Impedance spectroscopy provides the opportunity for in-situ identification and quantification of physical processes and has been used extensively to study the behavior of the fuel cell. However, a key question to be answered is whether the features seen in the impedance response are caused by an artifact or represent a physical process taking place in …

Continue reading »

A 5-l0kW Solid Oxide Fuel Cell for Distributed Generation requires a DC/DC converter topology that boasts high efficiency and reduced cost. The Zero-Voltage-Switching Phase-Shift-Modulated Full-Bridge ZVS-PSM-FB) topology meets these criteria at heavy load, but incurs switching losses at lighter loads which decrease its efficiency. This thesis presents a new family of multi-bridge DC/DC converter topologies …

Continue reading »

Fossil fuels provide approximately 80% of the worlds energy demands. Methods for reducing CO2 emissions resulting from fossil fuels include increasing the efficiency of power plants and production processes, decreasing energy demands, in combination with CO2 capture and long term storage CCS). CO2 capture technologies include post-combustion, pre-combustion, and oxyfuel combustion. The amine-based post-combustion CO2 …

Continue reading »

Presently, there is broad world interest in advancing the characterization, understanding, and use of biofuels, which are produced from a variety of cellulosic sources or organic matter, as they constitute one of the most viable and affordable partial solutions to reduce dependence on conventional petroleum. Additionally, they are more environmentally friendly as their use produces …

Continue reading »

As an energy storage device, the flywheel has significant advantages over conventional chemical batteries, including higher energy density, higher efficiency, longer life time, and less pollution to the environment. An effective flywheel system can be attributed to its good motor/generator (M/G) design. This thesis describes the research work on the design of a permanent magnet …

Continue reading »

Development and extraction of energy sources, energy production and energy use have huge economic, environmental and geopolitical impacts. Increasing energy demands in tandem with reductions in fossil fuel production has led to significant investments in research into alternative forms of energy. One that is promising but yet not commercially established is the production of biofuel …

Continue reading »

Earthquake protective systems have been developed in recent decades to minimize the damage occurring to civil engineering structures, especially to buildings and bridges during an earthquake. The technology of earthquake protective systems can be further subcategorized into fields of passive, semi active and active energy dissipation systems. The aim of this dissertation is to develop …

Continue reading »

Previous work had been done at the Energy Research Center to develop and test numerical software for modeling condensing heat exchangers. This software was used to numerically simulate the results from an experimental condensing heat exchanger which used bare tube heat exchangers, with coal fired flue gas on the outside of the tubes, and cooling …

Continue reading »

Gordon Moore famously predicted the exponential increase in transistor integration and computing power that has been witnessed in recent decades [1]. In the near future, it is expected that more than one billion transistors will be integrated per chip, and advanced microprocessors will require clock speeds in excess of several GHz. The increasing number of …

Continue reading »

This research details the development of a small signal model of an high voltage DC (HVDC) terminal and analysis of the HVDC terminal interactions by using small signal techniques. The modeling requirements to adequately represent the dynamics of the HVDC converters and AC networks are investigated. The derived small signal model of the HVDC system …

Continue reading »