Experimental study of the thermal behaviour of nano-enhanced phase change materials (NPCMs)

Highly conductive particles have been used to improve the inherent thermal conductivity of phase change materials (PCMs). To investigate the heat transfer process of PCMs enhanced by nano-particles, the melting process of 15 kinds of nano-particles PCMs (NPCMs) was observed in test tubes with different nano-particles and particle concentrations. The NPCMs were prepared by dispersing nano-coconut shell charcoal with mass fraction ranged from 0.02 wt % to 18.5 wt.% and nano-graphite with mass fraction from 0.02 wt.% to 1.0 wt.% in paraffin-based PCM with a nominal melting temperature range of 26-28 °C. Type T thermocouples were used to monitor the temperature variation of each material under different boundary temperatures in a climate chamber. Thermovision tests were conducted to illustrate the temperature distribution. It was found that Nano-particles was able to enhance the heat transfer of PCMs. The addition of nanoparticles within 0.1 wt.% didn’t affect the phase change characteristics of paraffin.Dispersant was able to enhance the heat transfer of NPCMs. However, when the concentration increased to 18.5 wt.%, more particles were observed at the bottom of the test tubes, causing heat transfer dead zones.