Abstract
When the electrical conductivity, σ, thermal conductivity, λ, and thermopower, S, of a material are all assumed to be constant over the temperature range of interest, then the well-known thermoelectric (TE) figure of merit, Z = σS 2/λ, arises as part of the derivation of conversion efficiency in a TE generator. However, there are an infinite number of parameter sets (σ, λ, S) that yield any given Z. So, are they truly equivalent? This paper reviews the historical basis for Z as a metric for TE quality and discusses results of simulations on three systems having different parameter sets but the same Z. The three systems exhibit different power generation capabilities, illustrating that Z is not sufficient to specify the likely performance of a TE material in a system. Instead, a systems analysis is required that incorporates, at a minimum, source and sink temperatures and thermal resistances.
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Nemir, D., Beck, J. On the Significance of the Thermoelectric Figure of Merit Z . J. Electron. Mater. 39, 1897–1901 (2010). https://doi.org/10.1007/s11664-009-1060-4
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DOI: https://doi.org/10.1007/s11664-009-1060-4