The position of your PV modules is very important to catch the sun's rays and generate electricity; obviously, they must face the sun. But the sun rises in the east and moves westward during the day, which makes maintaining a direct line of sight quite difficult.
A fixed mount should face south. Panels on a tracking unit will follow the sun's course during the day. The best location for both mounts is wherever they are unshaded by buildings, trees or obstructions of any kind – a decision further complicated by changes in the sun's path throughout the year. You can make it easier to assess your site by getting a Solar Pathfinder to determine the best installation spot. This device tracks the sun by capturing light through a focusing dome The focused light burns a track along special paper (just like using a magnifying glass) to indicate sunlight availability - gaps in the track indicate unacceptable obstructions to the PV panels.
Deciding Whether To Rack Or Track Roof Mounts
Mounting the panels on a south-facing roof is the simplest installation, but remember that solar south is not the same as magnetic south due to magnetic declination (except in certain locations). Fixed-mount arrays cannot change their angle for a change in season. There is hardly any sunlight during the winter while the sun is almost directly overhead in summer: for roof-mounted or fixed systems, set the PV array at an angle that equals your latitude. Racks can be adjusted according to the season, with a 15-degree reduction during summer and a similar vertical adjustment during winter, to keep the maximum surface area directly facing the sun.
Ground Mounts
It may be difficult to clear snow and ice with roof-mounted PV arrays: a ground- or pole-mount may be easier and more affordable. Use aluminum or galvanized steel to reduce corrosion. Your mount system should have a hinge assembly to adjust the tilt angle during the different seasons. A simple ground mount can be made from a piece of preserved cedar wood, which may not outlast the panels.
Caution: PV modules which are ground mounted are open to theft as they are costly components. Apply security bolts, sink the legs into concrete footings to ensure permanency or get a good guard dog. If you use a snow blower, ground-mounted systems are not a good idea. You'll also have to watch out for lawnmowers and energetic children who may send rocks and debris flying into your modules.
Tracking Mounts
Tracking mounts follow the course of the sun, facing east at night, tilting progressively westward through the day and returning to the east after sunset. Trackers can be electronically controlled with a manual or automatic adjustment device to compensate for seasonal differences.
Passive-controlled trackers can be found at The Track Rack by Zomeworks. Check out www.zomeworks.com. The simple mechanism uses the sun's heat to work the tracker, unlike active trackers. Track Rack models face west when idle and may waste the first couple of sunlight hours on cold days, before "waking up" and tracking.
The following considerations may impact