A vast amount of clean sun energy is coming to Earth every second. Should we use only 0.01% and solve all energy needs?
Solar constant
A solar constant is a measurement of the solar electromagnetic radiation available in a meter squared at Earth’s distance from the sun. Satellite measurements can provide this information. Stefan-Boltzmann constant. In January, when the sun is closest to the earth, the solar heat on the outer edge of the earth’s atmosphere is about $1400 \text{ W/m}^2$. When the sun is at its furthest distance from us, on July 4, it is about $1330 \text{ W/m}^2$. We will assume for our calculations that it is 1377 W/m2.
Extraterrestrial Radiation $I_o$
The distance between the Earth and the Sun changes during the year. We refer to the solar radiation at the top of the atmosphere as "extraterrestrial radiation." Due to the change in the distance between the Earth and the Sun, the extraterrestrial radiation is changing.
Flux of solar radiation $I_B$
The flux of solar radiation, which in the form of direct radiation reaches the earth’s surface, is less than $I_o$ due to absorption and dispersion in the atmosphere. The Beer-Lambert law provides the estimation of irradiation on the earth's surface. This measurement can be represented as the energy of solar radiation that falls normally per square meter per unit time on the surface of the Earth.
3 types of radiation
Solar energy is transmitted through three types of radiation:
- Direct $I_B$
- Diffuse $I_D$
- Reflected $I_R$
Solar Mass AM = 1.5
3 types of radiation
Direct component $I_{BC}$
To calculate the direct radiation component, it is necessary to calculate the incident angle under which direct solar rays fall on the observed module. This angle is a function of the altitude, azimuth angle, and tilt of the module.
Diffuse component $I_{DC}$
Clouds or dust particles scatter some of the sun's rays as they travel through the atmosphere. Given the stochasticity of that process, this radiation component cannot radiate evenly from all directions. Placing the module in a horizontal plane would allow this component to reach its maximum value on a cloudy day.
Reflected component $I_{RC}$
The earth partially reflects solar rays, and the intensity of this reflection depends on the surrounding surface. The qualitative measure of reflection ranges from 0.1 for asphalt to 0.8 for snow.
The total radiation reaching the module consists of three components: direct, diffuse and reflected.
Algorithm and functions
The SPAC (solar panel angle calculator) application uses the following dependency functions for calculation.
SPAC algo