Dehydration of salt hydrates, being an endothermic process, helps in the storage of solar energy which can then be regenerated for future use by simply hydrating the salts. During dehydration, the crystal structure changes significantly. In order to study these changes as well as to study the performance of dehydration, a number of molecular dynamic simulations is carried out for two salt hydrates (MgSO4 and ZnSO4 hepta hydrates). All simulations were performed using LAMMPS package with universal force field. Dehydration is performed at varying temperatures and pressures. The variation in the kinetics of dehydration between ZnSO4 and MgSO4 is analysed by computing the rate of water molecules leaving the crystal.