Abstract: There is an increasing interest in thermoelectric devices even if the efficiency is rather low. Many fields such as aerospace, automotive or building applications are concerned. It is then interesting to model the phenomena involved especially into the thermoelectric legs and to try to optimize the design of the thermoelements.
In a first part, a semi-analytical method has been developed to solve easily the transient case. The Joule contribution is taken into account (introducing a source term in the heat transfer equation) and the effect due to the Thomson coefficient is considered whereas it is often neglected. Thanks to the expressions of the temperature and of the heat flux expressed in the Laplace domain, the quadrupole method is performed. No mesh is required. The whole matrix formulation is given for different initial conditions.
In the second part, the focus is put on the design of a thermoelement applied to Radioisotope Thermoelectric Generators (RTGs). RTGs work by converting heat from the natural decay of radioisotope materials into electricity; the two junctions of the thermoelement are kept at different temperatures and this temperature difference is relatively large. To achieve a better efficiency and as no single thermoelectric material presents high figure of merit over such a wide temperature range, it is therefore necessary to use different materials and to segment them together in order to have a sandwiched structure. In this way, materials are operating in their most efficient temperature range. In this paper, the design and the optimization of segmented thermoelement are proposed and explained on a real test case considered by the Russian firm BIAPOS.

Brief Biography of the Speaker:
Myriam Lazard is associate professor at Institut PPrime University of Poitiers since 2010. Previously she was associate professor, at the Institute in Engineering and Design (InSIC), Ecole des Mines (2002-2010). Her PhD was on the “Modelling of the combined conductive-radiative heat transfer in a semi-transparent medium. Parameters estimation”, Lab. Energetics & Mechanics Theoretical and Applied, (LEMTA), Institut National Polytechnique de Lorraine (2000). Her research interests include heat transfer in manufacturing processes, radiative transfer in semi-transparent media, inverse problems, parameters estimation and thermoelectricity.
She is member of the editorial board of the journal CESES, and Editor in Chief of WSEAS TRANSACTIONS on HEAT and MASS TRANSFER ISSN: 1790-5044.