Performance of a Composite Thermoelectric Generator with Different Arrangements of SiGe, BiTe and PbTe under Different Configurations

In this study, we analyze the role of the thermoelectric (TE) properties, namely Seebeck coefficient α, thermal conductivity κ and electrical resistivity ρ, of three different materials in a composite thermoelectric generator (CTEG) under different configurations. The CTEG is composed of three thermoelectric modules (TEMs): (1) two TEMs thermally and electrically connected in series (SC); (2) two branches of TEMs thermally and electrically connected in parallel (PSC); and (3) three TEMs thermally and electrically connected in parallel (TEP). In general, each of the TEMs have different thermoelectric parameters, namely a Seebeck coefficient α, a thermal conductance K and an electrical resistance R. Following the framework proposed recently, we show the effect of: (1) the configuration; and (2) the arrangements of TE materials on the corresponding equivalent figure of merit Zeq and consequently on the maximum power Pmax and efficiency η of the CTEG. Firstly, we consider that the whole system is formed of the same thermoelectric material (α1, K1, R1 = α2, K2, R2 = α3, K3, R3) and, secondly, that the whole system is constituted by only two different thermoelectric materials Entropy 2015, 17 7388 (αi, Ki, Ri = αj, Kj, Rj 6= αl, Kl, Rl, where i, j, l can be 1, 2 or 3). In this work, we propose arrangements of TEMs, which clearly have the advantage of a higher thermoelectric figure of merit value compared to a conventional thermoelectric module. A corollary about the Zeq−max for CTEG is obtained as a result of these considerations. We suggest an optimum configuration.