The phase change materials can collect fluctuant solar energy and other low-grade energy to form a stable energy source for building insulation and the terminal equipment of the buildings. In this study

lauric acid and stearic acid were selected as the basic phase change materials. The binary equilibrium phase diagram was completed based on the step cooling curve method according to experimental tests data. The results showed that the phase transition temperature of the mixed acid at the lowest eutectic point was 31.2 ℃

and the latent heat value was 264.3 kJ/kg when the mixing ratio was 70% for lauric acid and 30% for stearic acid. Secondly

in order to improve the thermal stability and thermal conductivity of the mixed acid

silicon dioxide with a three-dimensional network structure was added to the mixed acid. The experimental results showed that when the proportion of the silicon dioxide in the hybrid materials was 35%

the mixed acid could be completely wrapped up by tetrahedral silica to form a stable phase unit change. Multiple cyclic experiments showed that the phase transition temperature of the hybrid phase change material was 30.8 ℃ and its latent heat value was 104.1 kJ/kg. Although the latent heat decreased

the thermal stability was greatly enhanced.