Wind-driven natural ventilation in a low-rise building: A Boundary Layer Wind Tunnel study

摘要

Indoor Air Quality (IAQ), energy efficiency through passive building design strategies and sustainable construction practices have been highly prioritized in recent years. This paper presents a Boundary Layer Wind Tunnel study on wind-driven natural ventilation for a low-rise building at a model-testing scale of 1:20. The experiment consists of testing various size openings in a single wall, opposite side walls and adjacent side walls with and without portioning walls, with and without opening cover screens, with and without internal volume correction for 36 different wind angles of attacks (unless symmetrical). For the size of the building and openings considered, the experimental analyses indicated that internal volume correction using velocity scaling was important, although this criterion could be relaxed for cross-ventilation with openings in opposite walls. The internal pressure due to cross-ventilation was 1.5-2.5 times higher for A_(inlet)/A_(outlet) > 1 compared with ratios A_(inlet)/A_(outlet) < 1. In general, the lower the opening ratio (or inlet to outlet ratio), the higher the pressure drop inside the building. For an equivalent opening ratio, openings on opposite-walls generated a higher pressure drop compared to openings on adjacent-walls. Room-partitioning significantly affected the distribution of internal pressures, and hence the pressure drop that favored the ventilation in each room for the considered partitioning case. In addition, the total discharge coefficient C_(d_total) and the ventilation rate Q/(V_rA) increased with an increase of the opening ratio. The inlet discharge coefficients obtained in this experiment ranged from 0.65 to 1.08, similar to the results of various early studies.