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)

watt
The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt.

One watt equals 1/746 horsepower, or one joule per second. It is the product of voltage and current (amperage).

waveform
The shape of the phase power at a certain frequency and amplitude.
wet shelf life
The period of time that a charged battery, when filled with electrolyte, can remain unused before dropping below a specified level of performance.
window
A wide band gap material chosen for its transparency to light.

Generally used as the top layer of a photovoltaic device, the window allows almost all of the light to reach the semiconductor layers beneath.

work function
1. The minimum energy needed to remove an electron from the Fermi level (average energy of electrons) of a metal to infinity; usually expressed in electrovolts.
2. The energy difference between the Fermi level and vacuum zero.

The minimum amount of energy it takes to remove an electron from a substance into the vacuum.

The term Fermi refers to a unit of length, equal to 10-15 meters; used particularly in measuring nuclear distances.

zenith angle
1. The angle between the direction of interest (of the sun, for example) and the zenith (directly overhead).
2. The angle between the direction to the zenith (point of the celestial sphere vertically overhead) and the direction of a light ray.
—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.