Direct conversion of waste heat into electric energy by thermoelectric generators
- The energy crisis and environment deterioration are two major problems for the 21st century. Waste heat recovery offers many opportunities to make a global contribution to this challenge. Key concepts such as waste heat recovery are the basic ideas in thermoelectricity. A part of waste heat is produced by solid-fuel stoves. Nevertheless, the quantity of high-performance solid-fuel stoves is increasing very quickly for economic and environmental reasons. These sophisticated stoves need electricity for the pump for water circulation and the control system. Thermoelectric generators (TEG) could help with this issue. This work aims to present an experimental validation of integrating a thermoelectric generator into a solid-fuel stove. An economic comparison between the most common Bismuth Telluride (Bi2Te3) module and the newly developed half-Heusler modules is complete. An experimental set-up was built to optimize the common (Bi2Te3) modules and test the newly developed half-Heusler modules from an entire system point of view. An assessment of thermoelectric technology potential, module prices, further material developments and applications is completed. Based on the literature research and a Computational Fluid Dynamics (CFD) simulation software the first prototype was built. This set-up is composed of a thermal loop with a hot gas source, a cold fluid, a hot fin exchanger, and thermoelectric modules. The number and the place of these modules are changed to study different configurations. A specific maximum power point tracker DC/DC converter charging a battery is added in order to study the electrical power produced by the module. Different operating points of hot inlet gas airflow were tested for the Bismuth Telluride and half-Heusler modules. The Bismuth Telluride module was tested under real-life conditions using the exhaust of the solid-fuel stoves without influencing the combustion chamber.
