Influence of Volume Withdrawal of High-Rise Buildings on the Visibility of Sky View Factor and Urban Microclimate

Abstract

隨著全球都市高度開發並朝向高層高密度化發展，土地使用方式不斷改變，建築型態逐漸朝向高層、高密度化，導致都市溫度不斷上升，影響人體舒適度與生活品質。據研究指出透過建築量體退縮設計，有助於提升都市通風與形塑良好的天空視野與都市環境，進而改善熱島效應並提升環境舒適度。本研究針對台北市高層高密度化之連棟型、雙拼型以及風車十字型等三種建築配置進行都市微氣候分析，比較不同住宅配置形式及天空可視率之量體退縮尺度，同時探討量體退縮尺度與SVF之關係，分析道路寬度（W）、退縮高度（H）、退縮深度（D）與SVF對都市微氣候之影響。結果顯示，透過概念城市模擬方案可得知為改善行人尺度微氣候環境應以底層退縮進行設計，而欲改善都市冠層微氣候環境則應以頂層退縮進行設計。更新改善方案整體以迎風側較背風側之街區建築量體退縮設計更有效改善行人尺度微氣候；不同配置形式量體退縮改善方案影響舒適度效果為風車十字型＞雙拼型＞連棟型配置，且整體以風車十字型配置之底層退縮12m設計為天空可視率及舒適度最佳方案。With the development of high-rise and high-density cities around the world, the land use pattern is changing, and the building pattern is gradually moving towards high-rise and high-density, which leads to the rising of urban temperature and affects human comfort and quality of life. In this study, the national residences of different configurations in the capital city of Taiwan-Taipei are taken as the research object, and three high-rise high-density areas, such as the Townhouse type (Zhongxiao commercial circle-Guangwu new village), the Duplex type (Shida commercial district-Taishun public housing),and the Cruciform type (Minsheng community-Pine Hill new village), using the field measurement and computational fluid dynamics software as the analysis tool, the overall micro-climate simulation analysis was performed using the data obtained from the TETO 480 multi-function environmental measuring instrument and the Sky View Factor (SVF), by comparing the volumetric retreat scale of different housing configurations and sky visibility, and exploring the relationship between volumetric retreat scale and SVF, the effects of road width (W), retraction height (H), retraction depth (D) and SVF on urban microclimate were analyzed. The results show that both the type and scale of housing configuration had an influence on the SVF and the comfort degree of the environment. The best microclimate environment is the windmill cross configuration, and the SVF index is higher with the depth of retreat Through the conceptual urban simulation scheme, it can be concluded that the design for improving the pedestrian microclimate environment should be based on the base retreat, while that for improving the urban canopy microclimate environment should be based on the top retreat. As a whole, the pedestrian-scale microclimate can be improved more effectively by the retrogression design of the building volume on the upwind side than on the leeward side. The effect of different configurations on the comfort is as follows: The Windmill Cross, double mosaic, and multi-span configurations. The overall design of 12m in the bottom of the Windmill Cross is the best one for the visibility and comfort of the sky.