The discomfort or interference with visual perception when viewing a bright object against a dark background.

The wind speed and direction in an undisturbed flow.

A turbine that uses water pressure to rotate its blades; the primary types are the Pelton wheel, for high heads (pressure); the Francis turbine, for low to medium heads; and the Kaplan for a wide range of heads. Primarily used to power an electric generat ...

A naturally occurring radioactive gas found in the U.S. in nearly all types of soil, rock, and water. It can migrate into most buildings. Studies have linked high concentrations of radon to lung cancer.

The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy v ...

The ratio of the radiant energy (heat) leaving (being emitted by) a surface to that of a black body at the same temperature and with the same area; expressed as a number between 0 and 1.

The amount of energy derived from an electrical source per unit quantity of electricity passing through the source.2. Electrical potential; voltage.

A type of heating system where heat, resulting when electric current flows through an "element" or conductor, such as Nichrome, which has a high resistance, is radiated to a room.

The process of breaking down organic material; reduction of the net energy level and change in physical and chemical composition of organic material.

The wheeling of electric power in amounts and at prices that generally have been negotiated in longterm contracts between the generator and a distributor or very large consumer of power.

Under the First Law of Thermodynamics, efficiency is the ratio of work or energy output to work or energy input, and cannot exceed 100 percent. Efficiency under the Second Law of Thermodynamics is determined by the ratio of the theoretical minimum energy ...

The approximate energy producing capacity of a power plant, under specified conditions, usually during periods of highest load.

A term used for a wind energy conversion device that produces electricity; typically having one, two, or three blades.

The use of devices to limit or prevent the release of pollution into the atmosphere.

States that energy cannot be created or destroyed, but only changed from one form to another. First Law efficiency measures the fraction of energy supplied to a device or process that it delivers in its output. Also called the law of conservation of energ ...

A registered trademark name for houses built with tires, aluminum cans, and earth.

A thermal storage wall is a south-facing wall that is glazed on the outside. Solar heat strikes the glazing and is absorbed into the wall, which conducts the heat into the room over time. The walls are at least 8 in thick. Generally, the thicker the wall, ...

The first law states that energy can not be created or destroyed; the second law states that when a free exchange of heat occurs between two materials, the heat always moves from the warmer to the cooler material.

The transfer of heat through matter or space by means of electromagnetic waves.

A statement of the electric rate(s), terms, and conditions for electricity sale or supply.