A power plant that produces electricity by the force of water falling through a hydro turbine that spins a generator.

The lowest wind speed at which a wind turbine begins producing useable power.

The push or pull that alters the motion of a moving body or moves a stationairy body; the unit of force is the dyne or poundal; force is equal to mass time velocity divided by time.

A current carrier, either an electron or a hole, that is in the minority in a specific layer of a semiconductor material; the diffusion of minority carriers under the action of the cell junction voltage is the current in a photovoltaic device.

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

Sunlight scattered by atmospheric particles and gases so that it arrives at the earth's surface from all directions and can not be focused.

The physical process by which a liquid or solid is transformed into the gaseous state. For this process a mechanical device uses the outside air's heat to evaporate water that is held by pads inside the cooler. The heat is drawn out of the air through thi ...

A device used to regulate motor speed, or, in a wind energy conversion system, to control the rotational speed of the rotor.

A building heating, ventilation, and/or air conditioning system that distributes conditioned air to individual zones or rooms.

One pound of water in vapor phase; is NOT steam pressure, which is expressed as pounds per square inch (psi).

The process of removing moisture; involves evaporation.

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 ...

Pounds/force per square inch gauge.

In reference to solar thermal collectors, the condition where the heat transfer fluid is flowing through the collector loop under normal operating conditions.

The fluid, liquid (water or water/antifreeze solution) or air, used to absorb solar energy and transfer it for direct use, indirect heating of interior air or domestic water, and/or to a heat storage medium.

An energy band in a semiconductor in which electrons can move freely in a solid, producing a net transport of charge.

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

Metal, usually galvanized sheet metal, used to provide protection against infiltration of precipitation into a roof or exterior wall; usually placed around roof penetrations such as chimneys.

A term for the process of transmitting electricity over transmission lines not owned by the supplier of the electricity to a retail customer of the supplier. With retail wheeling, an electricity consumer can secure their own supply of electricity from a b ...

A type of heating system that provides heat from the resistance of an electrical current flowing through a conductor.