alt.energy.homepower

"William Wixon" wrote in message
news:$@...
> /apps//article?AID=/20080216/NEWS/802160316
>

Frankly, I'm skeptical of the design. It looks like it will just clear some
of the tree tops (lot of turbulent air at that level). Without a close look
at the padels I can't tell what the drag would be like on those padels as
they traverse back 'upwind'.

I don't see any information about the average wind speed at that location,
so it's impossible to tell what Ikeda's claims for this really mean. With
an aspect ratio of roughly 2:1, it looks like it might have a swept area of
about 6000 ft^2 (562 m^2).

To produce kW-hours per year, in a perfectly steady 24/7 wind, it
would have to average 421 kW output. If it were to operate at the
theoretical limit for any wind machine, that would mean 714 kW of wind power
flowing through those 562 m^2. That's about 1270 watts per m^2. With air
density of about kg/m^3, that would require a constant windspeed of
m/s all year long. If I got my sums right :-).

That's over 28 mph, 24/365 and I'm pretty sure it's not that windy there,
especially just above the tree tops. And I'm quite certain that this design
doesn't extract the theoretical maximum. Unless the reporter made a typo
and that's supposed to ready watt-hours, I don't believe it. (but
that would mean an average output of just 421 watts for such a large unit).

I'm glad the board at least put a proviso to review the performance after a
year of operation. I think they'll be very disappointed.

daestrom