Parametric Analysis of PCM in Vertical Triplex Tube Thermal Energy Storage Technology for Concentrating Solar Power.

A numerical heat transfer analysis of the phase change material (PCM) in a high temperature vertical triplex tube thermal energy storage system (TTTESS) was performed, using ANSYS FLUENT 15.0. The model has been validated against experimental data using a low temperature PCM in a TTTESS. The numerical results agree well with experiment. The validated model was used to analyse a high temperature PCM in a TTTESS. Supercritical CO2 was assumed for the heat transfer fluid (HTF) which flows in the inside and outside tubes, whereas the lithium and potassium carbonate (Li2CO3-K2CO3) (35%-65%) PCM with a melting temperature of 505°C was enclosed between them. This study provides a comprehensive parametric analysis to demonstrate the effect of adding more fins relative to the case of no fins on the melting and solidification processes to find the optimum design of the TTTESS. The TTTESS with eight fins is the design that has substantial performance and is cost competitive compared with two-tank system [ABSTRACT FROM AUTHOR]