| 摘要: | 由於人類經濟活動以及人為建設的產生，都市中承載過多的熱能使熱平衡被破壞，包括太陽輻射熱能被大量的人工材質吸收且無法散去，再加上都市交通、冷暖氣的排放，導致蓄積過多人工廢熱，且無法被都市風流所排出，致使都市地區相對於其周邊地區猶如一座發熱的島嶼，稱之為都市熱島(Urban Heat Island, UHI)。
此外，都市中大量人工建物影響都市自然的風流，形成都市微氣候(Micro Climate)。近年來國內外有關此議題多以計算機流體力學(Computational Fluid Dynamics, CFD)做為模擬研究及分析的重要工具，並運用設計模型改善方式達到都市風場的模擬及風廊的改善，但針對都市熱環境與熱流之關係模擬較為缺乏，且針對人行尺度下的熱環境模擬更是少之又少，這是因為在人行尺度下，會造成影響的因子較多，如植栽種植多寡、土地使用行為、街道高寬比、遮蔭率、騎樓等。
因此，本研究選定新生南路二段之兩側人行道為研究對象，大安森林公園側之人行道屬植栽綠化較多之區域，西側人行道屬多樣化土地使用之建物密集區，採實地量測結合軟體模擬的方式，運用動態步行量測法以每三公尺一個測點，實測器材以每50公分架設，從0至300公分做垂直熱環境之數據測量，共7個垂直測點，實測設備包含空氣溫溼度紀錄儀、紅外線溫度計以及紅外線熱像儀，以取得空氣溫濕度、表面溫度、等微氣候數據，並搭配風速計等手持儀器進行校正輔助，以確保量測數據的準確性；隨後建立新生南路二段街道系統之三維模型，將實測數據導入至街道系統之三維模型，並利用WindPerfectDX進行垂直熱環境模擬。
透過本研究，建立新生南路二段街道系統之垂直熱環境數據庫，並以此實測數據分析得出當高度在2m時，溫度會達到最低值，隨後進入熱流模擬軟體，搭配設置完成之網格模型及邊界條件，進行新生南路二段兩側人行道之熱環境模擬與實測之對比，透過此成果得出了遮蔭越多、建物遮蔽面積越大，空氣溫度則越低，並進一步運用都市設計手法於街道系統三維模型進行優化設計改善，得出了減少樹距以及改善街道高寬比，均可以有效的抑制熱環境，最後基於此研究成果，提出人行尺度觀點下都市設計對熱環境抑制效益之改善建議。
Due to human economic activities and the construction of artificial structures, urban areas bear excessive heat, leading to a disruption of thermal balance. This includes the absorption of solar radiation by artificial materials without efficient dissipation. Additionally, emissions from urban transportation and heating/cooling systems result in the accumulation of excessive waste heat that cannot be effectively dispersed by urban airflow. As a result, urban areas become heat islands, generating more heat compared to their surrounding regions, and this phenomenon is referred to as the Urban Heat Island (UHI) effect.
Furthermore, the presence of numerous artificial buildings in urban areas affects the natural airflow, creating a microclimate within the city. In recent years, Computational Fluid Dynamics (CFD) has been widely used as a simulation and analysis tool for studying and improving urban airflow and wind corridors. However, there is a lack of comprehensive simulations regarding the relationship between urban thermal environments and heat flow. Particularly at the pedestrian scale, there is limited research on thermal environment simulations due to the numerous factors that influence it, such as the presence of vegetation, land-use behaviors, street dimensions, shading, and sidewalks.
Therefore, this study focuses on the pedestrian sidewalks on both sides of Section 2 of Xinsheng South Road. The sidewalk adjacent to Da'an Forest Park features a significant amount of greenery, while the sidewalk on the west side is located in a densely built area with diverse land uses. The research approach involves a combination of on-site measurements and software simulations. A dynamic walking measurement method is employed, with data collected every three meters using measurement devices placed at intervals of 50 centimeters, covering a vertical range from 0 to 300 centimeters to capture vertical thermal environment data. The measurement equipment includes air temperature and humidity recorders, infrared thermometers, and infrared thermal imaging cameras, enabling the collection of microclimate data such as air temperature, surface temperature, etc. Handheld instruments such as anemometers are used for calibration to ensure measurement accuracy.
Subsequently, a three-dimensional model of the street system on Section 2 of Xinsheng South Road is established. The measured data is incorporated into this model, and the WindPerfectDX software is employed to simulate the vertical thermal environment. Through this study, a database of vertical thermal environment data for the street system on Section 2 of Xinsheng South Road is established. Analysis of the measured data reveals that the temperature reaches its lowest point at a height of 2 meters. The simulated thermal environment of the pedestrian sidewalks on both sides of Xinsheng South Road is compared with the measured data using heat flow simulation software, considering the established grid model and boundary conditions. The results indicate that increased shading and increased building obstruction lead to lower air temperatures. Furthermore, urban design techniques applied to the three-dimensional model of the street system, such as reducing tree spacing and improving street dimensions, effectively mitigate the thermal environment. Finally, based on the research findings, suggestions for improving the effectiveness of urban design in suppressing heat environments are proposed from a pedestrian-scale perspective. |
