Experimental and numerical characterization of thermal bridges in prefabricated building walls

This work is a contribution to the characterization of the thermal efficiency of complex walls of buildings with respect to the ever increasing requirements in thermal insulation. The work specifically concerns the quantitative evaluation of heat losses by thermal bridges. The support of the study is the envelope of industrial light construction walls containing a metal framework, an insulating material inserted in between metal trusses, water and vapor barriers, and the internal and external facings. This article presents first the infrared thermography method which is used to visualize the thermal bridges as well as a genuine complementary experimental method allowing for the determination of the quantitative aspects of the heat losses through the envelope. Tangential-gradient heat fluxmeters, which create little disturbance in the measurements, are used in the context of laboratory and in full-scale insitu experiments. Then, the article presents a simple yet accurate prediction with a three-dimensional numerical method that could be used for the design of specific installations and parametric studies.