The quantitative assessment of the effects of the morphology of urban complexes on the thermal comfort using the PMV/PPD model (a case study of Gheytariyeh neighborhood in Tehran)

Abstract

Abstract In the present age, environmental sustainability has been severely challenged because of the human constructions and changes in the ecological landscape of cities so that the issue of the compatibility of urban development with these changes has become especially important. Changes in morphology, structure, form and geometry of the cities, which are themselves caused by changes in the form of urban complexes and geometry of buildings, have a profound effect on the micro-climate and sustainability of urban environments by the efficient adjustments. To assess environmental sustainability or unsustainability in urban neighborhoods, thermal comfort is considered as a good indicator. The assessment of this qualitative concept requires the use of quantitative indicators and assessment tools that can be spatially presented to urban planners and designers to help them in urban development plans. The PMV/PPD model uses heat-balance equations and empirical studies to calculate the ‘predicted mean vote’ and ‘predicted percentage of dissatisfied’, which are somehow derived from the parameters that affect thermal comfort. The innovation of the present study compared to the background of the researches is the evaluation of urban building design policies in thermal comfort, which fills the gap between the evaluations of the level and scale of architecture and urban planning in previous researches. An applied and descriptive-analytical research method has been used in the present study. Firstly, data needed to evaluate the main purpose of the research in the selected site located in the Gheytariyeh neighborhood of Tehran were collected. They are then simulated and analyzed. The results indicate that the difference in the geometry of the buildings and the city blocks can make a difference in the heating comfort of the different city neighborhoods and residents. The recent study has proven that the difference in the city blocks (3- and 4-dimensional and square shapes) can affect the comfort and temperature factors. Spatial simulations conducted in the present study by ENVI-met software show that compared to other indices studied, the PMV and PPD indices have the least distance from the ideal thermal comfort conditions in the design of trilateral high-rise buildings and have the greatest distance from them in the design of rectangular building blocks. It is worth noting that the adoption of policies and regulations related to the design and architecture of urban neighborhoods by the implementation of urban development policies is one of the measures required when the urban development plans are drafted and approved. The simulations model indicates that the minimum and maximum values of PPD index have been respectively equal to 51.06% and 99.96% for the option 1 (three-sided block), 56.09% and 98.26% for the option 2(four-sided block), 57.32% and 98.19% for the option 3(empty middle block) and 58.76% and 98.05% for the option 4 (rectangular block). The present paper has tried to explain the requirements of it.