Facts About Photovoltaic Solar Panels
Learn some important facts about photovoltaic solar panels. The term photovoltaic or PV, refers to a type of cell used to convert sunlight into energy. Photovoltaic (PV) is a solar, renewable energy source. It is considered a viable alternative energy source to replace burning of fossil fuels. A photovoltaic system uses cells made of coated semiconductor material to directly convert sunlight into energy (electricity). PV is different from some solar systems that use sunlight to directly convert water to heated water. To best collect the needed sunlight, a PV system is designed to maximum the amount of sunlight exposure throughout the day. Some PV systems have panels that can be adjusted to collect more sunlight either manually or by tracking the sun automatically.
Photovoltaic PV Cell History
- In 1839 a French Scientist named Edmond Becquerel discovers that electricity is produced when two metal electrodes were placed in a liquid that promoted the conductivity of electricity. This is considered a breakthrough since it was the first photovoltaic experiment.
- From 1873-1876 three scientists discovered that an element called selenium, is a material that could produce an electrical charge with sunlight alone. Willoughby Smith first discovered this property of selenium. William Grylls Adams and Richard Evans Day were able to show that selenium could make electricity when it is exposed to light. The amount of power, however, was extremely small.
- In 1887 Heinrich Hertz studied the photoelectric effect. He recorded actual production and reception of electromagnetic (EM) waves when selenium is exposed to light.
- In 1905 Albert Einstein published his paper about the theory of relativity. His paper also included his research on the photoelectric effect.
- In 1918 a scientist from Poland named Jan Czochralski found a way to grow single-crystal silicon.
- In 1954 a major breakthrough in photovoltaic history occurred. Daryl Chapin, Gerald Pearson and Calvin Fuller develop the first silicon photovoltaic (PV) cell at Bell Telephone Labs. Finally, there was a PV cell capable of producing enough power to be useful. During its original research, the Bell Telephone Labs was able to increase the efficiency of the power output of a PV cell up to 11% efficiency.
Uses of Photovoltaic Cells
- For years PV technology has powered satellites in space, powered calculators, scales, and watches. Scientists were beginning to learn the facts about photovoltaic solar panels. With improvements in materials and technology, PV systems are becoming a better economic alternative to supplementing power produced from fossil fuels. This is particularly true in areas that have more direct sunlight such as the southern United States.
- A photovoltaic system requires several parts including the PV array, wiring to handle the produced electricity, an overcurrent protection system, a controller, batteries (if power will be stored), and an inverter to transform the produced electricity from DC to AC current. Household appliances and electronics devices such as TV’s, computers, and toasters run on AC power. The PV makes DC current. The DC to AC converted then allows homeowners to power standard devices with the solar power that is generated from their panels.
- Photovoltaic systems can be set up to completely power a house using either a battery system that stores energy for night use or by using net metering. Net metering is where the PV system is tied to the electrical grid. When excess power is produced by the PV installation, the power is allowed to be released into the grid. As the electricity is release the electric meter spins in the opposite direction, reversing any charges that occurred when the PV system did not produce enough electricity.
Types of Photovoltaic Cells used for Solar Panels
- There are 3 types of photovoltaic (PV) cells used for solar panel power generation. The 3 types of PV cells include thin film panels, monocrystalline panels and polycrystalline panels.
- Amorphous silicon (thin film) This type of solar cell generates relatively low power, made up of non-crystalline materials. Application of thin film cells can be made to flat, curved or even flexible surfaces allowing a wide array of uses such as roofing material, glass, or siding. The current efficiency of thin film solar cells is around 10%, but is improving.
- Single crystal (monocrystalline) This type of solar cell is the most efficient at converting sunlight to electricity. Each cell typically produces 0.5V and cell panels generally are produced with 36 or 72 cells producing 12-24 volts. Larger panels, however, are produced with up to 720 cells producing 240 volts. These type of cells are somewhat fragile and must be mounted in a rigid frame.
- Multicrystalline (polycrystalline) This type of panel is made up of cells cut from multiple crystals that are grown together. These type of panels cannot be damaged as easy as single crystal cells, but are also less efficient.