[Beowulf] cooling question: cfm per rack?

Dean Johnson dtj at uberh4x0r.org
Sat Feb 12 08:53:47 PST 2005

On Sat, 2005-02-12 at 09:49 -0500, Robert G. Brown wrote:
> Relative airflow can probably be measured with a kid's toy -- one of the
> little pinwheels -- and counting revolutions with a stopwatch.
> Normalizing that to absolute airflow in CFM is a bit tricky (since the
> result depends to some extent on the resistance imposed by the measuring
> apparatus) but somebody out there may have designed a version of this
> with a real fan and magnets set so that the counting is done
> electronically.  In fact, I could build something to do this out of OTC
> parts if I had any way to normalize the count.

Could you not use one of those cheapish wind speed devices that amateur
weather folks use? That would give you a rating, presumably in miles per
hour, and then figure backward based upon the area of the little fan
thingy. That would likely be not too expensive and a great deal easier,
and more accurate, to deal with than counting a pinwheel. ;-)


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