A non destructive method for diagnosis of insulated building walls using infrared thermography in real situation

摘要

In order to provide a method to control conformity of insulation of buildings after restoration, Protomeres project waslaunched under Prebat 2005 program. This work deals with the development of an experimental protocol for thediagnostic of multi-layered insulated building walls. In a previous study, a test bench was set up in order to measure frontand back side temperatures of standard panels compounded of 1cm of plaster and various thicknesses of polystyrene. Thepanels considered have insulation thicknesses of 2, 6 and 10cm. In the present work, the panels are fixed on walls inlaboratory to test real situations in constructions. The front side is painted in standardized black color and heated by twohalogen lamps of 500W. A CEDIP Jade Long wave infrared camera and thermocouples are used to carry out temperaturemeasurements during an exposure time and subsequent cooling. In a second time, a one dimensional model based onthermal quadruples and Laplace transforms was developed under Matlab environment. This model simulates a three-layered wall with a blade of air between polystyrene and concrete. Finally, a method of identification of physicalparameters is implemented by performing least square minimization based on Levenberg-Marquardt method. Theexperimental measurements are compared to theoretical results and by minimization we obtain thermal conductivity anddiffusivity as well as thickness of the two layers.