Analyzing wood bark insulation board structure using X-ray computed tomography and modeling its thermal conductivity by means of finite difference method

Abstract

The continuous trend to energy saving and sustainable constructions in buildings leads to an increasing demand of efficient and sustainable thermal insulation materials. One promising development is the usage of the natural “tree insulation material,” namely bark, for building insulations. Insulation boards out of larch bark were scanned with an industrial computed tomograph in order to study the structure of the boards. The computed tomograph images were segmented using a categorization algorithm based on ANOVA. Apart from gaining knowledge about panel porosity, understanding of the inhomogeneous bark boards was enhanced by finding that two main components are prevalent. That knowledge of the board's microstructure enabled the application of a numerical model for thermal conductivity based on the finite difference method. These findings give the direction for further developments of efficient bark insulation panels with well-defined pore structure.