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)

discharge factor
A number equivalent to the time in hours during which a battery is discharged at constant current usually expressed as a percentage of the total battery capacity; for example, C/5 indicates a discharge factor of 5 hours. Related to discharge rate.
discharge rate
The rate, usually expressed in amperes or time, at which electrical current is taken from the battery.
disconnect
Switch gear used to connect or disconnect components in a photovoltaic system.
distributed energy resources; DER
A variety of small, modular power-generating technologies that can be combined with energy management and storage systems and used to improve the operation of the electricity delivery system, whether or not those technologies are connected to an electricity grid.
distributed generation
A popular term for localized or on-site power generation.
distributed power
Generic term for any power supply located near the point where the power is used. Opposite of central power. See stand-alone systems.
distributed systems
Systems that are installed at or near the location where the electricity is used, as opposed to central systems that supply electricity to grids.

A residential photovoltaic system is a distributed system.

donor
In a photovoltaic device, an n-type dopant, such as phosphorus, that puts an additional electron into an energy level very near the conduction band; this electron is easily exited into the conduction band where it increases the electrical conductivity over than of an undoped semiconductor.
donor level
The level that donates conduction electrons to the system.
dopant
A chemical element (impurity) added in small amounts to an otherwise pure semiconductor material to modify the electrical properties of the material.

An n-dopant introduces more electrons; a p-dopant creates electron vacancies (holes).

doping
The addition of dopants to a semiconductor.
downtime
Time when the photovoltaic system cannot provide power for the load. Usually expressed in hours per year or that percentage.
dry cell
A cell (battery) with a captive electrolyte.

A primary battery that cannot be recharged.

duty cycle
The ratio of active time to total time. Used to describe the operating regime of appliances or loads in photovoltaic systems.
duty rating
The amount of time an inverter (power conditioning unit) can produce at full rated power.
—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.