Simulation software can be used to maximize the efficiency your solar installations before you ever set foot on the roof.
Let’s take a roof orientation of east-southeast or 120°. Let’s say the roof is a typical 5/12 pitch or about 22 degrees. Since the orientation is 60 degrees out from due south we want to model the site to determine the best mounting configuration to maximize our solar exposure.
We ran a simulation on the site using a flat mount orientation to use as our baseline. This configuration returned a 71% solar fraction.
Rotating the collector on its side in a “landscape” orientation would orient the collector to 210°.
(120 + 90 = 210)
This angle goes beyond due south but we can infer that we would have an increased solar fraction verses the flat mount configuration since it is closer to 180°.
Resetting the simulation orientation to 210° and selecting 30° as the tilt angle resulted in a 76.2% solar fraction, or over a 5% increase. A tilt mount rack does not increase the installation cost much so this would be a practical upgrade.
The “book” says that to maximize solar gain during winter to add 15° to the site’s latitude.
(In our case 33° + 15° = 48°)
Running a simulation for every angle between 48 and 30 reveals that the optimal tilt angle for our given orientation of 210° is 35°. This configuration gives us a solar fraction of 76.6% per year. This results in nearly 6% increase in solar fraction per year which means more money saved.
Here at Metro Solar Atlanta we utilize Polysun’s premier simulation software before every solar hot water installation. Many others are available. Simulation software will save valuable time and maximize your installation’s efficiency. Maximizing efficiency is what solar is all about.
