Thermoelectric Energy Harvesting for Exhaust Waste Heat Recovery: A System Design

Thermal energy harvesting for high-speed moving objects is particularly promising in providing an efficient and sustainable energy source to enhance operational capabilities and endurance. Thermoelectric (TE) technology, by exploiting temperature gradients between a heat source and ambient temperature, can provide a continuous power supply to such systems, reducing the reliance on conventional batteries and extending operation times. However, the integrated thermoelectric generator (TEG) system design research is far behind materials development. In this study, both experimental and numerical studies of TEG systems are designed and conducted to recover thermal energy. An integrated proof-of-concept platform is developed to simulate an exhaust gas emission system and demonstrate the designed TEG system performance. Triangular plate-fin heat exchangers are designed to collect heat from exhaust pipelines such as engine exhaust gas. While longitudinal trapezoidal fin cylindrical heatsink is designed for dissipating heat via forced convection, particularly for high-speed moving objects, the heatsink design is optimized using finite element analysis (FEA) simulations to maximize the temperature gradient and electrical output power. As a result, under a temperature gradient (ΔT) of 190 °C with commercial bismuth telluride-based TE modules, a maximum system output power of 40 W is achieved experimentally. Furthermore, a computational simulation is conducted to showcase the feasibility of the current system design under high-speed moving vehicle conditions. This study provides an advanced TEG system design bridging the TE device and integrated system transition and represents a potential advancement in the pursuit of high-speed moving objects such as autonomous and longer-lasting aerial platforms.