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Advances in tubular solid oxide fuel cell technology

Description: This document provides the functional design criteria for an addition to the 222-S facility. This project will provide space for manipulator repair, equipment and manipulator decontamination and laundry storage. The manipulator repair and storage area will provide for storage of 20 manipulators, an area for receiving potentially contaminated manipulators and an area for the repair of manipulators. The decontamination area will be capable of decontamination of manipulators and shipping casks, pigs, T-handle carriers and other shipping containers. The laundry storage area will provide space for potentially contaminated and clean laundry.
Date: March 1, 1995
Creator: Singhal, S.C.
Partner: UNT Libraries Government Documents Department

Zirconia-based fuel cells for power generation

Description: This paper reviews the design and operation of the high temperature solid oxide fuel cells based on yttria-stabilized zirconia electrolyte. The functional requirements of the various cell components are presented; and the materials and fabrication processes used for different cell components are described. Finally, the recent progress made toward commercialization of these cells for clean and efficient power generation is discussed.
Date: January 1, 1992
Creator: Singhal, S.C.
Partner: UNT Libraries Government Documents Department

Recent progress in zirconia-based fuel cells for power generation

Description: High temperature solid oxide fuel cells based upon yttria-stabilized zirconia electrolyte offer a clean, pollution-free technology to electrochemically generate electricity at high efficiencies. This paper reviews the designs, materials and fabrication processes used for such fuel cells. Most progress to date has been achieved with tubular geometry cells. A large number of tubular cells have been electrically tested, some to times up to 30,000 hours; these cells have shown excellent performance and performance stability. In addition, successively larger size electric generators utilizing these cells have been designed, built and operated since 1984. Two 25 kW power generation field test units have recently been fabricated; these units represent a major milestone in the commercialization of zirconia-based fuel cells for power generation.
Date: January 1, 1992
Creator: Singhal, S.C.
Partner: UNT Libraries Government Documents Department

Application of ionic and electronic conducting ceramics in solid oxide fuel cells

Description: Solid oxide fuel cells (SOFCs) offer a pollution-free technology to electrochemically generate electricity at high efficiencies. These fuel cells consist of an oxygen ion conducting electrolyte, electronic or mixed electronic and ionic conducting electrodes, and an electronic conducting interconnection. This paper reviews the ceramic materials used for the different cell components, and discusses the performance of cells fabricated using these materials. The paper also discusses the materials and processing studies that are underway to reduce the cell cost, and summarizes the recently built power generation systems that employed state-of-the-art SOFCs.
Date: December 1, 1997
Creator: Singhal, S.C.
Partner: UNT Libraries Government Documents Department

Recent progress in zirconia-based fuel cells for power generation

Description: High temperature solid oxide fuel cells based upon yttria-stabilized zirconia electrolyte offer a clean, pollution-free technology to electrochemically generate electricity at high efficiencies. This paper reviews the designs, materials and fabrication processes used for such fuel cells. Most progress to date has been achieved with tubular geometry cells. A large number of tubular cells have been electrically tested, some to times up to 30,000 hours; these cells have shown excellent performance and performance stability. In addition, successively larger size electric generators utilizing these cells have been designed, built and operated since 1984. Two 25 kW power generation field test units have recently been fabricated; these units represent a major milestone in the commercialization of zirconia-based fuel cells for power generation.
Date: December 1, 1992
Creator: Singhal, S. C.
Partner: UNT Libraries Government Documents Department

Zirconia-based fuel cells for power generation

Description: This paper reviews the design and operation of the high temperature solid oxide fuel cells based on yttria-stabilized zirconia electrolyte. The functional requirements of the various cell components are presented; and the materials and fabrication processes used for different cell components are described. Finally, the recent progress made toward commercialization of these cells for clean and efficient power generation is discussed.
Date: April 1, 1992
Creator: Singhal, S. C.
Partner: UNT Libraries Government Documents Department

1?10 kW Stationary Combined Heat and Power Systems Status and Technical Potential: Independent Review

Description: This independent review examines the status and technical potential of 1-10 kW stationary combined heat and power fuel cell systems and analyzes the achievability of the DOE cost, efficiency, and durability targets for 2012, 2015, and 2020.
Date: November 1, 2010
Creator: Maru, H. C.; Singhal, S. C.; Stone, C. & Wheeler, D.
Partner: UNT Libraries Government Documents Department

The effect of pressure on solid oxide fuel cell performance

Description: Current work in solid oxide fuel cells (SOFCs) is on cathode-supported, anode-supported, or electrolyte-supported cells. In electrode-supported cells, a thin film (5 to 30 microns) of an electrolyte (YSZ) is deposited on a relatively thick, porous electrode. In electrolyte-supported cells, the electrolyte thickness is typically greater than or equal 150 microns upon which thin electrodes are screen printed. Both types of SOFCs are being explored for hybrid applications, that is, in combination with a gas turbine, for which the exit gases from an SOFC generator must be at a high pressure (3 to 15 atm) for input into a gas turbine. It is necessary to examine the expected performance of an SOFC under a high pressure. Work at Westinghouse Ontario Hydro has shown that the performance improvement at high pressures is greater than that can be expected based on an increased Nernst potential alone. This increased performance can in part be attributed to a lower concentration polarization. The objective of this work was to conduct a preliminary analysis of the effect of pressure on the performance of both cathode-supported and electrolyte-supported cells. Flux equations for transport through porous electrodes are formulated and are solved in combination with those for electrochemical operation of an SOFC for cathode-supported and electrolyte-supported cells. The analysis shows that the overall cell performance increases significantly with increasing pressure in the case of cathode-supported cells due to a lowering of concentration polarization at high pressures. Similar effects (not presented here) are also observed on anode-supported cells. By contrast, only a modest improvement is observed in the case of electrolyte-supported cells, commensurate with the fact that in the latter, the ohmic contribution of the electrolyte is the most dominant one, which is not altered by pressure.
Date: December 1, 1997
Creator: Virkar, A.V.; Fung, K.Z. & Singhal, S.C.
Partner: UNT Libraries Government Documents Department

Recent progress in tubular solid oxide fuel cell technology

Description: The tubular design of solid oxide fuel cells (SOFCs) and the materials used therein have been validated by successful, continuous electrical testing over 69,000 h of early technology cells built on a calcia-stabilized zirconia porous support tube (PST). In the latest technology cells, the PST has been eliminated and replaced by a doped lanthanum manganite air electrode tube. These air electrode supported (AES) cells have shown a power density increase of about 33% with a significantly improved performance stability over the previously used PST type cells. These cells have also demonstrated the ability to thermally cycle over 100 times without any mechanical damage or performance loss. In addition, recent changes in processes used to fabricate these cells have resulted in significant cost reduction. This paper reviews the fabrication and performance of the state-of-the-art AES tubular cells. It also describes the materials and processing studies that are underway to further reduce the cell cost, and summarizes the recently built power generation systems that employed state-of-the-art AES cells.
Date: December 31, 1997
Creator: Singhal, S.C.
Partner: UNT Libraries Government Documents Department