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The paper outlines the evolution of solar architecture in the past 80 years. The goal is to consider the study of the morphology of architecture in its relationship with services, especially solar active systems; our purpose is to enhance the idea that history of services should help achieving efficiency targets in buildings. In this actual phase of massive production of active systems, a real integration is not always the final result of building design. The interpretation of the controversial term “solar architecture” is based on some milestone books in the United States and Europe over the last 80 years. With active solar architecture it is intended the exploitation of solar radiation with the use of mechanical systems (services), that are preferably integrated in the building. On the contrary, passive systems (greenhouses, etc..) don’t use mechanical systems, but exploit solar radiation (minimizing overheating) through architectural components, considering the shape and the orientation of the building. The first known example of active solar house can be found in Cambridge (USA) in 1939; the Solar House I was built at MIT to test an original thermal solar system, compatible with the morphology of a common American House; the water was heated in panels placed on the roof, then stored in a boiler underground, where the thermal energy of the fluid was exchanged with the cooler air of a pipe system; the temperate air was finally sent inside the house using some ventilators. After the Second World War the experiments at MIT continued (Solar II, III, IV, …). The houses in Cambridge proved that active buildings could no longer exist without the integration with passive systems. Passive and active systems found a very high level of integration after the oil crisis (1973), in particular in Germany with the work of Thomas Herzog. The recent development of PVs has encouraged the integration of active systems in many prototype buildings in Europe and United States. A small selection of built examples in this paper show a new reconsideration of the role of the building envelope. Its function of energy exchanger is assuming a relevant position in the general economy of the project. All that influences the formal composition in an architectural design. The conscious choice to operate with the instruments of solar architecture imply very precise results, directing the project to a maximum level of energy efficiency in relation to an high level of architectural quality: this relation can be defined as synergic efficiency.

The very actual theme of building stock retrofit includes wide ranges of possible actions, especially in social housing. Multi-criteria assessments should be lead to evaluate the proper operational approach (considering social, structural, maintenance, thermal and economic parameters). The lower-impact actions typically involve improvements on the building skin, such as insulation and window re-placement, while the higher-impact solutions lead to demolition and re-building. Overall, building retrofit through solar technologies represents a relevant strategy to achieve significant energy saving. In this context two comparative solutions have been proposed for an early ‘80s social building in Modena. The former consists in the ap-plication of passive systems to optimise solar gains and active tech-nologies to generate energy. The latter is based on demolition and re-building of a newly designed block according to best practice princi-ples. The performance of solar strategies efficiency has been evaluated through parametric markers, while multizone thermodynamic and CFD analysis have been used to estimate the effects of passive cooling technologies.

La recente Direttiva 31/2010 dell’Unione Europea impone agli stati membri di riorganizzare il quadro legislativo nazionale in materia di prestazione energetica degli edifici, affinchè tutte le nuove costruzioni presentino dal 1° gennaio 2021 un bilancio energetico tendente allo zero; termine peraltro anticipato al 1° gennaio 2019 per gli edifici pubblici. La concezione di edifici a energia “quasi” zero (nZEB) parte dal presupposto di un involucro energeticamente di standard passivo per arrivare a compensare, attraverso la produzione preferibilmente in sito di energia da fonti rinnovabili, gli esigui consumi richiesti su base annuale. In quest’ottica la riconsiderazione delle potenzialità dell’architettura solare individua degli strumenti concreti e delle valide metodologie per supportare la progettazione di involucri sempre più performanti che sfruttino pienamente una risorsa inesauribile, diffusa e alla portata di tutti come quella solare. Tutto ciò in considerazione anche della non più procrastinabile necessità di ridurre il carico energetico imputabile agli edifici, responsabili come noto di oltre il 40% dei consumi mondiali e del 24% delle emissioni di gas climalteranti. Secondo queste premesse la ricerca pone come centrale il tema dell’integrazione dei sistemi di guadagno termico, cosiddetti passivi, e di produzione energetica, cosiddetti attivi, da fonte solare nell’involucro architettonico. Il percorso sia analitico che operativo effettuato si è posto la finalità di fornire degli strumenti metodologici e pratici al progetto dell’architettura, bisognoso di un nuovo approccio integrato mirato al raggiungimento degli obiettivi di risparmio energetico. Attraverso una ricognizione generale del concetto di architettura solare e dei presupposti teorici e terminologici che stanno alla base della stessa, la ricerca ha prefigurato tre tipologie di esito finale: una codificazione delle morfologie ricorrenti nelle realizzazioni solari, un’analisi comparata del rendimento solare nelle principali aggregazioni tipologiche edilizie e una parte importante di verifica progettuale dove sono stati applicati gli assunti delle categorie precedenti, The recent Directive 31/2010 of the European Union requires that the member states reorganize their national legislative framework in the field of energy performance of buildings. so that from 1 January 2021 the energy balance of all new buildings will tend to zero (1 January 2019 for public buildings). The concept of nearly Zero Energy Buildings (nZEB) is based on the assumption that the envelope follows the standard of the passive houses and the small energy consumption required on annual basis is compensated by the production of renewable energy, preferably on-site. In this context, the rethinking of the potential of solar architecture allows to identify concrete tools and valid methodologies to support the design of increasingly efficient envelopes that take full advantage of an inexhaustible, common and affordable energy source, such as the solar energy. This should be achieved considering the necessity of no longer delaying the reduction of the energy load due to buildings, known as responsible for over 40% of world consumption and 24% of greenhouse gas emissions. According to these premises, the central theme of the research is the integration of the heat gain systems, so-called passive, and the solar energy production, so-called active, in the envelope. The carried out analytical and operational path has set the objective of providing practical and methodological tools for the design of the architecture, in need of a new integrated approach to achieve the goals of energy savings. Through a general survey of the concept of solar architecture and its theoretical assumptions and terminology, the research has envisioned three types of outcome: a codification of the recurring morphologies in solar constructions, a comparative analysis of the solar performance in the principal types of building aggregations and a significant design verification, where the assumptions of the previous categories have been applied

Zero Energy Buildings require airtightness and mechanical ventilation systems to provide air changes and energy saving. These requirements contrast with the principles of natural ventilation. Through a case study located in Modena, Italy, a design strategy is proposed as a solution to integrate natural and mechanical ventilation systems at different times of the year to reduce the energy consumption in a newly designed high-density ZEB. The internal comfort evaluation for the warm season is then verified with a multizone dynamic simulation and a CFD analysis. The proposal consists of two different approaches, the cold season and the warm one. For the cold season, a mechanical ventilation system with earth tubes and heat recovery has been designed, together with airtightness, solar greenhouses and high thermal mass and insulation. For the warm season the design allows a free-running use: open trickle ventilators applied to windows which provide background ventilation, mass and insulation mitigate the heat loads, vertical ventilation shafts support natural ventilation and free night cooling. The ventilation shafts have been designed with aerodynamic principles to provide each apartment with additional (and maximised) differences of pressure due to the stack effect. The indoor comfort conditions in the warm season are then evaluated according to the ASHRAE 55 adaptive model for free-running buildings. The results of the study confirm that in the warm season acceptable indoor comfort conditions can be achieved in a free running building. The ventilation shaft has

La recente Direttiva 31/2010 dell’Unione Europea impone agli stati membri di riorganizzare il quadro legislativo nazionale in materia di prestazione energetica degli edifici, affinchè tutte le nuove costruzioni presentino dal 1° gennaio 2021 un bilancio energetico tendente allo zero; termine peraltro anticipato al 1° gennaio 2019 per gli edifici pubblici. La concezione di edifici a energia “quasi” zero (nZEB) parte dal presupposto di un involucro energeticamente di standard passivo per arrivare a compensare, attraverso la produzione preferibilmente in sito di energia da fonti rinnovabili, gli esigui consumi richiesti su base annuale. In quest’ottica la riconsiderazione delle potenzialità dell’architettura solare individua degli strumenti concreti e delle valide metodologie per supportare la progettazione di involucri sempre più performanti che sfruttino pienamente una risorsa inesauribile, diffusa e alla portata di tutti come quella solare. Tutto ciò in considerazione anche della non più procrastinabile necessità di ridurre il carico energetico imputabile agli edifici, responsabili come noto di oltre il 40% dei consumi mondiali e del 24% delle emissioni di gas climalteranti. Secondo queste premesse la ricerca pone come centrale il tema dell’integrazione dei sistemi di guadagno termico, cosiddetti passivi, e di produzione energetica, cosiddetti attivi, da fonte solare nell’involucro architettonico. Il percorso sia analitico che operativo effettuato si è posto la finalità di fornire degli strumenti metodologici e pratici al progetto dell’architettura, bisognoso di un nuovo approccio integrato mirato al raggiungimento degli obiettivi di risparmio energetico. Attraverso una ricognizione generale del concetto di architettura solare e dei presupposti teorici e terminologici che stanno alla base della stessa, la ricerca ha prefigurato tre tipologie di esito finale: una codificazione delle morfologie ricorrenti nelle realizzazioni solari, un’analisi comparata del rendimento solare nelle principali aggregazioni tipologiche edilizie e una parte importante di verifica progettuale dove sono stati applicati gli assunti delle categorie precedenti, The recent Directive 31/2010 of the European Union requires that the member states reorganize their national legislative framework in the field of energy performance of buildings. so that from 1 January 2021 the energy balance of all new buildings will tend to zero (1 January 2019 for public buildings). The concept of nearly Zero Energy Buildings (nZEB) is based on the assumption that the envelope follows the standard of the passive houses and the small energy consumption required on annual basis is compensated by the production of renewable energy, preferably on-site. In this context, the rethinking of the potential of solar architecture allows to identify concrete tools and valid methodologies to support the design of increasingly efficient envelopes that take full advantage of an inexhaustible, common and affordable energy source, such as the solar energy. This should be achieved considering the necessity of no longer delaying the reduction of the energy load due to buildings, known as responsible for over 40% of world consumption and 24% of greenhouse gas emissions. According to these premises, the central theme of the research is the integration of the heat gain systems, so-called passive, and the solar energy production, so-called active, in the envelope. The carried out analytical and operational path has set the objective of providing practical and methodological tools for the design of the architecture, in need of a new integrated approach to achieve the goals of energy savings. Through a general survey of the concept of solar architecture and its theoretical assumptions and terminology, the research has envisioned three types of outcome: a codification of the recurring morphologies in solar constructions, a comparative analysis of the solar performance in the principal types of building aggregations and a significant design verification, where the assumptions of the previous categories have been applied

L’idea di proporre un osservatorio sulla qualità edilizia è nata dall’intento di fotografare in modo critico quello che viene costruito in un certo lasso di tempo all’interno di un determinato ambito territoriale, estrapolando le problematiche in atto e le tendenze per il prossimo futuro. Nell’attuale rapporto sempre più dicotomico tra teoria e pratica del progetto, l’obiettivo è stato quello di mettere in evidenza lo stato dell’arte della pratica progettuale, che si concretizza nel costruire contemporaneo, riferita ad alcune tipologie edilizie e perimetrate volutamente in un preciso ambito territoriale di riferimento. Lo studio condotto per il territorio romagnolo ha analizzato più di centocinquanta “progetti costruiti” nelle provincie di Forlì-Cesena, Ravenna, Rimini dal 2008 al 2013; sono stati indagati i vari tipi di intervento in rapporto ad alcuni aspetti fondamentali come la relazione con il contesto ambientale, le dinamiche del progetto e della costruzione, la scelta dei prodotti e dei sistemi edilizi. In alcuni casi l’indagine è stata estesa ad alcune porzioni del territorio delle provincie di Bologna e Ferrara, storicamente vicine alla Romagna dal punto di vista culturale e costruttivo. Questo osservatorio vorrebbe essere il primo capitolo di un lavoro di analisi sull’attività edilizia da monitorare in successivi step temporali e sintetizzata periodicamente, in modo da delineare un originale quadro conoscitivo nel medio-lungo periodo, proponendo al contempo una precisa metodologia di analisi del costruito ricompreso in undeterminato ambito territoriale. Il lavoro si è basato su progetti di edilizia prevalentemente privata sparsi nel territorio romagnolo e scelti in base alla possibilità di reperire il materiale tecnico fornito direttamente dai progettisti. Il reperimento dei documenti non sarebbe stato possibile in un luogo diverso da quello universitario attraverso l’azione fattiva degli studenti. L’ambito di analisi ha considerato le varie fasi del progetto architettonico

The research derives from an agreement between ACER (Azienda Casa Emilia-Romagna) and the University of Bologna with the aim of defining a set of guidelines for the recovery and the efficiency of the social housing stock in the province of Modena. The analysis of buildings in state of functional decay and especially structural and energy inadequacy is directed to the development of intervention strategies according to maintenance and performance levels. The case study at issue is a 93-units apartment building erected in the 80s and now evaluated for its renovation (phase A) or demolition and reconstruction (phase B).

Resoconto tecnico-emozionale degli effetti del sisma, del maggio 2012, sulle architetture locali. Il breve saggio è stato elaborato dopo alcuni viaggi nei territori di Finale Emilia e Mirandola nell'autunno del 2012, finalizzati alla realizzazione della mostra "Architetture Padane".

La progettazione dei componenti attivi e passivi d’involucro deve tener conto anche delle scelte sul colore, poiché queste possono influenzare fortemente il rendimento energetico dell’edificio. Un’analisi dei componenti passivi dell’involucro edilizio e delle implicazioni in termini di “risposta energetica” dello stesso. La temperatura raggiunta dalla superficie di un involucro opaco esposto al sole determina la quantità di calore che può successivamente entrare all’interno dell’edificio. Un primo aspetto da considerare nella progettazione cromatica di un edificio riguarda dunque la capacità di assorbimento della radiazione da parte dell’involucro opaco, valutata attraverso il coefficiente di assorbimento. La riflettanza solare – simile al concetto di emissività – invece rappresenta la frazione di radiazione solare incidente direttamente riflessa da una superficie irradiata.Ai fini della riduzione della temperatura superficiale è quindi consigliabile utilizzare prodotti con basso valore di assorbimento ed alto valore di riflettanza, come auspicato in Italia anche dalla norma UNI-TS 11300-1:2008 sull’efficienza energetica. Nell'articolo sono considerati vari prodotti e varie soluzioni tecniche, sia per le superfici opache verticali e di copertura che per le componenti vetrate.

Nella progettazione architettonica le scelte cromatiche derivano prevalentemente da ragioni estetiche, sebbene abbiano implicazioni dirette sull’efficienza energetica dell’edificio. Nel recente passato quest’aspetto è stato spesso trascurato. Oggi l’applicazione dei concetti legati all’efficienza energetica sta condizionando la colorazione degli edifici, soprattutto delle coperture, con risultanze cromatiche non del tutto controllate e a volte non attese. Da una parte l’introduzione di nuovi componenti solari attivi, come i pannelli fotovoltaici (FV), ha mutato drasticamente la resa cromatica degli involucri richiedendo riflessioni approfondite sul concetto di progetto integrato. Dall’altra si è sviluppata l’idea che la colorazione dei componenti d’involucro costituisca un fattore influente sul rendimento energetico complessivo degli edifici. In definitiva, il progetto di tali componenti richiede oggi un’analisi accurata delle caratteristiche cromatiche. Questo contributo si propone di offrire alcune riflessioni progettuali in ambito architettonico sul rapporto tra l’efficienza energetica di componenti solari attivi – cioè impiantistici – e passivi di involucro e il colore, considerato secondo parametri opportuni.

In the Italian region of Emilia-Romagna the economic growth of the Fifities – the so-called economic boom – was based on industrial production, mostly generated by the initiative of small size craftsman cooperatives. The model of development, with strong social character, was based on the initiative of the public administration, that had the political and economical power to trade rural areas at the boundaries of the city and sell them at a very low cost to the new enterprises. After fifty years or relative success, that economic model is facing an economic crisis, due to the globalization of the markets, that is forcing the reallocation of many small and medium sized enterprises in bigger industrial areas or, even, their collapse. Part of the old semi-industrial areas located within the boundaries of the city, are now partially dismissed. In order to regenerate the functionality of these obsolete industrial districts, new strategies are required, based on the promotion of private investments. According to the expectations of the promoters, new guidelines for the reconfiguration of the districts and more flexible urban rules should help in trying to regenerate the areas with the aim of creating new poles for highly specialized craft, creativity and technological innovation. The new initiatives for the regeneration of the districts try to match new functions with high environmental standards (eco-design, green buildings). In this paper we analyze a recent initiative of the city administration for the regeneration of a semi-industrial area in Modena, named villaggio artigiano. This process is based on functional mixité, that is considered a strong antidote to urban sprawl and the urban zoning of the Modern Movement that has separated housing, work places, shops and services. The original structure of the villaggio should be able to facilitate this process of regeneration and reappropriation of public space, based on the technological aspects of architectural design and the potentialities of energy rehabilitation and on-site energy production. The aim is to reach the goal of a zero energy district. This initiative has been widely promoted – the district and its enterprises have their own Web page – and it is supported by some architectural proposals derived from inter-disciplinary workshops that involved many professionals and the University of Bologna.

In Europe many city governments have recently promoted participative processes for urban rehabilitation. Participation is an efficient and politically correct way not only to support new ideas and strategies for urban transformations, but also to improve the environmental consciousness of social groups. Awareness of ecological issues, supported by participation, and promotion of urban quality converge in an unique task. Controlling urban transformations has more and more become an extremely complicated task for local administrations, due to the fragmentation of the public institutions, the unexpected political conflicts and the lack of public financial resources in comparison with private capitals. In this general frame the case study of Villaggio Artigiano in Montreal has been presented.

In this paper a design strategy is presented to integrate energy efficiency measures and passive energy use, in order to meet near Zero Energy Buildings requirements in European temperate climates. In particular, a hybrid system for the integration of natural and mechanical ventilation at different times of the year is proposed. ZEBs and nZEBs usually employ mechanical ventilation systems to provide air changes and energy saving. This common solution is in contrast with the principles of natural ventilation and adaptive comfort. It is well known that natural ventilation can significantly reduce the energy demand during the summer. The case study is represented by a social housing complex located in the periphery of Modena (Italy), dating back to 1980. The project consists in the deep energy renovation of some buildings of this complex to accomplish nZEB standards. The proposal envisages two different modes of operation for the buildings, one for the cold season and one the warm season. For the cold season, a mechanical ventilation system with earth tubes and heat recovery has been designed, together with airtightness, solar greenhouses and high thermal mass and insulation. For the warm season the design allows a free-running use: open trickle ventilators applied to windows which provide background ventilation, mass and insulation mitigate the heat loads, vertical ventilation shafts support natural ventilation and free night cooling. The ventilation shafts are designed with aerodynamic principles to provide each apartment with additional (and maximised) differences of pressure due to the stack effect. The ventilation shafts have an important role for the free cooling. The renovated buildings are also equipped with active systems to compensate the remaining energy demand: a Combined Heating Power System (CHP), PV panels and solar thermal collectors. The indoor comfort conditions in the warm season are evaluated according to the ASHRAE 55 adaptive model for free-running buildings. The internal comfort in the warm season is verified with a multizone dynamic simulation and a CFD analysis. The results of the study confirm that in the warm season acceptable indoor comfort conditions can be achieved in a free running nZEB.