Investigating the effect of external heat flux and atomic structure on the thermal behavior and phase change process of sodium sulfate/magnesium chloride hexahydrate and paraffin with molecular dynamics simulation

Phase change materials (PCMs) are capable of thermal energy storage since they have a set melting point and a high latent heat of melting. PCMs offer up to 15 times the heat capacity per unit volume compared to conventional storage materials. The results show that laboratory methods were expensive and time-consuming. Therefore, using the molecular dynamics (MD) simulation method, this study investigated the effect of external heat flux (EHF) (0.001-0.005 W m-2) and structural type (paraffin (S2) and sodium sulfate/magnesium chloride hexahydrate (S1)) on the thermal behavior (TB) and phase change process (PCP). The effect of these two factors was investigated on the temperature profile, heat flux (HF), charge, and discharge times. The results showed that the thermal and atomic properties of S1 are better than S2. As a result, the composite of two PCMs improves the properties. Due to its performance and safety, it can be used in industries. On the other hand, the EHF in S1 increases the HF, temperature, charge, and discharge time.