Half a croissant, on a plate, with a sign in front of it saying '50c'
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replace horiizontal-hubbed screws with vertical-hubbed extruded spirals
(+2, -2)
  [vote for,

A typical wind-power plant consists of many (even hundreds) of towers, each topped with a waht is essentially a classical windmill design: a horizontal axle points the mill so as to be perpendicular to the airflow. Another way of doing the same job, is as follows: Imagine three wheel-spokes joined at 120 degrees angle. Now extrude them so as to make a solid of 3-spoke cross-section. Next, imagine that the extuded shape is rotated on it's 'axle' as it extrudes - the result is like a barleycorn (if you know what I mean) or maybe somewhat resembling a DNA helix. Now, if you're still with me, this twisted extrusion is sculpted so as to fit inside a cone. Only about 270 degrees-of-twist of the extrusion are used in the cone. What we have now ought to resemble something you might get if you sanded the outside off a snailshell. This shape can be mounted vertically and be rotated by wind from any direction. I remember seeing similar shapes in old petrol-pumps with machanical metering of petrol flow, in a little translucent bubble stuck onto the delivery tube. The 'rotor', being of fairly compact shape, as opposed to the long-bladed windmill airscrews, can be made of any sturdy composite material, and therefore have a low radar-profile (air defences often object to wind-power). Whereas normal windmills use sophisticated gearing and blade-feathering to vary power delivered, this rotor can vary it's cross-section by lowering itself into a recess to reduce the power it takes. (in very stormy conditions, normal blades risk being destroyed unless they can carefully reduce thier profile to absolute minimum). These rotors would also need less altitude and would interfere less with birds and planes; They could also be built nmuch larger than windmills can today (eg. radii of 100m versus 25m).
nobodaddy, May 04 2002

(?) Vertical axis wind turbines http://aerolab.virtualave.net/wind/
[phoenix, May 04 2002, last modified Oct 21 2004]

(?) Historic Photos of Early Wind Machines http://www.cogreenp....org/PhotosHist.htm
[phoenix, May 04 2002, last modified Oct 21 2004]

(?) gorlov water turbine http://www.eeca.gov...Mar02/Renewable.htm
a double-helix [Laughs Last, Oct 04 2004, last modified Oct 21 2004]

helical wind turbine http://www.me.dal.c...ototype_Testing.htm
an extruded spiral [Laughs Last, Oct 04 2004, last modified Oct 21 2004]

(?) Quiet Revolution http://www.quietrevolution.co.uk/qr5.htm
Baked and on the market, almost exactly as you describe. However your idea precedes this as far as I know, so [+] [BunsenHoneydew, Jul 27 2006]


       The amount of energy that can be extracted from the wind depends pretty directly on how much wind the windmill (of whatever design) intercepts. For power-plant-scale production, that is why horizontal-axis windmills have dominated.
Vernon, May 04 2002

       Well, the horizontal arrangement has predominated but it's not clear to me that this is the most efficient way of gethering the wind energy.
A standard three-bladed windmill airscrew presents to the wind a surface area like: say roughly three degrees of arc per blade, total of 9 degress arc, which is 0.81% of the circle area.
Jet turbines have almost the complete area filled with blades, which is more efficient.
My 'rotor', OTOH, presents an area equal to the vertical profile, or in fact half of it, because one half is pushing into to wind as the other half is being pushed in the direction of the wind - a little less than half the profile taking into account that the rotation will vary the rotor blade angle..
nobodaddy, May 04 2002

       George Darrieus
bristolz, May 04 2002

       (As [bristolz] implies) Baked.
phoenix, May 04 2002

       This is a helical turbine, not a Darrieus turbine. Still mostly baked though. Try searching Google for helical wind turbine. This design is self starting (unlike Darrieus) and quiet (unlike bladed turbines) so it can be deployed unobtrusively in turbulent urban places as well as in wind farms. It looks like a great advance.
0ominous, May 05 2002

       So it might look like a big, spinning cone, or perhaps a pinwheel, correct? Why the cone-shape? Why not leave it as a cylinder?
RayfordSteele, May 05 2002

       nobodaddy, the early frontier-farm water-pumping windmills often had quite a fan of blades, like you describe in your annotation.   

       And, it seems to me that if you went to www.uspto.gov (the Patent Office website) and worked your way to Patent Number 6,036,443 you might find something similar to the helical design that your main idea is about.   

       Then there is Patent Number 4,424,002 which describes a vertical-axis machine that can intercept a significant amount of air, using SAILS. (Alas, I independently thought of the basic idea of this one, maybe even first, but couldn't afford to get a patent. On the other hand, I have yet another idea that may still be patentable...obviously any description of it here has to wait.)
Vernon, May 05 2002

       You don't need a rotor blade like a solid wall to make effective use of the wind. A smaller surface area which allows air to pass by the rotor maximises airflow through the turbine.
pottedstu, May 06 2002

       Why creating a 3 spoke cross section? DNA in itself is lending you the answer. a 3 spoke cross section is not needed all you really need for a self starting turbine is 2 spokes and a 180 degree turns. Manufacturing of this type of helix is extremely easy and cheap.   

       Why create a triangualr face? wouldn't a square face do? Ok, what about a curved face, resembling the shape of the lemon. That way you get rid of edges on the top and bottom and reduce turbulences that might lead to material stress and lower efficiency.   

       Think about the finish of the blades too... Ever thought why golf balls are covered with little holes? Because they help stabilize the ball in flight and make the hits up to 20% longer for the same power of stroke. Think about a similar arrangement of holes on the surface of this simple lemon shaped 2 spoke helical vertical turbine.   

       Not to mention the generator standing on the floor, eliminating the need for extra reinforcement of the structure and easier servicing...
toni, Jul 02 2002


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