Description

This project simulates airflow inside a building’s double-skin façade (DSF) using ANSYS Fluent. In a DSF, solar heating warms the cavity air, which then rises by buoyancy, contributing to passive heating and ventilation.

The 3D geometry (DesignModeler) is a 0.6 × 3.2 × 5 m rectangular cavity with two parts: a duct section for airflow and a glazed section that absorbs solar gains. Openings include a 0.2 m inlet at the bottom of the glass wall and a 0.2 m outlet near the top. Meshing (ANSYS Meshing) produces 490,725 elements.

Facade Methodology

The study evaluates buoyancy-driven motion of warmed air inside the DSF. The glass region is assigned a uniform volumetric heat generation of 6940 W/m³ to represent solar input. Building walls are brick with convective exchange to the interior at T = 300 K and h = 23 W/m²·K (free convection).

Supply air enters the façade at 304.55 K and atmospheric pressure. Buoyancy is captured by modeling air density via the ideal gas law and applying gravity = 9.81 m/s².

Conclusion

Post-processing yields 2D/3D pressure, velocity, and temperature contours plus velocity vectors. The vectors show an upward flow within the cavity, confirming buoyancy-driven ventilation in the double-skin façade.