صفحه 1:
Solar Energy:
The Ultimate
Renewable
۳۵۱۷۵۲ 1۲۵۴۱ ۱۱۵ ۰
Bhavik Shah
صفحه 2:
What is Solar Energy?
= Originates with the
ل عمط
fusion reactions
occurring in the sun.
= Represents the
عشاصه
electromagnetic
اا
light, infrared,
ultraviolet, x-rays,
and radio waves).
صفحه 3:
Advantages and
* Advantage Disadvantages
= All chemical and radioactive اس
byproducts of the thermonuclear reactions
remain behind on the sun, while only pure
radiant energy reaches the Earth.
= Ener laa the earth is incredible. By one
calculation, 30 days of sunshine striking the
Earth have the energy equivalent of the total of
all the planet’s fossil fuels, both used and
unused!
= Disadvantages
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= Solar energy is a diffuse source. To harness it,
we must concentrate it into an amount and
form that we can use, such as heat and
3 ایا وت
= Addressed by approaching the problem
through:
1) collection, 2) conversion, 3) storage.
صفحه 4:
The surface receives about 47% of the
total solar energy that reaches the
Earth. Only this amount is usable.
صفحه 5:
Putting Solar Energy to
Use: Heating Water
Two methods of ات
water: passive (no moving
parts) and active (pumps).
In both, a flat-plate
collector is used to absorb
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the water.
The water circulates
throughout the closed
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currents.
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used as storage.
صفحه 6:
صفحه 7:
Heating Water—Last
Efficiency of Pe Mokena cy knee Catv
100% because:
= % transmitted depends on angle of incidence,
=" Number of glass sheets (single glass sheet
transmits 90-95%), and
= Composition of the glass
Solar water heating saves approx. 1000 megawatts of
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from two medium sized coal burning power plants.
By using solar water heating over gas water heater, a
family will save 1200 pounds of pollution each year.
Market for flat Ae collectors grew in 1980s because of
increasing fossil fuels prices and federal tax credits.
But by 1985, when these credits were removed and fossil
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shrunk quickly.
While solar water heating is relatively low in the US, in
other parts of the world such as Cyprus (90%) and Israel
aes Tee ار
eating.
صفحه 8:
Heating Living Spaces
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collector and storage unit. This is achieved
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storage.
Efficient heating starts with proper insulation on
external walls, roof, and the floors. The doors,
windows, and vents must be designed to minimize
heat loss.
Collection: south-facing windows and appropriate
landscaping.
Storage: Thermal mass—holds heat.
Water= 62 BTU per cubic foot per degree F. "=
=Tron=54, Wood (oak) =29, Brick=25,
concrete=22, and loose stone=20
صفحه 9:
صفحه 10:
Heating Living Spaces
= A passively heated home uses about 60-
75% of the solar energy that hits its walls
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= The Center for Renewable Resources
estimates that in almost any climate, a
well-designed passive solar home can
reduce energy bills by 75% with an added
construction cost of only 5-10%.
LV ae soh MRR CMC CO MNCL acs li ted
space heating.
= Major factor discouraging solar heating is
low energy prices.
صفحه 11:
(۰۱ ۱۱09۱۱۱۰۱ مهافت
Power Towers
General idea is to collect the light from many reflectors
spread over a large area at one central point to achieve
high temperature.
Example is the 10-MW solar power plant in Barstow,
= 1900 heliostats, each 20 ft by 20 ft
=a central 295 ft tower
An energy storage system allows it to generate 7 MW of
ره ان Cette
Capital cost is greater than coal fired power plant,
despite the no cost for fuel, ash disposal, and stack
emissions.
Capital costs are expected to decline as more and more
power towers are built with greater technological
advances.
One way to reduce cost is to use the waste steam from
the turbine for space heating or other industrial
processes.
صفحه 12:
Power Towers
Power tower in Barstow,
California.
صفحه 13:
Solar-Thermal Electricity:
Parabolic Dishes and Troughs
=" Focus sunlight on a smaller receiver for each
device; the heated liquid drives a steam
engine to generate electricity.
= The first of these Solar Electric Generating
Stations (SEGS) was installed in CA by an
Israeli company, Luz International.
= Output was 13.8 MW; cost was $6,000/peak
kW and overall efficiency was 25%.
= Through federal and state tax credits, Luz was
able to build more SEGS, and improved
reduced costs to $3,000/peak kW and the cost
اعم عاطعه 8 0غ علوعه 25 ددم واأعتجاععاء 1ه
kWh, barely more than the cost of nuclear or
coal-fired facilities.
= The more recent facilities converted a
remarkable 22% of sunlight into electricity.
صفحه 14:
صفحه 15:
Photovoltaic cells are capable
of directly converting
sunlight into electricity.
A simple wafer of silicon with
wires attached to the layers.
Current is produced based on
types of silicon (n- and p-
types) used for the layers.
Each cell=0.5 volts.
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No moving parts>do no wear
out, but because they are
exposed to the weather, their
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صفحه 16:
Solar Panels in Use
= Because of their current costs,
only rural and other customers
far away from power lines use
solar panels because it is more
cost effective than extending
power lines.
» عتته دعتسدمحصم جاتلتأنت أقط) عأوتح
already purchasing, installing,
and maintaining PV-home
systems (Idaho Power Co.).
= Largest solar plant in US,
sponsored by the DOE, served
the Sacramento area, producing,
2195 MWh of electric energy,
making it cost competitive with
fossil fuel plants.
صفحه 17:
Efficiency and
Disadvantages
« حصمظ جاتمتتا‌عاه که اووی 021-
burning plants is anywhere
ie -20 cents/kWh,
while photovoltaic power
jeneration is anywhere b/w
ECS TTA
= Does not reflect the true
costs of burning coal and its
ات
nonpolluting method of the
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* Underlying problem is
weighing efficiency against
5
= Crystalline silicon-more
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to manufacture
و totes cies rte ey
efficient, less expensive to
0
۱:۰ و راتس
than the 77% of solar
spectrum with usable
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43% of photon energy is
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crystal.
Efficiency drops as
temperature increases
(from 24% at 0°C to 14%
at 100°C.)
Light is reflected off the
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و را ا ا
other factors.
Overall, the efficiency is
about 10-14%.
صفحه 18:
Final Thought
عمصعيسل تدده تتععدمم 22011065 صتاك أقطع لجع سوسم
the day is countered by the fact that 70% of
energy demand is during daytime hours. At
night, traditional methods can be used to
generate the electricity.
Goal is to decrease our dependence on fossil
fuels.
Currently, 75% of our electrical power is
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1
Mitigates the effects of acid rain, carbon dioxide,
and other impacts of burning coal and counters
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صفحه 19:
The End