Editors : S. Komarneni, J.C. Parker, H.J. Wollenberger
a1 Materials Science Division, Argonne National Laboratory, 9700 S.Cass Ave., Bldg. 212, Argonne, IL 60439 (JEastman@ANL.GOV)
a2 Materials Science Division, Argonne National Laboratory, 9700 S.Cass Ave., Bldg. 212, Argonne, IL 60439
a3 Energy Technology Division, Argonne National Laboratory, 9700 S.Cass Ave., Bldg. 212, Argonne, IL 60439
Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids required in many industrial applications. To overcome this limitation, a new class of heat transfer fluids is being developed by suspending nanocry stalline particles in liquids such as water or oil. The resulting “nanofluids” possess extremely high thermal conductivities compared to the liquids without dispersed nanocrystalline particles. For example, 5 volume % of nanocrystalline copper oxide particles suspended in water results in an improvement in thermal conductivity of almost 60% compared to water without nanoparticles. Excellent suspension properties are also observed, with no significant settling of nanocrystalline oxide particles occurring in stationary fluids over time periods longer than several days. Direct evaporation of Cu nano-particles into pump oil results in similar improvements in thermal conductivity compared to oxide-in-water systems, but importantly, requires far smaller concentrations of dispersed nanocrystalline powder.