Heat Transfer Behaviours of Parallel Squared Channel Systems for Latent Heat Thermal Energy Storage

In the present work a computational investigation of transient thermal control device using Phase Change Material (PCM) is accomplished. The system is a honeycomb solid checkerboard matrix filled with Phase Change Material. The honeycomb is set of different parallel squared channels and half of them are filled with PCM and the others are passed through by the working fluid. Various configurations are investigated for different channels per unit of length (CPL), different heat fluxes and inlet velocities. A comparison between the direct honeycomb model and a porous medium model is made. The porous medium is modelled with the extended Darcy-Brinkman law and to evaluate the heat exchange between the solid and the fluid zones a Local-Thermal Non-Equilibrium assumption is used. By the results of the direct honeycomb model the characteristics such as permeability, inertial resistant coefficient, effective thermal conductivity and interfacial heat transfer are evaluated and then compare with the porous medium model. The analysis have the aim of estimate an optimized configuration in term of channels per unit of length (CPL) as a balance between pressure drop and heat transfer rate inside the honeycomb system. Numerical simulations were carried out using the Ansys-Fluent 15.0 code. Results in terms of melting time, temperature fields, stored energy as function of time are presented for the charging and discharging phase.