Experimental determination of thermal properties of brick wall for existing construction in the north of France

Old houses (before 1948) in Northern Europe have a lot of architectural similarities and one of the most common relates to thick brick walls. The study of thermal transfer in old massive walls provides a better understanding of their thermal behavior and to quantify the savings of energy following a possible thermal insulation. The specificity of these walls resides in the fact that their materials were manufactured in a period when the thermal standards were non-existent and therefore their thermal properties are not precisely known. This paper presents two experimental approaches for determining the thermal properties of masonry walls. In the first method, the materials composing the wall were characterized separately and then equivalent thermal resistance and thermal capacity were deduced; in the second one thermal transfer in an experimental wall was studied by imposing thermal conditions from one side of the wall through a heating box, the other side remaining exposed to ambient lab thermal conditions. The experimental wall is exposed to two different types of boundary conditions through a wooden insulated box which contains a radiator: the constant temperature (steady state mode) to determine the thermal resistances of the system and the sinusoidal temperature (harmonic mode) to determine the thermal capacity of the wall.