2) Will it work Here?

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Is the slope or angle of the roof important?

Ideally the PV array should always be mounted so as to take full advantage of the sunlight. The angle that the modules are installed at is often based on the slope of the existing roof. Racking can be purchased that changes the angle of the module; however, the racking can be more expensive and when the modules are no longer parallel to the roof additional considerations come into play. Usually keeping the modules parallel to the roof is the simplest and most cost effective option; although, at times changing the slope is worth the small gains in production.


What is the best angle?Bar chart, Tilt Angle Comparison of modules, production relative to latitude tilt of 53 degrees

The NAIT Solar Photovoltaic Reference Array was set up to test some commonly utilized fixed angles (14°, 18°, 27°, 45°, 53°, and 90°) and to determine if there was an optimal angel. As it turns out the best fixed angle was 53°; however, the difference in production levels between modules angled at 53° and 14° was approximately 11%.

If you had an architect design a building for solar PV a few years ago, before the price of modules dropped, they might design the roof with a focus on the angle, today they are more likely to focus on the number of modules you can have installed.


Reports: Optimal Recorded Module Angle Per Month

  • Man working on Solar Photovoltaic array, several modules placed at different anglesJanuary = 90°
  • February = 53°
  • March = 53°
  • April = 45°
  • May = 18°
  • June = 18°
  • July = 18°
  • August = 27°
  • September = 53°
  • October = 53°
  • November = 90°
  • December = 90°

Tracking Systems

When looking at ground mounted systems you can pick the angle that works best for the location. Solar tracking systems are also an option. A solar tracker is a device that keeps the PV array pointed towards the sun throughout the day. In most cases, the mounting is fixed at one angle (a right angle to the sun at noon), but special systems can be installed that allow adjustments to be made according to the season.

Follow the link “Solar Trackers” for more information from Wikipedia.


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