Optimized design and performance evaluation of a flexible thermoelectric generator for Low-thermal heat waste energy harvesting

The escalating demand for sustainable energy solutions has spurred exploration into thermoelectric generators (TEGs), which possess the capacity to transform heat into electrical energy. This research focuses on the development of a flexible thermoelectric generator (FTEG) engineered with an optimized structure aimed at maximizing the utilization of heat energy sourced from electric housewares and human body heat. Employing a polyimide (PI) film substrate and a flexible high thermal conductivity silica-AlN composite layer for enhanced thermal dissipation on the cold side, the FTEG exhibits exceptional flexibility and efficacy in harnessing body waste heat under vertical temperature gradients for powering portable electronic devices. Besides, between the thermoelectric legs, there are filled with silica aerogel to enhance thermal insulation, allowing the heat flow to pass through the thermoelectric legs effectively. The performance evaluation of the FTEG reveals convincing outcomes. At room temperature (23 degrees C), the FTEG achieves an open-circuit voltage of 35 mV and a peak power output of 110.2 mu W through the conversion of human body heat. Moreover, under a temperature gradient of 50 K, the FTEG yields an open-circuit voltage of 173 mV, a power output of 4.5 mW, and a power density of 127 mu W/cm2 under a 2 Omega load resistance. Furthermore, the FTEG demonstrates its versatility by effectively converting waste heat from the human body into usable electricity, thereby powering electronic watches and LED lights post-voltage enhancement with a DC booster. Additionally, the FTEG is harnessed for waste heat harvesting for battery charging purposes. Additionally, this study introduces a state-of-charge (SOC) prediction methodology for monitoring the battery charging process, highlighting the potential for integrating human body energy harvesting with advanced energy management paradigms.