居室開口部裝設垂直導風板對室內自然通風之影響

A Study on the Influence of Vertical Wind Deflectors on the Natural Ventilation of a Dwelling

本研究針對居室開口部裝設不同角度之垂直導風板，對室內自然通風之影響進行研究，以解決台灣都市中建築物因緊密配置，室外氣流經常平行通過建築物窗面，造成不易導入利用之問題。經縮尺實驗佐證數值模擬之可行性後，即運用計算流體力學（CFD）數值模擬方法進行室內穩態氣流場模擬，探討垂直導風板裝設後之自然通風效益，及在不同入風風向及風速之外在環境變化下，垂直導風板角度對室內換氣率（ACH）與風擊不滿意度（DR）之影響。研究結果主要發現：當風向平行建築物窗面時，其平均ACH 約可較無裝設導風板者增加260%。而當風向與建築立面成45度時，導風板角度（P = 0°~22.5°）有利於室內流場均勻，導風板角度（P = 67.5°）則能降低DR。本研究同時也提出垂直導風板角度簡易調變模式供設計或使用者參考，以確保居室之健康與舒適。

The research aims to analyze the influence of vertical wind deflectors in a typical Taiwan’s dwelling in order to improve the insufficient natural ventilation, especially when the wind direction is parallel to external windows. Indoor airflow steady-state velocity distributions inside the dwelling with the vertical wind deflectors at different angles were simulated by the CFD method. The simulated results were tested and verified by experiments in a reduced scale wind tunnel. Moreover, air change rate (ACH) and draft (DR) of each case were also calculated to compare with those without wind deflectors. Our main findings include that when the wind direction is parallel to the external windows, the vertical wind deflectors can increase ACH by an average of 260%, and when the wind direction is at 45° and the angle of vertical wind deflectors at 0° to 22.5°, the indoor airflow velocity distribution becomes uniform, however, with the vertical wind deflectors at 67.5°, there is a reduction in DR. Finally from the simulated results, a simple reference table for adjusting the angle of vertical wind deflectors with respect to any wind direction is also proposed to help assure the indoor health and comfort in the dwelling types.