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8/17/2019 ME165-1_Week-9.1 Fuel Cells_621865.pdf
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ME165-1
ALTERNATIVE ENERGY RESOURCES
EWeek-9.1 Fuel Cells
2015-2016 / 3T
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Fuel Cells
What is a fuel cell?
A fuel cell is a device that converts the chemical energy fro
into electricity through a chemical reaction with oxygen or
oxidizing agent.
Hydrogen is the most common fuel, but hydrocarbons suc
gas and alcohols like methanol are sometimes used. Fuel cells are different from batteries in that they require a
source of fuel and oxygen to run, but they can produce ele
continually for as long as these inputs are supplied.
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Fuel Cells
Fuel Cell Welsh Physicist William Grove developed the first crude fu
1839.
The first commercial use of fuel cells was in NASA space p
generate power for probes, satellites and space capsules. S
fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for com
industrial and residential buildings and in remote or inacce
They are used to power fuel cell vehicles, including automo
buses, forklifts, airplanes, boats, motorcycles and submarine
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Fuel Cells
History of fuel cells
The principle of the fuel cell was discovered by German sci
Christian Friedrich Schönbein in 1838 and published in one
scientific magazines of the time.
Based on this work, the first fuel cell was demonstrated by a
scientist and barrister Sir William Robert Grove in the Febredition of the Philosophical Magazine and Journal of Science
sketched, in 1842, in the same journal.
The fuel cell he made used similar materials to today's phos
fuel cell.
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Fuel Cells
History of fuel cells (cont’d.)
In 1955, W. Thomas Grubb, a chemist working for the GeneCompany (GE), further modified the original fuel cell design
sulphonated polystyrene ion-exchange membrane as the ele
Three years later another GE chemist, Leonard Niedrach, d
way of depositing platinum onto the membrane, which serv
catalyst for the necessary hydrogen oxidation and oxygen r
reactions. This became known as the "Grubb-Niedrach fuel
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Fuel Cells
History of fuel cells (cont’d.)
GE went on to develop this technology with NASA and MAircraft, leading to its use during Project Gemini. This was
commercial use of a fuel cell.
In 1959, British engineer Francis Thomas Bacon successfull
a 5 kW stationary fuel cell.
In 1959, a team led by Harry Ihrig built a 15 kW fuel cell t
Allis-Chalmers, which was demonstrated across the U.S. at
This system used potassium hydroxide as the electrolyte a
compressed hydrogen and oxygen as the reactants.
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Fuel Cells
History of fuel cells (cont’d.)
Later in 1959, Bacon and his colleagues demonstrated a pr
kilowatt unit capable of powering a welding machine.
In the 1960s, Pratt and Whitney licensed Bacon's U.S. paten
in the U.S. space program to supply electricity and drinking
(hydrogen and oxygen being readily available from the spac
tanks).
In 1991, the first hydrogen fuel cell automobile was develo
Roger Billings.
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Fuel Cells
History of fuel cells (cont’d.)
United Technologies Corporation's UTC Power subsidiary
first company to manufacture and commercialize a large, s
fuel cell system for use as a co-generation power plant in
universities and large office buildings.
UTC Power marketed their fuel cell, the PureCell 200, asystem, now replaced by a 400 kW version, the PureCel
400.
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Fuel Cells
History of fuel cells (cont’d.)
UTC Power continues to be the sole supplier of fuel cel
for use in space vehicles, having supplied fuel cells for the
missions, and the Space Shuttle program, and is developi
for automobiles, buses, and cell phone towers.
The company has demonstrated the first fuel cell capable
under freezing conditions with its proton exchange mem
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Fuel Cells
Fuel Cells Design
Fuel cells come in many varieties; however, th
work in the same general manner.
They are made up of three adjacent segments
the anode, the electrolyte, and
the cathode.
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Fuel Cells
Block diagram of a fuel cell
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Fuel Cells
Fuel Cells Design (cont’d.)
Two chemical reactions occur at the interfaces of tdifferent segments.
The net result of the two reactions is that fuel is co
water or carbon dioxide is created, and an electric
created, which can be used to power electrical devnormally referred to as the load.
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Fuel Cells
Fuel Cells Design (cont’d.)
At the anode a catalyst oxidizes the fuel, usually hydrogen,fuel into a positively charged ion and a negatively charged
The electrolyte is a substance specifically designed so ions
through it, but the electrons cannot. The freed electrons tr
through a wire creating the electric current. The ions trave
the electrolyte to the cathode.
Once reaching the cathode, the ions are reunited with the
and the two react with a third chemical, usually oxygen, to
water or carbon dioxide.
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Fuel Cells
Most important design features in a fuel cell
The electrolyte substance. The electrolyte substance usualthe type of fuel cell.
The fuel that is used. The most common fuel is hydrogen.
The anode catalyst, which breaks down the fuel into elect
ions. The anode catalyst is usually made up of very fine pla
powder.
The cathode catalyst, which turns the ions into the waste
like water or carbon dioxide. The cathode catalyst is often
of nickel but it can also be a nanomaterial-based catalyst.
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Fuel Cells
To deliver the desired amount of energy, the fuel cel
combined in series and parallel circuits, where serieshigher voltage, and parallel allows a higher current to
supplied. Such a design is called a fuel cell stack. The
surface area can be increased, to allow stronger curr
each cell.
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Fuel Cells
Types of fuel cells design Proton Exchange Membrane Fuel Ce Solid Oxide Fuel Cell
Alkaline Fuel Cell
Molten Carbonate Fuel Cell
Phosporic Acid Fuel Cell
Direct Methanol Fuel Cell
Electro-galvanic Fuel Cell
Microbial Fuel Cell
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Fuel Cells
Proton Exchange Membrane Fuel Cell
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Fuel Cells
Solid Oxide Fuel Cell
The chemical reactions for the SOFC system can be expr
as follows:
Anode Reaction: 2H2 + 2O2− → 2H2O + 4e−
Cathode Reaction: O2 + 4e – → 2O2−
Overall Cell Reaction: 2H2 + O2→
2H2O Oxygen gas is fed through the cathode, where it reacts w
electrons to create oxygen ions.
The oxygen ions then travel through the electrolyte to re
with hydrogen gas at the anode.
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Fuel Cells
Solid Oxide Fuel Cell (cont’d.)
The reaction at the anode produces electricity and
by-products. Carbon dioxide may also be a by-prod
depending on the fuel, but the carbon emissions fro
SOFC system are less than those from a fossil fuel
combustion plant.
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Fuel Cells
Molten Carbonate Fuel Cell
The chemical reactions for the MCFC system can be exprfollows:
Anode Reaction: CO32− + H2 → H2O + CO2 + 2e−
Cathode Reaction: CO2 + ½O2 + 2e− → CO32−
Overall Cell Reaction: H2 + ½O2→
H2O The hydrogen in the gas reacts with carbonate ions from t
electrolyte to produce water, carbon dioxide, electrons an
amounts of other chemicals.
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Fuel Cells
Molten Carbonate Fuel Cell (cont’d.)
The electrons travel through an external circuit celectricity and return to the cathode.
There, oxygen from the air and carbon dioxide r
from the anode react with the electrons to form
carbonate ions that replenish the electrolyte, comthe circuit.
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Fuel Cells
Fuel cell name Electrolyte Qualified
power (W)
Working
temperature
(°C)
Efficiency
(cell)
Efficiency
(system)
Status Cost (U
Electro-galvanic fuel cell Aqueous alkaline
solution
39 !< 40 Commercial /
Research
Microbial fuel cell Polymer membrane
or humic acid
39 !< 40 Research
Alkaline fuel cell Aqueous alkaline
solution
10000 !10 –
100 kW
79 !< 80 65% !60 –
70%
62% Commercial /
Research
Direct methanol fuel cell Polymer membrane
(ionomer)
0.1 !100
mW – 1 kW
105 !90 – 120 25% !20 –
30%
15% !10 – 20% Commercial /
Research
1
Proton exchange
membrane fuel cell
Polymer membrane
(ionomer)
100 !100 W
– 500 kW
125 !50 – 120
(Nafion)125 – 220 (PBI)
60% !50 –
70%
40% !30 – 50% Commercial /
Research
50 –
Phosphoric acid fuel cell Molten phosphoric
acid (H3PO4)
999999 !<
10 MW
175 !150-200 55% 40% !40%
Co-Gen: 90%
Commercial /
Research
4 –
Molten carbonate fuel cell Molten alkaline
carbonate
100000000
!100 MW
625 !600 – 650 55% 47% Commercial /
Research
Tubular solid oxide fuel
cell (TSOFC)
O2--conducting
ceramic oxide
99999999 !<
100 MW
975 !850 – 1100 63% !60 –
65%
57% !55 – 60% Commercial /
Research
Direct carbon fuel cell Several different 775 !700 – 850 80% 70% Commercial /
Research
Planar Solid oxide fuel cell O2--conductingceramic oxide
99999999 !<100 MW
975 !500 – 1100 63% !60 – 65%
57% !55 – 60% Commercial /Research
Comparizon of Fuel Cell Types
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Fuel Cells
Three Most Common Applications of Fuel
Power
Cogeneration
Fuel cell electric vehicles (FCEVs)
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Applications of Fuel Cells
Power
Stationary fuel cells are used for commercial, indus
residential primary and backup power generation.
Fuel cells are very useful as power sources in remo
locations, such as spacecraft, remote weather statio
parks, communications centers, rural locations incluresearch stations, and in certain military application
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Applications of Fuel Cells
Power (cont’d.)
A fuel cell system running on hydrogen can be comlightweight, and have no major moving parts. Becau
cells have no moving parts and do not involve comb
ideal conditions they can achieve up to 99.9999% re
This equates to less than one minute of downtime year period.
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Applications of Fuel Cells
Cogeneration
Combined heat and power (CHP) fuel cell systemsMicro combined heat and power (MicroCHP) syst
used to generate both electricity and heat for hom
home fuel cell), office building and factories.
The system generates constant electric power (seexcess power back to the grid when it is not consu
and at the same time produces hot air and water f
waste heat. MicroCHP is usually less than 5 kWe fo
fuel cell or small business.
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Applications of Fuel Cells
Cogeneration (cont’d.)
The waste heat from fuel cells can be diverted durisummer directly into the ground providing further
while the waste heat during winter can be pumped
into the building. The University of Minnesota owns
patent rights to this type of system.
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Applications of Fuel Cells
Fuel cell electric vehicles (FCEVs)
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Applications of Fuel Cells
Other Applications
Providing power for base stations or cell sites.
Distributed generation.
Emergency power systems, are a type of fuel cell system, w
include lighting, generators and other apparatus, to provide
resources in a crisis or when regular systems fail. They findwide variety of settings from residential homes to hospital
laboratories, data centers, telecommunication equipment a
modern naval ships.
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Applications of Fuel Cells
Other Applications (cont’d.)
An uninterrupted power supply (UPS) provides empower and, depending on the topology, provide line
regulation as well to connected equipment by supp
power from a separate source when utility power i
available. Unlike a standby generator, it can provide protection from a momentary power interruption.
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Applications of Fuel Cells
Other Applications (cont’d.)
Base load power plants. Fuel cell APU for Refuse Collection Vehicle.
Hybrid vehicles, pairing the fuel cell with either an ICE or
Notebook computers for applications where AC charging
be readily available.
Portable charging docks for small electronics (e.g. a belt cl
charges your cell phone or PDA).
Smartphones, laptops and tablets.
Small heating appliances.
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Textbooks
Renewable Energy Technologies, Jean-Claude Sabonnadiere, 2009 Energy Conversion, D. Yogi Goswami, Frank Kreith, 2008
Power Plant Engineering, 3rd Edition, PK Nag, 2008, Tata McGraw Hi
Web http://en.wikipedia.org/wiki/Fuel_cell
References
http://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cellhttp://en.wikipedia.org/wiki/Fuel_cell