The solar energy is radiated into space in all directions, this energy is distributed in a hypothetical spherical surface whose center is the sun and whose radius grows at the same speed as the establishment itself. The larger the radius of the sphere, the area becomes and the incident energy decreases if we want to know the theoretical value of solar energy incident on the vast land using the following equation: I = P / S Where: I = Irradiance (kW/m2 .) P = Power (W): 26W 4X10 to. S = surface of a sphere (m2): 4 X PI X R2. A = Mean distance earth sun (m): 1.5 x 10 to 11 m Solving terms I = 4 X 1026w / 4 x PI x (1.5×10 to 11 m) 2 = 1.4 kW/m2 The average value of the solar constant measured by satellites in outer space, just above our atmosphere is 1 cal/cm2 353 w / m 2 = 1940 min = 428 BTU / hr ft2 = 4871 MJ/m2 hr. Types of radiation from the earth's atmosphere significantly modifies the incident radiation because it acts as a filter, so the solar radiation reaching the earth's surface can be classified into three main types of radiation. Direct radiation: The form of the rays from the sun directly without undergoing any change. Diffuse radiation: That from the entire sky except the sun arrives. It is caused by dispersion effects mentioned above. Albedo radiation: Is that from the soil, due to reflection of part of the radiation incident on it.