Transcript Document

APPLICATIONS OF SOLAR
TECHNOLOGY
Solar thermal collectors
Solar and photovoltaic cells
Photovoltaic panels
Photovoltaic performance
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WHAT IS SOLAR ENERGY?
• Solar energy is the
radiant light and heat
from the sun which
has been harnessed
from humans since
ancient times using a
range of everevolving technologies.
• Only a minuscle part
of solar energy is
used.
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• Solar power technologies provide electrical
generation by means of heat engines or
photovoltaics. A partial list of solar
applications includes space heating and
cooling through solar architecture, potable
water via distillation and disinfection, hot
water, thermal energy for cooking.
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ACTIVE AND PASSIVE
SOLAR TECHNOLOGIES
Solar technologies are divided in passive
solar and active solar. Active solar
techniques include the use of photovoltaic
panels and solar thermal collectors to
convert sunlight into useful outputs. Passive
solar techniques include orienting a building
to the Sun or selecting materials with
favorable thermal mass or light dispersing
properties.
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ENERGY FROM THE SUN
The Earth receives 174 petawatts of incoming
solar radiation at the upper atmosphere.
Approximately 30% is reflected back to space
while the rest is absorbed by clouds, oceans and
land masses whose temperature rises.
By photosynthesis green plants convert solar
energy into chemical energy, which produces
food, wood and the biomass from which fossil
fuels are derived
From the table of resources it would appear that
solar, wind or biomass would be sufficient to
supply all of our energy needs.
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SOLAR THERMAL COLLECTOR
is a solar collector specifically
intended to collect heat
device for extracting
the energy of the sun
directly into a more
usable or storable
form.
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Typologies
•
•
•
•
•
Flat plat
Evacuated tube
Pool or unglazed
Asphalt Solar Collector
Volumetric thermal collectors
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Flat plat
• It’s the most common
type of solar thermal
collector
• It’s usually used as a
solar hot water panel
to generate solar hot
water.
• It’s generally used in
hotels and homes in
sunny climates such as
those found in southern
Europe.
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Evacuated tube
can perform well in colder conditions.
The high temperatures that can occur may
require special system design to avoid or mitigate
overheating conditions.
Has multiple evacuated glass tubes which heat up
solar absorbers.
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Pool or unglazed
• It is much like a flatplate collector.
• It is used extensively for
pool heating.
• It becomes ineffective
when the ambient
temperature gets
cooler.
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Asphalt Solar Collector
It collects heat using fluid
circulating through an
array of pipes embedded
n the surface of a road.
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Volumetric thermal collectors
• They are the oldest • They use principle of
volume absorption with
method of getting
modern designs that
heat from the sun.
include vacuum
insulation.
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Advantages
Very high temperatures reached
Good efficiency
A larger area can be covered by
using relatively inexpensive mirrors
Cheaper than photovoltaic modules
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Disadvantages
Concentrating systems require sun
tracking to maintain Sunlight focus at the
collector
Inability to provide power in diffused light
conditions
Power output drop drastically in cloudy
conditions as diffused light cannot be
concentrated passively.
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Photovoltaic cells
A solar cell, also called a photovoltaic
cell, is used to convert solar energy into
electrical energy
How do they work?
• Solar cells are made using semiconductors such as
silicon ;
• When particles of light are absorbed by the
semiconductor, they transfer their energy to some of
the semiconductor's electrons.
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Advantages
• Solar cells are also totally silent and nonpolluting ;
• Solar cells require very little maintenance,
greatly because there are no moving parts
that must be maintained;
• Solar cells can last a lifetime.
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Disavantages
• Solar energy systems do not work at night;
• Solar cells are currently costly and require a
large initial capital investment;
• For larger applications, many photovoltaic cells
are needed, corresponding to high investment
costs and large land requirements;
• The cost effectiveness of a solar energy system
is dependent upon the location and climate.
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Usage of solar cells
The semiconductor
most widely used in
solar cells is single-crystal
silicon.
Cells produced by this
method are prohibitively
expensive for all but the
smallest scale or most
specialised applications
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We have the best performance,
with these conditions:
– High noon
– Cloudless day
– In the equator
}
The insolation is about:1 Kw/m²
The Real PV performance
In Earth, the real PV performance is about:
12%
of the hypothetic
performance
Or with the best
commercially
available panels
Is about
20%
Also, to obtain the best PV performance,the solar panels, in
Northern Hemisphere are point due sud, whereas, in Southern
Hemisphere are point due north.
PHOTOVOLTAIC ENERGY
It is the field of technology
and research
related to the application of solar
cells for energy by converting sunlight
directly into electricity
SOLAR ENERGY
ELECTRICITY
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From the smallest
part of
photovoltaic energy
Solar panels
The solar cell
To a composition
of solar cells
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Liceo Scientifico “A. Oriani”
Ravenna
Interdisciplinary project
Subjects involved: English, Physics,
Information Technology
Teacher involved: prof.ssa
Siboni Elisabetta and
prof.ssa Laurena Petrizzi
Class II C PNI
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