Transient modeling of combined conduction and radiation in wood fibre insulation and comparison with experimental data

This is an innovative study of wood wool used for building insulation and the reported results could be important for improving the cooling and the heating efficiency of buildings. Wood fibre boards are non-grey, absorbing and scattering media. The radiative properties of the wood wool (albedo, optical thickness and phase function coefficients) were identified using an inverse method based on infrared experimental measurements of reflection and transmission. The radiative part was then found negligible with respect to the phonic part in steady state for the material tested. Transient one-dimensional coupled radiative and conductive heat transfer was solved in a wood wool material. The transient numerical results were validated by comparing them with fluxmeter measurements when temperatures were fixed at the boundaries. The temperatures and the heat capacity had strong influence on the transient numerical results. Finally, our computations showed that a purely conductive model gives the same fluxes at the boundary as the coupled radiative-conductive model.