CFD Analysis of Turbulent Natural Ventilation in Double-Skin Façade: Thermal Mass and Energy Efficiency

Abstract

Double-skin façade provides many opportunities for energy conservation in buildings. This work summarizes the results of a computational fluid dynamic (CFD) analysis, which was carried out to investigate the effect of blind and thermal mass concrete on the thermal performance of a double-skin façade. Navier-Stokes equations, turbulent k-ε model, and discrete ordinates radiation model have been used to simulate the airflow and to study the airflow pattern. It was shown that the airflow patterns for natural ventilation with a blind and thermal mass concrete were very complex with multiple vortex structures. On the other hand, the heat flux and the airflow velocity at the inlet have a significant impact on the natural ventilation airflow rate. The Rayleigh number for turbulent flow was in the range of 107≤Ra≤108 using a blind. However, the Rayleigh number was less than 107 using thermal mass concrete. On the other hand, thermal mass increases the energy performance of natural ventilation. A good agreement was performed by comparing the experimental data and the simulation results.