Synthesis and characterization of copper nanoparticles-embedded paraffin wax for solar energy storage.

Nano-sized high conductive particles are extensively used in many engineering applications to achieve enhanced thermal performance. Paraffin wax is regarded as the most promising phase change material (PCM) for energy storage applications. However, the low thermal conductivity of paraffin poses a challenge which decreases the performance of storage system. In this work, composite PCMs consisting of paraffin and copper (Cu) nanoparticles were synthesized at different mass percentages (0%, 0.5%, 1%, 2% and 3%) and the thermo-physical properties were examined experimentally. The field emission scanning electron microscope (FESEM) results showed that the dispersion of nanoparticles in the PCM is homogeneous. The differential scanning calorimeter reports revealed that the effect of nanoparticle addition on phase change temperature is insignificant. On the other hand, reduction in latent heat is observed. The addition of nanoparticles is found to be critical in prolonging the thermal degradation of the storage medium which ensures the thermal and chemical stability of nano-Cu–paraffin composites. Moreover, the thermal conductivity of solid PCM is enhanced by 7%, 14%, 24% and 30.5% with the nanoparticle loading of 0.5%, 1%, 2% and 3%, respectively. In case of liquid PCM, the enhancement is found to be 8%, 15%, 28% and 31.5% with mass fraction of 0.5%, 1%, 2% and 3%, respectively. Altogether, the obtained results have revealed that the enhanced properties make nano-Cu–paraffin composite PCM as right candidate for solar thermal energy storage. [ABSTRACT FROM AUTHOR]