A measure of the efficacy (efficiency) of lamps. It indicates the amount of light (lumens) emitted by the lamp for each unit of electrical power (Watts) used.

The abrupt and large increase in electrical conductivity exhibited by some metals as the temperature approaches absolute zero.

The average time a minority carrier exists before recombination.

The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device.

A solar photovoltaic product that generally consists of groups of PV cells electrically connected together to produce a specified power output under standard test conditions, mounted on a substrate, sealed with an encapsulant, and covered with a protectiv ...

An exterior door that protects the primary door.

A heat exchanger that transfers heat contained in a liquid heat transfer fluid to another liquid.

A water heater that releases hot water from the top of the tank when a hot water tap is opened. To replace that hot water, cold water enters the bottom of the tank to ensure a full tank.

A hydrocarbon gas, C3H8, occurring in crude oil, natural gas, and refinery cracking gas. It is used as a fuel, a solvent, and a refrigerant. Propane liquefies under pressure and is the major component of liquefied petroleum (LPG).

A tubular material used to encase and protect one or more electrical conductors.

An electrochemical device that converts chemical energy directly into electricity.

A device used to maintain a specified humidity in a conditioned space.

The process of modifying a building's structure.

An empirical measure of the quantity of light. It is based upon the spectral sensitivity of the photosensors in the human eye under high (daytime) light levels. Photometrically it is the luminous flux emitted with a solid angle (1 steradian) by a point so ...

A type of hydroelectric facility that uses the river flow with very little alteration and little or no impoundment of the water.

An air conditioning system that has two ducts, one is heated and the other is cooled, so that air of the correct temperature is provided by mixing varying amounts of air from each duct.

A heat source, such as a space heater, used to provide more heat than that provided by a primary heating source.

The height above the ground that a horizontal axis wind turbine's hub is located.

The ratio of power produced by a wind energy conversion device to the power in a reference area of the free windstream.

The total amount of electricity produced by a power plant.