer walls of the duct apparatus provide an inner diffuser flow passageway that houses turbine power take off modules with the outer surfaces of the duct influencing flow direction so that where there are at least two ducts an open flow barrage is advantageously formed.

Abstract: A system is provided to determine whether an insulating layer of an implanted lead is damaged.

Abstract: A segmented gear plate configured to be removably connected to a pitch bearing of a wind turbine has been described. The pitch bearing is present between a rotor hub and a plurality of blades. The pitch bearing axially pivots the plurality of blades between different pitch angles. The pitch bearing includes an inner bearing ring and an outer bearing ring rotatably interconnected to each other. The segmented gear plate is removably connected to at least one of the inner bearing ring or the outer bearing ring by at least one connecting element. The segmented gear plate having a plurality of gear teeth, the plurality of gear teeth configured to allow the rotation of a drive shaft of a motor to achieve different pitch angles.

Abstract: A vertical-axis wind turbine apparatus is disclosed. In at least one embodiment, the apparatus provides a substantially vertically-oriented main shaft. A blade assembly is coaxially aligned with and rotatably engaged about the main shaft. The blade assembly provides an at least one blade radially projecting therefrom. A housing is rotatably engaged with the main shaft and configured for selectively encompassing the blade assembly. A first screen is integral with the housing and configured for shielding a return portion of the blade assembly. A second screen is rotatably engaged with the housing and configured for selectively moving between a retracted position, wherein the second screen is positioned substantially adjacent to the first screen such that a catch portion of the blade assembly is exposed, and a deployed position, wherein the second screen is rotated away from the first screen for at least partially shielding the catch portion from the wind.

Abstract: An electrical power generating system includes a wind deflecting structure having a contour at a proximal end formed by a plurality of sail segments that in a first position define the contour, a turbine positioned in proximity to a distal end of the wind deflecting structure such that the turbine is driven by wind passing around the wind deflecting structure, and an energy converter coupled to the turbine that converts rotary motion from the turbine into electrical energy, wherein at least one of the plurality of sails is movable between the first position defining a corresponding portion of the contour of the wind deflecting structure and a second position that reduces a wind drag coefficient of the wind deflecting structure.

Abstract: An oscillating foil turbine has a foil having a first fluid dynamic surface for producing lift in a fluid flow, a support for the foil, and a second fluid dynamic surface, wherein the support allows for cyclic motion of the first and second surfaces with respect to each other. A driven member is provided to tap energy from flow throughout each cycle. Throughout at least part of the cyclic translation, the fluid dynamic surfaces are oriented sufficiently parallel, and separated by a distance that is sufficiently small, to achieve a substantial wing-in-ground effect.

Abstract: An energy converter for converting kinetic energy from a body of liquid by transverse galloping includes a support, an elongate galloping body extending between a first end and a second end and being of a suitable cross-section for transverse galloping, a substantially horizontal guide arranged outside the body of liquid for guiding the first end of the galloping body, one or more elastic means substantially horizontally arranged and connected between the galloping body and the support, and a generator including a static generator component and a dynamic generator component, and wherein the galloping body is substantially vertically suspended such that the second end of the body extends into the body of liquid, and the dynamic generator component is operationally connected to the galloping body. Further disclosed are energy conversion systems including a plurality of energy converters and methods for energy conversion.

Abstract: A transverse axis fluid turbine with controllable display components thereof is disclosed. The turbine has a base structure, rotor rotatably attached to the base structure and at least three blades rotatably attached to the rotor. A matrix array of light reflective or emitting elements is mounted on the flat blade surface. The light reflective or emitting elements are controlled by a control unit in such a way that the light reflecting or emitting provides stable still or moving image(s) to its viewer(s) while the turbine is in operation.

Abstract: An apparatus for converting fluidic flow into electrical energy includes a focusing chamber through with fluidic flow enters, a fin diverter positioned adjacent an entrance of the focusing chamber, a constricting chamber positioned adjacent a downstream end of the focusing chamber having a flow passage that converges in a frustum shape, a streamliner positioned adjacent an outlet end of the constricting chamber, an extraction chamber positioned adjacent the streamliner, an energy converter driven by the fluidic flow passing through the extraction chamber for producing electrical energy, and a diffusing chamber positioned to receive at an inlet end the fluidic flow passing out of the extraction chamber, the diffusing chamber having a flow passage that diverges from the inlet end of the diffusing chamber to an exhaust end at which the fluidic flow exits the apparatus.

Abstract: A wind turbine able to generate power irrespective of a presence of and a state of a power grid is disclosed. Specifically, a wind power generation system is provided with a wind turbine, the wind turbine including a blade that rotates in response to the wind, a generator that rotates with rotation of the blade to generate power, and an auxiliary machine that controls a pitch angle of the blade. The auxiliary machine is driven by the generated power of a downwind type wind turbine to which a permanent magnet type generator is mounted and which generates power in a state in which a blade of the downwind type wind turbine rotating in response to the wind faces downwind.

Abstract: An apparatus for generating electricity using water flow in a body of water comprises: an array of spaced apart elements. Each element defines an elongate flow passage and has an upstream side and an elongate downstream side, each element being provided with a series of holes spaced along its length and the downstream side extending and tapering away in the direction of flow. The elements are arranged side by side such that opposing walls of adjacent elements define a venturi section and a first diffuser section extending downstream from the venturi section. The apparatus also comprises:—a flow conduit having an inlet and an outlet;—a turbine located in the flow conduit;—and a generator connected to the turbine; The flow passages are connected to the outlet of the flow conduit such that the flow of water through the venturi sections causes water to be drawn through the flow conduit out via the holes the resulting flow driving the turbine.

Abstract: Disclosed herein is a variable blade type tidal and wind power generator with increased generation efficiency. The tidal and wind power generator includes an installation frame (10), a vertical rotating shaft (20), blade installation bars (30) and (30?), support rings (40) and (40?), vertical support rods (50); rotor blades (60) and (60?), vertical support frames (70), horizontal frames (80), an installation member (20?), a support wire (50?), a blade-spreading-degree control means (90), a generation efficiency enhancing means (100) and a generation means (200) which is coupled to the lower end of the vertical rotating shaft to generate power. The tidal and wind power generator can be operated even in conditions of gentle winds or low tides regardless of the direction of the wind or the tidal flow.

Abstract: The invention relations to hydroelectric power industry and can be used for capturing the energy stored within atmospheric moisture at any locations worldwide. The device comprises a tail race (1), a head race (2), a water conduit (3), a turbogenerator (4), meshed, woven or filmed surfaces (5), an airship (6), and fastening cables (7). The airship (6) raises the surfaces (5) to the altitude above the dew point corresponding to the given atmospheric conditions (usually, 2-3 km). There, are supercooled atmospheric moisture starts to condense (accumulate) actively on the surfaces (5). A drainage system provided on the surfaces (5) takes this water to a small reservoir (head race 2), from which the water, under a head caused by the entire altitude level difference, passes along the water conduit (3) into the tail race (1) on the ground, thereby producing electrical power in the turbogenerator (4).

Abstract: A fluid turbine comprises a turbine shroud and an optional ejector shroud. The turbine shroud and/or the ejector shroud are formed from a hard shell and a membrane. The hard shell forms a leading edge, a trailing edge, and an interior surface of the shroud. The membrane forms an exterior surface of the shroud. The resulting construction is lighter than previous turbine shrouds.

Abstract: Example embodiments are directed to shrouded fluid turbines that include a turbine shroud and a rotor. The turbine shroud includes a plurality of mixer elements and the rotor can be disposed within the turbine shroud. The shrouded fluid turbine further includes a hybrid yaw system having a passive yaw system and an active yaw system for regulating a yaw of the shrouded fluid turbine. The hybrid yaw system further includes a torque limiter. Example embodiments are also directed to methods of yawing a shrouded fluid turbine. Example embodiments are further directed to hybrid yaw systems for a shrouded fluid turbine that includes a shrouded fluid turbine assembly rotationally engaged with a tower. The hybrid yaw system includes a passive yaw system and an active yaw system associated with the shrouded fluid turbine.

Abstract: Disclosed is a nacelle for a wind turbine which includes a generator, a load-carrying structure, a support structure, an electrical system, a yaw system, a control system and a housing. The generator includes a rotating part and a stationary part and the stationary part is connectable to the load-carrying structure. The load-carrying structure includes the yaw system and the control system. The support structure includes the electrical system and the support structure is connectable to the load-carrying structure. The housing is segmented and is connectable to at least the load-carrying structure. The generator, the load-carrying structure and the support structure are separate modules and the separate modules and the segmented housing are connectable at an erection site of the wind turbine to build the nacelle.

Abstract: A two-row tapered roller bearing includes an outer ring (1) having an outer diameter of at least one meter, a first inner ring (2) and a second inner ring (3) that is disposed axially adjacent the first inner ring (2). A first set of conically-formed roller bodies (4) roll between the outer ring (1) and the first inner ring (2) and a second set of conically-formed roller bodies (5) are disposed axially adjacent the first roller bodies (4) and roll between the outer ring (1) and the second inner ring (3). A first sealing ring (11) is disposed axially adjacent the outer ring (1), is connected with the outer ring (1) and slips on a slip surface (16) of the first inner ring (2) in a contacting manner.

Abstract: Various fluid turbine systems and methods are described. The turbine can be a vertical axis wind turbine configured to generate power from wind energy. The turbine system can have a blade assembly. The blade assembly can have a plurality of blades rotatable about an axis. The turbine system can have a concentrator positionable upwind and in front of a return side of the blade assembly. The concentrator can define a convex surface facing the wind. The turbine system can also have a variable concentrator positionable upwind of a push side of the blade assembly. The variable concentrator can be adjustable between a first position and a second position, the variable concentrator being capable of deflecting more wind toward the turbine in the first position than in the second position.

Abstract: A rotary, fluid-flow-to-mechanical/electrical power-conversion device including a generally cup-shaped, squirrel-cage rotor having a rotational axis, and including plural, circumferentially spaced, elongate, transverse-cross-sectionally arcuate airfoil (fluid-foil) blades sized and disposed about the rotational axis of the rotor with their respective long axes substantially paralleling the mentioned rotational axis. Blade-related dimensions and spacings are chosen whereby the ratio of blade-to-blade circumferential spacing a to blade transverse chord length b is characterized as one which: (a) resides in the general range of about 0.24 to about 0.4; or (b) resides, more preferably, within the somewhat narrower subrange of about 0.25 to about 0.35 within the mentioned general range; or (c) has, even more preferably (for use in many if not most circumstances), a value of about 0.33.

Abstract: A vertical axis wind turbine installed on the top floor of a residential building, particularly in an urban area, is provided with a rotor fitted with blades and actuated by the wind, thus driving a generator to provide electrical power. The wind turbine includes a wind-channelling base which extends through a funnel, particularly a diverging tapered funnel, at the neck of which the rotor is placed. The rotor includes a median channelling hub mounted on the inner part of the neck of the funnel.

Abstract: There is a Rogallo wing having an aerodynamic sheet having a leading end and a trailing edge. The trailing edge is curved to form a sheet of increasing concavity away from the leading edge. At least two folded edges extend between the leading end and the trailing edge are on opposed sides of the aerodynamic sheet, the two folded edges comprising integral ribs. A wind energy extraction apparatus comprises 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 impellers and one or more power converters. The one or more concentrator wings are Rogallo wings.

Abstract: A windpower generator apparatus having a rotor with an axis of rotation placed in a frame adapted to a ridge of a roof. The frame has a pair of deflectors suitable for focusing air flow toward the rotor. Each of the deflectors has a pair of side walls, an upper wall and a lower wall defining a tunnel narrowing toward the rotor. The pair of deflectors having parts respectively at the upper walls and the lower walls so as to conform to a slope of the roof and to maintain a same ratio between openings at opposite ends of the deflectors.

Abstract: A wind power generator is provided in which a reduction in weight is achieved by reducing the wall thickness of a nacelle, and an increase in the amount of heat input to the interior of the nacelle from sunlight is suppressed. In a wind power generator in which driving/power-generating mechanisms linked to a rotor head to which wind-turbine blades are attached are accommodated and installed inside a nacelle, a coating of high-reflectivity paint is formed on at least part of the outer wall that receives sunlight.

Abstract: Various fluid turbine systems and methods are described. The turbine can be a vertical axis wind turbine configured to generate power from wind energy. The turbine system can have a blade assembly. The blade assembly can have a plurality of blades rotatable about an axis. The turbine system can have a concentrator positionable upwind and in front of a return side of the blade assembly. The concentrator can define a convex surface facing the wind. The turbine system can also have a variable concentrator positionable upwind of a push side of the blade assembly. The variable concentrator can be adjustable between a first position and a second position, the variable concentrator being capable of deflecting more wind toward the turbine in the first position than in the second position.

Abstract: An underwater generator for generating electricity including: a casing, a turbine propeller assembly configured within the casing; a platform, where the platform provides a mechanism to hold the casing; a cover member, where the cover member protects the turbine propeller assembly; and a power cable for transmitting electrical energy from the underwater generator to a user thereof. The casing may include a slit at a bottom portion, where the slit allows the removal of sediments, sand particles and similar materials. The turbine propeller assembly includes a plurality of blades. In one exemplary embodiment, the blades may turn in two directions.

Abstract: An apparatus and a method for operating a wind turbine capable of preventing the occurrence of damage of the blades by evading excessive irregular loads from acting on the blades in the slanting direction in the event of power failure when strong wind blows, are provided.

Abstract: A tidal power apparatus comprises a moored pontoon (1) having a duct (2) therethrough opening at opposed ends of the pontoon. The duct has a vertical axis rotor (3) therein driving an electrical generator (6). A deflector vane (8) is located in the duct at each end thereof, each deflector vane being mounted to pivot about a vertical axis between an active position, in which the deflector vane deflects water flow to one side of the rotor axis to cause rotation of the rotor, and an inactive position substantially aligned with the water flow from the turbine.

Abstract: A wind turbine blade instrumentation structure and method is provided for fluid dynamic polymer-based contact sensors measuring ambient pressure based on the resistivity changes across the sensor. The pressure sensors may applied in predetermined patterns to airfoil structures, such as wind turbine blades, without impacting the blade structure and fluid dynamic characteristics. The pressure sensors measure blade performance with high fidelity. The pressure measurements are transmitted to processing to determine blade characteristics and environment including flow separation, stagnation point, angle of attack, lift and drag and wind speed. Further processing of the pressure distribution may identify wind shear, up-flow and yaw error.

Abstract: A wind turbine energy conversion device that can take advantage of the higher speed and more persistent winds at higher altitudes is hereinafter disclosed. The wind turbine energy conversion device includes an unmanned aerial vehicle (UAV) connected to one end of a tether (which may include multiple shorter tethers), the other end being connected to a terrestrial anchorage point. The UAV flies at altitudes where wind speeds can reach 40 mph or higher. The UAV comprises a flying wing with one or more trailing wind power turbines and flies airborne maneuvers designed to increase relative wind speed up to about four times the true wind speed.

Abstract: A control system for mitigating the effects of a wind turbine on a radar system is disclosed. The control system includes a sensor configured to detect an operating condition of the radar system; a processor configured to receive an operating condition of the wind turbine and determine a rotation modification sequence based on the operating condition of the radar system and the operating condition of the wind turbine; and a controller configured to apply the rotation modification sequence to the wind turbine. A method of mitigating the effects of a wind turbine on a radar system is also disclosed.

Abstract: A fixed convergent collecting concentrator is provided. The concentrator contains two spaced-apart, co-axial, approximately horizontal, concentric plates with approximately circular shape centered on a vertical axis. The space between said plates is separated by vertical partition walls radially disposed about the axis thereof. The walls connect to the plates to form several sectors such that, irrespective of the direction of the wind, certain sectors collect and concentrate the air flow which enters the respective sectors. Each sector is connected to an intermediate tube which is in fluid communication with an accumulating tube, thus forming a system of tubes which is oriented in a common direction, optionally towards the ground. A turbine or other engine adapted for energy conversion being placed inside the concentrator or tubes.

Abstract: A wind driven turbine device is disclosed that includes a housing having an air inlet and an air outlet, a turbine rotor having a plurality of radially distributed turbine rotor blades mounted in the housing for rotation in direct response to atmospheric wind to thereby generate rotary power, a baffle arrangement is also provided for directing wind through the housing from the air inlet to contact the turbine rotor blades from behind as internal driving wind. The rotor is mounted in a manner such that the rotor blades are driven both by a combination of direct external wind and internally directed wind.

Abstract: A friction brake is provided for use in a wind energy system. The friction brake includes a piston adapted for being at least temporarily in contact with a braking surface, the piston having an outer circumferential surface that comprises a outer contact area. Further, the piston brake includes a housing for housing the piston, the housing having an inner surface that comprises a inner contact area wherein the inner contact area and the housing area are adapted for temporarily being in contact with each other. At least one of the inner contact area and the housing area is made of a non-metallic material. In addition, a wind energy system and a method for upgrading a wind energy system is provided.

Abstract: A vertical axis wind turbine includes an upstanding support structure, a plurality of generators disposed on the support structure, a central shaft in rotatable communication with the generators and positioned along a central axis of the vertical-axis wind turbine, a plurality of struts extending from the central shaft, and a plurality of blades, each blade positioned at an end of a corresponding strut and oriented substantially vertically. The vertical axis wind turbine optionally includes strut ailerons, blade extension elements, or blade ailerons to increase the efficiency and duty cycle of the wind turbine.