Assessment of Thermal and Visual Micro-Climate of a Traditional Commercial Street in a Hot Arid Climate
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School of Architecture, Planning and Landscape Assessment of Thermal and Visual Micro-climate of a Traditional Commercial Street in a Hot Arid Climate Mohamed Mahgoub Bsc, Msc PhD Thesis NewcastleUniversity Newcastle Upon Tyne, UK June 2015 Title page Thesis Title: Assessment of Thermal and Visual Micro-climate of a Traditional Commercial Street in a Hot Arid Climate Full name: Mohamed Hussein Kamel Elnabawy Mahgoub Qualification: Doctor of Philosophy School: School of Architecture, Planning and Landscape Submission Date: April 2015 ii ABSTRACT In the hot arid contexts, the impact of urban climate is often associated with negative effects on outdoor thermal comfort and an increase in the urban heat island (UHI) effect. The primary aim of this research is to investigate the outdoor thermal performance of traditional commercial urban streets located in the hot arid context of Cairo in Egypt. A number of methods were used including field measurements and social surveys. Consequently, urban air flows, temperature and daylight simulations to assess existing and possible improvement scenarios to extend pedestrian thermal and visual comfort were tested. The field measurements were conducted in order to first assess the UHI intensity in the urban street, and to investigate the effectiveness of the traditional design solutions in ensuring comfortable outdoor conditions based on human- biometeorological assessment methods. Validation of results was carried out by comparing measured and simulated results of thermal conditions in the commercial spine ENVI-met is a three dimensional microclimatic model based on computational fluid dynamics (CFD) models and is designed to simulate surface-air interactions in urban environments. It was used to calculate the mean radiant temperature and obtaining the microclimatic maps with problematic areas concerning the pedestrian's thermal comfort for the existing urban configurations. Outdoor thermal comfort was assessed based on a thermal sensation survey and the physiological equivalent temperature (PET), with a comfort range of (24oC - 32oC). To improve outdoor thermal conditions at pedestrian level seven different shading scenarios addressing the form and the opening of shading devices were simulated using CFD Fluent, based on two dependant variables including air temperature distribution and wind velocity. The daylight analysis software (DIVA) was used to evaluate the solar access for the tested cases. The findings show that typology and the opening locations are one of the paramount factors in providing a temperature reduction in the urban scale. As the air temperature was reduced by (2.3oC) for the best case compared to the base leading to a lower PET for the best case recording 32.9oC against 35oC for the base case. iii Related Published Work Elnabawi M, Hamza N, Dudek S. Outdoor thermal comfort in the old Fatimid city, Cairo, Egypt. In: International Conference on “Changing Cities”:Spatial, morphological, formal & socio-economic dimensions. 2013, Skiathos Island, Greece. Elnabawi M, Hamza N, Dudek S. Microclimatic Investigation of Two Different Urban Forms in Cairo, Egypt: Measurements and Model Simulations. In: Building Simulation 2013 Conference - Towards Sustainable & Green Built Environment. 2013, Cairo, Egypt. Elnabawi M, Hamza N, Dudek S. Use And Evaluation of The Envi-met Model for Two Different Urban Forms in Cairo, Egypt: Measurements and Model Simulations. In: 13th International Conference of the International Building Performance Simulation Association. 2013, Chambéry, France. Elnabawi M, Hamza N, Dudek S. Numerical Modelling Evaluation for the Microclimate of an Outdoor Urban Form in Cairo, Egypt.HBRC Journal (2014), http://dx.doi.org/10.1016/j.hbrcj.2014.03.004 iv ACKNOWLEDGMENT Having the opportunity to complete a doctorate was a professional, family and personal experience. In this sense, it could not have been accomplished without the guidance of my committee members, help from friends, and support from my family. Because of them, my graduate experience has been one that I will cherish forever. Firstly, I would like to gratefully acknowledge the effort of both my supervisors, who contributed to this work in various ways. Dr. Neveen Hamza has been an endless source of motivation and advice, and I have learnt a great deal of experience throughout the progress of this research from her. I wish to thank her not only for reading and correcting errors in earlier drafts, but also for the valuable suggestions on my entire work, and especially for all the effort she exerted during the submission period of this thesis. Dr. Steven Dudek, a person with the highest academic and personal qualities, was always ready not only to discuss and confront my ideas, but also to offer guidance, support and advice on arguably any theme and concern. Doubtlessly, I could not have survived the period of my study without their patient support. I am also grateful to my colleagues at Newcastle University, Dr. Mansour Helmy, Dr. Ali Sedki and Mabrouk Al-Sheliby, for their support throughout the work, and special thanks to Dr. Mohamed Al Hajj who was ready to do everything I needed and offered everything I asked. My gratitude extends to my friends, without whom the completion of this project could not have been accomplished: Sameh Elghazzawy, Hisham Elmasry, Ahmed Hegab, Ather Abdelbaky, Jenna and Sarah. I cannot thank them adequately enough for all their love, help and support; their role throughout this period cannot be expressed in words. Finally, a more personal note, I have no way to express my thanks to my adorable grandmother, for her love, warmth and incredible support. Lastly, I would like to dedicate this thesis to my parents, Professor Hussein Elnabawi and Naglaa. Their unconditional love and motivation spurred me on. I owe a great deal to my mother for her sympathy and care; her phone calls from Egypt have relieved hard times and have produced motivation and enthusiasm. As for my father, I wish to sincerely thank him for continuous encouragement, help and advice throughout this study. They have shown v great understanding, patience and support during the course of my PhD study, without which I could not have approached my aim. I hope that I am able to repay them some of their favours and to fulfill my obligations towards them. Special thanks go to my brothers, Kareem and Shadi, and two month niece Camillia, all my family, who gave me every possible support and help. To Dina F. Barakat vi Table of Contents ABSTRACT ..................................................................................................................... iii Related Published Work ................................................................................................... iv ACKNOWLEDGMENT ................................................................................................... v Tables of Contents............................................................................................................xivii LIST OF TABLES .......................................................................................................... xiv LIST OF FIGURES........................................................................................................xvii Chapter One ..................................................................................................................... 1 1. Introduction .............................................................................................................. 1 1.1 Introduction ……………………………………………………………............2 1.2 The conceptual framework ................................................................................. 2 1.2.1 Problem statement .................................................................................. 2 1.3 Research aim and objectives ............................................................................ 12 1.4 Hypothesis and Research questions ................................................................. 12 1.5 Scope and limitations ....................................................................................... 13 1.6 Significance of the study .................................................................................. 14 1.7 Research Methodology..................................................................................... 16 1.8 Research context............... ............................................................................... 19 1.8.1 The geographical setting of the research .............................................. 19 1.8.2 Climate characteristic ........................................................................... 20 1.8.3 Cairo and Al-Muizz urban development .............................................. 23 1.9 The physical pattern development of Al-Muizz............................................... 27 1.9.1 The first Muslim settlements ................................................................ 27 1.9.2 Fatimids (969 – 1171AD) .................................................................... 27 1.9.3 Ayubbids (1171 – 1252AD) ................................................................. 27 1.9.4 Mamluks (1252 – 1517AD) ................................................................. 28 vii 1.9.5 Ottomans (1517 – 1805AD, including the French expedition in 1798AD) …………………………………………………………….28 1.9.6 The Present ........................................................................................... 28 1.9.7 Open/Built Structure ...........................................................................