Photovoltaic (fo-to-vol-ta-ik) systems are solar systems that Photovoltaic (fo-to-vol-ta-ik) systems are solar systems that

produce electricity directly from sunlight. The term "photo" comes produce electricity directly from sunlight. The term "photo" comes

from the Greek "phos," meaning light. "Voltaic" is named for from the Greek "phos," meaning light. "Voltaic" is named for

Alessandro Volta (1745-1827), a pioneer in the study of electricity Alessandro Volta (1745-1827), a pioneer in the study of electricity

for whom the term "volt" was named. Photovoltaics, then, means for whom the term "volt" was named. Photovoltaics, then, means

"light electricity." Photovoltaic systems produce clean, reliable "light electricity." Photovoltaic systems produce clean, reliable

electricity without consuming any fossil fuels. They are being used electricity without consuming any fossil fuels. They are being used

in a wide variety of applications, from providing power for watches, in a wide variety of applications, from providing power for watches,

highway signs, and space stations, to providing for a household's highway signs, and space stations, to providing for a household's

electrical needs.electrical needs.

• Photovoltaic Cell Photovoltaic Cell -- Thin squares, discs, or films of semiconductor material -- Thin squares, discs, or films of semiconductor material that generate voltage and current when exposed to sunlight.that generate voltage and current when exposed to sunlight.

• Module Module ---- Photovoltaic cells wired together and laminated between a clear Photovoltaic cells wired together and laminated between a clear superstrate (glazing) and encapsulating substrate. superstrate (glazing) and encapsulating substrate.

• Array Array -- One or more modules with mounting hardware and wired together -- One or more modules with mounting hardware and wired together at a specific voltage.at a specific voltage.

• Charge Controller Charge Controller -- Power conditioning equipment to regulate battery -- Power conditioning equipment to regulate battery voltage. voltage.

• Battery Storage Battery Storage -- A medium that stores direct current (DC) electrical -- A medium that stores direct current (DC) electrical energy. energy.

• Inverter Inverter -- An electrical device that changes direct current to alternating -- An electrical device that changes direct current to alternating current (AC) to operate loads that require alternating current. current (AC) to operate loads that require alternating current.

• DC Loads DC Loads -- Appliances, motors and equipment powered by direct current. -- Appliances, motors and equipment powered by direct current. • AC Loads AC Loads -- Appliances, motors and equipment powered by alternating -- Appliances, motors and equipment powered by alternating

current.current.

A solar collector is a device for extracting the energy of the sun directly into a more usable or storable form. The energy in sunlight is in the form of electromagnetic radiation from the infrared (long) to the ultraviolet (short) wavelengths. The solar energy striking the earth's surface at any one time depends on weather conditions, as well as location and orientation of the surface, but overall, it averages about 1000 watts per square meter on a clear day with the surface directly perpendicular to the sun's rays.

A solar collector is a device for extracting the energy of the sun directly into a more usable or storable form. The energy in sunlight is in the form of electromagnetic radiation from the infrared (long) to the ultraviolet (short) wavelengths. The solar energy striking the earth's surface at any one time depends on weather conditions, as well as location and orientation of the surface, but overall, it averages about 1000 watts per square meter on a clear day with the surface directly perpendicular to the sun's rays.

A solar panel (module) is made up a number of solar cells. Solar cells are A solar panel (module) is made up a number of solar cells. Solar cells are

generally made from thin wafers of silicon, the second most abundant generally made from thin wafers of silicon, the second most abundant

substance on earth, the same substance that makes up sand. To make the substance on earth, the same substance that makes up sand. To make the

wafers, the silicon is heated to extreme temperatures, and chemicals, usually wafers, the silicon is heated to extreme temperatures, and chemicals, usually

boron and phosphorous, are added. The addition of these chemicals makes boron and phosphorous, are added. The addition of these chemicals makes

the silicon atoms unstable (their electrons less tightly held). When photons of the silicon atoms unstable (their electrons less tightly held). When photons of

sunlight hit a solar panel, some are absorbed into the solar cells, where their sunlight hit a solar panel, some are absorbed into the solar cells, where their

energy knocks loose some of the modified silicon's electrons. These loose energy knocks loose some of the modified silicon's electrons. These loose

electrons are forced by electric fields in the PV panel to flow along wires that electrons are forced by electric fields in the PV panel to flow along wires that

have been placed within the cells. This flow of electrons through the wires is have been placed within the cells. This flow of electrons through the wires is

electricity, and will provide power for whatever load we attach (a calculator, a electricity, and will provide power for whatever load we attach (a calculator, a

light bulb, a satellite, etc.) light bulb, a satellite, etc.)

Solar thermal energy refers to harnessing the sun's light to

produce heat. Heat results when photons, packets of light

energy, strike the atoms composing a substance (water, your

body, asphalt), exciting them. Solar thermal technologies include

passive solar systems for heating (or cooling!) buildings; flat plate

solar collectors, often used for providing households with hot

water; and solar concentrator power systems. These systems,

also known as solar thermal power plants, use the sun's heat to

create steam, which then turns a turbine and produces

electricity. (Fossil fuel burning power plants also produce

electricity by first creating steam in order to turn a turbine.)

Solar thermal energy refers to harnessing the sun's light to

produce heat. Heat results when photons, packets of light

energy, strike the atoms composing a substance (water, your

body, asphalt), exciting them. Solar thermal technologies include

passive solar systems for heating (or cooling!) buildings; flat plate

solar collectors, often used for providing households with hot

water; and solar concentrator power systems. These systems,

also known as solar thermal power plants, use the sun's heat to

create steam, which then turns a turbine and produces

electricity. (Fossil fuel burning power plants also produce

electricity by first creating steam in order to turn a turbine.)

Photovoltaics is one form of solar energy. The term solar energy can refer to something as simple the energy gathered in your parked, sealed car (your solar collector) and converted into heat. Solar energy is often used to heat houses directly through passive means (sun enters window, room warms). Solar energy is also often used to heat water (a solar collector is mounted in direct sunlight, which warms a heat transfer fluid, which in turn heats the water in your hot water tank). Photovoltaics refers specifically to the practice of converting the sun's energy directly into electricity using photovoltaic cells. Photovoltaic cells are often referred to as PV cells or solar cells.

Photovoltaics is one form of solar energy. The term solar energy can refer to something as simple the energy gathered in your parked, sealed car (your solar collector) and converted into heat. Solar energy is often used to heat houses directly through passive means (sun enters window, room warms). Solar energy is also often used to heat water (a solar collector is mounted in direct sunlight, which warms a heat transfer fluid, which in turn heats the water in your hot water tank). Photovoltaics refers specifically to the practice of converting the sun's energy directly into electricity using photovoltaic cells. Photovoltaic cells are often referred to as PV cells or solar cells.