A slightly sloped roof, usually with a tar and gravel cover. Most commercial buildings use this kind of roof.

A lamp that consists of a sealed arc tube inside a glass envelope, or outer jacket. The inner arc tube is filled with elements that emit light when ionized by electric current. A ballast is required to provide the proper starting voltage and to regulate c ...

The quantity of heat required to change the temperature of one unit weight of a material by one degree.

A device that removes airborne particles from breathable air. Negative ions are produced and give up their negative charge to the particles. These new negative particles are then attracted to the positive particles surrounding them. This accumulation proc ...

One millionth of a meter (10-6 m).

The process of modifying a building's structure.

A toilet that uses less water than a standard one during flushing, for the purpose of conserving water resources.

The process of degrading organic material (biomass) by microorganisms in aerobic conditions.

The process by which water in air changes from a vapor to a liquid due to a change in temperature or pressure; occurs when water vapor reaches its dew point (condensation point); also used to express the existence of liquid water on a surface.

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

A type of heating appliance that performs more than one function, for example space and water heating.

The demand on an energy producing system; the energy consumption or requirement of a piece or group of equipment.

A high-intensity discharge lamp type that uses mercury and several halide additives as light-producing elements. These lights have the best Color Rendition Index (CRI) of the High-Intensity Discharge lamps. They can be used for commercial interior lightin ...

The physical material upon which a photovoltaic cell is applied.

A device that that converts direct current electricity (from for example a solar photovoltaic module or array) to alternating current for use directly to operate appliances or to supply power to a electricity grid.

The loss in static pressure of a fluid (liquid or gas) in a system due to friction from obstructions in pipes, from valves, fittings, regulators, burners, etc, or by a breech or rupture of the system. Pressurization Testing

A closed-loop solar heating system in which the heat transfer fluid in the collector loop drains into a tank or reservoir whenever the booster pump stops to protect the collector loop from freezing.

Legislation authorizing a U.S. biomass and alcohol fuel program, and that authorized loan guarantees and price guarantees and purchase agreements for alcohol fuel production.

Fuels formed in the ground from the remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas, and coal are fossil fuels.

Any material that can be burned to make energy.