Re: FreeAxez raised flooring?

[William Herrin <bill () herrin us>]

On Fri, Mar 5, 2010 at 1:54 PM, Owen DeLong <owen () delong com> wrote:
> On Mar 6, 2010, at 2:41 AM, William Herrin wrote:
> > On Fri, Mar 5, 2010 at 12:54 PM, Owen DeLong <owen () delong com> wrote:
> > > Not sure about the purpose of a raised floor if it doesn't create a plenum, but, the
> > > step forward from raised-floor plenum is hot-aisle/cold-aisle which requires a good
> > > bit more discipline in your datacenter, but, is substantially more efficient.
> >
> > Hi Owen,
> >
> > Hot-aisle/cold-aisle is a separate issue from a raised floor plenum.
> > They're mutually supportive but not mutually dependent.
> I've never seen anyone do hot asile/cold aisle using raised floor.

Hi Owen,

Switch & Data in Vienna VA does it that way, as do parts of Equinix in
Ashburn VA. As often as not it's a retrofit where the raised floor was
already in place.

Even if you're not, though, the heat-density in the modern data center
is simply too high to prevent the warm air from the prior cabinet from
entering the top of the next cabinet unless you either generate a
minor hurricane through the floor or use a hot-aisle/cold-aisle design
so that nobody's breathing the other guy's warm air.


> Overhead cabling has become the norm in most modern installations
> and once you go to hot aisle/cold aisle, you no longer need the lower
> plenum, so, while they can be mutually supportive, neither requires
> the other, and, in practical modern usage, hot-aisle/cold-aisle usually
> precludes the need for the additional expense of raised floor.

The ductwork for hot aisle cold air can get in the way of access to
your wiring, especially in a large room. A raised floor obviates the
need for ductwork.

In general, though, I agree with you: if you don't already have raised
floor it isn't worth the additional expense, at least not in the data
center.


Regards,
Bill Herrin


-- 
William D. Herrin ................ herrin () dirtside com  bill () herrin us
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