A Laser Flash device (NETZSCH, Nano Flash LFA447) was used to evaluate error in thermal diffusivity estimation using described methodology above. A polystyrene sample was measured. Figure 4 shows temperature evolution during the test and figure 5 compared results between Laser Flash and modified energy balance setup.

As it is shown in figure 5, results obtained with modified energy balances setup are less accurate, but big samples can be tested and thermal conductivity of the composed material can be evaluated. Nevertheless, LFA measurements are more accurate. For LFA measurements small samples (maximum 2 millimetres thickness) are required. These two experimental setups, LFA and modified energy balance setup are then complementary.

2. Conclusions

Using the experimental setup presented in this work previous analysis of transient thermal behaviour of building materials is done. It has special interest for those materials that is not possible to have small samples to test in more precise devices like Laser Flash. This methodology has promising results and work is going to continue in this field.

Nowadays, the most interesting application of this setup is to compare thermal response of building materials containing phase change materials and without containing.

Acknowledges

Authors would like to thank Spanish government for supporting this work done in the research project ENE2005-08256-C02-02/CON.

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