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  • absorbed glass mat agm
    Absorbed glass mat (AGM) is a fibrous silica glass mat to suspend the electrolyte in batteries. This mat provides pockets that assist in the recombination gasses generated during charging back into water.   VRLA battery From Wikipedia, the free encyclopedia 12 Volt VRLA Battery A VRLA battery (valve-regulated lead-acid battery), more commonly known as a sealed […]
  • Absorption
    Absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – gas, liquid or solid material. This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, not by the surface (as in the case for adsorption). A more […]
  • alternating current AC
    Alternating Current AC Electric current in which the direction of flow is reversed at frequent intervals, usually 100 or 120 times per second (50 or 60 cycles per second or 50//60 Hz).   Alternating current AC From Wikipedia, the free encyclopedia “Effective power” redirects here. For the iOS 8 bug, see SpringBoard § “effective. Power” […]
  • altitude
    Altitude is the angle between the horizon (a horizontal plane) and the sun’s position in the sky, measured in degrees.   Altitude or height (sometimes known as depth) is defined based on the context in which it is used (aviation, geometry, geographical survey, sport, and many more). As a general definition, altitude is a distance […]
  • amorphous silicon
    Amorphous silicon is a non-crystalline semiconductor material that has no long-range order, often used in thin film photovoltaic modules. Used as semiconductor material for a-Si solar cells, or thin-film silicon solar cells, it is deposited in thin films onto a variety of flexible substrates, such as glass, metal and plastic. Amorphous silicon cells generally feature […]
  • ampere (A)
    An ampere is the unit for the electric current; the flow of electrons. One amp is 1 coulomb passing in one second. One amp is produced by an electric force of 1 volt acting across a resistance of 1 ohm. Sometimes this is abbreviated as I for intensity. The ampere is equivalent to one coulomb […]
  • ampere-hour (Ah)
    Ampere-hour (Ah) is the quantity of electrical energy equal to the flow of one ampere of current over time. Typically used to quantify battery bank capacity. The ampere-hour is frequently used in measurements of electrochemical systems such as electroplating and incorrectly, the ‘capacity’ of electrical batteries (a battery constituent material’s specific capacity is commonly expressed […]
  • angle of incidence
    The angle of incidence is the angle which references the sun’s radiation striking a surface. It is the angle between a ray incident on a surface and the line perpendicular to the surface at the point of incidence, called the normal. Determining the angle of reflection with respect to a planar surface is trivial, but the computation […]
  • array
    A solar array is any number of photovoltaic modules connected together to provide a single electrical output at a specified voltage. Arrays are often designed to produce significant amounts of electricity. Photovoltaic system From Wikipedia, the free encyclopedia   (Redirected from Solar array) Photovoltaic power systems and components: Top: solar string inverter and other BOS components ·Solar array […]
  • autonomous system
    An autonomous system is a stand-alone PV system that has no back-up generating source. May or may not include storage batteries. Electricity is typically generated by one or more of the following methods: Photovoltaic system using solar panels Wind turbine Geothermal source Micro combined heat and power Micro hydro Diesel or biofuel generator Storage is […]
  • avoided cost
    An avoided cost (also known as net-metering) is the minimum amount an electric utility is required to pay an independent power producer, under the PURPA regulations of 1978, equal to the costs the utility calculates it avoids in not having to produce that power (usually substantially less than the retail price charged by the utility […]
  • azimuth
    An azimuth is an angular measurement in a spherical coordinate system. The vector from an observer (origin) to a point of interest isprojected perpendicularly onto a reference plane; the angle between the projected vector and a reference vector on the reference plane is called the azimuth. An example is the position of a star in the […]
  • balance of system (BOS)
    The balance of system (BOS) encompasses all components of a photovoltaic system other than the photovoltaic panels.[1] This includes wiring, switches, a mounting system, one or many solar inverters, a battery bank andbattery charger. The Balance of System components of a photovoltaic system, can be understood as balancing the DC power-generating subsystem of the solar […]
  • barrier energy
    The energy given up by an electron in penetrating the cell barrier, a measure of the electrostatic potential of the barrier.
  • base power
    Power generated by a utility unit that operates at a very high capacity factor.
  • baseline performance value
    Initial values of Isc, Voc, Pmp, Imp measured by the accredited laboratory and corrected to Standard Test Conditions, used to validate the manufacturer’s performance measurements provided with the qualification modules per IEEE 1262.
  • battery
    An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices.[1] A discharging battery has a positive terminal, or cathode, and a negative terminal, or anode.[2] The terminal marked negative is the source of electrons that when connected to an external circuit will flow and […]
  • battery capacity
    Battery Capacity and discharge The battery capacity is the amount of electric charge it can deliver at the rated voltage. The more electrode material contained in the cell the greater its capacity. A small cell has less capacity than a larger cell with the same chemistry, although they develop the same open-circuit voltage.[30] Capacity is measured […]
  • battery cell
    An electrochemical or battery cell is a device capable of either generating electrical energy from chemical reactions or facilitating chemical reactions through the introduction of electrical energy. A common example of an electrochemical cell is a standard 1.5-volt cell meant for consumer use. This type of device is known as a single Galvanic cell. A […]
  • battery cycle life
    The number of cycles, to a specified depth of discharge, that a cell or battery can undergo before failing to meet its specified capacity or efficiency performance criteria.
  • battery self-discharge
    Battery self-discharge is a phenomenon in batteries in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes. Self-discharge decreases the shelf-life of batteries and causes them to initially have less than a full charge when actually put to use. How fast self-discharge in a battery occurs is […]
  • battery state of charge
    Battery state of charge (SOC) is the equivalent of a fuel gauge for the battery pack in a battery electric vehicle (BEV), hybrid vehicle (HV), or plug-in hybrid electric vehicle (PHEV). The units of SOC are percentage points (0% = empty; 100% = full). An alternate form of the same measure is the depth of […]
  • Bell Labs
    Nokia Bell Labs (formerly named AT&T Bell Laboratories, Bell Telephone Laboratories and Bell Labs) is an American research and scientific development company, owned by Finnish company Nokia. Its headquarters are located in Murray Hill, New Jersey, in addition to other laboratories around the rest of the United States and in other countries. The historic laboratory […]
  • blocking diode
    In electronics, a blocking diode is a two-terminal electronic component that conducts primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance to the flow of current in one direction, and high (ideallyinfinite) resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a […]
  • boron (B)
    Boron is a metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth’s crust.[12] Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate […]
  • British thermal unit (Btu)
    The British thermal unit (BTU or Btu) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit. One four-inch wooden kitchen match consumed completely generates approximately 1 BTU. In science and engineering, the joule, […]
  • building-integrated photovoltaics (BIPV)
    Building-integrated photovoltaics (BIPV) are photovoltaic materials that are used to replace conventional building materials in parts of the building envelope such as the roof, skylights, or facades.[1] They are increasingly being incorporated into the construction of new buildings as a principal or ancillary source of electrical power, although existing buildings may be retrofitted with similar […]
  • bypass diode
    The destructive effects of hot-spot heating may be circumvented through the use of a bypass diode. A diode is connected in parallel, but with opposite polarity, to a solar cell as shown below. Under normal operation, each solar cell will be forward biased and therefore the bypass diode will be reverse biased and will effectively […]
  • cadmium (Cd)
    Cadmium is a chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefersoxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals. […]
  • cadmium telluride (CdTe)
    Cadmium telluride (CdTe) is a stable crystalline compound formed from cadmium and tellurium. It is mainly used as the semiconducting material in cadmium telluride photovoltaics and an infrared optical window. It is usually sandwiched with cadmium sulfide to form a p-n junction solar PV cell. Typically, CdTe PV cells use a n-i-p structure. Applications[edit] See […]
  • capacity factor
    The net capacity factor of a power plant is the ratio of its actual output over a period of time, to its potential output if it were possible for it to operate at full nameplate capacity continuously over the same period of time. To calculate the capacity factor, take the total amount of energy the […]
  • Carbon Footprint
    A carbon footprint is historically defined as the total set of greenhouse gas emissions caused by an individual, event, organisation, or product, expressed as carbon dioxide equivalent.[1] In most cases, the total carbon footprint cannot be exactly calculated because of inadequate knowledge of and data about the complex interactions between contributing processes, especially which including […]
  • cathodic protection
    Cathodic protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.[1] A simple method of protection connects the metal to be protected to a more easily corroded “sacrificial metal” to act as the anode. The sacrificial metal then corrodes instead of the […]
  • cell
    A solar cell, or photovoltaic cell is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.[2] It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light. Solar cells […]
  • cell barrier
    A very thin region of static electric charge along the interface of the positive and negative layers in a photovoltaic cell. The barrier inhibits the movement of electrons from one layer to the other, so that higher-energy electrons from one side diffuse preferentially through it in one direction, creating a current and thus a voltage […]
  • cell junction
    A cell junction is formed when two types of semiconductors, n- type (excess electrons) and p- type (excess holes), come into contact. The term cell junction refers to the joint interface and the immediate surrounding area of the two semiconductors. If the joint is made by two separate semiconductor crystals, this is a rough interface known […]
  • central power
    The generation of electricity in large power plants with distribution through a network of transmission lines (grid) for sale to a number of users. Opposite of distributed power.
  • charge controller
    A charge controller, charge regulator or battery regulator limits the rate at which electric current is added to or drawn from electric batteries.[1] It prevents overcharging and may protect against overvoltage, which can reduce battery performance or lifespan, and may pose a safety risk. It may also prevent completely draining (“deep discharging”) a battery, or […]
  • charge rate
    The current applied to a cell or battery to restore its available capacity.
  • Charles Fritts
    Charles Fritts (1850 – 1903[1]) was the American inventor credited with creating the first working Selenium Cell in 1883. The world’s first rooftop solar array, using Fritts’ selenium cells, was installed in 1884 on a New York City rooftop.
  • chemical vapor deposition (CVD)
    Chemical vapor deposition (CVD) is a chemical process used to produce high quality, high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer(substrate) is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. […]
  • cleavage of lateral epitaxial films for transfer (CLEFT)
    A process for making inexpensive GaAs photovoltaic cells in which a thin film of GaAs is grown atop a thick, single-crystal GaAs (or other suitable material) substrate and then is cleaved from the substrate and incorporated into a cell, allowing the substrate to be reused to grow more thin-film GaAs.
  • coal
    Coal (Old English col; meaning “mineral of fossilized carbon” since the thirteenth century) is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature […]
  • combined collector
    A photovoltaic device or module that provides useful heat energy in addition to electricity.
  • compact fluorescent lamps
    A compact fluorescent lamp (CFL), also called compact fluorescent light, energy-saving light, and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent lamp; some types fit into light fixtures formerly used for incandescent lamps. The lamps use a tube which is curved or folded to fit into the space of an incandescent bulb, […]
  • concentrator
    A solar concentrator uses lenses, called Fresnel lenses, which take a large area of sunlight and direct it towards a specific spot by bending the rays of light and focusing them. Some people use the same principle when they use a magnifying lens to focus the Sun’s rays on a pile of kindling or paper […]
  • conversion efficiency
    Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be electric power, mechanical work, light(radiation), or heat.[citation needed] Output energy is always lower than input energy Overview[edit] Energy conversion efficiency is not defined […]
  • copper indium gallium diselenide (CuInSe2 or CIS)
    Copper indium gallium diselenide (CIGS) is a I–III–VI2 semiconductor material composed of copper, indium, gallium, and selenium. The material is a solid solution of copper indium selenide (often abbreviated “CIS”) and copper gallium selenide. It has a chemical formula of CuInxGa(1-x)Se2 where the value of x can vary from 1 (pure copper indium selenide) to […]
  • crystalline silicon
    Crystalline silicon (c-Si) is the crystalline forms of silicon, either multicrystalline silicon (multi-Si) consisting of small crystals, or monocrystalline silicon (mono-Si), a continuous crystal. Crystalline silicon is the dominant semiconducting material used in photovoltaic technology for the production of solar cells. These cells are assembled into solar panels as part of a photovoltaic system to […]
  • current
    An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in aplasma.[1] The SI unit for measuring an electric current is the ampere, which […]
  • current at maximum power (Imp)
    The current at which maximum power is available from a module. [UL 1703]
  • cycle life
    The cycle life is the number of discharge-charge cycles that a battery can tolerate under specified conditions before it fails to meet specified criteria as to performance (e.g., capacity decreases to 80-percent of the nominal capacity). A charge cycle life is the process of charging a rechargeable battery and discharging it as required into a load. […]
  • Czochralski process
    The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and synthetic gemstones. The process is named after Polish scientist Jan Czochralski,[1] who invented the method in 1916 while investigating the crystallization rates of metals.[2] He […]
  • days of autonomy
    The number of consecutive days a stand-alone system battery bank will meet a defined load without solar energy input.
  • DC to DC converter
    From Wikipedia, the free encyclopedia  A DC to DC converter is an electronic circuit or electromechanical device that converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from very low (small batteries) to very high (high-voltage power transmission). History[edit] See also: […]
  • deep cycle battery
    From Wikipedia, the free encyclopedia A deep cycle battery is a lead-acid battery designed to be regularly deeply discharged using most of its capacity. In contrast, starter batteries (e.g. most automotive batteries) are designed to deliver short, high-current bursts for cranking the engine, thus frequently discharging only a small part of their capacity. While a […]
  • deep discharge
    Discharging a battery to 50 percent or less of its full charge.
  • depth of discharge (DOD)
    Depth of Discharge (DOD) is an alternate method to indicate a battery‘s state of charge (SOC). The DOD is the complement of SOC: as the one increases, the other decreases. While the SOC units are percent points (0% = empty; 100% = full), DOD can use Ah units (e.g.: 0 = full, 50 Ah = […]
  • design month
    The month having the combination of insolation and load that requires the maximum energy from the array.
  • Diesel Generator
    A diesel generator is the combination of a diesel engine with an electric generator (often an alternator) to generate electrical energy. This is a specific case of engine-generator. A diesel compression-ignition engine is usually designed to run on diesel fuel, but some types are adapted for other liquid fuels or natural gas. Diesel generating sets […]
  • diffuse insolation
    Diffuse insolation is sunlight received indirectly as a result of scattering due to clouds, fog, haze, dust, or other obstructions in the atmosphere. Opposite of direct insolation. Diffuse sunlight (B), reflected from clouds, the ground, and nearby objects, and direct sunlight (A) falling onto flat-plate solar panels. Credit: US Dept. of Energy
  • diode
    From Wikipedia, the free encyclopedia In electronics, a diode is a two-terminal electronic component that conducts primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance to the flow of current in one direction, and high (ideally infinite) resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece […]
  • direct current (DC)
    From Wikipedia, the free encyclopedia Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, power supplies, thermocouples, solar cells, or dynamos. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as […]
  • direct insolation
    From Wikipedia, the free encyclopedia Direct insolation is the solar insolation measured at a given location on Earth with a surface element perpendicular to the Sun’s rays, excluding diffuse insolation (the solar radiation that is scattered or reflected by atmospheric components in the sky). Direct insolation is equal to the solar irradiance above the atmosphere […]
  • discharge rate
    The rate, usually expressed in amperes over time, at which electrical current is taken from the battery.
  • disconnect
    Switch gear used to connect or disconnect components of a PV system for safety or service.
  • distributed power
    Generic term for any power supply located near the point where the power is used. Opposite of central power. See `stand-alone’; `remote site.’
  • dopant
    From Wikipedia, the free encyclopedia A dopant, also called a doping agent, is a trace impurity element that is inserted into a substance (in very low concentrations) to alter the electrical or optical properties of the substance. In the case of crystalline substances, the atoms of the dopant very commonly take the place of elements […]
  • doping
    The addition of dopants to a semi- conductor.
  • duty cycle
    From Wikipedia, the free encyclopedia A duty cycle is the percentage of one period in which a signal or system is active.[1][2][3] A period is the time it takes for a signal to complete an on-and-off cycle. As a formula, a duty cycle may be expressed as: {displaystyle D={frac {T}{P}}times 100%}[2] where {displaystyle D} is […]
  • edge-defined film-fed growth (EFG)
    A method for making sheets of polycrystalline silicon in which molten silicon is drawn upward by capillary action through a mold.
  • efficiency
    From Wikipedia, the free encyclopedia  The efficiency of an entity (a device, component, or system) in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed (a fractional expression), typically denoted by the Greek letter small Eta (η – ήτα). {displaystyle mathrm {Efficiency} ={frac {mathrm {Useful power output} […]
  • electric circuit
    From Wikipedia, the free encyclopedia An electric circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly […]
  • electric current
    From Wikipedia, the free encyclopedia An electric current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in aplasma.[1] The SI unit for measuring an electric […]
  • electrical grid
    From Wikipedia, the free encyclopedia An electrical grid is an interconnected network for delivering electricity from suppliers to consumers. It consists of generating stations that produce electrical power, high-voltage transmission lines that carry power from distant sources to demand centers, and distribution lines that connect individual customers.[1] Power stations may be located near a fuel […]
  • electrodeposition
    Electrolytic process in which a metal is deposited at the cathode from a solution of its ions.
  • electrolyte
    A liquid conductor of electricity in which flow of current takes place by migration of ions. The electrolyte for a lead-acid storage cell is an aqueous solution of sulfuric acid.
  • electron volt
    An energy unit equal to the energy an electron acquires when it passes through a potential difference of one volt; it is equal to 1.602 x 10 -19 volt.
  • energy
    The ability to do work. Stored energy becomes working energy when we use it.
  • energy audit
    A survey that shows how much energy you use in your house, apartment, or business. It can indicate your most intensive energy consuming appliances and even identify heating and cooling leaks that will help you find ways to use less energy.
  • energy density
    The ratio of energy available from a battery to its volume (Wh/1) or mass (Wh/kg).
  • energy pay back time
    The time required for any energy producing system or device to produce as much energy as was required in its manufacture.
  • equalization
    The process of mixing the electrolyte in batteries by periodically overcharging the batteries for a short period to refresh cell capacity.
  • fill factor
    The ratio of a photovoltaic cell’s actual power to its power if both current and voltage were at their maxima. A key characteristic in evaluating cell performance.
  • flat-plate PV
    Refers to a PV array or module that consists of nonconcentrating elements. Flat-plate arrays and modules use direct and diffuse sunlight, but if the array is fixed in position, some portion of the direct sunlight is lost because of oblique sun- angles in relation to the array.
  • float charge
    Float charge is the voltage required to counteract the self-discharge of the battery at a certain temperature.
  • float life
    Number of years that a battery can keep its stated capacity when it is kept at float charge (see float charge).
  • fossil fuels
    Fuels formed in the ground from the remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas, and coal are fossil fuels.
  • fuel
    Any material that can be burned to make energy.
  • gassing current
    Portion of charge current that goes into electrolytical production of hydrogen and oxygen from the electrolytic liquid in the battery. This current increases with increasing voltage and temperature.
  • gel-type battery
    Lead-acid battery in which the electrolyte is composed of a silica gel matrix.
  • Generator
    Electric generators transform kinetic energy into electricity. This is the most used form for generating electricity and is based on Faraday’s law. It can be seen experimentally by rotating a magnet within closed loops of a conducting material (e.g. copper wire). Almost all commercial electrical generation is done using electromagnetic induction, in which mechanical energy […]
  • gigawatt (GW)
    One billion watts. One million kilowatts. One thousand megawatts.
  • glazings
    Clear materials (such as glass or plastic) that allow sunlight to pass into solar collectors and solar buildings, trapping heat inside.
  • grain boundaries
    The boundaries where crystallites in a multicrystalline material meet.
  • grid
    See `Electrical grid.’
  • grid-connected
    A PV system in which the PV array acts like a central generating plant, supplying power to the grid.
  • grid-interactive
    See `Grid-connected (PV system).’
  • hybrid system
    A PV system that includes other sources of electricity generation, such as wind or fossil fuel generators.
  • I-V curve
    A graphical presentation of the current versus the voltage from a photovoltaic device as the load is increased from the short circuit (no load) condition to the open circuit (maximum voltage) condition. Typically measured at 1000 watts per square meter of solar insolation at a specific cell temperature. The shape of the curve characterizes cell […]
  • incident light
    Light that shines onto the surface of a solar cell or module.
  • infrared radiation
    Electromagnetic radiation whose wavelengths lie in the range from 0.75 micrometer to 1000 micrometers.
  • insolation
    Sunlight, direct or diffuse; from `incident solar radiation.’ Usually expressed in watts per square meter. Not to be confused with `insulation.’
  • insulation
    Materials that reduce the rate or slow down the movement of heat.
  • interconnect
    A conductor within a module or other means of connection which provides an electrical interconnection between the solar cells.
  • Inverter Input Circuit
    Inverter Input Circuit is defined as conductors between the inverter and the battery in stand-alone systems or the conductors between the inverter and the photovoltaic output circuits for electrical production and distribution network.
  • Inverter Output Circuit
    Inverter Output Circuit. Conductors between the inverter and an ac panelboard for stand-alone systems or the conductors between the inverter and the service equipment or another electric power production source, such as a utility, for electrical production and distribution network.
  • inverters
    Devices that convert DC electricity into AC electricity (single or multiphase), either for stand-alone systems (not connected to the grid) or for utility-interactive systems.
  • John Ericsson
    John Ericsson (born Johan) (July 31, 1803 – March 8, 1889) was a Swedish-American inventor, active in England and the United States, and regarded as one of the most influential mechanical engineers ever. Ericsson collaborated on the design of the steam locomotive Novelty, which competed in the Rainhill Trials on the Liverpool and Manchester Railway, […]
  • junction box
    An electrical box designed to be a safe enclosure in which to make proper electrical connections. On PV modules this is where PV strings are electrically connected.
  • Leonardo DaVinci
    Leonardo di ser Piero da Vinci , more commonly Leonardo da Vinci or simply Leonardo, was an Italian Renaissance polymath whose areas of interest included invention, painting, sculpting, architecture, science, music, mathematics, engineering, literature, anatomy, geology, astronomy, botany, writing, history, and cartography. He has been variously called the father of palaeontology, ichnology, and architecture, and […]
  • life cycle cost
    An estimate of the cost of owning and operating a system for the period of its useful life; usually expressed in terms of the present value of all lifetime costs.
  • line-commutated inverter
    An inverter that is tied to a power grid or line. The commutation of power (conversion from DC to AC) is controlled by the power line, so that, if there is a failure in the power grid, the PV system cannot feed power into the line.
  • load
    Anything in an electrical circuit that, when the circuit is turned on, draws power from that circuit.
  • maximum power point (MPP)
    The point on the current-voltage (I-V) curve of a module under illumination, where the product of current and voltage is maximum. For a typical silicon cell, this is at about 0.45 V.
  • maximum power point tracker (MPPT)
    Means of a power conditioning unit that automatically operates the PV generator at its MPP under all conditions.
  • megawatt (MW)
    One million watts; 1000 kilowatts.
  • module
    See `Photovoltaic Module.’
  • multicrystalline
    Material that is solidified at such as rate that many small crystals (crystallites) form. The atoms within a single crystallite are symmetrically arranged, whereas crystallites are jumbled together. These numerous grain boundaries reduce the device efficiency. A material composed of variously oriented, small individual crystals. (Sometimes referred to as polycrystalline or semicrystalline).
  • n-type semiconductor
    A semiconductor produced by doping an intrinsic semiconductor with an electron-donor impurity, for example phosphorous in silicon.
  • National Electric Code (NEC)
    The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Codes series published by the National Fire Protection Association (NFPA), a private trade association.[1] Despite the use of the term “national”, it […]
  • NEC
    An abbreviation for the National Electrical Code ® which contains safety guidelines and required practices for all types of electrical installations. Article 690 pertains to solar photovoltaic systems.
  • nominal operating cell temperature (NOCT)
    The reference cell (module) operating temperature presented on manufacturer’s literature. Generally the NOCT is referenced at 25°C, 77°F.
  • nominal voltage
    A reference voltage used to describe batteries, modules, or systems (ie. a 12-, 24- , or 48-volt battery, module or system).
  • nonrenewable fuels
    Fuels that cannot be easily made or renewed. We can use up nonrenewable fuels. Oil, natural gas, and coal are nonrenewable fuels.
  • ohm
    The unit of resistance to the flow of an electric current.
  • one-axis tracking
    A system capable of rotating about one axis, also referred to as single axis. These tracking systems usually follow the sun from east to west throughout the day.
  • open-circuit voltage (Voc)
    The maximum possible voltage across a photovoltaic cell or module; the voltage across the cell in sunlight when no current is flowing.
  • orientation
    Placement according to the compass directions, north, south, east, west.
  • P-Type silicon
    Semi-conductor grade silicon doped with the element boron giving it a positive bias.
  • p/n
    A semiconductor device structure in which the junction is formed between a p-type layer and an n- type layer.
  • panel
    See `photovoltaic panel.’
  • parallel connection
    A way of joining two or more electricity-producing devices such as PV cells or modules, or batteries by connecting positive leads together and negative leads together; such a configuration increases the current but the voltage is constant.
  • passive solar building
    A building that utilizes non- mechanical, non-electrical methods for heating , cooling and/or lighting.
  • peak load
    The maximum load, or usage, of electrical power occurring in a given period of time, typically a day. Also known as peak demand.
  • peak power
    Power generated by a utility unit that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.
  • peak sun hours
    The equivalent number of hours per day when solar irradiance averages 1000 w/m 2 (full sun).
  • Petroleum
    Petroleum (from Greek: petra: “rock” + oleum: “oil”. [1][2][3][4][5][6]) is a naturally occurring, yellow-to-black liquid found in geological formations beneath the Earth‘s surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation. It consists of hydrocarbons of various molecular weights and other organic compounds.[7] […]
  • phosphorous (P)
    A chemical element, atomic number 15, used as a dopant in making n- semiconductor layers.
  • Photoelectric effect
    The photoelectric effect is the emission of electrons or other free carriers when light is shone onto a material. Electrons emitted in this manner can be called photo electrons. The phenomenon is commonly studied in electronic physics, as well as in fields of chemistry, such as quantum chemistry or electrochemistry. In 1905, Albert Einstein published […]
  • photon
    A particle of light that acts as an individual unit of energy.
  • Photons
    A photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual photons). The photon has zero rest mass and always moves at the speed of light within a vacuum. Like all elementary particles, […]
  • photovoltaic (PV)
    Pertaining to the direct conversion of photons of sunlight into electricity.
  • photovoltaic array
    An interconnected system of PV modules that function as a single electricity- producing unit. The modules are assembled as a discrete structure, with common support or mounting. In smaller systems, an array can consist of a single module.
  • photovoltaic cell
    The smallest semiconductor element within a PV module to perform the immediate conversion of light into electrical energy (DC voltage and current).
  • photovoltaic conversion efficiency
    The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device.
  • photovoltaic module
    The smallest environmentally protected, essentially planar assembly of solar cells and ancillary parts, such as interconnections, terminals, [and protective devices such as diodes] intended to generate DC power under unconcentrated sunlight. The structural (load carrying) member of a module can either be the top layer (superstrate) or the back layer (substrate).
  • Photovoltaic Output Circuit
    Photovoltaic Output Circuit is defined as the circuit conductors between the photovoltaic source circuit(s) and the inverter or dc utilization equipment.
  • photovoltaic panel
    Often used interchangeably with PV module (especially in one-module systems), but more accurately used to refer to a physically connected collection of modules (i.e., a laminate string of modules used to achieve a required voltage and current).
  • photovoltaic peak watt
    Maximum rated output of a cell, module, or system. Typical rating conditions are 0.645 watts per square inch (1000 watts per square meter) of sunlight, 68 degrees F (20 degrees C) ambient air temperature and 6.2 x 10 -3 mi/s (1 m/s) wind speed.
  • Photovoltaic Source Circuit
    Photovoltaic Source Circuit is defined as the circuits between modules and from modules to the common connection point(s) of the dc system.
  • photovoltaic system
    A complete set of components for converting sunlight into electricity by the photovoltaic process, including the array and balance of system components.
  • physical vapor deposition
    A method of depositing thin semiconductor films. With this method, physical processes, such as thermal evaporation or bombardment of ions, are used to deposit elemental semiconductor material on a substrate.
  • polycrystalline
    See `Multicrystalline.’
  • power conditioning equipment
    Electrical equipment, or power electronics, used to convert power from a photovoltaic array into a form suitable for subsequent use. A collective term for inverter, converter, battery charge regulator, and blocking diode.
  • power factor
    The ratio of the average power and the apparent volt-amperes.
  • pulse-width-modulated wave inverter (PWM)
    PWM inverters are the most expensive, but produce a high quality of output signal at minimum current harmonics. The output voltage is very close to sinusoidal.
  • PV
    Abbreviation for photovoltaic.
  • Pyranometer
    A pyranometer is a type of actinometer used for measuring solar irradiance on a planar surface and it is designed to measure the solar radiation flux density (W/m2) from the hemisphere above within a wavelength range 0.3 μm to 3 μm. The name pyranometer stems from the Greek words πῦρ (pyr), meaning “fire”, and ἄνω […]
  • quad
    A measure of energy equal to one trillion BTUs; an energy equivalent to approximately 172 million barrels of oil.
  • qualification test
    A procedure applied to a selected set of PV modules involving the application of defined electrical, mechanical, or thermal stress in a prescribed manner and amount. Test results are subject to a list of defined requirements.
  • Rankine Cycle
    The Rankine cycle is a model that is used to predict the performance of steam turbine systems, though the theoretical principle also applies to reciprocating engines such as steam locomotives. The Rankine cycle is an idealized thermodynamic cycle of a heat engine that converts heat into mechanical work while undergoing phase change. The heat is […]
  • rectifier
    A device that converts AC to DC. See inverter.
  • remote site
    Site which is not located near the utility grid.
  • remote systems
    Systems located away from the utility grid.
  • resistance (R)
    The property of a conductor which opposes the flow of an electric current resulting in the generation of heat in the conducting material. The unit of resistance is ohms.
  • satellite power system (SPS)
    Concept for providing large amounts of electricity for use on the Earth from one or more satellites in geosynchronous Earth orbit. A very large array of solar cells on each satellite would provide electricity, which would be converted to microwave energy and beamed to a receiving antenna on the ground. There, it would be reconverted […]
  • Selenium
    Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium. It rarely occurs in its elemental state or as pure ore compounds in the Earth’s crust. Selenium was discovered in 1817 by […]
  • semiconductor
    Any material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, gallium arsenide, copper indium dislenide, and cadmium telluride, are uniquely suited to the photovoltaic conversion process.
  • semicrystalline
    See `Multicrystalline.’
  • series connection
    A way of joining electrical equipment by connecting positive leads to negative leads; such a configuration increases the voltage while current remains the same.
  • series regulator
    Type of battery charge regulator where the charging current is controlled by a switch connected in series with the PV module or array.
  • shelf life of batteries
    The length of time, under specified conditions, that a battery can be stored so that it keeps its guaranteed capacity.
  • short-circuit current (Isc)
    The current flowing freely from a photovoltaic cell through an external circuit that has no load or resistance; the maximum current possible.
  • shunt regulator
    Type of a battery charge regulator where the charging current is controlled by a switch connected in parallel with the PV generator. Overcharging of the battery is prevented by shorting the PV generator.
  • silicon (Si)
    A chemical element, atomic number 14, semimetallic in nature, dark gray, an excellent semiconductor material. A common constituent of sand and quartz (as the oxide). Crystallizes in face- centered cubic lattice-like a diamond. The most common semiconductor material used in making photovoltaic devices.
  • sine wave inverter
    An inverter that produces utility- quality, sine wave power forms.
  • single-crystal material
    A material that is composed of a single crystal or a few large crystals.
  • solar cell
    See `Photovoltaic cell.’
  • solar constant
    The strength of sunlight; 1353 watts per square meter in space and about 1000 watts per square meter at sea level at the equator at solar noon.
  • solar energy
    Energy from the sun. For example, the heat that builds up in your car when the windows are closed is solar energy.
  • solar noon
    That moment of the day that divides the daylight hours for that day exactly in half. To determine solar noon, calculate the length of the day from the time of sunset and sunrise and divide by two. The moment the sun is highest in the sky.
  • solar spectrum
    The total distribution of electromagnetic radiation emanating from the sun.
  • solar thermal electric
    Method of producing electricity from solar energy by using focused sunlight to heat a working fluid, which in turn drives a turbogenerator.
  • solar-grade silicon
    Intermediate-grade silicon used in the manufacture of solar cells. Less expensive than electronic-grade silicon.
  • square wave inverter
    The inverter consists of a DC source, four switches, and the load. The switches are power semiconductors that can carry a large current and withstand a high voltage rating. The switches are turned on and off at a correct sequence, at a certain frequency. The square wave inverter is the simplest and the least expensive […]
  • Staebler-Wronski effect
    The tendency of amorphous silicon photovoltaic devices to lose efficiency upon initial exposure to light; named for Dr. David Staebler and Dr. Christopher Wronski; work performed at RCA.
  • stand-alone
    An autonomous or hybrid photovoltaic system not connected to a grid. Some stand-alone systems require batteries or some other form of storage. Also, stand-alone PV system.
  • stand-off mounting
    Technique for mounting a PV array on a sloped roof, which involves mounting the modules a short distance above the pitched roof and tilting them to the optimum angle. This promotes air flow to cool the modules.
  • standard reporting conditions (SRC)
    A fixed set of conditions (including meteorological) to which the electrical performance data of a photovoltaic module is translated from the set of actual test conditions [ASTM E 1036].
  • standard test conditions (STC)
    Conditions under which a module is typically tested in a laboratory: (1) Irradiance intensity of 1000 W/square meter (0.645 watts per square inch), AM1.5 solar reference spectrum, and (3) a cell (module) temperature of 25 °C, plus or minus 2 °C (77 °F, plus or minus 3.6 °F).
  • state of charge (SOC)
    The available capacity remaining in a cell or battery, expressed as a percentage of the rated capacity. For example, if 25 amp-hours have been removed from a fully charged 100 amp-hour cell, the state of charge is 75 percent.
  • Subsidy
    A subsidy is a form of financial aid or support extended to an economic sector (or institution, business, or individual) generally with the aim of promoting economic and social policy.[1] Although commonly extended from government, the term subsidy can relate to any type of support – for example from NGOs or as implicit subsidies. Subsidies […]
  • substrate
    The physical material upon which a photovoltaic cell is made.
  • sulfation
    A condition that afflicts unused and discharged batteries; large crystals of lead sulfate grow on the plate, instead of the usual tiny crystals, making the battery extremely difficult to recharge.
  • superconductivity
    The pairing of electrons in certain materials that, when cooled below a critical temperature, cause the material to lose all resistance to electricity flow. Superconductors can carry electric current without any energy losses.
  • superstrate
    The covering on the sun side of a PV module, providing protection for the PV materials from impact and environmental degradation while allowing maximum transmission of the appropriate wavelengths of the solar spectrum.
  • surge
    The momentary start-up condition of a motor requiring a large amount of electrical current.
  • surge capacity
    The ability of an inverter or generator to deliver high currents momentarily required when starting a motor.
  • temperature compensation
    An allowance made in charge controller set points for changing battery temperatures.
  • thermal electric
    Electric energy derived from heat energy, usually by heating a working fluid, which drives a turbogenerator See `solar thermal electric.’
  • thermal mass
    Materials, typically masonry, that store heat in a passive solar home.
  • thin film
    A layer of semiconductor material, such as copper indium diselenide, cadmium telluride, gallium arsenide, or amorphous silicon, a few microns or less in thickness, used to make photovoltaic cells.
  • Thomas A. Edison
    Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman, who has been described as America’s greatest inventor.[2] He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb. Dubbed “The Wizard of Menlo Park”,[3] he […]
  • tilt angle
    Angle of inclination of collector as measured in degrees from the horizontal. For maximum performance solar collectors/modules should be set at a perpendicular to the sun.
  • total harmonic distortion (thd)
    The measure of closeness in shape between a waveform and its fundamental component.
  • tracking PV array
    PV array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array points directly at the sun at all times. Tracking arrays use […]
  • transformer
    An electromagnetic device used to convert AC electricity, either to increase or decrease the voltage.
  • transmission lines
    Conductors used to transmit high-voltage electricity from the transformer to the electric distribution system.
  • trickle charge
    A charge at a low rate, balancing through self-discharge losses, to maintain a cell or battery in a fully charged condition.
  • two-axis tracking
    A system capable of rotating independently about two axes and following the sun’s orientation and height in the sky (e.g., vertical and horizontal).
  • ultraviolet (UV)
    Electromagnetic radiation in the wavelength range of 4 to 400 nanometers.
  • uninterruptible power supply (UPS)
    The designation of a power supply providing continuous uninterruptible service when a main power source is lost.
  • utility-interactive inverter
    An inverter that can function only when tied to the utility grid, and uses the prevailing line-voltage frequency on the utility line as a control parameter to ensure that the PV system’s output is fully synchronized with the utility power.
  • Vac
    Volts AC.
  • vacuum deposition
    Method of depositing thin coatings of a substance by heating it in a vacuum system.
  • vacuum evaporation
    The deposition of thin films of semiconductor material by the evaporation of elemental sources in a vacuum.
  • Vdc
    Volts DC.
  • Voc
    Open-circuit voltage.
  • volt (V)
    A unit of measure of the force, or `push,’ given the electrons in an electric circuit. One volt produces one ampere of current when acting against a resistance of one ohm.
  • voltage at maximum power (Vmp)
    The voltage at which maximum power is available from a module.
  • wafer
    A thin sheet of semiconductor material made by mechanically sawing it from a single-crystal or multicrystal ingot or casting.
  • watt (W)
    The unit of electric power, or amount of work. One ampere of current flowing at a potential of one volt produces one watt of power.
  • watt-hour (Wh)
    A quantity of electrical energy when one watt is used for one hour.
  • waveform
    The shape of the curve graphically representing the change in the AC signal voltage and current amplitude, with respect to time.