Thermal energy storages analysis for high temperature in air solar systems

In this paper a high temperature thermal storage in a honeycomb solid matrix is numerically investigated and a parametric analysis is accomplished. In the formulation of the model it is assumed that the system geometry is cylindrical, the fluid and the solid thermophysical properties are temperature independent and radiative heat transfer is take into account whereas the effect of gravity are neglected. Air is employed as the working fluid and the solid material is cordierite. The evaluation of the fluid and thermal behaviors are accomplished assuming the honeycomb as a porous medium. The Brinkman- Forchheimer-extended Darcy model is used in the governing equations and the local thermal non equilibrium is assumed. The commercial CFD Fluent code is used to solve the governing equations in transient regime. Numerical simulations are carried out with storage medium at different mass flow rates of the working fluid and different porosity values. Results show the effects of storage medium, different porosity values, porosity effect and mass flow rate on stored thermal energy and storage time. Results in terms of temperature profiles and stored thermal energy as function of time are presented.