Peltiereffekt

The Peltier effect, or Peltier-Effekt in German, is the heating or cooling that occurs at the junction of two dissimilar conductors or semiconductors when an electric current passes through the junction. It is one of the thermoelectric effects, alongside the Seebeck and Thomson effects, and was discovered in 1834 by Jean Charles Athanase Peltier.

The effect is described by the Peltier coefficient, Pi, which relates the heat carried per unit current at a junction. Pi is temperature dependent, and it is related to the Seebeck coefficient S by Pi ≈ S · T, where T is the absolute temperature. The rate of heat transfer at the junction is Qdot = Pi · I, with I the current. Reversing the current reverses which side of the junction heats or cools.

Thermoelectric cooling devices, commonly called Peltier modules or thermoelectric coolers (TECs), use many p-type and n-type semiconductor elements connected electrically in series and thermally in parallel between two ceramic plates. When current flows, one junction absorbs heat from the cold side while the other releases heat at the hot side; reversing the current reverses this effect. TECs are solid-state devices with no moving parts, suitable for compact cooling or heating, and are scalable in size.

Applications include cooling of electronic components, laser diodes, infrared detectors, and portable refrigeration, as well as precise temperature control for sensors and scientific instruments. Advantages include quiet operation and robustness; limitations involve relatively low efficiency compared with conventional refrigeration and dependence on effective heat sinking. Material performance is captured by the thermoelectric figure of merit ZT, with common room-temperature materials based on bismuth telluride compounds.