The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

Framework Convention on Climate Change

Capture and sequestration of CO2 from fossil fuel power plants is gaining widespread interest as a potential method of controlling greenhouse gas emissions. Performance and cost models of an amine (MEA)-based CO2 absorption system for postcombustion flue gas applications have been developed and integrated with an existing power plant modeling framework that includes multipollutant control technologies for other regulated emissions. The integrated model has been applied to study the feasibility and cost of carbon capture and sequestration at both new and existing coal-burning power plants. The cost of carbon avoidance was shown to depend strongly on assumptions about the reference plant design, details of the CO2 capture system design, interactions with other pollution control systems, and method of CO2 storage. The CO2 avoidance cost for retrofit systems was found to be generally higher than for new plants, mainly because of the higher energy penalty resulting from less efficient heat integration as well ...

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A technical, economic, and environmental assessment of amine-based CO2 capture technology for power plant greenhouse gas control

Solar Engineering Of Thermal Processes

Global environmental concerns and the escalating demand for energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Solar energy is the most abundant, inexhaustible and clean of all the renewable energy resources till date. The power from sun intercepted by the earth is about 1.8 × 1011 MW, which is many times larger than the present rate of all the energy consumption. Photovoltaic technology is one of the finest ways to harness the solar power. This paper reviews the photovoltaic technology, its power generating capability, the different existing light absorbing materials used, its environmental aspect coupled with a variety of its applications. The different existing performance and reliability evaluation models, sizing and control, grid connection and distribution have also been discussed. © 2011 Published by Elsevier Ltd.

A review of solar photovoltaic technologies

Liquid biofuels, such as bioethanol, biodiesel and vegetal oils, can effectively be used in internal combustion engines blended with liquid fuels of fossil origin or in their substitution, allowing a reduction of CO2 and pollutant emissions in the atmosphere. This work is supported by a CFD analysis to study the feasibility of using these fuels derived from biomass in a 80 kWel micro gas turbine, originally designed for operation with natural gas. In this paper preliminary results about the behavior of bioethanol in the MGT combustion chamber are presented. The complete investigation however includes biodiesel and also glycerin, a byproduct of biodiesel production. To carry out the computational simulations, combustion models included in a commercial software and oxidation mechanism of ethanol taken from the literature were used. The geometry of the NG injector was modified to optimize the liquid inlet into the combustor. Simulation results in terms of temperatures, pressures, and emissions were compared with data available for natural gas combustion in the original combustion chamber.Copyright © 2013 by ASME

CFD Analysis of an Annular Micro Gas Turbine Combustion Chamber Fuelled With Liquid Biofuels: Preliminary Results With Bioethanol

Simulation code for design and off design performance prediction of geothermal power plants

Slow pyrolysis of waste and biomass may represent an interesting solution for renewable energy conversion in highly regenerative Gas Turbine (GT) or Internal Combustion Engines (ICE) based power cycles. The combined production of a medium LHV gas to fuel the GT or the ICE and of a high LHV byproduct (tar and/or char) that may contribute to maintain the pyrolysis process, makes pyrolysis highly competitive when compared to gasification. Nevertheless few simulations of such integrated plants are available in literature also because of the lack of general and robust modeling tools for the pyrolysis process. A pilot scale rotary kiln pyrolyzer was built at the University of Perugia to investigate the main benefits and drawbacks of the technology. The pyrolyzer will provide the experimental data that are necessary both to evaluate mass and energy balances, and to support the pyrolysis simulation activity that the authors are carrying out. Namely the test rig will provide, for each given quantity and composition of the biomass or waste in input, the gas, char and tar yields and compositions and the energy provided to maintain the process. This paper describes the main features and operational possibilities of the plant.Copyright © 2004 by ASME

Micro Scale Slow-Pyrolysis Rotary Kiln for Syngas and Char Production From Biomass and Waste: Design and Construction of a Reactor Test Bench

Fuel cells have resulted to be very attractive power generation systems, promising highly efficient electricity generation with very low environmental impact. Although still in embryonic infancy high-temperature fuel cells, the very high energetic efficiency can be further increased by their integration in hybrid cycles. While a wide variety of potential bottoming technologies for exploiting the high temperature exhaust gases waste heat is available, a lot of research effort is needed to determine the optimal integration of well established technologies with these very novel conversion devices. This work, using results from previous works, in which a MCFC/Gas Turbine hybrid plant was defined and the working parameters optimised both with a GT simple cycle and with steam injection and post combustion, starts from choosing an existing gas turbine technology with suitable working parameters to perform a system evaluation and integration. Since the gas turbine nominal maximum temperature cannot be reached by the only means of heat exchange from the MCFC plant section, post combustion has been considered and the turbine has been simulated both in nominal and in off design conditions in order to find an optimal solution. The work takes into consideration not only the main plants modifications of the existing components to allow for system integration but also the most relevant issues connected with altered working conditions.Copyright © 2002 by ASME

Umberto Desideri

Papers

CFD Analysis of an Annular Micro Gas Turbine Combustion Chamber Fuelled With Liquid Biofuels: Preliminary Results With Bioethanol

Simulation code for design and off design performance prediction of geothermal power plants

Micro Scale Slow-Pyrolysis Rotary Kiln for Syngas and Char Production From Biomass and Waste: Design and Construction of a Reactor Test Bench

Feasibility and Performance of an Ambient Pressure MCFC Combined With a Commercial Gas Turbine

Performance Analysis of Gas Turbines Operating at Different Atmospheric Conditions