Vertical axis windmill prices - Page 3

 

http://listserv.buffalo.edu/cgi-bin/wa?A2=ind9504&L=GEODESIC&T=0&F=&S=&Pg

  Anyone ever build one, at the apex of a dome? Neat idea by the way.
(I always thought a 2/3 buried geodesic sphere, would be the more
efficient design.)

http://www.ece.vill.edu/~nick/usenet/00001418

http://www.google.com/search?hl=en&q=Darrieus+rotor&btnG=Search

http://www.windturbine-analysis.netfirms.com/


http://windstuffnow.com/main/darrieus_type.htm

http://windstuffnow.com/main/vawt.htm

 A nice write-up to help us mortals deal with the numbers you
see in this thread.
http://windstuffnow.com/main/lenz2_turbine.htm

 The home page for this last site, don't know how I missed this
site, but it really strikes me as a great DIY site.  I wish more
were like this.
http://windstuffnow.com/main/

  A site with some perhaps useful info but it's harder to separate
the ego from the info.
http://energy.saving.nu/wind/winddesignprimer.shtml


Luck;
    Ken

 

"coriolus vertical windmill"

http://www.etfoundation.org/dcpc2005.html

http://thefraserdomain.typepad.com/energy/2005/11/new_vertical_ax.html

You can't do it with just one.  You would need a good number
all able to break into the prevailing winds.

Luck;
    Ken

 

A '2000 square foot grid connected home' doesn't really define how much
energy you think you need.  Are you in a climate that requires a lot of
A/C??  Does this include heating hot-water?  Too vague to really work with.

But if I *assume* that you're usage is 20 kWhr per day, that works out to an
*average* power of 833 Watts.  Then if I *assume* your windmill is 29.5%
effective at capturing wind energy and turning it into electricity (1/2 the
Betz Limit, no reason to believe it is anywhere near this good, but let's
just follow the bouncing ball and see where it takes us), you need a cross
section of about 15.5 m^2.  If it were a circular cross-section (such as a
Darious (sp?)) windmill, that's about 4.4 m diameter (15 ft).  Of course if
your system's performance is a lot lower in light winds, you may need to up
this quite a bit.

But be careful about 'average wind speed'.  Because power in wind varies
with the cube of velocity, you can't just use the simple 'average'
(arithmatic mean) of a bunch of wind speed readings and build your system
based on this 'average'.

For example:  If your 'average of 10 mph' came from exactly 12 hours a day
at 5 mph and exactly 12 hours a day at 15 mph, the 'average' would be 10
mph.  But for 12 hours at 5 mph your wind turbine would generate only 1.25
kWhr and for the other 12 hours at 15 mph you would generate 80 kWhr
(assuming your wind machine can scale up to 6664 Watts in a 15 mph wind).
If your generator and wind turbine are just rated for a bit over the
'average' power usage of 833 watts, say 1000 watts, then you would get just
12 kWhr for the 12 hours that the wind blows heavily, and only 1.25 for the
other 12 hours.  That's only a total of 13.5 kWhr when we started out
*assuming* your usage would be 20 kWhr per day.

daestrom