Thermal properties evaluation of paraffin wax enhanced with carbon nanotubes as latent heat thermal energy storage

An efficient phase change material (PCM) should not only exhibit high latent heat, but also high thermal conductivity. Combination of these favourable properties leads to an efficient latent heat thermal energy storage. Paraffin wax is one of the popular options for organic PCMs. However, paraffin wax has a low thermal conductivity, hindering its heat charging and discharging process. This study explores the effect of multi-walled carbon nanotube (MWCNT) weight percentage (0–0.08 wt%) and various surfactants (gum arabic (GA), polyvinylpyrrolidone (PVP), sodium docecylbenzene sulfonate (SDBS), and sodium dodecyl sulfate (SDS)) on the thermal conductivity, melting temperature, melting latent heat and thermal stability of paraffin wax. It is found that the maximum thermal conductivity enhancement (48%) is exhibited by paraffin wax/0.06 wt% MWCNT without surfactant compared to paraffin wax. The thermal conductivity of paraffin wax/0.08 wt% MWCNT added with PVP, SDBS and SDS are higher than samples added with GA. Overall, all samples exhibit single-step decomposition characteristics, as shown in thermogravimetric analysis (TGA).