Photovoltaic Panels, Harnessing The Sun's Power...

Photovoltaic panels are devices that convert the light from the sun into electrical energy. Irradiance is the measure of the sun's power at the surface of the earth and averages 1000 watts per square meter of ground. Insolation is the amount of energy available at a specific location and is measured in "full sun hours". The amount of electrical energy produced by the cell compared to the amount that is available is called the solar cell efficiency. The typical cell captures 14-16% of the available energy or 140-160 watts of power for each square meter of panel area.

When light strikes a solar cell, some of the photons knock electrons free from their orbit around the atoms of the material. These free electrons (electricity) are then directed to devices to perform work for us. The typical cell produces about .5 vdc while the current output is directly proportional to the surface area of the cell.

Individual solar cells are normally electrically connected to each other to form panels called photovoltaic modules. There are basically three types of modules available to the homeowner. The most common are the typical roof mounted modules or ground mounted modules. For situations where you do not want to see the panels, you can get building integrated photovoltaic panels (BIPV). These modules are designed to take the place of traditional roofing materials and blend into the roof.

These assemblies are then combined to form photovoltaic arrays which combine all of the system's electrical energy to provide useful power for your home.

This DC power can be used to charge batteries or it can be converted to alternating current (AC power) through a device called an inverter. This AC power is then used to supply the electricity to the appliances in the home.

Systems that use batteries are commonly called off-grid systems because they can store energy in the batteries for the times when the sun is not shining. Other systems use batteries as a backup in case the utility company cannot provide power. The most common type of system does not use batteries and is called a grid tie system. **NOTE** A grid tied system, without battery backup, must shut down when power from the utility company goes out. If you live in an area where power outages are common, you would want a system with battery backup.

Most of the system manufacturer's provide design services and they offer systems as complete packages with different electrical outputs. A simple site survey is performed to ensure that you have a suitable location (which most people do) and a package is selected based on your home's needs and location. We have teamed up with GoGreenSolar to assist you in purchasing and implementing a solar solution for your home. With the widget below, you can check out your options.

There are many brands and system options available but to cut through all of the sales hype you can use our residential solar system ratings. You can see how the systems stack up through a side by side comparison of the photovoltaic panels and other system componets.
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