Inorganic salt hydrates as a phase change material have the advantage of high latent heat values, high thermal conductivity and are not flammable. Phase segregation is the key downside feature that restricts its application in thermal energy storage application. A PU-PCM composite was prepared by incorporating aqueous saturated sodium sulphate solution, inorganic phase change material (PCM), within open pores of polyurethane (PU) foam. Experimental study on the thermal insulation performance of this composite, aqueous sodium sulphate solution embedded in open cell polyurethane foam, was discussed. This paper presents the computational solving approach for the thermal analysis of this composite having crystallization of sodium sulphate decahydrate, from its aqueous solution, within open pores of PU foam. Thermal study of salt solution in a porous material that undergoes phase change was done using COMSOL Multiphysics software and results were compared with experimental result.