[Beowulf] cooling question: cfm per rack?

[Bill Rankin]

> Is cfm the key unit here or should one think in terms of pressure
> at various points in the room?

The other factor in heat removal (both within the rack as well as within
the air chiller) is the intake air temps.   The larger the temperature
difference the more efficient the heat transfer becomes.

Essentially, 50cfm of 20C air cools a lot better than 50cfm of 30C air. 
Also (as we are currently experiencing) the air handlers are much more
efficient at cooling really HOT air, versus warm air.

-bill


-- 
bill rankin, ph.d. ........ director, cluster and grid technology group
wrankin at ee.duke.edu .......................... center for computational
duke university ...................... science engineering and medicine
http://www.ee.duke.edu/~wrankin .............. http://www.csem.duke.edu