Photovoltaic Conversion Efficiency Terms +

(solar electricity technical terms applying to electricity, power generation, concentrating solar power, or CSP, solar heating, solar lighting, and solar electricity)

deep-cycle battery
A battery with large plates that can withstand many discharges to a low state-of-charge.
dendrite
A slender threadlike spike of pure crystalline material; such as, silicon.
dendritic web technique
A method for making sheets of polycrystalline silicon in which silicon dendrites are slowly withdrawn from a melt of silicon whereupon a web of silicon forms between the dendrites and solidifies as it rises from the melt and cools.
depletion zone
Same as cell barrier.

The term derives from the fact that this microscopically thin region is depleted of charge carriers (free electrons and hole).

depth of discharge; DOD
The ampere-hours removed from a fully charged cell or battery, expressed as a percentage of rated capacity.

For example, the removal of 25 ampere-hours from a fully charged 100 ampere-hours rated cell results in a 25 percent depth of discharge.

Under certain conditions, such as discharge rates lower than that used to rate the cell, depth of discharge can exceed 100 percent.

design month
The month having the combination of insolation and load that requires the maximum energy from the photovoltaic array.
diffuse insolation
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 radiation
Radiation received from the sun after reflection and scattering by the atmosphere and ground.
diffusion furnace
Furnace used to make junctions in semiconductors by diffusing dopant atoms into the surface of the material.
diffusion length
The mean distance a free electron or hole moves before recombining with another hole or electron.
diode
An electronic device that allows current to flow in one direction only.
direct beam radiation
Radiation received by direct solar rays.

Measured by a pyrheliometer with a solar aperture of 5.7 degrees to transcribe the solar disc.

direct current; DC
A type of electricity transmission and distribution by which electricity flows in one direction through the conductor, usually relatively low voltage and high current.

To be used for typical 120 volt or 220 volt household appliances, DC must be converted to alternating current, its opposite.

direct insolation
Sunlight falling directly upon a collector.

Opposite of diffuse insolation.

discharge
The withdrawal of electrical energy from a battery.
—The information for the entries in this unit were compiled primarily from data
provided in the following source:

"U.S. Department of Energy, Energy Efficiency and Renewable Energy"
consisting of definitions of many important terms having to do with electricity,
power generation, concentrating solar power (CSP), solar heating, solar lighting,
and solar electricity, also known as photovoltaic (PV).

Information was also compiled from the

Academic Press Dictionary of Science and Technology; Edited by Christopher Morris;
Academic Press; Harcourt Brace Jovanovich, Publishers; New York; 1992;
as well as,
McGraw-Hill Dictionary of Scientific and Technical Terms, 4th edition;
Sybil P. Parker, editor in chief; McGraw-Hill, Inc.; 1989.

Index of additional Scientific and Technological Topics.