Analysis of Thermoelectric Phenomena

AltaSim Technologies, Columbus, Ohio

Thermoelectric phenomena provide the direct conversion of heat into electricity or electricity into heat. The phenomena are described by three related mechanisms: the Seebeck, Peltier, and Thomson effects. The Seebeck effect describes the conversion of temperature differences directly into electricity; at the atomic scale, an applied temperature gradient causes charged carriers in the material to diffuse from the hot side to the cold side, generating a current flow. The Peltier effect describes the production of heat at an electrified junction of two different materials — the forced flow of charged carriers creates a temperature difference. The Thomson effect describes the heating or cooling of a current-carrying conductor in the presence of a temperature gradient.

Figure 1: Temperature distribution resulting from imposition of voltage to Bismuth Telluride pellets — the **Peltier Effect**.

Thermoelectric devices using thermoelectric effects have found many applications including temperature measurement, solid-state heating or cooling, and direct energy conversion from waste heat. Despite their relatively low efficiency, these devices have found widespread use in innovative technologies requiring highly localized heating/cooling or temperature measurement in small volumes.

Due to the increase in exploitation of devices using Seebeck-Peltier phenomena, AltaSim Technologies has implemented analysis of the Seebeck-Peltier effects into COMSOL Multiphysics V 4.2. The governing equations for heat energy and electric current have been implemented in the weak form, together with the temperature dependence of critical electrical and thermal material properties. The governing equations incorporate the Peltier and Seebeck coefficients to allow a full description of the thermoelectric phenomenon.

Figure 2: Electric potential for a thermoelectric module made up of an array of Bismuth Telluride pellets due to imposition of a non-uniform temperature distribution — the **Seebeck Effect**.

Analysis of the behavior of Bismuth Telluride p-n junctions when a voltage is applied is shown in Figure 1, with the generation of focused heating and cooling due to the Peltier effect. Similarly, imposing a thermal gradient on an array of Bismuth Telluride pellets results in the generation of a potential across the surface of the module, as shown in Figure 2, due to the Seebeck effect.

This work was performed by S.P. Yushanov, L.T. Gritter, J.S. Crompton, and K.C. Koppenhoefer of AltaSim Technologies using COMSOL Multiphysics. For more information, contact: J. Crompton at This email address is being protected from spambots. You need JavaScript enabled to view it., or visit http://info.hotims.com/34458-132 .