Development and reliability assessment of nano-enhanced novel organic eutectic mixtures as phase change materials for latent heat energy storage

From the huge unexplored potential of non-paraffin organic compounds with exceptional thermal energy storage characteristics, this study identifies two novel eutectic PCM of margaric acid–behenic acid (MB) and palmitic acid–behenic acid (PB) with a melting temperature of 62.47 °C and 62.62 °C with high melting enthalpies of 170.66 J g^-1 and 188.86 J g^-1, respectively. To analyse the effects of nano-enhancement and with an objective of improved thermophysical characteristics, multi-walled carbon nanotubes were added over varying concentrations (0.5%, 1% and 1.5% of mass). Initial thermal conductivities of 0.134 W m^-1 K^-1 and 0.138 W m^-1 K^-1 were improved with the addition of nanoparticles to 0.312 W m^-1 K^-1 and 0.305 W m^-1 K^-1, reporting a 132.8% and 122.46% for MB and PB eutectic mixtures, respectively. Contrary to the usual trend, a highly significant and advantageous increment in melting enthalpy was also observed for both MB and PB eutectic mixtures by 21.9% and 15.8%, respectively. Further, the chemical stability, optical characteristics and thermal stability of the eutectic mixtures were analysed to ensure compatibility towards thermal energy storage applications.