Photovoltaic Systems

Photovoltaic systems are available in the form of small rooftop residential systems (less than 10 kW), medium-sized systems in the range of 10 to 100 kW, and larger systems above 100 kW connected to utility distribution feeders. The U.S. government launched a program to encourage the installation of 1,000,000 roof-top photovoltaic arrays over 10 years.

In addition to the solar array, there are several other aspects to a complete residential solar system. The figure below illustrates some of the additional equipment required. For a typical residential application, an array will be mounted in a fixed position to the roof of the house. The orientation and angle of inclination will directly affect the power output of the array. A tracking photovoltaic system uses a control system to maximize the array's exposure to the sun by changing the orientation and angle of inclinations as the sun moves daily and throughout the year.

The power produced by the array and batteries is direct current (DC), and the power required by household appliances is alternating current (AC). Power is changed from DC to AC through use of an inverter.

Geographic location will also affect the power output of a solar array. This type of information used with typical household energy consumption can help in selecting the size of array required. Batteries are often used in conjunction with solar arrays to store and release the power during times when the sun is not shining.