Air-X & noise levels [RE-wrenches]

[Ian Woofenden, Home Power]

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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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