Trying to retrofit an old Peltier wine cooler and I a question about the wattage and heat calculations.

If I have a 12V power source (switched) so the maximum Wattage it can convert to heat is (105W)

If I were to connect some sort of cooling system capable of dissipating 120W of heat (such as a CPU cooler)

Would that be adequate heat removal to allow the cool side to continue to decrease the temperature to below ambient? Or have I oversimplified the heat movement calculations too far?


simulate this circuit – Schematic created using CircuitLab

  • \$\begingroup\$ Sorry if i have missed something obvious it's been years since my last Electrical Engineering class. \$\endgroup\$ Commented May 15, 2020 at 3:57
  • \$\begingroup\$ A cooler is rated in degrees rise per Watt at rated power. So if eg tour cooler was capable of 1 C/W at 120 W then rise would be 120 C above ambient. Not good in this case. \$\endgroup\$
    – Russell McMahon
    Commented May 15, 2020 at 4:33
  • \$\begingroup\$ The cooler also has to remove more than just the power you're applying since the TEC pumps energy from the cold side to the hot side. \$\endgroup\$ Commented May 15, 2020 at 5:06

1 Answer 1


A peltier hot side has both the wattage of the heat your moving, and the electrical power your using to move that heat, meaning you will generally need to heat sink at least double what your feeding in to it,

The higher the temperature difference, the higher the voltage, the higher the heat flow the higher the current. It more efficient to drive a peltier with a moderately high frequency PWM or analog voltage source, as the efficiency is lower when switching it on and off from the full supply voltage.


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