The effect of expanded graphite on the performance of paraffin phase change materials used in thermal energy storage

Abstract

Paraffin is the most commonly used phase change type of material for thermal energy storage but the main drawback is it has very low thermal conductivity. This study aims to enhance the thermal conductivity of the base PCM through the use of expanded graphite as supporting material. The expanded graphite at different percentage 3wt%, 6wt%, 9wt%, 12wt%, 15wt% is mixed with paraffin and five samples are prepared. Experimental results obtained on the samples clearly show that the thermal properties of samples are improved when compare to that of pure paraffin. It is found that both thermal conductivity and thermal diffusivity are increasing rapidly. Melting temperature is standard there is no change for all the compositions. Specific heat gradually started increasing during the initial time and then it started decreasing as the expanded graphite percentage increased. The latent heat value of this composition has decreased a lot when compared to pure paraffin.