CA2306491A1 - Multiple-sail wind energy concentrator - Google Patents

Abstract

The proposed apparatus is a means for concentrating wind energy in view of generating electricity, with such a means being capable of converting winds of moderate speed. The apparatus is meant for wind farm applications, where relatively large installations are set up in fields, on hills or on ridges. The proposed apparatus features multiple funnel-shaped sails that concentrate natural wind into airstreams whose velocities are of a higher order of magnitude. These individual airstreams are collected through a conduit that feeds a single, relatively massive, high-velocity airstream into a turbine and through a box-shaped, sound-insulated terminus. Thus, the proposed apparatus is a means for having a series of wind capturing devices produce one large high-speed flow of air suitable for power generation.

Description

Title: MULTIPLE-SAIL WIND ENERGY CONCENTRATOR
The pro sed apparatus is a means for concentrating wind energy in view of gen sting electricity, with such a means being capable of converting win of moderate speed. The apparatus is meant for wind farm applications, ere relatively large installations are set up in fields, on hills or on rl es. The proposed apparatus features multiple funnel-shaped sails that co ntrate natural wind into airstreams whose velocities are of a higher order magnitude. These individual airstreams are collected through a duit that feeds a single, relatively massive, high-velocity airstream into a rbine and through a box-shaped, sound-insulated terminus. Thus, proposed apparatus is a means for having a series of wind capturing 'ces produce one large high-speed flow of air suitable for power generati Snecificati~
1. General Character of the Inventive Idea This invention relates to means for converting wind energy into electricity. The idea is an apparatus capable of concentrating wind, especially that of moderate speed, into a relatively massive, high velocity airstream that lends itself to efficient power generation.

2. Nature of the A~naratuses Previousl3r Known Wind energy extraction devices are typically blade-type airfoils rotating on a horizontal axis, or "Darrius" or "Savonius" type airfoils rotating on a vertical axis, or again devices having "drag-type" aerodynamics, rotating on an axis of either kind. Variances to these types of apparatuses exist, yet a common trait is that the wind capturing devices themselves, as mobile parts, constitute turbines. When multiple turbine units are installed side by side, as in the case of a wind farm, multiple generators are required as each turbine is coupled to an individual generator. What would be uncommon is a means for having multiple wind capturing devices feed a single turbine and generator set.

Sails, as capturing devices, are known to be integrated into both horizontal and vertical axis types of turbines, and may be used for some types of wind concentrators.
A number of concentrators make use of a funnel-shaped wind intake device of one kind or another. In each case such a device channels wind into a turbine, whose axis is either horizontal or vertical. Another type of wind energy concentrator, called a diffuser, is a shroud fitting around a turbine so as to create a low pressure zone leeward from the turbine. A further type of concentrator is a wing-like structure extending windward from two horizontal axis turbines. All these concentrators may feed into a turbine an airstream of increased speed compared to that of natural wind. Yet it would be uncommon for a concentrator to produce a relatively massive airstream of higher velocity.
Altogether, wind energy conversion devices are limited in their capacity to generate electricity cost-effectively from moderate-speed winds.
Currently, the economic viability of large scale wind power plants is limited to geographic areas where average wind speeds are superior to fifteen kilometres per hour. Yet there are vast areas in the world where comparably moderate wind regimes would constitute potential sources of electrical energy if a viable means for converting such moderate winds was available.

3. How the Inventive Idea Overcomes Limitations of eviously Known Practices or Pr sals The proposed apparatus is a means for having multiple funnel-shaped sails concentrate natural winds, especially winds of moderate speed, into airstreams whose velocities are of a higher order of magnitude.
These individual airstreams are collected through a conduit that feeds one relatively massive airstream into a turbine.
Thus, the proposed apparatus is a means for having multiple wind capturing devices produce a single, massive, high-velocity airstream that lends itself to efficient power generation.
Overall, the proposed apparatus may be a viable means for generating electricity in areas of moderate-speed winds, thus overcoming a difficulty related to previous practices or proposals.

4. Full Description In drawings which illustrate embodiments of the invention, Figure 1 is a downward vertical view of an apparatus. Figure 2 is a perspective view of a sail funnel including its support structure and accessories, along with a conduit segment. Figure 3 is a perspective view of a terminus along with a conduit segment.
Figure 1 shows ten sail funnels 1 along with their respective tower tops 2 and awnings 3, a set of conduit segments 4 and the covers 5 of a terminus. An arrow 6 shows the wind direction and accordingly, the vertex 7 of each sail funnel 1 is maintained in leeward position by virtue of the funnel shape having the effect of a wind vane.
Immediately downstream from any point where a sail funnel 1 is connected to a conduit segment 4, the transversal area of the conduit segment 4 may increase proportionately to the transversal area of the airstream being channeled between the sail funnel 1 and the conduit segment 4, in order to help equalize air pressure throughout all conduit segments 4.
For the same purpose, immediately downstream from a confluence 8, the transversal area of the conduit segment 4 may increase proportionately to the sum of the transversal areas upstream of the confluence 8.
A turbine 9 is located where the airstream collected from all conduit segments 4 enters into the terminus. A generator is coupled to the turbine 9.
Conduit segments 4 may be made of a pliable material such as heavy-duty sailcloth, or of a rigid material such as fiberglass. In order to anchor a sailcloth conduit to the ground and in order to protect this sailcloth from rubbing on rough terrain, the conduit may be fastened onto old rubber tires laid down and tied together so as to form a cushion.
In the embodiment shown in Figure 2, the pivoting axis may consist of two overlapping sections: a round post 10 section at the bottom and a lattice tower 11 extending upwards. The round post 10 section pivots on the bottom of a cylinder 12, which is cast in concrete into the ground. A hinge 13 may provide a means for raising and lowering the longest part of the lattice tower 11 without the use of a crane.
The lower boom 14 and the upper boom 15 may be made of latticework, or of tubular or other materials.
The sail funnel 1 is rectangular-shaped along its upstream edge. In order to attach the lateral edges of the sail material to the sail holding cables 16, a series of clip-on hooks may be used. These hooks may slide easily on a holding cable 16 when pulled either up or down.
Downstream towards the vertex 7, the form of the sail funnel 1 changes progressively from rectangular to round. This vertex 7 is a rounded bend leading to the upper channel 17, and these parts may both be made with heavy-duty sailcloth.
The wind intake area is subject to being fully opened, fully closed, or set anywhere in between, so as to control the amounts of wind and precipitation entering the sail funnel 1. Adjustments may be done by hoisting or lowering the sail's base along the sail holding cables 16, using a tackle 18 operated from the control station 19. While this tackle 18 may be operated by hand by a person standing either on the ground or on the flat passage 20, it may also be activated remotely using a radio-controlled electric motor. A further possibility is to automate the upward or downward movement of the sail's base by using an electric motor responding to data provided by an anemometer.
The vertex 7 may be located in line with the upper half of the rectangle formed by the upstream edge of the sail, thus giving the sail funnel 1 an asymetrical shape. When the intake area of sail funnel 1 is partially closed, this asymetrical shape would help reduce turbulence as the wind flows into the vertex 7. This asymetrical shape would also be accomodating when the intake area of sail funnel 1 is fully open, given that wind speed tends to increase with height above the ground.
A bird screen 21 may be installed and its mesh should be small enough to keep birds from entering the sail funnel 1. The lateral edges of the bird screen 21 may be attached to the sail holding cables 16 using a series of clip-on hooks interspersed with the hooks used for the sail. As an option, the bird screen 21 may be attached to an additional set of cables running alongside the sail holding cables 16.
An awning 3 serving to limit the precipitation entering into the sail funnel 1 extends on the windward side of the upper boom 15. The awning 3 may slope downwards in the windward direction as well as in each lateral direction. The cover of the awning 3 may be made with pliable material and may be attached with springs to the awning support structure 22, so that the wind's action exerts a "trampoline" effect on overlying snow or ice. The support structure 22 may be made of tubular or other rigid materials, and may include cables.
Downstream from the vertex 7, the upper channel 17 extends to the mobile joint 23 to which it is attached. The mobile joint 23 is solidly attached to the post 10 so as to pivot along with the latter. The contact between the mobile joint 23 and the fixed joint 24 should be tight, so as to minimize air seepage. Both the mobile joint 23 and the fixed joint 24 should be made of rigid materials. In the case of both the mobile joint 23 and the fixed joint 24, the passageway transversal areas - the total transversal areas minus the transversal area occupied by the post 10 - should be at least as large as the transversal area of the upper channel 17, so as to avoid creating a bottleneck. The form of the fixed joint 24 changes from cylindrical to rectangular and relatively wide, in order for the fixed joint 24 to be attached to the flat passage 20.
The transversal area of the rectangular-shaped flat passage 20 should be at least as large as that of the upper channel 17, so as to avoid creating a bottleneck. The flat passage 20 serves to give an operator access to the control station 19 when the latter moves over this part of the airstream enclosure. In order to allow a few persons to stand on the flat passage 20, the latter should be built with rigid materials. A guardrail 25 serves to protect operators from falling on the lower channel 26, which may be made of heavy-duty sailcloth.
The shape of the lower channel 26 changes from rectangular to cylindrical, in order to connect the flat passage 20 to the conduit segment 4. The orientation of the lower channel 26 relative to the conduit segment 4 is that of an optimum angle for minimizing resistance as the airstream flows out of the lower channel 26 and into the conduit segment 4.
In the embodiment shown in Figure 3, the walls 27 and covers 5 of the terminus are designed to muffle the noise made by the turbine 9 and to redirect the airstream upwards. The shape of the terminus may be that of a rectangular box having a modified top as well as an inlet and an outlet for the passing airstream. The walls 27 may be made of a high fence on which is fastened lightweight sound insulating material as well as a membrane resistant to breaking airstreams. The support posts 28 for such a high fence may be steadied with the use of guy wires 29 fixed to the ground. The covers S may be constructed with materials similar to those of the sides, but lighter. The covers 5 should be designed to accomodate precipitation and other local climatic factors e.g. non-accumulation of snow and ice may require a relatively steep slope.

5. Othe~Wa3rs in Which the Inventive Idea Mav Be Used The airstreams originating from a relatively large number of sail funnels 1 may be chanelled to a single turbine 9 through numerous confluences $ of conduit segments 4, so as to accomodate factors such as topography., land use and power plant economics.
A stripped and smaller scale apparatus may make use of a single pivoting sail funnel 1 feeding an airstream into a turbine 9. This stripped version may or may not include a sound-muffling terminus.

Claims (3)

1. A wind energy concentration apparatus comprising multiple pivoting sail funnels 1 that convert natural wind into higher velocity airstreams, and featuring multiple conduit segments 4 that collect these airstreams to constitute one relatively large high-speed flow of air that is fed into a turbine 9 and through a box-shaped, sound-insulated terminus.

2. A sail funnel 1 pivoting on a vertical axis and featuring: a wind intake area that can be expanded or reduced by hoisting or lowering the base of the sail along the sail holding cables 16; a vertex 7 located in line with the upper half of the rectangle formed by the windward edge of the sail, so as to optimize airflow into the vertex 7 whether the wind intake area is fully open or partly closed; an awning 3 serving to limit the entry of precipitation; a screen 21 blocking the passage of birds; an airstream enclosure comprising a mobile joint 23 pivoting over a fixed joint 24 as well as a flat passage 20 on which people can walk in order to have access to the control station 19 when the latter moves over this flat passage 20.

3. A conduit through which the airstreams originating from individual sail funnels 1 are collected, featuring multiple conduit segments 4 and possibly multiple confluences 8, with the transversal area of each conduit segment 4, immediately downstream from any point where a sail funnel 1 is connected, increasing proportionately to the transversal area of the airstream being channeled from the sail funnel 1, and with the transversal area of a conduit segment 4 located immediately downstream from a confluence 8 increasing proportionately to the sum of the transversal areas of the conduit segments 4 found immediately upstream of that confluence 8.