WorldWideScience

Sample records for pemfc para geracao

  1. Analysis performance of proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Mubin, A. N. A.; Bahrom, M. H.; Azri, M.; Ibrahim, Z.; Rahim, N. A.; Raihan, S. R. S.

    2017-06-01

    Recently, the proton exchange membrane fuel cell (PEMFC) has gained much attention to the technology of renewable energy due to its mechanically ideal and zero emission power source. PEMFC performance reflects from the surroundings such as temperature and pressure. This paper presents an analysis of the performance of the PEMFC by developing the mathematical thermodynamic modelling using Matlab/Simulink. Apart from that, the differential equation of the thermodynamic model of the PEMFC is used to explain the contribution of heat to the performance of the output voltage of the PEMFC. On the other hand, the partial pressure equation of the hydrogen is included in the PEMFC mathematical modeling to study the PEMFC voltage behaviour related to the input variable input hydrogen pressure. The efficiency of the model is 33.8% which calculated by applying the energy conversion device equations on the thermal efficiency. PEMFC’s voltage output performance is increased by increasing the hydrogen input pressure and temperature.

  2. Investigation of Equivalent Circuit for PEMFC Assessment

    International Nuclear Information System (INIS)

    Myong, Kwang Jae

    2011-01-01

    Chemical reactions occurring in a PEMFC are dominated by the physical conditions and interface properties, and the reactions are expressed in terms of impedance. The performance of a PEMFC can be simply diagnosed by examining the impedance because impedance characteristics can be expressed by an equivalent electrical circuit. In this study, the characteristics of a PEMFC are assessed using the AC impedance and various equivalent circuits such as a simple equivalent circuit, equivalent circuit with a CPE, equivalent circuit with two RCs, and equivalent circuit with two CPEs. It was found in this study that the characteristics of a PEMFC could be assessed using impedance and an equivalent circuit, and the accuracy was highest for an equivalent circuit with two CPEs

  3. Nonlinear Modeling of the PEMFC Based On NNARX Approach

    OpenAIRE

    Shan-Jen Cheng; Te-Jen Chang; Kuang-Hsiung Tan; Shou-Ling Kuo

    2015-01-01

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) is such a time-vary nonlinear dynamic system. The traditional linear modeling approach is hard to estimate structure correctly of PEMFC system. From this reason, this paper presents a nonlinear modeling of the PEMFC using Neural Network Auto-regressive model with eXogenous inputs (NNARX) approach. The multilayer perception (MLP) network is applied to evaluate the structure of the NNARX model of PEMFC. The validity and accurac...

  4. Modelling and validation of Proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Mohiuddin, A. K. M.; Basran, N.; Khan, A. A.

    2018-01-01

    This paper is the outcome of a small scale fuel cell project. Fuel cell is an electrochemical device that converts energy from chemical reaction to electrical work. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the different types of fuel cell, which is more efficient, having low operational temperature and fast start up capability results in high energy density. In this study, a mathematical model of 1.2 W PEMFC is developed and simulated using MATLAB software. This model describes the PEMFC behaviour under steady-state condition. This mathematical modeling of PEMFC determines the polarization curve, power generated, and the efficiency of the fuel cell. Simulation results were validated by comparing with experimental results obtained from the test of a single PEMFC with a 3 V motor. The performance of experimental PEMFC is little lower compared to simulated PEMFC, however both results were found in good agreement. Experiments on hydrogen flow rate also been conducted to obtain the amount of hydrogen consumed to produce electrical work on PEMFC.

  5. Improve the efficiency of PEMFC using neutron imaging

    International Nuclear Information System (INIS)

    Kim, Tae Joo; Shim, Chulmuu

    2010-01-01

    The water management is one of the most critical issues for PEMFC commercialization. In order to make a proper scheme for water management, the information of water distribution and behavior is very important. But the visualization is difficult due to metallic coverage. Recently, neutron imaging has joined the canon of diagnostic methods for fuel cell research and is applied worldwide with qualitative and quantitative results. In this investigation, we prepared 3-parallel serpentine single PEMFC. The active area is 250 mm 2 and channel size is 1 Χ 1 mm, respectively. Distribution and transport of water in an operating PEMFC were observed as functions of flow directions and differential pressures between anode and cathodes. This investigation was performed at BST-2, Nest. The collimation ratio is 600 and neutron fluence of BST-2 is 7.2 Χ 10 6 n/s, respectively. Neutron image was captured by A-Si detector with 1 sec expsosure time. The PEMFC has different performances for each differential pressure and flow directions. When the neutron images are compared with operating conditions, the distribution and behavior of water are different. Total water fraction is increased and then decreases as the current density increases. This situation is similar trend for the flow directions. It is shown that neutron imaging technique is powerful tool to visualize the PEMFC and the water distribution and behavior of an operating PEMFC helps improve the efficiency of PEMFC

  6. PEMFC modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C. [Federal University of Parana (UFPR), Curitiba, PR (Brazil). Dept. of Mechanical Engineering], E-mail: jvargas@demec.ufpr.br; Ordonez, J.C.; Martins, L.S. [Florida State University, Tallahassee, FL (United States). Center for Advanced Power Systems], Emails: ordonez@caps.fsu.edu, martins@caps.fsu.edu

    2009-07-01

    In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes. (author)

  7. Polyester synthesis for application in PEMFC type fuel cells; Sintese de poliester para aplicacao em celulas a combustivel do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.P.; Souza, D.R. de; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: raigenis@gmail.com

    2006-07-01

    The PEMFC (Proton Exchange Membrane Fuel Cell), along the SOFC (Solid Oxide Fuel Cell), is the most important technology, among the various types of fuels cell. The PEMFC shows a large versatility of applications, both for stationary and mobile use. However the PEMFC presents high manufacture cost, directly impacting in the cost of the produced energy. This work contemplates the previews sulfonation of phtalic acid and its subsequent polymerization with glycerol, using as catalytic tin dibutyl-dilaurate. The obtained material has been characterized by DSC, TGA, FTIR, MEV, DRX and XRF. The gotten results indicated that phtalic acid was sulfonated and the increase of the sulfonation degree significantly increased the crystallinity of the sulfonated ftalico acid. Furthermore, the polymer produced from the sulfonated monomer presented adequate thermal resistance and a high content of conducting groups, necessary conditions for application as electrolyte in PEMFC. All these characteristics, particularly the low cost of the reagents and the ease of production process, make the sulfonated polyester membrane a promising candidate as fuel cell electrolyte. (author)

  8. Research progress of aluminium alloy endplates for PEMFCs

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yu.; Hou, Junbo [Fuel Cell system and Engineering Laboratory, Dalian Institute of Chemical and Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Hou, Ming; Yan, Xiqiang; Luo, Xiaokuan; Shao, Zhigang; Yi, Baolian [Fuel Cell system and Engineering Laboratory, Dalian Institute of Chemical and Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2007-04-15

    The endplate is a crucial component in a proton exchange membrane fuel cell (PEMFC) stack. It can provide the necessary rigidity and strength for the stack. An aluminium alloy is one of the ideal materials for PEMFC endplates because of its low density and high rigidity. But it does not meet the requirements of corrosion resistance and electrical insulation in PEMFC environments. In this work, methods of sealing treatments and the conditions of aluminium alloy anodization were investigated. Corrosion resistances of the samples prepared by different technologies were evaluated in simulated PEMFC environments. The results showed that the corrosion resistance of the samples sealed by epoxy resin was greatly improved compared with those sealed in boiling water, and the samples anodized at a constant current density performed better than those anodized at a constant voltage. By insulation measurements, all of the samples showed good electrical insulation. The aluminium alloy endplate anodized at a constant current density and sealed with thermosetting bisphenol-A epoxy resin exhibited promising potential for practical applications by assembling it in a PEMFC stack and applying a life test. (author)

  9. Membranes optimization of the basis of S-peek with different degrees of sulfonation for PEMFC; Otimizacao de membranas a base de S-peek com diferentes graus de sulfonacao para PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, E.B.; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S.; Carvalho, L.F.V. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencia dos Materiais

    2008-07-01

    With the growing concern emission of polluting gases in the atmosphere and search for alternative sources of clean energy that can meet the future shortage of oil, the fuel cells have become the target of scientific research in everyone. Among the various types of fuel cells includes the PEMFC (Polymer exchange membrane fuel cell), in the case of a device with high efficiency, without emission of pollutants. This work was to produce membranes and optimizing the basis of S-PEEK (poly-ether-ether-sulfonate) with varying degrees of sulfonation to be applied as electrolytes in fuel cells to the type PEMFC. The membranes were characterized chemically, by thermal analysis, and electrochemistry. (author)

  10. Biomass-fuelled PEMFC systems: Evaluation of two conversion paths relevant for different raw materials

    International Nuclear Information System (INIS)

    Guan, Tingting; Chutichai, Bhawasut; Alvfors, Per; Arpornwichanop, Amornchai

    2015-01-01

    Highlights: • Anaerobic digestion and gasification are viable biomass conversion technologies. • GF-PEMFC system yields a 20% electric efficiency and 57% thermal efficiency. • AD-PEMFC system has a 9% electric efficiency and 13% thermal efficiency. • AD-PEMFC system has an efficient land-use. • GF-PEMFC system has a high CO_2 emissions offset factor. - Abstract: Biomass-fuelled polymer electrolyte membrane fuel cells (PEMFCs) offer a solution for replacing fossil fuel with hydrogen production. This paper uses simulation methods for investigating biomass-fuelled PEMFCs for different raw materials and conversion paths. For liquid and solid biomass, anaerobic digestion (AD) and gasification (GF), respectively, are relatively viable and developed conversion technologies. Therefore, the AD-PEMFC system and the GF-PEMFC system are simulated for residential applications in order to evaluate the performance of the biomass-fuelled PEMFC systems. The results of the evaluation show that renewable hydrogen-rich gas from manure or forest residues is usable for the PEMFCs and makes the fuel cell stack work in a stable manner. For 100 kWe generation, the GF-PEMFC system yields an excellent technical performance with a 20% electric efficiency and 57% thermal efficiency, whereas the AD-PEMFC system only has an 9% electric efficiency and 13% thermal efficiency due to the low efficiency of the anaerobic digester (AD) and the high internal heat consumption of the AD and the steam reformer (SR). Additionally, in this study, the environmental performances of the AD-PEMFC and the GF-PEMFC in terms of CO_2 emission offset and land-use efficiency are discussed.

  11. Modeling and control of PEMFC based on least squares support vector machines

    International Nuclear Information System (INIS)

    Li Xi; Cao Guangyi; Zhu Xinjian

    2006-01-01

    The proton exchange membrane fuel cell (PEMFC) is one of the most important power supplies. The operating temperature of the stack is an important controlled variable, which impacts the performance of the PEMFC. In order to improve the generating performance of the PEMFC, prolong its life and guarantee safety, credibility and low cost of the PEMFC system, it must be controlled efficiently. A nonlinear predictive control algorithm based on a least squares support vector machine (LS-SVM) model is presented for a family of complex systems with severe nonlinearity, such as the PEMFC, in this paper. The nonlinear off line model of the PEMFC is built by a LS-SVM model with radial basis function (RBF) kernel so as to implement nonlinear predictive control of the plant. During PEMFC operation, the off line model is linearized at each sampling instant, and the generalized predictive control (GPC) algorithm is applied to the predictive control of the plant. Experimental results demonstrate the effectiveness and advantages of this approach

  12. PEMFC for aeronautic applications: A review on the durability aspects

    Science.gov (United States)

    Dyantyi, Noluntu; Parsons, Adrian; Sita, Cordellia; Pasupathi, Sivakumar

    2017-11-01

    Proton exchange membrane fuel cells (PEMFC) not only offer more efficient electrical energy conversion, relative to on-ground/backup turbines but generate by-products useful in aircraft such as heat for ice prevention, deoxygenated air for fire retardation and drinkable water for use on-board. Consequently, several projects (e.g. DLR-H2 Antares and RAPID2000) have successfully tested PEMFC-powered auxiliary unit (APU) for manned/unmanned aircraft. Despite the progress from flying PEMFC-powered small aircraft with 20 kW power output as high as 1 000 m at 100 km/h to 33 kW at 2 558 m, 176 km/h [1, 2, 3], durability and reliability remain key challenges. This review reports on the inadequate understanding of behaviour of PEMFC under aeronautic conditions and the lack of predictive methods conducive for aircraft that provide real-time information on the State of Health of PEMFCs. -To minimize performance loss due to high altitude and inclination by adjusting cathode stoichiometric ratio. -To improve quality of oxygen-depleted air by controlling operating temperature and stoichiometric ratio. -Need to devise real time prediction methods conducive for determining PEMFC SoH in aircraft.

  13. Reclaim/recycle of Pt/C catalysts for PEMFC

    International Nuclear Information System (INIS)

    Zhao, Jishi; He, Xiangming; Tian, Jianhua; Wan, Chunrong; Jiang, Changyin

    2007-01-01

    Platinum was reclaimed from Pt/C catalysts of the PEMFC by drying the degraded Pt/C catalysts at 80 o C for 3 h, followed by sintering at 600 o C for 6 h, dissolution by aqua fortis, purification with hydrochloric acid, reduction and filtration, successively. Pt/C catalysts were prepared again from the reclaimed Pt by two proposed processes, e.g., pH value control process and mass control process. The fuel cell with recycled catalysts presented a power density of over 0.18 W cm -2 . The reclaiming of Pt/C catalysts is a potential way for recycling Pt for PEMFC, reducing the cost of PEMFC

  14. Mathematical model of a PEMFC using a PBI membrane

    International Nuclear Information System (INIS)

    Cheddie, Denver; Munroe, Norman

    2006-01-01

    Proton exchange membrane fuel cells (PEMFC) operating with Nafion[reg] membranes have encountered numerous problems associated with water management and CO poisoning because of their low temperature of operation. Alternative high temperature membranes have been investigated, one such membrane being polybenzimidazole (PBI). This paper presents a one dimensional mathematical model, which predicts the polarization performance of a PEMFC using a PBI membrane. Peak power densities in the same order as Nafion[reg] are predicted. Results indicate that the greatest scope for improving PBI PEMFC performance is increasing the membrane conductivity and improving the catalyst performance as it interfaces with the PBI membrane

  15. Thermal management issues in a PEMFC stack - A brief review of current status

    International Nuclear Information System (INIS)

    Kandlikar, Satish G.; Lu Zijie

    2009-01-01

    Understanding the thermal effects is critical in optimizing the performance and durability of proton exchange membrane fuel cells (PEMFCs). A PEMFC produces a similar amount of waste heat to its electric power output and tolerates only a small deviation in temperature from its design point. The balance between the heat production and its removal determines the operating temperature of a PEMFC. These stringent thermal requirements present a significant heat transfer challenge. In this work, the fundamental heat transfer mechanisms at PEMFC component level (including polymer electrolyte, catalyst layers, gas diffusion media and bipolar plates) are briefly reviewed. The current status of PEMFC cooling technology is also reviewed and research needs are identified

  16. Evaluation of reciprocating electromagnetic air pumping for portable PEMFC

    International Nuclear Information System (INIS)

    Kwon, Kilsung; Kang, Ho; Kang, Seongwon; Kim, Daejoong

    2013-01-01

    In this paper, we present a proton exchange membrane fuel cell (PEMFC) integrated with an electromagnetic (EM) air pump. The EM air pump provides the PEMFC with air by reciprocating motions of the permanent magnet attached to a flexible membrane. We performed a parametric study to decide the optimal dimensions of the reciprocating EM air pump. The effects of various operating parameters on the EM air pump were investigated with the root-mean-square (RMS) flow rate and current. A core with a higher relative permeability shows better performance. The RMS current linearly increases with the applied voltage and shows no dependence on the frequency. The RMS flow rate also increases with the voltage. The RMS flow rate per power consumption is highest at the frequency around 20 Hz and decreases as the applied voltage increases. When the reciprocating EM air pump was used to supply air to the portable PEMFC, it was found that the power density of the PEMFC increases with the applied voltage and shows the highest performance at the frequency of 10 Hz. We compared the performance of the PEMFC between the flow meter and the EM air pump used as an air supplier. About 81% of the output power using the flow meter was obtained when the EM air pump is operated at the applied voltage of 5 V. The parasitic power ratio reaches at its minimum value about 0.1 with an EM applied voltage of 0.25V. (paper)

  17. Effects of cathode channel size and operating conditions on the performance of air-blowing PEMFCs

    International Nuclear Information System (INIS)

    Kim, Bosung; Lee, Yongtaek; Woo, Ahyoung; Kim, Yongchan

    2013-01-01

    Highlights: • Effect of cathode channel size on the air-blowing PEMFC is analyzed. • Performance and EIS tests of air-blowing PEMFCs are conducted. • Test conditions include the operating temperature, fan voltage, and anode humidity. • Flooding is a limiting factor for decreasing channel size at low temperature. • Water management is investigated by analyzing ohmic resistance. - Abstract: Air-blowing proton exchange membrane fuel cells (PEMFCs) have been developed as a potential new power source for portable electronic devices. However, air-blowing PEMFCs show lower performance than compressed-air PEMFCs because of their adverse operating conditions. In this study, the effects of the cathode channel size and operating conditions on the performance of the air-blowing PEMFC were analyzed. At the normal operating temperature, the performance of the air-blowing PEMFC improved with the decrease in the cathode channel size. However, at a low operating temperature and low fan voltage, massive flooding limits the decrease in the cathode channel size. In addition, water management in the air-blowing PEMFC was investigated by analyzing ohmic resistance. The transition current density between the humidification and the flooding region decreased with decreasing cathode channel size and operating temperature

  18. Power sources involving ~ 300W PEMFC fuel cell stacks cooled by different media

    Directory of Open Access Journals (Sweden)

    Dudek Magdalena

    2017-01-01

    Full Text Available Two constructions of ~300W PEMFC stacks, cooled by different media, were analysed. An open-cathode ~300W PEMFC stack cooled by air (Horizon, Singapore and a PEMFC F-42 stack cooled by a liquid medium (Schunk, Germany were chosen for all of the investigations described in this paper. The potential for the design and construction of power sources involving fuel cells, as well as of a hybrid system (fuel cell-lithium battery for mobile and stationary applications, is presented and discussed. The impact of certain experimental parameters on PEMFC stack performance is analysed and discussed.

  19. Compact open cathode feed system for PEMFCs

    International Nuclear Information System (INIS)

    Ling, C.Y.; Cao, H.; Chen, Y.; Han, M.; Birgersson, E.

    2016-01-01

    Highlights: • Two different modes of feeding air into an open cathode PEMFC stack were studied. • Drawing air, as opposed to blowing air, into the stack results in more uniform air velocities entering the stack. • The uniform inlet velocities help maintain a more even temperature distribution field. • A 16% increase in power output is observed by drawing air into the stack. - Abstract: The open cathode design is commonly adopted for small sized proton exchange membrane fuel cells (PEMFCs) as it allows for smaller footprint and thus, higher power density. Axial fans are typically used to supply oxygen in these PEMFC systems. Apart from controlling stoichiometry, they also play a critical role in regulating internal temperature. This suggests that its location could have significant impact on fuel cell performance. In this work, the location of the fan is varied from the front to the rear in order to blow air or draw air into the stack respectively. The latter configuration reduces the non-uniformity in temperature and velocity by around 2 and 4 times respectively, resulting in a 16% increase in overall stack performance.

  20. Multi-dimensional modeling of CO poisoning effects on proton exchange membrane fuel cells (PEMFCs)

    International Nuclear Information System (INIS)

    Ju, Hyun Chul; Lee, Kwan Soo; Um, Suk Kee

    2008-01-01

    Carbon monoxide (CO), which is preferentially absorbed on the platinum catalyst layer of a proton exchange membrane fuel cell (PEMFC), is extremely detrimental to cell performance. Essentially, the carbon monoxide absorption diminishes the cell's performance by blocking and reducing the number of catalyst sites available for the hydrogen oxidation reaction. In order to obtain a full understanding of CO poisoning characteristics and remediate CO-poisoned PEMFCs, a CO poisoning numerical model is developed and incorporated into a fully three-dimensional electrochemical and transport coupled PEMFC model. By performing CFD numerical simulations, this paper clearly demonstrates the CO poisoning mechanisms and characteristics of PEMFCs. The predictive capability for CO poisoning effects enables us to find major contributors to CO tolerance in a PEMFC and thus successfully integrate CO-resistant fuel cell systems

  1. Degradations analysis and aging modeling for health assessment and prognostics of PEMFC

    International Nuclear Information System (INIS)

    Jouin, Marine; Gouriveau, Rafael; Hissel, Daniel; Péra, Marie-Cécile; Zerhouni, Noureddine

    2016-01-01

    Applying prognostics to Proton Exchange Membrane Fuel Cell (PEMFC) stacks is a good solution to help taking actions extending their lifetime. However, it requires a great understanding of the degradation mechanisms and failures occurring within the stack. This task is not simple when applied to a PEMFC due to the different levels (stack - cells - components), the different scales and the multiple causes that lead to degradation. To overcome this problem, this work proposes a methodology dedicated to the setting of a framework and a modeling of the aging for prognostics. This methodology is based on a deep literature review and degradation analyses of PEMFC stacks. This analysis allows defining a proper vocabulary dedicated to PEMFC's prognostics and health management and a clear limited framework to perform prognostics. Then the degradations review is used to select critical components within the stack, and to define their critical failure mechanisms thanks the proposal of new fault trees. The impact of these critical components and mechanisms on the power loss during aging is included to the model for prognostics. This model is finally validated on four datasets with different mission profiles both for health assessment and prognostics. - Highlights: • A proper framework to perform PHM, particularly prognostics, of PEMFC is proposed. • A degradation analysis is performed. • A completely new model of PEMFC degradation is proposed. • SOH estimation is performed with very high coefficients of determination.

  2. Evaluation of aircraft crash at Laboratorio de Geracao Nucleo-Eletrica (LABGENE) located at Centro Experimental ARAMAR

    International Nuclear Information System (INIS)

    Hirata, Daniel M.; Ramos, Monique M.B.

    2013-01-01

    One of the human-induced external hazards to be considered in a Level 1 Probabilistic Safety Assessment for a nuclear plant is the aircraft crash, so it's necessary to have the estimative of the frequency of this hazard. In this paper is obtained the annual frequency of aircraft crash at the Laboratorio de Geracao Nucleo-Eletrica (LABGENE) located at the Centro Experimental ARAMAR (CEA).The calculation of this frequency was based on the method recommended in the Standard Review Plan Section 3.5.1.6 considering the airports, training camps and airways located in CEA's region. The estimated value for the aircraft crash frequency obtained is in accordance with the acceptance criteria established in the Standard Review plan Section 3.5.1.6. (author)

  3. Mass transport in a PEMFC fuel battery using combinations of monopolar plates and reaction-diffusion medium; Transporte de masa en una pila a combustible tipo PEMFC utilizando combinaciones de platos monopolares y medios de difusion de reactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rosas Paleta, M. G. Araceli [Benemerita Universidad Autonoma de Puebla, Puebla, Puebla (Mexico); Bautista Rodriguez, C. Moises [Alter-Energias Puebla, Puebla (Mexico)] email: celso.bautista@thyssenkrupp.com; Rivera Marquez, J. Antonio; Tepale Ochoa, Nancy [Benemerita Universidad Autonoma de Puebla, Puebla, Puebla (Mexico)

    2009-09-15

    sitios activos del electrodo. Los gases reactivos suministrados a una PEMFC se distribuyen sobre la capa de difusion de los electrodos por medio de los canales de las placas polares, posteriormente difunden hacia la capa activa donde se llevan a cabo las semi-reacciones. Otro aspecto importante es la presencia de las moleculas de agua, producto de la reaccion, que al acumularse cubren la porosidad de los electrodos implicando la reduccion del flujo de los reactivos, incluso a altos valores de densidad de corriente se combina con los fenomenos de difusion involucrados, ocasionando; el cese total en el funcionamiento de la PEMFC. Los parametros criticos para los fenomenos de transporte son la porosidad, el diametro del poro en la capa de difusion y las caracteristicas de distribucion de reactivos. El presente trabajo comprende un diseno experimental entre dos medios de distribucion y dos medios de difusion de gases reactivos en una PEMFC, implicando tres casos de estudio. Los resultados obtenidos muestran interacciones notablemente significativas entre el diametro de poro, el tipo de capa de difusion aplicada y el tipo de distribuidor aplicado. La combinacion en el segundo caso reduce significativamente las resistencias ohmicas y moderadamente las resistencias por difusion mientras la combinacion del caso tres incrementa notablemente las resistencias ohmicas sin embargo reducen las resistencias por difusion de forma importante.

  4. Parameter identification of PEMFC model based on hybrid adaptive differential evolution algorithm

    International Nuclear Information System (INIS)

    Sun, Zhe; Wang, Ning; Bi, Yunrui; Srinivasan, Dipti

    2015-01-01

    In this paper, a HADE (hybrid adaptive differential evolution) algorithm is proposed for the identification problem of PEMFC (proton exchange membrane fuel cell). Inspired by biological genetic strategy, a novel adaptive scaling factor and a dynamic crossover probability are presented to improve the adaptive and dynamic performance of differential evolution algorithm. Moreover, two kinds of neighborhood search operations based on the bee colony foraging mechanism are introduced for enhancing local search efficiency. Through testing the benchmark functions, the proposed algorithm exhibits better performance in convergent accuracy and speed. Finally, the HADE algorithm is applied to identify the nonlinear parameters of PEMFC stack model. Through experimental comparison with other identified methods, the PEMFC model based on the HADE algorithm shows better performance. - Highlights: • We propose a hybrid adaptive differential evolution algorithm (HADE). • The search efficiency is enhanced in low and high dimension search space. • The effectiveness is confirmed by testing benchmark functions. • The identification of the PEMFC model is conducted by adopting HADE.

  5. Evaluation of aircraft crash at Laboratorio de Geracao Nucleo-Eletrica (LABGENE) located at Centro Experimental ARAMAR

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Daniel M.; Ramos, Monique M.B., E-mail: daniel.hirata@ctmsp.mar.mil.br, E-mail: monique@ctmsp.mar.mil.br [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil)

    2013-07-01

    One of the human-induced external hazards to be considered in a Level 1 Probabilistic Safety Assessment for a nuclear plant is the aircraft crash, so it's necessary to have the estimative of the frequency of this hazard. In this paper is obtained the annual frequency of aircraft crash at the Laboratorio de Geracao Nucleo-Eletrica (LABGENE) located at the Centro Experimental ARAMAR (CEA).The calculation of this frequency was based on the method recommended in the Standard Review Plan Section 3.5.1.6 considering the airports, training camps and airways located in CEA's region. The estimated value for the aircraft crash frequency obtained is in accordance with the acceptance criteria established in the Standard Review plan Section 3.5.1.6. (author)

  6. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  7. Performance analysis of an integrated biomass gasification and PEMFC (proton exchange membrane fuel cell) system: Hydrogen and power generation

    International Nuclear Information System (INIS)

    Chutichai, Bhawasut; Authayanun, Suthida; Assabumrungrat, Suttichai; Arpornwichanop, Amornchai

    2013-01-01

    The PEMFC (proton exchange membrane fuel cell) is expected to play a significant role in next-generation energy systems. Because most hydrogen that is used as a fuel for PEMFCs is derived from the reforming of natural gas, the use of renewable energy sources such as biomass to produce this hydrogen offers a promising alternative. This study is focused on the performance analysis of an integrated biomass gasification and PEMFC system. The combined heat and power generation output of this integrated system is designed for residential applications, taking into account thermal and electrical demands. A flowsheet model of the integrated PEMFC system is developed and employed to analyze its performance with respect to various key operating parameters. A purification process consisting of a water–gas shift reactor and a preferential oxidation reactor is also necessary in order to reduce the concentration of CO in the synthesis gas to below 10 ppm for subsequent use in the PEMFC. The effect of load level on the performance of the PEMFC system is investigated. Based on an electrical load of 5 kW, it is found that the electrical efficiency of the PEMFC integrated system is 22%, and, when waste heat recovery is considered, the total efficiency of the PEMFC system is 51%. - Highlights: • Performance of a biomass gasification and PEMFC integrated system is analyzed. • A flowsheet model of the PEMFC integrated system is developed. • Effect of biomass sources and key parameters on hydrogen and power generation is presented. • The PEMFC integrated system is designed for small-scale power demand. • Effect of load changes on the performance of PEMFC is investigated

  8. Parametric investigation to enhance the performance of a PBI-based high-temperature PEMFC

    International Nuclear Information System (INIS)

    Ferng, Y.M.; Su, A.; Hou, J.

    2014-01-01

    Highlights: • A in-house PBI PEMFC is prepared by the Fuel Cell Center of Yuan Ze University. • Parametric effects to enhance the PBI based PEMFC performance are investigated. • Experiments and simulations are performed to study these parametric effects. • Cell performance is enhanced with the lower PBI loading and higher temperature. • Thinner CL thickness and higher acid doping benefit to the cell performance also. - Abstract: With the advantages of simpler heat and water management, lower CO poisoning, and higher reaction kinetics, the high-temperature polybenzimidazole (PBI)-based proton exchange membrane fuel cell (PEMFC) can be considered as one of the commercialized energy generators in the near future. This paper experimentally and analytically investigates different design and operating parameters to enhance the performance of a PBI-based PEMFC, an in-house cell prepared in the Fuel Cell Center of Yuan Ze University. These parameters studied include PBI loading, operating temperature, gas flowrate, electrode thickness and porosity, and acid doping level. Experiments are performed to study the effects of PBI loading, operating temperature, and gas flowrate on the cell performance. Validated against the measured data of polarization and power curves, a simplified two-dimensional model for this PBI-based PEMFC is also developed to help the experiments to investigate other parameters. Based on the experimental data and the model predictions, the cell performance can be enhanced as the PBI loading is reduced, the operating temperature is elevated. Thinner electrode thickness, smaller porosity, and higher acid doping level are also predicted to benefit to the performance of the PBI-based PEMFC

  9. A PEMFC hybrid electric vehicle real time control system

    Science.gov (United States)

    Sun, Hongqiao

    In recent years, environmental friendly technologies and alternative energy solutions have drawn a lot of public attentions due to global energy crisis and pollution issues. Fuel cell (FC), a technology invented almost at the same time as the internal combustion (IC) engine, is now the focus of the automotive industry again. The fuel cell vehicle (FCV) has zero emission and its efficiency is significantly higher than the conventional IC engine power vehicles. Among a variety of FCV technologies, proton exchange membrane (PEM) FC vehicle appears to be far more attractive and mature. The prototype PEMFC vehicle has been developed and demonstrated to the public by nearly all the major automotive manufacturers in recent years. However, to the interest of the public research, publications and documentations on the PEMFC vehicle technology are rarely available due to its proprietary nature, which essentially makes it a secured technology. This dissertation demonstrates a real world application of a PEMFC hybrid electric vehicle. Through presenting the vehicle design concept, developing the real time control system and generating generic operation principles, this dissertation targets at establishing the public knowledge base on this new technology. A complete PEMFC hybrid electric vehicle design, including vehicle components layout, process flow diagram, real time control system architecture, subsystem structures and control algorithms, is presented in order to help understand the whole vehicle system. The design concept is validated through the vehicle demonstration. Generic operating principles are established along with the validation process, which helps populate this emerging technology. Thereafter, further improvements and future research directions are discussed.

  10. CO tolerance effects of tungsten-based PEMFC anodes

    International Nuclear Information System (INIS)

    Pereira, Luis Gustavo S.; Santos, Fatima R. dos; Pereira, Maristela E.; Paganin, Valdecir A.; Ticianelli, Edson A.

    2006-01-01

    The performance of proton exchange membrane fuel cells (PEMFC) fed with CO-contaminated hydrogen was investigated for anodes with PtWO x /C and phosphotungstic acid (PTA) impregnated Pt/C electrocatalysts. A quite high performance was achieved for the PEMFC fed with H 2 + 100 ppm CO with anodes containing 0.4 mg PtWO x cm -2 and also for those with 0.4 mg Pt cm -2 impregnated with ca. 1 mg PTA cm -2 . A decay of the single cell performance with time is observed, and this was attributed to an increase of the membrane resistance due to the polymer degradation promoted by the crossover of the tungsten species throughout the membrane

  11. Nanostructured TiO2 Doped with Nb as a Novel Support for PEMFC

    Directory of Open Access Journals (Sweden)

    Edgar Valenzuela

    2013-01-01

    Full Text Available Nowadays, one of the major issues of the PEMFC concerns the durability. Historically, carbon has been used as a catalyst support in PEMFC; nevertheless, under the environmental conditions of the cell, the carbon is oxidized, leaving the catalyst unsupported. In order to increase the stability and durability of the catalyst in the PEMFC, a novel nanostructured metallic oxide support is proposed. In this work, TiO2 was doped with Nb to obtain a material that combines chemical stability, high surface area, and an adequate electronic conductivity in order to be a successful catalyst support candidate for long-term PEMFC applications. The TiO2-Nb nanostructured catalyst support was physically and electrochemically characterized. According to the results, the TiO2-Nb offers high surface area and good particle dispersion; also, the electrochemical activity and stability of the support were evaluated under high potential conditions, where the TiO2-Nb proved to be much more stable than carbon.

  12. Effect of different fuel options on performance of high-temperature PEMFC (proton exchange membrane fuel cell) systems

    International Nuclear Information System (INIS)

    Authayanun, Suthida; Saebea, Dang; Patcharavorachot, Yaneeporn; Arpornwichanop, Amornchai

    2014-01-01

    High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have received substantial attention due to their high CO (carbon monoxide) tolerance and simplified water management. The hydrogen and CO fractions affect the HT-PEMFC performance and different fuel sources for hydrogen production result in different product gas compositions. Therefore, the aim of this study is to investigate the theoretical performance of HT-PEMFCs fueled by the reformate gas derived from various fuel options (i.e., methane, methanol, ethanol, and glycerol). Effects of fuel types and CO poisoning on the HT-PEMFC performance are analyzed. Furthermore, the necessity of a water-gas shift (WGS) reactor as a CO removal unit for pretreating the reformate gas is investigated for each fuel type. The methane steam reforming shows the highest possibility of CO formation, whereas the methanol steam reforming produces the lowest quantity of CO in the reformate gas. The methane fuel processing gives the maximum fraction of hydrogen (≈0.79) when the WGS reactor is included. The most suitable fuel is the one with the lowest CO poisoning effect and the maximum fuel cell performance. It is found that the HT-PEMFC system fueled by methanol without the WGS reactor and methane with WGS reactor shows the highest system efficiency (≈50%). - Highlights: • Performance of HT-PEMFC run on different fuel options is theoretically investigated. • Glycerol, methanol, ethanol and methane are hydrogen sources for the HT-PEMFC system. • Effect of CO poisoning on the HT-PEMFC performance is taken into account. • The suitable fuel for HT-PEMFC system is identified regarding the system efficiency

  13. An investigation of coated aluminium bipolar plates for PEMFC

    International Nuclear Information System (INIS)

    Lin, Chien-Hung; Tsai, Sung-Ying

    2012-01-01

    Highlights: ► Coated aluminium bipolar plates demonstrate the hydrophobic property than the raw material. ► The corrosion behaviour of bipolar plate decreases the PEMFC performance severely. ► These PEMFCs are measured by current–voltage (I–V) curve test. ► The oxide film increases the interfacial contact resistance. -- Abstract: The performance of Al-alloy bipolar plates for the PEMFC (proton exchange membrane fuel cell) system is investigated in this paper. The metallic bipolar plates are modified with a Ni–P coating. The performance of the Al-alloy bipolar plates is evaluated by the coating structure, corrosion resistance, contact angle and single cell performance. The results indicate that the coated aluminium bipolar plates demonstrate hydrophobic and anti-corrosive properties. The hydrophobic property increases the contact angle on the surface from 46.08° to 80.51°. Meanwhile, the corrosion rate of the Ni–P coating can be over 1 order of magnitude lower than that of the substrate. Hence, the substrate with the coating maintains superior performance under the long term test. The present study proves that both the hydrophobicity and corrosion resistance significantly affect the metallic bipolar plate.

  14. Investigation for Water Propagation at PEMFC with Single Channel by Neutron Imaging Technique

    International Nuclear Information System (INIS)

    Kim, Tae Joo; Sim, Cheul Muu; Kim, Jong Rok; Kim, Moo Hwan

    2008-01-01

    Effective water management increases performance and durability of the Polymer Electrolyte Membrane Fuel cell(PEMFC). The membrane in PEMFC must be sufficiently hydrated because its conductivity relies primarily on the humidity state of the membrane. Since water is generated as a by-product when the fuel cell is generating power, this water source can be said to be a 'disturbance' to any water management system, which is trying to maintain proper humidity level without flooding. Since water is generated throughout the active area, the downstream area can be flooded even when the upstream area is under-saturated. This creates a challenging environment for water management, which adversely affects the efficiency and reliability in the operation of the PEMFC. Although there are many researches for the water management, their interests are limited on the performance. However, the fundamental information of water propagation characteristics is needed to make a scheme for water management. In this study, we used specially designed PEMFC with only single channel, and the water propagation was investigated according to the channel location by neutron imaging technique

  15. An Energy Dense-AI-NaBH4-PEMFC Based Power Generator for Unmanned Undersea Vehicles

    Science.gov (United States)

    2016-03-01

    From- To) 03/01/2016 Final 01/28/2013-12/31/2015 4. TITLE AND SUBTITLE Sa. CONTRACT NUMBER An Energy-Dense AI-NaBH4- PEMFC Based Power Generator for...combination of polymer electrolyte membrane fuel cell ( PEMFC ) with a compact hydrogen generator util izing AI-NaBH4 composite fuel. The conditions...ANSI Std. Z39.18 FLORIDA SOLAR ENERGY CENTER. Crl’nrmg EnPrgy lnrll’pendrnr£’ An Energy-Dense Al-NaBH4- PEMFC Based Power Generator for Unmanned

  16. Durable electrocatalytic-activity of Pt-Au/C cathode in PEMFCs.

    Science.gov (United States)

    Selvaganesh, S Vinod; Selvarani, G; Sridhar, P; Pitchumani, S; Shukla, A K

    2011-07-21

    Longevity remains as one of the central issues in the successful commercialization of polymer electrolyte membrane fuel cells (PEMFCs) and primarily hinges on the durability of the cathode. Incorporation of gold (Au) to platinum (Pt) is known to ameliorate both the electrocatalytic activity and stability of cathode in relation to pristine Pt-cathodes that are currently being used in PEMFCs. In this study, an accelerated stress test (AST) is conducted to simulate prolonged fuel-cell operating conditions by potential cycling the carbon-supported Pt-Au (Pt-Au/C) cathode. The loss in performance of PEMFC with Pt-Au/C cathode is found to be ∼10% after 7000 accelerated potential-cycles as against ∼60% for Pt/C cathode under similar conditions. These data are in conformity with the electrochemical surface-area values. PEMFC with Pt-Au/C cathode can withstand >10,000 potential cycles with very little effect on its performance. X-ray diffraction and transmission electron microscopy studies on the catalyst before and after AST suggest that incorporating Au with Pt helps mitigate aggregation of Pt particles during prolonged fuel-cell operations while X-ray photoelectron spectroscopy reflects that the metallic nature of Pt is retained in the Pt-Au catalyst during AST in comparison to Pt/C that shows a major portion of Pt to be present as oxidic platinum. Field-emission scanning electron microscopy conducted on the membrane electrode assembly before and after AST suggests that incorporating Au with Pt helps mitigating deformations in the catalyst layer. This journal is © the Owner Societies 2011

  17. The mass balance of a Proton Exchange Membrane Fuel Cell (PEMFC)

    International Nuclear Information System (INIS)

    Miloud, S.; Kamaruzzaman Sopian; Wan Ramli Wan Daud

    2006-01-01

    A Proton Exchange Membrane Fuel Cell (PEMFC), operating at low temperature uses a simple chemical process to combine hydrogen and oxygen into water, producing electric current and heat during the electrochemical reaction. This work concern on the theoretical consideration of the mass balance has been evaluated to predict the mass flow rate of the both gases (hydrogen/oxygen), the water mass balance, and the heat transfer in order to design a single cell PEMFC stack with a better flow field distributor on the performance of Polymer Electrolyte membrane fuel cells

  18. NOVEL RU-NI-S ELECTRODE CATALYST FOR PEMFC

    Science.gov (United States)

    The expected results from this project include: a new formula and preparation procedures for Ru-Ni-S catalyst; demonstration of CO and S tolerance of the new catalyst; a small size PEMFC with Ru-Ni-S catalyst and good performance; an...

  19. Systematic characterization of HT PEMFCs containing PBI/H{sub 3}PO{sub 4} systems. Thermodynamic analysis and experimental investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bandlamudi, George Chakravarthy

    2011-07-01

    High temperature PEMFCs (HT PEMFCs), operating at 120 C - 200 C are rather new and offer tremendous advantages. For instance fuel cells operating at > 100 C reduce issues related to water management substantially. Circulating excess heat energy from such fuel cells into other system processes where heat is needed would be much more practical (due to higher {delta}T) compared to the standard LT PEMFCs where the produced heat has less than 90 C (lower {delta}T). Higher tolerance to fuel impurities such as CO, by these HT PEMFCs has made them very practical for many applications. Although PBI/H{sub 3}PO{sub 4} based membranes have been explored for use in PEMFCs from the early 1990s, only recently PEMEAS (currently BASF) has marketed them as commercially available MEAs. Besides, some companies such as Sartorius (currently Elcomax) and Fuma Tech of Germany, Danish Power Systems of Denmark are offering HT-MEAs on a commercial basis. Although some issues remain, such as development of durable and low cost catalyst and catalyst support materials, acid management, the rapid development of membranes and MEAs has been motivated by a huge demand from many a market. Recently, DLR in Germany has tested its pilot airplane (Antares) fully operated with a HT PEMFC stack (with on-board H{sub 2} bottle). ClearEdge Power in Portland, USA has been developing systems based on HT PEMFC technology to be deployed in the US as well as in South Korean households. Many more companies are increasingly interested in this technology due to the many fold advantages it has to offer. This work is aimed at elucidating this HT PEMFC technology, in terms of giving an in-depth view of what it means to operate a HT PEMFC. (orig.)

  20. CO tolerance of PdPt/C and PdPtRu/C anodes for PEMFC

    International Nuclear Information System (INIS)

    Garcia, Amanda C.; Paganin, Valdecir A.; Ticianelli, Edson A.

    2008-01-01

    The performance of H 2 /O 2 proton exchange membrane fuel cells (PEMFCs) fed with CO-contaminated hydrogen was investigated for anodes with PdPt/C and PdPtRu/C electrocatalysts. The physicochemical properties of the catalysts were characterized by energy dispersive X-ray (EDX) analyses, X-ray diffraction (XRD) and 'in situ' X-ray absorption near edge structure (XANES). Experiments were conducted in electrochemical half and single cells by cyclic voltammetry (CV) and I-V polarization measurements, while DEMS was employed to verify the formation of CO 2 at the PEMFC anode outlet. A quite high performance was achieved for the PEMFC fed with H 2 + 100 ppm CO with the PdPt/C and PdPtRu/C anodes containing 0.4 mg metal cm -2 , with the cell presenting potential losses below 200 mV at 1 A cm -2 , with respect to the system fed with pure H 2 . For the PdPt/C catalysts no CO 2 formation was seen at the PEMFC anode outlet, indicating that the CO tolerance is improved due to the existence of more free surface sites for H 2 electrooxidation, probably due to a lower Pd-CO interaction compared to pure Pd or Pt. For PdPtRu/C the CO tolerance may also have a contribution from the bifunctional mechanism, as shown by the presence of CO 2 in the PEMFC anode outlet

  1. Estudo da potencialidade dos processos oxidativos avançados na remediação de águas contaminadas por microcistina - LR.

    OpenAIRE

    Jacobs, Loraine Cristina do Valle

    2011-01-01

    Resumo:Dentre os muitos efeitos deleterios provocados pelo processo de eutrofizacao de aguas naturais, importante destaque deve ser dado ao surgimento de floracoes de cianobacterias e a consequente geracao de cianotoxinas de potente efeito hapatotoxico (ex. Microcistina-LR). Em geral, rotinas convencionais para potabilizacao da agua se mostram ineficientes para a remocao destes micropoluentes, o que tem estimulado o estudo de novas alternativas de tratamento. O presente trabalho teve como pri...

  2. Modeling and parametric study of a 1 kWe HT-PEMFC-based residential micro-CHP system

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2011-01-01

    A detailed thermodynamic, kinetic and geometric model of a micro-CHP (Combined-Heatand-Power) residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC) technology is developed, implemented and validated. HT-PEMFC technology is investigated as a possible candidate...

  3. Theoretical analysis of a biogas-fed PEMFC system with different hydrogen purifications: Conventional and membrane-based water gas shift processes

    International Nuclear Information System (INIS)

    Authayanun, Suthida; Aunsup, Pounyaporn; Patcharavorachot, Yaneeporn; Arpornwichanop, Amornchai

    2014-01-01

    Highlights: • Thermodynamic analysis of the biogas-fed PEMFC system is performed. • Conventional and membrane-based WGS processes for H 2 purification are studied. • A flowsheet model of the PEMFC system is developed. • Effect of key parameters on yields of H 2 and carbon in the biogas reformer is shown. • Performance of PEMFC systems with different H 2 purification processes is analyzed. - Abstract: This study presents a thermodynamic analysis of biogas reforming and proton electrolyte membrane fuel cell (PEMFC) integrated process with different hydrogen purifications: conventional and membrane-based water gas shift processes. The aim is to determine the optimal reforming process for hydrogen production from biogas in the PEMFC system. The formation of carbon is concerned in the hydrogen production. The simulation results show that increases in the steam-to-methane ratio and reformer temperature can improve the hydrogen yield and reduce the carbon formation. From the performance analysis, it is found that when the PEMFC is operated at high temperature and fuel utilization, the overall system efficiency enhances. The performance of the PEMFC system with the installation of a water gas shift membrane unit in the hydrogen purification step is slightly increased, compared with a conventional process

  4. Membranas híbridas basadas en estireno-metacrilato-sílice y ácido fosfowolfrámico obtenidas por sol-gel para pilas de combustible de intercambio protónico (PEMFC

    Directory of Open Access Journals (Sweden)

    Mosa, J.

    2007-10-01

    Full Text Available Contrary to internal combustion engines, proton-exchange membrane fuel cells (PEMFC used in transportation operate with zero emissions of environmental pollutants. The increase of the operation temperature in PEMFC above 100°C is a great concern for the application of this type of cells in electric vehicles. Hybrid organic-inorganic membranes with nanosized interfaces can combine the main properties of their components to meet this objective. Styrene-methacrylate-silica membranes doped with phosphotungstic acid (PWA were prepared through acid catalyzed sol-gel process and free-radical copolymerization. Additionally, sulfonation processes of aromatic rings to produce attached SO3H groups were applied to increase the proton conductivity. The effect of sulfonation degree and PWA doping on the membrane properties such as chemical and thermal stability, water uptake, ion exchange capacity, and proton conductivity were investigated. The measurement of conductivity shows a general increase with rising temperatures and with the increasing of SO3H groups density, reaching a maximum value of 3.2 10-3 S/cm at 130ºC and 100%HR.

    Comparadas con los motores de combustión interna, las pilas de combustible de intercambio de protones (PEMFC son capaces de operar sin emisiones de agentes contaminantes. El aumento de la temperatura de operación de la pila de combustible por encima de 100ºC es uno de los grandes objetivos en este campo ya que facilitaría el desarrollo comercial de los vehículos eléctricos impulsados por pilas de combustible. Las membranas híbridas orgánico-inorgánicas nanoestructuradas combinan las propiedades necesarias para este tipo de aplicación. Se obtuvieron membranas híbridas dopadas con ácido fosfowolfrámico (PWA por copolimerización radicálica a partir de alquilalcóxidos y monómeros de estireno y metacrilato, y por reacción sol-gel vía catálisis ácida. La conductividad protónica se logra realizando un proceso

  5. Synthesis and characterization of RUM catalysts (M=SE,MO,W,SN) applied in ORR for a PEMFC fuel battery; Sintesis y caracterizacion de catalizadores RUM (M=SE,MO,W,SN) aplicados en la RRO para una pila de combustible PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Ezeta-Mejia, A.; Arce Estrada, E.M. [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)]. E-mail: araceli-ezeta@hotmail.com; earce@ipn.mx

    2009-09-15

    Proton exchange membrane fuel cells (PEMFC) have received a great deal of interest recently because of a variety of factors, such as low weight and volume, operating at low temperatures and offering a high combination of power density and high efficiency in the conversion of energy, making them adequate for portable applications. Nevertheless, oxygen reduction reaction (ORR) occurring in the cathode of the battery plays a determinant role as the limiting reaction. Therefore, more efficient electrocatalysts need to be used. The optimal electrocatalyst for this reaction is Pt, but because of its high cost, alternative low-cost electrocatalysts with high activity and stability have been sought. Many investigations have shown that the Pt-based binary catalysts, such as Pt-M (M= Co, Fe, etc.) present good electrocatalytic activity for ORR; other studies show that Ru-based catalysts (RuSe, RuSe,Mo, RuSeRh ) also have adequate activity for this reaction. This study reports on synthesis by mechanical alloying of RuPt{sub x}M (x=0, 0.6% and M=Se,Mo,W,Sn) electrocatalyst nanoparticles at different grinding durations (0, 20 and 40 h). The materials synthesized by mechanical alloying were characterized using sweep electron microscopy and x-ray diffraction, obtaining agglomerated and dispersed particles between 1 and 30 {mu}m. The electrocatalytic characterization was conducted using VC and EDR techniques in H{sub 2}SO{sub 4} 0.5 M solution at ambient temperatures. The systems present a reaction order of 1 with respect to ORR and an overall multi-electron transfer of 4e{sup -} for the formation of water. A comparison was made between the electrocatalytic activity in the presence and absence of Pt, showing that Pt increases the catalytic activity of the materials by at least 1 order of magnitude. [Spanish] Las pilas de combustible de Membrana de Intercambio Protonico (PEMFC) han recibido gran interes recientemente por diversos factores tales como su bajo peso y volumen, operan a

  6. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

    Yli-Rantala, E.; Pasanen, A.; Kauranen, P.

    2011-01-01

    (PANI) precursor. The modified surfaces were studied by FTIR and XPS and the electrochemical characterization, including long-term Pt stability tests, was performed using a low-temperature PEMFC single cell. The performance and stability of the G-CNF supported catalysts were compared with a CB supported...

  7. Evidence of a non-dimensional parameter controlling the flooding of PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Buaud, Fabrice; Lelandais, Damien [Heat and Energy Department, Polytech' Nantes, Nantes University, Rue Christian Pauc, BP50609, 44 306 Nantes Cedex 3 (France); Auvity, Bruno [Heat and Energy Department, Polytech' Nantes, Nantes University, Rue Christian Pauc, BP50609, 44 306 Nantes Cedex 3 (France); Laboratoire de Thermocinetique de Nantes (CNRS-UMR 6607) (France)

    2008-06-15

    Water management is a key issue to get satisfactory and stable Polymer exchange membrane fuel cell (PEMFC) performances. The work reported in the present paper focuses on the determination of the operational conditions when using PEMFC stack working with ambient air without extra humidification. The objectives are to reduce as much as possible the auxiliaries consumptions. As far as the reaction air blower is concerned, the specific goal of the present tests is to find the minimum air flow rate to feed the PEMFC stack in order to prevent flooding. Our particular interest concerns the control of a PEMFC stack to power a prototype vehicle for the Shell Eco Marathon race. Tests are then conducted on a wide range of stoichiometry, for different values of current and stack temperature using ambient air. Flooding is shown to depend on all these parameters. A water balance calculation is developed comparing the amount of water produced by the electrochemical reaction to the amount of water transported as vapour in the exit air flow minus the amount of water incoming the stack in the ambient air. A non-dimensional number called the Flooding Number is constructed. This balance is first considered in the ideal case with the theoretical flow rate of reactants and products. It is shown that the stack temperature and the stoichiometry are the main order parameters and that conditions of ambient air have only secondary effects on the water balance. In a second step, the Flooding Number is evaluated for all the experimental tests. A critical Flooding Number appears clearly delimiting the range of operational conditions for which stack flooding appears. This result allows us to control the air blower and the cooling fan during the runs at the Shell Eco Marathon 2007 race in order to reduce hydrogen consumption due to auxiliaries. The non-dimensional number exhibited in the present paper is believed to be relevant to stack flooding. It can be used for any PEMFC stack to make clear

  8. Numerical Study on the Cooling Characteristics of a Passive-Type PEMFC Stack

    International Nuclear Information System (INIS)

    Lee, Jae Hyuk; Kim, Bo Sung; Lee, Yong Taek; Kim, Yong Chan

    2010-01-01

    In a passive-type PEMFC stack, axial fans operate to supply both oxidant and coolant to cathode side of the stack. It is possible to make a simple system because the passive-type PEMFC stack does not require additional cooling equipment. However, the performance of a cooling system in which water is used as a coolant is better than that of the air-cooling system. To ensure system reliability, it is essential to make cooling system effective by adopting an optimal stack design. In this study, a numerical investigation has been carried out to identify an optimum cooling strategy. Various channel configurations were applied to the test section. The passive-type PEMFC was tested by varying airflow rate distribution at the cathode side and external heat transfer coefficient of the stack. The best cooling performance was achieved when a channel with thick ribs was used, and the overheating at the center of the stack was reduced when a case in which airflow was concentrated at the middle of the stack was used

  9. Strategies for optimizing the opening of the outlet air circuit's nozzle to improve the efficiency of the PEMFC generator

    Energy Technology Data Exchange (ETDEWEB)

    Tirnovan, R. [Power Systems Department, Technical University of Cluj-Napoca (Romania); Giurgea, S.; Miraoui, A. [Fuel Cell Lab, University of Technology of Belfort-Montbeliard (France)

    2011-04-15

    The aim of this study is the optimal dimensioning of the air circuit's outlet nozzle in relation with the load duration curve, for a given PEMFC generator, in order to maximize the PEMFC efficiency and to increase the net outlet power. The steady state PEMFC operation has been taken into account. The model of the PEMFC system used in the work is based on a moving least squares technique. A centrifugal compressor has been taken into account, and the operating line of the compressor has been evaluated for an optimal fixed opening of the outlet nozzle. A multi-level optimization procedure has been implemented to solve the optimization problem. The developed algorithm is useful to design an optimum air subsystem, reducing the number of the control variables and the consequences of the dynamic behavior of a controlled electric adjustable valve on the PEMFC performance. The results of the work can contribute to the improvement of the PEMFC generator reliability and of its cost/performance ratio. (author)

  10. Performance study of a dual power source residential CCHP system based on PEMFC and PTSC

    International Nuclear Information System (INIS)

    Chen, Xi; Gong, Guangcai; Wan, Zhongmin; Zhang, Caizhi; Tu, Zhengkai

    2016-01-01

    Highlights: • A novel dual power source residential CCHP system model is proposed. • Low temperature and high current density guarantee the high efficiency of PTSC. • High system efficiency can be obtained at a relatively low solar radiation. • Government subsidy is a crucial factor to improve system economic performance. • System environmental performance is discussed by parametric study. - Abstract: This paper presents an innovative, hybrid residential CCHP system based on fuel cell and solar technologies that can provide electric power, heating and cooling. The CCHP system consists of a proton exchange membrane fuel cell (PEMFC) stack, parabolic trough solar collector (PTSC), double-effect absorption chiller and their relevant accessories. The effects of key operating parameters for PEMFC and PTSC systems (e.g.: current density, operating temperature and solar radiation) on the system thermodynamic performance are analyzed and discussed. The results show that the PEMFC operation temperature has a significant influence on the PTSC output performance in a hybrid CCHP system and that the PTSC also plays an important role as a bridge between the PEMFC stack and absorption chiller. The maximum efficiency of a hybrid system can reach 80.5%, which is higher than conventional CCHP systems, due to the high efficiency of PEMFC, PTSC and double-effect absorption chiller. The economic and environmental analysis of CCHP system are also performed, the results indicate the project is practicable, meanwhile, high current density and solar radiation and low operating temperature can improve pollutant emissions reduction of the system.

  11. Study on Air-cooled Self-humidifying PEMFC Control Method Based on Segmented Predict Negative Feedback Control

    International Nuclear Information System (INIS)

    Zhiyu, You; Tao, Xu; Zhixiang, Liu; Yun, Peng; Weirong, Cheng

    2014-01-01

    In order to obtain the optimal output performance of the air-cooled self-humidifying proton exchange membrane fuel cell (PEMFC), the operating temperature, the air flow, purge interval and some other parameters must be controlled strictly. As a key factor, the operating temperature mainly determines the optimal output performance of the fuel cell. However, some intrinsic issues such as long adjusting time, over-shoot still exist inevitably for the traditional PID temperature-controlled method in circumstances of the load variation. Consequently, output performance of PEMFC decreases because the operating temperature of the fuel cell fails to reach, and the corresponding lifetime of PEMFC is also reduced. In this study, a segmented predict negative feedback control method, based on the advance proportional control one, is proposed and verified by experiments to overcome the shortcomings of PID temperature control. The results demonstrate that the optimal output performance of PEMFC can be realized by utilizing the proposed method for temperature control due to its excellent properties, simple controlling and small over-shoot

  12. Search for ideal metal hydrides for PEMFC applications

    International Nuclear Information System (INIS)

    Perng, T.-P.; Shen, C.-C.

    2004-01-01

    'Full text:' Previously, an LmNi5-based alloy was prepared and its hydrogenation properties were studied. In order to make use of such a type of metal hydride for application in PEMFC, the room-temperature desorption pressure has to be adjusted to 1-2atm and the cyclic stability has to be maintained. In this study, the same alloy was partially substituted with Al and cyclic hydrogenation was conducted with different hydrogen loadings up to 3000 cycles at room temperature. The saturated hydrogen loadings in equilibrium were controlled at H/M = 0.75 and 1.0. The P-C-T curves after 1000, 2000, and 3000 cycles of test were collected at T=30, 50, and 70 o C. After 3000 cycles, it is observed that the maximum hydrogenation capacities of the samples for the loadings of 0.75 and 1.0 are reduced to 0.93 and 0.91, respectively. The plateaus do not change much for T=30 and 50 o C, but become little sloped without observable split at 70 o C. X-ray diffraction analysis shows that the strains associated with repeated hydrogenation are isotropic for all samples. Both unsubstituted and Al-substituted alloys were then used to store hydrogen in a small cylinder with a diameter 10mm and length of 40 mm. The cylinder was connected to a small PEMFC for discharge test at room temperature. More than 540ml H2 was released at below 2atm and discharged to a capacity of 1200mAh. The hydrogenation properties of the alloys and design of the hydrogen storage cylinder for application in small portable PEMFCs for electronic devices are evaluated. The effect of Al substitution and hydrogen loading on cyclic hydrogenation property of the LmNi5-based alloy is also discussed. (author)

  13. Characterizing the structural degradation in a PEMFC cathode catalyst layer : carbon corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Young, A.; Stumper, J. [Ballard Power Systems, Burnaby, BC (Canada); Gyenge, E. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering

    2009-07-01

    The structural degradation resulting from carbon corrosion of a cathode catalyst layer in a polymer electrolyte membrane fuel cell (PEMFC) was investigated in this study. In order to oxidize the catalyst carbon support, the PEMFC catalyst layer was subjected to a 30 hour accelerated stress test that cycled the cathode potential from 0.1 to 1.5 VRHE at 30 and 150 second intervals. The rate and amount of carbon loss was determined by measuring the carbon dioxide in the exhaust gas. The structural degradation of the catalyst layer was characterized and correlated to the PEMFC performance using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and polarization analyses. This analysis revealed a clear thinning of the cathode catalyst layer and gas diffusion layer carbon sub-layer, and a reduction in the effective platinum surface area due to the carbon support oxidation. The thinned cathode catalyst layer changed the water management, and increased the voltage loss associated with the oxygen mass transport and catalyst layer ohmic resistance. In order to further develop and verify this methodology for other degradation mechanisms, emphasis was placed on EIS measurements.

  14. Characteristics of PEMFC operating at high current density with low external humidification

    International Nuclear Information System (INIS)

    Fan, Linhao; Zhang, Guobin; Jiao, Kui

    2017-01-01

    Highlights: • PEMFC with low humidity and high current density is studied by numerical simulation. • At high current density, water production lowers external humidification requirement. • A steady anode circulation status without external humidification is demonstrated. • The corresponding detailed internal water transfer path in the PEMFC is illustrated. • Counter-flow is superior to co-flow at low anode external humidification. - Abstract: A three-dimensional multiphase numerical model for proton exchange membrane fuel cell (PEMFC) is developed to study the fuel cell performance and water transport properties with low external humidification. The results show that the sufficient external humidification is necessary to prevent the polymer electrolyte dehydration at low current density, while at high current density, the water produced in cathode CL is enough to humidify the polymer electrolyte instead of external humidification by flowing back and forth between the anode and cathode across the membrane. Furthermore, a steady anode circulation status without external humidification is demonstrated in this study, of which the detailed internal water transfer path is also illustrated. Additionally, it is also found that the water balance under the counter-flow arrangement is superior to co-flow at low anode external humidification.

  15. Validation of a HT-PEMFC stack for CHP applications

    Energy Technology Data Exchange (ETDEWEB)

    Pasupathi, S.; Ulleberg, Oe. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Bujlo, P. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Electrotechnical Institute Wroclaw Division (Poland); Scholta, J. [Centre for Solar Energy and Hydrogen Research (ZSW) (Germany)

    2010-07-01

    Fuel cell systems are very attractive for stationary co-generation applications as they can produce heat and electricity efficiently in a decentralized and environmentally friendly manner. PEMFC stacks operating at temperatures above 120 C, specifically in the range of 140-180 C, are ideal for co-generation purposes. In this study, preliminary results from a HTPEMFC stack designed for CHP applications is presented and discussed. A short, five-cell, HT-PEMFC stack was assembled with Celtec- P-2100 MEAs and validated in terms of electrical performance. The stack was operated with hydrogen and air at 160 C and the utilization curves for anode and cathode were recorded for a wide range of gas utilization at a current density of 0.52 A/cm{sup 2}. The current voltage characteristic was measured at optimal utilization values at 160 C. A 1kW stack is assembled and is currently being validated for its performance under various operating conditions for use in CHP applications. (orig.)

  16. CFD investigating the effects of different operating conditions on the performance and the characteristics of a high-temperature PEMFC

    International Nuclear Information System (INIS)

    Su, A.; Ferng, Y.M.; Shih, J.C.

    2010-01-01

    The effects of different operating conditions on the performance and the characteristics of a high-temperature proton exchange membrane fuel cell (PEMFC) are investigated using a three-dimensional (3-D) computational fluid dynamics (CFD) fuel-cell model. This model consists of the thermal-hydraulic equations and the electrochemical equations. Different operating conditions studied in this paper include the inlet gas temperature, system pressure, and inlet gas flow rate, respectively. Corresponding experiments are also carried out to assess the accuracy of this CFD model. Under the different operating conditions, the PEMFC performance curves predicted by the model correspond well with the experimentally measured ones. The performance of PEMFC is improved as the increase in the inlet temperature, system pressure or flow rate, which is precisely captured by the CFD fuel cell model. In addition, the concentration polarization caused by the insufficient supply of fuel gas can be also simulated as the high-temperature PEMFC is operated at the higher current density. Based on the calculation results, the localized thermal-hydraulic characteristics within a PEMFC can be reasonably captured. These characteristics include the fuel gas distribution, temperature variation, liquid water saturation distribution, and membrane conductivity, etc.

  17. Reviewing metallic PEMFC bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Turner, J.A. [National Renewable Energy Laboratory, Golden, CO (United States)

    2010-08-15

    A bipolar plate is one of the most important components in a polymer exchange membrane fuel cell (PEMFC) stack and has multiple functions. Metallic bipolar plate candidates have advantages over composite rivals in excellent electrical and thermal conductivity, good mechanical strength, high chemical stability, very wide alloy choices, low cost and, most importantly, existing pathways for high-volume, high-speed mass production. The challenges with metallic bipolar plates are the higher contact resistance and possible corrosion products, which may contaminate the membrane electrode assembly. This review evaluates the candidate metallic and coating materials for bipolar plates and gives the perspective of the research trends. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  18. Systematic studies of the gas humidification effects on spatial PEMFC performance distributions

    International Nuclear Information System (INIS)

    Reshetenko, Tatyana V.; Bender, Guido; Bethune, Keith; Rocheleau, Richard

    2012-01-01

    Highlights: ► We investigated impacts of gases humidification on a local PEMFC performance. ► The spatial performance and EIS were studied by a segmented cell system. ► The data were analyzed in the terms of voltage losses. ► A reduction in anode/cathode gases humidification decreased a PEMFC performance. ► A decrease of humidification led to non-uniform performances and voltage losses distributions. - Abstract: The overall current density that is measured in a proton exchange membrane fuel cell (PEMFC) represents the average of the local reaction rates. The overall and local PEMFC performances are determined by several primary loss mechanisms, namely activation, ohmic, and mass transfer. Spatial performance and loss variabilities are significant and depend on the cell design and operating conditions. A segmented cell system was used to quantify different loss distributions along the gas channel to understand the effects of gas humidification. A reduction in the reactant stream humidification decreased cell performance and resulted in non-uniform distributions of overpotentials and performance along the flow field. Activation and ohmic overpotentials increased with a relative humidity decrease due to insufficient membrane and catalyst layer hydration. The relative humidity of the cathode had a strong impact on the mass transfer overpotential due to a lower oxygen permeability through the dry Nafion film covering the catalyst surface. The mass transfer loss distribution was non-uniform, and the mass transfer overpotential increased for the outlet segments due to the oxygen consumption at the inlet segments, which reduced the oxygen concentration downstream, and a progressive water accumulation from upstream segments. Electrochemical impedance spectroscopy (EIS) and an equivalent electric circuit (EEC) facilitated the analysis and interpretation of the segmented cell data.

  19. Optimization of a PEMFC/battery pack power system for a bus application

    International Nuclear Information System (INIS)

    Barelli, Linda; Bidini, Gianni; Ottaviano, Andrea

    2012-01-01

    Highlights: ► A dynamic model of a PEMFC/battery system for bus traction has been developed. ► The model incorporates the dynamics of the fuel cell and the state of charge (SOC) of the battery pack. ► The system output power have been determined according to the real driving load demand of a bus during 12 h. ► The model has allowed the sizing of the fuel cell and the hydrogen tank with the SOC control strategy optimization. ► The PEMFC power that allows to optimize the operation in terms of both SOC control strategy and consumption is 33 kW e . -- Abstract: In a global environment context in which the urgent need to reduce pollutant emissions is of central relevance, it is becoming increasingly important the research for solutions, concerning the vehicular transport sector with low environmental impact. Fuel cell technology is expected to become a viable solution for these applications due to its environmental friendly characteristics. The present study concerns the traction system of a bus considering the case of hybrid solutions consisting of a proton exchange membrane fuel cell (PEMFC) in parallel with a battery pack. In particular, a dynamic model of a PEMFC/battery system is presented for the application under study. The model incorporates the dynamics of the fuel cell and the state of charge (SOC) of the battery pack. The fuel cell and the battery output power have been determined according to the real driving load demand of a bus taking into consideration a daily operation of 12 h. Such a model has allowed the correct dimensioning of the hybrid power system (giving a particular attention to the fuel cell and the hydrogen tank) together with the optimization of the SOC control strategy.

  20. Technology leadership: a road map to commercially viable PEMFC stack technology. Paper no. IGEC-1-008

    International Nuclear Information System (INIS)

    Stone, C.

    2005-01-01

    'Full text:' In February 2005, Ballard announced its most recent advances in PEMFC stack technology. This technology development exhibited, we believe, for the first time the capability of a single PEMFC stack design to demonstrate combined excellence in cost reduction, freeze start capability from -20 C and durability under an automotive OEM defined dynamic operating cycle, comparable to that experienced by a fuel cell stack in an actual vehicle. One month later, building on the above technology leadership demonstration, Ballard announced a technology ' oad map' that defined a path to commercially viability for a PEMFC stack by 2010. The key target parameters for cost reduction, durability, freeze start and stack power density are described in detail along with demonstrated historical capability and a clear path as to how Ballard will achieve the required targets. (author)

  1. Desenvolvimento de tecnologia para confecção de eletrodos e conjuntos eletrodo-membrana-eletrodo (MEA por impressão à tela para aplicação em módulos de potência de células PEMFC

    Directory of Open Access Journals (Sweden)

    Valéria Cristina Fernandes

    2012-01-01

    Full Text Available Significant functions in the Proton Exchange Membrane Fuel Cells (PEMFCs rely on Gas Diffusion Layers (GDLs, such as control the water balance in the membrane electrode assembly (MEA, allow suitable gas permeability and porosity, etc. Aware of the GDL importance in the cell performance and its great demand in scale-up projects, the fuel cell research group at Instituto de Pesquisas Energéticas e Nucleares (IPEN has developed a Sieve Printing method (innovative in Brazil as a strategic solution for producing GDL and electrodes used in high power PEMFC stacks. The method has shown to be adequate to fabricate low cost electrodes, GDLs of different dimensions and to produce any amount of MEAs for power stacks.

  2. Technology leadership : a road map to commercially viable PEMFC stack technology

    Energy Technology Data Exchange (ETDEWEB)

    Stone, C. [Ballard Power Systems, Burnaby, BC (Canada)

    2005-07-01

    This abstract discussed recent advances in stack technology by Ballard Power Systems. The technology department of this Canadian-owned company exhibited the capability of a single proton exchange membrane fuel cell (PEMFC) stack design to demonstrate that cost reduction, freeze start capability from -20 degrees C and durability under an automotive dynamic operating cycle are comparable to that experienced by a fuel cell stack in an actual vehicle. A technology road map has been developed by the company to define a path to the commercial viability of the PEMFC stack by 2010. Key target parameters for cost reduction, durability, freeze start and stack power density were described in detail along with demonstrated historical capability and details of how the company will achieve its required targets. refs., tabs., figs.

  3. Technology leadership: a road map to commercially viable PEMFC stack technology. Paper no. IGEC-1-008

    Energy Technology Data Exchange (ETDEWEB)

    Stone, C. [Ballard Power Systems, Burnaby, British Columbia (Canada)

    2005-07-01

    'Full text:' In February 2005, Ballard announced its most recent advances in PEMFC stack technology. This technology development exhibited, we believe, for the first time the capability of a single PEMFC stack design to demonstrate combined excellence in cost reduction, freeze start capability from -20 C and durability under an automotive OEM defined dynamic operating cycle, comparable to that experienced by a fuel cell stack in an actual vehicle. One month later, building on the above technology leadership demonstration, Ballard announced a technology {sup '}oad map' that defined a path to commercially viability for a PEMFC stack by 2010. The key target parameters for cost reduction, durability, freeze start and stack power density are described in detail along with demonstrated historical capability and a clear path as to how Ballard will achieve the required targets. (author)

  4. Cell layer level generalized dynamic modeling of a PEMFC stack using VHDL-AMS language

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fei; Blunier, Benjamin; Miraoui, Abdellatif; El-Moudni, Abdellah [Transport and Systems Laboratory (SeT) - EA 3317/UTBM, University of Technology of Belfort-Montbeliard, Rue Thierry Mieg, 90000 Belfort (France)

    2009-07-15

    A generalized, cell layer scale proton exchange membrane fuel cell (PEMFC) stack dynamic model is presented using VHDL-AMS (IEEE standard Very High Speed Integrated Circuit Hardware Description Language-Analog and Mixed-Signal Extensions) modeling language. A PEMFC stack system is a complex energy conversion system that covers three main energy domains: electrical, fluidic and thermal. The first part of this work shows the performance and the advantages of VHDL-AMS language when modeling such a complex system. Then, using the VHDL-AMS modeling standards, an electrical domain model, a fluidic domain model and a thermal domain model of the PEMFC stack are coupled and presented together. Thus, a complete coupled multi-domain fuel cell stack 1-D dynamic model is given. The simulation results are then compared with a Ballard 1.2 kW NEXA fuel cell system, and show a great agreement between the simulation and experimentation. This complex multi-domain VHDL-AMS stack model can be used for a model based control design or a Hardware-In-the-Loop application. (author)

  5. Performance evaluation of integrated fuel processor for residential PEMFCs application

    International Nuclear Information System (INIS)

    Yu Taek Seo; Dong Joo Seo; Young-Seog Seo; Hyun-Seog Roh; Wang Lai Yoon; Jin Hyeok Jeong

    2006-01-01

    KIER has been developing the natural gas fuel processor to produce hydrogen rich gas for residential PEMFCs system. To realize a compact and high efficiency, the unit processes of steam reforming, water gas shift, and preferential oxidation are chemically and physically integrated in a package. Current fuel processor designed for 1 kW class PEMFCs shows thermal efficiency of 78% as a HHV basis with methane conversion of 90% at rated load operation. CO concentration below 10 ppm in the produced gas is achieved with preferential oxidation unit using Pt and Ru based catalyst under the condition of [O 2 ]/[CO]=2.0. The partial load operation have been carried out to test the performance of fuel processor from 40% to 80% load, showing stable methane conversion and CO concentration below 10 ppm. The durability test for the daily start-stop and 8 hr operation procedure is under investigation and shows no deterioration of its performance after 40 start-stop cycles. (authors)

  6. Kladná elektroda na bázi MnOx pro PEMFC

    OpenAIRE

    Šmídek, Miroslav

    2011-01-01

    Předkládaná bakalářská práce uvádí do problematiky vodíkových palivových článků a zaměřuje se na nízkoteplotní palivové články s polymerním elektrolytem (PEMFC). Základním zaměřením práce je studium vlastností katalyzátorů na bázi MnOx na reálném palivovém článku typu PEMFC. Výstupem jsou pak změřené charakteristiky takto vytvořeného palivového článku. Construed bachelor work features into problems hydrogen fuel articles and survey on low-temperature fuell elements with polymeric electroly...

  7. Catalyst FeNi supported on nanometric mezoporous oxide for PEMFC applications

    DEFF Research Database (Denmark)

    Serban, E. C.; Banu, N.; Marinescu, A. C.

    2011-01-01

    Proton exchange membrane fuel cells (PEMFC) are studied intensive for hydrogen - oxygen couple conversion into electrical power via electro-chemical process. Electrocatalyst performances (defined by specific area and catalytic activity) represent a key point for hydrogen oxidation - anode reaction...

  8. Modeling and simulation of a residential micro-CHP system based on HT-PEMFC technology

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2009-01-01

    Combined-heat-and-power (CHP) technology is a well known and proved method to produce simultaneously power and heat at high efficiencies. This can be further improved by the introduction of a novel micro-CHP residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC......). The HT-PEMFC (based on PBI-membrane technology) operates at temperatures near 200oC, and this can be an ideal match for cogeneration residential systems. The proposed system provides electric power, hot water, and space heating for a typical household (1-5 kWe, 5-10 kWth). The micro-CHP system...

  9. Nafion/Zeolite nanocomposite membrane for high temperature PEMFCS

    International Nuclear Information System (INIS)

    Chen, Z.

    2009-01-01

    'Full text': The Nafion/Acid Functionalized Zeolite Beta (NAFB) nanocomposite membrane has been successfully prepared by the in situ hydrothermal crystallization method. Acid Functionalized Zeolite Beta (AFB) nanocrystals less than 20 nm were formed and embedded into the Nafion matrix. The physical-chemical properties of all membranes were investigated regarding their tensile strength, water uptake and thermogravimetric analyzer (TGA). The proton conductivity commercial Nafion membrane and the NAFB composite membrane were measured with different relative humidity (RH) at 80 and 120 o C. Compared with the commercial Nafion membrane, the NAFB composite membrane has much higher proton conductivity at 120 o C and reduced RH. The NAFB composite membrane and commercial Nafion membranes were also studied in an H 2 /O 2 PEMFC over a wide range of RH values from 25 to 100% at temperatures of 80 and 120 o C. The NAFB composite membrane showed a pronounced improvement over commercial Nafion membranes when operated at 120 o C and reduced RH. The high performance of the NAFB composite membranes at low RH was attributed to improved water retention due to the presence of absorbed water species within the pores and on the surface of AFB. NAFB composite membranes have the potential for use with high temperature PEMFC. (author)

  10. Hollow microspheres with a tungsten carbide kernel for PEMFC application.

    Science.gov (United States)

    d'Arbigny, Julien Bernard; Taillades, Gilles; Marrony, Mathieu; Jones, Deborah J; Rozière, Jacques

    2011-07-28

    Tungsten carbide microspheres comprising an outer shell and a compact kernel prepared by a simple hydrothermal method exhibit very high surface area promoting a high dispersion of platinum nanoparticles, and an exceptionally high electrochemically active surface area (EAS) stability compared to the usual Pt/C electrocatalysts used for PEMFC application.

  11. Performance improvement of the circular tubular PEMFC by using different architectures and number of layers

    International Nuclear Information System (INIS)

    Mohammadi-Ahmar, Akbar; Osanloo, Behzad; Solati, Ali; Ghasemi, Jalal

    2016-01-01

    Highlights: • A full three-dimensional model was developed for cylindrical PEMFC. • CFD study on reactants distribution, current density and final power was performed. • Five cylindrical configurations were investigated (CP, C2C, C4C, C6C and C8C). - Abstract: The effects of arrangement and number of Membrane, Catalyst layer (CL) and Gas Diffusion layer (GDL) is investigated in present study. A full three-dimensional model was developed for tubular shaped PEMFC and the distribution of reactant concentration along anode and cathode channels, current density, power consumption and production were studied through computational Fluid dynamics (CFD). In order to do so, five arrangements of the tubular-shaped PEMFC namely: circular peripheral (CP), circular with two channels (C2C), circular with four channels (C4C), circular with six channels (C6C) and circular with eight channels (C8C) are presented. Comparison was made for new arrangements of layers, for the same active area and input mass flow in the anode and cathode. The results of polarization curve and power density shows that via increasing the number of layers, and thereby reducing the length of the fuel cell, more reactants are consumed along the tubular-shaped PEMFC. Among the five new arrangements, the CP case due to having high flow velocity for the same flow rate, has lower consumption along the channel and demonstrates undesirable results. Also in the dual-channel case (C2C) the core of the reacting flow is far from the reaction location (i.e. CL) therefor showed the lowest consumption and thus lowest power density. Whereas the eight-channel (C8C) configuration because of the appropriate distance between Membrane, CL and GDL layers and the core of the flow, increases the power output and reduces the cost, simultaneously due to shortest length in comparison to other cases. The results of present study can be employed for the manufacturing of new tubular-shaped PEMFC.

  12. Investigation of the prospect of energy self-sufficiency and technical performance of an integrated PEMFC (proton exchange membrane fuel cell), dairy farm and biogas plant system

    International Nuclear Information System (INIS)

    Guan, Tingting; Alvfors, Per; Lindbergh, Göran

    2014-01-01

    Highlights: • A PEMFC stack with a 40% of electrical efficiency will make the integrated PEMFC-CHP, biogas plant and dairy farm self-sufficient. • The quality of the reformate gas is good enough to support normal operation of the PEMFC-CHP. • The methane conversion rate and the content of the CH 4 in the biogas need to be balanced in order to obtain the best system performance. • Compared with a coal-fired CHP plant, the integrated system can avoid coal consumption and CO 2 emissions. - Abstract: A PEMFC fuelled with hydrogen is known for its high efficiency and low local emissions. However, the generation of hydrogen is always a controversial issue for the application of the PEMFC due to the use of fossil fuel and the possible carbon dioxide emissions. Presently, the PEMFC-CHP fed with renewable fuels, such as biogas, appears to be the most attractive energy converter–fuel combination. In this paper, an integrated PEMFC-CHP, a dairy farm and a biogas plant are studied. A PEMFC-CHP fed with reformate gas from the biogas plant generates electricity and heat to a dairy farm and a biogas plant, while the dairy farm delivers wet manure to the biogas plant as the feedstock for biogas production. This integrated system has been modelled for steady-state conditions by using Aspen Plus®. The results indicate that the wet manure production of a dairy farm with 300 milked cows can support a biogas plant to give 1280 MW h of biogas annually. Based on the biogas production, a PEMFC-CHP with a stack having an electrical efficiency of 40% generates 360 MW h electricity and 680 MW h heat per year, which is enough to cover the energy demand of the whole system while the total efficiency of the PEMFC-CHP system is 82%. The integrated PEMFC-CHP, dairy farm and biogas plant could make the dairy farm and the biogas plant self-sufficient in a sustainable way provided the PEMFC-CHP has the electrical efficiency stated above. The effect of the methane conversion rate and the

  13. The PEMFC-integrated CO oxidation — a novel method of simplifying the fuel cell plant

    Science.gov (United States)

    Rohland, Bernd; Plzak, Vojtech

    Natural gas and methanol are the most economical fuels for residential fuel cell power generators as well as for mobile PEM-fuel cells. However, they have to be reformed with steam into hydrogen, which is to be cleaned from CO by shift-reaction and by partial oxidation to a level of no more than 30 ppm CO. This level is set by the Pt/Ru-C-anode of the PEMFC. A higher partial oxidation reaction rate for CO than those of Pt/Ru-C can be achieved in an oxidic Au-catalyst system. In the Fe 2O 3-Au system, a reaction rate of 2·10 -3 mol CO/s g Au at 1000 ppm CO and 5% "air bleed" at 80°C is achieved. This high rate allows to construct a catalyst-sheet for each cell within a PEMFC-stack. Practical and theoretical current/voltage characteristics of PEMFCs with catalyst-sheet are presented at 1000 ppm CO in hydrogen with 5% "air bleed". This gives the possibility of simplifying the gas processor of the plant.

  14. Coordinating IMC-PID and adaptive SMC controllers for a PEMFC.

    Science.gov (United States)

    Wang, Guo-Liang; Wang, Yong; Shi, Jun-Hai; Shao, Hui-He

    2010-01-01

    For a Proton Exchange Membrane Fuel Cell (PEMFC) power plant with a methanol reformer, the process parameters and power output are considered simultaneously to avoid violation of the constraints and to keep the fuel cell power plant safe and effective. In this paper, a novel coordinating scheme is proposed by combining an Internal Model Control (IMC) based PID Control and adaptive Sliding Mode Control (SMC). The IMC-PID controller is designed for the reformer of the fuel flow rate according to the expected first-order dynamic properties. The adaptive SMC controller of the fuel cell current has been designed using the constant plus proportional rate reaching law. The parameters of the SMC controller are adaptively tuned according to the response of the fuel flow rate control system. When the power output controller feeds back the current references to these two controllers, the coordinating controllers system works in a system-wide way. The simulation results of the PEMFC power plant demonstrate the effectiveness of the proposed method. 2009 ISA. Published by Elsevier Ltd. All rights reserved.

  15. The impact of channel path length on PEMFC flow-field design

    Energy Technology Data Exchange (ETDEWEB)

    Shimpalee, S.; Greenway, S.; Van Zee, J.W. [Chemical Engineering Department, University of South Carolina, Columbia, SC 29208 (United States)

    2006-09-29

    Distributions in reactant species concentration in a PEMFC due to local consumption of fuel and local transport of water through the membrane cause distributions in current density, temperature, and water concentration in three dimensions in a PEMFC. These distributions can lead to flooding or drying of the membrane that may shorten the life of an MEA. Changing the cell's flow-field pattern to distribute the gas more evenly is one method of minimizing these stresses. This paper investigates how 200cm{sup 2} serpentine flow-fields with different number of gas paths, and thus different gas path lengths, affect performance and species distribution. The results show how the local temperature, water content, and current density distributions become more uniform for serpentine flow-field designs with shorter path lengths or larger number of channels. These results may be used to develop universal heuristics and dimensionless number correlations in the design of flow-fields and stacks. (author)

  16. Development of a membrane electrode as assembly production process for proton exchange membrane fuel cell (PEMFC) by sieve printing; Desenvolvimento de processo de producao de conjuntos eletrodo-membrana-eletrodo para celulas a combustivel baseadas no uso de membrana polimerica conditora de protons (PEMFC) por impressa a tela

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio, Rafael Nogueira

    2010-07-01

    Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants' emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of k W of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm{sup -2}) suitable for cathodes and 0.4 mgPt.cm{sup -2} for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 m A.cm{sup -2} by 600 mV to 25 cm{sup 2} MEA area. The MEA cost production for MEAs of 247.86 cm{sup 2}, that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor. (author)

  17. Progress in fuel processing for PEMFC systems for transport applications

    Energy Technology Data Exchange (ETDEWEB)

    Dams, A J; Hayter, P R; Moore, S C

    1998-07-01

    Wellman CJB Limited has been developing fuel processors for PEMFC systems for transport applications using a range of feedstocks. Feedstocks that can be processed to produce a hydrogen-rich gas stream suitable for use with a PEMFC include methanol, gasoline, diesel, LPG, dimethylether, marine diesel and aviation fuel. The basic fuel processor is a steam reformer combined with a selective carbon monoxide oxidation stage. Depending on the nature of the liquid feedstock, other process steps will be required such as vaporizer, desulfurizer, pre-reformer and high and low temperature shift reactors. Work on methanol reforming has been specifically targeted at a PEMFC driven passenger car as part of a multinational European Community JOULE programme called MERCATOX. The objective is to develop and test a compact and fast response methanol reformer and gas clean-up unit to meet a car manufacturer's specification. The method of construction is to coat a methanol reforming catalyst onto one side of a metal corrugated plate. On the other side is a coated combustion catalyst which burns fuel cell off-gas to provide the endothermic heat for the methanol reforming reaction. A number of these plates are assembled in a compact unit ensuring good heat transfer. The gas clean-up unit is similarly constructed with a selective oxidation catalyst on one side and a thermal fluid on the other. Initial tests have indicated a superior performance to conventional packed bed reformers in terms of response and start-up time. Steam reforming of gasoline, diesel, LPG, dimethylether, marine diesel and aviation fuel has been demonstrated on a bench scale (0.5kW). The process steps commence with vaporization (except for LPG), desulfurization (except for dimethylether), prereforming, reforming, low and high temperature shift and selective oxidation. A simple technology demonstrator has shown that a hydrogen-rich mixture (75% hydrogen, 25% carbon dioxide) with less than 2ppm carbon monoxide can be

  18. Preparation of gas diffusion layers for PEMFC fuel cells using carbon fibers; Elaboracao de uma camada de difusao de gas a partir de fibras de carbono para aplicacao em celulas combustiveis do tipo PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.N.; Kunsti, S.R.; Malfatti, C.F. [Universidade Federal do Rio Grande do Sul - Departamento de Metalurgia (PPGEM) - Laboratorio de Pesquisa em Corrosao (LAPEC), Porto Alegre, RS (Brazil); Vargas, J.V.C. [Universidade Federal do Parana - Departamento de Engenharia Mecanica, PR (Brazil); Amico, S.C. [Universidade Federal do Rio Grande do Sul - Departamento de Materiais, RS (Brazil)

    2010-07-01

    The electrode/membrane system, called MEA, is the fundamental unit of a PEMFC (proton exchange membrane fuel cell). Within the MEA, the gas diffusion layer (GDL) is the bridge between the flow field and the catalyst layer. One of the important elements in a GDL is the substrate, typically a carbon cloth or paper, that has to be an excellent electrical conductor and show mechanical strength along with thermal and chemical stability. In this work, GDLs were produced from a suspension containing short carbon fibers in water-based polyurethane and poly(vinyl alcohol) (PVA) resins with appropriate characteristics to be used in low temperature fuel cells. The obtained GDL was characterized regarding its wettability, electrical conductivity and morphological aspects, evaluated by SEM. (author)

  19. Technology watch of polymer fuel cells (PEMFC) 2012; Teknikbevakning av polymera braensleceller (PEMFC) 2012

    Energy Technology Data Exchange (ETDEWEB)

    Wreland Lindstroem, Rakel; Lindbergh, Goeran

    2013-03-15

    The commercial development of the PEMFC has made strong progress in recent years. Between 2010 and 2011, the number of units shipped increased by 87%. The forecast for 2012 is a further tripling of the number of units delivered to about 71000 during the year. Sales of stationary units are increasing, and they account for a third of the number of units and almost half of the rated power with a total of over 20 MW. The increase consists of a few large units and a continued growth in small combined heat and power plant for residential use (micro-CHP). The increase is also reflected by the Japanese catalyst manufacturer Tanaka which increased its sales of catalysts for fuel cells by 67% in 2011. The number of units for transport is still small but is believed to take over the market when fuel cell vehicles enter the market around the 2015. Combined heat and power plant for residential, micro-CHP, has gained ground in Japan. The systems under the name ENE-FARM is based on natural gas reformed and used in a PEMFC. The demand increased even further after the tsunami and nuclear disaster in 2011. The global market for micro-CHP, which is dominated by the Japanese market, grew by 38%. Since 2010, the Japanese system has improved and obtained higher electrical efficiency and become 20% cheaper. The interest in micro-CHP increase also in other countries. A Germany program had in June 2012 260 systems installed, and projected 550 systems at the end of 2013. A European program called ene.field brings together European producers and users in 12 member states to test various fuel cell technologies in around 1000 installations in buildings. In Korea, 350 micro-CHP systems have been produced in 2012. The large amount of hydrogen produced as a by-product in the chemical industry has recently been highlighted. The hydrogen is today typically burned to provide heat, but calculations show that if the gas instead is used in fuel cells the industry's electricity costs could be

  20. Development of master-slave energy management strategy based on fuzzy logic hysteresis state machine and differential power processing compensation for a PEMFC-LIB-SC hybrid tramway

    International Nuclear Information System (INIS)

    Peng, Fei; Zhao, Yuanzhe; Li, Xiaopeng; Liu, Zhixiang; Chen, Weirong; Liu, Yang; Zhou, Donghua

    2017-01-01

    Highlights: •A power system model for the PEMFC based commercial hybrid tramway was established. •An energy management strategy based on master FuHSM and slave DPPC was proposed. •The optimal OER operation of PEMFC subsystem was achieved. •The real-time EMS based HCM optimization was achieved. •The influence on system fuel economy and PEMFC performance degradation was verified. -- Abstract: A hybrid power system configuration based on proton exchange membrane fuel cell (PEMFC), lion-lithium battery (LIB) and supercapacitor (SC) was designed without grid connection for the hybrid tramway. To adapt to the rapid load power change and achieve higher fuel efficiency and optimal oxygen excess ratio (OER) operation of the PEMFC power subsystem, a master-slave energy management strategy based on fuzzy logic hysteresis state machine (FuHSM) and differential power processing compensation (DPPC) was proposed for the hybrid tramway, effectively taking into consideration of the dynamic response and optimum OER tracing of the integrated PEMFC subsystem. The master FuHSM controller was utilized to grantee the optimal power coordination of the multiple power sources and the slave DPPC controller was responsible for further compensating the load power demand to enhance the dynamic performance and bus voltage stability. Furthermore, the equivalent H 2 consumption minimization optimization considering characteristics of the proposed energy management strategy was realized by means of EIA-PSO algorithm to further improve the fuel economy of the overall hybrid power system. The results demonstrate that the proposed energy management strategy can guarantee the stability of the hybrid power system throughout the driving cycle. In addition, more efficient power coordination dynamics among the PEMFC, LIB and SC subsystems could be achieved without additional performance degradation of the integrated PEMFC subsystem, and the results of the comparisons with other control strategies

  1. Experimental approaches for distribution and behavior of water in PEMFC under flow direction and differential pressure using neutron imaging technique

    International Nuclear Information System (INIS)

    Kim, TaeJoo; Kim, JongRok; Sim, CheulMuu; Lee, SeungWook; Kaviany, Massound; Son, SangYoung; Kim, MooHwan

    2009-01-01

    In this investigation, we prepared a 3-parallel serpentine single PEMFC which has an active area of 25 cm 2 and a flow channel cross section of 1x1 mm. Distribution and transport of water in an operating PEMFC were observed by varying the flow directions (co-current and counter-current) in each channel and the differential pressures (100, 200, 300 kPa) applied between the anode and cathode channels. This investigation was performed at the neutron imaging facility at the NIST of which the collimation ratio and neutron fluence rate are 600, 7.2x10 6 n/s/cm 2 , respectively. Neutron image was continuously recorded by an amorphous silicon flat panel detector every 1 s during the operation of the fuel cell. It has been observed that the differential pressure affects the total amount of water produced while the flow direction affects the spatial distribution of water when the neutron images were analyzed for several different operating conditions. More specifically, the amount of water production in the fuel cell increased as the partial pressure increases at a given current density and the water production was more uniform for the counter current than the co-current case. It is shown that the neutron imaging technique is a powerful tool to visualize the PEMFC. The information on the water distribution and behavior at an operating PEMFC helps improve the efficiency of PEMFC.

  2. Polymers application in proton exchange membranes for fuel cells (PEMFCs)

    Science.gov (United States)

    Walkowiak-Kulikowska, Justyna; Wolska, Joanna; Koroniak, Henryk

    2017-07-01

    This review presents the most important research on alternative polymer membranes with ionic groups attached, provides examples of materials with a well-defined chemical structure that are described in the literature. Furthermore, it elaborates on the synthetic methods used for preparing PEMs, the current status of fuel cell technology and its application. It also briefly discusses the development of the PEMFC market.

  3. Experimental and computational analysis of a 1.2 kW PEMFC designed for communications backup power applications

    International Nuclear Information System (INIS)

    Krishnan, K.J.; Claveria, J.; Varadharajan, L.; Kalam, A.

    2011-01-01

    Usage of Fuel Cells due to their high power density and low greenhouse gas emissions which combine H/sub 2/ and O/sub 2/ electrochemically to produce electricity and H/sub 2/O as the by-product will become widespread in the near future due to its quality, reliability and portability. Among all types of fuel cells, Proton Exchange Membrane Fuel Cells (PEMFC) is most attractive for residential and automotive industry use due to its low operating temperature, silent operation, quick start-up characteristics and better performance. The T-1000 1.2 kW PEMFC are mainly used for communications backup power applications because of its high reliability, simplicity and ease of maintenance in telecommunication sector, utility and government etc. This paper discuses the features of T- 1000 PEMFC and also the production losses due to power outages in US and different parts of the globe and the advantages of using it in different sectors to reduce the production loses occurred by the power outages. This work focuses on the experimental data and the computational data of load, P, V, A and H/sub 2/ consumed under laboratory conditions at Power Lab in Victoria University, Melbourne. The paper also describes various load, P, V and A curves recorded at regular intervals between the experimental and computational data. The work shows notably the benefit of using T-1000 1.2 kW PEMFC for residential, automobile, government and telecom sectors. (author)

  4. Water Transport and Removal in PEMFC Gas Flow Channel with Various Water Droplet Locations and Channel Surface Wettability

    Directory of Open Access Journals (Sweden)

    Yanzhou Qin

    2018-04-01

    Full Text Available Water transport and removal in the proton exchange membrane fuel cell (PEMFC is critically important to fuel cell performance, stability, and durability. Water emerging locations on the membrane-electrode assembly (MEA surface and the channel surface wettability significantly influence the water transport and removal in PEMFC. In most simulations of water transport and removal in the PEMFC flow channel, liquid water is usually introduced at the center of the MEA surface, which is fortuitous, since water droplet can emerge randomly on the MEA surface in PEMFC. In addition, the commonly used no-slip wall boundary condition greatly confines the water sliding features on hydrophobic MEA/channel surfaces, degrading the simulation accuracy. In this study, water droplet is introduced with various locations along the channel width direction on the MEA surface, and water transport and removal is investigated numerically using an improved model incorporating the sliding flow property by using the shear wall boundary condition. It is found that the water droplet can be driven to the channel sidewall by aerodynamics when the initial water location deviates from the MEA center to a certain amount, forming the water corner flow in the flow channel. The channel surface wettability on the water transport is also studied and is shown to have a significant impact on the water corner flow in the flow channel.

  5. The effects of air stoichiometry and air excess ratio on the transient response of a PEMFC under load change conditions

    International Nuclear Information System (INIS)

    Kim, Bosung; Cha, Dowon; Kim, Yongchan

    2015-01-01

    Highlights: • Effects of controlling parameters on the transient response of a PEMFC are studied. • The transient response is measured by varying air stoichiometry and air excess ratio. • Voltage drop, undershoot, and voltage fluctuation are analyzed under the load change. • Optimal air stoichiometry and air excess ratio are suggested for stable operation. - Abstract: The transient response of a proton exchange membrane fuel cell (PEMFC) is an important issue for transportation applications. The objective of this study is to investigate the effects of operating and controlling parameters on the transient response of a PEMFC for achieving more stable cell performance under load change conditions. The transient response of a PEMFC was measured and analyzed by varying air stoichiometry, air humidity, and air excess ratio (AER). The optimal air stoichiometry and AER were determined to minimize the voltage drop, undershoot, and voltage fluctuation under the load change, while maintaining high cell performance. Based on the present data, the optimal air stoichiometry was determined to be between 2.0 and 2.5, and the optimal AER was suggested to be between 1.65 and 2.0

  6. PEMFC Performance with Metal Bipolar Plates Depending on the Channel Dimension

    Directory of Open Access Journals (Sweden)

    Kwon Kuikam

    2016-01-01

    Full Text Available Bipolar plates of a proton exchange membrane fuel cell (PEMFC play an important role in removing liquid phase water as a by-product in order to facilitate the reaction between fuel and oxygen. A great amount of effort has been made to improve the performance of a fuel cell such as maximum current density or maximum power, by improving water removability of a bipolar plate. Most of the studies, however, are conducted numerically because of the complexity of analysing gas and liquid and the poor manufacturability of graphite bipolar plates. In this proceeding, we demonstrate that the performance of a PEMFC with metal bipolar plates can be enhanced by reducing the dimension of the channel. Bipolar plates were machined with stainless steel (type 316L to have three different channel size (1000 μm, 500 μm and 300 μm and the performance of each assembled cells were tested. As a result, the maximum power density and the maximum current density increased by 25%.

  7. High Pt utilization PEMFC electrode obtained by alternative ion-exchange/electrodeposition.

    Science.gov (United States)

    Chen, Siguo; Wei, Zidong; Li, Hua; Li, Li

    2010-12-14

    High Pt utilization PEMFC electrodes were prepared by an alternative ion-exchange/electrodeposition (AIEE) technique. The results demonstrated that the MEA employing an AIEE electrode with a Pt loading of 0.014 mg Pt cm(-2) exhibits performance approximately 2.2 times larger than that employing a conventional Nafion-bonded Pt/C electrode with a same Pt loading.

  8. Effect of the prominent catalyst layer surface on reactant gas transport and cell performance at the cathodic side of a PEMFC

    International Nuclear Information System (INIS)

    Perng, Shiang-Wuu; Wu, Horng-Wen

    2010-01-01

    The cell performance enhancement of a proton exchange membrane fuel cell (PEMFC) has been numerically investigated with the prominence-like form catalyst layer surface of the same composition at the cathodic half-cell of a PEMFC. The geometries of the prominence-like form catalyst layer surface are assigned as one prominence, three prominences, and five prominences catalyst layer surfaces with constant distance between two prominences in the same gas diffusion layer (GDL) for the purpose of investigating the cell performance. To confine the current investigation to two-dimensional incompressible flows, we assume that the fluid flow is laminar with a low Reynolds number 15. The results indicate that the prominence-like form catalyst layer surface can effectively enhance the local cell performance of a PEMFC.

  9. Study of operational parameters on the performance of micro PEMFCs with different flow fields

    International Nuclear Information System (INIS)

    Hsieh, S.-S.; Yang, S.-H.; Kuo, J.-K.; Huang, C.-F.; Tsai, H.-H.

    2006-01-01

    The effects of different operating parameters on micro PEMFC performances were experimentally studied for three different flow field configurations (interdigitated, mesh, and serpentine). Experiments with different cell operating temperatures and different backpressures on the H 2 flow channels, as well as various combinations of these parameters, have been conducted for three different flow geometries. The micro PEMFCs were designed and fabricated inhouse through a deep UV lithography technique and the SU-8 photoresist was used as microstructure material for the fuel cell flow field plates. Results are presented in the form of polarization VI curves and PI curves under different operating conditions. The possible transport mechanisms associated with the parametric effects were discussed. In addition, it was found that among the three flow patterns considered, significant improvements can be reached with a specified flow geometry

  10. Synthesis and characterisation of binary electrocatalysts for electrochemical oxidation of ethanol in PEMFC

    CSIR Research Space (South Africa)

    Masombuka, T

    2008-06-01

    Full Text Available Ethanol is an alternative choice fuel for polymer electrolyte membrane fuel cells (PEMFC), due to its nontoxicity and its availability from biomass resources advocates its use in direct ethanol fuel cells. In this study PtSn/C and Pt...

  11. Control of the Air Supply Subsystem in a PEMFC with Balance of Plant Simulation

    Directory of Open Access Journals (Sweden)

    Alan Cruz Rojas

    2017-01-01

    Full Text Available This paper deals with the design of a control scheme for improving the air supply subsystem of a Proton Exchange Membrane Fuel Cell (PEMFC with maximum power of 65 kW. The control scheme is evaluated in a plant simulator which incorporates the balance of plant (BOP components and is built in the aspenONE® platform. The aspenONE® libraries and tools allows introducing the compressor map and sizing the heat exchangers used to conduct the reactants temperature to the operating value. The PEMFC model and an adaptive controller were programmed to create customized libraries used in the simulator. The structure of the plant control is as follows: the stoichiometric oxygen excess ratio is regulated by manipulating the compressor power, the equilibrium of the anode-cathode pressures is achieved by tracking the anode pressure with hydrogen flow manipulation; the oxygen and hydrogen temperatures are regulated in the heat exchangers, and the gas humidity control is obtained with a simplified model of the humidifier. The control scheme performance is evaluated for load changes, perturbations and parametric variations, introducing a growing current profile covering a large span of power, and a current profile derived from a standard driving speed cycle. The impact of the control scheme is advantageous, since the control objectives are accomplished and the PEMFC tolerates reasonably membrane damage that can produce active surface reduction. The simulation analysis aids to identify the safe Voltage-Current region, where the compressor works with mechanical stability.

  12. Simulation and Optimization of Air-Cooled PEMFC Stack for Lightweight Hybrid Vehicle Application

    Directory of Open Access Journals (Sweden)

    Jingming Liang

    2015-01-01

    Full Text Available A model of 2 kW air-cooled proton exchange membrane fuel cell (PEMFC stack has been built based upon the application of lightweight hybrid vehicle after analyzing the characteristics of heat transfer of the air-cooled stack. Different dissipating models of the air-cooled stack have been simulated and an optimal simulation model for air-cooled stack called convection heat transfer (CHT model has been figured out by applying the computational fluid dynamics (CFD software, based on which, the structure of the air-cooled stack has been optimized by adding irregular cooling fins at the end of the stack. According to the simulation result, the temperature of the stack has been equally distributed, reducing the cooling density and saving energy. Finally, the 2 kW hydrogen-air air-cooled PEMFC stack is manufactured and tested by comparing the simulation data which is to find out its operating regulations in order to further optimize its structure.

  13. Corrosion kinetics of 316L stainless steel bipolar plate with chromiumcarbide coating in simulated PEMFC cathodic environment

    Directory of Open Access Journals (Sweden)

    N.B. Huang

    Full Text Available Stainless steel with chromium carbide coating is an ideal candidate for bipolar plates. However, the coating still cannot resist the corrosion of a proton exchange membrane fuel cell (PEMFC environment. In this work, the corrosion kinetics of 316L stainless steel with chromium carbide is investigated in simulated PEMFC cathodic environment by combining electrochemical tests with morphology and microstructure analysis. SEM results reveal that the steel’s surface is completely coated by Cr and chromium carbide but there are pinholes in the coating. After the coated 316L stainless steel is polarized, the diffraction peak of Fe oxide is found. EIS results indicate that the capacitive resistance and the reaction resistance first slowly decrease (2–32 h and then increase. The potentiostatic transient curve declines sharply within 2000 s and then decreases slightly. The pinholes, which exist in the coating, result in pitting corrosion. The corrosion kinetics of the coated 316L stainless steel are modeled and accords the following equation: i0 = 7.6341t−0.5, with the corrosion rate controlled by ion migration in the pinholes. Keywords: PEMFC, Metal bipolar plate, Chromium carbide coating, Corrosion kinetics, Pitting corrosion

  14. 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

  15. Development of CH{sub 3}OH fueled PEMFC power plants for hybrid transit buses

    Energy Technology Data Exchange (ETDEWEB)

    Baumert, R; Cooper, R; Feasey, G [DBB Fuel Cell Engines Corp., Poway, CA (United States)

    1999-12-31

    An overview of the methanol fuel cell power system was provided, identifying improved efficiency and reduced emissions as the principal advantages. Four critical tasks regarding on-board fuel processing were described: (1) efficient methanol conversion (steam reforming), (2) effective reformate purification (selective catalytic oxidation), (3) optimized heat integration, and (4) rapid response to transients. A description of a 100 kW PEM fuel cell bus engine package was also presented. As far as a development time table is concerned, the DBB Fuel Cell Engines Corp. of Poway California has completed two methanol fueled PEMFC power plants, fabrication of the initial 100 kW PEMFC engine is in progress and scheduled for delivery by 1998. The two methanol fueled commercial products which are in the planning stages are the 100 and 200 kW class FCPS for hybrid and non-hybrid buses and other applications. tabs., figs.

  16. Propriedades físico-químicas relacionadas ao desenvolvimento de membranas de Nafion® para aplicações em células a combustível do tipo PEMFC Physicochemical properties related to the development of Nafion® membranes for application in fuel cells

    Directory of Open Access Journals (Sweden)

    Carlos E. Perles

    2008-01-01

    Full Text Available Embora não seja tecnologia recente, as células a combustível ou Fuel Cells (FC continuam recebendo grande atenção, pois são consideradas como "fontes de energia do futuro" devido a características como alto rendimento energético e baixa emissão de poluentes, permitindo a extensão o tempo de vida das reservas fósseis e contribuindo para a melhoria da qualidade de vida. Atualmente, as pesquisas estão direcionadas, principalmente, ao desenvolvimento de FC para aplicações em sistemas móveis e portáteis. De todas as tecnologias existentes, a mais promissora para essa finalidade é a célula a combustível de eletrólito polimérico, conhecida como PEMFC (Polymer Electrolyte Fuel Cell cuja pesquisa encontra-se focada, principalmente, no desenvolvimento de membranas poliméricas, com o objetivo de reduzir os custos de produção. Este trabalho será focado nos aspectos físico-químicos do desenvolvimento de membranas poliméricas. Serão discutidos aspectos estruturais do Nafion® relacionado-os as seguintes propriedades físico-químicas: fluxo eletrosmótico, permeabilidade gasosa, transporte de água através da membrana, estabilidade química e térmica. Toda a discussão será realizada para polímeros perfluorados, utilizando o Nafion® como modelo representante dessa classe de polímeros.Fuel Cells (FC continue to receive growing attention, in spite of not being a new technology, for they are considered as the "energy source of the future" owing to characteristics such as high energetic yield and low emission of pollutants. FC technology may lead to a reduction in the negative impact from energy sources on the enviroment, thus improving the quality of life and extending the lifetime of fossil combustible reserves. The mainstream of research in FC is now directed at mobile, portable systems, for which the most promising technology is the Polymer Electrolyte Fuel Cells, also known as PEMFC (Polymer Electrolyte Fuel Cell. Research

  17. Evaluation of the Scaffolding Effect of Pt Nanowires Supported on Reduced Graphene Oxide in PEMFC Electrodes

    Directory of Open Access Journals (Sweden)

    Peter Mardle

    2018-01-01

    Full Text Available The stacking and overlapping effect of two-dimensional (2D graphene nanosheets in the catalyst coating layer is a big challenge for their practical application in proton exchange membrane fuel cells (PEMFCs. These effects hinder the effective transfer of reactant gases to reach the active catalytic sites on catalysts supported on the graphene surface and the removal of the produced water, finally leading to large mass transfer resistances in practical electrodes and poor power performance. In this work, we evaluate the catalytic power performance of aligned Pt nanowires grown on reduced graphene oxide (rGO (PtNW/rGO as cathodes in 16-cm2 single PEMFCs. The results are compared to Pt nanoparticles deposited on rGO (Pt/rGO and commercial Pt/C nanoparticle catalysts. It is found that the scaffolding effect from the aligned Pt nanowire structure reduces the mass transfer resistance in rGO-based catalyst electrodes, and a nearly double power performance is achieved as compared with the Pt/rGO electrodes. However, although a higher mass activity was observed for PtNW/rGO in membrane electrode assembly (MEA measurement, the power performance obtained at a large current density region is still lower than the Pt/C in PEMFCs because of the stacking effect of rGO.

  18. Characterization of self-assembled electrodes based on Au-Pt nanoparticles for PEMFC application

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, E. [Politecnica Univ. de Chiapas, Tuxtla Gutierrez, Chiapas (Mexico). Energia y Sustentabilidad; Sebastian, P.J. [Politecnica Univ. de Chiapas, Chiapas (Mexico). Energia y Sustentabilidad; Centro de Investigacion en Energia, UNAM, Morelos (Mexico); Gamboa, S.A. [Centro de Investigacion en Energia, UNAM, Morelos (Mexico); Pal, U. [Inst. de Fisica, Universidad Autonoma de Puebla Univ., Puebla (Mexico). Inst. de Fisica; Gonzalez, I. [Autonoma Metropolitana Univ. (Mexico). Dept. de Quimica

    2008-07-01

    This paper reported on a study in which membrane electrode assemblies (MEAs) were fabricated by depositing Au, Pt and AuPt nanoparticles on Nafion 115 membrane for use in a proton exchange membrane fuel cell (PEMFC). A Rotating Disc Electrode (RDE) was used to measure the nanoparticle catalyst activity. After deposition of the nanoparticles on the membrane, the surface was studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The membrane proton conduction process was studied by Electrochemical Impedance Spectroscopy (EIS) with the 4 probe technique. The MEAs fabricated with Nafion/Metal membranes were evaluated in a PEMFC under standard conditions. Colloidal solutions were used to prepare self-assembled electrodes with nanoparticles deposited on Nafion membrane. The particles deposited on Nafion showed good stability and had homogeneous distribution along the membrane surface. The impedance results revealed an increase in the membrane proton resistance of the self-assembled electrodes compared to unmodified Nafion. The Au-Pt nanoparticles were obtained by chemical reduction. The nanoparticle size in the three systems was about 2 nm. The self-assembled electrodes performed well in standard conditions. The optimum colloidal concentration and immersion time must be determined in order to obtain good catalytic activity and high membrane conductance. The self-assembled Nafion/AuPt had the best open circuit potential (887 mV). The Au and Pt self-assemblies showed a similar performance in terms of maximum power and maximum current density. The performance of the Nafion/Au self-assembly was influenced more by ohmic losses, particularly in the membrane. The maximum power generation was obtained at 0.35 V. The mass transport losses increased after this value, thereby affecting the efficiency of the PEMFC. 2 figs.

  19. The CO poisoning effect in PEMFCs operational at temperatures up to 200 degrees C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Gao, Ji-An

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts (at a loading of 0.5 mg Pt/cm(2) per electrode! in polymer electrolyte membrane fuel cells (PEMFCs) has been investigated in a temperature range from 125 to 200 degreesC with the phosphoric acid-doped polybenzimidazole membranes...

  20. Effects of bolt pre-loading variations on performance of GDL in a bolted PEMFC by 3-D FEM analysis

    International Nuclear Information System (INIS)

    Chien, Chi-Hui; Hu, Yao-Lun; Su, Ting-Hsuan; Liu, Hsuan-Ting; Wang, Chung-Ting; Yang, Ping-Feng; Lu, Ying-Xu

    2016-01-01

    This study numerically investigated the effects of different bolt pre-loadings on the performance of the gas diffusion layer (GDL) in a bolted proton exchange membrane fuel cell (PEMFC). Firstly, a complete three-dimensional finite element model of a PEMFC bolted by 12 bolts with a reactive area of 5 cm by 5 cm was established using the commercial software SolidWorks. Then, a pre-loading of 1 MPa to 7 MPa on each bolt was applied, increasing in increments 1 MPa, and the corresponding deformation and stress fields of each component of the fuel cell were obtained using the commercial software ANSYS 15.0/Workbench. Finally, the effects of the bolt pre-loading variations on the performance of the GDL were discussed. The results showed that the compression ratio of the GDL increased linearly with the magnitude of bolt pre-loading, and improving the performance of the GDL. However, when the pre-loading on each bolt reached 7 MPa, the compression ratio exceeded 15%, degrading the efficiency of the PEMFC. Also, by comparing the relationships between bolt pre-loading and conductivity and porosity of GDL, in order to obtain the maximum performance of GDL, an optimum value of 4 MPa for bolt preloading was recommended. - Highlights: • Effect of bolt pre-loading on deformations is more serious than that of thermal loading. • Bolt pre-loading improves compression ratio of GDL. • For obtaining a maximum performance of GDL, 4 MPa of bolt pre-loading was recommended. • Flow channel volume reduced by bolt pre-loading degrades the efficiency of PEMFC.

  1. Studies on the efficiency during reactivation of a generation system based on natural gas reformer and a 5 k W fuel cell; Estudos de eficiencia durante reativacao de um sistema de geracao baseado em reformador de gas natural e celula a combustivel de 5 kW

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Francisco da Costa; Furtado, Jose Geraldo de Melo; Silva Junior, Fernando Rodrigues da; Serra, Eduardo Torres [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)]. E-mail: fcl@cepel.br

    2008-07-01

    Fuel cell based power generation systems have been pointing as promising technology for stationary applications mainly to supply power to critical loads. Among several types of fuel cells the Polymer Electrolyte Membrane Fuel Cells (PEMFC) are the main type used around the world. Nowadays reformers are widely employed to produce hydrogen for fuel cells. The Fuel Cell Laboratory of CEPEL has a power plant based on a 5 kW PEMFC and a natural gas reformer. For a long time the PEMFC was inoperable due to reformer malfunctioning and during this time the full power availability of PEMFC was lost due to deactivation of its catalytic sites. In most cases this deactivation is reversible. So it was started a reactivation process aiming to recover the full operational condition of the PEMFC unit. During this process the gas flow relationship and efficiency of the reformer were studied. An analysis of the PEMFC reactivation was conducted where it was noted that the reactivation took place as expected. During the reactivation process the PEMFC and the whole system efficiency were analyzed. The results suggest that the PEMFC can reach efficiency compatible with conventional power generation systems thus allowing PEMFC technology to compete with these energy sources in point of efficiency. (author)

  2. Modeling and optimization of a 1 kWe HT-PEMFC-based micro-CHP residential system

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2012-01-01

    A high temperature-proton exchange membrane (HT-PEMFC)-based micro-combined-heat-and-power (CHP) residential system is designed and optimized, using a genetic algorithm (GA) optimization strategy. The proposed system consists of a fuel cell stack, steam methane reformer (SMR) reactor, water gas...

  3. Extrusion: An environmentally friendly process for PEMFC membrane elaboration

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J.-Y.; Iojoiu, C.; Marechal, M. [LEPMI, UMR 5631 CNRS-INPG-UJF, ENSEEG, BP 75, F-38402, Saint Martin d' Heres (France); Chabert, F.; El Kissi, N. [Rheologie, UMR 5520 CNRS-INPG-UJF, ENSHMG, BP 53, F-38041, Grenoble (France); Salomon, J.; Mercier, R. [LMOPS UMR CNRS 5041, BP 24, F-69390 Vernaison (France); Piffard, Y. [CNRS Universite de Nantes, Institut des Materiaux Jean Rouxel, UMR 6502, BP 32229, F-44322, Nantes Cedex 3 (France); Galiano, H. [CEA, Le Ripault Research Center, BP 16, F-37260, Monts (France)

    2007-12-31

    The paper deals with the use of extrusion to process PEMFC filled and unfilled membranes. Several routes including the sulfonation of filled and unfilled extruded membranes and the extrusion of filled and unfilled ionomers are reported. Thanks to the use of selected water-soluble aid process plasticizers, acid and alkaline forms of sulfonated polyethersulfone were, for the first time, successfully extruded. The extrusion process did not lead to any degradation of the ionomer performances. Decreasing the membrane cost while using environmentally friendly elaboration conditions, it should be helpful to an industrial production. In addition, avoiding filler sedimentation it should allow homogeneous composite membranes to be obtained. (author)

  4. Thermal management of a PEMFC stack by 3D nodal modeling

    Energy Technology Data Exchange (ETDEWEB)

    Dumercy, L.; Glises, R.; Kauffmann, J.M. [Laboratoire de Recherche en Electronique, Electrotechnique et Systemes (L2ES), UFC-UTBM EA 3898, Rue T. MIEG, 90010 Belfort cedex (France); Louahlia-Gualous, H. [FEMTO-ST, CNRS UMR6174, CREST, 2 av. Jean Moulin, 90000 Belfort (France)

    2006-05-19

    This paper describes a 3D thermal modeling by a nodes network model for two PEMFC of 150 and 500W (respectively, 3 and 20 cells). Modeling are realized for each case for one cell before to be integrated on all the stack. Absolute temperatures of H{sub 2}, air and water channels are used as Dirichlet conditions. Temperatures of external surfaces are obtained thanks to an infrared thermographic camera. Final external heat fluxes are deduced from the integrated model. (author)

  5. Investigations on the corrosion resistance of metallic bipolar plates (BPP) in proton exchange membrane fuel cells (PEMFC) - understanding the effects of material, coating and manufacturing

    Science.gov (United States)

    Dur, Ender

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples

  6. Polymer electrolyte membrane fuel cell (PEMFC) flow field plate: design, materials and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, P.J.; Pollet, B.G. [PEM Fuel Cell Research Group, School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom)

    2010-08-15

    This review describes some recent developments in the area of flow field plates (FFPs) for proton exchange membrane fuel cells (PEMFCs). The function, parameters and design of FFPs in PEM fuel cells are outlined and considered in light of their performance. FFP materials and manufacturing methods are discussed and current in situ and ex situ characterisation techniques are described. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  7. Development and testing of the proton exchange membrane fuel cell (PEMFC) for stationary generation; Desenvolvimento e ensaios de uma celula a combustivel de polimero solido (PEMFC) para geracao estacionaria

    Energy Technology Data Exchange (ETDEWEB)

    Ellern, Mara; Boccuzzi, Cyro Vicente [ELETROPAULO, Sao Caetano, SP (Brazil)], e-mail: mara.ellern@aes.com; Ett, Gerhard; Saiki, Gerson Yukio; Janolio, Gilberto [ELECTROCELL, Sao Paulo, SP (Brazil); Jardini, Jose Antonio [Universidade de Sao Paulo (USP), SP (Brazil)

    2004-07-01

    PEM (Proton Exchange Membrane) fuel cell uses a simple chemical reaction to combine hydrogen and oxygen into water, producing electric current in the process. It works something like reversed electrolysis: at the anode, hydrogen molecules give up electrons, forming hydrogen ions (this process is made possible by the platinum catalyst). The proton exchange membrane allows protons to flow through, but not electrons. As a result, the hydrogen ions flow directly through the proton exchange membrane to the cathode, while the electrons flow through an external circuit. As they travel to the cathode through the external circuit, the electrons produce electrical current. At the cathode, the electrons and hydrogen ions combine with oxygen to form water. In a fuel cell, hydrogen's natural tendency to oxidize and form water produces electricity and useful work. No pollution is produced and the only byproducts are water and heat. The huge advance on materials development combined with the growth demand of lower impact on environment is placing the fuel cells on the top of the most promising technologies world-wide. They are becoming in medium term feasible alternatives for energy generators up to energy plants of few MW. (author)

  8. A segmented cell approach for studying the effects of serpentine flow field parameters on PEMFC current distribution

    International Nuclear Information System (INIS)

    Reshetenko, Tatyana V.; Bender, Guido; Bethune, Keith; Rocheleau, Richard

    2013-01-01

    Highlights: ► Effects of a flow field design on PEMFC were investigated. ► A segmented cell was used to study 6- and 10-channel serpentine flow fields. ► 10-Channel flow field improved a fuel cell's performance at high current. ► Performance distribution was more uniform for 10-channel than for 6-channel flow field. ► The performance improvement was due to an increased pressure drop. -- Abstract: A serpentine flow field is a commonly used design in proton exchange membrane fuel cells (PEMFCs). Consequently, optimization of the flow field parameters is critically needed. A segmented cell system was used to study the impact of the flow field's parameters on the current distribution in a PEMFC, and the data obtained were analyzed in terms of voltage overpotentials. 6-Channel and 10-channel serpentine flow field designs were investigated. At low current the segments performance was found to slightly decrease for a 10-channel serpentine flow field. However, increasing the number of channels increased the fuel cell performance when operating at high current and the cell performance became more uniform downstream. The observed improvement in fuel cell performance was attributed to a decrease in mass transfer voltage losses (permeability and diffusion), due to an increased pressure drop. Spatially distributed electrochemical impedance spectroscopy (EIS) data showed differences in the local segment impedance response and confirmed the performance distribution and the impact of the flow field design

  9. Characteristics of the Nafion (registered) - impregnated polycarbonate composite membranes for PEMFCs

    International Nuclear Information System (INIS)

    Kim, Ki-Hwan; Ahn, Sang-Yeoul; Oh, In-Hwan; Ha, Heung Yong; Hong, Seong-Ahn; Kim, Moon-Sun; Lee, Youngkwan; Lee, Yong-Chul

    2004-01-01

    In this work, polycarbonate composite membranes were prepared for proton exchange membrane fuel cells (PEMFCs). In the preparation of membranes, a small amount of poly(ethylene glycol) (PEG) was blended with polycarbonate (PC) solution and then cast to make membranes. PEG contained in the membrane was removed by the high solubility of supercritical CO 2 to afford porosity in the membrane. Then, porous PC membranes were soaked in Nafion (registered) solution to yield the PC/Nafion (registered) composite membranes. The PC composite membrane had lower ion conductivity but higher conductance than Nafion (registered)

  10. Ionic liquids and their hosting by polymers for HT-PEMFC membranes

    Energy Technology Data Exchange (ETDEWEB)

    Hana, M.; Martinez, M.; Cointeaux, L.; Lepretre, J.C. [LEPMI-ELSA, PHELMA, UMR 5631, CNRS, Grenoble INP, UJF, Saint-Martin-d' Heres (France); Molmeret, Y.; El Kissi, N. [Laboratoire de Rheologie, UMR 5520 CNRS-INPG-UJF, ENSHMG, Grenoble (France); Teles, J.; Judeinstein, P. [Institut de Chimie Moleculaire et des Materiaux d' Orsay, CNRS 8182, Orsay (France); Iojoiu, C.; Sanchez, J.Y.

    2010-10-15

    The paper deals with proton-conducting ionic liquids (PCILs) for use, in combination with functional polymers, in membranes operating in high temperature PEMFC. Monoammoniums derived from monoamines and half-neutralised diamines were investigated in the form of triflates. Promising results were obtained with the half-neutralised diamine-based PCIL, its conduction being governed by both Grotthuss-like and vehicular mechanisms, the respective contributions of which depend on temperature. In addition, their blending with Nafion results in a distinct reinforcement of the membrane. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  11. Model development and optimization of operating conditions to maximize PEMFC performance by response surface methodology

    International Nuclear Information System (INIS)

    Kanani, Homayoon; Shams, Mehrzad; Hasheminasab, Mohammadreza; Bozorgnezhad, Ali

    2015-01-01

    Highlights: • The optimization of the operating parameters in a serpentine PEMFC is done using RSM. • The RSM model can predict the cell power over the wide range of operating conditions. • St-An, St-Ca and RH-Ca have an optimum value to obtain the best performance. • The interactions of the operating conditions affect the output power significantly. • The cathode and anode stoichiometry are the most effective parameters on the power. - Abstract: Optimization of operating conditions to obtain maximum power in PEMFCs could have a significant role to reduce the costs of this emerging technology. In the present experimental study, a single serpentine PEMFC is used to investigate the effects of operating conditions on the electrical power production of the cell. Four significant parameters including cathode stoichiometry, anode stoichiometry, gases inlet temperature, and cathode relative humidity are studied using Design of Experiment (DOE) to obtain an optimal power. Central composite second order Response Surface Methodology (RSM) is used to model the relationship between goal function (power) and considered input parameters (operating conditions). Using this statistical–mathematical method leads to obtain a second-order equation for the cell power. This model considers interactions and quadratic effects of different operating conditions and predicts the maximum or minimum power production over the entire working range of the parameters. In this range, high stoichiometry of cathode and low stoichiometry of anode results in the minimum cell power and contrary the medium range of fuel and oxidant stoichiometry leads to the maximum power. Results show that there is an optimum value for the anode stoichiometry, cathode stoichiometry and relative humidity to reach the best performance. The predictions of the model are evaluated by experimental tests and they are in a good agreement for different ranges of the parameters

  12. Chelating agent-assisted heat treatment of a carbon-supported iron oxide nanoparticle catalyst for PEMFC.

    Science.gov (United States)

    Liu, Shyh-Jiun; Huang, Chia-Hung; Huang, Chun-Kai; Hwang, Weng-Sing

    2009-08-28

    Iron complexes were supported on commercial carbon black and heat treated to create FeO(x)/C catalysts that showed a larger normalized current density and normalized power density than commercial Pt/C catalysts; the coordination number of the iron complexes used affected the formation of the active site for oxygen reduction in PEMFC.

  13. Simulation of the catalyst layer in PEMFC based on a novel two-phase lattice model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jiejing; Yang Wei; Xu Li [School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072 (China); Wang Yuxin, E-mail: yxwang@tju.edu.cn [School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072 (China)

    2011-08-01

    Highlights: > We propose a novel two phase lattice model of catalyst layer in PEMFC. > The model features a catalyst phase and a mixed ionomer and pores phase. > Transport and electrochemical reaction in the lattice are simulated. > The model enables more accurate results than pore-solid two phase model. > Profiles of oxygen level and reaction rate across catalyst layer vary with cell current. - Abstract: A lattice model of catalyst layer in proton exchange membrane fuel cells (PEMFCs), consisting of randomly distributed catalyst phase (C phase) and mixed ionomer-pore phase (IP phase), was established by means of Monte Carlo method. Transport and electrochemical reactions in the model catalyst layer were calculated. The newly proposed C-IP model was compared with previously established pore-solid two phase model. The variation of oxygen level and reaction rate along the thickness of catalyst layer with cell current was discussed. The effect of ionomer distribution across catalyst layer was studied by comparing profiles of oxygen level, reaction rate and overpotential, as well as corresponding polarization curves.

  14. Development and Validation of a Simple Analytical Model of the Proton Exchange Membrane Fuel Cell (Pemfc) in a Fork-Lift Truck Power System

    DEFF Research Database (Denmark)

    Hosseinzadeh, Elham; Rokni, Masoud

    2013-01-01

    In this study, a general proton exchange membrane fuel cell (PEMFC) model has been developed in order to investigate the balance of plant of a fork-lift truck thermodynamically. The model takes into account the effects of pressure losses, water crossovers, humidity aspects, and voltage overpotent......In this study, a general proton exchange membrane fuel cell (PEMFC) model has been developed in order to investigate the balance of plant of a fork-lift truck thermodynamically. The model takes into account the effects of pressure losses, water crossovers, humidity aspects, and voltage...

  15. Effects of PEMFC operating parameters on the performance of an integrated ethanol processor

    Energy Technology Data Exchange (ETDEWEB)

    Francesconi, Javier A.; Mussati, Miguel C.; Aguirre, Pio A. [INGAR Instituto de Desarrollo y Diseno (CONICET-UTN), Avellaneda 3657, CP:S3002GJC, Santa Fe (Argentina)

    2010-06-15

    In this paper the performance of a complete fuel cell system processing ethanol fuel has been analyzed as a function of the main fuel cell operating parameters. The fuel processor is based on the steam reforming process, followed by high- and low-temperature shift reactors, and carbon monoxide preferential oxidation reactor, which are coupled to a polymeric fuel cell (PEMFC). The goal was to analyze and improve the fuel cell system performance by simulation techniques. PEMFC operation has been analyzed using an available parametric model, which was implemented within HYSYS environment software. Pinch Analysis concepts were used to investigate the process energy integration and determine the maximum efficiency minimizing ethanol consumption. The system performance was analyzed for the SR-12 Modular PEM Generator, the Ballard Mark V fuel cell and the BCS 500 W stack. The net system efficiency is dependent on the required power demand. Efficiency values higher than 50% at low loads and less than 30% at high power demands are computed. In addition, the effect of fuel cell temperature, pressure and hydrogen utilization was analyzed. The trade-off between the reformer yield and the fuel cell performance defines the optimal operation pressure. The cell temperature determines operating zones where the water, involved in the reforming reactions, can be produced or demanded. (author)

  16. Dynamic analysis of PEMFC-based CHP systems for domestic application

    International Nuclear Information System (INIS)

    Barelli, L.; Bidini, G.; Gallorini, F.; Ottaviano, A.

    2012-01-01

    Highlights: ► Dynamic model of a CHP energy system based on a PEM fuel cell was developed. ► The CHP system behavior at variable electrical and thermal load was investigated. ► The optimal RH value was assessed maximizing PEMFC performance through simulations. ► The system best operating conditions are characterized by a RH value equal to 50%. -- Abstract: Fuel cell-based CHP systems for distributed residential power generation represent an interesting alternative to traditional thermoelectric plants. This is mainly due to the high efficiency obtainable in the production of electricity and heat in a decentralised, quiet and environmental friendly way. The current paper focuses on the development, in Matlab®Simulink environment, of a complete dynamic model of a residential cogenerative (CHP) energy system consisting of the Proton Exchange Membrane fuel cell (PEMFC), fuel processor, heat exchangers, humidifier and auxiliary hot water boiler. The target of the study is the investigation through such a model of the behavior of CHP systems based on fuel cell (FC) at variable electrical and thermal load, in reference to typical load curves of residential users. With the aim to evaluate the system performance (efficiency, fuel consumption, hot water production, response time) and then to characterize its better operating conditions with particular attention to air relative humidity, suitable simulations were carried out. They are characterized by the following of a typical electrical load trend and in relation to two different thermal load profiles. The dynamic model presented in this paper has allowed to observe the fully functioning of the FC based system under variable loads and it has permitted to design appropriate control logics for this system.

  17. Investigation of the internal behavior in segmented PEMFCs of different flow fields during cold start process

    International Nuclear Information System (INIS)

    Lin, R.; Ren, Y.S.; Lin, X.W.; Jiang, Z.H.; Yang, Z.; Chang, Y.T.

    2017-01-01

    In this study, we have researched the internal behavior in segmented proton exchange membrane fuel cells (PEMFCs) with three different flow fields during cold start process. The change of internal current density and temperature in fuel cells with different flow fields could be obviously shown by the printed circuit board (PCB) technology, and the study shows that the flow field is significant for enhancing the cold start ability and durability. Single serpentine flow field has the best cold start performance, while triple channel serpentine flow field has the best uniformity. It is found that without a robust temperature rising tendency, the cell temperature reaching 0 °C does not definitely mean a successful cold start because the cell temperature might drop down 0 °C again. Polarization curves show that there is almost no performance degradation after successful cold start, but the cell degrades quickly after the failed cold start at −7 °C and −10 °C. Based on these characteristics, we optimized the rapid cold start strategy by using electric heating and make it possible to start up the PEMFC at temperatures down to −20 °C within about 11 min. - Highlights: • Segmented fuel cell were used to record the internal current density and temperature distributions during the cold start. • The effects of flow fields on the PEMFC cold start capacity were evaluated. • The effect of cold start on the performance of fuel cell was evaluated. • An optimized strategy was adopted to improve the cold start capacity.

  18. Novel biometric flow slab design for improvement of PEMFC performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chin-Tsan; Hu, Yuh-Chung; Zheng, Pei-Lun [Department of Mechanical and Electro-Mechanical Engineering, Center of Green Technology, National I Lan University, I Lan 26047 (China)

    2010-04-15

    Designing a better flow slab is important to cell performance because of its significant influence on the total pressure drop and flow uniformity. Two novel biometric flow slabs, BFF1 and BFF2, which are addressed in this study, are believed to enhance the capability of oxygen transportation and promote the liquid water removal. Hence, its possession of a higher flow uniformity and lower pressure drop would produce a better power performance than the serpentine and parallel flow. These findings with respect to the design of biometric flow slab could be useful to promote the cell performance of PEMFC, and could even be expanded to other cell types. (author)

  19. Modeling and simulation of a 100 kWe HT-PEMFC subsystem integrated with an absorption chiller subsystem

    DEFF Research Database (Denmark)

    Arsalis, Alexandros

    2012-01-01

    A 100 kWe liquid-cooled HT-PEMFC subsystem is integrated with an absorption chiller subsystem to provide electricity and cooling. The system is designed, modeled and simulated to investigate the potential of this technology for future novel energy system applications. Liquid-cooling can provide...

  20. Modeling and off-design performance of a 1 kWe HT-PEMFC (high temperature-proton exchange membrane fuel cell)-based residential micro-CHP (combined-heat-and-power) system for Danish single-family households

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2011-01-01

    A novel proposal for the modeling and operation of a micro-CHP (combined-heat-and-power) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology is described and analyzed to investigate its commercialization prospects. An HT-PEMFC operates at elevated...... temperatures, as compared to Nafion-based PEMFCs and therefore can be a significant candidate for cogeneration residential systems. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-family household. A complete fuel processing subsystem, with all necessary...

  1. Study and development of membrane electrode assemblies for Proton Exchange Membrane Fuel Cell (PEMFC) with palladium based catalysts; Estudo e desenvolvimento de conjuntos membrana-eletrodos (MEA) para celula a combustivel de eletrolito polimerico condutor de protons (PEMFC) com eletrocatalisadores a base de paladio

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio, Rafael Nogueira

    2013-07-01

    PEMFC systems are capable of generating electricity with high efficiency and low or no emissions, but durability and cost issues prevent its large commercialization. In this work MEA with palladium based catalysts were developed, Pd/C, Pt/C and alloys PdPt/C catalysts with different ratios between metals and carbon were synthesized and characterized. A study of the ratio between catalyst and Nafion Ionomer for formation of high performance triple-phase reaction was carried out, a mathematical model to implement this adjustment to catalysts with different relations between metal and support taking into account the volumetric aspects of the catalyst layer was developed and then a study of the catalyst layer thickness was performed. X-ray diffraction, Transmission and Scanning Electron Microscopy, X-ray Energy Dispersive, Gas Pycnometry, Mercury Intrusion Porosimetry, Gas adsorption according to the BET and BJH equations, and Thermo Gravimetric Analysis techniques were used for characterization and particle size, specific surface areas and lattice parameters determinations were also carried out. All catalysts were used on MEAs preparation and evaluated in 5 cm{sup 2} single cell from 25 to 100 °C at 1 atm and the best composition was also evaluated at 3 atm. In the study of metals for reactions, to reduce the platinum applied to the electrodes without performance losses, Pd/C and PdPt/C 1:1 were selected for anodes and cathodes, respectively. The developed MEA structure used 0,25 mgPt.cm{sup -2}, showing power densities up to 550 mW.cm{sup -2} and power of 2.2 kW{sub net} per gram of platinum. The estimated costs showed that there was a reduction of up to 64.5 %, compared to the MEA structures previously known. Depending on the temperature and operating pressure, values from US$ 1,475.30 to prepare MEAs for each installed kilowatt were obtained. Taking into account recent studies, it was concluded that the cost of the developed MEA is compatible with PEMFC stationary

  2. A fractal model for predicting permeability and liquid water relative permeability in the gas diffusion layer (GDL) of PEMFCs

    Science.gov (United States)

    He, Guangli; Zhao, Zongchang; Ming, Pingwen; Abuliti, Abudula; Yin, Caoyong

    In this study, a fractal model is developed to predict the permeability and liquid water relative permeability of the GDL (TGP-H-120 carbon paper) in proton exchange membrane fuel cells (PEMFCs), based on the micrographs (by SEM, i.e. scanning electron microscope) of the TGP-H-120. Pore size distribution (PSD), maximum pore size, porosity, diameter of the carbon fiber, pore tortuosity, area dimension, hydrophilicity or hydrophobicity, the thickness of GDL and saturation are involved in this model. The model was validated by comparison between the predicted results and experimental data. The results indicate that the water relative permeability in the hydrophobicity case is much higher than in the hydrophilicity case. So, a hydrophobic carbon paper is preferred for efficient removal of liquid water from the cathode of PEMFCs.

  3. The stability of PEMFC electrodes : platinum dissolution vs potential and temperature investigated by quartz crystal microbalance

    NARCIS (Netherlands)

    Dam, V.A.T.; Bruijn, de F.A.

    2007-01-01

    The stability of platinum in proton exchange membrane fuel cell (PEMFC) electrodes has been investigated by determining the dissolution of platinum from a thin platinum film deposited on a gold substrate in 1 M HClO4 at different temperatures ranging between 40 and 80°C and potentials between 0.85

  4. Electrochemical behaviour of PES ionomer and Pt-free catalyst for PEMFCs

    Directory of Open Access Journals (Sweden)

    STEFANIA GIORDANO

    2013-06-01

    Full Text Available Proton Exchange Membrane Fuel Cells (PEMFCs represent promising technologies to the world economy, with many applications and low environmental impact. A most important aspect concerning their widespread implementation is the cost of polymeric membranes, typically perfluorinated membranes and platinum-based catalytic electrode materials, all of which are necessary to promote electrode reactions, thus increasing fuel cell energy efficiency. In this work, we present some data about non-fluorinated polyetheresulphone (PES membranes and Pt-free catalysts, as possible substitutes of the above materials. Their electrochemical behaviour in oxygen reduction reaction in acidic media are investigated and compared with available reference materials.

  5. Impact of Interfacial Water Transport in PEMFCs on Cell Performance

    International Nuclear Information System (INIS)

    Kotaka, Toshikazu; Tabuchi, Yuichiro; Pasaogullari, Ugur; Wang, Chao-Yang

    2014-01-01

    Coupled cell performance evaluation, liquid water visualization by neutron radiography (NRG) and numerical modeling based on multiphase mixture (M2) model were performed with three types of GDMs: Micro Porous Layer (MPL) free; Carbon Paper (CP) with MPL; and CP free to investigate interfacial liquid water transport phenomena in PEMFCs and its effect on cell performance. The visualized results of MPL free GDM with different wettability of bi-polar plates (BPPs) showed hydrophilic BPP improved liquid water transport at the interface between CP and channel. Numerical modeling results indicated that this difference with BPP wettability was caused by the liquid water coverage difference on CP surface. Thus, controlling liquid water coverage is the one of the key strategies for improving cell performance. Additionally, liquid water distributions across the cell for three types of GDMs were compared and significant difference in liquid water content at the interface between Catalyst Layer (CL) and GDM was observed. Numerical modeling suggests this difference is influenced by the gap at the interface and that the MPL could minimize this effect. The CP free cell (i.e. only MPL) showed the best performance and the lowest liquid water content. There were multiple impacts of interfacial liquid water transport both at CL-GDM and GDM-channel interfaces. High hydrophobicity and fine structure of MPLs contributed to enhanced liquid water transport at GDM-channel interface and as a result reduced the liquid water coverage. At the same time, MPL improves contact at the CL-GDM interface in the same manner as seen in CP with MPL case. Thus, the CP free concept showed the best performance. It is suggested that the design of the interface between each component of the PEMFC has a great impact on cell performance and plays a significant role in achievement of high current density operation and cost reduction in FCEVs

  6. Optimization of Ru{sub x}Se{sub y} electrocatalyst loading for oxygen reduction in a PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Huerta, R.G. [Instituto Politecnico Nacional, Laboratorio de Electroquimica y Corrosion ESIQIE, UPALP, 07738 Mexico, D.F., Mexico (Mexico); Guzman-Guzman, A.; Solorza-Feria, O. [Depto. Quimica, Centro de Investigacion y de Estudios Avanzados del IPN, A. Postal 14-740, 07360 Mexico D.F., Mexico (Mexico)

    2010-11-15

    The synthesis, characterization and optimization of Ru{sub x}Se{sub y} catalyst loading as a cathode electrode for a single polymer electrolyte membrane fuel cell, PEMFC were investigated. Ru{sub x}Se{sub y} catalyst was synthesized via a decarbonylation of Ru{sub 3}(CO){sub 12} and elemental selenium in 1,6-hexanediol under refluxing conditions for 2 h. The powder electrocatalyst was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and examined for the oxygen reduction reaction (ORR) in 0.5M H{sub 2}SO{sub 4} by rotating disk electrode (RDE) and in membrane-electrode assemblies, MEAs for a single PEMFC. Results indicate the formation of agglomerates of crystalline particles with nanometric size embedded in an amorphous phase. The catalyst exhibited high current density and lower overpotential for the ORR compared to that of Ru{sub x} cluster catalyst. Dispersed Ru{sub x}Se{sub y} catalyst loading on Vulcan carbon was optimized as a cathode electrode by performance testing in a single H{sub 2}-O{sub 2} fuel cell. (author)

  7. Integrated automation system for a pilot plant for energy conversion using PEMFCs

    International Nuclear Information System (INIS)

    Culcer, Mihai; Iliescu, Mariana; Raceanu, Mircea; Stanciu, Vasile; Stefanescu, Ioan; Enache, Adrian; Lazaro, Pavel Gabriel; Lazaroiu, Gheorghe; Badea, Adrian

    2007-01-01

    Based on Hydrogen and Fuel Cells researches and technological capabilities achieved in the National R and D Programs, ICIT Rm. Valcea built an experimental-demonstrative pilot plant for energy conversion using hydrogen PEMFCs. This pilot plant consists of a fuel processor based on steam methane reforming (SMR) process, a hydrogen purification unit, a PEM fuel cells stack (FCS) and a power electronics unit. The paper deals with the dedicated controlling system that provides automated data acquisition, manual or on-line operational control, gas management, humidification, temperature and flow controls. (authors)

  8. Internal currents in PEMFC during start-up or shut-down

    Energy Technology Data Exchange (ETDEWEB)

    Maranzana, G.; Lottin, O.; Moyne, C.; Dillet, J.; Lamibrac, A.; Mainka, J.; Didierjean, S. [Nancy Univ. - CNRS (France). LEMTA

    2010-07-01

    Experiments show that the internal currents that occur during PEMFC start-up can reach up to 1 Acm{sup -2}. This is far more important than the expected order of magnitude of the current densities associated with carbon oxidation, which is only of a few mAcm{sup -2}. The predominant phenomenon that explains the internal currents is the charge and discharge of the double layer capacitances. A simple model with constant values of the electric parameters yields numerical results close to the experimental ones. It also explains the transient voltage rise (over the steady state open circuit voltage) that is sometimes observed experimentally shortly after the fuel cell start up. (orig.)

  9. Platinum-TM (TM = Fe, Co) alloy nanoparticles dispersed nitrogen doped (reduced graphene oxide-multiwalled carbon nanotube) hybrid structure cathode electrocatalysts for high performance PEMFC applications.

    Science.gov (United States)

    Vinayan, B P; Ramaprabhu, S

    2013-06-07

    The efforts to push proton exchange membrane fuel cells (PEMFC) for commercial applications are being undertaken globally. In PEMFC, the sluggish kinetics of oxygen reduction reactions (ORR) at the cathode can be improved by the alloying of platinum with 3d-transition metals (TM = Fe, Co, etc.) and with nitrogen doping, and in the present work we have combined both of these aspects. We describe a facile method for the synthesis of a nitrogen doped (reduced graphene oxide (rGO)-multiwalled carbon nanotubes (MWNTs)) hybrid structure (N-(G-MWNTs)) by the uniform coating of a nitrogen containing polymer over the surface of the hybrid structure (positively surface charged rGO-negatively surface charged MWNTs) followed by the pyrolysis of these (rGO-MWNTs) hybrid structure-polymer composites. The N-(G-MWNTs) hybrid structure is used as a catalyst support for the dispersion of platinum (Pt), platinum-iron (Pt3Fe) and platinum-cobalt (Pt3Co) alloy nanoparticles. The PEMFC performances of Pt-TM alloy nanoparticle dispersed N-(G-MWNTs) hybrid structure electrocatalysts are 5.0 times higher than that of commercial Pt-C electrocatalysts along with very good stability under acidic environment conditions. This work demonstrates a considerable improvement in performance compared to existing cathode electrocatalysts being used in PEMFC and can be extended to the synthesis of metal, metal oxides or metal alloy nanoparticle decorated nitrogen doped carbon nanostructures for various electrochemical energy applications.

  10. Integration of autothermal diesel reformer for hydrogen production feeding a PEMFC; Integracion de reformador diesel con pilas de combustible tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, F. I.; Briceno, Y. B.; Navarro, R. M.; Alvarez, C.; Bordons, C.

    2004-07-01

    This paper presents carried out actions to design and construct an autothermal diesel reformer for hydrogen production feeding a PEMFC.These activities have been performed by INTA, AICIA, CIDAUT and ICP-CSIC trough a collaborative effort 50% funded by INTA and by partners as in kind contributions as a function of developed tasks.The paper presents activities carried out to date: selection of a catalyst, simulation of the process, design and construction of a 5 kW autothermal diesel reformer. Reformer will be characterized during the second half of 2004 and, finally, will be installed for a proper operation together with a 5 kW PEMFC at the promises of INTA located in Centro de Experimentacion de Arenosillo at Huelva. (Author)

  11. Optimization of a High Temperature PEMFC micro-CHP System by Formulation and Application of a Process Integration Methodology

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2013-01-01

    A 1 kWe micro combined heat and power (CHP) system based on high temperature proton exchange membrane fuel cell (PEMFC) technology is modeled and optimized by formulation and application of a process integration methodology. The system can provide heat and electricity for a singlefamily household...

  12. Evaluation and characterization of ceramic membranes based on Pdms/SiC containing phosphotungstic acid as electrolytes for PEM-FC; Avaliacao e caracterizacao de membranas ceramicas condutoras a base de PDMS/SiC contendo acido fosfotungstico como eletrolito para PEM-FC

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Marcelo de Oliveira; Guimaraes, Danilo Hansen; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Barbosa, Diego Augusto Batista; Paschoal, Carlos William de Araujo [Universidade Federal do Maranhao (DF/UFMA), Sao Luis, MA (Brazil). Dept. de Fisica; Almeida, Rafael Mendonca; Tanaka, Auro Atsushi [Universidade Federal do Maranhao (DQ/UFMA), Sao Luis, MA (Brazil). Dept. de Quimica

    2009-07-01

    This work presents the development of membranes with potential use in Proton Exchange Fuel Cells (PEM-FC), consisting of hybrid materials based on poly(dimethylsiloxane), crosslinked with tetraethyl orthosilicate (TEOS), and reinforced with silicon carbide and phosphotungstic acid. The membrane series PDMS/TEOS/SiC/PWA were prepared by the reaction of PDMS and TEOS, 70/30% proportions in mass, catalyzed by dibutyltin dilaurate. SiC was incorporated in a 25% proportion, and PWA in varied proportions (5, 10, 15 and 20%), by weight. The membranes were characterized by Thermo-Gravimetric Analysis (TGA), X-ray Diffraction, Scanning Electron Microscopy and impedance spectroscopy. SiC and PWA addition to the membrane increased both structure organization and material crystallinity. The insertion of PWA provided an increase in the conductivity. However, maximum conductivity was obtained with concentration levels above 10%. The insertion of SiC associated with the PWA did not influence the conductivity for concentrations between 10 and 20%. (author)

  13. Humidifying system design of PEMFC test platform based on the mixture of dry and wet air

    Directory of Open Access Journals (Sweden)

    Tiancai Ma

    2015-01-01

    Full Text Available Based on the present humidifying system of PEMFC test platform, a novel design based on dry and wet air mixture is proposed. Key parameters are calculated, and test platform is built. Three experiments are implemented to test the performance of proposed design. Results show that the new design can meet the requirements, and realize the quick response and accurate control.

  14. Study of thermal management in water-cooled PEMFC%水冷型PEMFC的热管理研究

    Institute of Scientific and Technical Information of China (English)

    朱柳; 朱新坚; 沈海峰

    2012-01-01

    质子交换膜燃料电池(PEMFC)电堆内气、水两相的分布和热量的产生与传递间相互影响.为提高电堆的性能和寿命,根据连续方程和质量守恒定律,建立了电堆内气、水两相传输的动态模型;根据能量守衡原理,建立了PEMFC电堆温度和冷却水温度的动态模型;并在此基础上采用李雅普诺夫函数反向递推法设计了—种非线性鲁棒控制器,使系统温度能在一定摄动范围内保持稳定.最后,在Matlab/Simulink平台上验证了该模型及控制策略的有效性.%The distributions of gas and liquid water, thermal generation and transferring are interacting with each other dosely in proton exchange membrane fuel cell (PEMFC). According to the continuity equation and law of mass conservation, a dynamic model of two-phase (gas and liquid water) transmission in PEMFC was established; and on the basis of energy conservation theory, models of stack temperature and cooling water temperature were developed; what's more, based on these foregoing models, a nonlinear robust controller was proposed by adopting the method of Lyapunov function reverse recursion. Finally, the effectiveness and robustness of the whole model and control strategies were verified on the platform of Matlab/Simulink.

  15. A method for the ad hoc and real-time determination of the water balance in a PEMFC

    DEFF Research Database (Denmark)

    Berning, Torsten

    2014-01-01

    anemometry, and this method provides a voltage signal that can be fed to the board computer of a fuel cell vehicle for PEMFC diagnosis. It is also shown that the nitrogen cross-over from cathode to anode has only a small effect on the anode outlet velocity. In addition to detecting the velocity, the relative...

  16. Measurement of polarization curve and development of a unique semi-empirical model for description of PEMFC and DMFC performances

    Directory of Open Access Journals (Sweden)

    M. SHAKERI

    2011-06-01

    Full Text Available In this study, a single polymer electrolyte membrane fuel cell (PEMFC in H2/ /O2 form with an effective dimension of 5 cm5 cm as well as a single direct methanol fuel cell (DMFC with a dimension of 10 cm10 cm were fabricated. In an existing test station, the voltage-current density performances of the fabricated PEMFC and DMFC were examined under various operating conditions. As expected, DMFC showed a lower electrical performance which can be attributed to the slower methanol oxidation rate in comparison to the hydrogen oxidation. The results obtained from the cell operation indicated that the temperature has a great effect on the cell performance. At 60 C, the best power output was obtained for PEMFC. There was a drop in the cell voltage beyond 60 C, which can be attributed to the reduction of water content inside the membrane. For DMFC, the maximum power output resulted at 64 C. Increasing oxygen stoichiometry and total cell pressure had a marginal effect on the cell performance. The results also revealed that the cell performance improved by increasing pressure differences between the anode and cathode. A unified semi-empirical thermodynamic based model was developed to describe the cell voltage as a function of current density for both kinds of fuel cells. The model equation parameters were obtained through a nonlinear fit to the experimental data. There was a good agreement between the experimental data and the model predicted cell performance for both types of fuel cells.

  17. A review on water fault diagnosis of PEMFC associated with the pressure drop

    International Nuclear Information System (INIS)

    Pei, Pucheng; Li, Yuehua; Xu, Huachi; Wu, Ziyao

    2016-01-01

    Highlights: • Reviewed the effect factors and estimations of pressure drop associated with water fault diagnosis. • Reviewed pressure drop-based water fault diagnosis using different indicators. • Deviation of pressure drop is used frequently to diagnose water fault. • Reviewed recovery strategies based on pressure drop used in commercial PEMFC. • Merits, demerits and application prospects of pressure drop-based water fault diagnosis are discussed. - Abstract: The pressure difference between the inlet and outlet of the reactant in fuel cells is called the pressure drop, which is related to the water amount inside the fuel cells. In recent years there have been many studies that used the pressure drop to detect the water content and diagnose water fault of proton exchange membrane fuel cells (PEMFCs). To our knowledge, there has not been a systematic review of these studies. In this paper, the effect variables of pressure drop are reviewed firstly. Then estimations of the theoretical pressure drop are reviewed mainly based on the following four aspects: Bernoulli’s equation, two-phase flow multiplier, Darcy’s law and artificial intelligence. Afterward, the water fault diagnosis based on the pressure drop using the following six indicators are reviewed: indicator of direct pressure drop, its deviation, frequency, multiplier, the ratio of pressure drop to flow rate and the flooding degree. In addition, the strategies of water fault recovery are also summarized. Finally the merits, demerits and application prospects of pressure drop-based water fault diagnosis are presented.

  18. Swelling behavior of PEMFC during conditioning

    Directory of Open Access Journals (Sweden)

    J. Parrondo

    2007-09-01

    Full Text Available Polymeric cation exchange membranes (PEMFC are used in fuel cell technology. These membranes act as a physical barrier between anode and cathode, but diffusion through the membrane should allow protons to be carried from anode to cathode at a rate sufficient to supply energy requirements. They avoid any direct reaction of oxygen and hydrogen that would diminish fuel cell efficiency. Membranes have to be conditioned before use. This conditioning step changes membrane counterions and modifies their water content, which has an effect on their diffusion coefficients. In order to analyse and quantify the effect of conditioning techniques on membrane performance various experiments with Nafion 117 cation exchange membranes were carried out. Membranes were conditioned using various methods to change the charged cation in the membrane. The reactives used were ultrapure water, nitric acid, hydrochloric acid, hydrogen peroxide, sodium chloride, potassium chloride and ethylene glycol, all at room temperature. Some conditioning methods were carried out using solvents heated to 100 ºC. Water content was indirectly monitored by measuring membrane swelling. Results show that membrane conditioning with strong acids followed by treatment with water increases membrane water content by about 5%. Using high-temperature treatment the water content also increases. Water uptake or release from membranes is analysed in terms of water activity.

  19. Fundamental understanding of liquid water effects on the performance of a PEMFC with serpentine-parallel channels

    International Nuclear Information System (INIS)

    Le, Anh Dinh; Zhou Biao

    2009-01-01

    A three-dimensional and unsteady proton exchange membrane fuel cell (PEMFC) model with serpentine-parallel channels has been incorporated to simulate not only the fluid flow, heat transfer, species transport, electrochemical reaction, and current density distribution but also the behaviors of liquid water in the gas-liquid flow of the channels and porous media. Using this general model, the behaviors of liquid water were investigated by performing the motion, deformation, coalescence and detachment of water droplets inside the channels and the penetration of liquid through the porous media at different time instants. The results showed that: tracking the interface of liquid water in a reacting gas-liquid flow in PEMFC can be fulfilled by using volume-of-fluid (VOF) algorithm combined with solving the conservation equations of continuity, momentum, energy, species transport and electrochemistry; the presence of liquid water in the channels has a significant impact on the flow fields, e.g., the gas flow became unevenly distributed due to the blockage of liquid water where the high pressure would be suddenly built up and the reactant gas transport in the channels and porous media would be hindered by liquid water occupation

  20. Graphitized Carbon: A Promising Stable Cathode Catalyst Support Material for Long Term PEMFC Applications.

    Science.gov (United States)

    Mohanta, Paritosh Kumar; Regnet, Fabian; Jörissen, Ludwig

    2018-05-28

    Stability of cathode catalyst support material is one of the big challenges of polymer electrolyte membrane fuel cells (PEMFC) for long term applications. Traditional carbon black (CB) supports are not stable enough to prevent oxidation to CO₂ under fuel cell operating conditions. The feasibility of a graphitized carbon (GC) as a cathode catalyst support for low temperature PEMFC is investigated herein. GC and CB supported Pt electrocatalysts were prepared via an already developed polyol process. The physical characterization of the prepared catalysts was performed using transmission electron microscope (TEM), X-ray Powder Diffraction (XRD) and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis, and their electrochemical characterizations were conducted via cyclic voltammetry(CV), rotating disk electrode (RDE) and potential cycling, and eventually, the catalysts were processed using membrane electrode assemblies (MEA) for single cell performance tests. Electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SEM) have been used as MEA diagonostic tools. GC showed superior stability over CB in acid electrolyte under potential conditions. Single cell MEA performance of the GC-supported catalyst is comparable with the CB-supported catalyst. A correlation of MEA performance of the supported catalysts of different Brunauer⁻Emmett⁻Teller (BET) surface areas with the ionomer content was also established. GC was identified as a promising candidate for catalyst support in terms of both of the stability and the performance of fuel cell.

  1. Low cost PEMFC generator manufacturing line. The competitiveness and trustability strategy

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Valdemar Stelita; Souza, Adler de; Ferreira, Mauricio S. [NovoCell Energy Systems S.A., Santa Barbara D' Oeste, SP (Brazil)], Email: valdemar.stelita@novocell.ind.br; Muschellack, Erich [Idee Technologies Ltda, Sao Paulo, SP (Brazil)

    2010-07-01

    Concepts of Lean Manufacturing Lines for Polymer Electrolyte Membrane Fuel Cells (PEMFC) have been searched for the last twenty years, with no fully success so far. As this is considered around the world the last barrier to spread the hydrogen economy for universities and science institutions to the normal life of people, we at NovoCell decided six years ago to develop and test all key aspects that can help making it by a 'Low Cost, Feasible and Reliable Production Process'. The present work is a demonstration of the results we achieved, the main characteristics of the prototypes produced from the lines and that will be the base for our commercial operation starting next year. (author)

  2. Low cost PEMFC generator manufacturing line. The competitiveness and trustability strategy

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Valdemar Stelita; Souza, Adler de; Ferreira, Mauricio S. [NovoCell Energy Systems S.A., Santa Barbara D' Oeste, SP (Brazil)], Email: valdemar.stelita@novocell.ind.br; Muschellack, Erich [Idee Technologies Ltda, Sao Paulo, SP (Brazil)

    2010-07-01

    Concepts of Lean Manufacturing Lines for Polymer Electrolyte Membrane Fuel Cells (PEMFC) have been searched for the last twenty years, with no fully success so far. As this is considered around the world the last barrier to spread the hydrogen economy for universities and science institutions to the normal life of people, we at NovoCell decided six years ago to develop and test all key aspects that can help making it by a 'Low Cost, Feasible and Reliable Production Process'. The present work is a demonstration of the results we achieved, the main characteristics of the prototypes produced from the lines and that will be the base for our commercial operation starting next year. (author)

  3. Development of electrode-membrane-electrode assemblies for proton exchange membrane fuel cells (PEMFC) by Sieve printing; Desenvolvimento de conjuntos eletrodo-membrana-eletrodo para celulas a combustivel a membrana trocadora de protons (PEMFC) por impressao a tela

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Alexandre Bodart de

    2008-07-01

    The Sieve Printing process was studied in this work to apply the catalyst layers onto electrolytes utilized in PEMFC. Initially, 25 cm{sup 2} active area MEAs were built for comparison with others MEAs produced by the Spray technique. The two methods produced MEAs that showed current densities higher than 600 mA.cm{sup -2} at 600 mV. A scaling up study for 144 cm{sup 2} of active area MEAs was carried out. For this purpose, a new cell had to be projected for shelter the MEAs in such dimensions. The profile of the gas distribution channels was developed through the computational fluid dynamic tool 'Comsol Multiphysics'. For the design of the bipolar plates of the cell the 'Auto CAD' was used. The 144 cm{sup 2} MEAs made by Spray and by Sieve Printing methods were confronted with commercials MEAs ones of equal dimensions. These commercials MEAs presented better performance at 600 mV, however they were more costly than the solution developed in this study. The new method was showed to be adequate to fabricate low cost MEAs of different geometries and to produce any amount of MEAs for small scale stacks (up to 10 kW). (author)

  4. Development of electrode-membrane-electrode assemblies for proton exchange membrane fuel cells (PEMFC) by Sieve printing; Desenvolvimento de conjuntos eletrodo-membrana-eletrodo para celulas a combustivel a membrana trocadora de protons (PEMFC) por impressao a tela

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Alexandre Bodart de

    2008-07-01

    The Sieve Printing process was studied in this work to apply the catalyst layers onto electrolytes utilized in PEMFC. Initially, 25 cm{sup 2} active area MEAs were built for comparison with others MEAs produced by the Spray technique. The two methods produced MEAs that showed current densities higher than 600 mA.cm{sup -2} at 600 mV. A scaling up study for 144 cm{sup 2} of active area MEAs was carried out. For this purpose, a new cell had to be projected for shelter the MEAs in such dimensions. The profile of the gas distribution channels was developed through the computational fluid dynamic tool 'Comsol Multiphysics'. For the design of the bipolar plates of the cell the 'Auto CAD' was used. The 144 cm{sup 2} MEAs made by Spray and by Sieve Printing methods were confronted with commercials MEAs ones of equal dimensions. These commercials MEAs presented better performance at 600 mV, however they were more costly than the solution developed in this study. The new method was showed to be adequate to fabricate low cost MEAs of different geometries and to produce any amount of MEAs for small scale stacks (up to 10 kW). (author)

  5. A three-dimensional numerical investigation of trapezoid baffles effect on non-isothermal reactant transport and cell net power in a PEMFC

    International Nuclear Information System (INIS)

    Perng, Shiang-Wuu; Wu, Horng-Wen

    2015-01-01

    Highlights: • We study how angle and height of trapezoid baffle affect PEMFC net power. • The jet-type, trapping, and blockage effects augment non-isothermal transport in flow channel. • Greater angles and heights of trapezoid baffles provide more reactant to the catalyst layer. • Baffles of 1.5 mm and 90° fully block flow channel to show bad heat transfer and large pressure drop. • Maximum enhancement of cell net power is 90% with baffles of 60° angle and 1.125 mm height. - Abstract: The present study performed a three-dimensional numerical simulation to observe how trapezoid baffles affect non-isothermal reactant transports and cell net power in the proton exchange membrane fuel cell (PEMFC) by the SIMPLE-C method. The geometric parameters of trapezoid baffles installed in the gas channel employed in this study include the angle and height with the same gas diffusion and catalyst layers to realize the cell net power considering the effect of liquid water formation on the fluid flow field. The cell net power is adopted to evaluate the real enhancement of cell performance due to the additional pumping power induced by the pressure loss through the PEMFC. The results illustrated that compared with traditional gas channel without baffles, the novel gas channel with trapezoid baffles, whose angle is 60° and height is 1.125 mm, enhances the cell net power best by approximately 90% among all trapezoid baffle designs

  6. Development of a membrane electrode assembly production process for proton exchange membrane fuel cell (PEMFC) by sieve printing

    International Nuclear Information System (INIS)

    Bonifacio, Rafael Nogueira

    2010-01-01

    Energy is a resource that presents historical trend of growth in demand. Projections indicate that future energy needs will require a massive use of hydrogen as fuel. The use of systems based on the use of proton exchange membrane fuel cell (PEMFC) has features that allow its application for stationary applications, automotive and portable power generation. The use of hydrogen as fuel for PEMFC has the advantage low pollutants' emission, when compared to fossil fuels. For the reactions in a PEMFC is necessary to build membrane electrode assembly (MEA). And the production of MEAs and its materials are relevant to the final cost of kW of power generated by systems of fuel cell. This represent currently a technological and financial barriers to large-scale application of this technology. In this work a process of MEAs fabrication were developed that showed high reproducibility, rapidity and low cost by sieve printing. The process of sieve printing and the ink composition as a precursor to the catalyst layer were developed, which allow the preparation of electrodes for MEAs fabrication with the implementation of the exact catalyst loading, 0.6 milligrams of platinum per square centimeters (mgPt.cm -2 ) suitable for cathodes and 0.4 mgPt.cm -2 for anode in only one application step per electrode. The ink was developed, produced, characterized and used with similar characteristics to ink of sieve printing build for other applications. The MEAs produced had a performance of up to 712 mA.cm -2 by 600 mV to 25 cm 2 MEA area. The MEA cost production for MEAs of 247.86 cm 2 , that can generate 1 kilowatt of energy was estimated to US$ 7,744.14 including cost of equipment, materials and labor. (author)

  7. A concise guide to sustainable PEMFCs: recent advances in improving both oxygen reduction catalysts and proton exchange membranes.

    Science.gov (United States)

    Scofield, Megan E; Liu, Haiqing; Wong, Stanislaus S

    2015-08-21

    The rising interest in fuel cell vehicle technology (FCV) has engendered a growing need and realization to develop rational chemical strategies to create highly efficient, durable, and cost-effective fuel cells. Specifically, technical limitations associated with the major constituent components of the basic proton exchange membrane fuel cell (PEMFC), namely the cathode catalyst and the proton exchange membrane (PEM), have proven to be particularly demanding to overcome. Therefore, research trends within the community in recent years have focused on (i) accelerating the sluggish kinetics of the catalyst at the cathode and (ii) minimizing overall Pt content, while simultaneously (a) maximizing activity and durability as well as (b) increasing membrane proton conductivity without causing any concomitant loss in either stability or as a result of damage due to flooding. In this light, as an example, high temperature PEMFCs offer a promising avenue to improve the overall efficiency and marketability of fuel cell technology. In this Critical Review, recent advances in optimizing both cathode materials and PEMs as well as the future and peculiar challenges associated with each of these systems will be discussed.

  8. Optimisation of the microporous layer for a polybenzimidazole-based high temperature PEMFC - effect of carbon content

    Energy Technology Data Exchange (ETDEWEB)

    Lobato, J.; Canizares, P.; Rodrigo, M.A.; Ubeda, D.; Pinar, F.J.; Linares, J.J. [Department of Chemical Engineering, University of Castilla-La Mancha, Av. Camilo Jose Cela, n 12. 13071, Ciudad Real (Spain)

    2010-10-15

    This work aims at studying the role of the microporous layer (MPL) in electrodes prepared for high temperature PBI-based PEMFC. The two main components of this layer are carbon black and a polymeric binder (Teflon). This work addresses the effect of the MPL carbon amount on the performance of a high temperature PEMFC. Thus, gas diffusion layers (GDLs) containing MPL with different carbon contents (from 0.5 to 4 mg cm{sup -2}) were prepared. Firstly, they were physically characterised by Hg-porosimetry measuring pore size distribution, porosity, tortuosity and mean pore size. Permeability measurements were also performed. The higher the carbon content was the lower both porosity and permeability were. Afterwards, electrodes were prepared with these GDLs and were electrochemically characterised. Electrochemical surface area (ESA) was determined and fuel cell performance was evaluated under different fuel and comburent stoichiometries, supporting these results with impedance spectra. This made it possible to see the benefits of the MPL inclusion in the electrode structure, with a significant increase in the fuel cell performance and ESA. Once the goodness of the MPL was confirmed, result analysis led to an optimum MPL composition of 2 mg cm{sup -2} of carbon for both electrodes, anode and cathode. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Numerical simulation for rib and channel position effect on PEMFC performances

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhixiang; Wang, Cheng; Mao, Zongqiang [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Zhang, Haiyong [Lab of Sail, Cable and Paints, Navy Equipment Technology Institute, Beijing, 102442 (China)

    2010-04-15

    Simulation is an important method for engineers to probe the detailed transportation and reaction information inside fuel cells and guide their designs without large amount of experiments. Although many papers discussing fuel cell flow fields design could be found in documents, relative positions of the ribs and channels in the anode and cathode flow field plates haven't been paid attention to surprisingly. In this paper, simulation results were given to explain the influences of relative positions of the ribs and channels in the anode and cathode flow field plates on the proton exchange membrane fuel cell (PEMFC) performances. It is interesting that the influence differs with several factors and the information will be helpful for fuel cell design. (author)

  10. Evaluation of the corrosion resistance of Ni-Co-B coatings in simulated PEMFC environment

    Energy Technology Data Exchange (ETDEWEB)

    Gamboa, S.A.; Valenzuela, E.; Sebastian, P.J. [CIE-UNAM, 62580 Temixco, Morelos (Mexico); Gonzalez-Rodriguez, J.G. [UAEM-CIICAp, Av. Universidad 1001, Col. Chamilpa, 62210 Cuernavaca, Mor. (Mexico); Campillo, B. [Facultad de Quimica-UNAM, Cd. Universitaria, DF, CP 04510 (Mexico); Reyes-Rojas, A. [CIMAV, Miguel de Cervantes 120, Complejo Ind. Chihuahua, 31109 Chihuahua, Chih. (Mexico)

    2006-05-20

    The corrosion resistance behavior of Ni-Co-B coated carbon steel, Al 6061 alloy and 304 stainless steel was evaluated in simulated proton exchange membrane fuel cell (PEMFC) environment. The phase structure of the NiCoB based alloy was determined by Rietveld analysis. The PEMFC environment was constituted of 0.5M H{sub 2}SO{sub 4} at 60{sup o}C and the evaluation techniques employed included potentiodynamic polarization, linear polarization resistance, open circuit potential measurements and electrochemical impedance spectroscopy. The results showed that in all cases the corrosion resistance of the Ni-Co-B coating was higher than that of the uncoated alloys; about two orders of magnitude with respect to carbon steel and an order of magnitude compared to 304 stainless steel. Except for the uncoated 304 type stainless steel, the polarization curves for the coated specimens did not exhibit a passive region but only anodic dissolution. The corrosion potential value, E{sub corr}, was always nobler for the coated samples than for the uncoated specimens. This was true for the stainless steel in the passive region, but in the active state for the carbon steel and Al 6061 alloy. The corrosion of the underlying alloy occurred due to filtering of the solution through coating defects like microcracks, pinholes, etc. During the filtering process the E{sub corr} value of the coating decreased slowly until it reached a steady state value, close to the E{sub corr} value of the underlying alloy. (author)

  11. Influence of Sintering Temperature on Mechanical and Physical properties of Mill Scale based Bipolar Plates for PEMFC

    Science.gov (United States)

    Khaerudini, Deni S.; Berliana, Rina; Prakoso, Gatra B.; Insiyanda, Dita R.; Alva, Sagir

    2018-03-01

    This work concerns the utilization of mill scale, a by-product of iron and steel formed during the hot rolling of steel, as a potential material for use as bipolar plates in proton exchange membrane fuel cells (PEMFCs). On the other hand, mill scale is considered a very rich in iron source having characteristic required such as for current collector in bipolar plate and would significantly contribute to lower the overall cost of PEMFC based fuel cell systems. In this study, the iron reach source of mill scale powder, after sieving of 150 mesh, was mechanically alloyed with the aluminium source containing 30 wt.% using a shaker mill for 3 h. The mixed powders were then pressed at 300 MPa and sintered at various temperatures of 400, 450 and 500 °C for 1 h under inert gas atmosphere. The structural changes of powder particles during mechanical alloying and after sintering were studied by x-ray diffractometry, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), microhardness measurement, and density - porosity analysis. The details of the performance variation of three different sintering conditions can be preliminary explained by the metallographic and crystallographic structure and phase analysis as well as sufficient mechanical strength of the sintered materials was presented in this report.

  12. Thermal and electrical energy management in a PEMFC stack - An analytical approach

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyan, S.; Jayakumar, K.; Rajalakshmi, N.; Dhathathreyan, K.S. [Centre for Fuel Cell Technology, ARC International (ARCI), 120, Mambakkam Main Road, Medavakkam, Chennai 601 302 (India)

    2008-02-15

    An analytical method has been developed to differentiate the electrical and thermal resistance of the PEM fuel cell assembly in the fuel cell operating conditions. The usefulness of this method lies in the determination of the electrical resistance based on the polarization curve and the thermal resistance from the mass balance. This method also paves way for the evaluation of cogeneration from a PEMFC power plant. Based on this approach, the increase in current and resistance due to unit change in temperature at a particular current density has been evaluated. It was observed that the internal resistance of the cell is dependent on the electrode fabrication process, which also play a major role in the thermal management of the fuel cell stack. (author)

  13. La-doped Al2O3 supported Au nanoparticles: highly active and selective catalysts for PROX under PEMFC operation conditions.

    Science.gov (United States)

    Lin, Qingquan; Qiao, Botao; Huang, Yanqiang; Li, Lin; Lin, Jian; Liu, Xiao Yan; Wang, Aiqin; Li, Wen-Cui; Zhang, Tao

    2014-03-14

    La-doped γ-Al2O3 supported Au catalysts show high activity and selectivity for the PROX reaction under PEMFC operation conditions. The superior performance is attributed to the formation of LaAlO3, which suppresses H2 oxidation and strengthens CO adsorption on Au sites, thereby improving competitive oxidation of CO at elevated temperature.

  14. Biomass gasification and fuel cells: system with PEM fuel cell; Gaseificacao de biomassa e celula a combustivel: sistema com celula tipo PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Sordi, Alexandre; Lobkov, Dmitri D.; Lopes, Daniel Gabriel; Rodrigues, Jean Robert Pereira [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Fac. de Engenharia Mecanica], e-mail: asordi@fem.unicamp.br, e-mail: lobkov@fem.unicamp.br, e-mail: danielg@fem.unicamp.br, e-mail: jrobert@fem.unicamp.br; Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Inst. de Fisica Gleb Wataghin], e-mail: Lh2ennio@ifi.unicamp.br

    2006-07-01

    The objective of this paper is to present the operation flow diagram of an electricity generation system based on the biomass integrated gasification fuel cell of the type PEMFC (Proton Exchange Membrane Fuel Cell). The integration between the gasification and a fuel cell of this type consists of the gas methane (CH4) reforming contained in the synthesis gas, the conversion of the carbon monoxide (CO), and the cleaning of the gaseous flow through a PSA (Pressure Swing Adsorption) system. A preliminary analysis was carried out to estimate the efficiency of the system with and without methane gas reforming. The performance was also analyzed for different gasification gas compositions, for larger molar fractions of hydrogen and methane. The system electrical efficiency was 29% respective to the lower heating value of the gasification gas. The larger the molar fraction of hydrogen at the shift reactor exit, the better the PSA exergetic performance. Comparative analysis with small gas turbines exhibited the superiority of the PEMFC system. (author)

  15. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    Energy Technology Data Exchange (ETDEWEB)

    Hezarjaribi, M.; Jahanshahi, M., E-mail: mjahan@nit.ac.ir; Rahimpour, A.; Yaldagard, M.

    2014-03-01

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm{sup −2} was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm{sup −2}) and ESA (160 m{sup 2} gr{sup −1}) than commercial Pt/C with amount of about 10 mA cm{sup −2} and 114 m{sup 2} gr{sup −1}, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs.

  16. Construction of an electrolytic photocell fuel cell system used to energize a cellular telephone; Construccion de un sistema fotocelda-electrolizador-celda de combustible, utilizado para energizar un telefono celular

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes Quezada, Eduardo; Rodriguez-Castellanos, A.; Solorza Feria, O. [CINVESTAV-IPN, Mexico, D.F. (Mexico)]. E-mail: edfq_1986@hotmail.com

    2009-09-15

    An increase in the worldwide population (roughly 6.3 billion people) has brought about a considerable increase in the demand for energy in order to meet national energy and development needs. Oil and carbon are currently the fuels that are most widely used to generate energy. Nevertheless, their extraction and transport, in addition to their combustion, produce residual pollutants, such as carbon bioxide which is released into the atmosphere and contributes to a large amount of the planet's global warming. An alternative to electric energy generation is the use of polymeric membrane fuel cells (PEMFC), which enable the use of alternative fuels such as hydrogen. This work presents the start-up of a system consisting of a photovoltage cell, an electrolyzer and a PEMFC. The photovoltage cell transforms the solar energy into electric energy which electrolyzes the water to provide hydrogen (fuel) and oxygen (combustion). An electrolyzer was designed and built and was characterized with polarization tests. The gases obtained from the electrolyzer are fed to the fuel cell designed and built in the laboratory. To apply this work, the energy produced in the fuel cell is fed to a low-power device such as the electrical charge of a mobile phone. The integration of electrochemical devices will completely revolutionize today's energy sources, which are based on oil derivatives. These integrated systems are efficient for producing electric energy without emitting gas pollutants. [Spanish] Con el crecimiento de la poblacion mundial, (cercana a 6.3 miles de millones de habitantes en el mundo), se incrementa considerablemente la demanda de energia para cubrir las necesidades energeticas propias y del desarrollo de un pais. El petroleo y el carbon son los combustibles mas empleados en la actualidad para la generacion de energia. Sin embargo, su extraccion y transporte ademas de su combustion traen como consecuencia la produccion de residuos contaminantes, como el bioxido

  17. PEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid Vehicle

    Directory of Open Access Journals (Sweden)

    Tinton Dwi Atmaja

    2012-02-01

    Full Text Available Page HeaderOpen Journal SystemsJournal HelpUser You are logged in as...aulia My Journals My Profile Log Out Log Out as UserNotifications View (27 new ManageJournal Content SearchBrowse By Issue By Author By Title Other JournalsFont SizeMake font size smaller Make font size default Make font size largerInformation For Readers For Authors For LibrariansKeywords CBPNN Displacement FLC LQG/LTR Mixed PMA Ventilation bottom shear stress direct multiple shooting effective fuzzy logic geoelectrical method hourly irregular wave missile trajectory panoramic image predator-prey systems seawater intrusion segmentation structure development pattern terminal bunt manoeuvre Home About User Home Search Current Archives ##Editorial Board##Home > Vol 23, No 1 (2012 > AtmajaPEMFC Optimization Strategy with Auxiliary Power Source in Fuel Cell Hybrid VehicleTinton Dwi Atmaja, Amin AminAbstractone of the present-day implementation of fuel cell is acting as main power source in Fuel Cell Hybrid Vehicle (FCHV. This paper proposes some strategies to optimize the performance of Polymer Electrolyte Membrane Fuel Cell (PEMFC implanted with auxiliary power source to construct a proper FCHV hybridization. The strategies consist of the most updated optimization method determined from three point of view i.e. Energy Storage System (ESS, hybridization topology and control system analysis. The goal of these strategies is to achieve an optimum hybridization with long lifetime, low cost, high efficiency, and hydrogen consumption rate improvement. The energy storage system strategy considers battery, supercapacitor, and high-speed flywheel as the most promising alternative auxiliary power source. The hybridization topology strategy analyzes the using of multiple storage devices injected with electronic components to bear a higher fuel economy and cost saving. The control system strategy employs nonlinear control system to optimize the ripple factor of the voltage and the current

  18. Comparative analysis of 2D and 3D model of a PEMFC in COMSOL

    Science.gov (United States)

    Lakshmi, R. Bakiya; Harikrishnan, N. P.; Juliet, A. Vimala

    2017-10-01

    In this article, 2D and 3D model of a PEMFC has been simulated in order to study their performance when subjected to similar operating conditions. The comparison reveals interesting phenomena of performance enhancement of the fuel cell. Design of fuel cell channel and stationary studies were done in COMSOL. Variations in current density and electrolyte potential from simulation results were observed when operated at a temperature of 120 °C. The electrolyte potential was found to have increased from 1 to 2.5 V and the surface pressure due to fluid flow was found to have increased from 3 to 9.58 Pa.

  19. Enhanced MEA Performance for PEMFCs under Low Relative Humidity and Low Oxygen Content Conditions via Catalyst Functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Le; Yang, Fan; Xie, Jian; Yang, Zhiwei; Kariuki, Nancy N.; Myers, Deborah J.; Peng, Jui-Kun; Wang, Xiaohua; Ahluwalia, Rajesh K.; Yu, Kang; Ferreira, Paulo J.; Bonastre, Alex Martinez; Fongalland, Dash; Sharman, Jonathan

    2017-01-01

    This work demonstrates that functionalizing annealed-Pt/Ketjen black EC300j (a-Pt/KB) and dealloyed-PtNi/Ketjen black EC300j (d-PtNi/KB) catalysts using p-phenyl sulfonic acid can effectively enhance performance in the membrane electrode assemblies (MEAs) of proton exchange membrane fuel cells (PEMFCs). The functionalization increased the size of both Pt and PtNi catalyst particles and resulted in the further leaching of Ni from the PtNi catalyst while promoting the formation of nanoporous PtNi nanoparticles. The size of the SO3H-Pt/KB and SO3H-PtNi/KB carbon-based aggregates decreased dramatically, leading to the formation of catalyst layers with narrower pore size distributions.MEA tests highlighted the benefits of the surface functionalization, in which the cells with SO3H-Pt/KB and SO3H-PtNi/KB cathode catalysts showed superior high current density performance under reduced RH conditions, in comparison with cells containing annealed Pt/KB (a-Pt/KB) and de-alloyed PtNi/KB (d-PtNi/KB) catalysts. The performance improvement was particularly evident when using reactant gases with low relative humidity, indicating that the hydrophilic functional groups on the carbon improved the water retention in the cathode catalyst layer. These results show a new avenue for enhancing catalyst performance for the next generation of catalytic materials for PEMFCs.

  20. Membrane morphological study nanostructured based hydrophobic/hydrophilic applied in devices of PEMFC

    International Nuclear Information System (INIS)

    Loureiro, Felipe Augusto M.; Dahmouche, K; Rocco, Ana Maria

    2015-01-01

    The increasingly high energy demand generated by the increase of world population and consumption of fuels based on non-renewable sources has stimulated, in recent decades, the development of alternatives with less environmental impact and are based on renewable sources. Among these, the fuel cells (FC) have extremely promising possibilities. For the development of FC with market viability, it is necessary to obtain materials with optimized properties, among which the proton conducting membranes. In this work, we developed semi-interpenetrating polymer membranes (SIPN) based on diglycidyl ether of bisphenol-A (DGEBA) and polyethyleneimine (PEI), aiming their application in PEMFC. The membranes nanostructure was studied by AFM and SAXS means and it was identified ordinate hydrophobic/hydrophilic nano domains, which have determined the membrane properties, specially the proton conductivity. (author)

  1. Three-dimensional mathematical modelling of a proton-exchange membrane fuel cell (PEMFC); Dreidimensionale mathematische Modellierung einer Brennstoffzelle mit Protonen-Austausch-Membran (PEMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Mosig, J

    1997-12-01

    The use of proton-exchange membrane fuel cells (PEMFC) in motor vehicles is being explored worldwide and demonstrated in prototypes. The structural improvement of the cells requires an in-depth understanding of the physiochemical processes taking place in the interior. Mathematical simulations can considerably contribute to providing this understanding. In the present study, a mathematical model is presented which enables the calculation of mass and charge flows in the different material layers of a rectangular, planar PEM fuel cell and provides the corresponding three-dimensional concentration and potential distributions. The simulation software permits the steady-state and isothermal calculation of hydrogen/air single cells to which fuel and oxidant can be fed in a co-flow, counter-flow or cross-flow configuration. The mathematical solution method is based on the finite integration technique. The large, sparse systems of equations resulting from the discretization of the conservation equations are very efficiently solved using a multigrid method. A comparison of calculated current-density/voltage characteristics for a base-case cell with measured current-density/voltage characteristics confirms the good quality of the simulation results. Parameter variations show the dependence of the electrode kinetics on the cell temperature and on the gas pressures of the fuel and air side. Furthermore, the influence of the pressure difference between fuel and oxidant on the water regime of the electrolyte membrane is examined. Finally, simulation calculations for different fuel cell materials and ratios of gas-channel to ridge width show the influence of structural fuel cell parameters on the performance of a PEM fuel cell. (orig.) [Deutsch] Der Einsatz von Brennstoffzellen mit Protonen-Austausch-Membran (PEMFC) in Kraftfahrzeugen wird weltweit erforscht und in Prototypen demonstriert. Ihre konstruktive Verbesserung erfordert ein tiefes Verstaendnis der im Inneren ablaufenden

  2. Dynamic modelling and hardware-in-the-loop testing of PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Vath, Andreas; Soehn, Matthias; Nicoloso, Norbert; Hartkopf, Thomas [Technische Universitaet Darmstadt/Institut fuer Elektrische Energie wand lung, Landgraf-Georg-Str. 4, D-64283 Darmstadt (Germany); Lemes, Zijad; Maencher, Hubert [MAGNUM Automatisierungstechnik GmbH, Bunsenstr. 22, D-64293 Darmstadt (Germany)

    2006-07-03

    Modelling and hardware-in-the-loop (HIL) testing of fuel cell components and entire systems open new ways for the design and advance development of FCs. In this work proton exchange membrane fuel cells (PEMFC) are dynamically modelled within MATLAB-Simulink at various operation conditions in order to establish a comprehensive description of their dynamic behaviour as well as to explore the modelling facility as a diagnostic tool. Set-up of a hardware-in-the-loop (HIL) system enables real time interaction between the selected hardware and the model. The transport of hydrogen, nitrogen, oxygen, water vapour and liquid water in the gas diffusion and catalyst layers of the stack are incorporated into the model according to their physical and electrochemical characteristics. Other processes investigated include, e.g., the membrane resistance as a function of the water content during fast load changes. Cells are modelled three-dimensionally and dynamically. In case of system simulations a one-dimensional model is preferred to reduce computation time. The model has been verified by experiments with a water-cooled stack. (author)

  3. Experimental analysis of the effects of the operating variables on the performance of a single PEMFC

    International Nuclear Information System (INIS)

    Santarelli, M.G.; Torchio, M.F.

    2007-01-01

    This paper shows and discusses the results obtained after an experimental session devoted to characterization of the behavior of a single proton exchange membrane fuel cell (PEMFC) with variation of the values of six operation variables: cell temperature; anode flow temperature in saturation and dry conditions; cathode flow temperature in saturation and dry conditions; and reactants pressure. The fuel cell employed for the experiments is a single PEMFC with a 25 cm 2 Nafion[reg] 115 membrane. As expected, a higher cell temperature increases the membrane conductivity and the exchange current density with an improvement of the cell behaviour. An increase in the reactant saturation temperature also leads to a better performance, especially in the case of low and medium loads. Conversely, in the case of a low cell temperature, it is better to reduce the water inlet mass flow at high loads to avoid electrode flooding. With an increase of the reactant operating pressure, the maximum of the power curve shifts to higher current densities, and this could be linked to the corresponding shift of the limiting current density. A combined effect of humidification and operating pressure was observed: the increase of operating pressure did not offer a significant improvement when the reactants were dry, while leading to improvements when a partial humidification (only at the anode) was adopted. The best improvements due to a pressure increase were observed when both anode and cathode are humidified. Finally, some tests of other authors at the same operation conditions have been considered, and a comparison has been done

  4. Experimental investigation of open circuit voltage during start-up process of HT-PEMFC

    International Nuclear Information System (INIS)

    Abdul Rasheed, Raj Kamal; Chan, Siew Hwa

    2015-01-01

    Highlights: • OCV reduces non-linearly with temperature under constant power input. • The reduction gradient of OCV is observed to be non-linear with time. • Nernst equation is less accurate for HT-PEMFC start-up models. - Abstract: This paper investigates the open circuit voltage (OCV) during the warm-up process of a high temperature proton exchange membrane fuel cell (HT-PEMFC) from 140 °C to the desired temperature of 180 °C, where the temperature increases with time. The heating strategy involves the external heating of the fuel cell with constant heat input rate. The commonly used Nernst equation, to predict the OCV of the fuel cell, is usually used in transient start-up models. Thus, this papers highlights the limitations of using the Nernst equation where the temperature increases transiently with time. A polybenzimidazole-based HTPEM single cell was set up and the OCV was measured under constant heating power supplied by an external source. A parametric study was done by varying the external heating power and the effect on the OCV was observed. The results showed that the OCV reduces non-linearly with respect to temperature, when the fuel cell is subjected to a constant heating power. This behaviour is clearly in contrast with the Nernst equation, which considers the temperature as steady state. For effective comparison, the OCV was also measured under steady state temperatures, showing an almost constant reduction gradient of ∼ −2.3×10 −4 V/°C. However, the behaviour under a constant heating power show curvilinear reduction of the OCV as the temperature increases. In addition, as the external heating power is increased, the degree of curvature of the OCV profile is greater. Thus, the results clearly indicate that the accuracy of using the Nernst equation in transient thermal start-up models can be improved, by considering a non linear behaviour, as shown in this paper.

  5. Performance and endurance of a PEMFC operated with synthetic reformate fuel feed

    Energy Technology Data Exchange (ETDEWEB)

    Sishtla, C; Koncar, G; Platon, R [Institute of Gas Technology, Des Plaines, IL (United States); Gamburzev, S; Appleby, A J [Texas Engineering Experimental Station, Texas A and M Univ. System, College Station, TX (United States). Center for Electrochemical Systems and Hydrogen Research; Velev, O A [AeroVironment, Inc., Monrovia, CA (United States)

    1998-03-15

    Widespread implementation of polymer electrolyte membrane fuel cell (PEMFC) powerplants for stationary and vehicular applications will be dependent in the near future on using readily available hydrocarbon fuels as the source of the hydrogen fuel. Methane and propane are ideal fuels for stationary applications, while methanol, gasoline, and diesel fuel are better suited for vehicular applications. Various means of fuel processing are possible to produce a gaseous fuel containing H{sub 2}, CO{sub 2} and CO. CO is a known electrocatalyst poison and must be reduced to low (10`s) ppm levels and CO{sub 2} is said to cause additional polarization effects. Even with no CO in the feed gas a H{sub 2}/CO{sub 2}/H{sub 2}O gas mixture will form some CO. Therefore, as a first step of developing a PEMFC that can operate for thousands of hours using a reformed fuel, we used an anode gas feed of 80% H{sub 2} and 20% CO{sub 2} to simulate the reforming of CH{sub 4}. To investigate the effect of reformate on cell performance and endurance, a single cell with an active area of 58 cm{sup 2} was assembled with a membrane electrode assembly (MEA) furnished by Texas A and M University using IGT`s internally manifolded heat exchange (IMHEX{sup TM}) design configuration. The MEA consisted of a Nafion 112 membrane with anode and cathode Pt catalyst loadings of 0.26 and 1.46 mg/cm{sup 2}, respectively. The cell was set to operate on a synthetic reformate - air at 60 C and 1 atm and demonstrated over 5000 h of endurance with a decay rate of less than 1%/1000 h of operation. The cell also underwent four successful thermal cycles with no appreciable loss in performance. The stable performance is attributed to a combination of the IGT IMHEX plate design with its inherent uniform gas flow distribution across the entire active area and MEA quality. The effects of temperature, gas composition, fuel utilization (stoics) and thermal cycle on cell performance are described. (orig.)

  6. Durability Improvement of Pt/RGO Catalysts for PEMFC by Low-Temperature Self-Catalyzed Reduction.

    Science.gov (United States)

    Sun, Kang Gyu; Chung, Jin Suk; Hur, Seung Hyun

    2015-12-01

    Pt/C catalyst used for polymer electrolyte membrane fuel cells (PEMFCs) displays excellent initial performance, but it does not last long because of the lack of durability. In this study, a Pt/reduced graphene oxide (RGO) catalyst was synthesized by the polyol method using ethylene glycol (EG) as the reducing agent, and then low-temperature hydrogen bubbling (LTHB) treatment was introduced to enhance the durability of the Pt/RGO catalyst. The cyclic voltammetry (CV), oxygen reduction reaction (ORR) analysis, and transmittance electron microscopy (TEM) results suggested that the loss of the oxygen functional groups, because of the hydrogen spillover and self-catalyzed dehydration reaction during LTHB, reduced the carbon corrosion and Pt agglomeration and thus enhanced the durability of the electrocatalyst.

  7. An investigation on the electrocatalytic properties of polypyrrole films on the kinetics of oxygen reduction reaction in PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Saremi, M.; Sharifi Asl, S.; Kazemi, Sh. [Tehran Univ., Tehran (Iran, Islamic Republic of). School of Metallurgy and Material Science Engineering

    2008-07-01

    A proton exchange membrane (PEM) fuel cell has high power density, low weight, very short start-up time and no leakage of electrolytes. However, there are some disadvantages when operating the PEM fuel cell at room temperature. Many studies involving the widespread commercial use of Pt-based electrocatalysts search for low-cost electrocatalysts for the oxygen reduction reaction. In recent years, much attention has been placed on the use of electrocatalysis for the conducting polymer electrode. Polypyrrole has attracted much attention as an advanced conducting material because of its good environmental stability, easy synthesis and high conductivity. This study examined the effect of the polypyrrole catalyst in a PEMFC cathode. The electropolymerization of pyrrole was carried out in a 3-electrode cell using pure hydrogen and oxygen as the reactants. Tests were carried out at room temperature and cell impedance was measured. The polymer was formed galvanostatically in a 0.1 M pyrrole with a 0.15 KCl aqueous solution with a 20 mA/cm{sup 2} current density. The effect of operating voltage and oxygen mass transport was examined by EIS method, which separates these two phenomena. The study showed that polypyrrole has a catalytic effect for oxygen reduction reaction in PEMFC comparable to a Pt catalyzed electrode. Although the cell potential with polypyrrole was slightly lower than a Pt coated cell, it was found to be more economical. 8 refs., 2 figs.

  8. Technological Monitoring Applied to Survey-Based on Brazilian Patent Applications about PEMFC

    Directory of Open Access Journals (Sweden)

    Deysimar de Souza Carvalho

    2011-06-01

    Full Text Available The present study aims to show the importance of patents as an instrument of technological innovation and to assess the relevance of technology of PEMFC in Brazil by means of the technological monitoring methodology from 1996 to 2005. This study used different Industrial Property Databases (INPI-BR, ESPACENET and DWPI, in order to retrieve the BR applications in each database. Relevant keywords as “fuel cell” were used in combination with specific IPC (H01M8 in order to assess the main applicants, countries, IPCs and technological innovation over time. In Brazil, the country holding more requests in this area is the United States (US with 53,7% of the patent applications, while Brazil (BR accounts for 4,4% of the total requests. It was also observed that the North-American company, UTC Fuel Cells comes on top of the list and that there were no patent applications of Brazilian origin (BR in other countries.

  9. Design of a tubular ceramic membrane for gas separation in a PEMFC system

    Energy Technology Data Exchange (ETDEWEB)

    Kamarudin, S.K.; Daud, W.R.W.; Mohammad, A.W.; Som, A.Md.; Takriff, M.S. [Department of Chemical and Process Engineering, National University of Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2004-01-01

    The objective of this study is to introduce a shortcut in the method of design for a tubular ceramic membrane (TCM) for gas separation. Generally, it explains the permeation of the multi component gas using cross flow models in a porous membrane and the surface area of the membrane required. The novel aspect of this method is that the expression for the length of the membrane is simplified to a number unit (NTU) and a height of transfer unit (HTU). The HTU term for porous membranes is characterised by the physical properties of the membrane; the feed flow rate, n{sub F}, membrane thickness, l{sub M}, feed pressure, P{sub F}, K the permeability of gas and the diameter of the membrane, D{sub M}. The integral for NTU of a porous membrane is the solution for the local permeate along the length of the membrane. It is found that, NTU mainly depends on the rejection stream, x{sub R,}, along the membrane and it describes the relative degree of separation. The Proton Electrolyte Membrane Fuel Cell (PEMFC) system is taken as the case study. CO is the main culprit in reducing the performance of the PEMFC and will act as a catalyst poison for the fuel cell anode at a concentration as low as 100 ppm. Thus, the reformate, from primary reforming, contains a significant amount of CO and must be purified. The effect of some important parameters such as temperature, pressure and the thickness of membrane to the degree of separation are presented in this paper. From the results, it can be seen that the system could reduce the CO concentration from 2000 - 500 ppm. Basically the TCM will operate, in series, with a pressure swing adsorber in order to further reduce the concentration of CO to less than 10 ppm before entering the fuel cell stack. However, this paper only focuses on the design of the TCM. Besides this, it is observed that the purity of the hydrogen increased from 72.8 - 96% (at {theta} = 0.5) after the membrane. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  10. In-situ measurement of electroosmotic drag coefficient in Nafion membrane for the PEMFC.

    Science.gov (United States)

    Peng, Zhe; Morin, Arnaud; Huguet, Patrice; Schott, Pascal; Pauchet, Joël

    2011-11-10

    A new method based on hydrogen pump has been developed to measure the electroosmotic drag coefficient in representative PEMFC operating conditions. It allows eliminating the back-flow of water which leads to some errors in the calculation of this coefficient with previously reported electrochemical methods. Measurements have been performed on 50 μm thick Nafion membranes both extruded and recast. Contrary to what has been described in most of previous published works, the electroosmotic drag coefficient decreases as the membrane water content increases. The same trend is observed for temperatures between 25 and 80 °C. For the same membrane water content, the electroosmotic drag coefficient increases with temperature. In the same condition, there is no difference in drag coefficient for extruded Nafion N112 and recast Nafion NRE212. These results are discussed on the basis of the two commonly accepted proton transport mechanisms, namely, Grotthus and vehicular.

  11. Development of a Stochastically-driven, Forward Predictive Performance Model for PEMFCs

    Science.gov (United States)

    Harvey, David Benjamin Paul

    A one-dimensional multi-scale coupled, transient, and mechanistic performance model for a PEMFC membrane electrode assembly has been developed. The model explicitly includes each of the 5 layers within a membrane electrode assembly and solves for the transport of charge, heat, mass, species, dissolved water, and liquid water. Key features of the model include the use of a multi-step implementation of the HOR reaction on the anode, agglomerate catalyst sub-models for both the anode and cathode catalyst layers, a unique approach that links the composition of the catalyst layer to key properties within the agglomerate model and the implementation of a stochastic input-based approach for component material properties. The model employs a new methodology for validation using statistically varying input parameters and statistically-based experimental performance data; this model represents the first stochastic input driven unit cell performance model. The stochastic input driven performance model was used to identify optimal ionomer content within the cathode catalyst layer, demonstrate the role of material variation in potential low performing MEA materials, provide explanation for the performance of low-Pt loaded MEAs, and investigate the validity of transient-sweep experimental diagnostic methods.

  12. Review on the Recent Developments of Photovoltaic Thermal (PV/T and Proton Exchange Membrane Fuel Cell (PEMFC Based Hybrid System

    Directory of Open Access Journals (Sweden)

    Zulkepli Afzam

    2016-01-01

    Full Text Available Photovoltaic Thermal (PV/T system emerged as one of the convenient type of renewable energy system acquire the ability to generate power and thermal energy in the absence of moving parts. However, the power output of PV/T is intermittent due to dependency on solar irradiation condition. Furthermore, its efficiency decreases because of cells instability at high temperature. On the other hand, fuel cell co-generation system (CGS is another technology that can generate power and heat simultaneously. Integration of PV/T and fuel cell CGS could enhance the reliability and sustainability of both systems as well as increasing the overall system performance. Hence, this paper intended to present the parameters that affect performance of PV/T and Proton Exchange Membrane Fuel Cell (PEMFC CGS. Moreover, recent developments on PV/T-fuel cell hybrid system are also presented. Based on literates, mass flow rate of moving fluid in PV/T was found to affect the system efficiency. For the PEMFC, when the heat is utilized, the system performance can be increased where the heat efficiency is similar to electrical efficiency which is about 50%. Recent developments of hybrid PV/T and fuel cell show that most of the studies only focus on the power generation of the system. There are less study on the both power and heat utilization which is indeed necessary in future development in term of operation strategy, optimization of size, and operation algorithm.

  13. Asymmetric bi-layer PFSA membranes as model systems for the study of water management in the PEMFC.

    Science.gov (United States)

    Peng, Z; Peng, A Z; Morin, A; Huguet, P; Lanteri, Y; Deabate, S

    2014-10-14

    New bi-layer PFSA membranes made of Nafion® NRE212 and Aquivion™ E79-05s with different equivalent weights are prepared with the aim of managing water repartition in the PEMFC. The membrane water transport properties, i.e. back-diffusion and electroosmosis, as well as the electrochemical performances, are compared to those of state-of-art materials. The actual water content (the inner water concentration profile across the membrane thickness) is measured under operation in the fuel cell by in situ Raman microspectroscopy. The orientation of the equivalent weight gradient with respect to the water external gradient and to the proton flow direction affects the membrane water content, the water transport ability and, thus, the fuel cell performances. Higher power outputs, related to lower ohmic losses, are observed when the membrane is assembled with the lower equivalent weight layer (Aquivion™) at the anode side. This orientation, corresponding to enhanced water transport by back-flow while electroosmosis remains unaffected, results in the higher hydration of the membrane and of the anode active layer during operation. Also, polarization data suggest a different water repartition in the fuel cell along the on-plane direction. Even if the interest in multi-layer PFSA membranes as perspective electrolytes for PEMFCs is not definitively attested, these materials appear to be excellent model systems to establish relationships between the membrane transport properties, the water distribution in the fuel cell and the electrochemical performances. Thanks to the micrometric resolution, in situ Raman microspectroscopy proves to be a unique tool to measure the actual hydration of the membrane at the surface swept by the hydrated feed gases during operation, so that it can be used as a local probe of the water concentration evolution along the gas distribution channels according to changing working conditions.

  14. “Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

    Energy Technology Data Exchange (ETDEWEB)

    Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Tolj, I.; Davids, M.W.; Bujlo, P. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Smith, F. [Impala Platinum Ltd, Springs (South Africa); Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2015-10-05

    Highlights: • Prototype hydrogen storage and supply system for LTPEMFC applications was developed. • Combination of MH and CGH2 tanks with common gas manifold was used. • Thermal coupling of fuel cell stack and MH tank was applied. • The system uses AB2-type MH; H2 equilibrium pressure ∼10 bar at room temperature. • Shorter H2 charge time and stable H2 supply at a fluctuating load were observed. - Abstract: This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB{sub 2}-type MH material (H{sub 2} equilibrium pressure of about 10 bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H{sub 2} charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H{sub 2} consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system.

  15. “Distributed hybrid” MH–CGH2 system for hydrogen storage and its supply to LT PEMFC power modules

    International Nuclear Information System (INIS)

    Lototskyy, M.; Tolj, I.; Davids, M.W.; Bujlo, P.; Smith, F.; Pollet, B.G.

    2015-01-01

    Highlights: • Prototype hydrogen storage and supply system for LTPEMFC applications was developed. • Combination of MH and CGH2 tanks with common gas manifold was used. • Thermal coupling of fuel cell stack and MH tank was applied. • The system uses AB2-type MH; H2 equilibrium pressure ∼10 bar at room temperature. • Shorter H2 charge time and stable H2 supply at a fluctuating load were observed. - Abstract: This paper describes the layout and presents the results of the testing of a novel prototype “distributed hybrid” hydrogen storage and supply system that has the potential to be used for Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC) applications. The system consists of individual Metal Hydride (MH) and Compressed Gas (CGH2) tanks with common gas manifold, and a thermal management system where heat exchanger of the liquid heated-cooled MH tank is integrated with the cooling system of the LT-PEMFC BoP. The MH tank is filled with a medium-stability AB 2 -type MH material (H 2 equilibrium pressure of about 10 bar at room temperature). This innovative solution allows for (i) an increase in hydrogen storage capacity of the whole gas storage system and the reduction of H 2 charge pressure; (ii) shorter charging times in the refuelling mode and smoother peaks of H 2 consumption during its supply to the fuel cell stack; (iii) the use of standard parts with simple layout and lower costs; and (iv) adding flexibility in the layout and placement of the components of the hydrogen storage and supply system

  16. Elaboration, physical and electrochemical characterizations of CO tolerant PEMFC anode materials. Study of platinum-molybdenum and platinum-tungsten alloys and composites; Elaborations et caracterisations electrochimiques et physiques de materiaux d'anode de PEMFC peu sensibles a l'empoisonnement par CO: etude d'alliages et de composites a base de platine-molybdene et de platine-tungstene

    Energy Technology Data Exchange (ETDEWEB)

    Peyrelade, E.

    2005-06-15

    PEMFC development is hindered by the CO poisoning ability of the anode platinum catalyst. It has been previously shown that the oxidation potential of carbon monoxide adsorbed on the platinum atoms can be lowered using specific Pt based catalysts, either metallic alloys or composites. The objective is then to realize a catalyst for which the CO oxidation is compatible with the working potential of a PEMFC anode. In our approach, to enhance the CO tolerance of platinum based catalyst supported on carbon, we studied platinum-tungsten and platinum-molybdenum alloys and platinum-metal oxide materials (Pt-WO{sub x} and Pt-MoO{sub x}). The platinum based alloys demonstrate a small effect of the second metal towards the oxidation of carbon monoxide. The platinum composites show a better tolerance to carbon monoxide. Electrochemical studies on both Pt-MoO{sub x} and Pt-WO{sub x} demonstrate the ability of the metal-oxides to promote the ability of Pt to oxidize CO at low potentials. However, chrono-amperometric tests reveal a bigger influence of the tungsten oxide. Complex chemistry reactions on the molybdenum oxide surface make it more difficult to observe. (author)

  17. Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC por impressão a tela

    Directory of Open Access Journals (Sweden)

    Rafael Nogueira Bonifácio

    2011-01-01

    Full Text Available Proton exchange membrane fuel cell (PEMFC requires membrane electrode assemblies (MEA to generate electrical energy from hydrogen and oxygen. In this study a MEA production process by sieve printing and an ink composition were developed to produce catalyst layers of MEAs. The deposition of the exact catalyst content was possible on cathodes and anodes with only one print step. The optimal ink developed shown viscosity of 2.75 Pa s, density 1.27 g cm-3, total solid content of 33.76 % and tack of 92 U.T. The electrodes prepared in only one printing step showed higher performance than those prepared in several steps.

  18. Bifunctional electrodes with ir and Ru oxide mixtures and pt for unified regenerative cells; Electrodos bifuncionales basados en mezclas de oxidos de Ir y Ru con Pt para celdas regenerativas unificadas

    Energy Technology Data Exchange (ETDEWEB)

    Duron-Torres, S.M.; Escalante-Garcia, I.L. [Universidad Autonoma de Zacatecas, Zacatecas (Mexico); Cruz, J. C.; Arriaga-Hurtado; L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Pedro Escobedo, Queretaro (Mexico)]. E-mail: duronsm@prodigy.net.mx

    2009-09-15

    Unified regenerative fuel cells (URFC) represent an attractive option to obtain hydrogen and generate energy using a compact device. Nevertheless, the fusion of a fuel cell (PEMFC) and a water electrolyzer continue to be a challenge because of the wide range of conditions to which this type of device is subject. Because of its kinetic characteristics, oxygen reduction reaction (ORR) in PEMFC and oxygen evolution reaction (OER) in PEMWE are the limiting stages of the URFC depending on the mode of operation. The primary focus of research related to URFC is the obtainment of bifunctional electrocatalysts that satisfactorily perform in both oxygen reactions and support the different working conditions found in a fuel cell and an electrolyzer. The present work contributes to the research on bifunctional electrocatalysts and shows some preliminary results from the electrochemical study of different Pt gcc, IrO{sub 2} and RuO{sub 2} mixtures supported in Ebonex® as oxygen electrodes. The electrochemical characterization with cyclic voltamperometry (CV), linear voltamperometry (LV) and electrochemical impedance spectroscopy (EIS) in H{sub 2}SO{sub 4} 0.5 M, in the absence and present of oxygen shows that Ebonex®-supported bifunctional electrodes IrO{sub 2}-Pt and RuO{sub 2}-Pt present reasonable electrocatalytic properties for oxygen evolution and reduction reactions and present the possibility of their use in an URFC. The Ir- based oxide electrodes show greater stability than ruthenium-oxide electrodes. [Spanish] Las celdas de combustible regenerativas unificadas (URFC) representan una atractiva opcion para la obtencion de hidrogeno y generacion de energia en un dispositivo compacto. Sin embargo, la fusion de una celda de combustible (PEMFC) y un electrolizador de agua (PEMWE) sigue siendo un reto por la amplia gama de condiciones a que se sujeta un dispositivo de este tipo. Por sus caracteristicas cineticas, la reaccion de reduccion de oxigeno (ORR) en la PEMFC y la

  19. Influence of cold work on electrochemical behavior of 316L ASS in PEMFC environment

    Science.gov (United States)

    Tandon, Vipin; Patil, Awanikumar P.; Rathod, Ramesh C.; Shukla, Sourabh

    2018-02-01

    The influence of cold work (CW) on electrochemical behavior of 316L ASS in PEMFC (0.5M H2SO4 + 2 ppm HF at 70 °C) environment was investigated by microstructural observations, x-ray diffraction (XRD), polarization, electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) techniques. The XRD is used to analyze the increase in dislocation density and formation of α‧-martensite with increasing CW degree. The EIS is used to find out the effect of substrate dislocation density on the film resistance. The EIS result show that with increasing CW, the diameter of depressed semi-circular arc and consequently film resistance decreased. This indicates the formation of highly disordered and porous film on CW. From PDP results, it is found that icrit, ip and icorr increased on increasing CW degree. Moreover, the direct relationship was drawn from the dislocation density of the substrate to the defect density of the passive film from M-S technique.

  20. Testing and model-aided analysis of a 2 kW el PEMFC CHP-system

    Science.gov (United States)

    König, P.; Weber, A.; Lewald, N.; Aicher, T.; Jörissen, L.; Ivers-Tiffée, E.; Szolak, R.; Brendel, M.; Kaczerowski, J.

    A prototype PEMFC CHP-system (combined heat and power) for decentralised energy supply in domestic applications has been installed in the Fuel Cell Testing Laboratory at the Institut für Werkstoffe der Elektrotechnik (IWE), Universität Karlsruhe (TH). The system, which was developed at the Zentrum für Sonnenenergie- und Wasserstoff-Forschung ZSW, Ulm (FC-stack) and the Fraunhofer-Institut für Solare Energiesysteme ISE, Freiburg (reformer) is operated and tested in close cooperation with the Stadtwerke Karlsruhe. The tests are carried out as part of the strategic project EDISon, which is supported by the German Federal Ministry of Economics and Technology (BMWA). The performance of the system is evaluated for different operating conditions. The tests include steady state measurements under different electrical and thermal loads as well as an analysis of the dynamic behaviour of the system during load changes. First results of these steady state and dynamic operation characteristics will be presented in this paper.

  1. Characterization of self-assembled electrodes based on Au-Pt nanoparticles for PEMFC application

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, E. [Univ. Politecnica de Chiapas (Mexico). Energia y Sustentabilidad; Sebastian, P.J.; Gamboa, S.A.; Joseph, S. [Univ. Nacional Autonoma de Mexico, Morelos (Mexico). Centrode Investigacion en Energia; Pal, U. [Univ. Autonoma de Puebla, Pue (Mexico). Inst. de Fisica; Gonzalez, I. [Univ. Autonoma Metropolitana, Mexico City (Mexico). Dept. de Quimica

    2010-07-01

    This paper described the synthesis and characterization of gold (Au), platinum (Pt) and Au-Pt nanoparticles impregnated on a Nafion membrane in a proton exchange membrane fuel cell (PEMFC). The aim of the study was to fabricate the membrane electrode assembly (MEA) by depositing the nanoparticles on the membrane using an immersion technique. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to study the deposition process. Electrochemical impedance spectroscopy (EIS) was used to study the membrane proton conduction process. An elemental mapping analysis was performed in order to study the location of the Au and Pt in the self-assemblies. Results of the study showed that the particles deposited on the Nafion had good stability and a homogenous distribution along the membrane surface. The particles showed a direct relation in size and location with the hydrophilic and hydrophobic distribution phases of the membrane. The main membrane resistance was located between the membrane and the electrolyte. The self-assembled electrodes demonstrated a good performance at standard conditions. 33 refs., 4 tabs., 11 figs.

  2. Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

    Directory of Open Access Journals (Sweden)

    Mallika Gummalla

    2015-05-01

    Full Text Available The initial performance and decay trends of polymer electrolyte membrane fuel cells (PEMFC cathodes with Pt3Co catalysts of three mean particle sizes (4.9 nm, 8.1 nm, and 14.8 nm with identical Pt loadings are compared. Even though the cathode based on 4.9 nm catalyst exhibited the highest initial electrochemical surface area (ECA and mass activity, the cathode based on 8.1 nm catalyst showed better initial performance at high currents. Owing to the low mass activity of the large particles, the initial performance of the 14.8 nm Pt3Co-based electrode was the lowest. The performance decay rate of the electrodes with the smallest Pt3Co particle size was the highest and that of the largest Pt3Co particle size was lowest. Interestingly, with increasing number of decay cycles (0.6 to 1.0 V, 50 mV/s, the relative improvement in performance of the cathode based on 8.1 nm Pt3Co over the 4.9 nm Pt3Co increased, owing to better stability of the 8.1 nm catalyst. The electron microprobe analysis (EMPA of the decayed membrane-electrode assembly (MEA showed that the amount of Co in the membrane was lower for the larger particles, and the platinum loss into the membrane also decreased with increasing particle size. This suggests that the higher initial performance at high currents with 8.1 nm Pt3Co could be due to lower contamination of the ionomer in the electrode. Furthermore, lower loss of Co from the catalyst with increased particle size could be one of the factors contributing to the stability of ECA and mass activity of electrodes with larger cathode catalyst particles. To delineate the impact of particle size and alloy effects, these results are compared with prior work from our research group on size effects of pure platinum catalysts. The impact of PEMFC operating conditions, including upper potential, relative humidity, and temperature on the alloy catalyst decay trends, along with the EMPA analysis of the decayed MEAs, are reported.

  3. Life cycle assessment (LCA) methodology: importance in the integration of the fuel cell technology type PEMFC (proton exchange membrane fuel cells); Metodologia da analise de ciclo de vida: importancia na insercao da tecnologia de celula a combustivel do tipo PEMFC (membrana polimerica trocadora de protons)

    Energy Technology Data Exchange (ETDEWEB)

    Fukurozaki, Sandra Harumi; Seo, Emilia Satoshi Miyamaru [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)). Centro de Ciencia e Tecnologia de Materiais], e-mail: shfukuro@ipen.br

    2004-07-01

    To improve the standard of society's quality of life, it is necessary to improve the quality of distributed energy and its inherent services within a sustainability process. Among different technological routes that produce more sustainable energy are the fuel cells - also known as combustible batteries. The Global Environment Facility (GEF) has identified the fuel cells as a potential technology to reduce, in the future, the effect of greenhouse gases in both developed and developing countries. Although there are various types of fuel cells, the most used technology for research studies on fuel cells is the Polymer Electrolyte Fuel Cells (FEMFC). However, economic issues - related to the high cost of the membrane's materials and of the catalysts of groups of platinum metals - are still some of the obstacles that need to be overcome for this technology to be more accessible. There are also socio-environmental aspects related to the impacts caused by the extraction, the use and the destination of these metals. Taking in consideration the challenges of complying with the demands of the market and the society as well as with the growing tendency of more rigid patterns of environmental control, the objective of the present work is to show the tool of environmental management - Life Cycle Assessment (LCA) - and its importance on the pursuit for socio-economic and environmental alternatives feasible to the recycling of the catalysts of platinum of the PEMFC. This way, it intends to collaborate to the progress of the knowledge about environmental and socio-economic subjects related to the productive process of the PEMFC. (author)

  4. Transient analysis of carbon monoxide transport phenomena and adsorption kinetics in HT-PEMFC during dynamic current extraction

    International Nuclear Information System (INIS)

    Raj, Kamal Abdul Rasheedj; Chan, Siew Hwa

    2015-01-01

    Highlights: • Increasing the fuel cell temperature reduces outlet CO concentration. • Increasing the CO inlet (initial) concentration increases outlet CO concentration. • Increasing current density step and dwell time increases outlet CO concentration. • Increasing in the CL and GDL porosities reduces outlet CO concentration. - Abstract: This paper investigates the transport phenomena of carbon monoxide (CO) and adsorption kinetics, in a high-temperature proton exchange membrane fuel cell (HT-PEMFC) during step-wise current extraction (step-change in current extraction). Step-wise current extraction is a common process done to accommodate a sudden power surge during an operation. Since HT-PEMFCs are capable of handling high impurity of CO, hydrogen fuel that is contaminated with trace amount of CO is usually considered for commercial benefits. Thus, a transient three-dimensional isothermal anodic electro-kinetic numerical model is developed to determine the effect of operating parameters such as fuel cell temperature, CO inlet (initial) concentration, step-change of current density and dwell time on the transport phenomena of CO and adsorption kinetics. In addition, geometrical factors such as the catalyst layer (CL) and gas diffusion layer (GDL) porosity are also varied as well. The results show that the above-mentioned operating parameters can affect the maximum CO concentration at the CL, especially at the outlet of the channel. Specifically, a reduction of fuel cell temperature can significantly increase the CO concentration near the outlet, while increasing CO inlet (initial) concentration, step-change amplitude of current density and current density dwell time can cause an increase in CO concentration at the outlet, albeit to different extent. In addition, the increase in the porosity of CL and GDL, results in the reduction of the maximum CO concentration at the outlet, albeit to different extent. In addition, the CO and hydrogen surface coverage

  5. Optimal stochastic scheduling of CHP-PEMFC, WT, PV units and hydrogen storage in reconfigurable micro grids considering reliability enhancement

    International Nuclear Information System (INIS)

    Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

    2017-01-01

    Highlights: • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Uncertainties of wind speed, solar radiation and electricity market price are considered. • Profit maximization, emission and AENS minimization are considered as objective functions. • Modified firefly algorithm is employed to solve the problem. - Abstract: Nowadays the operation of renewable energy sources and combined heat and power (CHP) units is increased in micro grids; therefore, to reach optimal performance, optimal scheduling of these units is required. In this regard, in this paper a micro grid consisting of proton exchange membrane fuel cell-combined heat and power (PEMFC-CHP), wind turbines (WT) and photovoltaic (PV) units, is modeled to determine the optimal scheduling state of these units by considering uncertain behavior of renewable energy resources. For this purpose, a scenario-based method is used for modeling the uncertainties of electrical market price, the wind speed, and solar irradiance. It should be noted that the hydrogen storage strategy is also applied in this study for PEMFC-CHP units. Market profit, total emission production, and average energy not supplied (AENS) are the objective functions considered in this paper simultaneously. Consideration of the above-mentioned objective functions converts the proposed problem to a mixed integer nonlinear programming. To solve this problem, a multi-objective firefly algorithm is used. The uncertainties of parameters convert the mixed integer nonlinear programming problem to a stochastic mixed integer nonlinear programming problem. Moreover, optimal coordinated scheduling of renewable energy resources and thermal units in micro-grids improve the value of the objective functions. Simulation results obtained from a modified 33-bus distributed network as a micro grid illustrates the effectiveness of the proposed method.

  6. Employment of fluorine doped zinc tin oxide (ZnSnOx:F) coating layer on stainless steel 316 for a bipolar plate for PEMFC

    International Nuclear Information System (INIS)

    Park, Ji Hun; Byun, Dongjin; Lee, Joong Kee

    2011-01-01

    Highlights: → Preparation of fluorine doped tin oxide (SnOx:F) and fluorine doped zinc tin oxide (ZnSnOx:F) coating layer on the surface of stainless steel 316 bipolar plate for PEMFCs (Proton Exchange Membrane Fuel Cells). → Evaluations of the corrosion resistance and the interfacial contact resistance of the bare, SnOx:F and ZnSnOx:F thin film coated stainless steel 316 bipolar plates. → Evaluation of single cell performance such as cell voltage and power density using bare stainless steel, SnOx:F and ZnSnOx:F film coated bipolar plates. - Abstract: The investigation of the electrochemical characteristics of the fluorine doped tin oxide (SnOx:F) and fluorine doped zinc tin oxide (ZnSnOx:F) was carried out in the simulated PEMFC environment and bare stainless steel 316 was used as a reference. The results showed that the ZnSnOx:F coating enhanced both the corrosion resistance and interfacial contact resistance (ICR). The corrosion current for ZnSnOx:F was 1.2 μA cm -2 which was much lower than that of bare stainless steel of 50.16 μA cm -2 . The ZnSnOx:F coated film had the smallest corrosion current due to the formation of a tight surface morphology with very few pin-holes. The ZnSnOx:F coated film exhibited the highest values of the cell voltage and power density due to its having the lowest ICR values.

  7. Pt based PEMFC catalysts prepared from colloidal particle suspensions--a toolbox for model studies.

    Science.gov (United States)

    Speder, Jozsef; Altmann, Lena; Roefzaad, Melanie; Bäumer, Marcus; Kirkensgaard, Jacob J K; Mortensen, Kell; Arenz, Matthias

    2013-03-14

    A colloidal synthesis approach is presented that allows systematic studies of the properties of supported proton exchange membrane fuel cell (PEMFC) catalysts. The applied synthesis route is based on the preparation of monodisperse nanoparticles in the absence of strong binding organic stabilizing agents. No temperature post-treatment of the catalyst is required rendering the synthesis route ideally suitable for comparative studies. We report work concerning a series of catalysts based on the same colloidal Pt nanoparticle (NP) suspension, but with different high surface area (HSA) carbon supports. It is shown that for the prepared catalysts the carbon support has no catalytic co-function, but carbon pre-treatment leads to enhanced sticking of the Pt NPs on the support. An unwanted side effect, however, is NP agglomeration during synthesis. By contrast, enhanced NP sticking without agglomeration can be accomplished by the addition of an ionomer to the NP suspension. The catalytic activity of the prepared catalysts for the oxygen reduction reaction is comparable to industrial catalysts and no influence of the particle size is found in the range of 2-5 nm.

  8. Controlling system for an experimental demonstration plant for energy conversion using PEMFCs

    International Nuclear Information System (INIS)

    Culcer, Mihail; Iliescu, Mariana; Stefanescu, Ioan; Raceanu, Mircea; Enache, Adrian; Patularu, Laurentiu

    2006-01-01

    Full text: In the last decades of the previous century, due to global environmental problems, energy security and supply issues, many studies were conducted to investigate the uses for hydrogen energy and facilitate its penetration as an energy carrier. Subsequently, many industries worldwide began developing and producing hydrogen, hydrogen-powered vehicles, hydrogen fuel cells, and other hydrogen-based technologies. In view of the substantial long-term public and private benefits arising from hydrogen and fuel cells, the European Union and national governments throughout Europe, including the Romanian one, are working towards developing a consistent policy framework preparing the transition to a hydrogen based economy. ICIT Rm Valcea developed a research program on energy conversion using fuel cells, a project supported by the Romanian Ministry of Education and Research within the National R and D Program. An experimental demonstration pilot plant of energy conversion using PEMFCs and hydrogen producing via steam methane reforming (SMR) was achieved in order to investigate the development of small-scale SMR technologies and to allow testing and developing of specific components. The paper deals with the dedicated controlling system that provides automated data acquisition, manual or 'on line' operational control, gas management, humidification, temperature and flow controls of the pilot plant. (authors)

  9. Catalyst layers for PEMFC manufactured by flexography printing process: performances and structure

    Energy Technology Data Exchange (ETDEWEB)

    Bois, C.; Blayo, A.; Chaussy, D. [Laboratory of Pulp and Paper Science and Graphic Arts (LGP2) (UMR 5518 CNRS-CTP-INPG), Grenoble Institute of Technology (INP Grenoble - PAGORA), St Martin d' Heres (France); Vincent, R.; Mercier, A.G.; Nayoze, C. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA)/DRT/LITEN, Laboratoire des Composants Piles a Combustible, Electrolyse et Modelisation (LCPEM), Grenoble (France)

    2012-04-15

    This article focuses on the potential of a classic printing process, flexography, for manufacturing proton exchange membrane fuel cells (PEMFCs). Gas diffusion electrodes (GDEs) are produced by deposition of a water-based catalyst ink on a gas diffusion layer (GDL). The affinity between the ink and the GDL is quantified. Thus, the strong hydrophobic character of the GDL and the poor printability of the ink are demonstrated. However, the permeability of the GDL allows developing a multilayer protocol. The deposition by superimposition of ink layers allows control of the platinum amount and to obtain catalyst layers with a similar density of platinum nanoparticles to coated samples. At similar platinum loading, flexography and coating made catalyst layers offer similar performances, which confirm the relevance of flexography in catalyst layer manufacturing. Structural characterization shows that manufacturing protocol and process has an influence on catalyst layer microstructure. However, catalyst layer cracking and aggregation are increased with the catalyst layer thickness, diminishing the charge and gas diffusion into the catalyst layer resulting in performance degradation. Consequently, a catalyst layer with 0.46 mgPt cm{sup -2} reaches similar performances to catalyst layers with 1.77 and 2.01 times less platinum loading. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Study and development of membrane electrode assemblies for Proton Exchange Membrane Fuel Cell (PEMFC) with palladium based catalysts

    International Nuclear Information System (INIS)

    Bonifacio, Rafael Nogueira

    2013-01-01

    PEMFC systems are capable of generating electricity with high efficiency and low or no emissions, but durability and cost issues prevent its large commercialization. In this work MEA with palladium based catalysts were developed, Pd/C, Pt/C and alloys PdPt/C catalysts with different ratios between metals and carbon were synthesized and characterized. A study of the ratio between catalyst and Nafion Ionomer for formation of high performance triple-phase reaction was carried out, a mathematical model to implement this adjustment to catalysts with different relations between metal and support taking into account the volumetric aspects of the catalyst layer was developed and then a study of the catalyst layer thickness was performed. X-ray diffraction, Transmission and Scanning Electron Microscopy, X-ray Energy Dispersive, Gas Pycnometry, Mercury Intrusion Porosimetry, Gas adsorption according to the BET and BJH equations, and Thermo Gravimetric Analysis techniques were used for characterization and particle size, specific surface areas and lattice parameters determinations were also carried out. All catalysts were used on MEAs preparation and evaluated in 5 cm 2 single cell from 25 to 100 °C at 1 atm and the best composition was also evaluated at 3 atm. In the study of metals for reactions, to reduce the platinum applied to the electrodes without performance losses, Pd/C and PdPt/C 1:1 were selected for anodes and cathodes, respectively. The developed MEA structure used 0,25 mgPt.cm -2 , showing power densities up to 550 mW.cm -2 and power of 2.2 kW net per gram of platinum. The estimated costs showed that there was a reduction of up to 64.5 %, compared to the MEA structures previously known. Depending on the temperature and operating pressure, values from US$ 1,475.30 to prepare MEAs for each installed kilowatt were obtained. Taking into account recent studies, it was concluded that the cost of the developed MEA is compatible with PEMFC stationary application

  11. Stacks with TiN/titanium as the bipolar plate for PEMFCs

    International Nuclear Information System (INIS)

    Ren, Zhijun; Zhang, Dongming; Wang, Zaiyi

    2012-01-01

    Proton exchange membrane fuel cell (PEMFC) is a potential alternative for the internal combustion engine. But many problems, such as metallic bipolar plate instead of graphite bipolar plate to decrease the cost, should be solved before its application. Based on the previous results that single cell with TiN/Ti as bipolar plates shows high performance and enough long-time durability, the progress on the stacks with TiN/Ti as bipolar plates is reported in this manuscript. Till now seldom report is focused on stacks because of the complicated processing technique, especially for that with TiN/Ti as bipolar plate. The flow field in the plate is punched from titanium deformation, and two plates are welded by laser welding to form one piece of bipolar plate. The adopted processing techniques for stacks with TiN/Ti as bipolar plate exhibit advantage and feasibility in industry. The power density by weight for the stack is as high as 1353 W kg −1 , although it still has space to be improved. Next work should be focused on the design of flow channel parameters and flow field type based on plastic deformation of metal materials. -- Highlights: ► The progress on the stacks with TiN/Ti as bipolar plates is reported. ► The adopted processing techniques exhibit feasibility in industry. ► The power density by weight for the stack is as high as 1353 W kg −1 .

  12. Synthesis of protons exchange polymeric membranes via co-poly-esters doped with sodium dodecyl sulfate for application in PEM fuel cells; Sintese de membranas polimericas condutoras de protons por imobilizacao de MDs em copoliesteres para aplicacao em PEM-FC

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.A.; Brioude, M.M.; Bresciani, D.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica

    2008-07-01

    Polymers are largely studied for use in PEM-type fuel cell (Proton Exchange membrane, PEMFC). These fuel cells are based on polymer membranes as electrolyte, also called protons conductor. This work developed co-polyesters made electrical conductors by doping with sodium dodecyl sulfate. The copolymers were synthesized from the copolymerization of terephthalic and adipic acids with glycerol. The material was processed in a reactor and shaped by hot pressing, yielding homogeneous and flexible plates, with excellent surface finish. The co-polyesters were analyzed by SEM, FTIR, TG, DSC, and XRD. The thermal analysis showed that the composites were thermally stable up to about 250 deg C. The micrographics revealed the MDS homogeneously dispersed in the polymeric matrix. These copolymers showed electrical conductivity between 10-7 to 10-1 S/cm, suggesting strong potential use in PEM fuel cells. (author)

  13. Fuel cell systems and traditional technologies. Part II: Experimental study on dynamic behavior of PEMFC in stationary power generation

    International Nuclear Information System (INIS)

    Venturelli, Lucia; Santangelo, Paolo E.; Tartarini, Paolo

    2009-01-01

    The present work is focused on electric generation for stationary applications. The dynamic behavior of a PEMFC-based system has been investigated at both constant and variable load conditions from an experimental point of view. An analysis of efficiency as a function of time has been proposed to summarize the dynamic performance; moreover, current intensity and voltage have been considered as main parameters of interest from the electric point of view. In addition, other energetic and thermodynamic parameters have been studied in this work. The experimental campaign has been carried out over four test typologies: constant load; increasing and decreasing load; random load. These tests have been planned to challenge the system with a variety of load-based cycles, in the frame of a thorough simulation of real-load conditions.

  14. Using adaptive neuro fuzzy inference system (ANFIS) for proton exchange membrane fuel cell (PEMFC) performance modeling

    International Nuclear Information System (INIS)

    Rezazadeh, S.; Mirzaee, I.; Mehrabi, M.

    2012-01-01

    In this paper, an adaptive neuro fuzzy inference system (ANFIS) is used for modeling proton exchange membrane fuel cell (PEMFC) performance using some numerically investigated and compared with those to experimental results for training and test data. In this way, current density I (A/cm 2 ) is modeled to the variation of pressure at the cathode side P C (atm), voltage V (V), membrane thickness (mm), Anode transfer coefficient α an , relative humidity of inlet fuel RH a and relative humidity of inlet air RH c which are defined as input (design) variables. Then, we divided these data into train and test sections to do modeling. We instructed ANFIS network by 80% of numerical validated data. 20% of primary data which had been considered for testing the appropriateness of the models was entered ANFIS network models and results were compared by three statistical criterions. Considering the results, it is obvious that our proposed modeling by ANFIS is efficient and valid and it can be expanded for more general states

  15. Using adaptive neuro fuzzy inference system (ANFIS) for proton exchange membrane fuel cell (PEMFC) performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Rezazadeh, S.; Mirzaee, I. [Urmia Univ., Urmia (Iran, Islamic Republic of); Mehrabi, M. [University of Pretoria, Pretoria (South Africa)

    2012-11-15

    In this paper, an adaptive neuro fuzzy inference system (ANFIS) is used for modeling proton exchange membrane fuel cell (PEMFC) performance using some numerically investigated and compared with those to experimental results for training and test data. In this way, current density I (A/cm{sup 2}) is modeled to the variation of pressure at the cathode side P{sup C} (atm), voltage V (V), membrane thickness (mm), Anode transfer coefficient {alpha}{sup an}, relative humidity of inlet fuel RH{sup a} and relative humidity of inlet air RH{sup c} which are defined as input (design) variables. Then, we divided these data into train and test sections to do modeling. We instructed ANFIS network by 80% of numerical validated data. 20% of primary data which had been considered for testing the appropriateness of the models was entered ANFIS network models and results were compared by three statistical criterions. Considering the results, it is obvious that our proposed modeling by ANFIS is efficient and valid and it can be expanded for more general states.

  16. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates; Opmisation des proprietes de conduction electrique et de passivite d'aciers inoxydables pour la realisation de plaques bipolaires de pile a combustible de type PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Andre, J

    2007-10-15

    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  17. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates; Opmisation des proprietes de conduction electrique et de passivite d'aciers inoxydables pour la realisation de plaques bipolaires de pile a combustible de type PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Andre, J

    2007-10-15

    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  18. Development of a membrane electrode assembly process for proton exchange membrane fuel cell (PEMFC)

    International Nuclear Information System (INIS)

    Baldo, Wilians Roberto

    2003-01-01

    In this work, a Membrane Electrode Assembly (MEA) producing process was developed, involving simple steps, aiming cost reduction and good reproducibility for Proton Exchange Membrane Fuel Cell (PEMFC) commercial applications. The electrodes were produced by spraying ink into both sides of the polymeric membrane, building the catalytic layers, followed by hot pressing of Gas Diffusion Layers (GDL), forming the MEA. This new producing method was called 'Spray and hot pressing hybrid method'. Concerning that all the parameters of spray and hot pressing methods are interdependent, a statistical procedure were used in order to study the mutual variables influences and to optimize the method. This study was earned out in two distinct steps: the first one, where seven variables were considered for the analysis and the second one, where only the variables that interfered in the process performance in the first step were considered for analysis. The results showed that the developed process was adequate, including only simple steps, reaching MEA's performance of 651 m A cm -2 at a potential of 600 mV for catalysts loading of 0,4 mg cm -2 Pt at the anode and 0,6 mg cm -2 Pt at the cathode. This result is compared to available commercial MEA's, with the same fuel cell operations conditions. (author)

  19. Entropy generation analysis of a proton exchange membrane fuel cell (PEMFC) with a fermat spiral as a flow distributor

    International Nuclear Information System (INIS)

    Rangel-Hernandez, V.H.; Damian-Ascencio, C.; Juarez-Robles, D.; Gallegos-Munoz, A.; Zaleta-Aguilar, A.; Plascencia-Mora, H.

    2011-01-01

    The present paper aims at investigating the main sources of irreversibility in a Proton Exchange Membrane Fuel Cell (PEMFC) using a Fermat spiral as flow distributor and also to direct possible improvements in its design. The numerical analysis is based on a finite volume technique with a SIMPLE algorithm as numerical procedure. In order to have a more complete and rigorous analysis a new dimensionless parameter is proposed here. The parameter represents the ratio of the entropy generation due to mass transfer to the total entropy generation is proposed here. Results demonstrate that the main sources of irreversibility in a fuel cell are the concentration losses for the most part of the operational domain, whereas the heat transfer effect is not dominant. -- Highlights: → PEM Fuel Cell with Fermat Spiral as distributor. → Causes of irreversibilities. → A new dimensionless parameter to determine contribution of mass transfer in entropy generation.

  20. A strain-controlled C2N monolayer membrane for gas separation in PEMFC application

    Science.gov (United States)

    Deng, Shengwei; Hu, Hui; Zhuang, Guilin; Zhong, Xing; Wang, Jianguo

    2018-05-01

    Ultrathin membranes with controllable pore sizes have great potential to realize high-selectivity gas separation at low energy cost, especially for those mixtures with narrow size distributions. Using a combination of van der Waals-corrected density functional theory (DFT) calculations and molecular dynamics (MD) simulation, we examine the separation ability of biaxial stretched monolayer C2N nanosheets which is applied to the O2 separation from CO/CO2/O2 mixtures in the cathode of proton exchange membrane fuel cells (PEMFC). The DFT calculations show that the diffusion energy barrier for molecules passing through the membrane followed by CO, CO2 and O2 in descending order, and an overall decrease of energy barriers due to the widen the pore size is observed with the increase of applied strains. Furthermore, MD results show that the nanosheet can effectively purify O2 from CO2 and CO with a strain from 8% to 10%. It confirms that the selectivity is determined by the electronic structure related interaction in addition to the kinetic diameter of individual molecules. The O2 permeability is improved progressively with further increase of strain, and small amount of CO2 begins to permeate through the nanosheet at relatively large strain, while the excellent CO isolation is not compromised until the theoretical maximum strain.

  1. Modification of the liquid cooling channel of PEMFCs for their operation with dry reactant gases

    International Nuclear Information System (INIS)

    Shyu, Jin-Cherng; Hsueh, Kan-Lin; Tsau, Fanghei; Chen, Fa-Lin

    2011-01-01

    In order to tackle both water and thermal problems, a modified PEMFC is proposed in the present study for its operation with dry reactant gases via the modification of liquid cooling channel with circulating liquid electrolyte. Fuel cell with both circulating liquid electrolyte and solid polymer membrane operated with either dry or humidified H 2 /O 2 is compared in the present study at temperatures of 40, 50, 65, and 80 o C, respectively. The measured E-I data show that such single cell can be operated at 80 o C without humidification. Besides, a semi-empirical equation to predict the current/voltage relationship, and the electrochemical impedance method are also employed in the present study for cell resistance analysis. The analysis results show that the high interfacial resistance should be one of the major reasons for the inferior performance of the present cell. Based on the discovery, an improvement of the present fuel cell is further proposed by Nafion ionomer spreading on the electrode before the assembly of membrane and electrode. The maximum power density of the cell after electrode treatment reaches 75 mW/cm 2 for dry H 2 /O 2 operation at 0.4 V, which is almost threefold improvement compared with that without electrode treatment.

  2. Evaluation and characterization of ceramic membranes based on Pdms/SiC containing phosphotungstic acid as electrolytes for PEM-FC

    International Nuclear Information System (INIS)

    Lima, Marcelo de Oliveira; Guimaraes, Danilo Hansen; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede; Barbosa, Diego Augusto Batista; Paschoal, Carlos William de Araujo; Almeida, Rafael Mendonca; Tanaka, Auro Atsushi

    2009-01-01

    This work presents the development of membranes with potential use in Proton Exchange Fuel Cells (PEM-FC), consisting of hybrid materials based on poly(dimethylsiloxane), crosslinked with tetraethyl orthosilicate (TEOS), and reinforced with silicon carbide and phosphotungstic acid. The membrane series PDMS/TEOS/SiC/PWA were prepared by the reaction of PDMS and TEOS, 70/30% proportions in mass, catalyzed by dibutyltin dilaurate. SiC was incorporated in a 25% proportion, and PWA in varied proportions (5, 10, 15 and 20%), by weight. The membranes were characterized by Thermo-Gravimetric Analysis (TGA), X-ray Diffraction, Scanning Electron Microscopy and impedance spectroscopy. SiC and PWA addition to the membrane increased both structure organization and material crystallinity. The insertion of PWA provided an increase in the conductivity. However, maximum conductivity was obtained with concentration levels above 10%. The insertion of SiC associated with the PWA did not influence the conductivity for concentrations between 10 and 20%. (author)

  3. Spraying Techniques for Large Scale Manufacturing of PEM-FC Electrodes

    Science.gov (United States)

    Hoffman, Casey J.

    Fuel cells are highly efficient energy conversion devices that represent one part of the solution to the world's current energy crisis in the midst of global climate change. When supplied with the necessary reactant gasses, fuel cells produce only electricity, heat, and water. The fuel used, namely hydrogen, is available from many sources including natural gas and the electrolysis of water. If the electricity for electrolysis is generated by renewable energy (e.g., solar and wind power), fuel cells represent a completely 'green' method of producing electricity. The thought of being able to produce electricity to power homes, vehicles, and other portable or stationary equipment with essentially zero environmentally harmful emissions has been driving academic and industrial fuel cell research and development with the goal of successfully commercializing this technology. Unfortunately, fuel cells cannot achieve any appreciable market penetration at their current costs. The author's hypothesis is that: the development of automated, non-contact deposition methods for electrode manufacturing will improve performance and process flexibility, thereby helping to accelerate the commercialization of PEMFC technology. The overarching motivation for this research was to lower the cost of manufacturing fuel cell electrodes and bring the technology one step closer to commercial viability. The author has proven this hypothesis through a detailed study of two non-contact spraying methods. These scalable deposition systems were incorporated into an automated electrode manufacturing system that was designed and built by the author for this research. The electrode manufacturing techniques developed by the author have been shown to produce electrodes that outperform a common lab-scale contact method that was studied as a baseline, as well as several commercially available electrodes. In addition, these scalable, large scale electrode manufacturing processes developed by the author are

  4. Employment and income generation within the framework of the 'Luz para todos' program in the State of Amazonas, Brazil; Geracao de emprego e renda no ambito do programa Luz para Todos no estado do Amazonas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Rubem Cesar Rodrigues; Moraes, Betsy Eddy Praia; Souza, Cristiane Daliassi Ramos de [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Centro de Desenvolvimento Energetico Amazonico

    2008-07-01

    The low level of the electric demand to be accomplished in the isolated Amazon communities, associated to the low purchasing power of those populations and the high costs for electrification of these, they impose the implementation of concrete actions of generation of job and income when it intend to assure the universalization of the electric power service in isolated Amazon communities, as ir the case of the program 'Luz para Todos'. The present article shows that is being developed by the committee state manager of the program 'Luz para Todos' in the amazon state, demonstrating that it is possible to assure good results since the effective involvement of several agents is made possible. (author)

  5. Negligible degradation upon in situ voltage cycling of a PEMFC using an electrospun niobium-doped tin oxide supported Pt cathode.

    Science.gov (United States)

    Savych, Iuliia; Subianto, Surya; Nabil, Yannick; Cavaliere, Sara; Jones, Deborah; Rozière, Jacques

    2015-07-14

    Novel platinum-catalysed, corrosion-resistant, loose-tube-structured electrocatalysts for proton exchange membrane fuel cells have been obtained using single-needle electrospinning associated with a microwave-assisted polyol method. Monodisperse platinum particles supported on Nb-SnO2 demonstrated higher electrochemical stability than conventional Pt/C electrodes during ex situ potential cycling and comparable activity in the oxygen reduction reaction. In situ fuel cell operation under accelerated stress test conditions of a membrane electrode assembly elaborated using a Pt/C anode and Pt/Nb-SnO2 cathode confirmed that the voltage loss is significantly lower for the novel cathode than for an MEA prepared using conventional Pt/C supported electrocatalysts. Furthermore, the Nb-SnO2 stabilised the supported platinum nanoparticles against dissolution, migration and reprecipitation in the membrane. Pt/Nb-SnO2 loose-tubes constitute a mitigation strategy for two known degradation mechanisms in PEMFC: corrosion of the carbon support at the cathode, and dissolution of Pt at high cell voltages.

  6. Evaluation of Electrochemical Characteristics on Graphene Coated Austenitic and Martensitic Stainless Steels for Metallic Bipolar Plates in PEMFC Fabricated with Hydrazine Reduction Methods

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Seong-Yun; Lee, Jae-Bong [School of Advanced Materials Engineering, Kookmin University, Seoul (Korea, Republic of)

    2016-04-15

    Graphene was coated on austenitic and martensitic stainless steels to simulate the metallic bipolar plate of proton exchange membrane fuel cell (PEMFC). Graphene oxide (GO) was synthesized and was reduced to reduced graphene oxide (rGO) via a hydrazine process. rGO was confirmed by FE-SEM, Raman spectroscopy and XPS. Interfacial contact resistance (ICR) between the bipolar plate and the gas diffusion layer (GDL) was measured to confirm the electrical conductivity. Both ICR and corrosion current density decreased on graphene coated stainless steels. Corrosion resistance was also improved with immersion time in cathodic environments and satisfied the criteria of the Department of Energy (DOE), USA. The total concentrations of metal ions dissolved from graphene coated stainless steels were reduced. Furthermore hydrophobicity was improved by increasing the contact angle.

  7. Comparison of The Performance of Proton Exchange Membrane Fuel Cell (PEMFC Electrodes with Different Carbon Powder Content and Methods of Manufacture

    Directory of Open Access Journals (Sweden)

    Dedi Rohendi

    2016-11-01

    Full Text Available Carbon powder in the gas diffusion layer (GDL contained in the membrane electrode assembly (MEA has an important role in the flow of electrons and reactant gas. Meanwhile, the method of making the electrode is one of the many studies conducted to determine the most appropriate method to use. Comparative study of the performance of proton exchange membrane fuel cell (PEMFC electrodes with different carbon powder content (vulcan XC-72 in the GDL and methods of manufacture of the electrode between casting and spraying method has been carried out. The spraying method consists of one layer and three layer of catalyst layer (CL. The content of carbon powder in the GDL as much as 3 mg cm-2 has a better performance compared to 1.5 mg cm-2 with an increase of 177.78% current density at 0.6 V. Meanwhile, the manufacture of CL with three-layer spraying method has better performance compared with one-layer spraying and casting method.

  8. PEMFC performance of MEAS based on Nafion{sup R} and sPSEBS hybrid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Carretero, F.J.; Compan, V. [Univ, Politecnica de Valencia, Valencia (Spain). Dept. Termodinamica Aplicada; Suarez, K.; Solorza, O. [Inst. Politecnico Nacional, Centro de Investigacion y de Estudios Avanzados, Mexico City (Mexico). Dept. de Quimica; Riande, E. [Inst. de Ciencia y Tecnologia de Polimeros, Madrid (Spain)

    2010-07-15

    Important scientific, technical and economic problems must be solved before widespread commercialization of polymer electrolyte membrane fuel cells (PEMFC). The main issues facing the development of commercial low temperature fuel cells are the synthesis of efficient solid electrolytes separating the anode from the cathode as well as the development of cheaper catalysts for fuel oxidation. This study involved the preparation of hybrid membranes based on Nafion 117 and sulfonated Calprene H6120 containing partially sulfonated inorganic fillers such as silica, SBA-15 and sepiolite. The feasibility of using the membranes as polyelectrolytes for low temperature fuel cells was then evaluated. The water uptake of Nafion hybrid membranes is 1/3 to 1/4 of that in composite membranes based on sulfonated Calprene H6120. The proton conductivity of Nafion 117 hybrid membranes-electrode assemblies is nearly 1/5 of the pristine Nafion membrane assembly. Sulfonated Calprene H6120 hybrid membranes typically have better proton conductivity than the Nafion 117 composites. The performance of fuel cells containing different MEAs was examined by measuring their polarization curves in different operating conditions. The kinetic parameters governing the voltage dependence on current density were also estimated. It was concluded that the superior performance of the fuel cells with MEAs of NAF-SEP, sPSEBS-SIL and sPSEBS-SBA is not due to the membranes themselves, but to the kinetic processes that occur at the electrodes, which in this study were less efficient for fuel cells with the Nafion MEA. 34 refs., 3 tabs., 9 figs.

  9. Comparison of high-temperature and low-temperature polymer electrolyte membrane fuel cell systems with glycerol reforming process for stationary applications

    International Nuclear Information System (INIS)

    Authayanun, Suthida; Mamlouk, Mohamed; Scott, Keith; Arpornwichanop, Amornchai

    2013-01-01

    Highlights: • PEMFC systems with a glycerol steam reformer for stationary application are studied. • Performance of HT-PEMFC and LT-PEMFC systems is compared. • HT-PEMFC system shows good performance over LT-PEMFC system at a high current density. • HT-PEMFC system with water gas shift reactor shows the highest system efficiency. • Heat integration can improve the efficiency of HT-PEMFC system. - Abstract: A high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has a major advantage over a low-temperature polymer electrolyte fuel cell (LT-PEMFC) demonstrated by a tolerance to a higher CO content in the hydrogen feed and thus a simpler fuel processing. In this study, a direct comparison between the performance of HT-PEMFC and LT-PEMFC systems integrated with a glycerol steam reformer with and without a water gas shift reactor is shown. Under pure hydrogen operation, the LT-PEMFC performance is superior to the HT-PEMFC. However, the HT-PEMFC system shows good performance over the LT-PEMFC system when operated under high current density and high pressure (3 atm) and using the reformate gas derived from the glycerol processor as fuel. At high current density, the high concentration of CO is the major limitation for the operation of HT-PEMFC system without water gas shift reactor, whereas the LT-PEMFC suffers from CO poisoning and restricted oxygen mass transport. Considering the system efficiency with co-heat and power generation, the HT-PEMFC system with water gas shift reactor shows the highest overall system efficiency (approximately 60%) and therefore one of the most suitable technologies for stationary applications

  10. The PEM fuel cell as a residential power source; Die PEMFC in der Hausenergieversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Gummert, G [HGC Hamburg Gas Consult GmbH, Hamburg (Germany)

    1999-12-31

    The firm HGC, Hamburg Gas Consult GmbH, has been offering CHP systems based on fuel cells since 1996. There still is only one series product on the market, the 200 kW{sub el} or 220 kW{sub th} PC 25 system produced by ONSI, South Windsor, USA. Seven phosphoric acid fuel cell-driven CHPs with a total capacity of 1.4 MW{sub el} have been designed, installed and put into operation by the HGC engineers. Whereas the PC 25 system of ONSI is optimal for applications such as integration into a local heating network, fabrication of small-size phosphoric acid fuel cell systems with a capacity of just 50 kW{sub el} has been found to be non-profitable. For applications requiring 50 kW{sub el} or less, another fuel cell type is much more promising: the polymer electrolyte membrane fuel cell (PEMFC). (orig./CB) [Deutsch] Seit 1996 bietet die HGC Hamburg Gas Consult GmbH Kraft-Waermekopplung mit Brennstoffzellen an. Das einzige Serienprodukt ist damals wie heute die bei der Fa. ONSI in South Windsor, USA, gebaute PC 25 mit 200 kW{sub el} und 220 kW{sub th}. Sieben phosphorsaure Brennstoffzellen-BHKW mit einer Gesamtleistung von 1,4 MW{sub el} wurden bereits von den HGC-Ingenieuren geplant, installiert und in Betrieb genommen. Waehrend die ONSI PC 25 ideal als Blockheizkraftwerk an einem Nahwaermenetz eingesetzt werden kann, rentiert sich die Herstellung kleinerer phosphorsaurer Brennstoffzellenaggregate z.B. mit 50 kW{sub el} Leistung nicht. Fuer Anwendungen im Bereich <50 kW{sub el} bietet sich deshalb ein anderer Brennstoffzellentyp an: Die Polymer Electrolyt Membran Brennstoffzelle (PFMFC). (orig.)

  11. On-line and real-time diagnosis method for proton membrane fuel cell (PEMFC) stack by the superposition principle

    Science.gov (United States)

    Lee, Young-Hyun; Kim, Jonghyeon; Yoo, Seungyeol

    2016-09-01

    The critical cell voltage drop in a stack can be followed by stack defect. A method of detecting defective cell is the cell voltage monitoring. The other methods are based on the nonlinear frequency response. In this paper, the superposition principle for the diagnosis of PEMFC stack is introduced. If critical cell voltage drops exist, the stack behaves as a nonlinear system. This nonlinearity can explicitly appear in the ohmic overpotential region of a voltage-current curve. To detect the critical cell voltage drop, a stack is excited by two input direct test-currents which have smaller amplitude than an operating stack current and have an equal distance value from the operating current. If the difference between one voltage excited by a test current and the voltage excited by a load current is not equal to the difference between the other voltage response and the voltage excited by the load current, the stack system acts as a nonlinear system. This means that there is a critical cell voltage drop. The deviation from the value zero of the difference reflects the grade of the system nonlinearity. A simulation model for the stack diagnosis is developed based on the SPP, and experimentally validated.

  12. Development of an Internal Real-Time Wireless Diagnostic Tool for a Proton Exchange Membrane Fuel Cell.

    Science.gov (United States)

    Lee, Chi-Yuan; Chen, Chia-Hung; Tsai, Chao-Hsuan; Wang, Yu-Syuan

    2018-01-13

    To prolong the operating time of unmanned aerial vehicles which use proton exchange membrane fuel cells (PEMFC), the performance of PEMFC is the key. However, a long-term operation can make the Pt particles of the catalyst layer and the pollutants in the feedstock gas bond together (e.g., CO), so that the catalyst loses reaction activity. The performance decay and aging of PEMFC will be influenced by operating conditions, temperature, flow and CO concentration. Therefore, this study proposes the development of an internal real-time wireless diagnostic tool for PEMFC, and uses micro-electro-mechanical systems (MEMS) technology to develop a wireless and thin (PEMFC; (5) customized design and development. The flexible integrated microsensor is embedded in the PEMFC, three important physical quantities in the PEMFC, which are the temperature, flow and CO, can be measured simultaneously and instantly, so as to obtain the authentic and complete reaction in the PEMFC to enhance the performance of PEMFC and to prolong the service life.

  13. Channel geometric scales effect on performance and optimization for serpentine proton exchange membrane fuel cell (PEMFC)

    Science.gov (United States)

    Youcef, Kerkoub; Ahmed, Benzaoui; Ziari, Yasmina; Fadila, Haddad

    2017-02-01

    A three dimensional computational fluid dynamics model is proposed in this paper to investigate the effect of flow field design and dimensions of bipolar plates on performance of serpentine proton exchange membrane fuel cell (PEMFC). A complete fuel cell of 25 cm2 with 25 channels have been used. The aim of the work is to investigate the effect of flow channels and ribs scales on overall performance of PEM fuel cell. Therefore, geometric aspect ratio parameter defined as (width of flow channel/width of rib) is used. Influences of the ribs and openings current collector scales have been studied and analyzed in order to find the optimum ratio between them to enhance the production of courant density of PEM fuel cell. Six kind of serpentine designs have been used in this paper included different aspect ratio varying from 0.25 to 2.33 while the active surface area and number of channels are keeping constant. Aspect ratio 0.25 corresponding of (0.4 mm channel width/ 1.6mm ribs width), and Aspect ratio2.33 corresponding of (0.6 mm channel width/ 1.4mm ribs width. The results show that the best flow field designs (giving the maximum density of current) are which there dimensions of channels width is minimal and ribs width is maximal (Γ≈0.25). Also decreasing width of channels enhance the pressure drop inside the PEM fuel cell, this causes an increase of gazes velocity and enhance convection process, therefore more power generation.

  14. Perspectives for the coal thermoelectric generation; Perspectivas para a geracao termeletrica a carvao

    Energy Technology Data Exchange (ETDEWEB)

    Marreco, Juliana de M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Planejamento Energetico; Pereira Junior, Amaro; Tavares, Marina E. [EPE - Empresa de Pesquisa Energetica, Rio de Janeiro, RJ (Brazil)

    2006-07-01

    This paper presents coal future perspectives on power generation. Based on a global market point of view and on demand scenarios. Positive and negative aspects are analysed: if on one hand it may be the solution for safety energy supply, by the other hand it may jeopardize the environment. Nevertheless, new clean coal technologies are now available overcoming some of these difficulties. Without any bias, the paper objective is to provide data for a fair valuation over the coal expansion on power generation in the world and in Brazil. (author)

  15. An artificial neural network ensemble method for fault diagnosis of proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    Shao, Meng; Zhu, Xin-Jian; Cao, Hong-Fei; Shen, Hai-Feng

    2014-01-01

    The commercial viability of PEMFC (proton exchange membrane fuel cell) systems depends on using effective fault diagnosis technologies in PEMFC systems. However, many researchers have experimentally studied PEMFC (proton exchange membrane fuel cell) systems without considering certain fault conditions. In this paper, an ANN (artificial neural network) ensemble method is presented that improves the stability and reliability of the PEMFC systems. In the first part, a transient model giving it flexibility in application to some exceptional conditions is built. The PEMFC dynamic model is built and simulated using MATLAB. In the second, using this model and experiments, the mechanisms of four different faults in PEMFC systems are analyzed in detail. Third, the ANN ensemble for the fault diagnosis is built and modeled. This model is trained and tested by the data. The test result shows that, compared with the previous method for fault diagnosis of PEMFC systems, the proposed fault diagnosis method has higher diagnostic rate and generalization ability. Moreover, the partial structure of this method can be altered easily, along with the change of the PEMFC systems. In general, this method for diagnosis of PEMFC has value for certain applications. - Highlights: • We analyze the principles and mechanisms of the four faults in PEMFC (proton exchange membrane fuel cell) system. • We design and model an ANN (artificial neural network) ensemble method for the fault diagnosis of PEMFC system. • This method has high diagnostic rate and strong generalization ability

  16. Quasi-three dimensional dynamic modeling of a proton exchange membrane fuel cell with consideration of two-phase water transport through a gas diffusion layer

    International Nuclear Information System (INIS)

    Kang, Sanggyu

    2015-01-01

    Water management is one of the challenging issues for low-temperature PEMFCs (proton exchange membrane fuel cells). When liquid water is formed at the GDL (gas diffusion layer), the pathway of reactant gas can be blocked, which inhibits the electrochemical reaction of PEMFC. Thus, liquid water transport through GDL is a critical factor determining the performance of a PEMFC. In present study, quasi-three dimensional dynamic modeling of PEMFC with consideration of two-phase water transport through GDL is developed. To investigate the distributions of PEMFC characteristics, including current density, species mole fraction, and membrane hydration, the PEMFC was discretized into twenty control volumes along the anode channel. To resolve the mass and energy conservation, the PEMFC is discretized into eleven and fifteen control volumes in the perpendicular direction, respectively. The dynamic variation of PEMFC characteristics of cell voltage, overvoltage of activation and ohmic, liquid water saturation through a GDL, and oxygen concentration were captured during transient behavior. - Highlights: • A quasi-three dimensional two-phase dynamic model of PEMFC is developed. • Presented model is validated by comparison with experimental data. • Two-phase model is compared with one-phase model at steady-states and transients.

  17. Recubrimientos meso-porosos de SiO2-TiO2-P2O5 para aplicaciones en pilas de combustible de intercambio protónico

    Directory of Open Access Journals (Sweden)

    Castro, Y.

    2014-08-01

    Full Text Available The article describes the preparation of mesoporous SiO2-TiO2-P2O5 coatings by Sol-Gel process combined to EISA method for using as proton exchange membranes fuel cells. Tetraethylorthosilicate (TEOS, methyl triethoxysilane (MTES, titanium tetrachloride (TiCl4 and phosphorus trichloride (PCl3 have used as precursors and cetyl trimethylammonium bromide (CTAB as porous generator agent. Films were deposited by immersion technique controlling the relative humidity at 40 and 20-70% and treated at 400 to 500° C for 15, 30, 45 and 60 min. The variation of the refractive index and thickness have studied as a function of temperature and sintering time as well as the pore volume and density of the coatings by spectroscopic ellipsometry. Moreover, the hydrophobic/hydrophilic character of the coatings has been studied by Transform Infrared Spectroscopy (FTIR and by contact angle measurements, following the loss of methyl groups with the temperature and sintering time. The results show that these parameters are crucial to obtain coatings with high porosity and low contact angle, important to obtain high proton conductivity conditions. The sintering conditions were fixed to 400°C / 60 min. Conductivity measurements at four points show high proton conductivity, 0,16 and 0,85 S/cm, up and down ramp, respectively, at 80°C and 80 % of humidity. These coatings are good candidates for PEMFC membranes, if they are deposited onto electrodes.El artículo describe la preparación de recubrimientos mesoporosos de SiO2-TiO2-P2O5 por el método sol-gel combinado con el método EISA para su aplicación como membranas en pilas de intercambio protónico. Se han utilizado como precursores el tetraetilortosilicato (TEOS, metil-trietoxi-silano (MTES, tetracloruro de titanio (TiCl4 y el tricloruro de fosforo (PCl3 y como agente generador de porosidad el bromuro de cetil trimetilamonio (CTAB. Los recubrimientos se depositaron mediante la técnica de inmersión controlando la

  18. Proton exchange nanohybrid membranes with high phosphotungstic acid loading within metal-organic frameworks for PEMFC applications

    International Nuclear Information System (INIS)

    Zhang, Bei; Cao, Ying; Li, Zhen; Wu, Hong; Yin, Yongheng; Cao, Li; He, Xueyi; Jiang, Zhongyi

    2017-01-01

    A novel approach to in-situ synthesize and encapsulate phosphotungstic acid into the cavity of MIL-101(Cr) using Na 2 WO 4 ·2H 2 O and Na 2 HPO 4 as precursors is presented to increase the acid loading content (31.4 wt.%). The phosphotungstic acid-encapsulating MIL-101(Cr) (HPW@MIL101) is introduced in sulfonated poly(ether ether ketone) (SPEEK) to prepare SPEEK/HPW@MIL101 nanohybrid membranes for PEMFC applications. Due to the introduction of HPW@MIL101, proton-conducting nanochannels are constructed both in the cavity of MIL101 and at the interface between HPW@MIL101 and SPEEK. Meanwhile, due to the hygroscopicity of phosphotungstic acid, the membrane dehydration at elevated temperatures is alleviated. The proton conductivity at low relative humidity is remarkably enhanced. The nanohybrid membrane with 9 wt.% HPW@MIL101 exhibits proton conductivity of 272 mS cm −1 at 65 °C, 100% RH and 6.51 mS cm −1 at 60 °C, 40% RH, which are 45.5% and 7.25 times higher than those of pristine SPEEK membrane (187 mS cm −1 and 0.898 mS cm −1 ), respectively. The single H 2 /O 2 fuel cell with SPEEK/HPW@MIL-9 membrane acquires the power density of 383 mW cm −2 at 100% RH, which is 27.2% higher than that of pristine SPEEK membrane. The peak power density of SPEEK/HPW@MIL-9 membrane at 55% RH is 2.97 times higher than that of pristine SPEEK membrane (79 mW/cm 2 ).

  19. Para-Hermitian and para-quaternionic manifolds

    International Nuclear Information System (INIS)

    Ivanov, S.; Zamkovoy, S.

    2003-10-01

    A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S 1 x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)

  20. Para-Hermitian and para-quaternionic manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria) and Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Zamkovoy, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria)

    2003-10-01

    A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S{sup 1} x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)

  1. A preliminary study of a miniature planar 6-cell PEMFC stack combined with a small hydrogen storage canister

    Science.gov (United States)

    Zhang, Xigui; Zheng, Dan; Wang, Tao; Chen, Cong; Cao, Jianyu; Yan, Jian; Wang, Wenming; Liu, Juanying; Liu, Haohan; Tian, Juan; Li, Xinxin; Yang, Hui; Xia, Baojia

    The fabrication and performance evaluation of a miniature 6-cell PEMFC stack based on Micro-Electronic-Mechanical-System (MEMS) technology is presented in this paper. The stack with a planar configuration consists of 6-cells in serial interconnection by spot welding one cell anode with another cell cathode. Each cell was made by sandwiching a membrane-electrode-assembly (MEA) between two flow field plates fabricated by a classical MEMS wet etching method using silicon wafer as the original material. The plates were made electrically conductive by sputtering a Ti/Pt/Au composite metal layer on their surfaces. The 6-cells lie in the same plane with a fuel buffer/distributor as their support, which was fabricated by the MEMS silicon-glass bonding technology. A small hydrogen storage canister was used as fuel source. Operating on dry H 2 at a 40 ml min -1 flow rate and air-breathing conditions at room temperature and atmospheric pressure, the linear polarization experiment gave a measured peak power of 0.9 W at 250 mA cm -2 for the stack and average power density of 104 mW cm -2 for each cell. The results suggested that the stack has reasonable performance benefiting from an even fuel supply. But its performance tended to deteriorate with power increase, which became obvious at 600 mW. This suggests that the stack may need some power assistance, from say supercapacitors to maintain its stability when operated at higher power.

  2. Dynamic simulation of a fuel cell hybrid vehicle during the federal test procedure-75 driving cycle

    International Nuclear Information System (INIS)

    Kang, Sanggyu; Min, Kyoungdoug

    2016-01-01

    Highlights: • Development of a FCHV dynamic model. • Integration of a PEMFC system dynamic model with the electric vehicle model. • Investigation of the dynamic behavior of the FCEV and PEMFC system during FTP-75. • Capturing the dynamic correlation among components in PEMFC system during FTP-75. - Abstract: The dynamic behavior of a proton exchange membrane fuel cell (PEMFC) system is a crucial factor to ensure the safe and effective operation of fuel cell hybrid vehicles (FCHVs). Specifically, water and thermal management are critical to stabilize the performance of the PEMFC during severe load changes. In the present study, the FCHV dynamic model is developed. The dynamic model of the PEMFC system developed by Matlab–Simulink® is integrated into the electric vehicle model embedded in the Amesim®. The dynamic model of the PEMFC system is composed of a PEMFC stack, an air feeding system, and a thermal management system (TMS). The component models of PEMFC, a shell-and-tube gas-to-gas membrane humidifier, and a heat exchanger are validated via a comparison with the experimental data. The FCHV model is simulated during a federal test procedure (FTP)-75 driving cycle. One system configuration and control strategy is adopted to attain optimal water and thermal management in the PEMFC system. The vehicle speed obtained from the FCHV model aptly tracks the target velocity profile of the FTP-75 cycle within an error of ±0.5%. The dynamic behavior and correlation of each component in the PEMFC system is investigated. The mass and heat transfer in the PEMFC, a humidifier, and a heat exchanger are resolved to determine the species concentration and the temperature more accurately with discretization in the flow’s perpendicular direction. Discretization in the flow parallel direction of humidifier and heat exchanger model makes it possible to capture the distribution of the characteristics. The present model can be used to attain the optimization of the system

  3. Development of an Internal Real-Time Wireless Diagnostic Tool for a Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2018-01-01

    Full Text Available To prolong the operating time of unmanned aerial vehicles which use proton exchange membrane fuel cells (PEMFC, the performance of PEMFC is the key. However, a long-term operation can make the Pt particles of the catalyst layer and the pollutants in the feedstock gas bond together (e.g., CO, so that the catalyst loses reaction activity. The performance decay and aging of PEMFC will be influenced by operating conditions, temperature, flow and CO concentration. Therefore, this study proposes the development of an internal real-time wireless diagnostic tool for PEMFC, and uses micro-electro-mechanical systems (MEMS technology to develop a wireless and thin (<50 μm flexible integrated (temperature, flow and CO microsensor. The technical advantages are (1 compactness and three wireless measurement functions; (2 elastic measurement position and accurate embedding; (3 high accuracy and sensitivity and quick response; (4 real-time wireless monitoring of dynamic performance of PEMFC; (5 customized design and development. The flexible integrated microsensor is embedded in the PEMFC, three important physical quantities in the PEMFC, which are the temperature, flow and CO, can be measured simultaneously and instantly, so as to obtain the authentic and complete reaction in the PEMFC to enhance the performance of PEMFC and to prolong the service life.

  4. Nano-Enabled Technologies for Naval Aviation Applications

    Science.gov (United States)

    2015-06-05

    fuel processors 4. Higher operating voltage and thus higher efficiency stacks. 1. High-temp PEMFC systems for UAV power plants 2. High...temp PEMFC systems for APUs 2. Improved high- temperature electrolytes 1. Immobilizing conducting species without...tolerance 4. More compact systems with smaller heat rejection 1. High-temp PEMFC systems for UAV power plants; 2. High-temp PEMFC systems for

  5. Electric generation situation through hybrid systems in Para state and perspectives in face of the global supply of electric power; Situacao da geracao eletrica atraves de sistemas hibridos no estado do Para e perspectivas frente a universalizacao da energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Claudomiro Fabio de Oliveira; Pinho, Joao Tavares; Pereira, Edinaldo Jose da Silva; Galhardo, Marcos Andre Barros; Vale, Silvio Bispo do; Maranhao, Wilson Monteiro de Albuquerque [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Grupo de Estudos e Desenvolvimento de Alternativas Energeticas], e-mail: gedae@ufpa.br

    2004-07-01

    This work presents an analysis of the hybrid systems for electricity generation installed in the State of Para, emphasizing the profile of the supplied localities, the conversion technologies in the several configurations used for electric power generation, the social, economic and environmental impacts caused by such systems, the management and sustainability of the systems, and their perspectives in face of the global supply of electric power in Brazil. (author)

  6. Conclusions and Recommendations Regarding the Deep Sea Hybrid Power Systems Initial Study

    Science.gov (United States)

    2010-06-01

    proton-exchange membrane fuel cells ( PEMFC ) powered with hydrogen and oxygen, similar to that used on proven subsurface vessels; (2) fuel-cells...AND STORAGE OPTIONS CONSIDERED FOR INITIAL STUDY NO. NOMENCLATURE DESCRIPTION 1 PWR Nuclear Reactor + Battery 2 FC1 PEMFC + Line for surface O2...Wellhead Gas + Reformer + Battery 3 FC2 PEMFC + Stored O2 + Wellhead Gas + Reformer + Battery 4 SV1 PEMFC + Submersible Vehicle for O2 Transport

  7. Analysis of proton exchange membrane fuel cell performance with alternate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Wakizoe, Masanobu; Velev, O A; Srinivasan, S [Texas A and M Univ., College Station, TX (United States). Texas Engineering Experiment Station

    1995-02-01

    Renewed interest in proton exchange membrane fuel cell technology for space and terrestrial (particularly electric vehicles) was stimulated by the demonstration, in the mid 1980s, of high energy efficiencies and high power densities. One of the most vital components of the PEMFC is the proton conducting membrane. In this paper, an analysis is made of the performances of PEMFCs with Dupont`s Nafion, Dow`s experimental, and Asahi Chemical`s Aciplex-S membranes. Attempts were also made to draw correlations between the PEMFC performances with the three types of membranes and their physico-chemical characteristics. Practically identical levels of performances (energy efficiency, power density, and lifetime) were achieved in PEMFCs with the Dow and the Aciplex-S membranes and these performances were better than in the PEMFCs with the Nafion-115 membrane. The electrode kinetic parameters for oxygen reduction are better for the PEMFCs with the Aciplex-S and Nafion membranes than with the Dow membranes. The PEMFCs with the Aciplex-S and Dow membranes have nearly the same internal resistances which are considerably lower than for the PEMFC with the Nafion membrane. The desired membrane characteristics to obtain high levels of performance are low equivalent weight and high water content. (Author)

  8. Economic analysis of direct hydrogen PEM fuel cells in three near-term markets

    International Nuclear Information System (INIS)

    Mahadevan, K.; Stone, H.; Judd, K.; Paul, D.

    2007-01-01

    Direct hydrogen polymer electrolyte membrane fuel cells (H-PEMFCs) offer several near-term opportunities including backup power applications in state and local agencies of emergency response; forklifts in high throughput distribution centers; and, airport ground support equipment. This paper presented an analysis of the market requirements for introducing H-PEMFCs successfully, as well as an analysis of the lifecycle costs of H-PEMFCs and competing alternatives in three near-term markets. It also used three scenarios as examples of the potential for market penetration of H-PEMFCs. For each of the three potential opportunities, the paper presented the market requirements, a lifecycle cost analysis, and net present value of the lifecycle costs. A sensitivity analysis of the net present value of the lifecycle costs and of the average annual cost of owning and operating each of the H-PEMFC opportunities was also conducted. It was concluded that H-PEMFC-powered pallet trucks in high-productivity environments represented a promising early opportunity. However, the value of H-PEMFC-powered forklifts compared to existing alternatives was reduced for applications with lower hours of operation and declining labor rates. In addition, H-PEMFC-powered baggage tractors in airports were more expensive than battery-powered baggage tractors on a lifecycle cost basis. 9 tabs., 4 figs

  9. Hawaii Energy and Environmental Technologies (HEET) Initiative

    Science.gov (United States)

    2011-12-01

    polymer electrolyte fuel cells ( PEMFCs ) performance. This work was performed to support the DOE manufacturing initiative for PEMFC production. The work...performed by exposing the MEA cathode to 10 ppm SO2 in N2 at certain potential and typical operating conditions of a PEMFC for certain time, then...adsorbate by analyzing the electrochemical reduction and oxidation potential and charge. As for the in-situ SO2 adsorption experiments, a PEMFC under

  10. CERDEC Fuel Cell Team: Military Transitions for Soldier Fuel Cells

    Science.gov (United States)

    2008-10-27

    Fuel Cell (DMFC) (PEO Soldier) Samsung: 20W DMFC (CRADA) General Atomics & Jadoo: 50W Ammonia Borane Fueled PEMFC Current Fuel Cell Team Efforts...Continued Ardica: 20W Wearable PEMFC operating on Chemical Hydrides Spectrum Brands w/ Rayovac: Hydrogen Generators and Alkaline Fuel Cells for AA...100W Ammonia Borane fueled PEMFC Ultralife: 150W sodium borohydride fueled PEMFC Protonex: 250W RMFC and Power Manager (ARO) NanoDynamics: 250W SOFC

  11. SIMULATION OF POROSITY AND PTFE CONTENT IN GAS DIFFUSION LAYER ON PROTON EXCHANGE MEMBRANE FUEL CELL PERFORMANCE

    Directory of Open Access Journals (Sweden)

    NUR H. MASLAN

    2016-01-01

    Full Text Available Numerous research and development activities have been conducted to optimize the operating parameters of a proton exchange membrane fuel cell (PEMFC by experiments and simulations. This study explains the development of a 3D model by using ANSYS FLUENT 14.5 to determine the optimum PEMFC parameters, namely, porosity and polytetrafluoroethylene (PTFE content, in the gas diffusion layer (GDL. A 3D model was developed to analyze the properties and effects of GDL. Simulation results showed that the increase in GDL porosity significantly improved the performance of PEMFC in generating electrical power. However, the performance of PEMFC decreased with increasing PTFE content in GDL. Thus, the PTFE content in the GDL must be optimized and the optimum PTFE content should be 5 wt%. The model developed in this simulation showed good capability in simulating the PEMFC parameters to assist the development process of PEMFC design.

  12. Overview and benchmark analysis of fuel cell parameters estimation for energy management purposes

    Science.gov (United States)

    Kandidayeni, M.; Macias, A.; Amamou, A. A.; Boulon, L.; Kelouwani, S.; Chaoui, H.

    2018-03-01

    Proton exchange membrane fuel cells (PEMFCs) have become the center of attention for energy conversion in many areas such as automotive industry, where they confront a high dynamic behavior resulting in their characteristics variation. In order to ensure appropriate modeling of PEMFCs, accurate parameters estimation is in demand. However, parameter estimation of PEMFC models is highly challenging due to their multivariate, nonlinear, and complex essence. This paper comprehensively reviews PEMFC models parameters estimation methods with a specific view to online identification algorithms, which are considered as the basis of global energy management strategy design, to estimate the linear and nonlinear parameters of a PEMFC model in real time. In this respect, different PEMFC models with different categories and purposes are discussed first. Subsequently, a thorough investigation of PEMFC parameter estimation methods in the literature is conducted in terms of applicability. Three potential algorithms for online applications, Recursive Least Square (RLS), Kalman filter, and extended Kalman filter (EKF), which has escaped the attention in previous works, have been then utilized to identify the parameters of two well-known semi-empirical models in the literature, Squadrito et al. and Amphlett et al. Ultimately, the achieved results and future challenges are discussed.

  13. Proton exchange fuel cell : the design, construction and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Heinzen, M.R.; Simoes, G.C.; Da Silva, L. [Univ. do Vale do Itajai, Sao Jose, SC (Brazil). Lab. de Pesquisa em Energia; Fiori, M.A.; Paula, M.M.S. [Univ. do Extremo Sul Catarinense, Santa Catarina (Brazil). Lab. de Sintese de Complexos Multifuncionais; Benavides, R. [Centro de Investigacion en Quimica Aplicada, Coahuila (Mexico)

    2010-07-15

    Polymer electrolyte membrane fuel cells (PEMFC) convert the chemical energy stored in the fuel directly into electrical energy without intermediate steps. The PEMFC operates at a relatively low operating temperature making it a good choice for mobile applications, but a high power density is needed in order to decrease the total weight of the vehicles. This paper presented a simple methodology to construct a PEMFC-type fuel cell, with particular reference to the gaseous diffuser, cell structure, the fixing plate, mounting bracket, gas distribution plates, and the membrane electrode assembly (MEA). The geometric design and meshing of the PEMFC were also described. The electrode was made using graphite with flow-field geometry. The PEMFC was tested for 100 hour of continuous work, during which time the current and voltage produced were monitored in order to evaluate the performance of the PEMFC. The materials used in the preparation of the fuel cell proved to be suitable. There was no loss of efficiency during the tests. The most relevant aspects affecting the PEMFC design were examined in an effort to optimize the performance of the cell. 13 refs., 6 figs.

  14. Produção de membranas híbridas zirconizadas de SPEEK/Copolissilsesquioxano para aplicação em células a combustível do tipo PEM

    Directory of Open Access Journals (Sweden)

    Kelen R. Aguiar

    2012-01-01

    Full Text Available Membranas baseadas em poli(aril éter cetona sulfonada mostraram ser bastante promissoras para aplicação em células a combustível com membrana trocadora de prótons (PEMFC. O poli(éter-éter-cetona sulfonado (SPEEK, com elevado grau de sulfonação (GS, apresenta alta condutividade de prótons, mas sofre perda de funcionalidade e condutividade em temperaturas altas e umidades baixas. O desenvolvimento de membranas híbridas é uma das possibilidades para melhorar o desempenho destes materiais. Neste trabalho foram preparadas membranas híbridas zirconizadas de SPEEK/copolissilsesquioxano fosfonado (CF por casting, a partir de SPEEK com GS entre 60% e 70% e soluções de cloreto de zirconila (ZrOCl2 1, 5, ou 10% (m/m. As membranas foram caracterizadas por espectroscopia na região do infravermelho (FTIR, difratometria de raios-X (DRX, análise termogravimétrica (TG, calorimetria exploratória diferencial (DSC, condutividade de prótons (σ e microscopia eletrônica de varredura (MEV. A análise por energia dispersiva (EDS confirmou a presença de Zr em domínios esféricos dispersos homogeneamente pelas membranas, enquanto análises de DRX mostraram que os produtos da zirconização são amorfos. Ensaios de impedância eletroquímica indicam aumento da condutividade protônica com a adição de CF e 1 ou 5% de ZrOCl2.

  15. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Li, Qingfeng

    Polymer electrolyte membrane fuel cell (PEMFC) technology based on Nafion membranes can operate at temperatures around 80°C. The new development in the field is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th......, and system integration of the high temperature PEMFC. The strategic developments of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer, afterburner...... and power management system, that are compatible with the HT-PEMFC; and (3) integration of the HT-PEMFC stack with these compatible subunits. The main goal of the project is a 2kWel HT-PEMFC stack operating in a temperature range of 120-220°C, with a single cell performance target of 0.7 A/cm² at a cell...

  16. A high performance hydrogen/chlorine fuel cell for space power applications

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, E B [PSI Technology Co., A Div. of Physical Sciences Inc., Andover, MA (United States); Taylor, E J [PSI Technology Co., A Div. of Physical Sciences Inc., Andover, MA (United States); Wilemski, G [PSI Technology Co., A Div. of Physical Sciences Inc., Andover, MA (United States); Gelb, A [PSI Technology Co., A Div. of Physical Sciences Inc., Andover, MA (United States)

    1994-01-15

    This article discusses the proton-exchange membrane fuel cell (PEMFC) as a high power and energy density power source. The two systems H{sub 2}/Cl{sub 2} and H{sub 2}/O{sub 2} PEMFC systems were compared over a wide range of mission lifetimes. It has been shown that the development of a H{sub 2}/Cl{sub 2} PEMFC could yield a system with power and energy densities inherently greater than currently available in H{sub 2}/O{sub 2} PEMFC. (orig.)

  17. Evaluation and application of PEMFC fuel cell's technologies developed at IPEN applied to a 500 W{sub e} fuel cell stack; Avaliacao e aplicacao de tecnologias de celulas a combustivel tipo PEMFC desenvolvida no IPEN em um modulo de 500 W{sub e} de potencia nominal

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Edgar Ferrari da

    2009-07-01

    This work is part of a research project on PEMFC technologies carried out in IPEN to develop and optimize a 500 W{sub e} fuel cell stack. The MEAs scaling up from 25 cm{sup 2} to 144 cm{sup 2} produced by the method of sieve printing; computational fluid dynamics by computer simulation of gas flow channels in bipolar plates using COMSOL{sup R} program and the use of Pt/C electrodes developed by alcohol reduction method in single cells were used to build a stack of 500 W{sub e} nominal power for possible commercial applications, produced with national technology and industrial support. A 100 hours fuel cell's test was carried out in a 144 cm{sup 2} single cell to study the stability of the MEA fabricated by sieve printing method. This single cell showed good stability within this period of time. The developed stack has reached the maximum power of 574 W{sub e} at 100 A (694.4 mA cm{sup -2}). The operating power of 500 W{sub e} was obtained at 77.7 A (540.1 mA cm{sup -2}) and potential of 6.43 V, with efficiency of 43.3%. In terms of cogeneration, the thermal power or generated heat by the stack was 652 W{sub t}. The initial estimated cost for the 500 W{sub e} stack was about R$ 4,500.00, considering only the used materials for its construction. (author)

  18. Primary energy savings in desiccant and evaporative cooling-assisted 100% outdoor air system combined with a fuel cell

    International Nuclear Information System (INIS)

    Kim, Min-Hwi; Dong, Hae-Won; Park, Joon-Young; Jeong, Jae-Weon

    2016-01-01

    Highlights: • A LD-IDECOAS integrated with a PEMFC was proposed. • A pilot system was installed and tested during cooling operation. • The proposed system powered by the PEMFC saved 21% of the primary energy consumption during cooling. - Abstract: The main purpose of this study involved investigating the primary energy saving potential of a liquid desiccant and evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS) integrated with a proton exchange membrane fuel cell (PEMFC). During the cooling season, the heat produced by the PEMFC was used to regenerate a weak desiccant solution, and the electricity generated was used to operate the LD-IDECOAS. A pilot LD-IDECOAS powered by a PEMFC was installed and operated in an office space to experimentally verify the annual operating energy savings of the proposed system. The findings indicated that the heat reclaimed from the PEMFC saved 42% of the desiccant solution regenerating energy when compared to that in the case of a conventional gas-fired water heater. The results also suggested that the LD-IDECOAS combined with a PEMFC consumed 21% less primary energy when compared with that of a system powered by grid electricity and a conventional gas-fired water heater.

  19. Heat science and transport phenomena in fuel cells; Thermique et phenomenes de transport dans les piles a combustible

    Energy Technology Data Exchange (ETDEWEB)

    Liberatore, P.M.; Boillot, M. [Laboratoire des Sciences du Genie Chimique de Nancy, 54 - Vandoeuvre-les-Nancy (France); Bonnet, C.; Didieerjean, S.; Lapicque, F.; Deseure, J.; Lottin, O.; Maillet, D.; Oseen-Senda, J. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee, 54 - Vandoeuvre Les Nancy (France); Alexandre, A. [Laboratoire d' Etudes Thermiques, ENSMA, 86 Poitiers (France); Topin, F.; Occelli, R.; Daurelle, J.V. [IUSTI / Polytech' Marseille, Institut universitaire des Systemes Thermiques Industriels Ecole, 13 - Marseille (France); Pauchet, J.; Feidt, M. [CEA Grenoble, Groupement pour la recherche sur les echangeurs thermiques (Greth), 38 (France); Voarino, C. [CEA Centre d' Etudes du Ripault, 37 - Tours (France); Morel, B.; Laurentin, J.; Bultel, Y.; Lefebvre-Joud, F. [CEA Grenoble, LEPMI, 38 (France); Auvity, B.; Lasbet, Y.; Castelain, C.; Peerohossaini, H. [Ecole Centrale de Nantes, Laboratoire de Thermocinetique de Nantes (LTN), 44 - Nantes (France)

    2005-07-01

    In this work are gathered the transparencies of the lectures presented at the conference 'heat science and transport phenomena in fuel cells'. The different lectures have dealt with 1)the gas distribution in the bipolar plates of a fuel cell: experimental studies and computerized simulations 2)two-phase heat distributors in the PEMFC 3)a numerical study of the flow properties of the backing layers on the transfers in a PEMFC 4)modelling of the heat and mass transfers in a PEMFC 5)two-phase cooling of the PEMFC with pentane 6)stationary thermodynamic model of the SOFC in the GECOPAC system 7)modelling of the internal reforming at the anode of the SOFC 8)towards a new thermal design of the PEMFC bipolar plates. (O.M.)

  20. Ionic liquids in proton exchange membrane fuel cells: Efficient systems for energy generation

    Energy Technology Data Exchange (ETDEWEB)

    Padilha, Janine C.; Basso, Juliana; da Trindade, Leticia G.; Martini, Emilse M.A.; de Souza, Michele O.; de Souza, Roberto F. [Institute of Chemistry, UFRGS, Av. Bento Goncalves 9500, Porto Alegre 91501-970, P.O. Box 15003 (Brazil)

    2010-10-01

    Proton exchange membrane fuel cells (PEMFCs) are used in portable devices to generate electrical energy; however, the efficiency of the PEMFC is currently only 40%. This study demonstrates that the efficiency of a PEMFC can be increased to 61% when 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF{sub 4}) ionic liquid (IL) is used together with the membrane electrode assembly (MEA). The results for ionic liquids (ILs) 1-butyl-3-methylimidazolium chloride (BMI.Cl) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF{sub 4}) in aqueous solutions are better than those obtained with pure water. The current and the power densities with IL are at least 50 times higher than those obtained for the PEMFC wetted with pure water. This increase in PEMFC performance can greatly facilitate the use of renewable energy sources. (author)

  1. Evaluation of an integrated methane autothermal reforming and high-temperature proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    Authayanun, Suthida; Saebea, Dang; Patcharavorachot, Yaneeporn; Arpornwichanop, Amornchai

    2015-01-01

    The aim of this study was to investigate the performance and efficiency of an integrated autothermal reforming and HT-PEMFC (high-temperature proton exchange membrane fuel cell) system fueled by methane. Effect of the inclusion of a CO (carbon monoxide) removal process on the integrated HT-PEMFC system was considered. An increase in the S/C (steam-to-carbon) ratio and the reformer temperature can enhance the hydrogen fraction while the CO formation reduces with increasing S/C ratio. The fuel processor efficiency of the methane autothermal reformer with a WGS (water gas shift reactor) reactor, as the CO removal process, is higher than that without a WGS reactor. A higher fuel processor efficiency can be obtained when the feed of the autothermal reformer is preheated to the reformer temperature. Regarding the cell performance, the reformate gas from the methane reformer operated at T in  = T R and with a high S/C ratio is suitable for the HT-PEMFC system without a WGS reactor. When considering the HT-PEMFC system with a WGS reactor, the CO poisoning has less significant impact on the cell performance and the system can be operated over a broader range to minimize the required total active area. A WGS reactor is necessary for the methane autothermal reforming and HT-PEMFC integrated system with regard to the system efficiency. - Highlights: • An integrated autothermal reforming and HT-PEMFC system was studied. • The HT-PEMFC system with and without a CO removal process was considered. • Parametric analysis was performed to obtain a high system efficiency. • The HT-PEMFC system with the WGS reactor can be run over a broader range. • The efficiencies of the HT-PEMFC systems without and with a WGS reactor were reported

  2. Powering the cars and homes of tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Ralph, T R; Hards, G A [Johnson Matthey Technology Centre, Reading (United Kingdom)

    1998-05-04

    Proton exchange membrane fuel cell (PEMFC) technology and its applications are reviewed. As a small, light power source, a PEMFC stack operates at low temperature and high power density, offers fast start-up and low pollution and is ideal for transport applications. PEMFC systems are modular and energy efficient and are being developed as portable power sources (25W-1kW) for the leisure industry and as stationary power units for the home (5-10kW), hotels and hospitals (up to 500kW). Stacks are combined in series or parallel to give the desired power output. Each stack consist of a number of single fuel cells in which the site of the power generation is a membrane electrode assembly less than a millimetre thick. Developments in reducing the cost of PEMFC stacks are described. Over the past few years, successful demonstrations have been carried out, particularly showing the potential cost-effectiveness and low pollution of PEMFC engines for buses and cars. There are aggressive plans to demonstrate PEMFC power plants for the large stationary market. (UK)

  3. Evaluation and application of PEMFC fuel cell's technologies developed at IPEN applied to a 500 W{sub e} fuel cell stack; Avaliacao e aplicacao de tecnologias de celulas a combustivel tipo PEMFC desenvolvida no IPEN em um modulo de 500 W{sub e} de potencia nominal

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Edgar Ferrari da

    2009-07-01

    This work is part of a research project on PEMFC technologies carried out in IPEN to develop and optimize a 500 W{sub e} fuel cell stack. The MEAs scaling up from 25 cm{sup 2} to 144 cm{sup 2} produced by the method of sieve printing; computational fluid dynamics by computer simulation of gas flow channels in bipolar plates using COMSOL{sup R} program and the use of Pt/C electrodes developed by alcohol reduction method in single cells were used to build a stack of 500 W{sub e} nominal power for possible commercial applications, produced with national technology and industrial support. A 100 hours fuel cell's test was carried out in a 144 cm{sup 2} single cell to study the stability of the MEA fabricated by sieve printing method. This single cell showed good stability within this period of time. The developed stack has reached the maximum power of 574 W{sub e} at 100 A (694.4 mA cm{sup -2}). The operating power of 500 W{sub e} was obtained at 77.7 A (540.1 mA cm{sup -2}) and potential of 6.43 V, with efficiency of 43.3%. In terms of cogeneration, the thermal power or generated heat by the stack was 652 W{sub t}. The initial estimated cost for the 500 W{sub e} stack was about R$ 4,500.00, considering only the used materials for its construction. (author)

  4. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf

    The new development in the field of polymer electrolyte membrane fuel cell (PEMFC) is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th framework programme. New challenges are encountered, bottlenecks for the new...... technology have been identified, and new concepts and solutions have been provisionally identified. FURIM is directed at tackling these key issues by concentrating on the further materials development, compatible technologies, and system integration of the high temperature PEMFC. The strategic developments...... of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer and afterburner, that are compatible with the HT-PEMFC; and (3) integration of the HT-PEMFC stack...

  5. A hybrid system using a regenerative electrochemical cycle to harvest waste heat from the proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Long, Rui; Li, Baode; Liu, Zhichun; Liu, Wei

    2015-01-01

    A new hybrid system consisting of a PEMFC (proton exchange membrane fuel cell) subsystem and a TREC (thermally regenerative electrochemical cycle) subsystem is proposed to convert the waste heat produced by the PEMFC system into electricity. The performance of the hybrid system and its corresponding subsystems is analyzed. Results reveal that there exists optimal current densities of the PEMFC and TREC systems leading to the maximum power output of the hybrid system. With the maximum power output as the objective function, an optimization of the hybrid system based on genetic algorithm method is conducted under different operating temperatures of the PEMFC subsystem. The power output of the hybrid system is 6.85%–20.59% larger than that of the PEMFC subsystem. And the total electrical efficiency is improved by 2.74%–8.27%. The corresponding electrical efficiency of the TREC is 4.56%–13.81%. The hybrid system proposed in this paper could contribute to utilizing the fuel energy more efficiently and sufficiently. - Highlights: • A hybrid power system consisting of a PEMFC and a TREC subsystems is proposed. • Parameters' impacts on performance of the hybrid system have been analyzed. • The maximum power output of the hybrid system is investigated based on genetic algorithm. • Total power output of the hybrid system is 7.63%–18.84% larger than that of the PEMFC subsystem.

  6. Exploring Alkaline Stable Organic Cations for Polymer Hydroxide Exchange Membranes

    Science.gov (United States)

    2015-04-29

    1   1.1.2   Proton exchange membrane fuel cells ( PEMFCs ) ......................... 3   1.1.3   Alkaline fuel cells (AFCs...160   xi LIST OF FIGURES Figure 1.1:   Schematic diagram of a PEMFC ...according to the type of electrolyte they use. Nowadays, there are six major types of fuel cells: proton-exchange membrane fuel cells ( PEMFCs ), hydroxide

  7. Development of Novel PEM Membrane and Multiphase CD Modeling of PEM Fuel Cell

    Energy Technology Data Exchange (ETDEWEB)

    K. J. Berry; Susanta Das

    2009-12-30

    To understand heat and water management phenomena better within an operational proton exchange membrane fuel cell's (PEMFC) conditions, a three-dimensional, two-phase computational fluid dynamic (CFD) flow model has been developed and simulated for a complete PEMFC. Both liquid and gas phases are considered in the model by taking into account the gas flow, diffusion, charge transfer, change of phase, electro-osmosis, and electrochemical reactions to understand the overall dynamic behaviors of species within an operating PEMFC. The CFD model is solved numerically under different parametric conditions in terms of water management issues in order to improve cell performance. The results obtained from the CFD two-phase flow model simulations show improvement in cell performance as well as water management under PEMFCs operational conditions as compared to the results of a single phase flow model available in the literature. The quantitative information obtained from the two-phase model simulation results helped to develop a CFD control algorithm for low temperature PEM fuel cell stacks which opens up a route in designing improvement of PEMFC for better operational efficiency and performance. To understand heat and water management phenomena better within an operational proton exchange membrane fuel cell's (PEMFC) conditions, a three-dimensional, two-phase computational fluid dynamic (CFD) flow model has been developed and simulated for a complete PEMFC. Both liquid and gas phases are considered in the model by taking into account the gas flow, diffusion, charge transfer, change of phase, electro-osmosis, and electrochemical reactions to understand the overall dynamic behaviors of species within an operating PEMFC. The CFD model is solved numerically under different parametric conditions in terms of water management issues in order to improve cell performance. The results obtained from the CFD two-phase flow model simulations show improvement in cell

  8. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications.

    Science.gov (United States)

    Houchins, Cassidy; Kleen, Greg J; Spendelow, Jacob S; Kopasz, John; Peterson, David; Garland, Nancy L; Ho, Donna Lee; Marcinkoski, Jason; Martin, Kathi Epping; Tyler, Reginald; Papageorgopoulos, Dimitrios C

    2012-12-18

    Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE) Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C) in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC) and that reduce methanol crossover (DMFC) will be discussed.

  9. Polyarylenethioethersulfone Membranes for Fuel Cells (Postprint)

    Science.gov (United States)

    2010-01-01

    The Electrochemical SocietyProton exchange membrane fuel cells PEMFCs are an attrac- tive power source due to their energy efficiency and...standard in PEMFC technology.3,4 Nafion membranes have a polytetrafluoro- ethylene PTFE backbone, which provides thermal and chemical stability, and...diffusion layers to fabricate MEAs. Single-cell test (H- PEMFC ).— MEAs were positioned in a single-cell fixture with graphite blocks as current

  10. Analysis of Deactivation Mechanism on a Multi-Component Sulfur-Tolerant Steam Reforming Catalyst

    Science.gov (United States)

    2010-08-01

    Alkaline Fuel Cells (AFC) .............................................................................. 4 1.1.2. Proton Exchange Membrane Fuel Cells ( PEMFC ...temperature fuel cells. Alkaline Fuel Cell (AFC), Proton Exchange Membrane Fuel Cell ( PEMFC ), DMFC and Phosphoric Acid Fuel Cell (PAFC) are low...1960s. 1.1.2. Proton Exchange Membrane Fuel Cells ( PEMFC ) Proton exchange membrane fuel cells are said to be the best type of fuel cells to replace

  11. Land 125 - Power Technologies Review

    Science.gov (United States)

    2012-11-01

    Metal Hydride (Battery) PEMFC Proton Exchange Membrane Fuel Cell PNNL Pacific Northwest National Laboratory RF Radio Frequency SLA Sealed Lead...17 Proton exchange membrane fuel cells ( PEMFC ) and direct methanol fuel cells (DMFC) follow this reaction process, while solid...Membrane Fuel Cells ( PEMFC ) The proton exchange membrane fuel cell is one of the simplest forms of fuel cell. It has a solid polymer membrane as the

  12. Separation Method for Oxygen Mass Transport Coefficient in Two Phase Porous Air Electrodes - Transport in Gas and Solid Polymer or Liquid Electrolyte Phases

    Science.gov (United States)

    2013-08-06

    of the problem studied Proton exchange membrane fuel cells ( PEMFCs ) are the most promising candidate systems for alternative electricity...characteristic. The limiting current can be used as a tool to study mass transport phenomena in PEMFC because it can provide experimental data for the...coefficient for PEMFCs under in situ conditions based on the galvanostatic discharge of a cell with an interrupted reactant supply. The results indicated

  13. An Integrated Computational and Experimental Approach Toward the Design of Materials for Fuel Cell Systems

    Science.gov (United States)

    2012-10-01

    13 Based on the limited work done, the best reported ORR chalcogenide electrocatalysts for PEMFC applications can be ranked as follows: MoRuSe... PEMFC catalysts is the durability of the catalyst particles. Particle size distribution tends to shift towards larger particles during the...the design of new materials for applications in PEMFCs . Reference: A more detailed treatment of the topics of this section, Experimental Target 11

  14. Report on Carbon Nano Material Workshop: Challenges and Opportunities

    Science.gov (United States)

    2013-01-22

    trolyte fuel cells ( PEMFCs ) utilize the ability of the catalysts to initiate and maintain the oxygen reduction reaction on the cathode and the fuel...oxidation reaction on the anode. In order to increase the efficiency of the PEMFC catalysts, high-surface-area mesoporous carbons, carbon blacks, carbon...mechanical and thermal properties derived from a three-dimensional intercon- nected nanonetwork structure. The exceptional properties of CAs for PEMFC

  15. Serie: Madera para construcción Acabados para madera

    OpenAIRE

    Sáenz-Muñoz, Marta; Instituto Tecnológico de Costa Rica

    2012-01-01

    Durante mucho tiempo, la madera ha sido utilizada como material de construcción para resolver principalmente objetivos estructurales; sin embargo, actualmente, el uso de la madera ha tomado mucho auge en la estética de las construcciones, para brindar apariencia y calidez. En la actualidad, el mercado ofrece una amplia gama productos para dar diversos “acabados” a la madera, los cuales sirven para resaltar la belleza de algunas de ellas, realzar características como el color y la veta, o bien...

  16. Fuel cell-based CHP system modelling using Artificial Neural Networks aimed at developing techno-economic efficiency maximization control systems

    International Nuclear Information System (INIS)

    Asensio, F.J.; San Martín, J.I.; Zamora, I.; Garcia-Villalobos, J.

    2017-01-01

    This paper focuses on the modelling of the performance of a Polymer Electrolyte Membrane Fuel Cell (PEMFC)-based cogeneration system to integrate it in hybrid and/or connected to grid systems and enable the optimization of the techno-economic efficiency of the system in which it is integrated. To this end, experimental tests on a PEMFC-based cogeneration system of 600 W of electrical power have been performed to train an Artificial Neural Network (ANN). Once the learning of the ANN, it has been able to emulate real operating conditions, such as the cooling water out temperature and the hydrogen consumption of the PEMFC depending on several variables, such as the electric power demanded, temperature of the inlet water flow to the cooling circuit, cooling water flow and the heat demanded to the CHP system. After analysing the results, it is concluded that the presented model reproduces with enough accuracy and precision the performance of the experimented PEMFC, thus enabling the use of the model and the ANN learning methodology to model other PEMFC-based cogeneration systems and integrate them in techno-economic efficiency optimization control systems. - Highlights: • The effect of the energy demand variation on the PEMFC's efficiency is predicted. • The model relies on experimental data obtained from a 600 W PEMFC. • It provides the temperature and the hydrogen consumption with good accuracy. • The range in which the global energy efficiency could be improved is provided.

  17. Polygeneration system based on PEMFC, CPVT and electrolyzer: Dynamic simulation and energetic and economic analysis

    International Nuclear Information System (INIS)

    Calise, Francesco; Figaj, Rafal Damian; Massarotti, Nicola; Mauro, Alessandro; Vanoli, Laura

    2017-01-01

    Highlights: • A novel polygeneration system is presented. • System includes CPVT collectors, PEM fuel cell, absorption chiller and electrolyzer. • The system provides heating/cooling, domestic hot water, electricity, hydrogen and oxygen. • The system simple payback period is 12.5 years, 5.8 years in case of incentive. • The optimal fuel cell nominal power results 100 kW. - Abstract: This paper presents a dynamic simulation model and an energetic and economic analysis of novel polygeneration system. The system integrates: cogenerative Proton Exchange Membrane Fuel Cell (PEMFC), Concentrated PhotoVoltaic-Thermal (CPVT) collectors, alkaline electrolyzer and single-stage LiBr/H_2O absorption chiller. The plant is designed to supply electrical energy, space heating or cooling and domestic hot water for a small university building. The system produces hydrogen and oxygen, the first one is stored and then it is supplied to the fuel cell, while the second one is sold. The electrolyzer system is powered only by the CPVT collectors, only a small amount of the solar electrical energy is available to the user. Such electric energy along with the one produced by the PEM fuel cell are used by the user and/or supplied to the grid. The system is designed and dynamically simulated using TRNSYS software package. This study is based on a model previously developed by the authors. In particular, the system was modified in order to implement the new components (CPVT, alkaline electrolyzer, hydrogen and oxygen system) in this work. Special attention is paid to the control strategy of the proposed system in order to achieve the optimal system configuration. Daily, weekly and yearly results carried out with the dynamic simulation are presented. Finally, a sensitivity analysis was performed in order to determine the system performance as a function of the main design parameters. The energetic and economic analysis shows that the system can ensure significant energy savings and it

  18. Dynamic performance of a high-temperature PEM (proton exchange membrane) fuel cell – Modelling and fuzzy control of purging process

    International Nuclear Information System (INIS)

    Zhang, Caizhi; Liu, Zhitao; Zhang, Xiongwen; Chan, Siew Hwa; Wang, Youyi

    2016-01-01

    To improve fuel utilization of HT-PEMFC (high-temperature proton exchange membrane fuel cell), which normally operates under dead-end mode, with properly periodical purging to flush out the accumulated water vapour in the anode flow-field is necessary, otherwise the performance of HT-PEMFC would drop gradually. In this paper, a semi-empirical dynamic voltage model of HT-PEMFC is developed for controller design purpose via fitting the experimental data and validated with experimental results. Then, a fuzzy controller is designed to schedule the purging based on the obtained model. According to the result, the developed model well reflects transient characteristics of HT-PEMFC voltage and the fuzzy controller offers good performance for purging scheduling under uncertain load demands. - Highlights: • A semi-empirical dynamic voltage model of HT-PEMFC is developed for control design. • The model is developed via fitting and validated with experimental results. • A fuzzy controller is designed to schedule the purging based on the obtained model.

  19. Cationic Polymers Developed for Alkaline Fuel Cell Applications

    Science.gov (United States)

    2015-01-20

    into five categories: proton exchange membrane fuel cell ( PEMFC ), alkaline fuel cell (AFC), molten carbonate fuel cell (MCFC), solid oxide fuel...SOFC and PAFC belong to high temperature fuel cell, which can be applied in stationary power generation. PEMFC and AFC belong to low temperature fuel...function of the polymer electrolyte is to serve as electrolyte to transport ions between electrodes. PEMFC uses a polymer as electrolyte and works

  20. The Role of Non-Conventional Supports for Single-Atom Platinum-Based Catalysts in Fuel-Cell Technology: A Theoretical Surface Science Approach

    Science.gov (United States)

    2013-02-05

    could be a promising catalyst for PEM fuel cells. Introduction: Proton exchange membrane fuel cells ( PEMFCs ) have found wide potential...Unfortunately, due to their high cost and low lifespan, wide-scale commercialization of PEMFCs has been greatly impeded and much effort has been made to...lower its cost as well as to improve its durability over time. In an attempt to alleviate the high-cost associated with conventional PEMFC catalysts

  1. Block Copolymers for Alkaline Fuel Cell Membrane Materials

    Science.gov (United States)

    2014-07-30

    temperature fuel cells including proton exchange membrane fuel cell ( PEMFC ) and alkaline fuel cell (AFC) with operation temperature usually lower than 120...advantages over proton exchange membrane fuel cells ( PEMFCs ) resulting in the popularity of AFCs in the US space program.[8-11] The primary benefit AFC...offered over PEMFC is better electrochemical kinetics on the anode and cathode under the alkaline environment, which results in the ability to use

  2. Durability and Performance of Polystyrene-b-Poly(vinylbenzyl trimethylammonium) Diblock Copolymer and Equivalent Blend Anion Exchange Membranes

    Science.gov (United States)

    2015-01-01

    requiring circulation of the electrolyte to filter out the carbonate solids. The superior power density of proton exchange membrane fuel cells ( PEMFC ...without requir- ing a CO2 free oxidant stream, prevented commercial develop- ment of the liquid AFC, allowing PEMFCs to dominate low temperature fuel...cell research and development. PEMFCs employ a solid acidic polymer to transport protons from anode to cathode. PEMs have been researched heavily the

  3. The SPRING Nanoenergetics Hub at UTD

    Science.gov (United States)

    2008-12-01

    Proton conductivity 1. Introduction Proton exchange membrane fuel cells ( PEMFC ) are consid- ered as promising alternatives to traditional internal...startup and environmental friendliness [1], The proton exchange membrane (PEM) is the central part in a PEMFC system and has a major influence on the...bility and performance over other available materials, and are therefore used as the "standard" PEM material in the current PEMFCs . Since PFSA

  4. Preliminary Design of an Autonomous Underwater Vehicle Using Multi-Objective Optimization

    Science.gov (United States)

    2014-03-01

    fuel cell PC propulsive coefficient PEMFC proton exchange membrane fuel cell PHP propulsive horsepower PO Pareto optimal PSO particle swarm...membrane fuel cell ( PEMFC ), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC) and direct and indirect methanol fuel cell (DMFC). Figure...of fuel cells in depth, I will note that PEMFCs are smaller and have a lower operating temperature compared to the other types. Those are the main

  5. An air-breathing single cell small proton exchange membrane fuel cell system with AB5-type metal hydride and an ultra-low voltage input boost converter

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Kazuya; Matsumoto, Satoshi; Miyasaka, Akihiro; Shodai, Takahisa [NTT Energy and Environment System Laboratories, 3-1 Morinosato-Wakamiya Atsugi-shi, Kanagawa (Japan)

    2009-01-01

    A new strategy for increasing the power density of an air-breathing small proton exchange membrane fuel cell (PEMFC) system for the main energy source of portable consumer electronics is presented. The small PEMFC system is composed of a single cell. Utilizing the output voltage of the single cell, we introduce a newly designed ultra-low voltage input boost converter. The boost converter can generate 4.1 V output from input sources with low voltage ranges, such as under 1.0 V. The cathode plate is made from a thin SUS 316L stainless steel plate and has ribs that prevent the cathode from bending. The hydrogen is supplied by a metal hydride (MH) tank cartridge. The MH tank contains highly packed AB5-type MH. The MH tank cartridge has a volume of 13.2 cm{sup 3} and can absorb 6.7 L of hydrogen. The maximum power of the small PEMFC is 4.42 W at room temperature. Using 6.7 L of hydrogen, the small PEMFC can generate 11 Wh of electricity. The power density of the small PEMFC reaches 0.51 Wh cm{sup -3}. And the power density of the whole small PEMFC system, which contains the boost converter, a small Li-ion battery for a load absorber, and a case for the system, reaches 0.14 Wh cm{sup -3}. This value matches that of external Li-ion battery chargers for cell phones. We installed the small PEMFC system in a cell phone and confirmed the operations of calling, receiving, videophone, connecting to the Internet, and watching digital TV. And also confirmed that the small PEMFC system provides approximately 8.25 h of talk time, which is about three times as long as that for the original Li-ion battery. (author)

  6. Produção de membranas híbridas zirconizadas de SPEEK/Copolissilsesquioxano para aplicação em células a combustível do tipo PEM Production of Zirconized SPEEK/Copolysilsesquioxane hybrid membranes for application in Proton Exchange Membrane fuel cells

    Directory of Open Access Journals (Sweden)

    Kelen R. Aguiar

    2012-01-01

    Full Text Available Membranas baseadas em poli(aril éter cetona sulfonada mostraram ser bastante promissoras para aplicação em células a combustível com membrana trocadora de prótons (PEMFC. O poli(éter-éter-cetona sulfonado (SPEEK, com elevado grau de sulfonação (GS, apresenta alta condutividade de prótons, mas sofre perda de funcionalidade e condutividade em temperaturas altas e umidades baixas. O desenvolvimento de membranas híbridas é uma das possibilidades para melhorar o desempenho destes materiais. Neste trabalho foram preparadas membranas híbridas zirconizadas de SPEEK/copolissilsesquioxano fosfonado (CF por casting, a partir de SPEEK com GS entre 60% e 70% e soluções de cloreto de zirconila (ZrOCl2 1, 5, ou 10% (m/m. As membranas foram caracterizadas por espectroscopia na região do infravermelho (FTIR, difratometria de raios-X (DRX, análise termogravimétrica (TG, calorimetria exploratória diferencial (DSC, condutividade de prótons (σ e microscopia eletrônica de varredura (MEV. A análise por energia dispersiva (EDS confirmou a presença de Zr em domínios esféricos dispersos homogeneamente pelas membranas, enquanto análises de DRX mostraram que os produtos da zirconização são amorfos. Ensaios de impedância eletroquímica indicam aumento da condutividade protônica com a adição de CF e 1 ou 5% de ZrOCl2.Membranes based on sulfonated poly(aryl ether ketone are known to be very promising materials for Proton Exchange Membrane Fuel Cells (PEMFC. Sulfonated poly(ether-ether-ketone (SPEEK, with high sulfonation degrees (SD, present high proton conductivity. However, they lose functionality and conductivity at high temperatures and low humidity. To enhance the performance of these materials, hybrid membranes have gained considerable attention. In this work, zirconized SPEEK/phosphonated copolysilsesquioxane (CF hybrid membranes were prepared by casting, from SPEEK (60% < SD < 70% and 1, 5, or 10 wt. (% zirconyl chloride solutions

  7. U.S. DOE Progress Towards Developing Low-Cost, High Performance, Durable Polymer Electrolyte Membranes for Fuel Cell Applications

    Directory of Open Access Journals (Sweden)

    Dimitrios C. Papageorgopoulos

    2012-12-01

    Full Text Available Low cost, durable, and selective membranes with high ionic conductivity are a priority need for wide-spread adoption of polymer electrolyte membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs. Electrolyte membranes are a major cost component of PEMFC stacks at low production volumes. PEMFC membranes also impose limitations on fuel cell system operating conditions that add system complexity and cost. Reactant gas and fuel permeation through the membrane leads to decreased fuel cell performance, loss of efficiency, and reduced durability in both PEMFCs and DMFCs. To address these challenges, the U.S. Department of Energy (DOE Fuel Cell Technologies Program, in the Office of Energy Efficiency and Renewable Energy, supports research and development aimed at improving ion exchange membranes for fuel cells. For PEMFCs, efforts are primarily focused on developing materials for higher temperature operation (up to 120 °C in automotive applications. For DMFCs, efforts are focused on developing membranes with reduced methanol permeability. In this paper, the recently revised DOE membrane targets, strategies, and highlights of DOE-funded projects to develop new, inexpensive membranes that have good performance in hot and dry conditions (PEMFC and that reduce methanol crossover (DMFC will be discussed.

  8. Experimentally and numerically investigating cell performance and localized characteristics for a high-temperature proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Su Ay; Ferng, Yuh Ming; Shih, Jah Ching

    2009-01-01

    This paper is to experimentally and numerically investigate the cell performance and the localized characteristics associated with a high-temperature proton exchange membrane fuel cell (PEMFC). Three experiments are carried out in order to study the performance of the PEMFC with different operating conditions and to validate the numerical simulation model. The model proposed herein is a three-dimensional (3-D) computational fluid dynamics (CFD) non-isothermal model that essentially consists of thermal-hydraulic equations and electrochemical model. The performance curves of the PEMFC predicted by the present model agree with the experimental measured data. In addition, both the experiments and the predictions precisely demonstrate the enhanced effects of inlet gas temperature and system pressure on the PEMFC performance. Based on the simulation results, the localized characteristics within a PEMFC can be reasonably captured. These parameters include the fuel gas distribution, liquid water saturation distribution, membrane conductivity distribution, temperature variation, and current density distribution etc. As the PEMFC is operated at the higher current density, the fuel gas would be insufficiently supplied to the catalyst layer, consequently causing the decline in the generation of power density. This phenomenon is so called mass transfer limitation, which can be precisely simulated by the present CFD model.

  9. Design of Conventional Submarines with Advanced Air Independent Propulsion Systems and Determination of Corresponding Theater-Level Impacts

    Science.gov (United States)

    2010-01-01

    rescue vehicle e: Error term ft: Feet HDW: Howaldtswerke- Deutsche Werft GmbH PEMFC : Proton exchange membrane fuel cells IR: Indiscretion rate/ratio...engines &Rankine cycle power plants &Closed cycle engines A PEMFC AIP system is fitted in the 212 class of submarines that German shipbuilders How...bines a conventional system consisting of a diesel engine and a lead acid battery, with the PEMFC AIP system used for slow, silent cruising. The AIP

  10. Conceptual Design Tool for Fuel-Cell Powered Micro Air Vehicles

    Science.gov (United States)

    2010-03-01

    Electrolyte Membrane PEMFC PEM Fuel Cell RAM Rapid Aircraft Modeler R/C Radio Controlled RMFC Reformed Methanol Fuel Cell SBIR Small Business...of rechargeable batteries, the Proton Exchange Membrane Fuel Cell ( PEMFC ) is only limited by the amount of hydrogen it can store, and can be...of fuel cells within MAVs through the creation of the Hornet. This slightly heavier, 380 g MAV integrated a 10 W PEMFC into the wing surface for a

  11. Electrochemically Promoted Organic Isomerization Reactions at Polymer Electrolyte Fuel Cell Cathodes

    Science.gov (United States)

    2011-01-04

    fuel cells ( PEMFCs ) incorporate an ionomer membrane (e.g., Nafion 117) for support of electro- catalytic layers and proton conduction between the...central to PEMFC electrocatalysis. For example, a spin coated Nafion layer on polycrystalline Pt enhances electrocatalysis.7,8 Little is known about...CO Poisoning Effect in PEMFCs Operational at Temperatures up to 200°C. Journal of the Electrochemical Society, 2003. 150(12): p. A1599-A1605. 21

  12. International Assessment of Research and Development in Catalysis by Nanostructured Materials

    Science.gov (United States)

    2009-01-01

    can severely and irreversibly poison downstream catalysts, including those used in ammonia synthesis and proton exchange membrane fuel cells ( PEMFC ...membrane fuel cells ( PEMFC ), solid oxide fuel cells (SOFC), as well as molten carbonate, direct methanol, and direct carbon fuel cells. Much of the work...see site report, Appendix C) are developing methods to disperse Pt on Au cores for use in PEMFCs (Zhao, Wu, and Xu 2005; Zhao and Xu 2006). This

  13. Insights on the SO2 Poisoning of Pt3Co/VC and Pt/VC Fuel Cell Catalysts

    Science.gov (United States)

    2010-01-01

    catalyst is performed at the cathode of proton exchange membrane fuel cells ( PEMFCs ) in order to link previously reported results at the elec- trode...stripping voltammetry and underpotential deposition (upd) of copper adatoms. Then the performance of PEMFC cathodes employing 30wt.% Pt3Co/VC and 50wt.% Pt/VC...proton exchange membrane fuel cells( PEMFCs )in order to link previously reported results at the elec- trode/solution interface to the FC environment. First

  14. Para-bosons and Para-fermions in Quantum Mechanics

    International Nuclear Information System (INIS)

    Cattani, M.S.D.; Fernandes, N.C.

    1982-01-01

    Within the framework of the ordinary quantum mechanics, a detailed study of the energy eigenfunctions of N identical particles using the irreducible representations of the permutation group in the Hilbert space is performed. It is shown that the para-states, as occurs with the boson and fermion states, are compatible with the postulates of quantum mechanics and with the principle of indistinguishability. A mathematical support for the existence of para-bosons and para-fermions is given. Gentile's quantum statistics is, in a certain sense, justified. (Author) [pt

  15. Oxidação de etanol em temperaturas elevadas

    OpenAIRE

    Bruno Alarcon Fernandes Previdello

    2009-01-01

    Atualmente existe um grande interesse mundial na substituição de produtos obtidos a partir do petróleo para o desenvolvimento de novos materiais a partir de fontes renováveis. Neste contexto, o estudo de células a combustível (Fuel Cell) tem recebido destaque em pesquisas tecnológicas. O uso de células a combustível como membrana trocadora de prótons (PEMFC) é uma das mais promissoras. A célula a combustível é um sistema eletroquímico que transforma diretamente energia química a partir de u...

  16. Understanding the Oxygen Reduction Reaction on a Y/Pt(111) Single Crystal

    DEFF Research Database (Denmark)

    Ulrikkeholm, Elisabeth Therese; Johansson, Tobias Peter; Malacrida, Paolo

    2014-01-01

    Polymer electrolyte membrane fuel cells (PEMFC) hold promise as a zero-emission source of power, particularly suitable for automotive vehicles. However, the high loading of Pt required to catalyse the oxygen reduction reaction (ORR) at the PEMFC cathode, prevents the commercialisation of this tec......Polymer electrolyte membrane fuel cells (PEMFC) hold promise as a zero-emission source of power, particularly suitable for automotive vehicles. However, the high loading of Pt required to catalyse the oxygen reduction reaction (ORR) at the PEMFC cathode, prevents the commercialisation...... using electrochemical measurements, low energy electron diffraction, ion scattering spectroscopy, angle resolved X-ray photoelectron spectroscopy, temperature programmed desorption of CO, and synchrotron based X-ray absorption spectroscopy and surface sensitive X-ray diffraction. These measurements were...

  17. Energy Conversion Efficiency Potential for Forward-Deployed Generation Using Direct Carbon Fuel Cells

    Science.gov (United States)

    2012-05-01

    fuel cells vs. DCFCs. PEMFC PAFC MCFC SOFC DCFC Electrolyte Polymer Phosphoric acid Molten car- bonate salt Ceramic Fused KNO3 Operating...air O2/air CO2/O2/air O2/air Humidified air Efficiency (Higher Heating Value [HHV]) 30–35% 40–50% 50–60% 45–55% 80% PEMFC : Proton Exchange... PEMFC proton-exchange membrane fuel cell SOFC solid oxide fuel cell SRI Statistical Research, Inc. TR technical report TRL technology readiness level

  18. Special Issue on Powering the Future Force: New Power & Energy Technologies for the Warfighter (AMMTIAC Quarterly, Volume 4, Number 1 / WSTIAC Quarterly, Volume 9, Number 1)

    Science.gov (United States)

    2009-04-27

    material that has sulfonic acid groups. The sulfonic groups facilitate ionic conduction under hydrated conditions. The operating temperature for PEMFCs ...DMFCs) are a subset of PEMFCs . These FCs utilize the same electrolyte material, but use a differ- ent fuel source (i.e., methanol) and thus a different... PEMFC .[47] 1 Hydrogen fuel is channeled through field flow plates to the anode on one side of the fuel cell, while oxygen from the air is channeled to the

  19. A Hybrid Approach to Tactical Vehicles

    Science.gov (United States)

    2011-09-01

    membrane fuel cell ( PEMFC ), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC), phosphoric acid fuel cell (PAFC), alkaline fuel cell (AFC...and the direct methanol fuel cell (DMFC) (Ehsani, Gao, & Emadi, 2010). Of the six major types of fuel cells; the PEMFC , SOFC, and AFC are... PEMFC (21st Century Truck Program, 2000). There are a number of advantages of using a fuel cell as the primary power source for a vehicle. All fuel

  20. New Fluorinated and Sulfonated Block Copolymers Final Report

    Science.gov (United States)

    2009-04-23

    use polymers namely, Polymer Electrolyte Membrane Fuel Cells ( PEMFC ) and Direct Methanol Fuel Cells (DMFC) The DMFC can be seen as a variant of...the PEMFC . The membranes are typically the same; however, the feed for DMFC is methanol in an aqueous 1-2 M solution or in its vapor form. This fuel...the existing liquid fuels infrastructure can be used for methanol. Catalysts, as well as operating temperature ranges, are very similar to the PEMFC

  1. Lifecycle Cost Assessment of Fuel Cell Technologies for Soldier Power System Applications. Paper and Presentation for the 43rd Power Sources Conference held 8-9 July 2008, Philadelphia, PA

    Science.gov (United States)

    2008-07-09

    PEMFC in Federal Markets,” 2007 Fuel Cell Seminar, San Antonio, TX, 17 October 2007. 7. Fok, K., “Metal Hydride Fuel Cells: Increases in Power...Lauderdale, FL, March 17-20, 2008. 10. Zhao J., et al, “Reclaim/recycle of Pt/C catalysts for PEMFC ,” Energy Conversion and Management, vol. 48...hydrogen PEMFC or SOFC systems – Baratto et al, Journal of Power Sources – Citigroup, Dist. Telecom Backup – Battelle, Fuel Cell Seminar 2007 • Fuel

  2. TechSolutions 11: An Introduction to Power and Energy

    Science.gov (United States)

    2009-01-01

    facilitate ionic conduction under hydrated conditions. The operating temperature for PEMFCs is relatively cool (70°C). The reactions on the anode and...cathode side of the FC are the same as those shown for PAFCs. Direct methanol fuel cells (DMFCs) are a subset of PEMFCs . These FCs utilize the same...an electrically E58 The AMMTIAC Quarterly, Volume 4, Number 1 Figure 7. Diagram of a PEMFC .[47] 1 Hydrogen fuel is channeled through field flow

  3. Wavelet-Transform-Based Power Management of Hybrid Vehicles with Multiple On-board Energy Sources Including Fuel Cell, Battery and Ultracapacitor

    Science.gov (United States)

    2008-09-12

    considered to be promising for application as distributed generation sources due to high efficiency and compactness [1-2], [21-24]. The PEMFC is...also a primary candidate for environment-friendly vehicles. The nomenclatures of the PEMFC are as follows: B , C : Constants to calculate the...0 O H H-O H-O 1 2 N I q q r r FU = (10) The block diagram of the PEMFC model based on the above equations is shown in Fig

  4. Improving the Durability of Methanol Oxidation Reaction Electro-Catalysts Through the Modification of Carbon Architectures

    Science.gov (United States)

    2014-01-01

    PEMFC Direct Methanol Fuel Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DMFC Colorado School of Mines...Thus, a methanol-fed proton exchange membrane fuel cell ( PEMFC ) utilizing this potentially inexpensive fuel, would provide a sustainable and renewable

  5. The effect of channel flow pattern on internal properties distribution of a proton exchange membrane fuel cell for cathode starvation conditions

    International Nuclear Information System (INIS)

    Ko, Dong Soo; Kang, Young Min; Yang, Jang Sik; Jeong, Ji Hwan; Choi, Gyung Min; Kim, Duck Jool

    2010-01-01

    The effect of channel flow pattern on the internal properties distribution of a proton exchange membrane fuel cell (PEMFC) for cathode starvation conditions in a unit cell was investigated through numerical studies and experiments. The polarization curves of a lab-scale mixed serpentine PEMFC were measured with increasing current loads for different cell temperatures (40, 50, and 60 .deg. C) at a relative humidity of 100%. To study the local temperature on the membrane, the water content in the MEA, and the gas velocity in terms of the channel type of the PEMFC with operating characteristics, numerical studies using the es-pemfc module of STAR-CD, which have been matched to the experimental data, were conducted in detail. The water content and velocity at the cathode channel bend of the mixed serpentine channel were relatively higher than those at the single and double channels. Conversely, the local temperature and mean temperature on the membrane of a single serpentine channel were the highest among all channels. These results can be used to design the PEMFC system, the channel flow field, and the cooling device

  6. Recent Progress on the Key Materials and Components for Proton Exchange Membrane Fuel Cells in Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Cheng Wang

    2016-07-01

    Full Text Available Fuel cells are the most clean and efficient power source for vehicles. In particular, proton exchange membrane fuel cells (PEMFCs are the most promising candidate for automobile applications due to their rapid start-up and low-temperature operation. Through extensive global research efforts in the latest decade, the performance of PEMFCs, including energy efficiency, volumetric and mass power density, and low temperature startup ability, have achieved significant breakthroughs. In 2014, fuel cell powered vehicles were introduced into the market by several prominent vehicle companies. However, the low durability and high cost of PEMFC systems are still the main obstacles for large-scale industrialization of this technology. The key materials and components used in PEMFCs greatly affect their durability and cost. In this review, the technical progress of key materials and components for PEMFCs has been summarized and critically discussed, including topics such as the membrane, catalyst layer, gas diffusion layer, and bipolar plate. The development of high-durability processing technologies is also introduced. Finally, this review is concluded with personal perspectives on the future research directions of this area.

  7. Marcadores para la Realidad Aumentada para fines educativos

    Directory of Open Access Journals (Sweden)

    María Reina Zarate Nava

    2013-12-01

    Full Text Available La Realidad Aumentada (AR es considerada por algunos expertos como la tecnología en crecimiento para el 2014, en diferentes sectores: ingeniería, educación, juegos y negocios, siendo este último el más usado en él 2013. Sin embargo en el sector educativo la AR se presenta en algunos proyectos que se han desarrollado para diferentes áreas de las ciencias, como Química, Física y Matemáticas, lo anterior con el objetivo de facilitar el proceso de Enseñanza-Aprendizaje. En el presente artículo se presenta el modelo de patrones utilizado para un Proyecto AR enfocado en Química, el cual presenta un conjunto de patrones que fueron valorados para facilitar el rastreo de los objetos y a su vez el entendimiento de algunos materiales de los laboratorios de Química I.

  8. Degradation modeling and operational optimization for improving the lifetime of high-temperature PEM (proton exchange membrane) fuel cells

    International Nuclear Information System (INIS)

    Kim, Jintae; Kim, Minjin; Kang, Taegon; Sohn, Young-Jun; Song, Taewon; Choi, Kyoung Hwan

    2014-01-01

    High-temperature PEMFCs (proton exchange membrane fuel cells) using PA (phosphoric acid)-doped PBI (polybenzimidazole) membranes have received attention as a potential solution to several of the issues with traditional low-temperature PEMFCs. However, the durability of high-temperature PEMFCs deteriorates rapidly with increasing temperature, although its performance improves. This characteristic makes it difficult to select the proper operating temperature to achieve its target lifetime. In this paper, to resolve this problem, models were developed to predict the performance and durability of the high-temperature PEMFC as a function of operating temperature. The optimal operating temperature was then determined for a variety of lifetimes. Theoretical model to estimate cell performance and empirical model to predict the degradation rate of cell performance were constructed, respectively. The prediction results of the developed models agreed well with the experimental data. From the simulation, we could obtain higher average cell performances by optimizing the operating temperature for the given target lifetime compared to the cell performance at some temperatures determined using an existing rule of thumb. It is expected that the proposed methodologies will lead to the more rapid commercialization of this technology in such applications as stationary and automotive fuel cell systems. - Highlights: • High-temperature PEMFCs (proton exchange membrane fuel cells). • Operational optimization for improving the lifetime. • Development of the degradation modeling for high-temperature PEMFCs

  9. Generating para-water from para-hydrogen: A Gedankenexperiment.

    Science.gov (United States)

    Ivanov, Konstantin L; Bodenhausen, Geoffrey

    2018-07-01

    A novel conceptual approach is described that is based on the transfer of hyperpolarization from para-hydrogen in view of generating a population imbalance between the two spin isomers of H 2 O. The approach is analogous to SABRE (Signal Amplification By Reversible Exchange) and makes use of the transfer of spin order from para-hydrogen to H 2 O in a hypothetical organometallic complex. The spin order transfer is expected to be most efficient at avoided level crossings. The highest achievable enrichment levels of para- and ortho-water are discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Molybdenum Carbide Synthesis Using Plasmas for Fuel Cells

    Science.gov (United States)

    2013-06-01

    S. A. Hong, I. H. Oh, and S. J. Shin, “Performance and life time analysis of the kW-class PEMFC stack,” Journal of Power Sources, vol. 106, pp. 295...pp. 591–596, 1998. [25] M. Gotz and H. Wendt, “Binary and ternary anode catalyst formulations including the elements W, Sn and Mo for PEMFCs ...and R. C. Urian, “Electrocatalysis of CO Tolerance by Carbon-Supported PtMo Electrocatalysts in PEMFCs ,” Journal of Electrochemical Society, vol

  11. High-performance membrane-electrode assembly with an optimal polytetrafluoroethylene content for high-temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Jeong, Gisu; Kim, MinJoong; Han, Junyoung

    2016-01-01

    Although high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) have a high carbon monoxide tolerance and allow for efficient water management, their practical applications are limited due to their lower performance than conventional low-temperature PEMFCs. Herein, we present a high......-performance membrane-electrode assembly (MEA) with an optimal polytetrafluoroethylene (PTFE) content for HT-PEMFCs. Low or excess PTFE content in the electrode leads to an inefficient electrolyte distribution or severe catalyst agglomeration, respectively, which hinder the formation of triple phase boundaries...

  12. Proton-Exchange-Membrane Fuel Cell Powerplants Developed and Tested for Exploration Missions

    Science.gov (United States)

    Hoberecht, Mark A.; Pham, Nang T.

    2005-01-01

    Proton-exchange-membrane fuel cell (PEMFC) technology has received major attention for terrestrial applications, such as the automotive and residential markets, for the past 20 years. This attention has significantly advanced the maturity of the technology, resulting in ever more compact, efficient, reliable, and inexpensive PEMFC designs. In comparison to the terrestrial operating environment, the space operating environment is much more demanding. Microgravity to high-gravity loads and the need to use pure oxygen (rather than air) as the fuel cell oxidizer place more stringent demands on PEMFC technology. NASA and its partners from industry are leveraging terrestrial PEMFC advancements by conducting parallel space technology development for future exploration missions. A team from the NASA Glenn Research Center, NASA Johnson Space Center, and NASA Kennedy Space Center recently completed the first phase of a PEMFC powerplant development effort for exploration missions. The industry partners for this phase of the development effort were ElectroChem, Inc., and Teledyne Energy Systems, Inc. Under contract to Glenn, both of these industry partners successfully designed, fabricated, and tested a breadboard PEMFC powerplant in the 1- to 5-kW power range. These powerplants were based on existing company-proprietary fuel cell stack designs, combined with off-the-shelf components, which formed the balance of the powerplant design. Subsequent to the contractor development efforts, both powerplants were independently tested at Johnson to verify operational and performance characteristics, and to determine suitability for further technology development in the second phase of the NASA-led effort. Following the independent NASA testing, Teledyne Energy Systems, Inc., was selected to develop an engineering model PEMFC powerplant. This effort was initiated by the 2nd Generation Reusable Launch Vehicle (RLV) Program Office in 2001; it transitioned to the Next Generation Launch

  13. Proton-Exchange-Membrane Fuel Cell Powerplants Developed and Tested for Exploration Missions

    Science.gov (United States)

    Hoberecht, Mark A.; Pham, Nang T.

    2005-06-01

    Proton-exchange-membrane fuel cell (PEMFC) technology has received major attention for terrestrial applications, such as the automotive and residential markets, for the past 20 years. This attention has significantly advanced the maturity of the technology, resulting in ever more compact, efficient, reliable, and inexpensive PEMFC designs. In comparison to the terrestrial operating environment, the space operating environment is much more demanding. Microgravity to high-gravity loads and the need to use pure oxygen (rather than air) as the fuel cell oxidizer place more stringent demands on PEMFC technology. NASA and its partners from industry are leveraging terrestrial PEMFC advancements by conducting parallel space technology development for future exploration missions. A team from the NASA Glenn Research Center, NASA Johnson Space Center, and NASA Kennedy Space Center recently completed the first phase of a PEMFC powerplant development effort for exploration missions. The industry partners for this phase of the development effort were ElectroChem, Inc., and Teledyne Energy Systems, Inc. Under contract to Glenn, both of these industry partners successfully designed, fabricated, and tested a breadboard PEMFC powerplant in the 1- to 5-kW power range. These powerplants were based on existing company-proprietary fuel cell stack designs, combined with off-the-shelf components, which formed the balance of the powerplant design. Subsequent to the contractor development efforts, both powerplants were independently tested at Johnson to verify operational and performance characteristics, and to determine suitability for further technology development in the second phase of the NASA-led effort. Following the independent NASA testing, Teledyne Energy Systems, Inc., was selected to develop an engineering model PEMFC powerplant. This effort was initiated by the 2nd Generation Reusable Launch Vehicle (RLV) Program Office in 2001; it transitioned to the Next Generation Launch

  14. Fuel cell electrodes: Electrochemical characterization and electrodeposition of Pt nanoparticles

    CSIR Research Space (South Africa)

    Modibedi, M

    2008-05-01

    Full Text Available Fuel Cell (PEMFC) Electrolyte: solid polymer membrane (typically Nafion) Types of fuel cells (FC) ? CSIR 2007 www.csir.co.za PEMFC http://fuelcellsworks.com/ ? CSIR 2007 www.csir.co.za Electrodes...

  15. Analysis for impedance electrochemistry 'on-line' of membrane/electrode assemble (MEA) of protons exchange membrane fuel cells (PEMFC); Analise por impedancia eletroquimica 'on-line' de conjuntos eletrodos/membrana (MEA) de celulas a combustivel a membrana polimetrica (PEMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Antonio Rodolfo dos

    2007-07-01

    This work reports results of studies and characterization on membrane electrode assemblies (MEAs) for proton exchange membrane fuel cell (PEMFC). Some cell operation conditions and different processes of MEA production were investigated. The electrochemical impedance spectroscopy technique (EIS) (in situ - 0 to 16 A) was used 'on-line' as a tool for diagnosis, concerning the cell performance. The EIS measurements were carried out with a FC350 Fuel Cell EIS System (GAMRY), coupled to a PC4 potentiostat/galvanostat and connected to the electronic load (TDI) for 'on-line' EIS experiments (100 mHz - 10 kHz, dU = 5 mV). MEAs with 25 cm{sup 2} surface area, using PtM/C 20% (M Ru, Sn or Ni) electrocatalysts were manufactured using the alcohol reduction process (ARP). The catalytic ink was applied directly into the carbon cloth (GDL) and pressed in the Nafion membrane (105). MEAs using Pt/C and Pt Ru/C 20% from E-TEK electrocatalysts were manufactured by comparison. All the cathodes were sprayed with Pt/C 20% from E-TEK. The noble metal concentrations used were set to 0.4 mg Pt.cm{sup -2} at the anode and 0.6 mg Pt.cm{sup -2} at the cathode (E-TEK). Nyquist diagrams of the MEAs with Pt/C and PtRu/C from E-TEK or PtM/C (M = Ru, Sn or Ni) ARP showed essentially the same ohmic resistances for the MEAs. This fact can be explained by suppression of agglomerates during the MEA preparation process or by the homogeneity of the anchored electrocatalysts at the carbon surface. It could also be observed, at low current densities, that there was a significant performance difference between the electrocatalysts from E-TEK and those prepared with the alcohol reduction process. The polarization curves results confirmed that the Pt M/C (M = Ru, Sn or Ni) ARP showed an activity increase for the methanol and ethanol fed cells. The technique of EIE was shown efficient for the evaluation of the method preparation of MEAs and the acting of the cell, the results of EIE showed coherence in the

  16. Uma ferramenta para planejamento de estudos para concursos

    Directory of Open Access Journals (Sweden)

    Leonardo Pimentel

    2015-11-01

    Full Text Available De acordo com a constituição brasileira, a única forma de se tornar um empregado do governo é passar em um concurso público. O exame de conhecimento do cargo é um dos componentes mais importantes de um concurso. Estudar para esse exame é uma tarefa que requer planejamento. Um meio de obter um bom planejamento é construir uma grade de horários que relacione as matérias a serem estudadas com os respectivos horários disponíveis para o estudo. Esse tipo de problema se assemelha bastante à gerência de projetos, em que se procura estabelecer a distribuição das atividades ao longo do tempo disponível. Assim, torna-se interessante explorar a dinâmica de estudos para concursos como um projeto. O presente trabalho apresenta a ferramenta de apoio ao estudos - Passe-me, baseada no ciclo PDCA (do inglês, Plan-Do-Check-Act. Por se tratar de uma ferramenta web, o tempo de resposta para produzir uma grade de estudos é fundamental. A ferramenta faz uso de algoritmo genético para calcular a grade de horários priorizando a velocidade de resposta. A ferramenta foi avaliada em diferentes cenários de uso e obteve desempenho satisfatório durante a produção da grade de estudos.

  17. Docencia para el logro y educación para emprender

    Directory of Open Access Journals (Sweden)

    Luis Gerardo Rodríguez Gómez

    1994-05-01

    Full Text Available RESUMEN En el primer artículo, el autor plasmó los elementos relevantes para una propuesta de educación para emprender. En este describe el desarrollo docente como expresión de una intensión, saber y un quehacer, encaminados a la formación del hombre emprendedor. El artículo se divide en tres partes. En la primera, se reseña los factores que orientan la intensión docente para emprender, a partir de un discurso y formas metodológicas establecidas con esa intención. En segundo lugar, se asume el espacio y tiempo la clase como unidad de análisis, para lograr objetivos de tipo institucional, programático y temático y en la parte final, se examina la evaluación docente y se hacen consideraciones generales para una propuesta de evaluación,  que surge al investigar la actuación del maestro.

  18. High temperature polymer electrolyte membrane fuel cells: Approaches, status, and perspectives

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  19. Mechanical Characterization of Anion Exchange Membranes Under Controlled Environmental Conditions

    Science.gov (United States)

    2015-05-11

    little market penetration has been achieved. Proton exchange membrane fuel cells ( PEMFC ) have struggled primarily due to high cost, driven by the use...and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs , Appl. Catal. B Environ. 56 (2005) 9–35. doi:10.1016/j.apcatb...resins for PEMFCs , Electrochim. Acta. 50 (2004) 571–575. doi:10.1016/j.electacta.2004.01.133. [89] S. Bhadra, N.H. Kim, J.S. Choi, K.Y. Rhee, J.H. Lee

  20. Fuel Cell Stack Testing and Durability in Support of Ion Tiger UAV

    Science.gov (United States)

    2010-06-02

    N00173-08-2-C008 specified. In June 2008, the first M250 stack 242503 data were incorporated into the PEMFC system model as a look-up data table...control and operational model which implements the operational strategy by controlling the power from the PEMFC systems and battery pack for a total...Outputs PEMFC System Outputs <~~>*<*,yrx**i~yc*r»>r-’+**^^ FCS_P«wi_Dwn«l (W) 10 15 20 25 BfOfumon PCM« Cwnind Wi ) 5 10 15

  1. A trigeneration system based on polymer electrolyte fuel cell and desiccant wheel – Part B: Overall system design and energy performance analysis

    International Nuclear Information System (INIS)

    Intini, M.; De Antonellis, S.; Joppolo, C.M.; Casalegno, A.

    2015-01-01

    Highlights: • Seasonal simulation of a trigeneration system for building air-conditioning. • Effects of technical constraints on trigeneration system power consumption. • Optimal PEMFC unit size for maximizing trigeneration primary energy savings. - Abstract: This paper represents the second part of a major work focusing on a trigeneration system integrating a low temperature polymer electrolyte fuel cell (PEMFC) and a desiccant wheel-based air handling unit. Low temperature PEMFC systems have a significant potential in combined heating, cooling and power applications. However cogenerated heat temperature is relatively low (up to 65–70 °C), resulting in low efficiency of the cooling process, and the fuel processor is far from being flexible, hindering the operation of the system at low load conditions. Therefore a trigeneration system based on PEMFC should be carefully designed through accurate simulation tools. In the current paper a detailed analysis of the energy performance of the trigenerative system is provided, taking into account constraints of real applications, such as PEMFC part load behavior, desiccant wheel effectiveness, heat storage losses and air handling unit electrical consumptions. The methodology adopted to model system components is deeply described. Energy simulations are performed on yearly basis with variable building air conditioning loads and climate conditions, in order to investigate the optimal trigenerative unit size. A sensitivity analysis on crucial design parameters is provided. It is shown that constrains of actual applications have relevant effects on system energy consumption, which is significantly far from expected values based on a simplified analysis. Primary energy savings can be positive in winter time if the ratio of PEMFC heating capacity to air conditioning peak heating load is close to 0.15. Instead on yearly basis primary energy savings cannot be achieved with present components performance. Positive savings

  2. Experimental study of two-phase flow in a proton exchange membrane fuel cell in short-term microgravity condition

    International Nuclear Information System (INIS)

    Guo, Hang; Liu, Xuan; Zhao, Jian Fu; Ye, Fang; Ma, Chong Fang

    2014-01-01

    Highlights: • Two-phase flow in PEMFC cathode channels is observed in different gravity environments. • The PEMFC shows different operating behavior in normal and microgravity conditions. • Water tends can be removed in microgravity conditions at high water production regime. • Liquid aggregation occurs in microgravity conditions at low water production regime. • Effect of gravity on performance and two-phase flow at two operating regimes is studied. - Abstract: Water management is important for improving the performance and stability of proton exchange membrane fuel cells (PEMFCs) for space applications. An in situ visual observation was conducted on the gas–liquid two-phase flow in the cathode channels of a PEMFC in short-term microgravity condition. The microgravity environment was supplied by a drop tower. A single serpentine flow channel with a depth of 2 mm and a width of 2 mm was applied as the cathode flow field. A membrane electrode assembly comprising of a Nafion 112 membrane sandwiched between gas diffusion layers was used. The anode and cathode were loaded with 1 mg cm −2 platinum. The PEMFC shows a distinct operating behavior in microgravity because of the effect of gravity on the two-phase flow. At a high water production regime, cell performance is enhanced by 4.6% and the accumulated liquid water in the flow channel tends can be removed in microgravity conditions to alleviate flooding. At a low water production regime, cell performance deteriorates by 6.6% and liquid aggregation occurs in the flow channel because of the coalescence of dispersed water droplets in microgravity conditions, thus squeezing the flow channel. The operating behavior of PEMFC in microgravity conditions is different from that in normal gravity conditions. Further studies are needed on PEMFC operating characteristics and liquid management for space applications

  3. Parameter optimization of thermal-model-oriented control law for PEM fuel cell stack via novel genetic algorithm

    International Nuclear Information System (INIS)

    Li Xi; Deng Zhonghua; Wei Dong; Xu Chunshan; Cao Guangyi

    2011-01-01

    Highlights: →We build up the thermal expressions of PEMFC stack. → The expressions are converted into the affine state space control-oriented model for the VSC strategy. → The NGA is developed to optimize the parameter of thermal-model-oriented control law. → Numerical results demonstrate the effectiveness and rationality of the method proposed. - Abstract: It is critical to understand and manage the thermal effects in optimizing the performance and durability of proton exchange membrane fuel cell (PEMFC) stack. And building up the control-oriented thermal model of PEMFC stack is necessary. The thermal model, a set of differential equations, is established according to the conservation equations of mass and energy, which can be used to reflect truly the actual temperature response of PEMFC stack, however, the expressions of the model are too complicated to be used in the design of control. For this reason, the expressions are converted into the affine state space control-oriented model in detail for the variable structure control (VSC) strategy. Meanwhile, the accurate model must be established for the VSC and the parameters of VSC laws should be optimized. Consequently, a novel genetic algorithm (NGA) is developed to optimize the parameter of thermal-model-oriented control law for PEMFC stack. Finally, numerical test results demonstrate the effectiveness and rationality of the method proposed in this paper. It lays the foundation for the realization of online thermal management of PEMFC stack based on VSC.

  4. An energetic-exergetic analysis of a residential CHP system based on PEM fuel cell

    International Nuclear Information System (INIS)

    Barelli, L.; Bidini, G.; Gallorini, F.; Ottaviano, A.

    2011-01-01

    Highlights: → A zero-dimensional of a micro cogenerative (CHP) energy system based on a Proton Exchange Membrane fuel cell (PEMFC) has been developed. → The electrochemical model has been validated with experimental data. → The performances of this CHP system have been evaluated through a series of simulations. → An energy/exergy analysis of the simulation results has allowed to define the PEMFC optimal operating conditions. → The PEMFC optimal operating conditions detected are: 1 atm, 353.15 K and 100% RH. -- Abstract: The use of fuel cell systems for distributed residential power generation represents an interesting alternative to traditional thermoelectric plants due to their high efficiency and the potential recovering of the heat generated by the internal electrochemical reactions. In this paper the study of a micro cogenerative (CHP) energy system based on a Proton Exchange Membrane fuel cell (PEMFC) is reported. With the aim to evaluate the performance and then the feasibility of this non-conventional energy system, in consideration of thermal and electrical basic demand of a multifamily apartment blocks, a zero-dimensional PEMFC model in Aspen Plus environment has been developed. A simulations sequence has been carried out at different operating conditions of the fuel cell (varying temperature, pressure and relative humidity). Subsequently, on the basis of the obtained results, an energy/exergy analysis has been conducted to define the optimal operating conditions of the PEMFC that ensures the most efficient use of the energy and exergy inputs.

  5. A Review on Cold Start of Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Zhongmin Wan

    2014-05-01

    Full Text Available Successful and rapid startup of proton exchange membrane fuel cells (PEMFCs at subfreezing temperatures (also called cold start is of great importance for their commercialization in automotive and portable devices. In order to maintain good proton conductivity, the water content in the membrane must be kept at a certain level to ensure that the membrane remains fully hydrated. However, the water in the pores of the catalyst layer (CL, gas diffusion layer (GDL and the membrane may freeze once the cell temperature decreases below the freezing point (Tf. Thus, methods which could enable the fuel cell startup without or with slight performance degradation at subfreezing temperature need to be studied. This paper presents an extensive review on cold start of PEMFCs, including the state and phase changes of water in PEMFCs, impacts of water freezing on PEMFCs, numerical and experimental studies on PEMFCs, and cold start strategies. The impacts on each component of the fuel cell are discussed in detail. Related numerical and experimental work is also discussed. It should be mentioned that the cold start strategies, especially the enumerated patents, are of great reference value on the practical cold start process.

  6. High temperature PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianlu; Xie, Zhong; Zhang, Jiujun; Tang, Yanghua; Song, Chaojie; Navessin, Titichai; Shi, Zhiqing; Song, Datong; Wang, Haijiang; Wilkinson, David P.; Liu, Zhong-Sheng; Holdcroft, Steven [Institute for Fuel Cell Innovation, National Research Council Canada, Vancouver, BC (Canada V6T 1W5)

    2006-10-06

    There are several compelling technological and commercial reasons for operating H{sub 2}/air PEM fuel cells at temperatures above 100{sup o}C. Rates of electrochemical kinetics are enhanced, water management and cooling is simplified, useful waste heat can be recovered, and lower quality reformed hydrogen may be used as the fuel. This review paper provides a concise review of high temperature PEM fuel cells (HT-PEMFCs) from the perspective of HT-specific materials, designs, and testing/diagnostics. The review describes the motivation for HT-PEMFC development, the technology gaps, and recent advances. HT-membrane development accounts for {approx}90% of the published research in the field of HT-PEMFCs. Despite this, the status of membrane development for high temperature/low humidity operation is less than satisfactory. A weakness in the development of HT-PEMFC technology is the deficiency in HT-specific fuel cell architectures, test station designs, and testing protocols, and an understanding of the underlying fundamental principles behind these areas. The development of HT-specific PEMFC designs is of key importance that may help mitigate issues of membrane dehydration and MEA degradation. (author)

  7. Novel variable structure control for the temperature of PEM fuel cell stack based on the dynamic thermal affine model

    International Nuclear Information System (INIS)

    Li Xi; Deng Zhonghua; Wei Dong; Xu Chunshan; Cao Guangyi

    2011-01-01

    Highlights: → The affine state space control-oriented model is designed and realized for the variant structure control (VSC) strategy. → The VSC with rapid-smooth reaching law and rapid-convergent sliding mode is presented for the PEMFC stack temperature. → Numerical results show that the method can control the operating temperature to reach the target value satisfactorily. - Abstract: Dynamic thermal management of proton exchange membrane fuel cell stack (PEMFC) is a very important aspect, which plays an important role on electro-reaction. Its variation also has a significant influence on the performance and lifespan of PEMFC stack. The temperature of stack should be controlled efficiently, which has great impacts on the performance of PEMFC due to the thermal variation. Based on the control-oriented dynamic thermal affine model identified by optimization algorithm, a novel variable structures control (VSC) with rapid-smooth reaching law (RSRL) and rapid-convergent sliding mode (FCSM) is presented for the temperature control system of PEMFC stack. Numerical test results show that the method can control the operating temperature to reach the target value satisfactorily, which proves the effectiveness and robustness of the algorithm.

  8. The Use of LMS AMESim in the Fault Diagnosis of a Commercial PEM Fuel Cell System

    Directory of Open Access Journals (Sweden)

    Reem Izzeldin Salim

    2018-01-01

    Full Text Available The world’s pollution rates have been increasing exponentially due to the many reckless lifestyle practices of human beings as well as their choices of contaminating power sources. Eventually, this lead to a worldwide awareness on the risks of those power sources, and in turn, a movement towards the exploration and deployment of several green technologies emerged. Proton Exchange Membrane Fuel cells (PEMFCs are one of those green technologies. However, in order to be able to successfully and efficiently deploy PEMFC systems, a solid fault diagnosis scheme is needed. The development of accurate model based fault diagnosis schemes has been imposing a lot of challenge and difficulty on researchers due to the high complexity of the PEMFC system. Furthermore, confidentiality issues with the manufacturer can also impose further constraints on the model development of a commercial PEMFC system. In this work, an approach to develop an accurate PEMFC system model despite the lack of crucial system information is presented through the use of Siemens LMS AMESim software. The developed model is then used to develop a fault diagnosis scheme that is able to detect and isolate five system faults.

  9. Experimental and numerical studies of micro PEM fuel cell

    Science.gov (United States)

    Peng, Rong-Gui; Chung, Chen-Chung; Chen, Chiun-Hsun

    2011-10-01

    A single micro proton exchange membrane fuel cell (PEMFC) has been produced using Micro-electromechanical systems (MEMS) technology with the active area of 2.5 cm2 and channel depth of about 500 µm. A theoretical analysis is performed in this study for a novel MEMS-based design of amicro PEMFC. Themodel consists of the conservation equations of mass, momentum, species and electric current in a fully integrated finite-volume solver using the CFD-ACE+ commercial code. The polarization curves of simulation are well correlated with experimental data. Three-dimensional simulations are carried out to treat prediction and analysis of micro PEMFC temperature, current density and water distributions in two different fuel flow rates (15 cm3/min and 40 cm3/min). Simulation results show that temperature distribution within the micro PEMFC is affected by water distribution in the membrane and indicate that low and uniform temperature distribution in the membrane at low fuel flow rates leads to increased membrane water distribution and obtains superior micro PEMFC current density distribution under 0.4V operating voltage. Model predictions are well within those known for experimental mechanism phenomena.

  10. Correlating Structure and Oxygen Reduction Activity on Y/Pt(111) and Gd/Pt(111) Single Crystals

    DEFF Research Database (Denmark)

    Ulrikkeholm, Elisabeth Therese; Pedersen, Anders Filsøe; Johansson, Tobias Peter

    2015-01-01

    Polymer Electrolyte Membrane Fuel Cells (PEMFC) hold promise as a zero-emission source of power, particularly suitable for automotive vehicles. However, the high loading of Pt required to catalyse the Oxygen Reduction Reaction (ORR) at the PEMFC cathode prevents the commercialisation of this tech......Polymer Electrolyte Membrane Fuel Cells (PEMFC) hold promise as a zero-emission source of power, particularly suitable for automotive vehicles. However, the high loading of Pt required to catalyse the Oxygen Reduction Reaction (ORR) at the PEMFC cathode prevents the commercialisation...... of this technology. Improving the activity of Pt by alloying it with other metals could decrease the loading of Pt at the cathode to a level comparable to Pt-group metal loading in internal combustion engines. PtxY and PtxGd exhibit exceptionally high activity for oxygen reduction, both in the polycrystalline form...

  11. Study and performances analysis of fuel cell assisted vector control variable speed drive system used for electric vehicles

    Science.gov (United States)

    Pachauri, Rupendra Kumar; Chauhan, Yogesh K.

    2017-02-01

    This paper is a novel attempt to combine two important aspects of fuel cell (FC). First, it presents investigations on FC technology and its applications. A description of FC operating principles is followed by the comparative analysis of the present FC technologies together with the issues concerning various fuels. Second, this paper also proposes a model for the simulation and performances evaluation of a proton exchange membrane fuel cell (PEMFC) generation system. Furthermore, a MATLAB/Simulink-based dynamic model of PEMFC is developed and parameters of FC are so adjusted to emulate a commercially available PEMFC. The system results are obtained for the PEMFC-driven adjusted speed induction motor drive (ASIMD) system, normally used in electric vehicles and analysis is carried out for different operating conditions of FC and ASIMD system. The obtained results prove the validation of system concept and modelling.

  12. Fuel Cells and Other Emerging Manportable Power Technologies for the NATO Warfighter. Part 1: Power Sources for Manportable/Manwearable Applications (Piles a combustible et autres technologies portatives d’alimentation en energie pour les combattants de l’OTAN - Partie 1: Sources d’alimentation pour les applications transportables/portables par l’homme)

    Science.gov (United States)

    2014-10-01

    combinations the open circuit voltage is between 1 and 1.2 V, whereas the on load voltage is typically 0.4 – 0.5 V for DMFC, 0.65 – 0.7 V for PEMFC and...contrast to AFC it was shown the AEM is not irreversibly destroyed by CO2. As with PEMFC , AEMFC also offers the possibility to be directly fuelled with...ppm for the LT PEM FC. For HT PEMFC the catalysts must be resistant to support corrosion (nanoparticles detachment) and to fast degradation processes

  13. Fabrication of a nanosize-Pt-embedded membrane electrode assembly to enhance the utilization of Pt in proton exchange membrane fuel cells.

    Science.gov (United States)

    Choe, Junseok; Kim, Doyoung; Shim, Jinyong; Lee, Inhae; Tak, Yongsug

    2011-08-01

    A procedure to locate the Pt nanostructure inside the hydrophilic channel of a Nafion membrane was developed in order to enhance Pt utilization in PEMFCs. Nanosize Pt-embedded MEA was constructed by Cu electroless plating and subsequent Pt electrodeposition inside the hydrophilic channels of the Nafion membrane. The metallic Pt nanostructure fabricated inside the membrane was employed as an oxygen reduction catalyst for a PEMFC and facilitated effective use of the hydrophilic channels inside the membrane. Compared to the conventional MEA, a Pt-embedded MEA with only 68% Pt loading showed better PEMFC performance.

  14. Modelos para estimar consumo e exigências nutricionais para poedeiras comerciais

    OpenAIRE

    Palma Bendezu, Hilda Cristina [UNESP

    2016-01-01

    O objetivo deste trabalho foi elaborar um modelo para calcular as ingestões de aminoácidos e energia para a fase de maturação sexual e produção de ovos. As exigências de energia, aminoácidos e consumo de ração foram calculados pelo método fatorial, considerando na fase de maturação sexual a quantidade de nutrientes requerida para mantença e a quantidade de nutrientes necessários para crescimento e deposição de nutrientes corporais em cada componente do corpo (ovário, oviduto, corpo livre de ...

  15. Modelos para estimar as exigências de energia metabolizável para poedeiras

    OpenAIRE

    Sakomura,Nilva Kazue; Basaglia,Roberta; Sá-Fortes,Cristina M. L.; Fernandes,João Batista K.

    2005-01-01

    Objetivou-se, com este trabalho, elaborar um modelo para estimar as exigências de energia metabolizável (EM) para poedeiras leves da linhagem Lohmann LSL, utilizando-se o método fatorial. Para determinar o efeito da temperatura sobre as exigências de EM para mantença, foram conduzidos experimentos em câmaras climáticas com temperaturas constantes de 12, 22 e 31ºC, utilizando a técnica do abate comparativo. A exigência de energia líquida para o ganho de peso foi determinada por meio da regress...

  16. Construction and evaluation of a fuel cell prototype (proton exchange fuel cell); Construccion y evaluacion de un prototipo de celda a combustible (proton exchange fuel cell)

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, L. [Laboratorio de Pesquisa em Energia - LAPEN, Universidade do Vale do Itajai, São Jose, SC (Brasil)] e-mail: luciano.silva@univali.br; Paula, M.M.S.; Fiori, M [Lasicom, Universidade do Extremos Sul Catarinense (UNESC), Criciuma, S.C. (Brasil); Benavides, R. [Centro de Investigacion en Quimica Aplicada (CIQA), Saltillo, Coahuila (Mexico); Santos, V. [Laboratorio de Pesquisa em Energia - LAPEN, Universidade do Vale do Itajai, São Jose, SC (Brasil)

    2009-09-15

    Because electric energy is a vitally important material for the development of the country, this work is aimed at offering an alternative methodology for the construction and operational demonstration of a PEMFC fuel cell. Recently discovered natural gas reserves can be exploited using modern methods and its use fulfills generation, distribution and low environmental impact priorities. All these factors can be observed with the use of fuel cells, especially when working with reformed natural gas. In addition to its low environmental impact during the generation of this energy, the use of fuel cells reflects a generator source that can be located with the consumer, further reducing problems created by transmission lines, fuel transport, etc. Fuel cells are receiving a great deal of attention from the international community and some models are already commercially available. They are showing excellent possibilities for becoming one of the future technologies to generate electric energy with low environmental impact. [Spanish] En funcion de la necesidad de energia electrica como insumo de vital importancia para el desarrollo del pais, este trabajo pretende ofrecer una metodologia alternativa para la construccion y demostracion operacional de una celda a combustible del tipo PEMFC. La explotacion de las reservas de gas natural descubiertas recientemente puede realizarse a traves de metodos modernos y su uso tiene las prioridades de generacion, distribucion y bajo impacto ambiental. Todos estos aspectos se pueden observar dentro del uso de celdas a combustible, especialmente cuando se trabaja con gas natural reformado. Ademas del factor de bajo impacto ambiental durante la misma generacion de energia, el uso de las celdas a combustible involucra una fuente generadora, que puede colocarse junto al consumidor, reduciendo aun mas los problemas generados por las lineas de transmision, el transporte del combustible, etc. Las celdas a combustible estan recibiendo una gran

  17. Imade-imide cross-linked PEEK proton exchange membrane.

    CSIR Research Space (South Africa)

    Luo, H

    2009-08-01

    Full Text Available The proton exchange membrane is a key component of polymer electrolyte membrane fuel cell (PEMFC). It plays an important role, conducts protons and separates the fuel from oxidant in PEMFC. DuPont’s Nafion is a perfluorinated sulfonic acid polymer...

  18. SPRING Project on Mechanical Energy on Demand from High Strain Actuators

    Science.gov (United States)

    2009-09-02

    containing N-heterocycles and acidic functional groups Operation of a PEMFC under essentially water-free conditions involves a different mechanism...Temperature-Polymer Electrolyte Membrane-Fuel Cell (HT- PEMFC ) Based on Functionalized Polysiloxanes. Fuel Cells. (2007), 1, 40–6. 14. Woudenberg, R.C

  19. New, efficient and viable system for ethanol fuel utilization on combined electric/internal combustion engine vehicles

    Science.gov (United States)

    Sato, André G.; Silva, Gabriel C. D.; Paganin, Valdecir A.; Biancolli, Ana L. G.; Ticianelli, Edson A.

    2015-10-01

    Although ethanol can be directly employed as fuel on polymer-electrolyte fuel cells (PEMFC), its low oxidation kinetics in the anode and the crossover to the cathode lead to a substantial reduction of energy conversion efficiency. However, when fuel cell driven vehicles are considered, the system may include an on board steam reformer for converting ethanol into hydrogen, but the hydrogen produced contains carbon monoxide, which limits applications in PEMFCs. Here, we present a system consisting of an ethanol dehydrogenation catalytic reactor for producing hydrogen, which is supplied to a PEMFC to generate electricity for electric motors. A liquid by-product effluent from the reactor can be used as fuel for an integrated internal combustion engine, or catalytically recycled to extract more hydrogen molecules. Power densities comparable to those of a PEMFC operating with pure hydrogen are attained by using the hydrogen rich stream produced by the ethanol dehydrogenation reactor.

  20. An assessment of the energetic flows in a commercial PEM fuel-cell system

    International Nuclear Information System (INIS)

    Jovan, Vladimir; Perne, Matija; Petrovcic, Janko

    2010-01-01

    Some primary issues have not yet been fully investigated on the way towards the commercialization of fuel-cell-based systems (FCS), e.g., their actual efficiency, reliability, safety, degradation, maintainability, etc. This article deals with an estimation of the real energetic flows and the corresponding electrical efficiency of a commercial proton-exchange-membrane fuel-cell hydrogen-fed generator set (PEMFCS). The fuel-cell power system considered here is planned to be the source of both electrical and thermal energy in a mobile dwelling container unit with in-built fuel-cell-based cogeneration system, and for the design of a cogeneration unit the actual amount of disposable energy from the PEMFC unit should be estimated. The assessment of the actual energetic flows, the disposable energy and the consequent electrical efficiency of the case-study PEMFCS is carried out using commercial technical data for the PEMFCS.

  1. Leading fuel cell projects ``PEM``; Brennstoffzellen-Leitprojekte ``PEM``

    Energy Technology Data Exchange (ETDEWEB)

    Isenberg, G

    1996-12-31

    Polymer electrolyte diaphragm fuel cells (PEMFC) are distinguished by high specific power densities which are necessary in the field of electrical drives, high efficiencies and no or very low emission of harmful substances, depending on the fuel. In the context of a leading project supported by BMBF, the development of improved and above all, more reasonably priced components for the PEMFC and the reforming of methanol is to work out the important technical basis for the subsequent economic conversion into a vehicle drive. (orig.) [Deutsch] Polymer-Elektrolyt-Membran-Brennstoffzellen (PEMFC) zeichnen sich durch hohe spezifische Leistungsdichten, wie sie im Bereich elektrischer Antriebe notwendig sind, hohe Wirkungsgrade und treibstoffabhaengig keine bzw. sehr niedrige Schadstoffemission aus. Im Rahmen eines BMBF-gefoerderten Leitprojekts sollen mit der Entwicklung verbesserter, vor allem kostenguenstiger Komponenten fuer die PEMFC und die Methanol-Reformierung wesentliche technologische Grundlagen fuer die anschliessende wirtschaftliche Umsetzung als Fahrzeugantrieb erarbeitet werden. (orig.)

  2. Significados da gravidez e da maternidade: discursos de primíparas e multíparas

    OpenAIRE

    Silva, Flavia Baroni; Souza, Laura Vilela e; Scorsolini-Comin, Fabio

    2013-01-01

    Resumo: O objetivo foi compreender os sentidos sobre maternidade e as vivências da gravidez em gestantes primíparas e multíparas. Foram entrevistadas seis gestantes, sendo três primíparas e três multíparas. Nas falas, foram trazidos temas como dificuldades físicas, alterações corporais, repercussão da gravidez no relacionamento conjugal, planejamento da gravidez e envolvimento paterno. Observou-se, nas primíparas, que a inexperiência trouxe insegurança, ao passo que, em algumas multíparas, ho...

  3. Estrategias para negociaciones exitosas.

    OpenAIRE

    José B. Parra V; Evelinda Santiago J.; Misael Murillo M.; Candy Atonal N.

    2010-01-01

    Las estrategias de negociación son herramientas para disminuir conflictos o para intercambiar bienes y servicios. Una negociación exitosa crea relaciones de solidaridad y propicia reciprocidad, cooperación y confianza para quienes tendrán relaciones permanentes de negociación con beneficios para ambas partes. Una estrategia de negociación exitosa requiere manejar el desarrollo del ambiente social del grupo de personas, con la finalidad de tener presente las fronteras que no pueden irrumpirse....

  4. Opportunities for Waste Heat Recovery at Contingency Bases

    Science.gov (United States)

    2016-04-01

    are polymer electrolyte mem- brane fuel cells ( PEMFC ) and solid oxide fuel cells (SOFCs). The biggest drawback to fuel cell CHP systems are their high...Rankine Cycle ORNL Oak Ridge National Laboratory OSHA Occupational Safety and Health Administration PAX Personnel PCM Phase Change Material PEMFC

  5. Probing water structure and transport in proton exchange membranes

    NARCIS (Netherlands)

    Ling, X.

    2018-01-01

    Proton exchange membrane fuel cells (PEMFCs) have attracted tremendous attention as alternative energy sources because of their high energy density and practically zero greenhouse gas emission - water is their only direct by-product. Critical to the function of PEMFCs is fast proton and water

  6. Proton Exchange Membrane Fuel Cells Applied for Transport Sector

    DEFF Research Database (Denmark)

    Hosseinzadeh, Elham; Rokni, Masoud

    2010-01-01

    A thermodynamic analysis of a PEMFC (proton exchange membrane fuel cell) is investigated. PEMFC may be the most promising technology for fuel cell automotive systems, which is operating at quite low temperatures, (between 60 to 80℃). In this study the fuel cell motive power part of a lift truck has...... been investigated. The fuel cell stack used in this model is developed using a Ballard PEMFC [1], so that the equations used in the stack modeling are derived from the experimental data. The stack can produce 3 to 15 kilowatt electricity depending on the number of cells used in the stack. Some...

  7. Final report on LDRD project : elucidating performance of proton-exchange-membrane fuel cells via computational modeling with experimental discovery and validation.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chao Yang (Pennsylvania State University, University Park, PA); Pasaogullari, Ugur (Pennsylvania State University, University Park, PA); Noble, David R.; Siegel, Nathan P.; Hickner, Michael A.; Chen, Ken Shuang

    2006-11-01

    In this report, we document the accomplishments in our Laboratory Directed Research and Development project in which we employed a technical approach of combining experiments with computational modeling and analyses to elucidate the performance of hydrogen-fed proton exchange membrane fuel cells (PEMFCs). In the first part of this report, we document our focused efforts on understanding water transport in and removal from a hydrogen-fed PEMFC. Using a transparent cell, we directly visualized the evolution and growth of liquid-water droplets at the gas diffusion layer (GDL)/gas flow channel (GFC) interface. We further carried out a detailed experimental study to observe, via direct visualization, the formation, growth, and instability of water droplets at the GDL/GFC interface using a specially-designed apparatus, which simulates the cathode operation of a PEMFC. We developed a simplified model, based on our experimental observation and data, for predicting the onset of water-droplet instability at the GDL/GFC interface. Using a state-of-the-art neutron imaging instrument available at NIST (National Institute of Standard and Technology), we probed liquid-water distribution inside an operating PEMFC under a variety of operating conditions and investigated effects of evaporation due to local heating by waste heat on water removal. Moreover, we developed computational models for analyzing the effects of micro-porous layer on net water transport across the membrane and GDL anisotropy on the temperature and water distributions in the cathode of a PEMFC. We further developed a two-phase model based on the multiphase mixture formulation for predicting the liquid saturation, pressure drop, and flow maldistribution across the PEMFC cathode channels. In the second part of this report, we document our efforts on modeling the electrochemical performance of PEMFCs. We developed a constitutive model for predicting proton conductivity in polymer electrolyte membranes and compared

  8. 3-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Fuel Cell Using Different Fuels

    Science.gov (United States)

    2011-01-01

    major types of fuel cells in practice are listed below: Polymer Electrolyte Membrane Fuel Cell ( PEMFC ) Alkaline Fuel cell (AFC) Phosphoric Acid...Material Operating Temperature (oC) Efficiency (%) PEMFC H2, Methanol, Formic Acid Hydrated Organic Polymer < 90 40-50 AFC Pure H2 Aqueous

  9. Neutron Imaging of Lithium Concentration for Validation of Li-Ion Battery State of Charge Estimation

    Science.gov (United States)

    2010-12-01

    2008: Understanding liq- uid water distribution and removal phenomena in an op- erating pemfc via neutron radiography. Journal of The...2008: Measurement of liq- uid water accumulation in a pemfc with dead-ended an- ode. Journal of The Electrochemical Society, 155 (11), B1168–B1178

  10. Low-cost non-fluorinated membranes for fuel cells

    CSIR Research Space (South Africa)

    Luo, H

    2010-08-31

    Full Text Available the driver of the next growth wave of the world’s economy. A proton conductive membrane is the core of the polymer electrolyte membrane fuel cell (PEMFC). Presently, Nafion® membranes are widely used in PEMFC. However, the high cost, low operation temperature...

  11. Analysis for impedance electrochemistry 'on-line' of membrane/electrode assemble (MEA) of protons exchange membrane fuel cells (PEMFC); Analise por impedancia eletroquimica 'on-line' de conjuntos eletrodos/membrana (MEA) de celulas a combustivel a membrana polimetrica (PEMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Antonio Rodolfo dos

    2007-07-01

    This work reports results of studies and characterization on membrane electrode assemblies (MEAs) for proton exchange membrane fuel cell (PEMFC). Some cell operation conditions and different processes of MEA production were investigated. The electrochemical impedance spectroscopy technique (EIS) (in situ - 0 to 16 A) was used 'on-line' as a tool for diagnosis, concerning the cell performance. The EIS measurements were carried out with a FC350 Fuel Cell EIS System (GAMRY), coupled to a PC4 potentiostat/galvanostat and connected to the electronic load (TDI) for 'on-line' EIS experiments (100 mHz - 10 kHz, dU = 5 mV). MEAs with 25 cm{sup 2} surface area, using PtM/C 20% (M Ru, Sn or Ni) electrocatalysts were manufactured using the alcohol reduction process (ARP). The catalytic ink was applied directly into the carbon cloth (GDL) and pressed in the Nafion membrane (105). MEAs using Pt/C and Pt Ru/C 20% from E-TEK electrocatalysts were manufactured by comparison. All the cathodes were sprayed with Pt/C 20% from E-TEK. The noble metal concentrations used were set to 0.4 mg Pt.cm{sup -2} at the anode and 0.6 mg Pt.cm{sup -2} at the cathode (E-TEK). Nyquist diagrams of the MEAs with Pt/C and PtRu/C from E-TEK or PtM/C (M = Ru, Sn or Ni) ARP showed essentially the same ohmic resistances for the MEAs. This fact can be explained by suppression of agglomerates during the MEA preparation process or by the homogeneity of the anchored electrocatalysts at the carbon surface. It could also be observed, at low current densities, that there was a significant performance difference between the electrocatalysts from E-TEK and those prepared with the alcohol reduction process. The polarization curves results confirmed that the Pt M/C (M = Ru, Sn or Ni) ARP showed an activity increase for the methanol and ethanol fed cells. The technique of EIE was shown efficient for the evaluation of the method preparation of MEAs and the acting of the cell, the results of EIE

  12. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    International Nuclear Information System (INIS)

    Hitchcock, A. P.; Lee, V.; Wu, J.; Cooper, G.; West, M. M.; Berejnov, V.; Soboleva, T.; Susac, D.; Stumper, J.

    2016-01-01

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined

  13. Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, A. P., E-mail: aph@mcmaster.ca; Lee, V.; Wu, J.; Cooper, G. [Chemistry & Chemical Biology, McMaster University, Hamilton, ON, L8S 4M1 (Canada); West, M. M.; Berejnov, V. [Faculty of Health Sciences Electron Microscopy, McMaster University, Hamilton, ON L8N 3Z5 (Canada); Soboleva, T.; Susac, D.; Stumper, J. [Automotive Fuel Cell Cooperation Corp., Burnaby BC V5J 5J8 (Canada)

    2016-01-28

    Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.

  14. Design of flow-field patterns for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Rosli, M.I.; Wan Ramli Wan Daud; Kamaruzzaman Sopian; Jaafar Sahari

    2006-01-01

    Fuel cells are electrochemical devices that produce electricity at high efficiency without combustion. Fuel cells are emerging as viable candidates as power sources in many applications, including road vehicles, small-scale power stations, and possibly even portable electronics. This paper addresses the design of flow-field patterns for proton exchange membrane fuel cell (PEMFC). The PEMFC is a low-temperature fuel cell, in which a proton conductive polymer membrane is used as the electrolyte. In PEMFC, flow-field pattern is one important thing that effects the performance of PEMFC. This paper present three types of flow-field pattern that will be consider to be testing using CFD analysis and by experimental. The design look detail on to their shape and dimension to get the best pattern in term of more active electrode area compare to electrode area that will be used. Another advantage and disadvantage for these three type of flow-field patterns from literature also compared in this paper

  15. Nanostructure-based proton exchange membrane for fuel cell applications at high temperature.

    Science.gov (United States)

    Li, Junsheng; Wang, Zhengbang; Li, Junrui; Pan, Mu; Tang, Haolin

    2014-02-01

    As a clean and highly efficient energy source, the proton exchange membrane fuel cell (PEMFC) has been considered an ideal alternative to traditional fossil energy sources. Great efforts have been devoted to realizing the commercialization of the PEMFC in the past decade. To eliminate some technical problems that are associated with the low-temperature operation (such as catalyst poisoning and poor water management), PEMFCs are usually operated at elevated temperatures (e.g., > 100 degrees C). However, traditional proton exchange membrane (PEM) shows poor performance at elevated temperature. To achieve a high-performance PEM for high temperature fuel cell applications, novel PEMs, which are based on nanostructures, have been developed recently. In this review, we discuss and summarize the methods for fabricating the nanostructure-based PEMs for PEMFC operated at elevated temperatures and the high temperature performance of these PEMs. We also give an outlook on the rational design and development of the nanostructure-based PEMs.

  16. Nanotechnology for environmentally sustainable electromobility

    Science.gov (United States)

    Ellingsen, Linda Ager-Wick; Hung, Christine Roxanne; Majeau-Bettez, Guillaume; Singh, Bhawna; Chen, Zhongwei; Whittingham, M. Stanley; Strømman, Anders Hammer

    2016-12-01

    Electric vehicles (EVs) powered by lithium-ion batteries (LIBs) or proton exchange membrane hydrogen fuel cells (PEMFCs) offer important potential climate change mitigation effects when combined with clean energy sources. The development of novel nanomaterials may bring about the next wave of technical improvements for LIBs and PEMFCs. If the next generation of EVs is to lead to not only reduced emissions during use but also environmentally sustainable production chains, the research on nanomaterials for LIBs and PEMFCs should be guided by a life-cycle perspective. In this Analysis, we describe an environmental life-cycle screening framework tailored to assess nanomaterials for electromobility. By applying this framework, we offer an early evaluation of the most promising nanomaterials for LIBs and PEMFCs and their potential contributions to the environmental sustainability of EV life cycles. Potential environmental trade-offs and gaps in nanomaterials research are identified to provide guidance for future nanomaterial developments for electromobility.

  17. Design and implementation of fixed-order robust controllers for a proton exchange membrane fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fu-Cheng; Chen, Hsuan-Tsung [Department of Mechanical Engineering, National Taiwan University, No.1, Sec. 4, Roosevelt Road, 10617 Taipei (China)

    2009-03-15

    This paper applies fixed-order multivariable robust control strategies to a proton exchange membrane fuel cell (PEMFC) system, and implements the designed controllers on a microchip for system miniaturization. In previous studies, robust control was applied to guarantee system stability and to reduce hydrogen consumption for a PEMFC system. It was noted that for standard robust control design, the order of resulting H{sub {infinity}} controllers is dictated by the plants and weighting functions. However, for hardware implementation, controllers with lower orders are preferable in terms of computing efforts and cost. Therefore, in this paper the PEMFC is modeled as multivariable transfer matrices, then three fixed-order robust control algorithms are applied to design controllers with specified orders for a PEMFC. Finally, the designed controllers are implemented on a microchip to regulate the air and hydrogen flow rates. From the experimental results, fixed-order robust control is deemed effective in supplying steady power and reducing fuel consumption. (author)

  18. High performance and durability of order-structured cathode catalyst layer based on TiO_2@PANI core-shell nanowire arrays

    International Nuclear Information System (INIS)

    Chen, Ming; Wang, Meng; Yang, Zhaoyi; Wang, Xindong

    2017-01-01

    Highlights: • TiO_2@PANI core-shell nanowire arrays were prepared and applied as catalyst support. • As-prepared Pt-TiO_2@PANI core-shell nanowire arrays were applied as order-structured cathode catalyst layer. • The novel cathode catalyst structure without Nafion"® ionomer enhance the performance and durability of PEMFC. - Abstract: In this paper, an order-structured cathode catalyst layer consisting of Pt-TiO_2@PANI core-shell nanowire arrays that in situ grown on commercial gas diffusion layer (GDL) are prepared and applied to membrane electrode assembly (MEA) of proton exchange membrane fuel cell (PEMFC). In order to prepare the TiO_2@PANI core-shell nanowire arrays with suitable porosity and prominent conductivity, the morphologies of the TiO_2 nanoarray and electrochemical polymerization process of aniline are schematically investigated. The MEA with order-structured cathode catalyst layer is assembled in the single cell to evaluate the electrochemical performance and durability of PEMFC. As a result, the PEMFC with order-structured cathode catalyst layer shows higher peak power density (773.54 mW cm"−"2) than conventional PEMFC (699.30 mW cm"−"2). Electrochemically active surface area (ECSA) and charge transfer impedance (R_c_t) are measured before and after accelerated degradation test (ADT), and the corresponding experimental results indicate the novel cathode structure exhibits a better stability with respect to conventional cathode. The enhanced electrochemical performance and durability toward PEMFC can be ascribed to the order-structured cathode nanoarray structure with high specific surface area increases the utilization of catalyst and reduces the tortuosity of transport pathways, and the synergistic effect between TiO_2@PANI support and Pt nanoparticles promotes the high efficiency of electrochemical reaction and improves the stability of catalyst. This research provides a facile and controllable method to prepare order

  19. High performance and durability of order-structured cathode catalyst layer based on TiO{sub 2}@PANI core-shell nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ming; Wang, Meng; Yang, Zhaoyi [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); Wang, Xindong, E-mail: echem@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China); School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083 (China)

    2017-06-01

    Highlights: • TiO{sub 2}@PANI core-shell nanowire arrays were prepared and applied as catalyst support. • As-prepared Pt-TiO{sub 2}@PANI core-shell nanowire arrays were applied as order-structured cathode catalyst layer. • The novel cathode catalyst structure without Nafion{sup ®} ionomer enhance the performance and durability of PEMFC. - Abstract: In this paper, an order-structured cathode catalyst layer consisting of Pt-TiO{sub 2}@PANI core-shell nanowire arrays that in situ grown on commercial gas diffusion layer (GDL) are prepared and applied to membrane electrode assembly (MEA) of proton exchange membrane fuel cell (PEMFC). In order to prepare the TiO{sub 2}@PANI core-shell nanowire arrays with suitable porosity and prominent conductivity, the morphologies of the TiO{sub 2} nanoarray and electrochemical polymerization process of aniline are schematically investigated. The MEA with order-structured cathode catalyst layer is assembled in the single cell to evaluate the electrochemical performance and durability of PEMFC. As a result, the PEMFC with order-structured cathode catalyst layer shows higher peak power density (773.54 mW cm{sup −2}) than conventional PEMFC (699.30 mW cm{sup −2}). Electrochemically active surface area (ECSA) and charge transfer impedance (R{sub ct}) are measured before and after accelerated degradation test (ADT), and the corresponding experimental results indicate the novel cathode structure exhibits a better stability with respect to conventional cathode. The enhanced electrochemical performance and durability toward PEMFC can be ascribed to the order-structured cathode nanoarray structure with high specific surface area increases the utilization of catalyst and reduces the tortuosity of transport pathways, and the synergistic effect between TiO{sub 2}@PANI support and Pt nanoparticles promotes the high efficiency of electrochemical reaction and improves the stability of catalyst. This research provides a facile and

  20. Parametric analysis of an irreversible proton exchange membrane fuel cell/absorption refrigerator hybrid system

    International Nuclear Information System (INIS)

    Yang, Puqing; Zhang, Houcheng

    2015-01-01

    A hybrid system mainly consisting of a PEMFC (proton exchange membrane fuel cell) and an absorption refrigerator is proposed, where the PEMFC directly converts the chemical energy contained in the hydrogen into electrical and thermal energies, and the thermal energy is transferred to drive the bottoming absorption refrigerator for cooling purpose. By considering the existing irreversible losses in the hybrid system, the operating current density region of the PEMFC permits the absorption refrigerator to exert its function is determined and the analytical expressions for the equivalent power output and efficiency of the hybrid system under different operating conditions are specified. Numerical calculations show that the equivalent maximum power density and the corresponding efficiency of the hybrid system can be respectively increased by 5.3% and 6.8% compared to that of the stand-alone PEMFC. Comprehensive parametric analyses are conducted to reveal the effects of the internal irreversibility of the absorption refrigerator, operating current density, operating temperature and operating pressure of the PEMFC, and some integrated parameters related to the thermodynamic losses on the performance of the hybrid system. The model presented in the paper is more general than previous study, and the results for some special cases can be directly derived from this paper. - Highlights: • A CHP system composed of a PEMFC and an absorption refrigerator is proposed. • Current density region enables the absorption refrigerator to work is determined. • Multiple irreversible losses in the system are analytically characterized. • Maximum power density and corresponding efficiency can be increased by 5.3% and 6.8%. • Effects of some designing and operating parameters on the performance are discussed

  1. Performance evaluation of an air-breathing high-temperature proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Wu, Qixing; Li, Haiyang; Yuan, Wenxiang; Luo, Zhongkuan; Wang, Fang; Sun, Hongyuan; Zhao, Xuxin; Fu, Huide

    2015-01-01

    Highlights: • An air-breathing HT-PEMFC was designed and evaluated experimentally. • The peak power density of the air-breathing HT-PEMFC was 220.5 mW cm"−"2 at 200 °C. • Break-in behavior and effects of temperature and anodic stoichiometry were studied. • The effect of cell orientations on the performance was investigated. • The degradation rate of the air-breathing HT-PEMFC was around 58.32 μV h"−"1. - Abstract: The air-breathing proton exchange membrane fuel cell (PEMFC) is of great interest in mobile power sources because of its simple system design and low parasitic power consumption. Different from previous low-temperature air-breathing PEMFCs, a high-temperature PEMFC with a phosphoric acid doped polybenzimidazole (PBI) membrane as the polymer electrolyte is designed and investigated under air-breathing conditions. The preliminary results show that a peak power density of 220.5 mW cm"−"2 at 200 °C can be achieved without employing any water managements, which is comparable to those with conventional Nafion® membranes operated at low temperatures. In addition, it is found that with the present cell design, the limiting current density arising from the oxygen transfer limitation is around 700 mA cm"−"2 even at 200 °C. The short-term durability test at 200 mA cm"−"2 and 180 °C reveals that all the cells exhibit a gradual decrease in the voltage along with a rise in the internal resistance. The degradation rate of continuous operation is around 58.32 μV h"−"1, which is much smaller than those of start/stop cycling operations.

  2. Mathematical modeling of water mass balance for proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Wan Ramli Wan Daud; Kamaruzzaman Sopian; Jaafar Sahari; Nik Suhaimi Mat Hassan

    2006-01-01

    Gas and water management are key to achieving good performance from a proton exchange membrane fuel cell (PEMFC) stack. Water plays a critical role in PEMFC. The proton conductivity is increase with the water content. In order to achieve enough hydration, water is normally introduced into the cell externally by a variety of methods such as liquid injection, steam introduction, and humidification of reactants by passing them through humidifiers before entering the cell. In this paper, mathematical modeling of water mass balance for PEMFC at anode and cathode side are proposed by using external humidification and assume that steady state, constant pressure, constant temperature and gases distribution are uniform

  3. Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell.

    Science.gov (United States)

    Lu, Hui; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2011-10-28

    The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H(2) streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating. This journal is © the Owner Societies 2011

  4. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf

    The strategic developments of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer and afterburner, that are compatible with the HT-PEMFC; and (3......) integration of the HT-PEMFC stack with these compatible subunits. The main goal of the project is a 2kWel HT-PEMFC stack operating in a temperature range of 150-200°C, with a single cell performance target of 0.7 A/cm² at a cell voltage around 0.6 V. The target durability is more than 5,000 hours...

  5. Para-equilibrium phase diagrams

    International Nuclear Information System (INIS)

    Pelton, Arthur D.; Koukkari, Pertti; Pajarre, Risto; Eriksson, Gunnar

    2014-01-01

    Highlights: • A rapidly cooled system may attain a state of para-equilibrium. • In this state rapidly diffusing elements reach equilibrium but others are immobile. • Application of the Phase Rule to para-equilibrium phase diagrams is discussed. • A general algorithm to calculate para-equilibrium phase diagrams is described. - Abstract: If an initially homogeneous system at high temperature is rapidly cooled, a temporary para-equilibrium state may result in which rapidly diffusing elements have reached equilibrium but more slowly diffusing elements have remained essentially immobile. The best known example occurs when homogeneous austenite is quenched. A para-equilibrium phase assemblage may be calculated thermodynamically by Gibbs free energy minimization under the constraint that the ratios of the slowly diffusing elements are the same in all phases. Several examples of calculated para-equilibrium phase diagram sections are presented and the application of the Phase Rule is discussed. Although the rules governing the geometry of these diagrams may appear at first to be somewhat different from those for full equilibrium phase diagrams, it is shown that in fact they obey exactly the same rules with the following provision. Since the molar ratios of non-diffusing elements are the same in all phases at para-equilibrium, these ratios act, as far as the geometry of the diagram is concerned, like “potential” variables (such as T, pressure or chemical potentials) rather than like “normal” composition variables which need not be the same in all phases. A general algorithm to calculate para-equilibrium phase diagrams is presented. In the limit, if a para-equilibrium calculation is performed under the constraint that no elements diffuse, then the resultant phase diagram shows the single phase with the minimum Gibbs free energy at any point on the diagram; such calculations are of interest in physical vapor deposition when deposition is so rapid that phase

  6. Model-based fault detection for proton exchange membrane fuel cell ...

    African Journals Online (AJOL)

    In this paper, an intelligent model-based fault detection (FD) is developed for proton exchange membrane fuel cell (PEMFC) dynamic systems using an independent radial basis function (RBF) networks. The novelty is that this RBF networks is used to model the PEMFC dynamic systems and residuals are generated based ...

  7. Investigation of heating and cooling in a stand-alone high temperature PEM fuel cell system

    International Nuclear Information System (INIS)

    Zhang, Caizhi; Yu, Tao; Yi, Jun; Liu, Zhitao; Raj, Kamal Abdul Rasheedj; Xia, Lingchao; Tu, Zhengkai; Chan, Siew Hwa

    2016-01-01

    Highlights: • Heating-up and cooling-down processes of HT-PEMFC are the mainly interested topics. • Dynamic behaviours, power and energy demand of the heating and cooling was studied. • Hybrid system based on LiFeYPO_4 battery for heating and cooling is built and tested. • The concept of combining different heating sources together is recommended. - Abstract: One key issue pertaining to the cold-start of High temperature PEM fuel cell (HT-PEMFC) is the requirement of high amount of thermal energy for heating up the stack to a temperature of 120 °C or above before it can generate electricity. Furthermore, cooling down the stack to a certain temperature (e.g. 50 °C) is necessary before stopping. In this study, the dynamic behaviours, power and energy demand of a 6 kW liquid cooled HT-PEMFC stack during heating-up, operation and cooling-down were investigated experimentally. The dynamic behaviours of fuel cell under heating-up and cooling-down processes are the mainly interested topics. Then a hybridisation of HT-PEMFC with Li-ion battery to demonstrate the synergistic effect on dynamic behaviour was conducted and validated for its feasibility. At last, the concept of combining different heating sources together is analysed to reduce the heating time of the HT-PEMFC as well.

  8. Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad.

    OpenAIRE

    Reina de los Ángeles Carballé Piñón

    2015-01-01

    Este trabajo "Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad" resulta de la investigación realizada para tesis de maestría; se realizó el estudio de 2 entidades, nos permitió conocer las principales posiciones que sobre motivación existen, factores que la influencian, cómo incide en el desempeño laboral y que acciones diseñar para elevarla. Las 2 entidades seleccionadas, claves en el desempeño empresarial son un centro de interfase y un...

  9. Estrategias para negociaciones exitosas.

    Directory of Open Access Journals (Sweden)

    José B. Parra V

    2010-01-01

    Full Text Available Las estrategias de negociación son herramientas para disminuir conflictos o para intercambiar bienes y servicios. Una negociación exitosa crea relaciones de solidaridad y propicia reciprocidad, cooperación y confianza para quienes tendrán relaciones permanentes de negociación con beneficios para ambas partes. Una estrategia de negociación exitosa requiere manejar el desarrollo del ambiente social del grupo de personas, con la finalidad de tener presente las fronteras que no pueden irrumpirse. Otro aspecto importante, es el lenguaje corporal utilizado por las personas y las tácticas que se practican. El manejo de esta información permite diseñar diferentes modelos de negociaciones para cada caso específico. Este documento propone la utilización de la herramienta MONACO, diseñada por los autores, que es un software útil para encontrar los mejores tácticas posibles dentro de una negociación; basándose en el lenguaje corporal que muestra el negociante oponente durante cada oferta monetaria. El uso de este software da al negociador la oportunidad de manejar las negociaciones con mayor control, el negociador que usa el software puede elegir una estrategia de acuerdo a las relaciones que espera mantener con el negociador oponente.

  10. Electricity generation using vegetal oils: the implantation model for the isolated communities in the Amazon Region; Geracao de eletricidade a partir de oleos vegetais: um modelo de implantacao para comunidades isoladas amazonicas

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Suani Teixeira; Silva, Orlando Cristiano; Velazquez, Silvia M.S.G.; Monteiro, Maria Beatriz C.A.; Silotto, Carlos Eduardo G [Centro Nacional de Referencia em Biomassa - CENBIO, Sao Paulo, SP (Brazil)

    2004-07-01

    The territorial occupation from the Amazon region is characterized by isolated communities, which makes the conventional electric distribution economically and technically impracticable. To solve the electric problem of these communities, it is necessary for them to produce their own fuel in order to generate electric energy and promote the development. These are the premises that have guided the elaboration of the project PROVEGAM - which has as objective, the installation and performance testing of a conventional diesel engine, adapted to operate with palm oil 'in natura' at the community of Vila Soledade, city of Moju, Para State. Vila Soledade is an isolated community that has, approximately, 700 inhabitants. The PROVEGAM project installed a diesel generator adapted with a conversion kit to operate with 'in natura' palm oil. The operation begins and finishes with diesel oil, in order to heat the palm oil and cleaning possible residues. During the diesel generator installation, diesel oil emissions and performance were compared with the palm oil. Analysing the results, this electric model of generating energy is already recommended to be implemented in others Amazon region communities. (author)

  11. Feasibility of Renewable Energy Technology at the Afghanistan National Security University: A Site-Specific Study Focused on Potential Renewable Energy Technologies in Northwest Kabul, Afghanistan

    Science.gov (United States)

    2011-04-26

    70% H2, O2 Proton exchange membrane fuel cell ( PEMFC ) Proton exchange membrane Rm temp to 80 °C 40–60% H2, O2, Air Direct methanol fuel cell...Cell PEMFC Proton Exchange Membrane Fuel Cell PV Photovoltaic SHGC Solar Heat Gain Coefficient SIR savings to investment ratio SOFC Solid Oxide

  12. ¿Argumentar para definir o definir para argumentar?

    OpenAIRE

    Silva, Luz; Samper, Carmen

    2013-01-01

    Se presenta y se ilustra un marco de referencia de un estudio en curso para obtener el título de Maestría en Docencia de la Matemática de la Universidad Pedagógica Nacional (Colombia); estudio sobre la conexión entre las acciones de definir y argumentar, que puede contribuir a la práctica de profesores en ejercicio y en formación. La habilidad para construir una definición es un posible indicio de comprensión, mientras que saberla de memoria no garantiza la comprensión del concepto (Vinner, 1...

  13. Mesostructured platinum-free anode and carbon-free cathode catalysts for durable proton exchange membrane fuel cells.

    Science.gov (United States)

    Cui, Xiangzhi; Shi, Jianlin; Wang, Yongxia; Chen, Yu; Zhang, Lingxia; Hua, Zile

    2014-01-01

    As one of the most important clean energy sources, proton exchange membrane fuel cells (PEMFCs) have been a topic of extensive research focus for decades. Unfortunately, several critical technique obstacles, such as the high cost of platinum electrode catalysts, performance degradation due to the CO poisoning of the platinum anode, and carbon corrosion by oxygen in the cathode, have greatly impeded its commercial development. A prototype of a single PEMFC catalyzed by a mesostructured platinum-free WO3/C anode and a mesostructured carbon-free Pt/WC cathode catalysts is reported herein. The prototype cell exhibited 93% power output of a standard PEMFC using commercial Pt/C catalysts at 50 and 70 °C, and more importantly, CO poisoning-free and carbon corrosion-resistant characters of the anode and cathode, respectively. Consequently, the prototype cell demonstrated considerably enhanced cell operation durability. The mesostructured electrode catalysts are therefore highly promising in the future development and application of PEMFCs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Development of proton exchange membranes fuel cells with sulfonated HTPB-phenol; Desenvolvimento de membranas polimericas trocadoras de protons utilizando PBLH-fenol

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, Fernando A.; Oliveira, Angelo R.S.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Lab. de Polimeros Sinteticos], e-mail: ferraz@quimica.ufpr.br; Cantao, Mauricio P. [LACTEC - Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil). Centro Politecnico

    2007-07-01

    Proton exchange membrane fuel cells (PEMFC) have been paid attention as promising candidates for vehicle and portable applications. PEMFC employ proton exchange polymer membrane which serves as an electrolyte between anode and cathode. Nafion{sup R} (DuPont), perfluorosulfonic acid/PTFE copolymer membranes are typically used as the polymer electrolyte in PEMFC due to their good chemical and mechanical properties as well as high proton conductivity. However, high cost of these materials is one of main obstacles for commercialization of PEMFC. Extensive efforts have been devoted to develop alternative polymer electrolyte membranes. Our group have investigated the development of proton exchange membranes fuel cells using sulfonated HTPB-Phenyl ether (HTPB-Phenol), making possible the formation of membranes with sulfonated groups amount of 2,4, 2,5 and 2,8 mmol/g of dry polymer from HTPB-Phenol 80, 98 and 117 respectively. These results mean a bigger values than those of the Nafion{sup R} membranes, that possess an ion exchange capacity of 0,67 up to 1,25 mmol/g of sulfonated groups. (author)

  15. Metallofullerenes as fuel cell electrocatalysts: a theoretical investigation of adsorbates on C59Pt.

    Science.gov (United States)

    Gabriel, Margaret A; Genovese, Luigi; Krosnicki, Guillaume; Lemaire, Olivier; Deutsch, Thierry; Franco, Alejandro A

    2010-08-28

    Nano-structured electrode degradation in state-of-the-art polymer electrolyte membrane fuel cells (PEMFCs) is one of the main shortcomings that limit the large-scale development and commercialization of this technology. During normal operating conditions of the fuel cell, the PEMFC lifetime tends to be limited by coarsening of the cathode's Pt-based catalyst and by corrosion of the cathode's carbon black support. Because of their chemical properties, metallofullerenes such as C(59)Pt may be more electrochemically stable than the Pt/C mixture. In this paper we investigate, by theoretical methods, the stability of oxygen reduction reaction (ORR) adsorbates on the metallofullerene C(59)Pt and evaluate its potential as a PEMFC fuel cell catalyst.

  16. Guias ópticos para sensores

    OpenAIRE

    Marcos de Castro Pacitti

    1993-01-01

    Neste trabalho foram estudados guias ópticos para atuarem como sensores ou em sistemas sensores. Ênfase especial foi dada em guias ópticos retangulares, para dispositivos ópticos integrados, e fibras ópticas elípticas. A analise de fibras ópticas elípticas resultou em um modelamento pratico para projeto das mesmas em aplicações onde se deseja operar com dois modos guiados, situação esta que se mostra muito atraente para implementação de diversos tipos de sensores a fibra óptica. A seguir es...

  17. Neutron Imaging of Lithium Concentration in Battery Pouch Cells

    Science.gov (United States)

    2011-06-01

    water distribution and removal phenomena in an operating pemfc via neutron radiography,” J. Electrochem. Soc., vol. 155, no. 3, pp. B294–B302, 2008...12] J. B. Siegel, D. A. McKay, A. G. Stefanopoulou, D. S. Hussey, and D. L. Jacobson, “Measurement of liquid water accumulation in a pemfc with dead

  18. Rapid prototyping methods for the manufacture of fuel cells

    Directory of Open Access Journals (Sweden)

    Dudek Piotr

    2016-01-01

    The potential for the application of this method for the manufacture of metallic bipolar plates (BPP for use in proton exchange membrane fuel cells (PEMFCs is presented and discussed. Special attention is paid to the fabrication of light elements for the construction of PEMFC stacks designed for mobile applications such as aviation technology and unmanned aerial vehicles (UAVs.

  19. Composite polymer membranes for proton exchange membrane fuel cells operating at elevated temperatures and reduced humidities

    Science.gov (United States)

    Zhang, Tao

    Proton Exchange Membrane Fuel Cells (PEMFCs) are the leading candidate in the fuel cell technology due to the high power density, solid electrolyte, and low operational temperature. However, PEMFCs operating in the normal temperature range (60-80°C) face problems including poor carbon monoxide tolerance and heat rejection. The poisoning effect can be significantly relieved by operating the fuel cell at elevated temperature, which also improves the heat rejection and electrochemical kinetics. Low relative humidity (RH) operation is also desirable to simplify the reactant humidification system. However, at elevated temperatures, reduced RH PEMFC performance is seriously impaired due to irreversible water loss from presently employed state-of-the-art polymer membrane, Nafion. This thesis focuses on developing polymer electrolyte membranes with high water retention ability for operation in elevated temperature (110-150°C), reduced humidity (˜50%RH) PEMFCs. One approach is to alter Nafion by adding inorganic particles such as TiO2, SiO2, Zr(HPO 4)2, etc. While the presence of these materials in Nafion has proven beneficial, a reduction or no improvement in the PEMFC performance of Nafion/TiO2 and Nafion/Zr(HPO4)2 membranes is observed with reduced particle sizes or increased particle loadings in Nafion. It is concluded that the PEMFC performance enhancement associated with addition of these inorganic particles was not due to the particle hydrophilicity. Rather, the particle, partially located in the hydrophobic region of the membrane, benefits the cell performance by altering the membrane structure. Water transport properties of some Nafion composite membranes were investigated by NMR methods including pulsed field gradient spin echo diffusion, spin-lattice relaxation, and spectral measurements. Compared to unmodified Nafion, composite membranes materials exhibit longer longitudinal relaxation time constant T1. In addition to the Nafion material, sulfonated styrene

  20. Labbtex: Toolbox para generación de informes en LATEX para Matlab

    Directory of Open Access Journals (Sweden)

    José Luis Almazán Gárate

    2012-10-01

    Full Text Available En este artículo se presenta el software desarrollado por el Equipo H3lite dentro del Departamento de Ingeneniería Civil. Transportes de la Escuela de Ingenieros de Caminos, Canales y Puertos de la Universidad Politécnica de Madrid para la generación de informes enLATEX mediante el software Matlab® y la integración en sus rutinas, Labbtex.La librería Labbtex proporciona un marco flexible para mezclar texto y código Matlab® para la generación automática de documentos. Un rchivo fuente simple contiene el texto de documentación y el código Matlab, al correr la aplicación se genera un documento final LATEX que contiene el texto, gráficos y tablas indicados con el formato de un documento LATEX. El código Matlab genera un documento LATEX usando la sintaxis. Así, LATEX (para composición de texto de alta calidad y Matlab® (para cálculo matemático pueden usarse simultáneamente. Esto permite la generación de informes en tiempo real con un uso de recursos mínimo.

  1. Internet como instrumento para la Yihad

    Directory of Open Access Journals (Sweden)

    Alfonso Merlos García

    2006-01-01

    Full Text Available Las extraordinarias ventajas que ofrece Internet lo han convertido en un instrumento clave y dinámico en la estrategia de los yihadistas. Los medios de comunicación, la clase política y las agencias de seguridad e información han tendido a concentrar sus esfuerzos en la neutralización del ciberterrorismo sin prestar suficiente atención a los múltiples usos de Internet que están haciendo los neosalafistas: para la propaganda y para la guerra psicológica, para el reclutamiento y para la financiación, para la documentación y para la planificación de atentados. Las democracias deberían considerar el coste que tendrá la derrota frente al movimiento yihadista globalizado en la batalla por el ciberespacio

  2. Electricity generation using vegetal oils: the implantation model for the isolated communities in the Amazon Region; Geracao de eletricidade a partir de oleos vegetais: um modelo de implantacao para comunidades isoladas amazonicas

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Suani Teixeira; Silva, Orlando Cristiano; Velazquez, Silvia M.S.G.; Monteiro, Maria Beatriz C.A.; Silotto, Carlos Eduardo G. [Centro Nacional de Referencia em Biomassa - CENBIO, Sao Paulo, SP (Brazil)

    2004-07-01

    The territorial occupation from the Amazon region is characterized by isolated communities, which makes the conventional electric distribution economically and technically impracticable. To solve the electric problem of these communities, it is necessary for them to produce their own fuel in order to generate electric energy and promote the development. These are the premises that have guided the elaboration of the project PROVEGAM - which has as objective, the installation and performance testing of a conventional diesel engine, adapted to operate with palm oil 'in natura' at the community of Vila Soledade, city of Moju, Para State. Vila Soledade is an isolated community that has, approximately, 700 inhabitants. The PROVEGAM project installed a diesel generator adapted with a conversion kit to operate with 'in natura' palm oil. The operation begins and finishes with diesel oil, in order to heat the palm oil and cleaning possible residues. During the diesel generator installation, diesel oil emissions and performance were compared with the palm oil. Analysing the results, this electric model of generating energy is already recommended to be implemented in others Amazon region communities. (author)

  3. Cross-elicitation responses to 2-methoxymethyl-para-phenylenediamine in para-phenylenediamine-allergic individuals

    NARCIS (Netherlands)

    Schuttelaar, M.-L.; Coenraads, P.-J.; Blömeke, B.; Goebel, C.

    2016-01-01

    The introduction of a methoxymethyl side chain into para-phenylenediamine (PPD) resulted in the development of a new hair dye molecule: 2-methoxymethyl-para-phenylenediamine (Me-PPD). Besides having excellent hair colouring properties, this PPD derivate has significantly lower skin-sensitizing

  4. Oro para Colombia

    OpenAIRE

    Rubio Forero, María Claudia

    2016-01-01

    Las mujeres han debido atravesar un largo camino partiendo de la discriminación hasta empezar un proceso de equidad en la sociedad y en el deporte, de esta manera llegar a ser parte de un evento como los Juegos Olímpicos. Esta tesis toma el caso de tres atletas colombianas y describe su proceso de formación para lograr dos medallas de oro para el país.

  5. Infraestructura para laboratorios de acceso remoto

    Directory of Open Access Journals (Sweden)

    López Luro, Francisco

    2009-01-01

    Full Text Available Las tecnologías de Internet permiten el uso de sistemas de software distribuido para el acceso en forma remota a laboratorios físicos y virtuales, para llevar a cabo actividades de investigación experimental a distancia. A partir de los marcos teóricos que definen los estructurantes de los laboratorios, los implementadores de laboratorios de acceso remoto deben diseñar y desarrollar arquitecturas de servicios que permitan un acceso flexible y controlado. Este trabajo define una infraestructura para la implementación de aplicaciones para el acceso remoto a laboratorios físicos y virtuales y para la gestión de los mismos. Se presentan conceptos que permiten extender la modalidad tradicional de conexión con un dispositivo, para llevar adelante actividades prácticas de laboratorio colaborativas y concurrentes.

  6. Analysis of the potential use of palm oil biodiesel for power generation in Amazonian remote systems; Analise do potencial do biodiesel de dende para geracao eletrica em sistemas isolados da Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Anamelia Medeiros

    2008-07-01

    This paper aims to analyze the potential of palm-oil biodiesel production and consumption in remote Amazonian systems (not connected to the national grid), taking into account economic, social and environmental impacts of this biofuel alternative. Through a detailed analysis of remote systems and in particular the examination of the national subside called 'Combustible Consumption Account', the study presents potential scenarios of biodiesel demand for electricity generation in the region, considering also the generation and grid connections projects in forthcoming years. Definition of current and future quantities of biodiesel needed to maintain thermal production in this system defines the Biodiesel investment necessities in remote Amazonian states (Acre, Amapa, Amazonas, Para, Rondonia, Roraima). Possibility of using biodiesel made progress with the launch of the National Program of Production and Use of Biodiesel (PNPB) in 2004. Although African Palm-oil trees adapt very well Amazonian soil, wide adoption of this specie as raw material for biodiesel production shows some barriers, like raise of palm oil price in global market, palm tree long maturation time and attractive price for conventional diesel in the region. Even if using palmoil biodiesel result in obvious significant social and environmental benefits, these benefits tend not to compensate the inefficiency of the market and, thus, expand the biofuel production in the Northern Region. (author)

  7. Analysis of the potential use of palm oil biodiesel for power generation in Amazonian remote systems; Analise do potencial do biodiesel de dende para geracao eletrica em sistemas isolados da Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Anamelia Medeiros

    2008-07-01

    This paper aims to analyze the potential of palm-oil biodiesel production and consumption in remote Amazonian systems (not connected to the national grid), taking into account economic, social and environmental impacts of this biofuel alternative. Through a detailed analysis of remote systems and in particular the examination of the national subside called 'Combustible Consumption Account', the study presents potential scenarios of biodiesel demand for electricity generation in the region, considering also the generation and grid connections projects in forthcoming years. Definition of current and future quantities of biodiesel needed to maintain thermal production in this system defines the Biodiesel investment necessities in remote Amazonian states (Acre, Amapa, Amazonas, Para, Rondonia, Roraima). Possibility of using biodiesel made progress with the launch of the National Program of Production and Use of Biodiesel (PNPB) in 2004. Although African Palm-oil trees adapt very well Amazonian soil, wide adoption of this specie as raw material for biodiesel production shows some barriers, like raise of palm oil price in global market, palm tree long maturation time and attractive price for conventional diesel in the region. Even if using palmoil biodiesel result in obvious significant social and environmental benefits, these benefits tend not to compensate the inefficiency of the market and, thus, expand the biofuel production in the Northern Region. (author)

  8. Diseño de imágenes para ciegos, material didáctico para niños con discapacidad visual.

    OpenAIRE

    FUENTES NIEVES, FABIOLA MIREYA

    2014-01-01

    El objetivo de este proyecto es contribuir investigación para la creación, la aplicación, la transformación del quehacer profesional del diseño gráfico en el conocimiento y las habilidades, en la formación de profesionales en el área del diseño para material didáctico para esta disciplina, por lo cual es necesario cambiar respuestas para lo local y/o para la globalización. En la historia del diseño, se plantea, proyectar para la globalización, para la humanidad. Ahora el planteamiento de r...

  9. Visualization of water on through-plane direction of GDL using X-ray radiography

    International Nuclear Information System (INIS)

    Kim, Jongrok; Je, Junho; Kim, MooHwan; Kim, TaeJoo; Kaviany, Massoud; Son, Sang Young

    2010-01-01

    In this investigation, we visualized water distribution and behavior of water on through plane direction of GDL (Gas Diffusion Layer), which is one of components of PEMFC, using X-ray radiography. In order to investigate water distribution and behavior at GDL of PEMFC, the facilities was set up at the 7B2 beam line in Pohang Accelerator Laboratory. The phenomena of cathode side GDL is more important because the cathode side GDL has more water than the anode side. For this reason, the cathode side GDL was targeted and test section (Figure 1) was made to make similar boundary condition with a cathode side GDL of operating PEMFC. GDL faced two single channels. One is air channel as cathode gas channel of PEMFC and the other is liquid channel as cathode catalyst layer. Water is produced in cathode catalyst layer and almost of this water transport through cathode GDL. Because of this, liquid channel was adopted as catalyst layer. Images of water distribution were recorded per 4 second under various liquid pressure conditions. Water content was calculated from these images using mathematic process.

  10. Performance analysis of a solar-powered solid state heat engine for electricity generation

    International Nuclear Information System (INIS)

    Long, Rui; Li, Baode; Liu, Zhichun; Liu, Wei

    2015-01-01

    A hybrid system consisting of a CPC (compound parabolic collector) system, a SOE (solid oxide electrolyzer) system and a PEMFC (proton exchange membrane fuel cell) system was proposed to harvest solar energy. And a sensitivity analysis was conducted to evaluate the system performance. The impacts of operating temperatures of the SOE and PEMFC system, and the direct irradiation intensity of the sun on the performance characteristics were systematically analyzed. Results revealed that there exists an optimal SOE operating temperature leading to the maximum power output and maximum electrical efficiency simultaneously. Larger operating temperature of the PEMFC resulted in larger power output and higher efficiency. There also existed optimal direct irradiation intensities leading to the maximum power output and maximum electrical efficiency. Furthermore, the performance of the proposed solar energy harvesting system for practical use in real-life was also simulated. This may serve a clean technology for electricity generation. - Highlights: • A hybrid system consisting of CPC, SOE and PEMFC is proposed to harvest solar energy. • A sensitivity analysis was conducted to evaluate the system performance. • Power output and electrical efficiency have maximum values. • Performance of the proposed hybrid system for practical use was simulated.

  11. High performance electrodes for low pressure H{sub 2}-air PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Besse, S; Bronoel, G; Fauvarque, J F [Laboratoires SORAPEC (France)

    1998-12-31

    Proton exchange membrane fuel cells (PEMFCs) were first developed for space applications in the 1960s. Currently, they are being manufactured for terrestrial portable power applications. One of the challenges is to develop a low pressure H{sub 2}/Air PEMFC in order to minimize the cathodic mass transport overpotentials. The hydrogen oxidation reaction is considered to be sufficiently rapid. Hydrogen transport limitations are very low even at high current densities. The different applications considered for hydrogen/air PEMFC need to work at atmospheric pressure. An optimization of the structure of the oxygen electrode and the membrane electrode assembly (MEA) are essential in order to decrease mass transport limitations and to obtain good water management even at low pressures. Efforts have been made to produce electrodes and MEA for PEMFC with low platinum loading. The electrode structure was developed to ensure a good diffusion of reactants and an effective charge collection. It has also been optimized for low pressure restrictions. It was concluded that high performances can be achieved even at low pressures by improving the electrode gas diffusion layer (PTFE content) and by improving the catalyst. 12 refs., 7 figs.

  12. Dynamic fuzzy cognitive network approach for modelling and control of PEM fuel cell for power electric bicycle system

    International Nuclear Information System (INIS)

    Kheirandish, Azadeh; Motlagh, Farid; Shafiabady, Niusha; Dahari, Mahidzal; Khairi Abdul Wahab, Ahmad

    2017-01-01

    Highlights: •Fuzzy cognitive map was proposed for the first time to describe the behaviour of fuel cell electric bicycle system. •Fuzzy rules were applied to explain the cause and effect between concepts. •To predict and analyse the cognitive map involved in the negotiation process. -- Abstract: Modelling Proton Exchange Membrane Fuel Cell (PEMFC) is the fundamental step in designing efficient systems for achieving higher performance. Among the development of new energy technologies, modelling and optimization of energy processes with pollution reduction, sufficient efficiency and low emission are considered one of the most promising areas of study. Despite affecting factors in PEMFC functionality, providing a reliable model for PEMFC is the key of performance optimization challenge. In this paper, fuzzy cognitive map has been used for modelling PEMFC system that is directed to provide a dynamic cognitive map from the affecting factors of the system. Controlling and modification of the system performance in various conditions is more practical by correlations among the performance factors of the PEMFC derived from fuzzy cognitive maps. On the other hand, the information of fuzzy cognitive map modelling is applicable for modification of neural networks structure for providing more accurate results based on the extracted knowledge from the cognitive map and visualization of the system’s performance. Finally, a rule based fuzzy cognitive map has been used that can be implemented for decision-making to control the system. This rule-based approach provides interpretability while enhancing the performance of the overall system.

  13. The para-petroleum industry

    International Nuclear Information System (INIS)

    2002-07-01

    The para-petroleum industry includes societies that realize studies and installations for the deposits exploitation. This document presents the situation of the para-petroleum industry in 2001, the world investment growth of the activity, the french societies financial results and an inventory of the main operations in the amalgamation domain. (A.L.B.)

  14. The Douro estuarine plume: Detection, processes and dynamics =

    Science.gov (United States)

    Mendes, Renato Paulo dos Santos

    O Douro e um dos maiores rios da Peninsula Iberica, constituindo a maior descarga de agua doce para o Oceano Atlântico na costa noroeste portuguesa. A sua pluma estuarina tem particular relevância na dinâmica costeira e na modulacao de fenomenos biogeoquimicos. Sao objetivos desta dissertacao contribuir para a compreensao dos processos fisicos associados a geracao e propagacao da pluma estuarina do Rio Douro no oceano, assim como para o conhecimento dos seus padroes de dispersao e da forma como estes alteram a hidrologia e a circulacao costeira, considerando os agentes forcadores tipicos deste fenomeno (caudal fluvial, vento e mare) e indices climaticos relevantes. Para concretizacao destes objetivos foram desenvolvidas e aplicadas metodologias inovadoras de processamento de dados de detecao remota, assim como novas implementacoes estuarinas e costeiras de modelos numericos. Atraves de imagens MODIS, otimizadas para o estudo de fenomenos costeiros, efetuou-se uma detecao rigorosa da pluma. Identificou-se uma relacao entre o sinal turbido nLw555 e o caudal, demonstrando-se este produto como um bom proxy para a observacao da pluma no oceano. As escalas temporais e espaciais da pluma foram caraterizadas atraves destas imagens, combinadas com dados de caudal fluvial, mare, vento e precipitacao, e tambem com indices climaticos relevantes. Para compreender a propagacao da pluma e caracterizar a sua dinâmica e impacto na circulacao costeira, foi desenvolvida uma aplicacao 3D de modelos estuarinos e costeiros com malhas aninhadas de resolucao variavel. Definiramse e analisaram-se diferentes cenarios de vento e descarga fluvial. A interacao da pluma do Rio Douro e do Minho foi ainda analisada atraves dos resultados de simulacoes baseadas num evento de inverno. Os compositos turbidos mostraram que a pluma e facilmente detetada quando o caudal e maior que 500 m3 s??1. A descarga fluvial e o vento sao os principais forcadores da sua propagacao, enquanto a mare e apenas

  15. Summary of functional and performance test procedures

    DEFF Research Database (Denmark)

    Mitzel, Jens; Gülzow, Erich; Friedrich, K. Andreas

    Different Test Modules (TM) are defined for the functional and performance characterization of a PEMFC stack. The master document TM2.00 defines requirements and methodology for parameter variation, stability and data acquisition.......Different Test Modules (TM) are defined for the functional and performance characterization of a PEMFC stack. The master document TM2.00 defines requirements and methodology for parameter variation, stability and data acquisition....

  16. Adesao ao guia alimentar para populacao brasileira

    Directory of Open Access Journals (Sweden)

    Eliseu Verly Junior

    2013-12-01

    Full Text Available OBJETIVO : Analisar a adesão ao Guia Alimentar para População Brasileira. MÉTODOS : Amostra composta por participantes do Inquérito de Saúde de São Paulo (n = 1.661 que preencheram dois recordatórios de 24 horas. Foi utilizado modelo bivariado de efeito misto para a razão entre o consumo de energia do grupo de alimentos e o consumo calórico total. A razão estimada foi utilizada para calcular o percentual de indivíduos com consumo abaixo ou acima da recomendação. RESULTADOS : Pelo menos 80,0% da população consome abaixo do recomendado para: leite e derivados; frutas e sucos de frutas; e cereais, tubérculos e raízes; aproximadamente 60,0% para legumes e verduras; 30,0% para feijões; e 8,0% para carnes e ovos. Adolescentes apresentaram a maior inadequação para legumes e verduras (90,0%, e o estrato de maior renda foi associado à menor inadequação para óleos, gorduras e sementes oleaginosas (57,0%. CONCLUSÕES : Foi observado consumo inadequado dos grupos de alimentos relacionados com aumento do risco de doenças crônicas.

  17. Algoritmos para problemas de empacotamento

    OpenAIRE

    Eduardo Candido Xavier

    2006-01-01

    Resumo: Neste trabalho estudamos diversos problemas de empacotamento considerados NP-difíceis. Assumindo a hipótese de que P ? NP, sabemos que não existem algoritmos eficientes (complexidade de tempo polinomial) exatos para resolver tais problemas. Uma das abordagens consideradas para tratar tais problemas é a de algoritmos de aproximação, que são algoritmos eficientes e que geram soluções com garantia de qualidade. Neste trabalho apresentamos alguns algoritmos aproximados para problemas de e...

  18. Anticorrosion Coating of Carbon Nanotube/Polytetrafluoroethylene Composite Film on the Stainless Steel Bipolar Plate for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show

    2013-01-01

    Full Text Available Composite film of carbon nanotube (CNT and polytetrafluoroethylene (PTFE was formed from dispersion fluids of CNT and PTFE. The composite film showed high electrical conductivity in the range of 0.1–13 S/cm and hydrophobic nature. This composite film was applied to stainless steel (SS bipolar plates of the proton exchange membrane fuel cell (PEMFC as anticorrosion film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assembly (MEA of the PEMFC. The output power of the fuel cell is increased by 1.6 times because the decrease in the contact resistance decreases the series resistance of the PEMFC. Moreover, the coating of this composite film protects the bipolar plate from the surface corrosion.

  19. A comprehensive review of PBI-based high temperature PEM fuel cells

    DEFF Research Database (Denmark)

    Simon Araya, Samuel; Zhou, Fan; Liso, Vincenzo

    2016-01-01

    of their design and characterization techniques at single cell, stack and system levels is given. The state-of-the-art concepts of different degradation mechanisms and methods of their mitigation are also discussed. Moreover, accelerated stress testing (AST) procedures for HT-PEMFCs available in literature...... fuel cell faults for targeted interventions based on the observed conditions to prevent sudden failures and to prolong the fuel cell's lifetime. However, the technology is still under development and robust on-line diagnostics tools are hardly available. Currently, mitigation is mainly done based......The current status on the understanding of the various operational aspects of high temperature proton exchange membrane fuel cells (HT-PEMFC) has been summarized. The paper focuses on phosphoric acid-doped polybenzimidazole (PBI)-based HT-PEMFCs and an overview of the common practices...

  20. Shock and vibration effects on performance reliability and mechanical integrity of proton exchange membrane fuel cells: A critical review and discussion

    Science.gov (United States)

    Haji Hosseinloo, Ashkan; Ehteshami, Mohsen Mousavi

    2017-10-01

    Performance reliability and mechanical integrity are the main bottlenecks in mass commercialization of PEMFCs for applications with inherent harsh environment such as automotive and aerospace applications. Imparted shock and vibration to the fuel cell in such applications could bring about numerous issues including clamping torque loosening, gas leakage, increased electrical resistance, and structural damage and breakage. Here, we provide a comprehensive review and critique of the literature focusing on the effects of mechanically harsh environment on PEMFCs, and at the end, we suggest two main future directions in FC technology research that need immediate attention: (i) developing a generic and adequately accurate dynamic model of PEMFCs to assess the dynamic response of FC devices, and (ii) designing effective and robust shock and vibration protection systems based on the developed models in (i).

  1. Construcción de un indicador para medir competencias básicas para la vida

    Directory of Open Access Journals (Sweden)

    Andrea Collado Chaves

    2006-01-01

    Full Text Available La necesidad de construir un indicador para cuantificar el nivel de Competencias Básicas para la Vida (CBV, nace con la evaluación los resultados de un proyecto dirigido a población joven. El propósito de ese proyecto es construir capital humano y empleabilidad en hombres y mujeres con edades entre 13 y 18 años, desertores o en riesgo de desertar del sistema educativo, sin empleo formal y que viven en ambientes de pobreza y exclusión. Una de las dimensiones de empleabilidad son las Competencias Básicas para la Vida. La dimensión de competencias básicas para la vida se refiere a aspectos de personalidad asociados con el desempeño del individuo en sus relaciones consigo mismo y con los demás. Los datos provienen de una investigación cuyo propósito consiste en evaluar los resultados de una intervención en población joven de comunidades pobres y excluidas. La construcción del indicador uso técnicas psicométricas para la validación de las distintas subdimensiones que pertenecen al concepto de competencias básicas para la vida. Según el marco conceptual este indicador está compuesto por seis dimensiones, la validación empírica hecha en este artículo incluye solamente cuatro de ellas, todas de carácter actitudinal. El indicador posee algunas ventajas en términos de la capacidad de discriminación debido a que su distribución tiende a ser normal. Sin embargo se ve afectaba por valores extremos a la izquierda del promedio y valores modales a una desviación estándar (positiva del promedio. Estos resultados serán útiles para discusiones futuras sobre los puntos de corte (baremos, el comportamiento del indicador cuando se correlaciona con deseabilidad social y la integración de la dimensión de Competencias Básicas para la Vida en el indicador de empleabilidad.

  2. Formation of Platinum Catalyst on Carbon Black Using an In‐Liquid Plasma Method for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show

    2017-01-01

    Full Text Available Platinum (Pt catalyst was formed on the surface of carbon black using an in‐liquid plasma method. The formed Pt catalyst showed the average particle size of 4.1 nm. This Pt catalyst was applied to a polymer electrolyte membrane fuel cell (PEMFC. The PEMFC showed an open voltage of 0.85 V and a maximum output power density of 216 mW/cm2.

  3. Propuesta metodológica para hacer un diagnóstico de la Educación para el Desarrollo

    Directory of Open Access Journals (Sweden)

    Francisco Javier Gómez González

    2012-01-01

    Full Text Available El presente artículo quiere dar a conocer el diseño metodológico para la elaboración de un diagnóstico de situación de la educación para el desarrollo en Castilla y León, que se ha ideado desde el Observatorio de Cooperación Internacional de la Universidad de Valladolid con el fin de que el conocimiento sobre la situación actual de la educación para el desarrollo en Castilla y León sirva de base para la formulación de una futura estrategia de acción en educación para el desarrollo en la Comunidad.

  4. Requisitos de clientes para o desenvolvimento de um implemento a fim de fechar taipas abertas para drenagem

    Directory of Open Access Journals (Sweden)

    Ulisses Giacomini Frantz

    2015-04-01

    Full Text Available O arroz irrigado é cultivado na maior parte do RS com aplainamento da superfície do solo em desnível e sistema de cultivo mínimo. Com a semeadura em solo seco, há necessidade de conformar drenos, que cortam transversalmente as taipas, na área de cultivo. Para o estabelecimento da lâmina de água definitiva, essas taipas abertas para drenagem devem ser fechadas e, para essa finalidade, não existe um equipamento específico que execute tal atividade com devida agilidade e qualidade, sendo necessário o desenvolvimento de um implemento com este fim. Ainda, para o processo de desenvolvimento de máquinas agrícolas, faz-se necessário o levantamento de uma série de informações. Na fase de projetação, essas informações são necessárias para o estabelecimento das necessidades dos clientes/usuários e dos requisitos dos clientes, para posteriormente serem transformadas em requisitos de projeto e estabelecidas as especificações de projeto. Desse modo, este trabalho objetivou determinar os requisitos dos clientes, a partir das suas necessidades, para o projeto de um implemento com a função de fechamento de taipas abertas para drenagem no arroz irrigado. As informações foram levantadas a partir de pesquisas bibliográficas e aplicação de questionários a futuros clientes/usuários. Como resultados, foram identificadas as necessidades dos clientes, assim como 25 requisitos de clientes

  5. Hiperacumulación de metales : ¿una ventaja para la planta y para el hombre?

    OpenAIRE

    Llugany i Ollé, Mercè; Tolrà Pérez, Roser; Poschenrieder, Charlotte; Barceló Coll, Juan

    2007-01-01

    La hiperacumulación es la capacidad que tienen algunas plantas para concentrar metales en sus tejidos a niveles muy por encima de los normales sin presentar síntomas de toxicidad. Estas plantas hiperacumuladoras han desarrollado mecanismos internos de tolerancia a la toxicidad por metales. Esta peculiaridad las hace útiles para el hombre como herramienta en las nuevas tecnologías de fitoremediación. Sin embargo, ¿cual es el beneficio de esta hiperacumulación de metales para la propia planta? ...

  6. Hiperacumulación de metales: ¿una ventaja para la planta y para el hombre?

    OpenAIRE

    M. Llugany; R. Tolrà; C. Poschnrieder; J. Barceló

    2007-01-01

    La hiperacumulación es la capacidad que tienen algunasplantas para concentrar metales en sus tejidos a niveles muy por encima de los normales sin presentar síntomas de toxicidad. Estas plantas hiperacumuladoras han desarrollado mecanismos internos de tolerancia a la toxicidad por metales. Esta peculiaridad las hace útiles para el hombre como herramienta en las nuevas tecnologías de fitoremediación. Sin embargo, ¿cual es el beneficio de esta hiperacumulación de metales para la propia planta? S...

  7. ¿Para que la historia?

    OpenAIRE

    Jaime Jaramillo Uribe

    1998-01-01

    Para qué sirve la historia?. ¿Puede el conocimiento del pasado darnos pautas para comprender el presente? Sobre este, como sobre tantos problemas teóricos de la historia, se han realizado largos e inacabados debates entre historiadores y filósofos. En este ensayo se acepta como eficaz la hipótesis de que conocer el origen y el desarrollo de un proceso es buen fundamento para explicarse una situación final. En el caso de la historia colombiana, se parte de la base de que al producirse la indep...

  8. Subvenciones para instituciones Directrices para gastos de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    División de Administración de Subvenciones ... En la Parte 2 del Acuerdo de Subvención estándar de IDRC se incluyen los límites ... pagar los costos de sustitución (tiempo libre para personal académico) de los investigadores principales.

  9. Zoneamento agroclimático da palma forrageira (Opuntia sp. para o estado da Paraíba

    Directory of Open Access Journals (Sweden)

    Bergson G. Bezerra

    2014-07-01

    Full Text Available A palma forrageira tornou-se, ao longo dos anos, uma importante alternativa forrageira no semiárido brasileiro (SAB principalmente em longos períodos de estiagens. Apesar de sua magnitude para a agropecuária, seu cultivo tem dispensando tratos culturais básicos e embasamento técnico-científico quanto às suas exigências climáticas. Assim, o principal objetivo deste estudo foi elaborar o zoneamento agroclimático da cultura da palma forrageira (Opuntia sp. para o estado da Paraíba. O zoneamento agroclimático da palma forrageira foi elaborado com base nos indicadores climáticos delineados na literatura e nos dados climatológicos de precipitação e temperatura (média, máxima e mínima de 97 localidades do estado da Paraíba. De acordo com os resultados obtidos, a mesorregião da Borborema é a que apresenta as condições climáticas mais favoráveis para o cultivo da palma forrageira. As mesorregiões do Agreste, Sertão e a parte do Litoral, são aptas porém com restrições. No entanto, recomenda-se o cultivo da palma forrageira em todo o território do estado da Paraíba, exceto para a parte costeira da mesorregião do Litoral e região em torno de Areia. Em ambos os casos a inaptidão ocorre em função do excesso de precipitação.

  10. Plan estratégico para la empresa Global Logistics (GL) para el periodo 2017-2019

    OpenAIRE

    Castello Manky, Luis Fernando; Grados Iturrizaga, Miguel Augusto; Hudson Okumura, Ciro

    2017-01-01

    El presente trabajo de investigación tiene como finalidad el desarrollo de un plan estratégico para la empresa Global Logistics (GL) para los años 2017 a 2019. Inicia con el análisis y diagnóstico situacional, donde se analiza el macroentorno en base al análisis PESTEL y luego se procede a analizar la industria considerando las cinco fuerzas de Porter, para, finalmente, determinar las oportunidades y amenazas que enfrenta la empresa. Una vez concluido el análisis y diagnóstico situacional, se...

  11. Procedimiento para el cierre de canteras de materiales para construcción en Cuba

    Directory of Open Access Journals (Sweden)

    Julio Montero-Matos

    2016-03-01

    Full Text Available Con el propósito de facilitar a los concesionarios de canteras de materiales para la construcción una herramienta metodológica para efectuar el cierre de estas y garantizar una minería sostenible se propuso un procedimiento en seis etapas a partir del diagnóstico realizado en 22 canteras, ubicadas en tres regiones mineras cubanas. El procedimiento busca disminuir los impactos ambientales provocados por la explotación de las canteras y ofrecer a la industria un estándar para lograr uniformidad en la planificación y ejecución del cierre con un costo mínimo.

  12. Investigations on the double gas diffusion backing layer for performance improvement of self-humidified proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Kong, Im Mo; Jung, Aeri; Kim, Min Soo

    2016-01-01

    Highlights: • The performance of self-humidified PEMFCs can be improved with double GDBL. • The effect of double GDBL on water retention capability and membrane hydration was investigated. • In addition to HFR and EIS measurements, numerical analysis was conducted. • Optimized design of double GDBL for self-humidified PEMFC was investigated. • This study provides an inspiration on how to design the double GDBL. - Abstract: In order to simplify the system configuration and downsize the volume, a proton exchange membrane fuel cell (PEMFC) needs to be operated in a self-humidified mode without any external humidifiers. However, in self-humidified PEMFCs, relatively low cell performance is a problem to be solved. In our previous study, a gas diffusion layer (GDL) containing double gas diffusion backing layer (GDBL) coated by single micro porous layer (MPL) was introduced and its effect on the cell performance was evaluated. In the present study, the effect of the double GDBL was investigated by measuring high frequency resistance (HFR) and electrochemical impedance spectroscopy (EIS). In the experiments, the HFR value was remarkably reduced, while the diameter of semicircle of EIS was increased. It means that the membrane hydration was improved due to enhanced water retention capability of the GDL despite of interrupted gas diffusion. The result of numerical analysis also showed that the water retention capability of GDL can be improved with proper structure design of double GDBL. Based on the result, optimized design of double GDBL for water retention was obtained numerically. The result of this study provides useful information on the structural design of GDBL for self-humidified PEMFCs.

  13. Natural Resource Canada`s fuel cell R and D program

    Energy Technology Data Exchange (ETDEWEB)

    Hammerli, M; Beck, N R [Natural Resources Canada, Ottawa, ON (Canada)

    1998-05-01

    The rationale for focusing fuel cell technology on the Ballard Proton exchange Membrane (PEM) system is provided. As well, research into other fuel cell types supported by Natural Resources Canada are discussed. Fuel cells are electrochemical devices that convert a fuel and an oxidant directly into electricity. Five fuel cell technologies use hydrogen as the fuel: (1) the alkaline fuel cell (AFC), (2) the proton exchange membrane fuel cell (PEMFC), (3) the phosphoric acid fuel cell (PAFC), (4) the molten carbonate fuel cell (MCFC), and (5) the solid oxide fuel cell (SOFC). The PEMFC is suitable for transportation applications because it does not contain a liquid electrolyte and it operates at about 80 degrees C. Trials on municipal bus systems are currently underway in Vancouver and Chicago. PEMFC stacks are supplied by Ballard Power Systems of Burnaby, BC, a recognized world leader in PEMFC technology. Daimler-Benz is demonstrating the methanol reformer on its NECAR-3, powered with a Ballard PEMFC. Ballard is also designing and producing two prototype fuel cell engines for the Ford Motor Company which will integrate them into its P2000 prototype vehicle platform. The Ballard technology is also suitable for distributed power generation up to about five MW, as well as for cogeneration, when fuelled with natural gas. Stuart Energy Systems (SES) has developed an advanced UNICELL-CLUSTER{sup T}M, which permits a direct coupling of the PV array to the electrolyser, a project which demonstrates the use of solar-electrolytic hydrogen production. SES is also designing a refuelling system for the BC Transit System in Vancouver for refuelling their three Zero Emission urban transit buses powered by Ballard fuel cell engines.

  14. A comparison of sodium borohydride as a fuel for proton exchange membrane fuel cells and for direct borohydride fuel cells

    Science.gov (United States)

    Wee, Jung-Ho

    Two types of fuel cell systems using NaBH 4 aqueous solution as a fuel are possible: the hydrogen/air proton exchange membrane fuel cell (PEMFC) which uses onsite H 2 generated via the NaBH 4 hydrolysis reaction (B-PEMFC) at the anode and the direct borohydride fuel cell (DBFC) system which directly uses NaBH 4 aqueous solution at the anode and air at the cathode. Recently, research on these two types of fuel cells has begun to attract interest due to the various benefits of this liquid fuel for fuel cell systems for portable applications. It might therefore be relevant at this stage to evaluate the relative competitiveness of the two fuel cells. Considering their current technologies and the high price of NaBH 4, this paper evaluated and analyzed the factors influencing the relative favorability of each type of fuel cell. Their relative competitiveness was strongly dependent on the extent of the NaBH 4 crossover. When considering the crossover in DBFC systems, the total costs of the B-PEMFC system were the most competitive among the fuel cell systems. On the other hand, if the crossover problem were to be completely overcome, the total cost of the DBFC system generating six electrons (6e-DBFC) would be very similar to that of the B-PEMFC system. The DBFC system generating eight electrons (8e-DBFC) became even more competitive if the problem of crossover can be overcome. However, in this case, the volume of NaBH 4 aqueous solution consumed by the DBFC was larger than that consumed by the B-PEMFC.

  15. Modeling two-phase flow in three-dimensional complex flow-fields of proton exchange membrane fuel cells

    Science.gov (United States)

    Kim, Jinyong; Luo, Gang; Wang, Chao-Yang

    2017-10-01

    3D fine-mesh flow-fields recently developed by Toyota Mirai improved water management and mass transport in proton exchange membrane (PEM) fuel cell stacks, suggesting their potential value for robust and high-power PEM fuel cell stack performance. In such complex flow-fields, Forchheimer's inertial effect is dominant at high current density. In this work, a two-phase flow model of 3D complex flow-fields of PEMFCs is developed by accounting for Forchheimer's inertial effect, for the first time, to elucidate the underlying mechanism of liquid water behavior and mass transport inside 3D complex flow-fields and their adjacent gas diffusion layers (GDL). It is found that Forchheimer's inertial effect enhances liquid water removal from flow-fields and adds additional flow resistance around baffles, which improves interfacial liquid water and mass transport. As a result, substantial improvements in high current density cell performance and operational stability are expected in PEMFCs with 3D complex flow-fields, compared to PEMFCs with conventional flow-fields. Higher current density operation required to further reduce PEMFC stack cost per kW in the future will necessitate optimizing complex flow-field designs using the present model, in order to efficiently remove a large amount of product water and hence minimize the mass transport voltage loss.

  16. Design of flexible polyphenylene proton-conducting membrane for next-generation fuel cells.

    Science.gov (United States)

    Miyake, Junpei; Taki, Ryunosuke; Mochizuki, Takashi; Shimizu, Ryo; Akiyama, Ryo; Uchida, Makoto; Miyatake, Kenji

    2017-10-01

    Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems.

  17. Desenvolvimento de filmes biodegradáveis para cobertura de solo, ensacamento de frutos e sacos para mudas

    OpenAIRE

    Ana Paula Bilck

    2010-01-01

    Filmes plásticos de polietileno e polipropileno derivados do petróleo são amplamente utilizados na agricultura para a confecção de estufas, sacos para produção de mudas e filmes para cobertura do solo. Estes filmes constituem um sério problema ambiental, pois devido ao seu elevado peso molecular e propriedades hidrofóbicas, possuem alta estabilidade química, levando um longo tempo para se decompor totalmente e também são de difícil reciclagem. A utilização de polímeros biodegradáveis é uma al...

  18. On the effective diffusivity of gases in PEM fuel cell electrodes

    International Nuclear Information System (INIS)

    Karan, K.; Pharoah, J.G.

    2004-01-01

    'Full text:' Gas diffusion layer of polymer electrolyte membrane fuel cells (PEMFCs) play a critically important and multiple role as reactant gas distributor, medium for electron and water transport. The most commonly used GDL material is either carbon cloth or carbon paper. Scanning electron microscopic analysis reveals that the GDL microstructure resembles the structure of randomly laid out fibres. Almost all publications on PEMFC models have treated diffusive transport of chemical species through the porous gas diffusion layer (GDL) using correlations originally derived for isotropic granular porous media. Unfortunately, the GDL microstructure does not resemble such a structure. This paper questions the validity of effective diffusivity models used in PEMFC literature and shows that the choice of diffusivity model has significant impact on the prediction of local species fluxes and composition, and consequently on local current densities. (author)

  19. Simulation of an air conditioning absorption refrigeration system in a co-generation process combining a proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Pilatowsky, I.; Gamboa, S.A.; Rivera, W. [Centro de Investigacion en Energia - UNAM, Temixco, Morelos (Mexico); Romero, R.J. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas - UAEM, Cuernavaca, Morelos (Mexico); Isaza, C.A. [Universidad Pontificia Bolivariana, Medellin (Colombia). Instituto de Energia y Termodinamica; Sebastian, P.J. [Centro de Investigacion en Energia - UNAM, Temixco, Morelos (Mexico); Cuerpo Academico de Energia y Sustentabilidad-UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Moreira, J. [Cuerpo Academico de Energia y Sustentabilidad-UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-10-15

    In this work, a computer simulation program was developed to determine the optimum operating conditions of an air conditioning system during the co-generation process. A 1 kW PEMFC was considered in this study with a chemical/electrical theoretical efficiency of 40% and a thermal efficiency of 30% applying an electrical load of 100%. A refrigeration-absorption cycle (RAC) operating with monomethylamine-water solutions (MMA-WS), with low vapor generation temperatures (up to 80 C) is proposed in this work. The computer simulation was based on the refrigeration production capacity at the maximum power capacity of the PEMFC. Heat losses between the fuel cell and the absorption air conditioning system at standard operating conditions were considered to be negligible. The results showed the feasibility of using PEMFC for cooling, increasing the total efficiency of the fuel cell system. (author)

  20. The Solid-Phase Synthesis of an Fe-N-C Electrocatalyst for High-Power Proton-Exchange Membrane Fuel Cells.

    Science.gov (United States)

    Liu, Qingtao; Liu, Xiaofang; Zheng, Lirong; Shui, Jianglan

    2018-01-26

    The environmentally friendly synthesis of highly active Fe-N-C electrocatalysts for proton-exchange membrane fuel cells (PEMFCs) is desirable but remains challenging. A simple and scalable method is presented to fabricate Fe II -doped ZIF-8, which can be further pyrolyzed into Fe-N-C with 3 wt % of Fe exclusively in Fe-N 4 active moieties. Significantly, this Fe-N-C derived acidic PEMFC exhibits an unprecedented current density of 1.65 A cm -2 at 0.6 V and the highest power density of 1.14 W cm -2 compared with previously reported NPMCs. The excellent PEMFC performance can be attributed to the densely and atomically dispersed Fe-N 4 active moieties on the small and uniform catalyst nanoparticles. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Influence of Silica/Sulfonated Polyether-Ether Ketone as Polymer Electrolyte Membrane for Hydrogen Fueled Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2011-12-01

    Full Text Available The operation of non-humidified condition of proton exchange membrane fuel cell (PEMFC using composite sPEEK-silica membrane is reported. Sulfonated membrane of PEEK is known as hydrocarbon polyelectrolyte membrane for PEMFC and direct methanol fuel cell (DMFC. The state of the art of fuel cells is based on the perluorosulfonic acid membrane (Nafion. Nafion has been the most used in both PEMFC and DMFC due to good performance although in low humidified condition showed poor current density. Here we reported the effect of silica in hydrocarbon sPEEK membrane that contributes for a better water management system inside the cell, and showed 0.16 W/cm2 of power density which is 78% higher than that of non-silica modified [Keywords: composite membrane, polyether-ether ketone, silica, proton exchange membrane fuel cell].

  2. Taller para desarrollar la creatividad

    OpenAIRE

    MARTÍNEZ GUEROLA, BEATRIZ

    2015-01-01

    [ES] Partimos de la base de que la creatividad es una capacidad realmente valiosa, no solo para el ámbito artístico, si no para cualquier aspecto de la vida. Este proyecto está enfocado a un taller diseñado para que a partir de técnicas de expresión gráfico-plásticas podamos estimular y desarrollar la creatividad, principalmente en niños de tercer ciclo de primaria. Con este proyecto relacionamos el arte y la creatividad que se asocia a esté con la educación. Martínez Guerola, B. (2015). T...

  3. Sistema solar para aquecimento ambiente e aquecimento de piscinas: uma solução promissora para climas do Sul da Europa

    OpenAIRE

    Carvalho, M. J.; Neves, Ana

    2006-01-01

    A avaliação do sistema apresentado neste trabalho foi focada em sistemas que podem fornecer água quente, aquecimento ambiente e aquecimento de piscinas, e que são projectados para climas do Sul da Europa, especialmente para habitações uni-familiares. Pelas características climáticas do Sul da Europa, o aquecimento ambiente é apenas necessário para um curto período do ano, sendo para esta avaliação considerado um período de seis meses para aquecimento ambiente e um período de seis meses para a...

  4. Design and construction of a go-kart hybrid PEM fuel cell / rechargeable battery; Diseno y construccion de un go-kart hibrido pila de combustible PEM / bateria recargable

    Energy Technology Data Exchange (ETDEWEB)

    Suarez Alcantara, Karina; Rodriguez Castellanos, Andres; Soloza Feria, Omar [Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: k.suarez.alcantara@gmail.com

    2008-11-15

    An hybrid Polymer Electrolyte Membrane Fuel Cell, PEMFC-Rechargeable Battery Go-kart has been designed and manufactured using AutoCAD software for the design and a CNC mechanical machine for the manufacture of components of the fuel cell. The membrane-electrode assemblies, MEAs, were integrated with a Gore-Select membrane and carbon cloth with Pt (20 wt % /C) 0.5 mg/cm{sup 2} anode and cathode electrode catalysts loading. High density graphite collector plates with 5mm thickness were used as collector plates. The estimated weigh of the go-kart with a driver is about 120 kg. The demand of the motor of the go-kart is 20 V and 5 A (100W), supplied by an hybrid system integrated by three 30Watts PEMFC. The commercially available Pb/acid rechargeable battery supplies energy for peripheral equipment. [Spanish] En este trabajo se presenta el diseno y la construccion de un go-kart hibrido pila de combustible con membrana de conduccion protonica tipo PEM (Proton Exchange Membrane, por sus siglas en ingles) y pila recargable. El diseno de los colectores de corriente de la pila se realizo utilizando el programa AutoCAD y la construccion mediante una fresadora con control numerico, CNC. Los ensambles membrana-electrocatalizador de la pila estan formados por membranas Gore-Select y por electrodos de Pt soportado en tela de carbon al 20 %peso/C con carga de 0.5 mg /cm{sup 2}, en anodo y catodo. Los platos colectores de corriente fueron manufacturados en grafito de alta densidad con espesor de 5 mm. La caracterizacion de la pila de combustible se realizo mediante ensayos de polarizacion potenciostatica. El peso total del go-kart y una persona a bordo es de 120 kg. La potencia del go-kart es generada por un motor de corriente directa de 20 V y 5 A (100 Watts). Para tal efecto, se construyeron tres pilas de combustible de 30 W cada una, con un respaldo de baterias recargables comerciales de Pb/acido para energizar equipos perifericos.

  5. MODELO PARA DETERMINAR FUNÇÕES TRANSFERÊNCIA PARA ANÁLISE DE ESTABILIDADE DE VANTS

    Directory of Open Access Journals (Sweden)

    Igor Mayer Soares

    2017-01-01

    Full Text Available Neste trabalho foi apresentado um modelo para determinar as funções de transferência para análise da estabilidade longitudinal de Veículos Aéreos Não Tripulados (VANT através do desenvolvimento simplificado das equações do movimento de aeronaves. O sistema foi simplificado considerando que o motor e o arrasto na superfície de comando não influenciam na dinâmica do veículo, pois o mesmo é significativamente menor que um avião. Analisamos também a resposta em função do tempo para as deflexões das superfícies de comando. Nos resultados apresentados é possível perceber que mesmo simples, o modelo oferece uma boa aproximação para análise dinâmica de VANTs e predizer sua estabilidade e qualidade de voo.

  6. MODELO PARA LA CREACIÓN DEL CONOCIMIENTO PARA PYMES

    Directory of Open Access Journals (Sweden)

    Marino Valencia Rodríguez

    2009-01-01

    Full Text Available La creciente importancia del conocimiento, como nuevo factor de producción, hace que la creación y transferencia se convierta en una de las principales prioridades de las organizaciones. El presente artículo describe tanto los fundamentos de la teoría de los recursos y capacidades de la empresa como el enfoque de la gestión del conocimiento, con sus procesos de generación y transferencia del conocimiento. Estos sirven de guía básica teórica para alcanzar el siguiente objetivo: Diseñar un modelo de generación y transferencia de conocimiento para los procesos de dirección, gestión humana y del conocimiento para PyMES, con el fin de que éstas alcancen mayores niveles de competitividad. El modelo se diseña, a partir del direccionamiento estratégico de la organización. Está conformado por tres etapas, articuladas con elementos y actividades. Las acciones se enfocan en dos factores clave de éxito: la cultura organizacional y la formación. La utilización del modelo permitirá a las PyMES optimizar los recursos y capacidades disponibles, lo cual se refleja en el desempeño del trabajador y en el fortalecimiento de la cultura organizacional.

  7. Flora da Paraíba, Brasil: Loganiaceae Flora of Paraíba, Brazil: Loganiaceae

    Directory of Open Access Journals (Sweden)

    Kiriaki Nurit

    2005-06-01

    Full Text Available Neste trabalho apresenta-se o tratamento taxonômico da família Loganiaceae, como parte do projeto "Flora da Paraíba", que vem sendo realizado com o objetivo de identificar e catalogar as espécies da flora local. Realizouse coletas e observações de campo para as identificações, descrições e ilustrações botânicas que foram efetuadas após estudos morfológicos, com o auxílio da bibliografia especializada, complementados pela análise de fotos de tipos, espécimes dos herbários EAN, JPB e IPA, e comparação com material identificado por especialistas. Registrou-se para a Paraíba quatro espécies: Spigelia anthelmia L., com ampla distribuição, e três espécies de Strychnos, somente coletadas em remanescentes de Mata Atlântica, S. atlantica Krukoff & Barneby, S. parvifolia A. DC. e S. trinervis (Vell. Mart.This work constitutes a taxonomic treatment of the Loganiaceae family as part of the project "Flora da Paraíba", which have been carried out with the objective to identify and catalogue the species of the local flora. The botanical identifications and illustrations were made by morphological studies supported by bibliography, analysis of the types, specimens from herbaria EAN, JPB and IPA, and comparison with samples previously identified by specialists, complemented by field observations. Four species of Loganiaceae belonging two genera were found in State of Paraíba: Spigelia anthelmia L. that has wide distribution and three species of Strychnos, found on remains of Atlantic forest, which are S. atlantica Krukoff & Barneby, S. parvifolia A. DC. and S. trinervis (Vell. Mart.

  8. Educación para emprender una alternativa para el siglo XXI

    Directory of Open Access Journals (Sweden)

    Luis Gerardo Rodríguez Gómez

    2015-05-01

    Full Text Available RESUMEN El artículo describe la experiencia educativa del programa Físico- Deportivo orientado a estimular la actitud para emprender dentro de una concepción de forma integral, mediante Asignaturas de contenido Sico- físico, como parte del desarrollo curricular en Facultades de Administración de Empresas e ingeniería de Sistemas en la Escuela de Administración de Negocios (EAN. El desarrollo temático hace énfasis en un proceso orientado  a superar formas de educación encaminadas al logro de habilidades técnicas para el ejercicio de un empleo y propone desde  la educación delas conductas  motrices, modos de encausar la energía sicosomática con el fin de asimilar la incertidumbre del momento histórico que se vive en los países de lento desarrollo, para corresponder a un mundo que empuña la bandera de la diversidad, el cambio acelerado y la competencia tecnológica.

  9. Proton-Conducting Sulfonated and Phosphonated Polymers and Fuel Cell Membranes by Chemical Modification of Polysulfones

    OpenAIRE

    Lafitte, Benoit

    2007-01-01

    The proton exchange membrane fuel cell (PEMFC) is currently emerging as an efficient and environmentally friendly power source. The technology is very complex and relies ultimately on materials and components which need further development. One of the major hurdles for advancing the PEMFC technology is currently the demand for new durable low-cost polymeric membranes that will allow fuel cell operation at high temperatures without extensive humidification requirements. Thus, the design and pr...

  10. Proton exchange membrane fuel cell operation and degradation in short-circuit.

    OpenAIRE

    Silva , R.E.; Harel , F.; Jemei , S.; Gouriveau , Rafael; Hissel , Daniel; Boulon , L.; Agbossou , K.

    2013-01-01

    International audience; Hybridization of proton exchange membrane fuel cells (PEMFC) and ultra capacitors (UC) are considered as an alternative way to implement high autonomy, high dynamic, and reversible energy sources. PEMFC allow high efficiency and high autonomy, however their dynamic response is limited and this source does not allow recovering energy. UC appears to be a complementary source to fuel cell systems (FCS) due to their high power density, fast dynamics, and reversibility. A d...

  11. Protic Organic Ionic Plastic Crystals: Fast Solid-State Proton Conductors

    DEFF Research Database (Denmark)

    Luo, Jiangshui; Aili, David; Pan, Chao

    2016-01-01

    High temperature polymer electrolyte membrane fuel cells (PEMFCs) operating between 100 °C and 200 °C are desirable because they offer significant benefits, such as improved electrode kinetics, simpler water and heat management, and better tolerance to fuel impurities, leading to higher overall...... system efficiencies [1]. However, state-of-the-art high temperature PEMFCs suffer from leakage problems associated with liquid electrolytes, such as H3PO4 and protic ionic liquids....

  12. La carrera profesional para el profesorado

    Directory of Open Access Journals (Sweden)

    José Gimeno Sacristán

    2010-01-01

    Full Text Available La carrera del profesorado es un instrumento para el reconocimiento del mérito de los profesores en el desarrollo de su profesionalidad -lo cual supone atender a la mejora de sus capacidades cognitivas como a su competencia reflexivo-práctica- cuyos fines son la motivación para el ejercicio de sus funciones, reforzar su compromiso con la educación en general y como forma de reconocer con justicia el mérito de los mejores profesionales. Desde un punto de vista estrictamente educativo, la carrera debe servir para la mejora de las prácticas de enseñanza que incidan en la mejora de los aprendizajes. Esta pretensión nos exige explicitar los criterios para determinar lo que entendemos como buenas prácticas y precisar los criterios para su evaluación. La complejidad de la enseñanza requiere metodologías adecuadas para abordar procesos de índole cualitativa. La regulación de la carrera docente tiene que superar tanto el cuantitativismo fácil en los métodos y la regulación burocrática de niveles de calidad, así como contemplar un conjunto de incentivos no solamente salariales.

  13. Tiempo para un cambio

    Science.gov (United States)

    Woltjer, L.

    1987-06-01

    En la reunion celebrada en diciembre dei ano pasado informe al Consejo de mi deseo de terminar mi contrato como Director General de la ESO una vez que fuera aprobado el proyecto dei VLT, que se espera sucedera hacia fines de este aAo. Cuando fue renovada mi designacion hace tres aAos, el Consejo conocia mi intencion de no completar los cinco aAos dei contrato debido a mi deseo de disponer de mas tiempo para otras actividades. Ahora, una vez terminada la fase preparatoria para el VLT, Y habiendose presentado el proyecto formalmente al Consejo el dia 31 de marzo, y esperando su muy probable aprobacion antes dei termino de este ano, me parece que el 10 de enero de 1988 presenta una excelente fecha para que se produzca un cambio en la administracion de la ESO.

  14. Leasing: una alternativa de financiamiento para PYMES

    OpenAIRE

    Bedjan, María Belén

    2008-01-01

    En la actualidad las pequeñas y medianas empresas encuentran dificultades para acceder a las líneas tradicionales de créditos bancarios. Por otro lado las empresas necesitan actualizarse constantemente para poder ser competitivas en el mercado. Es aquí donde el leasing nace como una alternativa de financiación para las PyMEs. Este trabajo pretendió demostrar la conveniencia financiera del leasing con respecto a los préstamos bancarios para la compra de maquinarias agrícolas ...

  15. Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad.

    Directory of Open Access Journals (Sweden)

    Reina de los Ángeles Carballé Piñón

    2015-12-01

    Full Text Available Este trabajo "Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad" resulta de la investigación realizada para tesis de maestría; se realizó el estudio de 2 entidades, nos permitió conocer las principales posiciones que sobre motivación existen, factores que la influencian, cómo incide en el desempeño laboral y que acciones diseñar para elevarla. Las 2 entidades seleccionadas, claves en el desempeño empresarial son un centro de interfase y un centro generador de conocimientos, nuestro objetivo principal es sugerir propuestas que eleven la motivación de los trabajadores del CIGET(centro de interfase y la Universidad de Sancti Spíritus(centro generador de conocimientos por desempeñar una mejor labor y lograr así aumento de la eficacia, eficiencia y productividad; este se concreta específicamente en determinar qué factores ocasionan desmotivación en los trabajadores del CIGET y la Universidad, identificar aquellos factores que realmente motivan a estas personas, de manera individual como colectivamente y trazar una estrategia con el objetivo de elevar la motivación de los trabajadores hacia la actividad que realizan y dotar a estos de herramientas para la identificación de actitudes positivas o negativas en el ámbito laboral y cómo potenciarlas o minimizarlas según sea el caso.

  16. Competencia para desarrollar la alfabetización digital

    OpenAIRE

    González Rodríguez, José Santiago; Navarrete Aguirre, Mariana; Molina Zacate, Ma. Gabriela

    2011-01-01

    Introducción, Objetivos Generales, Temario: (1) ¿Qué significa la competencia para desarrollar la alfabetización digital? (2) ¿Por qué es relevante que adquiera la competencia para desarrollar la alfabetización digital en mi formación? (3) ¿Cómo aprendo la competencia para desarrollar la alfabetización digital? (4) ¿Cómo aplico la competencia para desarrollar la alfabetización digital? (5) ¿Cómo puedo autoevaluar mi competencia para desarrollar la alfabetización digital (...

  17. Motivacao para o tratamento. Dados psicometricos da escala SOCRATES 8D e estrategias psicoterapeuticas para motivar para o tratamento

    OpenAIRE

    Janeiro, Luís; Faísca, Luís

    2008-01-01

    A motivação para o tratamento é considerada um factor fundamental para o processo de mudança e tratamento do toxicodependente. Prochaska, Diclemente, e Norcross (1992) consideram que a motivação que o sujeito possui no início do tratamento determina directamente os resultados alcançados no mesmo. Diclemente, Bellino, e Neavins (1999) acrescentam, ainda, que a estreita relação entre os resultados obtidos no tratamento e a motivação aquando do seu início pode ser medida pela formação precoce de...

  18. La estrategia educativa 2020 o las limitaciones del Banco Mundial para promover el "aprendizaje para todos"

    Directory of Open Access Journals (Sweden)

    Antoni Verger

    2011-12-01

    Full Text Available LA NUEVA Estrategia Educativa 2020 del Banco Mundial establece las prioridades de reforma educativa en países en vías de desarrollo para la década siguiente. El título explícito de la estrategia, Aprendizaje para Todos, es un claro reconocimiento de que, más allá de políticas centradas en el acceso, se debe hacer algo más para asegurar que la educación derive en experiencias positivas de aprendizaje. Sin embargo, como este artículo sostiene, las opciones de políticas explícitas y latentes en la Estrategia 2020 no son las más adecuadas para lograr el Aprendizaje para Todos. El artículo desarrolla tres tipos de argumentos al respecto. El primero se refiere al fuerte apego del Banco a un conocimiento disciplinario y un enfoque metodológico que es insuficiente para entender lo que aprenden los niños en la escuela y por qué. El segundo argumento se refiere al sesgo pro-mercado de la Estrategia por lo que respecta a la reforma del sector público y a nuevas formas de oferta educativa. En tercer lugar, el artículo señala las principales ausencias de la Estrategia, con especial atención a las omisiones relacionadas con la compleja relación entre educación y pobreza.

  19. Inteligencia Emocional para tiempos de crisis

    OpenAIRE

    Fernández-Berrocal, Pablo

    2014-01-01

    La Inteligencia Emocional se concibe como un conjunto de habilidades, tanto básicas como complejas, dirigidas a “unificar las emociones y el razonamiento”, esto es, usar las emociones para facilitar el razonamiento y los procesos de pensamiento, y usar nuestro razonamiento para pensar de forma inteligente acerca de nuestras emociones (Mayer y Salovey, 1997). En concreto, la IE se define como una habilidad mental que incluye “la capacidad para percibir, valorar y expresar las emociones con...

  20. GRASP para o PQA: um limite de aceitação para soluções iniciais

    Directory of Open Access Journals (Sweden)

    Range Maria Cristina

    2000-01-01

    Full Text Available O Problema Quadrático de Alocação (PQA pertence à classe dos problemas NP-Hard e desafia os pesquisadores tanto em sua teoria quanto em sua parte computacional. Pela sua alta complexidade muitos métodos heurísticos têm sido desenvolvidos para tentar resolvê-lo aproximadamente. A metaheurística GRASP (greedy randomized adaptive search procedures se mostrou bastante eficiente. Neste trabalho, uma proposta para descartar soluções iniciais supostamente ruins é apresentada com base na normalização de custos calculadas num intervalo entre limites de solução. Para este GRASP restrito, foi observada uma redução do tempo computacional para encontrar as soluções ótimas ou soluções viáveis de boa qualidade quando comparado ao GRASP original.

  1. Paisajes para un desarrollo sustentable y participativo

    Directory of Open Access Journals (Sweden)

    Rafael Mata Olmo

    2014-11-01

    Para terminar, el texto recoge una experiencia de proyecto territorial de paisaje, la del Plan Insular de Menorca (Islas Baleares, España, aprobado en 2003. Se sintetizan sus determinaciones sobre la protección de determinados terrenos por sus altos valores paisajísticos, sus directrices para que las políticas sectoriales (turismo, agricultura, infraestructuras, etc. incorporen criterios paisajísticos, y sus iniciativas para la gestión y mejora del paisaje y para el fomento del acceso público a su contemplación y disfrute.

  2. Sistema de realidad aumentada para aplicaciones Android

    OpenAIRE

    Fernández Sánchez, Natalia Mercedes

    2012-01-01

    El objetivo principal de este proyecto es la creación de un sistema de realidad aumentada para el sistema operativo Android con idea de que sea utilizado para la creación de un videojuego, pero que a su vez sea lo suficientemente versátil como para poder utilizarse en otro tipo de aplicaciones. De este objetivo principal podemos obtener los objetivos secundarios: - Conocer las características que ofrecen los teléfonos móviles y como éstas pueden ser aprovechadas para la crea...

  3. Marco de referencia para el desarrollo de un sistema de apoyo para la toma de decisiones para la gestión de inventarios

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Castro Zuluaga

    2014-01-01

    Full Text Available El principal objetivo de este artículo es presentar un marco de referencia para desarrollar un sistema de soporte a la toma de decisiones para la gestión de inventarios que permita definir técnicamente los parámetros de una política de control de inventario específica. El modelo propuesto puede ser utilizado de forma genérica en casi cualquier tipo de industria, el cual incluye las entradas fundamentales, una descripción de los procesos internos requeridos y las salidas esperadas. En la investigación se utilizaron métodos inductivos-deductivos para definir el marco de referencia propuesto, el cual se fundamenta en dos indicadores clave en la gestión de inventario: niveles de servicio y costos. Finalmente, mediante una simulación es posible concluir que utilizando los parámetros teóricos para el modelo de inventario punto de reorden-cantidad fija, que son encontrados por el marco de referencia propuesto, se obtienen aproximadamente los valores esperados tanto de los niveles de servicio como de los costos.

  4. Meios e fins do desenvolvimento para Celso Furtado

    Directory of Open Access Journals (Sweden)

    Fabio Antonio de Campos

    2014-10-01

    Full Text Available O objetivo desse artigo é expor o conceito de desenvolvimento para Celso Furtado. Para tanto, nos interessa apresentar o desenvolvimento nacional como um fim em sua abordagem sobre a formação social brasileira Para atingir tal estágio, os meios para o autor seriam assegurados por um típico desenvolvimento capitalista. Dentro dessa problemática, mostraremos também o alcance e os limites dessa concepção para o caráter dependente e subdesenvolvido do capitalismo brasileiro.

  5. Metodología para un proceso de planeación estratégica para las PYMES

    OpenAIRE

    Bonilla Zhindón, Daniela

    2014-01-01

    Todas las organizaciones, grandes, medianas, pequeñas, públicas y privadas, requieren de un plan estratégico estructurado para determinar las posiciones futuras en las que desean estar, por este motivo el propósito del presente estudio es construir una metodología transversal para el levantamiento de la planeación estratégica para el sector de calzado en la ciudad de Cuenca, mediante un análisis del estado en la que se encuentran las empresas en cuanto al proceso de planificación estratégica,...

  6. Coccocypselum pulchellum (Rubiaceae, nuevo registro para Argentina

    Directory of Open Access Journals (Sweden)

    Elsa L. Cabral

    2007-01-01

    Full Text Available Se cita Coccocypselum pulchellum por primera vez para Argentina, en Predio Guaraní, Misiones. Esta es la tercera especie de Coccocypselum registrada para la flora de Argentina junto con C. hasslerianum y C. lanceolatum. Se incluyen descripciones, ilustraciones y una clave para reconocer las tres especies argentinas de Coccocypselum.

  7. Modelo para determinar as exigências de proteína para poedeiras Modelling protein utilization in laying hens

    Directory of Open Access Journals (Sweden)

    Nilva Kazue Sakomura

    2002-11-01

    Full Text Available O objetivo do trabalho foi elaborar um modelo para estimar as exigências de proteína bruta (PB para poedeiras leves, usando o método fatorial. Para determinar as exigências de proteína bruta (PB para manutenção foi utilizada a técnica do balanço de nitrogênio. A exigência de proteína bruta para o ganho de peso foi determinada em função do conteúdo de nitrogênio na carcaça e a eficiência de utilização do nitrogênio da dieta. A exigência de PB, para produção de ovos, foi determinada considerando o teor de PB determinado nos ovos e a eficiência de deposição do nitrogênio no ovo. A partir dos valores das exigências para manutenção, para o ganho e produção foi elaborada uma equação para predizer as exigências diárias de PB (g/ ave/ dia para poedeiras: PB = 1,94. P0,75 + 0,48.G + 0,301.O, em que P = peso corporal (kg, G = ganho de peso diário (g/dia e O = massa de ovos produzida (g/ave/dia.The objective of this study was to determine a model for crude protein requirements (CP for laying hen by the factorial method. The protein maintenance requirement was determine by the nitrogen balance technique . The crude protein requirement for weight gain was determined based on body nitrogen content and nitrogen efficiency for body deposition. The crude protein requirement for egg production was determined based on the nitrogen content of eggs and nitrogen efficiency for egg deposition. Considering the requirements for maintenance, egg production and weight gain, it was elaborated a protein requirement model for laying hen: PB = 1.94xW.75 + 0.480xG + 0,301x E, where PB = requirement (g/bird/day, W = body weight (kg, G = daily weight gain (g/day and E = egg mass (g/bird/day.

  8. Further insights into the durability of Pt3Co/C electrocatalysts: Formation of “hollow” Pt nanoparticles induced by the Kirkendall effect

    International Nuclear Information System (INIS)

    Dubau, L.; Durst, J.; Maillard, F.; Guétaz, L.; Chatenet, M.; André, J.; Rossinot, E.

    2011-01-01

    Highlights: ► Pt 3 Co/C electrocatalysts for the oxygen reduction reaction. ► During operation in a PEMFC, Co atoms are depleted from the mother electrocatalyst. ► The structure of the Pt–Co/C electrocatalysts in the long-term is determined by a balance between Co surface segregation and formation of oxygenated species from water. ► The presence of Co atoms in the subsurface region severely depreciates the oxygen reduction reaction activity. ► “Hollow” Pt nanoparticles have been detected for the first time in a PEMFC. - Abstract: This paper provides further insights into the degradation mechanisms of nanometer-sized Pt 3 Co/C particles under various proton-exchange membrane fuel cell (PEMFC) operating conditions. We confirm that Co atoms are continuously depleted from the mother Pt 3 Co/C electrocatalyst because they can diffuse from the bulk to the surface of the material. The structure of the Pt–Co/C nanoparticles in the long-term is determined by a balance between Co surface segregation and formation of oxygenated species from water splitting. When the PEMFC is operated at high current density (low cathode potential, below the onset of surface oxide formation from water), a steady-state is reached between the rate of Co dissolution at the surface and Co surface segregation. Consequently, Co and Pt atoms remain homogeneously distributed within the Pt–Co/C particles and the thickness of the Pt-shell is maintained to a small value not detectable by atomic-resolution high-angle annular dark-field scanning transmission electron microscopy. When the PEMFC is operated at low current density (high cathode potential), the formation of surface oxides from water and the resulting “place-exchange” mechanism enhance the rate of diffusion of Co atoms to the surface. Consequently, the fresh Pt 3 Co/C particles form core/shell particles with thick Pt-shells and Co content < 5 at% and, ultimately, “hollow” Pt nanoparticles (Kirkendall effect). To the

  9. Tools for designing the cooling system of a proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Soupremanien, Ulrich; Le Person, Stéphane; Favre-Marinet, Michel; Bultel, Yann

    2012-01-01

    Proton exchange membrane fuel cell (PEMFC) requires a careful management of the heat distribution inside the stack. The proton exchange membrane is the most sensitive element of this thermal management and it must operate under specific conditions in order to increase the lifetime and also the output power of the fuel cell. These last decades, the enhancement of the output power of the PEMFC has led the manufacturers to greatly improve the heat transfer effectiveness for cooling such systems. In addition, homogenizing the bipolar plate temperature increases the lifetime of the system by limiting the occurrence of strong thermal gradients. In this context, using a fluid in boiling conditions to cool down the PEMFC seems to be very suitable for this purpose. In order to compare the thermal performances between a coolant used in single-phase flow or in boiling flow conditions, we have built an experimental set-up allowing the investigation of cooling flows for these two conditions. Moreover, the geometry of the cooling channels is one of the key parameters which allows the improvement of the thermal performances. Indeed, the size or the aspect ratio of these channels could be designed in order to decrease the thermal system response. The sizing of the fuel cell cooling system is of paramount importance in boiling flow conditions because it can modify, not only the pressure losses along the channel and the heat transfer coefficient like in a single-phase flow but also, the onset of nucleate boiling (ONB) and the dryout point or critical heat flux (CHF). Thus, in order to understand some heat transfer mechanisms, which are geometry-dependent, a parametric study was completed by considering flows in four different rectangular channels. Finally, this study allows a better insight on the optimization of the geometrical parameters which improve the thermal performances of a PEMFC, from a cooling strategy aspect point of view. - Highlights: ► Parameters for the using of a

  10. Using qualimetric engineering and extremal analysis to optimize a proton exchange membrane fuel cell stack

    International Nuclear Information System (INIS)

    Besseris, George J.

    2014-01-01

    Highlights: • We consider the optimal configuration of a PEMFC stack. • We utilize qualimetric engineering tools (Taguchi screening, regression analysis). • We achieve analytical solution on a restructured power-law fitting. • We discuss the Pt-cost involvement in the unit and area minimization scope. - Abstract: The optimal configuration of the proton exchange membrane fuel-cell (PEMFC) stack has received attention recently because of its potential use as an isolated energy distributor for household needs. In this work, the original complex problem for generating an optimal PEMFC stack based on the number of cell units connected in series and parallel arrangements as well as on the cell area is revisited. A qualimetric engineering strategy is formulated which is based on quick profiling the PEMFC stack voltage response. Stochastic screening is initiated by employing an L 9 (3 3 ) Taguchi-type OA for partitioning numerically the deterministic expression of the output PEMFC stack voltage such that to facilitate the sizing of the magnitude of the individual effects. The power and current household specifications for the stack system are maintained at the typical settings of 200 W at 12 V, respectively. The minimization of the stack total-area requirement becomes explicit in this work. The relationship of cell voltage against cell area is cast into a power-law model by regression fitting that achieves a coefficient of determination value of 99.99%. Thus, the theoretical formulation simplifies into a non-linear extremal problem with a constrained solution due to a singularity which is solved analytically. The optimal solution requires 22 cell units connected in series where each unit is designed with an area value of 151.4 cm 2 . It is also demonstrated how to visualize the optimal solution using the graphical method of operating lines. The total area of 3270.24 cm 2 becomes a new benchmark for the optimal design of the studied PEMFC stack configuration. It is

  11. Tuberculose em Salvador: custos para o sistema de saúde e para as famílias

    Directory of Open Access Journals (Sweden)

    Costa João G

    2005-01-01

    Full Text Available OBJETIVO: A tuberculose é uma das maiores causas de mortalidade no mundo, porém seus efeitos econômicos são pouco conhecidos. O objetivo do estudo foi o de estimar os custos do tratamento e prevenção da tuberculose para o sistema de saúde (público e privado e para as famílias. MÉTODOS: O estudo foi realizado no município de Salvador, BA, em 1999. Os dados para estimação dos custos para o sistema de saúde foram coletados nas secretarias de saúde, centros de saúde e em uma entidade filantrópica. Os custos públicos e privados foram estimados pela metodologia da contabilidade de custos. Os dados de custos para as famílias foram coletados por meio de questionários e incluem despesas com transporte, alimentação e outros, bem como as perdas de renda associadas à doença. RESULTADOS: O custo médio para tratamento de um caso novo de tuberculose foi de aproximadamente R$186,00 (US$103; para o tratamento de um paciente multiresistente o custo foi 27 vezes mais alto. Os custos para o serviço público corresponderam a 65% em internações, 32% em tratamento e apenas 3% em prevenção. As famílias comprometeram cerca de 33% da sua renda com despesas relacionadas a tuberculose. CONCLUSÕES: Apesar do fato das famílias não terem que pagar por medicamentos e tratamento, dado que este serviço é oferecido pelo Estado, os custos familiares ligados a perda de rendimentos devido a doença foram muito elevados. A proporção utilizada em prevenção pelo serviço público é pequena. Um maior investimento em campanhas de prevenção poderia não somente diminuir o número de casos, mas também, levar a um diagnósticos precoce, diminuindo os custos associados à hospitalização. A falta de um sistema integrado de custos não permite a visualização dos custos nos diversos setores.

  12. Gram-Scale Synthesis of Highly Active and Durable Octahedral PtNi Nanoparticle Catalysts for Proton Exchange Membrane Fuel Cell

    DEFF Research Database (Denmark)

    Choi, Juhyuk; Jang, Jue-Hyuk; Roh, Chi-Woo

    2018-01-01

    for the commercialization of PEMFCs. In this study, we focus on gram-scale synthesis of octahedral PtNi nanoparticles with Pt overlayers (PtNi@Pt) supported on the carbon, resulting in enhanced catalytic activity and durability. Such PtNi@Pt catalysts show high mass activity (1.24 A mgPt−1) at 0.9 V (vs RHE) for the ORR......Proton exchange membrane fuel cells (PEMFC) are regarded as a promising renewable energy source for a future hydrogen energy society. However, highly active and durable catalysts are required for the PEMFCs because of their intrinsic high overpotential at the cathode and operation under the acidic...... condition for oxygen reduction reaction (ORR). Since the discovery of the exceptionally high surface activity of Pt3Ni(111), the octahedral PtNi nanoparticles have been synthesized and tested. Nonetheless, their milligram-scale synthesis method and poor durability make them unsuitable...

  13. Novel Blend Membranes Based on Acid-Base Interactions for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yongzhu Fu

    2012-10-01

    Full Text Available Fuel cells hold great promise for wide applications in portable, residential, and large-scale power supplies. For low temperature fuel cells, such as the proton exchange membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs, proton-exchange membranes (PEMs are a key component determining the fuel cells performance. PEMs with high proton conductivity under anhydrous conditions can allow PEMFCs to be operated above 100 °C, enabling use of hydrogen fuels with high-CO contents and improving the electrocatalytic activity. PEMs with high proton conductivity and low methanol crossover are critical for lowering catalyst loadings at the cathode and improving the performance and long-term stability of DMFCs. This review provides a summary of a number of novel acid-base blend membranes consisting of an acidic polymer and a basic compound containing N-heterocycle groups, which are promising for PEMFCs and DMFCs.

  14. Effect of atomic composition on the compressive strain and electrocatalytic activity of PtCoFe/sulfonated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Lohrasbi, Elaheh [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Javanbakht, Mehran, E-mail: mehranjavanbakht@gmail.com [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Fuel and Solar Cell Lab, Renewable Energy Research Center, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Mozaffari, Sayed Ahmad [Fuel and Solar Cell Lab, Renewable Energy Research Center, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Thin Layer and Nanotechnology Laboratory, Department of Chemical Technology, Iranian Research Organization for Science and Technology (IROST), Tehran (Iran, Islamic Republic of)

    2017-06-15

    Highlights: • SO{sub 3}H-graphene supported PtFeCo alloy nanoparticles were prepared. • Co:Fe atomic ratio plays important role in the electrocatalytic performance. • PtCoFe/SG with 7:3 Co:Fe atomic ratio is optimized for PEMFCs. • Power density of 530 mW cm{sup −2} with 0.1 mg cm{sup −2} Pt loading was obtained at 75 °C. - Abstract: The aim of this work is improvement of the stability and durability of sulfonated graphene supported PtCoFe electrocatalyst (PtCoFe/SG) for application in proton exchange membrane fuel cells (PEMFCs). The durability investigation of PtCoFe/SG is evaluated by a repetitive potential cycling test. The compressive strain in the lattice of PtCoFe/SG towards the electrocatalytic oxygen reduction reaction is studied. The synthesized electrocatalysts are examined physically and electrochemically for their structure, morphology and electrocatalytic performance. It is shown that presence of SO{sub 3}− groups on the graphene cause better adsorption of PtCoFe nanoparticles on the support and increase stability of electrocatalysts. Also, it is shown that Co:Fe atomic ratio in the synthesized electrocatalysts plays important role in their electrocatalytic performance. In the optimum Co:Fe atomic ratio, the compressive strain goes through the ideal value of the binding energy; further increase in Co/Fe atomic fraction introduces the excessive compressive strain and the activity of electrocatalyst decreases. The electrocatalyst synthesized in the optimum conditions is utilized as cathode in PEMFC. The power density of the PEMFC in low metal loading (0.1 mg cm{sup −2} Pt) reaches to a maximum of 530 mW cm{sup −2} at 75 °C. It suggests that PtCoFe/SG with 7:3 Co:Fe atomic ratio promises to improve the power density of PEMFCs.

  15. Experimental study on the self-humidification effect in proton exchange membrane fuel cells containing double gas diffusion backing layer

    International Nuclear Information System (INIS)

    Kong, Im Mo; Choi, Jong Won; Kim, Sung Il; Lee, Eun Sook; Kim, Min Soo

    2015-01-01

    Highlights: • Investigated self-humidification effect of structurally modified GDBLs in PEMFCs. • One conventional and two modified GDLs were prepared. • Structural design of the GDBLs significantly affected self-humidification. • Stacking was found to have negligible effect on self-humidification. • It can be applied readily to self-humidified PEMFCs. - Abstract: Adequate hydration of the membrane is required to ensure high proton conductivity in proton exchange membrane fuel cells (PEMFCs), which, in turn, is required for achieving high cell performances. While external humidifiers are typically used to humidify the supplied air in conventional systems, their use increases the complexity, weight, volume, and parasitic power loss in fuel cell systems, rendering them unviable in some systems, particularly for portable applications. In this study, the structure of a gas diffusion backing layer (GDBL) was modified to enhance the self-humidification effect in PEMFCs. Three types of GDLs were prepared for the experiments: a conventional GDL (GDL-A with uniform single GDBL) and two modified GDLs (GDL-A′B with uniform double GDBL and GDL-A′C with heterogeneous double GDBLs). In order to evaluate the effect of stacking and structural design on the self-humidification characteristics, some characteristics of the GDLs such as contact angle, resistance, and vapor permeation rate were measured. The electrochemical performances of the fuel cells were also measured at various relative humidity (RH) and stoichiometric ratio (SR) conditions. The results showed that stacking had a negligible effect, whereas the structural design of the GDBL had a significant effect on self-humidification. The self-humidification effect and the cell performance were improved significantly in the structurally modified GDBL. In addition, considering the actual field conditions and the results of the present study, it was concluded that the structural modifications made to the GDBL would

  16. PEM fuel cells for mobile applications. Project part: Membrane development. Final report; PEM-Brennstoffzellen fuer mobile Anwendungen. Teilprojekt: Membranentwicklung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Frank, G

    1999-01-20

    Polymer-Electrolyte-Membrane Fuel Cells (PEMFC) are attractive candidates for next century propulsion systems in passenger cars. The technical feasibility has been demonstrated by several car manufacturers. Today, PEMFC lack economical viability. One of the reasons is the cost of currently used materials, e.g. membranes. This project target towards the development of low cost, non-fluorinated membranes, which fulfil all technical requirements in PEMFC systems. In the frame of this project we were able to successfully develop new membranes based on polyaromatic polymers, which can be produced on a technical scale. These membranes enabled high power densities, exceeding 700 mW/cm{sup 2} at 80 C and their longevity has been demonstrated successfully up to 5,000 hours. Therefore, these membranes have sufficient electrochemical stability for the application in fuel cells. The prices in mass production for these new membranes can get significantly below prices of fluorinated membranes. (orig.) [Deutsch] Polymer-Elektrolyt-Membran-Brennstoffzellen (PEMFC) gelten als aussichtsreiche Kandidaten fuer alternative Fahrzeugantriebe fuer das naechste Jahrzehnt. Die technische Machbarkeit ist bereits mehrfach demonstriert worden. Allerdings sind die Kosten der PEMFC-Systeme noch zu hoch u.a. durch zu hohe Kosten der eingesetzten Materialien, so auch der Membranen. Ziel des Projektes war daher die Entwicklung kostenguenstiger, nichtfluorierter Membranen, die die technischen Anforderungen fuer die Anwendung in der PEM-Brennstoffzelle erfuellen. Im Projekt konnten erfolgreich Membranen auf Basis polyaromatischer Polymere entwickelt werden, die sich auch im technischen Massstab herstellen lassen. Die Membranen ermoeglichen hohe Leistungsdichten groesser 700 mW/cm{sup 2} bei Betriebstemperaturen von 80 C. Die Lebensdauer der Membranen wurde erfolgreich ueber 5.000 Stunden nachgewiesen. Die elektrochemische Stabilitaet der untersuchten Materialien ist damit gegeben. Die Preise dieser

  17. Effect of atomic composition on the compressive strain and electrocatalytic activity of PtCoFe/sulfonated graphene

    International Nuclear Information System (INIS)

    Lohrasbi, Elaheh; Javanbakht, Mehran; Mozaffari, Sayed Ahmad

    2017-01-01

    Highlights: • SO_3H-graphene supported PtFeCo alloy nanoparticles were prepared. • Co:Fe atomic ratio plays important role in the electrocatalytic performance. • PtCoFe/SG with 7:3 Co:Fe atomic ratio is optimized for PEMFCs. • Power density of 530 mW cm"−"2 with 0.1 mg cm"−"2 Pt loading was obtained at 75 °C. - Abstract: The aim of this work is improvement of the stability and durability of sulfonated graphene supported PtCoFe electrocatalyst (PtCoFe/SG) for application in proton exchange membrane fuel cells (PEMFCs). The durability investigation of PtCoFe/SG is evaluated by a repetitive potential cycling test. The compressive strain in the lattice of PtCoFe/SG towards the electrocatalytic oxygen reduction reaction is studied. The synthesized electrocatalysts are examined physically and electrochemically for their structure, morphology and electrocatalytic performance. It is shown that presence of SO_3− groups on the graphene cause better adsorption of PtCoFe nanoparticles on the support and increase stability of electrocatalysts. Also, it is shown that Co:Fe atomic ratio in the synthesized electrocatalysts plays important role in their electrocatalytic performance. In the optimum Co:Fe atomic ratio, the compressive strain goes through the ideal value of the binding energy; further increase in Co/Fe atomic fraction introduces the excessive compressive strain and the activity of electrocatalyst decreases. The electrocatalyst synthesized in the optimum conditions is utilized as cathode in PEMFC. The power density of the PEMFC in low metal loading (0.1 mg cm"−"2 Pt) reaches to a maximum of 530 mW cm"−"2 at 75 °C. It suggests that PtCoFe/SG with 7:3 Co:Fe atomic ratio promises to improve the power density of PEMFCs.

  18. UNA PROPUESTA EVALUATIVA PARA ACTIVIDADES DE EDUCACIÓN AMBIENTAL PARA LA SOSTENIBILIDAD

    Directory of Open Access Journals (Sweden)

    Rosa M. Medir Huerta

    2016-01-01

    Full Text Available El propósito de este artículo es presentar una propuesta evaluativa para ac - tividades de educación ambiental para la sostenibilidad en el ámbito escolar ofrecidas desde entidades externas a la escuela. Para ello, se realiza una eva - luación real de un programa educativo de una administración pública que se orienta al refuerzo del currículo de educación infantil, primaria y secundaria. El objetivo de la evaluación es diagnosticar la presencia, en las actividades estudiadas, de principios clave de la educación ambiental para la sosteni - bilidad identificados por el equipo de investigación a partir de referencias internacionales. La metodología es la investigación evaluativa de programas dentro del paradigma crítico de la investigación educativa y con herramientas de tipo cuantitativo. Se utiliza, básicamente, un cuestionario expresamente diseñado que valora la presencia y la ausencia de los principios establecidos de la educación ambiental para la sostenibilidad. Los resultados nos aportan nuevas informaciones acerca de las fortalezas y las debilidades del desarrollo de actividades de educación ambiental. Se llega a una valoración cuantificada de los principios definidos en tres grupos, según su necesidad de mejora, y se determina que los principios mejor tratados en las actividades son los que se relacionan con los contenidos disciplinares más clásicos, tratados con buenos y distintos métodos didácticos. En cambio, las debilidades detectadas se refieren a aspectos cruciales de la educación ambiental tales como experimentar nuevas sensaciones, aprender a buscar información, pensamiento crítico, sentimiento de pertenencia a un lugar, trabajo en colaboración, adquirir una visión global de la realidad, y reflexionar sobre la vida cotidiana y sobre el futuro deseado.

  19. Récupération du platine contenu dans les piles à combustible basse température par voie hydrométallurgique Platinum Recovery from used PEMFC by hydrometallurgy

    Directory of Open Access Journals (Sweden)

    Vincent Denis

    2013-11-01

    Full Text Available La récupération du platine contenu dans la couche catalytique des piles à combustible est nécessaire pour viabiliser cette technologie vers le secteur industriel. Dans cette étude la voie purement hydrométallurgique a été privilégiée au procédé de récupération pyrométallurgique, évitant la destruction des autres constituants de la pile (membrane, … et limitant la formation de gaz toxique. Le procédé mise en œuvre est constitué d'une étape de lixiviation à partir d'un mélange HCl/HNO3, suivie par la précipitation d'un sel de platine (NH42PtCl6 pouvant soit servir à la synthèse d'un nouveau catalyseur soit à l'obtention de platine métallique. Sur l'ensemble de la chaîne un rendement de récupération de plus de 80 % a pu être obtenu mettant en avant le potentiel de cette stratégie. The recovery of platinum in the catalyst layers of PEMFCs (proton exchange membrane fuel cells is required to allow a transfer in industry. In this study, hydrometallurgical route was preferred to pyrometallurgical process, reducing both the destruction of the other components of the cell (membrane, … and the formation of hazardous gas. In this work, the process includes a leaching step from a diluted aqua regia solution, followed by a precipitation step of platinum under the (NH42PtCl6 form. This salt can be used either for the synthesis of a new catalyst or to obtain a metallic platinum. Considering these steps the recovery efficiency has been found to be over 80 %, which bring out the potential of this strategy.

  20. A study to solve the variability of wind generation through integration of large-scale hydraulic generation; Um estudo para resolver a variabilidade da geracao eolica atraves da integracao em larga escala com geracao hidraulica

    Energy Technology Data Exchange (ETDEWEB)

    Emmerik, Emanuel Leonardus van; Steinberger, Johann Michael; Aredes, Mauricio [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEE/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Eletrica

    2010-07-01

    The optimal deployment of wind generation with the hydro generation is being investigated as a viable option to assist in resolving the constraints coming ahead as a consequence of the tendency of recovery in the Brazilian Amazon basin for expansion of generating facilities. It is in the validity of this research that this work is focused. The value is shown of feasibility studies of using water power generation to offset the variability of wind generation when it is deployed on a large scale. Preliminary results are presented for the variability of wind generation at various cycles, the variability of the availability of hydropower. (author)

  1. Synthesis and characterization of sulfonic acid membranes based on interpenetrating polymer networks for application in fuel cells; Sintese e caracterizacao de membranas sulfonadas baseadas em redes polimericas interpenetrantes para aplicacao em celulas a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Lyzed Toloza; Loureiro, Felipe A.M.; Rocco, Ana Maria [Grupo de Materiais Condutores e Energia, Escola de Quimica, Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)], e-mail: amrocco@eq.ufrj.br; Pereira, Robson Pacheco [Instituto de Ciencias Exatas, Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil)

    2011-07-01

    In the present work, the synthesis and characterization of sulfonic membranes based on interpenetrating polymer networks (IPN). In order to obtain such systems, the diglycidyl ether of bisphenol A (DGEBA) was polymerized in presence of polyethyleneimine (PEI). These membranes were submitted to sulfonation reactions, originating IPN-SO{sub 3}H membranes. The characterization by FTIR evidenced the formation of a Semi-IPN structure, while sulfonation reactions resulted in systems containing -SO{sub 3}H groups covalently bonded to the chains. The membranes exhibited water retention up to 200 degree C, in a temperature range sufficient for application in PEMFC under hydration. (author)

  2. Energy analysis of fuel cell system for commercial greenhouse application – A feasibility study

    International Nuclear Information System (INIS)

    Vadiee, Amir; Yaghoubi, Mahmoud; Sardella, Marco; Farjam, Pardis

    2015-01-01

    Highlights: • Feasibility study of integrating a PEMFC with a commercial greenhouse. • An energy analysis has been performed in order to evaluate the energetic performance of the system. • A sensitivity analysis on the main influencing operating parameters for optimization. - Abstract: The purpose of this paper is to investigate the feasibility of integrating a proton exchange membrane fuel cell (PEMFC) system with a commercial greenhouse and assess the mutual benefits of such integration. The main objective is to recover the low quality waste heat of the PEMFC system in order to meet the thermal energy demand of a commercial greenhouse. In addition the PEMFC covers the some part of the greenhouse electrical demand. In this study an energy analysis has been performed in order to evaluate the energetic performance of the system. To achieve these aims, first, a system model has been developed using TRNSYS. Afterwards, a sensitivity analysis has been carried out varying the main influencing operating parameters in order to evaluate an optimal configuration of the system. In particular the influences of temperature and air stoichiometry have been investigated. The results show that a 3 kW fuel cell system is capable to cover approximately the 25% and 10% of the usual electricity and heat demands of a 1000 m 2 commercial greenhouse during a year, respectively

  3. Effect of induced cross flow on flow pattern and performance of proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Jiao, Kui; Bachman, John; Zhou, Yibo; Park, Jae Wan

    2014-01-01

    Highlights: • 3D numerical works to study the effect of cross flow on the PEMFC performance. • The cross flow ensure more evenly distributed water and oxygen in the CL. • The optimal net power output can be identified by controlling the back pressure. • Results confirm that present design is effective in improving performance. - Abstract: The cross flow in proton exchange membrane fuel cells (PEMFCs) plays an important role in changing the transport pattern and performance. In this study, three-dimensional numerical simulations are carried out to investigate the effect of induced cross flow on the flow pattern and performance of a PEMFC with a previously proposed and experimentally studied novel parallel flow channel design. The numerical results indicate that the liquid water and oxygen become more evenly distributed in the catalyst layer (CL) as the pressure difference between the low-pressure and high-pressure flow channels increases. It has been found that, in the low-pressure channels, the cross flow drives a convective flow from the CL to the flow channel resulting in improved liquid water removal. The optimal net power output can be identified by controlling the back pressure on the high-pressure flow channels. The numerical results confirm that this novel parallel flow channel design is effective in improving PEMFC performance

  4. Numerical investigation of the coupled water and thermal management in PEM fuel cell

    International Nuclear Information System (INIS)

    Cao, Tao-Feng; Lin, Hong; Chen, Li; He, Ya-Ling; Tao, Wen-Quan

    2013-01-01

    Highlights: ► A fully coupled, non-equilibrium, anisotropic PEM fuel cell computational model is developed. ► The coupled water and heat transport processes are numerically investigated. ► Anisotropic property of gas diffusion layer has an effect on local cell performance. ► The boundary temperature greatly affects the cell local temperature and indirectly influences the saturation profile. ► The cathode gas inlet humidity slightly affects the local temperature distribution. - Abstract: Water and thermal managements are the most important issue in the operation and optimization of proton exchange membrane fuel cell (PEMFC). A three-dimensional, two-phase, non-isothermal model of PEMFC is presented in this paper. The model is used to investigate the interaction between water and thermal transport processes, the effects of anisotropic characters of gas diffusion layer, different boundary temperature of flow plate and the effect of gas inlet humidity. By comparing the numerical results of different cases, it is found that maximum cell temperature is higher in the isotropic gas diffusion layer; in contrast, the liquid saturation is lower than other case. Moreover, the boundary temperature greatly affects the temperature distribution in PEMFC, and indirectly influences the water saturation distribution. This indicates that the coupled relationship between water and thermal managements cannot be ignored, and these two processes must be considered simultaneously in the optimization of PEMFC

  5. Iridium-decorated palladium-platinum core-shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell.

    Science.gov (United States)

    Wang, Chen-Hao; Hsu, Hsin-Cheng; Wang, Kai-Ching

    2014-08-01

    Carbon-supported Pt, Pd, Pd-Pt core-shell (Pt(shell)-Pd(core)/C) and Ir-decorated Pd-Pt core-shell (Ir-decorated Pt(shell)-Pd(core)/C) catalysts were synthesized, and their physical properties, electrochemical behaviors, oxygen reduction reaction (ORR) characteristics and proton exchange membrane fuel cell (PEMFC) performances were investigated herein. From the XRD patterns and TEM images, Ir-decorated Pt(shell)-Pd(core)/C has been confirmed that Pt was deposited on the Pd nanoparticle which had the core-shell structure. Ir-decorated Pt(shell)-Pd(core)/C has more positive OH reduction peak than Pt/C, which is beneficial to weaken the binding energy of Pt-OH during the ORR. Thus, Ir-decorated Pt(shell)-Pd(core)/C has higher ORR activity than Pt/C. The maximum power density of H2-O2 PEMFC using Ir-decorated Pt(shell)-Pd(core)/C is 792.2 mW cm(-2) at 70°C, which is 24% higher than that using Pt/C. The single-cell accelerated degradation test of PEMFC using Ir-decorated Pt(shell)-Pd(core)/C shows good durability by the potential cycling of 40,000 cycles. This study concludes that Ir-decorated Pt(shell)-Pd(core)/C has the low Pt content, but it can facilitate the low-cost and high-efficient PEMFC. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. TRABALHAR PARA ESTUDAR / ESTUDAR PARA TRABALHAR: REALIDADE E POSSIBILIDADES

    Directory of Open Access Journals (Sweden)

    Janes Siqueira

    2011-07-01

    Full Text Available O trabalho que apresentamos é parte da pesquisa com os estudantes das licenciaturas e da pedagogia da Universidade de Santa Cruz do Sul-UNISC-RS-Brasil. Este está inserido na linha de pesquisa: educação, trabalho e emancipação. Queremos compreender, à luz do materialismo histórico e dialético e das categorias da crítica da economia política, os significados atribuídos pelos estudantes universitários ao fenômeno trabalho e estudo. É uma pesquisa preferentemente qualitativa de natureza dialética. Para Marx, a essência da realidade humana reside no trabalho, mas a fonte de toda a riqueza está na natureza. Logo, trabalho, natureza e sociedade estão em relação dialética. Trabalho, portanto, é a ideia central articuladora, e natureza e sociedade devem ser estudadas em conexão com o trabalho. Marx trata o trabalho, no modo de produção capitalista, como impedimento ao desenvolvimento humano. Propõe o mesmo como um ato de criação e auto-expressão humana que não deve ter um valor. A compreensão dessa premissa é necessária para que os trabalhadores possam significar e ressignificar o trabalho para além da ideologia dominante. Algumas categorias aparecem como relevantes para a análise: condições de trabalho e de estudo, necessidade de formação, predominância do trabalho sobre o estudo, dificuldade de conciliar tempo de estudo e de trabalho. Na relação com o objeto de estudo, ressaltaremos a crise estrutural do capital, a desregulamentação das leis do trabalho e sua flexibilização e as contradições entre trabalho e estudo bem como quais possibilidades emancipatórias são visualizadas ou sonhadas pelos trabalhadores-estudantes. PALAVRAS-CHAVE: contradições entre trabalho e educação, condições e significados, realidade e possibilidades.

  7. Educación para la sostenibilidad

    Directory of Open Access Journals (Sweden)

    Educadores por la sostenibilidad

    2006-04-01

    Full Text Available La importancia dada por los expertos en sostenibilidad al papel de la educación queda reflejada en el lanzamiento mismo de la Década de la Educación para el Desarrollo Sostenible o, mejor, para un futuro sostenible (2005-2014 a cuyo impulso y desarrollo esta destinado este artículo, así como la página web que la Organización de Estados Iberoamericanos ha habilitado dentro de su portal digital, para la celebración de la Década.

  8. Obtención de ferromanganeso alto carbono y escoria para el desarrollo de materiales para soldar

    Directory of Open Access Journals (Sweden)

    Lorenzo Perdomo-González

    2000-03-01

    Full Text Available En el presente trabajo se realiza un análisis de la posibilidad de empleo de pirolusita en el desarrollo de aleaciones al manganeso y escorias con un sistema de óxidos MnO-SiO2-CaO con características propias para el desarrollo de fundentes para la soldadura automática para arco sumergido (SAAS. A partir de la composición química del mineral de manganeso se realizan los cálculos del proceso de reducción con el empleo de la tecnología sin fundente en presencia de coque como reductor, obteniéndose las adecuadas composiciones y las propiedades de los productos del proceso. Se realiza una corrida experimental de obtención de ferromanganeso con adiciones de dolomita, caolín y fluorita como correctores de la escoria. Se conforma una matriz de fundente para arco sumergido con la escoria y se le evalúan las propiedades tecnológicas de soldadura.

  9. Avaliação das competências de professores de enfermagem para desenvolver programas educativos para adultos

    Directory of Open Access Journals (Sweden)

    Patricia Bover Draganov

    2013-08-01

    Full Text Available Avaliar o desempenho que o enfermeiro docente de enfermagem atribui a si, nas competências para desenvolver programas educativos para adultos, foi objetivo desse estudo descritivo, comparativo, transversal e quantitativo, desenvolvido com 226 docentes enfermeiros de cursos de graduação em enfermagem paulistanos. Os dados foram colhidos por escala de Likert, lançados em planilha Excel® e analisados por estatística descritiva e testes não paramétricos de Wilcoxon e Friedman. A população tinha predominantemente entre 46-55 anos (87/38,49%, eram mulheres (198/87, 61% e mestres (180/79, 65%. Os professores consideraram-se distantes das competências que almejavam alcançar. A menor habilidade esteve em construir desenhos de programas para atender às situações de aprendizagem e a maior, em avaliar programas de ensino. O maior desejo esteve em desenhar programas com formatos criativos e o menor desejo para usar conselhos, comitês e força-tarefa. Concluiuse que desenhar programas educativos para adultos ainda é algo pouco explorado e pouco experenciado por esses docentes.

  10. Caminhos para a gestão integrada do território no Vale do Paraíba de 1950 a 2004

    Directory of Open Access Journals (Sweden)

    José Luiz Ronca Caruso

    2004-01-01

    Full Text Available The Paraíba Valley region and its political-administrative frame. The region and its two phases of Planning: the economic development and the sustainable one. The Paraíba Valley Road System as a policy of the economic planning. The Paraíba Valley Region and its physical conformation: the Paraíba do Sul river basin. The water resources management in the Paraíba do Sul river basin. Two levels of management: the federal and the one of the State. The water resources Planning and its possibilities for a sustainable development of the region, through a comprehensive management

  11. Universidades accesibles para todos

    Directory of Open Access Journals (Sweden)

    Roxana Stupp Kupiec

    2001-01-01

    Full Text Available Este trabajo pretende hacer conciencia sobrelos factores que inciden en la construcción colectiva deuniversidades dispuestas a innovar y transformar suideología, sus políticas, el currículum, los servicios estu-diantiles, la infraestructura física y administrativa y lasestrategias de comunicación e información, bajo el para-digma de la accesibilidad en el entorno. Se hace referen-cia al marco legal internacional y nacional que orientalas acciones que deben planificarse e implementarse enlas instituciones de Educación Superior.En la construcción de universidades accesibles para to-dos se requiere de un cambio en la concepción curricu-lar. Se analizan conceptos como la flexibilidad en la for-mación y el acceso a los planes de estudio para respondera las necesidades educativas de todos los estudiantes. Para promover estas transformaciones se proponen prin-cipios y prácticas tales como la interdisciplinareidad y lainclusión del tema de la discapacidad en todas las carre-ras. Además, se presentan ejemplos de aplicación en dife-rentes áreas del perfil profesional, en la formación deldocente universitario y en actividades de proyección so-cial, vida estudiantil e investigación. En el ámbito estu-diantil, se describen algunos servicios y procesos que sehan desarrollado en la Universidad de Costa Rica

  12. Propuesta para el cálculo del Índice Dm para la validez de los ítemes

    OpenAIRE

    Dominguez Lara, Sergio

    2013-01-01

    Se presenta un programa en formato MS Excel para calcular el índice Dm para la validez de los ítemes. La validez es un proceso de acumulación de pruebas para apoyar la interpretación y el uso de las puntuaciones de los tests psicológicos, siendo las relaciones de los puntajes con otras variables externas una importante fuente de validación. Una variante es la llamada validez relacionada al criterio, en la cual se espera una correlación significativa con aquellos criterios externos que son teó...

  13. 35-We polymer electrolyte membrane fuel cell system for notebook computer using a compact fuel processor

    Science.gov (United States)

    Son, In-Hyuk; Shin, Woo-Cheol; Lee, Yong-Kul; Lee, Sung-Chul; Ahn, Jin-Gu; Han, Sang-Il; kweon, Ho-Jin; Kim, Ju-Yong; Kim, Moon-Chan; Park, Jun-Yong

    A polymer electrolyte membrane fuel cell (PEMFC) system is developed to power a notebook computer. The system consists of a compact methanol-reforming system with a CO preferential oxidation unit, a 16-cell PEMFC stack, and a control unit for the management of the system with a d.c.-d.c. converter. The compact fuel-processor system (260 cm 3) generates about 1.2 L min -1 of reformate, which corresponds to 35 We, with a low CO concentration (notebook computers.

  14. Investigation of water distribution in proton exchange membrane fuel cells via Terahertz imaging

    International Nuclear Information System (INIS)

    Thamboon, P.; Buaphad, P.; Thongbai, C.; Saisud, J.; Kusoljariyakul, K.; Rhodes, M.W.; Vilaithong, T.

    2011-01-01

    Coherent transition radiation in a THz regime generated from a femtosecond electron bunch is explored for its potential use in imaging applications. Due to water sensitivity, the THz imaging experiment is performed on a proton exchange membrane fuel cell (PEMFC) to assess the ability to quantify water in the flow field of the cell. In this investigation, the PEMFC design and the experimental setup for the THz imaging is described. The results of the THz images in the flow field are also discussed.

  15. Educación para el Ocio: Ha llegado la hora de un nuevo objetivo para una vieja idea.

    Directory of Open Access Journals (Sweden)

    Susan Hutchinson

    2012-01-01

    Full Text Available La Educación para el Ocio nos sitúa ante una vieja idea, que está siendo examinada con renovado vigor en Canadá. Profesionales e investigadores de diversas disciplinas (por ejemplo, en el ámbito de Salud, la Justicia, la Educación o la Recreación reconocen, cada vez más, que son muchas las personas que pueden beneficiarse del ocio y de las oportunidades de recreación en sus comunidades, aún cuando son bastantes las no pueden hacerlo porque carecen de alfabetización en ocio. Esto es, de los conocimientos, habilidades y confianza que se necesitan para darle un significado personal, que incida positivamente en su bienestar y calidad de vida. La Educación para el Ocio es un medio clave para mejorar la alfabetización en ocio. El texto presenta un modelo de educación para el ocio desarrollado por la Dra. Brenda Robertson, argumentando cómo y por qué la Educación para el Ocio es necesaria para abordar la salud mental y el bienestar de las personas que sufren marginación en sus comunidades. Complementariamente se presentan algunas recomendaciones para avanzar esta Educación, como un componente fundamental de la agenda nacional para la recreación en Canadá.--------------------------------------------------------------------Leisure education is an old idea that is being examined with renewed vigour in Canada. Practitioners and researchers from various disciplines (e.g., health, justice, education, recreation are recognising anew that many people who could benefit from leisure or recreation opportunities in their communities are unable to do so because they lack leisure literacy. Leisure literacy refers to the knowledge, skills and confidence to engage in personally meaningful, health-enhancing leisure. Leisure education is a key means to enhance leisure literacy. The paper presents a model of leisure education developed by Dr. Brenda Robertson and argues for how and why leisure education is needed to address the mental health and well

  16. O efeito trabalhador adicional para filhos no Brasil

    Directory of Open Access Journals (Sweden)

    Elzira Lúcia de Oliveira

    2014-06-01

    Full Text Available O objetivo deste trabalho é testar a hipótese da existência do efeito trabalhador adicional para filhos no Brasil, procurando identificar se a situação de desemprego do chefe de família fará com que algum membro da família, cuja condição seja filho, transite para a População Economicamente Ativa - PEA. A base de dados utilizada foi a Pesquisa Mensal de Emprego - PME realizada pelo IBGE, que permite a construção de painéis para análise longitudinal de dados. A hipótese foi testada para pelo menos um filho com idade de 10 a 18 anos, entre 2002 e 2013, para as regiões metropolitanas de Belo Horizonte, Salvador, Porto Alegre, São Paulo, Rio de Janeiro e Recife, que compõem a área de abrangência da PME. Este trabalho admite a existência de diferencial por sexo do chefe para o efeito trabalhador adicional de filhos de 10 a 18 anos. Os resultados mostraram haver um efeito positivo maior para chefes homens do que para chefes mulheres, sendo que a variável de transição do filho para a atividade não apresentou significância estatística que permitisse assumir a existência do efeito. Corroborou-se a hipótese da existência de diferencial por sexo, contudo no sentido oposto ao da hipótese assumida.

  17. Biocomercio: una alternativa para el desarrollo sostenible

    Directory of Open Access Journals (Sweden)

    Carlos Murillo R.

    2008-01-01

    Full Text Available El desarrollo sostenible en países ricos en biodiversidad dependerá de la capacidad de los gobiernos de implementar los arreglos institucionales necesarios para conciliar la preservación de los recursos naturales con el uso de los mismos para la producción de bienes y servicios que puedan potenciar el crecimiento económico y un mayor bienestar para las comunidades locales donde estos recursos se encuentren. Este es el objetivo de la Iniciativa de Biocomercio que ha venido impulsando la Conferencia de Naciones Unidas para el Comercio y el Desarrollo (UNCTAD en distintos países de Latinoamérica. En el tanto estos principios y los establecidos en el CDB se puedan viabilizar e inspiren los distintos Programas Nacionales de Biocomercio en los países de la región, parecería no haber dudas de que la Iniciativa abre nuevas puertas para el uso, aprovechamiento y desarrollo sostenible de los mismos.

  18. ANÁLISE, MODELAGEM E IMPRESSÃO 3D DE UM FRAME PARA VANTs DO TIPO QUADRÍCOPTEROS PARA VOOS EM AMBIENTE INDOOR

    Directory of Open Access Journals (Sweden)

    Rafael Rocha Gomes

    2017-01-01

    Full Text Available O foco do projeto de pesquisa foi analisar, modelar e construir utilizando uma impressora 3D, um frame de um Veículo Aéreo Não Tripulado (VANT para voos em ambiente indoor. Esta aeronave será usada para experimentos laboratoriais, que exijam características especiais para ambientes indoor e de pesquisa, tais como, ser compacto, leve e uma estrutura que minimize os riscos aos operadores, pois dividirá espaço com pessoas. A motivação desta pesquisa se deu pelo fato dos frames disponíveis no mercado serem voltados para voos outdoor, como por exemplo, os utilizados para monitoramento. Com o intuito de proporcionar uma solução de aeronave para espaço laboratorial indoor, a proposta deste trabalho foi de modelar e imprimir em 3D um protótipo de frame que atenda todos os requisitos necessários para este tipo de voo.

  19. Para una Mejor Comprensión del Desarrollo: Análisis conceptual, lógica para su abordaje e instrumentos para su medición

    Directory of Open Access Journals (Sweden)

    Héctor Cárcamo

    2006-01-01

    cross nacional para la realización de estudios vinculados al desarrollo. Se plantea una revisión de conceptos fundamentales como el de desarrollo y la necesidad de la equivalencia funcional. El documento continúa con una reflexión guiada desde la noción de desarrollo social; asumiendo críticamente que el desarrollo se ha plasmado como un intento por lograr una radiografía del todo que ha olvidado la integración de sus partes constituyentes, negando de esta manera la diversidad como condición esencial para dar sentido a la idea de una visión integradora. Finalmente se realiza una revisión de CASEN como instrumento para medir el desarrollo social en Chile.

  20. GOOGLE DRIVE: POTENCIALIDADES PARA O DESIGN DE MATERIAL EDUCACIONAL DIGITAL (MED PARA ENSINO DE LÍNGUAS

    Directory of Open Access Journals (Sweden)

    Rosinda de Castro Guerra RAMOS

    2017-07-01

    Full Text Available Este trabalho tem como objetivo apresentar uma experiência sobre como o Google Drive pode ser usado para o desenho de MED (Material Educacional Digital para o ensino-aprendizagem de línguas, devido ao crescente uso das TDICs (Tecnologias Digitais de Informação e Comunicação na área de educação e aos desafios que o design de materiais educacionais para o ambiente digital nos lançam.  Para apresentar nossa experiência, faremos uma discussão teórica sobre os conceitos de desenvolvimento de material didático (TOMLINSON, 2003; RAMOS, 2009, de material educacional digital –MED – (BEHAR, 2009, multimodalidade (ROJO e BARBOSA, 2015, a lacuna existente em relação ao  letramento digital na formação de professores (LEFFA, 2013, os níveis/tipos  de interação em ambiente digital (HIRUMI, 2013 e sua relação na coconstrução de novos conhecimentos (VIGOTSKY, 1989, 1998; OLIVEIRA, 1997; BRASIL, 1998. Em seguida, descreveremos o Google Drive e as funcionalidades dos aplicativos de produtividade Google Documentos, Planilhas, Apresentações e Formulários. Finalizaremos com considerações sobre essa experiência e suas contribuições para a área de formação de professores de línguas.

  1. Factores de riesgo para el neonato pequeño para la edad gestacional en un hospital de Lima, Perú

    Directory of Open Access Journals (Sweden)

    J. Eduardo Tejeda-Mariaca

    Full Text Available Objetivos. Identificar factores de riesgo para neonatos a término pequeños para la edad gestacional. Materiales y métodos. Cohorte retrospectiva que utilizó datos del Sistema Informático Materno Perinatal del Hospital María Auxiliadora de Lima, del período 2000 a 2010. Se evaluó la edad materna, paridad, nivel educativo, estado civil, índice de masa corporal pregestacional, número de controles prenatales, presencia de patologías como preeclampsia, eclampsia, infección urinaria y diabetes gestacional como factores de riesgo en pequeños para edad gestacional. El peso para la edad gestacional fue calculado sobre la base de percentiles peruanos. Se calcularon los riesgos relativos crudos (RR y ajustados (RRa con sus intervalos de confianza al 95% usando modelos lineales generalizados log binomial. Resultados. Se incluyeron 64 670 gestantes. La incidencia de pequeños para la edad gestacional fue 7,2%. La preeclampsia (RRa 2,0; IC 95%: 1,86-2,15, eclampsia (RRa 3,22; IC 95%: 2,38-4,35, bajo peso materno (RRa 1,38; IC 95%: 1,23-1,54, nuliparidad (RRa 1,32; IC 95%: 1,23-1,42, edad ≥35 años (RRa 1,16; IC 95%: 1,04-1,29, tener controles prenatales de 0 a 2 (RRa 1,43; IC 95%: 1,32-1,55 y 3 a 5 (RRa 1,22; IC 95%: 1,14-1,32 fueron factores de riesgo para ser pequeños para la edad gestacional. Conclusiones. Es necesario identificar a las gestantes con factores de riesgo como los encontrados para disminuir la condición de pequeños para la edad gestacional. Se debe actuar poniendo énfasis en factores modificables, tales como la frecuencia de sus controles prenatales

  2. Conductor polymeric membranes with potential for application in PEM type fuel cells; Membranas polimericas condutoras com potencialidades para aplicacao em celulas a combustivel do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Brioude, Michel de Meireles; Sodre, Livia Farias; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)

    2006-07-01

    In this work two series of membranes were prepared; they were based on hybrid organic-inorganic or composite materials and presented potentiality for application in Proton Exchange Membrane Fuel Cell, PEMFC. The polymeric phase was constituted of poly(dimethylsiloxane), PDMS, crosslinked with tetra ethoxysilane, TEOS, with a 70%/30% ratio. Phosphotungstic acid (PWA) or the sodium monododecylsulphate (MDS), as proton conductors, were added to the inorganic network, close to the gel point; the mixtures were transferred to a cast. The films were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The membranes showed good properties, as flexibility, thermal and mechanical stability with potentiality to be used as conducting membranes in technological applications. (author)

  3. Ciclo Hápticos: Para Quinteto de Sopros

    Directory of Open Access Journals (Sweden)

    Jorge Luiz de Lima Santos

    2016-06-01

    Full Text Available Memorial e partitura de Ciclo Hápticos, escrita em 2014 para quinteto de sopros. O memorial descreve brevemente as ferramentas metodológicas empregadas para o planejamento e criação da obra. De um lado, para produção do material melódico-harmônico foi empregado o Sistema-Gr de composição musical, desenvolvido por Carlos Almada (2014. Do outro lado, para organização formal, utilizamos o software Partitions - que faz parte do conjunto de programas do Parsemat, elaborado por Pauxy Gentil-Nunes (2009 – o qual informa o conjunto total de possibilidades de partições de um dado número.

  4. Routes to a commercially viable PEM fuel cell stack

    Energy Technology Data Exchange (ETDEWEB)

    Newton, J.; Foster, S.E.; Hodgson, D.; Marrett, A.

    2002-07-01

    This report describes the results of a project to design and build a 10 kW{sub e} proton exchange membrane fuel cell (PEMFC) stack, including membrane electrode assemblies (MEAs), bipolar plates and stack hardware. The aim was to prove the design concept and to demonstrate functionality by operating the stack at >1 kW{sub e}/L and 500 W/kg for 200 hours operation. The project was extended to include the assembly and testing of two additional 1 kW{sub e} PEMFC stacks based on coated metal components. Low equivalent weight perfluorinated ionomer ion exchange membranes were prepared and were found to give a superior electrochemical performance to commercial materials. A technique to etch various stainless steel grades and control processes was successfully developed and optimised. Coatings for stainless steel and titanium were successfully developed and met the required performance criteria. All PEMFC stack components were selected and designed to enable subsequent commercial manufacture.

  5. Water droplet dynamic behavior during removal from a proton exchange membrane fuel cell gas diffusion layer by Lattice-Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Molaeimanesh, Golamreza; Akbari, Mohammad Hadi [Shiraz University, Shiraz (Iran, Islamic Republic of)

    2014-04-15

    A major challenge in the application of proton exchange membrane fuel cells (PEMFCs) is water management, with the flooding of electrodes as the main issue. The Lattice-Boltzmann method (LBM) is a relatively new technique that is superior in modeling the dynamic interface of multiphase fluid flow in complex microstructures such as non-homogeneous and anisotropic porous media of PEMFC electrodes. In this study, the dynamic behavior of a water droplet during removal from gas diffusion layer (GDL) of a PEMFC electrode with interdigitated flow field is simulated using LBM. The effects of GDL wettability and its spanwise and transverse gradients on the removal process are investigated. The results demonstrate great influence of wettability and its spanwise and transverse gradients on the dynamic behavior of droplets during the removal process. Although increasing the hydrophobicity of GDL results in better droplet removal, its increase beyond a critical value does not show a significant effect.

  6. Platinum redispersion on metal oxides in low temperature fuel cells.

    Science.gov (United States)

    Tripković, Vladimir; Cerri, Isotta; Nagami, Tetsuo; Bligaard, Thomas; Rossmeisl, Jan

    2013-03-07

    We have analyzed the aptitude of several metal oxide supports (TiO(2), SnO(2), NbO(2), ZrO(2), SiO(2), Ta(2)O(5) and Nb(2)O(5)) to redisperse platinum under electrochemical conditions pertinent to the Proton Exchange Membrane Fuel Cell (PEMFC) cathode. The redispersion on oxide supports in air has been studied in detail; however, due to different operating conditions it is not straightforward to link the chemical and the electrochemical environment. The largest differences reflect in (1) the oxidation state of the surface (the oxygen species coverage), (2) temperature and (3) the possibility of platinum dissolution at high potentials and the interference of redispersion with normal working potential of the PEMFC cathode. We have calculated the PtO(x) (x = 0, 1, 2) adsorption energies on different metal oxides' surface terminations as well as inside the metal oxides' bulk, and we have concluded that NbO(2) might be a good support for platinum redispersion at PEMFC cathodes.

  7. Electrocatalytic activity mapping of model fuel cell catalyst films using scanning electrochemical microscopy

    International Nuclear Information System (INIS)

    Nicholson, P.G.; Zhou, S.; Hinds, G.; Wain, A.J.; Turnbull, A.

    2009-01-01

    Scanning electrochemical microscopy has been employed to spatially map the electrocatalytic activity of model proton exchange membrane fuel cell (PEMFC) catalyst films towards the hydrogen oxidation reaction (the PEMFC anode reaction). The catalyst films were composed of platinum-loaded carbon nanoparticles, similar to those typically used in PEMFCs. The electrochemical characterisation was correlated with a detailed physical characterisation using dynamic light scattering, transmission electron microscopy and field-emission scanning electron microscopy. The nanoparticles were found to be reasonably mono-dispersed, with a tendency to agglomerate into porous bead-type structures when spun-cast. The number of carbon nanoparticles with little or no platinum was surprisingly higher than would be expected based on the platinum-carbon mass ratio. Furthermore, the platinum-rich carbon particles tended to agglomerate and the clusters formed were non-uniformly distributed. This morphology was reflected in a high degree of heterogeneity in the film activity towards the hydrogen oxidation reaction.

  8. Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

    Science.gov (United States)

    Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf; Cleemann, Lars N.; Li, Qingfeng

    2018-01-01

    Phosphoric acid is the common electrolyte for high-temperature polymer electrolyte fuel cells (HT-PEMFCs) that have advantages such as enhanced CO tolerance and simplified heat and water management. The currently used rotating disk electrode technique is limited to tests in dilute solutions at low temperatures and hence is not suitable for catalyst evaluation for HT-PEMFCs. In this study, we have designed and constructed a half-cell setup to measure the intrinsic activities of catalysts towards the oxygen reduction reaction (ORR) in conditions close to HT-PEMFC cathodes. By optimization of the hydrophobic characteristics of electrodes and the catalyst layer thickness, ORR activities of typical Pt/C catalysts are successfully measured in concentrated phosphoric acid at temperatures above 100 °C. In terms of mass-specific activities, the catalyst exhibits about two times higher activity in the half-cell electrode than that observed in fuel cells, indicating the feasibility of the technique as well as the potential for further improvement of fuel cell electrode performance.

  9. Sliding-Mode Control of PEM Fuel Cells

    CERN Document Server

    Kunusch, Cristian; Mayosky, Miguel

    2012-01-01

    Recent advances in catalysis technologies and new materials make fuel cells an economically appealing and clean energy source with massive market potential in portable devices, home power generation and the automotive industry. Among the more promising fuel-cell technologies are proton exchange membrane fuel cells (PEMFCs). Sliding-Mode Control of PEM Fuel Cells demonstrates the application of higher-order sliding-mode control to PEMFC dynamics. Fuel-cell dynamics are often highly nonlinear and the text shows the advantages of sliding modes in terms of robustness to external disturbance, modelling error and system-parametric disturbance using higher-order control to reduce chattering. Divided into two parts, the book first introduces the theory of fuel cells and sliding-mode control. It begins by contextualising PEMFCs both in terms of their development and within the hydrogen economy and today’s energy production situation as a whole. The reader is then guided through a discussion of fuel-cell operation pr...

  10. Hydrogen from methanol for fuel cells in mobile systems: development of a compact reformer

    Energy Technology Data Exchange (ETDEWEB)

    Hoehlein, B [Forschungszentrum Juelich GmbH (Germany); Boe, M [H. Topsoee A/S, Lyngby (Denmark); Boegild-Hansen, J [H. Topsoee A/S, Lyngby (Denmark); Broeckerhoff, P [Forschungszentrum Juelich GmbH (Germany); Colsman, G [Forschungszentrum Juelich GmbH (Germany); Emonts, B [Forschungszentrum Juelich GmbH (Germany); Menzer, R [Forschungszentrum Juelich GmbH (Germany); Riedel, E

    1996-07-01

    On-board generation of hydrogen from methanol with a reformer in connection with the use of a proton-exchange membrane fuel cell (PEMFC) is an attractive option for a passenger car drive. Special considerations are required to obtain low weight and volume. Furthermore, the PEMFC of today cannot tolerate more than 10 ppm of carbon monoxide in the fuel. Therefore a gas conditioning step is needed after the methanol reformer. Our main research activities focus on the conceptual design of a drive system for a passenger car with methanol reformer and PEMFC: Engineering studies with regard to different aspects of this design including reformer, catalytic burner, gas conditioning, balances of the fuel cycles and basic design of a compact methanol reformer. The work described here was carried out within the framework of a JOULE II project of the European Union (1993-1995). Extensive experimental studies have been carried out at the Forschungszentrum Juelich GmbH (KFA) in Germany and at Haldor Topsoee A/S in Denmark. (orig.)

  11. Novel membranes for proton exchange membrane fuel cell operation above 120°C. Final report for period October 1, 1998 to December 31, 1999

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, Supramaniam [Princeton Univ., NJ (United States); Lee, Seung-Jae [Princeton Univ., NJ (United States); Costamagna, Paola [Princeton Univ., NJ (United States); Yang, Christopher [Princeton Univ., NJ (United States); Adjemian, Kevork [Princeton Univ., NJ (United States); Bocarsly, Andrew [Princeton Univ., NJ (United States); Ogden, Joan M. [Princeton Univ., NJ (United States); Benziger, Jay [Princeton Univ., NJ (United States)

    2000-05-01

    In this project we investigated the experimental performance of three new classes of membranes, composites of perfluorosulfonic acid polymers with heteropolyacides, hydrated oxides and fast proton conducting glasses, which are promising candidates as electrolytes for proton exchange membrane fuel cells (PEMFCs), capable of operation at temperatures above 120°C. The motivations for PEMFC's operation at this temperature are to: 1) minimize the CO poisoning problem (adsorption of CO onto the platinum catalyst is greatly reduced at these temperatures), 2) find better solutions for the water and thermal management problems in proton exchange membrane fuel cells, 3) find potentially lower cost materials for proton exchange membranes. We prepared and characterized a variety of novel membrane materials. The most promising of these have been evaluated for performance in a single, small area (5cm2) fuel cell run on hydrogen and oxygen. Our results establish the technical feasibility of PEMFC operation above 120°C.

  12. Palladium-mediated conversion of para-aminoarylboronic esters into para-aminoaryl- 11C-methanes

    DEFF Research Database (Denmark)

    Andersen, Valdemar Lykke; Herth, Matthias Manfred; Lehel, Szabolcs

    2013-01-01

    of free amines. Aryl boronic esters containing primary, secondary, and tertiary amines were successfully converted into corresponding labeled methyl derivatives in suf¿cient radiochemical yield to apply this method for tracer development. This procedure was applied to the labeling of CIMBI-712......Cross-couplings are an alternative to conventional 11C-methylations which are generally employed in PET tracer synthesis. Therefore, we set out to develop a general procedure for the synthesis of para-11CH3 labeled aromatic amines from the corresponding para-aminoarylboronic esters in the presence...

  13. Sistema de autenticidad para aplicaciones de análisis de eventos para seguridad.

    OpenAIRE

    ESCAMILLA PARDO, TONI

    2017-01-01

    [ES] En este proyecto se afronta la creación de un sistema distribuido capaz de garantizar, en aplicaciones empleadas para el análisis de eventos de seguridad, la autenticidad de los datos transmitidos entre el host cliente y servidor con el fin de asegurar la integridad de los mismos en la transmisión entre ambas partes, así como evitar la posible alteración en el destino. Para ello, se utilizará la tecnología blockchain a modo de base de datos en la que se almacenen los hashe...

  14. Para uma abordagem virtuosa do Jornalismo

    Directory of Open Access Journals (Sweden)

    Rogério Christofoletti

    2012-06-01

    Full Text Available As últimas décadas têm favorecido o crescimento do interesse e dos estudos sobre a ética jornalística. No Brasil e em outras praças, as abordagens deste tema têm sido na maioria das vezes por um caráter deontológico ou utilitarista. Neste artigo, chamamos a atenção para uma perspectiva que privilegie as virtudes como pontos de partida para os debates acerca das condutas dos profissionais. Uma ética das virtudes remete a Aristóteles e aos estoicos, mas vem sendo retomada por autores mais contemporâneos, como Macintyre e Comte-Sponville, entre outros. No jornalismo, esta abordagem não é definitiva ou totalizante, mas contribui para uma compreensão mais ampla da discussão, chamando inclusive a atenção para recomendações éticas úteis, práticas e atuais.

  15. Educación para la Salud: espacio curricular optativo para los estudiantes de la carrera de Medicina

    OpenAIRE

    Susacasa, Sandra; Candreva, Anna; Cerasa, Silvana; Azanza, Marisa

    2016-01-01

    La educación para la salud adquiere relevancia en los programas institucionales internacionales. Estos se orientan a promover un mayor nivel de salud en la población. Sin embargo, las problemáticas vinculadas al campo de la educación para la salud, de acuerdo con los informes epidemiológicos, no están mejorando. Aún más, la situación se vuelve más crítica. En nuestro país las demandas sociales expresan la urgente necesidad de instalar la Educación para la Salud en espacios educativos y de sal...

  16. Modelo para la implementación de controles internos para empresas constructoras.

    OpenAIRE

    Choez Chiquito, Wilton Antonio

    2015-01-01

    La presente investigación se refiere al tema Metodología para la implementación de nuevos métodos de Control para las empresas de construcción en el Ecuador. Donde las características principales de este sector ha sido su rápido crecimiento en las últimas dos décadas, con un alto número de trabajadores de obras con bajo o ningún nivel de educación, falta de compromiso por parte de los empleados de obra por el alto nivel de rotación que puede existir debido a que las construcciones son por per...

  17. ELEMENTOS PARA LA CONSTRUCION DE UN PERFIL PARA EL GERENTE SOCIAL EN UN ENTORNO GLOBALIZADO

    Directory of Open Access Journals (Sweden)

    Antonio Bastidas Unigarro

    2009-07-01

    Full Text Available El perfil del gerente social adecuado para enfrentar los retos del mundo globalizado se ha estructurado a partir de cuatro requerimientos fundamentales: los conocimientos, la experiencia, las habilidades y las actitudes, los cuales se analizan como competencias indispensables para administrar la problemática compleja, llena de incertidumbres y desafíos del nuevo milenio. La propuesta para la construcción de un perfil de este gerente parte de considerar tres tipos de competencias: las funcionales, las comportamentales y los requisitos de estudio y experiencia. Su construcción parte del análisis de la Gerencia Social en el estado neoliberal, escenario, que reclama la formación de gerentes sociales comprometidos en la construcción de una sociedad mas justa, incluyente, participativa, democrática y solidaria.

  18. The generation of electric power in a model of endogenous development: possible solutions for isolated communities in the Amazonas State, Brazil; A geracao de energia eletrica em um modelo de desenvolvimento endogeno: possiveis solucoes para as comunidades isoladas do interior do estado do Amazonas

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Andre Frazao; Cavaliero, Carla Kazue Nakao [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica

    2006-07-01

    This work was developed to fit the generation of electric energy for the isolated communities of the interior of the Amazonas State in a context of endogenous development. A regional development is proposed, with the inclusion of the generation of electric energy for these communities in a context of development, rather than the isolated form proposed in the federal government electrification program of 'Luz Para Todos' (Light For All). (author)

  19. Lowering the platinum loading of high temperature polymer electrolyte membrane fuel cells with acid doped polybenzimidazole membranes

    DEFF Research Database (Denmark)

    Fernandez, Santiago Martin; Li, Qingfeng; Jensen, Jens Oluf

    2015-01-01

    Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer was establ......Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer...

  20. Platinum Porous Electrodes for Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    Fuel cell energy bears the merits of renewability, cleanness and high efficiency. Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most promising candidates as the power source in the near future. A fine management of different transports and electrochemical reactions in PEM fuel cells...... to a genuine picture of a working PEM fuel cell catalyst layer. These, in turn, enrich the knowledge of Three-Phase-Boundary, provide efficient tool for the electrode selection and eventually will contribute the advancement of PEMFC technology....

  1. Nuevo lenguaje para un nuevo medio

    Directory of Open Access Journals (Sweden)

    Inma Martín Herrera

    2014-12-01

    Full Text Available El concepto tradicional de comunicación unidereccional se ha roto para convertirse en comunicación pluridireccional que permitirá la retroalimentación informativa. Las nuevas formas de redactar, contar diseñar y presentar la información en Internet exige nuevos hábitos de lectura por parte de la audiencia. El lector deberá tomar conciencia de que está frente a un medio diferente con el que debe familiarizarse para hacer uso correcto del soporte digital, se informará adecuadamente para disfrutar de las ventajas del innovador medio, conocido como Periodismo de servicios o Nuevo Periodismo.

  2. “Libros para niñas y libros para niños”: Presencia de estereotipos de género en una colección de libros para dibujar

    Directory of Open Access Journals (Sweden)

    Yolanda Cabrera García-Ochoa

    2014-06-01

    Full Text Available Los aprendizajes que se producen a partir de las propuestas imaginarias y simbólicas en los materiales didácticos pueden contener elementos sexistas. El objetivo del estudio consiste en determinar, a través de un análisis de contenido, si la colección de libros para dibujar “Doodle para niñas” y “Doodle para niños” representa roles estereotipados de género en sus imágenes y en el texto escrito. Tanto a nivel de representación gráfica como escrita, ambos libros utilizan roles estereotipados sobre todo en detrimento de la mujer. Aunque el sistema educativo español señala hace años un modelo igualitario para eliminar la discriminación, los avances conseguidos desde un prisma constitucional y legal, van muy por delante de unos sistemas culturales y sociales que apenas han evolucionado.

  3. Plan de mercadeo para una promotora de eventos corporativos

    OpenAIRE

    Burbano Zhindon, Andrea Cristina; Chavez Lopez, Maria Cecilia; Orlando Haro, Sofia Pierina; Miranda, Jorge Luis

    2009-01-01

    Este proyecto presenta una alternativa para todas aquellas empresas que realizan eventos frecuentemente, ofreciéndoles un servicio personalizado para la coordinación de cada uno de los detalles que conlleva la organización de un evento. El objetivo fundamental de este estudio es desarrollar un plan de mercadeo para el servicio antes mencionado, aplicando los principios del marketing para su correcta implementación.

  4. Agricultura familiar para el desarrollo rural incluyente

    Directory of Open Access Journals (Sweden)

    Laksmi Reddiar Krishnamurthy

    2017-04-01

    Full Text Available Las comunidades indígenas Mayas de la península de Yucatán han practicado la antigua tradición de agricultura familiar, en particular los huertos caseros, para garantizar su seguridad alimentaria. Con el objetivo de mejorar la práctica tradicional considerando paradigmas de la ciencia moderna, por una parte, se colectaron datos para definir la complejidad estructural y diversidad funcional a partir de 20 huertos familiares en cinco comunidades: X - Maben, X - Pichil, X - Yatil, San José II y Melchor Ocampo; y por otra, se organizaron grupos de discusión para dilucidar la estrategia de gestión practicada por las comunidades nativas. Los resultados mostraron que los huertos son manejados principalmente por las mujeres. También mostraron que el propósito principal del crecimiento y mantenimiento de los huertos familiares es garantizar la producción de alimentos nutritivos durante todo el año. Y, por último que los huertos caseros también sirven para propósitos secundarios tales como la provisión de productos y servicios para la medicina tradicional. El estudio sugiere que se debe de promover e invertir en huertos caseros para mejorar las estrategias de desarrollo incluyente en ambientes socio-culturales y biofísicos similares.

  5. Patrones de diseño para mejorar la accesibilidad y uso de aplicaciones sociales para adultos mayores

    Directory of Open Access Journals (Sweden)

    Huizilopoztli Luna García

    2015-07-01

    Full Text Available El objetivo de este artículo fue proponer una colección no exhaustiva de 36 patrones para el diseño de interacciones en aplicaciones sociales para adultos mayores. La propuesta representa un punto de partida confiable para facilitar, a diseñadores/desarrolladores, la integración de usabilidad en las interfaces de estas tecnologías con el fin de fomentar su aceptación, uso y adopción entre los adultos mayores. Esta propuesta se basa en esfuerzos previos comúnmente expresados como criterios y guías de diseño para definir los posibles problemas de usabilidad en este tipo de interfaces, y se concentra en reforzar estos enfoques mediante la integración de una mayor descripción de tales anomalías y alternativas de solución bajo una estructura de patrones útil para los diseñadores/desarrolladores. Se realizó un estudio de usabilidad con la técnica «evaluación heurística» (comúnmente utilizada en interacción hombre-máquina para obtener la percepción de los usuarios sobre un diseño particular. El trabajo se llevó a cabo desde dos perspectivas: el punto de vista de expertos técnicos y la percepción de un grupo social de adultos mayores. Los resultados reflejaron que los patrones propuestos propician la creación de interfaces bien diseñadas capaces de ofrecer una mejor experiencia de uso y promueven un impacto positivo en la calidad de vida de los adultos mayores.

  6. Alimentos balanceados para perros en Costa Rica

    Directory of Open Access Journals (Sweden)

    Ruth Vargas

    2001-01-01

    Full Text Available Diagnóstico de la comercialización de alimentos balanceados para perros en Costa Rica. Para ampliar los reportes oficiales de la comercialización de alimentos para perros se creó una base de datos que incluyó cantidad, costo, empaque y formulación durante el período 1998 a agosto del 2000. De 1995 a 1998 y de 1996 a 1999 la producción nacional incrementó un 90,4% y la importación un 42,56% respectivamente, ocupando los alimentos nacionales un 72% del tonelaje y un 70% del valor en dólares americanos. No fue posible determinar cuál es el empaque más comercializado, pero si que los alimentos extrusados son los que ocupan el primer lugar y que los alimentos recomendados para cachorros y adultos son los que más se comercializan. La ausencia de datos en las declaraciones sugiere la necesidad de incrementar el control en las mismas en caso de requerirse un estudio de mercado, ya que contrariamente a esta situación el mayor número de garantías inscritas corresponden separadamente para las fases de cachorros y adultos. Merece también atención que las garantías indican mayores porcentajes de proteína cruda que los recomendados por la AAFCO y que al menos 36 fórmulas son recomendadas para estados sanitarios específicos (p.e. para perros con problemas de alergias, cálculos renales, pérdidas de pelo, etc. sin que oficialmente se encuentre registrada ninguna fórmula medicada

  7. Design of radiofrequency coils for NMR imaging; Desenvolvimento de bobinas de radiofrequencia para geracao de imagens por ressonancia magnetica nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Maria Angelica

    1988-07-01

    In this work we describe and analyse different types of radiofrequency coils for NMR Imaging. Our system operates with a superconducting magnet, 22.5 cm bore, at 2.0 Tesla (85 MHz, resonant frequency for protons). Distinct structures, frequently described in the specialized literature, are discussed here. Usually the RF coils proposed are resonant circuits with distributed inductance and capacitance. We have built different types of resonators and its performance were compared. With the resonators developed here we have been able to obtain proton density images of good quality. (author)

  8. High Temperature Polymers for use in Fuel Cells

    Science.gov (United States)

    Peplowski, Katherine M.

    2004-01-01

    NASA Glenn Research Center (GRC) is currently working on polymers for fuel cell and lithium battery applications. The desire for more efficient, higher power density, and a lower environmental impact power sources has led to interest in proton exchanges membrane fuels cells (PEMFC) and lithium batteries. A PEMFC has many advantages as a power source. The fuel cell uses oxygen and hydrogen as reactants. The resulting products are electricity, heat, and water. The PEMFC consists of electrodes with a catalyst, and an electrolyte. The electrolyte is an ion-conducting polymer that transports protons from the anode to the cathode. Typically, a PEMFC is operated at a temperature of about 80 C. There is intense interest in developing a fuel cell membrane that can operate at higher temperatures in the range of 80 C- 120 C. Operating the he1 cell at higher temperatures increases the kinetics of the fuel cell reaction as well as decreasing the susceptibility of the catalyst to be poisoned by impurities. Currently, Nafion made by Dupont is the most widely used polymer membrane in PEMFC. Nafion does not function well above 80 C due to a significant decrease in the conductivity of the membrane from a loss of hydration. In addition to the loss of conductivity at high temperatures, the long term stability and relatively high cost of Nafion have stimulated many researches to find a substitute for Nafion. Lithium ion batteries are popular for use in portable electronic devices, such as laptop computers and mobile phones. The high power density of lithium batteries makes them ideal for the high power demand of today s advanced electronics. NASA is developing a solid polymer electrolyte that can be used for lithium batteries. Solid polymer electrolytes have many advantages over the current gel or liquid based systems that are used currently. Among these advantages are the potential for increased power density and design flexibility. Automobiles, computers, and cell phones require

  9. PEM-fuel cells for mobile application. Sub task: development of electrocatalysts. Final report; PEM-Brennstoffzelle fuer mobile Anwendung. Teilprojekt: Katalysatorenentwicklung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Starz, K A

    1999-01-01

    PEM fuel cells are gaining increasing importance for use in automotive application. The goal of the research program reported here was to develop the basic technology and components for PEMFC stacks for use in transport applications. The sub-task of Degussa was to develop improved electrocatalysts for PEMFC single cells and stacks. The technical objectives of the research project were met. Electrocatalysts, characterized by a high Pt-dispersion, high surface area and excellent activity, were developed. With this material, considerable progress was made to reduce the total platinum loading of PEMFC cells and stacks to about 0,5 mgPt/cm{sup 2}. With this value, the goal of the program (<0,8 mg/cm{sup 2}) was significantly surpassed. Additionally, higher power densities of >0.4 W/cm{sup 2} were achieved at Degussa for hydrogen/air and reformate/air operation of the PEMFC. A CO-tolerant anode electrocatalyst, exhibiting a CO-tolerance of up to 100 ppm CO, enables the operation of PEMFC stacks with on-board generated methanol reformate. The performance of the new electrocatalyst materials was verified by DaimlerChrysler in a PEMFC demonstration stack at the end of the program. (orig.) [Deutsch] PEM-Brennstoffzellen gewinnen fuer die mobile Anwendung immer mehr an Bedeutung. Im Rahmen des hier beschriebenen Leitprojektes sollten die Basistechnologien fuer den Einsatz der PEM-Brennstoffzelle im mobilen Bereich (Elektrotraktion) entwickelt werden. Das Teilprojekt der Degussa befasst sich mit der Entwicklung von verbesserten Elektrokatalysatoren fuer PEM-Brennstoffzellenstacks. Die technischen Arbeitsziele des Vorhabens wurden erreicht. So konnten Elektrokatalysatoren bereitgestellt werden, die sich durch eine hohe Pt-Dispersion, eine grosse Pt-Oberflaeche sowie eine sehr gute Aktivitaet auszeichnen. Mit diesen Elektrokatalysatoren gelang es, die Platinbeladung der PEM-Elektroden (Anode und Kathode) erheblich abzusenken. Mit einer Gesamtplatinbeladung von 0,5 mg/cm{sup 2

  10. Actitud Positiva: la base para la competitividad

    Directory of Open Access Journals (Sweden)

    Marco Anderson Espinoza

    2008-04-01

    Full Text Available Una estrategia empresarial enfocado en el mejoramiento continuo de la productividad para la competitividad, depende significativamente del manejo inteligente de tres variables visibles:Calidad, Entrega oportuna y Costo. No obstante, estas tres variables no suelen sersuficientes. La estrategia debe ser complementada con el manejo adecuado de variables intangibles como la Motivación y las Condiciones de Trabajo, con la aplicación de Tecnología Ambientalmente Amigable, en un marco de Actitud Positiva.A final de cuentas, la Actitud Positiva es fundamental para el recurso humano de cualquier organización, a fin de construir una plataforma sólida y estable que sirva de base para soportar un proceso sostenible de mejoramiento de la productividad, para aumentar la competitividad como estrategia empresarial exitosa.

  11. Technological properties of kaolin from Para; Propriedades tecnologicas do caulin do Para

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrando, E.; Martin-Cortes, G.R.; Esper, F.J.; Wiebeck, H.; Alves Junior, P.; Valenzuela-Diaz, F.R., E-mail: germac@usp.br [Universidade de Sao Paulo (PMT/EP/USP), Sao Paulo, SP (Brazil). Escola Politecnica. Departamento de Engenharia Metalurgica e de Materiais

    2011-07-01

    The NE of the State of Para, is notable for its large reserves of kaolin for paper. Kaolin is a mineral composed of hydrated aluminum silicates such as kaolinite and halloysite. The exploitation of these reserves to generate products with higher commercial value, especially in the industries of adsorbents and catalysts, is what motivates the continuous study of technological properties of the Amazon kaolin's. Thus, this paper presents a technological characterization of a sample of kaolin from Para State by X-ray diffraction, SEM - scanning electron microscopy and infrared spectroscopy. The results of preliminary tests indicate that the sample consists for the most part by kaolinite present in low concentrations of quartz and anatase. (author)

  12. Comparative analysis between a PEM fuel cell and an internal combustion engine driving an electricity generator: Technical, economical and ecological aspects

    International Nuclear Information System (INIS)

    Braga, Lúcia Bollini; Silveira, Jose Luz; Evaristo da Silva, Marcio; Machin, Einara Blanco; Pedroso, Daniel Travieso; Tuna, Celso Eduardo

    2014-01-01

    In the recent years the fuel cells have received much attention. Among various technologies, the Proton Exchange Membrane Fuel Cell (PEMFC) is currently the most appropriate and is used in several vehicles prototype. A comparative technical, economical and ecological analysis between an Internal Combustion Engine fueled with Diesel driving an electricity Generator (ICE-G) and a PEMFC fed by hydrogen produced by ethanol steam reforming was performed. The technical analysis showed the advantages of the PEMFC in comparison to the ICE-G based in energetic and exergetic aspects. The economic analysis shows that fuel cells are not economic competitive when compared to internal combustion engine driving an electricity generator with the same generation capacity; it will only be economically feasible in a long term; due to the large investments required. The environmental analysis was based on concepts of CO 2 equivalent, pollution indicator and ecological efficiency. Different to the ICE-G system, the Fuel Cell does not emit pollutants directly and the emission related to this technology is linked mainly with hydrogen production. The ecological efficiency of PEMFC was 96% considering the carbon dioxide cycle, for ICE-G system this parameter reach 51%. -- Highlights: • The exergetic efficiency of ICE-G was 22% and for the fuel cell was 40%. • The PEM fuel cell at long-term become economically competitive compared to ICE-G. • The ecological efficiency of PEM fuel cell was 96% and Diesel ICE-G was 51%

  13. A novel cogeneration system: A proton exchange membrane fuel cell coupled to a heat transformer

    International Nuclear Information System (INIS)

    Huicochea, A.; Romero, R.J.; Rivera, W.; Gutierrez-Urueta, G.; Siqueiros, J.; Pilatowsky, I.

    2013-01-01

    This study focuses on the potential of a novel cogeneration system which consists of a 5 kW proton exchange membrane fuel cell (PEMFC) and an absorption heat transformer (AHT). The dissipation heat resulting from the operation of the PEMFC would be used to feed the absorption heat transformer, which is integrated to a water purification system. Therefore, the products of the proposed cogeneration system are heat, electricity and distilled water. The study includes a simulation for the PEMFC as well as experimental results obtained with an experimental AHT facility. Based on the simulation results, experimental tests were performed in order to estimate the performance parameters of the overall system. This is possible due to the matching in power and temperatures between the outlet conditions of the simulated fuel cell and the inlet requirements of the AHT. Experimental coefficients of performance are reported for the AHT as well as the overall cogeneration efficiency for the integrated system. The results show that experimental values of coefficient of performance of the AHT and the overall cogeneration efficiency, can reach up to 0.256 and 0.571, respectively. This represents an increment in 12.4% of efficiency, compared to the fuel cell efficiency working individually. This study shows that the combined use of AHT systems with a PEMFC is possible and it is a very feasible project to be developed in the Centro de Investigación en Energía (Centre of Energy Research), México.

  14. Desarrollo de manuales para la inspección y revisión de instalaciones petrolíferas para uso propio, para suministro a vehículos y transporte de mercancías peligrosas por carretera

    OpenAIRE

    Cardell Bilbao, Pablo Juan

    2010-01-01

    El objetivo de este proyecto es la realización de un manual que aúne y clarifique toda la documentación, la normativa y los procedimientos necesarios para cumplir las auditorías (revisiones e inspecciones) en las instalaciones existentes, los trámites para la apertura de nuevas instalaciones para suministro a vehículos (especialmente las Estaciones de Servicio (EESS), y para Usos Propios (UUPP) en Canarias, y el transporte de mercancías peligrosas por carretera (ADR), mostrando el procedimien...

  15. Oxitocina: nuevas perspectivas para una droga antigua

    OpenAIRE

    Steven L. CLARK; Kathleen Rice SIMPSON; G. Eric KNOX; Thomas J. GARITE

    2010-01-01

    La oxitocina es el medicamento más comúnmente asociada con la prevención de complicaciones perinatales y recientemente fue incluida por el Instituto para la Administración Medicamentosa Segura (Institute for Safe Medication Practices - ISMP) en una pequeña lista de medicamentos “con alto grado de riesgos”, lo que puede “necesitar salvaguardas especiales para reducir el riesgo de error”. Las recomendaciones actuales para administrar este medicamento son vagas en relación a la indicación, tiemp...

  16. INICIATIVAS PARA EL CAMBIO

    Directory of Open Access Journals (Sweden)

    César Alfonso Defrancisco-Larrañaga

    2013-07-01

    Full Text Available El planeta no atraviesa por su mejor momento en materia de conservación y renovación de sus recursos naturales. Claramente en los últimos tiempos los recursos hídricos han venido haciéndose cada vez menores; el hombre ha notado con preocupación y vivido en carne propia este fenómeno, que de no ser tratado a tiempo, podría atentar contra la existencia misma. Esto lo ha alentado a buscar métodos que sirvan como solución para contrarrestar éste mal y crear conciencia entre sus iguales, para así poder garantizar su permanencia y la de su entorno durante muchas generaciones. En países desarrollados del continente europeo y en algunos lugares de América del norte, el uso de sistemas de reutilización y tratamiento de aguas grises y aprovechamiento de las aguas lluvias se ha convertido en una constante y nos están dando las pautas para poder seguir el ejemplo y así de esta manera poder aportar a la causa ambiental y a su vez crear un ahorro en nuestros gastos mensuales de consumo.

  17. AUTONOMÍA PARA APRENDER Y AUTONOMÍA PARA VIVIR

    Directory of Open Access Journals (Sweden)

    Miryam Narváez Rivero

    2005-04-01

    Full Text Available RESUMEN: El sistema educativo tiene el reto actual de formar individuos autónomos. Esta autonomía no implica solo el que las personas tengan los recursos necesarios para aprender a aprender, sino que puedan convivir armónicamente en comunidad, escuchándose a sí mismos para tomar sus propias decisiones, sin estar determinados por deseos instintivos ni modelos coercitivos impuestos por la sociedad. Así, para desarrollar autonomía, le corresponde a la educación trabajar tres elementos: la voluntad, la libertad y la autoestima. De esta forma, una educación promotora de una verdadera autonomía deberá tener un carácter dialógico, haciendo hincapié en la integración solidaria de la persona con su comunidad. Nos referimos a una persona que no ha renunciado a sus metas ni aspiraciones, sino que sabe cómo guiarlas hacia un proyecto común de bienestar general. ABSTRACT: The educative system’s latest challenge is to educate independent individuals. This autonomy does not just imply that people have the necessary resources to learn to learn, but the ones they need to live together in harmony with others, listening to themselves to make their own decisions without being determined by instinctive desires nor coercive models imposed by the society. It is so, that to develop autonomy, the educational system must work with these three elements: will, freedom and self-esteem. Also, an educational system which promotes a true autonomy must have a dialogic character, insisting on the individual solidarity integration with the community; with this, we mean a person who has not resigned to his goals or aspirations, but that knows how to guide them towards a common project for the community well-being.

  18. Significado de la calidad de vida del adulto mayor para sí mismo y para su familia

    Directory of Open Access Journals (Sweden)

    Martha Vera

    2007-09-01

    Full Text Available Objetivo: Comprender el significado que la expresión lingüística ‘calidad de vida del adulto mayor’ tiene para el adulto mayor y para su familia. Diseño: Estudio cualitativo, descriptivo, interpretativo - comprensivo, fundamentado en la Teoría de las Representaciones Sociales. Lugar: Asentamiento Humano Laura Caller, en Los Olivos. Participantes: Adultos mayores y sus respectivos grupos familiares. Métodos: Las técnicas e instrumentos utilizados fueron la observación, entrevista a profundidad y grupos focales; guía de observación y dos cuestionarios con ocho preguntas norteadoras, previamente validados. Principales medidas de resultados: Significado de calidad de vida para el adulto mayor y para la familia. Resultados: Participaron dieciséis adultos mayores con sus respectivos grupos familiares, entre 2004 y 2006. Los discursos a través de la ‘objetivación’ y el ‘anclaje’ y los análisis general, ideográfico-axial y nomotético-selectivo permitieron la emergencia de cuatro representaciones sociales: a conocimiento sobre la vejez y ser un adulto mayor; b elementos principales y secundarios del significado de calidad de vida del adulto mayor; c valores y actitudes del adulto mayor y familia sobre la calidad de vida; y, d necesidades del adulto mayor como ser social y la calidad de vida. Conclusiones: Para el adulto mayor, calidad de vida significa tener paz y tranquilidad, ser cuidado y protegido por la familia con dignidad, amor y respeto, y tener satisfechas como ser social sus necesidades de libre expresión, decisión, comunicación e información. Para la familia, que el adulto mayor satisfaga sus necesidades de alimentación, vestido, higiene y vivienda.

  19. NEW POLYMER ELECTROLYTE MEMBRANES FOR FUEL CELLS OPERATING ABOVE 100°C

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf; He, Ronghuan

    2003-01-01

    The state-of-the-art of PEMFC technology is based on perfluorosulfonic acid (PFSA) polymer membranes operating at a typical temperature of 80°C. The newest development in the field is alternative polymer electrolytes for operation above 100°C. This paper is devoted to a review on the development......, which is classified into three groups: modified PFSA membranes, alternative sulfonated polymer and their inorganic composite membranes and acid-base complex membranes. High temperature PEMFC has been demonstrated with advanced features such as fast electrode kinetics, high CO tolerance, simple thermal...

  20. Durability of Carbon Nanofiber (CNF) & Carbon Nanotube (CNT) as Catalyst Support for Proton Exchange Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Borghei, Maryam; Lund, Peter

    2013-01-01

    a standard polyol method were prepared and fabricated as cathodes of Membrane Electrode Assemblies (MEA) for PEMFC. Both the catalysts as such and the MEAs made out of them were evaluated regarding to thermal and electrochemical stability using traditional carbon black (Vulcan XC72) as a reference. Thermal...... gravimetric analysis (TGA), cyclic voltammetry (CV), polarization curve and impedance spectroscopy were applied on the samples under accelerated stress conditions. The carbon nano-materials demonstrated better stability as support for nano-sized platinum catalyst under PEMFC related operating conditions. Due...