Thermophysical properties of nanoparticle-enhanced deep eutectic solvents (NEDESs) heat-transfer fluids

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Deep eutectic solvents (DESs) are a new class of promising green media and considered as a versatile alternative to conventional ionic liquids (ILs), since DESs share most of the excellent physic-chemical properties of traditionally used ILs, but overcome the toxicity and high cost of ILs. A DES is generally formed from two or three safe and cheap components through hydrogen bond interactions and obtain a eutectic mixture with a melting point lower than that of each individual component. Nanofluids are a new class of fluids produced by dispersing nanoparticles in a base fluid and considered as potential heat-transfer fluids due to their ability to increase the thermal conductivity of base fluids. In this context, the potential application of DESs as base solvents of nanofluids was studied in this research. Experimental investigations were completed on SiO2 nanoparticles, graphene nanoplatelets and Al2O3 nanowires enhanced DESs (NEDESs) heat-transfer fluids as an alternative to conventional heat-transfer fluids. ChCl/urea, ChCl/EG and ChCl/glycerol DESs with different salt/HBD molar ratios were selected as the base fluid. NEDESs associated with graphene nanoplatelets were found to have the largest thermal conductivity temperature dependence. The effects of different DES systems, different salt/HBD molar ratios and loading percentage of SiO2 nanoparticles on thermalphysical properties were discussed.