Peltier Current and Heat Reversal

The Peltier effect is a thermoelectric phenomenon where a current passing through a junction of two different conductors drives a heat flow. In a thermoelectric cooler, this reversible heat transport can be used to extract heat from a cold reservoir, provided it overcomes the inherent parasitic effects: Joule heating (resistive losses) and thermal conduction. By reversing the direction of the electrical current, the reversible heat pumping also reverses direction, whereas the irreversible Joule heating strictly adds thermal energy regardless of current direction.

Interactive Experiment

You can explore these relationships in the Peltier Current and Heat Reversal module. The simulation allows you to adjust the current, temperatures, and Seebeck coefficient to observe the resulting heat flows.

1. Set the Current to 2 A, with Cold temperature at 300 K and Temperature gap at 0 K. Observe the positive cooling heat indicating active cooling.
2. Change the Current to -2 A. Notice that the reversible heat arrow flips direction, and the cooling heat becomes negative (net heating), but the Joule heat arrow remains pointing into the cold side.
3. Increase the Temperature gap to 20 K (with current back at 2 A). See how the conductive leak increases, eventually overwhelming the reversible heat pumping and resulting in a loss of net cooling.
4. Set the Seebeck coefficient to 0. Observe that all reversible heat pumping ceases, leaving only Joule heating and thermal conduction.