Abstract
Nanofluids are utilized in cooling equipment such as heat exchangers and renewable energies such as solar cells as heat transfer fluid. The techniques for nanofluid stability enhancement and stability evaluations, such as zeta potential, electron microscopy, and photographic techniques for sedimentation, are reviewed as well as some recent achievements in nanofluid stabilization and research on the parameters affecting the thermal properties of nanofluids. Finally, the applications of nanofluids in cooling devices are described. Increased heat transfer, reduced heat transfer time and size of heat exchangers, and finally higher energy and heat efficiency could be the most significant achievements. The parameters affecting the thermal conductivity of nanofluids include concentration, temperature, particle fluid, type of base fluid, and nanoparticles.