Applications of heat transfer and fluid flow through porous media are very capacious, so they have drawn great attention and research. Acoustics, filtrations, and heat storage are examples of the wide application. The technique of the thermal energy storage (TES) to stock heat energy for later use is applied in many applications. Reliable stable low cost can be provided by storage solar thermal energy and undue heat from non-natural sources. A simple low-cost design that can fluently be constructed which uses the available porous media founded in nature is considered in the present study. The present study analytically investigated the effect of faction void of porous media (silicon rubber) on the process of heat transfer through heat storage and on the storage system. The study develops a numerical model to investigate the effect of several parameters, e.g. mass flow rate, bed length, particle diameter and different values of porosity during charging and discharge. The results depict that the amount of thermal energy stored, and the time of storage are affected by the working fluid, its porosity, and mass flow rate. The present model uses water as working fluid and the silicon rubber as storage medium. It is governed by two partial differential equations for these two substances. The conservation equations are applied on the present system for each of them separately. The storage medium and the working fluid are in case of heat exchange process all over.