Electro–thermo–mechanical assessment of thermoelectric modules under dual boundary conditions

• Electro–thermo–mechanical analysis of TE modules under dual boundary conditions. • Comparative evaluation reveals distinct trends in CT vs. CHF operating regimes. • Structural optimization balances power generation efficiency and stress reduction. • Numerical predictions validated by experiments with <2.16 % error margin. • Findings provide design guidelines relevant to industrial waste heat recovery. Efficient utilization of waste heat is essential for sustainable energy systems, yet the design of thermoelectric (TE) modules remains limited by fragmented assessments of their performance. Previous studies typically address either constant temperature (CT) or constant heat flux (CHF) conditions, with a primary focus on electrical output. Such simplifications overlook the combined influence of thermal boundary conditions and thermomechanical stresses, limiting the applicability of findings to practical environments. This study presents a comprehensive electro–thermal analysis of TE modules under both CT and CHF conditions, examining the effects of leg width, length, and number. Numerical simulations, validated by experiments, reveal that optimal design strongly depends on boundary conditions. Under CT, output power is governed by resistance–current trade-offs, whereas under CHF, voltage response and thermal saturation effects dominate. The thermomechanical analysis shows that CHF yields lower stress concentrations but larger deformations, indicating improved structural stability compared to CT. Experimental results confirm the accuracy of the model, with maximum deviations below 2.2 %. By integrating dual boundary conditions with coupled electro–thermal–mechanical evaluation, this work provides quantitative design guidelines for TE modules. The results offer direct engineering value for optimizing module geometry, enhancing efficiency and reliability in industrial waste heat recovery.