Paraffin wax with an addition of nano Ti2O3: Improve thermal and photothermal performances with little decreased latent heat

Abstract

Organic phase change material (PCM) has gathered considerable interest in various fields, especially in solar photothermal conversion. Nanoparticles were often utilized to improve the photothermal and thermal performances of PCM. In this work, the nano-scaled particles are obtained by grinding coarse Ti2O3 powder, then they have been successfully dispersed into paraffin wax with various mass fractions. The thermal and photothermal performances get an experimental evaluation. The results indicate that the latent heat is decreased with the mass fraction, while the photothermal conversion efficiency gets improvement with the mass fraction. The 9 % mass fraction gives the highest thermal conductivity with an improvement of 37.8 % and the photothermal conversion efficiency is about 80 %. Besides, these improvements are accompanied by a mere 5.3 % drop in latent heat, much lower than the mass fraction of nanoparticles. Nano Ti2O3 is first reported as an ideal particle for photothermal conversion of PCM, and it is suggested that the mass fraction should be less than 30 %.