Mathematical Formula: Shadow Length Calculation
If the shadow creating object is in East-West direction of proposed Solar PV array location, below formula should be used:
Shadow Length (m) = H (m) x [Sin (Azimuth) / Tan (Altitude) ]
Please note that, if the shadow creating object is on East side of proposed solar PV array location, consider morning time Azimuth and Altitude angles. If the shadow creating object is on West side of the proposed solar PV array location, consider evening time Azimuth and Altitude angles.
If the shadow creating object is in North-South direction of proposed Solar PV array location, below formula should be used:
Shadow Length (m) = H (m) x [Cos (Azimuth) / Tan (Altitude) ]
Please note that if the shadow creating object is in North-South direction of proposed solar PV array location, consider both morning and evening time Azimuth and Altitude angles.
Note: Azimuth and Altitude angles for a particular location and time can be taken from freely available websites such as: www.sunposition.info or https://power.larc.nasa.gov
To understand this better let’s have a look at few examples on next pages
Thank you for providing assistance for those of us who are studying through you, sir.
I read your lecture on how to conduct shadow analysis on roof tops regarding PV array installation.
My question is what instrument or how can the height of the object or building casting shadow can be determined if you don’t have the data sheets of the proposed area, especially when it will amount to encroachment measuring somebody’s building or structure?