Modeling Microstructure Effect on Thermal Conductivity of Aerogel-Based Vacuum Insulation Panels

Abstract

Understanding the effects of microstructural parameters on the heat transfer through an aerogel-based vacuum insulation panel (VIP) is important for the design and development of thermal insulation materials. The present work first prepared the aerogel-based VIP and characterize its microstructure through scanning electron microscopy and nitrogen gas adsorption analysis. A theoretical model for the thermal conductivity of the aerogel-based VIP was then presented and validated with experimental results. Based on the model, the effects of microstructural parameters, i.e. particle diameter and pore diameter, on the thermal conductivity of the aerogel-based VIP were explored. The results indicated an extremely low thermal conductivity with approximately 1.7?×?10^?3 W·m^?1·K^?1 can be achieved as the particle diameter and pore diameter are 1 and 10–15?nm, respectively. Furthermore, the microstructure effect under various service time of the aerogel-based VIP was considered for practical heat transfer engineering. It was found that the increase rate of the thermal conductivity decreases with a decreased particle diameter or an increased pore diameter. The microstructure effect modeling of the aerogel-based VIP could be of great advantage to heat transfer engineering applications aiming to reducing heat loss and saving energy.