Power and efficiency calculation and evaluation of material properties in thermoelectric power generators

Thermoelectric elements convert a portion of thermal energy into electrical energy, developing the Seebeck effect. A number of thermoelectric elements can be connected electrically in parallel and/or in series shaping a thermoelectric generator (TEG) device. The generator efficiency, eta, is determined by comparing the amount of electricity produced (P-TEG) to the total amount of heat induced (Q(H)). The possible use of such a device for the recovery of wasted heat can considerably help the world effort for energy savings and the reduction of greenhouse gases. A measuring system and a modeling approach which takes into account the thermal contact resistances have been developed, allowing the characterization of TEG devices under various loads and temperature gradients and thus, the evaluation of material properties. The model was applied on investigating the expected gained power and efficiency, at different places of the exhaust pipe of an intermediate size car with the use of conventional thermoelectric elements. Furthermore, the reliability of a TEG module was examined and the repercussion on fuel consumption is discussed.