Civil Engineering Reference
In-Depth Information
electricity will be produced by renewable energy sources, with up to 12%
of this being specifi cally related to PVs.
12.3
Functions of a photovoltaic (PV) cell
Although technology has branched out in relation to the combination of
materials used and the production methods selected, the basic operating
principles are the same as they all aim to take the range of intensities from
daylight and absorb the photons from it to create an electric current, hence
the reason it was named 'photovoltaic' as it produces electricity from light
(Fig.12.2).
The structure of the cell as shown in Fig.12.3 outlines simply how in the
basic fi rst generation crystalline silicon solar cell the sunlight is transferred
into electrical energy, which is really the only energy source with no limit
to its potential. These cells are manufactured from similar materials to those
used in semiconductor wafers which create an electric fi eld with one side
being negative and the reverse positive. However, a PV panel is not a single
cell, but rather a combination of series and parallel cells, which creates an
array and are connected and housed in a structure encapsulated by a glass
surface. With the cells connected in series providing a larger voltage and
Photo
+
Volt
=
Photovoltaic
After Count Alessando Volta
who named the unit of
electromotive force
Greek word for
light
Electricity produced by light
12.2
The origin of the word photovoltaic.
Sunlight
Front
contact
Semi-conductor
(treated material)
Back
contact
Anti-reflective
coating
12.3
Operation of a basic fi rst generation PV.
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