Abstract

Louvers are an integral component of natural ventilation. This study presents a numerical analysis using
computational fluid dynamics (CFD) on cross ventilation in an isolated building equipped with louvers. Opening
configurations of (i) center-center, (ii) top-top, (iii) bottom-bottom, (iv) top-bottom and (v) bottom-top (whereby
the configurations are defined as ‘windward’-‘leeward’) with varying louver configurations of No-Louver (NL),
0◦, 15◦, 30◦ and 45◦ are studied. Atmospheric Boundary Layer (ABL) condition is applied at the inlet of the flow
domain and Renormalization Group (RNG) k-ε turbulence model with enhanced wall function (EWT) is
employed for the numerical simulations. Grid sensitivity analysis is performed using Grid Convergence Index
(GCI) whilst model validation is performed using Factor of two of observation (FAC2) analysis. The highest
dimensionless flow rate (DFR) is achieved by configuration top-top without louvers at 0.719. The highest air
exchange efficiency (AEE) is obtained by louver angle of 15◦ for center-center configuration at 53.4%. The lowest
AEE obtained is obtained at louver angle of 0◦ for top-top configuration at 20%, indicating short-circuiting of air.
For configuration bottom-bottom with louver angle of 30◦, high AEE is obtained but at the cost of reduced DFR.
The optimal balance between AEE and DFR can be obtained by factor-optimization (α) as presented in this paper.
The study concludes that opening position alongside louver angle plays an integral role on the internal airflow,
pressure coefficient, DFR and AEE in natural cross ventilation.