The global objective of this paper is to study the incorporation of phase change materials (PCM) into passive solar construction and other applications for the storage and stability of thermal energy. The PCM used is the n-octadecane and Gallium confined in a spherical capsule with normal and hollow fins. CFD numerical simulations have been carried out to increase the heat exchange area and to compare the effect of the regular fin with hollow one at different angles. The temperature changes inside the spherical capsule on the horizontal and vertical lines for a deep understanding of the PCM behavior are also realized. The results show that the melting time is reduced 14 times in the case of PCM with hollow fin compared to a configuration without fins.
