[PLUG] Re: local-ish rack suppliers?

[AthlonRob]

On Mon, 2004-03-15 at 10:41, Keith Lofstrom wrote:

> Now, I am imagining modifying one of those Honeywell HEPA air cleaners
> to feed a dryer duct, and run that from outside somewhere to the back
> of a large wooden cabinet, on rollers, with doors front and back.  Too
> wierd and expensive, probably, but it would look nice and be quiet.
> Wood = quiet compared to a metal case.   Of course, wood = flammable,
> too.

I think water cooling is where you need to be looking.  A single 120mm
fan can cool a system fairly well... and very quietly.  Assuming you
aren't using some super-hot video card, you'll do better with water
cooling than with air cooling, just in the temperature department.

> But keep in mind cooling - the insides of computers get too hot anyway,
> and those cheap sleeve-bearing fans fail easily.  Plan on fan upgrades
> (to quiet/reliable) for all your computer cases before you stick them
> in anything closed up.

Invariably, people I know who try to close up their computers come to me
to replace their failing hard disk after about a year.  It just doesn't
work unless it is done properly.

Again... water cooling pretty much helps this out.

> Perhaps another alternative, if it all goes into a sealed metal case,
> is to remove all the computer case covers and operate them open, and
> blow air through the entire cabinet.  I read somewhere that the noise
> from a fan goes up as the 5th (!!!) power of the air velocity, other
> things being equal.  So a 2X radius fan (4x area) moving the same air
> volume will need 1/4 of the velocity, resulting in ( 1/1024 (V^5) x 4 (A) )
> or 1/256 of the noise - 24 dB less.  So imagine a cabinet with a 4
> foot Casablanca-style fan sucking air through a furnace filter and
> blowing air through open cases.

When dealing with traditional air cooling, you *need* that directed flow
over components.  If you have lmsensors installed, watch your CPU
temperature go up as you open the side of your case.  Your drives won't
get the directed air flow, either.  Neither will your video card. 
Instead all the not-hot stuff gets as much air as the hot stuff does.

If you don't direct the air flow, you're going to need a lot more of it
to keep everything cool.  That'll lead to more noise.

> More realistically, you have better things to do than invent funny
> cases with big fans.  Do the fan mods, find some metal shelving
> with an open front, line it with sound-absorbing material (fiberglass
> insulation?) and turn it around so you don't have to look at your
> computers.  But don't restrict the airflow, or Mr. CPU will get cranky
> and write binary obscenities on your hard disk, and Mr. Power Supply
> will sing some flame thrower kareoke.

Water cooling is going fairly mainstream in the last few years.  Check
it out... you can cool a whole system, assuming it isn't something
really hot, with a single 120mm fan.  Toss a second 120mm fan in there
to cool the PSU and disks with a little added airflow if you want...
120mm fans are darned quiet compared to what is in your system now.

Rob