|2 / 3||  Solar energy|
|Renewable energy || Glossary of solar energy|
|Solar energy||faq: 1020|
The energy radiated from the Sun to Earth is called solar energy (renewable source), this is exploited directly as heat or electricity.
Solar radiation Earth orbit (without the filter of the atmosphere) at any instant corresponds to 1367 watts per m².
The amount of solar energy that reaches our planet is huge and distributed over the entire surface of the earth to transform it into electricity easily exploitable, large areas are needed.
technologies at our disposal are: the solar thermal panel, the panel concentrated solar power, and photovoltaic panels.
Panel Solar Heat
Used to heat water, uses the sun’s rays to heat a liquid contained in the plant, which in turn transfers heat to a tank of water with a heat exchanger. Thermal collectors are divided in turn into forced circulation (with the help of a pump is forced circulation of fluid, in this case the accumulation tank has fewer constraints on the position, but the plant is more complex and costly ) or natural (exploiting the motion of the conventional heated liquid, in this case the tank must be above the radiator.)
Panel to Focus
use parabolic panels to concentrate solar energy on a small area to heat a fluid (a common fertilizer for agriculture consists of a 60% sodium nitrate (NaNO3) and 40% potassium nitrate (KNO3)).
The heated fluid is stored in an insulated tank at a temperature of 550 ° C, the energy is then used to produce steam and as a normal thermal power plant, is converted into electrical energy generated.
The photovoltaic panels convert sunlight directly into electrical energy, the photoelectric effect has a conversion efficiency which depends on several factors, the most important is the material of the cells (15% for monocrystalline silicon modules, 13% for polycrystalline silicon modules, 8% in the amorphous silicon modules). The life cycle of a PV module is about 35-40 years.
The modules are classified according to the material used: monocrystalline silicon, polycrystalline silicon thin films (amorphous silicon, cadmium telluride (CdTe), cadmium sulfide (CdS), gallium arsenide (GaAs), indium Diselenide copper (CIS) and Diselenide copper indium gallium (CIGS)).