Optimized cold-end structure in a MTPV-MTEG utilization system: Analysis of combustion characteristics and energy efficiency

The micro-thermophotovoltaic (MTPV)-thermoelectric (MTEG) two-stage utilization system based on micro-combustor design demonstrates enhanced combustion stability and energy conversion efficiency. However, the thermal management constraints at the MTEG cold-end significantly limit the overall system performance improvement. To address this critical challenge, we proposed three novel heat dissipation architectures: plate fin structure, needle fin structure, and lattice structure. Through systematic numerical investigations, the thermal regulation effects of different configurations on temperature gradient formation and energy conversion characteristics were comprehensively evaluated. Remarkably, structural modifications at the cold-end exhibit negligible impacts on MTPV module performance and combustion chamber dynamics. The lattice structure demonstrates superior thermal dissipation capacity (150mm3 heat dissipation volume) coupled with exceptional mass-specific performance, achieving peak MTEG output of 3.94 W and elevating total system efficiency to 7.96 %. Furthermore, the optimized system extends the operational envelope to 16 m/s inlet velocity, delivering 21.89 W total power output (including 7.24 W from MTEG) while maintaining 6.75 % energy conversion efficiency. This work establishes fundamental design principles for advanced thermal management in micro-energy systems, providing critical insights for next-generation portable power devices development.