Alga Science SOLARCOASTER, Руководство пользователя

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IntroductIon
The solar Science series demonstrate the use of
solar energy in our daily lives. You will see sunlight
provides the energy to drive different models like
cars and boat. However, you need to have patience
in building these models and follow the instructions
step by step to make them work. Most important of
all, they need to be illuminated with either strong
sunlight or closely under a bright lamp. Your hard
work will be compensated when you see your
models finally work without batteries!
All these models make use of solar cells to
provide the necessary power. Sunlight falling on
the solar cells is converted into electric current. This
current drives the motors to provide the mechanical
power of movement or provide electricity to the
radio or music box circuit boards. In commercial
applications a large number of solar cells are
connected together to provide enough electricity to
power demanding devices like solar vehicle or street
light. A rechargeable battery is often used to store
the electricity in daytime and release the current at
night or when required.
What kInd of lIght Is requIred?
The best light source for these models are strong
bright sunlight, you can take them outdoors on a
sunny day or place them near the window where
there is sunlight. When playing outdoors, be careful
and wear suitable protective clothing and hat to
protect yourself from the sun’s ultraviolet radiation.
Alternatively, these models will also work under
a bright lamp of at least 60 watts. You will need to
put it close to the lamp (less than 10cm) to provide
sufficient illumination. Try putting the model at
different distance from the lamp, what happens?
The model will move slower (or sound weaker in case
of a radio model) and eventually stop working when
you move it further and further away from the light
because less light is falling on the solar cell.
Caution!
Be very careful not to touch the bulb or
you will get burnt! Keep a distance from the light.
You can experiment with different types of light
source to see which is the most efficient. As you will
find out, those energy saving lamps and fluorescent
tubes are not bright enough to power these models.
• Sunlight
• Sunlight through the window
• Lamp
the sun and solar energy
The sun is 150 million kilometres from the earth
and is 4 to 5 billion years old. The temperature of
the sun ranges from 6000 degrees Celsius at its
surface to more than 6.5 million degrees Celsius at
its centre. That’s HOT! It takes about 8 minutes for
this energy to reach the earth. The sun itself is a star
made up of mostly hydrogen and helium gas and it
radiates an enormous amount of energy every day.
The sun is the ultimate source of all energy on
earth. Without it the lives on earth would not exist,
there will not be any fossil fuel (e.g. coal and oil) for
us to use, which comes from the decaying plants
hundreds of millions of years ago. We use the sun’s
energy everyday in many different ways. When we
hang our laundry outside to dry in the sun, we are
using the heat from the sun to do the work. Plants use
sunlight to produce food. Animals eat plants for food.
330 Million Terawatt hours
(330000 000000000000000 watt-hour!) of
equivalent energy from the sun hits the earth every
year. That’s 30 times more energy from the sun in a
single year than all the energy stored in the earth.
If we can use more solar energy, which is clean and
practically inexhaustible, we will be less dependent
on fossil fuels. Burning fossil fuels produce green
house gas and other pollutants which are harmful
to our environment. There are two ways to convert
solar energy into electricity: Solar thermal electricity
and Solar Cells. The former use the suns heat to boil
water and drive a turbine to generate electricity. The
latter convert sunlight directly into electricity.
solar cells or
PhotovoltaIc energy
Solar cells are also called photovoltaic cells - or PV
cells for short. They can be found on many small
appliances, like watches, calculators, and even on
spacecraft. They were first developed in the 1950s
to provide power for the satellites in space. They are
made of silicon, a special type of melted sand.
Photovoltaic systems are solar systems that
produce electricity directly from sunlight. The term
”photo” comes from the Greek ”phos,” meaning
light. ”Voltaic” is named for Alessandro Volta
(1745-1827), a pioneer in the study of electricity for
whom the term ”volt” was named. Photovoltaics,
then, means ”light electricity.” Photovoltaic
systems produce clean, reliable electricity without
consuming any fossil fuels. There is no fuel, steam
or thermodynamics involved. They are being used
in a wide variety of applications, from providing
power for watches, highway signs, and space
stations, to providing for a household’s electrical
needs. The industry has been growing steadily at a
rate of at least 25% per year for the past 20 years.
It is estimated that by the year 2020, more than
30 millions household will be powered by solar
electricity.
Most photovoltaic cells are made from a
crystalline substance called silicon, one of the
Earth’s most common materials. Solar cells are
typically made by slicing a large crystal of silicon
into thin wafers and putting two separate wafers
with different electrical properties together, along
with wires to enable electrons to travel between
layers. When sunlight hits the wafers, electrons
naturally travel from one layer to the other through
the wire because of the different properties of each
layer, resulting in the release of electricity.
These individual solar cells are arranged
together in a PV module and the modules are
grouped together in an array. Some of the arrays are
set on special tracking devices to follow sunlight all
day long.
The electrical energy from solar cells can then
be used directly. It can be used in a home for lights
and appliances. It can be used in a business. Solar
energy can be stored in batteries to light a roadside
billboard at night. Or the energy can be stored
in a battery for an emergency roadside cellular
telephone when no telephone wires are around.
Some experimental cars also use PV cells. They
convert sunlight directly into energy to power
electric motors on the car.
Basic Structure of a Solar Cell
Positiv Layer
Diversion Layer
Negative Layer
Flow of Electrons Light