نتایج جستجو برای: pem fuel cells
تعداد نتایج: 1443225 فیلتر نتایج به سال:
Objectives • Develop realistic and internally consistent detailed designs for automotive gasoline fuel processor/ proton exchange membrane (PEM) fuel cell systems and direct hydrogen PEM fuel cell systems by using current-year technology. • Apply Design for Manufacture and Assembly (DFMA) design and costing techniques to compare system designs at low, medium, and high annual production rates. •...
proton exchange membrane fuel cells (pemfcs) with a dead-ended anode and cathode can obtain high hydrogen and oxygen utilization by a comparatively simple system. nevertheless, the accumulation of the water in the anode and cathode channels might cause a local fuel starvation degrading the performance and durability of pemfcs. in this study, a brand new design for a polymer electrolyte membrane...
The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free O...
Parasitic capacitances of Proton Exchange Membrane (PEM) fuel cell are causing electrical effects resulting with change of dynamic behavior of fuel cell stack output voltage. This paper shows PEM fuel cell dynamic model with capability of easy integration of humidity, temperature and pressures dynamics, as well as their control. Fuel cell stack dynamic model was linked with boost converter aver...
Polymer Electrolyte Membrane (PEM) fuel cells incorporating microchannels (D<500 μm) can benefit from improved fuel delivery and convective cooling. However, this requires a better understanding of twophase microchannel transport phenomena, particularly liquid-gas interactions and liquid clogging in cathode air-delivery channels. This paper develops optical fluorescence imaging of water films i...
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 widespre...
PEM (Proton Exchange Membrane) fuel cells show characteristics of high power density, low operating temperature and fast start-up capability, which make them potentially suitable to replace conventional power sources (e.g. internal combustion engines) as Auxiliary Power Units (APU) for on-board applications. This paper presents a methodology for a preliminary investigation on either sizing and ...
The performance of polymer electrolyte membrane (PEM) fuel cell is mainly influenced by ohmic, activation, and concentration overpotentials. Ohmic overpotential is directly proportional to electric resistance in the fuel cell components that can be estimated from the experimental data or from the empirical relation for the cell polarization curve. However, such simple relation is not available ...
Proton Exchange Membrane (PEM) fuel cells are gaining popularity as a replacement to the internal combustion engine in automobiles. This application will demand high levels of performance from the fuel cell making it critical that proper water management is maintained. One of the areas of interest in water management is the transport of water through the Gas Diffusion Medium (GDM) on the cathod...
This paper describes and demonstrates a new method for determination of current density distribution in an operating polymer electrolyte membrane ~PEM! fuel cell. The technique is a modification of the current mapping technique that relies on an array of shunt resistors embedded within a current collecting plate. Standard, nonaltered membrane electrode assemblies are utilized with gas diffusion...
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