As a new generation of thermal insulation materials, the effective thermal conductivity of aerogel and its composites is extremely low. The nanoporous structure of aerogels demobilises the movement of gas molecules, and the nano-skeleton system restricts solid heat transfer because of the size effect. Numerous research and modelling works have been carried out to understand and predict heat transfers. This review thoroughly discusses the existing theories and models of silica aerogel composites in gas, solid and radiative heat transfers. It investigates the correlation of the pore size distribution and solid skeleton network of the composites with the thermal conductivity. The review then assesses the advances of the development and questions remaining for further development, including 1) some unexplainable performance of existing models and 2) improvements required for gas and solid thermal conductivity models. Bridging the identified research gaps shall lead researchers to understand existing models better, develop a more accurate model based on more realistic microstructure simulation and further innovate the models for other emerging composites.
|Journal of Building Engineering
|Early online date
|15 Jun 2022
|Published - 1 Oct 2022
Bibliographical note© 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license 4.0
The project leading to this paper has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 869898 .
- Aerogel composites
- Heat transfer
- Thermal conductivity