Essay
unit 22 LAD Reducing carbon emissions for a sustainable future
- Module
- Unit 22 - Materials Science
- Institution
- PEARSON (PEARSON)
- distinction level -essay/ assignment physics
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BTEC Assignment BriefPearson BTEC Level 3 National Diploma in Applied Science
Qualification
Pearson BTEC Level 3 National Extended Diploma in Applied Science
Unit number and title Unit 22: Materials Science
D: Examine materials used in applications in order to reduce carbon
Learning aim
emissions for a sustainable future.
Assignment title Managing our ‘Carbon Footprint’
Assessor
Issue date
Hand in deadline
You are a volunteer for Friends of the Earth. You have been asked
to use your scientific training to produce a portfolio of case studies
that will demonstrate how materials are used in applications to
Vocational Scenario or
reduce carbon emissions. This portfolio will be used to encourage
Context
other organisations to employ technology to further reduce their
carbon emissions.
Using your lesson notes and research you have carried out into
applications that reduce carbon emissions, produce a portfolio of
case studies for Friends of the Earth.
Choose any THREE case studies from the following list to include in
your portfolio:
Polymers for electrolyte membranes and ceramic based
electrodes in fuel cells
Glass fibre composites and aluminium in wind turbine
Task blades
Silicon wafer and cadmium telluride in solar photovoltaic
cells
Allium arsenide (GaA) and gallium nitride in light-emitting
diodes (LEDs)
PORTFOLIO TASKS:
Task 1: For each case study chosen, highlight the key properties
of each material and provide information about the functionality
and suitability of the materials to explain how they can be used
to reduce global emissions.
Task 2: By highlighting their main features and factors, compare
the three different methods (wind turbines, fuel cells and solar
photovoltaic cells) used to reduce carbon emissions and explain
how/why they are used to reduce carbon emissions.
TASK 3: Explain why the different materials are used for the
methods given in the case studies.
1
BTEC Assignment Brief v1.0
BTEC Internal Assessment QDAM January 2015
, TASK 4: Evaluate the benefits and limitations of using each of
the materials for the applications in the case studies. You will
need to provide appropriate evidence on which to base your
conclusions.
Checklist of evidence A portfolio of three case studies which:
required Provides information about the functionality and suitability of
the materials to explain how they can be used to reduce
global emissions;
Compares the three different methods (wind turbines, fuel
cells and solar photovoltaic cells) used to reduce carbon
emissions;
Evaluates the benefits and limitations of using each of the
materials for the applications in the case studies.
Sources of information must be appropriately referenced.
Correct scientific terminology must be used.
Criteria covered by this task:
Unit/Criteria
To achieve the criteria, you must show that you are able to:
reference
Evaluate the benefits and limitations of using materials in order to reduce
D. D4
carbon emissions.
Compare methods used to reduce carbon emissions for materials used in given
D. M4
applications.
D. P6 Explain how materials can be used to reduce global emissions.
Sources of information
to support you with http://citeseerx.ist.psu.edu/viewdoc/download?
this Assignment doi=10.1.1.464.5842&rep=rep1&type=pdf
http://www.azooptics.com/Article.aspx?ArticleID=147
http://americanhistory.si.edu/fuelcells/basics.htm
http://spectrum.ieee.org/energywise/green-tech/fuel-cells/ge-
claims-fuel-cell-breakthrough-starts-pilot-production
http://eartheasy.com/live_energyeff_lighting.htm#led
Other assessment
materials attached to
this Assignment Brief
ASSIGNMENT TITLE: Managing our ‘Carbon Footprint’
Introduction: I am a volunteer of ‘Friends of earth’, and I am producing a portfolio of my studies of
cases that will show how certain special materials are used in applications to reduce carbon
emissions. From this portfolio I hope for people to be inspired and carry one researching and making
materials and technology to better our future and reduce our carbon emissions, since we are
currently destroying our own world with our damaging fuels and our sources of energy. I will be
2
basing my case studies on fuel cells, wind turbines and solar cells, and will be discussing which
materialBTEC
is Assignment Brief v1.0
used and discussing why as well.
BTEC Internal Assessment QDAM January 2015
Task 1:
Polymers for electrolyte membranes and ceramic based electrodes in fuel cells:
, - Portable applications, since it has a lower power density compared to PEM. Ceramic fuel cells
functionality is combining fuel and oxidant gases by an ionic conducting ceramic. The solid
metal oxide is an insulator that does not conduct electricity but can conduct oxygen ions,
making it suitable for fuel cell electrolytes. Ceramics are hard and have obvious advantages
over all other types of fuel cells. [(5) www.sciencedirect.com]. Ceramic based electrolytes have
an efficiency rate approximately 40%. This is shows that it works great and can be great for the
environment since, it produces little-to no carbon emissions and would reduce the air pollution
when it comes to using this as a fuel resource for vehicles and other portable applications.
Glass fibre composites and aluminium in wind turbines blades:
- Wind energy works as a result of large movements moved by the air surrounding the blades,
driven by the sun. This is a result from kinetic energy in wind, making it a renewable energy
source for homes, industries and more. Wind turbines use kinetic energy from wind and
convert this into mechanical energy, which is then later converted to electrical energy, which
can be used wherever. The wind turbine is made up of three components; the tower, nacelle
and the rotor blades, which would be our main focus in this portfolio. These are all connected
together, as the blades are connected to the nacelle and that is connected to the generator. As
the pressure of the air hit against the blade, the kinetic energy is transferred into the blades,
which activated the generator. The shape of the blade allows the winds to go around it
smoothly, allowing the wind to be captured at lower velocities to increase the turbine
efficiency.
- glass fibre composites are widely used in wind turbine blades. This material is a fibrous, which
means that it is a natural substance and is known to be longer than wider and are known to be
flexible and be shaped into your desired shapes. Glass fibre composites have great stiffness
and strength of 330-370MPa. This is a desired characteristics for the blades, since it needs to
be durable when it faces the wind and the kinetic energy. However, since fibre can be delicate
and break easily, they cannot be used individually but instead as an additive reinforcement.
Glass fibre composites are made up of both SiO 2 and Al2O3. This would mean it is a stronger
material since it is an alloy, therefore harder to break. Glass fibres have moderate stiffness,
high strength, moderate density and the substance has an amorphous structure with isotropic
properties due to the lack of crystallographic order. This ensures that properties like stiffness
and thermal expansion are consistent in the fibre. They are also cheaper, are also used a lot in
this industry. The function of glass fibres used a lot for the blades since it has lots of desirable
properties that are suitable for this function of being a wind turbine.
- Aluminium is also used in the wind turbine blades. This material is a kind of silver/white
metallic fibre, meaning it is a good material when it comes to the blades. Wind turbines tend to
use aluminium alloys for their material, this is so it is stronger and durable and will not break
during its use. Since it is made up of ½ to 1/3 of aluminium, this would mean they can
transform the material to be thicker and strong and at the same time be light at weight. In
addition, it has a great and suitable density for the blades to be in the air with 2.70 g/cm 3. [(6)
www.pearson.com]. This is important to have an efficient turbine. In addition, aluminium is
resistant to corrosion from the atmosphere above, this is due to its inclination to form a layer of
oxide on the surface of the blade. [(7) www.sciencedirect.com]. Aluminium main function in
these turbines, is being light and also durable and strong in order to turn the kinetic energy
into electrical energy. Aluminium is also very suitable for this function, since it is weather-
resistant and will not mis-shape. [(8) www.thebackshed.com]. Aluminium is also a ‘green’
material, since it is recyclable and saves around 95% energy to make aluminium from the raw
source.
Silicon wafer and cadmium telluride in solar photovoltaic cells:
- The sun is the most renewable energy source we have, since we know that the sun will only
burn out in billions of years ahead of us. So as long as it shines on our planet, it will release
their energy onto us. The solar cell, also known as Photovoltaic (PV), is a device that allows
light energy to be adapted to electrical energy. We see these solar cells in solar panels,
which are used in farms, some homes, in calculators and more, since they generate a good
amount of electrical energy in order for the application to work. When light is shone onto the
solar cells, the light is either absorbed, passed through the cell or reflected. The PV cell is
made of semiconductor material, which conducts electricity better than an insulator but not
as well as a strong conductor such as a metal. When exposed to light, the semiconductor
absorbs the energy and transfers it to negatively charged particles in the material known as
electrons. This extra energy allows electrons to flow as an electrical current through the
material. This current is extracted via conductive metal contacts – the grid-like lines on3solar
BTEC –
cells Assignment
and used Brief
tov1.0
power your home and the rest of the electric grid. Solar cells are a great
BTEC Internal Assessment QDAM January 2015
renewable energy since it releases no carbon emissions and does not intensify the air
pollutions and the heat.
, - of their structure. Their structure consists of crystalline silicone cells, where the silicon atoms
are connected to one another to form a crystal lattice. This presents an organised structure
that makes conversion of light more efficient and to be stronger and durable when it comes to
its usage, so the material will not break or get damaged. Silicon wafers has a high efficiency
rate of over 25% for single-crystal cells and over 20% for multi-crystalline cells according to (9)
www.energy.gov. This is a desirable characteristic of the material to be used for the
photovoltaic cells, since it can produce electricity most of the time and at a required amount to
power their application that they are being used for. However, this is depending on where you
live, such as a sunny place or an area with little sun. So, having this depends on if you have
enough sun light for the silicon wafer to absorb. Silicon wafers also last for a lifetime. This is
because the crystalline structure of silicon lasts for 25 years without weakening. This is an ideal
property of silicon wafers since it is desired in industrial solar power generation. Silicon wafers
tend to be more expensive compared to other material of other material in solar cells, but it is
low-cost material compared to natural gas and other major powers sources. Silicon wafers
function in solar cells is that they can convert light energy to electrical efficiently which is
possible since it has a structured lattice in order for it to work.
- Cadmium telluride, also known as CdTe is the second most commonly used material for PV
after silicon. Cadmium telluride Is an insoluble material, this means that CdTe cannot be
dissolved and therefore a great material when it comes to it durability and stability. CdTe has a
high melting point of 1092 degrees, this means it has a strong and stable crystalline
compound, the atoms are also covalently bonded too – which is the strongest bond. With this
you can see that the melting point would need to be high in order to break these bonds and the
crystalline structure of cadmium telluride. This also goes to their boiling point which is also high
with 1130 degrees. The thermal conductivity is at 6.2 W/m.k, which is a good thing since it
means it can conduct the heat from the sun and the light energy it is emitting. The production
efficiency rate is high and the solar cells being cheaper than silicon wafer PV. Cadmium
telluride function as the material of the solar cell is good since it has the desired properties in
order to fit the criteria and it is also suitable to be the solar cells, from its price to its boiling
point. [(10)www.chemistrylearner.com].
Task 2:
WIND TURBINES:
Wind turbines when it comes to reducing carbon emissions, they rely on the wind adding kinetic
energy onto the blades making it spin and turning on the generator and turning it into mechanical
energy and then electrical energy. This process helps reduce carbon emissions by using no
greenhouse gases that could possibly contribute to air pollutions and global warmings. This method is
used instead since wind is renewable energy and will never run out. So, we are using this as our
advantage and making energy out of this, as this is way safer to use to power our homes, our
electronics and more, which will be running constantly since there is always wind. This method
displaces greenhouse gas emissions by generating electricity by the wind every kilowatt per hour.
This otherwise would have been replaced by fossil fuels such as coal, oil and gas.
[(11)www.communitywindpower.co.uk]. Compare to fuel cells, which rely on electricity energy
produced by chemical reactions, fuel cells are also a renewable energy and the only by product from
this chemical reaction is water, since it does not include combustion. However, fuel cells tend to have
a problem when it comes to disposing the electrodes, since it is less durable compared wind turbines,
so they are not as long lasting. There are also safety concerns since it uses hydrogen, since it is
highly flammable. Whereas wind turbines are not in danger, and they are long lasting, since the
blades are resistant to corrosion. Comparing wind turbines to solar cells is that solar cells tend to
depend on the sun a lot, so it would be preferred if they are placed in a sunny area, if they are placed
somewhere that has an inconsistent weather, it can cause the generator to make less electricity,
therefore the solar cells to have an inefficiency. Whereas wind turbines can be used anywhere since
wind is constant even if there is weather that is very warm. Therefore, there is a high efficiency rate
with wind turbines. [(12)www.ecavo.com].
FUEL CELLS:
Fuel cells when it comes to reducing carbon emissions, they displace the amount of greenhouse
emissions by making electricity energy from chemical reactions that does not include combustion.
The only thing that is resulted from this reaction is water as the by product and no carbon emissions.
Fuel cells are used mostly used when it comes to cars, battery powered cars, emergency backup
power applications, portable applications and more. This method is quite efficient as long as we have
hydrogen and oxygen to be used for the chemical reactions. Comparing this to wind turbines, wind
turbines use the wind, which is always around, whereas fuel cells use two substances to 4make a
manmade BTECchemical reaction
Assignment Brief v1.0 in order to convert to electrical energy. Wind turbines are prone to
contribute
BTECto noiseAssessment
Internal pollutionQDAMwithJanuary
its huge
2015 size and its generator giving of sound. In addition, it can be
problem when it comes to installation, since it takes up a lot of space of the land it is in. on the other
hand, fuel cells tend do not contribute to noise pollution since it is in an area where you cannot hear
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