Let us take an example of city of Aurangabad in Maharashtra, India where the solar modules should be mounted at 200 to the horizontal ground level.
LESS GENERATION
- Installation of Panel:
Flat (parallel to ground & not related to latitude of place)
- Less capture of solar energy because the incidence of solar rays are at 1100 w.r.t. average position of sun in a year
OPTIMUM GENERATIONitude
- Installation of Panel:
200 to ground (At latitude angle of Aurangabad)
- Optimum capture of solar energy because the incidence of solar rays are at 900 w.r.t. average position of sun in a year
The solar radiation is amount of energy contained in sunlight falling on earth. It is measured in W/m2. Global solar radiation constant is 1300W/m2 and it is calculated by dividing the solar energy falling on earth by surface area of earth. The amount of solar radiation a location receives depends on a variety of factors:
- Geographic location - Time of day
- Season - Local landscape
- Local weather
Air Mass Index
The Air Mass quantifies the reduction in the power of sun light as it passes through the atmosphere and is absorbed by air and dust. Technically, it is the path length which sun light takes through the atmosphere normalized to the shortest possible path length (that is, when the sun is directly overhead). Earth has Air Mass Index of 1.5 and hence the global solar radiation constant become 1000W/m2.
The Air Mass is defined as:
AM=1/cos θ
where θ is the angle from the vertical (zenith angle). When the sun is directly overhead, the Air Mass is 1. The air mass represents the proportion of atmosphere that the light must pass through before striking the Earth relative to its overhead path length, and is equal to Y/X.
