不同鋪面對城市熱島效應和熱舒適性的影響

Abstract

在過去的幾十年裡，由於人口的擴張、經濟和基礎設施的發展導致許多地區城市化，城市化將導致大規模的土地覆蓋變化和人為的熱量釋放，從而調節城市環境微氣候。這種增長對城市有負面影響，如城市熱島效應 (Urban heat island, UHI)：指城市中心地區的溫度高於週邊郊區。它會對城市能源消耗、環境質量、人體健康等方面產生深遠影響。其中道路鋪面是導致城市熱島效應增加的主要因素之一，且伴隨著海綿城市和綠色建築的概念出現，透水鋪面及綠色立面的應用成為研究熱點。目前研究表明透水鋪面和綠色立面可以有效降低城市熱島效應，但是每個地區的城市結構與氣候環境不同，使得不同地區內的研究結果較為局限，需要將理論研究應用到實際地區環境中，才能真正體現其減緩效益。因此本研究目的是為確定研究區域內 (停車場區域) 適宜的鋪面以緩解城市熱島效應，並改善行人的熱舒適度，有助於更好地理解城市氣候環境設計策略，以實現較合適的城市更新。同時預測綠色立面水平空間的冷卻範圍並比較透水鋪面對熱環境產生的冷卻效果。 本研究選取台灣受到最嚴重的城市熱島效應影響地區—臺北地區為研究區域，研究方法為數值模擬，使用CFD模擬軟體 (ENVI-met) 作為研究工具，並實地測量進行模型驗證，分析研究區域當前的熱環境狀況，通過數值模擬結果主要討論透水瀝青鋪面、植草型透水鋪面和綠色立面對熱環境的改善效益。 研究結果顯示透水鋪面對於氣候環境具有一定的改善作用。在改善熱島效應方面，除可降低微區域平均空氣溫度外，還能起到減少局部高溫面積的功能。效果最好的鋪面為透水瀝青鋪面，在夏季，透水瀝青鋪面最大減少2.24°C，植草型透水鋪面最大減少2.12°C，綠色立面最大減少0.28°C，主要影響集中在停車場區域，對全局的影響較小。在行人熱舒適性方面，雖然透水瀝青鋪面在夏季14點對生理等效溫度最大減小到6°C，卻未能改變舒適度區間。同時在台灣亞熱帶氣候的條件下，綠色立面存在對氣候環境的冷卻效果，垂直空間最大降溫範圍達到在36米左右，與透水鋪面降溫範圍相似，在水平空間上綠色立面的降溫效在墻體向外3米範圍內顯著，且對於本研究案例而言，綠色立面的影響效果會遜色與透水鋪面。在城市更新方面，本研究建議使用透水鋪面時需考慮風向與建築物的影響，並添加自動灌溉設施利於發揮更好的作用。

Over the past few decades, many areas have been urbanized due to population expansion, economic and infrastructure development, and urbanization will lead to large-scale land cover changes and anthropogenic heat release, there by regulating the urban environmental microclimate. This growth has negative effects on cities, such as the urban heat island effect (UHI): the temperature in the central part of a city is higher than in the surrounding suburbs. It will have a profound impact on urban energy consumption, environmental quality, and human health. Among them, road pavement is one of the main factors leading to the increase of urban heat island effect, and with the emergence of the concept of sponge city and green building, the application of permeable pavement and green facade has become a research hotspot. Current research shows that permeable pavement and green facade can effectively reduce the urban heat island effect, but the urban structure and climatic environment of each region are different, which makes the research results in different regions relatively limited. It is necessary to apply theoretical research to the actual regional environment in order to truly reflect its mitigation benefits. Therefore, the purpose of this study is to determine the appropriate pavement in the study area (parking area) to alleviate the urban heat island effect and improve the thermal comfort of pedestrians. At the same time, the cooling range of the horizontal space of the green facade is predicted and the cooling effect of the permeable pavement on the thermal environment is compared. In this study, the most severely affected area of urban heat island effect in Taiwan-Taipei area is selected as the research area, the research method is numerical simulation, CFD simulation software (ENVI-met) is used as the research tool, and field measurements are carried out to verify the model and analyze the current situation in the research area. Based on the thermal environment conditions, the numerical simulation results mainly discuss the improvement benefits of permeable asphalt pavement, grass-planted permeable pavement and green facade to the thermal environment. The research results show that the permeable pavement has a certain improvement effect on the climate environment. In terms of improving the heat island effect, in addition to reducing the average air temperature in the micro area, it can also reduce the local high temperature area. The best pavement is permeable asphalt pavement. In summer, the maximum reduction of permeable asphalt pavement is 2.24°C, the maximum reduction of grass-planted permeable pavement is 2.12°C, and the maximum reduction of green facade is 0.28°C. The main impact is concentrated in the parking lot area, and the overall impact is small. In terms of pedestrian thermal comfort, although the physiological equivalent temperature of permeable asphalt pavement is reduced to a maximum of 6°C at 14:00 in summer, it fails to change the comfort zone. At the same time, under the subtropical climate of Taiwan, the green facade has a cooling effect on the climatic environment. The maximum cooling range of the vertical space is about 36 meters, which is similar to the cooling range of the permeable pavement. It is significant within 3 meters of the body, and for this study case, the effect of the green facade will be inferior to that of the permeable pavement. In terms of urban renewal, this study suggests that the influence of wind direction and buildings should be considered when using permeable pavement, and adding automatic irrigation facilities will help to play a better role.