Study of behaviour of thermal insulation materials under extremely low pressure

Brno University of Technology, Faculty of Civil Engineering, Veveří 331/95, 602 00 Brno, Czech Republic

^* Corresponding author: zach.j@fce.vutbr.cz

Abstract

In most thermal insulation materials, reduced internal pressure improves thermal insulation properties. It reduces heat transport by convection as well as heat conduction in gases in the material´s pore structure. The dependence of thermal conductivity on pressure is individual to every type of insulation with open porosity. In general, a material with fine porosity is not very sensitive to pressure change within the range of very low pressure to vacuum. On the other hand, materials with a larger number of bigger pores are more sensitive to changing pressure. Any pressure change between atmosphere pressure and vacuum causes a change in thermal conductivity. The paper presents the results of an investigation into the behaviour of alternative fibrous insulations usable in the production of vacuum insulation panels at low pressure.