WO 2008/017106 PCT/AU2007/001086 1 Omni-Directional Wind Power Station This invention relates to an omni-directional wind power station which utilizes critical arrangements of multiple units of a shrouded omni-directional vertical wind turbine 5 which discharges vertically and is capable of extracting higher quantities of electric power than a single "free wind" turbine of equal rotor diameter. BACKGROUND OF THE INVENTION 10 The exponentially rising global demand for electric power and the significant and entrenched damage caused to the ecosystem through the generation of such power utilizing non-renewable fuels such as oil and coal, together with 15 the rapid depletion of these resources and the lack of other natural resources to keep up with growing demand, has in the recent past provided new impetus to look towards the further development of renewable energy sources- Of these renewable resources, wind energy has 20 been the oldest and most utilized. Although, since the rotating electric generator was invented some attempts have been made to utilize wind power to drive generators, it is only in the last 50 25 years, with the discovery of strong and light weight materials; wind power has begun to be considered economically viable for this purpose. Wind turbines can be broadly divided into two groups. The 30 "horizontal" types, as in the very familiar Dutch windmill and the "vertical" types, as in the wind speed measuring cup/paddle or airfoil unit. Although, "vertical" wind machines are well known for their simplicity of design, WO 2008/017106 PCT/AU2007/001086 2 strength and fewer moving parts, due to the fact that they need not be constantly rotated to face the wind direction, their lower efficiencies in comparison to the horizontal type units have resulted in the horizontal type units 5 being favored. The commonly recognized theoretical analysis of wind power production indicates that, the power extractable from the wind is in proportion to the intercepted wind area and the 10 cube of the wind velocity. For wind turbines operating in free wind conditions, only by increasing the blade diameters to sweep larger areas can more power be extracted from the wind. This can now be seen in commercial power supply units having blade diameters in 15 excess of 150 meters. However due to their immense size requirements in low wind areas such as urban environments and the open rotating blades, they are not suitable for safe urban applications, which is where significant levels of power is used. 20 An alternative approach has been to utilize diffusers, shrouds or other devices to accelerate the free wind to increase its extractable energy density per square meter, prior to the wind. reaching the rotor blades. As the energy 25 extractable is proportional to the third power of the wind velocity, even minor accelerations can lead to significant increases in extractable power. This also enables the power extraction to commence at much lower wind velocities and be available for significantly longer periods during 30 the year. Consequently these could be utilized in areas where the wind velocity is lower than that useable by the free wind turbines.
WO 2008/017106 PCT/AU2007/001086 3 vertically discharging shrouds which accelerate wind and containing "horizontal axis" type wind turbines located in the vertical section have been attempted in the past in an effort to combine the best of both applications. One such 5 vertical turbine unit which I invented is described in the specification PCT/AU2005/001882 the specification and drawings of which are incorporated herein by cross reference. 10 It relies on the free wind approaching it being intercepted, accelerated and transported via concentric channels from the periphery of a shroud to be discharged to the full swept area of a wind driven rotor located with its axis vertical within the shroud. The rotor used is an 15 axial aerofoil type. it has the ability of utilizing low speed winds, regularly direction changing winds and turbulent winds which are prevalent in built-environments such as towns. 20 However due to its horizontally placed vertical axis rotor and the large shroud its not suitable for large capacity units (example greater than 10 kilowatts) in built environments. Thus its maximum power capacity is limited 25 in urban areas. It is best suited for individual large size use on top of high rise buildings. Although the rotor within it is protected by the shroud such that it can be used in public areas, its large foot print prevents its accommodation in pedestrian malls and 30 along street corridors in urban areas where wind flows from different directions. Arranging multiple units of individual vertical axis or horizontal axis wind turbines into vertical or horizontal WO 2008/017106 PCT/AU2007/001086 4. arrays in a stacked format in co-axial or non co-axial arrangements as well as connecting multiple wind turbine rotors via a common shaft, to form a collective larger power station have been attempted in the past to varying 5 degrees of success. The most commonly known type has been the horizontal axis turbine wind farm. The multiple stacked omni-directional Savonius rotors and Darrieus rotors and associated forms have also seen limited application. In all of these types of units wind enters 10 predominantly in the horizontal direction and exits predominantly in the horizontal direction However arranging multiple units of omni-directional shrouded vertical axis wind turbines where wind individually enters each turbine from a substantially 15 horizontal direction and individually exits each turbine in a substantially vertical direction has not been attempted. It is an object of the present invention to address or at least ameliorate some of the above disadvantages. 20 Notes 1. The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of". 25 2. The above' discussion of the prior art in the Background- of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.
WO 2008/017106 PCT/AU2007/001086 5 SUMMARY OF THE INVENTION In this specification the following definitions are used; The term "shroud" is used to denote the overall casing structure of- an individual omni-directional vertical wind 5 power turbine. That is, the shroud denotes the structure surrounding and defining the central collection chamber together with the structure defining the hollow member which directs air away from the central collection chamber after it has passed through the blades of the rotating 10 member. The rotating member itself is enclosed within this shroud structure. The term "vertical turbine" is used to denote an omni directional shrouded vertical axis wind turbine which comprises; 15 a) multiple curved members defining a central collection chamber substantially expanding in a direction of airflow there within; b) multiple vertical support members; 20 c) a hollow member which expands in cross section in the direction of air flow; d) a rotating member located above the central collection 25 chamber and connected to a generator to generate electricity from rotation of the rotating member; whereby the rotating member is located near an inlet of the hollow member of the individual omni-directional, 30 shrouded vertical wind turbine; WO 2008/017106 PCT/AU2007/001086 6 whereby each of the curved members is connected to at least one of the vertical support members so as to form air inlets into the central collection chamber; 5 whereby at least one of the curved members and the support members are shaped and spaced to direct air to a diametrically opposite side of an internal aspect of the, shrouded vertical wind turbine to form -an 'air gate' to reduce air leakage, from the shrouded vertical wind 10 turbine; whereby the curved members and the vertical support members are shaped and spaced to focus air directly to an entire lower surface of the rotating member. 15 whereby a majority of the wind enters the shroud in a "substantially horizontal" direction and a majority of the entering wind exits the shroud in a "substantially vertical" direction. 20 The term "substantially horizontal" is used to denote a zone of direction varying between 45 degrees above horizontal and 45 degrees below horizontal. 25 The term "substantially vertical" is used to denote a zone of direction varying between 0 degrees and 45 degrees to the vertical. Methods of critical placement of multiple omni-directional 30 shrouded vertical axis wind turbines which can result in successful formation of a wind power station and a wind farm has been developed and is disclosed in this specification.
7 Accordingly in one broad form of the invention there is provided an omni-directional wind power station comprising multiple vertical turbines arranged vertically adjacent to each other in an array for generating electricity. In a further broad form of the invention there is provided an omni-directional wind power station comprising multiple vertical turbines arranged horizontally adjacent to each other in an array for generating electricity. In a further broad form of the invention there is provided a method for forming an omni-directional wind power station for generating electricity, utilizing multiple units of a vertical axis wind turbine unit which is omni-directional, shrouded and discharges air substantially vertically, arranged adjacent to each other, comprising the steps of: using the vertical axis wind turbine units arranged vertically stacked co-axially or staggered non-coaxially; using the vertical axis wind turbine units arranged horizontally; using the vertical axis wind turbine units connected by a common shaft; using the vertical axis wind turbine units interconnected mechanically or electrically for the production of electrical power; using a plurality of inclined and vertical members to collect ambient airflow into a central collection chamber of each vertical axis wind turbine unit from any direction in a near horizontal plane; WO 2008/017106 PCT/AU2007/001086 8 using the inclined members to change the air flow direction from a near horizontal motion to a near vertical motion in each vertical unit; 5 using the inclined members and the vertical members to focus airflow from the windward side of a central collection chamber substantially directly across the full width of the chamber to a diametrically opposite side of a central collection chamber so as to substantially form an 10 air gate on the opposite and adjacent sides of the chamber to reduce air leakage from the opposite and adjacent sides of the central collection chamber in each vertical unit; using the inclined members and the vertical members to 15 direct the airflow to substantially all of the underside of a rotating member in each vertical unit; using a hollow member to permit the airflow leaving each of the rotating members to gradually return to atmospheric 20 pressure levels in each vertical unit; said turbines spaced from each other in said array so as to lie within a horizontal interaction zone and a vertical inter-action zone in said array whereby efficiency of each turbine in use is improved by a positive factor relative to a stand 25 alone free vertical turbine. Preferably said vertical interaction zone comprises turbines spaced vertically at greater than 0.3H. 30 Preferably said vertical interaction zone comprises turbines spaced vertically at less than 0.95H.
WO 2008/017106 PCT/AU2007/001086 9, Preferably a wind power station wherein the multiple units of the vertical turbines are arranged vertically adjacent to each other in an array with clear spacing, of between 30% to 95% of the overall height of the individual 5 vertical unit, between the extremities of each of the individual vertical turbine units. Preferably said horizontal interaction zone comprises turbines spaced horizontally at greater than 0.16W. 10 Preferably said horizontal interaction zone comprises turbines spaced horizontally at less than 0.76W. Preferably a wind power station wherein the multiple units 15 of the vertical turbines are arranged horizontally adjacent to each other in an array with clear spacing, of between 16% to 76% of the extreme width of the individual vertical turbine unit, between the extremities of each of the individual vertical turbine units, when taken at any 20 common horizontal plane between the two units. Preferably a wind power station wherein the multiple units of the vertical turbines are stacked vertically and staggered non co-axially, with a clear vertical spacing, 25 between each of the individual vertical turbine units. Preferably a wind power station wherein any of the individual vertical turbines in the vertical or horizontal array are installed rotated 180 degrees about a horizontal 30 axis, with the air discharge outlet having clear openings, in the vertical direction. Preferably a wind power station wherein the clear opening, in the vertical direction between the air discharge outlet and any other surface is not less than 85% of the diameter WO 2008/017106 PCT/AU2007/001086 10 of the swept area of the rotating member of the vertical turbine. Preferably a wind power station wherein the multiple units of the vertical turbines are stacked co-axially directly 5 one above the other with a clear spacing, between each of the individual vertical turbine units. Preferably a wind power station wherein a common central rotating shaft connects the rotating members of at least 10 two of the individual vertical turbine units to at least one electrical power generator. Preferably a wind power station wherein any or all of the individual vertical turbines are interconnected 15 mechanically or electrically to transfer any electrical power produced for utilization in any energy consuming equipment. Preferably a wind power station wherein the electrical power produced by the vertical turbines is stored in any 20 energy storage equipment for use in any energy consuming equipment. Preferably a wind power station wherein multiple wind power station units are grouped together to form a large wind power generating farm. 25 Preferably, the omni-directional, shrouded vertical wind turbine wherein the plurality of curved members includes non toroidal vertically curved blades connected to each other in a closed polygon arrangement.
WO 2008/017106 PCT/AU2007/001086 11 DRAWINGS The best contemplated constructional arrangements are illustrated in the accompanying drawings: 5 FIG. 1 Vertical Section view showing an embodiment of an individual vertical turbine FIG. 2 An embodiment of an individual vertical turbine mounted inverted (rotated 180 degrees about a 10 horizontal axis) on a tower structure FIG. 3 Omni-Directional Wind Power Station Type I Isometric view of an embodiment of multiple units of vertical turbines mounted vertically coaxially 15 (A) or staggered (B),to form a "vertical" wind power station FIG. 4 Omni-Directional Wind Power Station Type II Isometric view of an embodiment of multiple units 20 of vertical turbines mounted stacked vertically, with a common interconnecting power shaft FIG. 5 Omni-Directional Wind Power Station Type III Vertical turbines mounted arranged in a horizontal 25 line at the same height (A) or staggered in height (B), one next to the other, to form a "horizontal" wind power station. FIG. 6 Orni-Directional Wind Power Station Type TV 30 Vertical turbines mounted arranged inverted one next to the other. FIG. 7 Isometric view of an embodiment of an individual omni-directional shrouded vertical wind turbine WO 2008/017106 PCT/AU2007/001086 12 FIG. 8 An application of Wind Power Station- Multiple units of Vertical Wind power Stations grouped together to form a large wind power farm 5 FIG. 9 An application of Wind Power Station - Street light power poles (with or without energy storage) FIG. 10 An application of Wind Power Station - Large 10 Display Board (with or without energy storage) FIG. 11 An application of Wind Power Station - Single or multi-storey building edge mounting (with or without energy storage) 15 FIG. 12 An application of Wind Power Station - Single or multi-storey building Flat roof mounting (with or without energy storage) 20 FIG. 13 An application of Wind Power Station - Single or multi-storey building sloped roof mounting (with or without energy storage) FIG. 14A A Graph of expected efficiency behaviour as a function of horizontal turbine spacing relative to 25 stand-alone free vertical turbine efficiency FIG. 14B A Graph of expected efficiency behaviour as a function of vertical turbine spacing relative to stand-alone free vertical turbine efficiency 30 DETAILED DESCRIPTION OF THE INVENTION WO 2008/017106 PCT/AU2007/001086 13 Following is a description of an individual Omni Directional, shrouded vertical axis wind turbine (vertical turbine) utilized for the Wind Power Station: Figure 1 shows an embodiment of an individual vertical 5 turbine assembly 1 which is mounted with its base 2 rigidly connected to a support column 17. The turbine rotor 3 of rotor swept area diameter 'D', with air foil rotor blades, is attached via a central rotating shaft 16 to power generating equipment within the non 10 rotating hub 4 which is supported by a column 5 extending from the base 2 of the complete assembly. The rotor 3 is a horizontal exis type rotor mounted with its axis vertical. The hub contains the electrical power generator 15a and 15 all associated equipment for converting the rotor's rotational torque into electrical power. Vertical walls 6 arranged radially, extend in an angle to the vertical from the base 2 of the shroud to the bell mouth entry of the shroud. Radially they span from, near 20 the central air chamber's perimeter 12 to beyond the As best seen in Figure 1, multiple toroid blades 10a, 10b, 10c, 10d and 10e placed between the base 2 and the bell mouth of the shroud as shown in Fig 1 are secured between the vertical walls 6. 25 A conical section 37 extends from the last toroid's trailing edge 49 to meet the support column 5, to. completely enclose the last toroid's annulus. Referring to FIG. 1, wind flowing from any direction and entering the shroud's horizontal passage ways 13a, 13b 30 13c, 13d and 13e created by the toroid blades 10a, 10b, WO 2008/017106 PCT/AU2007/001086 14 10c, 10d and 10e, will accelerate and exit the blades at a higher velocity into the central collection chamber 12. The lowest passage 13e which is located closest to the central axis of the chamber is designed to produce the 5 highest exit velocity and it will be directed across the face of the inactive passage ways 38 which are not directly facing the wind. This movement of air acts as a fluid dynamic 'air gate', due to its pressure being lower than the pressure in the entry side 39 of the inactive 10 passage ways and induces air flow into the chamber 12 via the inactive passage ways, thus significantly reducing the escape of air entering the chamber via the active passage ways. As shown in Fig.1, the 'bell mouth' entry section toroid 7 15 of the shroud narrows concentrically towards the throat 8. The turbine rotor 3 is situated near down stream of the throat. The air stream profile of the rotor hub 4 and nose cone is designed to ensure that the air approaching the throat 20 from the active passage ways is able to flow across to the far side of the throat with minimal interference. This results in the full swept area of the rotor blades receiving air at near uniform velocities across it. The shroud then expands as the concentric. diffuser 9 with 25 an open top 21. This diffuser allows the pressure of the air leaving the turbine blades, which is below atmospheric pressure to rise steadily to near ambient pressure levels. The velocity of the air decreases as the diffuser expands. The diffuser extends and expands further as a collar 40 30 finally opening to the atmosphere 21. A wedge 41 is formed along the perimeter of the outer surface of the diffuser to deflect, in combination with the collar, near WO 2008/017106 PCT/AU2007/001086 15 vertically the free stream air approaching the diffuser from the wind ward side. This deflection creates a suction effect along the internal walls of the wind ward side of the diffuser and increases air flow exiting the diffuser, 5 resulting in increased air flow being drawn through the throat 8. Following is a description of various embodiments of the Wind Power Station: Fig. 2 shows an embodiment of the present invention. 10 forming the wind power station with an individual omni directional shrouded vertical wind turbine installed rotated 180 degrees about a horizontal axis (completely inverted) with a suitable support structure, such that the air discharge from the outlet of the unit is vertically 15 downwards. The clear opening height 'C', in the vertical direction between the air discharge outlet and any other surface is not less than 95% of the diameter 'D' of the swept area of the rotating member of the vertical turbine. This minimizes the resistance for the air exiting the 20 turbine after passing through the rotor. Depending on terrain and the type of obstruction this minimum spacing value 'C' will need to be higher. When the air discharge outlets of two vertical turbines face each other 'C' shall be a minimum of 225% as otherwise the discharge air from 25 both units will interact and reduce efficiencies. Fig. 3 shows embodiments of the present invention adapted for use as an omni-directional "vertical" wind power generating station which consists of multiple vertical turbines arranged vertically one above the other on a 30 structural support co-axially (A) or staggered off-axis (B), with open spacing 'T' between each of the individual vertical turbine units. This enables the velocity of the ambient wind approaching the open spacing to accelerate as WO 2008/017106 PCT/AU2007/001086 16 it passes through the spacing while still permitting air discharge into the spacing from the adjoining unit's discharge outlet. It also enables higher quantities of ambient air to enter the individual omni-directional 5 turbine unit that is located immediately adjacent to the opening. The height 'T' of the spacing shall be minimum 30%, preferably between 30% and 95% of the overall height 'H' of an individual vertical turbine unit. This "vertical" 10 power station configuration results in increased power generation due to the increased air flow through the individual vertical turbine unit's rotor, as a result of the increased suction across the face of the discharge out let of each individual unit in a vertical interaction 15 zone. The vertical interaction zone is a zone of vertical spacing between adjacent vertical turbines which is selected so that the efficiency of the turbines is greater than the efficiency of a stand-alone free vertical turbine. In preferred forms the vertical interaction zone 20 excludes vertical turbines spaced at less than 30% spacing. At less than 30% vertical spacing the air flow through individual units is throttled and power generation reduced. In preferred forms the vertical interaction zone excludes vertical turbines spaced at greater than 95% 25 spacing. At greater than 95% vertical spacing the power enhancement effect due to acceleration of ambient air flow through the spacing is lost. Fig.4 shows an embodiment of the present invention adapted for use in an omni-directional "vertical".wind power 30 generating station which consists of multiple vertical turbines arranged vertically stacked, one directly above the other, with a common central rotating shaft connecting WO 2008/017106 PCT/AU2007/001086 17 the turbine rotors of two or more of the units to one or more electrical power generators. This permits the use of multiple larger sized or a single 5 very large sized generator for the wind power station and reduces the complexity of integrating the electrical power generated by multiple units. This also increases the efficiency of the electrical power generator through reduced machine losses. 10 Fig. 5 shows embodiments of the present invention adapted for use in a "horizontal" omni-directional wind power generating station which consists of multiple vertical turbines arranged in a horizontal line, one next to the 15 other at the same height (A) or staggered in height (B) with spacing between each of the individual vertical turbines. The spacing 'G' between the extremities of each of the vertical turbines shall be a minimum of 16%, preferably between 16% and 76% of the extreme width 'W' of 20 an individual vertical turbine unit, when taken at any common horizontal plane between the two units. This "horizontal" power station configuration results in increased power generation due to the increased air flow 25 through the individual vertical turbine unit's rotor, due to reduced by passing of air around individual units in a horizontal interaction zone, The horizontal interaction zone is a zone of horizontal spacing between adjacent vertical turbines which is selected so that the efficiency 30 of the turbines is greater than the efficiency of a stand alone free vertical turbine. The preferred horizontal interaction zone excludes vertical turbines spaced at less than 16% spacing. Below this spacing the total air approaching the complete power station is reduced, WO 2008/017106 PCT/AU2007/001086 18 resulting in power loss. The preferred horizontal interaction zone excludes vertical turbines spaced at greater than 76% spacing. At greater than this spacing the power enhancement effect due to interaction of air 5 flow by-passing the units is reduced progressively and lost. In all of the embodiments of the present invention described above, any or all of the individual vertical 10 turbines may be arranged in the normal (up right) configuration or in the 180 degree rotated (inverted) configuration as shown in Fig.6. Any of the embodiments of the present invention described 15 herein or shown in the Figures 2 - 13 can consist of any number of vertical turbines in their arrangement. Surfaces of any slender support structures.or the rotating shaft and its enclosure between any vertical turbine units 20 are to be ignored for the spacing requirements in all of the above embodiments of the invention. Description 25 With reference to the above detailed description, salient features of the above described embodiments are summarized below: There is provided an omni-directional wind power station 30 which is formed by arranging multiple units of shrouded vertical discharge omni-directional wind turbines, in a vertical or horizontal or mixed arrangement adjacent to each other. Each of the individual omni-directional, shrouded vertical discharge wind turbines utilized 35 consists of an axial, aerofoil type rotor placed within a WO 2008/017106 PCT/AU2007/001086 19 shroud. The open design of the shroud with minimal constriction in comparison with other vertical discharge shroud arrangements, the aerodynamic focusing, accelerating arrangements, the fluid dynamic "air gate" 5 arrangement to prevent leakage and the wedge/collar arrangement at the discharge of the diffuser to increase suction effects through the shroud promotes much higher air volumes to flow through the rotor. The power extracted by the rotor is transferred to an electric power generator 10 through a rotating.shaft mechanism. The critical placement of the units in a specific arrangement related to their location with respect to each other, leads to additional enhancement of air flow through 15 the individual turbine units producing higher levels of power than that possible in a random arrangement of multiple units. The slender profile of an embodiment of the vertical wind 20 power station allows accommodation of it in single or multiple numbers in either open areas in the country side or in narrower street ways within suburban areas. Material 25 The choice of materials for the individual omni directional, shrouded vertical wind turbine's vertical walls, diffuser and toroidal blades will be among strong, light weight metals, composites, sandwich construction 30 etc. The rotor blade materials will involve a combination of light and strong materials that are present state of the art in the industry, to minimize start-up inertia of the rotor and enhance the response to light winds.
WO 2008/017106 PCT/AU2007/001086 20 The structural framework for forming the wind power station, utilizing the multiple individual units, can be of any common building structural materials including steel, aluminium, concrete or other metal and non-metals 5 as well as composites. IN USE In use the embodiments of the present invention are 10 adapted for use in a variety of terrains. Some embodiments can be used in remote areas and in urban areas. The shrouded nature of embodiments reduces the chance of persons or objects from being injured in the event that parts of the turbine become detached during use. 15 Additionally, the shroud form minimizes low frequency noise by acting as a barrier to buffer noise produced by moving components of the wind turbine. Further, shrouding also reduces visual problems associated with stroboscopic 20 light reflection from rotating parts of the turbine. Further, the non-requirement of a yawing mechanism to turn individual rotors to face the prevailing wind direction has eliminated all gyroscopic forces on the rotors, 25 bearings and associated mechanisms negating a major source of common failure of wind turbines. In a further broad form of use similar to shown in figure 8 the embodiments of the present invention are adapted for 30 use in multiple numbers grouped together, located in a common geographical area to form a large wind power generating farm.
WO 2008/017106 PCT/AU2007/001086 21 In a further broad form of use similar to shown in figure 9 the embodiments of the present invention are adapted for use in street light power poles, with or without energy storing devices 20, to provide power to the lamp. 5 In a further broad form of use similar to shown in figure 10 the embodiments of the present invention are adapted for use atop and aside bill (display) boards, with or without energy storing devices 20, to provide power. 10 In a further broad form of use similar to shown in figure 11 the embodiments of the present invention are adapted for use along the roof or building edge of single or multi-storey buildings, to provide power to the building. 15 In a further broad form of use similar to shown in figure 12 the embodiments of the present invention are adapted for use atop a single or multi-storey building with a flat roof, raised above the flat roof on a platform located 20 away from the edge of the building, to provide power to the building. In a further broad form of use similar to- shown in figure 13 the embodiments of the present invention are adapted 25 for use along the roof ridge of a building with sloping roof profile, to provide power to the building. In a further broad form of use the embodiments of the present invention are adapted for use as an energy 30 supplying device for a energy storage devices for use in a caravan, boat or other vehicle. Benefits WO 2008/017106 PCT/AU2007/001086 22 Embodiments of the present wind power station invention can have one or more of the following advantages over standard art vertical turbines and horizontal turbines; 5 a. The wind power station can be placed in malls and along streets and in suburban areas without any fear of large moving components breaking and impacting on any surrounding structures or persons, as the moving rotor blades are contained in shrouds 10 b. Generation of rotor blade tip vortices, which are a major source of noise from free wind turbines in use in urban areas, are significantly reduced as the blade tips are contained in shrouds. 15 c. It is capable of being utilized in lower wind speed areas, as the shroud accelerates the wind and increases power extractability. This allows the production of useful power for longer periods. 20 d. The capability of utilizing wind of lower speed coming from rapidly changing directions, without the need for constant adjustment of the complete assembly to face the wind, allows the invention to be placed in suburban 25 centers or other population centers nearer to the end consumer of the electric power. e. The formation of the "vertical" wind power station enables increased electrical power generating capacities 30 to be achieved, in desired incremental steps, for the same width of ground and air space. f. These "vertical" wind power stations result in small foot prints for the complete assembly and permits WO 2008/017106 PCT/AU2007/001086 23 installation of the power stations in narrow corridors between building structures or/and other such terrain where wind velocities are significantly increased. 5 g. The formation of "horizontal" wind power stations permits installation of this assembly along roof ridges, building edges. h. The modular construction allows great ease in 10 fabrication, transportation and installation of the units. i. The failure of any individual omni-directional, shrouded vertical wind turbine unit during operation results in only a partial loss of power and not in the 15 total loss of power as conventional large capacity single wind turbine units. The description of embodiments of the present invention has been made with reference to specifically preferred 20 features. However various optimizing enhancements can be made without departing from the principles of the disclosed inventive subject matter particularly pointed out above and claimed here below 25 As a general statement: There is provided a wind power station comprising an array of individual omni directional, vertical discharge wind turbines, arranged critically spaced in various configurations to generate electrical power. Each of the 30 individual omni directional wind turbines consists of a shroud that captures wind from any direction and directs it to flow vertically through a throat section where an aerofoil multi-bladed rotor is connected to an electrical power generator via a rotating shaft. The intake of the.
WO 2008/017106 PCT/AU2007/001086 24 shroud incorporates multiple horizontally curved blades secured in place by multiple vertical walls such that while accelerating and focusing the wind, .across the full swept area of the rotor blades, the loss of air from the 5 central collection chamber is significantly reduced by the air flow forming a fluid dynamic gate across inactive faces. The critically arranged configurations generate higher levels of power than a random arrangement of vertica-l turbine units. 10