Simulation of Thermoelectric Generator Modules for Energy Harvesting in Cryo-fuel Applications

Kurzfassung

Thermoelectric (TE) generators are an option for waste heat recovery in a large diversity of applications, such as automotive, aerospace and industrial processes with high energy throughput. The rapid deployment of cryogenic fuels (liquid H2, LNG) in road and rail transport creates a new source of low‑temperature waste heat at the fuel‑evaporator. Harvesting this heat with thermoelectric generators (TEGs) offers a compact, solid‑state solution for auxiliary power, but the extreme temperature asymmetry (cold side = ‑190 °C to ‑80 °C, hot side = 0 °C to 500 °C) demands a dedicated module design. We present a comprehensive 1D simulation of single-stage and segmented TE modules comprising Bi2Te3, Skutterudites and Mg based alloys. The model uses measured temperature-dependent material properties, geometries of the single pellets and TE module with variation of the filling factor and considers electrical and thermal contact resistances. The boundary conditions of an experimental setup for TE module testing at cryogenic temperatures have been used as input parameters. The experimental results of module characterisation were used for the validation of the 1D model. Performance maps of modules with variation of hot and cold side temperatures were calculated and the influence of geometries and aspect-ratios have been investigated under the consideration of contact resistances. Finally the choice of different module substrates is discussed. The simulation framework enables rapid design‑for‑TEG optimisation, guiding material selection, stack segmentation, and geometrical limitations for TE modules.