Thermal performance and airflow analysis of a new type of Double Skin Façade for warm climates: An experimental study

Abstract

Double Skin Facades (DSF) integrated with shading devices are increasingly implemented in tall buildings to protect the building from excessive solar radiation. However, the potential overheating of DSF in warm climates leads to lower DSF performance in hot seasons. In this study, a new type of DSF named Interstitial Slat-blind DSF (IS-DSF) has been introduced featuring wind-induced ventilation and insulated shading devices. This research aims to highlight the capabilities of the proposed DSF in a warm climate and identify contributing environmental and geometrical factors for overheating risk reduction of IS-DSF. To this end, an experimental study was conducted in a scaled room located in an outdoor environment on summer days in Brisbane, Australia. First, the test room with and without IS-DSF was studied to assess the performance of IS-DSF for controlling indoor temperature. Next, a parametric evaluation was conducted including geometrical variables (cavity width, slat blind angle) and environmental factors (approaching wind speed and direction, air velocity in the cavity and solar radiation). It was found that the most influential factor for controlling the cavity overheating risk is the air velocity inside the cavity while the effect of blind slats angle is negligible. A cavity airflow velocity threshold was estimated beyond which the overheating of the IS-DSF cavity becomes negligible. Correlations were established to predict cavity airflow velocity from approaching wind speed for IS-DSF with different lateral openings. Overall, IS-DSF showed a reduction in surface temperature of the cavity as a potential advantage compared to conventional DSF to reduce the overheating risk of the DSF's cavity in a warm climate. • Addressing the overheating risk of Double Skin Facade (DSF) in warm climates. • IS-DSF is introduced featuring vertical openings and insulated shading devices. • An air velocity threshold for overheating estimation is experimentally identified. • Correlations are established to predict the air velocity in DSF's cavity.