Re: How to cool my cpu temperature?
On Sun, Jan 07, 2007 at 08:04:08AM -0600, Hugo Vanwoerkom wrote:
> The problem where I live is the ambient temperature. It is now 8AM and
> the temperature is 21C 70F. That is the case temp also and the mobo temp
> is 34C. The CPU temp is 40C.
>
> But houses here are either built out of corrugated steel, in which case
> you never put a computer in it, or concrete block + concrete roof, like
> ours. Because it never rains from Oct.-May the sun will heat the
> structure so by the afternoon the ambient temp is about 36C, over 90F
> inside.
>
> Air conditioning is prohibitive in expense.
>
Hi Hugo,
So don't condition the air. Remember a (I forget which one) law on
thermodynamcs. The heat transfer rate is proportional to the
temperature differential. If the ambient temp is too high, it doesn't
matter much how fast the air is moving (since evaporation isn't the
issue), the components will still get too hot. Most electronics are
designed for an ambient (to them, not the case) temperature of 25 C max.
If the ambient and case temp is 21 C and the MB temp is 34 then you need
more airflow across the MB (which will also help cool the CPU).
What about water cooling?
You could either directly cool components or cool the air going into the
case only. Here, I don't mean the water cooling stuff for gamers; it
still relies on cool air and is simply a way to remotely increase the
conductive area of the CPU heat sink. I'm thinking more like those for
larger units.
For a discussion of the principles of what I'm thinking about look on
IBM's website. It think there's a redbook or something on the optional
water-cooled doors to the racks for their large pSeries servers like
the 570.
The idea is that you provide cool water to a radiator on the front of
the box with room air blowing across this radiator into the computer.
In IBM's case the water temp is 18 C. Whatever you do, don't drop it
below the dew-point or else you risk condensation.
I'm assuming that you would want to use regular potable water for this
so make sure that your radiator is potable. E.g. don't use a car
radiator or heater core. If you don't have anything that uses water on
a regular basis you can probably use your well as a heat-sink, pump the
water up, through your potable core, then back down the well.
Another option, especially if you have more than one computer, is put
them all in a chest freezer, change the thermostat, and add lots of
thermal mass. Just watch for condensation.
Something else to keep in mind. Many MBs now use what they call "heat
pipes" that are really sealed tubes with refrigerant in them, tilted so
the radiator is higher than the device to be cooled. Refrigerant is
boiled off by the component and it is condensed at the radiator and
dribbles down. If your ambient temp is higher than the boiling temp of
the referigerant (at whatever the pressure is in the heat pipe), then
you wont have any cooling happening at all since refereigerant won't be
flowing.
You may get some other ideas from looking at how cooling is solved in
things like Crays. The Space Shuttle has cooling rads on the inside of
the bay doors; one reason they keep the sunlight out of the bay.
Good luck.
Doug.
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