ESTIMATING THE THERMAL TRANSPORT-PROPERTIES OF BUILDING COMPONENTS

Real buildings and their components experience dynamic thermal transmi ssion. It is possible to represent thermal transmission as either a su perposition of local constitutive convolution equations in a local reg ion of the solid oi as a directed graph network between connected ther modynamic regions within the solid. Both the local constitutive convol ution and directed graph network representations are based on response factors which can, in principle, be used to estimate the dynamic ther mal transmission of the building components. The response factors can also be used to predict the performance of the materials under a range of design loadings. These response factors for each representation ca n be estimated directly from time series data of the physical observab les under general stochastic boundary conditions. Indeed, it can be de monstrated that each of the representations can accurately characteris e the thermal performance of building components. The purpose of this paper is to show that only tile local constitutive equations yield, fo r all cases considered, the correct values for the physical properties of the materials under test, whereas the directed graph network repre sentation does not provide consistent estimates. The local constitutiv e equations allow the measurement of thermal conductivity and transmis sion of building components in situ, thus providing a unique insight i nto the actual thermal performance of constructions in use.