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

In thermo-fluid-dynamics, the important role played by the boundary layer phenomena is well known. In order to set up an experimental tool, able to measure fluid dynamic magnitudes in the boundary layer, many efforts have been made and some advanced measurements have been developed. Since the midsixties, infrared thermography has been applied as a measurement technique. Primarily, this technique was used in space missions where the protection of space vehicles in the reentry phase was of prime importance. Nowadays, thermography is one of the most advanced non-intrusive measurement techniques and presents many advantages such as no-needs for particular settings of system under analysis. Therefore, considering that boundary layer continues to be a fundamental aspect in fluid-dynamics studies, the present work wants to dwell on the possibility to enlarge the application of the infrared measurement technique, in particular for subsonic flows in passive mode. These conditions point out important problems of measurement for the low energy content and for the type of thermal exchange that can not be simplified as it is traditionally made in supersonic flows. Either the possibility to operate with modern infrared cameras or the improvements of new theoretical models in the data reduction process will be described in this paper and an application to an airfoil will be presented. The measurement technique used in this paper can be applied to any aerodynamic profile and can be easily used as a non intrusive technique to characterize the flow fields of blade cascades for gas tubrines and turbomachinery in general. NOMENCLATURE

High Resolution Infrared Thermography for Airfoils Boundary Layer Inspection in Passive Mode

The Humid Air Turbine (HAT) cycle is an inter-cooled gas turbine cycle, having an air-water mixing evaporator before the combustion chamber, and a heat recovering system for the exhaust gases. The considerable amount of water consumed in the mixing evaporator (about 1,200--2,400 m{sup 3} daily for a 100 MW unit), represents a significant drawback to the use of the HAT cycle as well as of other steam injected gas turbines. In fact, this means high operational costs for water treatment, and eventual legislative restrictions limiting the use of water, not to mention the environmental impact of the depletion of water resources. The aim of this paper is to evaluate the changes in the performance of the HAT cycle when a water recovery system is added in the exhaust gases, and to determine the heat exchangers conditions for maximum water and heat recovery. Finally, the size of a surface condenser for water recovery is determined for a given HAT cycle power output. The results show the possibility to recover up to 85% of the consumed water and up to 30% of input heat from the condensation of the water contained in the exhaust gas. The paper also examines all the thermodynamicmore » processes in each cycle component from the viewpoint of recovering water from the exhaust gas. Since part of the water contained in the exhaust gas is due to the inlet air humidity and the combustion process, the relative amount of water and their contributions to the overall heat recovery are also calculated.« less

Thermodynamic Analysis of Injected Water Recovery Systems for the Humid Air Turbine (HAT) Cycle


 Small scale Internal Combustion Engines (ICE) powered Combined Heat and Power (CHP) plants are economically convenient when availability and efficiencies are above specified limits. Nevertheless these plants are often run without a monitoring device capable of data storing and trending and of performance evaluation.
 This paper describes the setting up of a powerful low-cost monitoring system for the CHP plant that powers the School of Engineering of the University of Perugia. Data acquisition is performed by interfacing a Personal Computer (PC) to existing control panels via, serial port, and to a data acquisition board for those variables that are not measured by existing devices. Performance indexes are then calculated via software. Alarms and controls are stored as well to set up a database for diagnostic purposes.
 The monitoring itself has already shown its troubleshooting capability in interface to maintenance personnel: history trending of variables speeds up the phase of failure identification because it eliminates those possibilities that are negated by cross referencing values of different variables.

Umberto Desideri

Papers

High Resolution Infrared Thermography for Airfoils Boundary Layer Inspection in Passive Mode

Thermodynamic Analysis of Injected Water Recovery Systems for the Humid Air Turbine (HAT) Cycle

LO.CO.MO.DIA. Low Cost Monitoring for Diagnostic Purposes of a Small Scale CHP Plant

Distributed generation of electricity from biomass using pyrolysis technology.

Micro-Turbine Fuelled By Pyrolysis Gas Thermodynamic Analysis