Download Fuel cells - engineeringtechnology

By: Adam B and Marshall L
 What
are the different types
of fuel cells? Compare,
Contrast and describe at least
three.

1. Hydrogen Fuel Cell*
2. Proton Exchange Membrane Fuel Cell
3. High-temperature PEM
4. Direct Methanol Fuel Cell
5. Alkaline Fuel Cell*
6. Phosphoric Acid Fuel Cell
7. Molten Carbonate Fuel Cell
8. Solid Oxide Fuel Cells
9. Regenerative Fuel Cells*
10. Zinc Air Fuel Cells*
11. Microbial Fuel Cells*
A fuel cell combines hydrogen and oxygen to produce
electricity, heat, and water. Fuel cells are often compared to
batteries. Both convert the energy produced by a chemical reaction
into usable electric power. However, the fuel cell will produce
electricity as long as fuel (hydrogen) is supplied, never losing its
charge.

Alkaline fuel cells (AFCs) were one of the first fuel cell
technologies developed, and they were the first type widely used
in the U.S. space program to produce electrical energy and water
on-board spacecraft. These fuel cells use a solution of potassium
hydroxide in water as the electrolyte and can use a variety of nonprecious metals as a catalyst at the anode and cathode.

A regenerative fuel cell or reverse fuel cell (RFC) is a fuel cell run
in reverse mode, which consumes electricity and chemical B to
produce chemical A. By definition, the process of any fuel cell
could be reversed. However, a given device is usually optimized
for operating in one mode and may not be built in such a way that
it can be operated backwards. Standard fuel cells operated
backwards generally do not make very efficient systems unless
they are purpose-built to do so as with high-pressure
electrolyzers.

Zinc Air Fuel Cells (ZAFCs) combine zinc pellets and air with an
electrolyte to create electricity, generating significantly more
power than lead-acid batteries of the same weight. ZAFC systems
have potential use in transport applications.

Microbial Fuel Cells (MFCs) use the catalytic reaction of
microorganisms to convert virtually any organic matter (e.g.
glucose, acetate, wastewater) into fuel. Enclosed in oxygen-free
anodes, organic compounds are consumed by bacteria or other
microbes. As part of the digestive process, electrons are pulled
from the fuel and conducted into a circuit with the help of
inorganic mediator chemicals. MFCs operate in mild conditions
between 68-104⁰F. These systems are capable of efficiencies up to
50 percent, and will be suitable for small to miniature applications
such as medical devices.
The Hydrogen, Zinc and Alkaline Fuel Cells are
similar because they all create energy. Another
way that these fuel cells are similar is they all
work in quite similar ways.

The Hydrogen, Alkaline and Zinc Fuel Cells
are different because they use different things
to make them run. The Hydrogen Fuel Cell
takes hydrogen and oxygen, the Alkaline Fuel
Cell uses potassium and hydroxide, whereas
the Zinc Fuel Cell combines zinc pellets with
air.

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http://energy.gov/eere/fuelcells/types-fuelcells
http://www.renewableenergyworld.com/rea/
tech/hydrogen
http://www.fuelcells.org/base.cgim?template
=types_of_fuel_cells
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http://butane.chem.uiuc.edu/pshapley/Enlist
/Labs/FuelCellLab/FuelCell.html
http://en.wikipedia.org/wiki/Fuel_cell
http://www.afcenergy.com/technology/how_
an_alkaline_fuel_cell_works.aspx
http://www.prototech.no/index.cfm?id=2234
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http://www.cnet.com/news/zinc-fuel-cellmaker-readies-portable-power-pack/