The document discusses the solar constant, which is the rate at which solar energy arrives at the top of the Earth's atmosphere. It states that the Sun releases approximately 384.6 yotta watts of energy as light and radiation, which appears from Earth as radiation from a black surface at 5,762 degrees Kelvin. The solar constant can be approximated using an equation that takes into account how the distance between the Earth and Sun varies throughout the year. It also mentions spectral distribution of solar intensity and different types of solar radiation including direct, diffuse, and total radiation.

1. Solar Constant
Dr. Challa Babu
ASCET, Gudur

2. Cont’d
 The Sun releases an estimated 384.6 yotta watts (3.846×1026 watts) of energy in the form
of light and other forms of radiation.
As viewed from earth, the radiation coming from the sun appears to be equivalent to that
black surface at 5762° K .
The rate at which solar energy arrives at the top of the atmosphere is called the SOLAR
CONSTANT,

3.  The distance between the sun and earth varies through out the year.
This can be approximated by the equation
Where n = day of the year
 Spectral distribution of solar intensity → to know the percentage of radiation obtained at
certain wave length
𝐼
𝐼𝑠𝑐
= 1 + 0.033cos
360(𝑛 − 2
365

5. DIRECT, DIFFUSE AND TOTAL RADIATION

6. Types of Solar Insolation

8. Zenith and Azimuth angle

9. Thank you