Speaking of solar energy is commonly understood as the electric or thermal energy obtained by exploiting the rays of the sun that, every day, affect the Earth. The energy with which the sun radiates our planet is enormous , even if it is partly absorbed by the atmosphere and partly reflected by clouds. In addition to absorbing a certain percentage of radiation, the atmosphere modifies and alters its spectrum, but the solar radiations that reach the Earth determine the process of chlorophyll photosynthesis , and make the life of animals and plants possible.
Considering the energy potential that is poured on the earth’s surface every day, some methods have been studied to take advantage of it. Obviously, precisely because of the dispersion and the vastness of the earth’s surface, it is impossible to convert all the energy received from the sun in a useful way. However, the various technologies allow excellent results, both in terms of efficiency and in terms of the environment.
A system to exploit the energy of the sun is the installation of solar collectors (or panels) : these are devices that convert solar radiation into thermal energy, useful for heating or for the production of hot water. This type of system can be natural circulation (without electric pumps), taking advantage of the heat characteristic to rise upwards to favor the flow of the heat-carrying liquid in the exchanger, or forced circulation, with the presence of electric pumps speed up the process. Forced circulation, of course, increases the efficiency of the panel, and is necessary in the case of rigid external temperatures, or to produce hot water in the absence of sun and during the night.
The solar panels at a concentration acting through a series of reflecting mirrors, which concentrate the sun’s rays directing toward the heat transfer fluid, generating the steam used to produce electricity. Compared to solar collectors, concentration systems offer higher yields at reduced costs. This is a system that has recently been used for the operation of solar power plants: thanks to the presence of hundreds of mirrors, the heat generated moves the turbines and produces huge quantities of electricity .
The photovoltaic panels represent the solution for the production of electricity in residential and business environments, with the advantage of a strong reduction in costs with a minimum investment. The plant is made up of panels made of silicon cells which, if hit by the sun’s rays, are able to produce electricity. Placed so as to be constantly reached by sunlight, the photovoltaic panels provide the supply of electricity, varying according to position, irradiance, temperature and other parameters.
Solar energy is in any case a valid alternative way to provide the hot water and electricity needs and to heat the environment with excellent results and considerable savings. The photovoltaic system can be autonomous, allowing the storage of the energy produced and then deliver it at a later time, or connected to the electricity grid: in this case, the energy produced by the plant is “sold” to the grid operator , which in some cases proceeds to count it on credit.