scholarly journals Cooling Design for PEM Fuel-Cell Stacks Employing Air and Metal Foam: Simulation and Experiment

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2687
Author(s):  
Ali A. Hmad ◽  
Nihad Dukhan
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Metal Foam ◽  
Air Flow ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Total Output ◽  
Pumping Power ◽  
Maximum Heat ◽  
Simulation And Experiment

A new study investigating the cooling efficacy of air flow inside open-cell metal foam embedded in aluminum models of fuel-cell stacks is described. A model based on a commercial stack was simulated and tested experimentally. This stack has three proton exchange membrane (PEM) fuel cells, each having an active area of 100 cm2, with a total output power of 500 W. The state-of-the-art cooling of this stack employs water in serpentine flow channels. The new design of the current investigation replaces these channels with metal foam and replaces the actual fuel cells with aluminum plates. The constant heat flux on these plates is equivalent to the maximum heat dissipation of the stack. Forced air is employed as the coolant. The aluminum foam used had an open-pore size of 0.65 mm and an after-compression porosity of 60%. Local temperatures in the stack and pumping power were calculated for various air-flow velocities in the range of 0.2–1.5 m/s by numerical simulation and were determined by experiments. This range of air speed corresponds to the Reynolds number based on the hydraulic diameter in the range of 87.6–700.4. Internal and external cells of the stack were investigated. In the simulations, and the thermal energy equations were solved invoking the local thermal non-equilibrium model—a more realistic treatment for airflow in a metal foam. Good agreement between the simulation and experiment was obtained for the local temperatures. As for the pumping power predicted by simulation and obtained experimentally, there was an average difference of about 18.3%. This difference has been attributed to the poor correlation used by the CFD package (ANSYS) for pressure drop in a metal foam. This study points to the viability of employing metal foam for cooling of fuel-cell systems.

Fabrication and Performance Evaluation of Miniaturized Proton Exchange Membrane (PEM) Fuel Cells

2003 ◽  
Author(s):  
Tao Zhang ◽  
Pei-Wen Li ◽  
Qing-Ming Wang ◽  
Laura Schaefer ◽  
Minking K. Chyu
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Free Convection ◽  
Current Density ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Cathode Side ◽  
Ohmic Loss ◽  
Fuel Cell Performance

Two types of miniaturized PEM fuel cells are designed and characterized in comparison with a compact commercial fuel cell device in this paper. One has Nafion® membrane electrolyte sandwiched by two brass bipolar plates with micromachined meander-like gas channels. The cross-sectional area of the gas flow channel is approximately 250 by 250 (μm). The other uses the same Nafion® membrane and anode structure, but in stead of the brass plate, a thin stainless steel plate with perforated round holes is used at cathode side. The new cathode structure is expected to allow oxygen (air) being supplied by free-convection mass transfer. The characteristic curves of the fuel cell devices are measured. The activation loss and ohmic loss of the fuel cells have been estimated using empirical equations. Critical issues such as flow arrangement, water removing and air feeding modes concerning the fuel cell performance are investigated in this research. The experimental results demonstrate that the miniaturized fuel cell with free air convection mode is a simple and reliable way for fuel cell operation that could be employed in potential applications although the maximum achievable current density is less favorable due to limited mass transfer of oxygen (air). The relation between the fuel cell dimensions and the maximum achievable current density is also discussed with respect to free-convection mode of air feeding.

Nonlinear Analysis of Two-Phase Instabilities in PEMFC Parallel-Channel Cathodes

2010 ◽  
Author(s):  
Nicholas Siefert ◽  
Chi-Hsin Ho ◽  
Shawn Litster
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Liquid Water ◽  
Proton Exchange Membrane ◽  
Critical Issue ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Stoichiometric Ratio ◽  
Two Phase ◽  
Voltage Loss

Liquid water management is a critical issue in the development of proton exchange membrane (PEM) fuel cells. Liquid water produced electrochemically can accumulate and flood the microchannels in the cathodes of PEM fuel cells. Since the liquid coverage of the cathode can fluctuate in time for two-phase flow, the rate of oxygen transport to the cathode catalyst layer can also fluctuate in time, and this can cause the fuel cell power output to fluctuate. This paper will report experimental data on the voltage loss and the voltage fluctuations of a PEM fuel cell due to flooding as a function of the number of parallel microchannels and the air flow rate stoichiometric ratio. The data was analyzed to identify general scaling relationships between voltage loss and fluctuations and the number of channels in parallel and the air stoichiometric ratio. The voltage loss was found to scale proportionally to the square root of the number of channels divided by the air stoichiometric ratio. The amplitude of the fluctuations was found to be linearly proportional to the number of microchannels and inversely proportional to the air stoichiometric ratio squared. The data was further analyzed by plotting power spectrums and by evaluating the non-linear statistics of the voltage time-series.

Component Failure Analysis From the U.S. Army ERDC-CERL Residential Proton Exchange Membrane Fuel Cells Demonstration

2006 ◽  
Author(s):  
Scott A. Kenner ◽  
Nicholas M. Josefik ◽  
Scott M. Lux ◽  
James L. Knight ◽  
Melissa K. White ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Fuel Cell Stack ◽  
The Mean ◽  
Exchange Membrane ◽  
Mean Time ◽  
The U.S

Background: The U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (ERDC-CERL) continues to manage The Department of Defense (DoD) Residential Proton Exchange Membrane (PEM) Fuel Cell Demonstration Project. This project was funded by the United States Congress for fiscal years 2001 through 2004. A fleet of 91 residential-scale PEM fuel cells, ranging in size from 1 to 5 kW, has been demonstrated at various U.S. DoD facilities around the world. Approach: The performance of the fuel cells has been monitored over a 12-month field demonstration period. A detailed analysis has been performed cataloging the component failures, investigating the mean time of the failures, and the mean time between failures. A discussion of the lifespan and failure modes of selected fuel cell components, based on component type, age, and usage will be provided. This analysis also addresses fuel cell stack life for both primary and back-up power systems. Several fuels were used throughout the demonstration, including natural gas, propane, and hydrogen. A distinction will be made on any variances in performance based on the input fuel stock. Summary: This analysis will provide an overview of the ERDC-CERL PEM demonstration fuel cell applications and the corresponding data from the field demonstrations. Special emphasis will be placed on the components, fuel cell stack life, and input fuel characteristics of the systems demonstrated.

Alloys that form conductive and passivating oxides for proton exchange membrane fuel cell bipolar plates

2004 ◽  
Vol 19 (6) ◽  
pp. 1723-1729 ◽  
Author(s):  
Neil Aukland ◽  
Abdellah Boudina ◽  
David S. Eddy ◽  
Joseph V. Mantese ◽  
Margarita P. Thompson ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Oxide Films ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Bipolar Plates ◽  
Concentrated Solutions ◽  
Exchange Membrane

During the operation of proton exchange membrane (PEM) fuel cells, a high-resistance oxide is often formed on the cathode surface of base metal bipolar plates. Over time, this corrosion mechanism leads to a drop in fuel cell efficiency and potentially to complete failure. To address this problem, we have developed alloys capable of forming oxides that are both conductive and chemically stable under PEM fuel cell operating conditions. Five alloys of titanium with tantalum or niobium were investigated. The oxides were formed on the alloys by cyclic voltammetry in solutions mimicking the cathode- and anode-side environment of a PEM fuel cell. The oxides of all tested alloys had lower surface resistance than the oxide of pure titanium. We also investigated the chemical durability of Ti–Nb and Ti–Ta alloys in more concentrated solutions beyond those typically found in PEM fuel cells. The oxide films formed on Ti–Nb and Ti–Ta alloys remained conductive and chemically stable in these concentrated solutions. The stability of the oxide films was evaluated; Ti alloys having 3% Ta and Nb were identified as potential candidates for bipolar plate materials.

Experimental Analysis of PEM Fuel Cells With Biomimetical Mixed Flows as Gas Distributors

2010 ◽  
Author(s):  
C. E. Damian-Ascencio ◽  
A. Herna´ndez-Guerrero ◽  
A. Alatorre-Ordaz ◽  
A. Cuauhtemoc-Rubio ◽  
F. Elizalde-Blancas
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Current Collector ◽  
Natural World ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Cathode Side ◽  
Anode Side ◽  
Collector Plate ◽  
Mixed Flows

A proton exchange membrane fuel cell (PEMFC) is an electrochemical device that converts the chemical energy from the gases into electrical energy. The PEMFCs consist of many parts, and the current collector plate is one of the key components among them. Channels in the bipolar plate distribute air on the cathode side and hydrogen on the anode side. Theoretically a fuel cell produces more current as more fuel is supplied. However the way in which the gases are supplied affects dramatically the performance of the cell. The present paper shows how the mixed flows improve the current density produced by fuel cells. Polarization and power density curves are presented. The results suggest that a flow with two levels of bifurcations is preferred for the anode side. This behavior is expected due to the similitude with the performance of the natural world in which geometries with this type of bifurcations transport the nutrients inside the tree leaves and plants.

Fuel Cell Applications of Single Wall Carbon Nanotubes

2003 ◽  
Author(s):  
R. P. Raffaelle ◽  
B. Landi ◽  
T. Gennett ◽  
R. S. Morris ◽  
B. Dixon ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Direct Methanol Fuel Cells ◽  
Active Material ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Aspect Ratios

Novel carbon materials with nanometer dimensions are of potentially significant importance for a number of advanced technological applications. Currently, considerable interest exists in the possible applications of single wall carbon nanotubes (SWNTs) to proton exchange membrane (PEM) fuel cells. Proposed uses include as anode materials in both hydrogen and direct methanol fuel cells, solid polymer electrolyte additives, active cathode materials and bipolar plate interconnects. One of the desirable attributes afforded by the use of SWNTs in fuel cell applications stems from a combination of their extremely high electrical conductivity and large aspect ratios which results in a low weight percent for the electrical percolation threshold. This conductivity combined with the outstanding catalytic surface area offered by these nanostructured materials makes them a potentially outstanding active material for PEM electrodes. In addition, the high thermal conductivity, enhanced mechanical properties and corrosion resistance of polymer-SWNT composites may play a large role in developing new fuel cell designs such as thin-film microelectronic fuel cells. We will review the current applications involving SWNTs in PEM fuel cells and report on the recent work in the Nanopower Research Lab at RIT and it partners on utilizing high purity SWNT’s in microelectronic fuel cells.

Thermodynamic Analysis of the Performance of an Irreversible PEMFC

2018 ◽  
Vol 388 ◽  
pp. 350-360 ◽  
Author(s):  
Chang Jie Li ◽  
Ye Liu ◽  
Zhe Shu Ma
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Controllable Factors ◽  
Temperature Operating ◽  
Exchange Membrane

An irreversible model of proton exchange membrane fuel cells working at steady-state is established, in which the irreversibility resulting from overpotentials, internal currents and leakage currents are taken into account．In this paper, the irreversibility of fuel cell is expounded mainly from electrochemistry. The general performance characteristic curves are generated including output voltage, output power and output efficiency. In addition, the irreversibility of a class of PEMFC is studied by changing the operating conditions (controllable factors) of the fuel cell, including effect of operating temperature, operating pressure and leakage current. The results provide a theoretical basis for both the operation and optimal design of real PEM fuel cells．

scholarly journals Experimental Studies of Effect of Land Width in PEM Fuel Cells with Serpentine Flow Field and Carbon Cloth

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 471 ◽  
Author(s):  
Xuyang Zhang ◽  
Andrew Higier ◽  
Xu Zhang ◽  
Hongtan Liu
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Flow Field ◽  
Pem Fuel Cells ◽  
Carbon Cloth ◽  
Pumping Power ◽  
Inlet Flow ◽  
Flow Rates ◽  
Reactant Flow ◽  
Land Width

Flow field plays an important role in the performance of proton exchange membrane (PEM) fuel cells, such as transporting reactants and removing water products. Therefore, the performance of a PEM fuel cell can be improved by optimizing the flow field dimensions and designs. In this work, single serpentine flow fields with four different land widths are used in PEM fuel cells to study the effects of the land width. The gas diffusion layers are made of carbon cloth. Since different land widths may be most suitable for different reactant flow rates, three different inlet flow rates are studied for all the flow fields with four different land widths. The effects of land width and inlet flow rate on fuel cell performance are studied based on the polarization curves and power densities. Without considering the pumping power, the cell performance always increases with the decrease in the land width and the increase in the inlet flow rates. However, when taking into consideration the pumping power, the net power density reaches the maximum at different combinations of land widths and reactant flow rates at different cell potentials.

Development of an Optical Sensor for Temperature Measurement and Water Droplet Detection in PEMFC Gas Channels

2011 ◽  
Author(s):  
Kristopher Inman ◽  
Xia Wang ◽  
Brian Sangerozan
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Temperature Measurement ◽  
Water Droplet ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Droplet Movement ◽  
Temperature Measurement System

Thermal and water management in Proton Exchange Membrane (PEM) fuel cells provide a significant challenge for engineers and fuel cell designers as both have a direct effect on performance and durability. Internal temperature is very difficult to measure due to component geometry and the internal environment possessed by PEM fuel cells along with a lack of sufficient temperature measurement methods which are often highly invasive. This research presents initial developments for creating a non-intrusive temperature measurement system, based on the principles of phosphor thermometry, which also has the ability to optically detect liquid water formation and movement in PEMFC gas channels. The sensor was designed, calibrated and then installed in a 25 cm2 PEM fuel cell for in-situ testing. The experimental data show that a relationship exists between temperature variation and water droplet movement in gas channels of a PEM fuel cell.

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