Numerical modelling of high temperature latent heat storage

Abstract

Numerical tools are widely used to optimize designs of latent heat storage systems as well as to control their operative conditions and control strategies. Within this context, the aim of the authors is to compare the performance of the different available numerical methodologies, which are used to model the phase change processes occurring in a high temperature heat storage system. The models are based on different types of discretization, use different methodologies to approach the phase change, and are implemented in different software platforms. Moreover, the numerical results are compared against experimental data from a test facility consisting of a flat plate latent heat storage tank with a measured PCM melting temperature at 219.5°C. The comparison of the different numerical methodologies presented in this research does not only focus on the agreement against experimental data, but on the computational cost, speed and convergence performance, as well. The results indicated that all four models provide good agreement in comparison to the experimental results. However, they differ significantly regarding convergence behavior. While a C-based model is recommended for simulation models with a small number of elements and small time steps, the models implemented in MATLAB perform better for simulation models with a high number of elements and large time steps.