Performance assessment of heat storage by phase change materials containing MWCNTs and graphite

This study reports the production of modified phase change materials (MPCMs) using the direct-synthesis method to mix paraffin with MWCNTs and graphite as the experimental sample. The MWCNTs and graphite were dispersed into three concentrations of 1.0, 2.0, and 3.0 wt.%. This study experimentally investigates the influences of the additive concentrations of the additives in the paraffin on their temperature and phase change heat variations by charging/discharging temperature difference and DSC experiments to evaluate the feasibility for thermal storage. Experimental results demonstrate that adding the MWCNTs was more effective than graphite in modifying the thermal storage performance of paraffin for most of the experimental parameters. Furthermore, adding MWCNTs reduced the melting onset temperature and increased the solidification onset temperature for paraffin. This makes the phase change heat applicable to a wider temperature range, and the highest decreased ratio of phase change heat was only 3.69%, compared with paraffin. This study demonstrates that for enhancing the thermal storage characteristic of PCMs by adding MWCNTs to paraffin to form MPCMs has great potential.