The laboratory of Fisica Tecnica has a long lasting tradition of research activities developed in the fields of applied acoustics, indoor environment characterization, and thermo-hygrometric properties of materials. More recently the activities in these different fields converged on specific topics that, although often studied independently, all contribute to the research in the field of sustainable, energy-efficient, and comfortable building design. The paper outlines the researches of the group in this field: thermo-hygrometric and acoustic characterization of sustainable materials; study of PCM solutions for energy storage; use of numerical models to simulate fire dynamic, heat transfer, and acoustic problems; analysis of the interactions between technical services and buildings and their effect on energy efficiency and comfort; renewable energy; analysis of thermal, acoustic and visual comfort conditions in indoor environments, and their relation with energy optimization needs.

Il presente lavoro riguarda lo studio di un materiale composito innovativo, gesso scagliola miscelato a perline di elastomero da pneumatici fuori uso (PFU), nel duplice intento di tutelare la salute dell’uomo, il territorio e contenere il consumo energetico. In particolare, sono state valutate le proprietà meccaniche, termiche ed acustiche di malte realizzate con tali materiali. Negli impasti sono state aggiunte al gesso sfere di elastomero in varie percentuali e con frazione granulometrica pari a 0,8-1,6 mm e 1,6-2,5 mm, da cui si sono ricavati i conglomerati più idonei per impieghi non strutturali.

Le malte di calce sono tra i materiali più rispettosi dei principi che regolano la bioedilizia. Pertanto, in questo lavoro, sono state studiate le proprietà di malte di calce addizionate di aggregati non tradizionali in sostituzione parziale della sabbia calcarea. I risultati ottenuti da prove reologiche, meccaniche e fisiche sono estremamente interessanti per alcune tipologie di conglomerato.

La sperimentazione oggetto del presente lavoro riguarda lo studio di un materiale composito costituito da gesso scagliola inglobante fibre naturali di paglia. Tale sperimentazione è orientata nella direzione della progettazione di edifici il più possibile ecosostenibili. Si sono valutate le proprietà fisiche, meccaniche e prestazionali di tale conglomerato al variare delle percentuali in peso dell’aggregato (0,5-2%) rispetto al gesso, da cui si sono ricavati gli impasti più idonei per applicazioni non strutturali di alleggerimento, di isolamento termico e fono-assorbimento

The ZERO Project is aimed to demonstrate that the use of energy variable is a useful tool to redefine the structure of both the individual building and its installations and the organization of a whole neighborhood where each element (buildings, equipment, infrastructure) are in a position to communicate with each other using the technology provided by the ICT sector. The activities aim to provide fast-prototyping, instrumentation, methodologies and equipment for material characterization of new components in the field of energy efficiency, microgeneration, renewables and, in general, of energy production systems dimensioned on the end user needs (energy hubs, district heating/cooling, etc.).

The present work, developed within the research project HPWalls (High Performance Wall Systems), aims to perform an experimental research on lightweight cementitious mortars containing recycled aggregates from the production process of the EPS (Expanded Polystyrene). The recycling of an industrial waste and its transforming in a new second raw material can be considered as an important strategy to reduce industrial waste flows and minimize the consumption of new resources and energy. Furthermore, the widespread use of plastics in the building field, in particular EPS, requires new approaches for the improvement of their environmental impact, in terms of productive process- with the optimization of the industrial process and the minimization of the sub-products- as well as in terms of life end strategies. That waste can represent an efficient tool for local enterprises and technical experts dealing with characterization and mix design applied to recycling materials. As a consequence, the project aims to assess the characteristics of that waste (light weight, low thermal conductivity, low density, high availability) in order to define a new competitive building material characterized by high technical performances and low impact manufacturing process. The mixtures, prepared starting from the percentages of raw materials defined according to the norms for standardized mortar, have taken into account the partial/total substitution of fine aggregate (sand) with recycled EPS with different grain size distributions. The specimens were analyzed starting from the workability of the raw blends and the mechanical strengths; the thermal properties (thermal conductivity, thermal diffusivity) were measured while hygric and acoustic properties measurements are currently under development.

The thermal performance of hollow bricks, as elements of the building envelope, is mainly linked to the presence of air cavities. The heat propagates within those components through the three basic modes of transmission: conduction in the solid matrix, convection of the air cavity, direct radiation between surfaces that face in the cavities. The rigorous treatment of such heat exchange is very complex even in thermal conditions close to the environment with moderate temperature differences. In engineering practice a simplified calculation method is used, as incorporated in national and international standards, which reduce heat transfer into the cavity to an equivalent heat conduction that results in the transport of the same thermal power. UNI EN ISO 6946 and UNI 10355 follow this method by proposing a simplified model of computation that lead to different results. Given the importance that the correct assessment of the insulation performance of the envelop in the context of energy certification of buildings it was considered useful to undertake a detailed analysis of the reliability of the estimation methods of heat transfer in air cavities of hollow bricks. The study was conducted with the use of different tools, numerical and experimental. An experimental study was conducted in the laboratory with heat transmission measurements, in specimens with parallelepiped cavities, through the guarded hot plate apparatus according to UNI EN 12664. The analysis of the results, numerical and experimental, compared with the predictions obtained from simplified models of technical standards, have called attention to the order of magnitude of the calculation accuracy obtainable with such procedures. For certain geometric configurations and boundary conditions, the application of the standard procedures can lead to large errors of evaluation of the thermal resistance of the cavity.

Given the importance of the assessment of the insulation performance of the building envelope in the context of energy certification of buildings, a detailed analysis of the reliability of the methods of evaluation of heat transfer in the air cavities of hollow blocks has been carried out. An experimental study was conducted in the laboratory. Heat transfer measurements on specimens with parallelepiped cavities were done, through a guarded hot plate device according to UNI EN 12664. A numerical analysis of the heat transfer in the specimens through the software ANSYS FLUENT was carried out. The analysis of the numerical and experimental results when compared with the predictions obtained from simplified models of technical standards, have called attention to the order of magnitude of the calculation accuracy obtainable with such procedures. For some geometric configurations and boundary conditions, the application of the standards can lead to large errors of evaluation of the thermal resistance of the cavity.

The present work, developed within the research project HPWalls (High Performance Wall Systems), aims to perform an experimental research on lightweight cementitious mortars containing recycled aggregates from the production process of the EPS (Expanded Polystyrene). The recycling of an industrial waste and its transforming in a new second raw material can be considered as an important strategy to reduce industrial waste flows and minimize the consumption of new resources and energy. Furthermore, the widespread use of plastics in the building field, in particular EPS, requires new approaches for the improvement of their environmental impact, in terms of productive process- with the optimization of the industrial process and the minimization of the sub-products- as well as in terms of life end strategies. That waste can represent an efficient tool for local enterprises and technical experts dealing with characterization and mix design applied to recycling materials. As a consequence, the project aims to assess the characteristics of that waste (light weight, low thermal conductivity, low density, high availability) in order to define a new competitive building material characterized by high technical performances and low impact manufacturing process. The mixtures, prepared starting from the percentages of raw materials defined according to the norms for standardized mortar, have taken into account the partial/total substitution of fine aggregate (sand) with recycled EPS with different grain size distributions. The specimens were analyzed starting from the workability of the raw blends and the mechanical strengths; the thermal properties (thermal conductivity, thermal diffusivity) were measured while hygric and acoustic properties measurements are currently under development

Attualmente, il settore delle costruzioni ha assunto un ruolo chiave nella lotta ai cambiamenti climatici e nella riduzione delle emissioni di CO2 in atmosfera. L'obsolescenza del patrimonio edilizio esistente ha reso più che mai indispensabili gli interventi di recupero edilizio, necessari a raggiungere livelli ottimali di efficienza energetica e di sostenibilità. In tale ottica si inserisce la proposta di un sistema integrato innovativo, denominato "Kit albero solare", che, ispirandosi al concetto della pergola, funge da sistema di captazione solare, conciliando aspetti di qualità architettonica ed ecocompatibilità. Esso è costituito da esili strutture in acciaio modulari e ripetibili che avvolgono l'edificio come una "pelle", dotandolo di dispositivi solari integrati e buffer spaces abitabili, quali serre, portici e logge, e assicurando l’ombreggiamento, la ventilazione naturale e il recupero delle acque piovane. Si incrementa così la superficie di captazione attiva dell'energia solare, altrimenti estremamente limitata negli edifici esistenti, senza la necessità di effettuare interventi invasivi. Le simulazioni in regime dinamico evidenziano come il Kit Albero Solare incida notevolmente sulla riduzione del fabbisogno energetico dei fabbricati, trasformandoli da consumatori a produttori di energia. Inoltre, poiché la nuova Direttiva Europea 2012/27/UE punta ad aumentare il tasso di ristrutturazione degli immobili, ponendo nuovi obblighi soprattutto a carico del patrimonio edilizio di proprietà pubblica, la proposta trova un ideale ambito di applicazione nei contesti periferici di edilizia residenziale pubblica e risulta, pertanto, di forte interesse per la sua innovatività e per la rispondenza alle politiche ambientali nazionali e internazionali.

La gestione del conflitto tra istanze ambientali ed energetiche. Pianificazione territoriale e declinazioni progettuali nell’uso di impianti fotovoltaici. Le giuste sinergie ed i giusti rapporti tra governo del territorio e corretto inserimento delle fonti rinnovabili in un contesto energetico in cambiamento, il cui fine ultimo è quello di perseguire il principio della sostenibilità per promuovere emissioni low-carbon.

Si riportano i risultati di una campagna di misure su intonaci di terra cruda mista a paglia d’orzo in differenti percentuali. I valori dei parametri termoigrometrici ottenuti portano a ritenere tale materiale più idoneo, rispetto ad altri materiali da intonaco, a mitigare le condizioni termoigrometriche degli ambienti confinati. A tale fine è stato utilizzato il software WUFI+ per una analisi dettagliata delle condizioni termoigrometriche in un monolocale campione realizzato con pareti laterali e soffitto rivestiti con intonaco di terra cruda-paglia. La prestazione termoigrometrica è stata confrontata con quella dello stesso locale in presenza di intonaco di gesso. Il confronto tra le due soluzioni è stato condotto nelle due situazioni di: a) edificio passivo, in assenza di impianto di climatizzazione; b) edificio con impianto di condizionamento in grado di mantenere condizioni interne di temperatura ed umidità controllate tutto l’anno. L’analisi dei risultati della simulazione ha portato alla conclusione che l’adozione dell’intonaco in terra cruda alleggerita con il 4% di paglia realizza condizioni igrometriche interne migliori con un più intenso scambio di flusso di vapore d’acqua tra le superfici interne e l’aria interna. Inoltre, in presenza dell’impianto di condizionamento, il consumo energetico per la umidificazione-deumidificazione dell’aria ambiente è più ridotto per la soluzione di intonaco in terra-paglia.

Nell'articolo si dimostra che l’involucro opaco svolge un ruolo importante nella determinazione della prestazione termoenergetica complessiva dell’edificio, ma resta comunque solo uno dei fattori influenti. Soprattutto in regime termico dinamico l’interazione tra le varie componenti di involucro, il clima esterno, gli apporti interni e l’impianto, può essere tale da rendere imprevedibile la prestazione reale in opera.

Three different basic mixtures were prepared, by mechanical compaction, with different types of clays: quarry fine, kaolinite, and bentonite. Two groups of mixtures were studied, the first group without lime and the second with the addition of 5% hydrated lime. A comparison between the measured hygrothermal performances of the mixtures and their micro structural composition was performed. Micro structural morphology and chemical composition was characterized using SEM with EDS, mineralogy using XRD, and porosity using gravimetrics/He pycnometry and N2 physisorption with BET and BJH analysis. Hygrothermal functional properties were characterised as moisture-dependant thermal conductivity, moisture-dependent heat capacity, vapour sorption isotherms, and water vapour permeability.

An experimental research is ongoing in the “Laboratorio di Termofisica dei Materiali” of Politecnico di Bari on sustainable building materials achieved by a basic mix of clay, silt, sand with local additives (i.e. lime) and natural components originating from agricultural waste produced in Mediterranean area (i.e. straw, olive trees waste, etc.). The agro-waste disposal represents one of the main issue at national and international level. The research aims to develop a sustainable material suitable for building applications (i.e panels, bricks, mortar) with high physical and hygrothermal performances.

Experimental research carried out on two types of buildings that are the examples of vernacular architecture in Southern Italy, namely the Sassi of Matera and the Trulli of Alberobello are outlined in this paper. Experimental measurements on thermal properties, energy performance and hygrothermal indoor comfort were carried out to validate the numerical code provided by DesignBuilder/EnergyPlus that was used to investigate the buildings on a yearly basis. The very high thermal mass of the building structures give rise to a quasi-constant seasonal indoor temperature with no need for air conditioning in the mid- and peak-summer seasons. The seasonal thermal storage can almost guarantee near the comfort levels using simple heating systems during the cold season.