The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

The amount of energy that a building absorbs due to solar energy striking its exterior and conducting to the interior or passing through windows and being absorbed by materials in the building.

The process of distilling (purifying) water using solar energy. Water can be placed in an air tight solar collector with a sloped glazing material, and as it heats and evaporates, distilled water condenses on the collector glazing, and runs down where it ...

A curve illustrating the variation or spectral irradiance with wavelength.

Energy available due to position.

The ratio of energy reflected from a surface in a given waveband to the energy incident in that waveband.

The angle between a line from a point on the earth's surface to the center of the solar disc, and a line extending horizontally from the point.

The process of distributing electricity; usually defines that portion of an electrical utility's power lines between a utility's power pole and transformer and a customer's point of connection/meter.

A solar photovoltaic device that produces a specified power output under defined test conditions, usually composed of groups of solar cells connected in series, in parallel, or in series-parallel combinations.

The amount of power per unit area of a free windstream.

An interior or exterior movable panel that operates on hinges or slides into place, used to protect windows or provide privacy.

The use of solar thermal energy or solar electricity to power a cooling appliance. There are five basic types of solar cooling technologies: absorption cooling, which can use solar thermal energy to vaporize the refrigerant; desiccant cooling, which can u ...

The gas resulting from the combustion of a fuel that is emitted to the flue.

The apparent angle of the sun north or south of the eath's equatorial plane. The earth's rotation on its axis causes a daily change in the declination.

A federally funded institute, created by the Solar Energy Research, Development and Demonstration Act of 1974, that conducted research and development of solar energy technologies. Became the National Renewable Energy Laboratory (NREL) in 1991.

The amount of solar radiation, both direct and diffuse, received at any location.

An apparatus that replicates the solar spectrum, and used for testing solar energy conversion devices.

The angle between the sun's apparent position in the sky and true south, as measured on a horizontal plane.

A device used to collect, absorb, and transfer solar energy to a working fluid.

Solar energy conversion technologies that convert solar energy to electricity, by heating a working fluid to power a turbine that drives a generator. Examples of these systems include central receiver systems, parabolic dish, and solar trough.