1,720,993 research outputs found
An experimental investigation on the indoor hygrothermal environment of a reinforced-EPS based temporary housing solution
Full text linkIn a post-disaster scenario, temporary lightweight housing solutions are generally used for quickly providing disaster victims with a temporary living place. Developed for limited periods of occupation and typically built shortly with lightweight technologies, people can end up living in these buildings, especially in low-income countries, for years or even decades. Considering a possible long-occupation period, it is necessary to improve the ability of these building to grant adequate comfort even considering their temporary character. Nevertheless, few studies in the literature are focused on the indoor thermal comfort environment of these buildings. This paper shows some results of a study addressed to analyze and improve the indoor hygrothermal behavior of a novel, modular and lightweight temporary housing solution, named HOMEDONE, based on the assembly of 3D-reinforced EPS panels. After a preliminary characterization of the system in terms of in situ thermal transmittance and airtightness performance, useful to provide a reference for the numerical simulations, the indoor hygrothermal behavior of an experimental unit is monitored during the spring and the summer season. Then, hygrothermal simulations are carried out to verify the occurrence of the experimentally observed moisture-related issues in different climatic contexts and to evaluate the effectiveness of possible improvement solutions. The results showed a low in situ thermal transmittance and good airtightness performance of the HOMEDONE construction system. However, the experimental measurements revealed that, at closed opening condition, indoor air temperature and relative humidity can be very high and unacceptable during the cooling season, due to the low thermal storage capacity and the low moisture buffering/water absorption capacity of the building components. The simulations demonstrate that an internal finishing layer with adequate moisture buffering capacity can significantly reduce RH levels, preventing condensation issues and mold growth. Nevertheless, the use of the HOMEDONE unit for long periods of occupation is discouraged, especially in hot climates, unless appropriate measures to reduce the indoor overheating and to improve thermal comfort are adopted
Thermal performance of a novel lightweight emergency construction system in different climates
No full textPrefabricated, lightweight construction systems, thanks to their quicker construction processes, cheapness, higher portability, and adaptability, are increasingly proposed all around the world as emergency architectures (after natural disasters, pandemics, etc.), and as affordable housing solutions in countries with increasing housing demand. Due to their low thermal inertia, however, these buildings are often characterized by poor thermal performance in hot climates due to indoor overheating. The possible application of passive cooling measures is often investigated to improve their thermal performance. Among others, cool materials present some advantages in terms of ease of application and costs. However, few studies investigated the impact of this passive strategy on the thermal performance of emergency buildings. For this reason, this work evaluates the impact of cooling materials on the thermal performance of a novel lightweight prefabricated construction system (HOMEDONE) based on the assembly of reinforced-EPS panels. First, a numerical model of an experimental mock-up was created and calibrated on experimental data. Then, the thermal performance of a typical temporary housing solution was numerically evaluated under different climatic locations. Finally, the effectiveness of cooling finishing materials is investigated. The potential of cooling materials in reducing the energy demand for the studied construction system is then highlighted
Improving the livability of lightweight emergency architectures: A numerical investigation on a novel reinforced-EPS based construction system
No full textIn the aftermath of catastrophic events, lightweight construction systems are often used to build temporary emergency architectures. However, if suitable environmental control systems are not present, as may occur in post-disaster scenarios, these buildings provide poor indoor thermal conditions, especially in hot climates, which may jeopardize the occupants’ physical and mental health in case of longer periods of occupations. In these contexts, passive cooling techniques are the preferred strategies to improve the indoor thermal environment. However, only a few papers evaluated the effectiveness of these measures on emergency buildings, also considering calibrated simulations, different climates, costs, and operational feasibility. In this work, the thermal performance of a novel emergency construction system, still not sufficiently studied in the literature and based on the assembly of 3D-reinforced EPS panels, is examined. First, a numerical model of an experimental unit is calibrated on experimental data. Then, the thermal performance in hot and temperate climates of a reference building, recently adopted in emergency scenarios, is numerically evaluated and improved through passive cooling measures, i.e. shading, thermal buffering, natural ventilation, and cooling materials. Results show high summer thermal discomfort in all climates. The efficacy of the different measures depends on climatic contexts, with natural ventilation, combined with cool roof materials or blinds (for temperate and hot climates, respectively), providing the best trade-off between thermal comfort, costs, and feasibility. However, the summer indoor thermal discomfort cannot be completely reduced. This study helps decision-makers and people to correctly improve the living conditions and sustainability of emergency architectures
Analisi sperimentale e numerica per la valutazione e il miglioramento delle prestazioni energetiche di un sistema costruttivo emergenziale in EPS-rinforzato
No full textNegli ultimi decenni, stiamo assistendo ad un costante aumento di emergenze umanitarie causate da conflitti, disastri naturali e pandemie. Tali eventi hanno evidenziato la necessità di sviluppare sistemi costruttivi in grado di consentire la costruzione di alloggi temporanei e ospedali da campo in poco tempo. Tuttavia, progettati principalmente per brevi periodi di occupazione (due o tre anni), tali sistemi risultano spesso carenti in termini di durabilità, qualità ambientale interna e prestazioni energetiche. Nonostante ciò, non è raro che le persone finiscano per vivere in questi edifici per periodi prolungati, addirittura decenni. Pertanto, risulta sempre più evidente la necessità di promuovere lo sviluppo di tecnologie costruttive che, pur mantenendo le caratteristiche essenziali per rispondere all’esigenze emergenziali (rapidità di costruzione e trasportabilità), siano in grado di garantire un adeguato standard abitativo agli occupanti, consentendo il graduale superamento del concetto di temporaneità verso un’edilizia eco-solidale di maggiore qualità. Questo studio riporta alcune evidenze di un’ampia campagna sperimentale e numerica volte ad indagare e migliorare il comportamento termo-energetico di un sistema costruttivo leggero e innovativo, chiamato “Home Done”, appositamente sviluppato per interpretare ad un livello qualitativo più elevato la
crescente domanda di edifici emergenziali e a basso costo. Le attività presentate si suddividono in sperimentali, volte a verificare eventuali problematiche di comfort interno data la natura leggera del sistema, e numeriche, volte, da un lato, a valutare le prestazioni energetiche in diversi contesti climatici e, dall’altro, a proporre strategie migliorative. Le misurazioni effettuate hanno rilevato problematiche di surriscaldamento degli ambienti, rendendo necessarie strategie di raffrescamento passivo nei climi caldi, data la necessità di contenere le installazioni impiantistiche ed i relativi consumi per tali tipologie di edifici. Le analisi numeriche hanno mostrato ottimi risultati sul piano dei consumi energetici, con possibilità di ottenere riduzioni importanti dei consumi energetici nei climi caldi mediante l’introduzione di uno strato interno termicamente inerziale
Proprietà termiche delle murature
No full textThe recently revised European standard EN 1745 describes methods for the determination of the thermal conductivity of solid masonry units, mortars, masonry units with formed voids and “composite” masonry units, i.e. masonry unit incorporating additional material in the voids, such as thermal insulation. The determination of the “dry” and “design” thermal conductivity values can be defined based on tabulated data, measurements, calculations or a combination of these. The main novelty of the new version lies in the inclusion of a method for the determination of the thermal design values of composite masonry elements. More details in this article
Impact of Climate and Economic Scenarios on the Global Costs of Nearly Zero Energy Buildings Renovations. A Stochastic LCC on a Reference Multi-story Building
No full textNational long-term building renovation strategies should reduce the actual financial gap between nearly Zero Energy (nZE) and “minimum energy requirement” levels, to enlarge the impact of buildings’ energy saving on climate neutrality. However, the design of specific policies to bridge this gap strongly depends on the long-term expected value and volatility of the macroeconomic environment during the building's lifetime. Standardized Life Cycle Costing methods disregard the long-term uncertainty affecting the macroeconomic variables and consequently misrepresent the associated risk on the economic convenience of building renovation. The present work applies a “stochastic” approach to LCC on alternative renovation options of a reference building located in different Italian climate areas towards the nZE target. The analysis focuses on the analysis of the impact of alternative macroeconomic scenarios on the investment gap between the “cost-optimal” and the nZE solutions. A widespread application of this methodology in the context of the European “Cost-Optimal” framework would allow establishing specific funding schemes and financing instruments to push a real “renovation wave” of EU buildings
Il BIM nelle simulazioni energetiche di edifici: interoperabilità nel processo BIM-to-BEM
No full textL’articolo evidenzia le potenzialità, i limiti e le problematiche dei processi
di trasformazione “BIM-to-BEM”, ovvero da modelli BIM a modelli per l’analisi
della prestazione energetica degli edific
Impact of Occupants’ Behavior Uncertainty on Building Energy Consumption Through the Karhunen-Loève Expansion Technique: A Case Study in Italy
No full textIn Europe, the building sector is liable for 40% of the entire energy consumption (EC) and 35% of the total greenhouse emission. Building energy performance simulation (BEPS) tools are fundamental to assess the EC of both new buildings and energy retrofit intervention, and to verify the reaching of the requirements set by the national building energy standards. However, the results obtained from these tools are often unreliable due to the different assumptions that must be made in case of data input uncertainty, generating a “performance gap” between observed and predicted EC. Occupants’ behavior (OB) is one of the most difficult parameters to be estimated since affected by high uncertainty that may strongly affect the numerical results. However, the most recent BEPS tools neglect the existing uncertainty by modeling the occupant behavior through deterministic hourly-defined profiles. For this reason, in this work, the impact of OB uncertainties on EC is evaluated by applying a Karhunen-Loève Expansion (KLE) on deterministic hourly defined profiles. A typical Italian residential building is modeled and calibrated on EC data. Then, occupancy behavior-related profiles, such as heating setpoint, internal thermal loads, and windows opening, are randomly perturbed using the KLE technique. The results demonstrate that the heating setpoint patterns uncertainty has the highest impact on EC. Moreover, the more the energy performance of the building, the higher the impact of heat gains and losses caused by OB
Seismic solution based on the use of cross-laminated timber (clt) panels with sliding joints as infilled earthquake bracing system for rc framed architectures
Full text linkCross Laminated Timber (CLT) has gaining more and more attention in the research and professional field as a sustainable and promising construction system for mid- and high-rise structures. The need of buildings higher than that usually built with CLT has pushed the research towards the development of innovative hybrid techniques in which steel framed structures incorporate CLT shear walls. This concept may be potentially extended to existing RC framed buildings where infilled CLT shear walls may constitute the base for an integrated seismic and energy retrofit solution. In order to investigate this potentiality, this paper present a preliminary experimental study focused on the diagonal strut behaviour of CLT panels. In particular, diagonal compression tests on 3-ply panels have been carried out also by simulating the confinement effect provided by the structural frame. A comparison with the results of similar tests on CLT panels with different number of layers and thickness has been also provided. The results of this research have demonstrated that CLT panels has a higher strength and stiffness if confined. Then, the confinement effect provided by the RC frame on the infill should be accurately considered in the strengthening design
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