A solar radiation absorber was simulated with CFD techniques and the results are compared with experimental data. The porous medium was modelled with a dispersed particle approach. Heat transfer of the porous media was calculated separately for a non-equilibrium approach. Radiative heat transfer plays an important role because all of the energy is received from the exterior by radiation. The radiation was modelled using the discrete ordinates model which seem to work properly in high participative media and presents a good directional accuracy. However, this method is not appropriated to simulate a multiphase medium where the temperatures and radiative properties of the different phases should be taken into account. Thus, a modification of the discrete ordinates method was introduced to consider the effect solid and gas phases. The results of the presented methodology were compared with other commonly used methods obtaining a reasonably better agreement with experimental data. (C) 2012 Elsevier Ltd. All rights reserved.