Prediction and Optimization of Thermal Conductivity of Vacuum Insulation Panels with Aerogel Composite Cores

As a type of thermal insulations with ultralow thermal conductivity, vacuum insulation panels (VIPs) have already been extensively applied in the field of insulating refrigerators, cold storages and building envelopes. However, their thermal conductivities increase rapidly with the increase of the gas pressure. To obtain a long-term low thermal conductivity, a vacuum insulation panel with fiber felt/silica aerogel composite core was proposed. A theoretical model was built and experimentally validated to effectively predict the conductivity of VIPs. The effects of the aerogel density (50~150 kg•m-3) and the fiber content (0~20 vol.%) on the thermal conductivity were investigated and optimized. The results indicated that the minimum thermal conductivity could be obtained via optimizing the fiber content. A low thermal conductivity less than 11.5 mW•m-1•K-1 could be obtained at internal pressures of 0~0.5 atm, which attributed to the nano and meso pore structure of aerogel composites. The optimization results provide guidance for the structure design and properties optimization of vacuum insulation panels with aerogel composite cores and consequently for promoting their applications in building thermal insulation for energy efficiency.