Effects of Temperature Uniformity and Nonuniformity on Thermoelectric Generator Performance Across Hot and Cold Sides

Solar Thermoelectric Generators (STEG) are gaining attention for clean energy but face nonuniform temperature distribution due to optical concentrators and heat sinks. While prior studies used central circles or identical squares to represent temperature variations, this paper examines six circular and rectangular patterns. Using COMSOL, the TEG module was simulated under four boundary conditions: (1) uniform temperatures on both sides, (2) six patterns on the hot side, (3) six patterns on the cold side, and (4) six patterns on both sides for the first time. Experimentally, the I-V and P-V characteristics of STEG were measured using the capacitor technique for four concentration ratios (20, 40, 60, and 80 suns) obtained using the KIRAN-42 simulator. Simulations aligned well with all experiments under condition (1). The 3rd circular and rectangular pattern matched 11 times, while the 1st pattern matched once under conditions (2) − (4). The Root Mean Square Error (RMSE) between the measured and simulated Pmax, based on average measured temperatures, was 0.505. For condition (1), the RMSE was 0.017, while for conditions (2) − (4), it was 0.027 (0.033), 0.031 (0.031), and 0.044 (0.047) for the 3rd circular (rectangular) pattern, respectively. These findings indicate improved alignment between experiments and simulations.