Effect of nanomaterial addition on the thermophysical properties of Iraqi paraffin wax

The storage and transfer speed of heat have become important topics in modern applications, particularly photovoltaic thermal (PV/T) applications. One of the latest developments in this field is the use of phase-change materials because of their ability to store thermal energy in the form of latent heat. The disadvantage of these substances is their low thermal conductivity, which hinders their widespread use. In this study, nano-Al2O3, nano-ZnO2 and nano-SiC were added to Iraqi paraffin wax. Changes in thermophysical properties were evaluated to determine the best materials for future PV/T applications. Results showed that the addition of any of the studied nanoparticles increased product density and viscosity. The addition of 5% nano-Al2O, nano-ZnO2 and nano-SiC increased wax density by 6.5%, 6.84% and 5.8%, respectively, and increased paraffin viscosity by 10.2%, 9% and 4.5%, respectively. Thermal conductivity improved by 3.3%, 1.8% and 4.2% with the addition of 1% nano-Al2O, nano-ZnO2 and nano-SiC, respectively. However, results indicated that thermal capacity was dependent on the additive's thermal conductivity, and its increase rate was limited. The paraffin synthesised with nano-SiC had the highest relative thermal conductivity and capacity (0.12 at 1% mass fraction). Nano-SiC paraffin presented the best results, whereas nano-ZnO2 paraffin showed the worst. Therefore, the addition of nano-SiC to Iraqi paraffin wax was the best option amongst the other studied options. The optimal addition mass fraction of Nano-SiC was approximately 1% and improved thermal properties with a limited increase in density and viscosity.