CA-LA eutectic/nano-SiO2 composite phase change material for building thermal energy conservation

A kind of form-stable phase change material (PCM) based on capric-lauric acid eutectic acting as the heat-absorbing material and nano silicon dioxide serving as the supportive material was prepared by sol-gel method. The optimal proportion of the capric-lauric acid eutectic in the composite was determined as 60 wt. %. By the effect of capillarity and hydrogen bonding, fatty acid eutectic can be immobilized in the three-dimensional network structure constructed by the bond of Si and O atoms thus the composite remained solid when the sample was heated above the melted point of the fatty acid eutectic. The morphology and chemical characterization of the composite PCM were investigated by transmission electron microscope, scanning electron microscopy, and Fourier-transform infrared method. Differential scanning calorimetry was used to measure the phase change temperature and latent heat of the composite, and the values were 19.57°C and 71.28 J/g, respectively. Meanwhile, service performance of the composite such as thermal stability and thermal conductivity were also examined using thermogravimetric analysis and transient hot-wire method, respectively.