1,720,979 research outputs found
MCFC and microturbine power plant simulation
No full textThe consistent problem of the CO2 emissions and the necessity to find new energy sources, are motivating the scientific research to use high efficiency electric energy production's technologies that could exploit renewable energy sources too. The molten carbonate fuel cell (MCFC) due to its high efficiencies and low emissions seems a valid alternative to the traditional plant. Moreover, the high operating temperature and pressure give the possibility to use a turbine at the bottom of the cells to produce further energy, increasing therefore the plant's efficiencies. The basic idea using this two kind of technologies (MCFC and microturbine), is to recover, via the microturbine, the necessary power for the compressor, that otherwise would remove a consistent part of the MCFC power generated. The purpose of this work is to develop the necessary models to analyze different plant configurations. In particular, it was studied a plant composed of a MCFC 500 kW Ansaldo at the top of a microturbine 100 kW Turbec. To study this plant it was necessary to develop: (i) MCFC mathematical model, that starting from the geometrical and thermofluidodynamic parameter of the cell, analyze the electrochemical reaction and shift reaction that take part in it; (ii) plate reformer model, a particular compact reformer that exploit the heat obtained by a catalytic combustion of the anode and part of cathode exhausts to reform methane and steam; and (iii) microturbine-compressor model that describe the efficiency and pressure ratio of the two machines as a function of the mass flow and rotational regime. The models developed was developed in Fortran language and interfaced in Chemcad© to analyze the power plant thermodynamic behavior. The results show a possible plant configuration with high electrical and global efficiency (over 50 and 74%). © 2006 Elsevier B.V. All rights reserved
Oltre il PIL:nuovi indicatori di benessere e sostenibilità dello sviluppo
No full textThe paper underlines the importance of overcoming the estimation of GDP based on old criteria and try to identify a new way of evaluation on the basis of the literature reviewe
Process simulation of a neutral emission plant using chestnut's coppice gasification and molten carbonate fuel cells
No full textThe problem of CO2 emissions and the need to find new energy sources sources are pushing scientific research toward the use of high efficiency technologies for electric power generation that can exploit renewable energy sources - potentially neutral for the environment in terms of greenhouse gas emissions. Process simulations of advanced plants fed by biomass are a key step to develop renewable resources based high temperature fuel cell applications. The aim of this work is to predict the component behavior of a specific power plant mainly composed of a gasifier, a molten carbonate fuel cell (MCFC), and a micro-gas-turbine (mGT) and fed by chestnut coppice, waste available in great quantity in Central Italy, as well as in several other European regions. The gasifier produces a gas with a high content of hydrogen and low content of char and tar. This syngas is exploited by the MCFC-mGT plant. The mGT using the MCFC cathode outlet gases, shows through simulation to be able to operate the air compressor and produce further electrical power Particular models for the MCFC and gasifier have been developed in FORTRAN by the authors and then interfaced to commercial software (CHEMCAD©) to simulate the plant's thermodynamic behavior. The results show the possibility of an extremely interesting "carbon neutral" plant configuration with high electrical and global efficiency (respectively, 41% and 86%), exclusively based on the use of renewable resources (biomass). Copyright © 2008 by ASME
The Concept of Energy Traceability: Application to EV Electricity Charging by Res
Full text linkAbstractThe energy sustainability, in the era of sources diversification [1], can be guaranteed by an energy resources utilization most correct, foreseeing no predominance of one source over the others in any area of the world but a proper energy mix, based on locally available resources and needs [2]-[4]. In this scenario, manageable with a smart grid system [5], [6], a virtuous use of RES must be visible, recognizable and quantifiable, in one word traceable [7]. The innovation of the traceability concept consists in the possibility of having information concerning the exact origin of the electricity used for a specific end use, in this case EV charging [8]. The traceability, in a context of increasingly sustainability [9], [10] and smartness city, is an important develop tool because only in this way it is possible to quantify the real emissions produced by EVs and to ensure the real foresight of grid load. This paper wants investigate the real ways to introduce this kind of real energy accounting, through the traceability
Hydrides for submarine applications: overview and identification of optimal alloys for air independent propulsion maximization
No full textThis study identifies possible alternatives in the currently use of hydrides in submarine
applications in order to increase the storage capacity and, therefore, the autonomy (Air In-
dependent Propulsion) of the boat. The study proposes a plug and play solution which re-
quires no changes for what concerning the current propulsion system, nor the auxiliary
systems of absorption and desorption of hydrogen, nor the power supply system of fuel cells.
Different constraints have been taken into account, as the storage volume density, the
operatingconditions (pressureandtemperature),thenumberofchargeanddischarge cycles.
Taking into account that it is desirable to maintain the set-up of the actual systems (for what
concerning the spaces, the pressure and temperature) the solution obtained in the present
study ranges in between the following target values: 120 g/dm3
for the storage capacity involume; 20e50C for the operating temperature, 2e3 bar for the hydrogen desorption pres-
sure and 150 charge and discharge cycles that can ensure 5 cycles per year for 30 years. Under
these constraints, a significant increase of the autonomy of the boat has been evaluated
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Linking Smartness and Sustainability for a more intelligent world
No full textSustainability and Sustainable Development are becoming increasingly relevant in the global agenda of governments as well as businesses and civil society. They should be among the top priorities of what we would consider a really Smarter Planet.
The concept of smartness is widely used essentially to refer to digitalized processes and telematic interactions in several fields of social, environmental, and economic human activities. Sustainability is used to define successful human activities, processes and interactions from a social-environmental-economic point of view. Although both the concepts imply multi-disciplinary views that include economic, social and environmental sciences, the smartness and sustainability perspectives have different focus: the smartness perspective is more focused on socio-technical systems (Trist, 1981), hence on interaction between humans and technology; the sustainability perspective is more focused on social-ecological systems (Berkes et al., 2003; Ostrom, 2009), hence on interaction between humans and nature.
By focusing on the relationship between socio-technical and social-ecological systems, two key research questions emerge: What is the relationship between smartness and sustainability? Is a smarter planet also more sustainable
Critical review of fuel cell's membranes and identification of alternative types for automotive applications
No full textHydrogen is considered one of the most important energy vector of the future and fuel in
transport sector. The Fuel Cells (FCs) Traction System present some advantages respect to
the traditional traction engine, consisting in lower emissions and noise. The more suitable
Fuel Cells in automotive applications are those that use Polymer Electrolyte Membrane
(PEM). The main obstacles to the commercialization of PEM fuel cells are largely concerning
the cost, mechanical weakness and low durability of the membranes with increasing
temperature. This latter aspect in particular referring to the fact that water is present in the
membranes, thereby limiting the operating temperature of a fuel cell, which on average is
about 80 C. This in turn results in lower performance of the fuel cells due to a slower
kinetics of electrodes and essentially no CO tolerance. It can groped to improve the performance
of a PEM increasing the temperature above 100 C, changing the membrane type
making it resistant to the natural increase in temperature of the system so as to improve
the electrodes kinetics. The present work has the purpose of highlighting the orientation of
the current research towards the development of specific types of membrane for the FC
performance improvement
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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