[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: DATACENTER: AC and colo sizing question.

Wasn't expecting to remove oxygen or remove cooling from humans.  Does this
mean you can't help with a real answer?

-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Thursday, February 10, 2000 11:21 AM
To: David Labuskes
Cc: [email protected]
Subject: RE: DATACENTER: AC and colo sizing question.

What about humans, who can't stey too long in temperature above 75?

On Thu, 10 Feb 2000, David Labuskes wrote:

> I've been working on an idea...
> My question is this.  Everything about data center environmental issues is
> centered around ambient temperature, etc.  I recognize that these should
> 75 degrees, 55 humidity, etc.  But if you put your hand next to the air
> exhaust of a server or even just touch one...you know that they are hotter
> than 75 degrees.  
> My thoughts are to reduce the size of the "room" dramatically and create
> environment of dust free rapidly moving air that will allow for the
> of heat at a rapid pace.  To make it all work though, I need to know what
> the maximum operating temperature is for this equipment.  Not the "room"
> temperature.  But more realistically, the motherboard or circuit board
> operating limitations.
> I apologize if the question doesn't make sense.  Please feel free to reply
> privately or via the list.
> Thanks in advance for any and all information.
> David Labuskes, RCDD/LAN, CSI
> -----Original Message-----
> From: Julian, Dennis R. [mailto:[email protected]]
> Sent: Thursday, February 10, 2000 9:46 AM
> To: foo; [email protected]
> Subject: RE: DATACENTER: AC and colo sizing question.
> I agree, an educated client is a wonderful thing.  In regards to peak
> cooling if you have over cooling what you lose is the ability to control
> humidity. It may feel cold and damp.  The other concern is if the A/C
> have compressors rather than a central chilled water source the increased
> number of starts resulting from short cycling may shorten the unit's life
> and increase the maintenance required.
> But being over cooled is better than over heated.  One way to deal with
> is through multiple units and redundancy.  With multiple units you can
> in by manually or automatically turning on additional units as the load
> increases (or as the temperature rises).  This can be done by using
> redundant units that also provide the ability to maintain cooling when
> unit(s) are down for maintenance or problems.
> Dennis R. Julian, P.E., RCDD
> Technical Associate
> Critical Facilities Design Group
> van Zelm Heywood & Shadford, Inc
> Mechanical and Electrical Engineers
> 29 South Main Street West Hartford, CT 06107-2420
> Phone (860) 521-4329 x373    Fax (860) 521-5620
> [email protected]
> www.vanzelm.com
> -----Original Message-----
> From: Roeland M.J. Meyer [mailto:[email protected]]
> Sent: Wednesday, February 09, 2000 10:40 PM
> To: foo; [email protected]
> Subject: RE: DATACENTER: AC and colo sizing question.
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of foo
> > Sent: Wednesday, February 09, 2000 6:54 PM
> >
> > Ken Woods wrote:
> > > On Wed, 9 Feb 2000, foo wrote:
> > >
> > > 8.34 A @ 120 = 1 KVA
> > > Total KVA * 2728 = BTU
> > > 12000 BTU per ton of air.
> > >
> > > Also add whatever heat load you have from lights, people, walls,
> > > equipment (UPS and air unit, etc)
> >
> > My question is not so much how to calculate cooling for a known
> > load, but rather how to deal with transient increases in load while
> > equipment is being staged or housed temporarily or whatever as well as
> > gradual increases over time (as equipment is added permamnently). As I
> > led to believe that engineering cooling for peak load would be very
> > inefficient and/or ineffective during times of non-peak load, I'm
> > as to what your suggestions may be to alleviate this problem.
> It is not near as inefficient as losing equipment due to heat-death. This
> the inevitable result of NOT planning for peaks. Generally, add up the
> usage numbers on all the equipment you are installing, allow for 5 warm
> bodies, add 30% for additional equipment arriving on a 100 degree day, and
> you should have enough. I like 70F +/- 5F.
> > > If I may, I suggest you hire an engineer that has a basic grasp on
> > > you're trying to do, and isn't trying to guess. There are several on
> > > list that would be glad to work for you.
> >
> > I'm not at all adverse to hiring someone to help us with this, however
> > like to understand it a bit better before going that route. In my
> > experience plenty of facilities haven't gotten this quite right even
> > "experts" on board (I've been a customer or visitor in quite a few
> > Internet Data Centers with serious environmental problems), so simply
> > signing away the responsibility to some third party without first
> > educating myself a bit doesnt make me entirely comfortable.
> You'll find, on investigation, that recommendations were usually
> under-followed due to desire to reduce costs. The cost difference between
> 3 ton AC unit and a 5 ton unit is amazing. Many managers figure that they
> can "tough it out" during the few hot days, or decide to "policy exclude"
> additional equipment. More often, that manager gets another offer,
> and their successor doesn't have their notes and they have to take the hit
> on their watch.