177,653 research outputs found
I metodi basati sui flussi di risultato
No full textIl capitolo affronta il tema della stima del valore economico del capitale tramite i metodi basati sui flussi di risultato. Si trattano i due aspetti fondamentali di questi metodi: l’analisi qualitativa e l’analisi quantitativa. L’analisi qualitativa richiede la comprensione di cosa l’azienda è, di quale strategia potrà realisticamente perseguire in futuro e con quali capacità; l’analisi quantitativa converte ogni elemento descrittivo nella previsione dei fondamentali economici, finanziari e patrimoniali. Questi due aspetti sono intrinsecamente collegati e richiedono all’esperto capacità diagnostiche e adeguati modelli e tecniche interpretative
Il paradigma valutativo
No full textIl capitolo compara le varie finalità per cui si richiede una valutazione di azienda, sottolineando come il processo valutativo debba esser impostato coerentemente a queste finalità. In questo senso si caratterizza la figura dell’esperto di valutazione o valutatore rispetto ad altre figure professionali che possono essere interessate a determinare il valore di un’azienda, come il CFO e l’analista finanziario. Vengono sottolineati anche i rischi di errore e i condizionamenti che il valutatore può subire e come, in ogni caso, non si debba confondere il valore con il prezzo finale di una transazione. Il paradigma valutativo si fonda su diverse configurazioni di valore (valore economico, valore di mercato, valore d’investimento, ecc.), che esprimono valori aventi un diverso significato informativo, funzionale a diversi scopi conoscitivi nei diversi ambiti della valutazione. Inoltre, sono parte del paradigma valutativo le scelte inerenti i procedimenti tecnici per la valutazione d’azienda, che riguardano: (i) l’approccio, che può essere asset side o equity side, in ragione del fatto che si pervenga direttamente alla stima dell’equity value, oppure si valutino separatamente investimenti e posizione finanziaria netta; (ii) i metodi, che si articolano in tre categorie, a seconda che si basino sui risultati attesi, sui dati di mercato o sui costi di sostituzione. Si vedrà come le stime di capitale economico non possano esaurirsi nella semplicistica applicazione di una “formula” bensì siano la risultante di un articolato “processo di valutazione” nell’ambito del quale sono fasi imprescindibili la predisposizione della base informativa e l’analisi fondamentale. Anche per questo nella parte conclusiva del capitolo si mostreranno i principali errori in cui può incorrere il valutatore nello sviluppo del processo valutativo
Multi-objective optimization of a hydrogen production through the HyS process powered by solar energy in different scenarios
No full textThermochemical or hybrid cycles powered by concentrated solar energy are a very promising way to produce an effective clean hydrogen through the water splitting, in terms of greenhouse gas (GHG) emissions and power production sustainability. SOL2HY2 is an European project focused on this goal. It deepens the so-called HyS process in a closed or partially open version using a proper SO2 depolarized electrolyser, and moreover, it investigates key materials and process solutions, along the entire production chain. However, the identification of the best solution to obtain a suitable hydrogen in terms of cost, efficiency, availability of energy and material, sharing of renewable energy source, continuity of operation in different locations and plant sizes, poses many challenges in terms of flexibility and complexity of the system. In fact, it involves various chemical equipment, different solar and thermal storage technologies, and variable operative conditions with different reaction temperatures and mixture concentrations. Hence it arises the importance to have a tool for the investigation of this system. In this paper, data analysis and multi-objective techniques are used to study and optimize the process under consideration. Several mathematical methods have been exploited to make the best use of the available data, such as Design of Experiments techniques, meta-modeling strategies and genetic algorithms. All these methods have been implemented in the open source environments Scilab and R. © 2018 Hydrogen Energy Publications LL
Thermal energy storage with integrated heat exchangers using stratified molten salt system for 1 MWe CSP
No full textThermal energy storage (TES) optimization for Concentrated Solar Power (CSP) plants is a key component to improve dispatchability and power production, regardless of sunlight availability. ORC-PLUS, in the frame of Horizon2020, aims to deepen this aspect for an existing CSP plant coupled with a 1 MWe Organic Rankine Cycle (ORC) system, located in a desert area in Ben Guerir in Morocco and using linear Fresnel collectors as well as thermal oil as heat transfer fluid (HTF). In this context, it has been planned the implementation of a TES based on only one tank with molten salt and two integrated heat exchangers. This storage will be powered by an additional dedicated solar field. Aim of this paper is the analysis of the behaviour of the TES under different operating conditions using a proper computational model. © 2018 Author(s)
Integration of photovoltaic and concentrated solar thermal technologies for H2 production by the hybrid sulfur cycle
No full textIt is widely agreed that hydrogen used as energy carrier and/or storage media may significantly contribute in the reduction of emissions, especially if produced by renewable energy sources. The Hybrid Sulfur (HyS) cycle is considered as one of the most promising processes to produce hydrogen through the water-splitting process. The FP7 project SOL2HY2 (Solar to Hydrogen Hybrid Cycles) investigates innovative material and process solutions for the use of solar heat and power in the HyS process. A significant part of the SOL2HY2 project is devoted to the analysis and optimization of the integration of the solar and chemical (hydrogen production) plants. In this context, this work investigates the possibility to integrate different solar technologies, namely photovoltaic, solar central receiver and solar troughs, to optimize their use in the HyS cycle for a green hydrogen production, both in the open and closed process configurations. The analysis carried out accounts for different combinations of geographical location and plant sizing criteria. The use of a sulfur burner, which can serve both as thermal backup and SO2 source for the open cycle, is also considered. © 2017 Author(s)
Borohydride reduction of pyridinium salts. V. Thermal dimerization of 1,6-dihydro-1-methylpyridine-2-carbonitrile.
No full textThe 1,6-dihydropyridine I, obtained by NaBH4 redn. of 2-cyano-1-methylpyridinium iodide, undergoes a thermal dimerization to give the cyclobutane deriv. II. II rearranges, by heating, to the isomeric ethenonaphthyridine III (R = H). Label scrambling observed at 110 in III (R = H) reveals a degenerate thermal [3.3] sigmatropic shift
Hydrogen production by the solar-powered hybrid sulfur process: Analysis of the integration of the CSP and chemical plants in selected scenarios
No full textThe Hybrid Sulfur (HyS) is a water splitting process for hydrogen production powered with high temperature nuclear heat and electric power; among the numerous thermo-chemical and thermo-electro-chemical cycles proposed in the literature, such cycle is considered to have a particularly high potential also if powered by renewable energy. SOL2HY2 (Solar to Hydrogen Hybrid Cycles) is a 3 year research project, co-funded by the Fuel Cells and Hydrogen Joint Undertaking (FCH JU). A significant part of the project activities are devoted to the analysis and optimization of the integration of the solar power plant with the chemical, hydrogen production plant. This work reports a part of the results obtained in such research activity. The analysis presented in this work builds on previous process simulations used to determine the energy requirements of the hydrogen production plant in terms of electric power, medium (550°C) temperature heat. For the supply of medium temperature (MT) heat, a parabolic trough CSP plant using molten salts as heat transfer and storage medium is considered. A central receiver CSP (Concentrated Solar Power) plant is considered to provide high temperature (HT) heat, which is only needed for sulfuric acid decomposition. Finally, electric power is provided by a power block included in the MT solar plant and/or drawn from the grid, depending on the scenario considered. In particular, the analysis presented here focuses on the medium temperature CSP plant, possibly combined with a power block. Different scenarios were analysed by considering plants with different combinations of geographical location and sizing criteria. © 2016 Author(s)
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