Abitazioni energeticamente efficienti nel clima mediterraneo : due casi studio

Environmental protection, global warming and waste of energy are issues affecting more and more not only research activities about renewable energy sources to safeguard the environment, but also the engineering field which lately has been moving through the construction of low energy buildings, exploiting nature as much as possible. They are buildings known as the German Passivhaus, “passive house”, and they are called in this way because, in order to guarantee the best indoor comfort, they scarcely use exhaustible energy sources, exploiting the heat insulation and renewable sources as much as possible. It’s not by chance that these buildings are known through a German word, having widespread commonly in the Nordic countries. In Italy, for example, it has been only ten years since few Passivhaus were built, and only in the alpine and pre-alpine context. However, it is also true that there is a sort of impossibility to create “passive houses” in hotter climatic contexts because these buildings have a problem with hot temperatures due to the low thermal inertia and to the related lag. We started from the assumption that the environment needs these houses and that’s why they should be developed so as to fit also to temperate and hotter climates to increase the number of implementation all over the world. During academic courses, having studied in deep and in detail different types of buildings, we thought to use them within Italy’s borders. As we all know well, the Italian territory has architectural, landscape and climatic differences and for these reasons we extended the issue trying to understand if, and how, a Passivhaus could work in a hot climate. At this point, we decided to study two isolated single-family buildings, similar for surfaces and volumes, but different for their technologies, systems and architecture, in order to have a better comparison in results; these differences have been developed and emphasized during the numerical evaluations in order to place the single unit properly in the climatic- geographical context. Therefore, we needed two places presenting very marked characteristics and differences so as to be able to obtain very significant results from our experience. Considering our personal origins and the ones acquired over time, we chose to focus our analysis in Lombardia, in particular in Malnago, a hamlet of Lecco; the other location selected for our feasibility study is Rocca Imperiale in Calabria, a town located on the Ionian coast in the high Cosentino. Analyzing in detail the climatic situation of the two sites, important differences emerged so the choice was perfect for our needs to emphasize the problem "Passivhaus in the Mediterranean". Among the differences, these are highlighted: maximum and minimum temperatures, solar radiation, wind course and humidity that have a significant impact on the development and bioclimatic design; these are all environmental- climatic characteristics that determine what can be defined as architectural choices, of interior layout, technological choices, equipments and so on. Obviously taking into account the methods of "design in an energy efficient way", such as the orientation in relation to the solar path, the study of its shading, the exploitation of natural ventilation, therefore, we tried to take the best solutions to build a house where you can live with comfort, where you can relax with a book in your hand in front of a breathtaking view. Next to all these scientific-technological assessments, we tried to juxtapose an ergotechnical design, an engineered project that led to evaluate also the construction variables, the storage of materials and the reduction of construction scraps, but above all that defined possible assembly sequences, timing and methods of production in order to assess better safety of the workplace, too. Proceeding in a parallel way with all these assessments, we defined several technological packages, assuming as a mandatory point the safety and modifying, if necessary, times and costs. Doing so, we tried to fill the different roles orbiting around the building process, to which our study course prepared us, as: designer, developer, CSP. It was a slow and laborious process that led us to define in detail the whole living unit, which during the design underwent many changes dictated by "passive" choices. The results we obtained are very significant and we hope that they can be useful in the very near future for a sustainable design without waste of neither materials nor energy, an issue which today represents a serious global threat. This study was very ambitious: starting from the environmental issue and especially from the issue of the high consumptions in summer, produced also by a bad design, we tried to summarize and organize all the knowledge acquired in the university career within two volumes. The first volume is designed to collect, after a brief introduction, the entire project, the solutions adopted, descriptions and conclusions; the second volume, on the other hand, contains the entire theoretical and legislative part. It is a sort of easy and efficient handbook of sustainable design that can help designers of all generations, using the final summary files that, according to some general data about the geographical and climatic environment, suggest shapes, materials, technologies, equipments and so on. more suitable to the comfort and to savings. They are files that directly compare the two projects and allow a faster and more direct comprehension.

La tutela dell’ambiente, il surriscaldamento del pianeta, lo “spreco” di energia sono problematiche che sempre più interessano non solo le attività di ricerca, riguardo le fonti energetiche rinnovabili per salvaguardare l’ambiente ma anche il campo dell’ingegneria, che negli ultimi anni si è mossa attraverso la realizzazione di edifici a basso consumo, sfruttando il più possibile la natura. Si tratta di edifici conosciuti col nome tedesco di Passivhaus. Noi siamo partiti dal presupposto che queste abitazioni occorrono all’ambiente, quindi andrebbero sviluppate in modo da adattarle anche a climi più caldi. Come ben sappiamo il territorio italiano spazia di lungo e in largo, con una diversità architettonica, paesaggistica, climatica, ecc; per questi motivi si estende la problematica cercando di capire se, e come potesse funzionare una passivhaus in un clima “caldo”. A questo punto si è pensato di studiare due edifici unifamiliari simili dal punto di vista delle superfici e dei volumi, ma tecnologicamente, impiantisticamente e architettonicamente differenti, per poter meglio confrontare i risultati; differenze che si son sviluppate e accentuate nel corso delle valutazioni numeriche per poter meglio inserire nel contesto climatico-geografico la singola unità. Tra le diversità si evidenziano: temperature massime e minime, radiazione solare, andamento dei venti e umidità che incidono in modo significativo sullo sviluppo e la progettazione bioclimatica; tutti caratteri ambientali-climatici che determinano quelle che possiamo definire scelte architettoniche, di disposizione interna, scelte tecnologiche, impiantistiche ecc.