An ideal nano-porous insulation material: Design, modeling and numerical validation

Based on the mechanisms of conductive heat transfer in nano-porous insulation materials, such as suppressed gaseous heat conduction at micro- and nanoscale, and low volume fraction of solid, a nano-porous material of hollow spherical pellets packing stack is designed. Its effective thermal conductivity is derived based on one-dimensional steady-state heat conduction, which is validated and improved by numerical simulation. Analysis on geometrical parameters, thermodynamic parameters and solid thermal conductivity indicates that the designed nano-porous material has the excellent thermal insulation performance. Decreasing the spherical shell thickness and the contact area can efficiently lower the effective thermal conductivity of material. Conductive heat transfer trough solid spherical shell has significant impact on the effective thermal conductivity of material. Under the same conditions, hollow spheres packed in line has the lowest effective thermal conductivity of about 0.01 W m−1 K−1, if properly designed.