Use of Coandă nozzles for double glazed façades forced ventilation

• A Coandă nozzle is modeled as ventilation system for DGF.
• Coandă nozzles allow to easy implement control systems on DGF ventilation.
• Coandă nozzle ventilation shows improvements on reduction in solar load gains.

Fans are the most widespread system used to implement forced convection ventilation for double glazed façades (DGF). However, the implementation of fans in a façade require an electrical supply for the motors, solid supports for the fans, and the installation has to meet fire safety regulations required by local laws. These facts, added to the need of a regular maintenance program for the fans and the possibility of noise and vibration generated by the moving parts of these equipment, might increase the final cost of the façade and reduce the comfort inside the building.In this paper the feasibility of using nozzles for DGF ventilation is evaluated. The nozzles selected for this study are based on the Coandă effect. For this investigation, a CFD model was used to simulate a Coandă nozzle. The modeled nozzle was simulated for different flow rate conditions and velocity and pressure fields obtained in the nozzle outlet were imposed as an inlet boundary condition in an upper crossed lateral ventilation model for a DGF. Results obtained for heat flux, and reductions in solar gain loads for different operating conditions were obtained and compared against previous results for vertical and horizontal DGF ventilation in a similar geometry.