This work is a part of a project aimed to develop low-cost utility scale thermal storage consisting of vertically placed cylindrical PCM capsules for next-generation power plants. This paper focuses on the energy transport mechanism during the phase change process. In this study an experiment was designed and constructed to investigate the charging and discharging in a vertical cylinder with enhanced radiative absorption. Charging and discharging was done in a tube furnace and time variant boundary conditions were used to negate the furnace regularities. A CFD model using the enthalpy-porosity method was created and validated based on the experimental data. The behavior of liquid fraction with the inclusion of radiation absorbing particles was analyzed. The usual present melting/solidification front was replaced by a much wider melting zone as a result of radiation absorbing particles.