Peltiereffect

Peltiereffect, also called the Peltier effect, is the heating or cooling that occurs at the junction of two dissimilar conductors when an electric current passes through a closed circuit. It was discovered by Jean Charles Athanase Peltier in 1834.

When a current flows through a junction between two different materials, heat is absorbed at one junction and released at the other, depending on the direction of the current. The amount of heat transported per unit current is described by the Peltier coefficient, pi, with Q = pi I for a given junction temperature. The coefficient is related to the Seebeck coefficient S by pi ≈ S T, where T is the absolute temperature; the sign determines whether cooling or heating occurs at a given junction.

The Peltier effect is one of the core phenomena in thermoelectricity, alongside the Seebeck and Thomson effects. It is exploited in solid-state thermoelectric devices known as thermoelectric coolers (TECs) or heaters, which can provide cooling or heating without moving parts. Common thermoelectric materials include bismuth telluride-based compounds for room to moderate temperatures, with higher-temperature applications using materials such as lead telluride and certain skutterudites. Device performance is quantified by the coefficient of performance (COP) and the thermoelectric figure of merit ZT, which constrain efficiency.

Applications include electronic cooling for sensors, laser diodes, and microelectronics, precise temperature control in scientific instruments, and portable cooling/heating solutions. The Peltiereffect enables compact, quiet, and reliable solid-state cooling and heating, albeit with efficiency limitations inherent to current thermoelectric materials.