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Sample records for planar sofc design

  1. Progress in the planar CPn SOFC system design verification

    Energy Technology Data Exchange (ETDEWEB)

    Elangovan, S.; Hartvigsen, J.; Khandkar, A. [SOFCo, Salt Lake City, UT (United States)

    1996-04-01

    SOFCo is developing a high efficiency, modular and scaleable planar SOFC module termed the CPn design. This design has been verified in a 1.4 kW module test operated directly on pipeline natural gas. The design features multistage oxidation of fuel wherein the fuel is consumed incrementally over several stages. High efficiency is achieved by uniform current density distribution per stage, which lowers the stack resistance. Additional benefits include thermal regulation and compactness. Test results from stack modules operating in pipeline natural gas are presented.

  2. Development of Osaka gas type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Iha, M.; Shiratori, A.; Chikagawa, O. [Murata Mfg. Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    Osaka Gas Co. has been developing a planar type SOFC (OG type SOFC) which has a suitable structure for stacking. Murata Mfg. Co. has begun to develop the OG type SOFC stack through joint program since 1993. Figure 1 shows OG type cell structure. Because each cell is sustained by cell holders acting air manifold, the load of upper cell is not put on the lower cells. Single cell is composed of 3-layered membrane and LaCrO{sub 3} separator. 5 single cells are mounted on the cell holder, connected with Ni felt electrically, and bonded by glassy material sealant. We call the 5-cell stack a unit. Stacking 13 units, we succeeded 870 W generation in 1993. But the power density was low, 0.11 Wcm{sup -2} because of crack in the electrolyte and gas leakage at some cells.

  3. Final Report, Validation of Novel Planar Cell Design for MW-Scale SOFC Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Swartz, Dr Scott L.; Thrun, Dr Lora B.; Arkenberg, Mr Gene B.; Chenault, Ms Kellie M.

    2012-01-03

    This report describes the work completed by NexTech Materials, Ltd. during a three-year project to validate an electrolyte-supported planar solid oxide fuel cell design, termed the FlexCell, for coal-based, megawatt-scale power generation systems. This project was focused on the fabrication and testing of electrolyte-supported FlexCells with yttria-stabilized zirconia (YSZ) as the electrolyte material. YSZ based FlexCells were made with sizes ranging from 100 to 500 cm2. Single-cell testing was performed to confirm high electrochemical performance, both with diluted hydrogen and simulated coal gas as fuels. Finite element analysis modeling was performed at The Ohio State University was performed to establish FlexCell architectures with optimum mechanical robustness. A manufacturing cost analysis was completed, which confirmed that manufacturing costs of less than $50/kW are achievable at high volumes (500 MW/year).

  4. Validation of Novel Planar Cell Design for MW-Scale SOFC Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Scott Swartz; Lora Thrun; Gene Arkenberg; Kellie Chenault

    2011-09-30

    This report describes the work completed by NexTech Materials, Ltd. during a three-year project to validate an electrolyte-supported planar solid oxide fuel cell design, termed the FlexCell, for coal-based, megawatt-scale power generation systems. This project was focused on the fabrication and testing of electrolyte-supported FlexCells with yttria-stabilized zirconia (YSZ) as the electrolyte material. YSZ based FlexCells were made with sizes ranging from 100 to 500 cm{sup 2}. Single-cell testing was performed to confirm high electrochemical performance, both with diluted hydrogen and simulated coal gas as fuels. Finite element analysis modeling was performed at The Ohio State University was performed to establish FlexCell architectures with optimum mechanical robustness. A manufacturing cost analysis was completed, which confirmed that manufacturing costs of less than $50/kW are achievable at high volumes (500 MW/year). DISCLAIMER

  5. Gradient composite metal-ceramic foam as supportive component for planar SOFCs and MIEC membranes

    International Nuclear Information System (INIS)

    Smorygo, Oleg; Mikutski, Vitali; Marukovich, Alexander; Sadykov, Vladislav; Usoltsev, Vladimir; Mezentseva, Natalia; Borodinecs, Anatolijs; Bobrenok, Oleg

    2011-01-01

    A novel approach to the design of planar gradient porous supports for the thin-film SOFCs and MIEC membranes is described. The support's thermal expansion is controlled by the creation of a two-component composite metal-ceramic foam structure. Thin MIEC membranes and SOFCs were prepared on the composite supports by the layerwise deposition of composite functional layers including complex fluorites and perovskites. Lab-scale studies demonstrated promising performance of both MIEC membrane and SOFC.

  6. Gradient composite metal-ceramic foam as supportive component for planar SOFCs and MIEC membranes

    Science.gov (United States)

    Smorygo, Oleg; Mikutski, Vitali; Marukovich, Alexander; Sadykov, Vladislav; Usoltsev, Vladimir; Mezentseva, Natalia; Borodinecs, Anatolijs; Bobrenok, Oleg

    2011-06-01

    A novel approach to the design of planar gradient porous supports for the thin-film SOFCs and MIEC membranes is described. The support's thermal expansion is controlled by the creation of a two-component composite metal-ceramic foam structure. Thin MIEC membranes and SOFCs were prepared on the composite supports by the layerwise deposition of composite functional layers including complex fluorites and perovskites. Lab-scale studies demonstrated promising performance of both MIEC membrane and SOFC.

  7. Development of cofired type planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Taira, Hiroaki; Sakamoto, Sadaaki; Zhou, Hua-Bing [Murata Manufacturing Co., Ltd., Shiga (Japan)] [and others

    1996-12-31

    We have developed fabrication process for planar SOFC fabricated with cofired anode/electrolyte/cathode multilayers and interconnects. By cofiring technique for the multilayers, we expect to reduce the thickness of the electrolyte layers, resulting in decrease of innerimpedance, and achieve low production cost. On the other hand, the cofiring technique requires that the sintering temperature, the shrinkage profiles and the thermal expansion characteristics of all component materials should be compatible with the other. It is, therefore, difficult to cofire the multilayers with large area. Using the multilayers with surface area of 150cm{sup 2}, we fabricated the multiple cell stacks. The maximum power of 5x4 multiple cell stack (5 planes of cells in series, 4 cells in parallel in each planes 484cm{sup 2} effective electrode area of each cell planes) was 601W (0.25Wcm{sup -2}, Uf=40%). However, the terminal voltage of the multiple cell stack decreased by the cause of cell cracking, gas leakage and degradation of cofired multilayers. This paper presents the improvements of cofired multilayers, and the performance of multiple cell stacks with the improved multilayers.

  8. Thermal stress analysis of a planar SOFC stack

    Science.gov (United States)

    Lin, Chih-Kuang; Chen, Tsung-Ting; Chyou, Yau-Pin; Chiang, Lieh-Kwang

    The aim of this study is, by using finite element analysis (FEA), to characterize the thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack during various stages. The temperature profiles generated by an integrated thermo-electrochemical model were applied to calculate the thermal stress distributions in a multiple-cell SOFC stack by using a three-dimensional (3D) FEA model. The constructed 3D FEA model consists of the complete components used in a practical SOFC stack, including positive electrode-electrolyte-negative electrode (PEN) assembly, interconnect, nickel mesh, and gas-tight glass-ceramic seals. Incorporation of the glass-ceramic sealant, which was never considered in previous studies, into the 3D FEA model would produce more realistic results in thermal stress analysis and enhance the reliability of predicting potential failure locations in an SOFC stack. The effects of stack support condition, viscous behavior of the glass-ceramic sealant, temperature gradient, and thermal expansion mismatch between components were characterized. Modeling results indicated that a change in the support condition at the bottom frame of the SOFC stack would not cause significant changes in thermal stress distribution. Thermal stress distribution did not differ significantly in each unit cell of the multiple-cell stack due to a comparable in-plane temperature profile. By considering the viscous characteristics of the glass-ceramic sealant at temperatures above the glass-transition temperature, relaxation of thermal stresses in the PEN was predicted. The thermal expansion behavior of the metallic interconnect/frame had a greater influence on the thermal stress distribution in the PEN than did that of the glass-ceramic sealant due to the domination of interconnect/frame in the volume of a planar SOFC assembly.

  9. Development status of planar SOFCs at Sanyo

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Yasuo; Akiyama, Yukinori; Yasuo, Takashi [SANYO Electric Co., Ltd., Osaka (Japan)] [and others

    1996-12-31

    A 2 kW class combined cell stacked module (182 cm{sup 2} X 4X 17) was examined. An output power of 2.47 kW and output power density of 0.20 W/cm{sup 2} were obtained at the current density of 0.3 A/cm{sup 2}. The temperature uniformity is an important factor to develop large scale SOFC modules. Therefore, in this 2 kW class module, one cell was divided into four smaller unit cells to decrease temperature difference across these cells. Moreover, an internal heat-exchanging duct was arranged to spend the surplus heat effectively in the middle of the module. As for the basic research, the followings were investigated to improve thermal cycle characteristics. One was to adopt a silica/alumina-based sealing, material in order to absorb the thermal expansion difference between the electrolyte and the separator. Deterioration was quite small after 12 thermal cycles with a 150 by 150 mm single cell. The other was to use a heat-resisting ferritic alloy as a separator in a 50 by 50 mm single cell in order to decrease the thermal expansion coefficient of the separator. High performance was obtained for 2000 hours at 900{degrees}C in an endurance test and deterioration was quite small after a thermal cycle.

  10. Study on durability for thermal cycle of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Motoo; Nakata, Kei-ichi; Wakayama, Sin-ichi [Tonen Corp., Saitama (Japan)] [and others

    1996-12-31

    TONEN CORPORATION has developed planar type SOFC since 1986. We demonstrated the output of 1.3 kW in 1991 and 5.1 kW in 1995. Simultaneously we have studied how to raise electric efficiency and reliability utilizing hydrogen and propane as fuel. Durability for thermal cycle is one of the most important problems of planar SOFC to make it more practical. The planar type SOFC is made up of separator, zirconia electrolyte and glass sealant. The thermal expansion of these components are expected to be the same value, however, they still possess small differences. In this situation, a thermal cycle causes a thermal stress due to the difference of the cell components and is often followed by a rupture in cell components, therefore, the analysis of the thermal stress should give us much useful information. The thermal cycle process consists of a heating up and cooling down procedure. Zirconia electrolyte is not bonded to the separator under the condition of the initial heating up procedure, and glass sealant becomes soft or melts and glass seals spaces between the zirconia and separator. The glass sealant becomes harder with the cooling down procedure. Moreover, zirconia is tightly bonded with separator below a temperature which is defined as a constraint temperature and thermal stress also occurs. This indicates that the heating up process relaxes the thermal stress and the cooling down increases it. In this paper, we simulated dependence of the stress on the sealing configuration, thermal expansion of sealant and constraint temperature of sealant glass. Furthermore, we presented SOFC electrical properties after a thermal cycle.

  11. Realisation of an anode supported planar SOFC system

    Energy Technology Data Exchange (ETDEWEB)

    Buchkremer, H.P.; Stoever, D. [Institut fuer Werkstoffe der Energietechnik, Juelich (Germany); Diekmann, U. [Zentralabteilung Technologie, Juelich (Germany)] [and others

    1996-12-31

    Lowering the operating temperature of S0FCs to below 800{degrees}C potentially lowers production costs of a SOFC system because of a less expensive periphery and is able to guarantee sufficient life time of the stack. One way of achieving lower operating temperatures is the development of new high conductive electrolyte materials. The other way, still based on state-of-the-art material, i.e. yttria-stabilized zirconia (YSZ) electrolyte, is the development of a thin film electrolyte concept. In the Forschungszentrum Julich a program was started to produce a supported planar SOFC with an YSZ electrolyte thickness between 10 to 20 put. One of the electrodes, i.e. the anode, was used as support, in order not to increase the number of components in the SOFC. The high electronic conductivity of the anode-cermet allows the use of relatively thick layers without increasing the cell resistance. An additional advantage of the supported planar concept is the possibility to produce single cells larger than 10 x 10 cm x cm, that is with an effective electrode cross area of several hundred cm{sup 2}.

  12. Development of planar SOE/SOFC reversible cell

    International Nuclear Information System (INIS)

    Kusunoki, A.; Matsubara, H.; Kikuoka, Y.; Yanagi, C.; Kugimiya, K.; Yoshino, M.; Tokura, M.; Watanabe, K.; Ueda, S.; Sumi, M.; Miyamoto, H.; Tokunaga, S.

    1993-01-01

    A new energy storage system using SOE/SOFC (solid oxide electrolysis-solid oxide fuel cells) reversible cells is presented, where a unit cell works as a fuel cell during a period of high electric power demand and alternately works as an electrolysis cell during a period of low power demand. A planar cell configuration is used which allows for a compact and low cost energy storage and load leveling system for power stations. Tests were performed to verify the reversibility of the planar cell, at 1000 deg C, with YSZ (Yttria stabilized zirconia) as the solid electrolyte, to improve the cell performance by reducing the overvoltage in electrolysis, and to obtain fundamental characteristics of a reversible cell. 3 figs

  13. A Zero-Dimensional Model of a 2nd Generation Planar SOFC Using Calibrated Parameters

    DEFF Research Database (Denmark)

    Petersen, Thomas Frank

    2006-01-01

    This paper presents a zero-dimensional mathematical model of a planar 2nd generation co-flow SOFC developed for simulation of power systems. The model accounts for the electrochemical oxidation of hydrogen as well as the methane reforming reaction and the water-gas shift reaction. An important part...... SOFC-based power systems....

  14. Electrically Conductive and Protective Coating for Planar SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Stevenson, Jeffry W.

    2017-12-04

    Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

  15. Technical development and economic valuation of new cooling methods for planar solid oxide fuel cells (SOFC)

    International Nuclear Information System (INIS)

    Thom, F.

    2002-02-01

    A great potential exists for the use of the solid oxide fuel cell technology based on the planar cell design concept. Besides its application as power provider there is a need to supply process heat in the temperature range of 200 to 1200 C for commercial and industrial decentralized facilities. The present study is concerned with the technical development and economic valuation of plant concepts of new fuel cell cooling methods. They can be considered as an alternative to the normal convective cell cooling with air. Besides experimental studies on the natural gas reforming with the SOFC special attention is paid to the process analysis of the power plant carried out with the simulating program PROII. The 200 kWe SOFC is linked with peripheral components such as prereformer, heat exchangers, compressors etc. Developed program subroutine serve to calculate the electrical power output of the fuel cell, the investment costs and the costs of electricity. The study shows clearly that a radiative cell cooling device on basis of an external arranged vaporizer has economic benefits in comparison with the normal air cooling. In this case the possibility is given to run the fuel cell with completely prereformed natural gas. When the internal methane reforming is carried out in excess of the electrochemical demand for hydrogen and carbon monoxide respectively a further cost reduction potential is given. The produced synthesis gas can be used in alternative to the production of power in a gas turbine to supply process steam in the temperature range of 200 to 1200 C. Sensitivity analyses show that a successive use of optimization potentials (e.g. anode structure and operating parameters of the SOFC) leads to a further reduction of the costs of electricity. In the best case the achieved costs of 12 to 13 Pf/kWh are in a range achieved by CHP plants based on engines. (orig.) [de

  16. Temperature and flow distribution in planar SOFC stacks

    Directory of Open Access Journals (Sweden)

    Monica Østenstad

    1995-07-01

    Full Text Available Simulation of a planar Solid Oxide Fuel Cell stack requires the solution of the mass balances of the chemical species, the energy balances, the charge balance and the channel flow equations in order to compute the species concentrations, the temperature distributions, the current density and the channel flows. The unit cell geometry can be taken into account by combining detailed modeling of a unit cell with a homogenized model of a whole stack. In this study the effect of the asymmetric temperature distribution on the channel flows in a conventional cross-flow design has been investigated. The bidirectional cross-flow design is introduced, for which we can show more directional temperature and flow distributions.

  17. LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Song, Rak-Hyun; Shin, Dong Ryul [Korea Institute of Energy Research, Taejon (Korea, Republic of); Dokiya, Masayuki [National Institute of Materials and Chemical Research, Ibaraki (Japan)

    1996-12-31

    In the planar SOFC, the interconnect materials plays two roles as an electrical connection and as a gas separation plate in a cell stack. The interconnect materials must be chemically stable in reducing and oxidizing environments, and have high electronic conductivity, high thermal conductivity, matching thermal expansion with an electrolyte, high mechanical strength, good fabricability, and gas tightness. Lanthanum chromite so far has been mainly used as interconnect materials in planar SOFC. However, the ceramic materials are very weak in mechanical strength and have poor machining property as compared with metal. Also the metallic materials have high electronic conductivity and high thermal conductivity. Recently some researchers have studied metallic interconnects such as Al{sub 2}O{sub 3}/Inconel 600 cermet, Ni-20Cr coated with (LaSr)CoO{sub 3}, and Y{sub 2}O{sub 3-} or La{sub 2}O{sub 3}-dispersed Cr alloy. These alloys have still some problems because Ni-based alloys have high thermal expansion, the added Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and La{sub 2}O{sub 3} to metals have no electronic conductivity, and the oxide formed on the surface of Cr alloy has high volatility. To solve these problems, in this study, LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC was investigated. The LaCrO{sub 3}-dispersed Cr can be one candidate of metallic interconnect because LaCrO{sub 3} possesses electronic conductivity and Cr metal has relatively low thermal expansion. The content of 25 vol.% LaCrO{sub 3} Was selected on the basis of a theoretically calculated thermal expansion. The thermal expansion, electrical and oxidation properties were examined and the results were discussed as related to SOFC requirements.

  18. Hydrogen consumption and power density in a co-flow planar SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Ben Moussa, Hocine; Zitouni, Bariza [Laboratoire d' etude des systemes energetiques industriels (LESEI), Universite de Batna, Batna (Algeria); Oulmi, Kafia [Laboratoire de chimie et de chimie de l' environnement, Universite de Batna, Batna (Algeria); Mahmah, Bouziane; Belhamel, Maiouf [CDER, BP. 62 Route de l' Observatoire. Bouzareah. Alger (Algeria); Mandin, Philippe [Centre de Developpement des Energies Renouvelables (CDER), LECA, UMR 7575 CNRS-ENSCP Paris 6 (France)

    2009-06-15

    In the present work, power density and hydrogen consumption in a co-flow planar solid oxide fuel cell (SOFC) are studied according to the inlet functional parameters; such as the operational temperature, the operational pressure, the flow rates and the mass fractions of the species. Furthermore, the effect of the cell size is investigated. The results of a zero and a one-dimensional numerical electro-dynamic model predict the remaining quantity of the fed hydrogen at the output of the anode flow channel. The remaining hydrogen quantities and the SOFC's power density obtained are discussed as a function of the inlet functional parameters, the geometrical configuration of the cell and several operating cell voltages values. (author)

  19. Production and Reliability Oriented SOFC Cell and Stack Design

    DEFF Research Database (Denmark)

    Hauth, Martin; Lawlor, Vincent; Cartellieri, Peter

    2017-01-01

    The paper presents an innovative development methodology for a production and reliability oriented SOFC cell and stack design aiming at improving the stacks robustness, manufacturability, efficiency and cost. Multi-physics models allowed a probabilistic approach to consider statistical variations...... in production, material and operating parameters for the optimization phase. A methodology for 3D description of spatial distribution of material properties based on a random field models was developed and validated by experiments. Homogenized material models on multiple levels of the SOFC stack were...... and output parameters and to perform a sensitivity analysis were developed and implemented. The capabilities of the methodology is illustrated on two practical cases....

  20. Design of special planar linkages

    CERN Document Server

    Zhao, Jing-Shan; Ma, Ning; Chu, Fulei

    2013-01-01

    Planar linkages play a very important role in mechanical engineering. As the simplest closed chain mechanisms, planar four-bar linkages are widely used in mechanical engineering, civil engineering and aerospace engineering.Design of Special Planar Linkages proposes a uniform design theory for planar four-bar linkages. The merit of the method proposed in this book is that it allows engineers to directly obtain accurate results when there are such solutions for the specified n precise positions; otherwise, the best approximate solutions will be found. This book discusses the kinematics and reach

  1. Performance simulation of planar SOFC using mixed hydrogen and carbon monoxide gases as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Inui, Y. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)]. E-mail: inui@eee.tut.ac.jp; Urata, A. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Ito, N. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Nakajima, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Tanaka, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)

    2006-08-15

    The authors investigate in detail the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC through numerical simulations for a single cell plate of the co-flow type planar cell. It is made clear that the cell performance is almost the same and excellent, independent of the mixing ratio of hydrogen and carbon monoxide under the nominal operating condition. The electromotive force of the hydrogen rich fuel gas is a little higher than that of the carbon monoxide rich fuel gas. The internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high. Since the value of the single cell voltage is determined by the balance of these two phenomena, the lowering of the electromotive force is dominant and the single cell voltage of the hydrogen rich fuel gas is higher when the inlet gas temperature is high, whereas the voltage drop reduction is dominant and the single cell voltage of the carbon monoxide rich fuel gas is higher when the temperature is low. The effect of the additional gases of water vapor and carbon dioxide is restricted to the single cell voltage shift, and the qualitative dependence of the single cell voltage on the inlet gas temperature is determined by the mixing ratio of hydrogen and carbon monoxide.

  2. Performance simulation of planar SOFC using mixed hydrogen and carbon monoxide gases as fuel

    International Nuclear Information System (INIS)

    Inui, Y.; Urata, A.; Ito, N.; Nakajima, T.; Tanaka, T.

    2006-01-01

    The authors investigate in detail the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC through numerical simulations for a single cell plate of the co-flow type planar cell. It is made clear that the cell performance is almost the same and excellent, independent of the mixing ratio of hydrogen and carbon monoxide under the nominal operating condition. The electromotive force of the hydrogen rich fuel gas is a little higher than that of the carbon monoxide rich fuel gas. The internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high. Since the value of the single cell voltage is determined by the balance of these two phenomena, the lowering of the electromotive force is dominant and the single cell voltage of the hydrogen rich fuel gas is higher when the inlet gas temperature is high, whereas the voltage drop reduction is dominant and the single cell voltage of the carbon monoxide rich fuel gas is higher when the temperature is low. The effect of the additional gases of water vapor and carbon dioxide is restricted to the single cell voltage shift, and the qualitative dependence of the single cell voltage on the inlet gas temperature is determined by the mixing ratio of hydrogen and carbon monoxide

  3. Market orientated design studies for SOFC based systems

    Energy Technology Data Exchange (ETDEWEB)

    Nietsch, T.; Clark, J.

    1999-07-01

    This report examines the development status of Solid Oxide Fuel Cell (SOFC) technology, assesses its commercial potential for heat and power generation in the UK and identifies key development areas for both the SOFC stack and associated system components. A range of Distributed Generation (DG) and Combined Heat and Power (CHP) applications were considered in arriving at these recommendations. The project commenced with initial surveys of leading SOFC technology companies and centres world-wide. These surveys were conducted in parallel with consultations with key operator organisations in the UK which enabled the requirements of these organisations within the UK Energy Supply Industry to be identified. As a result of the initial survey, over 30 fuel cell based power plants, of size ranging from 1 kW{sub e} to 20 MW{sub e} for both DG and CHP applications, were identified. Outline designs of these applications were then set up and simulated. These candidate systems were then assessed against each other in terms of efficiency, cost of electricity, specific costs, technical risk and market potential for the UK industry. The final ranking obtained was then confirmed with the key operator organisations. On the basis of the ranking process noted above, nine SOFC based power generation/CHP applications were chosen for more detailed investigation in terms of their potential in both UK and overseas markets. Detailed simulations were conducted for each application to allow study of: the influence of efficiency on the economics of the different plants/stacks; the combination of stack and Balance of Plant (BoP) costs; and the cost and availability of key balance of plant devices. These systems were then again assessed in terms of the criteria noted for the outline stage. Finally key development areas for both SOFC stacks and associated Balance of Plant devices were identified. (author)

  4. Development and fabrication of a new concept planar-tubular solid oxide fuel cell (PT-SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.; Chen, F. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Ding, D. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Gao, J. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China)

    2011-06-15

    The paper reports a new concept of planar-tubular solid oxide fuel cell (PT-SOFC). Emphasis is on the fabrication of the required complex configuration of Ni-yttria-stabilised zirconia (YSZ) porous anode support by tert-butyl alcohol (TBA) based gelcasting, particularly the effects of solid loading, amounts of monomers and dispersant on the rheological behaviour of suspension, the shrinkage of a wet gelcast green body upon drying, and the properties of final sample after sintering at 1350 C and reduction from NiO-YSZ to Ni-YSZ. The results show that the gelcasting is a powerful method for preparation of the required complex configuration anode support. The anode support resulted from an optimised suspension with the solid loading of 25 vol% has uniform microstructure with 37% porosity, bending strength of 44 MPa and conductivity of 300 S cm{sup -} {sup 1} at 700 C, meeting the requirements for an anode support of SOFC. Based on the as-prepared anode support, PT-SOFC single cell of Ni-YSZ/YSZ/LSCF has been fabricated by slurry coating and co-sintering technique. The cell peak power density reaches 63, 106 and 141 mW cm {sup -} {sup 2} at 700, 750 and 800 C, respectively, using hydrogen as fuel and ambient air as oxidant. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. CFD analysis of a symmetrical planar SOFC with heterogeneous electrode properties

    International Nuclear Information System (INIS)

    Shi Junxiang; Xue Xingjian

    2010-01-01

    A comprehensive 2-D CFD model is developed to investigate bi-electrode supported cell (BSC) performance. The model takes into account the coupled complex transport phenomena of mass/heat transfer, charge (electron/ion) transport, and electrochemical reactions. The uniqueness of this modeling work is that heterogeneous electrode properties are taken into account, which includes not only linear functionally graded porosity distribution but also various nonlinear distributions in a general sense according to porous electrode features in BSC design. Extensive numerical analysis is performed to elucidate various heterogeneous porous electrode property effects on cell performance. Results indicate that cell performance is strongly dependent on porous microstructure distributions of electrodes. Among the various porosity distributions, inverse parabolic porosity distribution shows promising effects on cell performance. For a given porosity distribution of electrodes, cell performance is also dependent on operating conditions, typically fuel/gas pressure losses across the electrodes. The mathematical model developed in this paper can be utilized for high performance BSC SOFC design and optimization.

  6. Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

    Science.gov (United States)

    Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

    2017-02-01

    Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

  7. Barium boron silicate glass-ceramic for use as sealant in planar SOFC

    International Nuclear Information System (INIS)

    Silva, M.J.; Castanho, S.R.H. Mello; Reis, S.T.

    2012-01-01

    Glass-ceramic seals play an important role in the performance of the solid oxide fuel cell (SOFC). In this work glass-ceramic seals are discussed from the point of view of the thermal behavior of the glass and the electrochemical parameters obtained from polarization curves such as corrosion current densities (i corr ), and corrosion potential (E corr ). A seal material must have a combination of thermal-mechanical and electrochemical properties in order to seal cell components and stacks and prevent side reactions. It must be stable in oxidizing and reducing atmospheres and withstand thermal cycles between room temperature and the cell operating temperature (800 to 900°C). Glass-ceramics in the system BaO- B 2 O 3 -Al 2 O 3 -SiO 2 were investigated and compared from the point of view of sealing ability. Dilatometric analysis, thermal stability against crystallization, microstructure and electrochemical durability are discussed. (author)

  8. Design, Operation and Control Modelling of SOFC/GT Hybrid Systems

    OpenAIRE

    Stiller, Christoph

    2006-01-01

    This thesis focuses on modelling-based design, operation and control of solid oxide fuel cell (SOFC) and gas turbine (GT) hybrid systems. Fuel cells are a promising approach to high-efficiency power generation, as they directly convert chemical energy to electric work. High-temperature fuel cells such as the SOFC can be integrated in gas turbine processes, which further increases the electrical efficiency to values up to 70%. However, there are a number of obstacles for safe operation of such...

  9. Manufacturing of cells and stacks for SOFC development, test and demonstration projects and SOFC hotbox design development

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    The purpose of this project is to support the continued SOFC development through manufacturing process optimization and manufacturing of SOFC cells and stacks. These cells and stacks will serve as a necessary base for the development activities and for the establishment of a number of test and demonstration activities. The manufacture will also help provide operating experience and reduce manufacturing cost. Another main focus of the manufacturing is to assure technical improvements and reliability. It is imperative to the eventual success of the technology that test and demonstration is carried out in the pre-market conditions that will exist for the next years in the three market segments targeted by TOFC (Distributed generation, micro CHP and APU incl. marine APU). Finally, the project also includes development activities focusing on the stack-system interface (hotbox design development) and on dealing with transients and start up and shut down times, which is of particular importance for APU and micro CHP applications. Three topics are addressed:1) Cell manufacture, including production development, capacity lift and manuf. of cells for test and demonstration; 2) Stack manufacture and test, including a test facility, stack manuf. and test of stacks in a system at HCV; 3) Hotbox design development, including design, prototype construction and testing. The progress of this project is documented. Major achievements are successful manufacture of adequate amounts of cells and stacks according to the application. Furthermore significant over-performance in design, construction and test of a methanol based hotbox prototype as well as publication of this. (au)

  10. Cold start dynamics and temperature sliding observer design of an automotive SOFC APU

    Science.gov (United States)

    Lin, Po-Hsu; Hong, Che-Wun

    This paper presents a dynamic model for studying the cold start dynamics and observer design of an auxiliary power unit (APU) for automotive applications. The APU is embedded with a solid oxide fuel cell (SOFC) stack which is a quiet and pollutant-free electric generator; however, it suffers from slow start problem from ambient conditions. The SOFC APU system equips with an after-burner to accelerate the start-up transient in this research. The combustion chamber burns the residual fuel (and air) left from the SOFC to raise the exhaust temperature to preheat the SOFC stack through an energy recovery unit. Since thermal effect is the dominant factor that influences the SOFC transient and steady performance, a nonlinear real-time sliding observer for stack temperature was implemented into the system dynamics to monitor the temperature variation for future controller design. The simulation results show that a 100 W APU system in this research takes about 2 min (in theory) for start-up without considering the thermal limitation of the cell fracture.

  11. Design of a SOFC/GT/SCs hybrid power system to supply a rural isolated microgrid

    International Nuclear Information System (INIS)

    Camblong, Haritza; Baudoin, Sylvain; Vechiu, Ionel; Etxeberria, Aitor

    2016-01-01

    Highlights: • A novel SOFC/GT/SCs HPS is connected to a rural microgrid through a 3LNPC inverter. • An operating strategy that maintains the SOFC power at its rated value is defined. • A robust digital controller that damps current oscillations is designed. • The efficiency, power quality, lifetime, and robustness of the HPS are considered. • An experimental test on an original HPS emulator validates the proposed solutions. - Abstract: The aim of this research study has been to design a Hybrid Power System (HPS) which works with biogas and whose main components are a Solid Oxide Fuel Cell (SOFC), a Gas microTurbine (GT), and a module of SuperCapacities (SCs). The HPS is the only power source of a rural isolated microgrid. Its structure, operating strategy, and controller have been designed considering the following criteria: efficiency, power quality, SOFC lifetime and robustness in stability and performance. The HPS structure includes a unique power converter, a 3-Level Neutral Point Clamped (3LNPC) inverter that connects the HPS to the AC microgrid. Regarding the selected operating strategy, it consists in regulating the SOFC power output to its rated value. Thus, the SCs and the GT must respond to the power demand variations. On the other hand, a study of the HPS shows that its dynamic behavior is not linear. Therefore, a special attention is put on designing a robust HPS controller. The control model is identified and the robust digital controller is designed using the “Tracking and Regulation with Independent Objectives” method. Simulation and experimental results show how the proposed structure, operating strategy, and controller allow ensuring a good behavior of the HPS from the point of view of the abovementioned four criteria.

  12. Design, integration and demonstration of a 50 W JP8/kerosene fueled portable SOFC power generator

    Science.gov (United States)

    Cheekatamarla, Praveen K.; Finnerty, Caine M.; Robinson, Charles R.; Andrews, Stanley M.; Brodie, Jonathan A.; Lu, Y.; DeWald, Paul G.

    A man-portable solid oxide fuel cell (SOFC) system integrated with desulfurized JP8 partial oxidation (POX) reformer was demonstrated to supply a continuous power output of 50 W. This paper discusses some of the design paths chosen and challenges faced during the thermal integration of the stack and reformer in aiding the system startup and shutdown along with balance of plant and power management solutions. The package design, system capabilities, and test results of the prototype unit are presented.

  13. Impact of cell design and operating conditions on the performances of SOFC fuelled with methane

    Science.gov (United States)

    Laurencin, J.; Lefebvre-Joud, F.; Delette, G.

    An in-house-model has been developed to study the thermal and electrochemical behaviour of a planar SOFC fed directly with methane and incorporated in a boiler. The usual Ni-YSZ cermet has been considered for the anode material. It has been found that methane reforming into hydrogen occurs only at the cell inlet in a limited depth within the anode. A sensitivity analysis has allowed establishing that anode thicknesses higher than ∼400-500 μm are required to achieve both the optimal methane conversion and electrochemical performances. The direct internal reforming (DIR) mechanisms and the impact of operating conditions on temperature gradients and SOFC electrical efficiencies have been investigated considering the anode supported cell configuration. It has been shown that the temperature gradient is minimised in the autothermal mode of cell operation. Thermal equilibrium in the stack has been found to be strongly dependent on radiative heat losses with the stack envelope. Electrochemical performance and cell temperature maps have been established as a function of methane flow rates and cell voltages.

  14. Full load synthesis/design optimization of a hybrid SOFC-GT power plant

    International Nuclear Information System (INIS)

    Calise, F.; Dentice d' Accadia, M.; Vanoli, L.; Spakovsky, Michael R. von

    2007-01-01

    In this paper, the optimization of a hybrid solid oxide fuel cell-gas turbine (SOFC-GT) power plant is presented. The plant layout is based on an internal reforming SOFC stack; it also consists of a radial gas turbine, centrifugal compressors and plate-fin heat exchangers. In the first part of the paper, the bulk-flow model used to simulate the plant is presented. In the second part, a thermoeconomic model is developed by introducing capital cost functions. The whole plant is first simulated for a fixed configuration of the most important synthesis/design (S/D) parameters in order to establish a reference design configuration. Next a S/D optimization of the plant is carried out using a traditional single-level approach, based on a genetic algorithm. The optimization determined a set of S/D decision variable values with a capital cost significantly lower than that of the reference design, even though the net electrical efficiency for the optimal configuration was very close to that of the initial one. Furthermore, the optimization procedure dramatically reduced the SOFC active area and the compact heat exchanger areas

  15. The Design of Connection Solid Oxide Fuel Cell (SOFC) Integrated Grid with Three-Phase Inverter

    Science.gov (United States)

    Darjat; Sulistyo; Triwiyatno, Aris; Thalib, Humaid

    2018-03-01

    Fuel cell technology is a relatively new energy-saving technology that has the potential to replace conventional energy technologies. Among the different types of generation technologies, fuel cells is the generation technologies considered as a potential source of power generation because it is flexible and can be placed anywhere based distribution system. Modeling of SOFC is done by using Nernst equation. The output power of the fuel cell can be controlled by controlling the flow rate of the fuels used in the process. Three-phase PWM inverter is used to get the form of three-phase voltage which same with the grid. In this paper, the planning and design of the SOFC are connected to the grid.

  16. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    OpenAIRE

    Mihails Kusnezoff; Nikolai Trofimenko; Martin Müller; Alexander Michaelis

    2016-01-01

    The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC) is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type i...

  17. Status of SOFCo SOFC technology development

    Energy Technology Data Exchange (ETDEWEB)

    Privette, R.; Perna, M.A.; Kneidel, K. [SOFCo, Alliance, OH (United States)] [and others

    1996-12-31

    SOFCo, a Babcock & Wilcox/Ceramatec Research & Development Limited Partnership, is a collaborative research and development venture to develop technologies related to planar, solid-oxide fuel cells (SOFCs). SOFCo has successfully demonstrated a kW-class, solid-oxide fuel cell module operating on pipeline natural gas. The SOFC system design integrates the air preheater and the fuel processor with the fuel cell stacks into a compact test unit; this is the platform for multi-kW modules. The cells, made of tape-cast zirconia electrolyte and conventional electrode materials, exhibit excel lent stability in single-cell tests approaching 40,000 hours of operation. Stack tests using 10-cm and 15-cm cells with ceramic interconnects also show good performance and stability in tests for many thousands of hours.

  18. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells

    Directory of Open Access Journals (Sweden)

    Mihails Kusnezoff

    2016-11-01

    Full Text Available The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  19. Influence of Electrode Design and Contacting Layers on Performance of Electrolyte Supported SOFC/SOEC Single Cells.

    Science.gov (United States)

    Kusnezoff, Mihails; Trofimenko, Nikolai; Müller, Martin; Michaelis, Alexander

    2016-11-08

    The solid oxide cell is a basis for highly efficient and reversible electrochemical energy conversion. A single cell based on a planar electrolyte substrate as support (ESC) is often utilized for SOFC/SOEC stack manufacturing and fulfills necessary requirements for application in small, medium and large scale fuel cell and electrolysis systems. Thickness of the electrolyte substrate, and its ionic conductivity limits the power density of the ESC. To improve the performance of this cell type in SOFC/SOEC mode, alternative fuel electrodes, on the basis of Ni/CGO as well as electrolytes with reduced thickness, have been applied. Furthermore, different interlayers on the air side have been tested to avoid the electrode delamination and to reduce the cell degradation in electrolysis mode. Finally, the influence of the contacting layer on cell performance, especially for cells with an ultrathin electrolyte and thin electrode layers, has been investigated. It has been found that Ni/CGO outperform traditional Ni/8YSZ electrodes and the introduction of a ScSZ interlayer substantially reduces the degradation rate of ESC in electrolysis mode. Furthermore, it was demonstrated that, for thin electrodes, the application of contacting layers with good conductivity and adhesion to current collectors improves performance significantly.

  20. Mechanical characterisation at nanometric scale of a new design of SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Roa, J.J.; Morales, M.; Segarra, M. [Department of Materials Science and Metallurgical Engineering, University of Barcelona, 08028 Barcelona (Spain); Ruiz-Morales, J.C.; Nunez, P. [Department of Inorganic Chemistry, University of La Laguna, 38200 Tenerife (Spain); Canales-Vazquez, J. [Renewable Energies Research Institute, Albacete Science and Technology Park, University of Castilla la Mancha, 02006 Albacete (Spain); G Capdevila, X. [Centre of Design and Optimisation of Processes and Materials, Parc Cientific of Barcelona, 08028 Barcelona (Spain)

    2011-02-15

    The mechanical stability is an important parameter to gain knowledge in the potential applications of a novel design of electrolyte-supported SOFC, based on yttria-stabilised zirconia (YSZ) and NiO-YSZ composites, with cross-linked channels ({proportional_to}90 {mu}m of diameter). In this experimental work, the mechanical properties (hardness, H and Young's modulus, E) at different applied loads have been studied using the nanoindentation technique and the equivalent indenter method. On the other hand, the different fracture mechanisms have been determined using atomic force microscopy (AFM), observing the plastic behaviour that takes place during the indentation process. H value for YSZ is higher than that for NiO-YSZ, while E values for YSZ and NiO-YSZ are 260 {+-} 15 and 205 {+-} 20 GPa, respectively. Only YSZ samples present several radial cracks at the corners nucleated by sharp indentation, thus indicating that H values have been underestimated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Current progress in the design and setup of a SOFC/GT hybrid power plant

    OpenAIRE

    Schnegelberger, Christian; Henke, Moritz; Tomberg, Marius; Heddrich, Marc; Friedrich, K. Andreas

    2017-01-01

    The German Aerospace Center (DLR) is setting up a hybrid power plant with 30 kW electrical power output. It consists of a SOFC and a micro gas turbine (MGT). The hybrid power plant can reach electrical system efficiencies greater than 60 % throughout a wide operating range. Due to the SOFC’s high operation temperature and incomplete fuel utilisation, the exhaust gas will always contain usable energy. The MGT will use this energy to provide compressed and preheated air for the SOFC and ge...

  2. Manufacturing of planar ceramic interconnects

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, B.L.; Coffey, G.W.; Meinhardt, K.D.; Armstrong, T.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-12-31

    The fabrication of ceramic interconnects for solid oxide fuel cells (SOFC) and separator plates for electrochemical separation devices has been a perennial challenge facing developers. Electrochemical vapor deposition (EVD), plasma spraying, pressing, tape casting and tape calendering are processes that are typically utilized to fabricate separator plates or interconnects for the various SOFC designs and electrochemical separation devices. For sake of brevity and the selection of a planar fuel cell or gas separation device design, pressing will be the only fabrication technique discussed here. This paper reports on the effect of the characteristics of two doped lanthanum manganite powders used in the initial studies as a planar porous separator for a fuel cell cathode and as a dense interconnect for an oxygen generator.

  3. Simulation of the steady-state behaviour of a new design of a single planar Solid Oxide Fuel Cell

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2016-03-01

    Full Text Available The aim of the work was to develop a mathematical model for computing the steady-state voltage – current characteristics of a planar Solid Oxide Fuel Cell and to determine the performance of a new SOFC design. The design involves cross-flow bipolar plates. Each of the bipolar plates has an air channel system on one side and a fuel channel system on the other side. The proposed model was developed using the ANSYS-Fluent commercial Computational Fluid Dynamics (CFD software supported by additional Fuel Cell module. The results confirm that the model can well simulate the diagonal current path. The effects of temperature and gas flow through the channels and a Membrane Electrode Assembly (MEA structure were taken into account. It was shown that a significant increase of the MEA temperature at high current density can lead to hot spots formation and hence electrode damage.

  4. Analysis and design of efficient planar leaky-wave antennas

    NARCIS (Netherlands)

    Ettore, M.

    2008-01-01

    This thesis deals with the effective design of planar leaky-wave antennas. The work describes a methodology based on the polar expansion of Green's function representations to address very different geometrical configurations which might appear to have little in common. In fact leaky waves with

  5. Frontiers in Planar Lightwave Circuit Technology Design, Simulation, and Fabrication

    CERN Document Server

    Janz, Siegfried; Tanev, Stoyan

    2005-01-01

    This book is the result of the NATO Advanced Research Workshop on Frontiers in Planar Lightwave Circuit Technology, which took place in Ottawa, Canada from September 21-25, 2004. Many of the world’s leading experts in integrated photonic design, theory and experiment were invited to give lectures in their fields of expertise, and participate in discussions on current research and applications, as well as the new directions planar lightwave circuit technology is evolving towards. The sum of their contributions to this book constitutes an excellent record of many key issues and scientific problems in planar lightwave circuit research at the time of writing. In this volume the reader will find detailed overviews of experimental and theoretical work in high index contrast waveguide systems, micro-optical resonators, nonlinear optics, and advanced optical simulation methods, as well as articles describing emerging applications of integrated optics for medical and biological applications.

  6. Pressurisation of IP-SOFC technology for second generation hybrid application

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.

    2005-07-01

    The Integrated Planar Solid Oxide Fuel Cell (IP-SOFC) technology developed by Rolls-Royce plc is a hybrid fuel cell technology considered highly suitable for the distributed power generation market. This report presents the results of a project to examine the technical viability of the IP-SOFC technology and some of the associated hybrid system component technologies under pressurised conditions and to investigate the validity of the predicted pressurisation phenomena. The work included: identification of critical material specifications, construction processes, control parameters, etc; the design and commissioning of two pressurised IP-SOFC test rigs at Rolls Royce in Derby; testing two multi-bundle strips at high temperature and atmospheric pressure; testing an active IP-SOFC bundle at high temperature and pressure; testing an experimental steam reforming unit at high temperature and pressure; testing a novel low pressure drop, off-gas combustor concept under atmospheric and pressurised conditions; design studies to identify key parameters affecting the successful integration and packaging of the fuel cell stack with certain associated hybrid components; and designing a hybrid system experimental verification rig. Significant progress was made in addressing the development challenges associated with the IP-SOFC of leakage, performance, durability, yield and geometry, the reaction rate of steam reforming and emissions from the off-gas combustor. Recommendations for future work are made.

  7. SOFC: Processes and characteristics of ageing behaviour

    International Nuclear Information System (INIS)

    Gerganov, T.; Grigorov, S.; Kozhukharov, S.

    2005-01-01

    The high-temperature solid oxide fuel cell (SOFC) is convenient for the environmental friendly and efficient conversion of chemical into electric energy. During the last decade the development of planar SOFC stacks with metallic interconnects has made considerable progress in both size and power density. The improvement of durability in long-term operation of planar SOFC components is one of the main fields for stationary applications. Ageing of stacks can be caused by various processes, e.g. corrosion of metallic plates, degradation of ceramic parts and chemical interactions on electrodes/electrolyte or interconnect/electrode interface. Namely, these processes are object of the overview in the present work. The most important characteristics of ageing behavior are subjected to analysis and discussion, as well. Moreover a correlation between ageing process and single cell performance will be given

  8. Design of a novel 6-DOF planar maglev system

    International Nuclear Information System (INIS)

    Lai, Y.-C.; Yen, J.-Y.

    2006-01-01

    This paper describes a novel single-deck and six degree-of-freedom (DOF) planar maglev positioning system design. The proposed design uses an array of solenoids to levitate and to hold a permanent magnet carrier in place. The solenoids are excited separately to generate restoring forces when the permanent magnet carrier is displaced from its equilibrium position. The research uses the ANSOFT finite element analysis simulation to analyze the solenoid restoring forces and to motivate a suitable permanent magnets arrangement. Active control on the solenoid currents is then used to maintain the carrier position. The system identification is carried out by perturbing the experimental set-up from its equilibrium position. The simulation results based on the identification models show that simple control is effective for maintaining the carrier position. Initial implementation has also showed that the concept is feasible

  9. Low Complexity Beampattern Design in MIMO Radars Using Planar Array

    KAUST Repository

    Bouchoucha, Taha

    2015-01-07

    In multiple-input multiple-output radar systems, it is usually desirable to steer transmitted power in the region-of-interest. To do this, conventional methods optimize the waveform covariance matrix, R, for the desired beampattern, which is then used to generate actual transmitted waveforms. Both steps require constrained optimization, therefore, use iterative and expensive algorithms. In this paper, we provide a closed-form solution to design covariance matrix for the given beampattern using the planar array, which is then used to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope (FACE) waveforms. The proposed algorithm exploits the two-dimensional fast-Fourier-transform. The performance of our proposed algorithm is compared with existing methods that are based on semi-definite quadratic programming with the advantage of a considerably reduced complexity.

  10. A novel magnetorheological damper based parallel planar manipulator design

    International Nuclear Information System (INIS)

    Hoyle, A; Arzanpour, S; Shen, Y

    2010-01-01

    This paper presents a novel parallel planar robot design which is low cost and simple in structure. The design addresses some of the problems, such as concentration of excessive load on the links and joints, due to wrong commanding signals being given by the controller. In this application two of the conventional actuators are replaced by magnetorheological (MR) dampers, and only one actuator is used to generate motion. The design paradigm is based on the concept that a moving object 'intuitively' follows the path with minimum resistance to its motion. This implies that virtual adoptable constraints can be used effectively to define motion trajectories. In fact, motion generation and adaptive constraints are two elements essential to implementing this strategy. In this paper, MR dampers are used to provide adjustable constraints and to guide the platform that is moved by the linear motor. The model of the MR dampers is derived using the Bouc–Wen model. This model is then used for manipulator simulation and controller design. Two controllers are developed for this manipulator: (1) a closed loop on/off one and (2) a proportional–derivative controller. Also, three different trajectories are defined and used for both the simulations and experiments. The results indicate a good agreement between the simulations and experiments. The experimental results also demonstrate the capability of the manipulator for following sophisticated trajectories

  11. Diesel Fueled SOFC for Class 7/Class 8 On-Highway Truck Auxiliary Power

    Energy Technology Data Exchange (ETDEWEB)

    Vesely, Charles John-Paul [Cummins Power Generation; Fuchs, Benjamin S. [Cummins Power Generation; Booten, Chuck W. [Protonex Technology, LLC

    2010-03-31

    The following report documents the progress of the Cummins Power Generation (CPG) Diesel Fueled SOFC for Class 7/Class 8 On-Highway Truck Auxiliary Power (SOFC APU) development and final testing under the U.S. Department of Energy (DOE) Energy Efficiency and Renewable Energy (EERE) contract DE-FC36-04GO14318. This report overviews and summarizes CPG and partner development leading to successful demonstration of the SOFC APU objectives and significant progress towards SOFC commercialization. Significant SOFC APU Milestones: Demonstrated: Operation meeting SOFC APU requirements on commercial Ultra Low Sulfur Diesel (ULSD) fuel. SOFC systems operating on dry CPOX reformate. Successful start-up and shut-down of SOFC APU system without inert gas purge. Developed: Low cost balance of plant concepts and compatible systems designs. Identified low cost, high volume components for balance of plant systems. Demonstrated efficient SOFC output power conditioning. Demonstrated SOFC control strategies and tuning methods.

  12. The ways of SOFC systems efficiency increasing

    Energy Technology Data Exchange (ETDEWEB)

    Demin, A.K.; Timofeyeva, N.

    1996-04-01

    The efficiency of solid oxide fuel cells (SOFCs) is described. This paper considers methods to lift the fuel utilization and/or the average cell voltage with the goal of increasing the cell efficiency by improved cell designs.

  13. Design and measurements of the double layer planar motor

    NARCIS (Netherlands)

    Rovers, J.M.M.; Jansen, J.W.; Lomonova, E.

    2013-01-01

    Moving-magnet magnetically levitated planar motors are considered for use as a wafer stage in the semiconductor lithographic industry. This puts high requirements on the accuracy and the dissipated power and cooling performance of such motors. A novel planar motor topology is developed, which

  14. Design and construction of a planar motion mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Tanasovici, Gilberto [Protemaq Engenharia e Projetos, Santo Andre, SP (Brazil); Fucatu, Carlos H. [Technomar Engenharia Ltda., Sao Paulo, SP (Brazil); Tannuri, Eduardo A. [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Mecatronica; Umeda, Carlos H. [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

    2008-07-01

    This paper describes the design and construction of a PMM (Planar Motion Mechanism) towed by the IPT-SP main carriage. The IPT towing tank no. 2 is 220 m length and 6.6 m wide. The PMM provides a forced sway and/or yaw oscillation on a ship or other marine structure scaled model.. The maximum sway amplitude (transversal motion) is {+-}1 m, and the maximum sway velocity is 1.0 m/s, with a maximum carrying load of 1000 N. The maximum yaw velocity (rotation motion) is 36 deg/s. High-precision components were used in the construction, and the final estimated accuracy in the sway axis is 0.02 mm and approximately 0.1 deg for yaw motions. Finite Element Analysis and Structural Optimization techniques were used during the design stage. The PMM structure total mass is less than 1 ton, lighter than similar mechanisms in other institutions. A Man-Machine Interface was developed, and the operator is able to define the period and amplitude of sway and yaw motions, as well as the fade-in and fade-out time. An integral 3-component force load cell is installed in the end of the support axis, which measures the hydrodynamic loads on the captive model at low speed tests. This novel laboratorial facility allows the IPT to execute new kinds of experimental procedures, related to evaluation of hydrodynamic loads acting on ship hulls and offshore structures. (author)

  15. Optimal Design and Operation of A Syngas-fuelled SOFC Micro-CHP System for Residential Applications in Different Climate Zones in China

    DEFF Research Database (Denmark)

    Yang, Wenyuan; Liso, Vincenzo; Zhao, Yingru

    2013-01-01

    heat-to-power load ratio. Therefore, the aim of this study is to investigate the optimal design and operation of a syngas-fuelled SOFC micro-CHP system for small households located in five different climate zones in China. The ability of the micro-CHP to cover the heat and electricity demand of a 70m2...... demand. Numerical simulations are conducted in Matlab environment. System design trade-offs are discussed to determine the optimal match between the energy demand of the household for different climates across China and the energy supply of the micro-CHP during the whole year. Moreover, criteria...

  16. Surfaces foliated by planar geodesics: a model forcurved wood design

    DEFF Research Database (Denmark)

    Brander, David; Gravesen, Jens

    2017-01-01

    Surfaces foliated by planar geodesics are a natural model for surfaces made from wood strips. We outline how to construct all solutions, and produce non-trivial examples, such as a wood-strip Klein bottle......Surfaces foliated by planar geodesics are a natural model for surfaces made from wood strips. We outline how to construct all solutions, and produce non-trivial examples, such as a wood-strip Klein bottle...

  17. Design of a planar 3-DOF parallel micromanipulator

    International Nuclear Information System (INIS)

    Lee, Jeong Jae; Dong, Yanlu; Jeon, Yong Ho; Lee, Moon Gu

    2013-01-01

    A planar three degree-of-freedom (DOF) parallel manipulator is proposed to be applied for alignment during assembly of microcomponents. It adopts a PRR (prismatic-revolute-revolute) mechanism to meet the requirements of high precision for assembly and robustness against disturbance. The mechanism was designed to have a large workspace and good dexterity because parallel mechanisms usually have a narrow range and singularity of motion compared to serial mechanisms. Inverse kinematics and a simple closed-loop algorithm of the parallel manipulator are presented to control it. Experimental tests have been carried out with high-resolution capacitance sensors to verify the performance of the mechanism. The results of experiments show that the manipulator has a large workspace of ±1.0 mm, ±1.0 mm, and ±10 mrad in the X-, Y-, and θ-directions, respectively. This is a large workspace when considering it adopts a parallel mechanism and has a small size, 100 ´ 100 ´ 100 mm3 . It also has a good precision of 2 μm, 3 μm, and 0.2 mrad, in the X-, Y-, and θ- axes, respectively. These are high resolutions considering the manipulator adopts conventional joints. The manipulator is expected to have good dexterity.

  18. Development of planar solid oxide fuel cells for power generation applications

    Energy Technology Data Exchange (ETDEWEB)

    Minh, N.Q. [AlliedSignal Aerospce Equipment Systems, Torrance, CA (United States)

    1996-04-01

    Planar solid oxide fuel cells (SOFCs) are presently being developed for a variety of electric power generation application. The planar design offers simple cell geometry, high power density, and multiple fabrication and gas manifolding options. Planar SOFC technology has received much attention recently, and significant progress has been made in this area. Recent effort at AlliedSignal has focused on the development of high-performance, lightweight planar SOFCs, having thin-electrolyte films, that can be operated efficiently at reduced temperatures (< 1000{degrees}C). The advantages of reduced-temperature operation include wider material choice (including use of metallic interconnects), expected longer cell life, reduced thermal stress, improved reliability, and reduced fuel cell cost. The key aspect in the development of thin-film SIFCs is to incorporate the thin electrolyte layer into the desired structure of cells in a manner that yields the required characteristics. AlliedSignal has developed a simple and cost-effective method based on tape calendering for the fabrication of thin-electrolyte SOFCs. Thin-electrolyte cells made by tape calendering have shown extraordinary performance, e.g., producing more than 500mW/cm{sup 2} at 700{degrees}C and 800mW/cm{sup 2} at 800{degrees}C with hydrogen as fuel and air is oxidant. thin-electrolyte single cells have been incorporated into a compliant metallic stack structure and operated at reduced and operated at reduced-temperature conditions.

  19. Overview of analytical models for the design of linear and planar motors

    NARCIS (Netherlands)

    Jansen, J.W.; Smeets, J.P.C.; Overboom, T.T.; Rovers, J.M.M.; Lomonova, E.A.

    2014-01-01

    In this paper, an overview of analytical techniques for the modeling of linear and planar permanent-magnet motors is given. These models can be used complementary to finite element analyses for fast evaluations of topologies, but they are indispensable for the design of magnetically levitated planar

  20. Materials Properties Database for Selection of High-Temperature Alloys and Concepts of Alloy Design for SOFC Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z Gary; Paxton, Dean M.; Weil, K. Scott; Stevenson, Jeffry W.; Singh, Prabhakar

    2002-11-24

    To serve as an interconnect / gas separator in an SOFC stack, an alloy should demonstrate the ability to provide (i) bulk and surface stability against oxidation and corrosion during prolonged exposure to the fuel cell environment, (ii) thermal expansion compatibility with the other stack components, (iii) chemical compatibility with adjacent stack components, (iv) high electrical conductivity of the surface reaction products, (v) mechanical reliability and durability at cell exposure conditions, (vii) good manufacturability, processability and fabricability, and (viii) cost effectiveness. As the first step of this approach, a composition and property database was compiled for high temperature alloys in order to assist in determining which alloys offer the most promise for SOFC interconnect applications in terms of oxidation and corrosion resistance. The high temperature alloys of interest included Ni-, Fe-, Co-base superal

  1. Fundamental Investigations and Rational Design of Durable High-Performance SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Georgia Inst. of Technology, Atlanta, GA (United States); Ding, Dong [Georgia Inst. of Technology, Atlanta, GA (United States); Wei, Tao [Georgia Inst. of Technology, Atlanta, GA (United States); Liu, Meilin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2016-03-31

    The main objective of this project is to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants, aiming towards the rational design of cathodes with high-performance and enhanced durability by combining a porous backbone (such as LSCF) with a thin catalyst coating. The mechanistic understanding will help us to optimize the composition and morphology of the catalyst layer and microstructure of the LSCF backbone for better performance and durability. More specifically, the technical objectives include: (1) to unravel the degradation mechanism of LSCF cathodes under realistic operating conditions with different types of contaminants using in situ and ex situ measurements performed on specially-designed cathodes; (2) to examine the microstructural and compositional evolution of LSCF cathodes as well as the cathode/electrolyte interfaces under realistic operating conditions; (3) to correlate the fuel cell performance instability and degradation with the microstructural and morphological evolution and surface chemistry change of the cathode under realistic operating conditions; (4) to explore new catalyst materials and electrode structures to enhance the stability of the LSCF cathode under realistic operating conditions; and (5) to validate the long term stability of the modified LSCF cathode in commercially available cells under realistic operating conditions. We have systematically evaluated LSCF cathodes in symmetrical cells and anode supported cells under realistic conditions with different types of contaminants such as humidity, CO2, and Cr. Electrochemical models for the design of test cells and understanding of mechanisms have been developed for the exploration of fundamental properties of electrode materials. It is demonstrated that the activity and stability of LSCF cathodes can be degraded by the introduction of contaminants. The microstructural and compositional evolution of LSCF

  2. Electrode design for direct-methane micro-tubular solid oxide fuel cell (MT-SOFC)

    Science.gov (United States)

    Rabuni, Mohamad Fairus; Li, Tao; Punmeechao, Puvich; Li, Kang

    2018-04-01

    Herein, a micro-structured electrode design has been developed via a modified phase-inversion method. A thin electrolyte integrated with a highly porous anode scaffold has been fabricated in a single-step process and developed into a complete fuel cell for direct methane (CH4) utilisation. A continuous and well-dispersed layer of copper-ceria (Cu-CeO2) was incorporated inside the micro-channels of the anode scaffold. A complete cell was investigated for direct CH4 utilisation. The well-organised micro-channels and nano-structured Cu-CeO2 anode contributed to an increase in electrochemical reaction sites that promoted charge-transfer as well as facilitating gaseous fuel distribution, resulting in outstanding performances. Excellent electrochemical performances have been achieved in both hydrogen (H2) and CH4 operation. The power density of 0.16 Wcm-2 at 750 °C with dry CH4 as fuel is one of the highest ever reported values for similar anode materials.

  3. Study on AN Intermediate Temperature Planar Sofc

    Science.gov (United States)

    Wang, Shaorong; Cao, Jiadi; Chen, Wenxia; Lu, Zhiyi; Wang, Daqian; Wen, Ting-Lian

    An ITSOFC consisted of Ni/YSZ anode supported YSZ composite thin film and La0.6Sr0.4CoO3 (LSCO) cathode combined with a Ce0.8Sm0.2O1.9 (CSO) interlayer was studied. Tape cast method was applied to prepare green sheets of Ni/YSZ anode supported YSZ composite thin film. After isostatic pressing and cosintering, the YSZ film on the Ni/YSZ anode was gas-tight dense, and 15-30μm thick. The area of the composite film was over 100 cm2. A CSO interlayer was sintered on to the YSZ electrolyte film to protect LSCO cathode from reaction with YSZ at high temperatures. The LSCO cathode layer was screen printed onto the CSO interlayer and sintered at 1200°C for 3h to form a single cell. The obtained single cell was operated with H2 as fuel and O2 as oxidant. The cell performance and impedance were measured and discussed relating with the component contributions.

  4. Optimal Design and Tradeoff Analysis of Planar Transformer in High-Power DC–DC Converters

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2012-01-01

    The trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wire-wound magnetic component structures. A planar magnetic is a low-profile transformer or inductor utilizing planar windings, instead...... of the traditional windings made of Cu wires. In this paper, the most important factors for planar transformer (PT) design including winding loss, core loss, leakage inductance, and stray capacitance have individually been investigated. The tradeoffs among these factors have to be analyzed in order to achieve...

  5. Multilayer tape cast SOFC – Effect of anode sintering temperature

    DEFF Research Database (Denmark)

    Hauch, Anne; Birkl, Christoph; Brodersen, Karen

    2012-01-01

    Multilayer tape casting (MTC) is considered a promising, cost-efficient, up-scalable shaping process for production of planar anode supported solid oxide fuel cells (SOFC). Multilayer tape casting of the three layers comprising the half cell (anode support/active anode/electrolyte) can potentially...

  6. Selected applications of planar permanent magnet multipoles in FEL insertion device design

    International Nuclear Information System (INIS)

    Tatchyn, R.

    1993-08-01

    In recent work, a new class of magnetic multipoles based on planar configurations of permanent magnet (PM) material has been developed. These structures, in particular the quadrupole and sextupole, feature fully open horizontal apertures, and are comparable in effectiveness to conventional iron multipole structures. In this paper results of recent measurements of planar PM quadrupoles and sextupoles are reported and selected applications to FEL insertion device design are considered

  7. Design of a Compact Planar Rectenna for Wireless Power Transfer in the ISM Band

    OpenAIRE

    Fang Zhang; Xin Liu; Fan-Yi Meng; Qun Wu; Jong-Chul Lee; Jin-Feng Xu; Cong Wang; Nam-Young Kim

    2014-01-01

    This paper presents a compact planar rectenna with high conversion efficiency in the ISM band. The proposed rectenna is developed by the decomposing of a planar rectenna topology into two functional parts and then recombining the two parts into a new topology to make the rectenna size reduction. The operation mechanism of the antenna and rectifying circuit in the proposed novel topology is explained and the design methodology is presented in detail. The proposed topology not only reduces the ...

  8. Optimal design and operation of a syngas-fuelled SOFC micro CHP system for residential applications in different climate zones in China

    DEFF Research Database (Denmark)

    Yang, Wenyuan; Zhao, Yingru; Liso, Vincenzo

    2014-01-01

    under difference climate conditions to ensure that it is well matched with the local heat-to-power ratio. The aim of this study is to investigate the optimal design and operation of a syngas-fuelled SOFC micro-CHP system for small households located in five different climate zones in China. The ability...... of the micro-CHP to cover the heat and electricity demand of a 70 m2 single-family apartment with an average number of occupants of 3 is evaluated. A detailed model of the micro-CHP unit coupled with a hot water storage tank and an auxiliary boiler is developed. System design trade-offs are discussed...

  9. Computer experimental analysis of the CHP performance of a 100 kW e SOFC Field Unit by a factorial design

    Science.gov (United States)

    Calì, M.; Santarelli, M. G. L.; Leone, P.

    Gas Turbine Technologies (GTT) and Politecnico di Torino, both located in Torino (Italy), have been involved in the design and installation of a SOFC laboratory in order to analyse the operation, in cogenerative configuration, of the CHP 100 kW e SOFC Field Unit, built by Siemens-Westinghouse Power Corporation (SWPC), which is at present (May 2005) starting its operation and which will supply electric and thermal power to the GTT factory. In order to take the better advantage from the analysis of the on-site operation, and especially to correctly design the scheduled experimental tests on the system, we developed a mathematical model and run a simulated experimental campaign, applying a rigorous statistical approach to the analysis of the results. The aim of this work is the computer experimental analysis, through a statistical methodology (2 k factorial experiments), of the CHP 100 performance. First, the mathematical model has been calibrated with the results acquired during the first CHP100 demonstration at EDB/ELSAM in Westerwoort. After, the simulated tests have been performed in the form of computer experimental session, and the measurement uncertainties have been simulated with perturbation imposed to the model independent variables. The statistical methodology used for the computer experimental analysis is the factorial design (Yates' Technique): using the ANOVA technique the effect of the main independent variables (air utilization factor U ox, fuel utilization factor U F, internal fuel and air preheating and anodic recycling flow rate) has been investigated in a rigorous manner. Analysis accounts for the effects of parameters on stack electric power, thermal recovered power, single cell voltage, cell operative temperature, consumed fuel flow and steam to carbon ratio. Each main effect and interaction effect of parameters is shown with particular attention on generated electric power and stack heat recovered.

  10. Design of planar chiral metamaterials for near-infrared regime

    Science.gov (United States)

    Kaya, Sabri; Turkmen, Mustafa; Topaktas, Omer

    2017-01-01

    Planar chiral metamaterials (PCMs) comprising double-layer dielectric-metal-dielectric resonant structures in the shape of a windmill are presented for near-infrared regime. The circular dichroism is retrieved from transmission spectra. Effects of used materials on circular dichroism characteristics of PCM arrays are investigated for the first time. The dependence of spectral characteristics on the geometrical parameters of the PCMs is analyzed by the finite-difference time-domain method. The observations indicated that the circular dichroism characteristics of the proposed PCM arrays are strongly dependent on the type of metal and dielectric materials. Due to the enhanced chiroptical near-field response and tunable spectral behavior, proposed PCM arrays may have potential for biosensing applications of chiral biomolecules.

  11. Multi-objective design and operation of Solid Oxide Fuel Cell (SOFC) Triple Combined-cycle Power Generation systems: Integrating energy efficiency and operational safety

    International Nuclear Information System (INIS)

    Sharifzadeh, Mahdi; Meghdari, Mojtaba; Rashtchian, Davood

    2017-01-01

    Highlights: • Integrating Solid Oxide Fuel Cells with thermal power plants enhance overall energy efficiency. • However, the high degree of process integration in hybrid power plants limits the operating window. • Multi-objective optimization was applied for integrated design and operation. • The Pareto optimal solutions demonstrated strong trade-off between energy efficiency and operational safety. - Abstract: Energy efficiency is one of the main pathways for energy security and environmental protection. In fact, the International Energy Agency asserts that without energy efficiency, 70% of targeted emission reductions are not achievable. Despite this clarity, enhancing the energy efficiency introduce significant challenge toward process operation. The reason is that the methods applied for energy-saving pose the process operation at the intersection of safety constraints. The present research aims at uncovering the trade-off between safe operation and energy efficiency; an optimization framework is developed that ensures process safety and simultaneously optimizes energy-efficiency, quantified in economic terms. The developed optimization framework is demonstrated for a solid oxide fuel cell (SOFC) power generation system. The significance of this industrial application is that SOFC power plants apply a highly degree of process integration resulting in very narrow operating windows. However, they are subject to significant uncertainties in power demand. The results demonstrate a strong trade-off between the competing objectives. It was observed that highly energy-efficient designs feature a very narrow operating window and limited flexibility. For instance, expanding the safe operating window by 100% will incur almost 47% more annualized costs. Establishing such a trade-off is essential for realizing energy-saving.

  12. A Compact Design of Planar Array Antenna with Fractal Elements for Future Generation Applications

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2016-01-01

    In this paper, a planar phased array fractal antenna for the future fifth generation (5G) applications is presented. The proposed array antenna is designed to operate at 22 GHz. 64 patch antenna elements with coaxial-probe feeds have been used for the proposed design. The antenna elements are based...... on Vicsek fractal geometry where the third iteration patches operate over a wide bandwidth and contribute to improve the efficiency and realized gain performance. The designed planar array has more than 22 dB realized gain and -0.3 dB total efficiency when its beam is tilted to 0 degrees elevation...

  13. Towards Multi Fuel SOFC Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Clausen, Lasse Røngaard; Bang-Møller, Christian

    2011-01-01

    Complete Solid Oxide Fuel Cell (SOFC) plants fed by several different fuels are suggested and analyzed. The plants sizes are about 10 kW which is suitable for single family house with needs for both electricity and heat. Alternative fuels such as, methanol, DME (Di-Methyl Ether) and ethanol...... are also considered and the results will be compared with the base plant fed by Natural Gas (NG). A single plant design will be suggested that can be fed with methanol, DME and ethanol whenever these fuels are available. It will be shown that the plant fed by ethanol will have slightly higher electrical...

  14. Aluminosilicate-based sealants for SOFCs and other electrochemical applications - A brief review

    Science.gov (United States)

    Tulyaganov, Dilshat U.; Reddy, Allu Amarnath; Kharton, Vladislav V.; Ferreira, José M. F.

    2013-11-01

    Among different designs of solid oxide fuel cells (SOFCs), planar design is the most promising due to easier fabrication, improved performance and relatively high power density. In planar SOFCs and other solid-electrolyte devices, gas-tight seals must be formed along the edges of each cell and between the stack and gas manifolds. For a sealant to work effectively in high-temperature SOFC environment, equilibrium needs to be achieved amid its mechanical properties and flow behavior so that it does not only maintain its hermeticity at high temperature but is also able to reduce mechanical stresses generated in the seal during thermal cycling. The most common sealants based on glass or glass-ceramic materials have been shown to operate in fuel cells for more than 1000 h with no significant degradation. Analysis of the current literature sources demonstrated that from thermal and chemical stability points of view, silicate based glass systems are more suitable than borate and borosilicate glass systems. In this work, different glass-ceramic (GC) compositions based on alkaline- and alkaline-earth aluminosilicate-based glass systems are reviewed with a special emphasis on their thermal, chemical, mechanical, and electrical properties. Based on these considerations, glass composition design approaches are provided that aid in search of the best seal glasses satisfying the rigid functional requirements. Among all the glass systems studied, a pyroxene based CaO-MgO-SrO-BaO-La2O3-Al2O3-SiO2 seal GC compositions have been specifically discussed because those have achieved appropriate thermal and chemical properties along with high stability. Approaches for further developments and optimization of GC sealants are briefly discussed.

  15. SOFC interface studies

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Bay, Lasse; West, Keld

    performance and inductive hysteresis phenomena often observed in SOFC kinetic studies (\\ref{TJ01}). Fig.\\,\\ref{cath_laser} shows the YSZ surface developed below a Pt point electrode polarised at -0.10\\, V at $1000^\\circ$C for a period of 85 days. The structural as well as the compositional changes...

  16. Design of planar articulated mechanisms using branch and bound

    DEFF Research Database (Denmark)

    Stolpe, Mathias; Kawamoto, Atsushi

    2004-01-01

    This paper considers an optimization model and a solution method for the design of two-dimensional mechanical mechanisms. The mechanism design problem is modeled as a nonconvex mixed integer program which allows the optimal topology and geometry of the mechanism to be determined simultaneously...... and that buckling is prevented. The feasible set of the design problem is described by nonlinear differentiable and non-differentiable constraints as well as nonlinear matrix inequalities. To solve the mechanism design problem a branch and bound method based on convex relaxations is developed. To guarantee...... mechanism design problems of realistic size to global optimality....

  17. Status of the TMI SOFC system

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, R.C.; Petrik, M.A.; Cable, T.L. [Technology Management, Inc., Cleveland, OH (United States)

    1996-12-31

    TMI has completed preliminary engineering designs for complete 20kW SOFC systems modules for stationary distributed generation applications using pipeline natural gas [sponsored by Rochester Gas and Electric (Rochester, New York) and EPRI (Palo Alto, California)]. Subsystem concepts are currently being tested.

  18. Planar articulated mechanism design by graph theoretical enumeration

    DEFF Research Database (Denmark)

    Kawamoto, A; Bendsøe, Martin P.; Sigmund, Ole

    2004-01-01

    This paper deals with design of articulated mechanisms using a truss-based ground-structure representation. By applying a graph theoretical enumeration approach we can perform an exhaustive analysis of all possible topologies for a test example for which we seek a symmetric mechanism. This guaran....... This guarantees that one can identify the global optimum solution. The result underlines the importance of mechanism topology and gives insight into the issues specific to articulated mechanism designs compared to compliant mechanism designs....

  19. Design of planar articulated mechanisms using branch and bound

    DEFF Research Database (Denmark)

    Stolpe, Mathias; Kawamoto, Atsushi

    2005-01-01

    This paper considers an optimization model and a solution method for the design of two-dimensional mechanical mechanisms. The mechanism design problem is modeled as a nonconvex mixed integer program which allows the optimal topology and geometry of the mechanism to be determined simultaneously...

  20. Design and construction of planar mm-wave accelerating cavity structures

    International Nuclear Information System (INIS)

    Kang, Y.W.; Kustom, R.L.; Nassiri, A.; Song, J.J.; Feineman, A.D.; Illinois Univ., Chicago, IL

    1995-01-01

    Feasibility studies on the planar millimeter-wave cavity structures have been made. The structures could be used for linear accelerators, free electron lasers, mm-wave amplifiers, or mm-wave undulators. The cavity structures are intended to be manufactured by using DXL (deep x-ray lithography) microfabrication technology. The frequency of operation can be about 30GHz to 300GHz. For most applications, a complete structure consists of two identical planar half structures put together face-to-face. Construction and properties of constant gradient structures that have been investigated so far will be discussed. These cavity structures have been designed for 120GHz 2π/3-mode operation

  1. Design and analysis of planar printed microwave and PBG filters using an FDTD method

    DEFF Research Database (Denmark)

    Tong, M.S.; Lu, Y.L.; Chen, Y.C.

    2004-01-01

    In this paper, various planar printed microwave and photonic band-gap (PBG) filters have been designed and analyzed by applying the finite difference time domain method, together with an unsplit-anisotropic perfectly matched layer technique as treatments of boundary conditions. The implemented so...

  2. Direct Closed-Form Design of Finite Alphabet Constant Envelope Waveforms for Planar Array Beampatterns

    KAUST Repository

    Bouchoucha, Taha

    2015-01-01

    them hard to use in practice especially for real time radar applications. In this paper, we provide a closed-form solution to design the covariance matrix for a given beampattern in the three dimensional space using planar arrays, which is then used

  3. Low Complexity Beampattern Design in MIMO Radars Using Planar Array

    KAUST Repository

    Bouchoucha, Taha; Ahmed, Sajid; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

    2015-01-01

    is then used to generate actual transmitted waveforms. Both steps require constrained optimization, therefore, use iterative and expensive algorithms. In this paper, we provide a closed-form solution to design covariance matrix for the given beampattern using

  4. Manufacturing of anode supported SOFCs: Processing parameters and their influence

    DEFF Research Database (Denmark)

    Ramousse, Severine; Menon, Mohan; Brodersen, Karen

    2007-01-01

    The establishment of low cost, highly reliable and reproducible manufacturing processes has been focused for commercialization of SOFC technology. A major challenge in the production chain is the manufacture of anode-supported planar SOFC's single cells in which each layer in a layered structure...... contains a complex microstructure. In order to improve the cell performance as well as reducing the processing costs, it has been found necessary to consider the process chain holistically, because successful manufacture of such a cell and the achievement of optimal final properties depend on each...... of the processing steps and their interdependence. A large database for several thousand anode-supported SOFCs manufactured annually at the Risoe National Laboratory in collaboration with Topsoe Fuel Cell A/S has been constructed. This enables a statistical analysis of the various controlling parameters. Some...

  5. Status of SOFC development at Siemens

    Energy Technology Data Exchange (ETDEWEB)

    Drenckhahn, W.; Blum, L.; Greiner, H. [Siemens AG, Erlangen (Germany)

    1996-12-31

    The Siemens SOFC development programme reached an important milestone in June 1995. A stack operating with hydrogen and oxygen produced a peak power of 10.7 kW at a current density of 0.7 A/cm{sup 2} and was running for more than 1400 hours. The SOFC configuration is based on a flat metal separator plate using the multiple cell array design. Improved PENs, functional layer and joining technique were implemented. Based on this concept, a 100 kW plant was designed The SOFC development at Siemens has been started in 1990 after a two years preparation phase. The first period with the goal of the demonstration of a 1 kW SOFC stack operation ended in 1993. This important milestone was finally reached in the begin of 1994. The second project phase with the final milestone of a 20 kW module operation will terminate at the end of 1996. This result will form a basis for the next phase in which a 50 to 100 kW pilot plant will be built and tested.

  6. Facts and figures, an International Energy Agency SOFC task report

    Energy Technology Data Exchange (ETDEWEB)

    Bossel, U G; Dubal, L [ed.

    1992-04-15

    The report covers the following themes: SOFC chemistry, properties of SOFC gases and materials, electrochemistry, electric current flow in SOFC elements, SOFC configurations, mass flow phenomena and linearized SOFC performance analysis. figs., tabs., 27 refs.

  7. Design and investigation of properties of nanocrystalline diamond optical planar waveguides.

    Science.gov (United States)

    Prajzler, Vaclav; Varga, Marian; Nekvindova, Pavla; Remes, Zdenek; Kromka, Alexander

    2013-04-08

    Diamond thin films have remarkable properties comparable with natural diamond. Because of these properties it is a very promising material for many various applications (sensors, heat sink, optical mirrors, chemical and radiation wear, cold cathodes, tissue engineering, etc.) In this paper we report about design, deposition and measurement of properties of optical planar waveguides fabricated from nanocrystalline diamond thin films. The nanocrystalline diamond planar waveguide was deposited by microwave plasma enhanced chemical vapor deposition and the structure of the deposited film was studied by scanning electron microscopy and Raman spectroscopy. The design of the presented planar waveguides was realized on the bases of modified dispersion equation and was schemed for 632.8 nm, 964 nm, 1 310 nm and 1 550 nm wavelengths. Waveguiding properties were examined by prism coupling technique and it was found that the diamond based planar optical element guided one fundamental mode for all measured wavelengths. Values of the refractive indices of our NCD thin film measured at various wavelengths were almost the same as those of natural diamond.

  8. The Design of Polymer Planar Optical Triplexer with MMI Filter and Directional Coupler

    Directory of Open Access Journals (Sweden)

    V. Jerabek

    2013-12-01

    Full Text Available Optical bidirectional WDM transceiver is a key component of the Passive Optical Network of the Fiber to the Home topology. Essential parts of such transceivers are filters that combine multiplexing and demultiplexing function of optical signal (triplexing filters. In this paper we report about a design of a new planar optical multi-wavelength selective system triplexing filter, which combines a multimode interference filter with directional coupler based on the epoxy polymer SU-8 on Si/SiO2 substrate. The optical triplexing filter was designed using the Beam Propagation Method. The aim of this project was to optimize the triplexing filter optical parameters and to minimize the planar optical wavelength selective system dimensions. The multimode interference filter was used for separation of downstream optical signal in designed optoelectronic integrated WDM transceiver. The directional coupler was used for adding of upstream optical signal.

  9. Design of a Compact Planar Rectenna for Wireless Power Transfer in the ISM Band

    Directory of Open Access Journals (Sweden)

    Fang Zhang

    2014-01-01

    Full Text Available This paper presents a compact planar rectenna with high conversion efficiency in the ISM band. The proposed rectenna is developed by the decomposing of a planar rectenna topology into two functional parts and then recombining the two parts into a new topology to make the rectenna size reduction. The operation mechanism of the antenna and rectifying circuit in the proposed novel topology is explained and the design methodology is presented in detail. The proposed topology not only reduces the rectenna design cycle time but also leads to easy realization at the required frequency ranges with a very low cost. For validation, a 2.45 GHz rectenna system is designed and measured to show their microwave performances.

  10. Power generation efficiency of an SOFC-PEFC combined system with time shift utilization of SOFC exhaust heat

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Shin' ya [Power Engineering Lab., Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Kouen-cho, Kitami, Hokkaido 0908507 (Japan)

    2010-01-15

    A microgrid, with little environmental impact, is developed by introducing a combined SOFC (solid oxide fuel cell) and PEFC (proton exchange membrane fuel cell) system. Although the SOFC requires a higher operation temperature compared to the PEFC, the power generation efficiency of the SOFC is higher. However, if high temperature exhaust heat may be used effectively, a system with higher total power generation efficiency can be built. Therefore, this paper investigates the operation of a SOFC-PEFC combined system, with time shift operation of reformed gas, into a microgrid with 30 houses in Sapporo, Japan. The SOFC is designed to correspond to base load operation, and the exhaust heat of the SOFC is used for production of reformed gas. This reformed gas is used for the production of electricity for the PEFC, corresponding to fluctuation load of the next day. Accordingly, the reformed gas is used with a time shift operation. In this paper, the relation between operation method, power generation efficiency, and amount of heat storage of the SOFC-PEFC combined system to the difference in power load pattern was investigated. The average power generation efficiency of the system can be maintained at nearly 48% on a representative day in February (winter season) and August (summer season). (author)

  11. Design of planar electron gun for UHF range, CW power inductive output tube

    International Nuclear Information System (INIS)

    Kaushik, Meenu; Joshi, L.M.

    2015-01-01

    Inductive Output Tube (lOT) is an amplifier which is now-a-days in demand for scientific applications. For every vacuum tube, electron gun is an important part and in fact considered as the heart of the tube. Hence, designing of this component is very crucial for efficient operation of the device throughout its lifetime. This paper is all about the electromagnetic (EM) design of planar electron gun of 40 kV, 3.5 A beam voltage and beam current respectively, for a 100 kW CW power lOT operating in UHF range. The design considerations and basic equations involved in its design are included in the paper. The gun structure has been optimized for getting the desired beam characteristics. The simulation results including the beam profile along with the beam current are shown using two commercial codes namely TRAK and MAGIC code. Planar shape of electron beam reduces space charge forces in the beam itself and consequently beam energy spread for a given current. The magnetic focusing of planar beam is easier comparative to spherical beam hence, this structure has been adopted for this particular device design. (author)

  12. Design of coated standing nanowire array solar cell performing beyond the planar efficiency limits

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yang; Ye, Qinghao; Shen, Wenzhong, E-mail: wzshen@sjtu.edu.cn [Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2016-05-28

    The single standing nanowire (SNW) solar cells have been proven to perform beyond the planar efficiency limits in both open-circuit voltage and internal quantum efficiency due to the built-in concentration and the shifting of the absorption front. However, the expandability of these nano-scale units to a macro-scale photovoltaic device remains unsolved. The main difficulty lies in the simultaneous preservation of an effective built-in concentration in each unit cell and a broadband high absorption capability of their array. Here, we have provided a detailed theoretical guideline for realizing a macro-scale solar cell that performs furthest beyond the planar limits. The key lies in a complementary design between the light-trapping of the single SNWs and that of the photonic crystal slab formed by the array. By tuning the hybrid HE modes of the SNWs through the thickness of a coaxial dielectric coating, the optimized coated SNW array can sustain an absorption rate over 97.5% for a period as large as 425 nm, which, together with the inherited carrier extraction advantage, leads to a cell efficiency increment of 30% over the planar limit. This work has demonstrated the viability of a large-size solar cell that performs beyond the planar limits.

  13. Progress in understanding SOFC electrodes

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Hansen, Karin Vels; Jørgensen, M.J.

    2002-01-01

    The literature of SOFC electrode kinetics and mechanisms is full of contradicting details in case of both the SOFC anode and cathode processes. Only weak patterns may be identified. One interpretation is that each of the reported data sets reflects a laboratory specific nature of each of the elec...

  14. Deployable and Conformal Planar Micro-Devices: Design and Model Validation

    Directory of Open Access Journals (Sweden)

    Jinda Zhuang

    2014-08-01

    Full Text Available We report a design concept for a deployable planar microdevice and the modeling and experimental validation of its mechanical behavior. The device consists of foldable membranes that are suspended between flexible stems and actuated by push-pull wires. Such a deployable device can be introduced into a region of interest in its compact “collapsed” state and then deployed to conformally cover a large two-dimensional surface area for minimally invasive biomedical operations and other engineering applications. We develop and experimentally validate theoretical models based on the energy minimization approach to examine the conformality and figures of merit of the device. The experimental results obtained using model contact surfaces agree well with the prediction and quantitatively highlight the importance of the membrane bending modulus in controlling surface conformality. The present study establishes an early foundation for the mechanical design of this and related deployable planar microdevice concepts.

  15. Design and investigation of properties of nanocrystalline diamond optical planar waveguides

    Czech Academy of Sciences Publication Activity Database

    Prajzler, V.; Varga, Marián; Nekvindová, P.; Remeš, Zdeněk; Kromka, Alexander

    2013-01-01

    Roč. 21, č. 7 (2013), s. 8417-8425 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GAP108/11/0794; GA MŠk LH12186; GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : waveguides, planar * diamond machining * optical design and fabrication Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.525, year: 2013

  16. Planar air-bearing microgravity simulators: Review of applications, existing solutions and design parameters

    Science.gov (United States)

    Rybus, Tomasz; Seweryn, Karol

    2016-03-01

    All devices designed to be used in space must be thoroughly tested in relevant conditions. For several classes of devices the reduced gravity conditions are the key factor. In early stages of development and later due to financial reasons, the tests need to be done on Earth. However, in Earth conditions it is impossible to obtain a different gravity field independent on all linear and rotational spatial coordinates. Therefore, various test-bed systems are used, with their design driven by the device's specific needs. One of such test-beds are planar air-bearing microgravity simulators. In such an approach, the tested objects (e.g., manipulators intended for on-orbit operations or vehicles simulating satellites in a close formation flight) are mounted on planar air-bearings that allow almost frictionless motion on a flat surface, thus simulating microgravity conditions in two dimensions. In this paper we present a comprehensive review of research activities related to planar air-bearing microgravity simulators, demonstrating achievements of the most active research groups and describing newest trends and ideas, such as tests of landing gears for low-g bodies. Major design parameters of air-bearing test-beds are also reviewed and a list of notable existing test-beds is presented.

  17. SOFC mini-tubulares basadas en YSZ

    Directory of Open Access Journals (Sweden)

    Campana, R.

    2008-08-01

    Full Text Available Tubular SOFC have the advantage over planar SOFC of the low temperature sealing and more resistance to thermal shock. On the other hand the volumetric power density of tubular Fuel Cells goes with the inverse of the tube diameter which added to the faster warm-up kinetics makes low diameter tubular SOFC favorable for low power applications. Anode supported tubular SOFC of 3mm diameter and 150 mm length with YSZ electrolyte were fabricated and tested by V-I measurements using H2-Ar (5, 10, 100 vol% as fuel and air for the cathode. The NiO-YSZ tubes of about 400 μm thickness were produced by hydrostatic pressure and then coated with an YSZ film of 15-20 μm. The electrolyte was deposited using a manual aerograph. After sintering either Pt paste or LSF (with YSZ or SDC coatings of about 20-50 μm thickness were deposited for the cathode. The OCV of the cells were excellent, very close to the expected Nernst law prediction indicating that there were not gas leaks. The maximun electrical power of the cell was near to 500mW/cm2 at 850ºC operation temperature. Complex impedance measurements of the cells were performed in order to determine the resistance of the different cell components.

    La principal ventaja de las SOFC tubulares frente a las planares es el sellado de la cámara anódica y catódica a bajas temperaturas. Además la densidad de energía volumétrica de las pilas tubulares es inversamente proporcional al diámetro del tubo, que añadido a los tiempos cortos de encendido y apagado hacen que las mini-tubulares sean interesantes para usos de baja potencia. Se han fabricado y caracterizado SOFC tubulares soportadas en ánodo de 3mm de diámetro y de 150 mm de longitud, 400μm de espesor, con electrolito de YSZ depositado por spray de 15-20 μm. Los tubos de NiO-YSZ son producidos por prensado isostático. La caracterización eléctrica se ha realizado empleando H2-Ar como combustible an

  18. Design of planar microcoil-based NMR probe ensuring high SNR

    Science.gov (United States)

    Ali, Zishan; Poenar, D. P.; Aditya, Sheel

    2017-09-01

    A microNMR probe for ex vivo applications may consist of at least one microcoil, which can be used as the oscillating magnetic field (MF) generator as well as receiver coil, and a sample holder, with a volume in the range of nanoliters to micro-liters, placed near the microcoil. The Signal-to-Noise ratio (SNR) of such a probe is, however, dependent not only on its design but also on the measurement setup, and the measured sample. This paper introduces a performance factor P independent of both the proton spin density in the sample and the external DC magnetic field, and which can thus assess the performance of the probe alone. First, two of the components of the P factor (inhomogeneity factor K and filling factor η ) are defined and an approach to calculate their values for different probe variants from electromagnetic simulations is devised. A criterion based on dominant component of the magnetic field is then formulated to help designers optimize the sample volume which also affects the performance of the probe, in order to obtain the best SNR for a given planar microcoil. Finally, the P factor values are compared between different planar microcoils with different number of turns and conductor aspect ratios, and planar microcoils are also compared with conventional solenoids. These comparisons highlight which microcoil geometry-sample volume combination will ensure a high SNR under any external setup.

  19. Design of planar microcoil-based NMR probe ensuring high SNR

    Directory of Open Access Journals (Sweden)

    Zishan Ali

    2017-09-01

    Full Text Available A microNMR probe for ex vivo applications may consist of at least one microcoil, which can be used as the oscillating magnetic field (MF generator as well as receiver coil, and a sample holder, with a volume in the range of nanoliters to micro-liters, placed near the microcoil. The Signal-to-Noise ratio (SNR of such a probe is, however, dependent not only on its design but also on the measurement setup, and the measured sample. This paper introduces a performance factor P independent of both the proton spin density in the sample and the external DC magnetic field, and which can thus assess the performance of the probe alone. First, two of the components of the P factor (inhomogeneity factor K and filling factor η are defined and an approach to calculate their values for different probe variants from electromagnetic simulations is devised. A criterion based on dominant component of the magnetic field is then formulated to help designers optimize the sample volume which also affects the performance of the probe, in order to obtain the best SNR for a given planar microcoil. Finally, the P factor values are compared between different planar microcoils with different number of turns and conductor aspect ratios, and planar microcoils are also compared with conventional solenoids. These comparisons highlight which microcoil geometry-sample volume combination will ensure a high SNR under any external setup.

  20. SOFC Systems with Improved Reliability and Endurance

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein [Fuelcell Energy, Incorporated, Danbury, CT (United States)

    2015-12-31

    The overall goal of this U.S. Department of Energy (DOE) sponsored project was the development of Solid Oxide Fuel Cell (SOFC) technology suitable for ultra-efficient central power generation systems utilizing coal and natural gas fuels and featuring greater than 90% carbon dioxide capture. The specific technical objective of this project was to demonstrate, via analyses and testing, progress towards adequate stack life (≥ 4 years) and stack performance stability (degradation rate ≤ 0.2% per 1000 hours) in a low-cost SOFC stack design. This final technical report summarizes the progress made during the project period of 27 months. Significant progress was made in the areas of cell and stack technology development, stack module development, sub-scale module tests, and Proof-of-Concept Module unit design, fabrication and testing. The work focused on cell and stack materials and designs, balance-of-plant improvements, and performance evaluation covering operating conditions and fuel compositions anticipated for commercially-deployed systems. In support of performance evaluation under commercial conditions, this work included the design, fabrication, siting, commissioning, and operation of a ≥ 50 kWe proof-of-concept module (PCM) power plant, based upon SOFC cell and stack technology developed to date by FuelCell Energy, Inc. (FCE) under the Office of Fossil Energy’s Solid Oxide Fuel Cells program. The PCM system was operated for at least 1000 hours on natural gas fuel at FCE’s facility. The factory cost of the SOFC stack was estimated to be at or below the DOE’s high-volume production cost target (2011 $).

  1. A microdisplay-based HUD for automotive applications: Backplane design, planarization, and optical implementation

    Science.gov (United States)

    Schuck, Miller Harry

    Automotive head-up displays require compact, bright, and inexpensive imaging systems. In this thesis, a compact head-up display (HUD) utilizing liquid-crystal-on-silicon microdisplay technology is presented from concept to implementation. The thesis comprises three primary areas of HUD research: the specification, design and implementation of a compact HUD optical system, the development of a wafer planarization process to enhance reflective device brightness and light immunity and the design, fabrication and testing of an inexpensive 640 x 512 pixel active matrix backplane intended to meet the HUD requirements. The thesis addresses the HUD problem at three levels, the systems level, the device level, and the materials level. At the systems level, the optical design of an automotive HUD must meet several competing requirements, including high image brightness, compact packaging, video-rate performance, and low cost. An optical system design which meets the competing requirements has been developed utilizing a fully-reconfigurable reflective microdisplay. The design consists of two optical stages, the first a projector stage which magnifies the display, and a second stage which forms the virtual image eventually seen by the driver. A key component of the optical system is a diffraction grating/field lens which forms a large viewing eyebox while reducing the optical system complexity. Image quality biocular disparity and luminous efficacy were analyzed and results of the optical implementation are presented. At the device level, the automotive HUD requires a reconfigurable, video-rate, high resolution image source for applications such as navigation and night vision. The design of a 640 x 512 pixel active matrix backplane which meets the requirements of the HUD is described. The backplane was designed to produce digital field sequential color images at video rates utilizing fast switching liquid crystal as the modulation layer. The design methodology is discussed

  2. Two new planar coil designs for a high pressure radio frequency plasma source

    Science.gov (United States)

    Munsat, T.; Hooke, W. M.; Bozeman, S. P.; Washburn, S.

    1995-04-01

    Two planar coil designs for a high pressure rf plasma source are investigated using spectroscopic techniques and circuit analysis. In an Ar plasma a truncated version of the commonly used ``spiral'' coil is found to produce improvements in peak electron density of 20% over the full version. A coil with figure-8 geometry is found to move plasma inhomogeneities off of center and produce electron densities comparable to the spiral coils. Both of these characteristics are advantageous in industrial applications. Coil design characteristics for favorable power coupling are also determined, including the necessity of closed hydrodynamic plasma loops and the drawback of closely situated antiparallel coil currents.

  3. Thermodynamic model and parametric analysis of a tubular SOFC module

    Science.gov (United States)

    Campanari, Stefano

    Solid oxide fuel cells (SOFCs) have been considered in the last years as one of the most promising technologies for very high-efficiency electric energy generation from natural gas, both with simple fuel cell plants and with integrated gas turbine-fuel cell systems. Among the SOFC technologies, tubular SOFC stacks with internal reforming have emerged as one of the most mature technology, with a serious potential for a future commercialization. In this paper, a thermodynamic model of a tubular SOFC stack, with natural gas feeding, internal reforming of hydrocarbons and internal air preheating is proposed. In the first section of the paper, the model is discussed in detail, analyzing its calculating equations and tracing its logical steps; the model is then calibrated on the available data for a recently demonstrated tubular SOFC prototype plant. In the second section of the paper, it is carried out a detailed parametric analysis of the stack working conditions, as a function of the main operating parameters. The discussion of the results of the thermodynamic and parametric analysis yields interesting considerations about partial load SOFC operation and load regulation, and about system design and integration with gas turbine cycles.

  4. Design principles for single standing nanowire solar cells: going beyond the planar efficiency limits.

    Science.gov (United States)

    Zeng, Yang; Ye, Qinghao; Shen, Wenzhong

    2014-05-09

    Semiconductor nanowires (NWs) have long been used in photovoltaic applications but restricted to approaching the fundamental efficiency limits of the planar devices with less material. However, recent researches on standing NWs have started to reveal their potential of surpassing these limits when their unique optical property is utilized in novel manners. Here, we present a theoretical guideline for maximizing the conversion efficiency of a single standing NW cell based on a detailed study of its optical absorption mechanism. Under normal incidence, a standing NW behaves as a dielectric resonator antenna, and its optical cross-section shows its maximum when the lowest hybrid mode (HE11δ) is excited along with the presence of a back-reflector. The promotion of the cell efficiency beyond the planar limits is attributed to two effects: the built-in concentration caused by the enlarged optical cross-section, and the shifting of the absorption front resulted from the excited mode profile. By choosing an optimal NW radius to support the HE11δ mode within the main absorption spectrum, we demonstrate a relative conversion-efficiency enhancement of 33% above the planar cell limit on the exemplary a-Si solar cells. This work has provided a new basis for designing and analyzing standing NW based solar cells.

  5. Planar microlens with front-face angle: design, fabrication, and characterization

    KAUST Repository

    Hafiz, Md Abdullah Al

    2016-07-08

    This paper studies the effect of microlens front-face angle on the performance of an optical system consisting of a planar-graded refractive index (GRIN) lens pair facing each other separated by a free-space region. The planar silica microlens pairs are designed to facilitate low-loss optical signal propagation in the free-space region between the opposing optical waveguides. The planar lens is fabricated from a 38-μm-thick fluorine-doped silica layer on a silicon substrate. It has a parabolic refractive index profile in the vertical direction, which is achieved by controlled fluorine incorporation in the silica film to collimate the optical beam in the vertical direction. Horizontal beam collimation is achieved by incorporating a horizontal curvature at the front face of the lens defined by deep oxide etch. A generalized 3×3ABCDGH transformation matrix method has been derived to compute the coupling efficiency of such microlens pairs to take front-face angles that may be present due to fabrication variations or limitations and possible input/output optical fiber offset/tilt into considerations. Pairs of such planar GRIN lens with various free-space propagation distances between them ranging from 75 to 2500  μm and with front-face angles of 1.5 deg, 2 deg, and 4 deg have been fabricated and characterized. Beam propagation method simulations have been carried out to substantiate the theoretical and experimental results. The results indicate that the optical loss is reasonably low up to 1.5 deg of front-face angles and increases significantly with further increase in the front-face angle. Analysis shows that for a given system with specific microlens front-face angle, the optical loss can be significantly reduced by properly compensating the vertical position of the input and output fibers.

  6. Planar microlens with front-face angle: design, fabrication, and characterization

    Science.gov (United States)

    Al Hafiz, Md. Abdullah; Michael, Aron; Kwok, Chee-Yee

    2016-07-01

    This paper studies the effect of microlens front-face angle on the performance of an optical system consisting of a planar-graded refractive index (GRIN) lens pair facing each other separated by a free-space region. The planar silica microlens pairs are designed to facilitate low-loss optical signal propagation in the free-space region between the opposing optical waveguides. The planar lens is fabricated from a 38-μm-thick fluorine-doped silica layer on a silicon substrate. It has a parabolic refractive index profile in the vertical direction, which is achieved by controlled fluorine incorporation in the silica film to collimate the optical beam in the vertical direction. Horizontal beam collimation is achieved by incorporating a horizontal curvature at the front face of the lens defined by deep oxide etch. A generalized 3×3 ABCDGH transformation matrix method has been derived to compute the coupling efficiency of such microlens pairs to take front-face angles that may be present due to fabrication variations or limitations and possible input/output optical fiber offset/tilt into considerations. Pairs of such planar GRIN lens with various free-space propagation distances between them ranging from 75 to 2500 μm and with front-face angles of 1.5 deg, 2 deg, and 4 deg have been fabricated and characterized. Beam propagation method simulations have been carried out to substantiate the theoretical and experimental results. The results indicate that the optical loss is reasonably low up to 1.5 deg of front-face angles and increases significantly with further increase in the front-face angle. Analysis shows that for a given system with specific microlens front-face angle, the optical loss can be significantly reduced by properly compensating the vertical position of the input and output fibers.

  7. Planar microlens with front-face angle: design, fabrication, and characterization

    KAUST Repository

    Hafiz, Md Abdullah Al; Michael, Aron; Kwok, Chee-Yee

    2016-01-01

    This paper studies the effect of microlens front-face angle on the performance of an optical system consisting of a planar-graded refractive index (GRIN) lens pair facing each other separated by a free-space region. The planar silica microlens pairs are designed to facilitate low-loss optical signal propagation in the free-space region between the opposing optical waveguides. The planar lens is fabricated from a 38-μm-thick fluorine-doped silica layer on a silicon substrate. It has a parabolic refractive index profile in the vertical direction, which is achieved by controlled fluorine incorporation in the silica film to collimate the optical beam in the vertical direction. Horizontal beam collimation is achieved by incorporating a horizontal curvature at the front face of the lens defined by deep oxide etch. A generalized 3×3ABCDGH transformation matrix method has been derived to compute the coupling efficiency of such microlens pairs to take front-face angles that may be present due to fabrication variations or limitations and possible input/output optical fiber offset/tilt into considerations. Pairs of such planar GRIN lens with various free-space propagation distances between them ranging from 75 to 2500  μm and with front-face angles of 1.5 deg, 2 deg, and 4 deg have been fabricated and characterized. Beam propagation method simulations have been carried out to substantiate the theoretical and experimental results. The results indicate that the optical loss is reasonably low up to 1.5 deg of front-face angles and increases significantly with further increase in the front-face angle. Analysis shows that for a given system with specific microlens front-face angle, the optical loss can be significantly reduced by properly compensating the vertical position of the input and output fibers.

  8. On designing low pressure loss working spaces for a planar Stirling micromachine

    Science.gov (United States)

    Hachey, M.-A.; Léveillé, É.; Fréchette, L. G.; Formosa, F.

    2015-12-01

    In this paper, research was undertaken with the objective to design low pressure loss working spaces for a Stirling cycle micro heat engine operating from low temperature waste heat. This planar free-piston heat engine is anticipated to operate at the kHz level with mm3 displacement. Given the resonant nature of the free-piston configuration, the complexity of its working gas’ flow geometry and its projected high operating frequency, flow analysis is relatively complex. Design considerations were thus based on fast prototyping and experimentation. Results show that geometrical features, such as a sharp 90° corner between the regenerator and working spaces, are strong contributors to pressure losses. This research culminated into a promising revised working space configuration for engine start-up, as it considerably reduced total pressure losses, more than 80% at Re = 700, from the original design.

  9. Design and construction of non-imaging planar concentrator for concentrator photovoltaic system

    Energy Technology Data Exchange (ETDEWEB)

    Chong, K.K.; Siaw, F.L.; Wong, C.W.; Wong, G.S. [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Off Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Wilayah Persekutuan (Malaysia)

    2009-05-15

    A novel configuration of solar concentrator, which is the non-imaging planar concentrator, capable of producing much more uniform sunlight and reasonably high concentration ratio, is designed and constructed. This design is envisioned to be incorporated in concentrator photovoltaic (CPV) systems. The work presented here reports on the design, optical alignment and application of the prototype, which is installed at Universiti Tunku Abdul Rahman (UTAR), Malaysia. In the architecture of the prototype, 360 flat mirrors, each with a dimension of 4.0 cm x 4.0 cm, are arranged into 24 rows and 15 columns with a total reflection area of about 5760 cm{sup 2}. In addition to that, illumination distribution for the prototype is simulated and its results are then compared with the experiment result. (author)

  10. Closed-form Solution to Directly Design FACE Waveforms for Beampatterns Using Planar Array

    KAUST Repository

    Bouchoucha, Taha; Ahmed, Sajid; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

    2015-01-01

    In multiple-input multiple-output radar systems, it is usually desirable to steer transmitted power in the region-of-interest. To do this, conventional methods optimize the waveform covariance matrix, R, for the desired beampattern, which is then used to generate actual transmitted waveforms. Both steps require constrained optimization, therefore, use iterative algorithms. The main challenges encountered in the existing approaches are the computational complexity and the design of waveforms to use in practice. In this paper, we provide a closed-form solution to design covariance matrix for the given beampattern using the planar array, which is then used to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope (FACE) waveforms. The proposed algorithm exploits the two-dimensional fast-Fourier-transform. The performance of our proposed algorithm is compared with existing methods that are based on semi-definite quadratic programming with the advantage of a considerably reduced complexity.

  11. Closed-form Solution to Directly Design FACE Waveforms for Beampatterns Using Planar Array

    KAUST Repository

    Bouchoucha, Taha

    2015-04-19

    In multiple-input multiple-output radar systems, it is usually desirable to steer transmitted power in the region-of-interest. To do this, conventional methods optimize the waveform covariance matrix, R, for the desired beampattern, which is then used to generate actual transmitted waveforms. Both steps require constrained optimization, therefore, use iterative algorithms. The main challenges encountered in the existing approaches are the computational complexity and the design of waveforms to use in practice. In this paper, we provide a closed-form solution to design covariance matrix for the given beampattern using the planar array, which is then used to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope (FACE) waveforms. The proposed algorithm exploits the two-dimensional fast-Fourier-transform. The performance of our proposed algorithm is compared with existing methods that are based on semi-definite quadratic programming with the advantage of a considerably reduced complexity.

  12. The design and manufacture of a notch structure for a planar InP Gunn diode

    International Nuclear Information System (INIS)

    Bai Yang; Jia Rui; Wu De-Qi; Jin Zhi; Liu Xin-Yu

    2013-01-01

    A planar InP-based Gunn diode with a notch doping structure is designed and fabricated for integration into millimeter-wave and terahertz integrated circuits. We design two kinds of InP-based Gunn diodes. One has a fixed diameter of cathode area, but has variable spacing between anode and cathode; the other has fixed spacing, but a varying diameter. The threshold voltage and saturated current exhibit their strong dependences on the spacing (10 μm–20 μm) and diameter (40 μm–60 μm) of the InP Gunn diode. The threshold voltage is approximately 4.5 V and the saturated current is in a range of 293 mA–397 mA. In this work, the diameter of the diode and the space between anode and cathode are optimized. The devices are fabricated using a wet etching technique and show excellent performances. The results strongly suggest that low-cost and reliable InP planar Gunn diodes can be used as single chip terahertz sources. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. A spiral, bi-planar gradient coil design for open magnetic resonance imaging.

    Science.gov (United States)

    Zhang, Peng; Shi, Yikai; Wang, Wendong; Wang, Yaohui

    2018-01-01

    To design planar gradient coil for MRI applications without discretization of continuous current density and loop-loop connection errors. In the new design method, the coil current is represented using a spiral curve function described by just a few control parameters. Using a proper parametric equation set, an ensemble of spiral contours is reshaped to satisfy the coil design requirements, such as gradient linearity, inductance and shielding. In the given case study, by using the spiral coil design, the magnetic field errors in the imaging area were reduced from 5.19% (non-spiral design) to 4.47% (spiral design) for the transverse gradient coils, and for the longitudinal gradient coil design, the magnetic field errors were reduced to 5.02% (spiral design). The numerical evaluation shows that when compared with conventional wire loop, the inductance and resistance of spiral coil was reduced by 11.55% and 8.12% for x gradient coil, respectively. A novel spiral gradient coil design for biplanar MRI systems, the new design offers better magnetic field gradients, smooth contours than the conventional connected counterpart, which improves manufacturability.

  14. Operation of real landfill gas fueled solid oxide fuel cell (SOFC) using internal dry reforming

    DEFF Research Database (Denmark)

    Langnickel, Hendrik; Hagen, Anke

    2017-01-01

    Biomass is one renewable energy source, which is independent from solar radiation and wind effect. Solid oxide fuel cells (SOFC’s) are able to convert landfill gas derived from landfill directly into electricity and heat with a high efficiency. In the present work a planar 16cm2 SOFC cell...... was necessary to prevent poisoning and thereby to decrease the degradation rate....

  15. Design and Modeling of Symmetric Three Branch Polymer Planar Optical Power Dividers

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2013-04-01

    Full Text Available Two types of polymer-based three-branch symmetric planar optical power dividers (splitters were designed, multimode interference (MMI splitter and triangular shape-spacing splitter. By means of modeling the real structures were simulated as made of Epoxy Novolak Resin on silicon substrate, with silica buffer layer and polymethylmethacrylate as protection cover layer. The design of polymer waveguide structure was done by Beam Propagation Method. After comparing properties of both types of the splitters we have demonstrated that our new polymer based triangular shaped splitter can work simultaneously in broader spectrum, the only condition would be that the waveguides are single-mode guiding. It practically means that, what concerns communication wavelengths, it can on principle simultaneously operate at two mainly used wavelengths, 1310 and 1550 nm.

  16. Development of conventional and single-chamber planar solid oxide fuel cells by screen-printing; Developpement de piles a combustible de type SOFC, conventionnelles et mono-chambres, en technologie planaire par serigraphie

    Energy Technology Data Exchange (ETDEWEB)

    Rotureau, D.

    2005-06-15

    This work is the first of a new research theme of the laboratory in the field of solid oxide planar fuel cells. With his high experience in the sensor field, the objectives were to realize prototypes using a 'low cost' technology like screen-printing, using classical materials in the field of fuel cells, rather than researching new materials having optimum properties which may be damaged during the realisation of the complete fuel cell. These materials are yttria stabilised zirconia (YSZ) for electrolyte, strontium doped lanthanum manganite (LSM) for cathode and a nickel oxide-YSZ cermet (NiO-YSZ) for anode. The first part of the study consists in structural and electrical characterizations of chosen materials, both on dense pellets and on screen-printed layers of YSZ, LSM or NiO-YSZ. These characterizations showed a good adequation of our materials for a fuel cell application. The second part consists in testing realised prototypes on electrolyte support and on anode support with screen-printed electrodes and electrolyte. The weak obtained performances are mainly due to the low functional temperature (800 C), the thickness of the electrolyte support (about 1 mm) and the porosity of the YSZ screen-printed layers. Finally, we tested in the same time an original device in which both electrodes are exposed to a fuel and air mixture. This promising device inspired from the research on potentiometric sensors developed in the team by N. Guillet (2001), avoids the tightness problem encountered with two gaseous chambers. Moreover, the performances obtained are just twice below than those obtained with a conventional fuel cell with two gaseous chambers. (author)

  17. SOFC Operation with Real Biogas

    DEFF Research Database (Denmark)

    Hagen, Anke; Winiwarter, Anna; Langnickel, Hendrik

    2017-01-01

    Biogas is a valuable energy source and will be available in future in systems relying on renewables. It is an attractive fuel for solid oxide fuel cells (SOFC), which are able to utilize the carbon contained in the biogas and which produce electricity with high efficiency. In the current paper......, state‐of‐the‐art SOFCs were studied regarding performance and durability in relation to biogas as fuel and considering important contaminants, specifically sulfur. First, the catalytic behavior in relevant synthetic biogas mixtures was studied and the potential of dry reforming was demonstrated....... Successful long term operation of an SOFC under both, conditions of steam and dry reforming, i.e., addition of steam or CO2 to avoid carbon formation was shown. For the steam reforming case a remarkable period of 3,500 h, hereof 3,000 h in the presence of H2S was achieved. Finally, a real biogas from...

  18. Numerical simulation and optimal design of Segmented Planar Imaging Detector for Electro-Optical Reconnaissance

    Science.gov (United States)

    Chu, Qiuhui; Shen, Yijie; Yuan, Meng; Gong, Mali

    2017-12-01

    Segmented Planar Imaging Detector for Electro-Optical Reconnaissance (SPIDER) is a cutting-edge electro-optical imaging technology to realize miniaturization and complanation of imaging systems. In this paper, the principle of SPIDER has been numerically demonstrated based on the partially coherent light theory, and a novel concept of adjustable baseline pairing SPIDER system has further been proposed. Based on the results of simulation, it is verified that the imaging quality could be effectively improved by adjusting the Nyquist sampling density, optimizing the baseline pairing method and increasing the spectral channel of demultiplexer. Therefore, an adjustable baseline pairing algorithm is established for further enhancing the image quality, and the optimal design procedure in SPIDER for arbitrary targets is also summarized. The SPIDER system with adjustable baseline pairing method can broaden its application and reduce cost under the same imaging quality.

  19. Design and analysis of planar spiral resonator bandstop filter for microwave frequency

    Science.gov (United States)

    Motakabber, S. M. A.; Shaifudin Suharsono, Muhammad

    2017-11-01

    In microwave frequency, a spiral resonator can act as either frequency reject or acceptor circuits. A planar logarithmic spiral resonator bandstop filter has been developed based on this property. This project focuses on the rejection property of the spiral resonator. The performance analysis of the exhibited filter circuit has been performed by using scattering parameters (S-parameters) technique in the ultra-wideband microwave frequency. The proposed filter is built, simulated and S-parameters analysis have been accomplished by using electromagnetic simulation software CST microwave studio. The commercial microwave substrate Taconic TLX-8 has been used to build this filter. Experimental results showed that the -10 dB rejection bandwidth of the filter is 2.32 GHz and central frequency is 5.72 GHz which is suitable for ultra-wideband applications. The proposed design has been full of good compliance with the simulated and experimental results here.

  20. Optimal design of planar slider-crank mechanism using teaching-learning-based optimization algorithm

    International Nuclear Information System (INIS)

    Chaudhary, Kailash; Chaudhary, Himanshu

    2015-01-01

    In this paper, a two stage optimization technique is presented for optimum design of planar slider-crank mechanism. The slider crank mechanism needs to be dynamically balanced to reduce vibrations and noise in the engine and to improve the vehicle performance. For dynamic balancing, minimization of the shaking force and the shaking moment is achieved by finding optimum mass distribution of crank and connecting rod using the equipemental system of point-masses in the first stage of the optimization. In the second stage, their shapes are synthesized systematically by closed parametric curve, i.e., cubic B-spline curve corresponding to the optimum inertial parameters found in the first stage. The multi-objective optimization problem to minimize both the shaking force and the shaking moment is solved using Teaching-learning-based optimization algorithm (TLBO) and its computational performance is compared with Genetic algorithm (GA).

  1. Optimal design of planar slider-crank mechanism using teaching-learning-based optimization algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, Kailash; Chaudhary, Himanshu [Malaviya National Institute of Technology, Jaipur (Malaysia)

    2015-11-15

    In this paper, a two stage optimization technique is presented for optimum design of planar slider-crank mechanism. The slider crank mechanism needs to be dynamically balanced to reduce vibrations and noise in the engine and to improve the vehicle performance. For dynamic balancing, minimization of the shaking force and the shaking moment is achieved by finding optimum mass distribution of crank and connecting rod using the equipemental system of point-masses in the first stage of the optimization. In the second stage, their shapes are synthesized systematically by closed parametric curve, i.e., cubic B-spline curve corresponding to the optimum inertial parameters found in the first stage. The multi-objective optimization problem to minimize both the shaking force and the shaking moment is solved using Teaching-learning-based optimization algorithm (TLBO) and its computational performance is compared with Genetic algorithm (GA).

  2. Design of Wideband Dual-Polarized Planar Antenna Using Multimode Concept

    Directory of Open Access Journals (Sweden)

    Deqiang Yang

    2016-01-01

    Full Text Available A wideband dual-polarized planar antenna is designed and analyzed by using the theory of characteristic modes (TCM. The eigenvalue, eigencurrent, characteristic pattern, and modal weighting coefficient are analyzed to bring physical insight to this kind of antenna. The results demonstrate that there are two modes resonant in the operating band for each polarization, which have been combined to form a wider frequency band. A bandwidth of 60.2% (1.72–3.2 GHz for VSWR < 1.5 with high isolation of 32 dB is achieved simultaneously. The size of the radiator structure is 0.33λ0 × 0.33λ0 × 0.22λ0 (λ0 refers to the center operating frequency.

  3. Planar Microstrip Ring Resonators for Microwave-Based Gas Sensing: Design Aspects and Initial Transducers for Humidity and Ammonia Sensing.

    Science.gov (United States)

    Bogner, Andreas; Steiner, Carsten; Walter, Stefanie; Kita, Jaroslaw; Hagen, Gunter; Moos, Ralf

    2017-10-24

    A planar microstrip ring resonator structure on alumina was developed using the commercial FEM software COMSOL. Design parameters were evaluated, eventually leading to an optimized design of a miniaturized microwave gas sensor. The sensor was covered with a zeolite film. The device was successfully operated at around 8.5 GHz at room temperature as a humidity sensor. In the next step, an additional planar heater will be included on the reverse side of the resonator structure to allow for testing of gas-sensitive materials under sensor conditions.

  4. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.

    2013-10-06

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  5. In-Operando Raman Characterization of Carbon Deposition on SOFC Anodes

    KAUST Repository

    Maher, R. C.; Duboviks, V.; Offer, G.; Cohen, L. F.; Brandon, N. P.

    2013-01-01

    Carbon formation within nickel-based solid oxide fuel cell (SOFC) anodes exposed to carbonaceous fuels typically leads to reduced operational lifetimes and performance, and can eventually lead to catastrophic failure through cracking and delamination. In-situ Raman spectroscopy has been shown to be a powerful characterization tool for the investigation of the dynamics of physical processes occurring within operational SOFCs in real time. Here we investigate the dynamics of carbon formation on a variety of nickel-based SOFC anodes as a function of temperature, fuel and electrical loading using Raman spectroscopy. We show that the rate of carbon formation throughout the SOFC anode can be significantly reduced through a careful consideration of the SOFC anode material, design and operational conditions. © The Electrochemical Society.

  6. Modeling work of a small scale gasifier/SOFC CHP system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.; Aravind, P.V.; Qu, Z.; Woudstra, N.; Verkooijen, A.H.M. [Delft University of Technology (Netherlands). Dept. of Mechanical Engineering], Emails: ming.liu@tudelft.nl, p.v.aravind@tudelft.nl, z.qu@tudelft.nl, n.woudstra@tudelft.nl, a. h. m. verkooijen@tudelft.nl; Cobas, V.R.M. [Federal University of Itajuba (UNIFEI), Pinheirinhos, MG (Brazil). Dept. of Mechanical Engineering], E-mail: vlad@unifei.edu.br

    2009-07-01

    For a highly efficient biomass gasification/Solid Oxide Fuel Cell (SOFC) Combined Heat and Power (CHP) generation system, the gasifier, the accompanying gas cleaning technologies and the CHP unit must be carefully designed as an integrated unit. This paper describes such a system involving a two-stage fixed-bed down draft gasifier, a SOFC CHP unit and a gas cleaning system. A gas cleaning system with both low temperature and high temperature sections is proposed for coupling the gasifier and the SOFC. Thermodynamic modeling was carried out for the gasifier/SOFC system with the proposed gas cleaning system. The net AC electrical efficiency of this system is around 30% and the overall system efficiency is around 60%. This paper also describes various exergy losses in the system and the future plans for integrated gasifier-GCU-SOFC experiments from which the results will be used to validate the modeling results of this system. (author)

  7. Design of a nanopatterned long focal-length planar focusing collector for concentrated solar power

    Science.gov (United States)

    Ding, Qing; Choubal, Aakash; Toussaint, Kimani C.

    2017-02-01

    Concentrated solar power (CSP) facilities heavily utilize parabolic troughs to collect and concentrate sunlight onto receivers that deliver solar thermal energy to heat engines for generating electricity. However, parabolic troughs are bulky and heavy and result in a large capital investment for CSP plants, thereby making it difficult for CSP technology to be competitive with photovoltaics. We present the design of a planar focusing collector (PFC) with focal length beyond the micron scale. The PFC design is based on the use of a nanostructured silver surface for linearly polarized singlewavelength light. The designed PFC consists of metallic nanogrooves on a dielectric substrate. The geometric properties, namely the width and depth, of a single-unit nanogroove allows for full control of the optical phase at desired spatial coordinates along the nanogroove short-axis for a single wavelength. Moreover, we show numerically that such phase control can be used to construct a phase front that mimics that of a cylindrical lens. In addition, we determine the concentration ratio by comparing the width of our PFC design to the cross-sectional width of its focal spot. We also determine the conversion efficiency at long focal lengths by evaluating the ratio of the collected optical power to the incoming optical power. Finally, we examine the focusing behavior across multiple wavelengths and angles of incidence. Our work shows how nano-optics and plasmonics could contribute to this important area of CSP technology.

  8. Design and investigation of planar technology based ultra-wideband antenna with directional radiation patterns

    Energy Technology Data Exchange (ETDEWEB)

    Meena, M. L., E-mail: madan.meena.ece@gamil.com; Parmar, Girish, E-mail: girish-parmar2002@yahoo.com; Kumar, Mithilesh, E-mail: mith-kr@yahoo.com [Department of Electronics Engineering, Rajasthan Technical University, Kota (India)

    2016-03-09

    A novel design technique based on planar technology for ultra-wideband (UWB) antennas with different ground shape having directional radiation pattern is being presented here. Firstly, the L-shape corner reflector ground plane antenna is designed with microstrip feed line in order to achieve large bandwidth and directivity. Thereafter, for the further improvement in the directivity as well as for better impedance matching the parabolic-shape ground plane has been introduced. The coaxial feed line is given for the proposed directional antenna in order to achieve better impedance matching with 50 ohm transmission line. The simulation analysis of the antenna is done on CST Microwave Studio software using FR-4 substrate having thickness of 1.6 mm and dielectric constant of 4.4. The simulated result shows a good return loss (S11) with respect to -10 dB. The radiation pattern characteristic, angular width, directivity and bandwidth performance of the antenna have also been compared at different resonant frequencies. The designed antennas exhibit low cost, low reflection coefficient and better directivity in the UWB frequency band.

  9. Design of a planar ultra-wideband four-way power divider/combiner using defected ground structures

    DEFF Research Database (Denmark)

    Squartecchia, Michele; Cimoli, Bruno; Midili, Virginio

    2017-01-01

    This work presents the design of a planar ultra-wideband (UWB) four-way power divider/combiner. A prototype has been fabricated on a printed circuit board and characterized. For achieving the frequency response required in UWB applications, each branch of the divider is conceived as a three...

  10. Development of a physically-based planar inductors VHDL-AMS model for integrated power converter design

    Science.gov (United States)

    Ammouri, Aymen; Ben Salah, Walid; Khachroumi, Sofiane; Ben Salah, Tarek; Kourda, Ferid; Morel, Hervé

    2014-05-01

    Design of integrated power converters needs prototype-less approaches. Specific simulations are required for investigation and validation process. Simulation relies on active and passive device models. Models of planar devices, for instance, are still not available in power simulator tools. There is, thus, a specific limitation during the simulation process of integrated power systems. The paper focuses on the development of a physically-based planar inductor model and its validation inside a power converter during transient switching. The planar inductor model remains a complex device to model, particularly when the skin, the proximity and the parasitic capacitances effects are taken into account. Heterogeneous simulation scheme, including circuit and device models, is successfully implemented in VHDL-AMS language and simulated in Simplorer platform. The mixed simulation results has been favorably tested and compared with practical measurements. It is found that the multi-domain simulation results and measurements data are in close agreement.

  11. Direct Closed-Form Design of Finite Alphabet Constant Envelope Waveforms for Planar Array Beampatterns

    KAUST Repository

    Bouchoucha, Taha

    2015-05-01

    Multiple Input Multiple Output (MIMO) radar systems has attracted lately a lot of attention thanks to its advantage over the classical phased array radar systems. We site among these advantages the improvement of parametric identifiability, achievement of higher spatial resolution and design of complex beampatterns. In colocated multiple-input multiple-output radar systems, it is usually desirable to steer transmitted power in the region-of-interest in order to increase the Signal to Noise Ratio (SNR) and reduce any undesired signal and thus improve the detection process. This problem is also known as transmit beampattern design. To achieve this goal, conventional methods optimize the waveform covariance matrix, R, for the desired beampattern, which is then used to generate the actual transmitted waveforms. Both steps require constrained optimization. Most of the existing methods use iterative algorithms to solve these problems, therefore their computational complexity is very high which makes them hard to use in practice especially for real time radar applications. In this paper, we provide a closed-form solution to design the covariance matrix for a given beampattern in the three dimensional space using planar arrays, which is then used to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope waveforms. The proposed algorithm exploits the two-dimensional discrete Fourier transform which is implemented using fast Fourier transform algorithm. Consequently, the computational complexity of the proposed beampattern solution is very low allowing it to be used for large arrays to change the beampattern in real time. We also show that the number of required snapshots in each waveform depends on the beampattern and that it is less than the total number of transmit antennas. In addition, we show that the proposed waveform design method can be used with non symmetric beampatterns. The performance of our proposed algorithm compares

  12. Performance projections and design optimization of planar double gate SOI MOSFETs for logic technology applications

    International Nuclear Information System (INIS)

    Kranti, Abhinav; Hao Ying; Armstrong, G Alastair

    2008-01-01

    In this paper, by investigating the influence of source/drain extension region engineering (also known as gate–source/drain underlap) in nanoscale planar double gate (DG) SOI MOSFETs, we offer new insights into the design of future nanoscale gate-underlap DG devices to achieve ITRS projections for high performance (HP), low standby power (LSTP) and low operating power (LOP) logic technologies. The impact of high-κ gate dielectric, silicon film thickness, together with parameters associated with the lateral source/drain doping profile, is investigated in detail. The results show that spacer width along with lateral straggle can not only effectively control short-channel effects, thus presenting low off-current in a gate underlap device, but can also be optimized to achieve lower intrinsic delay and higher on–off current ratio (I on /I off ). Based on the investigation of on-current (I on ), off-current (I off ), I on /I off , intrinsic delay (τ), energy delay product and static power dissipation, we present design guidelines to select key device parameters to achieve ITRS projections. Using nominal gate lengths for different technologies, as recommended from ITRS specification, optimally designed gate-underlap DG MOSFETs with a spacer-to-straggle (s/σ) ratio of 2.3 for HP/LOP and 3.2 for LSTP logic technologies will meet ITRS projection. However, a relatively narrow range of lateral straggle lying between 7 to 8 nm is recommended. A sensitivity analysis of intrinsic delay, on-current and off-current to important parameters allows a comparative analysis of the various design options and shows that gate workfunction appears to be the most crucial parameter in the design of DG devices for all three technologies. The impact of back gate misalignment on I on , I off and τ is also investigated for optimized underlap devices

  13. Frictional forces in an SOFC stack with sliding seals

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, T; Oishi, N; Namikawa, T; Yamazaki, Y [Tokyo Institute of Technology, Tokyo (Japan)

    1996-06-05

    The detrimental thermal stresses in planar SOFC stacks can be reduced using sliding seals. In the proposal planar stack the electrolyte film is sandwiched by YSZ support rings to release the thermal stresses. In order to estimate the strength of the support ring, the frictional forces between heat resistant alloy and YSZ were measured at 900{degree}C. The coefficient of friction between Hastelloy X and YSZ increased when they were measured lifter 144h heating. However, the coefficient of friction between HA-214 and YSZ did not increase. The measurement and a calculation of the stresses in the support rings led the result that a thickness of 0.6mm was necessary for 200mm diameter support rings under a stack pressure of 0.1kgcm{sup -2}. 6 refs., 9 figs., 1 tab.

  14. A design approach for improving the performance of single-grid planar retarding potential analyzers

    International Nuclear Information System (INIS)

    Davidson, R. L.; Earle, G. D.

    2011-01-01

    Planar retarding potential analyzers (RPAs) have a long flight history and have been included on numerous spaceflight missions including Dynamics Explorer, the Defense Meteorological Satellite Program, and the Communications/Navigation Outage Forecast System. RPAs allow for simultaneous measurement of plasma composition, density, temperature, and the component of the velocity vector normal to the aperture plane. Internal conductive grids are used to approximate ideal potential planes within the instrument, but these grids introduce perturbations to the potential map inside the RPA and cause errors in the measurement of the parameters listed above. A numerical technique is presented herein for minimizing these grid errors for a specific mission by varying the depth and spacing of the grid wires. The example mission selected concentrates on plasma dynamics near the sunset terminator in the equatorial region. The international reference ionosphere model is used to discern the average conditions expected for this mission, and a numerical model of the grid-particle interaction is used to choose a grid design that will best fulfill the mission goals.

  15. Perovskites synthesis to SOFC anodes

    International Nuclear Information System (INIS)

    Wendler, L.P.; Chinelatto, A.L.; Chinelatto, A.S.A.; Ramos, K.

    2012-01-01

    Perovskite structure materials containing lanthanum have been widely applied as solid oxide fuel cells (SOFCs) electrodes, due to its electrical properties. Was investigated the obtain of the perovskite structure LaCr 0,5 Ni 0,5 O 3 , by Pechini method, and its suitability as SOFC anode. The choice of this composition was based on the stability provided by chromium and the catalytic properties of nickel. After preparing the resins, the samples were calcined at 300 deg C, 600 deg C, 700 deg C and 850 deg C. The resulting powders were characterized by X-ray diffraction to determine the existing phases. Furthermore, were performed other analysis, like X-ray fluorescence, He pycnometry, specific surface area by BET isotherm and scanning electronic microscopy (author)

  16. Planar metal-supported SOFC with novel cermet anode

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Hjelm, Johan; Klemensø, Trine

    2011-01-01

    Metal-supported solid oxide fuel cells are expected to offer several potential advantages over conventional anode (Ni-YSZ) supported cells. For example, increased resistance against mechanical and thermal stresses and a reduction in material costs. When Ni-YSZ based anodes are used in metal suppo...

  17. Development of Planar Metal Supported SOFC with Novel Cermet Anode

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Hjelm, Johan; Klemensø, Trine

    2009-01-01

    Metal-supported solid oxide fuel cells are expected to offer several potential advantages over conventional anode (Ni-YSZ) supported cells, such as increased resistance against mechanical and thermal stresses and a reduction in materials cost. When Ni-YSZ based anodes are used in metal supported ...

  18. Slim edge studies, design and quality control of planar ATLAS IBL pixel sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wittig, Tobias

    2013-05-08

    One of the four large experiments at the LHC at CERN is the ATLAS detector, a multi purpose detector. Its pixel detector, composed of three layers, is the innermost part of the tracker. As it is closest to the interaction point, it represents a basic part of the track reconstruction. Besides the requested high resolution one main requirement is the radiation hardness. In the coming years the radiation damage will cause deteriorations of the detector performance. With the planned increase of the luminosity, especially after the upgrade to the High Luminosity LHC, this radiation damage will be even intensified. This circumstance necessitates a new pixel detector featuring improved radiation hard sensors and read-out chips. The present shutdown of the LHC is already utilized to insert an additional b-layer (IBL) into the existing ATLAS pixel detector. The current n-in-n pixel sensor design had to be adapted to the new read-out chip and the module specifications. The new stave geometry requests a reduction of the inactive sensor edge. In a prototype wafer production all modifications have been implemented. The sensor quality control was supervised which led to the decision of the final sensor thickness. In order to evaluate the performance of the sensor chip assemblies with an innovative slim edge design, they have been operated in test beam setups before and after irradiation. Furthermore, the quality control of the planar IBL sensor wafer production was supervised from the stage of wafer delivery to that before the flip chip process to ensure a sufficient amount of functional sensors for the module production.

  19. Study of Internal and External Leaks in Tests of Anode-Supported SOFCs

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hendriksen, Peter Vang; Hagen, Anke

    2008-01-01

    A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass Spectrome......A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass...... Spectrometer were used to detect both internal (through electrolyte) and external (through seals) gas leaks. The internal gas leak through the electrolyte was quantified under different conditions, as was the external leak from the surroundings to the anode. The internal gas leak did not depend on the pressure...... difference between the anode and the cathode gas compartment, and can thus be described as diffusion driven. External leaks between the surroundings and the anode, but not the cathode gas compartment was observed. They were influenced by the pressure difference and are thus driven by both concentration...

  20. Planar array stack design aided by rapid prototyping in development of air-breathing PEMFC

    Science.gov (United States)

    Chen, Chen-Yu; Lai, Wei-Hsiang; Weng, Biing-Jyh; Chuang, Huey-Jan; Hsieh, Ching-Yuan; Kung, Chien-Chih

    The polymer electrolyte membrane fuel cell (PEMFC) is one of the most important research topics in the new and clean energy area. The middle or high power PEMFCs can be applied to the transportation or the distributed power system. But for the small power application, it is needed to match the power requirement of the product generally. On the other hand, the direct methanol fuel cell (DMFC) is one of the most common type that researchers are interested in, but recently the miniature or the micro-PEMFCs attract more attention due to their advantages of high open circuit voltage and high power density. The objective of this study is to develop a new air-breathing planar array fuel cell stacked from 10 cells made by rapid prototyping technology which has potential for fast commercial design, low cost manufacturing, and even without converters/inverters for the system. In this paper, the main material of flow field plates is acrylonitrile-butadiene-styrene (ABS) which allows the fuel cell be mass-manufactured by plastic injection molding technology. The rapid prototyping technology is applied to construct the prototype and verify the practicability of the proposed stack design. A 10-cell air-breathing miniature PEMFC stack with a volume of 6 cm × 6 cm × 0.9 cm is developed and tested. Its segmented membrane electrode assembly (MEA) is designed with the active surface area of 1.3 cm × 1.3 cm in each individual MEA. The platinum loading at anode and cathode are 0.2 mg cm -2 and 0.4 mg cm -2, respectively. Results show that the peak power densities of the parallel connected and serial connected stack are 99 mW cm -2 at 0.425 V and 92 mW cm -2 at 4.25 V, respectively under the conditions of 70 °C relative saturated humidity (i.e., dew point temperature), ambient temperature and free convection air. Besides, the stack performance is increased under forced convection. If the cell surface air is blown by an electric fan, the peak power densities of parallel connected and

  1. Design of a Control System for a Maglev Planar Motor Based on Two-Dimension Linear Interpolation

    Directory of Open Access Journals (Sweden)

    Feng Xing

    2017-08-01

    Full Text Available In order to realize the high speed and high-precision control of a maglev planar motor, a high-precision electromagnetic model is needed in the first place, which can also contribute to meeting the real-time running requirements. Traditionally, the electromagnetic model is based on analytical calculations. However, this neglects the model simplification and the manufacturing errors, which may bring certain errors to the model. Aiming to handle this inaccuracy, this paper proposes a novel design method for a maglev planar motor control system based on two-dimensional linear interpolation. First, the magnetic field is divided into several regions according to the symmetry of the Halbach magnetic array, and the uniform grid method is adopted to partition one of these regions. Second, targeting this region, it is possible to sample the electromagnetic forces and torques on each node of the grid and obtain the complete electromagnetic model in this region through the two-dimensional linear interpolation method. Third, the whole electromagnetic model of the maglev planar motor can be derived according to the symmetry of the magnetic field. Finally, the decoupling method and controller are designed according to this electromagnetic model, and thereafter, the control model can be established. The designed control system is demonstrated through simulations and experiments to feature better accuracy and meet the requirements of real-time control.

  2. Fundamental researches of SOFC in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Demin, A.K.; Neuimin, A.D.; Perfiliev, M.V. [Institute of High Temperatures Electrochemistry, Ekaterinburg (Russian Federation)

    1996-04-01

    The main results of research on ZrO{sub 2}-based solid electrolytes, electrodes and interconnects are reviewed. The mathematical models of the processes in SOFC are considered. Two types of SOFC stacks composed of tubular and block cells, as well the results of their tests are described.

  3. An Efficient Method for Synthesis of Planar Multibody Systems including Shape of Bodies as Design Variables

    DEFF Research Database (Denmark)

    Hansen, Michael R.; Hansen, John Michael

    1998-01-01

    A point contact joint has been developed and implemented in a joint coordinate based planar multibody dynamics analysis program that also supports revolute and translational joints. Further, a segment library for the definition of the contours of the point contact joints has been integrated...

  4. On the optimal design of glass grid shells with planar quadrilateral elements

    DEFF Research Database (Denmark)

    Sassone, Mario; Pugnale, Alberto

    2010-01-01

    specific geometric rules in the grid generation phase but, when the architectural shape is already defined at the conceptual stage, an optimization procedure can yield to suitable configurations. A Relaxation method based on nodal planarity errors and an evolutionary population based Genetic Algorithm have...... been applied to set of benchmarks, in order to tune parameters and to obtain general information about the solution. the problem and their efficiency compared. The Relaxation method in general shows better efficiency in reaching optimal solutions, as an effect of the regularity of the target function......This paper presents an optimization procedure for the solution of the planarity problem, a requirement of grid shells with four or more sides faces that need of having four adjacent nodes laying on a plane in order to use plane glass slabs as cladding elements. It can be satisfied by applying...

  5. Heat and mass transfer analysis intermediate temperature solid oxide fuel cells (IT-SOFC)

    International Nuclear Information System (INIS)

    Timurkutluk, B.; Mat, M. M.; Kaplan, Y.

    2007-01-01

    Solid oxide fuel cells (SOFCs) have been considered as next generation energy conversion system due to their high efficiency, clean and quite operation with fuel flexibility. To date, yittria stabilized zirconia (YSZ) electrolytes have been mainly used for SOFC applications at high temperatures around 1000 degree C because of their high ionic conductivity, chemical stability and good mechanical properties. However, such a high temperature is undesirable for fuel cell operations in the viewpoint of stability. Moreover, high operation temperature necessitates high cost interconnect and seal materials. Thus, the reduction in the operation temperature of SOFCs is one of the key issues in the aspects of the cost reduction and the long term operation without degradation as well as commercialization of the SOFC systems. With the reducing temperature, not only low cost stainless steels and glass materials can be used as interconnect and sealing materials respectively but the manufacturing technology will also extend. Therefore, the design of complex geometrical SOFC component will also be possible. One way to reduce the operation temperature of SOFC is use of an alternative electrolyte material to YSZ showing acceptable properties at intermediate temperatures (600-800 degree C). As being one of IT-SOFC electrolyte materials, gadolinium doped ceria (GDC) has been taken great deals. In this study, a mathematical model for mass and heat transfer for a single cell GDC electrolyte SOFC system was developed and numerical solutions were evaluated. In order to verify the mathematical model, set of experiments were performed by taking species from four different samples randomly and five various temperature measurements. The numerical results reasonably agree with experimental data

  6. Possible Future SOFC - ST Based Power Plants

    OpenAIRE

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    Hybrid systems consisting Solid Oxide Fuel Cell (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas. A desulfurization reactor removes the sulfur content in the NG while a pre-reformer break down the heavier hydrocarbons. The pre-treated fuel enters then into the anode side of the SOFC. The gases from the SOFC stacks enter into a burner to burn the rest of the fuel. The off-gases now enter into a heat recovery steam generator to produce steam for a ...

  7. A planar waveguide optical discrete Fourier transformer design for 160 Gb/s all-optical OFDM systems

    Science.gov (United States)

    Li, Wei; Liang, Xiaojun; Ma, Weidong; Zhou, Tianhong; Huang, Benxiong; Liu, Deming

    2010-01-01

    A cost-effective all-optical discrete Fourier transformer (ODFT) is designed based on a silicon planar lightwave circuit (PLC), which can be applied to all-optical orthogonal frequency division multiplexing (OFDM) transmission systems and can be achieved by current techniques. It consists of 2 × 2 directional couplers, phase shifters and optical delay lines. Metal-film heaters are used as phase shifters, according to the thermooptic effect of SiO 2. Based on the ODFT, a 160 Gb/s OFDM system is set up. Simulation results show excellent bit error rate (BER) and optical signal-to-noise ratio (OSNR) performances after 400 km transmission.

  8. SOFC regulation at constant temperature: Experimental test and data regression study

    International Nuclear Information System (INIS)

    Barelli, L.; Bidini, G.; Cinti, G.; Ottaviano, A.

    2016-01-01

    Highlights: • SOFC operating temperature impacts strongly on its performance and lifetime. • Experimental tests were carried out varying electric load and feeding mixture gas. • Three different anodic inlet gases were tested maintaining constant temperature. • Cathodic air flow rate was used to maintain constant its operating temperature. • Regression law was defined from experimental data to regulate the air flow rate. - Abstract: The operating temperature of solid oxide fuel cell stack (SOFC) is an important parameter to be controlled, which impacts the SOFC performance and its lifetime. Rapid temperature change implies a significant temperature differences between the surface and the mean body leading to a state of thermal shock. Thermal shock and thermal cycling introduce stress in a material due to temperature differences between the surface and the interior, or between different regions of the cell. In this context, in order to determine a control law that permit to maintain constant the fuel cell temperature varying the electrical load and the infeed fuel mixture, an experimental activity were carried out on a planar SOFC short stack to analyse stack temperature. Specifically, three different anodic inlet gas compositions were tested: pure hydrogen, reformed natural gas with steam to carbon ratio equal to 2 and 2.5. By processing the obtained results, a regression law was defined to regulate the air flow rate to be provided to the fuel cell to maintain constant its operating temperature varying its operating conditions.

  9. Development of Residential SOFC Cogeneration System

    Science.gov (United States)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-06-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the "Demonstrative Research on Solid Oxide Fuel Cells" Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  10. Development of Residential SOFC Cogeneration System

    International Nuclear Information System (INIS)

    Ono, Takashi; Miyachi, Itaru; Suzuki, Minoru; Higaki, Katsuki

    2011-01-01

    Since 2001 Kyocera has been developing 1kW class Solid Oxide Fuel Cell (SOFC) for power generation system. We have developed a cell, stack, module and system. Since 2004, Kyocera and Osaka Gas Co., Ltd. have been developed SOFC residential co-generation system. From 2007, we took part in the 'Demonstrative Research on Solid Oxide Fuel Cells' Project conducted by New Energy Foundation (NEF). Total 57 units of 0.7kW class SOFC cogeneration systems had been installed at residential houses. In spite of residential small power demand, the actual electric efficiency was about 40%(netAC,LHV), and high CO2 reduction performance was achieved by these systems. Hereafter, new joint development, Osaka Gas, Toyota Motors, Kyocera and Aisin Seiki, aims early commercialization of residential SOFC CHP system.

  11. Printable Fabrication of Nanocoral-Structured Electrodes for High-Performance Flexible and Planar Supercapacitor with Artistic Design.

    Science.gov (United States)

    Lin, Yuanjing; Gao, Yuan; Fan, Zhiyong

    2017-11-01

    Planar supercapacitors with high flexibility, desirable operation safety, and high performance are considered as attractive candidates to serve as energy-storage devices for portable and wearable electronics. Here, a scalable and printable technique is adopted to construct novel and unique hierarchical nanocoral structures as the interdigitated electrodes on flexible substrates. The as-fabricated flexible all-solid-state planar supercapacitors with nanocoral structures achieve areal capacitance up to 52.9 mF cm -2 , which is 2.5 times that of devices without nanocoral structures, and this figure-of-merit is among the highest in the literature for the same category of devices. More interestingly, due to utilization of the inkjet-printing technique, excellent versatility on electrode-pattern artistic design is achieved. Particularly, working supercapacitors with artistically designed patterns are demonstrated. Meanwhile, the high scalability of such a printable method is also demonstrated by fabrication of large-sized artistic supercapacitors serving as energy-storage devices in a wearable self-powered system as a proof of concept. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. LG Solid Oxide Fuel Cell (SOFC) Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Haberman, Ben [LG Fuel Cell Systems Inc., North Canton, OH (United States); Martinez-Baca, Carlos [LG Fuel Cell Systems Inc., North Canton, OH (United States); Rush, Greg [LG Fuel Cell Systems Inc., North Canton, OH (United States)

    2013-05-31

    This report presents a summary of the work performed by LG Fuel Cell Systems Inc. during the project LG Solid Oxide Fuel Cell (SOFC) Model Development (DOE Award Number: DE-FE0000773) which commenced on October 1, 2009 and was completed on March 31, 2013. The aim of this project is for LG Fuel Cell Systems Inc. (formerly known as Rolls-Royce Fuel Cell Systems (US) Inc.) (LGFCS) to develop a multi-physics solid oxide fuel cell (SOFC) computer code (MPC) for performance calculations of the LGFCS fuel cell structure to support fuel cell product design and development. A summary of the initial stages of the project is provided which describes the MPC requirements that were developed and the selection of a candidate code, STAR-CCM+ (CD-adapco). This is followed by a detailed description of the subsequent work program including code enhancement and model verification and validation activities. Details of the code enhancements that were implemented to facilitate MPC SOFC simulations are provided along with a description of the models that were built using the MPC and validated against experimental data. The modeling work described in this report represents a level of calculation detail that has not been previously available within LGFCS.

  13. A Novel Multiband Miniature Planar Inverted F Antenna Design for Bluetooth and WLAN Applications

    Directory of Open Access Journals (Sweden)

    J. M. Jeevani W. Jayasinghe

    2015-01-01

    Full Text Available A novel compact planar inverted F antenna (PIFA optimized using genetic algorithms for 2.4 GHz (Bluetooth and 5 GHz (UNII-1, UNII-2, UNII-2 extended, and UNII-3 bands is presented. The patch with a shorting pin is on a 20×7×0.762 mm3 substrate, which is suspended in air 5 mm above a 30×7 mm2 ground plane. Genetic algorithm optimization (GAO is used to optimize the patch geometry, feed position, and shorting pin position simultaneously. Simulations are carried out by using HFSS and a prototype antenna is fabricated to compare the measurements with the simulations. The antenna shows fractional impedance bandwidths of 4% and 21% and gains of 2.5 dB and 3.2 dB at lower and upper bands, respectively.

  14. Development of a solid oxide fuel cell (SOFC) automotive auxiliary power unit (APU) fueled by gasoline

    International Nuclear Information System (INIS)

    DeMinco, C.; Mukerjee, S.; Grieve, J.; Faville, M.; Noetzel, J.; Perry, M.; Horvath, A.; Prediger, D.; Pastula, M.; Boersma, R.; Ghosh, D.

    2000-01-01

    This paper describes the design and the development progress of a 3 to 5 auxiliary power unit (APU) based on a gasoline fueled solid oxide fuel cell (SOFC). This fuel cell was supplied reformate gas (reactant) by a partial oxidation (POx) catalytic reformer utilizing liquid gasoline and designed by Delphi Automotive Systems. This reformate gas consists mainly of hydrogen, carbon monoxide and nitrogen and was fed directly in to the SOFC stack without any additional fuel reformer processing. The SOFC stack was developed by Global Thermoelectric and operates around 700 o C. This automotive APU produces power to support future 42 volt vehicle electrical architectures and loads. The balance of the APU, designed by Delphi Automotive Systems, employs a packaging and insulation design to facilitate installation and operation on-board automobiles. (author)

  15. The integrated project SOFC600 development of low-temperature SOFC

    DEFF Research Database (Denmark)

    Rietveld, B.; Van Berkel, F.; Zhang-Steenwinkel, Y.

    2009-01-01

    The Integrated Project SOFC600 unites 21 partners jointly working on the research and development of SOFC stack components for operation at 600oC. The project is funded by the European Commission within the 6th Framework Programme. Low-temperature operation is considered essential for achieving c...

  16. Analysis And Simulation Of Low Profile Planar Inverted - F Antenna Design For WLAN Operation In Portable Devices

    Directory of Open Access Journals (Sweden)

    Zaw Htet Lwin

    2015-08-01

    Full Text Available This paper presents a compact planar invertedF antenna PIFA design for WLAN operation in portable devices. The proposed design has size of 8 x 21 mm and provides peak directive gain of 5.78dBi with the peak return loss of -33.89dB and input impedance of 50.28amp8486. It covers a 10dB return loss bandwidth of 410MHz 2.37GHz 2.789GHz. Its VSWR varies from 1.96 to 1.93 within the antenna return loss bandwidth. As the dimension of the proposed antenna is very small the antenna is promising to be embedded within the different portable devices employing WiFi applications. This paper includes the return loss as a function of frequency with varying the different parameters VSWR input resistance radiation pattern and current distribution of the proposed antenna.

  17. Planar ESPAR Array Design with Nonsymmetrical Pattern by Means of Finite-Element Method, Domain Decomposition, and Spherical Wave Expansion

    Directory of Open Access Journals (Sweden)

    Jesús García

    2012-01-01

    Full Text Available The application of a 3D domain decomposition finite-element and spherical mode expansion for the design of planar ESPAR (electronically steerable passive array radiator made with probe-fed circular microstrip patches is presented in this work. A global generalized scattering matrix (GSM in terms of spherical modes is obtained analytically from the GSM of the isolated patches by using rotation and translation properties of spherical waves. The whole behaviour of the array is characterized including all the mutual coupling effects between its elements. This procedure has been firstly validated by analyzing an array of monopoles on a ground plane, and then it has been applied to synthesize a prescribed radiation pattern optimizing the reactive loads connected to the feeding ports of the array of circular patches by means of a genetic algorithm.

  18. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G., E-mail: dgr@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas, Habana (Cuba). Dept. de Ingenieria Nuclear; Lira, Carlos A.B.O., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2013-07-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  19. Analysis and optimization of a tubular SOFC, using nuclear hydrogen as fuel

    International Nuclear Information System (INIS)

    Rodriguez, Daniel G.; Parra, Lazaro R.G.; Fernandez, Carlos R.G.; Lira, Carlos A.B.O.

    2013-01-01

    One of the main areas of hydrogen uses as an energy carrier is in fuel cells of high standards as solid oxide fuel cells (SOFC). The SOFCs are fuel cells operate at high temperatures making them ideal for use in large power systems, suitable for distributed generation of electricity. Optimization and analysis of these electrochemical devices is an area of great current study. The computational fluid dynamics software (CFD) have unique advantages for analyzing the influence of design parameters on the efficiency of fuel cells. This paper presents a SOFC design cell which employ as fuel hydrogen produced by thermochemical water splitting cycle (I-S). There will be done the optimization of the main parameters thermodynamic and electrochemical cell operating to achieve top performance. Also will be estimate the cell efficiency and a production-consumption hydrogen system. (author)

  20. Two-Stage Design Method for Enhanced Inductive Energy Transmission with Q-Constrained Planar Square Loops.

    Directory of Open Access Journals (Sweden)

    Akaa Agbaeze Eteng

    Full Text Available Q-factor constraints are usually imposed on conductor loops employed as proximity range High Frequency Radio Frequency Identification (HF-RFID reader antennas to ensure adequate data bandwidth. However, pairing such low Q-factor loops in inductive energy transmission links restricts the link transmission performance. The contribution of this paper is to assess the improvement that is reached with a two-stage design method, concerning the transmission performance of a planar square loop relative to an initial design, without compromise to a Q-factor constraint. The first stage of the synthesis flow is analytical in approach, and determines the number and spacing of turns by which coupling between similar paired square loops can be enhanced with low deviation from the Q-factor limit presented by an initial design. The second stage applies full-wave electromagnetic simulations to determine more appropriate turn spacing and widths to match the Q-factor constraint, and achieve improved coupling relative to the initial design. Evaluating the design method in a test scenario yielded a more than 5% increase in link transmission efficiency, as well as an improvement in the link fractional bandwidth by more than 3%, without violating the loop Q-factor limit. These transmission performance enhancements are indicative of a potential for modifying proximity HF-RFID reader antennas for efficient inductive energy transfer and data telemetry links.

  1. Structural design considerations for micromachined solid-oxide fuel cells

    Science.gov (United States)

    Srikar, V. T.; Turner, Kevin T.; Andrew Ie, Tze Yung; Spearing, S. Mark

    Micromachined solid-oxide fuel cells (μSOFCs) are among a class of devices being investigated for portable power generation. Optimization of the performance and reliability of such devices requires robust, scale-dependent, design methodologies. In this first analysis, we consider the structural design of planar, electrolyte-supported, μSOFCs from the viewpoints of electrochemical performance, mechanical stability and reliability, and thermal behavior. The effect of electrolyte thickness on fuel cell performance is evaluated using a simple analytical model. Design diagrams that account explicitly for thermal and intrinsic residual stresses are presented to identify geometries that are resistant to fracture and buckling. Analysis of energy loss due to in-plane heat conduction highlights the importance of efficient thermal isolation in microscale fuel cell design.

  2. Thermodynamic analysis of SOFC (solid oxide fuel cell)–Stirling hybrid plants using alternative fuels

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated. Simulations of the proposed system were conducted using different fuels, which should facilitate the use of a variety of fuels depending on availability. Here, the results for natural gas (NG), ammonia, di-methyl ether (DME), methanol and ethanol are presented and analyzed. The system behavior is further investigated by comparing the effects of key factors, such as the utilization factor and the operating conditions under which these fuels are used. Moreover, the effect of using a methanator on the plant efficiency is also studied. The combined system improves the overall electrical efficiency relative to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes. Additionally, heat is also produced to heat the family home when necessary. - Highlights: • Integrating a solid oxide fuel with a Stirling engine • Design of multi-fuel hybrid plants • Plants running on alternative fuels; natural gas, methanol, ethanol, DME and ammonia • Thermodynamic analysis of hybrid SOFC–Stirling engine plants

  3. Recent Development of SOFC Metallic Interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Wu JW, Liu XB

    2010-04-01

    Interest in solid oxide fuel cells (SOFC) stems from their higher e±ciencies and lower levels of emitted pollu- tants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i:e:, to maintain high elec- trical conductivity, good stability in both reducing and oxidizing atmospheres, and close coe±cient of thermal expansion (CTE) match and good compatibility with other SOFC ceramic components. The paper reviewed the interconnect materials, and coatings for metallic interconnect materials.

  4. Ceramic materials for SOFCs: Current status

    Directory of Open Access Journals (Sweden)

    Kozhukharov, V.

    2002-10-01

    Full Text Available It is well known that the main parts of Solid Oxide Fuel Cells (SOFCs are build from ceramic materials. Namely the ceramic materials and composites, used for SOFCs manufacturing, are objects of the overview in the present work. The analysis carried out covers the last current publications in the field discussed. Special attention and examination in details have been done on patents state-of-the-art. After a background and short classification of the ceramic SOFCs materials the attention is focused on cathode, electrolyte, anode, interconnection and sealing materials. Their requirements, structure, thermal stability, composition control and behavior, processing and performance are the object of overview. A correlation has been made between the phase diagrams oxygen incorporation and transport, and SOFC advantages, generally for materials of lanthanum- base perovskite family. In order to analyze the innovative investigations regarding the patent branch of the SOFCs development and application, an object of review was patents from Japan, USA, Germany and European Union. Some examples of the inventions with accent on the ceramic materials are shown. In addition the tendency regarding R & D activities of SOFCs development materials from the leading companies in the world is analyzed. On the base of the most important technological and economical parameters of cell cathode/electrolyte/anode materials an attempt for evaluation and correlation has been made and innovative conceptions are shown.

    Es bien sabido que los componentes principales de las celdas de combustible de óxido sólido (SOFCs estan constituidos por materiales cerámicos. Dichos materiales cerámicos y materiales compuestos que se utilizan en la fabricación de SOFCs son objeto de estudio en el presente trabajo. El análisis llevado a cabo incluye la revisión de las últimas publicaciones en la materia, con una especial atención y examen minucioso sobre las patentes m

  5. Study on dynamic performance of SOFC

    Science.gov (United States)

    Zhan, Haiyang; Liang, Qianchao; Wen, Qiang; Zhu, Runkai

    2017-05-01

    In order to solve the problem of real-time matching of load and fuel cell power, it is urgent to study the dynamic response process of SOFC in the case of load mutation. The mathematical model of SOFC is constructed, and its performance is simulated. The model consider the influence factors such as polarization effect, ohmic loss. It also takes the diffusion effect, thermal effect, energy exchange, mass conservation, momentum conservation. One dimensional dynamic mathematical model of SOFC is constructed by using distributed lumped parameter method. The simulation results show that the I-V characteristic curves are in good agreement with the experimental data, and the accuracy of the model is verified. The voltage response curve, power response curve and the efficiency curve are obtained by this way. It lays a solid foundation for the research of dynamic performance and optimal control in power generation system of high power fuel cell stack.

  6. Material orientation design of planar structures with prescribed anisotropy classes. Study of rhombic systems

    Science.gov (United States)

    Czubacki, Radosław

    2018-01-01

    The paper deals with the minimum compliance problem of 2D structures made of a non-homogeneous elastic material. In the first part of the paper a comparison between solutions of Free Material Design (FMD), Cubic Material Design (CMD) and Isotropic Material Design (IMD) is shown for a simply supported plate in a shape of a deep beam, subjected to a concentrated in-plane force at its upper face. The isoperimetric condition fixes the value of the cost of the design expressed as the integral of the trace of the Hooke tensor. In the second part of the paper the material design approaches are extended to rhombic system in 2D. For the rhombic system the material properties of the structures are set, the design variables being the trajectories of anisotropy directions which in 2D are described by one parameter. In the Orthotropic Orientation Design (OOD) no isoperimetric condition is used.

  7. High Performance Infiltrated Backbones for Cathode-Supported SOFC's

    DEFF Research Database (Denmark)

    Gil, Vanesa; Kammer Hansen, Kent

    2014-01-01

    The concept of using highly ionic conducting backbones with subsequent infiltration of electronically conducting particles has widely been used to develop alternative anode-supported SOFC's. In this work, the idea was to develop infiltrated backbones as an alternative design based on cathode......, microstructural characterization and electrochemical testing are discussed. Data on polarization resistance, Rp, are obtained from impedance spectra recorded on quasi-symmetrical cells (YSZ backbones/YSZ/LSM-YSZ (screen printed)). The backbones are infiltrated with LSM and compared to a standard LSM-YSZ screen...

  8. Development of Long-Term Stable and High-Performing Metal-Supported SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Nielsen, Jimmi; Blennow Tullmar, Peter

    2011-01-01

    Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating temperat......Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating...... temperatures, while retaining both the energy output and the stability. The metal-supported SOFC design developed at Risø DTU has been optimized to an ASR value of 0.62 cm2 at 650 °C, and a steady degradation rate of 1.0% kh-1 demonstrated for 3000 h on a 16 cm2 active cell level. Additional improvement...

  9. Performance and life time test on a 5 kW SOFC system for distributed cogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Rosa; De Biase, Sabrina; Ginocchio, Stefano [Edison S.p.A, Via Giorgio La Pira, 2, 10028 Trofarello (Italy); Bedogni, Stefano; Montelatici, Lorenzo [Edison S.p.A, Foro Bonaparte 31, 20121 Milano (Italy)

    2008-06-15

    Edison R and D Centre is committed to test a wide range of commercial and prototypal fuel cell systems. The activities aim to evaluate the available state of the art of these technologies and their maturity for the relevant market. The laboratory is equipped with ad hoc test benches designed to study single cells, stacks and systems. The characterization of commercial and new generation PEMFC, also for high temperatures (160 C), together with the analysis of the behaviour of SOFC represent the core activities of the laboratory. On January 2007 a new 5 kW SOFC system supplied by Acumentrics was installed. The claimed electrical power output is 5 kW and thermal power is 3 kW. The aim of the test is the achievement of technical and economical assessment for future applications of small SOFC plants for distributed cogeneration. Performance and life time test of the system are shown. (author)

  10. Planar solid oxide fuel cells: the Australian experience and outlook

    Science.gov (United States)

    Godfrey, Bruce; Föger, Karl; Gillespie, Rohan; Bolden, Roger; Badwal, S. P. S.

    Since 1992, Ceramic Fuel Cells (CFCL) has grown to what is now the largest focussed program globally for development of planar ceramic (solid oxide) fuel cell, SOFC, technology. A significant intellectual property position in know-how and patents has been developed, with over 80 people involved in the venture. Over $A60 million in funding for the activities of the company has been raised from private companies, government-owned corporations and government business-support programs, including from energy — particularly electricity — industry shareholders that can facilitate access to local markets for our products. CFCL has established state-of-the-art facilities for planar SOFC R&D, with their expansion and scaling-up to pilot manufacturing capability underway. We expect to achieve commercial introduction of our market-entry products in 2002, with prototype systems expected to be available from early 2001.

  11. Design and TCAD simulation of planar p-on-n active-edge pixel sensors for the next generation of FELs

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Betta, G.-F., E-mail: gianfranco.dallabetta@unitn.it [Università di Trento, Dipartimento di Ingegneria Industriale, I-38123 Trento (Italy); TIFPA INFN, I-38123 Trento (Italy); Batignani, G. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Benkechkache, M.A. [TIFPA INFN, I-38123 Trento (Italy); University Constantine 1, Department of Electronics in the Science and Technology Faculty, I-25017 Constantine (Algeria); Bettarini, S.; Casarosa, G. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Comotti, D. [Università di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Fabris, L. [INFN Sezione di Pavia, I-27100 Pavia (Italy); Università di Bergamo, Dipartimento di Ingegneria e Scienze Applicate, I-24044 Dalmine (Italy); Forti, F. [Università di Pisa, Dipartimento di Fisica, I-56127 Pisa (Italy); INFN, Sezione di Pisa, I-56127 Pisa (Italy); Grassi, M. [Università di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Latreche, S. [University Constantine 1, Department of Electronics in the Science and Technology Faculty, I-25017 Constantine (Algeria); Lodola, L.; Malcovati, P. [Università di Pavia, Dipartimento di Ingegneria Industriale e dell' Informazione, I-27100 Pavia (Italy); INFN Sezione di Pavia, I-27100 Pavia (Italy); Manghisoni, M. [INFN Sezione di Pavia, I-27100 Pavia (Italy); Università di Bergamo, Dipartimento di Ingegneria e Scienze Applicate, I-24044 Dalmine (Italy); and others

    2016-07-11

    We report on the design and TCAD simulations of planar p-on-n sensors with active edge aimed at a four-side buttable X-ray detector module for future FEL applications. Edge terminations with different number of guard rings were designed to find the best trade-off between breakdown voltage and border gap size. The methodology of the sensor design, the optimization of the most relevant parameters to maximize the breakdown voltage and the final layout are described.

  12. Design and TCAD simulation of planar p-on-n active-edge pixel sensors for the next generation of FELs

    International Nuclear Information System (INIS)

    Dalla Betta, G.-F.; Batignani, G.; Benkechkache, M.A.; Bettarini, S.; Casarosa, G.; Comotti, D.; Fabris, L.; Forti, F.; Grassi, M.; Latreche, S.; Lodola, L.; Malcovati, P.; Manghisoni, M.

    2016-01-01

    We report on the design and TCAD simulations of planar p-on-n sensors with active edge aimed at a four-side buttable X-ray detector module for future FEL applications. Edge terminations with different number of guard rings were designed to find the best trade-off between breakdown voltage and border gap size. The methodology of the sensor design, the optimization of the most relevant parameters to maximize the breakdown voltage and the final layout are described.

  13. Comparison of the Degradation of the Polarization Resistance of Symmetrical LSM-YSZ Cells, with Anode Supported Ni-YSZ/YSZ/LSM-YSZ SOFCs

    DEFF Research Database (Denmark)

    Torres da Silva, Iris Maura; Nielsen, Jimmi; Hjelm, Johan

    2009-01-01

    Impedance spectra of a symmetrical cell with SOFC cathodes (LSM-YSZ/YSZ/LSM-YSZ) and an anode supported planar SOFC (Ni-YSZ/YSZ/LSM-YSZ) were collected at OCV at 650{degree sign}C in air (cathode) and humidified (4%) hydrogen (anode), over 155 hours. The impedance was affected by degradation over...... time in the same frequency range for both cells (~10 Hz), possibly indicating that the same physical process was affected in both types of cell. However, deconvolution of the impedance data was not straightforward. When n-values of the constant phase elements in the otherwise identical equivalent...

  14. Solid oxide fuel cell (SOFC) materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Developing materials for SOFC applications is one of the key topics in energy research. The book focuses on manganite structured materials, such as doped lanthanum chromites and lanthanum manganites, which have interesting properties: thermal and chemical stability, mixed ionic and electrical conductivity, electrocatalytic activity, magnetocaloric property and colossal magnetoresistance (CMR).

  15. Possible Future SOFC - ST Based Power Plants

    DEFF Research Database (Denmark)

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    Hybrid systems consisting Solid Oxide Fuel Cell (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas. A desulfurization reactor removes the sulfur content in the NG while a pre-reformer break down the heavier hydrocarbons. The pre-treated fuel enters...

  16. Interfacial layers in tape cast anode-supported doped lanthanum gallate SOFC elements

    Energy Technology Data Exchange (ETDEWEB)

    Maffei, N.; De Silveira, G. [Materials Technology Laboratory, Natural Resources Canada, CANMET, 405 Rochester Street, Ottawa, Ontario (Canada) K1A OG3

    2003-04-01

    Lanthanum gallate doped with strontium and magnesium (LSGM) is a promising electrolyte system for intermediate temperature solid oxide fuel cells (SOFCs). The reported formation of interfacial layers in monolithic type SOFCs based on lanthanum gallate is of concern because of its impact on the performance of the fuel cell. Planar anode-supported SOFC elements (without the cathode) were prepared by the tape casting technique in order to determine the nature of the anode/electrolyte interface after sintering. Two anode systems were studied, one a NiO-CeO{sub 2} cermet, and the other, a modified lanthanum gallate anode containing manganese. Sintering studies were conducted at 1250, 1300, 1350, 1400 and 1450 C to determine the effect of temperature on the interfacial characteristics. Scanning electron microscopy (SEM) revealed a significant diffusion of Ni from the NiO-CeO{sub 2} anode resulting in the formation of an interfacial layer regardless of sintering temperature. Significant La diffusion from the electrolyte into the anode was also observed. In the case of the modified lanthanum gallate anode containing manganese, there was no interfacial layer formation, but a significant diffusion of Mn into the electrolyte was observed.

  17. Design and simulation of a planar micro-optic free-space receiver

    Science.gov (United States)

    Nadler, Brett R.; Hallas, Justin M.; Karp, Jason H.; Ford, Joseph E.

    2017-11-01

    We propose a compact directional optical receiver for free-space communications, where a microlens array and micro-optic structures selectively couple light from a narrow incidence angle into a thin slab waveguide and then to an edge-mounted detector. A small lateral translation of the lenslet array controls the coupled input angle, enabling the receiver to select the transmitter source direction. We present the optical design and simulation of a 10mm x 10mm aperture receiver using a 30μm thick silicon waveguide able to couple up to 2.5Gbps modulated input to a 10mm x 30μm wide detector.

  18. Liquid-fueled SOFC power sources for transportation

    Science.gov (United States)

    Myles, K. M.; Doshi, R.; Kumar, R.; Krumpelt, M.

    Traditionally, fuel cells have been developed for space or stationary terrestrial applications. As the first commercial 200-kW systems were being introduced by ONSI and Fuji Electric, the potentially much larger, but also more challenging, application in transportation was beginning to be addressed. As a result, fuel cell-powered buses have been designed and built, and R&D programs for fuel cell-powered passenger cars have been initiated. The engineering challenge of eventually replacing the internal combustion engine in buses, trucks, and passenger cars with fuel cell systems is to achieve much higher power densities and much lower costs than obtainable in systems designed for stationary applications. At present, the leading fuel cell candidate for transportation applications is, without question, the polymer electrolyte fuel cell (PEFC). Offering ambient temperature start-up and the potential for a relatively high power density, the polymer technology has attracted the interest of automotive manufacturers worldwide. But the difficulties of fuel handling for the PEFC have led to a growing interest in exploring the prospects for solid oxide fuel cells (SOFCs) operating on liquid fuels for transportation applications. Solid oxide fuel cells are much more compatible with liquid fuels (methanol or other hydrocarbons) and are potentially capable of power densities high enough for vehicular use. Two SOFC options for such use are discussed in this report.

  19. Design and analysis of a 3-DOF planar micromanipulation stage with large rotational displacement for micromanipulation system

    Directory of Open Access Journals (Sweden)

    B. Ding

    2017-05-01

    Full Text Available Flexure-based mechanisms have been widely used for scanning tunneling microscopy, nanoimprint lithography, fast servo tool system and micro/nano manipulation. In this paper, a novel planar micromanipulation stage with large rotational displacement is proposed. The designed monolithic manipulator has three degrees of freedom (DOF, i.e. two translations along the X and Y axes and one rotation around Z axis. In order to get a large workspace, the lever mechanism is adopted to magnify the stroke of the piezoelectric actuators and also the leaf beam flexure is utilized due to its large rotational scope. Different from conventional pre-tightening mechanism, a modified pre-tightening mechanism, which is less harmful to the stacked actuators, is proposed in this paper. Taking the circular flexure hinges and leaf beam flexures hinges as revolute joints, the forward kinematics and inverse kinematics models of this stage are derived. The workspace of the micromanipulator is finally obtained, which is based on the derived kinematic models.

  20. Modelling and design of planar Hall effect bridge sensors for low-frequency applications

    DEFF Research Database (Denmark)

    Persson, Åsa; Bejhed, R.S.; Østerberg, Frederik Westergaard

    2013-01-01

    .g., disregarding shape anisotropy effects, and also incorporates some approximations. To validate the results, modelled data was compared to measurements on actual PHEBs and was found to predict the measured values within 13% for the investigated geometries. Subsequently, the model was used to establish a design...... that PHEBs can be applicable to several different areas within science including satellite attitude determination and magnetic bead detection in lab-on-a-chip applications, where detectivities down towards 1 nT Hz -0.5 at 1 Hz are required, and maybe even magnetic field measurements in scientific space......The applicability of miniaturized magnetic field sensors is being explored in several areas of magnetic field detection due to their integratability, low mass, and potentially low cost. In this respect, different thin-film technologies, especially those employing magnetoresistance, show great...

  1. Investigation of new materials for SOFC applications; Untersuchungen zum Einsatz neuer Werkstoffe fuer SOFC-Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Wackerl, J.

    2007-05-04

    Fuel cells based on solid oxides ('SOFC') are excellent alternative devices for power generation, when they are operated at high temperature, e.g. above 600 C. Having only fixed parts for the power generating part of the device is only one advantage of the fuel cell. Due to their unique design, these devices offer a maximum of efficiency for energy conversion compared to conventional power generating systems, which are mainly based on turbines. One aim of this thesis is the examination of alternative electrolyte and cathode materials for the SOFC applications at reduced temperatures, which means in the temperature range between 600 C and 750 C. For the first main task, several materials from the oxygen ion conducting electrolytes were selected. Different strontium and magnesium doped lanthanum gallate (LSGM) materials with additional transition metal doping were selected and prepared via two different preparation methods. The optimum calcining conditions were determined using thermal analysis methods. The results of the structural analysis of the sintered electrolyte materials were used to select the most suitable electrolyte materials. As a result, LSGM and iron doped LSGM (LSGMF) were the most promising materials. Further investigations were carried out on LSGMF materials with different strontium content. The influence of chemical cation non-stoichiometry on the perovskite material was investigated. Therefore, measurements to gather information about the crystallographic structure, morphology, electrochemistry and electrical conductivity were carried out. For a selected sample, the correlations between single effects, such as the crystallographic structure, and the electrical properties are shown by combining the different analysis methods. It could be shown that both the electrochemistry and the crystallographic structure have a significant influence on the electrical conductivity of the LSGMF materials. The second aim of the thesis was the selection

  2. Continued maturing of SOFC cell production technology and development and demonstration of SOFC stacks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2008-08-15

    The overall objective of the 6385 project was to develop stack materials, components and stack technology including industrial relevant manufacturing methods for cells components and stacks. Furthermore, the project should include testing and demonstration of the stacks under relevant operating conditions. A production of 6.829 cells, twenty 75-cell stacks and a number of small stacks was achieved. Major improvements were also made in the manufacturing methods and in stack design. Two test and demonstration activities were included in the project. The first test unit was established at H.C. OErsted power plant at the Copenhagen waterfront in order to perform test of SOFC stacks. The unit will be used for tests in other projects. The second demonstration unit is the alpha prototype demonstration in a system running on natural gas in Finland. The alpha prototype demonstration system with 24 TOFC (Topsoe Fuel Cell) stacks was established and started running in October 2007 and operational experience was gained in the period from October 2007 to February 2008. (auther)

  3. High-velocity DC-VPS for diffusion and protecting barrier layers in solid oxide fuel cells (SOFCs)

    Science.gov (United States)

    Henne, R. H.; Franco, T.; Ruckdäschel, R.

    2006-12-01

    High-temperature fuel cells of the solid oxide fuel cell (SOFC) type as direct converter of chemical into electrical energy show a high potential for reducing considerably the specific energy consumption in different application fields. Of particular interest are advanced lightweight planar cells for electricity supply units in cars and other mobile systems. Such cells, in one new design, consist mainly of metallic parts, for example, of ferrite steels. These cells shall operate in the temperature range of 700 to 800 °C where oxidation and diffusion processes can be of detrimental effect on cell performance for long-term operation. Problems arise in particular by diffusion of chromium species from the interconnect or the cell containment into the electrolyte/cathode interface forming insulating phases and by the mutual diffusion of substrate and anode material, for example, iron and chromium from the ferrite into the anode and nickel from the anode into the ferrite, which in both cases reduces performance and system lifetime. Additional intermediate layers of perovskite-type material, (e.g., doped LaCrO3) applied with high-velocity direct-current vacuum plasma spraying (DC-VPS) can reduce such effects considerably if they are stable and of high electronic conductivity.

  4. Performance analysis of a SOFC under direct internal reforming conditions

    Energy Technology Data Exchange (ETDEWEB)

    Janardhanan, Vinod M.; Deutschmann, Olaf [Institute for Chemical Technology and Polymer Chemistry, Engesserstr 20, D-76131 Karlsruhe, University of Karlsruhe (Germany); Heuveline, Vincent [Institute for Applied and Numerical Mathematics, Kaiserstr. 12, D-76128 Karlsruhe (Germany)

    2007-10-11

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed. (author)

  5. Performance analysis of a SOFC under direct internal reforming conditions

    Science.gov (United States)

    Janardhanan, Vinod M.; Heuveline, Vincent; Deutschmann, Olaf

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed.

  6. Mechanistic Enhancement of SOFC Cathode Durability

    Energy Technology Data Exchange (ETDEWEB)

    Wachsman, Eric [Univ. of Maryland, College Park, MD (United States)

    2016-02-01

    Durability of solid oxide fuel cells (SOFC) under “real world” conditions is an issue for commercial deployment. In particular cathode exposure to moisture, CO2, Cr vapor (from interconnects and BOP), and particulates results in long-term performance degradation issues. Here, we have conducted a multi-faceted fundamental investigation of the effect of these contaminants on cathode performance degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability.

  7. Techno-Economic Feasibility of Highly Efficient Cost-Effective Thermoelectric-SOFC Hybrid Power Generation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jifeng Zhang; Jean Yamanis

    2007-09-30

    Solid oxide fuel cell (SOFC) systems have the potential to generate exhaust gas streams of high temperature, ranging from 400 to 800 C. These high temperature gas streams can be used for additional power generation with bottoming cycle technologies to achieve higher system power efficiency. One of the potential candidate bottoming cycles is power generation by means of thermoelectric (TE) devices, which have the inherent advantages of low noise, low maintenance and long life. This study was to analyze the feasibility of combining coal gas based SOFC and TE through system performance and cost techno-economic modeling in the context of multi-MW power plants, with 200 kW SOFC-TE module as building blocks. System and component concepts were generated for combining SOFC and TE covering electro-thermo-chemical system integration, power conditioning system (PCS) and component designs. SOFC cost and performance models previously developed at United Technologies Research Center were modified and used in overall system analysis. The TE model was validated and provided by BSST. The optimum system in terms of energy conversion efficiency was found to be a pressurized SOFC-TE, with system efficiency of 65.3% and cost of $390/kW of manufacturing cost. The pressurization ratio was approximately 4 and the assumed ZT of the TE was 2.5. System and component specifications were generated based on the modeling study. The major technology and cost barriers for maturing the system include pressurized SOFC stack using coal gas, the high temperature recycle blowers, and system control design. Finally, a 4-step development roadmap is proposed for future technology development, the first step being a 1 kW proof-of-concept demonstration unit.

  8. SOFC/TEG hybrid mCHP system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2012-03-15

    The starting point for this project have been the challenge has been to develop a cost effective solution with long term stability. This is where a focused effort in a strong consortium covering material research, module development and manufacture as well as device design and optimization can make a real difference. In March 2010 the SOFTEG phase II project was initiated and a cooperation organization was established to implement the project as a development and demonstration project involving the staff from all project partners. The project is now completed with excellent and documented outcome. The final results by Alpcon have been demonstration as a TEG-based mCHP system calls CHP Dual Engine Power System, which will be applicable as both a standalone TEG-CHP hybrid system, but also as an auxiliary power unit and power booster for the SOFC system. However the SOFC system cannot cover the household's heat demand alone so it is necessary to combine a SOFC system together with a water heater/boiler system to cover the peak heat demand of a residential house or a complex building. The SOFTEG project partners achieved significant results that mainly can be outlined as following: 1) University of Aarhus has improved the thermal stability of ZnSb by optimizing the concentration of Nano composite material. 2) The grain size and its influence on the sintering process by spark plasma method are investigated by Aarhus University, but further work seems to be necessary. 3) The TE material is going to commercialization by Aarhus University. 4) Aalborg University has prepared simulation tools for complex thermoelectric simulation in non-steady state condition. 5) The new type DCDC interleaved converter using the MPPT system for optimal power tracing is designed, build and tested by Aalborg University in cooperation with Alpcon. This task is included overall system design, control system implementation and power electronic control design. 6) Full scale practical

  9. Efficiency of SOFC type fuel cells; Eficiencia de celulas combustiveis do tipo SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Alexandre Alves do; Matos, Francisco F.; Boaventura, Jaime S.; Benedicto, Joao Paulo S.; Alencar, Marcelo [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2006-07-01

    production of electric energy, mainly due to the fact that it is virtually no pollutant. Typically, the SOFC is constituted of at least seven distinct phases: fuel, anode, electrolyte substrate (separating the two electrodes), cathode, air, and electrical inter connectors (completing the electrical circuit). Thermodynamics clearly shows that electrochemical systems only can be reversible when homogeneous, what it is not case of the Sofc. Therefore, the application of equilibrium thermodynamics to these systems is incorrect. This work proposes that the Sofc can be better depicted from reactions between adsorbed species. The efficiency then is calculated as the ratio between the free energy of these reactions to the combustion heat. Thermodynamic parameter estimative is developed for the global and adsorbed species reactions. (author)

  10. Life cycle assessment of an SOFC/GT process

    Energy Technology Data Exchange (ETDEWEB)

    Olausson, Pernilla

    1999-06-01

    For the last few years much effort has been put into the research on different kinds of fuel cells, since these are considered to be both an efficient and environment friendly way to convert energy. The fuel cell studied here is the solid oxide fuel cell (SOFC) that works at a high temperature (800-1000 C) and today achieves a stand-alone electric efficiency of approximately 50%. When integrating the SOFC in a gas turbine process (SOFC/GT process) an efficiency of 70-75% can be reached. The SOFC and the SOFC/GT process are considered to be environment friendly regarding the discharges during operation. Especially formation of nitrogen oxides (NO{sub x}) is low since the SOFC temperatures are low compared to NO{sub x} formation temperatures. To study the whole environmental impact of the SOFC/GT process a life cycle assessment (LCA) is carried out to find the `hot spots` in the process` life cycle. Since the SOFC/GT process is under development today the collected data are mainly from literature and articles based on laboratory results. When performing the LCA only the SOFC-module and the gas turbine are included. A collection of data of all processes included, extraction of minerals, processing of raw material, production of the components, operation of the SOFC/GT process and transports between all these processes. These data are then added up and weighted in impact categories to evaluate the total environmental impact of the SOFC/GT process. All these steps are performed according to the ISO 14040-series. The stand-alone most contributing phase during the life cycle of the SOFC/GT process was found to be the production of the SOFC. All processes during the production of the SOFC are carried out under laboratory circumstances, which require more energy and materials than if the processes were commercialised and optimised. For the SOFC/GT process to be competitive with other energy converting processes regarding the discharges of emissions to the air, the use of

  11. Development of a fuel flexible, air-regulated, modular, and electrically integrated SOFC-system (FlameSOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Voss, S.; Trimis, D. [TU Bergakademie Freiberg (Germany). Inst. of Thermal Engineering; Valldorf, J. [VDI/VDE Innovation + Technik GmbH (Germany)

    2010-07-01

    The present paper summarizes experimental results from the operation of the SOFC based micro-CHP unit developed within the framework of the project FlameSOFC. The project is co-financed by the European Commission as an Integrated Project within the 6{sup th} framework program. The objective is the development of an innovative SOFC-based micro-CHP system capable of operating with different gaseous and liquid fuels and fulfilling the technological and market requirements at a European level. The partners involved in the FlameSOFC project bring together a sufficient number of important European actors on the scientific, research and industry level including SMEs and industrial partners from the heating sector. The presented work concerns the operation of the 2{sup nd} phase prototype FlameSOFC system, with a 1 kW{sub el.} SOFC stack and natural gas as feedstock. (orig.)

  12. Dynamic model with experimental validation of a biogas-fed SOFC plant

    International Nuclear Information System (INIS)

    D'Andrea, G.; Gandiglio, M.; Lanzini, A.; Santarelli, M.

    2017-01-01

    Highlights: • 60% of DIR into the SOFC anode reduces the air blower parasitic losses by 14%. • PID-controlled cathode airflow enables fast thermal regulation of the SOFC. • Stack overheating occurs due to unexpected reductions in the cathode airflow. • Current ramp rates higher than +0.30 A/min lead to an excessive stack overheating. - Abstract: The dynamic model of a poly-generation system based on a biogas-fed solid oxide fuel cell (SOFC) plant is presented in this paper. The poly-generation plant was developed in the framework of the FP7 EU-funded project SOFCOM ( (www.sofcom.eu)), which consists of a fuel-cell based polygeneration plant with CO_2 capture and re-use. CO_2 is recovered from the anode exhaust of the SOFC (after oxy-combustion, cooling and water condensation) and the Carbon is fixed in the form of micro-algae in a tubular photobioreactor. This work focuses on the dynamic operation of the SOFC module running on steam-reformed biogas. Both steady state and dynamic operation of the fuel cell stack and the related Balance-of-Plant (BoP) has been modeled in order to simulate the thermal behavior and performance of the system. The model was validated against experimental data gathered during the operation of the SOFCOM proof-of-concept showing good agreement with the experimental data. The validated model has been used to investigate further on the harsh off-design operation of the proof-of-concept. Simulation results provide guidelines for an improved design of the control system of the plant, highlighting the feasible operating region under safe conditions and means to maximize the overall system efficiency.

  13. Numerical investigation of the effect of operating parameters on a planar solid oxide fuel cell

    International Nuclear Information System (INIS)

    Raj, Abhishek; Sasmito, Agus P.; Shamim, Tariq

    2015-01-01

    Highlights: • Effects of operating parameters on a planar type of SOFC are investigated. • The studies carried out by developing a three dimensional mathematical model. • The cell performance is enhanced at high temperatures and cathode stoichiometry. • Cathode stoichiometry has a high influence on the cell performance. • The effect of anode stoichiometry on the cell performance is low. - Abstract: The three operating parameters – temperature, stoichiometry and the degree of humidification – constitute key factors required to ensure high performance of the solid oxide fuel cell (SOFC). A careful trade-off between performance and parasitic loads is required in order to optimize the output. The present study numerically analyzes the influence of the key operating parameters on the performance of planar type of SOFC and parasitic loads utilizing a validated three dimensional mathematical model which takes into account of the conservation of mass, momentum, species and charge. The numerical results indicate that the cell performance is enhanced at high temperatures and cathode stoichiometry and it declines with increasing cathode relative humidity. Furthermore, cathode stoichiometry is found to have higher influence on the cell performance as compared to the anode stoichiometry. The gain in cell performance however, has to be balanced with the changing parasitic load requirement from pumping, humidification and heating. The results presented herein can assist in the selection of optimum or near-to-optimum operating parameters for high performance planar type SOFC

  14. Performance of planar single cell lanthanum gallate based solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Maffei, N.; Kuriakose, A.K. [Materials Technology Labs., CANMET, Natural Resources Canada, Ottawa, ON (Canada)

    1998-09-01

    A novel synthesis of high purity, single phase strontium-magnesium doped lanthanum gallate through a nitrate route is described. The prepared powder is formed into planar monolithic elements by uniaxial pressing followed by isostatic pressing and sintering. XRD analysis of the sintered elements reveal no detectable secondary phases. The performance of the electrolyte in solid oxide fuel cells (SOFC) with three different anode/cathode combinations tested at 700 C with respect to the J-V and power density is reported. The data show that the characteristics of this SOFC are strongly dependent on the particular anode/cathode system chosen. (orig.)

  15. Performance of planar single cell lanthanum gallate based solid oxide fuel cells

    Science.gov (United States)

    Maffei, N.; Kuriakose, A. K.

    A novel synthesis of high purity, single phase strontium-magnesium doped lanthanum gallate through a nitrate route is described. The prepared powder is formed into planar monolithic elements by uniaxial pressing followed by isostatic pressing and sintering. XRD analysis of the sintered elements reveal no detectable secondary phases. The performance of the electrolyte in solid oxide fuel cells (SOFC) with three different anode/cathode combinations tested at 700°C with respect to the J- V and power density is reported. The data show that the characteristics of this SOFC are strongly dependent on the particular anode/cathode system chosen.

  16. Cathode-Electrolyte Interfaces with CGO Barrier Layers in SOFC

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Hjelm, Johan; Menon, Mohan

    2010-01-01

    Electron microscopy characterization across the cathode–electrolyte interface of two different types of intermediate temperature solid oxide fuel cells (IT-SOFC) is performed to understand the origin of the cell performance disparity. One IT-SOFC cell had a sprayed-cosintered Ce0.90Gd0.01O1.95 (CGO...

  17. Integrating a SOFC Plant with a Steam Turbine Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Scappin, Fabio

    2009-01-01

    A Solid Oxide Fuel Cell (SOFC) is integrated with a Steam Turbine (ST) cycle. Different hybrid configurations are studied. The fuel for the plants is assumed to be natural gas (NG). Since the NG cannot be sent to the anode side of the SOFC directly, a desulfurization reactor is used to remove...

  18. Solid Oxide Fuel Cell (SOFC) Development in Denmark

    DEFF Research Database (Denmark)

    Linderoth, Søren; Larsen, Peter Halvor; Mogensen, Mogens Bjerg

    2007-01-01

    on larger anode-supported cells as well as a new generation of SOFCs based on porous metal supports and new electrode and electrolyte materials. The SOFC program comprises development of next generation of cells and multi stack modules for operation at lower temperature with increased durability...

  19. Technology watch of stationary solid oxide fuel cells (SOFC) 2012; Teknikbevakning av stationaera fastoxidbraensleceller (SOFC) 2012

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Martin; Sunden, Bengt

    2013-03-15

    The first solid oxide fuel cell (SOFC) was developed in 1937. However, the commercialization has waited. In 2012, 20MW of SOFC-systems are expected to be delivered to customers, compared to 1.3 MW in 2008. It is mainly in specific niche markets, such as on-site power generation for data centers, small-scale CHP for individual households and as military applications, where SOFC systems are available today. The future potential is enormous in the just mentioned areas as well as for APUs in trucks and other vehicles as well as for MW-scale distributed power generation. There are public research program, support for demonstration projects and investment support to private households as well as companies in various terms around the world. EU invests SEK 666 million (distributed at hydrogen, fuel cells for transportation, stationary systems and cogeneration) in the FCH-JU program only in 2012, compared with SEK 1.59 billion in the Japanese program (of which 125 million is directed to SOFC research and 740 million to the ENE-FARM project to be distributed between PEMFC and SOFC). The German hydrogen and fuel cell program is SEK 12 billion during 2006-2016 (of which 54% to transportation applications, 36% to stationary applications and 10% to special applications), compared with the Finnish program that invest SEK 1.3 billion in 2007-2013. The federal SECA program directs SEK 160 million to SOFC research. Denmark goes slightly over SEK 115 million annually in public funds for fuel cell research. The trend is that the proportion of public funding for demonstration projects and support to customers for purchasing pre-commercial products is increasing at the expense of basic research funding. Note that the listed research programs involve different types of fuel cells, and information regarding the percentage that goes to SOFCs is not specified for each case. Research continues to deliver new advances. Researchers at Harvard have shown that a SOFC, with vanadium oxide in the

  20. Solid oxide fuel cells, SOFC, in future power generation; Fastoxidbraensleceller, SOFC, i framtida kraftgenerering

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Kent; Baafaelt, M

    1997-02-01

    Solid Oxide Fuel Cell, SOFC, is a very promising technological area for generating electricity in the future. Especially for small scale cogeneration. SOFC is an excellent choice due to its high efficiencies at small power plant sizes. The expected size of the power plants is 10-20 MWe but larger ones might be built. An important part of the assumptions in this report is the SOFC electric efficiency dependence of the pressure in the process. The electric efficiency is assumed to be 50% at atmospheric pressure and 55% at 10 atmospheres. These assumptions lead to a formula that describes the electric efficiency as a function of the pressure. The parametric study shows that the pressure has a very large influence of the electric efficiency. At low pressure and high Turbine Inlet Temperature (TIT) the electric efficiency will be higher than at high pressure and low TIT. The post intercooler temperature and the pressure drop over the SOFC unit have a moderate effect on the electric efficiency. In the process calculations the TIT is shown to have a very small influence on the plant efficiencies. Consequently, by lowering the TIT, the need for blade cooling and tougher materials can be avoided, with only a small electric efficiency decrease. The recuperator is a central part of the process. It evens out the influence from other parts in the process. This is one of the reasons why the polytropic efficiencies of the compressor and the expander have such a low influence on the process efficiency. The report shows that to receive high efficiencies in a SOFC/GT power plant, the points mentioned below should be taken into consideration: The pressure in the process should be approximately 4 bar; The compressor should have an intercooler; The TIT should be below the temperature where blade cooling is needed; No steam cycle should be connected after the gas turbine at sizes of 5-20 MW. 32 refs, 67 figs, 9 tabs, 15 appendices

  1. Integrated Gasification SOFC Plant with a Steam Plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Pierobon, Leonardo

    2011-01-01

    A hybrid Solid Oxide Fuel Cell (SOFC) and Steam Turbine (ST) plant is integrated with a gasification plant. Wood chips are fed to the gasification plant to produce biogas and then this gas is fed into the anode side of a SOFC cycle to produce electricity and heat. The gases from the SOFC stacks...... enter into a burner to burn the rest of the fuel. The offgases after the burner are now used to generate steam in a Heat Recovery Steam Generator (HRSG). The generated steam is expanded in a ST to produce additional power. Thus a triple hybrid plant based on a gasification plant, a SOFC plant...... and a steam plant is presented and studied. The plant is called as IGSS (Integrated Gasification SOFC Steam plant). Different systems layouts are presented and investigated. Electrical efficiencies up to 56% are achieved which is considerably higher than the conventional integrated gasification combined...

  2. Study of Operating Parameters for Accelerated Anode Degradation in SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    2017-01-01

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to demonstrate such exceptionally long lifetimes in ongoing R&D projects. Accelerated or compressed testing are alternative methods to obtain this. Activities in this area have been...... carried out without arriving at a generally accepted methodology. This is mainly due to the complexity of degradation mechanisms on the single SOFC components as function of operating parameters. In this study, we present a detailed analysis of approx. 180 durability tests regarding degradation of single...... SOFC components as function of operating conditions. Electrochemical impedance data were collected on the fresh and long-term tested SOFCs and used to de-convolute the individual losses of single SOFC cell components – electrolyte, cathode and anode. The main findings include a time-dependent effect...

  3. Transport properties and device-design of Z-shaped MoS2 nanoribbon planar junctions

    Science.gov (United States)

    Zhang, Hua; Zhou, Wenzhe; Liu, Qi; Yang, Zhixiong; Pan, Jiangling; Ouyang, Fangping; Xu, Hui

    2017-09-01

    Based on MoS2 nanoribbons, metal-semiconductor-metal planar junction devices were constructed. The electronic and transport properties of the devices were studied by using density function theory (DFT) and nonequilibrium Green's functions (NEGF). It is found that a band gap about 0.4 eV occurs in the planar junction. The electron and hole transmissions of the devices are mainly contributed by the Mo atomic orbitals. The electron transport channel is located at the edge of armchair MoS2 nanoribbon, while the hole transport channel is delocalized in the channel region. The I-V curve of the two-probe device shows typical transport behavior of Schottky barrier, and the threshold voltage is of about 0.2 V. The field effect transistors (FET) based on the planar junction turn out to be good bipolar transistors, the maximum current on/off ratio can reach up to 1 × 104, and the subthreshold swing is 243 mV/dec. It is found that the off-state current is dependent on the length and width of the channel, while the on-state current is almost unaffected. The switching performance of the FET is improved with increasing the length of the channel, and shows oscillation behavior with the change of the channel width.

  4. Design and Fabrication of a Ratiometric Planar Optode for Simultaneous Imaging of pH and Oxygen

    Directory of Open Access Journals (Sweden)

    Zike Jiang

    2017-06-01

    Full Text Available This paper presents a simple, high resolution imaging approach utilizing ratiometric planar optode for simultaneous measurement of dissolved oxygen (DO and pH. The planar optode comprises a plastic optical film coated with oxygen indicator Platinum(II octaethylporphyrin (PtOEP and reference quantum dots (QDs embedded in polystyrene (PS, pH indicator 5-Hexadecanoylamino-fluorescein (5-Fluorescein embedded in Hydromed D4 matrix. The indicator and reference dyes are excited by utilizing an LED (Light Emitting Diode source with a central wavelength of 405 nm, the emission respectively matches the different channels (red, green, and blue of a 3CCD camera after eliminating the excitation source by utilizing the color filter. The result shows that there is low cross-sensitivity between the two analytes dissolved oxygen and pH, and it shows good performance in the dynamic response ranges of 0–12 mg/L and a dynamic range of pH 6−8. The optode has been tested with regard to the response times, accuracy, photostability and stability. The applied experiment for detecting pH/Oxygen of sea-water under the influence of the rain drops is demonstrated. It is shown that the planar optode measuring system provides a simple method with low cross-talk for pH/Oxygen imaging in aqueous applications.

  5. Planar metasurface retroreflector

    Science.gov (United States)

    Arbabi, Amir; Arbabi, Ehsan; Horie, Yu; Kamali, Seyedeh Mahsa; Faraon, Andrei

    2017-07-01

    Metasurfaces are two-dimensional arrangements of subwavelength scatterers that control the propagation of optical waves. Here, we show that cascaded metasurfaces, each performing a predefined mathematical transformation, provide a new optical design framework that enables new functionalities not yet demonstrated with single metasurfaces. Specifically, we demonstrate that retroreflection can be achieved with two vertically stacked planar metasurfaces, the first performing a spatial Fourier transform and its inverse, and the second imparting a spatially varying momentum to the Fourier transform of the incident light. Using this concept, we fabricate and test a planar monolithic near-infrared retroreflector composed of two layers of silicon nanoposts, which reflects light along its incident direction with a normal incidence efficiency of 78% and a large half-power field of view of 60°. The metasurface retroreflector demonstrates the potential of cascaded metasurfaces for implementing novel high-performance components, and enables low-power and low-weight passive optical transmitters.

  6. Development of Robust Metal-Supported SOFCs and Stack Components in EU METSAPP Consortium

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Persson, Åsa Helen

    2017-01-01

    -SOFCs to enhance their robustness. In addition, the manufacturing of metal-supported cells with different geometries, scalability of the manufacturing process was demonstrated and more than 200 cells with an area of ∼150 cm2 were produced. The electrochemical performance of different cell generations was evaluated...... in 90% reduction in Cr evaporation, three times lower Cr2O3 scale thickness and increased lifetime. The possibility of assembling these cells into two radically different stack designs was demonstrated....

  7. Development of a Planar Undulator

    International Nuclear Information System (INIS)

    Deyhim, Alex; Johnson, Eric; Kulesza, Joe; Lyndaker, Aaron; Waterman, Dave; Eisert, Dave; Green, Michael A.; Rogers, Greg; Blomqvist, K. Ingvar

    2007-01-01

    The design of a planar pure permanent magnet undulator is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural, thermal, and electrical considerations that influenced the design are then analyzed. And finally detailed magnetic measurements are presented

  8. Development of a 1 kW Class SOFC Stack using Doped Lanthanum Gallate

    Energy Technology Data Exchange (ETDEWEB)

    Akikusa, J.; Adachi, K.; Yamada, T.; Akbay, T.; Murakami, N.; Chitose, N.; Hoshino, K.; Hosoi, K.; Yoshida, H.; Sasaki, T.; Inagaki, T.; Ishihara, T.; Takita, Y.

    2002-06-01

    The performance of lanthanum gallate based SOFC has been investigated as a high-energy conversion device. A planar type SOFC which could operate at temperatures below 800 {sup o}C has been jointly developed. As an electrolyte material, lanthanum gallate (LaGaO{sub 3}) with substitutions of Sr for the La site and Mg and Co for the Ga site (LSGMC) was used. The synthesis technique for large-sized cell production has been established, and the performance of a self- supported diameter 154 mm cell with 200 {mu}m electrolyte thickness is investigated. The output power of 50 W has been obtained with a conversion efficiency [LHV] of 45 % for a single cell. In addition, a metallic separator made of stainless steel was chosen and tested successfully for a seal-less stack. The output power of 1 kW by means of the stack of 18 cells has been achieved for the first time utilizing lanthanum gallate. Moreover, NiO-SDC composite powders were prepared by the spray pyrolysis method and used for the anode on 100 {mu}m thickness LSGMC electrolyte with a combination of samarium cobaltite for the cathode. The power density of as high as 1.8 W/cm{sup 2} at 0.7 V terminal voltage was achieved at 800{sup o}C. (author)

  9. AC impedance behavior of a practical-size single-cell SOFC under DC current

    Energy Technology Data Exchange (ETDEWEB)

    Momma, Akihiko; Kaga, Yasuo; Takano, Kiyonami; Nozaki, Ken; Negishi, Akira; Kato, Ken; Kato, Tohru [Fuel Cell Group, Energy Electronics Institute, National Institute of Advanced Industrial Science and Technology, Umezono Tsukuba-shi, Ibaraki 305-8568 (Japan); Inagaki, Toru; Yoshida, Hiroyuki [Energy Use R and D Center, The Kansai Electric Power Company, Inc., 11-20 Nakoji, 3-Chome, Amagasaki, Hyogo 661-0974 (Japan); Hosoi, Kei; Hoshino, Koji; Akbay, Taner; Akikusa, Jun; Yamada, Masaharu; Chitose, Norihisa [Central Research Institute, Naka Research Center, Mitsubishi Materials Corp. 1002-14 Mukohyama, Naka-machi, Naka-gun, Ibaraki 311-0102 (Japan)

    2004-10-29

    AC impedance measurements were carried out using practical-size planar disc-type SOFC which employs lanthanum gallate as a solid electrolyte. The data were obtained under practical conditions of gas flow rate and DC current. Under these conditions, the gas conversion impedance (GCI), which originates from the change of the electromotive force (EMF) caused by the change in anodic gaseous concentrations along the flow direction, was observed in the low-frequency range of the data obtained. The overlapping impedance together with GCI on the low-frequency arc was also estimated. Experimentally obtained GCI was in good agreement with that calculated. It was concluded that GCI was predominant in the impedance data obtained under practical conditions. The shift of the high-frequency intercept in the complex impedance diagrams was shown to appear as a result of the change in the distribution of gaseous composition in the anode. The dependency of the low-frequency arc on temperature was also shown, and it was assumed that the overlapped impedance varies as the temperature changes. The validity of the impedance measurement, as a diagnostic means to evaluate the gas flow in SOFC stack, was suggested.

  10. Analyses of Large Coal-Based SOFCs for High Power Stack Block Development

    Energy Technology Data Exchange (ETDEWEB)

    Recknagle, Kurtis P; Koeppel, Brian J

    2010-10-01

    This report summarizes the numerical modeling and analytical efforts for SOFC stack development performed for the coal-based SOFC program. The stack modeling activities began in 2004, but this report focuses on the most relevant results obtained since August 2008. This includes the latter half of Phase-I and all of Phase-II activities under technical guidance of VPS and FCE. The models developed to predict the thermal-flow-electrochemical behaviors and thermal-mechanical responses of generic planar stacks and towers are described. The effects of cell geometry, fuel gas composition, on-cell reforming, operating conditions, cell performance, seal leak, voltage degradation, boundary conditions, and stack height are studied. The modeling activities to evaluate and achieve technical targets for large stack blocks are described, and results from the latest thermal-fluid-electrochemical and structural models are summarized. Modeling results for stack modifications such as scale-up and component thickness reduction to realize cost reduction are presented. Supporting modeling activities in the areas of cell fabrication and loss of contact are also described.

  11. Infiltrated SrTiO3:FeCr‐based Anodes for Metal‐Supported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Reddy Sudireddy, Bhaskar; Persson, Åsa Helen

    2013-01-01

    The concept of using electronically conducting anode backbones with subsequent infiltration of electrocatalytic active materials has been used to develop an alternative solid oxide fuel cell (SOFC) design based on a ferritic stainless steel support. The anode backbone consists of a composite made...

  12. Infiltrated SrTiO3:FeCr-based anodes for metalsupported SOFC

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Persson, Åsa Helen; Nielsen, Jimmi

    2012-01-01

    The concept of using highly electronically conducting backbones with subsequent infiltration of electrocatalytic active materials, has recently been used to develop an alternative SOFC design based on a ferritic stainless steel support. The metal-supported SOFC is comprised of porous and highly e...... changes occurring in the anode layer during testing. The results indicate that the STN component in the anode seems to have a positive effect on the corrosion stability of the FeCr-particles in the anode layer.......) and FeCr. Electrochemical characterization and post test SEM analysis have been used to get an insight into the possible degradation mechanisms of this novel electrode infiltrated with Gd-doped CeO2 and Ni. Accelerated oxidation/corrosion experiments have been conducted to evaluate the microstructural...

  13. Analytical investigation on cell temperature control method of planar solid oxide fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Inui, Y.; Ito, N.; Nakajima, T.; Urata, A. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi (Japan)

    2006-09-15

    The solid oxide fuel cell (SOFC) has a problem in durability of the ceramics used as its cell materials because its operating temperature is very high and the cell temperature fluctuation induces thermal stress in the ceramics. The cell temperature distribution in the SOFC, therefore, should be kept as constant as possible during variable load operation through control of the average current density in the cell. Considering this fact, the authors numerically optimize the operating parameters of air utilization and the inlet gas temperature of the planar SOFC by minimizing the cell temperature shift from its nominal value and propose a new cell temperature control method that adopts these optimum operating parameters for each average current density. The effectiveness of the proposed method is very high and the temperature variation is suppressed to a very low level without lowering the single cell voltage for both the co-flow and counter-flow type cells, indicating that the proposed cell temperature control method makes variable load operation of the planar SOFC possible. (author)

  14. Optimal integration strategies for a syngas fuelled SOFC and gas turbine hybrid

    Science.gov (United States)

    Zhao, Yingru; Sadhukhan, Jhuma; Lanzini, Andrea; Brandon, Nigel; Shah, Nilay

    This article aims to develop a thermodynamic modelling and optimization framework for a thorough understanding of the optimal integration of fuel cell, gas turbine and other components in an ambient pressure SOFC-GT hybrid power plant. This method is based on the coupling of a syngas-fed SOFC model and an associated irreversible GT model, with an optimization algorithm developed using MATLAB to efficiently explore the range of possible operating conditions. Energy and entropy balance analysis has been carried out for the entire system to observe the irreversibility distribution within the plant and the contribution of different components. Based on the methodology developed, a comprehensive parametric analysis has been performed to explore the optimum system behavior, and predict the sensitivity of system performance to the variations in major design and operating parameters. The current density, operating temperature, fuel utilization and temperature gradient of the fuel cell, as well as the isentropic efficiencies and temperature ratio of the gas turbine cycle, together with three parameters related to the heat transfer between subsystems are all set to be controllable variables. Other factors affecting the hybrid efficiency have been further simulated and analysed. The model developed is able to predict the performance characteristics of a wide range of hybrid systems potentially sizing from 2000 to 2500 W m -2 with efficiencies varying between 50% and 60%. The analysis enables us to identify the system design tradeoffs, and therefore to determine better integration strategies for advanced SOFC-GT systems.

  15. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José ; Burriel, Mó nica

    2010-01-01

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation

  16. Hybrid Metal/Electrolyte Monolithic Low Temperature SOFCs

    National Research Council Canada - National Science Library

    Cochran, Joe

    2004-01-01

    The program objective is to develop SOFCs, operating in the 500-700 degrees C range, based on Metal/Electrolyte square cell honeycomb formed by simultaneous powder extrusion of electrolyte and metal...

  17. Study of a SOFC-PEM hybrid system

    International Nuclear Information System (INIS)

    Fillman, B.; Bjornbom, P.; Sylwan, C.

    2004-01-01

    'Full text:' In the present project a system study of a SOFC-PEM hybrid system is in progress. Positive synergy effects are expected when combining a SOFC system with a PEM system. By combining the advantages of each fuel cell type it is promising that the hybrid system has higher overall efficiency than a SOFC-only system or a reformer-PEM system. A SOFC stack produces electricity and a reformate gas that can be further processed to hydrogen by the shift reaction. The produced hydrogen can be used by PEM stack in order to produce further electricity. In the PEM system case the complex fuel reformer processing could be eliminated. The simulations were performed with the flowsheeting simulation software Aspen Plus. (author)

  18. SOFC anode reduction studied by in situ TEM

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    The Solid Oxide Fuel Cell (SOFC) is a promising part of future energy approaches due to a relatively high energy conversion efficiency and low environmental pollution. SOFCs are typically composed of ceramic materials which are highly complex at the nanoscale. TEM is routinely applied ex situ...... for studying these nanoscale structures, but only few SOFC studies have applied in situ TEM to observe the ceramic nanostructures in a reactive gas environment at elevated temperatures. The present contribution focuses on the reduction of an SOFC anode which is a necessary process to form the catalytically...... active Ni surface before operating the fuel cells. The reduction process was followed in the TEM while exposing a NiO/YSZ (YSZ = Y2O3-stabilized ZrO2) model anode to H2 at T = 250-1000⁰C. Pure NiO was used in reference experiments. Previous studies have shown that the reduction of pure Ni...

  19. Dynamic Analysis of Load Operations of Two-Stage SOFC Stacks Power Generation System

    Directory of Open Access Journals (Sweden)

    Paulina Pianko-Oprych

    2017-12-01

    Full Text Available The main purpose of this paper was to develop a complete dynamic model of a power generation system based on two serially connected solid oxide fuel cell stacks. The uniqueness of this study lies in a different number of fuel cells in the stacks. The model consists of the electrochemical model, mass and energy balance equations implemented in MATLAB Simulink environment. Particular attention has been paid to the analysis of the transient response of the reformers, fuel cells and the burner. The dynamic behavior of the system during transient conditions was investigated by load step changing. The model evaluates electrical and thermal responses of the system at variable drawn current. It was found that a decrease of 40% in the 1st stage and 2nd solid oxide fuel cell (SOFC stacks drawn current caused both stacks temperature to drop by 2%. An increase of the cell voltage for the 1st and 2nd SOFC stacks led to very fast steam reformer response combined with a slight decrease in reformer temperature, while a considerable burner temperature increase of 70 K can be observed. Predictions of the model provide the basic insight into the operation of the power generation-based SOFC system during various transients and support its further design modifications.

  20. Planar quadrature RF transceiver design using common-mode differential-mode (CMDM transmission line method for 7T MR imaging.

    Directory of Open Access Journals (Sweden)

    Ye Li

    Full Text Available The use of quadrature RF magnetic fields has been demonstrated to be an efficient method to reduce transmit power and to increase the signal-to-noise (SNR in magnetic resonance (MR imaging. The goal of this project was to develop a new method using the common-mode and differential-mode (CMDM technique for compact, planar, distributed-element quadrature transmit/receive resonators for MR signal excitation and detection and to investigate its performance for MR imaging, particularly, at ultrahigh magnetic fields. A prototype resonator based on CMDM method implemented by using microstrip transmission line was designed and fabricated for 7T imaging. Both the common mode (CM and the differential mode (DM of the resonator were tuned and matched at 298MHz independently. Numerical electromagnetic simulation was performed to verify the orthogonal B1 field direction of the two modes of the CMDM resonator. Both workbench tests and MR imaging experiments were carried out to evaluate the performance. The intrinsic decoupling between the two modes of the CMDM resonator was demonstrated by the bench test, showing a better than -36 dB transmission coefficient between the two modes at resonance frequency. The MR images acquired by using each mode and the images combined in quadrature showed that the CM and DM of the proposed resonator provided similar B1 coverage and achieved SNR improvement in the entire region of interest. The simulation and experimental results demonstrate that the proposed CMDM method with distributed-element transmission line technique is a feasible and efficient technique for planar quadrature RF coil design at ultrahigh fields, providing intrinsic decoupling between two quadrature channels and high frequency capability. Due to its simple and compact geometry and easy implementation of decoupling methods, the CMDM quadrature resonator can possibly be a good candidate for design blocks in multichannel RF coil arrays.

  1. Analysis of cathode materials of perovskite structure for solid oxide fuel cells, sofc s; Analisis de materiales catodicos de estructura perovskita para celdas de combustible de oxido solido, sofcs

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado F, J.; Espino V, J.; Avalos R, L. [Universidad Michoacana de San Nicolas de Hidalgo, Facultad de Ingenieria Quimica, Santiago Tapia 403, Morelia, Michoacan (Mexico)

    2015-07-01

    Fuel cells directly and efficiently convert the chemical energy of a fuel into electrical energy. Of the various types of fuel cells, the solid oxide (Sofc), combine the advantages in environmentally benign energy generation with fuel flexibility. However, the need for high operating temperatures (800 - 1000 grades C) has resulted in high costs and major challenges in relation to the compatibility the cathode materials. As a result, there have been significant efforts in the development of intermediate temperature Sofc (500 - 700 grades C). A key obstacle for operation in this temperature range is the limited activity of traditional cathode materials for electrochemical reduction oxygen. In this article, the progress of recent years is discussed in cathodes for Sofc perovskite structure (ABO{sub 3}), more efficient than the traditionally used La{sub 1-x}Sr{sub x}MnO{sub 3-δ} (LSM) or (La, Sr) CoO{sub 3}. Such is the case of mixed conductors (MIEC) double perovskite structure (A A B{sub 2}O{sub 5+δ}) using different doping elements as La, Sr, Fe, Ti, Cr, Sm, Co, Cu, Pr, Nd, Gd, dy, Mn, among others, which could improve the operational performance of existing cathode materials, promoting the development of optimized intermediate temperature Sofc designs. (Author)

  2. Vaporization of materials in the operation of high temperature fuel cells (SOFCs); Verdampfung von Werkstoffen beim Betrieb von Hochtemperaturbrennstoffzellen (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, M.

    2006-07-01

    One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance. A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800 C to 700 C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed. Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800 C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75 % compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90 % reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. Concerning the vaporization of doped lanthanum gallates the vaporization rates of the elements Ga, Mg, Sr and La were measured as function time, temperature, gas flow rate and stoichiometry

  3. Design Features of a Planar Hybrid/Permanent Magnet Strong Focusing Undulator for Free Electron Laser (FEL) And Synchrotron Radiation (SR) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, Roman; /SLAC

    2011-09-09

    Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.

  4. Characterization of ceria-based SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, R.; Routbort, J.; Krumpelt, M. [Argonne National Lab., IL (United States)

    1996-12-31

    Solid Oxide Fuel Cells (SOFCs) operating at low temperatures (500-700{degrees}C) offer many advantages over the conventional zirconia-based fuel cells operating at higher temperatures. Reduced operating temperatures result in: (1) Application of metallic interconnects with reduced oxidation problems (2) Reduced time for start-up and lower energy consumption to reach operating temperatures (3) Increased thermal cycle ability for the cell structure due to lower thermal stresses of expansion mismatches. While this type of fuel cell may be applied to stationary applications, mobile applications require the ability for rapid start-up and frequent thermal cycling. Ceria-based fuel cells are currently being developed in the U.K. at Imperial College, Netherlands at ECN, and U.S.A. at Ceramatec. The cells in each case are made from a doped ceria electrolyte and a La{sub 1-x}Sr{sub x}Co{sub 1-y}Fe{sub y}O{sub 3} cathode.

  5. System requirements of diesel reforming for the SOFC

    International Nuclear Information System (INIS)

    Harasti, P.T.; Amphlett, J.C.; Mann, R.F.; Peppley, B.A.; Thurgood, C.P.

    2003-01-01

    Diesel fuels are currently a very attractive source of hydrogen due to the global infrastructure for production and distribution that exists today. In order to extract the hydrogen, the hydrocarbon molecules must be chemically reformed into manageable, hydrogen-rich product gases that can be directly used in electrochemical energy conversion devices such as fuel cells. High temperature fuel cells are particularly attractive for diesel-fuelled systems due to the possibility of thermal integration with the high temperature reformer. The methods available for diesel fuel processing are: Steam Reforming, Partial Oxidation, and Auto-Thermal Reforming. The latter two methods introduce air into the process in order to cause exothermic oxidation reactions, which complement the endothermic heating requirement of the reforming reactions. This helps to achieve the high temperature required, but also introduces nitrogen, which can yield unwanted NO x emissions. The components of the reformer should include: an injection system to mix and vaporize the diesel fuel and steam while avoiding the formation of carbon deposits inside the reactor; a temperature and heat management system; and a method of sulphur removal. This presentation will discuss the operating conditions and design requirements of a diesel fuel processor for a solid oxide fuel cell (SOFC) system. (author)

  6. High temperature sealing method : induction brazing for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Y.H.; Lee, S.B.; Song, R.H.; Shin, D.R. [Korea Inst. of Energy Research, Daejeon (Korea, Republic of); Lim, T.H. [Korea Inst. of Energy Research, Daejeon (Korea, Republic of). Advanced Fuel Cell Research Center

    2009-07-01

    This study examined the use of induction brazing as a high temperature sealing method for solid oxide fuel cells (SOFCs). Nickel-based brazing alloys were modified using reactive titanium-hydride (TiH2). The gas sealing properties of the induction brazing process on anode-supported tubular SOFCs and ferritic stainless steel were evaluated. Brazing alloys BNi-2 and BNi-4 were not wetted in a yttria-silica-zircon (YSZ) electrolyte. The brazing alloy with added TiH2 showed good wettability with the YSZ electrolyte as a result of the formation of a TiOX layer. Only the BNi-4 alloy joined with the YSZ electrolyte. An open circuit voltage (OCV) value was used to estimate the gas tightness of the brazed cell. It was concluded that the BNi-4 TiH2 modified alloy is a suitable sealing material for SOFCs operating in temperatures up to 750 degrees C.

  7. Deposition and characterisation of epitaxial oxide thin films for SOFCs

    KAUST Repository

    Santiso, José

    2010-10-24

    This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported. © 2010 Springer-Verlag.

  8. In-Situ Raman Characterization of SOFC Anodes

    KAUST Repository

    Maher, Robert C.; Offer, Gregory; Brandon, Nigel P.; Cohen, Lesley F.

    2012-01-01

    Solid oxide fuel cells (SOFCs) have many advantages when compared to other fuel cell technologies, particularly for distributed stationary applications. As a consequence they are becoming ever more economically competitive with incumbent energy solutions. However, as with all technologies, improvements in durability, efficiency and cost is required before they become feasible alternatives. Such improvements are enabled through improved understanding of the critical material interactions occurring during operation. Raman spectroscopy is a noninvasive and non-destructive optical characterization tool which is ideally suited to the study of these critical chemical processes occurring within operational SOFCs. In this paper we will discuss advantages of using Raman characterization for understanding these important chemical processes occurring within SOFCs. We will present the specific examples of the type of measurement possible and discuss the direction of future research. © 2012 Materials Research Society.

  9. A New Design Strategy for Efficient Thermally Activated Delayed Fluorescence Organic Emitters: From Twisted to Planar Structures

    KAUST Repository

    Chen, Xiankai; Tsuchiya, Youichi; Ishikawa, Yuma; Zhong, Cheng; Adachi, Chihaya; Bredas, Jean-Luc

    2017-01-01

    In the traditional molecular design of thermally activated delayed fluorescence (TADF) emitters composed of electron-donor and electron-acceptor moieties, achieving a small singlet-triplet energy gap (ΔEST ) in strongly twisted structures usually

  10. Testing and Evaluation of an Advanced High Performance Planar SOFC Stack

    National Research Council Canada - National Science Library

    Elangovan, S

    1999-01-01

    .... SOFCo has conducted several programs which synergistically address this objective: an internally funded program focusing on stack development and system integration for pipeline natural gas (PNG...

  11. Synchrotron Investigations of SOFC Cathode Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Idzerda, Yves

    2013-09-30

    The atomic variations occurring in cathode/electrolyte interface regions of La{sub 1-x}Sr{sub x}Co{sub y}Fe{sub 1-y}O{sub 3-δ} (LSCF) cathodes and other SOFC related materials have been investigated and characterized using soft X-ray Absorption Spectroscopy (XAS) and diffuse soft X-ray Resonant Scattering (XRS). X-ray Absorption Spectroscopy in the soft X-ray region (soft XAS) is shown to be a sensitive technique to quantify the disruption that occurs and can be used to suggest a concrete mechanism for the degradation. For LSC, LSF, and LSCF films, a significant degradation mechanism is shown to be Sr out-diffusion. By using the XAS spectra of hexavalent Cr in SrCrO4 and trivalent Cr in Cr2O3, the driving factor for Sr segregation was identified to be the oxygen vacancy concentration at the anode and cathode side of of symmetric LSCF/GDC/LSCF heterostructures. This is direct evidence of vacancy induced cation diffusion and is shown to be a significant indicator of cathode/electrolyte interfacial degradation. X-ray absorption spectroscopy is used to identify the occupation of the A-sites and B-sites for LSC, LSF, and LSCF cathodes doped with other transition metals, including doping induced migration of Sr to the anti-site for Sr, a significant cathode degradation indicator. By using spatially resolved valence mapping of Co, a complete picture of the surface electrochemistry can be determined. This is especially important in identifying degradation phenomena where the degradation is spatially localized to the extremities of the electrochemistry and not the average. For samples that have electrochemical parameters that are measured to be spatially uniform, the Co valence modifications were correlated to the effects of current density, overpotential, and humidity.

  12. Determination of global and local residual stresses in SOFC by X-ray diffraction

    International Nuclear Information System (INIS)

    Villanova, Julie; Sicardy, Olivier; Fortunier, Roland; Micha, Jean-Sebastien; Bleuet, Pierre

    2010-01-01

    Solid Oxide Fuel Cell (SOFC) is a high-performance electrochemical device for energy conversion. A single cell is composed of five layers made of different ceramic materials: anode support, anode functional layer, electrolyte, cathode functional layer and cathode. The mechanical integrity of the cell is a major issue during its lifetime, especially for the electrolyte layer. Damage of the cells is mainly due to the high operating temperature, the 'redox' behaviour of the anode and the brittleness of the involved materials. Since residual stresses are known to play a significant role in the damage evolution, it is important to determine them. For this purpose, residual stresses in an anode-supported planar SOFC were measured by X-ray diffraction. Firstly, macroscopic stresses in each phase of each layer were studied using the sin 2 ψ method on a laboratory X-ray goniometer at room temperature. This technique enables the calculation of residual stress of the material from the measurement of the crystal lattice deformation. The electrolyte has been found under bi-axial compressive stress of -920 MPa. Secondly, X-ray measurements controlling depth penetration were made in the electrolyte using grazing incidence method. The results show that the stress is not homogenous in the layer. The first five micrometers of the electrolyte have been found less constrained (-750 MPa) than the complete layer, suggesting a gradient of deformation in the electrolyte from the interface with the Anode Functional Layer to the free surface. Finally, local stress measurements were made on the electrolyte layer by X-ray synchrotron radiation that allows high accuracy measurement on the (sub-) micrometer scale. Polychromatic and monochromatic beams are used to determine the complete strain tensor from grain to grain in the electrolyte. First results confirm the macroscopic stress trend of the electrolyte. These X-ray techniques at different scales will contribute to a better understanding

  13. Fuel flow distribution in SOFC stacks revealed by impedance spectroscopy

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, Rasmus

    2014-01-01

    As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation. An oper......As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation...... utilizations. The fuel flow distribution provides important information about the operating limits of the stack when high electrical efficiency is required....

  14. Study of variables for accelerating lifetime testing of SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to proof/confirm/demonstrate such exceptionally long lifetimes.Accelerated or compressed testing are possible methods. Activities in this area have been carried out without arriving...... at different current load cycling profiles revealed a strong deviation between predicted and measured lifetime [3].In this study, we present a detailed analysis of durability results for degradation mechanisms of single SOFC components as function of operating conditions. Electrochemical impedance data...

  15. Thermodynamic analysis of SOFC (solid oxide fuel cell) - Stirling hybrid plants using alternative fuels

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated...... to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes...

  16. Plant Characteristics af a Multi-Fuel Sofc-Stirling Hybrid Configuration

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2012-01-01

    A novel hybrid system ( kWe) for an average family house including heating is proposed. The system investigated, contains of a Solid Oxide Fuel Cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle is fed to the bottoming Stirling engine wherein additional power...... efficiency compared with the stand alone Stirling engine or SOFC plant. For the SOFC and Stirling combined configuration, the overall power production has increased by about 10% compared to the stand alone SOFC plant. System efficiencies of about 60% are achieved which is remarkable for such small plant...

  17. A New Design Strategy for Efficient Thermally Activated Delayed Fluorescence Organic Emitters: From Twisted to Planar Structures

    KAUST Repository

    Chen, Xiankai

    2017-10-17

    In the traditional molecular design of thermally activated delayed fluorescence (TADF) emitters composed of electron-donor and electron-acceptor moieties, achieving a small singlet-triplet energy gap (ΔEST ) in strongly twisted structures usually translates into a small fluorescence oscillator strength, which can significantly decrease the emission quantum yield and limit efficiency in organic light-emitting diode devices. Here, based on the results of quantum-chemical calculations on TADF emitters composed of carbazole donor and 2,4,6-triphenyl-1,3,5-triazine acceptor moieties, a new strategy is proposed for the molecular design of efficient TADF emitters that combine a small ΔEST with a large fluorescence oscillator strength. Since this strategy goes beyond the traditional framework of structurally twisted, charge-transfer type emitters, importantly, it opens the way for coplanar molecules to be efficient TADF emitters. Here, a new emitter, composed of azatriangulene and diphenyltriazine moieties, is theoretically designed, which is coplanar due to intramolecular H-bonding interactions. The synthesis of this hexamethylazatriangulene-triazine (HMAT-TRZ) emitter and its preliminary photophysical characterizations point to HMAT-TRZ as a potential efficient TADF emitter.

  18. Effect of Lanthanum-Strontium Cathode Current-Collecting Layer on the Performance of Anode Supported Type Planar Solid Oxide Fuel Cells

    Science.gov (United States)

    Park, Sun-Young; Ji, Ho-Il; Kim, Hae-Ryoung; Yoon, Kyung Joong; Son, Ji-Won; Lee, Hae-Weon; Lee, Jong-Ho

    2013-07-01

    We applied screen-printed (La,Sr)CoO3 as a current-collecting layer of planar type unit-cell for lower temperature operation of SOFCs. In this study the effects of the cathode current-collecting layer on the performance of unit cell and symmetric half cell were investigated via AC and DC polarization experiments. According to our investigation, appropriately controlled current collecting layer was very effective to enhance the unit cell performance by reducing not only the ohmic resistance but also the polarization losses of SOFC cathode.

  19. Effects of Pretreatment Methods on Electrodes and SOFC Performance

    Directory of Open Access Journals (Sweden)

    Guo-Bin Jung

    2014-06-01

    Full Text Available Commercially available tapes (anode, electrolyte and paste (cathode were choosen to prepare anode-supported cells for solid oxide fuel cell applications. For both anode-supported cells or electrolyte-supported cells, the anode needs pretreatment to reduce NiO/YSZ to Ni/YSZ to increase its conductivity as well as its catalytic characteristics. In this study, the effects of different pretreatments (open-circuit, closed-circuit on cathode and anodes as well as SOFC performance are investigated. To investigate the influence of closed-circuit pretreatment on the NiO/YSZ anode alone, a Pt cathode is utilized as reference for comparison with the LSM cathode. The characterization of the electrical resistance, AC impedance, and SOFC performance of the resulting electrodes and/or anode-supported cell were carried out. It’s found that the influence of open-circuit pretreatment on the LSM cathode is limited. However, the influence of closed-circuit pretreatment on both the LSM cathode and NiO/YSZ anode and the resulting SOFC performance is profound. The effect of closed-circuit pretreatment on the NiO/YSZ anode is attributed to its change of electronic/pore structure as well as catalytic characteristics. With closed-circuit pretreatment, the SOFC performance improved greatly from the change of LSM cathode (and Pt reference compared to the Ni/YSZ anode.

  20. Simulation of SOFCs based power generation system using Aspen

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2017-12-01

    Full Text Available This study presents a thermodynamic Aspen simulation model for Solid Oxide Fuel Cells, SOFCs, based power generation system. In the first step, a steady-state SOFCs system model was developed. The model includes the electrochemistry and the diffusion phenomena. The electrochemical model gives good agreement with experimental data in a wide operating range. Then, a parametric study has been conducted to estimate effects of the oxygen to carbon ratio, O/C, on reformer temperature, fuel cell temperature, fuel utilization, overall fuel cell performance, and the results are discussed in this paper. In the second step, a dynamic analysis of SOFCs characteristic has been developed. The aim of dynamic modelling was to find the response of the system against the fuel utilization and the O/C ratio variations. From the simulations, it was concluded that both developed models in the steady and dynamic state were reasonably accurate and can be used for system level optimization studies of the SOFC based power generation system.

  1. Investigation of Performance of SCN-1 Pure Glass as Sealant Used in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2010-03-01

    As its name implies, self-healing glass seal has the potential of restoring its mechanical properties upon being reheated to stack operating temperature, even when it has experienced some cooling induced damage/crack at room temperature. Such a self-healing feature is desirable for achieving high seal reliability during thermal cycling. On the other hand, self-healing glass is also characterized by its low mechanical stiffness and high creep rate at the typical operating temperature of SOFCs. Therefore, from a design’s perspective, it is important to know the long term geometric stability and thermal mechanical behaviors of the self-healing glass under the stack operating conditions. These predictive capabilities will guide the design and optimization of a reliable sealing system that potentially utilizes self-healing glass as well as other ceramic seal components in achieving the ultimate goal of SOFC. In this report, we focused on predicting the effects of various generic seal design parameters on the stresses in the seal. For this purpose, we take the test cell used in the leakage test for compliant glass seals conducted in PNNL as our initial modeling geometry. The effect of the ceramic stopper on the geometry stability of the self-healing glass sealants is studied first. Then we explored the effect of various interfaces such as stopper and glass, stopper and PEN, as well stopper and IC plate, on the geometry stability and reliability of glass during the operating and cooling processes.

  2. The modeling and simulation of thermal based modified solid oxide fuel cell (SOFC for grid-connected systems

    Directory of Open Access Journals (Sweden)

    Ayetül Gelen

    2015-05-01

    Full Text Available This paper presents a thermal based modified dynamic model of a Solid Oxide Fuel Cell (SOFC for grid-connected systems. The proposed fuel cell model involves ohmic, activation and concentration voltage losses, thermal dynamics, methanol reformer, fuel utilization factor and power limiting module. A power conditioning unit (PCU, which consists of a DC-DC boost converter and a DC-AC voltage-source inverter (VSI, their controller, transformer and filter, is designed for grid-connected systems. The voltage-source inverter with six Insulated Gate Bipolar Transistor (IGBT switches inverts the DC voltage that comes from the converter into a sinusoidal voltage synchronized with the grid. The simulations and modeling of the system are developed on Matlab/Simulink environment. The performance of SOFC with converter is examined under step and random load conditions. The simulation results show that the designed boost converter for the proposed thermal based modified SOFC model has fairly followed different DC load variations. Finally, the AC bus of 400 Volt and 50 Hz is connected to a single-machine infinite bus (SMIB through a transmission line. The real and reactive power managements of the inverter are analyzed by an infinite bus system. Thus, the desired nominal values are properly obtained by means of the inverter controller.

  3. Study of a hybrid system using solid oxide fuel cells (SOFC) and gas turbine; Estudo de um sistema hibrido empregando celula de combustivel de oxido solido (SOFC) e turbina a gas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Antonio Carlos Caetano de; Gallo, Giulliano Batelochi; Silveira, Jose Luz [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia], e-mail: caetano@feg.unesp.br

    2004-07-01

    In this paper a hybrid solid oxide fuel cell (SOFC) system, applying a combined cycle using gas turbine for rational decentralized energy production is analyzed. The relative concepts about the fuel cell are presented, followed by some chemical and technical information such as the change of Gibbs free energy in isothermal fuel oxidation directly into electricity. This represents a very high fraction of the lower heating value (LHV) of a hydrocarbon fuel. In the next step a methodology for the study of SOFC and gas turbine system is developed, considering the electricity and steam production for a hospital. This methodology is applied to energetic analysis. Natural gas is considered as a fuel. A Sankey Diagram shows that the hybrid SOFC system is a good opportunity to strengthen the decentralized energy production in Brazil. It is necessary to consider that the cogeneration in this version also is a good technical alternative, demanding special methods of design, equipment selection and contractual deals associated to electricity and fuel supply. (author)

  4. Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

    Science.gov (United States)

    White, B. D.; Kesler, O.; Rose, Lars

    Air plasma spraying has been used to produce porous composite cathodes containing (La 0.8Sr 0.2) 0.98MnO 3- y (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high.

  5. Air plasma spray processing and electrochemical characterization of SOFC composite cathodes

    Energy Technology Data Exchange (ETDEWEB)

    White, B.D. [Department of Mechanical Engineering, The University of British Columbia, 2054-6250 Applied Sciences Lane, Vancouver, British Columbia (Canada); Kesler, O. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario (Canada); Rose, Lars [Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, British Columbia (Canada); National Research Council (Canada)

    2008-03-15

    Air plasma spraying has been used to produce porous composite cathodes containing (La{sub 0.8}Sr{sub 0.2}){sub 0.98}MnO{sub 3-y} (LSM) and yttria-stabilized zirconia (YSZ) for use in solid oxide fuel cells (SOFCs). Preliminary investigations focused on determining the range of plasma conditions under which each of the individual materials could be successfully deposited. A range of conditions was thereby determined that was suitable for the deposition of a composite cathode from pre-mixed LSM and YSZ powders. A number of composite cathodes were produced using different combinations of parameter values within the identified range according to a Uniform Design experimental grid. Coatings were then characterized for composition and microstructure using EDX and SEM. As a result of these tests, combinations of input parameter values were identified that are best suited to the production of coatings with microstructures appropriate for use in SOFC composite cathodes. A selection of coatings representative of the types of observed microstructures were then subjected to electrochemical testing to evaluate the performance of these cathodes. From these tests, it was found that, in general, the coatings that appeared to have the most suitable microstructures also had the highest electrochemical performances, provided that the deposition efficiency of both phases was sufficiently high. (author)

  6. A Fuzzy-Based PI Controller for Power Management of a Grid-Connected PV-SOFC Hybrid System

    Directory of Open Access Journals (Sweden)

    Shivashankar Sukumar

    2017-10-01

    Full Text Available Solar power generation is intermittent in nature. It is nearly impossible for a photovoltaic (PV system to supply power continuously and consistently to a varying load. Operating a controllable source like a fuel cell in parallel with PV can be a solution to supply power to variable loads. In order to coordinate the power supply from fuel cells and PVs, a power management system needs to be designed for the microgrid system. This paper presents a power management system for a grid-connected PV and solid oxide fuel cell (SOFC, considering variation in the load and solar radiation. The objective of the proposed system is to minimize the power drawn from the grid and operate the SOFC within a specific power range. Since the PV is operated at the maximum power point, the power management involves the control of SOFC active power where a proportional and integral (PI controller is used. The control parameters of the PI controller Kp (proportional constant and Ti (integral time constant are determined by the genetic algorithm (GA and simplex method. In addition, a fuzzy logic controller is also developed to generate appropriate control parameters for the PI controller. The performance of the controllers is evaluated by minimizing the integral of time multiplied by absolute error (ITAE criterion. Simulation results showed that the fuzzy-based PI controller outperforms the PI controller tuned by the GA and simplex method in managing the power from the hybrid source effectively under variations of load and solar radiation.

  7. Niobium-doped strontium titanates as SOFC anodes

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L. Reine

    2008-01-01

    been synthesized with a recently developed modified glycine-nitrate process. The synthesized powders have been calcined and sintered in air or in 9% H(2) / N(2) between 800 - 1400 degrees C. After calcination the samples were single phase Nb-doped strontium titanate with grain sizes of less than 100 nm...... in diameter on average. The phase purity, defect structure, and microstructure of the materials have been analyzed with SEM, XRD, and TGA. The electrical conductivity of the Nb-doped titanate decreased with increasing temperature and showed a phonon scattering conduction mechanism with sigma > 120 S...... ability of the Nb-doped titanates to be used as a part of a SOFC anode. However, the catalytic activity of the materials was not sufficient and it needs to be improved if titanate based materials are to be realized as constituents in SOFC anodes....

  8. In-Situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes

    Science.gov (United States)

    2010-12-28

    DATES COVERED (From - To) 1/29/10-9/30/10 4. TITLE AND SUBTITLE In situ optical studies of oxidation/reduction kinetics on SOFC cermet anodes 5a...0572 In-situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes Department of Chemistry and Biochemistry Montana State University...of Research In-situ Optical Studies of Oxidation/Reduction Kinetics on SOFC Cermet Anodes Principal Investigator Robert Walker Organization

  9. Thermal plasma spraying for SOFCs: Applications, potential advantages, and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Rob; Wang, Zhenwei; Jankovic, Jasna; Yick, Sing; Maric, Radenka; Ghosh, Dave [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Kesler, Olivera [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4 (Canada); Rose, Lars [National Research Council Institute for Fuel Cell Innovation, 4250 Wesbrook Mall, Vancouver, BC V6T 1W5 (Canada); Department of Materials Engineering, University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4 (Canada)

    2007-07-10

    In this article, the applications, potential advantages, and challenges of thermal plasma spray (PS) processing for nanopowder production and cell fabrication of solid oxide fuel cells (SOFCs) are reviewed. PS processing creates sufficiently high temperatures to melt all materials fed into the plasma. The heated material can either be quenched into oxide powders or deposited as coatings. This technique has been applied to directly deposit functional layers as well as nanopowder for SOFCs application. In particularly, low melting point and highly active electrodes can be directly fabricated on zirconia-based electrolytes. This is a simple processing technique that does not require the use of organic solvents, offering the opportunity for flexible adjustment of process parameters, and significant time saving in production of the cell and cost reduction compared with tape casting, screen printing and sintering processing steps. Most importantly, PS processing shows strong potential to enable the deposition of metal-supported SOFCs through the integrated fabrication of membrane-electrode assemblies (MEA) on porous metallic substrates with consecutive deposition steps. On the other hand, the application of PS processing to produce SOFCs faces some challenges, such as insufficient porosity of the electrodes, the difficulty of obtaining a thin (<10 {mu}m) and dense electrolyte layer. Fed with H{sub 2} as the fuel gas and oxygen as the oxidant gas, the plasma sprayed cell reached high power densities of 770 mW cm{sup -2} at 900 C and 430 mW cm{sup -2} at 800 C at a cell voltage of 0.7 V. (author)

  10. Manufacture of SOFC electrodes by wet powder spraying

    Energy Technology Data Exchange (ETDEWEB)

    Wilkenhoener, R.; Mallener, W.; Buchkremer, H.P. [Forschungszentrum Juelich GmbH (Germany)] [and others

    1996-12-31

    The reproducible and commercial manufacturing of electrodes with enhanced electrochemical performance is of central importance for a successful technical realization of Solid Oxide Fuel Cell (SOFC) systems. The route of electrode fabrication for the SOFC by Wet Powder Spraying (WPS) is presented. Stabilized suspensions of the powder materials for the electrodes were sprayed onto a substrate by employing a spray gun. After drying of the layers, binder removal and sintering are performed in one step. The major advantage of this process is its applicability for a large variety of materials and its flexibility with regard to layer shape and thickness. Above all, flat or curved substrates of any size can be coated, thus opening up the possibility of {open_quotes}up-scaling{close_quotes} SOFC technology. Electrodes with an enhanced electrochemical performance were developed by gradually optimizing the different process steps. For example an optimized SOFC cathode of the composition La{sub 0.65}Sr{sub 0.3}MnO{sub 3} with 40% 8YSZ showed a mean overpotential of about -50 mV at a current density of -0.8 A/cm{sup 2}, with a standard deviation amounting to 16 mV (950{degrees}C, air). Such optimized electrodes can be manufactured with a high degree of reproducibility, as a result of employing a computer-controlled X-Y system for moving the spray gun. Several hundred sintered composites, comprising the substrate anode and the electrolyte, of 100x 100 mm{sup 2} were coated with the cathode by WPS and used for stack integration. The largest manufactured electrodes were 240x240 mm{sup 2}, and data concerning their thickness homogeneity and electrochemical performance are given.

  11. Transient performance of integrated SOFC system including spatial temperature control

    OpenAIRE

    Mueller, F; Fardadi, M; Shaffer, B; Brouwer, J; Jabbari, F

    2010-01-01

    Spatial temperature feedback control has been developed for a simulated integrated non-pressurized simple cycle solid oxide fuel cell (SOFC) system. The fuel cell spatial temperature feedback controller is based on (1) feed-forward set-points that minimize temperature variation in the fuel cell electrode-electrolyte solid temperature profile for the system operating power range, and (2) decentralized proportional-integral based feedback to maintain the fuel cell spatial temperature profile du...

  12. Innovative Seals for Solid Oxide Fuel Cells (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Raj

    2008-06-30

    A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

  13. Continued research, development and test of SOFC Technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2008-09-15

    The aim of the project was to further develop the SOFC cell and stack technology and drive down manufacturing costs in order to accomplish the performance and economic targets set forward in the SOFC road map, which has been developed in collaboration with the national Danish SOFC Strategy group. The project was divided into four parts. Part 1, Continued cell development covered the successful development of larger cells with a 500 cm2 footprint. Part 2, Cell manufacturing covered the production of 9.859 equivalents (12x12 cm2 standard cells) that were used in the stacks for demonstration projects (EFP 33033-0050)and for in-house research, development and testing in this project. Part 3, Continued stack development covered the successful test of a 3 kW{sub e} stack as well as the planning of a >8.000 hours stack test with new stack technology. The >8.000 hours test that started after the end date for this project will last for 12 months and be reported in the PSO 2008-1-010049 project. Part 4, Stack manufacturing covered a number of small stacks for in-house research, development and testing. (auther)

  14. Recent activities of SOFC research development and demonstration in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yokokawa, Harumi [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan); Tokyo City Univ. (Japan). Advanced Research Labs.

    2010-07-01

    Currently Japanese efforts in developing the SOFC systems have two major targets; one is small SOFC cogeneration systems for residential houses or small business sites, the other being the SOFC-GT hybrid systems with an aim at larger stationary applications. The former activity exhibits impressively rapid progress in system development and demonstration in actual residential environment. On the other hand, the development of hybrid systems is not so rapid but successfully has continued to test the operation of the hybrid system in a 200 kW class. The common requirement for both applications is high durability such as 40,000-100,000 of life. To achieve a long life simultaneously with reasonably low price and high efficiency the NEDO project is going on to promote the cooperation among the stack developers, national institute and universities. To achieve well organized cooperation, it is highly required to create mutual reliance between industry and academic organizations. After several years' experience, progress has been made in maturing cooperation and in leading to many new insights into physicochemical understanding of degradation phenomena. Some of them will be reported. (orig.)

  15. Development of 10kW SOFC module

    Energy Technology Data Exchange (ETDEWEB)

    Hisatome, N.; Nagata, K. [Mitsubishi Heavy Industries, Ltd., Nagasaki (Japan); Kakigami, S. [Electric Power Development Co., Inc., Tokyo (Japan)] [and others

    1996-12-31

    Mitsubishi Heavy industries, Ltd. (MHI) has been developing tubular type Solid Oxide Fuel Cells (SOFC) since 1984. A 1 kW module of SOFC has been continuously operated for 3,000 hours with 2 scheduled thermal cycles at Electric Power Development Co., Inc. (EPDC) Wakamatsu Power Station in 1993. We have obtained of 34% (HHV as H{sub 2}) module efficiency and deterioration rate of 2% Per 1,000 hours in this field test. As for next step, we have developed 10 kW module in 1995. The 10 kW module has been operated for 5,000 hours continuously. This module does not need heating support to maintain the operation temperature, and the module efficiency was 34% (HHV as H{sub 2}). On the other hand, we have started developing the technology of pressurized SOFC. In 1996, pressurized MW module has been tested at MHI Nagasaki Shipyard & Machinery, Works. We are now planning the development of pressurized 10 kW module.

  16. Numerical investigation of a novel burner to combust anode exhaust gases of SOFC stacks

    Directory of Open Access Journals (Sweden)

    Pianko-Oprych Paulina

    2017-09-01

    Full Text Available The aim of the present study was a numerical investigation of the efficiency of the combustion process of a novel concept burner under different operating conditions. The design of the burner was a part of the development process of a complete SOFC based system and a challenging combination of technical requirements to be fulfilled. A Computational Fluid Dynamics model of a non-premixed burner was used to simulate combustion of exhaust gases from the anode region of Solid Oxide Fuel Cell stacks. The species concentrations of the exhaust gases were compared with experimental data and a satisfactory agreement of the conversion of hydrocarbons was obtained. This validates the numerical methodology and also proves applicability of the developed approach that quantitatively characterized the interaction between the exhaust gases and burner geometry for proper combustion modelling. Thus, the proposed CFD approach can be safely used for further numerical optimisation of the burner design.

  17. Development of Robust Metal-Supported SOFCs and Stack Components in EU METSAPP Consortium

    DEFF Research Database (Denmark)

    Sudireddy, Bhaskar Reddy; Nielsen, Jimmi; Persson, Åsa Helen

    2017-01-01

    METSAPP project has been executed with an overall aim of developing advanced metal-supported cells and stacks based on a robust, reliable and up-scalable technology. During the project, oxidation resistant nanostructured anodes based on modified SrTiO3 were developed and integrated into MS...... and best performance and stability combination was observed with doped SrTiO3 based anode designs. Furthermore, numerical models to understand the corrosion behavior of the MS-SOFCs were developed and validated. Finally, the cost effective concept of coated metal interconnects was developed, which resulted...... in 90% reduction in Cr evaporation, three times lower Cr2O3 scale thickness and increased lifetime. The possibility of assembling these cells into two radically different stack designs was demonstrated....

  18. Utilization of gases from biomass gasification in a reforming reactor coupled to an integrated planar solid oxide fuel cell: Simulation analysis

    Directory of Open Access Journals (Sweden)

    Costamagna Paola

    2004-01-01

    Full Text Available One of the high-efficiency options currently under study for a rational employment of hydrogen are fuel cells. In this scenario, the integrated planar solid oxide fuel cell is a new concept recently proposed by Rolls-Royce. The basic unit of a modular plant is the so called "strip", containing an electro-chemical reactor formed by a number of IP-SOFC modules, and a reforming reactor. For a better under standing of the behavior of a system of this kind, a simulation model has been set up for both the electrochemical reactor and the reformer; both models follow the approach typically employed in the simulation of chemical reactors, based on the solution of mass and energy balances. In the case of the IP-SOFC electro chemical reactor, the model includes the calculation of the electrical resistance of the stack (that is essentially due to ohmic losses, activation polar is action and mass transport limitations, the mass balances of the gaseous flows, the energy balances of gaseous flows (anodic and cathodic and of the solid. The strip is designed in such a way that the reaction in the reforming reactor is thermally sustained by the sensible heat of the hot air exiting the electrochemical section; this heat exchange is taken into account in the model of the reformer, which includes the energy balance of gaseous flows and of the solid structure. Simulation results are reported and discussed for both the electrochemical reactor in stand-alone configuration (including comparison to experimental data in a narrow range of operating conditions and for the complete strip.

  19. Diesel CPO for SOFC. Development of a cold-flame assisted CPO reactor coupled to a SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, H.A.J.; Ouweltjes, J.P.; Nyqvist, R.G. [ECN Hydrogen and Clean Fossil Fuels, Petten (Netherlands)

    2009-07-15

    Within the research program 'Reforming of liquid fuels for fuel-cells', ECN started a project on the development of a diesel CPO (catalytic partial oxidation) reformer for SOFC (solid oxide fuel cell) in 2005. The application in mind is a small scale (5kWe) diesel fed auxiliary power unit (APU). The goal of the project is to develop the technology required to transform a liquid logistic fuel into a reformat suitable for the operation of a SOFC. The emphasis of this work is on the development of a cold-flame assisted evaporator/mixer coupled to a catalytic CPO reformer. The application of cold-flame evaporation and mixing allows the reformat to be directly fed to the SOFC without further heating or cooling. Moreover, once cold-flames are ignited and stabilized, pre-heating of the air and fuel becomes obsolete. These aspects justify the development described in this report. In the cold-flame evaporator/mixer, the cold-flames are stabilized by means of a recirculation tube. The momentum of the fuel spray of the nozzle induces the required recirculation. The cold flame evaporator/mixer was coupled to a catalytic reformer reactor, transforming the hydrocarbon+air feed into a CO+H2 rich reformate. The reformer was coupled to a SOFC to be able to verify the quality of the reformat obtained with this reformer. The SOFC therefore served as an analysis tool. Characteristically, the reformat was held at 800C all the way towards the SOFC. For this, high temperature flange connections and steel-ceramic expansion connections were successfully applied. It is demonstrated that cold-flame evaporation of liquid fuels is a feasible means of feed preparation for a catalytic reforming reactor. The quality of the resulting reformat is adequate to be fed to the SOFC. The reformat quality, however, decreased with time-on-stream due to fouling of the reformer by carbon-depositions. These carbon-depositions were essentially located on the fuel injector, which is the coldest part

  20. Investigation of methane steam reforming in planar porous support of solid oxide fuel cell

    International Nuclear Information System (INIS)

    Yang Yongping; Du Xiaoze; Yang Lijun; Huang Yuan; Xian Haizhen

    2009-01-01

    Adopting the porous support in integrated-planar solid oxide fuel cell (IP-SOFC) can reduce the operating temperature by reducing thickness of electrolyte layer, and also, provide internal reforming environment for hydrogen-rich fuel gas. The distributions of reactant and product components, and temperature of methane steam reforming for IP-SOFC were investigated by the developed physical and mathematical model with thermodynamic analysis, in which eleven possible reaction mechanisms were considered by the source terms and Arrhenius relationship. Numerical simulation of the model revealed that the progress of reforming reaction and the distribution of the product, H 2 , were influenced by the operating conditions, included that of temperature, ratio of H 2 O and CH 4 , as well as by the porosity of the supporting material. The simulating results indicate that the methane conversion rate can reach its maximum value under the operating temperature of 800 deg. C and porosity of ε = 0.4, which rather approximate to the practical operating conditions of IP-SOFC. In addition, characteristics of carbon deposition on surface of catalyst were discussed under various operating conditions and configuration parameters of the porous support. The present works provided some theoretical explanations to the numerous experimental observations and engineered practices

  1. Beyond level planarity

    NARCIS (Netherlands)

    Angelini, P.; Da Lozzo, G.; Di Battista, G.; Frati, F.; Patrignani, M.; Rutter, I.; Hu, Y.; Nöllenburg, M.

    2016-01-01

    In this paper we settle the computational complexity of two open problems related to the extension of the notion of level planarity to surfaces different from the plane. Namely, we show that the problems of testing the existence of a level embedding of a level graph on the surface of the rolling

  2. HP Ge planar detectors

    International Nuclear Information System (INIS)

    Gornov, M.G.; Gurov, Yu.B.; Soldatov, A.M.; Osipenko, B.P.; Yurkowski, J.; Podkopaev, O.I.

    1989-01-01

    Parameters of planar detectors manufactured of HP Ge are presented. The possibilities to use multilayer spectrometers on the base of such semiconductor detectors for nuclear physics experiments are discussed. It is shown that the obtained detectors including high square ones have spectrometrical characteristics close to limiting possible values. 9 refs.; 3 figs.; 1 tab

  3. Full Ceramic Fuel Cells Based on Strontium Titanate Anodes, An Approach Towards More Robust SOFCs

    DEFF Research Database (Denmark)

    Holtappels, Peter; Irvine, J.T.S.; Iwanschitz, B.

    2013-01-01

    The persistent problems with Ni-YSZ cermet based SOFCs, with respect to redox stability and tolerance towards sulfur has stimulated the development of a full ceramic cell based on strontium titanate(ST)- based anodes and anode support materials, within the EU FCH JU project SCOTAS-SOFC. Three...

  4. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    DEFF Research Database (Denmark)

    Rabbani, Raja Abid; Rokni, Masoud

    2014-01-01

    A hybrid fuel cell system (~10 kWe) for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC) on top of a Polymer Electrolyte Fuel Cell (PEFC). Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simul...

  5. Improvement of SOFC electrodes using mixed ionic-electronic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Y.; Hishinuma, M. [Tokyo Gas Co., Ltd. (Japan)

    1996-12-31

    Since the electrode reaction of SOFC is limited to the proximity of a triple phase boundary (TPB), the local current density at the electrode and electrolyte interface is larger than mean current density, which causes large ohmic and electrode polarization. This paper describes an application of mixed ionic-electronic conductors to reduce such polarization by means of (1) enhancing ionic conductivity of the electrolyte surface layer by coating a high ionic conductors, and (2) reducing the local current density by increasing the electrochemically active sites.

  6. How to draw a planarization

    NARCIS (Netherlands)

    Bläsius, T.; Radermacher, M.; Rutter, I.; Steffen, B.; Baier, C.; van den Brand, M.; Eder, J.; Hinchey, M.; Margaria, T.

    2017-01-01

    We study the problem of computing straight-line drawings of non-planar graphs with few crossings. We assume that a crossing-minimization algorithm is applied first, yielding a planarization, i.e., a planar graph with a dummy vertex for each crossing, that fixes the topology of the resulting drawing.

  7. Evaluation of Cathode Air Flow Transients in a SOFC/GT Hybrid System Using Hardware in the Loop Simulation.

    Science.gov (United States)

    Zhou, Nana; Yang, Chen; Tucker, David

    2015-02-01

    Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system can be improved by effective management and control of the cathode airflow. The disturbances of the cathode airflow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments, using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The dynamic responses of the fuel cell component and hardware component of the hybrid system were studied in this paper.

  8. Rational design and characterization of high-efficiency planar A–π–D–π–A type electron donors in small molecule organic solar cells: A quantum chemical approach

    International Nuclear Information System (INIS)

    Wang, Dongmei; Ding, Weilu; Geng, Zhiyuan; Wang, Li; Geng, Yun; Su, Zhongmin; Yu, Hailing

    2014-01-01

    Taking the reported donor DR3TBDT as reference, a series of A–π–D–π–A type donor molecules involving different planar donor cores were designed and investigated by using density functional theory (DFT)/time-dependent DFT methods. Preliminary calculations on geometries, energy levels and spectrum properties show that four of the designed molecules (4, 5, 12 and 13) could become potential donor replacements of DR3TBDT due to their good planarity, larger light harvesting efficiencies and similar exciton migration capability. Additionally, several factors influencing on short-circuit current density (J sc ) were analyzed by in-depth quantum chemical investigations on the transition density matrix, charge transfer indexes, exciton binding energy and Gibbs free energy loss in charge dissociation process. Comparative analyses demonstrate that 4 with indaceno[1,2-b:5,6-b′]dithiophene donor core has more significant electron transfer character and favorable exciton dissociation capability for enhancing the J sc , and would be potentially promising donor material in organic solar cells. - Graphical abstract: Display Omitted - Highlights: • A series of A–π–D–π–A type donors with different donor core for OSC were designed. • The relationship between donor properties and device performance is explored by DFT. • An In-depth quantum chemical investigation on the affecting factors on J sc . • The efficiency of new donor 4 may surpass the reported donor DR3TBDT

  9. Development of planar detectors with active edge

    International Nuclear Information System (INIS)

    Povoli, M.; Bagolini, A.; Boscardin, M.; Dalla Betta, G.-F.; Giacomini, G.; Vianello, E.; Zorzi, N.

    2011-01-01

    We report on the first batch of planar active edge sensors fabricated at Fondazione Bruno Kessler (Trento, Italy) on the way to the development of full 3D detectors with active edges. The main design and technological aspects are reported, along with selected results from the electrical characterization of detectors and test structures.

  10. Development of planar detectors with active edge

    Energy Technology Data Exchange (ETDEWEB)

    Povoli, M., E-mail: povoli@disi.unitn.it [Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, Via Sommarive, 14, I-38123 Povo di Trento (Italy); INFN, Sezione di Padova (Gruppo Collegato di Trento) (Italy); Bagolini, A.; Boscardin, M. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy); Dalla Betta, G.-F. [Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, Via Sommarive, 14, I-38123 Povo di Trento (Italy); INFN, Sezione di Padova (Gruppo Collegato di Trento) (Italy); Giacomini, G.; Vianello, E.; Zorzi, N. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy)

    2011-12-01

    We report on the first batch of planar active edge sensors fabricated at Fondazione Bruno Kessler (Trento, Italy) on the way to the development of full 3D detectors with active edges. The main design and technological aspects are reported, along with selected results from the electrical characterization of detectors and test structures.

  11. High-Temperature Desulfurization of Heavy Fuel-Derived Reformate Gas Streams for SOFC Applications

    Science.gov (United States)

    Flytzani-Stephanopoulos, Maria; Surgenor, Angela D.

    2007-01-01

    Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.

  12. Routed planar networks

    Directory of Open Access Journals (Sweden)

    David J. Aldous

    2016-04-01

    Full Text Available Modeling a road network as a planar graph seems very natural. However, in studying continuum limits of such networks it is useful to take {\\em routes} rather than {\\em edges} as primitives. This article is intended to introduce the relevant (discrete setting notion of {\\em routed network} to graph theorists. We give a naive classification of all 71 topologically different such networks on 4 leaves, and pose a variety of challenging research questions.

  13. Tracking Oxygen Vacancies in Thin Film SOFC Cathodes

    Science.gov (United States)

    Leonard, Donovan; Kumar, Amit; Jesse, Stephen; Kalinin, Sergei; Shao-Horn, Yang; Crumlin, Ethan; Mutoro, Eva; Biegalski, Michael; Christen, Hans; Pennycook, Stephen; Borisevich, Albina

    2011-03-01

    Oxygen vacancies have been proposed to control the rate of the oxygen reduction reaction and ionic transport in complex oxides used as solid oxide fuel cell (SOFC) cathodes [1,2]. In this study oxygen vacancies were tracked, both dynamically and statically, with the combined use of scanned probe microscopy (SPM) and scanning transmission electron microscopy (STEM). Epitaxial films of La 0.8 Sr 0.2 Co O3 (L SC113) and L SC113 / LaSrCo O4 (L SC214) on a GDC/YSZ substrate were studied, where the latter showed increased electrocatalytic activity at moderate temperature. At atomic resolution, high angle annular dark field STEM micrographs revealed vacancy ordering in L SC113 as evidenced by lattice parameter modulation and EELS studies. The evolution of oxygen vacancy concentration and ordering with applied bias and the effects of bias cycling on the SOFC cathode performance will be discussed. Research is sponsored by the of Materials Sciences and Engineering Division, U.S. DOE.

  14. Parametric exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack through finite-volume model

    International Nuclear Information System (INIS)

    Calise, F.; Ferruzzi, G.; Vanoli, L.

    2009-01-01

    This paper presents a very detailed local exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack. In particular, a complete parametric analysis has been carried out, in order to assess the effects of the synthesis/design parameters on the local irreversibilities in the components of the stack. A finite-volume axial-symmetric model of the tubular internal reforming Solid Oxide Fuel Cell stack under investigation has been used. The stack consists of: SOFC tubes, tube-in-tube pre-reformer and tube and shell catalytic burner. The model takes into account the effects of heat/mass transfer and chemical/electrochemical reactions. The model allows one to predict the performance of a SOFC stack once a series of design and operative parameters are fixed, but also to investigate the source and localization of inefficiency. To this scope, an exergy analysis was implemented. The SOFC tube, the pre-reformer and the catalytic burner are discretized along their longitudinal axes. Detailed models of the kinetics of the reforming, catalytic combustion and electrochemical reactions are implemented. Pressure drops, convection heat transfer and overvoltages are calculated on the basis of the work previously developed by the authors. The heat transfer model includes the contribution of thermal radiation, so improving the models previously used by the authors. Radiative heat transfer is calculated on the basis of the slice-to-slice configuration factors and corresponding radiosities. On the basis of this thermochemical model, an exergy analysis has been carried out, in order to localize the sources and the magnitude of irreversibilities along the components of the stack. In addition, the main synthesis/design variables were varied in order to assess their effect on the exergy destruction within the component to which the parameter directly refers ('endogenous' contribution) and on the exergy destruction of all remaining components ('exogenous' contribution). Then, this analysis

  15. Three dimensional analysis of planar solid oxide fuel cell stack considering radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.; Inui, Y.; Urata, A.; Kanno, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)

    2007-05-15

    The authors have been engaged in numerical simulations of the planar type solid oxide fuel cell (SOFC) to make clear the dependence of the cell performance on its operating conditions. Up to now, the authors have already developed the simulation codes for the one channel region and the single cell plate in its cell stack. To calculate accurately the effect of radiation heat transfer from the cell stack surfaces, however, a code that can treat the whole cell stack is necessary. In the present study, therefore, the authors newly develop a three dimensional simulation code of the planar SOFC stack, and the detailed effect of the radiation heat transfer is investigated. It is made clear that the conventional codes are sufficiently accurate, and the newly developed whole cell stack code is not inevitable to predict the maximum cell temperature. This is because the thermal conductivity of the cell materials made of ceramics is very small, and the central part of the cell stack is almost free from the influence of radiation heat transfer. On the other hand, the stack simulation is needed to calculate accurately the cell voltage because the radiation heat transfer reduces it when the ambient temperature is low. The bad influence of low ambient temperature on the voltage is, however, small and relatively high voltage is obtained even when the ambient temperature is very low. (author)

  16. Manufacturing of Electrolyte and Cathode Layers SOFC Using Atmospheric Spraying Method and Its Characterization

    Directory of Open Access Journals (Sweden)

    S. Sulistyo

    2012-12-01

    Full Text Available The use of Solid Oxide Fuel Cell (SOFC has created various interest in many parties, due to its capability to convert gases into electricity. The main requirement of SOFC cell components is to be produced as thin as possible to minimize the losses of electrical resistance, as well as able to support internal and external loads. This paper discusses the procedure of making a thin electrolyte layer, as well as a porous thin layer cathode using atmospheric spraying technique. The procedure of spraying was in room temperature with the process of sintering at temperature of 13500 C held for 3 hours. The SOFC characterization of electrolyte and cathode microstructure was determined by using the SEM, FESEM, XRD and impedance spectroscopy, to measure the impedance of SOFC cells. The results show that the thickness of thin layer electrolyte and porous cathode obtained of about 20 µm and 4 µm, respectively. Also the SOFC cell impedance was measured of 2.3726 x 106 Ω at room temperature. The finding also demonstrated that although the materials (anode, cathode and electrolyte possess different coefficient thermal expansion, there was no evidence of flaking layers which seen the materials remain intact. Thus, the atmospheric spraying method can offer an alternative method to manufacturing of SOFC thin layer electrolyte and cathode. [Key words: SOFC; spraying method; electrolyte; cathode

  17. Municipal Solid Waste Gasification Plant Integrated With SOFC and Gas Turbine

    DEFF Research Database (Denmark)

    Bellomare, Filippo; Rokni, Masoud

    2012-01-01

    An interesting source of producing energy with low pollutants emission and reduced environmental impact are the biomasses; particularly using Municipal Solid Waste (MSW) as fuel, can be a competitive solution not only to produce energy with negligible costs but also to decrease the storage...... in landfills. A Municipal Solid Waste Gasification Plant Integrated with Solid Oxide Fuel Cell (SOFC) and Gas Turbine (GT) has been studied and the plant is called IGSG (Integrated Gasification SOFC and GT). Gasification plant is fed by MSW to produce syngas by which the anode side of a SOFC is fed wherein...

  18. Oxidation behavior of a Ni-Fe support in SOFC anode atmosphere

    DEFF Research Database (Denmark)

    Xu, Na; Chen, Ming; Han, Minfang

    2018-01-01

    In this work, we investigated the long-term oxidation behavior of a Ni-Fe (1:1 weight ratio) support for solid oxide fuel cell (SOFC) applications. Ni-Fe supports were obtained through tape casting, high temperature sintering and pre-reducing in 97% H2/N2 (9/91)-3% H2O at 750 and 1000 °C, respect...... annealed in the two atmospheres maintained sufficiently high conductivity. The results from the current work demonstrate that the porous Ni-Fe support can be well employed in SOFCs, especially metal-supported SOFCs....

  19. Development of an autonomous transportable SOFC system operating on C-based fuel. The lilith system; Development of an autonomous transportable SOFC system operating on C-based fuel. The lilith system. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bucheli, O; Ihringer, R; Diethelm, S

    2006-07-01

    The aim of the project is to adapt a prototype portable SOFC system to the requirements of demonstrator for educational institutions as niche market. This involves on the one hand stable operation of the unit with reformed fuels, on the other hand the integration and control of auxiliaries such as fan and visualization. The result is aimed to be a practical communication vector, letting people touch SOFC technology. As intended, 2 redesigned systems have been realised and mounted. While design simplification allowed an easier construction of the units, more technical challenges than anticipated were encountered on the level of thermal management. The re-designed thermal system did not improve the thermal management to the level expected. Heat transfer to the stack chamber was on the lower limit, leading to rather high exhaust temperatures and also affected stack performance and robustness. Reforming of methanol worked to satisfaction on the short term, long-term data have not been obtained to date. Electronic controls, visualisation and auxiliaries have been elaborated based on the given specifications, but could not be validated on the complete system within the project time-frame. After a major personnel change within HTceramix, it is intended to pursue the activity next year with a new team. (author)

  20. Effect of additives in the baking of electrolytic materials for SOFC; SOFC yo denkaishitsu zairyo no shoseiji ni okeru tenkabutsu no koka

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, H. [Kansai Electric Power Co. Inc., Osaka (Japan)

    1998-09-10

    A technique is discovered for improving on the baking properties of cerium oxide which is one of the solid electrolytic materials for SOFC (solid oxide fuel cell). Cerium oxide, samarium oxide, and gallium oxide are weighed, each to the specified element ratio. The element ratio of cerium is fixed at 0.8 against the other elements except oxygen, and the element ratios of samarium or gallium are caused to change. Specimens containing gallium are designated as CSGa, those not containing as SDC. SDC baked at 1600degC and CSGa (1%) baked at 1450degC are similar to each other in terms of average grain diameter. Specimens with gallium added thereto can be baked at temperatures that are lower than these by approximately 150degC. The conductivity of CSGa (0.2%) baked at 1500degC is higher than that of SDC baked at the same temperature, and is similar to that of SDC baked at 1600degC. Baking is enhanced by the addition of 0.2% gallium. In the domain where more than 1% of gallium is in presence, conductivity lowers with an increase in the amount of gallium added. The conductivity of CSGa (1%) baked at 1450degC is similar to that of SDC baked at 1600degC. 4 figs., 1 tab.

  1. Planar Dirac diffusion

    International Nuclear Information System (INIS)

    Leo, Stefano de; Rotelli, Pietro

    2009-01-01

    We present the results of the planar diffusion of a Dirac particle by step and barrier potentials, when the incoming wave impinges at an arbitrary angle with the potential. Except for right-angle incidence this process is characterized by the appearance of spin flip terms. For the step potential, spin flip occurs for both transmitted and reflected waves. However, we find no spin flip in the transmitted barrier result. This is surprising because the barrier result may be derived directly from a two-step calculation. We demonstrate that the spin flip cancellation indeed occurs for each ''particle'' (wave packet) contribution. (orig.)

  2. Simplifying massive planar subdivisions

    DEFF Research Database (Denmark)

    Arge, Lars; Truelsen, Jakob; Yang, Jungwoo

    2014-01-01

    We present the first I/O- and practically-efficient algorithm for simplifying a planar subdivision, such that no point is moved more than a given distance εxy and such that neighbor relations between faces (homotopy) are preserved. Under some practically realistic assumptions, our algorithm uses ....... For example, for the contour map simplification problem it is significantly faster than the previous algorithm, while obtaining approximately the same simplification factor. Read More: http://epubs.siam.org/doi/abs/10.1137/1.9781611973198.3...

  3. Transport parameters of thin, supported cathode layers in solid oxide fuel cells (SOFCs); Transportparameter duenner, getraegerter Kathodenschichten der oxidkeramischen Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Wedershoven, Christian

    2010-12-22

    The aim of this work was to determine the transport properties of thin cathode layers, which are part of the composite layer of a fabricated anode-supported solid oxide fuel cell (SOFC). The transport properties of the anode and cathode have a significant influence on the electrochemical performance of a fuel cell stack and therefore represent an important parameter when designing fuel cell stacks. In order to determine the transport parameters of the cathode layers in a fabricated SOFC, it is necessary to permeate the thin cathode layer deposited on the gas-tight electrolyte with a defined gas transport. These thin cathode layers cannot be fabricated as mechanically stable single layers and cannot therefore be investigated in the diffusion and permeation experiments usually used to determine transport parameters. The setup of these experiments - particularly the sample holder - was therefore altered in this work. The result of this altered setup was a three-dimensional flow configuration. Compared to the conventional setup, it was no longer possible to describe the gas transport in the experiments with an analytical one-dimensional solution. A numerical solution process had to be used to evaluate the measurements. The new setup permitted a sufficiently symmetrical gas distribution and thus allowed the description of the transport to be reduced to a two-dimensional description, which significantly reduced the computational effort required to evaluate the measurements. For pressure-induced transport, a parametrized coherent expression of transport could be derived. This expression is equivalent to the analytical description of the transport in conventional measurement setups, with the exception of parameters that describe the geometry of the gas diffusion. In this case, a numerical process is not necessary for the evaluation. Using the transport parameters of mechanically stable anode substrates, which can be measured both in the old and the new setups, the old and

  4. Development of an integrated system for a SOFC for combined heat and power generation; Entwicklung eines integrierten Systems fuer eine SOFC mit Kraft-Waerme-Stoffkopplung

    Energy Technology Data Exchange (ETDEWEB)

    Stichtenoth, J.; Meyer-Pittroff, R.

    2002-06-01

    The feasibility of CO2 removal from the exhaust of a 250 kW{sub e} SOFC module, with recirculation of the liquefied CO2 is discussed for the example of a German brewery (Bayerische Staatsbrauerei Weihenstephan). An electric efficiency of 50% can be achieved provided that the liquefied CO2 is utilized to substitute CO2 liquefaction in another point of the process. The high-temperature waste heat of the 250 kW SOFC is fed into the brewer's copper via feedwater preheating. [German] In dieser Studie werden die Moeglichkeiten einer technischen Rueckgewinnung von CO{sub 2} aus dem Abgasstrom eines SOFC-Moduls mit 250 kW elektrischer Leistung und Rueckfuehrung des verfluessigten CO{sub 2} in den Wertschoepfungsprozess am Beispiel der Bayerischen Staatsbrauerei Weihenstephan untersucht. Unter der Voraussetzung, dass dieses verfluessigte CO{sub 2} als Produkt Verwendung findet und die CO{sub 2}-Verfluessigung an anderer Stelle substituiert, kann der von der SOFC gelieferte Energiebeitrag zur CO{sub 2}-Verfluessigung dem Gesamtsystem gutgeschrieben werden, so dass der elektrische Wirkungsgrad bei 50% bleibt. Die Hochtemperaturabwaerme der 250 kW-SOFC wird ueber eine Speisewasservorwaermung in den Dampfkessel der Brauerei eingekoppelt.

  5. Power generation characteristics of tubular type SOFC by wet process

    Energy Technology Data Exchange (ETDEWEB)

    Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

    1996-12-31

    The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

  6. Fabrication and characteristics of unit cell for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gwi-Yeol; Eom, Seung-Wook; Moon, Seong-In [Korea Electrotechnology Research Institute, Kyongnam (Korea, Republic of)] [and others

    1996-12-31

    Research and development on solid oxide fuel cells in Korea have been mainly focused on unit cell and small stack. Fuel cell system is called clean generation system which not cause NOx or SOx. It is generation efficiency come to 50-60% in contrast to 40% of combustion generation system. Among the fuel cell system, solid oxide fuel cell is constructed of ceramics, so stack construction is simple, power density is very high, and there are no corrosion problems. The object of this study is to develop various composing material for SOFC generation system, and to test unit cell performance manufactured. So we try to present a guidance for developing mass power generation system. We concentrated on development of manufacturing process for cathode, anode and electrolyte.

  7. Overview of SOFC/SOEC development at DTU Energy Conversion

    DEFF Research Database (Denmark)

    Hagen, Anke

    2014-01-01

    According to a broad political agreement in Denmark, the Danish energy system should become independent on fossil fuels like oil, coal and natural gas by the year 2050. This aim requires expansion of electricity production from renewable sources, in particular wind mills. In order to balance...... the fluctuating power production and to cope with the discrepancies between demand and supply of power, solid oxide fuel cells and electrolysis are considered key technologies. DTU Energy Conversion has a strong record in SOFC/SOEC research, with a close collaboration with industry, in particular with Danish...... Topsoe Fuel Cell A/S. Recent achievements will be presented ranging from development of new cell generations, manufacturability, up to testing under realistic operating conditions including degradation studies and high pressure testing. A strong focus will be on development of methodologies, e...

  8. Development of innovative metal-supported IT-SOFC technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The results of tests on a solid oxide fuel cell developed by Ceres Power Ltd are reported. The fabrication and construction of the thick film ceramic fuel cell on porous stainless steel substrate is described. Tests were conducted under constant load and under recycling. In stack development, the cells were interconnected by laser-welding the steel substrates to the plates. Possible concepts for an IT-SOFC based on a small CHP system were evaluated by computer modelling. The performance levels of the cell at various temperatures, and the cost estimates, are given as evidence of suitability for development towards commercialisation. The study was conducted as part of a UK DTI programme on New and Renewable Energy Sources.

  9. Relaxation of stresses during reduction of anode supported SOFCs

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Jørgensen, Peter Stanley

    2016-01-01

    To assess the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon......, accelerated creep, taking place during the reduction of a Ni-YSZ anode. This relaxes stresses at a much higher rate (~×104) than creep during operation. Thus, the phenomenon of accelerated creep during reduction has to be considered both in the production of stacks and in the analysis of the stress field...... of reduction should decrease significantly over minutes. In this work these internal stresses are measured in-situ before and after the reduction by use of X-ray diffraction. This is done by determining the elastic micro-strains (correlating to the stresses), which are assessed from the widening of the Bragg...

  10. Description of SOFC anode behavior by a mathematical modelling procedure

    International Nuclear Information System (INIS)

    Ielo, I.; Maggio, G.; Antonucci, V.; Giordano, N.

    1993-01-01

    One of the principal objectives in the development of SOFC is the identification of a stable Ni-cermet anode material with low polarization at high current density. In this respect, a mathematical approach, based on theoretical considerations, has been made in order to identify the optimal combination of geometrical and morphological characteristics of the system. The two limiting cases of diffusion-controlled and kinetic-controlled mechanisms are taken into account. Results in terms of limiting current have been treated by substituting into the related equations morphological parameters (surface area and pore size distribution of the support, metal content and surface area, electrode film thickness). Results are compared to existing experimental data and the influence of various parameters on the overall anode performance is evaluated. 2 tabs., 24 refs

  11. Dynamic Planar Convex Hull

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølfting; Jacob, Rico

    2002-01-01

    In this paper we determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage of the d......In this paper we determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage...... of the data structure is O(n). The data structure supports extreme point queries in a given direction, tangent queries through a given point, and queries for the neighboring points on the convex hull in O(log n) time. The extreme point queries can be used to decide whether or not a given line intersects...... the convex hull, and the tangent queries to determine whether a given point is inside the convex hull. We give a lower bound on the amortized asymptotic time complexity that matches the performance of this data structure....

  12. Spectroelectrochemical sensing: planar waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Susan E.; Shi Yining; Seliskar, Carl J.; Heineman, William R

    2003-09-30

    The spectroelectrochemical sensor combines in a single device electrochemistry, spectroscopy, and selective partitioning into a film, giving improved selectivity for applications that involve complex samples. Sensing is based on the change in optical signal that accompanies electrochemical modulation of analyte that has partitioned into the film. Two classes of optical quality chemically-selective films based on two different host materials, namely, sol-gel processed silica and cross-linked poly(vinyl alcohol) have been developed. Films are typically 400-700 nm thick. Three types of sensor platforms are discussed: a multiple internal reflection (MIR) optic consisting of a bilayer of an indium tin oxide (ITO) optically transparent electrode deposited on a 1-mm thick glass substrate, a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide (5-9 {mu}m thick) was over-coated with a thin film of ITO, and a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide channel was formed and a pair of electrodes deposited along side the channel. These sensors were evaluated with ferrocyanide and a selective film of PDMDAAC-SiO{sub 2}, where PDMDAAC=poly(dimethyl diallylammonium chloride)

  13. Spectroelectrochemical sensing: planar waveguides

    International Nuclear Information System (INIS)

    Ross, Susan E.; Shi Yining; Seliskar, Carl J.; Heineman, William R.

    2003-01-01

    The spectroelectrochemical sensor combines in a single device electrochemistry, spectroscopy, and selective partitioning into a film, giving improved selectivity for applications that involve complex samples. Sensing is based on the change in optical signal that accompanies electrochemical modulation of analyte that has partitioned into the film. Two classes of optical quality chemically-selective films based on two different host materials, namely, sol-gel processed silica and cross-linked poly(vinyl alcohol) have been developed. Films are typically 400-700 nm thick. Three types of sensor platforms are discussed: a multiple internal reflection (MIR) optic consisting of a bilayer of an indium tin oxide (ITO) optically transparent electrode deposited on a 1-mm thick glass substrate, a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide (5-9 μm thick) was over-coated with a thin film of ITO, and a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide channel was formed and a pair of electrodes deposited along side the channel. These sensors were evaluated with ferrocyanide and a selective film of PDMDAAC-SiO 2 , where PDMDAAC=poly(dimethyl diallylammonium chloride)

  14. Avances en el desarrollo de interconectores metálicos de celdas SOFC

    Directory of Open Access Journals (Sweden)

    Alvarado-Flores, J.

    2013-08-01

    Full Text Available Interest in solid oxide fuel cells (SOFC stems from their higher efficiencies and lower levels of emitted pollutants, compared to traditional power production methods. Interconnects are a critical part in SOFC stacks, which connect cells in series electrically, and also separate air or oxygen at the cathode side from fuel at the anode side. Therefore, the requirements of interconnects are the most demanding, i.e., to maintain high electrical conductivity, good stability in both reducing and oxidizing atmospheres, and close thermal expansion coefficient (TEC match and good compatibility with other SOFC ceramic components. This paper reviewed the interconnect materials, and coatings for metallic interconnect materials in a SOFC cell.El interés en las celdas de combustible de óxido sólido (SOFC, se deriva de su alta eficiencia y la capacidad de tener un bajo nivel de emisiones contaminantes, en comparación con los métodos tradicionales de producción de energía. Los interconectores, son parte crítica del ordenamiento de una celda SOFC, debido a que conecta en serie las celdas y además, separa el aire u oxígeno (cátodo del combustible (ánodo. Por lo tanto, los requisitos del interconector son muy exigentes, por ejemplo, es necesario mantener conductividad eléctrica elevada, óptima estabilidad tanto en atmósferas reductoras como oxidantes y el coeficiente de expansión térmica (TEC, debe ser compatible con los otros componentes cerámicos de la celda SOFC. Este artículo, revisa los materiales de interconexión, y materiales de revestimiento para interconectores metálicos en una celda SOFC.

  15. Thermodynamic modeling of the power plant based on the SOFC with internal steam reforming of methane

    International Nuclear Information System (INIS)

    Ivanov, Peter

    2007-01-01

    Mathematical model based on the thermodynamic modeling of gaseous mixtures is developed for SOFC with internal steam reforming of methane. Macroscopic porous-electrode theory, including non-linear kinetics and gas-phase diffusion, is used to calculate the reforming reaction and the concentration polarization. Provided the data concerning properties and costs of materials the model is fit for wide range of parametric analysis of thermodynamic cycles including SOFC

  16. Inkjet-based adaptive planarization (Conference Presentation)

    Science.gov (United States)

    Singhal, Shrawan; Grigas, Michelle M.; Khusnatdinov, Niyaz; Sreenivasan, Srinivasan V.

    2017-03-01

    that should have been polished away. Preventive techniques like dummy fill and patterned resist can be used to reduce the variation in pattern density. These techniques increase the complexity of the planarization process and significantly limit the device design flexibility. Contact Planarization (CP) has also been reported as an alternative to the CMP processing [7], [8]. A substrate is spin coated with a photo curable material and pre baked to remove residual solvent. An ultra-flat surface or an optical flat is pressed on the spin-coated wafer. The material is forced to reflow. Pressure is used to spread out material evenly and achieve global planarization. The substrate is then exposed to UV radiation to harden the photo curable material. Although attractive, this process is not adaptive as it does not account for differences in surface topography of the wafer and the optical flat, nor can it address all the parasitics that arise during the process itself. The optical flat leads to undesirable planarization of even the substrate nominal shape and nanotopography, which corrupts the final film thickness profile. Hence, it becomes extremely difficult to eliminate this signature to a desirable extent without introducing other parasitic signatures. An example of this is shown in Figure 1. In this paper, a novel adaptive planarization process has been presented that potentially addresses the problems associated with planarization of varying pattern density, even in the presence of pre-existing substrate topography [9]. This process is called Inkjet-enabled Adaptive Planarization (IAP). The IAP process uses an inverse optimization scheme, built around a validated fluid mechanics-based forward model [10], that takes the pre-existing substrate topography and pattern layout as inputs. It then generates an inkjet drop pattern with a material distribution that is correlated with the desired planarization film profile. This allows a contiguous film to be formed with the desired

  17. Development of solid oxide fuel cells (SOFC); Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.M.B. de; Carvalho, L.F.V. de; Alencar, M.G de; Boaventura, J.S. [Universidade Federal da Bahia (DFQ/UFBA), Salvador, BA (Brazil). Dept de Fisico-Quimica. Grupo de energia e Ciencias dos Materiais], e-mail: bventura@ufba.br

    2008-07-01

    The most promising technology for generating electric power, with reduced environmental impact, is the fuel cell. This technology is virtually non-polluting and the fuel supplies can be renewable. Therefore is necessary to study the technique of preparing the entire anode / electrolyte / cathode to optimize its operation. There are still major challenges to making the SOFC economically viable. The key is the improvement of manufacturing of its components and use of materials that can simultaneously reduce costs and reduce the temperature of operation. Among the properties of the cell, was shown the dependence of the efficiency of the device on the properties of the electrolyte, particularly its thickness. The mixture of YSZ with GDC in the composition of the anode and electrolyte aims to obtain a material with greater ionic conductivity. After sintering the cell was characterized by scanning electron microscopy (SEM). (author)

  18. Fabricación de soportes anódicos metálicos para SOFC por vía pulvimetalúrgica

    Directory of Open Access Journals (Sweden)

    Arahuetes, E.

    2008-10-01

    Full Text Available The commercialization of environmentally-friendly power production technologies as solid oxide fuel cells (SOFC implies the cost reduction of the materials initially used in their design. The employment of a porous metallic support that significantly reduces the amount of active ceramic material is an interesting option. In this work, the processing of four different alloys (two Fe-based and two Ni-based is evaluated for their possible use as porous metallic supports in SOFC. A binder system is proposed that, mixed with big-sized metallic powders, allows to obtain materials with the required porosity level (≥ 30%. Moreover, a stage of grinding prior to compaction of mixes binder-metallic powder allows the manufacturing of dimensionally stable components during binder removal, even although their high porosity.

    La comercialización de tecnologías de producción de energía medioambientalmente respetuosas, como las pilas de óxido sólido (SOFC, implica el abaratamiento de los materiales con que han sido, inicialmente, diseñadas. El empleo de un soporte metálico poroso que reduzca significativamente la cantidad de material cerámico activo es una opción muy interesante. En este trabajo se estudia el procesado de 4 aleaciones diferentes (dos base Fe y dos base Ni para su posible utilización como soportes metálicos porosos en SOFC. Se propone un sistema ligante que, mezclado con polvos metálicos de gran tamaño, permita obtener materiales con el nivel de porosidad requerida (≥ 30 %. Además, la realización de una etapa de granulado previa a la compactación de las mezclas de polvo metálico permite fabricar piezas que mantienen, pese a su elevada porosidad, la estabilidad dimensional durante el proceso de eliminación del ligante.

  19. On the nanostructuring and catalytic promotion of intermediate temperature solid oxide fuel cell (IT-SOFC) cathodes

    Science.gov (United States)

    Serra, José M.; Buchkremer, Hans-Peter

    Solid oxide fuel cells (SOFCs) are highly efficient energy converters for both stationary and mobile purposes. However, their market introduction still demands the reduction of manufacture costs and one possible way to reach this goal is the decrease of the operating temperatures, which entails the improvement of the cathode electrocatalytic properties. An ideal cathode material may have mixed ionic and electronic conductivity as well as proper catalytic properties. Nanostructuring and catalytic promotion of mixed conducting perovskites (e.g. La 0.58Sr 0.4Fe 0.8Co 0.2O 3- δ) seem to be promising approaches to overcoming cathode polarization problems and are briefly illustrated here. The preparation of nanostructured cathodes with relatively high surface area and enough thermal stability enables to improve the oxygen exchange rate and therefore the overall SOFC performance. A similar effect was obtained by catalytic promoting the perovskite surface, allowing decoupling the catalytic and ionic-transport properties in the cathode design. Noble metal incorporation may improve the reversibility of the reduction cycles involved in the oxygen reduction. Under the cathode oxidizing conditions, Pd seems to be partially dissolved in the perovskite structure and as a result very well dispersed.

  20. Numerical analysis on effect of aspect ratio of planar solid oxide fuel cell fueled with decomposed ammonia

    Science.gov (United States)

    Tan, Wee Choon; Iwai, Hiroshi; Kishimoto, Masashi; Brus, Grzegorz; Szmyd, Janusz S.; Yoshida, Hideo

    2018-04-01

    Planar solid oxide fuel cells (SOFCs) with decomposed ammonia are numerically studied to investigate the effect of the cell aspect ratio. The ammonia decomposer is assumed to be located next to the SOFCs, and the heat required for the endothermic decomposition reaction is supplied by the thermal radiation from the SOFCs. Cells with aspect ratios (ratios of the streamwise length to the spanwise width) between 0.130 and 7.68 are provided with the reactants at a constant mass flow rate. A parametric study is conducted by varying the cell temperature and fuel utility factor to investigate their effects on the cell performance in terms of the voltage efficiency. The effect of the heat supply to the ammonia decomposer is also studied. The developed model shows good agreement, in terms of the current-voltage curve, with the experimental data obtained from a short stack without parameter tuning. The simulation study reveals that the cell with the highest aspect ratio achieves the highest performance under furnace operation. On the other hand, the 0.750 aspect ratio cell with the highest voltage efficiency of 0.67 is capable of thermally sustaining the ammonia decomposers at a fuel utility of 0.80 using the thermal radiation from both sidewalls.

  1. Planar elliptic growth

    Energy Technology Data Exchange (ETDEWEB)

    Mineev, Mark [Los Alamos National Laboratory

    2008-01-01

    The planar elliptic extension of the Laplacian growth is, after a proper parametrization, given in a form of a solution to the equation for areapreserving diffeomorphisms. The infinite set of conservation laws associated with such elliptic growth is interpreted in terms of potential theory, and the relations between two major forms of the elliptic growth are analyzed. The constants of integration for closed form solutions are identified as the singularities of the Schwarz function, which are located both inside and outside the moving contour. Well-posedness of the recovery of the elliptic operator governing the process from the continuum of interfaces parametrized by time is addressed and two examples of exact solutions of elliptic growth are presented.

  2. Dynamic Planar Convex Hull

    DEFF Research Database (Denmark)

    Jacob, Riko

    We determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage of the data structure...... is O(n). The data structure supports extreme point queries in a given direction, tangent queries through a given point, and queries for the neighboring points on the convex hull in O(log n) time. The extreme point queries can be used to decide whether or not a given line intersects the convex hull......, and the tangent queries to determine whether a given point is inside the convex hull. The space usage of the data structure is O(n). We give a lower bound on the amortized asymptotic time complexity that matches the performance of this data structure....

  3. Improved Dynamic Planar Point Location

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Arge, Lars; Georgiadis, Loukas

    2006-01-01

    We develop the first linear-space data structures for dynamic planar point location in general subdivisions that achieve logarithmic query time and poly-logarithmic update time.......We develop the first linear-space data structures for dynamic planar point location in general subdivisions that achieve logarithmic query time and poly-logarithmic update time....

  4. Contracting a planar graph efficiently

    DEFF Research Database (Denmark)

    Holm, Jacob; Italiano, Giuseppe F.; Karczmarz, Adam

    2017-01-01

    the data structure, we can achieve optimal running times for decremental bridge detection, 2-edge connectivity, maximal 3-edge connected components, and the problem of finding a unique perfect matching for a static planar graph. Furthermore, we improve the running times of algorithms for several planar...

  5. Planar Poincare chart - A planar graphic representation of the state of light polarization

    Science.gov (United States)

    Tedjojuwono, Ken K.; Hunter, William W., Jr.; Ocheltree, Stewart L.

    1989-01-01

    The planar Poincare chart, which represents the complete planar equivalence of the Poincare sphere, is proposed. The four sets of basic lines are drawn on two separate charts for the generalization and convenience of reading the scale. The chart indicates the rotation of the principal axes of linear birefringent material. The relationships between parameters of the two charts are given as 2xi-2phi (orientation angle of the major axis-ellipticity angle) pair and 2alpha-delta (angle of amplitude ratio-phase difference angle) pair. The results are useful for designing and analyzing polarization properties of optical components with birefringent properties.

  6. Studies on Perovskite-Based Electrodes for Symmetrical SOFCs

    Directory of Open Access Journals (Sweden)

    Dos Santos García, A. J.

    2008-10-01

    Full Text Available The use of the same material as anode and cathode in symmetrical solid oxide fuel cells (SFCs promises notable benefits as easier fabrication, hence lower cost production and resistance to carbon formation upon fuel cracking. Although chromites and chromo-manganites have been proposed as candidate electrode materials for this novel SOFC configuration, demonstrating promising performances, further work is required to develop compositions exhibiting higher efficiencies. In the present work we evaluate the structural evolution from cubic to orthorhombic unit cells with increasing the Fe content and the performance of La4Sr8Ti12-xFexO38-δ (LSTF phases and compare their response with other symmetrical electrodes. The electrochemical performance is 20% higher when using graded LSTF electrodes than in other perovskite-based systems.

    La utilización simultánea de un mismo material cerámico como ánodo y cátodo en pilas de combustible de óxido sólido simétricas (SFCs aporta una serie de beneficios entre los que figura una fabricación más sencilla, reducción de los costes de producción, así como resistencia a la formación de depósitos de carbón por craqueo del combustible. Recientemente, cromitas y cromomanganitas han sido propuestos como materiales capaces de adoptar esta novedosa configuración SOFC y, si bien los resultados obtenidos son prometedores, se requiere de una mayor investigación para el desarrollo de nuevas composiciones que presenten eficiencias más elevadas. En el presente trabajo, se evalúan la evolución de la estructura desde celdas cúbicas a ortorrómbicas al aumentar el contenido en Fe y las prestaciones del sistema La4Sr8Ti12-xFexO38-δ (LSTF y se compara su respuesta con otros electrodos simétricos, observándose que el rendimiento es hasta un 20% mayor en el caso de emplear electrodos LSTF que en

  7. Mesoporous zirconia-ceria for anodes of SOFC and catalyzer

    Energy Technology Data Exchange (ETDEWEB)

    Fantini, Marcia Carvalho de Abreu; Cassimiro, Vinicius Roberto de Sylos; Monteiro, Rafael Cartoni, E-mail: mfantini@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica

    2016-07-01

    Full text: The ceria (CeO{sub 2}) and zirconia (ZrO{sub 2}) based materials are present in several technological applications, mainly as Solid Oxide Fuel Cells (SOFC) anodes and catalysts, for hydrogen production and automotive converter (Three-Way Catalysis). The solid solution Zr{sub x}Ce{sub 1-x}O{sub 2-δ} has attracted special attention, since it shows better thermal stability and higher oxygen storage capacity (OSC), if compared to the non-doped oxides. The mesoporous materials (pores of 2 to 50 nm) show high surface area and gas permeability, important properties for SOFCs and catalysts efficiency. In this work, mesoporous ceria-zirconia (Zr{sub 0.1}Ce{sub 0.9}O{sub 2-δ}) was synthesized by a sol-gel route using inorganic chlorides (ZrCl{sub 4} e CeCl{sub 3.7}H{sub 2}O) as precursors, block copolymer P123 (PEO{sub 20}PPO{sub 70}PEO{sub 20}) as template and TIPB (triisopropyl- benzene) as swelling agent. The solution was submitted to hydrothermal treatment for 48h at 80°C and calcined at 400°C to remove the template, resulting in the crystallized oxide. The characterization was performed by X-ray diffraction at high angles (XRD), small angle X-ray scattering (SAXS), nitrogen adsorption isotherms (NAI) and transmission and scanning electron microscopy (TEM and SEM). The results showed that the material has high surface area (≈ 110 m{sup 2}g{sup -1}), a wide pore size distribution with mean values around 30 nm, predominant cubic phase Fm3m and, in less quantity, tetragonal P4{sub 2}/nmc. The micrographs revealed that the oxide is totally nano-crystallized, having pores with slit shape and a secondary smaller mesoporosity with a narrow size distribution. The amount of P123 in the synthesis was also varied in order to produce pores with different shapes. Four samples were produced with different TIPB/P123 mass rate (0, 1, 2, 4), therefore was possible to verify the pore size expansion due to the swelling addition. The structural and morphological properties

  8. Measurement of residual stresses in deposited films of SOFC component materials

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T.; Momma, A.; Nagata, S.; Kasuga, Y. [Electrotechnical Lab., Ibaraki (Japan)

    1996-12-31

    The stress induced in Solid oxide fuel cells (SOFC)s has important influence on the lifetime of SOFC. But the data on stress in SOFC and mechanical properties of SOW component materials have not been accumulated enough to manufacture SOFC. Especially, the data of La{sub 1-x}Sr{sub x}MnO{sub 3} cathode and La{sub 1-x}Sr{sub x}CrO{sub 3} interconnection have been extremely limited. We have estimated numerically the dependences of residual stress in SOFC on the material properties, the cell structure and the fabrication temperatures of the components, but these unknown factors have caused obstruction to simulate the accurate behavior of residual stress. Therefore, the residual stresses in deposited La{sub 1-x}Sr{sub x}MnO{sub 3} and La{sub 1-x}Sr{sub x}CrO{sub 3} films are researched by the observation of the bending behavior of the substrate strips. The films of SOFC component materials were prepared by the RF sputtering method, because: (1) It can fabricate dense films of poor sinterable material such as La{sub 1-x}Sr{sub x}CrO{sub 3} compared with sintering or plasma spray method. (2) For the complicated material such as perovskite materials, the difference between the composition of a film and that of a target material is generally small. (3) It can fabricate a thick ceramics film by improving of the deposition rate. For example, Al{sub 2}O{sub 3} thick films of 50{mu}m can be fabricated with the deposition rate of approximately 5{mu}m/h industrially. In this paper, the dependence of residual stress on the deposition conditions is defined and mechanical properties of these materials are estimated from the results of the experiments.

  9. Contact planarization of ensemble nanowires

    Science.gov (United States)

    Chia, A. C. E.; LaPierre, R. R.

    2011-06-01

    The viability of four organic polymers (S1808, SC200, SU8 and Cyclotene) as filling materials to achieve planarization of ensemble nanowire arrays is reported. Analysis of the porosity, surface roughness and thermal stability of each filling material was performed. Sonication was used as an effective method to remove the tops of the nanowires (NWs) to achieve complete planarization. Ensemble nanowire devices were fully fabricated and I-V measurements confirmed that Cyclotene effectively planarizes the NWs while still serving the role as an insulating layer between the top and bottom contacts. These processes and analysis can be easily implemented into future characterization and fabrication of ensemble NWs for optoelectronic device applications.

  10. Computational Study on a PTAS for Planar Dominating Set Problem

    Directory of Open Access Journals (Sweden)

    Qian-Ping Gu

    2013-01-01

    Full Text Available The dominating set problem is a core NP-hard problem in combinatorial optimization and graph theory, and has many important applications. Baker [JACM 41,1994] introduces a k-outer planar graph decomposition-based framework for designing polynomial time approximation scheme (PTAS for a class of NP-hard problems in planar graphs. It is mentioned that the framework can be applied to obtain an O(2ckn time, c is a constant, (1+1/k-approximation algorithm for the planar dominating set problem. We show that the approximation ratio achieved by the mentioned application of the framework is not bounded by any constant for the planar dominating set problem. We modify the application of the framework to give a PTAS for the planar dominating set problem. With k-outer planar graph decompositions, the modified PTAS has an approximation ratio (1 + 2/k. Using 2k-outer planar graph decompositions, the modified PTAS achieves the approximation ratio (1+1/k in O(22ckn time. We report a computational study on the modified PTAS. Our results show that the modified PTAS is practical.

  11. Capability of a SOFC-APU to optimise the fuel consumption of motor vehicles; Potenzial einer SOFC-APU bei der Verbrauchsoptimierung von Kraftfahrzeugen

    Energy Technology Data Exchange (ETDEWEB)

    Diegelmann, Christian B.

    2008-04-28

    While the energy system motor vehicle is analysed in this work different application possibilities of a SOFC-Auxiliary Power Unit for reducing the fuel consumption are identified. Apart from the pure electric power supply the APU can support functions like the engine-stop automatism or electric driving (hybrid vehicle). In addition the SOFC-APU generates waste heat at a high temperature level. The waste heat can be used for heating the passenger cabin or for preheating the combustion engine. Several methods are used for evaluating the conservation potentials. A simple estimate of the fuel consumption by means of medium efficiency and power already suffices to identify and evaluate the major impacts. The conservation potential of a SOFC-APU mainly depends on three factors, the start-up consumption of the APU, the operating period and the required electric power. A cold APU must first be heated-up to an operational temperature between 700 and 800 degrees Celsius. The heat-up process requires energy resulting in an excess consumption first. This excess consumption will only be compensated by the high efficiency of the SOFC-APU after a longer operating period. The operating period strongly depends on the electric power. In case of higher electric power the APU achieves a higher conservation rate. An APU is particularly interesting in standard applications with high energy demand. The APU avoids an operation of the combustion engine in the extreme underload range. In case of an air-conditioning at idling speed lasting for 30 minutes a fuel conservation of approx. 36% can be achieved including the start-up consumption. Conservation potentials in fuel consumption can only be achieved in the driving mode if the APU is operational and in case of a longer operating period. The difference in consumption compared to vehicles without APU was determined at vehicles with different basic operating strategies (current vehicle, vehicle with engine-stop automatism, vehicle with

  12. Discrete modelling of the electrochemical performance of SOFC electrodes

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Martin, C.L.; Bultel, Y.; Bouvard, D.; Siebert, E.

    2006-01-01

    The composite anode and cathode of solid oxide fuel cells (SOFC) are modelled as sintered mixtures of electrolyte and electrocatalyst particles. A particle packing is first created numerically by the discrete element method (DEM) from a loose packing of 40 000 spherical, monosized, homogeneously mixed, and randomly positioned particles. Once the microstructure is sintered numerically, the effective electrode conductivity is determined by discretization of the particle packing into a resistance network. Each particle contact is characteristic of a bond resistance that depends on contact geometry and particle properties. The network, which typically consists of 120 000 bond resistances in total, is solved using Kirchhoff's current law. Distributions of local current densities and particle potentials are then performed. We investigate how electrode performance depends on parameters such as electrode composition, thickness, density and intrinsic material conductivities that are temperature dependent. The simulations show that the best electrode performance is obtained for compositions close to the percolation threshold of the electronic conductor. Depending on particle conductivities, the electrode performance is a function of its thickness. Additionally, DEM simulations generate useful microstructural information such as: coordination numbers, triple phase boundary length and percolation thresholds

  13. High Performance Fe-Co Based SOFC Cathodes

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent; Hansen, Karin Vels; Mogensen, Mogens Bjerg

    2010-01-01

    With the aim of reducing the temperature of the solid oxide fuel cell (SOFC), a new high-performance perovskite cathode has been developed. An area-specific resistance (ASR) as low as 0.12 Ωcm2 at 600 °C was measured by electrochemical impedance spectroscopy (EIS) on symmetrical cells. The cathode...... is a composite between (Gd0.6Sr0.4)0.99Fe0.8Co0.2O3-δ (GSFC) and Ce0.9Gd0.1O1.95 (CGO10). Examination of the microstructure of the cathodes by scanning electron microscopy (SEM) revealed a possibility of further optimisation of the microstructure in order to increase the performance of the cathodes. It also...... seems that an adjustment of the sintering temperature will make a lowering of the ASR value possible. The cathodes were compatible with ceria-based electrolytes but reacted to some extent with zirconia-based electrolytes depending on the sintering temperature....

  14. Lanthanum germanate-based apatites as electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D.; Diaz-Carrasco, P.; Ramos-Barrado, J.R. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain)

    2011-02-15

    Germanate apatites with composition La{sub 10-x}Ge{sub 5.5}Al{sub 0.5}O{sub 26.75-3x/2} have been evaluated for the first time as possible electrolytes for solid oxide fuel cells (SOFCs). Different electrode materials have been considered in this study, i.e. manganite, ferrite, nickelates and cobaltite as cathode materials; and NiO-CGO composite and chromium-manganite as anodes. The chemical compatibility and electrochemical performance of these electrodes with La{sub 9.8}Ge{sub 5.5}Al{sub 0.5}O{sub 26.45} have been studied by X-ray powder diffraction (XRPD) and impedance spectroscopy. The XRPD analysis did not reveal appreciable bulk reactivity with the formation of reaction products between the germanate electrolyte and these electrodes up to 1,200 C. However, a significant cation interdiffusion was observed by energy dispersive spectroscopy (EDS) at the electrode/electrolyte interface, which leads to a significant decrease of the performance of these electrodes. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Parametric study of anodic microstructures to cell performance of planar solid oxide fuel cell using measured porous transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.M.; Shy, S.S.; Chien, C.W. [Department of Mechanical Engineering, National Central University, 300 Jhong-da Road, Jhong-li 32001 (China); Lee, C.H. [Institute of Nuclear Energy Research, Lung-tan, Tao-yuan 32546 (China)

    2010-04-15

    This study reports effects of porosity ({epsilon}), permeability (k) and tortuosity ({tau}) of anodic microstructures to peak power density (PPD) of a single-unit planar anode-supported SOFC based on 3D electrochemical flow models using measured porous transport properties. Applying particle image velocimetry, a transparent porous rib-channel with different {epsilon} is applied to measure an effective viscosity ({mu}{sub e}) in the Brinkman equation commonly used to predict flow properties in porous electrodes. It is found that, contrary to the popular scenario, {mu}{sub e} is not equal to the fluid viscosity ({mu}{sub f}), but it is several orders in magnitude smaller than {mu}{sub f} resulting in more than 10% difference on values of PPD. Numerical analyses show: (1) while keeping k and {tau} fixed with {epsilon} varying from 0.2 to 0.6, the highest PPD occurs at {epsilon} = 0.3 where the corresponding triple-phase-boundary length is a maximum; (2) PPD increases slightly with k when k{<=}10{sup -11} m{sup 2} due to the diffusion limitation in anode; and (3) PPD decreases with {tau} when {tau}>1.5 due to the accumulation of non-depleted products. Hence, a combination of {epsilon}=0.3, k=10{sup -11}m{sup 2}, and {tau}=1.5 is suggested for achieving higher cell performance of planar SOFC. (author)

  16. Planar graphs theory and algorithms

    CERN Document Server

    Nishizeki, T

    1988-01-01

    Collected in this volume are most of the important theorems and algorithms currently known for planar graphs, together with constructive proofs for the theorems. Many of the algorithms are written in Pidgin PASCAL, and are the best-known ones; the complexities are linear or 0(nlogn). The first two chapters provide the foundations of graph theoretic notions and algorithmic techniques. The remaining chapters discuss the topics of planarity testing, embedding, drawing, vertex- or edge-coloring, maximum independence set, subgraph listing, planar separator theorem, Hamiltonian cycles, and single- or multicommodity flows. Suitable for a course on algorithms, graph theory, or planar graphs, the volume will also be useful for computer scientists and graph theorists at the research level. An extensive reference section is included.

  17. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  18. Modeling and Analysis of Transport Processes and Efficiency of Combined SOFC and PEMFC Systems

    Directory of Open Access Journals (Sweden)

    Abid Rabbani

    2014-08-01

    Full Text Available A hybrid fuel cell system (~10 kWe for an average family house including heating is proposed. The investigated system comprises a Solid Oxide Fuel Cell (SOFC on top of a Polymer Electrolyte Fuel Cell (PEFC. Hydrogen produced from the off-gases of the SOFC can be fed directly to the PEFC. Simulations for the proposed system were conducted using different fuels. Here, results for natural gas (NG, dimethyl ether (DME and ethanol as a fuel are presented and analysed. Behaviour of the proposed system is further investigated by comparing the effects of key factors such as utilisation factor, operating conditions, oxygen-to-carbon (O/C ratios and fuel preheating effects on these fuels. The combined system improves the overall electrical conversion efficiency compared with standalone PEFC or SOFC systems. For the combined SOFC and PEFC system, the overall power production was increased by 8%–16% and the system efficiency with one of the fuels is found to be 12% higher than that of the standalone SOFC system.

  19. Electro-catalysts for hydrogen production from ethanol for use in SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcos Aurelio da; Paz Fiuza, Raigenis da; Guedes, Bruna C.; Pontes, Luiz A.; Boaventura, Jaime Soares [UFBA, Salvador, Bahia (Brazil). Energy and Materials Science Group

    2010-07-01

    Nickel and cobalt catalysts, supported on YSZ, were prepared by wet impregnation, with and without citric acid; the metal load was 10 and 35% by weight. The catalyst composition was studied by XRF, XPS and SEM-EDS. At low metal concentration, the results of these techniques presented comparables figures; at high concentration, SEM-EDS suggested a non-uniform distribution. The analysis showed that the solids were mixed oxides and formed an alloy after reduction. The surface passivation was possible under controlled conditions. The catalytic test with the steam reforming of ethanol indicated that the metal load had almost no effect on the catalytic activity, but decreased its selectivity. Afterwards, a unitary SOFC was prepared with deposition of the cathode layer. AFM and EIS were used for the characterization of SOFC components. They showed that the electro-catalyst surface was almost all covered with the metal phase, including the large pore walls of the anode. The YSZ phase dominates the material conductance of the complete SOFC assembly (anode/electrolyte/cathode). The unitary SOFC was tested with hydrogen, gaseous ethanol or natural gas; the SOFC operating with ethanol and hydrogen fuel presented virtually no over-potential. (orig.)

  20. Development of solid oxide fuel cells; Desenvolvimento de celulas a combustivel do tipo oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Boaventura, Jaime S.; Alencar, Marcelo Goncalves F. de; Amaral, Alexandre Alves do; Benedicto, Joao Paulo Santos; Silva, Marcos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Dept. de Fisico-Quimica

    2006-07-01

    Fuel cells allow the energy production without the thermodynamic restriction of the conversion of heat into work. Among their various types, the solid oxide fuel cells (SOFC), operating at high temperatures, allow the methane conversion into electricity directly on the anode. The main element of the SOFC is the structure A/E/C: anode/electrolyte/cathode, all sintered at high temperature as resistant ceramic materials. Dense electrolyte (YSZ: zirconia stabilized for Yttria) separates the anode (Ni+Co/YSZ: cobalt promoted nickel, supported on YSZ) and cathode (LSM: strontium-doped lanthanum manganite), both with porosity obtained by graphite addition. To obtain suitable A/E/C pellets, the layer sintering with appropriate mechanical and textural characteristics is essential, requiring excellent electric junctions between them. The cell performance has been evaluated between 850 and 950 degree C, using hydrogen or methane fuel; the tension and current for different resistance values in the electrical circuit have been measured. The cobalt addition to the cell anode significantly increased its activity for the reform reaction. The beneficial effect was probably due to the easier nickel reduction in cobalt presence. This work had the objectives of developing and evaluating electro-catalysts, as well as the solid oxide fuel cells using these catalysts as anode. Five SOFC models (SOFC 1 to SOFC 5) are described; all of them were developed aiming at improving the preparation of the anode/electrolyte/cathode structure (A/E/C). (author)

  1. Flat panel planar optic display

    Energy Technology Data Exchange (ETDEWEB)

    Veligdan, J.T. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

    1994-11-01

    A prototype 10 inch flat panel Planar Optic Display, (POD), screen has been constructed and tested. This display screen is comprised of hundreds of planar optic class sheets bonded together with a cladding layer between each sheet where each glass sheet represents a vertical line of resolution. The display is 9 inches wide by 5 inches high and approximately 1 inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

  2. CFD Model Of A Planar Solid Oxide Electrolysis Cell For Hydrogen Production From Nuclear Energy

    International Nuclear Information System (INIS)

    Grant L. Hawkes; James E. O'Brien; Carl M. Stoots; J. Stephen Herring

    2005-01-01

    A three-dimensional computational fluid dynamics (CFD) model has been created to model high temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell as it would exist in an electrolysis stack. Details of the model geometry are specific to a stack that was fabricated by Ceramatec2, Inc. and tested at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT2. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with experimental results obtained from an actual ten-cell stack tested at INL

  3. In vitro quantification of the performance of model-based mono-planar and bi-planar fluoroscopy for 3D joint kinematics estimation.

    Science.gov (United States)

    Tersi, Luca; Barré, Arnaud; Fantozzi, Silvia; Stagni, Rita

    2013-03-01

    Model-based mono-planar and bi-planar 3D fluoroscopy methods can quantify intact joints kinematics with performance/cost trade-off. The aim of this study was to compare the performances of mono- and bi-planar setups to a marker-based gold-standard, during dynamic phantom knee acquisitions. Absolute pose errors for in-plane parameters were lower than 0.6 mm or 0.6° for both mono- and bi-planar setups. Mono-planar setups resulted critical in quantifying the out-of-plane translation (error bi-planar in quantifying the rotation along bone longitudinal axis (error bi-planar (error comparable to bi-planar, but with halved computational costs, halved segmentation time and halved ionizing radiation dose. Bi-planar analysis better compensated for the out-of-plane uncertainty that is differently propagated to relative kinematics depending on the setup. To take its full benefits, the motion task to be investigated should be designed to maintain the joint inside the visible volume introducing constraints with respect to mono-planar analysis.

  4. Broadband Planar 5:1 Impedence Transformer

    Science.gov (United States)

    Ehsan, Negar; Hsieh, Wen-Ting; Moseley, Samuel H.; Wollack, Edward J.

    2015-01-01

    This paper presents a broadband Guanella-type planar impedance transformer that transforms so 50 omega to 10 omega with a 10 dB bandwidth of 1-14GHz. The transformer is designed on a flexible 50 micrometer thick polyimide substrate in microstrip and parallel-plate transmission line topologies, and is Inspired by the traditional 4:1 Guanella transformer. Back-to-back transformers were designed and fabricated for characterization in a 50 omega system. Simulated and measured results are in excellent agreement.

  5. Plastic Models Designed to Produce Large Height-to-Length Ratio Steady-State Planar and Axisymmetric (Radial) Viscous Liquid Laminar Flow Gravity Currents

    Science.gov (United States)

    Blanck, Harvey F.

    2012-01-01

    Naturally occurring gravity currents include events such as air flowing through an open front door, a volcanic eruption's pyroclastic flow down a mountainside, and the spread of the Bhopal disaster's methyl isocyanate gas. Gravity currents typically have a small height-to-distance ratio. Plastic models were designed and constructed with a…

  6. Infiltration of SOFC Stacks: Evaluation of the Electrochemical Performance Enhancement and the Underlying Changes in the Microstructure

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Zielke, Philipp; Høgh, Jens Valdemar Thorvald

    2016-01-01

    Experimental SOFC stacks with 10 SOFCs (LSM-YSZ/YSZ/Ni-YSZ) were infiltrated with CGO and Ni-CGO on the air and fuel side, respectively in an attempt to counter degradation and improve the output. The electrochemical performance of each cell was characterized (i) before infiltration, (ii) after i...

  7. SOFC LSM:YSZ cathode degradation induced by moisture: An impedance spectroscopy study

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Mogensen, Mogens Bjerg

    2011-01-01

    The cause of the degradation effect of moisture during operation of LSM cathode based SOFCs has been investigated by means of a detailed impedance characterization on LSM:YSZ composite cathode based SOFCs. Further the role of YSZ as cathode composite material was studied by measurements on SOFCs...... with a LSM:CGO composite cathode on a CGO interdiffusion barrier layer. It was found that both types of cathodes showed similar electrochemical characteristics towards the presence of moisture during operation. Upon addition and removal of moisture in the fed air the impedance study showed a change...... in the high frequency cathode arc, which is associated with the charge transport/transfer at the LSM/YSZ interface. On prolonged operation with the presence of moisture an ongoing increase in the high frequency cathode arc resulted in a permanent loss of cathode/electrolyte contact and thus increase...

  8. Robust automatic high resolution segmentation of SOFC anode porosity in 3D

    DEFF Research Database (Denmark)

    Jørgensen, Peter Stanley; Bowen, Jacob R.

    2008-01-01

    Routine use of 3D characterization of SOFCs by focused ion beam (FIB) serial sectioning is generally restricted by the time consuming task of manually delineating structures within each image slice. We apply advanced image analysis algorithms to automatically segment the porosity phase of an SOFC...... anode in 3D. The technique is based on numerical approximations to partial differential equations to evolve a 3D surface to the desired phase boundary. Vector fields derived from the experimentally acquired data are used as the driving force. The automatic segmentation compared to manual delineation...... reveals and good correspondence and the two approaches are quantitatively compared. It is concluded that the. automatic approach is more robust, more reproduceable and orders of magnitude quicker than manual segmentation of SOFC anode porosity for subsequent quantitative 3D analysis. Lastly...

  9. Miniaturized Air-Driven Planar Magnetic Generators

    Directory of Open Access Journals (Sweden)

    Jingjing Zhao

    2015-10-01

    Full Text Available This paper presents the design, analysis, fabrication and testing of two miniaturized air-driven planar magnetic generators. In order to reduce the magnetic resistance torque, Generator 1 establishes a static magnetic field by consisting a multilayer planar coil as the stator and two multi-pole permanent-magnet (PM rotors on both sides of the coil. To further decrease the starting torque and save more space, Generator 2 adopts the multilayer planar coil as the rotor and the multi-pole PMs as the stator, eliminating the casing without compromising the magnetic structure or output performance. The prototypes were tested gathering energy from wind which can work at a low wind speed of 1~2 m/s. Prototype of Generator 1 is with a volume of 2.61 cm3 and its normalized voltage reaches 485 mV/krpm. Prototype of Generator 2 has a volume of 0.92 cm3 and a normalized voltage as high as 538 mV/krpm. Additionally, output voltage can be estimated at better than 96% accuracy by the theoretical model developed in this paper. The two micro generators are capable of producing substantial electricity with little volume to serve as compact power conversion devices.

  10. Oxygen reduction kinetics on mixed conducting SOFC model cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, F.S.

    2006-07-01

    The kinetics of the oxygen reduction reaction at the surface of mixed conducting solid oxide fuel cell (SOFC) cathodes is one of the main limiting factors to the performance of these promising systems. For ''realistic'' porous electrodes, however, it is usually very difficult to separate the influence of different resistive processes. Therefore, a suitable, geometrically well-defined model system was used in this work to enable an unambiguous distinction of individual electrochemical processes by means of impedance spectroscopy. The electrochemical measurements were performed on dense thin film microelectrodes, prepared by PLD and photolithography, of mixed conducting perovskite-type materials. The first part of the thesis consists of an extensive impedance spectroscopic investigation of La0.6Sr0.4Co0.8Fe0.2O3 (LSCF) microelectrodes. An equivalent circuit was identified that describes the electrochemical properties of the model electrodes appropriately and enables an unambiguous interpretation of the measured impedance spectra. Hence, the dependencies of individual electrochemical processes such as the surface exchange reaction on a wide range of experimental parameters including temperature, dc bias and oxygen partial pressure could be studied. As a result, a comprehensive set of experimental data has been obtained, which was previously not available for a mixed conducting model system. In the course of the experiments on the dc bias dependence of the electrochemical processes a new and surprising effect was discovered: It could be shown that a short but strong dc polarisation of a LSCF microelectrode at high temperature improves its electrochemical performance with respect to the oxygen reduction reaction drastically. The electrochemical resistance associated with the oxygen surface exchange reaction, initially the dominant contribution to the total electrode resistance, can be reduced by two orders of magnitude. This &apos

  11. Thermodynamic Model of a Very High Efficiency Power Plant based on a Biomass Gasifier, SOFCs, and a Gas Turbine

    Directory of Open Access Journals (Sweden)

    P V Aravind

    2012-07-01

    Full Text Available Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable.

  12. Advanced Measurement and Modeling Techniques for Improved SOFC Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Adler; L. Dunyushkina; S. Huff; Y. Lu; J. Wilson

    2006-12-31

    The goal of this project was to develop an improved understanding of factors governing performance and degradation of mixed-conducting SOFC cathodes. Two new diagnostic tools were developed to help achieve this goal: (1) microelectrode half-cells for improved isolation of cathode impedance on thin electrolytes, and (2) nonlinear electrochemical impedance spectroscopy (NLEIS), a variant of traditional impedance that allows workers to probe nonlinear rates as a function of frequency. After reporting on the development and efficacy of these tools, this document reports on the use of these and other tools to better understand performance and degradation of cathodes based on the mixed conductor La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (LSC) on gadolinia or samaria-doped ceria (GDC or SDC). We describe the use of NLEIS to measure O{sub 2} exchange on thin-film LSC electrodes, and show that O{sub 2} exchange is most likely governed by dissociative adsorption. We also describe parametric studies of porous LSC electrodes using impedance and NLEIS. Our results suggest that O{sub 2} exchange and ion transport co-limit performance under most relevant conditions, but it is O{sub 2} exchange that is most sensitive to processing, and subject to the greatest degradation and sample-to-sample variation. We recommend further work that focuses on electrodes of well-defined or characterized geometry, and probes the details of surface structure, composition, and impurities. Parallel work on primarily electronic conductors (LSM) would also be of benefit to developers, and to improved understanding of surface vs. bulk diffusion.

  13. Thermodynamic and Thermoeconomic investigation of an Integrated Gasification SOFC and Stirling Engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    Thermodynamic and thermoeconomic investigation of a small scale Integrated Gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kW have been performed. Woodchips are used as gasification feedstock to produce syngas which......-product and the cost of hot water was found to be 0.0214$/kWh. When compared to other renewable systems at similar scale, it shows that if both SOFC and Stirling engine technology emerges enter commercialization phase, then they can deliver electricity at a cost rate which is competitive with corresponding renewable...

  14. Quality Assurance of Solid Oxide Fuel Cell (SOFC) and Electrolyser (SOEC) Stacks

    DEFF Research Database (Denmark)

    Lang, Michael; Auer, Corinna; Couturier, Karine

    2017-01-01

    In the EU-funded project “Solid oxide cell and stack testing and quality assurance” (SOCTESQA) standardized and industry wide test modules and programs for high temperature solid oxide cells and stacks are being developed. These test procedures can be applied for the fuel cell (SOFC......), the electrolysis (SOEC) and in the combined SOFC/SOEC mode. In order to optimize the test modules the project partners have tested identical SOC stacks with the same test programs in several testing campaigns. Altogether 10 pre-normative test modules were developed: Start-up, current-voltage characteristics...

  15. Binary co-generative plants with height temperature SOFC fuel cells

    International Nuclear Information System (INIS)

    Tashevski, D; Dimitrov, K.; Armenski, S.

    2005-01-01

    In this paper, a field of binary co-generative plants with height temperature SOFC fuel cells is presented. Special attention of application of height temperature SOFC fuel cells and binary co-generative units has been given. These units made triple electricity and heat. Principle of combination of fuel cells with binary cycles has been presented. A model and computer programme for calculation of BKPFC, has been created. By using the program, all the important characteristic-results are calculated: power, efficiency, emission, dimension and economic analysis. On base of results, conclusions and recommendations has been given. (Author)

  16. Binary co-generative plants with height temperature SOFC fuel cells

    International Nuclear Information System (INIS)

    Tashevski, D; Dimitrov, K.; Armenski, S.

    2006-01-01

    In this paper, a field of binary co-generative plants with height temperature SOFC fuel cells is presented. Special attention of application of height temperature SOFC fuel cells and binary co-generative units has been given. These units made triple electricity and heat. Principle of combination of fuel cells with binary cycles has been presented. A model and computer programme for calculation of BKPFC, has been created. By using the program, all the important characteristic-results are calculated: power, efficiency, emission, dimension and economic analysis. On base of results, conclusions and recommendations has been given. (Author)

  17. The value of filtered planar images in pediatric DMSA scans

    International Nuclear Information System (INIS)

    Mohammed, A.M.; Naddaf, S.Y.; Elgazzar, A.H.; Al-Abdul Salam, A.A.; Omar, A.A.

    2006-01-01

    The study was designed to demonstrate the value of filtered planar images in paediatric DMSA scanning. One hundred and seventy three patients ranged in age from 15 days to 12 years (mean: 4.3 years) with urinary tract infection (UTI) and clinical and/or laboratory suspicion of acute pyelonephritis (APN) were retrospectively studied. Planar images were filtered using Butterworth filter. The scan findings were reported as positive, negative or equivocal for cortical defects. Each scan was read in a double-blind fashion by two nuclear medicine physicians to evaluate inter-observer variations. Each kidney was divided into three zones, upper, middle and lower, and each zone was graded as positive, negative or equivocal for the presence of renal defects. Renal cortical defects were found in 66 patients (91 kidneys and 186 zones) with filtered images, 58 patients (81 kidneys and 175 zones) with planar images, and 69 patients (87 kidneys and 180 zones) with SPECT images. McNemar's test revealed statistically significant difference between filtered and planar images (p=0.038 for patients, 0.021 for kidneys and 0.034 for number of zones). Inter-observer agreement was 0.877 for filtered images, 0.915 for planar images and 0.915 for SPECT images. It was concluded that filtered planar images of renal cortex are comparable to SPECT images and can be used effectively in place of SPECT, when required, to shorten imaging time and eliminate motion artifacts, especially in the paediatric population. (author)

  18. Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

    Science.gov (United States)

    Chow, Justin Jeff

    Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

  19. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    Science.gov (United States)

    Martinez, Andrew S.; Brouwer, Jacob; Samuelsen, G. Scott

    2012-09-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonable dynamic response. The use of diesel fuel reformate in the SOFC presents a challenge to the electrochemistry, especially as it relates to control and optimization of the fuel utilization in the anode compartment. This is found to arise from the large amount of carbon monoxide in diesel reformate that is fed to the fuel cell, limiting the maximum fuel utilization possible. This presents an opportunity for further investigations into carbon monoxide electrochemical oxidation and/or system integration studies where the efficiency of the fuel reformer can be balanced against the needs of the SOFC.

  20. Planar permanent magnet multipoles: Measurements and configurations

    International Nuclear Information System (INIS)

    Cremer, T.; Tatchyn, R.

    1995-05-01

    Biplanar arrays of N rectangular permanent magnet (PM) blocks can be used to generate high quality N-pole fields in close proximity to the array axis. In applications featuring small-diameter charged particle beams, N-poles of adequate quality can be realized at relatively low cost using small volumes of PM material. In this paper we report on recent measurements performed on planar PM multipoles, and discuss techniques for improving the field quality of such devices at distances appreciably far away from the axis. Applications to hybrid/PM insertion device designs for linac-driven Free Electron Laser (FEL) operation in the x-ray range are described

  1. Experimental study on the 300W class planar type solid oxide fuel cell stack: Investigation for appropriate fuel provision control and the transient capability of the cell performance

    International Nuclear Information System (INIS)

    Komatsu, Y; Brus, G; Szmyd, J S; Kimijima, S

    2012-01-01

    The present paper reports the experimental study on the dynamic behavior of a solid oxide fuel cell (SOFC). The cell stack consists of planar type cells with standard power output 300W. A Major subject of the present study is characterization of the transient response to the electric current change, assuming load-following operation. The present studies particularly focus on fuel provision control to the load change. Optimized fuel provision improves power generation efficiency. However, the capability of SOFC must be restricted by a few operative parameters. Fuel utilization factor, which is defined as the ratio of the consumed fuel to the supplied fuel is adopted for a reference in the control scheme. The fuel flow rate was regulated to keep the fuel utilization at 50%, 60% and 70% during the current ramping. Lower voltage was observed with the higher fuel utilization, but achieved efficiency was higher. The appropriate mass flow control is required not to violate the voltage transient behavior. Appropriate fuel flow manipulation can contribute to moderate the overshoot on the voltage that may appear to the current change. The overshoot on the voltage response resulted from the gradual temperature behavior in the SOFC stack module.

  2. Experimental study on the 300W class planar type solid oxide fuel cell stack: Investigation for appropriate fuel provision control and the transient capability of the cell performance

    Science.gov (United States)

    Komatsu, Y.; Brus, G.; Kimijima, S.; Szmyd, J. S.

    2012-11-01

    The present paper reports the experimental study on the dynamic behavior of a solid oxide fuel cell (SOFC). The cell stack consists of planar type cells with standard power output 300W. A Major subject of the present study is characterization of the transient response to the electric current change, assuming load-following operation. The present studies particularly focus on fuel provision control to the load change. Optimized fuel provision improves power generation efficiency. However, the capability of SOFC must be restricted by a few operative parameters. Fuel utilization factor, which is defined as the ratio of the consumed fuel to the supplied fuel is adopted for a reference in the control scheme. The fuel flow rate was regulated to keep the fuel utilization at 50%, 60% and 70% during the current ramping. Lower voltage was observed with the higher fuel utilization, but achieved efficiency was higher. The appropriate mass flow control is required not to violate the voltage transient behavior. Appropriate fuel flow manipulation can contribute to moderate the overshoot on the voltage that may appear to the current change. The overshoot on the voltage response resulted from the gradual temperature behavior in the SOFC stack module.

  3. Combining science and practice in the Danish DK-SOFC program

    DEFF Research Database (Denmark)

    Knudsen, P.; Bagger, C.; Mogensen, Mogens Bjerg

    1994-01-01

    A three-year solid oxide fuel cells (SOFC) development program completed in 1992 has produced 10 cm2 cells with area-specific resistances in the range 0.25 to 0.40 OMEGA cm2 at 1000-degrees-C. Cathode and interconnect materials were produced in the program. Sintering of electrodes, electrolyte...

  4. Progress of SOFC/SOEC Development at DTU Energy: From Materials to Systems

    DEFF Research Database (Denmark)

    Hagen, Anke; Hendriksen, Peter Vang

    2017-01-01

    DTU Energy has over the past 20 years had a very substantial effort on SOFC/SOEC development. The current project volume corresponds to ~40 man years per year. Activities span over a broad range in the value chain, from materials to cells, stacks and analyses at energy system level. In addition...

  5. SOFC anode. Hydrogen oxidation at porous nickel and nickel/zirconia electrodes

    NARCIS (Netherlands)

    de Boer, B.

    1998-01-01

    In the ongoing search for alternative and environmental friendly power generation facilities, the fuel cell is a good candidate. There are several types of fuel cells with large differences in application, size, cost and operating range. The Solid Oxide Fuel Cell (SOFC) is a high temperature fuel

  6. The Effect of H2S on the Performance of SOFCs using Methane Containing Fuel

    DEFF Research Database (Denmark)

    Rasmussen, Jens Foldager Bregnballe; Hagen, Anke

    2010-01-01

    In recent years, the interest for using biogas derived from biomass as fuel in solid oxide fuel cells (SOFCs) has increased. To maximise the biogas to electrical energy output, it is important to study the effects of the main biogas components (CH4 and CO2), minor ones and traces (e.g. H2S...

  7. Thermodynamic analysis and optimization of IT-SOFC-based integrated coal gasification fuel cell power plants

    NARCIS (Netherlands)

    Romano, M.C.; Campanari, S.; Spallina, V.; Lozza, G.

    2011-01-01

    This work discusses the thermodynamic analysis of integrated gasification fuel cell plants, where a simple cycle gas turbine works in a hybrid cycle with a pressurized intermediate temperature–solid oxide fuel cell (SOFC), integrated with a coal gasification and syngas cleanup island and a bottoming

  8. The financial viability of an SOFC cogeneration system in single-family dwellings

    Science.gov (United States)

    Alanne, Kari; Saari, Arto; Ugursal, V. Ismet; Good, Joel

    In the near future, fuel cell-based residential micro-CHP systems will compete with traditional methods of energy supply. A micro-CHP system may be considered viable if its incremental capital cost compared to its competitors equals to cumulated savings during a given period of time. A simplified model is developed in this study to estimate the operation of a residential solid oxide fuel cell (SOFC) system. A comparative assessment of the SOFC system vis-à-vis heating systems based on gas, oil and electricity is conducted using the simplified model for a single-family house located in Ottawa and Vancouver. The energy consumption of the house is estimated using the HOT2000 building simulation program. A financial analysis is carried out to evaluate the sensitivity of the maximum allowable capital cost with respect to system sizing, acceptable payback period, energy price and the electricity buyback strategy of an energy utility. Based on the financial analysis, small (1-2 kW e) SOFC systems seem to be feasible in the considered case. The present study shows also that an SOFC system is especially an alternative to heating systems based on oil and electrical furnaces.

  9. Control-relevant modeling and simulation of a SOFC-GT hybrid system

    Directory of Open Access Journals (Sweden)

    Rambabu Kandepu

    2006-07-01

    Full Text Available In this paper, control-relevant models of the most important components in a SOFC-GT hybrid system are described. Dynamic simulations are performed on the overall hybrid system. The model is used to develop a simple control structure, but the simulations show that more elaborate control is needed.

  10. Control-relevant modeling and simulation of a SOFC-GT hybrid system

    OpenAIRE

    Rambabu Kandepu; Lars Imsland; Christoph Stiller; Bjarne A. Foss; Vinay Kariwala

    2006-01-01

    In this paper, control-relevant models of the most important components in a SOFC-GT hybrid system are described. Dynamic simulations are performed on the overall hybrid system. The model is used to develop a simple control structure, but the simulations show that more elaborate control is needed.

  11. Thermo-mechanical properties of SOFC components investigated by a combined method

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Esposito, Vincenzo; Ramousse, Severine

    , and differential thermo-mechanical behavior at each layer. The combination of such factors can have a critical effect on the final shape and microstructure, and on the mechanical integrity. Thermo-mechanical properties and sintering mechanisms of important SOFC materials (CGO, YSZ, ScYSZ) were systematically...

  12. Cr-tolerance of the IT-SOFC La(Ni,Fe)O3 material

    NARCIS (Netherlands)

    Stodolny, M.K.

    2012-01-01

    This thesis deals with a study on the Cr-tolerance of the LaNi0.6Fe0.4O3 (LNF) material. LNF is being considered for use as a current collecting layer, an interconnect protective coating and/or an electrochemically active solid oxide fuel cell (SOFC) cathode layer in an intermediate temperature

  13. A SOFC-based integrated gasification fuel cell cycle with CO2 capture

    NARCIS (Netherlands)

    Spallina, V.; Romano, M.C.; Campanari, S.; Lozza, G.

    2011-01-01

    The application of solid oxide fuel cells (SOFC) in gasification-based power plants would represent a turning point in the power generation sector, allowing to considerably increase the electric efficiency of coal-fired power stations. Pollutant emissions would also be significantly reduced in

  14. Effect of Samarium Oxide on the Electrical Conductivity of Plasma-Sprayed SOFC Anodes

    Science.gov (United States)

    Panahi, S. N.; Samadi, H.; Nemati, A.

    2016-10-01

    Solid oxide fuel cells (SOFCs) are rapidly becoming recognized as a new alternative to traditional energy conversion systems because of their high energy efficiency. From an ecological perspective, this environmentally friendly technology, which produces clean energy, is likely to be implemented more frequently in the future. However, the current SOFC technology still cannot meet the demands of commercial applications due to temperature constraints and high cost. To develop a marketable SOFC, suppliers have tended to reduce the operating temperatures by a few hundred degrees. The overall trend for SOFC materials is to reduce their service temperature of electrolyte. Meanwhile, it is important that the other components perform at the same temperature. Currently, the anodes of SOFCs are being studied in depth. Research has indicated that anodes based on a perovskite structure are a more promising candidate in SOFCs than the traditional system because they possess more favorable electrical properties. Among the perovskite-type oxides, SrTiO3 is one of the most promising compositions, with studies demonstrating that SrTiO3 exhibits particularly favorable electrical properties in contrast with other perovskite-type oxides. The main purpose of this article is to describe our study of the effect of rare-earth dopants with a perovskite structure on the electrical behavior of anodes in SOFCs. Sm2O3-doped SrTiO3 synthesized by a solid-state reaction was coated on substrate by atmospheric plasma spray. To compare the effect of the dopant on the electrical conductivity of strontium titanate, different concentrations of Sm2O3 were used. The samples were then investigated by x-ray diffraction, four-point probe at various temperatures (to determine the electrical conductivity), and a scanning electron microscope. The study showed that at room temperature, nondoped samples have a higher electrical resistance than doped samples. As the temperature was increased, the electrical

  15. Performance analysis of a co-generation system using solar energy and SOFC technology

    International Nuclear Information System (INIS)

    Akikur, R.K.; Saidur, R.; Ping, H.W.; Ullah, K.R.

    2014-01-01

    Highlights: • A new concept of a cogeneration system is proposed and investigated. • The system comprises solar collector, PV, SOFC and heat exchanger. • 83.6% Power and heat generation efficiency has been found at fuel cell mode. • 85.1% Efficiency of SOSE has been found at H2 production mode. • The heat to power ratio of SOFC mode has been found about 0.917. - Abstract: Due to the increasing future energy demands and global warming, the renewable alternative energy sources and the efficient power systems have been getting importance over the last few decades. Among the renewable energy technologies, the solar energy coupling with fuel cell technology will be the promising possibilities for the future green energy solutions. Fuel cell cogeneration is an auspicious technology that can potentially reduce the energy consumption and environmental impact associated with serving building electrical and thermal demands. In this study, performance assessment of a co-generation system is presented to deliver electrical and thermal energy using the solar energy and the reversible solid oxide fuel cell. A mathematical model of the co-generation system is developed. To illustrate the performance, the system is considered in three operation modes: a solar-solid oxide fuel cell (SOFC) mode, which is low solar radiation time when the solar photovoltaic (PV) and SOFC are used for electric and heat load supply; a solar-solid oxide steam electrolyzer (SOSE) mode, which is high solar radiation time when PV is used for power supply to the electrical load and to the steam electrolyzer to generate hydrogen (H 2 ); and a SOFC mode, which is the power and heat generation mode of reversible SOFC using the storage H 2 at night time. Also the effects of solar radiation on the system performances and the effects of temperature on RSOFC are analyzed. In this study, 100 kW electric loads are considered and analyzed for the power and heat generation in those three modes to evaluate

  16. The planar cubic Cayley graphs

    CERN Document Server

    Georgakopoulos, Agelos

    2018-01-01

    The author obtains a complete description of the planar cubic Cayley graphs, providing an explicit presentation and embedding for each of them. This turns out to be a rich class, comprising several infinite families. He obtains counterexamples to conjectures of Mohar, Bonnington and Watkins. The author's analysis makes the involved graphs accessible to computation, corroborating a conjecture of Droms.

  17. Casimir stress inside planar materials

    Science.gov (United States)

    Griniasty, Itay; Leonhardt, Ulf

    2017-09-01

    The Casimir force between macroscopic bodies is well understood, but not the Casimir force inside bodies. Guided by a physically intuitive picture, we develop the macroscopic theory of the renormalized Casimir stress inside planar materials (where the electromagnetic properties vary in one direction). Our theory may be applied in predicting how inhomogeneous fluids respond to Casimir forces.

  18. Approximation by planar elastic curves

    DEFF Research Database (Denmark)

    Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge

    2016-01-01

    We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient......-driven optimization is then used to find the approximating elastic curve....

  19. Poling of Planar Silica Waveguides

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Jensen, Jesper Bo

    1999-01-01

    UV-written planar silica waveguides are poled using two different poling techniques, thermal poling and UV-poling. Thermal poling induces an electro-optic coefficient of 0.067 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. The induced electro-optic effect shows a linear dependence...

  20. Use of wastewater treatment plant biogas for the operation of Solid Oxide Fuel Cells (SOFCs).

    Science.gov (United States)

    Lackey, Jillian; Champagne, Pascale; Peppley, Brant

    2017-12-01

    Solid Oxide Fuel Cells (SOFCs) perform well on light hydrocarbon fuels, and the use of biogas derived from the anaerobic digestion (AD) of municipal wastewater sludges could provide an opportunity for the CH 4 produced to be used as a renewable fuel. Greenhouse gas (GHG), NO x , SO x , and hydrocarbon pollutant emissions would also be reduced. In this study, SOFCs were operated on AD derived biogas. Initially, different H 2 dilutions were tested (N 2 , Ar, CO 2 ) to examine the performance of tubular SOFCs. With inert gases as diluents, a decrease in cell performance was observed, however, the use of CO 2 led to a higher decrease in performance as it promoted the reverse water-gas shift (WGS) reaction, reducing the H 2 partial pressure in the gas mixture. A model was developed to predict system efficiency and GHG emissions. A higher electrical system efficiency was noted for a steam:carbon ratio of 2 compared to 1 due to the increased H 2 partial pressure in the reformate resulting from higher H 2 O concentration. Reductions in GHG emissions were estimated at 2400 tonnes CO 2 , 60 kg CH 4 and 18 kg N 2 O. SOFCs were also tested using a simulated biogas reformate mixture (66.7% H 2 , 16.1% CO, 16.5% CO 2 , 0.7% N 2 , humidified to 2.3 or 20 mol% H 2 O). Higher humidification yielded better performance as the WGS reaction produced more H 2 with additional H 2 O. It was concluded that AD-derived biogas, when cleaned to remove H 2 S, Si compounds, halides and other contaminants, could be reformed to provide a clean, renewable fuel for SOFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

    Science.gov (United States)

    Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

    2010-01-01

    High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

  2. Ultrathin Planar Graphene Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jingsong [ORNL; Meunier, Vincent [ORNL; Sumpter, Bobby G [ORNL; Ajayan, Pullikel M [Rice University; Yoo, Jung Joon [KAIST, Daejeon, Republic of Korea; Balakrishnan, Kaushik [Rice University; Srivastava, Anchal [Rice University; Conway, Michelle [Rice University; Reddy, Arava Leela Mohan [Rice University; Yu, Jin [Rice University; Vajtai, Robert [Rice University

    2011-01-01

    With the advent of atomically thin and flat layers of conducting materials such as graphene, new designs for thin film energy storage devices with good performance have become possible. Here, we report an in-plane fabrication approach for ultrathin supercapacitors based on electrodes comprised of pristine graphene and multi-layer reduced graphene oxide. The in-plane design is straightforward to implement and exploits efficiently the surface of each graphene layer for energy storage. The open architecture and the effect of graphene edges enable even the thinnest of devices, made from as grown 1-2 graphene layers, to reach specific capacities up to 80 Fcm-2. While, much higher (394 Fcm-2) specific capacities are observed in case of multi-layered graphene oxide electrodes, owing to the better utilization of the available electrochemical surface area. The performances of devices with pristine as well as thicker graphene based structures are examined using a combination of experiments and model calculations. The demonstrated all solid-state supercapacitors provide a prototype for a broad range of thin-film based energy storage devices.

  3. Chemistry of SOFC Cathode Surfaces: Fundamental Investigation and Tailoring of Electronic Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, Bilge; Heski, Clemens

    2013-08-31

    1) Electron tunneling characteristics on La0.7Sr0.3MnO3 (LSM) thin-film surfaces were studied up to 580oC in 10-3mbar oxygen pressure, using scanning tunneling microscopy/ spectroscopy (STM/STS). A threshold-like drop in the tunneling current was observed at positive bias in STS, which is interpreted as a unique indicator for the activation polarization in cation oxygen bonding on LSM cathodes. Sr-enrichment was found on the surface at high temperature using Auger electron spectroscopy, and was accompanied by a decrease in tunneling conductance in STS. This suggests that Sr-terminated surfaces are less active for electron transfer in oxygen reduction compared to Mn-terminated surfaces on LSM. 2) Effects of strain on the surface cation chemistry and the electronic structure are important to understand and control for attaining fast oxygen reduction kinetics on transition metal oxides. Here, we demonstrate and mechanistically interpret the strain coupling to Sr segregation, oxygen vacancy formation, and electronic structure on the surface of La0.7Sr0.3MnO3 (LSM) thin films as a model system. Our experimental results from x-ray photoelectron spectroscopy and scanning tunneling spectroscopy are discussed in light of our first principles-based calculations. A stronger Sr enrichment tendency and a more facile oxygen vacancy formation prevail for the tensile strained LSM surface. The electronic structure of the tensile strained LSM surface exhibits a larger band gap at room temperature, however, a higher tunneling conductance near the Fermi level than the compressively strained LSM at elevated temperatures in oxygen. Our findings suggest lattice strain as a key parameter to tune the reactivity of perovskite transition metal oxides with oxygen in solid oxide fuel cell cathodes. 3) Cation segregation on perovskite oxide surfaces affects vastly the oxygen reduction activity and stability of solid oxide fuel cell (SOFC) cathodes. A unified theory that explains the physical

  4. Synthesis and application of aryl-ferrocenyl(pseudo-biarylic) complexes. Part 5. Design and synthesis of a new type of ferrocene-based planar chiral DMAP analogues. A new catalyst system for asymmetric nucleophilic catalysis

    DEFF Research Database (Denmark)

    Seitzberg, J.G; Dissing, C; Søtofte, Inger

    2005-01-01

    A new first-generation catalyst system for nucleophilic catalysis has been developed. It is based on a planar chiral ferrocene skeleton with either the potent nucleophile 4-(dimethylamino)pyridine (DMAP) or the related 4-nitropyridine N-oxide attached in either the 2- or the 3-position. The synth......A new first-generation catalyst system for nucleophilic catalysis has been developed. It is based on a planar chiral ferrocene skeleton with either the potent nucleophile 4-(dimethylamino)pyridine (DMAP) or the related 4-nitropyridine N-oxide attached in either the 2- or the 3-position...

  5. Singler-chamber SOFCs based on gadolinia doped ceria operated on methane and propane; Pilas de combustible de una sola camara, basadas en electrolitos de ceria dopada con gadolinia y operadas con metano y propano

    Energy Technology Data Exchange (ETDEWEB)

    Morales, M.; Roa, J. J.; Capdevila, X. G.; Segarra, M.; Pinol, S.

    2010-07-01

    The main advantages of single-chamber solid oxide fuel cells (SOFCs) respect to dual-chamber SOFCs, are to simplify the device design and to operate in mixtures of hydrocarbon (methane, propane...) and air, with no separation between fuel and oxidant. However, this design requires the use of selective electrodes for the fuel oxidation and the oxidant reduction. In this work, electrolyte-supported SOFCs were fabricated using gadolinia doped ceria (GDC) as the electrolyte, Ni + GDC as the anode and LSC(La{sub 0}.5Sr{sub 0}.5CoO{sub 3}-{delta})-GDC-Ag{sub 2}O as the cathode. The electrical properties of the cell were determined in mixtures of methane + air and propane + air. The influence of temperature, gas composition and total flow rate on the fuel cell performance was investigated. As a result, the power density was strongly increased with increasing temperature, total flow rate and hydrocarbon composition. Under optimized gas compositions and total flow conditions, power densities of 70 and 320 mW/cm{sup 2} operating on propane at a temperature of 600 degree centigrade and methane (795 degree centigrade) were obtained, respectively. (Author)

  6. MCM Polarimetric Radiometers for Planar Arrays

    Science.gov (United States)

    Kangaslahti, Pekka; Dawson, Douglas; Gaier, Todd

    2007-01-01

    A polarimetric radiometer that operates at a frequency of 40 GHz has been designed and built as a prototype of multiple identical units that could be arranged in a planar array for scientific measurements. Such an array is planned for use in studying the cosmic microwave background (CMB). All of the subsystems and components of this polarimetric radiometer are integrated into a single multi-chip module (MCM) of substantially planar geometry. In comparison with traditional designs of polarimetric radiometers, the MCM design is expected to greatly reduce the cost per unit in an array of many such units. The design of the unit is dictated partly by a requirement, in the planned CMB application, to measure the Stokes parameters I, Q, and U of the CMB radiation with high sensitivity. (A complete definition of the Stokes parameters would exceed the scope of this article. In necessarily oversimplified terms, I is a measure of total intensity of radiation, while Q and U are measures of the relationships between the horizontally and vertically polarized components of radiation.) Because the sensitivity of a single polarimeter cannot be increased significantly, the only way to satisfy the high-sensitivity requirement is to make a large array of polarimeters that operate in parallel. The MCM includes contact pins that can be plugged into receptacles on a standard printed-circuit board (PCB). All of the required microwave functionality is implemented within the MCM; any required supporting non-microwave ("back-end") electronic functionality, including the provision of DC bias and control signals, can be implemented by standard PCB techniques. On the way from a microwave antenna to the MCM, the incoming microwave signal passes through an orthomode transducer (OMT), which splits the radiation into an h + i(nu) beam and an h - i(nu) beam (where, using complex-number notation, h denotes the horizontal component, nu denotes the vertical component, and +/-i denotes a +/-90deg phase

  7. Planar passive electromagnetic deflector for millimeter-wave frequencies

    NARCIS (Netherlands)

    Kastelijn, M.C.T.; Akkermans, J.A.G.

    2008-01-01

    A novel passive planar structure is proposed that is able to deflect an incoming electromagnetic (EM) wave into a desired direction. The direction of the outgoing EM wave is determined by the design of this deflector. The deflector can be used to extend coverage of a steerable source with limited

  8. Planar concentrators at the étendue limit

    Science.gov (United States)

    Winston, Roland; Gordon, Jeffrey M.

    2005-08-01

    Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultra-compact planar dielectric-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multi-junction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm2 cell.

  9. Characterization of a planar microcoil for implantable microsystems

    NARCIS (Netherlands)

    Neagu, Cristina; Rusu, C.R.; Jansen, Henricus V.; Smith, A.; Gardeniers, Johannes G.E.; Elwenspoek, Michael Curt

    This paper discusses the modelling, design and characterization of planar microcoils to be used in telemetry systems that supply energy to miniaturized implants. Parasitic electrical effects that may become important at a.c. frequencies of several megahertz are evaluated. The fabrication process and

  10. A planar microfluidic mixer based on logarithmic spirals

    International Nuclear Information System (INIS)

    Scherr, Thomas; Nandakumar, Krishnaswamy; Quitadamo, Christian; Tesvich, Preston; Park, Daniel Sang-Won; Hayes, Daniel; Monroe, W Todd; Tiersch, Terrence; Choi, Jin-Woo

    2012-01-01

    A passive, planar micromixer design based on logarithmic spirals is presented. The device was fabricated using polydimethylsiloxane soft photolithography techniques, and mixing performance was characterized via numerical simulation and fluorescent microscopy. Mixing efficiency initially declined as the Reynolds number increased, and this trend continued until a Reynolds number of 15 where a minimum was reached at 53%. Mixing efficiency then began to increase reaching a maximum mixing efficiency of 86% at Re = 67. Three-dimensional (3D) simulations of fluid mixing in this design were compared to other planar geometries such as the Archimedes spiral and Meandering-S mixers. The implementation of logarithmic curvature offers several unique advantages that enhance mixing, namely a variable cross-sectional area and a logarithmically varying radius of curvature that creates 3D Dean vortices. These flow phenomena were observed in simulations with multilayered fluid folding and validated with confocal microscopy. This design provides improved mixing performance over a broader range of Reynolds numbers than other reported planar mixers, all while avoiding external force fields, more complicated fabrication processes and the introduction of flow obstructions or cavities that may unintentionally affect sensitive or particulate-containing samples. Due to the planar design requiring only single-step lithographic features, this compact geometry could be easily implemented into existing micro-total analysis systems requiring effective rapid mixing. (paper)

  11. Planar-Processed Polymer Transistors.

    Science.gov (United States)

    Xu, Yong; Sun, Huabin; Shin, Eul-Yong; Lin, Yen-Fu; Li, Wenwu; Noh, Yong-Young

    2016-10-01

    Planar-processed polymer transistors are proposed where the effective charge injection and the split unipolar charge transport are all on the top surface of the polymer film, showing ideal device characteristics with unparalleled performance. This technique provides a great solution to the problem of fabrication limitations, the ambiguous operating principle, and the performance improvements in practical applications of conjugated-polymer transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Application of holographic elements in displays and planar illuminators

    Science.gov (United States)

    Putilin, Andrew; Gustomiasov, Igor

    2007-05-01

    Holographic Optical Elements (HOE's) on planar waveguides can be used to design the planar optics for backlit units, color selectors or filters, lenses for virtual reality displays. The several schemes for HOE recording are proposed to obtain planar stereo backlit unit and private eye displays light source. It is shown in the paper that the specific light transformation grating permits to construct efficient backlit units for display holograms and LCD. Several schemes of reflection/transmission backlit units and scattering films based on holographic optical elements are also proposed. The performance of the waveguide HOE can be optimized using the parameters of recording scheme and etching parameters. The schemes of HOE application are discussed and some experimental results are shown.

  13. Planar patch clamp: advances in electrophysiology.

    Science.gov (United States)

    Brüggemann, Andrea; Farre, Cecilia; Haarmann, Claudia; Haythornthwaite, Ali; Kreir, Mohamed; Stoelzle, Sonja; George, Michael; Fertig, Niels

    2008-01-01

    Ion channels have gained increased interest as therapeutic targets over recent years, since a growing number of human and animal diseases have been attributed to defects in ion channel function. Potassium channels are the largest and most diverse family of ion channels. Pharmaceutical agents such as Glibenclamide, an inhibitor of K(ATP) channel activity which promotes insulin release, have been successfully sold on the market for many years. So far, only a small group of the known ion channels have been addressed as potential drug targets. The functional testing of drugs on these ion channels has always been the bottleneck in the development of these types of pharmaceutical compounds.New generations of automated patch clamp screening platforms allow a higher throughput for drug testing and widen this bottleneck. Due to their planar chip design not only is a higher throughput achieved, but new applications have also become possible. One of the advantages of planar patch clamp is the possibility of perfusing the intracellular side of the membrane during a patch clamp experiment in the whole-cell configuration. Furthermore, the extracellular membrane remains accessible for compound application during the experiment.Internal perfusion can be used not only for patch clamp experiments with cell membranes, but also for those with artificial lipid bilayers. In this chapter we describe how internal perfusion can be applied to potassium channels expressed in Jurkat cells, and to Gramicidin channels reconstituted in a lipid bilayer.

  14. Reversibility of the SOFC for the hydrogen production by high temperature electrolysis; Reversibilite des SOFC pour la production d'hydrogene par electrolyse haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Brisse, A.; Marrony, M.; Perednis, D.; Schefold, J.; Jose-Garcia, M.; Zahid, M. [Institut Europeen de Recherche sur l' Energie (EIFER), Karlsruhe (Germany)

    2007-07-01

    The behaviour of two SOFC cells in electrolysis mode is studied. The performances of these solid oxide cells, reversible at 800 C and for current densities between 0 and -0.42 A/cm{sup 2}, are presented. A weaker polarisation resistance has been measured for the cell containing a mixed conductor as oxygen electrode. For each cell, a limitation by gaseous diffusion has been observed under current. This phenomenon appears for current densities which are higher for the mixed conductor cell as oxygen electrode. (O.M.)

  15. Feasibility study for SOFC-GT hybrid locomotive power: Part I. Development of a dynamic 3.5 MW SOFC-GT FORTRAN model

    OpenAIRE

    Martinez, AS; Brouwer, J; Samuelsen, GS

    2012-01-01

    This work presents the development of a dynamic SOFC-GT hybrid system model applied to a long-haul freight locomotive in operation. Given the expectations of the rail industry, the model is used to develop a preliminary analysis of the proposed system's operational capability on conventional diesel fuel as well as natural gas and hydrogen as potential fuels in the future. It is found that operation of the system on all three of these fuels is feasible with favorable efficiencies and reasonabl...

  16. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin

    International Nuclear Information System (INIS)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O.

    2016-01-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca_3Co_4O_9, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  17. Ag as an alternative for Ni in direct hydrocarbon SOFC anodes

    Energy Technology Data Exchange (ETDEWEB)

    Cantos-Gomez, A.; Van Duijn, J. [Instituto de Energias Renovables, Universidad de Castilla La Mancha, Paseo de la Investigacion 1, 02006 Albacete (Spain); Ruiz-Bustos, R. [Instituto de Energias Renovables, Parque Cientifico y Tecnologico de Albacete, Paseo de la Investigacion 1, 02006 Albacete (Spain)

    2011-02-15

    Ag has been shown to be a good metal for SOFC anode cermets using CO fuel. Here we have expanded on the work reported by testing Ag-YSZ cermets against different hydrocarbon based fuel (H{sub 2} and CH{sub 4}). This study shows that while Ag is a good current collector, it alone does not have the required catalytic activity for the direct oxidation of hydrocarbon based fuels needed to be used in SOFC anodes. As such an additional catalytic material (e.g. CeO{sub 2}) needs to be present when using fuels other then CO. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Effect of load transients on SOFC operation—current reversal on loss of load

    Science.gov (United States)

    Gemmen, Randall S.; Johnson, Christopher D.

    The dynamics of solid oxide fuel cell (SOFC) operation have been considered previously, but mainly through the use of one-dimensional codes applied to co-flow fuel cell systems. In this paper several geometries are considered, including cross-flow, co-flow, and counter-flow. The details of the model are provided, and the model is compared with some initial experimental data. For parameters typical of SOFC operation, a variety of transient cases are investigated, including representative load increase and decrease and system shutdown. Of particular note for large load decrease conditions (e.g., shutdown) is the occurrence of reverse current over significant portions of the cell, starting from the moment of load loss up to the point where equilibrated conditions again provide positive current. Consideration is given as to when such reverse current conditions might most significantly impact the reliability of the cell.

  19. Preparation of thin layer materials with macroporous microstructure for SOFC applications

    International Nuclear Information System (INIS)

    Marrero-Lopez, D.; Ruiz-Morales, J.C.; Pena-Martinez, J.; Canales-Vazquez, J.; Nunez, P.

    2008-01-01

    A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range. - Graphical abstract: Thin films materials of mixed oxides with potential application in SOFC devices have been prepared with macroporous microstructure using PMMA microspheres as pore formers. Display Omitted

  20. Total cost of ownership of CHP SOFC systems: Effect of installation context

    International Nuclear Information System (INIS)

    Arduino, Francesco; Santarelli, Massimo

    2016-01-01

    Solid oxide fuel cells (SOFC) are one of the most interesting between the emerging technologies for energy production. Although some information about the production cost of these devices are already known, their operational cost has not been studied yet with sufficient accuracy. This paper presents a life cycle cost (LCC) analysis of CHP (combined heat and power) SOFC systems performed in hospitals located in various cities of the US and one in Italy. In this study the strong effects of the installation context will be analyzed using a customized use phase model for each location. The cost effectiveness of these devices has been proved without credits in Mondovi (IT), New York (NY) and Minneapolis (MN) where the payback time goes from 10 to 7 years. Considering the credits, it is possible to obtain economic feasibility also in Chicago (IL) and reduce the payback for other cities to values from 4 to 6 years. In other cities like Phoenix (AZ) and Houston (TX) the payback can’t be reached in any case. The life cycle impact assessment analysis has shown how, even in the cities with cleaner electricity grid, there is a reduction in the emissions of both greenhouse gases and pollutants. - Highlights: •Life cycle cost analysis has been performed for CHP SOFC systems. •The strong effects of the installation context have been analyzed. •Economic feasibility has been proven in new york, Minneapolis and Mondovi. •Economic feasibility can’t be reached in phoenix and Houston. •SOFC always provide a reduction in the emissions of greenhouse gases and pollutant.

  1. The design of stationary and mobile solid oxide fuel cell-gas turbine systems

    Science.gov (United States)

    Winkler, Wolfgang; Lorenz, Hagen

    A general thermodynamic model has shown that combined fuel cell cycles may reach an electric-efficiency of more than 80%. This value is one of the targets of the Department of Energy (DOE) solid oxide fuel cell-gas turbine (SOFC-GT) program. The combination of a SOFC and GT connects the air flow of the heat engine and the cell cooling. The principle strategy in order to reach high electrical-efficiencies is to avoid a high excess air for the cell cooling and heat losses. Simple combined SOFC-GT cycles show an efficiency between 60 and 72%. The combination of the SOFC and the GT can be done by using an external cooling or by dividing the stack into multiple sub-stacks with a GT behind each sub-stack as the necessary heat sink. The heat exchangers (HEXs) of a system with an external cooling have the benefit of a pressurization on both sides and therefore, have a high heat exchange coefficient. The pressurization on both sides delivers a low stress to the HEX material. The combination of both principles leads to a reheat (RH)-SOFC-GT cycle that can be improved by a steam turbine (ST) cycle. The first results of a study of such a RH-SOFC-GT-ST cycle indicate that a cycle design with an efficiency of more than 80% is possible and confirm the predictions by the theoretical thermodynamic model mentioned above. The extremely short heat-up time of a thin tubular SOFC and the market entrance of the micro-turbines give the option of using these SOFC-GT designs for mobile applications. The possible use of hydrocarbons such as diesel oil is an important benefit of the SOFC. The micro-turbine and the SOFC stack will be matched depending on the start-up requirements of the mobile system. The minimization of the volume needed is a key issue. The efficiency of small GTs is lower than the efficiency of large GTs due to the influence of the leakage within the stages of GTs increasing with a decreasing size of the GT. Thus, the SOFC module pressure must be lower than in larger

  2. Effect of interlayer on structure and performance of anode-supported SOFC single cells

    International Nuclear Information System (INIS)

    Eom, Tae Wook; Yang, Hae Kwang; Kim, Kyung Hwan; Yoon, Hyon Hee; Kim, Jong Sung; Park, Sang Joon

    2008-01-01

    To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57 W/cm 2 at 800 deg. C and 0.44 W/cm 2 at 700 deg. C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer

  3. Simulation and Parametric Analysis of a Hybrid SOFC-Gas Turbine Power Generation System

    International Nuclear Information System (INIS)

    Hassan, A.M.; Fahmy

    2004-01-01

    Combined SOFC-Gas Turbine Power Generation Systems are aimed to increase the power and efficiency obtained from the technology of using high temperature fuel cells by integrating them with gas turbines. Hybrid systems are considered in the last few years as one of the most promising technologies to obtain electric energy from the natural gas at very high efficiency with a serious potential for commercial use. The use of high temperature allows internal reforming for natural gas and thus disparity of fuel composition is allowed. Also air preheating is performed thanks to the high operating cell temperature as a task of energy integration. In this paper a modeling approach is presented for the fuel cell-gas turbine hybrid power generation systems, to obtain the sofc output voltage, power, and the overall hybrid system efficiency. The system has been simulated using HYSYS, the process simulation software to help improving the process understanding and provide a quick system solution. Parametric analysis is also presented in this paper to discuss the effect of some important SOFC operating parameters on the system performance and efficiency

  4. Planar channeling in superlattices: Theory

    International Nuclear Information System (INIS)

    Ellison, J.A.; Picraux, S.T.; Allen, W.R.; Chu, W.K.

    1988-01-01

    The well-known continuum model theory for planar channeled energetic particles in perfect crystals is extended to layered crystalline structures and applied to superlattices. In a strained-layer structure, the planar channels with normals which are not perpendicular to the growth direction change their direction at each interface, and this dramatically influences the channeling behavior. The governing equation of motion for a planar channeled ion in a strained-layer superlattice with equal layer thicknesses is a one degree of freedom nonlinear oscillator which is periodically forced with a sequence of δ functions. These δ functions, which are of equal spacing and amplitude with alternating sign, represent the tilts at each of the interfaces. Thus upon matching an effective channeled particle wavelength, corresponding to a natural period of the nonlinear oscillator, to the period of the strained-layer superlattice, corresponding to the periodic forcing, strong resonance effects are expected. The condition of one effective wavelength per period corresponds to a rapid dechanneling at a well-defined depth (catastrophic dechanneling), whereas two wavelengths per period corresponds to no enhanced dechanneling after the first one or two layers (resonance channeling). A phase plane analysis is used to characterize the channeled particle motion. Detailed calculations using the Moliere continuum potential are compared with our previously described modified harmonic model, and new results are presented for the phase plane evolution, as well as the dechanneling as a function of depth, incident angle, energy, and layer thickness. General scaling laws are developed and nearly universal curves are obtained for the dechanneling versus depth under catastrophic dechanneling

  5. Nonlinear control methods for planar carangiform robot fish locomotion

    OpenAIRE

    Morgansen, Kristi A.; Duindam, Vincent; Mason, Richard J.; Burdick, Joel W.; Murray, Richard M.

    2001-01-01

    Considers the design of motion control algorithms for robot fish. We present modeling, control design, and experimental trajectory tracking results for an experimental planar robotic fish system that is propelled using carangiform-like locomotion. Our model for the fish's propulsion is based on quasi-steady fluid flow. Using this model, we propose gaits for forward and turning trajectories and analyze system response under such control strategies. Our models and predictions are verified by ex...

  6. Planar concentrators near the étendue limit.

    Science.gov (United States)

    Winston, Roland; Gordon, Jeffrey M

    2005-10-01

    Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultracompact planar glass-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multijunction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm2 cell. When deployed in reverse, our designs provide collimation even for high-numerical-aperture light sources.

  7. Planar concentrators near the étendue limit

    Science.gov (United States)

    Winston, Roland; Gordon, Jeffrey M.

    2005-10-01

    Recently proposed aplanatic imaging designs are integrally combined with nonimaging flux boosters to produce an ultracompact planar glass-filled concentrator that performs near the étendue limit. Such optical devices are attractive for high-efficiency multijunction photovoltaics at high flux, with realistic power generation of 1 W from a 1 mm² cell. When deployed in reverse, our designs provide collimation even for high-numerical-aperture light sources.

  8. Development of a Low Cost 10kW Tubular SOFC Power System

    Energy Technology Data Exchange (ETDEWEB)

    Bessette, Norman [Acumentrics Corporation, Westwood, MA (United States); Litka, Anthony [Acumentrics Corporation, Westwood, MA (United States); Rawson, Jolyon [Acumentrics Corporation, Westwood, MA (United States); Schmidt, Douglas [Acumentrics Corporation, Westwood, MA (United States)

    2013-06-06

    The DOE program funded from 2003 through early 2013 has brought the Acumentrics SOFC program from an early stage R&D program to an entry level commercial product offering. The development work started as one of the main core teams under the DOE Solid State Energy Conversion Alliance (SECA) program administered by the National Energy Technology Laboratory (NETL) of the DOE. During the first phase of the program, lasting approximately 3-4 years, a 5kW machine was designed, manufactured and tested against the specification developed by NETL. This unit was also shipped to NETL for independent verification testing which validated all of the results achieved while in the laboratory at Acumentrics. The Acumentrics unit passed all criteria established from operational stability, efficiency, and cost projections. Passing of the SECA Phase I test allowed the program to move into Phase II of the program. During this phase, the overall objective was to further refine the unit meeting a higher level of performance stability as well as further cost reductions. During the first year of this new phase, the NETL SECA program was refocused towards larger size units and operation on coal gasification due to the severe rise in natural gas prices and refocus on the US supply of indigenous coal. At this point, the program was shifted to the U.S. DOE’s Energy Efficiency and Renewable Energy (EERE) division located in Golden, Colorado. With this shift, the focus remained on smaller power units operational on gaseous fuels for a variety of applications including micro combined heat and power (mCHP). To achieve this goal, further enhancements in power, life expectancy and reductions in cost were necessary. The past 5 years have achieved these goals with machines that can now achieve over 40% electrical efficiency and field units that have now operated for close to a year and a half with minimal maintenance. The following report details not only the first phase while under the SECA program

  9. Non-planar ABJ theory and parity

    International Nuclear Information System (INIS)

    Caputa, Pawel; Kristjansen, Charlotte; Zoubos, Konstantinos

    2009-01-01

    While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ABJ theory is parity invariant. In this Letter we derive the non-planar part of the two-loop dilatation generator of ABJ theory in its SU(2)xSU(2) sub-sector. Applying the dilatation generator to short operators, we explicitly demonstrate that, for operators carrying excitations on both spin chains, the non-planar part breaks parity invariance. For operators with only one type of excitation, however, parity remains conserved at the non-planar level. We furthermore observe that, as for ABJM theory, the degeneracy between planar parity pairs is lifted when non-planar corrections are taken into account.

  10. Modeling the planar configuration of extraordinary magnetoresistance

    International Nuclear Information System (INIS)

    El-Ahmar, S; Pozniak, A A

    2015-01-01

    Recently the planar version of the extraordinary magnetoresistance (EMR) magnetic field sensor has been constructed and verified in practice. Planar configuration of the EMR device gives many technological advantages, it is simpler than the classic and allows one to build the sensor using electric materials of the new type (such as graphene or topological insulators) much easier. In this work the planar configuration of the EMR sensor is investigated by performing computational simulations using the finite element method (FEM). The computational comparison of the planar and classic configurations of EMR is presented using three-dimensional models. Various variants of the geometry of EMR sensor components are pondered and compared in the planar and classic version. Size of the metal overlap is considered for sensor optimization as well as various semiconductor-metal contact resistance dependences of the EMR signal. Based on computational simulations, a method for optimal placement of electric terminals in a planar EMR device is proposed. (paper)

  11. Non-planar ABJ Theory and Parity

    DEFF Research Database (Denmark)

    Caputa, Pawel; Kristjansen, Charlotte; Zoubos, Konstantinos

    2009-01-01

    we derive the non-planar part of the two-loop dilatation generator of ABJ theory in its SU(2)xSU(2) sub-sector. Applying the dilatation generator to short operators, we explicitly demonstrate that, for operators carrying excitations on both spin chains, the non-planar part breaks parity invariance......While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ABJ theory is parity invariant. In this letter....... For operators with only one type of excitation, however, parity remains conserved at the non-planar level. We furthermore observe that, as for ABJM theory, the degeneracy between planar parity pairs is lifted when non-planar corrections are taken into account....

  12. KAPPEL Propeller. Development of a Marine Propeller with Non-planar Lifting Surfaces

    DEFF Research Database (Denmark)

    Kappel, J.; Andersen, Poul

    2002-01-01

    The principle of non-planar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or "winglet" at the wingtip has been developed for aircraft, the application of the non-planar principle to marine propellers, dealt...... with in this paper, has led to the KAPPEL propeller with blades curved towards the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental and practical approach to develop and design marine propellers with non-planar lifting surfaces has resulted in propellers...

  13. Danish strategy for developing SOFC fuel cells 2010-2020; Dansk strategi for udvikling af SOFC-braendselsceller 2010-2020

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.; Linderoth, S. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Themsen, J. (Dantherm Power A/S, Hobro (Denmark)); Richter, A.B.; Hansen, Hakon J.; Holm-Larsen, H.; Andersen, Claus V. (Topsoe Fuel Cell A/S, Lyngby (Denmark))

    2010-09-15

    SOFC fuel cells are a promising technology for efficient production of electricity. The technology is expected to contribute very significantly to climate and environmental goals, security of supply of energy, increased employment and exports. Denmark has a very strong technology position within the SOFC area based on years of cooperation between Topsoe Fuel Cell and Risoe DTU as well as a later developed relationship with Dantherm Power. The Danish players have received more than DKK 250 million in public funding. With this support and the players' own funding (approx. two times higher than public support), the players managed over the past 10 years to bring development of SOFC technology significantly closer to the market. This strategy has been prepared by the Danish players in the field and gives a picture of the required overall development needs in the coming years. Technology development has reached the stage where in the coming years demonstrations on a larger scale have to be launched. The focus is basically on three valuable market segments: micro power and heat, auxiliary power for mobile applications, and decentralized power and CHP, which all have a great potential for market penetration internationally. When the market is established in one or more of these segments, other business opportunities must be explored for other applications based on the established technological platform. The road to commercialization is a long process that begins with demonstrations and later introduction of commercial products. The primary actors are currently the largest companies and institutions but as the number of produced fuel cell units increases, job creation with subcontractors and other directly related businesses and research centres will increase. A conservative estimate of market size worldwide is 2-4 GW of installed capacity per. year representing an annual turnover of 15-30 billion DKK and 10.000-20.000 more jobs. The export ratio is expected to exceed

  14. Impedance of SOFC electrodes: A review and a comprehensive case study on the impedance of LSM:YSZ cathodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Hjelm, Johan

    2014-01-01

    It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore, it was illustr......It was shown through a comprehensive impedance spectroscopy study that the impedance of the classic composite LSM:YSZ (lanthanum strontium manganite and yttria stabilized zirconia) solid oxide fuel cell (SOFC) cathode can be described well with porous electrode theory. Furthermore......, it was illustrated through a literature review on SOFC electrodes that porous electrode theory not only describes the classic LSM:YSZ SOFC cathode well, but SOFC electrodes in general. The extensive impedance spectroscopy study of LSM:YSZ cathodes consisted of measurements on cathodes with three different sintering...... temperatures and hence different microstructures and varying degrees of LSM/YSZ solid state interactions. LSM based composite cathodes, where YSZ was replaced with CGO was also studied in order to acquire further knowledge on the chemical compatibility between LSM and YSZ. All impedance measurements were...

  15. The ATLAS Planar Pixel Sensor R and D project

    International Nuclear Information System (INIS)

    Beimforde, M.

    2011-01-01

    Within the R and D project on Planar Pixel Sensor Technology for the ATLAS inner detector upgrade, the use of planar pixel sensors for highest fluences as well as large area silicon detectors is investigated. The main research goals are optimizing the signal size after irradiations, reducing the inactive sensor edges, adjusting the readout electronics to the radiation induced decrease of the signal sizes, and reducing the production costs. Planar n-in-p sensors have been irradiated with neutrons and protons up to fluences of 2x10 16 n eq /cm 2 and 1x10 16 n eq /cm 2 , respectively, to study the collected charge as a function of the irradiation dose received. Furthermore comparisons of irradiated standard 300μm and thin 140μm sensors will be presented showing an increase of signal sizes after irradiation in thin sensors. Tuning studies of the present ATLAS front end electronics show possibilities to decrease the discriminator threshold of the present FE-I3 read out chips to less than 1500 electrons. In the present pixel detector upgrade scenarios a flat stave design for the innermost layers requires reduced inactive areas at the sensor edges to ensure low geometric inefficiencies. Investigations towards achieving slim edges presented here show possibilities to reduce the width of the inactive area to less than 500μm. Furthermore, a brief overview of present simulation activities within the Planar Pixel R and D project is given.

  16. Synthesis of modified calcium aluminate with lanthanum manganite (LSM) for possible use in solid oxide fuel cell (SOFC); Sintese de aluminato de calcio modificado com manganita de lantanio (LSM) para possivel utilizacao em celula combustivel de oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de, E-mail: faili.cintia@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Escola de Engenharia. Departamento de Materiais; Cava, S.S. [Universidade Federal de Pelotas, RS (Brazil)

    2016-07-01

    The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)

  17. Geodesic distance in planar graphs

    International Nuclear Information System (INIS)

    Bouttier, J.; Di Francesco, P.; Guitter, E.

    2003-01-01

    We derive the exact generating function for planar maps (genus zero fatgraphs) with vertices of arbitrary even valence and with two marked points at a fixed geodesic distance. This is done in a purely combinatorial way based on a bijection with decorated trees, leading to a recursion relation on the geodesic distance. The latter is solved exactly in terms of discrete soliton-like expressions, suggesting an underlying integrable structure. We extract from this solution the fractal dimensions at the various (multi)-critical points, as well as the precise scaling forms of the continuum two-point functions and the probability distributions for the geodesic distance in (multi)-critical random surfaces. The two-point functions are shown to obey differential equations involving the residues of the KdV hierarchy

  18. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

    2010-01-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

  19. Attractive planar panelization using dynamic relaxation principles

    NARCIS (Netherlands)

    Gauss, Florian; Teuffel, Patrick

    2015-01-01

    In the presented paper a new method is proposed to approximate a given NURBS surface with a PQ (Planar Quad) mesh. The desired mesh layout will be generated in then attracted to the target surface. The process iteratively pulls the mesh vertices towards the target surface and then planarizes the

  20. Orientifold Planar Equivalence: The Chiral Condensate

    DEFF Research Database (Denmark)

    Armoni, Adi; Lucini, Biagio; Patella, Agostino

    2008-01-01

    The recently introduced orientifold planar equivalence is a promising tool for solving non-perturbative problems in QCD. One of the predictions of orientifold planar equivalence is that the chiral condensates of a theory with $N_f$ flavours of Dirac fermions in the symmetric (or antisymmetric...

  1. Planar Algebra of the Subgroup-Subfactor

    Indian Academy of Sciences (India)

    The crucial step in this identification is an exhibition of a model for the basic construction tower, and thereafter of the standard invariant of R ⋊ H ⊂ R ⋊ G in terms of operator matrices. We also obtain an identification between the planar algebra of the fixed algebra subfactor R G ⊂ R H and the -invariant planar subalgebra ...

  2. Piecewise planar Möbius bands

    DEFF Research Database (Denmark)

    Gravesen, Jens

    2005-01-01

    t is shown that a closed polygon with an odd number of vertices is the median of exactly one piecewise planar cylinder and one piecewise planar Möbius band, intersecting each other orthogonally. A closed polygon with an even number of vertices is in the generic case neither the median...

  3. SOFC solid oxide fuel cell power plants for the decentralised electric energy supply; SOFC-Brennstoffzellen-Kraftwerke fuer die dezentrale elektrische Energieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Fogang Tchonla, Etienne

    2012-07-01

    To use the fuel cell economically, the efficiency of the system must still be raised so that it can be set up in the market. Within the scope of analysis on this topic, a 120-kW-SOFC-demonstration power plant was to be considered. Since not enough information about the demonstration power plant from the operator was available for the investigation, we had to calculate with the help of the known technical data of similar power plants. After that a model was build and simulated by means of MATLAB/Simulink. Before that the single power plant components were being described. Two of them (the boost converter as well as the inverter) were looked at more thoroughly. As a result of the analysis, it was found that a standard inverter which had been conceived for other applications, for example, Photovoltaic or Wind Power can also be used for fuel cells. Unfortunately, this was not the case for the added boost converter. It had to be precisely conceived for the used fuel cell type. After this discovery information was won for the realization of a 1-MW-Fuel Cell Power Plant. The topology of the 1-MW-power plant was fixed on the basis of the 120-kW-system. A parallel connection of eight 120-kW SOFC-fuel cell aggregates is intended, as well as a connection at the outlet side 120-kW boost converters. A standard inverter with 1 MW electrical power as well as a 1-MVA-transformer could be used for the realization of the 1-MW-power plant. The binding of the power plant in the three-phase current network was examined in view of the norms, laws and connection conditions. Beside the distinction of the operating forms of the power plant (parallel or isolated operation) the security of the plant was emphasized with regard to quick fault recognition, safe supply line isolation in the fault case as well as a compliance of the prescribed regulations. To verify the calculated results as well as the provided models, a 10-kW-labor sample was built and examined in the lab. This experimental

  4. The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-24

    This report documents the implementation of several related 1D heat flow problems in the verification package ExactPack [1]. In particular, the planar sandwich class defined in Ref. [2], as well as the classes PlanarSandwichHot, PlanarSandwichHalf, and other generalizations of the planar sandwich problem, are defined and documented here. A rather general treatment of 1D heat flow is presented, whose main results have been implemented in the class Rod1D. All planar sandwich classes are derived from the parent class Rod1D.

  5. Planar Bragg Grating Sensors—Fabrication and Applications: A Review

    Directory of Open Access Journals (Sweden)

    I. J. G. Sparrow

    2009-01-01

    Full Text Available We discuss the background and technology of planar Bragg grating sensors, reviewing their development and describing the latest developments. The physical operating principles are discussed, relating device operation to user requirements. Recent performance of such devices includes a planar Bragg grating sensor design which allows refractive index resolution of 1.9×10−6 RIU and temperature resolution of 0.03∘C. This sensor design is incorporated into industrialised applications allowing the sensor to be used for real time sensing in intrinsically safe, high-pressure pipelines, or for insertion probe applications such as fermentation. Initial data demonstrating the ability to identify solvents and monitor long term industrial processes is presented. A brief review of the technology used to fabricate the sensors is given along with examples of the flexibility afforded by the technique.

  6. An Electronically Controlled 8-Element Switched Beam Planar Array

    KAUST Repository

    Sharawi, Mohammad S.

    2015-02-24

    An 8-element planar antenna array with electronically controlled switchable-beam pattern is proposed. The planar antenna array consists of patch elements and operates in the 2.45 GHz ISM band. The array is integrated with a digitally controlled feed network that provides the required phases to generate 8 fixed beams covering most of the upper hemisphere of the array. Unlike typical switchable beam antenna arrays, which operate only in one plane, the proposed design is the first to provide full 3D switchable beams with simple control. Only a 3-bit digital word is required for the generation of the 8 different beams. The integrated array is designed on a 3-layer PCB on a Taconic substrate (RF60A). The total dimensions of the fabricated array are 187.1 × 261.3 × 1.3mm3.

  7. Resonance transparency with low-loss in toroidal planar metamaterial

    Science.gov (United States)

    Xiang, Tianyu; Lei, Tao; Hu, Sen; Chen, Jiao; Huang, Xiaojun; Yang, Helin

    2018-03-01

    A compact planar construction composed of asymmetric split ring resonators was designed with a low-loss, high Q-factor resonance transparency at microwave frequency. The singularity property of the proposed metamaterial owing to the enhanced toroidal dipole T is demonstrated via numerical and experimental methods. The transmission peak can reach up to 0.91 and the loss is perfectly repressed, which can be testified by radiated power, H-field distributions, and the imaginary parts of effective permittivity and permeability. The designed planar metamaterial may have numerous potential applications at microwave, terahertz, and optical frequency, e.g., for ultrasensitive sensing, slow-light devices, lasing spacers, even invisible information transfer.

  8. Variability in DMSA reporting following urinary tract infection in children: pinhole, planar, and pinhole with planar

    International Nuclear Information System (INIS)

    Rossleigh, M.A.; Christian, C.L.; Craig, J.C.; Howman-Giles, R.B.; Grunewald, S.

    2004-01-01

    Purpose: To determine whether the provision of DMSA images obtained by pinhole collimation reduces inter-observer variability of reporting compared with planar DMSA images alone. Methods: One hundred consecutive DMSA images were independently interpreted three times (pinhole alone, planar alone, pinhole and planar) by four participating nuclear medicine specialists from different departments and in random order. The presence or absence of renal parenchymal abnormality was classified using the modified four level grading system of Goldraich with mean values for the 6 comparisons reported. Results: The proportion of DMSA images interpreted as abnormal was 31% for planar, 34% for pinhole and 33% for planar with pinhole. Agreement was 89% for planar alone, 89% for pinhole alone and 90% for planar with pinhole, with kappa values 0.74, 0.75 and 0.80 respectively for the normal-abnormal scan classification of individual children. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. Reasons for disagreement in reporting included different interpretations of 'abnormalities' as normal anatomical variations (splenic impression, fetal lobulation, duplex collecting systems, column of Bertin) or true parenchymal abnormalities, different adjustments in thresholds for reporting abnormality when images were technically suboptimal, different weighting given to pinhole and planar images when both were provided, and error. Conclusion: Four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone, pinhole alone and planar with pinhole DMSA images, but the provision of both sets of images, planar and pinhole, did not reduce variability. (authors)

  9. Fracture-mechanical analysis of metal/ceramic composites for applications in high-temperature fuel cells (SOFC); Bruchmechanische Untersuchung von Metall/Keramik-Verbunsystemen fuer die Anwendung in der Hochtemperaturbrennstoffzelle (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Bernd Josef

    2008-08-25

    The author investigated the deformation and damage behaviour of soldered ceramic/metal joints in SOFC stacks, using thermochemical methods. Methods for analyzing sandwich systems and for mechanical characterization of joints were adapted and modified in order to provide fundamental understanding of the mechanical properties of soldered joints. [German] In dieser Arbeit wurde das Verformungs- und Schaedigungsverhalten von Keramik/ Metall-Loetverbindungen fuer SOFC-Stacks thermomechanisch untersucht. Verfahren zur Analyse von Schichtsystemen und fuer die mechanische Charakterisierung von Fuegeverbindungen wurden adaptiert und weiterentwickelt, um zu einem grundlegenden Verstaendnis der mechanischen Eigenschaften von Loetverbindungen zu gelangen.

  10. Synthesis of modified calcium aluminate with lanthanum manganite (LSM) for possible use in solid oxide fuel cell (SOFC)

    International Nuclear Information System (INIS)

    Veiga, F.C.T.; Jurado, J.; Sousa, V.C. de

    2016-01-01

    The fuel cells solid oxide (SOFC) is made up of three basic elements: two electrodes, the anode and cathode and a conductive electrolyte ions. The objective of this work consists of calcium aluminate synthesis modified LSM in a 1: 1 by combustion synthesis method with a view to its use as a cathode in SOFC. The characterization of the post was carried out by the methods of XRD, TEM and EIS. After heat treatment at 1200°C/4 hours it was possible to obtain Ca0.5Sr1.5MnO4 and CaMnO2.56 phases. The material showed a semiconductor characteristics because with increasing temperature the electrical resistance value tends to decrease obtaining electrical conductivity greater than 10-6S / cm featuring an extrinsic semiconductor with an activation energy of 0.12. Therefore, with an activation energy value within the range of materials used for a SOFC cathodes. (author)

  11. Direct Utilization of Liquid Fuels in SOFC for Portable Applications: Challenges for the Selection of Alternative Anodes

    Directory of Open Access Journals (Sweden)

    Massimiliano Cimenti

    2009-06-01

    Full Text Available Solid oxide fuel cells (SOFC have the advantage of being able to operate with fuels other than hydrogen. In particular, liquid fuels are especially attractive for powering portable applications such as small power generators or auxiliary power units, in which case the direct utilization of the fuel would be convenient. Although liquid fuels are easier to handle and transport than hydrogen, their direct use in SOFC can lead to anode deactivation due to carbon formation, especially on traditional nickel/yttria stabilized zirconia (Ni/YSZ anodes. Significant advances have been made in anodic materials that are resistant to carbon formation but often these materials are less electrochemically active than Ni/YSZ. In this review the challenges of using liquid fuels directly in SOFC, in terms of gas-phase and catalytic reactions within the anode chamber, will be discussed and the alternative anode materials so far investigated will be compared.

  12. Optical sensor in planar configuration based on multimode interference

    Science.gov (United States)

    Blahut, Marek

    2017-08-01

    In the paper a numerical analysis of optical sensors based on multimode interference in planar one-dimensional step-index configuration is presented. The structure consists in single-mode input and output waveguides and multimode waveguide which guide only few modes. Material parameters discussed refer to a SU8 polymer waveguide on SiO2 substrate. The optical system described will be designed to the analysis of biological substances.

  13. Fabrication of Sr- and Co-doped lanthanum chromite interconnectors for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Setz, L.F.G. [Departamento de Engenharia de Materiais, Universidade Federal de Sao Carlos - DEMa/UFSCar (Brazil); Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN (Brazil); Santacruz, I. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, 29071 Malaga (Spain); Colomer, M.T., E-mail: tcolomer@icv.csic.es [Instituto de Ceramica y Vidrio, ICV (CSIC), 28049 Madrid (Spain); Mello-Castanho, S.R.H. [Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN (Brazil); Moreno, R. [Instituto de Ceramica y Vidrio, ICV (CSIC), 28049 Madrid (Spain)

    2011-07-15

    Graphical abstract: FESEM micrographs of the fresh fracture surfaces for the La{sub 0.80}Sr{sub 0.20}Cr{sub 0.92}Co{sub 0.08}O{sub 3} sintered specimens cast from optimised suspensions with 13.5, 15 and 17.5 vol.% solids loading. Aqueous suspensions were prepared using ammonium polyacrylate (PAA) as dispersant and tetramethylammonium hydroxide (TMAH) to assure a basic pH and providing stabilization. Sintering of the green discs was performed in air at 1600 {sup o}C for 4 h. Highlights: {yields} Optimum casting slips were achieved with 3 wt.% of ammonium polyacrylate and 1 wt.% of tetramethylammonium hydroxide. -- Abstract: Many studies have been performed dealing with the processing conditions of electrodes and electrolytes in solid oxide fuel cells (SOFCs). However, the processing of the interconnector material has received less attention. Lanthanum chromite (LaCrO{sub 3}) is probably the most studied material as SOFCs interconnector. This paper deals with the rheology and casting behaviour of lanthanum chromite based materials to produce interconnectors for SOFCs. A powder with the composition La{sub 0.80}Sr{sub 0.20}Cr{sub 0.92}Co{sub 0.08}O{sub 3} was obtained by combustion synthesis. Aqueous suspensions were prepared to solids loading ranging from 8 to 17.5 vol.%, using ammonium polyacrylate (PAA) as dispersant and tetramethylammonium hydroxide (TMAH) to assure a basic pH and providing stabilization. The influence of the additives concentrations and suspension ball milling time were studied. Suspensions prepared with 24 h ball milling, with 3 wt.% and 1 wt.% of PAA and TMAH, respectively, yielded the best conditions for successful slip casting. Sintering of the green discs was performed in air at 1600 {sup o}C for 4 h leading to relatively dense materials.

  14. Effect of ionic conductivity of zirconia electrolytes on polarization properties of various electrodes in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masahiro; Uchida, Hiroyuki; Yoshida, Manabu [Yamanashi Univ., Kofu (Japan)

    1996-12-31

    Solid oxide fuel cells (SOFCs) have been intensively investigated because, in principle, their energy conversion efficiency is fairly high. Lowering the operating temperature of SOFCs from 1000{degrees}C to around 800{degrees}C is desirable for reducing serious problems such as physical and chemical degradation of the constructing materials. The object of a series of the studies is to find a clue for achieving higher electrode performances at a low operating temperature than those of the present level. Although the polarization loss at electrodes can be reduced by using mixed-conducting ceria electrolytes, or introducing the mixed-conducting (reduced zirconia or ceria) laver on the conventional zirconia electrolyte surface, no reports are available on the effect of such an ionic conductivity of electrolytes on electrode polarizations. High ionic conductivity of the electrolyte, of course, reduces the ohmic loss. However, we have found that the IR-free polarization of a platinum anode attached to zirconia electrolytes is greatly influenced by the ionic conductivity, {sigma}{sub ion}, of the electrolytes used. The higher the {sigma}{sub ion}, the higher the exchange current density, j{sub 0}, for the Pt anode in H{sub 2} at 800 {approximately} 1000{degrees}C. It was indicated that the H{sub 2} oxidation reaction rate was controlled by the supply rate of oxide ions through the Pt/zirconia interface which is proportional to the {sigma}{sub ion}. Recently, we have proposed a new concept of the catalyzed-reaction layers which realizes both high-performances of anodes and cathodes for medium-temperature operating SOFCs. We present the interesting dependence of the polarization properties of various electrodes (the SDC anodes with and without Ru microcatalysts, Pt cathode, La(Sr)MnO{sub 3} cathodes with and without Pt microcatalysts) on the {sigma}{sub ion} of various zirconia electrolytes at 800 {approximately} 1000{degrees}C.

  15. Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo, E-mail: mcarmov@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Grupo de Estudos em Cinetica e Catalise; Ballarini, Adriana; Maina, Silvia [Instituto de Investigaciones en Catalisis Y Petroquimica Ing. Jose Miguel Parera (INCAPE), Santa Fe (Argentina)

    2017-01-15

    The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

  16. Evaluation of nickel and copper catalysts in biogas reforming for hydrogen production in SOFC

    International Nuclear Information System (INIS)

    Silva, Leonardo Alves; Martins, Andre Rosa; Rangel, Maria do Carmo

    2017-01-01

    The solid oxide fuel cells (SOFC) enable the efficient generation of clean energy, fitting the current requirements of the growing demand for electricity and for the environment preservation. When powered with biogas (from digesters of municipal wastes), the SOFCs also contribute to reduce the environmental impact of these wastes. The most suitable route to produce hydrogen inside SOFC from biogas is through dry reforming but the catalyst is easily deactivated by coke, because of the high amounts of carbon in the stream. A promising way to overcome this drawback is by adding a second metal to nickel-based catalysts. Aiming to obtain active, selective and stable catalysts for biogas dry reforming, solids based on nickel (15%) and copper (5%) supported on aluminum and magnesium oxide were studied in this work. Samples were prepared by impregnating the support with nickel and copper nitrate, followed by calcination at 500, 600 and 800 deg C. It was noted that all solids were made of nickel oxide, nickel aluminate and magnesium aluminate but no copper compound was found. The specific surface areas did not changed with calcination temperature but the nickel oxide average particles size increased. The solids reducibility decreased with increasing temperature. All catalysts were active in methane dry reforming, leading to similar conversions but different selectivities to hydrogen and different activities in water gas shift reaction (WGSR). This behavior was assigned to different interactions between nickel and copper, at different calcination temperatures. All catalysts were active in WGSR, decreasing the hydrogen to carbon monoxide molar ratio and producing water. The catalyst calcined at 500 deg C was the most promising one, leading to the highest hydrogen yield, besides the advantage of being produced at the lowest calcination temperature, requiring less energy in its preparation. (author)

  17. Shape distortion and thermo-mechanical properties of SOFC components from green tape to sintering body

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Ni, De Wei; Tadesse Molla, Tesfaye

    due to binder burn out, differential shrinkage behavior and to a potential interfacial reaction between the two materials. To analyze the phenomena, shrinkage of SOFC components single layers and bilayered samples were measured insitu by optical dilatometer. The densification mismatch stress, due...... to the strain rate difference between materials, was calculated using Cai’s model. Camber (curvature) development for in situ co-firing of a bi-layer ceramic green tape has been investigated. Analysis of shape evolution from green to sintered body can be carried out by the thermo-mechanical analysis techniques....

  18. Thermoeconomic Analysis Of a Gasification Plant Fed By Woodchips And Integrated With SOFC And STIG Cycles

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rokni, Masoud

    2013-01-01

    of the influence of SOFC stack cost on the generation cost is also presented. In order to discuss the investment cost, an economic analysis has been carried out by involving main parameters such as Net Present Value (NPV), Internal Rate of Return (IRR), Time of Return of Investment (TIR) are calculated...... above 53% and 43% respectively which are significantly greater than conventional 10 MWe plants fed by biomass. Thermo-economic analysis provides an average cost of electricity for best performing layouts close to 6.4 and 9.4 c€/kWe which is competitive within the market. A sensitivity analysis...

  19. The mechanism behind redox instability of anodes in high-temperature SOFCs

    DEFF Research Database (Denmark)

    Klemensø, Trine; Chung, Charissa; Larsen, Peter Halvor

    2005-01-01

    Bulk expansion of the anode upon oxidation is considered to be responsible for the lack of redox stability in high-temperature solid oxide fuel cells (SOFCs). The bulk expansion of nickel-yttria stabilized zirconia (YSZ) anode materials was measured by dilatometry as a function of sample geometry......, ceramic component, temperature, and temperature cycling. The strength of the ceramic network and the degree of Ni redistribution appeared to be key parameters of the redox behavior. A model of the redox mechanism in nickel-YSZ anodes was developed based on the dilatometry data and macro...

  20. Reversibility of the SOFC for the hydrogen production by high temperature electrolysis

    International Nuclear Information System (INIS)

    Brisse, A.; Marrony, M.; Perednis, D.; Schefold, J.; Jose-Garcia, M.; Zahid, M.

    2007-01-01

    The behaviour of two SOFC cells in electrolysis mode is studied. The performances of these solid oxide cells, reversible at 800 C and for current densities between 0 and -0.42 A/cm 2 , are presented. A weaker polarisation resistance has been measured for the cell containing a mixed conductor as oxygen electrode. For each cell, a limitation by gaseous diffusion has been observed under current. This phenomenon appears for current densities which are higher for the mixed conductor cell as oxygen electrode. (O.M.)

  1. Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kWe have been performed. Woodchips are used as gasification feedstock to produce syngas......Wh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214$/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity...

  2. NiO/YSZ Reduction for SOFC/SOEC Studied In Situ by Environmental Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Agersted, Karsten; Hansen, Karin Vels

    2014-01-01

    SOFCs/SOECs are typically composed of ceramic materials, which are highly complex at the nano-scale. Scanning and transmission electron microscopy (SEM and TEM) are routinely applied for studying these nano-scaled structures post mortem, but only few SOFC/SOEC studies have applied environmental T...... and constant temperature ramping rate of 1°C/min. The NiO observed in the first image at 320°C is dense. From the lower left corner a front of porous Ni is progressing until full reduction at 340°C. [Formula]...

  3. Electrochemical performances of proton-conducting SOFC with La-Sr-Fe-O cathode fabricated by electrophoretic deposition techniques

    International Nuclear Information System (INIS)

    Asamoto, Makiko; Miyake, Shinji; Yonei, Yuka; Yamaura, Hiroyuki; Yahiro, Hidenori

    2009-01-01

    The electrochemical performances of Proton-conducting SOFC with La 0.7 Sr 0.3 FeO 3 (LSF) cathode fabricated by the electrophoretic deposition (EPD) technique were investigated. The EPD technique provided the uniform layer of LSF cathode with constant thickness and can easily control the thickness by changing an applied voltage. The power density of the SOFC cell was dependent on the thickness of LSF cathode. The activation energy was measured to elucidate the rate-determining step for LSF cathode reaction. (author)

  4. Review of manufacturing processes for fabrication of SOFC components

    International Nuclear Information System (INIS)

    Stacey, B.; Badwal, S.P.S.; Foger, K.

    1998-01-01

    In order for fuel cell technology to be commercial, it must meet stringent criteria of reliability, life-time expectations and cost. While materials play an important role in determining these parameters, engineering design and manufacturing processes for fuel cell stack components are equally important. Manufacturing processes must be low cost and suitable for large volume production for the technology to be viable and competitive in the market place. Several processes suitable for the production of ceramic components used in solid oxide fuel cells as well as ceramic coating techniques required for the protection of some metal components have been described. Copyright (1998) Australasian Ceramic Society

  5. Sealing of ceramic SOFC-components with glass seals; Fuegen von keramischen Komponenten der Hochtemperatur-Brennstoffzellen mittels Glas- und Glaskeramikloten

    Energy Technology Data Exchange (ETDEWEB)

    Schillig, Cora

    2012-07-10

    The solid oxide fuel cell (SOFC) converts chemical energy of a fuel directly into electrical energy. However, for the implementation of SOFC-technology in competition to conventional power plants costs have to be reduced. The use of an alternative tubular cell design without closed end would allow reducing costs during cell manufacturing. However, this change in design makes a gastight sealing inside the generator near the gas inlet necessary. Different ceramic materials with varying coefficients of thermal expansion have to be sealed gastight and electrical insulating at temperatures between 850 C and 1000 C to prevent the gases from mixing and an electrical shortcut between the cells. This work comprises analysis of commercially available glass and glass-ceramic systems manufactured by Schott Electronic Packaging, Areva T and D and Ferro Corporation. Additionally new developed sealing glass and glass-ceramic systems were investigated and all systems were characterized fundamentally for the use as sealing material in SOFC generators. Therefore different test assemblies and series were conducted. Essential characteristics of a suitable sealing system are a thermal expansion coefficient between 9,5 and 12 . 10{sup -6}K{sup -1}, a viscosity in the range between 10{sup 4} to 10{sup 6} dPa{sup *}s and a wetting angle smaller than 90 during the sealing process. Also unwanted chemical side reactions between the sealing partners must be prevented, because a change in the phase composition or the creation of new phases in the sealing material could endanger the stability of the seal. Heat cycles, particularly those during generator operation, cause deterioration of the sealing material and subsequent reduction in its ability to prevent mixing of the gases. Sealant leaks can drastically impact efficiency of the generator. In order to ensure optimum operation low leak rates around 2,3 . 10{sup -4} mbar l/sec/cm{sup 2} must be maintained. Especially glass and glass

  6. Planar impact experiments for EOS measurements

    International Nuclear Information System (INIS)

    Furnish, M.D.

    1993-01-01

    The community concerned with the numerical modeling of groundshock produced by underground nuclear tests must have access to materials data to benchmark models of rock behavior. Historically the primary source of these data has been planar impact experiments. These experiments have involved gun, explosive and electrical launchers. Other methods of introducing planar shocks include shock driving by in-contact explosives or laser bursts. This paper briefly describes gun launcher-based planar impact methods used to characterize geological materials at Sandia National Laboratories

  7. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  8. Comparison Of Planar And Wound Transformers For Flyback Forward And Half-Bridge Space Power Converters

    Science.gov (United States)

    Bjorklund, Thomas; Andreasen, John; Brosen, Finn; Matthiesen, Erik; Poulsen, Ole

    2011-10-01

    Planar technology has now entered the space domain. The big advantages of planar technology are; - Low profile - Excellent repeatability - Economical assembly - Mechanical integrity - Superior thermal characteristics This is why the general power industries increasingly are using planar magnetics in more and more applications, and therefore also why we see a rising demand for the usability of the planar technology among space application developers. The differences between wound and planar transformers have been mapped with a detailed look on the various parasitic component values, such as DC- and AC- resistance, Leakage Inductance and stray capacitance, and revealed the magnitude of the advantages of planar technology. This technical solution is proven in prototypes that have been built in different combination of PCB's and copper foil, with more or less interleaving of windings. Furthermore the transformers have been designed with several outputs stacked together with a fairly high number of primary turns, in order to have planar transformers similar to the wound types that are generally used for space applications.

  9. Dynamic Planar Range Maxima Queries

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Tsakalidis, Konstantinos

    2011-01-01

    We consider the dynamic two-dimensional maxima query problem. Let P be a set of n points in the plane. A point is maximal if it is not dominated by any other point in P. We describe two data structures that support the reporting of the t maximal points that dominate a given query point, and allow...... for insertions and deletions of points in P. In the pointer machine model we present a linear space data structure with O(logn + t) worst case query time and O(logn) worst case update time. This is the first dynamic data structure for the planar maxima dominance query problem that achieves these bounds...... are integers in the range U = {0, …,2 w  − 1 }. We present a linear space data structure that supports 3-sided range maxima queries in O(logn/loglogn+t) worst case time and updates in O(logn/loglogn) worst case time. These are the first sublogarithmic worst case bounds for all operations in the RAM model....

  10. Carbon Tolerant Fuel Electrodes for Reversible Sofc Operating on Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Papazisi Kalliopi Maria

    2017-01-01

    Full Text Available A challenging barrier for the broad, successful implementation of Reversible Solid Oxide Fuel Cell (RSOFC technology for Mars application utilizing CO2 from the Martian atmosphere as primary reactant, remains the long term stability by the effective control and minimization of degradation resulting from carbon built up. The perovskitic type oxide material La0.75Sr0.25Cr0.9Fe0.1O3-δ (LSCF has been developed and studied for its performance and tolerance to carbon deposition, employed as bi-functional fuel electrode in a Reversible SOFC operating on the CO2 cycle (Solid Oxide Electrolysis Cell/SOEC: CO2 electrolysis, Solid Oxide Fuel Cell/SOFC: power generation through the electrochemical reaction of CO and oxygen. A commercial state-of-the-art NiO-YSZ (8% mol Y2O3 stabilized ZrO2 cermet was used as reference material. CO2 electrolysis and fuel cell operation in 70% CO/CO2 were studied in the temperature range of 900-1000°C. YSZ was used as electrolyte while LSM-YSZ/LSM (La0.2Sr0.8MnO3 as oxygen electrode. Results showed that LSCF had high and stable performance under RSOFC operation.

  11. Thermodynamic simulation of biomass gas steam reforming for a solid oxide fuel cell (SOFC system

    Directory of Open Access Journals (Sweden)

    A. Sordi

    2009-12-01

    Full Text Available This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC, as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.

  12. Comparative LCA of methanol-fuelled SOFCs as auxiliary power systems on-board ships

    International Nuclear Information System (INIS)

    Strazza, C.; Del Borghi, A.; Costamagna, P.; Traverso, A.; Santin, M.

    2010-01-01

    Fuel cells own the potential for significant environmental improvements both in terms of air quality and climate protection. Through the use of renewable primary energies, local pollutant and greenhouse gas emissions can be significantly minimized over the full life cycle of the electricity generation process, so that marine industry accounts renewable energy as its future energy source. The aim of this paper is to evaluate the use of methanol in Solid Oxide Fuel Cells (SOFC), as auxiliary power systems for commercial vessels, through Life Cycle Assessment (LCA). The LCA methodology allows the assessment of the potential environmental impact along the whole life cycle of the process. The unit considered is a 20 kWel fuel cell system. In a first part of the study different fuel options have been compared (methanol, bio-methanol, natural gas, hydrogen from cracking, electrolysis and reforming), then the operation of the cell fed with methanol has been compared with the traditional auxiliary power system, i.e. a diesel engine. The environmental benefits of the use of fuel cells have been assessed considering different impact categories. The results of the analysis show that fuel production phase has a strong influence on the life cycle impacts and highlight that feeding with bio-methanol represents a highly attractive solution from a life cycle point of view. The comparison with the conventional auxiliary power system shows extremely lower impacts for SOFCs.

  13. Evaluation of STS 430 and STS 444 for SOFC Interconnect Applications

    International Nuclear Information System (INIS)

    Kim, S. H.; Huh, J. Y.; Jun, J. H.; Kim, D. H.; Jun, J. H.

    2007-01-01

    Ferritic stainless steels for the SOFC interconnect applications are required to possess not only a good oxidation resistance, but also a high electrical conductivity of te oxide scale that forms during exposure at the SOFC operating environment. In order to understand the effects of alloying elements on the oxidation behavior of ferritic stainless steels and on the electrical properties of oxide scales, two kinds of commercial ferritic stainless steels, STS 430 and STS 444, were investigated by performing isothermal oxidations at 800 .deg. C in a wet air containing 3% H 2 O. The results showed that STS 444 was superior to STS 430 in both of the oxidation resistance and the area specific resistance. Although STS 444 contained a less amount of Mn for the (Mn, Cr) 3 O 4 spinel formation than STS 430, the minor alloying elements of Al and Mo in STS 444, which were accumulated in the base metal region adjacent the scale, were suggested to reduce the scale growth rate and to enhance the scale adherence to the base metal

  14. Palliative effects of H2 on SOFCs operating with carbon containing fuels

    Science.gov (United States)

    Reeping, Kyle W.; Bohn, Jessie M.; Walker, Robert A.

    2017-12-01

    Chlorine can accelerate degradation of solid oxide fuel cell (SOFC) Ni-based anodes operating on carbon containing fuels through several different mechanisms. However, supplementing the fuel with a small percentage of excess molecular hydrogen effectively masks the degradation to the catalytic activity of the Ni and carbon fuel cracking reaction reactions. Experiments described in this work explore the chemistry behind the "palliative" effect of hydrogen on SOFCs operating with chlorine-contaminated, carbon-containing fuels using a suite of independent, complementary techniques. Operando Raman spectroscopy is used to monitor carbon accumulation and, by inference, Ni catalytic activity while electrochemical techniques including electrochemical impedance spectroscopy and voltammetry are used to monitor overall cell performance. Briefly, hydrogen not only completely hides degradation observed with chlorine-contaminated carbon-containing fuels, but also actively removes adsorbed chlorine from the surface of the Ni, allowing for the methane cracking reaction to continue, albeit at a slower rate. When hydrogen is removed from the fuel stream the cell fails immediately due to chlorine occupation of methane/biogas reaction sites.

  15. FEEDSTOCK-FLEXIBLE REFORMER SYSTEM (FFRS) FOR SOLID OXIDE FUEL CELL (SOFC)- QUALITY SYNGAS

    Energy Technology Data Exchange (ETDEWEB)

    Jezierski, Kelly; Tadd, Andrew; Schwank, Johannes; Kibler, Roland; McLean, David; Samineni, Mahesh; Smith, Ryan; Parvathikar, Sameer; Mayne, Joe; Westrich, Tom; Mader, Jerry; Faubert, F. Michael

    2010-07-30

    The U.S. Department of Energy National Energy Technology Laboratory funded this research collaboration effort between NextEnergy and the University of Michigan, who successfully designed, built, and tested a reformer system, which produced highquality syngas for use in SOFC and other applications, and a novel reactor system, which allowed for facile illumination of photocatalysts. Carbon and raw biomass gasification, sulfur tolerance of non-Platinum Group Metals (PGM) based (Ni/CeZrO2) reforming catalysts, photocatalysis reactions based on TiO2, and mild pyrolysis of biomass in ionic liquids (ILs) were investigated at low and medium temperatures (primarily 450 to 850 C) in an attempt to retain some structural value of the starting biomass. Despite a wide range of processes and feedstock composition, a literature survey showed that, gasifier products had narrow variation in composition, a restriction used to develop operating schemes for syngas cleanup. Three distinct reaction conditions were investigated: equilibrium, autothermal reforming of hydrocarbons, and the addition of O2 and steam to match the final (C/H/O) composition. Initial results showed rapid and significant deactivation of Ni/CeZrO2 catalysts upon introduction of thiophene, but both stable and unstable performance in the presence of sulfur were obtained. The key linkage appeared to be the hydrodesulfurization activity of the Ni reforming catalysts. For feed stoichiometries where high H2 production was thermodynamically favored, stable, albeit lower, H2 and CO production were obtained; but lower thermodynamic H2 concentrations resulted in continued catalyst deactivation and eventual poisoning. High H2 levels resulted in thiophene converting to H2S and S surface desorption, leading to stable performance; low H2 levels resulted in unconverted S and loss in H2 and CO production, as well as loss in thiophene conversion. Bimetallic catalysts did not outperform Ni-only catalysts, and small Ni particles were

  16. PT-symmetric planar devices for field transformation and imaging

    International Nuclear Information System (INIS)

    Valagiannopoulos, C A; Monticone, F; Alù, A

    2016-01-01

    The powerful tools of transformation optics (TO) allow an effective distortion of a region of space by carefully engineering the material inhomogeneity and anisotropy, and have been successfully applied in recent years to control electromagnetic fields in many different scenarios, e.g., to realize invisibility cloaks and planar lenses. For various field transformations, it is not necessary to use volumetric inhomogeneous materials, and suitably designed ultrathin metasurfaces with tailored spatial or spectral responses may be able to realize similar functionalities within smaller footprints and more robust mechanisms. Here, inspired by the concept of metamaterial TO lenses, we discuss field transformations enabled by parity-time (PT) symmetric metasurfaces, which can emulate negative refraction. We first analyze a simple realization based on homogeneous and local metasurfaces to achieve negative refraction and imaging, and we then extend our results to arbitrary PT-symmetric two-port networks to realize aberration-free planar imaging. (paper)

  17. An Integrated Approach to Modeling and Mitigating SOFC Failure

    Energy Technology Data Exchange (ETDEWEB)

    Jianmin Qu; Andrei Fedorov; Comas Haynes

    2006-05-15

    The specific objectives of this project were: (1) To develop and demonstrate the feasibility of an integrated predictive computer-based tool for fuel cell design and reliability/durability analysis, (2) To generate new scientific and engineering knowledge to better enable SECA Industry Teams to develop reliable, low-cost solid-oxide fuel cell power generation systems, (3) To create technology breakthroughs to address technical risks and barriers that currently limit achievement of the SECA performance and cost goals for solidoxide fuel cell systems, and (4) To transfer new science and technology developed in the project to the SECA Industry Teams. Through this three-year project, the Georgia Tech's team has demonstrated the feasibility of the solution proposed and the merits of the scientific path of inquiry, and has developed the technology to a sufficient level such that it can be utilized by the SECA Industry Teams. This report summarizes the project's results and achievements.

  18. Two-dimensional simulation of gas concentration impedance for a planar solid oxide fuel cell

    International Nuclear Information System (INIS)

    Fadaei, M.; Mohammadi, R.; Ghassemi, M.

    2014-01-01

    Highlights: • The 2D simulation shows another feature in concentration impedance. • The channel gas transport causes a capacitive behavior. • Anode polarization variation has a significant influence on velocity distribution. • The influence of 2D simulation is important for channel height bigger than 2 mm. - Abstract: This paper presents a two-dimensional model for a planar solid oxide fuel cell (SOFC) anode in order to simulate the steady-state performance characteristics as well as the electrochemical impedance spectra. The developed model couples the mass transport with the electrochemical kinetics. The transient conservation equations (momentum and species equations) are solved numerically and the linear kinetic is used for the anode electrochemistry. In order to solve the system of the nonlinear equations, an in-house code based on the finite volume method is developed and utilized. A parametric study is also carried out and the results are discussed. Results show a capacitive semicircle in the Nyquist plot which is identical to the gas concentration impedance. The simulation results are in good agreement with published data

  19. Modified planar functions and their components

    DEFF Research Database (Denmark)

    Anbar Meidl, Nurdagül; Meidl, Wilfried Meidl

    2017-01-01

    functions in odd characteristic as a vectorial bent function. We finally point out that though these components behave somewhat different than the multivariate bent4 functions, they are bent or semibent functions shifted by a certain quadratic term, a property which they share with their multivariate......Zhou ([20]) introduced modified planar functions in order to describe (2n; 2n; 2n; 1) relative difference sets R as a graph of a function on the finite field F2n, and pointed out that projections of R are difference sets that can be described by negabent or bent4 functions, which are Boolean...... functions given in multivariate form. One of the objectives of this paper is to contribute to the understanding of these component functions of modified planar functions. Moreover, we obtain a description of modified planar functions by their components which is similar to that of the classical planar...

  20. Planar Elongation Measurements on Soft Elastomers

    DEFF Research Database (Denmark)

    Jensen, Mette Krog; Skov, Anne Ladegaard; Rasmussen, Henrik K.

    2009-01-01

    A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation.......A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation....

  1. Generators for finite depth subfactor planar algebras

    Indian Academy of Sciences (India)

    The main result of Kodiyalam and Tupurani [3] shows that a subfactor planar algebra of finite depth is singly generated with a finite presentation. If P is a subfactor planar algebra of depth k, it is shown there that a single 2k-box generates P. It is natural to ask what the smallest s is such that a single s-box generates P. While ...

  2. Planar half-cell shaped precursor body

    DEFF Research Database (Denmark)

    2015-01-01

    The invention relates to a half-cell shaped precursor body of either anode type or cathode type, the half-cell shaped precursor body being prepared to be free sintered to form a sintered or pre-sintered half-cell being adapted to be stacked in a solid oxide fuel cell stack. The obtained half......-cell has an improved planar shape, which remains planar also after a sintering process and during temperature fluctuations....

  3. Development of perovskite cathodes for solid oxide fuel cells (SOFC); Desenvolvimento de catodos de perovskitas para celula a combustivel solido de eletrolito solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica], e-mail: joelma@iq.unesp.br; Pereira, J.T.; Saeki, M.J. [UNESP, Bauru, SP (Brazil). Faculdade de Ciencias

    2006-07-01

    Solid Oxide Fuel Cells (SOFC) are energy conversion systems of great interest for industrial applications because they present a high efficiency for energy generation and several advantages for the environment. In this work, perovskite type oxides La{sub 085}Sr{sub 0,15}MnO{sub 3}, La{sub 0,7} Sr{sub 0,3}MnO{sub 3}, La{sub 0,6}Sr{sub 0,4}MnO{sub 3}, La{sub 0,85}Sr{sub 0,15}CoO{sub 3}, La{sub 0,7}Sr{sub 0,3}CoO{sub 3}, La{sub 0,6}Sr{sub 0,4}CoO{sub 3}, La{sub 0.6}Sr{sub 0,4}Fe{sub 0,8}Co{sub 0,2}O{sub 3} e La{sub 0.6}Sr{sub 0,4}Fe{sub 0,4}Co{sub 0,6}O{sub 3} were prepared by a polymeric method with the purpose of using them as cathodes in SOFCs. The electrochemical cell was mounted utilizing YSZ (ZrO{sub 2} - 8 mol%Y{sub 2}O{sub 3}) disks as electrolyte, where a paste containing Pt was calcined onto one face while the other one was covered with the oxide materials synthesized ('screen printing'). The oxide materials prepared were characterized by X-ray diffraction, transmission electronic microscopy and thermogravimetry. The oxygen reduction reaction was studied by taking polarization curves in oxygen and/or air (800 deg C a 950 deg C). The best performance was obtained for 15 {mu}m thickness electrodes La{sub 0.6}Sr{sub 0,4}MnO{sub 3} and La{sub 0.6}Sr{sub 0,4}MnO{sub 3} with addition of dispersed Pt. (author)

  4. Clearing up the kinetics in high temperature fuel cells SOFC. Final report; Aufklaerung der Kinetik in Hochtemperatur-Brennstoffzellen SOFC. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stimming, U

    1997-05-12

    In this work, the kinetics of the oxygen reduction of the SOFC cathode are to be detailed, i.e., depending on the parameters of electrode potential, temperature and oxygen partial pressure, they are to be examined with impedance spectroscopy and quasi-stationary current/voltage measurements. From the dependence of the impedances and the current density on the temperature and the oxygen partial pressure, apparent activation energies and pre-exponential factors as well as apparent reaction orders are to be determined, in order to obtain information on possible reaction mechanisms. These investigations should be carried out not only on standard cathode material (La{sub 1-x}Sr{sub x}MnO{sub 3}, LSM) but also on modified LSM cathodes. This modification should consist either of the addition of noble metal catalysts or in a change of the composition of the cathode material, and should lead to increased catalytic activity of the cathode. In addition, using the example of the standard cathode, different possible reaction mechanisms should be compared by a computer simulation of the current/voltage measurements and impedance spectra. (orig.) [Deutsch] In dieser Arbeit soll die Kinetik der Sauerstoffreduktion an der SOFC Kathode detailliert, d.h. in Abhaengigkeit der Parameter Elektrodenpotential, Temperatur und Sauerstoffpartialdruck mit Impedanzspektroskopie und quasi-stationaeren Strom/Spannungsmessungen untersucht werden. Aus den Abhaengigkeiten der Impedanzen und der Stromdichte von der Temperatur und vom Sauerstoffpartialdruck sollen scheinbare Aktivierungsenergien und prae-exponentielle Faktoren sowie scheinbare Reaktionsordnungen bestimmt werden, um Hinweise auf moegliche Reaktionsmechanismen zu erhalten. Diese Untersuchungen sollen nicht nur am Standardkathodenmaterial (La{sub 1-x}Sr{sub x}MnO{sub 3}, LSM), sondern auch an modifizierten LSM-Kathoden durchgefuehrt werden. Diese Modifizierung soll entweder im Zusatz von Edelmetallkatalysatoren oder in einer Aenderung

  5. Recent Progress in Development and Manufacturing of SOFC at Topsoe Fuel Cell A/S and Risø DTU

    DEFF Research Database (Denmark)

    Christiansen, Niels; Holm-Larsen, Helge; Primdahl, Søren

    2011-01-01

    effort is directed towards improvement of current generations as well as development of the next generation SOFC technology. The innovative concept of the next generation, aiming at improved reliability and robustness, is based on metal-supported cells and nano-structured electrodes with perspectives...

  6. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte

  7. Evidence of the Current Collector Effect: Study of the SOFC Cathode Material Ca3Co4O9+d

    NARCIS (Netherlands)

    Rolle, A.; Thoréton, V.; Rozier, P.; Capoen, E.; Mentré, O.; Boukamp, Bernard A.; Daviero-Minaud, S.

    2012-01-01

    In the study of the performance of solid oxide fuel cell (SOFC) electrodes, the possible influence of the applied current collector is often not mentioned or recognized. In this article, as part of an optimization study of the potentially attractive Ca3Co4O9+δ cathode material (Ca349), special

  8. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part B: Applications

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-09-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced pressurised and atmospheric plant configurations (SOFC + GT and SOFC + ST, with fuel cell integration within a gas turbine or a steam turbine cycle) without CO2 separation. This Part B paper investigates such kind of power cycles when applied to CO2 capture, proposing two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs with internal reforming and low temperature CO2 separation process. The power plants are simulated at the 100 MW scale with a set of realistic assumptions about FC performances, main components and auxiliaries, and show the capability of exceeding 70% LHV efficiency with high CO2 capture (above 80%) and a low specific primary energy consumption for the CO2 avoided (1.1-2.4 MJ kg-1). Detailed results are presented in terms of energy and material balances, and a sensitivity analysis of plant performance is developed vs. FC voltage and fuel utilisation to investigate possible long-term improvements. Options for further improvement of the CO2 capture efficiency are also addressed.

  9. High temperature electrolyte supported Ni-GDC/YSZ/LSM SOFC operation on two-stage Viking gasifier product gas

    DEFF Research Database (Denmark)

    Hofmann, P.; Schweiger, A.; Fryda, L.

    2007-01-01

    and tar traces. The chosen SOFC was electrolyte supported with a nickel/gadolinium-doped cerium oxide (Ni-GDC) anode, known for its carbon deposition resistance. Through humidification the steam to carbon ratio (S/C) was adjusted to 0.5, which results in a thermodynamically carbon free condition...

  10. Towards retrofitting integrated gasification combined cycle (IGCC) power plants with solid oxide fuel cells (SOFC) and CO

    NARCIS (Netherlands)

    Thallam Thattai, A.; Oldenbroek, V.D.W.M.; Schoenmakers, L; Woudstra, T.; Purushothaman Vellayani, A.

    2017-01-01

    This article presents a detailed thermodynamic case study based on the Willem-Alexander Centrale (WAC) power plant in the Netherlands towards retrofitting SOFCs in existing IGCC power plants with a focus on near future implementation. Two systems with high percentage (up to 70%) biomass

  11. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture : Part B: Applications

    NARCIS (Netherlands)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-01-01

    An important advantage of solid oxide fuel cells (SOFC) as future systems for large scale power generation is the possibility of being efficiently integrated with processes for CO2 capture. Focusing on natural gas power generation, Part A of this work assessed the performances of advanced

  12. Planarity certification of ATLAS Micromegas detector panels

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Ralph; Biebel, Otmar; Bortfeldt, Jonathan; Flierl, Bernhard; Hertenberger, Ralf; Loesel, Philipp; Herrmann, Maximilian [LMU Muenchen (Germany); Zibell, Andre [JMU Wuerzburg (Germany)

    2016-07-01

    During the second long LHC shutdown, 2019/20, the precision tracking detectors of the ATLAS muon spectrometer in the inner end caps will be replaced using Micromegas, a planar gas-detector technology. Modules of 2 m{sup 2} area are built in quadruplets from five precisely planar sandwich panels that define the anodes and the cathodes of the four active detector planes. A panel is composed of three consecutive layers FR4 - aluminum honeycomb - FR4. Single plane spatial particle resolution below 100 μm is achievable when the deviations from planarity of the strip-anodes do not exceed 80 μm RMS over the whole active area and the parallelism of the readout strips is within 30 μm. In order to measure the dimensional accuracy of each panel, laser distance sensors combined with a coordinate measurement system have been investigated. The sensor requirements to measure the planarity of the panels are a resolution of 0.3 μm and a beam spot diameter of ∼20 μm, well below 100 μ m the size of the smallest structures. We report on achieved planarities of the panels and the performance of the laser sensor system. A panel with an RMS better than 30 μm was build and the evolution of its planarity due to humidity and temperature effects is shown.

  13. Continued SOFC cell and stack technology and improved production methods

    Energy Technology Data Exchange (ETDEWEB)

    Wandel, M.; Brodersen, K.; Phair, J. (and others)

    2009-05-15

    Within this project significant results are obtained on a number of very diverse areas ranging from development of cell production, metallic creep in interconnect to assembling and test of stacks with foot print larger than 500 cm2. Out of 38 milestones 28 have been fulfilled and 10 have been partly fulfilled. This project has focused on three main areas: 1) The continued cell development and optimization of manufacturing processes aiming at production of large foot-print cells, improving cell performance and development environmentally more benign production methods. 2) Stack technology - especially stacks with large foot print and improving the stack design with respect to flow geometry and gas leakages. 3) Development of stack components with emphasis on sealing (for 2G as well as 3G), interconnect (coat, architecture and creep) and test development. Production of cells with a foot print larger than 500 cm2 is very difficult due to the brittleness of the cells and great effort has been put into this topic. Eight cells were successfully produced making it possible to assemble and test a real stack thereby giving valuable results on the prospects of stacks with large foot print. However, the yield rate is very low and a significant development to increase this yield lies ahead. Several lessons were learned on the stack level regarding 'large foot print' stacks. Modelling studies showed that the width of the cell primarily is limited by production and handling of the cell whereas the length (in the flow direction) is limited by e.g. pressure drop and necessary manifolding. The optimal cell size in the flow direction was calculated to be between approx20 cm and < 30 cm. From an economical point of view the production yield is crucial and stacks with large foot print cell area are only feasible if the cell production yield is significantly enhanced. Co-casting has been pursued as a production technique due to the possibilities in large scale production

  14. SOFC direct fuelling with high-methane gases: Optimal strategies for fuel dilution and upgrade to avoid quick degradation

    International Nuclear Information System (INIS)

    Baldinelli, A.; Barelli, L.; Bidini, G.; Di Michele, A.; Vivani, R.

    2016-01-01

    Highlights: • SOFCs are operated on natural gas and biogas direct feeding. • Methane partial oxidation and dry reforming are compared. • The optimal oxygen-to-carbon stoichiometry to avoid degradation is determined for both natural gas and biogas. • NiYSZ anodes degradation mechanisms are investigated though SEM-EDX and XRD. - Abstract: In the outlook of the transition to the carbon-free society, low-carbon gases, such as natural gas or biogas, are very promising. The first is commonly used for stationary applications based on Solid Oxide Fuel Cells (SOFCs) equipped with external reformers. Similar installations are required when the SOFC is run on biogas. Yet, high SOFC operative temperature enables internal decomposition of light hydrocarbons, therefore allowing the suppression of external reforming. Evidently, this brings about benefits in terms of system complexity and cost reduction. Nonetheless, unlike reformate fuels, direct exposure to large amount of methane favours SOFC anodes degradation. Implementing a systematic experimental approach, this paper aims at determining a simple operative strategy to carry out direct feeding without meeting with quick degradation issues, producing interesting outcomes with regards to the management of SOFC-based systems. Particularly, the regulation of the oxygen-to-carbon (O/C) relative fraction of the fuel through air addition to natural gas and partial CO_2 separation from biogas is helpful in the prevention of those mechanisms. In this study, NiYSZ anode SOFCs are exposed to air-diluted natural gas and upgraded biogas, featuring O/C between 0.2 and 1.2. Tracing these cases, at 800 °C and 500 mA/cm"2 constant load, cell performances are measured over a time interval of 100 h. Finally, post-mortem analysis is performed on the specimens to investigate material morphological changes after the exposure to high-methane fuels. Results showed that O/C = 0.8 (+63% air) is the best case to employ air-diluted natural gas

  15. Tuner and radiation shield for planar electron paramagnetic resonance microresonators

    International Nuclear Information System (INIS)

    Narkowicz, Ryszard; Suter, Dieter

    2015-01-01

    Planar microresonators provide a large boost of sensitivity for small samples. They can be manufactured lithographically to a wide range of target parameters. The coupler between the resonator and the microwave feedline can be integrated into this design. To optimize the coupling and to compensate manufacturing tolerances, it is sometimes desirable to have a tuning element available that can be adjusted when the resonator is connected to the spectrometer. This paper presents a simple design that allows one to bring undercoupled resonators into the condition for critical coupling. In addition, it also reduces radiation losses and thereby increases the quality factor and the sensitivity of the resonator

  16. Application of Planar Broadband Slow-Wave Systems

    Directory of Open Access Journals (Sweden)

    Edvardas Metlevskis

    2012-04-01

    Full Text Available Different types of planar broadband slow-wave systems are used for designing microwave devices. The papers published by Lithuanian scientists analyze and investigate the models of helical and meander slow-wave systems. The article carefully examines the applications of meander slow-wave systems and presents the areas where similar systems, e.g. mobile devices, RFID, wireless technologies are used and reviewed nowadays. The paper also focuses on the examples of the papers discussing antennas, filters and couplers that contain designed and fabricated meander slow-wave systems.Article in Lithuanian

  17. Maturing of SOFC cell and stack production technology and preparation for demonstration of SOFC stacks. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    2006-07-01

    The TOFC/Riso pilot plant production facility for the manufacture of anode-supported cells has been further up-scaled with an automated continuous spraying process and an extra sintering capacity resulting in production capacity exceeding 15,000 standard cells (12x12 cm2) in 2006 with a success rate of about 85% in the cell production. All processing steps such as tape-casting, spraying, screen-printing and atmospheric air sintering in the cell production have been selected on condition that up-scaling and cost effective, flexible, industrial mass production are feasible. The standard cell size is currently being increased to 18x18 cm2, and 150 cells of this size have been produced in 2006 for our further stack development. To improve quality and lower production cost, a new screen printing line is under establishment. TOFC's stack design is an ultra compact multilayer assembly of cells (including contact layers), metallic interconnects, spacer frames and glass seals. The compactness ensures minimized material consumption and low cost. Standard stacks with cross flow configuration contains 75 cells (12x12cm2) delivering about 1.2 kW at optimal operation conditions with pre-reformed NG as fuel. Stable performance has been demonstrated for 500-1000 hours. Significantly improved materials, especially concerning the metallic interconnect and the coatings have been introduced during the last year. Small stacks (5-10 cells) exhibit no detectable stack degradation using our latest cells and stack materials during test periods of 500-1000 hours. Larger stacks (50-75 cells) suffer from mal-distribution of gas and air inside the stacks, gas leakage, gas cross-over, pressure drop, and a certain loss of internal electrical contact during operation cycles. Measures have been taken to find solutions during the following development work. The stack production facilities have been improved and up-scaled. In 2006, 5 standard stacks have been assembled and burned in based on

  18. Manganates of lanthanum and strontium as cathode of fuel cells (SOFC); Manganatos de lantanio e estroncio como catodo de celulas combustiveis (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Marfran C. de; Nascimento, Rubens M. do; Martinelli, Antonio E.; Melo, Dulce M.A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    The fuel cells if constitute currently as a promising alternative modular generation of electric energy to leave of chemical energy. The SOFCs is distinguished as promising for the industry of the oil, therefore they can use the produced natural gas in the platforms as combustible, allowing generation of raised power electric.The material of cathode constituent of the cell are oxides with perovskites structure, normally doped with a earthy-alkaline element (Sr{sup +3}). In this work, two compositions of the La{sub 1-x}Sr{sub x} MnO{sub 3} system were synthesized (x = 0,15 and 0,30), through the Pechini method and after resultants of the process they were characterized by X- Ray diffraction, Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TG/DTG) and laser grain size analysis. The systems in study shown similar behavior how much to the results of absorption in the region of infra-red ray and TG/DTG, therefore if it can prove the loss of organic substance with the increase of the temperature.The average particle diameter for the two systems also increased gradually with the temperature. In general way the synthesis method was satisfactory for the formation of the perovskites phase in the two studied compositions. (author)

  19. A highly symmetrical 10 transistor 2-read/write dual-port static random access memory bitcell design in 28 nm high-k/metal-gate planar bulk CMOS technology

    Science.gov (United States)

    Ishii, Yuichiro; Tanaka, Miki; Yabuuchi, Makoto; Sawada, Yohei; Tanaka, Shinji; Nii, Koji; Lu, Tien Yu; Huang, Chun Hsien; Sian Chen, Shou; Tse Kuo, Yu; Lung, Ching Cheng; Cheng, Osbert

    2018-04-01

    We propose a highly symmetrical 10 transistor (10T) 2-read/write (2RW) dual-port (DP) static random access memory (SRAM) bitcell in 28 nm high-k/metal-gate (HKMG) planar bulk CMOS. It replaces the conventional 8T 2RW DP SRAM bitcell without any area overhead. It significantly improves the robustness of process variations and an asymmetric issue between the true and bar bitline pairs. Measured data show that read current (I read) and read static noise margin (SNM) are respectively boosted by +20% and +15 mV by introducing the proposed bitcell with enlarged pull-down (PD) and pass-gate (PG) N-channel MOSs (NMOSs). The minimum operating voltage (V min) of the proposed 256 kbit 10T DP SRAM is 0.53 V in the TT process, 25 °C under the worst access condition with read/write disturbances, and improved by 90 mV (15%) compared with the conventional one.

  20. Direct internal steam reforming of ethanol in a solid oxide fuel cell (SOFC) - A thermodynamic analysis

    International Nuclear Information System (INIS)

    Lima da Silva, Aline; De Fraga Malfatti, Celia; Heck, Nestor Cesar; Melo Halmenschlager, Cibele

    2003-01-01

    Among the various types of fuel cells, the solid oxide fuel cell (SOFC) has attracted considerable interest due to the possibility for operation with an internal reformer and higher system efficiency. In SOFC, high operative temperature allows the direct conversion of ethanol into H 2 and CO to take place in the electrochemical cell. Ethanol is considered to be an attractive fuel because it is a renewable energy source and presents some advantages over other green fuels such as safety in storage and handling. Direct internal reforming of ethanol, however, can produce undesirable products that diminish system efficiency and, in the case of carbon deposition over the anode, promote the growth of carbon filaments attached to the anode crystallites which generate massive forces within the electrode structure leading to its rapid breakdown. In this context, a thermodynamic analysis is fundamental to predict the product distribution as well as the conditions favorable for carbon to precipitate inside the cell. Despite of such importance, there are few works in literature dealing with thermodynamic analysis of the direct internal steam reforming of ethanol in fuel cell systems. Hence, the aim of this work is to find appropriate ranges for operating conditions where carbon deposition in SOFC with direct internal reforming operation is not feasible, in temperature range of 500- 1200K. The calculation here is more complicated than that for a reformer because the disappearance of hydrogen and the generation of H 2 O from electrochemical reaction must be taken into account. In the present study, the effects of hydrogen consumption on anode components and on carbon formation are investigated. Equilibrium determinations are performed by the Gibbs energy minimization method, considering the following species: H 2 , H 2 O, CH 4 , CO, CO 2 and C gr . (graphite). The effect of the type of solid electrolyte (oxygen-conducting and hydrogen-conducting) on carbon formation is also

  1. Pressurized Operation of a Planar Solid Oxide Cell Stack

    DEFF Research Database (Denmark)

    Jensen, Søren Højgaard; Sun, Xiufu; Ebbesen, Sune Dalgaard

    2016-01-01

    , pressurized SOEC based electrolyzers can become more efficient both energy- and cost-wise than PEM and Alkaline systems. Pressurization of SOFCs can significantly increase the cell power density and reduce the size of auxiliary components. In the present study, a SOC stack was successfully operated......Solid oxide cells (SOCs) can be operated either as fuel cells (SOFC) to convert fuels to electricity or as electrolyzers (SOEC) to convert electricity to fuels such as hydrogen or methane. Pressurized operation of SOCs provide several benefits on both cell and system level. If successfully matured...

  2. Sense of community and its relationship with walking and neighborhood design.

    Science.gov (United States)

    Wood, Lisa; Frank, Lawrence D; Giles-Corti, Billie

    2010-05-01

    The aim of this study is to examine the association between sense of community, walking, and neighborhood design characteristics. The current study is based on a sub-sample of participants (n=609) from the US Atlanta SMARTRAQ study who completed a telephone survey capturing physical activity patterns, neighborhood perceptions, and social interactions. Objective measures of neighborhood form were also computed. Univariate and multivariate models (General Linear Models (GLM)) were used to examine the association between sense of community (SofC) and aspects of the built environment, physical activity, and neighborhood perceptions. In multivariate models the impact on SofC was examined with progressive adjustment for demographics characteristics followed by walking behavior, neighborhood design features, neighborhood perceptions and time spent traveling in a car. After adjustment, SofC was positively associated with leisurely walking (days/week), home ownership, seeing neighbors when walking and the presence of interesting sites. SofC was also associated with higher commercial floor space to land area ratios (FAR) - a proxy for walkable site design that captures the degree to which retail destinations are set back from the street, the amount of surface parking, and urban design of an area. Conversely the presence of more mixed use and perceptions of steep hills were inversely associated with SofC. SofC is enhanced by living in areas that encourage leisurely walking, hence it is associated with living in neighbourhoods with lower levels of land use mix, but higher levels of commercial FAR. Our results suggest that in terms of SofC, the presence of commercial destinations may inhibit social interaction among local residents unless urban design is used to create convivial pedestrian-friendly commercial areas, e.g., providing street frontage, rather than flat surface parking. This finding has policy implications and warrants further investigation. Copyright 2010 Elsevier

  3. A Brief Description of High Temperature Solid Oxide Fuel Cell’s Operation, Materials, Design, Fabrication Technologies and Performance

    Directory of Open Access Journals (Sweden)

    Muneeb Irshad

    2016-03-01

    Full Text Available Today’s world needs highly efficient systems that can fulfill the growing demand for energy. One of the promising solutions is the fuel cell. Solid oxide fuel cell (SOFC is considered by many developed countries as an alternative solution of energy in near future. A lot of efforts have been made during last decade to make it commercial by reducing its cost and increasing its durability. Different materials, designs and fabrication technologies have been developed and tested to make it more cost effective and stable. This article is focused on the advancements made in the field of high temperature SOFC. High temperature SOFC does not need any precious catalyst for its operation, unlike in other types of fuel cell. Different conventional and innovative materials have been discussed along with properties and effects on the performance of SOFC’s components (electrolyte anode, cathode, interconnect and sealing materials. Advancements made in the field of cell and stack design are also explored along with hurdles coming in their fabrication and performance. This article also gives an overview of methods required for the fabrication of different components of SOFC. The flexibility of SOFC in terms fuel has also been discussed. Performance of the SOFC with varying combination of electrolyte, anode, cathode and fuel is also described in this article.

  4. Feasibility study of solid oxide fuel cell engines integrated with sprinter gas turbines: Modeling, design and control

    Science.gov (United States)

    Jia, Zhenzhong; Sun, Jing; Dobbs, Herb; King, Joel

    2015-02-01

    Conventional recuperating solid oxide fuel cell (SOFC)/gas turbine (GT) system suffers from its poor dynamic capability and load following performance. To meet the fast, safe and efficient load following requirements for mobile applications, a sprinter SOFC/GT system concept is proposed in this paper. In the proposed system, an SOFC stack operating at fairly constant temperature provides the baseline power with high efficiency while the fast dynamic capability of the GT-generator is fully explored for fast dynamic load following. System design and control studies have been conducted by using an SOFC/GT system model consisting of experimentally-verified component models. In particular, through analysis of the steady-state simulation results, an SOFC operation strategy is proposed to maintain fairly constant SOFC power (less than 2% power variation) and temperature (less than 2 K temperature variation) over the entire load range. A system design procedure well-suited to the proposed system has also been developed to help determining component sizes and the reference steady-state operation line. In addition, control analysis has been studied for both steady-state and transient operations. Simulation results suggest that the proposed system holds the promise to achieve fast and safe transient operations by taking full advantage of the fast dynamics of the GT-generator.

  5. Microstructure degradation of LSM-YSZ cathode in SOFCs operated at various conditions

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Thydén, Karl Tor Sune; Chen, Ming

    2012-01-01

    Systematic microstructural analyses have been carried out on a series of technological SOFCs that went through long-term cell tests with various operating parameters including temperature, current load and time length under current. For the LSM-YSZ cathode, a number of microstructure degradation...... mechanisms have been identified. And it has been observed that different mechanisms dominate the degradation process under different test conditions. The severe cathode degradation at 750 °C operation with high current density is attributed to a loss of the cathode/electrolyte interface stability....... For the cells tested at 850 °C, the interface stability is maintained due to further sintering during cell operation. A cell test lasting for 2 years (17500 h) at 850 °C with a moderate current density (not greater than 1 A/cm2) has shown that the cathode microstructure is fairly robust to the degradation...

  6. Microstructural studies on degradation of interface between LSM–YSZ cathode and YSZ electrolyte in SOFCs

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Hagen, Anke; Barfod, Rasmus

    2009-01-01

    The changes in the cathode/electrolyte interface microstructure have been studied on anode-supported technological solid oxide fuel cells (SOFCs) that were subjected to long-term (1500 h) testing at 750 °C under high electrical loading (a current density of 0.75 A/cm2). These cells exhibit...... different cathode degradation rates depending on, among others, the composition of the cathode gas, being significantly smaller in oxygen than in air. FE-SEM and high resolution analytical TEM were applied for characterization of the interface on a submicron- and nano-scale. The interface degradation has...... to decrease further due to the more pronounced formation of insulating zirconate phases that are present locally and preferably in LSM/YSZ electrolyte contact areas. The effects of the cathode gas on the interface degradation are discussed considering the change of oxygen activity at the interface, possible...

  7. In situ observations of microstructural changes in SOFC anodes during redox cycling

    DEFF Research Database (Denmark)

    Klemensø, Trine; Appel, C. C.; Mogensen, Mogens Bjerg

    2006-01-01

    The anode-supported solid oxide fuel cell (SOFC) degrades when the anode is subjected to redox cycling. The degradation has qualitatively been related to microstructural changes in the nickel-yttria stabilized zirconia anode of the tested cells. In this work, the microstructural changes were...... observed in situ using environmental scanning electron microscopy. In the reduced state, a dynamic rounding of the nickel particles occurred. The oxide growth upon re-oxidation depended on the oxidation kinetics. During rapid oxidation, the NiO particles divided into 2-4 particles, which grew...... into the surrounding voids. For slower oxidation, an external oxide layer was seen to develop around the individual particles. (c) 2006 The Electrochemical Society....

  8. Application of Coordinated SOFC and SMES Robust Control for Stabilizing Tie-Line Power

    Energy Technology Data Exchange (ETDEWEB)

    Ning Zhang; Wei Gu; Haojun Yu; Wei Liu [School of Electrical Engineering, Southeast University, Nanjing (China)

    2013-04-15

    Wind power causes fluctuations in power systems and introduces issues concerning system stability and power quality because of the lack of controllability of its discontinuous and intermittent resources. This paper presents a coordinated control strategy for solid oxide fuel cells (SOFCs) and superconducting magnetic energy storage (SMES) to match the intermittent wind power generation and compensate for the rapid load changes. An optimal H{sub {infinity}}control method, where the weighting function selection is expressed as an optimization problem, is proposed to mitigate tie-line power fluctuations and the mixed-sensitivity approach is used to deal with the interference suppression. Simulation results show that the proposed method significantly improves the smoothing effect of wind power fluctuations. Compared with the conventional control method, the proposed method has better anti-interference performance in various operating situations.

  9. Electrochemical Characterization and Degradation Analysis of Large SOFC Stacks by Impedance Spectroscopy

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.

    2013-01-01

    As solid oxide fuel cell (SOFC) technology is moving closer to a commercial break through, lifetime limiting factors, and methods to measure the “state-of-health” of operating cells and stacks are becoming of increasing interest. This requires application of advanced methods for detailed...... electrochemical characterization during operation. An experimental stack with low ohmic resistance from Topsoe Fuel Cell A/S was characterized in detail using electrochemical impedance spectroscopy (EIS). An investigation of the optimal geometrical placement of the current feeds and voltage probes was carried out...... with hydrogen as fuel with 52% fuel utilization and constant current load (0.2 A cm–2) at 750 °C. Stack interconnects were coated with six different coatings to prevent chromium poisoning on the cathode side. Four repeating units (RUs) with different coatings were selected for detailed impedance analysis. EIS...

  10. Effect of Humidity in Air on Performance and Long-Term Durability of SOFCs

    DEFF Research Database (Denmark)

    Hagen, Anke; Neufeld, Kai; Liu, Yi-Lin

    2010-01-01

    Anode-supported solid oxide fuel cells (SOFCs) based on Ni–yttria-stabilized zirconia (YSZ) anodes, YSZ electrolytes, and lanthanum strontium manganite (LSM)–YSZ cathodes were studied with respect to durability in humid air (~4%) typically over 1500 h. Operating temperature and current density were...... varied between 750 and 850°C and 0.25–0.75 A/cm2, respectively. The introduction of humidity affected the cell voltage under polarization of the cell, and this effect was (at least partly) reversible upon switching off the humidity. Generally, the studied cells were operated in humid air under...... technologically relevant conditions over more than 1500 h. Improvements at the cathode/electrolyte interface made it possible to obtain highly stable cells, which can be operated under high current density and at 750°C in humid air, conditions that cause significant cell voltage degradation in dry air on cells...

  11. Effect of Humidity in Air on Performance and Long-Term Durability of SOFCs

    DEFF Research Database (Denmark)

    Hagen, Anke; Chen, Ming; Neufeld, Kai

    2009-01-01

    Anode supported SOFCs based on Ni-YSZ anodes, YSZ electrolytes, and LSM-YSZ cathodes were studied with respect to durability in humid air (~4%) over typically 1500 hours. Operating temperature and current density were varied between 750 and 850 oC and 0.25-0.75 A/cm2, respectively. It was found...... that the introduction of humidity affected the cell voltage under polarization of the cell and that this effect was (at least partly) reversible upon switching off the humidity, probably related to a segregation of impurities towards the three phase boundary in the presence of humidity. Generally, the studied cells...... were successfully operated in humid air under technologically relevant conditions. Improvements at the cathode/electrolyte interface made it possible to obtain highly stable cells, which can be operated under high current density and at 750 oC in humid air - conditions that are known to cause...

  12. Properties and Performance of SOFCs Produced on a Pre-Pilot Plant Scale

    DEFF Research Database (Denmark)

    Hagen, Anke; Menon, Mohan; Barfod, Rasmus

    2006-01-01

    specific cell resistance at 850 °C was found to be 0.24 Ω cm2 with a standard deviation of 0.05 Ω cm2. The variation in performance between the cells can be largely attributed to variations in the cathode performance. Experimental evidence will be presented on full 4 × 4 cm2 cells, symmetric cells with two......In the present paper, anode supported solid oxide fuel cells (SOFCs), produced on a pre-pilot plant scale in ten batches of ∼100 cells, are characterised with respect to performance. The main purpose was to evaluate the reproducibility of the scaled-up process. Based on 20 tests, the average area...

  13. Mechanical Behaviour of Glassy Composite Seals for IT-SOFC Application

    DEFF Research Database (Denmark)

    Nielsen, Karsten Agersted; Solvang, Mette; Nielsen, Sofie Birkedal Lund

    2007-01-01

    Glass-based sealants have been developed with emphasis on filler material and surface treatment of the sealing components in order to optimise their mechanical and functional behaviour during the initial sealing process as well as during thermal cycling of the SOFC-stack after exposure to operating...... conditions. The bonding strength and microstructure of the interfaces between composite seals and interconnect materials were investigated as a function of surface treatment of the sealing surfaces, glass matrix composition, sealing pressure and temperature. The initial sealing performance and resistance...... to thermal cycling were then investigated on selected combinations of materials after ageing. Strongest bonding between sodium aluminosilicate glass composite and steel surfaces was obtained for sealing at 850°C. For the strongest interface, having shear strength of 2.35 MPa, rupture occurred in the glass...

  14. Impedance of porous IT-SOFC LSCF:CGO composite cathodes

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jacobsen, Torben; Wandel, Marie

    2011-01-01

    The impedance of technological relevant LSCF:CGO composite IT-SOFC cathodes was studied over a very wide performance range. This was experimentally achieved by impedance measurements on symmetrical cells with three different microstructures in the temperature range 550–850 °C. In order to account...... for the impedance spectra of the poor performing cathodes the Finite-Length-Gerischer (FLG) impedance was derived and applied to the impedance data. The FLG impedance describes for a given microstructure the situation where the cathode is made too thin from a cathode development point of view. The moderate...... performing cathodes showed a slightly suppressed Gerischer impedance, while the impedance spectra of the well performing cathodes showed the presence of an arc due to oxygen gas diffusion. The overall impedance of the well performing cathodes could be described with a slightly suppressed Gerischer impedance...

  15. Application of Coordinated SOFC and SMES Robust Control for Stabilizing Tie-Line Power

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2013-04-01

    Full Text Available Wind power causes fluctuations in power systems and introduces issues concerning system stability and power quality because of the lack of controllability of its discontinuous and intermittent resources. This paper presents a coordinated control strategy for solid oxide fuel cells (SOFCs and superconducting magnetic energy storage (SMES to match the intermittent wind power generation and compensate for the rapid load changes. An optimal H∞ control method, where the weighting function selection is expressed as an optimization problem, is proposed to mitigate tie-line power fluctuations and the mixed-sensitivity approach is used to deal with the interference suppression. Simulation results show that the proposed method significantly improves the smoothing effect of wind power fluctuations. Compared with the conventional control method, the proposed method has better anti-interference performance in various operating situations.

  16. Investigation of nanoporous platinum thin films fabricated by reactive sputtering: Application as micro-SOFC electrode

    Science.gov (United States)

    Jung, WooChul; Kim, Jae Jin; Tuller, Harry L.

    2015-02-01

    Highly porous Pt thin films, with nano-scale porosity, were fabricated by reactive sputtering. The strategy involved deposition of thin film PtOx at room temperature, followed by the subsequent decomposition of the oxide by rapid heat treatment. The resulting films exhibited percolating Pt networks infiltrated with interconnected nanosized pores, critical for superior solid oxide fuel cell cathode performance. This approach is particularly attractive for micro-fabricated solid oxide fuel cells, since it enables fabrication of the entire cell stack (anode/electrolyte/cathode) within the sputtering chamber, without breaking vacuum. In this work, the morphological, crystallographic and chemical properties of the porous electrode were systematically varied by control of deposition conditions. Oxygen reduction reaction kinetics were investigated by means of electrochemical impedance spectroscopy, demonstrating the critical role of nano-pores in achieving satisfactory micro-SOFC cathode performance.

  17. Fabricating Pinhole-Free YSZ Sub-Microthin Films by Magnetron Sputtering for Micro-SOFCs

    Directory of Open Access Journals (Sweden)

    T. Hill

    2011-01-01

    Full Text Available Submicron thin yttria stabilized zirconia (YSZ films were prepared on a variety of substrates with different surface morphologies by magnetron sputtering followed by thermal oxidation. Pinholes were observed in the films deposited on nanoporous alumina substrates. Initial dense Y/Zr films developed nanocracks after thermal oxidation on smooth Si wafer substrates. At optimal sputtering and oxidation conditions, smooth and crack/pore-free films were achieved on Si wafer substrates. The thin YSZ films exhibited fully ionic conduction with ionic conductivities, and activation energy corroborated well with the values from commercial YSZ plates. The thin YSZ films can be utilized in Solid Oxide Fuel Cells (SOFCs for intermediate temperature operations.

  18. A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

    KAUST Repository

    Chang, Y.-H.; Chen, S.-C.; Wang, T.-J.; Guo, J.

    2018-01-01

    Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non

  19. A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

    KAUST Repository

    Chang, Y.-H.

    2018-02-26

    Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non-planar transverse stretching process was employed in this study to produce micro-porous structure. The morphology, membrane thickness, mean pore size, and porosity of the PTFE membrane were investigated. The results show that the non-planar transverse stretched membranes exhibit more uniform average pore diameter with thinner membrane thickness. Morphological changes induced by planar and non-planar transverse stretching for pore characteristics were investigated. The stretching conditions, stretching temperature and rate, affect the stretched membrane. Increasing temperature facilitated the uniformity of pore size and uniformity of membrane thickness. Moreover, increase in stretching rate resulted in finer pore size and thinner membrane.

  20. Characterization of printed planar electromagnetic coils using digital extrusion and roll-to-roll flexographic processes

    Science.gov (United States)

    Rickard, Scott

    Electromagnets are a crucial component in a wide range of more complex electrical devices due to their ability to turn electrical energy into mechanical energy and vice versa. The trend for electronics becoming smaller and lighter has led to increased interest in using flat, planar electromagnetic coils, which have been shown to perform better at scaled down sizes. The two-dimensional geometry of a planar electromagnetic coil yields itself to be produced by a roll-to-roll additive manufacturing process. The emergence of the printed electronics field, which uses traditional printing processes to pattern functional inks, has led to new methods of mass-producing basic electrical components. The ability to print a planar electromagnetic coil using printed electronics could rival the traditional subtractive and semi-subtractive PCB process of manufacturing. The ability to print lightweight planar electromagnetic coils on flexible substrates could lead to their inclusion into intelligent packaging applications and could have specific use in actuating devices, transformers, and electromagnetic induction applications such as energy harvesting or wireless charging. In attempts to better understand the limitations of printing planar electromagnetic coils, the effect that the design parameters of the planar coils have on the achievable magnetic field strength were researched. A comparison between prototyping methods of digital extrusion and manufacturing scale flexographic printing are presented, discussing consistency in the printed coils and their performance in generating magnetic fields. A method to predict the performance of these planar coils is introduced to allow for design within required needs of an application. Results from the research include a demonstration of a printed coil being used in a flat speaker design, working off of actuating principles.

  1. Evanescent field refractometry in planar optical fiber.

    Science.gov (United States)

    Holmes, Christopher; Jantzen, Alexander; Gray, Alan C; Gow, Paul C; Carpenter, Lewis G; Bannerman, Rex H S; Gates, James C; Smith, Peter G R

    2018-02-15

    This Letter demonstrates a refractometer in integrated optical fiber, a new optical platform that planarizes fiber using flame hydrolysis deposition (FHD). The unique advantage of the technology is survivability in harsh environments. The platform is mechanically robust, and can survive elevated temperatures approaching 1000°C and exposure to common solvents, including acetone, gasoline, and methanol. For the demonstrated refractometer, fabrication was achieved through wet etching an SMF-28 fiber to a diameter of 8 μm before FHD planarization. An external refractive index was monitored using fiber Bragg gratings (FBGs), written into the core of the planarized fiber. A direct comparison to alternative FBG refractometers is made, for which the developed platform is shown to have comparable sensitivity, with the added advantage of survivability in harsh environments.

  2. Technical errors in planar bone scanning.

    Science.gov (United States)

    Naddaf, Sleiman Y; Collier, B David; Elgazzar, Abdelhamid H; Khalil, Magdy M

    2004-09-01

    Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

  3. Planar quantum squeezing and atom interferometry

    Energy Technology Data Exchange (ETDEWEB)

    He, Q. Y.; Drummond, P. D.; Reid, M. D. [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Peng Shiguo [Department of Physics, Tsinghua University, Beijing 100084 (China)

    2011-08-15

    We obtain a lower bound on the sum of two orthogonal spin component variances in a plane. This gives a planar uncertainty relation which holds even when the Heisenberg relation is not useful. We investigate the asymptotic, large-J limit and derive the properties of the planar quantum squeezed states that saturate this uncertainty relation. These states extend the concept of spin squeezing to any two conjugate spin directions. We show that planar quantum squeezing can be achieved experimentally as the ground state of a Bose-Einstein condensate in two coupled potential wells with a critical attractive interaction. These states reduce interferometric phase noise at all phase angles simultaneously. This is useful for one-shot interferometric phase measurements where the measured phase is completely unknown. Our results can also be used to derive entanglement criteria for multiple spins J at separated sites, with applications in quantum information.

  4. Aspects of industrial production of solid electrolyte fuel cells (SOFC) by thermal spraying technology; Aspekte industrieller Fertigung von Festelektrolyt-Brennstoffzellen (SOFC) mittels thermischer Beschichtungsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Weckmann, Hannes

    2010-07-01

    The present thesis deals with measures to optimize the large-volume production of Solid Oxide Fuel Cells (SOFC) based on thermal spraying technology. Based on the well-established Vacuum Plasma Spraying (VPS) at DLR the potential of alternative thermal spraying techniques as well as alternative base materials was investigated in order to deposit SOFC-anode, electrolyte and insulating layers. Production costs, reproducibility and long-term stability of the production process as well as the fuel cell performance were major target criteria. Depending on the parameter set applied when using the cost efficient Atmospheric Plasma Spraying (APS) in combination with Nickel-Graphite as base material a significant improvement of gas permeability and electrical conductivity was achieved in comparison to the VPS sprayed reference anode. The power density of a fuel cell with an APS-Nickel-Graphite anode (184 mW/cm{sup 2}) was slightly better than the performance with a VPS reference anode (159 mW/cm{sup 2}). In comparison to the VPS process, ceramic electrolyte layers of fully stabilized Zirconia (YSZ) with significantly higher gas tightness could be demonstrated when high energy processes such as Low Pressure Plasma Spraying (LPPS). Thin-film Low Pressure Plasma Spraying (LPPS-Thin-film) and High Velocity Oxy Fuel Spraying (HVOF) were applied. The power density of a fuel cell equipped with an HVOF electrolyte was significantly improved to 234 mW/cm{sup 2} as compared to 187 mW/cm{sup 2} with the VPS sprayed reference cell. Further improvement of the power density was achieved with an LPPS-electrolyte (273 mW/cm{sup 2}). HVOF and VPS sprayed layers of pure Spinel in composite with metallic active braze (equivalent to the sealing between individual layers in the fuel cell stack) could exceed the demanded charge transfer resistance of >1 k{omega}cm{sup 2} at 800 C operating temperature only in few cases. When blended base powder of Spinel and Magnesia in combination with the VPS

  5. Investigation for connecting waveguide in off-planar integrated circuits.

    Science.gov (United States)

    Lin, Jie; Feng, Zhifang

    2017-09-01

    The transmission properties of a vertical waveguide connected by different devices in off-planar integrated circuits are designed, investigated, and analyzed in detail by the finite-difference time-domain method. The results show that both guide bandwidth and transmission efficiency can be adjusted effectively by shifting the vertical waveguide continuously. Surprisingly, the wide guide band (0.385[c/a]∼0.407[c/a]) and well transmission (-6  dB) are observed simultaneously in several directions when the vertical waveguide is located at a specific location. The results are very important for all-optical integrated circuits, especially in compact integration.

  6. Highly-dispersive electromagnetic induced transparency in planar symmetric metamaterials.

    Science.gov (United States)

    Lu, Xiqun; Shi, Jinhui; Liu, Ran; Guan, Chunying

    2012-07-30

    We propose, design and experimentally demonstrate highly-dispersive electromagnetically induced transparency (EIT) in planar symmetric metamaterials actively switched and controlled by angles of incidence. Full-wave simulation and measurement results show EIT phenomena, trapped-mode excitations and the associated local field enhancement of two symmetric metamaterials consisting of symmetrically split rings (SSR) and a fishscale (FS) metamaterial pattern, respectively, strongly depend on angles of incidence. The FS metamaterial shows much broader spectral splitting than the SSR metamaterial due to the surface current distribution variation.

  7. Planar shock focusing through perfect gas lens: First experimental demonstration

    International Nuclear Information System (INIS)

    Biamino, Laurent; Mariani, Christian; Jourdan, Georges; Houas, Lazhar; Vandenboomgaerde, Marc; Souffland, Denis

    2014-01-01

    When a shock wave crosses an interface between two materials, this interface becomes unstable and the Richtmyer-Meshkov instability develops. Such instability has been extensively studied in the planar case, and numerous results were presented during the previous workshops. But the Richtmyer-Meshkov (Richtmyer, 1960, 'Taylor Instability in Shock Acceleration of Compressible Fluids,' Commun. Pure Appl. Math., 13(2), pp. 297-319; Meshkov, 1969, 'Interface of Two Gases Accelerated by a Shock Wave,' Fluid Dyn., 4(5), pp. 101-104) instability also occurs in a spherical case where the convergence effects must be taken into account. As far as we know, no conventional (straight section) shock tube facility has been used to experimentally study the Richtmyer-Meshkov instability in spherical geometry. The idea originally proposed by Dimotakis and Samtaney (2006, 'Planar Shock Cylindrical Focusing by a Perfect-Gas Lens,' Phys. Fluid., 18(3), pp. 031705-031708) and later generalized by Vandenboomgaerde and Aymard (2011, 'Analytical Theory for Planar Shock Focusing Through Perfect Gas Lens and Shock Tube Experiment Designs,' Phys. Fluid., 23(1), pp. 016101-016113) was to retain the flexibility of a conventional shock tube to convert a planar shock wave into a cylindrical one through a perfect gas lens. This can be done when a planar shock wave passes through a shaped interface between two gases. By coupling the shape with the impedance mismatch at the interface, it is possible to generate a circular transmitted shock wave. In order to experimentally check the feasibility of this approach, we have implemented the gas lens technique on a conventional shock tube with the help of a convergent test section, an elliptic stereo lithographed grid, and a nitrocellulose membrane. First experimental sequences of Schlieren images have been obtained for an incident shock wave Mach number equal to 1.15 and an air/SF_6-shaped interface. Experimental results indicate that the shock that moves

  8. Planar dynamical systems selected classical problems

    CERN Document Server

    Liu, Yirong; Huang, Wentao

    2014-01-01

    This book presents in an elementary way the recent significant developments in the qualitative theory of planar dynamical systems. The subjects are covered as follows: the studies of center and isochronous center problems, multiple Hopf bifurcations and local and global bifurcations of the equivariant planar vector fields which concern with Hilbert's 16th problem. This book is intended for graduate students, post-doctors and researchers in the area of theories and applications of dynamical systems. For all engineers who are interested the theory of dynamical systems, it is also a reasona

  9. Problem and design drawing for solution of precision design drawing and machine design

    International Nuclear Information System (INIS)

    Heo, Gil

    1982-04-01

    The contents of this book are basic of design drawing, problem of machine design, problem of precision design drawing, problem of planar figure of sheet metal, design drawing for solution of machine design, design drawing for solution of precision design drawing and design drawing for planar figure of sheet metal. It tells of the problems and gives the solutions on precision design drawing and machine design.

  10. Test laboratories for elementary cells of a solid oxide fuel cell (SOFC); Laboratoire d`essais de cellules elementaires d`une pile a combustible a oxyde solide (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Guerin, F.

    1998-01-01

    The solid oxide furl (SOFC) cell could well be the fuel most suited to stationary applications. Its high working temperature allows it to high value heat which can be used to increase electrical output (by the addition of a gas turbine), or to produce steam for heating or an industrial process. test laboratory for electrochemical cells has been created to test elementary cells whose dimensions do not exceed 5 x 5 cm. The SOFC, consisting of a ceramic sheet, is maintained in an oven at around 900 deg. C. It can produce a maximum continuous current of 25 A at a voltage of 0.7 V on an electronic charge. Each test lasts at least 500 hours. Investigation of the prototype cells is intended to establish their electrochemical characteristics: activity, ionic and electronic conductivity, polarization curve stability behaviour under fast transient electronic regime. In parallel, modelings are performed and will be validated by these different tests results

  11. Investigations on autothermal reforming of kerosene Jet A-1 for supplying solid oxide fuel cells (SOFC); Untersuchungen zur autothermen Reformierung von Kerosin Jet A-1 zur Versorgung oxidkeramischer Festelektrolyt-Brennstoffzellen (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, B.

    2007-01-25

    The auxiliary power unit of commercial aircraft is a gas turbine producing electric power with an efficiency of 18 %. This APU can be replaced by a fuel cell system, consisting of an autothermal kerosene reformer and a solid oxide fuel cell (SOFC). The fuel is kerosene Jet A-1. The autothermal reforming of Jet A-1 is practically investigated under variation of steam-to-carbon-ratio, air ratio, space velocity, time in operation and reactor pressure on commercial catalysts. Using stationary system simulation the thermodynamic processes of the device is investigated. Finally, the autothermal reformer and the SOFC consisting of 14 cells are coupled. During this test series, I-V-characteristics are measured, fuel utilisation is calculated and the self-sufficient system operation is shown. (orig.)

  12. Preparation of cathode materials for solid oxide solid fuel (SOFC) using gelatin; Preparacao de materiais catodicos para celulas a combustivel de oxido solido (SOFC) atraves do uso de gelatina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.M.; Aquino, F. de M.; Macedo, D.A. de; Sa, A.M.; Galvao, G.O., E-mail: rinaldo_mendesa@hotmail.com [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Fuel cells are electrochemical devices that convert chemical energy into electrical energy. These devices are basically divided into interconnectors, electrolyte, anode, and cathode. Recently, studies of improvements in microstructural and morphological properties of calcium cobaltate (Ca{sub 3}Co{sub 4}O{sub 9}, C349) has been made regarding its potential use as SOFC cathode for intermediate temperature. Gelatin has proven to be effective as a polymerizing agent in the synthesis of nanocrystalline materials. This work reports the synthesis and characterization of the C349 cathode using commercial gelatin. The structural properties of the material were determined by X-ray diffraction (XRD). Morphological characterization was performed by scanning electron microscopy (SEM). The results showed the formation of the crystalline phase at 900 °C, indicating the effectiveness of the gelatin in the preparation of cathodes for SOFC. (author)

  13. Sinterización de vidrios del sistema RO-BaO-SiO2 (R= Mg, Zn para el sellado de SOFC

    Directory of Open Access Journals (Sweden)

    Lara, C.

    2007-04-01

    Full Text Available Glasses of composition 50SiO2•30BaO•20ZnO, mol% (Zn1.5-50, 55SiO2•27BaO•18ZnO, mol% (Zn1.5-55, and 55SiO2•27BaO•18MgO, mol% (Mg1.5-55 present good properties for application in sealing planar solid oxide fuel cells with an intermediate temperature of operation (850ºC (IT-SOFC. The sealing must take place on sintering the glass powder during the start-up of the cell between 700 and 850ºC. Further treatment at the operation temperature provokes the crystallisation of barium silicates with the subsequent increase of viscosity and seal rigidity. This work is a study of the sintering behaviour of these glasses using different heating rates and particle-size distributions of the glass powder in order to obtain dense and homogeneous seals. The glasses Zn1.5-55 and Mg1.5-55 with a particle size less than 63 μm heated at 2ºC/min reach final densities higher than 95%. A good agreement has been demonstrated between the measured sintering kinetics and those predicted with the sintering model of Clusters formation in the absence of concurrent crystallisation.

    Los vidrios de composición molar 50SiO2•30BaO•20ZnO (Zn1.5-50, 55SiO2•27BaO•18ZnO (Zn1.5-55, y 55SiO2•27BaO•18MgO (Mg1.5-55 presentan buenas propiedades para su aplicación en el sellado de pilas de combustible de óxido sólido de configuración plana y temperatura de operación intermedia (850ºC (IT-SOFC. El sellado debe producirse a través de la sinterización del polvo de vidrio, durante el arranque de la pila, a temperaturas entre 700 y 850ºC. El tratamiento posterior a la temperatura de operación da lugar a la cristalización de silicatos de bario con el consiguiente aumento de viscosidad y rigidez del sello. Este trabajo es un estudio del comportamiento de sinterización de estos vidrios utilizando diferentes velocidades de calentamiento y distribuciones de tamaño de partícula del polvo de vidrio, para la obtención final de sellos densos y homog

  14. Stabilizing Planar Inverted Pendulum System Based on Fuzzy Nine-point Controller

    OpenAIRE

    Qi Qian; Liu Feng; Tang Yong-chuan; Yang Yang

    2013-01-01

    In order to stabilize planar inverted pendulum, after analyzing the physical characteristics of the planar inverted pendulum system, a pendulum nine-point controller and a car nine-point controller for X-axis and Y-axis were designed respectively. Then a fuzzy coordinator was designed using the fuzzy control theory based on the priority of those two controllers, and the priority level of the pendulum is higher than the car. Thus, the control tasks of each controller in each axis were harmoniz...

  15. Microphotonic devices for compact planar lightwave circuits and sensor systems

    Science.gov (United States)

    Cardenas Gonzalez, Jaime

    2005-07-01

    Higher levels of integration in planar lightwave circuits and sensor systems can reduce fabrication costs and broaden viable applications for optical network and sensor systems. For example, increased integration and functionality can lead to sensor systems that are compact enough for easy transport, rugged enough for field applications, and sensitive enough even for laboratory applications. On the other hand, more functional and compact planar lightwave circuits can make optical networks components less expensive for the metro and access markets in urban areas and allow penetration of fiber to the home. Thus, there is an important area of opportunity for increased integration to provide low cost, compact solutions in both network components and sensor systems. In this dissertation, a novel splitting structure for microcantilever deflection detection is introduced. The splitting structure is designed so that its splitting ratio is dependent on the vertical position of the microcantilever. With this structure, microcantilevers sensitized to detect different analytes or biological agents can be integrated into an array on a single chip. Additionally, the integration of a depolarizer into the optoelectronic integrated circuit in an interferometric fiber optic gyroscope is presented as a means for cost reduction. The savings come in avoiding labor intensive fiber pigtailing steps by permitting batch fabrication of these components. In particular, this dissertation focuses on the design of the waveguides and polarization rotator, and the impact of imperfect components on the performance of the depolarizer. In the area of planar lightwave circuits, this dissertation presents the development of a fabrication process for single air interface bends (SAIBs). SAIBs can increase integration by reducing the area necessary to make a waveguide bend. Fabrication and measurement of a 45° SAIB with a bend efficiency of 93.4% for TM polarization and 92.7% for TE polarization are

  16. Performance-Microstructure Relations in Ni/CGO Infiltrated Nb-doped SrTiO3 SOFC Anodes

    DEFF Research Database (Denmark)

    Ramos, Tania; Bernuy-Lopez, Carlos; Reddy Sudireddy, Bhaskar

    2012-01-01

    Nb-doped SrTiO3 solid oxide fuel cell (SOFC) anodes, infiltrated with CGO/Ni, were investigated by electrochemical impedance spectroscopy (EIS) and high resolution microscopy techniques, upon varying production and testing parameters. The electrochemical analysis involved a combination of distrib......Nb-doped SrTiO3 solid oxide fuel cell (SOFC) anodes, infiltrated with CGO/Ni, were investigated by electrochemical impedance spectroscopy (EIS) and high resolution microscopy techniques, upon varying production and testing parameters. The electrochemical analysis involved a combination...... of distribution of relaxation times (DRT) and complex non-linear least squares (CNLS) fitting routine. These electrodes were studied as singlephase or as composites with 8YSZ. Sr0.94Ti0.9Nb0.1O3-δ/ 10 vol.% 8YSZ composite infiltrated electrodes were the best overall performers, with enhanced performance stability...

  17. Operating Point Optimization of a Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Steam Turbine (SOFC-ST Plant

    Directory of Open Access Journals (Sweden)

    Juanjo Ugartemendia

    2013-09-01

    Full Text Available This paper presents a hydrogen powered hybrid solid oxide fuel cell-steam turbine (SOFC-ST system and studies its optimal operating conditions. This type of installation can be very appropriate to complement the intermittent generation of renewable energies, such as wind generation. A dynamic model of an alternative hybrid SOFC-ST configuration that is especially suited to work with hydrogen is developed. The proposed system recuperates the waste heat of the high temperature fuel cell, to feed a bottoming cycle (BC based on a steam turbine (ST. In order to optimize the behavior and performance of the system, a two-level control structure is proposed. Two controllers have been implemented for the stack temperature and fuel utilization factor. An upper supervisor generates optimal set-points in order to reach a maximal hydrogen efficiency. The simulation results obtained show that the proposed system allows one to reach high efficiencies at rated power levels.

  18. Numerical Study of Planar GPR Antenna Measurements

    DEFF Research Database (Denmark)

    Meincke, Peter; Hansen, Thorkild

    2004-01-01

    The formulation of planar near-field measurements of GPR antennas determines the plane-wave spectra of the GPR antenna in terms of measurements obtained with a buried probe as the GPR antenna moves over a scan plane on the ground. A numerical study investigates how the formulation is affected by (1...

  19. Fundamental losses in planar Bragg waveguides

    NARCIS (Netherlands)

    Vinogradov, A. V.; Mitrofanov, A. N.; Popov, A. V.; Fedin, M. A.

    2007-01-01

    This paper considers a planar Bragg waveguide. The guided modes and their dissipation due to the fundamental absorption are described. In the interacting-wave approximation, an analytical relation between the characteristics of the modes and parameters of the Bragg-waveguide geometry was

  20. Planar quark diagrams and binary spin processes

    International Nuclear Information System (INIS)

    Grigoryan, A.A.; Ivanov, N.Ya.

    1986-01-01

    Contributions of planar diagrams to the binary scattering processes are analyzed. The analysis is based on the predictions of quark-gluon picture of strong interactions for the coupling of reggeons with quarks as well as on the SU(6)-classification of hadrons. The dependence of contributions of nonplanar corrections on spins and quark composition of interacting particles is discussed