Radial thermoelectric generator modules for in-line power generation from hot gas streams

Abstract

This paper reports the fabrication and characterization of stackable silicon-micromachined thermoelectric generator (TEG) modules for power generation from hot gas streams. Each module employs radially oriented thermoelements on a thermally insulating polyimide layer extending between inner and outer finned silicon structures. Power is generated by flowing hot gas through the center orifice, which creates a radial thermal gradient across the thermopile. Metal thermoelements are used to demonstrate the concept, resulting in 60 mV open-circuit voltage and delivery of 0.45 µW of power (0.01 mW/cm3 power density) from a single TEG module to a 1.5 kΩ resistive load using a 200 °C hot gas stream. Analytic models indicate that replacing the metal thermoelements with higher-performing semiconductor alloys can increase the output power, e.g. ~0.5 mW (10 mW/cm3) using Bi2Te3 at 200 °C, or ~1.3 mW (27 mW/cm3) using PbTe alloys at 400 °C.