69 Int. J. Architect. Eng. Urban Plan, 29(1): 69-78, June 2019 RESEARCH PAPER Environmental Design Developing a Tool for Analyzing and Generating the Fittest Urban Morphology Based on the Sky View Factor and Insolation (A Case Study on Yazd) Sh. Roshanzamir 1,* , M. Farhadian Dehkordi 2 1 PhD, Department of Architecture & Urban Design, Art University of Isfahan, Isfahan, Iran 2 PhD. Candidate, University of Applied Arts Vienna, Vienna, Austria Received: November 2018, Revised: April 2019, Accepted: April 2019, Available online: June 2019 Abstract Urban morphology, including buildings’ typology and configuration, affects sky view factor and insolation as two of the most prominent parameters in urban microclimate, particularly in extreme environmental conditions. This research aims to generate various rule-based urban block typologies in a parametric environment and then evaluate them based on the parameters mentioned above to find the fittest climate responsive morphology. Grasshopper, Ecotect, and Genetic algorithms are used for evaluation in relatively short computing time. Introducing a high-speed and user-friendly environment for designers to generate forms and evaluate them in several iterations was the main consideration. The proposed tool consists of two parts, namely generative algorithms to create various rule-based morphologies and analytics algorithms to find the fittest climate responsive urban morphology based on insolation and sky view factor. As a case study, the focus is on different urban morphologies in Yazd to find the fittest option. The maximum sky view factor and minimum insolation on building surfaces are ideal in hot and arid climates; however, these two parameters suggest contradicting solutions for urban morphology. Considering the existing urban fabric in Yazd, various block typologies and arrangements are parametrically generated. In each scenario, the evaluation iterations identify the most suitable typologies and arrangements. After comparing the fittest versions of different types, the most proper building typology, collective arrangement, and the best orientation are provided. Keywords: Sky view factor, Insolation, Urban morphology, Building typology, Parametric design, Yazd. 1. INTRODUCTION Due to the limitation in energy sources and problems like Urban Heat Island (UHI), designers should consider the enhancement of urban microclimates for inhabitants‘ comfort and reduction of energy consumption in active and passive ways. Sky View Factor (SVF) and insolation are two of the utmost factors that are directly linked to urban density and configuration and influence urban microclimate, energy production, and energy consumption by affecting received daylight and solar access, daytime heat gain, and night-time heat loss through radiation or exposure to the outside environment. This article tries to introduce a low-cost, fast, and accessible tool to generate, evaluate, and optimize different design scenarios based on these factors. As a case study, the proposed tool is examined on different block configurations in Yazd, a city located in the central part of Iran. * Corresponding author: Sh.Roshanzamir@aui.ac.ir Tell: +983132200003 The SVF is a dimensionless parameter ranges from zero to one. As defined by Oke ―It represents the fraction of visible sky on a hemisphere centered over the analyzed location‖ [1]. The relation between urban geometry, SVF, and UHI is well studied [1-5]. Many types of research consider SVF the main index of UHI [6-7], in the sense that the higher the mean SVF, the lower the UHI formation. However, this can lead to more exposure to solar radiation. In this case, insolation comes to play. Insolation is the solar radiation at the surface of the earth, represented in units of energy/square meter [8]. This can be a factor to evaluate daytime heat gain through radiation. As discussed, insolation and SVF can have contradictory effects on the optimization process of the block‘s form, layout, and orientation. For instance, to achieve the maximum radiative heat transfer to the sky, maximum openness and SVF are needed, which means an increase in daytime insolation and heat gain. Most of the related studies on SVF have failed to consider this contradiction [9-11], and few studies have merely pointed to this issue without directly including it in their analyses [6, 12-13]. Downloaded from ijaup.iust.ac.ir at 13:52 IRST on Sunday December 13th 2020 [ DOI: 10.22068/ijaup.29.1.69 ]