Preparation and properties of CaCl2·6H2O/silica aerogel composite phase change material for building energy conservation

To meet the national demand for energy conservation and emission reduction, a shape-stable CaCl2·6H2O /silica aerogel composite phase change material (CPCM) for building energy storage was successfully developed. The CPCM was formed by using modified CaCl2·6H2O composed of CaCl2·6H2O (main PCM) and SrCl2·6H2O (nucleating agent) as PCM, and silica aerogel as carrier via physical blending method. The structure and properties of the CPCM were investigated by various techniques. The results showed that compositing of modified CaCl2·6H2O with silica aerogel could significantly reduce the thermal conductivity, effectively prevent leakage as well as lessen supercooling. The obtained CPCM with 75 wt% modified CaCl2·6H2O had suitable phase transition temperature (27.0 °C) with high latent heat (110.9 J·g−1), acceptable supercooling degree (1.6 °C), low thermal conductivity (0.1954 W/(m·K)) as well as excellent thermal reliability. The results obtained make the CPCM in this work promising for use in building thermal insulation materials.