Modeling of Thermal Integration of a Catalytic Microcombustor with a Thermoelectric for Power Generation Applications

Abstract

Power generation from coupled devices employing combustion in microreactors is generating interest for portable or decentralized energy demands. We develop a model framework to predict the performance of an integrated catalytic microreactor–thermoelectric generator (TEG) device, using CFD. A strategy for modeling a standalone TEG module is proposed and validated first, followed by thermally integrating it with a microreactor. The concepts of 1D global energy conservation with lumped treatment of the electrical properties are used to develop the TEG model. Multiple thermocouples, consisting of p- and n-type semiconductors connected in series, are modeled as a single block. The properties of the Seebeck coefficient, internal resistance, and thermal conductance are aggregated for the entire block and estimated as polynomial functions of temperature. These parameters can be estimated from manufacturer data. The source terms for Seebeck, Peltier, Thomson, and Joule’s effects are incorporated into the energy conservation equation to model the TEG at steady state. The TEG model is validated with experiments in the literature. The catalytic combustion of hydrogen in a microreactor is validated independently and is subsequently used for modeling a catalytic microreactor integrated with a TEG module for power generation. The power extracted by various load resistances from the coupled device, at multiple values of inlet flow rates, is calculated and shows a good comparison with experimental data in the literature.