The ratio of the minimum amount of work or energy required to perform a task to the amount actually used.

A type of water heater that circulates water through a heat exchanger in a boiler. The heated water then flows into an insulated storage tank.

The unit price of a good or service estimated from some base year in order to provide a consistent means of comparison.

A hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits. It generally contains a high percentage of methane, varying amounts of ethane, and inert gases; used as a heating fuel.

A device where sunlight concentrated onto a absorber heats it to a high temperature, and the thermal radiation emitted by the absorber is used as the energy source for a photovoltaic cell that is designed to maximize conversion efficiency at the wavelengt ...

A type of motor designed to operate precisely at the synchronous speed with no slip in the full-load speeds (rpm).

The amount of heat introduced to a space from all heat producing sources, such as building occupants, lights, appliances, and from the environment, mainly solar energy.

A seal used to prevent the leakage of fluids, and also maintain the pressure in an enclosure.

An instrument for measuring solar radiation.

Features and vegetation on the outside of or surrounding a building for aesthetics and energy conservation.

The amount of useful energy produced by a system less the amount of energy required to produce the fuel.

A solar energy conversion device that has a bowl shaped dish covered with a highly reflective surface that tracks the sun and concentrates sunlight on a fixed absorber, thereby achieving high temperatures, for process heating or to operate a heat (Stirlin ...

A salt, sodium sulfate decahydrate, that melts at 90 degrees Fahrenheit; a component of eutetic salts that can be used for storing heat.

The heat that flows from the building interior, through the building envelope to the outside environment.

A type of water heater that has no storage tank thus eliminating storage tank standby losses. Cold water travels through a pipe into the unit, and either a gas burner or an electric element heats the water only when needed.

A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel times 100 (for percent).

A building energy auditing technique for locating areas of low insulation in a building envelope by means of a thermographic scanner.

A WECS designed to produce electricity.

A house built using passive solar design techniques.

A mainly flat surface for transmitting radiant energy.