Abstract: Paraffin wax based phase change material (PCM) has a low thermal conductivity, which may significantly affect the heat transfer and solidification rates. Simulations are carried out to investigate the solidification behavior of a paraffin based thermal storage device containing graphite foam. The results show a more even temperature distribution and a significantly reduced solidification time due to the use of the high thermal conductivity graphite foam. Analyses are performed on the influence of fluid operating conditions including inlet temperature and velocity, on the solidification process of the paraffin/graphite foam. The results demonstrate that the solidification time decreases with increasing the inlet velocity and/or reducing the temperature of cooling water. Moreover, it is found that natural convection of the PCM can accelerate the solidification rate of the PCM.

Key words: graphite foam, solidification, phase change heat transfer enhancement, energy storage