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This thesis aims to examine the causal mechanisms of living environments on leisure mobilities and verify whether their inclusion is actually able to challenge the compact city as a sustainable urban form. The research focuses on the Swiss case and in particular the cities of Geneva and Zurich. The empirical approach is based on three types of additional analysis carried out in these areas: contextual analysis, quantitative analyzes based on data from the Mobility and Transport Microcensus 2010 and qualitative analysis through interviews. The main results are the following: â ¢ We find the existence of two opposing logics of association between land density and distance traveled: a decreasing link to daily mobility, but a positive correlation for occasional mobility (day trips and overnight trips). The denser is the living environment, the greater is the distance for this mobility. â ¢ Adding the two types of mobility to obtain a total average, we find that the inner city dwellers displayed, ultimately, much higher totals than would suggest the analysis of their daily mobility alone which therefore represent an invitation to invalidate the link compact city=short distances. â ¢ By transforming these distances into environmental impact, however, our calculations show that even while taking into account the many trips of urban dwellers, the negative relationship between total energy consumption and land density of the territory remains. â ¢ By examining in detail the share of leisure in daily and occasional mobility, we see that the logic of compensation is not what structures the links with urban environnements. In everyday life, the logic of proximity prevails: to live in the centre is rather correlated to more compactophile leisure and residing in the periphery to more leisure oriented towards the attributes of nature. â ¢ For occasional trips, we show firstly that compactophile mobilities represent a large part of these practices among all respondents, and secondly, that even in the case of very important and high energy consuming naturophile mobility, the relationship with the density of the living environment is not established. The central Genevans and are much less consumers of this type of leisure than people in the centre of Zurich even though their city is much more airy and green. Moreover, we also highlight, in peri-urban dwellers, a very intense mobility or this purpose. â ¢ The interpretation that we propose refers to lifestyles and residential choice of city dwellers which takes into account their leisure aspirations. These tastes are then translated into specific leisure activities and travel. In everyday life, they rely on proximity and functional, social and sensitive attributes of their living environment that they have chosen largely also for this. When it comes to breaking the routines during holidays and vacations, the same lifestyles result in significant occasional mobility whose motives can register in continuity of their daily lifestyle (loving the same things elsewhere) or by contrast (appreciate the diversity of spaces). In both cases, these motivations echo the valorisation of the diversity inherent in urbanity without questioning the urban residential location quality itself. Our results lead us ultimately to reject the compensation effect hypothesis and reaffirm, against the defenders of the sprawl-city, the virtues of the compact city, which remains a sustainable urban form, including for our leisure mobility.

Keywords: district heating network ; heat load ; tree-shaped or meshed configuration ; pumping energy ; modifications ; extension ; simulation ; pipe diameters ; discounting values ; combinatory optimisation ; knowledge-based rules ; chauffage a distance ; reseaux ; demande thermique ; configuration maillee ou arborescente ; energie de pompage ; modifications ; extension ; simulation ; diametres de conduites ; couts actualises ; optimisation combinatoire ; regles basees sur des connaissances These Ecole polytechnique federale de Lausanne EPFL, n° 1304 (1994)Chaire de recherche operationnelle SOGroupe GnansounouJury: F. Bosshard ; P.-A. Haldi ; Th. Liebling ; Y. Smeers ; I. Smith Reference doi:10.5075/epfl-thesis-1304Print copy in library catalog Record created on 2005-03-16, modified on 2016-08-08

Actuellement, les installations CAD sont souvent surdimensionnées par manque de connaissance pour garantir les besoins thermiques de tous les clients. Ce dimensionnement se fait pour un point de fonctionnement à la puissance maximale, puissance à fournir seulement de 1 à 5 jours par an. Une optimisation énergétique grâce à un logiciel pourrait permettre une économie des matières premières des conduites, des déperditions thermiques et de temps lié au dimensionnement. Le but de ce projet est de développer un algorithme itératif en C++, afin de calculer les pertes de charge en régime laminaire et turbulent selon le besoin de chaleur des clients dans un réseau ramifié. L’algorithme considère le réseau comme un arbre composé des points, selon un fichier d’entrée XML. Afin de simplifier la structure, seule la conduite d’aller est considérée. En plus seuls les points des divisons ou des consommateurs sont considérés comme importants dans une première version du Solver. Ces derniers sont nommés feuilles. Les entrées sont principalement l’énergie consommée par chaque sous-station, les longueurs des conduites, les propriétés des conduites et les températures d’aller et de retour du réseau. Les sorties du Solver se trouvent sous forme de fichier texte : débit, vitesse de l’écoulement, perte de charge, différence de température pour chaque branche, température et pression à chaque feuille. L’outil développé très simplifié permet d’imprimer les résultats pour chaque feuille principale dans la conduite d’aller et la visualiser dans QGIS. L’algorithme a été testé sur un cas d’étude réelle. Le résultat du Solver par rapport au tableur Excel actuellement employé par un bureau d’ingénieur a pu montrer son potentiel de précision et sa vitesse de résolution. Tous les résultats visuels sont cohérents par rapport aux résultats calculés.

Renewable and available in abundance, incident solar radiation is an ideal candidate for energy production. The development of nanostructured coatings for the improve- ment of technologies that convert solar energy into heat and electricity opens interesting new perspectives for the future. This PhD thesis presents an approach based on iterative cycles for the development and optimisation of such materials with a view to industrial scale production. Two ap- plications are investigated : chromium-free black selective coatings for durable thermal solar absorbers and orange coloured interferential filters for photovoltaic collectors with a view to their architectural integration. The first part of this work describes in detail the different production stages of the black selective coating from the preparation of the solutions to the manufacturing of a prototype. According to our study, the optimal coating for stainless steel tubes with a length of two meters is composed of a superposition of thin layers of Cu-Co-Mn-O//Cu- Co-Mn-Si-O//Si-O applied through sol-gel technology and annealed by an innovative induction heating process for which a patent request has been filed. The nanocomposite coating has the advantage of combining the optical properties αsol = 0.93 and εth = 0.12 with durability properties that make it eligible for possible industrialisation. The second part of the thesis describes the production of orange coloured interferen- tial filters applied on photovoltaic collectors through magnetron sputtering, a process for which another patent application has been filed. The obtained samples meet the expectations of the market with regard to such a product with a relative performance reduction of 10 to 15% in comparison with an identical collector without a filter. An in- dustrial prototype of 1190 mm x 412 mm has been produced and is being characterised at the moment these lines are written.

Keywords: Daylighting ; electricity ; energy saving ; buildings ; anidolic reflector ; lightdeflector ; light-duct ; solar protection ; blinds ; visual comfort ; thermal comfort ; seasonal selectivity ; Eclairage naturel ; electricite ; economie d'energie ; bâtiment ; reflecteur anidolique ; deflecteur lumineux ; conduit lumineux ; protection solaire ; store ; confort visuel ; confort thermique ; selectivite saisonniere These Ecole polytechnique federale de Lausanne EPFL, n° 2026 (1999)Faculte de l'environnement naturel, architectural et construitLaboratoire d'energie solaire et physique du bâtimentJury: Raphael Compagnon, Markus Hubbuch, Theo Lasser, Juan Carlos Minano, Claude Morel, Jean-Pierre Stoeckli Public defense: 1999-9-9 Reference doi:10.5075/epfl-thesis-2026Print copy in library catalog Record created on 2005-03-16, modified on 2016-08-08