Thermal Conductivity Enhancement Phenomena in Ionic Liquid – Based Nanofluids (Ionanofluids)

The dispersion of nanoparticles into ionic liquids leads to enhancement of their thermal conductivity. Several literature papers report on various enhancement values, whereas the comparison between these values with those from theoretical calculations is not always performed. These thermal conductivity enhancements are desired due to their beneficial impact on the heat transfer performance in a process requesting the utilization of heat transfer fluids. Moreover, on the one hand, the theoretical modelling of these enhancements might lead to an easier, cheaper and faster heat transfer unit design, which could be an enormous advantage in the design of novel industrial applications. On the other hand, it gives a significant impact onto the enhancement mechanism. The aim of this work is to discuss the enhancement of thermal conductivity caused by the dispersion of nanoparticles in ionic liquids, including the analysis of their errors, followed by its theoretical modelling. Furthermore, a comparison between data reported, herein, with those available in the literature is carried out with following reproducibility of thermal conductivity statement. The ionic liquids studied are the 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-hexyl-3-methylimidazolium hexafluorophosphate, while carbon nanotubes, boron nitride and graphite were selected as nanoparticles to be dispersed in investigated ILs to design novel heat transfer fluids.