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Water management in a passive direct methanol fuel cell

Passive direct methanol fuel cells (DMFCs) are under development for use in portable applications because of their enhanced energy density in comparison with other fuel cell types. The most significant obstacles for DMFC development are methanol and water crossover because methanol diffuses through the membrane generating heat but no power. The presence of a large amount of water floods the cathode and reduces ...

Modeling and simulation of micro direct methanol Fuel Cells

Fuel cells have unique technological attributes: efficiency, absence of moving parts and low emissions. The Direct Methanol Fuel Cell (DMFC) has attracted much attention due to its potential applications as a power source for transportation and portable electronic devices. With the advance of micromachining technologies, miniaturization of power sources became one of the trends of evolution of research in this ...

One-dimensional and non-isothermal model for a passive DMFC

Passive direct methanol fuel cells (DMFCs) are promising energy sources for portable electronic devices. Different from DMFCs with active fuel feeding systems, passive DMFCs with nearly stagnant fuel and air tend to bear comparatively less power densities. A steady state, one-dimensional, multi-component and thermal model is described and applied to simulate the operation of a passive direct methanol fuel cell....

Heat and mass transfer effects in a passive direct methanol fuel cell: 1D model

A direct methanol fuel cell with low methanol crossover and high methanol conce...

The direct methanol fuel cell (DMFC) with proton exchange membrane (PEM) as electrolyte and liquid methanol/water as the energy carrier is a promising power source for micro and various portable electronic devices (mobile phones, PDA’s, laptops and multimedia equipment). However a number of issues need to be resolved before DMFC can be commercially viable such as the methanol crossover and water crossover which...

Estratégias de comunicação para a divulgação científica de resultados de pesqui...

Esta publicação traz informações sobre o projeto ComCiência Florestal, que trata sobre a divulgação científica da pesquisa florestal realizada na Embrapa Rondônia. ; 2008

Water management in direct methanol fuel cells

Direct methanol fuel cell (DMFC) are a promising power source for micro and portable applications due to their high energy density and inherent simplicity of operation with methanol as the liquid fuel. Present state-of-the-art optimised operating conditions are elevated cell temperatures to improve the anode reaction, high air stoichiometries to prevent cathode flooding and dilute methanol solutions to mitigate...

Heat and mass transfer effects in direct methanol fuel cell: 1D model

Models play an important role in fuel cell development since they facilitate a better understanding of parameters affecting the performance of fuel cells and fuel cells systems. In this work, a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the DMFC is presented. The model accounts for the kinetics of the multi-step methan...

Water transport through a PEM Fuel Cell: a one-dimensional model with heat tran...

One of the critical problems and design issues of PEM fuel cells is the water management because the membrane’s hydration determines the performance and durability of the cell. In this work, a steady state, one-dimensional model accounting for coupled heat and mass transfer in a single PEM fuel cell is presented. Two-phase flow effects are neglected. The anode and cathode flow channels are treated using the con...

Desenvolvimento de cenários futuros possíveis para o manejo florestal sustentáv...

O presente trabalho refere-se aos resultados obtidos com a utilização da metodologia Cenários Futuros Possíveis, referendada pelo Programa ASB Partnership for the Tropical Forest Margins do Centro Mundial de Sistemas Agroflorestais ICRAF, sediado no Quênia, África. O referido programa realizou na cidade de Chiang Mai, Tailândia, de 17 a 28 de novembro de 2004, um treinamento sobre esta metodologia, do qual part...