Experimental and numerical analysis of heat transfer and airflow on an interactive building facade

The designers desire to improve the transparency of the facade as aesthetic feature and the technical need to improve indoor environrnent, acoustic and energy reduction drive tovard the concept of Double Skin Facade (DSF). It would be then important to understand the real operating behavior in order to be able to choose the best typology in function of the specific location and environmental conditions. The use of the Computational Fluid Dynamic (CFD) can be the tool for an inclusive approach that could lead to the definition of any empirical formulation that could describe, with an acceptable, known error, the behavior of the DSF in its operation environment. The purpose of this work is to produce a comprehensive CFD: analysis to understand DSF behaviour in the different environmental conditions that could be a background for the development of an easy-to-use tool for designers that are approaching to the problem without specific thermo fluid dynamics knowledge. The DSF has very complex thermo-fluid phenomena under the outdoor environmental conditions and in order to develop a suitable computer procedure a decoupled method for the radiative heat transfer has been implemented to carry out the simulations. Full scale test room experimental data has been used to validate the procedure. Firstly, the global net energy balance and the optical properties of the DSF were evaluated from the measured data. Then a CFD software has been used to calculate temperature and flow distributions in the DSF. The results show that the thermo-fluid phenomena can be approximated to be two dimensional. The CFD can calculate the temperature distribution in the DSF with reasonably good accuracy. The results also show that the decoupled method for radiative heat transfer is reasonable acceptable for such an advanced DSF.