Designing high efficiency segmented thermoelectric generators

Improving the efficiency of thermoelectric devices is critical to their widespread adoption. Here a design methodology, formulated on computational and analytical modeling, derives the optimum efficiency and geometry of segmented Bi₂Te₃-PbTe Thermoelectric Generators (TEGs) between ≈298 K and ≈623 K (ΔT ≈ 325 K). Comparisons between the different TEG designs, in terms of the electrical load to TEG electrical resistance ratio (m = R_L/R_TEG), are simplified thanks to the devised maximum efficiency to temperature gradient (β_max = η/ΔT) metric. Quasi-computational results of β_max show that the collective Seebeck coefficient Bi₂Te₃-PbTe (α̃) design sustains a higher electrical load in relation to the homogeneous Bi₂Te₃ and PbTe materials. The average (ᾱ) and collective (α̃) Seebeck coefficient Bi ₂Te₃-PbTe configurations, in comparison to Bi ₂Te₃ and PbTe, exhibit a considerably higher (60-68%) source and sink thermal resistance matching (Θ_TEG = Θ_Hx). The proposed segmented Bi₂Te₃-PbTe (α̃) TEG yields a peak efficiency of 5.29% for a ΔT of 324.6 K.