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 = RL/RTEG), are simplified thanks to the devised maximum efficiency to temperature gradient (βmax = η/ΔT) metric. Quasi-computational results of βmax show that the collective Seebeck coefficient Bi2Te3–PbTe (α˜) design sustains a higher electrical load in relation to the homogeneous Bi2Te3 and PbTe materials. The average (α¯) and collective (α˜) Seebeck coefficient Bi2Te3–PbTe configurations, in comparison to Bi2Te3 and PbTe, exhibit a considerably higher (60–68%) source and sink thermal resistance matching (ΘTEG = ΘHx). The proposed segmented Bi2Te3–PbTe (α˜) TEG yields a peak efficiency of 5.29% for a ΔT of 324.6 K.

► A design methodology for segmented TEGs is formulated on theoretical modeling.
► The efficiency and geometry of Bi2Te3, PbTe and Bi2Te3PbTe are derived for ΔT = 325 K.
► Bi2Te3PbTe exhibits an efficiency/ΔT ratio intermediate to Bi2Te3 and PbTe.
► (α¯) and (α˜) Bi2Te3PbTe exhibit a 60–68% thermal resistance match than Bi2Te3 and PbTe.