Posted by William Wixon on February 16, 2008, 10:35 am
http://www.recordonline.com/apps/pbcs.dll/article?AID=/20080216/NEWS/802160316
Posted by Eeyore on February 16, 2008, 10:49 am
William Wixon wrote:
What about it ?
Posting links with no comment is silly.
Graham
Posted by Solar Flare on February 16, 2008, 1:40 pm
Look like an awful noisy design!
> http://www.recordonline.com/apps/pbcs.dll/article?AID=/20080216/NEWS/802160316
>
Posted by daestrom on February 16, 2008, 9:59 pm
> http://www.recordonline.com/apps/pbcs.dll/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 3.69e6 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 1.2 kg/m^3, that would require a constant windspeed of 12.8
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 3.69e6 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
Posted by William Wixon on February 17, 2008, 12:12 am
> 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 3.69e6 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 1.2 kg/m^3, that would require a constant
> windspeed of 12.8 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 3.69e6 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
thanks for reading the article and responding to my post.
b.w.
(i know, it does look kinda hokey huh? i was hoping though that somehow it
was going to work out ok for everyone involved.) (it's nice that a local
college is getting involved in such stuff and that Ikeda is footing the bill
for it.)
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