Experimental study on ethylene glycol/choline chloride deep eutectic solvent system based nanofluids

With the continuing development in the electric industry, highly efficient heat dissipation is of great significance due to the shrinkage of electric elements and increase in energy input. Working fluid, acting as a heat transfer medium, plays a core role in the thermal management. While, traditionally used working fluids suffer from either low thermal conductivity or relatively narrow liquid range that are unable to meet the growing demands for highly efficient thermal management. In this work, a silica decorated graphene (SDG) was fabricated using a sol-gel method and dispersed in a deep eutectic solvent (DES) system with the aim at addressing the poor thermal conductivity, stability and narrow working temperature range simultaneously. It is verified that the stability of nanofluids can be significantly improved since it could be kept for one week without obvious precipitation and aggregation due to the presence of silica coating on the layer of graphene. On the other hand, an 11.26% thermal conductivity enhancement was obtained by filling only 3.0  wt. % of the SDG. Moreover, viscosity study reveals that the presence of SDG has a slight influence on the rheological property of the nanofluids.