Thèse de doctorat
Résumé : The increasing challenges caused by non-renewable energy in regard to climate change, the increased flux of migration to urban areas, and the undeniable impact of human activities on these phenomena have given rise to a wide range of scientific work analysing the relationship between urban form and energy. Pioneering research in this field shows a link between the density of cities and their energy consumption. While concerns surrounding sustainable urbanism have grown, urban thinking has evolved, and the interdependence between planning and mobility, and planning and building are increasingly being explored beyond the traditional ways in which they have been considered in isolation. Environmentally conscious design of dense urban forms is thus at the heart of sustainable urbanism. This research uses the concept of urban form to explain the city as a spatial phenomenon. Urban form is proposed as an analytical lens through which the contributions of design characteristics are revealed, for an energy-efficient urban planning policy.Although the link between urban form and energy performance is clearly established, research is lacking on the influence of spatial organization on energy saving in cities from efficient urban fabrics. The urban scale dimension of research on energy consumption attracts much less interest than that of the building, which is very present within the literature. Therefore, the research question was formulated as follows: “How can urban form and energy performance be connected to meet the increasingly unique and changing expectations or needs of places and populations?”. In this regard, the approach adopted in this research is a methodological contribution to knowledge.To answer this question, a research framework was developed with several research methods were employed to answer a set of sub-questions. The first –“What are the links between urban form and energy consumption?”– should be seen as exploratory questions to form a complete picture of the problem. It is answered through a combination of literature review and analysis of urban form elements. The second sub-question –“How can urban form indicators be integrated into the decision-making process for an energy-efficient urban planning policy?– is a fundamental question and is theoretically answered by a literature review and through the development of a theoretical framework. The third sub-question –“What are the links between socio-economic variables, transport infrastructure energy consumption and urban form?”– is the first of three questions that structure the empirical research. It resulted in a statistical data analysis for the selected case area, i.e. the Brussels-Capital Region. The fourth sub-question –“ What are the links between building geometry and solar gains?”– is answered with the analysis of a 3D simulation model of a district area in renovation. The last sub-question –“What are the design priorities required to reduce urban energy use?”– led to the development of a conclusion at multiple scales of urban form analysis. After introducing the topic, the research question and the research framework in the first chapter, chapters 2 to 6 respectively respond to each of the sub-questions. To answer the first sub-question, a historical analysis of the relationship between energy and urban form is presented in chapter 2. The discipline of urban form study in the fields of architecture urbanism and geography introduced four main schools of thought and three main approaches to analyse the urban form during the period 1960-2018. These schools support the viability of urban form analysis as an instrument for planning, as it makes us consider how urban form design affects the energy usage of the city. At the same time, urban planners need to consider the urban not to be simply a set of data, but a subject of inquiry that depends on an assumed initial definition and conceptualisation.In chapter 3, the methodological aspects used in this research are detailed and give an answer to the second sub-question. Four complementary systems of urban form elements are highlighted and connected to the energy indicators identified in the literature review. The scale of analysis for each of the urban form elements is also presented in this chapter with argumentation and detailed definition of the urban indicators. At the same time, the econometric statistical analysis is developed and explain the potential of; correlation, cointegration and causality analysis in building an efficient urban planning policy. In chapter 4, the Brussels-Capital Region mobility data for a 26 years period (1990-2016) are statistically analysed. The link between urban form indicators, transport and socio-economic indicators show the importance of road length development on increasing energy consumption in transport for the region. It also highlights the need for policy planning more inclined to take the “time” into consideration to be able to support future energy-efficient policy measure. In chapter 5, the analysis of the relationships between urban form and energy is scaled down to the street and building scales. A solar analysis is conducted on two different urban form models (the closed block and the open block). The results point to the importance of urban planning design considering open space an object of inquiry rather than simply leftover space between buildings. It is also reasserting the need for 3D model analyses in the preliminary stages of the conception of the technical specifications provided by the region for each project. Finally, in the chapter 6, the applicability and merits of the theoretical framework are first reflected upon. Next, the newly gained insights about the processes behind urban form and energy nexus are presented. Then, an answer is given to the main research question in the form of recommendations. These recommendations are based on the idea that the study of urban form development could be used as a powerful tool for crafting urban regulation guidelines and practices for a more integrated, sustainable urbanism.