Enhancing solar thermoelectric generator performance using metal oxide layer absorbers under concentrated solar radiation

Abstract

Solar Thermoelectric Generators (STEGs) hold promise for sustainable energy, with ongoing efforts to enhance efficiency through advanced thermal absorbers. This study evaluates the performance of STEGs using graphite sheet (GS) and metal oxides layer (MOL) absorbers under solar concentrations of 20, 40, 60, and 80 suns. Performance metrics, including short-circuit current (Isc), open-circuit voltage (Voc), maximum power output (Pmax), and efficiency (η), were measured experimentally using the KIRAN-42 solar simulator and compared with COMSOL Multiphysics simulations. The MOL-based STEG outperformed the GS-based counterpart, achieving Pmax (η) values of 0.559 W (1.75 %), 1.818 W (2.84 %), 3.071 W (3.2 %), and 3.762 W (2.94 %) at 20, 40, 60, and 80 suns, respectively, compared to 0.308 W (0.96 %), 1.120 W (1.75 %), 1.984 W (2.1 %), and 2.670 W (2.1 %) for the GS-based STEG. Experimental and simulation discrepancies were minimal at lower concentrations (1.9 % and 6.4 % at 20 suns) but increased at 80 suns (32.4 % and 41.7 %). Both approaches showed strong linear correlations between Pmax and solar concentration (R2 > 0.98). Low RMSE values (0.45 for GS, 0.81 for MOL) further validated the models. This study underscores the superior performance of MOL absorbers and provides insights for optimizing STEG designs.