Studying the solutions of urban heat island mitigation through greenery and permeable surface in Tehran

Subject Areas : Architecture and urbanism

Marzieh Farbudi ¹ , Zahra Zamani ²

1 - Masters student, Kish international campus, University of Tehran.
2 - Assistant professor, Arch. Technology, School of Architecture, College of Fine Arts, University of Tehran. *(Corresponding Author)

Received: 2021-01-17 Accepted : 2021-05-23 Published : 2022-04-21

Keywords: Envi-Met, Green infrastructure, UTCI index, heat island, Dragonfly,

Abstract :

Background and Objective: The increase in development of urban spaces has caused the phenomenon of urban heat island. One of the main factors that disrupts the rain cycle, reduces relative humidity in urban environments, and ultimately raises the temperature is the reduction of permeable surfaces and green spaces in cities. The heat island is intensified in the city center and in high-traffic areas. The purpose of this study was to modulate this phenomenon at the central part of Tehran and to provide solutions to adjust the temperature. Material and Methodology: This research was carried out in two phases by using a simulation method. In the first phase (on an urban block scale) the current situation and the situation proposed by the authors were simulated using Ladybug and Dragon Fly to compare UTCI index and dry-bulb temperature. In the second phase, part of the studied urban block was selected and the micro-climatic model were simulated in three modes of the current, proposed and the optimal situation with Envi-met on August 6, 1998. Subsequently, the effect of building materials, floors with different permeability, grass, trees and water on wind speed, temperature, relative humidity, radiant temperature and carbon dioxide concentration was studied. Findings: Finally, the optimal model that included trees, water, grass, permeable materials, trees and green roofs reduced the temperature (to four degrees), irradiation temperature (4 to 5 degrees), the carbon monoxide concentration and wind speed and meanwhile increased the relative humidity up to 10% compared to the current situation. Discussion and conclusion: The results indicated that the UTCI index was adjusted as urban green infrastructure and permeable pavement increased. The tree also had the greatest effect on lowering the temperature than other parameters.

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