Design of microcombustor–thermoelectric coupled device using a CFD-based multiphysics model for power generation

Abstract

Catalytic combustion in micro-reactors can be coupled with thermoelectric power generator (TEG) modules for distributed and portable power generation, especially in niche applications. The efficiency of such an integrated device can be improved by operating the microcombustor at lean flow rates or using more efficient heat sinks. However, these lead to incomplete fuel conversion and eventually extinction instability. In contrast, high flow rates are detrimental to the TEG module owing to high temperatures. In this work, the TEG modules are coupled with a more efficient symmetric heat recirculating reactor (S-HRR) and a water-cooled heat sink to address this tradeoff between combustion stability and electrical efficiency. Specifically, we provide a detailed analysis of power generation from the integrated device and the impact of design parameters of the inner wall material and flue gas recirculation channel gap-size. We also present operating parameters for stable operation, based on combustion extinction limits and maximum operating temperature limitation of the TEG module and finally make a comparison of energy associated with various streams in the integrated device.