• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.722-729
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• 2005

Design analysis of the solid oxide fuel cell and gas turbine combined power system is performed considering different methods for preheating cell inlet air. The purpose of air preheating is to keep the temperature difference between cell inlet and outlet within a practical design range thus to reduce thermal stress inside the cell. Three different methods considered are (1) adopting a burner in front of the cell, (2) adopting a preheater (heat transfer from the main combustor) in front of the cell and (3) using recirculation of the cathode exit gas. For each configuration, analyses are carried out for two values of allowable maximum cell temperature difference. Performance characteristics of all cases are compared and design limitations are discussed. Relaxation of the cell temperature difference (larger difference) is proved to ensure higher efficiency. Recirculation of the cathode exit gas exhibits better performance than other methods and this advantage becomes more prominent as the constraint of the cell temperature difference becomes more severe (smaller temperature difference).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.11
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• pp.849-855
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• 2008

The paper addresses modeling and analysis of the part load performance of a hybrid fuel cell system integrating a polymer electrolyte membrane fuel cell(PEMFC) and a gas turbine(GT). The system is a pressurized one where the working pressure of the PEMFC is higher than the ambient pressure. In addition to the two major components, the system also includes auxiliary parts such as a steam reformer, a humidifier, and afterburner and so on. Based on design analysis, component off-design models are incorporated in the analysis program and part load operation is simulated. The mode for the part load operation of the PEMFC/GT hybrid system is a variable rotational speed operation. The operating characteristics and variations in the system efficiency and component performance parameters at part load are analyzed.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.893-905
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• 2016

Numerous advanced reactor concepts have been proposed to replace light water reactors ever since their establishment as the dominant technology for nuclear energy production. While most designs seek to improve cost competitiveness and safety, the implausibility of doing so with affordable materials or existing nuclear fuel infrastructure reduces the possibility of near-term deployment, especially in developing countries. The organic nuclear concept, first explored in the 1950s, offers an attractive alternative to advanced reactor designs being considered. The advent of high temperature fluids, along with advances in hydrocracking and reforming technologies driven by the oil and gas industries, make the organic concept even more viable today. We present a simple, cost-effective, and safe small modular nuclear reactor for offshore underwater deployment. The core is moderated by graphite, zirconium hydride, and organic fluid while cooled by the organic fluid. The organic coolant enables operation near atmospheric pressure and use of plain carbon steel for the reactor tank and primary coolant piping system. The core is designed to mitigate the coolant degradation seen in early organic reactors. Overall, the design provides a power density of 40 kW/L, while reducing the reactor hull size by 40% compared with a pressurized water reactor while significantly reducing capital plant costs.