uh said:
There's a thing called a Thermo electric cooler. It's a neat little
device that when you put electricity to it, gets really cold on one
side & hot on the other. (Peltier effect).
I have a few of these (Bought 'em from melcore.com they have some cool
but too tech. for me software free on their site, BTW) and I want to
use one on that PC that I'm *STILL* waiting for parts for.
My CPU is a AMD Sempron 2800+ 2.0GHz Socket A Processor OEM and I
bought a THERMALTAKE A1492 Volcano 8 CPU Cooler. I had planned to
sandwich the TEC between the Volcano & the CPU using Thermal Grease,
but I thought I'd better check with the gurus first.
Wadaya say?
Oh btw the TEC runs on 12v DC. Where should I take that from?
(A7N8X-E-Deluxe Motherboard)
Thanx!
Well, you have the basic functional description about right but are way
short on the engineering.
A peltier pumps heat from one side to the other so one side gets 'cool'
while the other gets 'hot'. Now, it also takes energy to do that (power at
12 volts in your case), which also needs to be dissipated as heat on the
'hot' side.
Without going into the nitty gritty of equations, and all, the upshot to
that first bit is it takes twice as much, or more, energy to pump the heat
as the heat you're trying to move (depends on just how 'cold' you want the
cold side) so if your heatsink was designed to handle a 100 watt processor
it's now got 300 watts, or more, to get rid of and, woops.
The second upshot is your power supply now has three times as much 'CPU
related' power to provide and if the system needed 9 Amps@12V to power the
CPU alone it now needs to put out 27 Amps, at least. Plus the attendant
problems of getting PSU heat losses out of the PSU/case as well.
The amount of cooling is dependent on the size of the peltier and the
amount of power you pump into the thing. How much heat is the one you
bought supposed to be able to pump, and to what temp? It obviously has to
be at least as much as the CPU puts out just to stay even, more to get any
'cooling'.
On the practical side, you see it takes a ton of power so pumping ambient
heat just burns more power to no end and, worse, the distance from the
'hot' side to the 'cold' side is simply the thickness, or thinness, of the
peltier so unless you insulate the two sides from each other you simply
pump heat in a circle, burning power all the time for little to no effect.
Now, assuming you get over the hurdles of a large enough peltier, the huge
power requirements, and have it insulated well enough so that you're
actually getting some decent cooling out of it you then have the potential
problem of condensation on the processor and immediately surrounding
components as it/them being cooler than the ambient air will cause it/them
to draw the water out just as a cold water glass sweats on a warm summer's day.
Needless to say, water is a bad thing for electronics and finding some
means to prevent air from getting to the CPU is almost, if not, impossible
so you generally try to limit the cooling to above ambient, which is not as
easy as it sounds with the processor power cycling all over the place as
the system is used and goes in and out of idle/power saving modes. Pump
enough heat to handle the 100 watt 'max' and icebergs form on the thing at
idle. So now you likely need some way, a controller, to throttle 200+ watts
worth of power into the peltier based on CPU temperature and that isn't a
trivial exercise either. (or keep the CPU at full power all the time, or
throttle fans so the peltier efficiency drops, or some other means that
generally means tons of wasted power)
You also need a cold plate on the cold side but enough is enough.
I don't mean to rain on your parade but you need to go back to that "too
tech" stuff, figure it out, and do the engineering because simply slapping
one onto the bottom of a heatsink isn't likely to work these days and,
worse yet, will likely destroy the processor in the attempt because, while
it pumps heat, a peltier also blocks the heat it isn't capable of pumping.
So, if the processor is putting out 100 Watts and the peltier is only
pumping, say, 80, then it will act as if you wrapped the processor in a
blanket and instead of 'cooling' the thing will shake and bake itself into
a cinder with the difference in how much heat it's not able to pump
determining how long it takes to bake; like 3 seconds vs 5.
Or it'll overload the PSU causing an immediate over-current shutdown
thereby saving you the pain and misery of it powering up to cook itself.
