도시 열섬 현상 완화를 위한 입체녹화의 기온 저감 효과 분석

Abstract

(Background and Purpose) Urbanization has increased the population density in urban areas, leading to various environmental problems. Among these, the urban heat island (UHI) effect occurs when urban areas record significantly higher temperatures than the surrounding regions because artificial structures such as roads and buildings absorb and emit solar energy, worsen living conditions, increase energy consumption, and cause health problems. Vertical greening has been proposed to address this issue, wherein plants are placed on building façades and rooftops to expand green spaces and reduce the surrounding temperatures through photosynthesis and evapotranspiration. This study aims to quantitatively evaluate the effectiveness of vertical greening in mitigating the UHI effect by analyzing temperature changes before and after its application in Gangnam-gu, Seoul, using ENVI-met simulations. (Method) This study focused on the Teheran-ro and Gangnam Station areas of Gangnam-gu, Seoul, where high-rise buildings and commercial facilities are concentrated, exacerbating the urban heat island effect. Field surveys were conducted to evaluate the structure, materials, and potential of the rooftops and walls in this area. Based on this assessment, various greening techniques including rooftop greening, wall greening, and vertical gardens were applied. The ENVI-met simulation software was used to model the temperature changes before and after the implementation of the greening techniques. Simulations were conducted during both summer and winter to analyze changes in surface temperature and air quality. (Results) Both rooftop and wall greening effectively reduced radiant heat and air temperature; however, the degree of effect varied by method. Rooftop greening proved to be the most effective at suppressing radiant heat, especially in the afternoon when the air temperature was significantly lowered. It demonstrated superior performance in mitigating the urban heat island effect by blocking solar radiation and releasing heat through evapotranspiration. Wall greening, although less effective than rooftop greening in reducing radiant heat, contributed to reducing heat accumulation and curbing air temperature increase. (Conclusions) This study analyzed the cooling effect of vertical greening on reducing urban heat island (UHI) by evaluating the impact of rooftop and wall greening on radiant heat and air temperature. The results showed that rooftop greening was the most effective in suppressing radiant heat and reducing air temperature, and played a crucial role in preventing heat accumulation in urban areas. Although less effective than rooftop greening in reducing heat, wall greening plays a supplementary role through radiant heat reflection and evapotranspiration. The effectiveness of greening methods can vary depending on the ratio of rooftop to wall area, suggesting the need for customized greening strategies based on building structure and environmental factors. In conclusion, vertical greening is an effective means of mitigating the UHI effect, lowering air temperature, contributing to urban environment improvement, and creating a more comfortable living environment.