Numerical simulation on thermal energy storage behavior of Cu-H2O nanofluids

The cold storage of nanofluids as the phase material in a two-dimensional enclosure was numerically simulated with Fluent software. The effect of copper particle concentration and Grashof number on cold storage properties was investigated. The results indicate that the cold storage properties exhibit little sensitivity to Grashof number, but the volume fraction of the nanoparticle is main effective factor on the cold storage properties. For a given initial Grashof number, as the solid particle volume fraction is raised the freezing time is lowered. Adding 1.0% Cu nanoparticles into pure water, the total freezing time can be saved by 16.3%. This is due to the enhanced thermal conductivity of the nanofluid in comparison to that of the base liquid. At the same time, due to lowering of the latent heat of fusion, less energy per unit mass of the nanofluid is needed for freezing the nanofluids. The observed higher heat release rate of the nanofluids is a clear indicator of its great potential for thermal energy storage applications.