The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Aristide F Massardo - One of the best experts on this subject based on the ideXlab platform.
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emulator rig for sofc hybrid systems Temperature and power control with a real time software
Fuel Cells, 2013Co-Authors: Francesco Caratozzolo, Mario L Ferrari, Alberto Traverso, Aristide F MassardoAbstract:This work is based on the hybrid system emulator plant developed by the Thermochemical Power Group (TPG) of the University of Genoa. This rig is composed of a 100 kW microturbine coupled with high Temperature Fuel Cell emulation devices. A real-time model is used for components not physically present in the laboratory (solid oxide Fuel Cell (SOFC), reformer, anodic circuit, off-gas burner, cathode blower). It is necessary to evaluate thermodynamic and electrochemical performance related to SOFC systems. Using an User Datagram Protocol (UDP) based connection with the control/acquisition software, it generates a hardware-in-the-loop (HIL) facility for hybrid system emulation. Temperature, pressure, and mass flow rate at the recuperator outlet and machine rotational speed are measured in the plant and used as inputs for the model. The turbine outlet Temperature (TOT) calculated by the model is fed into the machine control system and the turbine electric load is changed to match the model TOT values (effective plant/model coupling to avoid modifications on microturbine controller). Different tests were carried out to analyze hybrid system technology through the interaction between an experimental plant and a real-time model. Double step and double ramp tests of current and Fuel provided the system dynamic response.
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recuperator dynamic performance experimental investigation with a microgas turbine test rig
Applied Energy, 2011Co-Authors: Mario L Ferrari, Matteo Pascenti, Alessandro Sorce, Aristide F MassardoAbstract:The aim of this work is the experimental analysis of steady-state and transient behavior of a primary surface recuperator installed in a 100kW commercial microgas turbine (mGT). The machine is integrated in an innovative test rig for high Temperature Fuel Cell hybrid system emulation. It was designed and installed by the Thermochemical Power Group (TPG), at the University of Genoa, within the framework of the Felicitas and LARGE-SOFC European Integrated Projects. The high flexibility of the rig was exploited to perform tests on the recuperator operating in the standard cycle. Attention is mainly focused on its performance in transient conditions (start-up operations and load rejection tests). Start-up tests were carried out in both electrical grid-connected and stand-alone conditions, operating with different control strategies. Attention is focused on system response due to control strategy and on boundary Temperature variation because of its influence on component life consumption.
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hybrid system test rig start up and shutdown physical emulation
Journal of Fuel Cell Science and Technology, 2010Co-Authors: Mario L Ferrari, Matteo Pascenti, Loredana Magistri, Aristide F MassardoAbstract:The University of Genoa (TPG) has designed and developed an innovative test rig for high Temperature Fuel Cell hybrid system physical emulation. It is based on the coupling of a modified commercial 100 kW recuperated micro gas turbine to a special modular volume designed for the experimental analysis of the interaction between different dimension Fuel Cell stacks and turbomachines. This new experimental approach that generates reliable results as a complete test rig also allows investigation of high risk situations with more flexibility without serious and expensive consequences to the equipment and at a very low cost compared with real hybrid configurations. The rig, developed with the support of the European Integrated Project "FELICITAS," is under exploitation and improvement in the framework of the new European Integrated Project "LARGE-SOFC" started in January 2007. The layout of the system (connecting pipes, valves, and instrumentation) was carefully designed to minimize the pressure loss between compressor outlet and turbine inlet to have the highest plant flexibility. Furthermore, the servocontrolled valves are useful for performing tests at different operative conditions (i.e., pressures, Temperatures, and pressure losses), focusing the attention on surge and thermal stress prevention. This work shows the preliminary data obtained with the machine connected to the volume for the test rig safe management to avoid surge or excessive stress, especially during the critical operative phases (i.e., start-up and shutdown). Finally, the attention is focused on the valve control system developed to emulate the start-up and shutdown phases for high Temperature Fuel Cell hybrid systems. It is necessary to manage the flows in the connecting pipes, including an apt recuperator bypass, to perform a gradual heating up and cooling down as requested during these phases. It is an essential requirement to avoid thermal stress for the Fuel Cell stack. For this reason, during the start-up, the volume is gradually heated by the compressor outlet flow followed by a well managed recuperator outlet flow and vice versa for the shutdown. Furthermore, operasing with a constant rotational speed control system, the machine load is used to reach higher Temperature values typical of these kinds of systems.
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design and testing of ejectors for high Temperature Fuel Cell hybrid systems
Journal of Fuel Cell Science and Technology, 2006Co-Authors: Mario L Ferrari, Davide Bernardi, Aristide F MassardoAbstract:Our goal in this work is the improvement of the ejector performance inside hybrid systems supporting the theoretical activity with experimental tests. In fact, after a preliminary ejector design, an experimental rig has been developed to test single stage ejectors for hybrid systems at different operative conditions of mass flow rates, pressures, and Temperatures. At first, an open circuit has been built to perform tests at atmospheric conditions in the secondary duct. Then, to emulate a SOFC anodic recirculation device, the circuit has been closed, introducing a Fuel Cell volume in a reduced scale. This configuration is important to test ejectors at pressurized conditions, both in primary and secondary ducts. Finally, the volume has been equipped with an electrical heater and the rig has been thermally insulated to test ejectors with secondary flows at high Temperature, necessary to obtain values in similitude conditions with the real ones. This test rig has been used to validate simplified and CFD models necessary to design the ejectors and investigate the internal fluid dynamic phenomena. In fact, the application of CFD validated models has allowed us to improve the performance of ejectors for hybrid systems optimizing the geometry in terms of primary and secondary ducts, mixing chamber length, and diffuser. However, the simplified approach is essential to start the analysis with an effective preliminary geometry.
Ermete Antolini - One of the best experts on this subject based on the ideXlab platform.
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graphene as a new carbon support for low Temperature Fuel Cell catalysts
Applied Catalysis B-environmental, 2012Co-Authors: Ermete AntoliniAbstract:Abstract Highly dispersed catalysts on a conductive support, commonly platinum and platinum-based catalysts, are used as electrode materials in low-Temperature Fuel Cells. Carbon blacks are commonly used as Fuel Cell catalysts supports, but their properties are not completely satisfactory. Thus, in the last years carbon black alternative materials such as nanostructured carbons, ceramic and polymer materials have been proposed as Fuel Cell catalyst supports. Very recently, in consideration of their high surface area, high conductivity, unique graphitized basal plane structure and potential low manufacturing cost, graphene nanosheets have been investigated as a support for low-Temperature Fuel Cell catalysts. This paper presents an overview of graphene nanosheets used as supports for Fuel Cell catalysts. In particular, the catalytic activity and durability of catalysts supported on graphene are compared with those of catalysts supported on the commonly used carbon blacks and on carbon nanotubes, that is, on rolled graphene.
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polymer supports for low Temperature Fuel Cell catalysts
Applied Catalysis A-general, 2009Co-Authors: Ermete Antolini, E R GonzalezAbstract:Due to their high accessible surface area, low resistance and high stability, conducting polymers have been investigated as carbon-substitute supports for Fuel Cell catalysts. The main reason for incorporating metallic particles into porous polymeric matrixes is to increase the specific area of these materials and thereby improve the catalytic efficiency. Polymer-supported metal particles also present higher tolerance to poisoning due to the adsorption of CO species, in comparison to the serious problem of poisoning of bulk and carbon-supported metals. Moreover, conducting polymers are not only electron conducting, but also proton conducting materials, so they can replace Nafion in the catalyst layer of Fuel Cell electrodes and provide enhanced performance. This paper provides a review of the state-of-the-art in the development of metal/polymer composites as electrode materials for low-Temperature Fuel Cells.
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ceramic materials as supports for low Temperature Fuel Cell catalysts
Solid State Ionics, 2009Co-Authors: Ermete Antolini, E R GonzalezAbstract:The performance and durability of low-Temperature Fuel Cells seriously depend on catalyst support materials. Catalysts supported on high surface area carbons are widely used in low Temperature Fuel Cells. However, the corrosion of carbonaceous catalyst-support materials such as carbon black has been recognized as one of the causes of performance degradation of low-Temperature Fuel Cells, in particular under repeated start-stop cycles or high-potential conditions. To improve the stability of the carbon support, materials with a higher graphitic character such as carbon nanotubes and carbon nanofibers have been tested in Fuel Cell conditions. These nanostructured carbons show a several-fold lower intrinsic corrosion rate, however, do not prevent carbon oxidation, but rather simply decrease the rate. Due their high stability in Fuel Cell environment, ceramic materials (oxides and carbides) have been investigated as carbon-substitute supports for Fuel Cell catalysts. Moreover, the higher specific electrocatalytic activity of some ceramic supported metals than unsupported and carbon supported ones, suggests the possibility of a synergistic effect by supporting metal catalyst on ceramic supports. This paper presents an overview of ceramic materials tested as a support for Fuel Cell catalysts, with particular attention addressed to the electrochemical activity and stability of the supported catalysts.
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carbon supports for low Temperature Fuel Cell catalysts
Applied Catalysis B-environmental, 2009Co-Authors: Ermete AntoliniAbstract:Abstract To increase their electrochemically active surface area, catalysts supported on high surface area materials, commonly carbons, are widely used in low-Temperature Fuel Cells. Recent studies have revealed that the physical properties of the carbon support can greatly affect the electrochemical properties of the Fuel Cell catalyst. It has been reported that carbon materials with both high surface area and good crystallinity can not only provide a high dispersion of Pt nanoparticles, but also facilitate electron transfer, resulting in better device performance. On this basis, novel non-conventional carbon materials have attracted much interest as electrocatalyst support because of their good electrical and mechanical properties and their versatility in pore size and pore distribution tailoring. These materials present a different morphology than carbon blacks both at the nanoscopic level in terms of their pore texture (for example mesopore carbon) and at the macroscopic level in terms of their form (for example microsphere). The examples are supports produced from ordered mesoporous carbons, carbon aerogels, carbon nanotubes, carbon nanohorns, carbon nanocoils and carbon nanofibers. The challenge is to develop carbon supports with high surface area, good electrical conductivity, suitable porosity to allow good reactant flux, and high stability in Fuel Cell environment, utilizing synthesis methods simple and not too expensive. This paper presents an overview of carbon supports for Pt-based catalysts, with particular attention on new carbon materials. The effect of substrate characteristics on catalyst properties, as electrocatalytic activity and stability in Fuel Cell environment, is discussed.
Peichen Su - One of the best experts on this subject based on the ideXlab platform.
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sputtered nanoporous ptni thin film cathodes with improved thermal stability for low Temperature solid oxide Fuel Cells
Electrochimica Acta, 2017Co-Authors: K Y Liu, Seong Hyuk Lee, Yongjin Yoon, Peichen SuAbstract:Abstract Nanoporous PtNi alloy thin film was demonstrated to effectively improve the thermal stability of cathode under high Temperature Fuel Cell operation. The grain growth, which indicates the agglomeration of the nanoparticles, were constrained, as observed by comparing the surface morphologies and grain sizes in bulk of film between pure Pt and PtNi alloy cathodes. The constrained grain growth by alloying with Ni maintained the porosity in bulk of cathode film for sufficient cathode oxygen diffusion and adsorption/dissociation processes. Fuel Cell using Pt 67 -Ni 33 cathode better maintained the output current density than the Cell using pure Pt cathode by 26% after 48 hours of continuous operation.
Bengt Sunden - One of the best experts on this subject based on the ideXlab platform.
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simulation of alternative Fuels for potential utilization in solid oxide Fuel Cells
International Journal of Energy Research, 2011Co-Authors: Hedvig Paradis, Martin Andersson, Jinliang Yuan, Bengt SundenAbstract:Fuel Cells are promising with advantages of higher energy conversion efficiency and lower emissions of SOX, NOX, and CO2 than conventional power systems. Solid oxide Fuel Cell (SOFC) is a high Temperature Fuel Cell, which operates at 873-1273 K. This allows SOFCs to operate with different types of Fuels from both fossil and renewable sources because of their general higher tolerance to contaminants than other Fuel Cells. It opens up for an easier transition from conventional power generation of hydrocarbon-based Fuels to hydrogen energy by Fuel Cells. With increased interest in the use of renewable Fuels, Fuel Cells have the potential to play a significant role in a sustainable solution. Attractive Fuels, which are reviewed here and analyzed through thermodynamic calculations in this study, are methanol, ethanol, di-methyl-ether, and biogas. It is concluded that it is feasible for SOFCs to handle all the studied Fuels. Further, a CFD model of an anode-supported SOFC is simulated with biogas as Fuel. An analysis of the Fuels is conducted at 1000 K, in terms of the heat required for each mole H-2 converted. It shows that methane uses twice as much heat as methanol and di-methyl-ether do, and if efficiently distributed where needed, it can work as a possible performance enhancement. A composed table of comparable studies in the literature of different alternative Fuels is provided. The case study of an anode-supported SOFC Fueled with biogas of varying amount of methane and steam-to-Fuel ratio revealed that biogas needs a high inlet Temperature to enable the reforming and keep a constant current density distribution. Copyright (C) 2011 John Wiley & Sons, Ltd. (Less)
J Tenreiro - One of the best experts on this subject based on the ideXlab platform.
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design of a trigeneration system using a high Temperature Fuel Cell
International Journal of Energy Research, 2009Co-Authors: Isabel Malico, A P Carvalhinho, J TenreiroAbstract:Fuel Cells are one of the technologies available for combined heat, cooling and power production (CHCP) systems. They offer several advantages over more conventional systems, but they still need to overcome a number of barriers until they are readily available for commercialization. At this stage, it is important to fund demonstration projects that experiment with Fuel Cell technology in pre-commercial situations. In this context, a CHCP system, using a high-Temperature Fuel Cell (solid oxide Fuel Cells, SOFC) and an absorption chiller, was designed in order to meet the energetic demands of a hospital for electricity, cooling, heating and hot water. The hospital load profile was determined taking into consideration the hourly energy consumption for four different typical days in the year. The CHCP system was designed so that the Fuel Cell meets the electrical demand of the hospital and, since the SOFC did not produce enough thermal energy, a boiler was considered. The artificial thermal efficiency of the CHCP system is 68%. The investment analysis is presented and it is concluded that, at the present and at three other scenarios, the system is not financially feasible. Despite this conclusion, it is important to invest on demonstration projects to help Fuel Cells reach commercialization. Copyright © 2008 John Wiley & Sons, Ltd.
