physicist Edmond Becquerel first described
the photovoltaic effect in 1839, but it remained
an unexplored avenue for the next three quarters
of a century. At only 19, Becquerel found
that certain materials would produce small
amounts of electric current when exposed to
light. Heinrich Hertz studied the effect in
solids in the 1870s, producing PV cells that
converted light to electricity at 1% to 2%
efficiency. Selenium cells were used as light-measuring
devices in photography.
The big step at commercializing PV was the
development in the 1940s of the Czochralski
process, generating highly pure crystalline
silicon. In 1954 the Bell Laboratories used
the Czochralski process to produce a 4% efficient
crystalline silicon cell.
cells, modules, panels and arrays
Photovoltaic (photo - light and voltaic -
voltage producing) or PV technology converts
sunlight directly into electricity. The basic
building block of Solar Module is the PV cells.
A solar or PV cell consists of semiconducting
material that absorbs the sunlight. The solar
energy knocks electrons loose from their atoms,
allowing the electrons to flow through the
material to produce dc electricity.
Photovoltaic cells are connected electrically
in series and/or parallel circuits to produce
higher voltages, currents and power levels.
Photovoltaic modules consist of PV cell circuits
sealed in an environmentally protective laminate,
and are the fundamental building block of
PV systems. Photovoltaic panels include one
or more PV modules assembled as a pre-wired,
field-installable unit. A photovoltaic array
is the complete power-generating unit, consisting
of any number of PV modules and panels. They
are environment-friendly, noiseless, pollutant-free
and produce no harmful residues.
of a Solar Power System
Solar Systems begin with the solar module.
Modules gather solar energy in the form of
sunlight and convent it into direct current
(DC) electricity. The more sunlight they receive,
the more electricity they produce. Solar modules
are the heart of the system. They are the
Components such as charge regulators, batteries
and inverters regulate, store, condition and
deliver the electricity. Other elements connect
the different components of the system.
PV modules, because of their electrical properties,
produce direct rather than alternating current
(AC). Direct current (DC) is electric current
that flows in a single direction - the type
of current you get from a torch battery. Alternating
current is electric current that reverses
its direction at regular intervals, for example
as supplied by utility companies through the
national grid system. In the simplest PV systems,
DC current is used directly. In applications
where AC current is necessary, an inverter
can be added to the system to convert the
dc current to ac current.
Typical PV System Components
of Solar Power Systems
size and type of the PV system that will meet
your expectations depends on your individual
needs, site location and climate.
Without Battery Backup:
Since there is no battery to store electrical
energy, energy is used immediately. Common
applications are direct power to DC loads,
water pumping and telecommunications. With
an inverter it can also power AC loads. This
system only works when it's sunny.
With Battery Backup:
A Stand-Alone System with Battery Backup can
supply power 100% of the time including at
night, on cloudy days and when the utility
power is down. Excellent for remote applications
where utility grid is inaccessible; cabins,
boats, RVs and for emergency backup systems.
This is the simplest and most cost effective
way to connect PV modules to regular utility
power. Grid-Connected systems can supply solar
power to your home and use utility power as
a backup. Grid- Connected Solar Power Systems
work in parallel to the grid, providing the
best possible combination of reliability,
pricing and sustainability benefits. A properly
designed and installed grid connected Solar
Power System works seamlessly with exsisting
building systems, resulting in zero impact
to building operation, maintenance and performance.
The grid inverter automatically synehronises
with the grid network; no additional controls
in all countries, to install a grid connected
system, the consumer needs to get the permission
from the local Utility Company or Electricity