1. Getting the most out of your PV panels
Solar Trackers
Getting the most out of your PV panels

2. Why Track?
The most energy is absorbed when a surface’s face is perpendicular to the sun
Stationary mounted PV panels are only perpendicular to the sun once a day
Improved performance from each panel means fewer panels are needed

3. Types of Trackers: Passive
Made by Zomeworks and UniRac
Powered by a balancing material, usually Freon, shaded from and heated by sun
Panels turn as vapor shifts from side to side

4. Advantages/Disadvantages
No electrical parts
Reliable
Simple
Cost competitive to stationary mounts
Morning wake up
Slow to react
Sluggish in cold weather
More expensive to ship
Prone to wind gusts

5. Types of Trackers: Active
Made by Array Technologies (as Wattsun), SolarTrax, and Small Power Systems
Power by electricity (usually directly from panels)
Optical Light Sensor
Timer

6. Advantages/Disadvantages
Precise
Dual axis
Return to sunrise position for earlier start
Ignore temperature
Shipped in parts
Less reliable
Sensitive to lightning
Higher initial cost
Uses electricity, but only about 5 watts per day

7. How Much More? Extra energy depends on location and site
Most beneficial with sunup to sundown solar window

8. Prices Wattsun complete 2 kW grid-tie system:
$18,995 at
Zomeworks through Vermont Solar
$612 - $2,312 for mounting pole only at
Available at most internet stores that deal in PV panels

9. Do sunflowers really follow the sun?
When the plant is in the bud stage, it tends to track the movement of the sun across the horizon. Once the flower opens into the radiance of yellow petals, it faces east. No one knows why. However, it is likely a defensive response. Facing south or west could result in sun-scalding of seeds during very hot days.