Showing 3 results for Urban Heat Island
Roza Vakilinezhad, Navid Ziae,
Volume 1, Issue 1 (1-2022)
Abstract
Buildings have a significant share of global energy consumption and a major role in global warming. Buildings also affect the temperature of their surrounding environment. This paper investigates the effect of Floor Area Ratio (FAR) and urban block configurations on energy consumption, urban microclimate, and outdoor thermal comfort in Tehran with a hot climate, using the simulation method and Ladybug Tools (1.6.0). According to the results, decreasing FAR in an urban block improves urban microclimate while reducing building energy consumption. The results reveal that the effect of FAR on the buildings' energy consumption is more considerable. Decreasing FAR reduces the buildings’ energy consumption and outdoor air temperature. Furthermore, the scattered form of urban blocks consumes the highest cooling energy while having the lowest heating load. The lowest cooling and heating loads are found in the linear and scatter organizations. Considering the dominant cost of cooling energy, the case with less FAR would be the best choice from an economic point of view. For three-story urban blocks, the best case is the courtyard form, while for five and nine-story urban blocks, the best option would be the linear form.
A. Ghobadi, M. Khosravi, T. Tavousi,
Volume 26, Issue 1 (6-2016)
Abstract
This paper examines the utility of the air pollution Model (TAPM) in simulating meteorology and dispersion of PM10 and wind data in order to assess The Impacts of Wind Variability Function on Urban Heat Island for the day of 25, November,
2012 in Karaj city that experienced severe degradation in air quality. Drawing, Skew-T diagrams, maps of surface pressure (500hp), omega (850hp) and atmospheric conditions at 300 – 900hp level are used for analysis. Due to wind patterns, the air pollution behavior is simulated regarding to resolution of 5 km for output amplitude. Simulations of the PM10 and wind data in ten metric levels from three point of city are prepared according to synoptic conditions. Meteorology and PM10 dispersion results indicate that in spite of prevailed wind direction (West to East) in the mentioned day the effect of wind threshold on the air filtration is reduced and heat island formation is occurred as a result of reduction in air flow speed in urban areas. Therefore, it is essential to consider adopted strategies to mitigate urban heat islands such as the principles of bioclimatic architecture, urban morphology, urban infrastructure-related measures (architecture and land use planning) for urban planning.
Hadi Rezaei Rad, Zahra Khodaei, Mohammad Mehdi Ghiai,
Volume 33, Issue 4 (12-2023)
Abstract
Urban planning and morphology are one of the most important factors affecting land surface temperature (LST) and microclimate chrematistics. The production of anthropogenic heat, mainly for cooling systems and lighting, has resulted in significant impacts on the quality of the thermal environment. These impacts include poor air quality, increased temperatures, higher energy consumption, and the development of urban heat islands (UHIs). With the growing urban population and increased building height, especially in metropolitan areas, there have been significant changes in the urban geometry, rate of pollution, amount of heat released, and meteorological parameters. All these factors contribute to the heat island phenomenon and significantly alter the microclimate in urban areas. The goal of this article is measuring the effects of height changes in buildings around Tehran metropolitan squares in a detailed plan on microclimatic changes. As part of a research study, the Hafthoz Square in Tehran was chosen as a case study. The researchers used a combination of simulation techniques (Envi-met) and GIS to detect the spatial variation of Land Surface Temperature (LST) and determine its quantitative relationship with building height and density. This was achieved through simulation modeling for the Narmak neighborhood of Tehran. As Conclusion, the results indicate that comparison on the simulation between the existing conditions and proposed scenario area showed that in the proposed scenario, wind speed and relative humidity decrease and ground surface temperature (UHI) and PPD and PMV indices increase. Therefore, if the detailed plan of Tehran metropolis is realized and implemented in many squares, it will be accompanied by changes in micro-climatic parameters in order to reduce the thermal comfort of citizens.
