Preparation and thermal properties of sodium carbonate decahydrate as a novel phase change material for energy storage

In Photovoltaic (PV) cooling systems, the use of phase change materials (PCMs) to control temperature is crucial, especially for low-cost the materials with high latent heat. Sodium carbonate decahydrate (SCD) may a suitable candidate material, but its properties need to be modified. In this study, differential scanning calorimeter (DSC), scanning electron microscope (SEM), and hot disk were utilized to characterize the properties of the modified materials. It was observed that xanthan gum (GX) effectively prevents phase separation. Sodium pyrophosphate decahydrate (TPD), anhydrous sodium carbonate (ASC), and strontium chloride hexahydrate (SCH) are used as effective nucleating agents, However, after adding these agents, the latent heat of the system is significantly reduced, For example, in the SCD, GX, and TPD (SGT) system, the supercooling degree can be maintained at 5.2°C, the phase transition temperature is 33.3°C, and the latent heat of phase change is 193.3 J/g. Additionally, research has shown that super absorbent resin 20 mesh (SAP-20) possesses a porous three-dimensional network structure. Its non-ionic hydrophilic group forms stable intermolecular hydrogen bonds with water molecules, effectively preventing the loss of crystal water in hydrated salts. When a 5 % mass fraction (mt) of SAP-20 is added, it prevents SGT from leaking, and increases the phase change temperature and latent heat of fusion by 20.42 % and 19.61 %, respectively. These findings suggest that the composite material of 5 % mt SAP-20/SGT is an excellent candidate for PV cooling systems.