Introduction to Photovoltaic Solar Panels

The technology behind photovoltaic (PV) solar panels enables use of clean, efficient, renewable solar energy. It presents a compelling alternative to standard utility power for Arizona consumers looking to go green and save money. Unlike fossil-fuel energy sources, solar does not pollute the atmosphere with carbon emissions and is at top generating capacity during peak use times, the middle of the day.

PV Panels come in a variety of efficiencies, sizes, colors, and materials, consisting of many round or square cells. Connected in a series, these cells generate DC voltage.  Typically, a panel makes 12 volts at approximately four amps.  Rating solar panels occurs in watts, determined with the following formula:

Voltage = Potential
Amperage = Flow
Watts = Volts x Amps

Standard Test Conditions (STCs), used to rate solar panels, are standard environmental conditions. STCs entail a perfect day (25 degrees Celsius), with full, clear sunshine at 1,000 watts per square meter.

Silicon is the main ingredient in photovoltaic cells, and is the second most abundant element on Earth. Unfortunately, it is normally found in the form of silica (also known as sand). The chemical symbol of silicon is SiO₂.  A variety of methods exist to extract the pure silicon; the most common is carbothermic reduction. This extraction method heats the silica to 1700 degrees Celsius in the presence of carbon.  As the silicon cools it forms into crystals; the longer the silicon to cools, the larger the crystals that develop. The crystal-extraction level of difficulty is a major factor in determining its cost because of cooling methods.

Monocrystalline and Polycrystalline cells are the most popular choice for efficient, silicon-based PV panels.  Thin film solar technology is an alternative to both that is finding its way into the solar market as well because it is less expensive; however, its efficiency rating is lower as well.

Polycrystalline cells contain many crystals and have more surface imperfections than monocrystalline. They absorb less solar energy and produce less electricity.  However, the process of creating a polycrystalline cell is easier and less expensive, making it a viable alternative.

Monocrystalline-based solar panels are usually smaller, with a perfectly uniformed, less “grainy” appearance than polycrystalline-based counterparts. The costs of monocrystalline- and polycrystalline-panels per watt of power output are similar, as polycrystalline panels are larger, requiring more materials and cells.

Solar panels are most efficient in power production when facing true south, perpendicular the path of the sun.  This enables maximum power production and zero degradation.  Shading can reduce maximum power production as well, as cells do not receive enough light to produce efficiently. Landscaping itmes and structures are common impediments. Proper system engineering takes this into account.

Tags: Solar Panels AZ, Photovoltaic Solar in Arizona, solar technology, photovoltaic solar

References:

https://solarjuice.com/blog/pv-panels/monocrystalline-vs-polycrystalline/

http://solarconsumerreporting.webs.com/solarpvfacts.htm

http://gigaom.com/cleantech/faq-thin-film-solar/