THE BASICS OF SOLAR POWER
Producing common electricity with solar
Solar power to produce electricity is not the same as using solar to
produce heat. Solar thermal principles are applied to produce hot fluids or air. Photovoltaic
principles are used to produce electricity. A solar panel (PV panel) is made of the natural
element, silicon, which becomes charged electrically when subjected to sunlight.
This electrical charge is consolidated in the PV panel and directed
to the output terminals to produce low voltage Direct Current - usually 6 to 24 volts. The most
common output is intended for nominal 12 volts, with an effective output usually up to 17 volts. A
12-volt nominal output is the reference voltage, but the operating voltage can be 17 volts or
higher much like your car alternator charges your 12-volt battery at well over 12 volts. So there's
a difference between the reference voltage and the actual operating voltage.
Solar panels are directed at solar south in the northern hemisphere
and solar north in the southern hemisphere (these are slightly different than magnetic compass
north-south directions) at an angle dictated by the geographic location and latitude of where they
are to be installed. Typically, the angle of the solar array is set within a range of between
site-latitude-plus 15 degrees and site-latitude-minus 15 degrees, depending on whether a slight
winter or summer bias is desirable in the solar power system. Many solar arrays are placed at an
angle equal to the site latitude with no bias for seasonal periods.
The intensity of the Sun's radiation changes with the hour of the
day, time of the year and weather conditions. To be able to make calculations in planning a solar
power system, the total amount of solar radiation energy is expressed in hours of full sunlight per
m², or Peak Sun Hours. This term, Peak Sun Hours, represents the average amount of sun available
per day throughout the year.