(275g) A Hydrated Salt/SiO2 Shape-Stabilized Phase Change Material Prepared Via Sol-Gel Process

The utilization of phase change materials (PCM), which can absorb, and release the latent heat over a defined temperature range while undergoing phase change, for thermal energy storage has received considerable attention. A novel shape-stabilized phase change material with a mixture of hydrated salts, Na₂SO₄•10H₂O-Na₂HPO₄•12H₂O as phase change material and SiO₂ as supporting material was prepared via sol-gel process in this work. In the composite, Na₂SO₄•10H₂O-Na₂HPO₄•12H₂O was embedded into the porous structure of SiO₂ and encapsulated by polyvinylpyrrolidone (PVP), so that there is no leakage of it during the solid-liquid phase change even when its maximum mass fraction reached 70wt%. The surface morphology was observed by scanning electron microscopy (SEM). Fourier transformation infrared (FT-IR) analysis was conducted to investigate the chemical compatibility between Na₂SO₄•10H₂O-Na₂HPO₄•12H₂O and SiO₂. Thermal properties, such as latent heats and phase change temperatures, and thermal stability of the composite PCMs were determined using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The DSC results showed that the melting temperatures and latent heat values of the composite PCMs are in range of 29-38°C and 41-89kJ/kg, respectively. The thermal cycling tests revealed that the composite PCMs had good thermal reliability and chemical stability.