Model Based Frequency Domain Estimation of the Thermal Properties of Building Insulation

Estimation of the thermal resistance ( R) and (especially) the thermal capacity (C) of building components from in situ measurements involves the analy sis of dynamic (not steady-state) heat flow data. Such analyses require a suitable dynamic model of the system. Such models, and thus analyses, are most elegantly handled in the frequency domain. Such modeling shows that in realistic experimental situations the presence of the heat flux transducer can have a significant effect on the dynamics of the system, even if the R and C of the transducer are much smaller than those of the component. This is confirmed by analysis of a real data set. Inclusion of the transducer in our model of the system produces estimates which, especially for short and highly dynamic data series, are more accurate and robust than those pro duced using more traditional time domain techniques.