Validation of a FEM-program (frequency-domain) and a simplified RC-model (time-domain) for thermally activated building component systems (TABS) using measurement data

In an office building equipped with a thermally activated building component system (TABS) detailed in situ measurements have been performed. The measurements presented in this paper have been concentrated on the concrete core conditioning (CCC) system, which is used for heating and cooling the building. Plastic pipes with circulating water have been placed in the concrete slab. One coil of the thermally activated concrete slab has been measured in detail using 80 measurement points. The measurements include temperature measurements at different heights of the concrete slabs as well as in the suspended floor and in both adjacent rooms. Furthermore the supply and return water temperature, the volume flow for the coil as well as the heat flow at the surface of the concrete slab have been measured. The measurements have been analyzed in the frequency-domain with help of a Fourier-transform. The temperature measurements and the volume flow have been utilized to validate a FEM-program working in the frequency-domain and a simplified RC star network placed in the time-domain simulation environment TRNSYS. The simplified RC-network has been previously validated with help of the FEM-program working in frequency-domain. For the validation of the FEM-program the measured time series have been transformed into Fourier-series and then used as input to the FEM-program performing the calculation in frequency-domain.