Numerical investigation of the melting temperature effect on the performance of thermocline thermal energy storage tank for CSP

The current paper presents parametric study to evaluate the effect of the melting temperature on the performance of multi-layered solid-PCM (MLSPCM) thermocline tank for concentrated solar power plants (CSP) applications. The model is developed using the Concentric-Dispersion (C-D) equations. The results obtained are validated against the experimental data from the literature. The governing equations are solved in MATLAB using finite difference method. The results show that an optimal three-layer cascaded thermocline tank should include a top PCM layer that has a dimensionless temperature (theta) equal to 0.8, a middle PCM layer that has a dimensionless temperature (theta) equal to 0.5, and a bottom PCM layer that has a dimensionless temperature (theta) equal to 0.35. Moreover, the results show that an optimal three-layer cascaded latent heat thermocline tank should include a top PCM layer that melts slightly above the molten salt hot supply threshold and a bottom PCM layer that melts slightly below the cold return threshold. (C) 2019 The Authors. Published by Elsevier Ltd.