In this study, experiments are conducted to investigate charging and discharging characteristics of aparaffin as a phase change material (PCM). A vertical tube-in-shell geometry is designed to store the PCM. The thermophysical properties of the paraffin examined are determined through the differential scanning calorimeter (DSC) analysis. A series of experiments are carried out to investigate the effect of increasing the inlet temperature and the mass flow rate of the heat transfer fluid (HTF) both on the charging and discharging processes (i.e., melting and solidification) of the PCM.