Photovoltaics
The Photovoltaic (voltage from light) effect or the process of utilizing sunlight
to make electricity has been observed since the 1800's. Sunlight shining directly
on certain materials causes the electrons in the molecules of those materials to
become excited. Given a path to follow, these electrons will flow in one direction,
creating electricity.
PV provides utility back-up power; keep your lights on when the power goes out as
well as other loads like wells, TV, fridge, computer, garage door opener, alarm etc..
The use of a grid tie allows you the ability to sell extra power back to the utility
grid - Reduce your utility bill by spinning your meter backwards. Good applications
for PV systems include utility back-up power, remote housing such as mountain top were
power lines may not be run and small lighting needs such as sign and entrance lights
that require additional lines.
The picture to your right shows one 115watt photovoltaic panel. Panels come in sizes
ranging from 5watts up. When you take a cluster of panels and make an array you are
capable of powering your entire house. A PV system installed by CommonWealth Solar
provides years of reliable energy production.
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An array of photovoltaic panels is assembled to collect the sun's energy. The number
of panels that are used can determine the amount of power supplied. The array to
the left produces 2kw, and is backed up with a propane generator.
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To the right is a 5kw system that is mounted on trackers that allow the PV panels to
follow the sun. These are motorized stands that turn to face the PV panel directly
at the sun from dawn till dusk, this maximizes their performance.
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As the PV panels make electricity they charge a battery bank such as the one to the left.
This stores the power untill it is needed such as in cloudy weather or at night.
These battery banks can be charged by different means such as PV, generator, or even the
utility grid. An intelligent battery charger is used to properly charge the battery bank.
Advanced charging algorithms provide fast recharging while increasing battery life up to 10 years.
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PV panels produce DC power; in order to convert this to 240 volt (AC) power an inverter is used.
The inverter is the brains of the system; it tells the system where to get power and converts
it to a usable form. Each inverter produces 120 volt power so two units are used and stacked
in order to run larger appliances. At the top of the inverters is a transfer switch used to
manually switch from PV to the grid.
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