A device used to protect the user of any electrical system or appliance from shock.

A type of solar thermal collector where the heat transfer fluid flows through tubes formed in the absorber plate.

A masonry or metal stack that creates a draft to bring air to a fire and to carry the gaseous byproducts of combustion safely away.

The ratio of the coincident, maximum demand or two or more loads to the sum of their noncoincident maximum demand for a given period; the reciprocal of the diversity factor, and is always less than or equal to one.

The ratio of solar radiation captured and transfered to the collector (heat transfer) fluid.

The physical measure of the subjective sensation of brightness; measured in lumens.

A device built into or installed above a combustion appliance to assure the escape of combustion byproducts, to prevent backdrafting of the appliance, or to neutralize the effects of the stack action of the chimney or vent on the operation of the applianc ...

This is another name for an induction motor. The motors consist of a rotor inside a stator. The rotor has laminated, thin flat steel discs, stacked with channels along the length. If the casting composed of bars and attached end rings were viewed without ...

A condition that can occur in a solar collector if the working fluid does not circulate when sun is shining on the collector.

The central heating or cooling system contains a fan that gets its air supply through these ducts, which ideally should be installed in every room of the house. The air from a room will move towards the lower pressure of the return duct.

An estimate of power demand at some future period.

The force per unit area acting on the surface of a solid boundary parallel to the flow.

The two times of the year when the sun crosses the equator and night and day are of equal length; usually occurs on March 21st (spring equinox) and September 23 (fall equinox).

The inner coil in a heat pump that, during the cooling mode, absorbs heat from the inside air and boils the liquid refrigerant to a vapor, which cools the house.

The process of sending or moving electricity from one point to another; usually defines that part of an electric utility's electric power lines from the power plant buss to the last transformer before the customer's connection.

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 heating appliance that extracts so much of the available heat content from a combusted fuel that the moisture in the combustion gases condenses before it leaves the furnace. Also this furnace circulates a liquid to cool the furnace's heat exchan ...

The U.S. Government's 12-month financial year, from October to September, of the following calender year; e.g.: FY 1998 extends from Oct. 1, 1997 to Sept. 30, 1988.

The trapping of light by refraction and reflection at critical angles inside a semiconductor device so that it cannot escape the device and must be eventually absorbed by the semiconductor.

A container that holds rock used as the thermal mass to store solar energy in a solar heating system.