238 research outputs found
SHALLOW GEOTHERMAL SYSTEMS SUSTAINABILITY THROUGH A HOLISTIC APPROACH: THE CANTON TICINO TEST SITE (CH)
No full textDecenni di estrazione ed utilizzo di combustibili fossili hanno prodotto forti emissioni di gas clima-alteranti e una completa dipendenza da fonti non rinnovabili, con conseguenze politiche e socio-economiche. La transizione energetica che stiamo affrontando si affida alle energie rinnovabili, producendo un forte impatto sulla riduzione delle emissioni di CO2. Tra i diversi tipi di energie rinnovabili attualmente disponibili, l'energia geotermica superficiale rappresenta una delle migliori soluzioni per il condizionamento degli edifici grazie alla sua disponibilità e alla grande efficienza termica. Tali grandi vantaggi hanno portato ad un netto aumento delle installazioni in spazi progressivamente limitati, sollevando problemi di gestione relativi prevalentemente alla sostenibilità termica nel lungo periodo e ai potenziali conflitti tra utenti delle acque sotterranee. Nel presente lavoro, la gestione dei sistemi geotermici superficiali (SGS) è valutata a diverse scale spaziali partendo da un caso pilota in Svizzera. La prima parte del lavoro si è concentrata sulla realizzazione di mappe del potenziale tecno-economico, utili per una stima preventiva della fattibilità di un nuovo impianto a circuito chiuso. Il confronto tra queste mappe e l'attuale approccio gestionale derivante dalla normativa sulla protezione delle acque sotterranee ha mostrato che i settori nei quali nuovi sistemi sono consentiti sono spesso le aree dove si osserva un potenziale geotermico inferiore. La seconda parte del lavoro si è concentrata sull'analisi di un caso studio regionale utilizzando una procedura di caratterizzazione idrogeologica, monitoraggio e modellistica delle acque sotterranee. I risultati hanno dimostrato che la comprensione del reale stato termo-idrogeologico di un acquifero è la base fondamentale per eseguire un’analisi locale di sostenibilità termica per SGS, soprattutto nelle aree ad alta densità. La terza parte del lavoro ha proposto un modello numerico olistico idro/termogeologico per simulare l'attuale stato termico del sottosuolo di un'area urbanizzata e le potenziali interazioni tra SGS autorizzati, andando oltre agli attuali schemi di gestione che considerano ogni impianto come separato a fini di valutazione di sostenibilità idraulica/termica. I risultati hanno mostrato che l'elevata quantità di SGS installati in spazi limitati sta progressivamente creando reciproche interferenze idrauliche e termiche: negative, con una riduzione dell'efficienza e della sostenibilità o (raramente) positive quando si instaura un effetto sinergico accidentale dovuto a posizioni e profili di utilizzo favorevoli (pertanto non gestito). La restituzione attraverso la zona insatura del terreno potrebbe essere un valido metodo per ripristinare l’acquifero senza alterare in modo rilevante la temperatura dell’acqua sotterranea, garantendo così la sostenibilità a lungo termine di SGS in zone urbane. L'approccio multi-scala proposto consente di migliorare la gestione a diversi livelli. Nei prossimi anni il condizionamento degli edifici si baserà sempre più su SGS per garantire la domanda di energia termica, con un conseguente aumento del numero di richieste di autorizzazione in spazi limitati. Saranno quindi sempre più richiesti studi olistici multi-scala, come quello proposto, per fornire l'informazione tecnico/scientifica necessaria per una migliore gestione, valutando la sostenibilità termica a lungo termine dello sfruttamento di energia geotermica superficiale, soprattutto in aree urbane
Techno-economic mapping for the improvement of shallow geothermal management in southern Switzerland
No full textCantone Ticino, a mountainous region located in the southern part of Switzerland, is greatly affected by the continuous growth of subsurface exploitation through the use of both closed-loop and open-loop geothermal systems. In this study, techno-economic maps for shallow geothermal potential of Cantone Ticino are produced, considering closed-loop systems. The work starts with the identification of the main parameters affecting the techno-economic potential such as GST and thermal conductivity. Maps for different indicators of techno-economic feasibility are created and compared against real data/measurements. An empirical method is tailored to derive a map of the techno-economic geothermal potential, expressed as meters required to provide 1 kW of installed power. The produced map shows an overall discrepancy from real installed length data of approximately ±23%. Moreover, compared with current regulation, the produced maps show an unoptimized management of the shallow geothermal resource, since high potential zones are commonly located where the installation of BHE is not permitted and often closed-loop systems are installed where the estimated potential is lower, mainly in alluvial fans. In light of these considerations, the authorization process in Cantone Ticino for BHE should be revised taking into account the real techno-economic potential
Intensive thermal exploitation from closed and open shallow geothermal systems at urban scale: unmanaged conflicts and potential synergies
No full textThe use of shallow geothermal systems (SGS) as a proficient technology to provide clean thermal energy has become increasingly widespread throughout the world, especially in urban environments, with a significant increase in systems density. At European level, the current authorization schemes for new SGS rarely consider the current thermal state of the subsurface and the potential presence of neighbouring systems. The paper presents a pilot urban case study, showing high SGS deployment, analysed through a holistic city-scale 3D numerical model simulating mutual interactions between open and closed-loop systems. Results show that the high amount of installed SGS in limited space is progressively creating mutual hydraulic and thermal interferences: negative, with a reduction of SGS efficiency and sustainability or (rarely) positive, when an accidental and unmanaged synergic effect is established due to favourable exploitation patterns and SGS locations. Numerical modeling further highlighted that the restitution through the vadose zone could be a valid method to hydraulically reinstate the aquifer without significantly altering groundwater undisturbed temperature even at shallow groundwater depth. Results show that neglecting an underground holistic vision of the hydro/thermogeological processes in urban areas could result in long-term severe efficiency losses and environmental issues for SGS solutions, also given the increasing use of shallow geothermal energy in the building air conditioning sector
Convenience in Funding Upgrading Works
No full textWith reference to upgrading actions on existing building stock, Construction Procurement Guidance, No.7 Whole Life Costs (Office of Government Commerce) states: ‘All procurement must be made solely on the basis of value for money in terms of the optimum combination of global costs and quality to meet the user’s requirements’. Cash-flow analyses allow showing the economic value of investments for alternative technological upgrading works extended all along their service lives. Optimisation of choices is not only a matter of cash-flow analyses—choices should not be made only according to the lowest costs but also considering several aspects that can be brought back to the concept of ‘technical-sustainable value’, which mainly derives from competent functional and environmental assessments of the reference analysis system. The mentioned interrelation should theoretically be adequately considered but this is seldom the case in the common building practice. Cost estimate for an engineered system has to entail much more detailed analyses on costs, energy, sustainability and technologies. Possible technological solutions would be convenient in terms of technological/technical utility, but less convenient in monetary terms for the funding subject. Under the economic point of view, cash outflow means less economic convenience in funding a given technology. All that stated above, nowadays effective data-display global cost-quality indicators are rarely available in literature. The present manuscript introduces to the reader fundamentals of an economic tool proposal designed by the author with the use of synthetically displaying interrelations between cash-flow scenarios and quality-sustainability in upgrading processes on existing buildings. Fundamentals have been tested on a reference case study. Then, fundamentals have been contextualized to the Italian Legislative framework: in Italy, in multi-owner existing residential buildings, expenditure allocation is carried out based on thousandths. The thousandth type to be considered is due to the configuration of the case under review and to balance-sheet expenditure to be allocated to owners. Property thousandths allocated to housing units have been used to allocate expenses for technological/energy upgrading works. The author has tried to find out the amount of a possible bank investment that a user might start at building Time ‘0’ to theoretically clear possible economic losses, trying to highlight technical utility of the technological solution that would be disadvantaged in economic terms. ‘Neutral’ mathematical finance formulas have been used to calculate the theoretical capital to be invested by an owner based on the reference cash-flow scenario. Conclusion will be drawn at the end of the manuscript
Recupero edilizio e nuova costruzione. Non solo risparmio energetico. Importanza della valutazione della fattibilità applicativa a monte della modellazione energetica
No full textThe expressions ‘low environmental impact’ and ‘energy efficiency’ mean much more than ‘compliance to regulation and technical specifications’ (89/106/ EEC, article 4).
Nowadays, solutions implemented in actions on buildings at least have to comply with regulatory values or parameters with reference to a specific time outlook. This is due to policies and guidelines issued at several levels, starting from the European one to get to the local one, promoting: for new buildings, reviews of design processes so as to create sustainable buildings providing for high-quality housing, for existing buildings, reviews on as-built assets so as to limit energy consumption.
Designers selecting potentially applicable ‘sustainable’ technologies should not only assess their profiles in terms of energy and performance which, of course, are essential.
Together with the abovementioned issues, in addition to convenience, critical points and viability constraints should be reasonably taken into account during the selection process.
For this purpose, some ideas are introduced in form of a journalistic discourse, which, according to the author, can be useful to those designers who have to select from different ranges of viable technological solutions, both based on traditional building practices and on new or emerging practices
Synthesis through electrospinning of La1-xSrxCo1-yFeyO3 ceramic fibers for IT-SOFC electrodes
No full textMicroencapsulation of phenolic compounds from olive pomace using spray drying: A study of operative parameters
No full textRevision of hydrothermal constraints for the installation of closed-loop shallow geothermal systems through underground investigation, monitoring and modeling
No full textThe hydrothermal area of Ponte Arche (Italian Alps) hosts favorable geothermal conditions and presence of thermal water, which is used for therapeutic purposes. Political constraints are in force, since the district is classified as “potentially subject to geothermal manifestations”. The Government of the Province of Trento exceptionally approved a pilot shallow geothermal closed-loop system: underground investigations and high spatial-temporal resolution monitoring were performed in order to assess the absence of thermal interference between the installed borefield and the neighboring hydrothermal wells. Acquired thermo-geological and energetic information were conveyed into a numerical model devoted to predict the long-term thermal behavior of the system, detecting the potential arise of thermal interference towards hydrothermal wells. Before the long-term analysis (50 years), the numerical model was doubly validated against both short-term and medium-term response. The simulation of the long-term real-case scenario shows that the thermal plume developed by the system is limited to a diameter of 74 m, while for a long-term heating-only scenario it is limited to a maximum diameter of 96 m. Long-term results for both real and heating-only scenario show that under no circumstances the experimental closed-loop system would interfere with the neighboring hydrothermal wells distant 610, 1350 and 1450 m
Mitogenomes from Two Uncommon Haplogroups Mark Late Glacial/Postglacial Expansions from the Near East and Neolithic Dispersals within Europe
No full textThe current human mitochondrial (mtDNA) phylogeny does not equally represent all human populations but is biased in favour of representatives originally from north and central Europe. This especially affects the phylogeny of some uncommon West Eurasian haplogroups, including I and W, whose southern European and Near Eastern components are very poorly represented, suggesting that extensive hidden phylogenetic substructure remains to be uncovered. This study expanded and re-analysed the available datasets of I and W complete mtDNA genomes, reaching a comprehensive 419 mitogenomes, and searched for precise correlations between the ages and geographical distributions of their numerous newly identified subclades with events of human dispersal which contributed to the genetic formation of modern Europeans. Our results showed that haplogroups I (within N1a1b) and W originated in the Near East during the Last Glacial Maximum or pre-warming period (the period of gradual warming between the end of the LGM, ~19 ky ago, and the beginning of the first main warming phase, ~15 ky ago) and, like the much more common haplogroups J and T, may have been involved in Late Glacial expansions starting from the Near East. Thus our data contribute to a better definition of the Late and postglacial re-peopling of Europe, providing further evidence for the scenario that major population expansions started after the Last Glacial Maximum but before Neolithic times, but also evidencing traces of diffusion events in several I and W subclades dating to the European Neolithic and restricted to Europe
Parameter Optimization for the Electrospinning of La1-xSrxCo1-yFeyO3-δ Fibers for IT-SOFC Electrodes
No full textLa1-xSrxCo1-yFeyO3-δ (LSCF) fibers are synthesized through the the single-needle electrospinning method. The formation of nanofibers is a function of the operating parameters, i.e., rotational speed of the support, solution feeding rate, and operating voltage, which are investigated experimentally in this work. The results show that a rotational speed of 750 rpm, a solution feeding rate of 0.5 mL h-1, and an operating voltage of 17 kV allow to obtain tissues with an average fiber diameter of 0.590 μm and porosity around 50%. The subsequent calcination processes are investigated through thermogravimetric analysis (TGA), which shows exothermic peaks due to solvent evaporation, debinding and perovskite structure formation, and suggest to perform calcination slowly in the temperature range 520-820 K. A fiber calcination process is carried out with a heating rate of 0.3 K min-1. Calcined fibers appear unbroken and visibly shrunk (post-calcination average diameter 0.31 μm), with a porosity of the calcined tissue of 51%. The morphological chacteristics of the LSCF calcined tissues are very promising for application in intermediate temperature solid oxide fuel cell (IT-SOFC) electrodes
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