The point or outdoor temperature where the heating capacity of a heat pump matches the heating requirements of a building.

A charge for the maximum rate at which energy is used during peak hours of a billing period. That part of a utility service charged for on the basis of the possible demand as distinguished from the energy actually consumed.

A federal agency established in 1933 to develop the Tennessee river valley region of the southeastern U.S., and which is now nation's largest power producer.

The natural, convective movement of air or water due to differences in temperature. In solar passive design a thermosyphon collector can be constructed and attached to a house to deliver heat to the home by the continuous pattern of the convective loop (o ...

A description of how well people in a lighted space can see to do visual tasks and how visually comfortable they feel in that space.

The unit price and quantity to which it applies as specified in a rate schedule or contract.

The decomposition of organic material to alcohol, methane, etc., by organisms, such as yeast or bacteria, usually in the absence of oxygen.

The sum of all the costs both recurring and nonrecurring, related to a product, structure, system, or service during its life span or specified time period.

A construction element used for ceiling support.

The force that pulls a wind turbine blade, as opposed to drag.

A solar thermal collector that has an absorber that does not have a glazed covering. Solar swimming pool heater systems usually use unglazed collectors because they circulate relatively large volumes of water through the collector and capture nearly 80 pe ...

Standardized weights or volumes for heating fuels.

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

A profile of how the wind speed changes with height above the surface of the ground or water.

The arrangement, proportion, and design of windows in a building.

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 processes that a work input/output system undergoes and in which the initial and final states are identical.

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 ...

Fuel gas with a heating value of between 200 and 300 Btu per cubic foot.

A type of municipal solid waste (MSW) incineration facility in which MSW is burned with only minor presorting to remove oversize, hazardous, or explosive materials. Mass burn facilities can be large, with capacities of 3000 tons (2.7 million kg) of MSW pe ...