Numerical and experimental thermal inertia characterization of an integrated insulation clay hollow block for buildings thermal comfort applications

Abstract

Integrated insulation clay hollow blocks present a complex geometry with 2 different materials: clay and mineral wool along high thickness (from 30 to 42,5 cm here) with integrated thermal bridges. The equivalent thermal conductivity λeqis often well known for energetic calculations but the equivalent density ρeqand heat capacity Cpeqare not assessed. The aim here is to propose a method to obtain the equivalent parameters linked to thermal inertia to be used in an energy building simulation tool, which always supposes uniform materials layers and 1D thermal transfers. This method is composed of a numerical phase and an experimental phase. At first, a 1D finite difference model has been created in order to simulate the thermal behavior of this kind of block. Then, an experimental test bench has been created based on two 1 m3climatic rooms and a 1 m2wall sample holder in order to calibrate the 1D model thanks to experimental data. An optimization procedure lets to identify the equivalent thermal properties of a uniform block which presents the same dynamic thermal behavior. Finally, a validation is carried out by comparing TRNSYS simulations and in situ experimental data in a dwelling building. The novelty of this work is to propose an original and complete approach on inertia properties characterization of a complex geometry of modern blocks by a complete procedure from a 1D mode, experimental tests, in situ tests and TRNSYS simulations. The main result show a low thermal capacity for all of these blocks in comparison with others construction materials with =269 500 J.m-3.K-1for CLIMAmur36 blocks.