Air-X & noise levels [RE-wrenches]

[David Blittersdorf]

Ian and Chris,

Swept area is the best rough comparison and capacity factor is also useful. I still would 
like to see a common rated windspeed that is around 11 m/s (24.6 mph) with the 
capacity factor calculated with the 11 m/s rated power point. 

The other problem is that many supplied power curves are not very accurate and are 
very optimistic. 

David Blittersdorf


On 5 Mar 2002 at 9:12, Ian Woofenden, Home Power wrote:
> 
> Hi David,
> 
> >I agree with Ian that the $/rated watt is misleading as a number of 
> >turbines have a very
> >high rated wind speed. The 10kw Bergey Excel (a rugged, heavy 
> >turbine) is rated 10kw
> >at 31 mph. A  more realistic rated windspeed is 24 mph and would 
> >give the 10kw a 6kw
> >rating.
> >
> >I suggest when comparing turbines to use a common rated windspeed 
> >(say 24 mph or
> >11 m/s). Also compare weight to the new rated wind speed.
> >
> >Regards,
> >
> >David Blittersdorf
> 
> I think it's not as simple as this, but I'd like your comments on my 
> theory and experience. I'm running an older Whisper 1000 and the AWP 
> machine in similar windspace. The Whisper's peak output (and rating) 
> is 1,000 watts. The AWP's peak output is 900 watts. The AWP's 
> published power curve shows that it peaks at about 12 m/s (27 mph). I 
> don't have a power curve for the Whisper, but Mick Sagrillo's HP65 
> chart shows that it is rated at 25 mph and governs at 27 mph.
> 
> The swept area of the AWP is almost twice that of the Whisper, and 
> the KWH output is just over twice (2.15 to 2.29 X for January and 
> February 2002). If I compare by peak watts, the Whisper looks better. 
> If I compare by watt-hours, the AWP is twice the machine.
> 
> Do you think that rating these two turbines at 24 mph would give a 
> more accurate comparison? I'm inclined to rely on swept area for 
> comparisons between machines. It oversimplifies things a little, but 
> seems nowhere near as inaccurate as relying on peak output.
> 
> Ian
> 
> 
> 
> 
> >
> >On 4 Mar 2002 at 16:26, Ian Woofenden, Home Power wrote:
> >
> >>  Hi Charlie,
> >>
> >>  >  >Proven
> >>  >
> >>  >Good and quiet machines www.provenenergy.com . I am in the middle of
> >>  >installing a system using a Proven 600W at the moment. As Chris 
> >>says, they are
> >>  >not cheap relative to other makes - unless you do a comparison of cost per
> >>  >kilo!!
> >>
> >>  I've suggested to Mick Sagrillo that he delete the "$ per rated watt"
> >>  category in his wind generator comparison, and instead give us
> >>  categories for "$ per square foot of swept area" and "$ per pound".
> >>
> >>  I think either of these two comparisons mean more than comparing peak
> >>  output, and using both gives a fairly intelligent view of output and
> >>  reliability.
> >>
> >>  We'd love to see an article in HP on your Proven installation.
> >>
> >>  Ian
> >>
> >>
> >>  >Charlie
> >>  >
> >>  >Charlie Robb
> >  > >Element Engineering
> -- 
> Ian Woofenden <ian.woofenden at homepower.com>, Fax: 360-293-7034
> Associate Editor, Home Power magazine, The Hands-On Journal Of Home-Made Power
> Editors are Professional Idiots - We misunderstand text so our readers won't.
> 
> HP subscriptions: $22.50 per year, PO Box 520, Ashland, OR 97520 USA
> 800-707-6585 (US), 541-512-0220, or download current issue at 
> <http://www.homepower.com> 
> 
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> 

David Blittersdorf
NRG Systems, Inc.
110 Commerce Street
Hinesburg, VT 05461 USA
Tel: 802-482-2255
Fax: 802-482-2272
email: davidb at nrgsystems.com
Web:http://www.nrgsystems.com

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