PV/Solar Panels/Modules
PV Modules are the heart of the system. There are many brands. One of the unique features of photovoltaics is that arrays can be assembled at any scale, powering a home, a factory, or even a town through its local utility. Your installer will advise you as what is best for your location.
Information to be aware of when reviewing the details with your solar installer:
Warranty: PV modules are the longest lived component of a PV system. Top quality modules are designed to last at least 30 years and carry a 20 year warranty. Longevity rating is based on when the systems starts producing only 80% of the original power rating. For instance, some modules are warranted to produce at least 80 percent of their full-rated power after twenty-five years. The unit begins producing less and less power.
Certification (Module) : Make sure the solar module has a Underwriters Laboratories (UL) and Factory Mutual Research (FM) IEEE or IEC certification. Ask if the module passes the tests established by the US Jet Propulsion Laboratory (JPL Block V) to verify long-term reliability. Find out if the manufacturer regularly qualifies production units (rather than laboratory samples) to international standards.
System Size: 1kW produces between 135 and 150 kWh per month on average. A typical residential system is 1 to 2 kW. The size of your solar system depends on your current electricity usage. The number of panels needed can also vary depending on which panel type is used. In planning to install a photovoltaic system, the correct amount of photovoltaics needs to be determined on a case by case basis. (Chart showing panels needed to power everyday items requiring electricity.)
Space: A single PV Modules needs from 150 to 115 square feet of space. Thin-film types need more space. Your available roof or installation space with the proper orientation and inclination will determine what percentage of this power could be produced with a solar PV system. Each square foot of installation space averages to about 10 Watts of power generation. 1,000 Watts equals 1 kilo-watt (kW). You may need racks mounted to the roof to incline the panels at the ideal angle. You can also use ground based mounting racks if you have enough sunny space and the right orientation.
Shading: No shading year-round between the hours of 9am and 4pm from trees, other buildings and common obstructions such as vents, chimneys, dormers, etc.; and a relatively south-facing roof orientation. If your roof cannot provide this, there are ground-mounted systems which provide more flexibility in locating the modules. (See our blog on a recent issue of neighbor's shade trees.)
The types of PV modules used today are; single crystal, “multi” or “poly” crystalline, and amorphous silicon. www.norcalsolar.org/Photovoltaics-Basics/PV-Technology.html
- Single-crystal modules are currently the most efficient type available, meaning that they produce the most power per square foot of module. The cells are fragile so they must be mounted in a rigid frame, and the modules usually have a polka dot or checkered pattern.
- Multicrystalline modules are made of cells cut from multiple crystals that are grown together in an ingot. They are similar to single crystal cells in module structure but slightly less efficient since they require a bit more surface area to produce the same amount of electricity.
- Amorphous silicon modules (e.g. thin film) are made from cells created by depositing a micro-thin layer of silicon directly onto a sheet of glass, plastic, or other substrate. Although they are less efficient and require up to 50 percent more space, they can be mounted on a flexible backing, making them easier to transport and ideal for building-integrated uses, such as roofing tiles or shingles. Thin film is competing with today's dominant solar technology: silicon solar panels and is considered the breakout technology effectively competing with current energy sources.
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Types of Crystalline panels
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Types of Thin Film panels
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