Quantitative Analysis of Energy and Power on Direct Methanol Fuel Cell Systems PDF Download

Author: Rongzhong Jiang
Publisher:
ISBN:
Category : Fuel cells
Languages : en
Pages : 24

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Author: Electrochemical Society. Energy Technology Division
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 366

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"Energy Technology, Physical Electrochemistry and Battery Divisions."

Author: Albert R. Landgrebe
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 252

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Author: L. O. Vasquez
Publisher: Nova Publishers
ISBN: 9781600216695
Category : Science
Languages : en
Pages : 502

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Book Description
Fuel cells differ from batteries in that they consume reactants, which must be replenished, while batteries store electrical energy chemically in a closed system. Additionally, while the electrodes within a battery react and change as a battery is charged or discharged, a fuel cell's electrodes are catalytic and relatively stable.

Author: Srikanth Arisetty
Publisher:
ISBN: 9781124240503
Category : Fuel cells
Languages : en
Pages :

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Book Description
Direct Methanol Fuel Cells (DMFCs) have been demonstrated extensively as electrical power sources for portable applications. In DMFCs, the chemical energy stored in methanol is converted directly to electrical energy through a number of chemical, transport and kinetic processes. The overall efficiency of the DMFC system can be improved by optimizing these processes with precise control over operating conditions. The goal of this research is to evaluate optimal operating conditions and system design for improving the DMFC's electrical performance through a combination of experimental strategies and process models. A DMFC system incorporating metal foams as the flow field was designed to increase system efficiency. The influence of metal foam parameters and operating conditions on fuel cell performance was investigated. Our results indicated that due to the opposing effects of methanol concentration on anode and cathode kinetics, there exists an optimal value of methanol concentration at each current density that will yield the highest electrical performance. A control algorithm employing feedback from the fuel cell voltage was implemented to dynamically adjust the methanol feed concentration for peak DMFC performance. Additionally, water and methanol crossover fluxes across the membrane were also measured to understand their transport rates under different conditions. The physico-chemical processes in DMFCs were investigated by developing an accurate mathematical model coupling mass transport with reaction kinetics within the five-layer membrane electrode assembly of the DMFC. An experimental scheme was developed to measure the overpotential contributions of anode methanol oxidation, cathode oxygen reduction and cathode methanol oxidation. Subsequently, the kinetic constants for these three reactions are characterized for various catalyst loadings. The model predicted that methanol undergoes electrochemical adsorption on the Pt/C cathode catalyst layer, followed by both electrochemical and chemical oxidation. The overpotential loss due to methanol oxidation on the cathode with 2 mg/cm 2 catalyst loading is as large as 80 mV at 20 mA/cm 2 . Our model indicated that most of the methanol adsorbed on the cathode catalyst undergoes purely chemical oxidation with oxygen and causes mass transport limitations for oxygen electro-reduction. We also found that the transport of methanol to the anode catalyst layer was significantly enhanced by the convection of CO 2 bubbles towards the flow field. This model should prove useful in optimizing the supply rates of methanol and oxygen in DMFCs.

Author: Kingshuk Dutta
Publisher: Elsevier
ISBN: 0128191597
Category : Technology & Engineering
Languages : en
Pages : 565

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Book Description
Direct Methanol Fuel Cell Technology presents the overall progress witnessed in the field of DMFC over the past decade, highlighting the components, materials, functions, properties and features, designs and configurations, operations, modelling, applications, pros and cons, social, political and market penetration, economics and future directions. The book discusses every single aspect of DMFC device technology, the associated advantages and drawbacks of state-of-the-art materials and design, market opportunities and commercialization aspects, and possible future directions of research and development. This book, containing critical analyses and opinions from experts around the world, will garner considerable interest among actual users/scientists/experts. - Analyzes developments of membrane electrolytes, electrodes, catalysts, catalyst supports, bipolar plates, gas diffusion layers and flow channels as critical components of direct methanol fuel cells - Includes modeling of direct methanol fuel cells to understand their scaling up potentials - Discusses commercial aspects of direct methanol fuel cells in terms of market penetration, end application, cost, viability, reliability, social and commercial perception, drawbacks and prospects

Author: Paul Montagna
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The rapid increase in instability of fossil fuels has led to a more aggressive search for reliable alternative energy. This has led to the rise of fuel cells as a popular and effective source of energy in large-scale applications. However, their development for usage in small-scale applications is still in its early stages. Many factors and concerns including, but not limited to, flow chamber geometry, electrode geometry, fuel molarity, fuel flow rate, gas flow rates, and electrode fabrication methods, must be further explored and analyzed. Once this is done, a feasible micro fuel cell capable of replacing current comparable lithium-ion batteries in powering small electronics may be developed. This thesis presents a review of micro direct methanol fuel cells (DMFC's) and discusses how each of the above parameters, as well as others, factor into DMFC performance. Initial iterations of a mathematical model used to predict the performance of a DMFC as a function of various experimental parameters is also discussed. Several of these factors, including fuel molarity and flow rate, were further explored using the presented experimental setup and procedure. From this, it was concluded that a methanol fuel molarity of 1M and a fuel flow rate of 18 ml/hr resulted in the highest power densities. It should be noted that these parameters were independently tested, using constant standard parameters to isolate a single testing parameter. While both the experimental and model results are promising, they are just the beginning of the modeling and experimental testing required to produce a feasible final product. Future research plans include further refining the mathematical model and performing experimental tests to measure power density as a function of electrode geometry and fuel temperature.

Author: Dave Edlund
Publisher: CRC Press
ISBN: 9814303143
Category : Science
Languages : en
Pages : 199

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Book Description
This book details state-of-the-art fuel cell systems incorporating methanol reformers as the source of purified hydrogen (rather than compressed hydrogen). Beginning with an overview of PEM fuel cells, the book discusses the various technical approaches to methanol reforming and hydrogen purification. A unique theme carried throughout the discussio

Author: Goktug Aydinli
Publisher:
ISBN: 9781109802412
Category : Dissertations, Academic
Languages : en
Pages : 53

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Book Description
This thesis presents a detailed reliability assessment of low power portable DMFC systems. At first, system configuration and model are developed to calculate the reliability of the DMFC system. A sensitivity analysis on the reliability of DMFC is also used to determine the components that are critical to ensure the reliability of the system. For reliability assessment and sensitivity analysis, a reliability block diagram (RBD) is used to develop the analytical model of the DMFC system. A state space model is used to formulate the state-space Markov model (MM), which is a very effective technique for calculating repairable system reliability and availability. Since most of the systems and associated components spend their lifetime in the steady state period, this research is focused mainly on the steady state operational period. The failure time and repair time for repairable DMFC systems are fitted with a homogeneous Poisson process (HPP) and exponential distribution. The parameters of these models can be considered as constant for the steady state period. These constant parameters are used in the MM transition matrix to calculate the availability and reliability of low power portable DMFC systems. Simulation results calculated based on the state space model for 5000 hours indicate that the system reliability is 90.51% and steady state system availability is 99.94%.

Author: Ibrahim Dincer
Publisher: Academic Press
ISBN: 0123838614
Category : Technology & Engineering
Languages : en
Pages : 657

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Book Description
Advanced Power Generation Systems examines the full range of advanced multiple output thermodynamic cycles that can enable more sustainable and efficient power production from traditional methods, as well as driving the significant gains available from renewable sources. These advanced cycles can harness the by-products of one power generation effort, such as electricity production, to simultaneously create additional energy outputs, such as heat or refrigeration. Gas turbine-based, and industrial waste heat recovery-based combined, cogeneration, and trigeneration cycles are considered in depth, along with Syngas combustion engines, hybrid SOFC/gas turbine engines, and other thermodynamically efficient and environmentally conscious generation technologies. The uses of solar power, biomass, hydrogen, and fuel cells in advanced power generation are considered, within both hybrid and dedicated systems. The detailed energy and exergy analysis of each type of system provided by globally recognized author Dr. Ibrahim Dincer will inform effective and efficient design choices, while emphasizing the pivotal role of new methodologies and models for performance assessment of existing systems. This unique resource gathers information from thermodynamics, fluid mechanics, heat transfer, and energy system design to provide a single-source guide to solving practical power engineering problems. - The only complete source of info on the whole array of multiple output thermodynamic cycles, covering all the design options for environmentally-conscious combined production of electric power, heat, and refrigeration - Offers crucial instruction on realizing more efficiency in traditional power generation systems, and on implementing renewable technologies, including solar, hydrogen, fuel cells, and biomass - Each cycle description clarified through schematic diagrams, and linked to sustainable development scenarios through detailed energy, exergy, and efficiency analyses - Case studies and examples demonstrate how novel systems and performance assessment methods function in practice