The Peltier Cooled PC:
Considerations For Power Consumption And Heat
Peltiers are rated for the absolute maximum heat load
they can move with no temperature differential. Above maximum, the cold plate temperature
will actually be HOTTER THAN THE HEATSINK!!! Most Peltiers are rated close to 16 Volts,
and move even less maximum heat in a 12 Volt PC. The useful temperature drop of a
Peltier must also be de-rated by a hotter running heatsink.
The Peltier on my AOC ICEBERG is clearly marked PT4-12-40 MELCOR. It is a PolarTec.
Designed to pump no more than 32Watts at 14.4V. http://www.melcor.com/ptseries.htm
That sure explains why my Celeron ran so much hotter
than with a plain regular heatsink! I still might use this sucker on a video card or low
power CPU, perhaps my Rise MP6.
I could find no published performance curves for my wimpy MELCOR PolarTec. Another
company, Americool, had some great charts. I found this one particularly useful. Take a
look at a typical 55 Watt Nord TM-127-1.4-6.0-M rated at 15.5V
While adequate, it looks like even this single Peltier
is struggling to keep an OC'd Celeron cool. If a higher temperature differential is
required, suppose I team up two 12V Peltiers in parallel? A dual-chilled 650 Celeron
should see almost a 37C drop compared to just 10 with one. I would also have 132
Watts of heat radiating into my chassis!! (12V * 3.75A) + (12V * 3.75A) + 42W = 132W.
WaterCooling the Peltiers looks very tempting.
Do I even have enough 12V power to run a pair of Peltiers? Here is my power supply.
As you can see from the typical 250Watt supply above,
there is barely enough 12Volt current to run a single Peltier device. A much bigger power
supply would certainly be required for two.
Sparkle's 400Watt model can deliver 15Amps at 12V. With a supply like that, it could be
done!
A side note about power supply bridging: It is possible to run a few low current fans at
15.3V by wiring them from -12 to +3.3. But be warned. There is not enough negative current
available to run even one Peltier in this way. Never bridge anything to the -5V line,
there is negligible current available from -5. Never hook up the fan speed sensor wire
when you bridge. It could easily fry your board.
For any serious project I might try a bench tech's 30Amp 14.4V car audio supply. They
emulate a typical car battery charging from an alternator, and are quite easy to find. You
can run as many fans and Peltiers off one of these as sanity will allow.
Ken Peter
kenpeter@hotmail.com
Next page: Why the Peltier didn't
work
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