1,721,163 research outputs found
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
An experimental investigation on the indoor hygrothermal environment of a reinforced-EPS based temporary housing solution
Get PDFIn 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
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
Ricostruzione di spettri di assorbimento da misure di assorbimento globale – Un problema inverso
No full textManti permeabili per tetti traspiranti
No full textThat the ventilation in the roof effectively fulfils the cooling function of a building is a well-established concept.
However the common opinion associates the working of a
ventilated roof only related to the “chimney effect”, neglecting the
fact that in discontinuous coverings (such as clay tiles coverings),
most of the heat is dispersed by ventilation through the joints of
the tiles, with beneficial effects. This paper reports the results of
several experimental activities in this regard.
We monitored the summer thermal performance of full-scale roofs,
built according to the current requirements of thermal transmittance, with different types of coverings (clay tiles, copper) and
height of air gap (3 cm and 6 cm). Results show that clay tiles
roofs are more effective than copper roofs in cooling the internal
environment, and that in roofs with low thermal transmittance, it
is of little convenience to invest in elevated air gaps.
A tracking smoke test of the air movement into the roofs showed
that most of the air entering into the gaps of clay tiles roofs then
escapes through the joints of the tiles.
Laboratory tests allowed to quantify this airflow and to correlate
it to the amount of heat removed by ventilation in a clay tile roo
Ridurre la sopravvalutazione dei rischi associati a investimenti per l’efficientamento energetico
No full textAn ERp57-mediated disulphide exchange promotes the interaction between Burkholderia cenocepacia and epithelial respiratory cells
Get PDFPrevious studies have demonstrated that extracellular glutathione reduces the ability of the Cystic Fibrosis pathogen Burkholderia cenocepacia to infect primary or immortalized epithelial respiratory cells. We report here that the adhesion and invasion ability of B. cenocepacia is limited also by thiol-oxidizing and disulphide-reducing agents and by protein disulfide isomerase (PDI) inhibitors. PDI inhibitors also reduce the proinflammatory response elicited by cells in response to Burkholderia. These findings indicate that a membrane-associated PDI catalyzes thiol/disulphide exchange reactions which favor bacterial infection. The combined use of selective PDI inhibitors, RNA silencing and specific antibodies identified ERp57 as a major PDI involved in the interaction between B. cenocepacia and epithelial cells. This study contributes to the elucidation of the Burkholderia pathogenic mechanisms by showing that this microorganism exploits a membrane-associated host protein to infect epithelial cells and identifies ERp57 as a putative pharmacological target for the treatment of Burkholderia lung infections
Sustainable and resilient strategies for touristic cities against COVID-19: An agent-based approach
No full textTouristic cities will suffer from COVID-19 emergency because of its economic impact on their communities. The first emergency phases involved a wide closure of such areas to support “social distancing” measures (i.e. travels limitation; lockdown of (over)crowd-prone activities). In the “second phase”, individual's risk-mitigation strategies (facial masks) could be properly linked to “social distancing” to ensure re-opening touristic cities to visitors. Simulation tools could support the effectiveness evaluation of risk-mitigation measures to look for an economic and social optimum for activities restarting. This work modifies an existing Agent-Based Model to estimate the virus spreading in touristic areas, including tourists and residents’ behaviours, movement and virus effects on them according to a probabilistic approach. Consolidated proximity-based and exposure-time-based contagion spreading rules are included according to international health organizations and previous calibration through experimental data. Effects of tourists’ capacity (as “social distancing”-based measure) and other strategies (i.e. facial mask implementation) are evaluated depending on virus-related conditions (i.e. initial infector percentages). An idealized scenario representing a significant case study has been analysed to demonstrate the tool capabilities and compare the effectiveness of those solutions. Results show that “social distancing” seems to be more effective at the highest infectors’ rates, although represents an extreme measure with important economic effects. This measure loses its full effectiveness (on the community) as the infectors’ rate decreases and individuals’ protection measures become predominant (facial masks). The model could be integrated to consider other recurring issues on tourist-related fruition and schedule of urban spaces and facilities (e.g. cultural/leisure buildings)
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
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