Performance-optimized optical-thermal coupling in high-flux solar simulator-porous media reactor system for high-temperature polygeneration

Solar-driven thermochemical polygeneration (e.g., heat, syngas, H₂) offers a sustainable pathway for converting solar energy into storable fuels and heat. However, its efficiency is constrained by heat transfer and reactor design limitations. This study develops an optical-thermal coupling framework for a high-flux solar simulator (HFSS) and reactor system featuring a radially configured porous cavity. Through finite volume simulations (FVM), the coupled effects of incident radiation power (1.5–7.5 kW), inlet gas flow rate (100–1000 sccm (standard cubic centimeters per minute, at 1 atm and 273.15 K)), and porous structure (10–30 PPI (pores per inch, a measure of pore density)) on thermal behavior are systematically analyzed. The results identify an optimal radiation power of 4.5 kW, which maximizes thermal efficiency while minimizing axial temperature gradients. A low flow rate of 100 sccm ensures uniform fluid heating (ΔT < 30 K), and a 10 PPI porous structure enhances radiative absorption uniformity and reduces flow resistance. In contrast, higher PPI values intensify radial temperature non-uniformity. The proposed design successfully balances radiation absorption with convective heat transfer, providing quantitative guidelines and theoretical insights for the optimization of high-performance solar-driven thermochemical reactors.