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PV panels are a solar-electric system's defining component, where sunlight is used to make direct current (DC) electricity. Behind a PV panel's shimmering facade, wafers of semiconductor material work their magic, using light (photons) to generate electricity-what's known as the photovoltaic effect. Other components in your system enable the electricity from your solar-electric panels to safely power your electric loads likelights, computers, and refrigerators.
PV panels are assigned a rating in watts based on the maximum power they can produce under ideal sun and temperature conditions. You can use the rated output to help determine how many panels you'll need to meet your electrical needs. Multiple modules combined together are called an array.
Although rigid panels are the most common form of solar electricity collector, PV technology also has been integrated into roofing shingles and tiles, and even peeland-stick laminates (for metal standing-seam roofs).
PV modules are very durable and long lasting-most carry 25-year warranties. They can withstand severe weather, including extreme heat, cold, and hail stones.
Basic Solar Panels
Monocrystalline Silicon Panels
Monocrystalline panels use crystalline silicon, a basic semiconductor material. Crystalline silicon is produced in large sheets that can be cut to a specific size and used as one large cell in a panel. Conducting metal strips are laid over the entire cell to collect electrons from the cell into an electrical current.
These panels are more expensive to produce than the polycrystalline panels that follow. However, they are highly efficient and are often more cost-effective in the long run as a result. Monocrystalline panels are typically 15-18% efficient, meaning that for every unit of solar energy that hits the cell, the panel can convert 15-18% of this energy into electricity.
Polycrystalline Silicon Panels
Polycrystalline, or multicrystalline, photovoltaics use a series of cells in place of the single large cell used in monocrystalline panels. Polycrystalline photovoltaics are the lease expensive form of photovoltaics available today, though the costs of producing individual cells can still be high. The drawback of these panels is that they have lower efficiency rates than monocrystalline panels, at 12-14% efficiency. There are several different types of polycrystalline panels:
Amorphous Silicon or Thin Film Panels
Thin-film panels are different from crystalline panels in their very makeup. Instead of molding, slicing, or drawing crystalline silicon to create a cell, amorphous silicon has no crystalline structure and can be applied as a thin semiconductor film on different materials. In addition to silicon, copper indium diselenide (CIS) and cadmium telluride (CdTe) can be used in amorphous or thin film panels. This film is then connected to metal conductor strips, but because the film is attached to another structural material it does not always require the same parts necessary for crystalline panels.
The primary advantage of thin-film panels lies in its low manufacturing costs and versatility. Because these panels are less time consuming and expensive to make, they can be produced much more efficiently. Because they can be applied in thin layers to different materials, it is also possible to make flexible, shaped, or unusually sized panels.
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