|
As a natural ventilation strategy, general gravity ventilators can be installed on the roof of an industrial building. Gravity ventilators allow the escape of the warm air and air contaminants due to both(either) buoyancy and(or) convection. Unfortunately, the appropriate design data for this type of ventilators could not be found except for the design data in commercial catalogues in which there is no scientific reference. In this study, the ventilation rates of gravity ventilator were thus evaluated for the several design parameters, i.e. 1) wind direction, 2) wind speed and 3) temperature differences between the exterior and interior of a building. A commercially available CFD (Computational Fluid Dynamics) package was used to estimate the ventilation rates numerically. The factorial combinations of 3 parameters (3 wind directions, 6 wind speeds and 5 temperature differences) which are 90 cases in total, were simulated. The ventilation performance were enhanced as 1) the wind direction is close to the longitudinal direction of industrial building, 2) wind speed increases, and 3) the temperature difference between the exterior and interior of a building increases. in addition, the temperature difference is the dominant factor in the lower wind speed(0∼1m/s) while the wind speed is in the higher wind speed (2.5∼10m/s). As a result of comparing the simulation data with the data presented in the commercial catalogues, the commercial date were overestimated. Further study is under way.
|