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Exploring the potential for waste heat recovery during metal casting with thermoelectric generators: On-site experiments and mathematical modeling

Børset, Marit Takla, Wilhelmsen, Øivind, Kjelstrup, Signe, Burheim, Odne Stokke
Energy 2017 v.118 pp. 865-875
cold, heat recovery, heat transfer coefficient, industry, mathematical models, power generation, silicon, temperature, thermoelectric generators, wastes
Thermoelectric power generators are scalable and simple systems for recovering waste-heat disposed by the industry. We combine on-site measurements and a mathematical model to study the potential for power generation with this technology from heat available from casting of silicon. We implement a 0.25 m² thermoelectric generator (TEG), based on bismuth-tellurium modules, in the casting area of a silicon plant. The measured peak power is 160 W m⁻² and the corresponding maximum temperature difference across the modules is 100 K. We predict a large potential to increase the power generated beyond the measured values. For a two-fold increase of the heat transfer coefficient at the cold side, and by moving the generator closer to the heat source, we predict that the power output can reach 900 W m⁻². By tailoring the design of the TEG to the conditions encountered in the industrial facility, it is possible to generate more power with less thermoelectric material. We provide guidelines on how to design thermoelectric systems to maximize the power generation from waste heat given off from silicon during casting.