Re: cooling door

jcurranmail.com (John Curran) writes:

> While the chilled water door will provide higher
equipment
> density per rack, it relies on water piping back to a
"Cooling
> Distribution Unit" (CDU) which is in the corner
sitting by your
> CRAC/CRAH units.

it just has to sit near the chilled water that moves the
heat to
the roof.  that usually means CRAC-adjacency but other
arrangements
are possible.

> I know that it would have to be quite a bit before
> many folks would: 1) introduce another cooling system
> (with all the necessary redundancy), and 2) put
pressurized
> water in the immediate vicinity of any computer
equipment.

the pressure differential between the pipe and atmospheric
isn't
that much.  nowhere near steam or hydraulic pressures.  if
it gave
me ~1500w/SF in a dense urban neighborhood i'd want to learn
more.
-- 
Paul Vixie

At 7:06 PM +0000 3/29/08, Paul Vixie wrote:
> > While the chilled water door will provide higher
equipment
>> density per rack, it relies on water piping back to
a "Cooling
>> Distribution Unit" (CDU) which is in the
corner sitting by your
>> CRAC/CRAH units.
>
>it just has to sit near the chilled water that moves the
heat to
>the roof.  that usually means CRAC-adjacency but other
arrangements
>are possible.

When one of the many CRAC units decides to fail in an
air-cooled
environment, another one starts up and everything is fine.  
The
nominal worse case leaves the failed CRAC unit as a
potential air
pressure leakage source for the raised-floor and/or
ductwork, but
that's about it.

Chilled water to the rack implies multiple CDU's with a
colorful
hose and valve system within the computer room (effectively
a
miniature version of the facility chilled water loop). 
Trying to
eliminate potential failure modes in that setup will be
quite the
adventure, which depending on your availability target may
be
a non-issue or a great reason to consider moving to new
space.

/John