Wind-driven natural ventilation of cube-shaped buildings: The effects of roof design and wind direction

The effect of roof design on wind-driven natural ventilation of cube-shaped buildings was studied experimentally in a boundary-layer wind tunnel. The focus was on gable and single-pitched roofs and the flow incidence angle ( β ) in single-sided and cross ventilation of a model subjected to a modeled rural atmospheric boundary layer. Natural ventilation was quantified by the air change rate (ACH) based on tracer gas measurements. For the single-sided ventilation cases, the maximum occurred for the single-pitched roof with the roof pitch at β = 270°. For the cross-ventilation cases, the maximum was achieved for the single-pitched roof with the roof pitch at β = 90°. The ACH was up to 20 times higher for cross‐ventilation cases than for single‐sided ventilation. In general, β and the ventilation type have a more pronounced effect on the ACH than the roof design. The maximum difference in the ACH due to various roof types was 41%, which was observed in cross ventilation at β = 75°. In single-sided ventilation, pitched-roof buildings outperformed the flat-roof building model at most β , except at β = 0°, 15°, 75°, and 90°. In cross ventilation, pitched-roof building models are characterized by higher ACH than flat-roofed building models for 0° < β < 30°. For β close to 90°, the ACH was higher for the flat-roof than for the pitched-roof building model. Design curves for the ACH relative to β are proposed for all roof types to be used as a reference for estimating ventilation trends under the investigated conditions.