This work evaluates numerically using Ansys (fluent) CFD software the effective radiative parameter ( ) of a volumetric solar absorber module of honeycomb structure (HiTRec II). For that purpose, a single channel of the HiTRec module is investigated, as the effective parameter recovered from it can represent the radiative behaviour of the complete structure. The radiative parameter presented in this work is of major importance because it predicts the volumetric energy absorption along the transversal direction of the channel and as consequence, the thermal efficiency and the temperature...