Radial Thermoelectric Generator Modules for In-Line Power Generation From Hot Gas Streams

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.