不同都市密度下建物群立體綠化比例對都市微氣候之影響

隨著都市化集中趨勢，都市人口密度逐漸變高，朝高層建築（High-Rise Building）高密度發展以滿足大量人口的需求，使得都市微氣候產生變化。大量興建建築物壓縮到綠地及開放空間，為提升整體綠覆率，綠化系統由水平空間延伸至立體空間。建築牆面綠化被認為能有效改善都市高密度發展所帶來的微氣候環境影響，多項研究顯示建築牆面100%綠覆率所帶來的效益為佳。本研究以建築100%垂直綠化的基礎，探討在不同都市密度（低、中、高密度）配置不同比例綠化棟數（0%、35%、65%、100%）共12個方案，以行人高度分析對於都市微氣候之影響及不同方位之差異。結果顯示無論有無綠化配置，隨都市密度及建築量體高度越高時，人行高度風速逐漸增加，建築量體東向、南向及北向立面平均風速逐漸提升，但背風西向立面逐漸下降，迎風面之東向風速最高及背風處的西向溫度最高。各種密度配置綠化棟數遞增，風速逐漸降低，成反比趨勢。相較0%無綠化，配置35%綠化棟數可達到降低各密度最少風速及最佳降溫效果，其中中、低密度為降低最少風速7%及低密度最佳降溫7%。各向差異為高密度溫度衰減幅度較大，以低密度西向降低風速2%及降溫8%效果最佳。高密度較中低密度都市行人風場為高，配置35%綠化比例可降低最少風速且降溫效果明顯。中、低密度較高密度平均溫度高、風速低，以背風面之西側綠化設計，減少植栽摩擦影響及降溫效果佳。

關鍵字

都市微氣候；都市密度；立體綠化；綠覆率；計算流體力學（CFD）

並列摘要

Along with inclining urbanization and population, cities are transforming towards high-rise buildings to fulfill the needs of the dense population, resulting in changes of the urban microclimate. The number of urban green space has been declining. Thus, to increase green coverage ratio, urban greening is gradually extended to vertical greening. Studies have shown that vertical greening on buildings is capable to improve microclimate in high-density urban areas. Under the basis of 100% vertical green coverage rate, this paper studied 12 cases with different green ratio (0%, 35%, 65%, 100%) on different urban densities, focused on pedestrian-level height to analyze the impact towards urban microclimate. The results show that despite greening, wind speed on north, south, and east increases as the building heights increase, while west side has the highest temperature and lowest wind speed. Vertical greening decreases wind speed. 35% greening ratio has the most effective on decreasing urban temperature, while maintaining urban wind speed. Additionally, 35% greening ratio on low and medium density urban areas have the most effectivity. Pedestrian-level wind speed is the highest on high-density areas. 35% ratio of vertical greening on high-density areas can lower wind speed, and decrease urban temperature most effectively. On low and medium-density areas, temperature is higher and wind speed is lower. Vertical greening on the west side is recommended to decrease temperature without disrupting too much air flow.

並列關鍵字

Urban Microclimate ； Urban Density ； Vertical Greening ； Green coverage ratio ； Computational Fluid Dynamics (CFD)

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