植栽對戶外熱舒適之影響研究

An Investigation into the Effects of Plants on Outdoor Thermal Comfort

都市化提供生活的便利性，但造成大量的人工地盤，加上現今廢熱排放與植栽不足的情況，造成都市戶外熱環境不舒適，都市溫熱環境關係到人類居住舒適度與品質，依環境特性規劃植栽可適度改善都市微氣候、減少能源消耗並提升都市生活品質，本研究針對植栽與建築物間之區域進行環境熱舒適之探討，利用實際測量與計算流體力學(Computational Fluid Dynamics，CFD)為預測與分析之工具，藉由實地量測數值驗證CFD之假設是否合理，根據實驗結果提出改善都市微氣候植栽配置之建議，數值模擬所得資料，以無因次法(non-dimensional method)解析，並繪製無因次圖表，透過此圖表可於設計階段瞭解基地之不受遮蔽影響風速(Ur)，並且經由配置狀況，將基本數值帶入本研究所得之回歸公式，即可預估植栽與建築物間生理等效溫度(Physiological Equivalent Temperature，PET)。
部分研究結果得知，喬木灌木混合使用下，顯示蒸發散量越大較能穩定周遭環境舒適度，當蒸發散為0.13 mm/day時PET平均上昇2.98%、上升0.87℃，當蒸發散為0.08 mm/day時PET平均上昇8.03%、上昇2.39℃；當植栽與建築物間未產生不穩定的空氣漩渦情況下，植栽與建築物距離越遠，植栽與建築物間之區域風速衰減幅度越大、熱感受越舒適、生理應力感受程度越輕微。

Urbanization offers more convenient life in the city, however large amount of artificial sites, wasted heat emission and lack of green space caused discomfort in outdoors open space. This study investigate the effects of different planting configuration, as well as environmental impact on thermal comfort for further design principles. This study used field measurement and Computational Fluid Dynamics (CFD) as research methodology, using field measurement’s data to verify the creditability of CFD result and condensed into simple graphs using the non-dimensional method that can be employed during the design process.
The result of the study showed evapotranspiration level 0.13 mm/day, PET average increases about 2.98%, approximately 0.87℃, evapotranspiration level 0.08 mm/day, PET average increase about 8.03%, approximately 2.39℃. Farther distance between trees and building will produce more comfortable environment because of less wind vortex flow.