A predictive model for describing the gas enthalpy-radiation conversion process in an open-cellular porous plate is proposed. The ability of the model in predicting temperature distributions within porous converters is examined in comparison with available experimental data. Extensive numerical simulations for commercially available porous plates made of Ni-Cr and partially-stabilized ZrO₂ are performed by varying several system parameters such as porous plate thickness, inlet gas temperature and mass flow rate in order to evaluate decreases in gas temperature across the porous plates and the conversion efficiency defined by a ratio of recaptured radiation to incoming energy and also to give design tips on this kind of porous converter.