Solar Glossary

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Absorbed Glass Mat (AGM): A new version of battery that replaces gelled or liquid electrolytes with saturated absorbent glass mats. Even though it is costlier than the traditional liquid, it is more efficient and reliable.

Absorbers: These are the components of thermal solar power collectors. Their dark nature facilitates absorption of heat that is necessary to produce heat energy.

Active Solar heater: Solar powered space heating or water unit that circulates the hot air or water using fans or pumps.

Alternating Current: A current flowing first in one direction in a circuit, called the positive direction, then in reverse or negative direction, is Alternating Current (AC). It usually occurs 100-120 times/sec (termed as 50-60 cycles/sec or 50-60 Hertz).

American Wire Gauge / AWG: It is a standardized system of coding the sizes of electrical wires. The size of higher numbered wires is smaller. Mostly, the domestic wiring is in either 12-14 number wires. Some countries specify the gauge in millimeters.

Amorphous Semiconductor: It is a semiconductor of non-crystalline nature. Even though it is cheaper and convenient to produce instead of a crystalline one, it is lower in efficiency and durability. It is also known as thin film.

Ampere-hour / Amp-hr / Ah: It is a measure of electrical charge in amperes over a period of 1 hour. Solar power systems have a rating in amp-hour (Ah) for the deep cycle batteries.

Ampere/ amp / A: A unit of current, ampere, is defined as the current that flows through a conductor when 1 coulomb of charge flows in 1 second.

Angle of incidence: Refers to the angle between the incident ray and perpendicular to a surface. It is commonly applicable to the solar collectorメs aperture plane. Many recent solar panels contain only a marginal difference of 15 degrees in the power output.

Anti-reflection coating: A layer of material applied on the surface of photovoltaic cells, which reduces reflection of light and enhances light transmission.

Array: It is a group of photovoltaic units in a sequence, to give one electrical output. Such components are essential to boost the amount of electricity produced.

Autonomous system: It is a solitary photovoltaic system, with no external generator backup. It can be with or without storage batteries. The battery system caters to at least number of days of sufficient power supply without solar recharge. This minimum period could be 3 to 5 days using the Sun Belt and 5-10 days at other locations.

Azimuth: Refers to the angle formed between the north direction and the projection made by the surface perpendicular calculated in a horizontal plane. It is a clockwise measurement from the north. With respect to the photovoltaic array, 180ᄚ azimuth denotes that the array is facing south.