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The nodal role played by the existing city, in relation to the rate of growth of the urbanized population and the historical-architectural and functional value, confronts us with the need to develop new practices of energy requalification of the already built urban fabric.As demonstrated by the UN-Habitat agency, the rate of increase of CO2 and the urban heat island effect are two of the main problems determining the climate change of our planet. The urban fabric, as an anthropogenic product and a complex system that absorbs energy and transforms it, is the most influential element on both dynamics. In particular, the huge energy consumption and the disproportionate use of non-renewable energy sources within the city are considered the main factors in the manifestation of climate consequences. In particular, the building heritage of the consolidated city represents a component of the urban organism particularly influential in the overall budget, and therefore requires careful and timely actions of energy rehabilitation.Although many scientific studies have found the need to adopt systemic approaches, the current global policies for the management of energy consumption of the existing city are mainly focused on lines of action concerning energy efficiency at the micro-scale, that of the individual building. To date, it is necessary a paradigm shift in the management of energy-environmental interventions, using an interdisciplinary logic. However, little is known about the relationship between urban morphology, microclimate, and energy balance at the scale of the neighborhood.The following work, on a theoretical level, analyzing the studies carried out by the Urban Morphology Institute of Paris, the Senseable city lab of MIT in Boston and the City energy lab of Seoul, aims to highlight the relationship between morphological, climatic and energy parameters at the local scale, in order to identify valid criteria for intervention on the existing city.On this basis, the work establishes a methodology of intervention made operational by the definition of a project of energy redevelopment of a piece of city strongly characterized from the historical, architectural, and morphological point of view: that of the Garden City. The latter, even after the recent vicissitudes related to the CoVid-19 pandemic, is the subject of an emerging revaluation, even before for its social quality, for functional and spatial characters.The design focus will be conducted specifically on two cases of garden cities located in the metropolitan areas of Paris and Rome: the cité jardin du Pré-Saint-Gervais (1927-31, 1932-34 and 1947-52) and the garden city Aniene (1919-24).The methodology, defined through the study, analysis and systematization of the literature considered, is tested on two application cases with the aim of providing a design strategy oriented to the resilience of urban fabric through the reduction of energy consumption and mitigation of microclimatic problems related to it., Le rôle crucial de la ville existante, par rapport au taux de croissance de la population urbaine et à sa valeur historique, architecturale et fonctionnelle, nous confronte à la nécessité de développer de nouvelles pratiques pour la requalification énergétique du tissu urbain déjà construit.L’études d'ONU-Habitat ont montré que le taux d'augmentation du CO2 et l'effet d'îlot de chaleur urbain sont deux des principaux problèmes déterminant le changement climatique sur notre planète. Le tissu urbain, en tant que produit fabriqué par l'homme et système complexe qui absorbe l'énergie et la transforme, est l'élément le plus influent dans ces deux dynamiques. En particulier, les énormes dépenses d'énergie et l'utilisation disproportionnée de sources d'énergie non renouvelables dans la ville sont considérées comme les principaux facteurs de la manifestation des conséquences climatiques. En particulier, le patrimoine de la ville consolidée, souvent soumis à une protection architecturale et à des contraintes réglementaires strictes, représente une composante de l'organisme urbain particulièrement influente dans l'équilibre global, et nécessite donc des actions de requalification énergétique attentives et opportunes.Bien que de nombreuses études scientifiques aient montré la nécessité d'adopter des approches systémiques, les politiques globales actuelles de gestion de la consommation d'énergie de la ville existante se concentrent principalement sur l'efficacité énergétique à micro-échelle, pour un seul bâtiment. Aujourd'hui est donc extrêmement nécessaire un changement de paradigme dans la gestion des interventions énergétiques à travers une logique interdisciplinaire. Cependant, on connaît mal la relation entre la morphologie urbaine, le microclimat et le bilan énergétique à l'échelle du quartier.Le travail suivant, sur le plan théorique, en analysant notamment les études réalisées par l'Institut de Morphologie Urbaine de Paris, le Senseable city lab du MIT de Boston et le City energy lab de Séoul, vise à mettre en évidence la relation entre les paramètres morphologiques, climatiques et énergétiques à l'échelle locale, afin d'identifier des critères valables d'intervention dans la ville existante.Sur cette base, le travail établit une méthodologie d'intervention rendue opérationnelle par la définition d'un projet de requalification énergétique d'une partie de la ville fortement caractérisée d'un point de vue historique, architectural et morphologique : la Cité Jardin. Ce dernier, suite également aux récents événements liés à la pandémie de CoVid-19, fait l'objet d'une revalorisation émergente, non seulement pour sa qualité sociale mais aussi pour ses caractéristiques fonctionnelles et spatiales.L'accent sera mis spécifiquement sur deux cas de cités-jardins situées dans les régions métropolitaines de Paris et de Rome : la cité jardin du Pré-Saint-Gervais (1927-31, 1932-34 et 1947-52) et la cité jardin Aniene (1919-24).La méthodologie, définie à travers l'étude, l'analyse et la systématisation de la littérature considérée, est testée sur deux cas applicatifs dans le but de fournir une stratégie de conception orientée vers la résilience du tissu urbain à travers la réduction de la consommation d'énergie et l'atténuation des problèmes microclimatiques qui lui sont liés.

Studiando il lavoro sulle “composizioni alla scala della città” che Antonello Russo ci propone attraverso le elaborazioni dei suoi studenti, appare subito evidente un pensiero sulla forma urbana. Si manifesta l’idea di costruire gli isolati residenziali come singole architetture, nuclei urbani concepiti come un’unica grande casa in cui gli spazi liberi fra gli edifici diventano luoghi del progetto. È in questi spazi che la città rivela il suo intento rappresentativo, che si rende riconoscibile, che diventa teatro della vita degli uomini. Il libro di Antonello Russo è testimone di un’idea di città in cui sono contenute le aspirazioni di una moderna cultura dell’abitare, un’idea di spazio dove poter ritrovare una nuova dimensione “sociale”. Studying the work on the "compositions at the scale of the city" that Antonello Russo proposes to us through the elaborations of his students, a thought on the urban form immediately becomes evident. It manifests the idea of building residential blocks as individual architectures, urban nuclei conceived as a single large house in which the free spaces between the buildings become places of the project. It is in these spaces that the city reveals its representative intent, which becomes recognizable, which becomes the theater of human life. The book by Antonello Russo bears witness to an idea of a city in which are contained the aspirations of a modern culture of living, an idea of space where you can find a new "social" dimension.

The urban space can be considered lively when things happen there: a lot of people move around generating chances for interaction and for economic and cultural activities. Urban vitality consists thus in the very essence of the city in its ancestral meaning of an active community of individuals, which has been too often put aside by modern and contemporary urban reflections and design proposals. The current time of crisis of the collective realm, the virtualization of interpersonal relations and the attention to the global scale instead of the local one lead to ask what it will be of the urban everyday life, especially regarding its most basic declinations such as the proximity relations. The human activity in the cities – as Jan Gehl reminds us – is conditioned by a number of factors, many of which have to do with the environmental and behavioral sphere. A major set of conditioning factors, however, has to do with the fisical and relational configuration of the city. The relation between the fisical characters of the city and the expression of the urban life can be traced by analyzing the form of the city and its topological features with an appropriate metodology, as well as scientifically observing the way people act in the urban space. Finding out about how deep can a set of characters of the urban form influence vitality can result in an enormously useful tool for the development of new urban areas as well as for the requalification of existing dull neighbourhoods, a task many western cities are nowadays called to answer to.

This research aims at exploring meanings, qualities and analytical abilities of density concept and its potential interpretations in architecture and sustainability fields. Despite the growing unsustainability of today's city facing an effective energy and environmental crisis, recent statistics have confirmed the increasing attractive power of metropolitan areas. Within the context of European compact city, new building models based on energy conservation principles account for an insignificant percentage compared to the great mass of existing city whose functioning remarkably affects the inefficiency of the whole metropolitan system. Therefore an approach determining design instruments and methods at urban and architectural scale must be found in order to set out conditions more appropriate to the compact city. At this analysis stage, the relationship between energy and form takes a central role in the variation of energy performances; at the same time the concept of density has showed the ability to describe the morphological performances of the built form. The general aim of the present research is to determine the relationships among built-form, energy and urban fabrics by the density parameter in compact city with Mediterranean climate. This research is composed by four interconnected parts. The first one examines the relationship among current urban and energy dynamics to comprehend the role and contribution of the building industry in the light of the scientific progress and the implementation of present operational and regulatory instruments. The second one investigates role and evolution of the density concept as parameter, design instrument and basis of theoretical categories, especially referring to interactions with urban form and sustainability. In the third part the analytical and interpretative abilities of density are employed in order to prove the environmental implications and verify the existence of interactions among urban sustainability indicators and density. Finally, the fourth part enquires into the relationships among form, building, density and energy set up in the compact fabrics in Rome and Barcelona by models and simulations in order to control the main formal, building and energy factors parametrically. The influence of urban morphology, built-form and constructive features on solar access and energy demand for conditioning are shown by different density indicators that are the more suitable to express reliable trends. Firstly results point out that the contribution of the built environment to the complex energy issue arisen by metropolitan systems must be focused on the reduction of the demand - even before on the consumption and impact - operating with multi-scale instruments and methods for the transformation of existing city. The density has a preferred role in the relationship between sustainability and form thanks to its interpretative skills and meanings undertaken as theoretical and design category. At the metropolitan scale, urban quality indicators and density do not always show evident relationships with energy and environmental implications. Built-form typology and constructive features are the main factors that occur on energy performances variation of urban fabrics. The investigation of these kind of performances by density parameters leads to the comprehension of the different energy behavior in each urban texture, offering a contribution to the energy analysis at urban scale. Methodology and the defined parameters of density show themselves as knowledge base for aware transformations of Mediterranean compact city as well as applications in other urban contexts both for existing and new constructions., La ricerca esplora significati, proprietà e capacità analitiche del concetto di densità e delle sue possibili interpretazioni nell’ambito dell’architettura e della sostenibilità. Il suo obiettivo è la determinazione di relazioni tra costruito, energia e forma dei tessuti urbani della città compatta mediterranea ricorrendo alla densità quale parametro utile a decifrarne le specificità. A dispetto della sempre maggiore insostenibilità della città odierna, di fronte alla crisi energetica ed ambientale in atto, recenti statistiche hanno confermato il crescente potere attrattivo delle aree metropolitane. Nel contesto della città compatta europea, i nuovi modelli insediativi basati su principi di risparmio energetico rappresentano una percentuale insignificante rispetto alla città esistente che, nel funzionare, incide notevolmente sull’inefficienza dell’intero sistema metropolitano. In questo quadro, potrebbe essere risolutivo identificare un approccio che individui strumenti e metodi progettuali alla scala urbana piuttosto che a quella architettonica, utili a definire condizioni più appropriate e realmente incisivi per la città compatta. Se riferito in primo luogo a tale scala il rapporto tra energia e forma assume un ruolo centrale sulla variazione delle prestazioni energetiche; allo stesso tempo il concetto di densità appare un’efficace strumento di analisi delle prestazioni morfologiche del costruito. La ricerca si compone di cinque parti. La prima analizza la condizione odierna delle dinamiche urbane ed energetiche, per comprendere ruolo e contributo dell’edilizia alla luce dell’avanzamento del pensiero scientifico e degli strumenti operativi disponibili. La seconda affronta il significato e l’evoluzione del concetto di densità quale parametro di misura, strumento progettuale e fondamento teorico, facendo riferimento in particolare alle interazioni con la forma urbana e la sostenibilità. Nella terza si utilizzano le capacità analitiche della densità per comprovare le implicazioni ambientali e verificare l’esistenza di leggi di dipendenza tra indicatori di sostenibilità urbana e densità. La quarta pone le basi per la comprensione delle relazioni tra densità ed energia alla scala urbana. La quinta parte, infine, indaga tali relazioni nei tessuti compatti di Roma e Barcellona declinandole in termini di caratteri formali e costruttivi, con l’ausilio di modellazioni e simulazioni strutturate allo scopo di controllare i corrispondenti fattori. S’illustra l’influenza di morfologia urbana e caratteri tipologico-costruttivi su guadagno solare e domanda energetica per riscaldamento e climatizzazione, individuando per mezzo di differenti definizioni d’indicatori di densità, i più adeguati ad esprimere con queste leggi di variazione affidabili. I risultati evidenziano che il contributo dell’edilizia alla complessa questione energetica posta dai sistemi metropolitani deve concentrarsi sulla riduzione della domanda - ancor prima che su consumo e impatto - operando con strumenti e metodi interscalari per la trasformazione della città esistente. La densità ha un ruolo privilegiato nel rapporto forma-sostenibilità per capacità interpretative e significati assunti quale categoria teorica e progettuale. A scala metropolitana, indicatori di sostenibilità urbana e densità non sempre mostrano chiare relazioni con le implicazioni ambientali ed energetiche. Morfologia, tipologia e aspetti costruttivi sono i fattori che più intervengono sulla variazione delle prestazioni energetiche dei tessuti urbani. Analizzarli mediante parametri di densità conduce alla comprensione del diverso comportamento energetico, fornendo un contributo agli strumenti d’indagine a scala urbana e favorendo una connotazione più efficiente del costruito riconducibile alla dimensione della densità sostenibile. Il metodo e gli strumenti individuati si offrono come base di conoscenza per trasformazioni consapevoli della città compatta mediterranea, El presente estudio indaga significados, propiedad y capacidad analíticas del concepto de densidad y de su posible interpretación en el ámbito de la arquitectura y de la sostenibilidad. El principal objetivo es determinar las relaciones entre ambiente construido, energía y forma de los tejidos urbanos recurriendo a la densidad como parámetro útil para descifrar sus especificidades de la ciudad compacta mediterránea. A pesar de una siempre mayor insostenibilidad de la ciudad actual, frente a la crisis energética y ambiental en curso, estadísticas recientes han confirmado el creciente poder atractivo de las metrópolis. En el contexto de la ciudad europea, los modelos de asentamiento actuales, basados en principios de ahorro energético, constituyen un porcentaje insignificante frente a la ciudad existente que, funcionando, grava notablemente en consumo el sistema metropolitano. En esta situación, podría ser resolutivo identificar un acercamiento que identifique herramientas y métodos para el proyecto a escala urbana, que sean útiles para definir condiciones más apropiadas y sean realmente eficaces para la ciudad compacta. Si se refiere en primer lugar a dicha escala, la relación entre energía y forma asume una función central para la variabilidad de la prestación energética; al mismo tiempo el concepto de densidad parece una herramienta eficaz para analizar las prestaciones morfológicas del ambiente construido. La investigación se compone de cinco partes. La primera analiza las dinámicas urbanas y energéticas actuales, para entender capacidad y contribución de la construcción a la luz del avance del pensamiento científico y de las herramientas disponibles. La segunda trata el significado y la evolución del concepto de densidad como parámetro de medida, herramienta del proyecto y origen teórico de la arquitectura, con particular referencia a las interacciones con la forma urbana y la sostenibilidad. En la tercera se utilizan las capacidades analíticas de la densidad para comprobar las repercusiones ambientales y verificar la existencia de leyes de dependencia entre indicadores de sostenibilidad urbana y densidad. La cuarta explica las relaciones entre densidad y energía a la escala urbana. La quinta, finalmente, estudia estas relaciones en los tejidos compactos de Roma y Barcelona, explicándolas en función de forma i construcción, con el auxilio de modelos y simulaciones. Se muestra la influencia de la morfología urbana y las características tipológicas y constructivas sobre la captación solar y la demanda energética por calefacción y climatización, individualizando entre diferentes indicadores de densidad los más apropiados para representar tendencias fiables. Los resultados prueban que la contribución de la construcción a la compleja cuestión energética tiene que basarse en la reducción de la demanda - antes que del consumo y del impacto - utilizando herramientas y métodos multi-escalares para la transformación de la ciudad existente. La densidad tiene una función privilegiada en la relación forma-sostenibilidad que depende de sus capacidades analíticas y significados en calidad de categoría teórica y del proyecto. A escala metropolitana, los indicadores de sostenibilidad urbana y densidad no siempre muestran una relación clara con las repercusiones ambientales y energéticas. Morfología, tipología y aspectos constructivos son los factores que más influyen sobre la variación de la prestación energética de los tejidos urbanos. Analizarlos recurriendo a parámetros de densidad, lleva a entender el diferente comportamiento energético, contribuye a las investigaciones a escala urbana y favorece la eficiencia del ambiente construido, con lo cual se reconduce el análisis al concepto de densidad sostenible. La metodología y las herramientas individualizadas se ofrecen como base de conocimiento para orientar las transformaciones de la ciudad compacta mediterránea.

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