Solar TrackersSolar Trackers

Getting the most out of your Getting the most out of your PV panelsPV panels

Why Track?Why Track?

The most energy is The most energy is absorbed when a absorbed when a surface’s face is surface’s face is perpendicular to the sunperpendicular to the sun

Stationary mounted PV Stationary mounted PV panels are only panels are only perpendicular to the sun perpendicular to the sun once a dayonce a day

Improved performance Improved performance from each panel means from each panel means fewer panels are neededfewer panels are needed

Types of Trackers: PassiveTypes of Trackers: Passive

Made by Zomeworks and UniRacMade by Zomeworks and UniRac

Powered by a balancing material, usually Freon, Powered by a balancing material, usually Freon, shaded from and heated by sunshaded from and heated by sun

Panels turn as vapor shifts from side to sidePanels turn as vapor shifts from side to side

Advantages/DisadvantagesAdvantages/Disadvantages

No electrical partsNo electrical parts

ReliableReliable

SimpleSimple

Cost competitive to Cost competitive to stationary mountsstationary mounts

Morning wake up Morning wake up

Slow to reactSlow to react

Sluggish in cold Sluggish in cold weatherweather

More expensive to More expensive to shipship

Prone to wind gustsProne to wind gusts

Types of Trackers: ActiveTypes of Trackers: Active

Made by Array Made by Array Technologies (as Technologies (as Wattsun), SolarTrax, Wattsun), SolarTrax, and Small Power and Small Power SystemsSystems

Power by electricity Power by electricity (usually directly from (usually directly from panels)panels)– Optical Light SensorOptical Light Sensor– TimerTimer

Advantages/DisadvantagesAdvantages/Disadvantages

PrecisePrecise

Dual axisDual axis

Return to sunrise Return to sunrise position for earlier position for earlier startstart

Ignore temperatureIgnore temperature

Shipped in partsShipped in parts

Less reliableLess reliable

Sensitive to lightningSensitive to lightning

Higher initial costHigher initial cost

Uses electricity, but Uses electricity, but only about 5 watts per only about 5 watts per dayday

How Much More?How Much More?

Extra energy depends on location and siteExtra energy depends on location and site

Most beneficial with sunup to sundown solar Most beneficial with sunup to sundown solar windowwindow

PricesPrices

Wattsun complete 2 kW grid-tie system:Wattsun complete 2 kW grid-tie system:– $18,995 at $18,995 at

www.wattsun.com/internet_only_special.htmlwww.wattsun.com/internet_only_special.html

Zomeworks through Vermont SolarZomeworks through Vermont Solar– $612 - $2,312 for mounting pole only at $612 - $2,312 for mounting pole only at

www.backeastsolar.comwww.backeastsolar.com

Available at most internet stores that deal Available at most internet stores that deal in PV panelsin PV panels

Do sunflowers really follow the Do sunflowers really follow the sun?sun?

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