不同植栽種類對薄層式綠屋頂熱效益影響之研究

Thermal Benefits of Diverse Plant Species on Extensive Green Roofs

As global warming becomes more apparent, installing extensive green roofs is being strongly promoted in cities. Research reporting the thermal benefits of extensive green roofs is plentiful; however, additional studies related to plant materials are necessary. Thus, the main purpose of this study was to investigate the thermal benefits of different plant species on extensive green roofs. Twelve plant species widely used in extensive green roofs in Taiwan were studied. The results indicate that extensive green roof significantly reduced rooftop surface temperature at midday. The cooling effects from the modules ranged from 16.44 to 24.93°C. Modules covered with different species showed greater variations in temperature reduction. The modules covered with Kalanchoe tubiflora (Harvey) Hamet and Plectranthus amboinicus (Lour.) Spreng exhibited greater cooling effects, while Arachis duranensis Krapov. & W. C. Greg. and Callisia repens L. had lower cooling effects. Plant species with thicker leaves and higher plant albedos exhibited stronger cooling effects. In addition, erect stem plants demonstrated a higher cooling effect than did creeping stem plants. The results of this study could aid landscape architects in selecting more effective cooling plant materials for extensive green roofs. 隨著暖化日益明顯，綠屋頂的建置已在許多都市中被大力推廣；關於綠屋頂熱效益的相關研究相當多，然而對於植物材料的選擇影響其降溫效益的相關研究仍有待更多的研究投入，因此本研究主要目的係探討不同植物種類對薄層式綠屋頂降溫效益之影響。本研究選擇十二種臺灣常用的薄層式屋頂綠化植物進行探討，研究結果指出薄層式綠屋頂的降溫效益約介於16.44℃到24.93℃，不同植物覆蓋的模組有不同的降溫效果，以洋吊鐘、班葉倒手香覆蓋模組降溫效果較大，而以蔓花生、翠玲瓏降溫效果較小。以植物具有較厚的葉片、植表反照率較高，其降溫效果較佳，而直立型植物其降溫效果較匍匐型為佳。研究結果將可協助設計者選用降溫效果較佳的植物材料。