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CHAPTER ONE
INTRODUCTION
General background:
Solar energy is clean and available in abundance. Solar technologies use the
sun
for provision of heat, light and electricity. These are for industrial and
domestic applications. With the alarming rate of depletion of depletion of major
conventional energy sources like petroleum, coal and natural gas, coupled with
environmental caused by the process of harnessing these energy sources, it has
become an urgent necessity to invest in renewable energy sources that can power
the future sufficiently. The energy potential of the sun is immense. Despite the
unlimited
resource however, harvesting it presents a challenge because of the
limited efficiency of the array cells. The best efficiency of the majority of
commercially available solar cells ranges between 10 and 20% [1], [2]. This
shows that there is stillroom for improvement. This project seeks to identify a
way of improving efficiency of solar panels. Solar tracking is used. The tracking
mechanism moves and positions the solar array such
that it is positioned for
maximum power output. Other ways include identifying sources of losses and
finding ways to mitigate them.
When it comes to the development of any nation, energy is the main driving
factor. There is an enormous quantity of energy that is extracted, distributed,
converted and consumed every single day in the global society.
Fossil fuels
account for around 85 percent of energy that is produced. Fossil fuel resources
are limited and using them is known to cause global warming because of
emission of greenhouse gases. There is a growing need for energy from such
sources
as solar, wind, ocean tidal waves and geothermal for the provision of
sustainable and power. Solar panels directly convert radiation from the sun into
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electrical energy. The panels are mainly manufactured from semiconductor
materials, notably silicon. Their efficiency is 24.5% on the higher side. Three
ways of increasing the efficiency of the solar panels are through increase
of cell
efficiency, maximizing the power output and the use of a tracking system.
Maximum power point tracking (MPPT) is the process of maximizing the
power output from the solar panel by keeping its operation on the knee point of
P-V characteristics. MPPT technology will only offer maximum power, which
can be, received from stationary arrays of solar panels at any given time. The
technology cannot however increase generation of power when the sun is not
aligned with the system.
Solar tracking is a system that is mechanized to track the position of the sun
to increase power output by between 30% and 60%
than systems that are
stationary. It is a more cost effective solution than the purchase of solar panels.
There are various types of trackers that can be used for increase in the amount
of energy that can be obtained by solar panels. Dual axis trackers are among the
most efficient, though this comes with increased complexity. Dual trackers track
sunlight from box axes. They are the best option for places where the position of
the sun keeps changing during the year at different seasons. Single axis trackers
are a better option for places around the equator where there is no significant
change in the apparent position of the sun.
The level to which the efficiency is improved will depend on the efficiency
of the tracking system and the weather. Very efficient trackers will offer more
efficiency because they are able to track the sun with more precision. There will
be bigger increase in efficiency in cases where the
weather is sunny and thus
favorable for the tracking system.