Thermoelectric Energy Conversion in a Lid-Driven Cavity Microgenerator Using Nanofluids

The present research seeks to characterize and evaluate a lid-driven cavity-TEG system to harness residual energy. Therefore, the behavior of water and a nanofluid (SiO2) in a rectangular lid-driven cavity is numerically studied. The Navier-Stokes and energy conservation equations are solved using the finite difference method in Python. The fluid behavior is analyzed with a Reynolds number of 100, Richardson number of 100-77 and variable lid direction. Likewise, a thermoelectric module is integrated in the cavity, and the power generated by varying the size and number of thermocouples is studied. The results obtained contribute to the characterization of applicable thermal systems for their optimization. In the cavity, when the lid direction is positive, its interaction with the buoyant flow generates a vortex on the right side, and multiple vortices when it is in the negative direction; the isotherms present horizontal and vertical stratification in both cases. μTEG generates the most power with a 0.07 mm thermocouple size in the negative lid direction case, with an inlet gradient temperature of 8 K. SiO2 (Ri = 77) showed a 23% increase in power output compared to water (0.318 μW/cm² and 0.461 μW/cm², respectively). With a 30% higher inlet gradient temperature (SiO2 at Ri = 100, ΔT = 10.4 K, 0.569 μW/cm²), it generated 79% more power output compared to water.