Parte 2. Analisi delle stratigrafie

La pubblicazione si compone di tre sezioni, completate da un’appendice contenente esempi di calcolo. La prima parte illustra, attraverso schede operative di agevole consultazione, una metodologia di approccio innovativo al problema della riqualificazione energetica dell’edilizia residenziale esistente. La seconda sezione propone una raccolta di schede come strumento di consultazione delle prestazioni termiche relative a un campione di elementi costruttivi, in grado di fornire un riferimento operativo utile per impostare un intervento di riqualificazione volto a migliorare l’efficienza energetica dell’involucro edilizio. Le schede stratigrafiche riportano i materiali che compongono i singoli elementi costruttivi presi in esame, analizzano la possibilità di isolamento sia dall’interno che dall’interno, prendendo in considerazione materiali isolanti di diversa natura. Oltre all’indicazione delle caratteristiche termo-fisiche dei materiali e delle prestazioni termiche, in periodo invernale ed estivo, particolare attenzione è rivolta all’andamento del contenuto di umidità all’interno dell’elemento costruttivo in regime non stazionario, riportando i grafici che illustrano la situazione che si verifica nei tre anni successivi all’intervento di risanamento. La terza sezione illustra i principali nodi costruttivi presenti in una tipologia costruttiva diffusa nel patrimonio edilizio esistente, suggerendo soluzioni di intervento, presentando le difficoltà e fornendo consigli pratici per la progettazione. Partendo dal dettaglio del nodo esaminato, si prendono in esame i punti critici ed i problemi particolari, precisando ciò che è importante conoscere durante la progettazione e la messa in opera. L’approccio adottato può essere utilizzato nel caso di altre tecnologie e i principi esplicati nel caso illustrato possono essere estesi anche ad altre tipologie

A new approach to energetic requalification of existing buildings

A good knowledge of technical features of existing building resources is necessary to improve their energetic performances. For this purpose the research analyses building systems and technologies and it identifies energetic problems and performances, proposing a critic evaluation of the possibilities of the intervention. The research pays a special attention on moisture and condensation problems which can occur as a consequence of retrofitting interventions. The impact of the planning decisions on moisture content and behaviour of the existing components with respect to building physics have to be taken into consideration when there are attempts to upgrade the building’s thermal performance of existing building to save energy. The verification of moisture transfer is generally conducted using the standardised steady-state Glaser method. This standard calculation, considering only vapour diffusion transfer, fails to produce realistic results when handling with an interior thermal insulation because overestimates the possibility of condensation at the former inner surface of the wall and doesn’t consider the moisture storage potential of the component. In this research an innovative simulation method is used; it is developed to perform more realistic and detailed simulation of the hygrothermal behaviour based on EN 15026:2008. The method allows to evaluate the real potential of interior thermal insulation on existing building components under natural conditions

"Easy Wind Tunnel", a fluid dynamic approach for everyone

Understanding the physics background of natural ventilation is not always easy for architects and designers. For them, during concept phase, the most important question is: “How is it possible to correctly design a windowing system which can improve natural ventilation in buildings?” So, they are not strictly interested to exactly calculate wind flows. In this case it look more suitable to develop some strategies for easily evaluate the problem from a qualitative point of view. This work presents how to create an affordable wind tunnel to develop user-friendly qualitative analysis of simplified models. To improve students skills, it was decided to create a wind tunnel trying to not exceed a maximum budget of 3000 euros. By this way, the instrument created could be a reference prototype easily reproducible for universities and professionals. This prototype was tested for two years, during didactic courses, asking students to interact with it. So, some simplified models were created to test simple ventilation scenarios (e.g. crossing ventilation, bypass ventilation, wind chimney, …). Regarding the results achieved during educational activities, it is possible to consider the wind tunnel as a very useful instrument for students, during didactic courses and thesis phases, or for professionals, to make affordable comparisons between simplified evaluations and CFD calculations

Recalificación energética de la edificación existente

En las politicas para reducir el consumo energético y las emisiones en la construcción, la recalificación energética representa un enorme potencial: los edificios residenciales anteriores a los años 70 representan en Italia más del 65% del patrimonio, con un consumo considerablemente más elevado respecto a las normativas preceptivas. En las nuevas construcciones las normativas, la metodología, la buena práctica y los materiales innovativos pueden garantizar las prestaciones energéticas adecuadas, mientras que en las intervenciones de rehabilitación diversos problemas y complejas variables pueden limitar la posibilidad de la intervención. El estudio propone un cuadro metodológico para verificar la aplicabilidad y la ejecución de las estrategias de reducción energética para las edificacione existentes: sistemas de análisis y de cálculo, técnicas de intervención, materiales, su compatibilidad y dimensiones. El estudio analiza la edificación pública romana del siglo XX, catalogando las intervenciones por época de construcción, sistemas constructivos, tecnologías y tipologías distributivas; a su vez, identifica problemáticas energéticas y prestacionales, proponiendo una valoración crítica de las alternativas de intervención. Propone, a medio plazo, una metodología de proyecto y a corto plazo, un primer elenco de soluciones operativas

Lipid profile, BMI, body fat distribution, and aerobic fitness in men with metabolic syndrome

Obesity, impaired glucose tolerance, type 2 diabetes, hyperlipidemia, hypertension, and insulin resistance are wellknown components of metabolic syndrome and are associated to increased cardiovascular morbidity. The present study aimed to evaluate the relationships between cardiorespiratory fitness, body fat distribution, and selected coronary heart disease risk factors. A total of 22 untrained subjects affected by one or more features of metabolic syndrome and without clinical history of cardiovascular disease were studied. Nondiabetic subjects underwent an oral glucose tolerance test for glucose and insulin measurement; fasting glucose and insulin were measured in diabetic patients. Complete lipid profile, thyroid hormones, and thyroid-stimulating hormone were measured in all subjects. Basal energy expenditure and cardiorespiratory fitness were measured using a K4 analyzer. Cardiorespiratory fitness ( VO(2max)/kg) was assessed using a treadmill graded exercise test. Peak aerobic capacity ( VO(2max)/kg) was predicted by body fat distribution, insulin sensitivity index, and high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol ( p<0.001). A significant relationship was found between cardiorespiratory fitness ( VO(2max)/kg) and body mass index (BMI), insulin sensitivity index, and LDL cholesterol ( r=0.60, p<0.05; r=0.66, p<0.01 and r=0.54, p<0.05, respectively). Data demonstrated that aerobic fitness is related to metabolic parameters and to body fat distribution, and suggest that its modification may improve well-known predictors of coronary artery disease

Timber frame wall with enhanced energy performance - The Solar Decathlon Europe experience

The research focuses on timber frame structures and their weakness regarding their summer behaviour. Timber frame structures, which represent the established standard of the preassembled wooden made houses of small and medium size, perfectly fit to cold weathers with heating requirements during most part of the year. It is demonstrated that they reach the same thermal characteristic, Uvalue transmittance, with the tiniest thickness of boundary wall. Nowadays, the real technical challenge for these wooden structures lies in hot weather conditions and during summer time. As in the last decades the attention has been focused on the reduction of the heating energy needs in steady-state conditions, the envelope dynamic behaviour has been neglected because it is not crucial in the winter period. At the present time, wooden structures in the Mediterranean area suffer the comparison with heavy brick and concrete buildings. The lower thermal capacity decreases the thermal inertia, speeds the dynamic response and therefore seems to be the main cause of the worsening of the indoor comfort. The direct solution which is the increase of the internal mass up to achieving the required levels will lead to an unavoidable growth of the whole structure mass and thence to a decay of its seismic behaviour. Briefly, the answer to one issue will spoil the main characteristic of the timber structures. The need to find such a solution came up to evidence as the Med in Italy group was chosen to participate to the Solar Decathlon Europe 2012 and both Free University of Bolzano-Bozen and Fraunhofer Italia Research were asked for the energy performance consultancy. According to the main purpose of design strategies, the improvement of thermal capacity across envelope elements has been deeply investigated. The main strategy included an increased mass across walls respecting the lightness of structures typical of wood technologies. Therefore some alternative strategies has been investigated starting from a uniform mass distribution. The use of sand as thermal mass represented a big challenge to analyse different mass typologies

Flexibility in energy-efficient public housing as a factor of social. economic and environmental sustainability

The general purpose of this research project is to create a Construction Building Guide for professionals and technicians that could be applied in all climatic zones of Italy by introducing flexibility issues as a new standard. The first part of research is focused to design a prototype of low-cost prefabricated apartment block. The building should include some concepts as: efficiency, flexibility respecting changes in the nuclear family, modularity, high-energy performance and, at the same time, high quality of life and low environmental impact. Moreover, according to family needs, flexibility should allow modifying a dwelling surface and internal functionality by joining together rooms or service without limits on the part of plant engineering. The paradigm of flexibility is strictly linked to modularity and prefabrication issues, so the choice of glue-lam timber system with sandwichpanels appears the best compromise. In the second part, the hygrothermal performance and dynamic thermal characteristics of building components and junction details was simulated and verified for three main Italian climatic zones, based on: UNI 6946:2008, UNI 13788:2003, UNI EN ISO 13786:2008 standards