Determining Module Tilt Angle

Solar modules work best when they are perpendicular to the sun's rays. Because tracking is not always possible, modules mounted in the Northern hemisphere are generally mounted facing South and modules mounted in the Southern hemisphere facing North.

The physical factors which affect the output of the panel is the amount of sunlight it receives and the temperature of the cells. An increase in temperature causes the current to increase slightly, but causes the voltage to decrease significantly. This results in a decrease of power from the solar module. For this reason it is desirable to keep the solar panel at the lowest temperature possible. This can be achieved be making sure that there is good ventilation between the panel and the mounting structure.

Modules should be mounted with the orientation and tilt angle required for consistent performance. The location selected must have direct access to sunlight from 09h00 to 15h00 on the shortest day of the year. Calculate the correct tilt angle by using the latitude of the site plus 15 degrees, with sites in the Southern hemisphere facing north and sites in the Northern hemisphere facing south. This will allow for a consistent energy output throughout the year.
A tilt angle of 5 to 15 degrees will result in the maximum energy output in the summer but less in the winter.