Formulation of Nanostructured SiO2/D-Limonene Heat Transfer Fluids

Nanofluids, comprising nano-sized particles dispersed in a continuous base fluid, have drawn the attention of the scientific community owing to their remarkable thermophysical properties. These advanced materials have been proven to exhibit highly versatile tunability via the modification of some formulating parameters, such as size, shape, and content of the nanoparticles, as well as through the base fluid properties. Among the variety of existing nanoparticles, surface-modified silica nanoparticles stand out owing to their high availability, low cost, sustainability, and stability. Additionally, D-Limonene has been considered as the base fluid given its significant availability, lack of toxicity, and antimicrobial characteristics, as well as its significantly low viscosity, hence minimizing the pumping energy requirements. In this research, silica nanoparticles were incorporated (0–5%) into D-Limonene and their rheological and thermophysical properties were analysed to evaluate their potential application as heat transfer nanofluids in the cold industry. Despite the viscosity and thermal stability enhancement caused by the addition of silica nanoparticles into D-Limonene, at the expense of their thermal conductivity, formulated nanostructure fluids have been proven to properly flow under shear conditions within the temperature range from −25 up to 25 ºC, hence corroborating their potential application as heat-transfer fluids under steady shear conditions.