## BTU Earth

The greater the radius of the sphere area increases and the incident energy decreases if would like to know the value theorist of the incident solar energy on Earth vasta used the following equation: I = P / S where: I = irradiance (Kw/m2). P = power (W): 4 X 10 to the 26W. S = surface of a sphere (m2): 4 X PI X R2. R = average Earth Sun distance (m): irradiance and is measured in units of w/m2. The integration of the irradiance in a given period of time is known as sunstroke and its units are Kwh/m2, KJ/m2, BTU/ft2. Heat stroke can also be expressed in terms of solar hours peak. The peak solar time equals the energy received during one hour at an average irradiance of 1000 w/m2.

Relative movements Sun-Earth solar power plants need sunlight to function, therefore, it is important to know the way in which this interacts with the earth so that we can describe their behavior and trajectory in the celestial vault and succeed with this knowing accurately the performance of the installation that we are proposing a yearas the seasons change and along with them the climatic conditions of the place, also the route of the Sun by celestial as well as, the energy we receive from the. Translational movement: this movement is that makes the earth revolving around the Sun. It does not describe one elliptical orbit, which is called the ecliptic. The length of the tour is approximately 365 days 5 hours 48 minutes, at a speed of 108,000 km./h. Rotational movement: this movement does the earth around its axis, i.e. on the straight line joining the North and South poles, this axis maintains a roughly constant direction and forming an angle of 2345 degrees to the ecliptic plane called the obliquity of the ecliptic. Due to this obliquity angle formed by the equatorial plane of the Earth with the straight line joining the centers of the Earth and the Sun, the Earth is changing permanently more 2345 grades and less 2345 degrees.