ABSTRACT
Solar energy is the electromagnetic energy transmitted from the sun (solar radiation). The amount that reaches the earth is equal to one billionth of total solar energy generated, or the equivalent of about 420 trillion kWh. Energy is emitted by the sun as electromagnetic waves, 99% of which have a wavelength between 0.2 and 4.0 micrometers. Solar energy reaching the top of the earth’s atmosphere consists of about 8% ultraviolet radiation, and 46% infrared radiation. Diffuse radiation is that solar radiation received from the sun after its direction has been changed by reflection and scattering by the atmosphere. Because of the solar radiation is scatted in all directions in the atmosphere, diffuse radiation comes to the earth from all parts of the sky. Solar thermal equipment captures and transfers the thermal energy available in sunlight, which can be used to meet heat requirements in different temperature ranges.
