# Vertical axis windmill prices

Discussion in 'Home Power and Microgeneration' started by The Master, Jun 11, 2008.

1. ### The MasterGuest

Does anyone by chance have a price, or know of a place selling them that
actually tells you the price up front, for a vertical axis windmill large
enough to power a 2,000 square foot grid connected home in a 10 MPH
average wind?

I have been able to locate several makers of vertical axis windmills, but
I have been unable to locate any sort of a price quote. And I get enough
spam e-mail as it is, without having to sign up for more just to get a
price...

2. ### YouGuest

Did you try CALLING the OEM's, on the Phone, and asking them the price?

3. ### EeyoreGuest

10 mph is a pretty slow wind to get much power from and at *ground level* too
?

Graham

4. ### RW SalnickGuest

brought forth on stone tablets:
Interesting design. But multiply by two for required area - VAWTs only
use half the swept area (in fact, it is worse than that, since the

bob

5. ### Guest

An average US house uses about 800 kWh/mo, about 1100 watts on a continuous
basis, and page 36 of Paul Gipe's 1993 Wind Power book says the wind power
density with a Rayleigh speed distribution is 0.104V^3 W/m^2, where V is
the average windspeed in mph and the best rotors achieve 40% efficiency
(vs the 60% Betz limit)... 90% efficiencies for the transmission, generator,
and power conversion make the wind power density 0.0303V^3 W/m^2, or 30.3
W/m^2 at 10 mph, so you might have 1100/30.3 = 36 m^2 of swept area, eg
a 22 foot diameter circular windmill, comparable to the size of the house.

I don't know where to buy one of these, but you might make a high-speed,
6-blade double-delta Darrieus rotor with 2 tetrahedra joined on a horizontal
face, rotating on 2 points, with an automobile wheel at the top and another
at the bottom, attached to a 5:1 step-up auto rear with the spider gears
welded together, with more stepup for an induction motor that could act as
a motor to start the rotor.

It might have 6 galvanized steel tubes and 6 thin, low-solidity dacron
trailing edges attached to 6 wires. A tension ring with 3 horizontal wires
could connect 3 points halfway up to give the windmill vertical support,
and 3 guy wires could hold down a pillow hlock at the top.

Good luck

Nick

6. ### Guest

Not if they are fast.

Nick