The ratio of the radiant energy (heat) leaving (being emitted by) a surface to that of a black body at the same temperature and with the same area; expressed as a number between 0 and 1.

The amount of energy derived from an electrical source per unit quantity of electricity passing through the source.2. Electrical potential; voltage.

The wind speed and direction in an undisturbed flow.

The discomfort or interference with visual perception when viewing a bright object against a dark background.

A type of heating system where heat, resulting when electric current flows through an "element" or conductor, such as Nichrome, which has a high resistance, is radiated to a room.

The process of breaking down organic material; reduction of the net energy level and change in physical and chemical composition of organic material.

The wheeling of electric power in amounts and at prices that generally have been negotiated in longterm contracts between the generator and a distributor or very large consumer of power.

The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy v ...

The potential energy available in a fuel as received, taking into account the energy loss in evaporating and superheating the water in the fuel. Equal to the higher heating value minus 1050W where W is the weight of the water formed from the hydrogen in t ...

A registered trademark name for houses built with tires, aluminum cans, and earth.

Under the First Law of Thermodynamics, efficiency is the ratio of work or energy output to work or energy input, and cannot exceed 100 percent. Efficiency under the Second Law of Thermodynamics is determined by the ratio of the theoretical minimum energy ...

A term used for a wind energy conversion device that produces electricity; typically having one, two, or three blades.

A material applied to window panes that controls heat gain and loss, reduces glare, minimizes fabric fading, and provides privacy. These films are retrofitted on existing windows.

A thermal storage wall is a south-facing wall that is glazed on the outside. Solar heat strikes the glazing and is absorbed into the wall, which conducts the heat into the room over time. The walls are at least 8 in thick. Generally, the thicker the wall, ...

States that energy cannot be created or destroyed, but only changed from one form to another. First Law efficiency measures the fraction of energy supplied to a device or process that it delivers in its output. Also called the law of conservation of energ ...

The addition of dopants to a semiconductor.

Classifications of fires developed by the National Fire Protection Association.

The first law states that energy can not be created or destroyed; the second law states that when a free exchange of heat occurs between two materials, the heat always moves from the warmer to the cooler material.

A statement of the electric rate(s), terms, and conditions for electricity sale or supply.

A measure of air purity that is equal to one complete air change (in an interior space).