Thermo Electrical Generator Improved Model Mihail Octavian Cernaianu 1,a , Adrian Cernaianu 2,b , Cosmin Cirstea 1,c and Aurel Gontean 1,d 1 ”Politehnica” University of Timisoara, Applied Electronics Department, Timisoara, Romania 2 University of Craiova, Faculty of Mechanics, Material Technologies Department, Craiova, Romania a mihail.cernaianu@etc.upt.ro, b acernaianu@gmail.com, c cosmin.cirstea@etc.upt.ro, d aurel.gontean@etc.upt.ro Keywords: Thermo electric generator (TEG), Seebeck coefficient, thermo-electrical model, automatic measuring system. Abstract: This paper describes the implementation of an automatic measuring system used to acquire the voltage drop from a gradually heated TEG output with and without load. This will help determine the Seebeck coefficient and the internal resistance of the thermo electrical generator. The Seebeck coefficient is one of the TEGs main characteristic and gives valuable information about the output voltage the TEG can generate if its two sides are maintained at different temperatures. Some thermo electrical module (TEM) manufacturers give a constant Seebeck coefficient value for their products while measurements prove that in fact it is temperature dependent. The purpose of this research is to accurately investigate the Seebeck coefficient and internal resistance values depending on temperature and determine the TEMs performance. Using the experimental results we propose to later create an improved thermo electrical model for the TEG. 1. Introduction The Seebeck effect was first discovered in 1821 by the German physicist Thomas Johann Seebeck. Given a uniform temperature in a closed circuit that is formed by metals, the electromotive contact forces compensate each other and their algebraic sum is zero. Seebeck discovered that this compensation doesn’t persist and that an electromotive force appears if one of the contact points between two metals has another temperature than the others [1]. The Peltier effect is the presence of heat at the contact region of two metals when they are electrified [1]. In bulk devices for generation or cooling applications, thermocouples have a typical geometry that consists of two ingot-shaped pellets (thermo-elements) of semiconducting material having dimensions in the order of millimeters connected at one end with an electrically conducting metal strap [2]. A standard TEM is comprised of several thermo-elements thermally connected in parallel and electrically in series. The figure of merit ZT, defined as 2 S ZT k σ = , where σ is the electrical conductivity, S the Seebeck coefficient and k the thermal conductivity, indicates the thermodynamic efficiency. A higher value is an indication of greater efficiency. Measurements of the TEMs parameters have already been made in order to deduce the quantities important for theory and application [4]. In existing thermo electrical models, TEMs parameters are considered constants when in fact they vary with temperature. The purpose of this research is to 2012 International Conference on Power and Energy Systems Lecture Notes in Information Technology, Vol.13 978-1-61275-011-8/ 10/ $25.00 ©2012 IERI ICPES2012 343