3. Solar energy is heat and radiant light from the
Sun that can be harnessed with technologies
such as solar power (which is used to
generate electricity) and solar thermal energy
(which is used for applications such as water
heating).
What is solar energy?
4. Originates with the thermonuclear fusion
reactions occuring in the sun.
Represents the entire electromagnetic radiation
(visible light, infrared, ultraviolet, x-rays and
radio waves).
Radiant energy from the sun has powered life
on Earth for many million years.
What is solar energy?
5. Sunlight is the largest energy source to reach the
Earth but, despite this, the intensity of the energy
that reaches the Earth’s surface is relatively low
due to the radial spreading of solar radiation as it
travels from the distant Sun. More of this sunlight
is lost in the Earth’s atmosphere and due to
clouds, which between them scatter as much as
54% of the incoming light.
How Does Solar
Energy Work?
7. 1.THERMAL ENERGY
It is everywhere. It lights up our days. It
heats the earth, our bodies and homes. It
dries our clothes. All for free.
2.ELETRIC ENERGY
Energy uses the power of the sun to produce
electricity through solar cells, otherwise
known as photovoltaics(PV).
8. PHOTOVOLTAICS
Photo + Voltaic = convert light to energy
The Sun can be used to generate electricity using photovoltaics (PV) and
concentrated solar power. Photovoltaic cells, commonly known as solar
cells, turn light into an electric current while concentrated solar power
involves the use of mirrors, lenses and solar tracking systems to focus
sunlight into a small beam.
9.
10. Thermal energy conversion can be achieved with solar ponds.
These are bodies of salt water that collect and store solar energy
which can be used to produce products like chemicals, food and
textiles, as well as being used to warm greenhouses, swimming
pools and livestock buildings. Solar ponds can also be used to
produce electricity using the organic Rankine cycle engine, but they
are fairly expensive to install and their use is generally limited to
warm rural locations.
11. Solar energy has already found a wealth of applications, whether based upon
thermal or electrical energy generation, or even on more passive uses of the
light and heat that reaches the Earth from the Sun each day…
EXAMPLES AND
APPLICATION
12. Sunlight can be used to heat water using
evacuated tube collectors, glazed flat plate
collectors and unglazed plastic collectors. Solar
hot water systems are widely deployed in China
and nations such as Israel and Cyprus lead the
world in per capita use, while Australia, Canada
and the United States mainly use solar water
heating to heat swimming pools.
1. WATER HEATING
13. 2. Cooling, Heating and Ventilation
Solar energy can be used on heating, cooling and ventilation.
Solar heating is divided into active and passive solar concepts
according to whether active elements like solar concentrating
optics or sun tracking are used. Thermal mass, which is any
material that can be used to store heat, is also used in arid or
warm temperate climates to keep buildings cool. These materials
include stone, cement or water, which absorbs solar energy during
the day and then radiates the warmth during the cooler night-time
hours. Solar or thermal chimneys can also be used for ventilation,
allowing air to heat up inside to create an updraft that pulls air
through a building, creating ventilation.
14. 3.COOKING
Solar cookers have been used for applications such as cooking,
drying and pasteurization for centuries. The first box cooker, which is
an insulated container with a transparent lid that can reach
temperatures of 90-150°C, was built by Horace de Saussure in
1767. Panel cookers also use an insulated container but include a
reflective panel to direct the sunlight and can reach similar
temperatures to box cookers. Reflector cookers use concentrating
geometries such as dishes, troughs or Fresnel mirrors to focus the
sunlight and can reach temperatures of 315°C, but require direct
light to work correctly and must be repositioned to track the
movement of the Sun.
15. 4. Process Heat
Technology to concentrate sunlight, such as
parabolic dishes, troughs and reflectors, are
used to provide process heat for a range of
industrial and commercial applications. This
includes heating, air conditioning, ventilation
and electricity generation.
16. 5. Water Treatment
Solar energy has been used for distillation since at least
the 16th Century to make brackish or saline water
potable. Along with desalination, sunlight is used for
disinfecting water. Solar water disinfection (SODIS) is
used by over two million people in developing countries
each day to make drinking water. Using sunlight to
evaporate water from shallow ponds is also a traditional
method of obtaining salt from seawater and can be used
to concentrate brine solutions or removing dissolved
solids from waste streams.
19. The Sun can be used to generate electricity using photovoltaics (PV) and
concentrated solar power. Photovoltaic cells, commonly known as solar
cells, turn light into an electric current while concentrated solar power
involves the use of mirrors, lenses and solar tracking systems to focus
sunlight into a small beam.
Electricity Generation Examples
20. Concentrated solar power (CSP) involves the use of lenses or mirrors to focus sunlight into a small
beam and tracking systems to follow the movement of the Sun. The heat of this beam is then used as
a heat source to heat a fluid to generate electricity (as with a conventional power plant, where water is
heated to create steam that turns turbines, which power an electricity generator). Technologies to
concentrate the sunlight include Fresnel reflectors, parabolic troughs, Stirling dishes and solar power
towers. CSP designs often need to be protected against weather events such as dust storms that can
damage the fine mirrored glass surfaces used at some solar power plants. This can be done by
installing metal grills that offer a level of protection while allowing sunlight to reach the mirrors.
Concentrated Solar Power
