Assessment of long time approximation equation to determine thermal conductivity of high porous materials with NSS probe

Authors : Hussein HUMAİSH, Bastien RUET, Laurent MARMORET, Hassen BEJİ

Pages : 1-15

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Publication Date : 2016-05-23

Article Type : Research Paper

Abstract :Recent economic changes have increased the focus on energy conservation in buildings. Improve insulation represents one of the biggest challenge to save energy. The TP02 Huksefux® Non Steady State Probe insert ignore into journalissuearticles values(NSSP); has been used to determine the thermal conductivity of the building insulation materials. Usually, the long term approximation equation insert ignore into journalissuearticles values(linear form); is applied to determine the thermal conductivity when using hot wire techniques. Long term approximation has been successfully used to characterize glycerol: a fluid which doesn’t present contact resistance and porosity. But, an S-shaped appears for more porous materials. So to generalize the possibility of using this method, glass beads of 2, 8 and 10 mm balls diameters have been tested before characterising insulation materials. Firstly, we define the best portions in time insert ignore into journalissuearticles values(t 1 and t 2 ); of the S-shaped curve to determine thermal conductivity. Secondly, Comsol Multiphysics® test the influence of parameters of the TP02 Huksefux® like components of the probe, the contact resistance and electrical power on the S-shaped form.
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