Transient Analysis of an Improved Finned Tube Heat Exchanger for Thermal Energy Storage System

The melting and solidification process of sodium nitrate, which is used as energy storage material, is studied in a vertical arranged energy storage device with two different bimetal finned tube designs (with and without transversal fins) for enhancing the heat transfer. The finned tube design consists of a plain steel tube while the material for the longitudinal (axial) fins is aluminum. The investigation analyses the influence of the transversal fins on the charging and discharging process. 3-dimensional transient numerical simulations are performed using the ANSYS Fluent 14.5 software. The results show that every obstruction given by transversal fins reduces the melting and solidification velocity in direction to the outer shell. In the present study also a comparison of the simulation results between 2D and 3D simulation of the melting and solidification behavior of the sodium nitrate is presented.