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S-W of solar technology terms
10/8/2008
S
Self-dischargeBatteries lose charge even when not in use. For many batteries, self-discharge rate increases as the battery ages.
Series connection
Electrical connection where the positive terminal of one device is attached to the negative terminal of the next in a series string; in this connection, the string voltage is the sum of the device voltages and the string current is limited to the current of the least productive device in the string.
Short-circuit current
Abbreviated Isc, refers to a photovoltaic (PV) device's current output when short-circuited.
Shunting path
A short circuit path within a solar cell that will lead to efficiency loss.
Solar cell
The smallest semiconductor device that can convert sunlight into electrical energy. Each silicon cell produces approximately half a volt, so many are wired in series to increase the voltage to significant levels.
Solar module
An assembly of solar cells in series or parallel to augment voltage and/or current.
Solar panel
A group of solar modules mechanically mounted on a single frame or structure.
Solar spectrum
The total distribution of electromagnetic radiant energy over the band of wavelengths present in solar radiation. The total energy received on a given surface, and how that energy is distributed among various wavelengths, depends on how much of the Earth's atmosphere light has traversed.
Standalone system
A power system not connected to the utility grid (mains.) Sometimes referred to as an autonomous system.
Standard operating conditions
Abbreviated SOC, a set of reference PV device measurement conditions consisting of irradiance of 0.8 kW/m², 20ºC ambient temperature, and average windspeed of 1 m/s, with the wind oriented parallel to the plane of the array, and all sides of the array fully exposed to the wind.
Standard test conditions
Abbreviated STC, a set of reference PV device measurement conditions consisting of irradiance of 1 kW/m², AM 1.5, and 25ºC cell temperature.
Standoff mount
A mounting system which supports a PV array above a roof surface.
State of charge
Abbreviated SOC, the percentage of energy in a battery referenced to its nominal full capacity.
Sulfation
The formation of lead sulfate crystals on the plates of a lead-acid battery. Normally used to refer to large sulfate crystals, rather than small crystals formed in normal battery operation, formed as a result of temperature cycling while the battery is in a partially charged state.
A power system not connected to the utility grid (mains.) Sometimes referred to as an autonomous system.
Standard operating conditions
Abbreviated SOC, a set of reference PV device measurement conditions consisting of irradiance of 0.8 kW/m², 20ºC ambient temperature, and average windspeed of 1 m/s, with the wind oriented parallel to the plane of the array, and all sides of the array fully exposed to the wind.
Standard test conditions
Abbreviated STC, a set of reference PV device measurement conditions consisting of irradiance of 1 kW/m², AM 1.5, and 25ºC cell temperature.
Standoff mount
A mounting system which supports a PV array above a roof surface.
State of charge
Abbreviated SOC, the percentage of energy in a battery referenced to its nominal full capacity.
Sulfation
The formation of lead sulfate crystals on the plates of a lead-acid battery. Normally used to refer to large sulfate crystals, rather than small crystals formed in normal battery operation, formed as a result of temperature cycling while the battery is in a partially charged state.
T
TexturingPart of the monocrystalline cell production process which helps to reduce the reflection of sunlight.
Thin-film cell
A solar cell formed by depositing thin layers of conductive and semiconductive materials, usually using a chemical vapour deposition (CVD) process. Also referred to as amorphous cells because they have no crystalline structure. Such cells use less material than cells sawn from crystalline ingots.
Two-axis tracking
A tracking system which follows the sun's azimuth and elevation.
U
Utility-interactiveA power system which interacts with the utility grid (mains), taking power from the grid to satisfy its loads as necessary, and returning power to the grid when not required by the loads.
V
VoltageMeasured in volts (V), the electrical potential between two points. One volt of potential causes one ampere of current to flow through a resistance of one ohm. The open-circuit voltage of a silicon solar cell is about half a volt; the operating voltage of a lead-acid cell is about two volts.
W
WaferA slice of silicon brick used to make a solar cell.