For a wind turbine, the ratio of the speed of the tip of a turbine blade for which the power coefficient is at maximum.

The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same.

A wall with high thermal mass used to store solar energy passively in a solar home. The wall absorbs solar energy and transfers it to the space behind the wall by means of radiation and by convection currents moving through spaces under, in front of, and ...

An architectural design invented by Buckminster Fuller with a regular polygonal structure based on radial symmetry.

A water heater that uses electricity to move heat from one place to another instead of generating heat directly.

A type of passive solar heating system where heat is collected in one area for use in another.

A clear, colorless, very mobile liquid that is flammable and poisonous; used as a fuel and fuel additive, and to produce chemicals.

One horsepower provided over one hour; equal to 0.745 kilowatt-hour or 2,545 Btu.

A device for measuring light intensity that works by converting light falling on, or reach it, to electricity, and then measuring the current; used in photometers.

A unit of air cooling capacity; 12,000 Btu per hour.

The load-carrying ability of an electric power plant during a specific time interval and period when related to the characteristics of the load to be/being supplied; determined by capability, operating power factor, and the portion of the load the station ...

An architectural feature used to shade exterior walls; usually made of a lattice of metal or wood; often covered by vines to provide additional summertime shading.

The length of time that a product or appliance is expected to meet a certain level of performance under nominal operating conditions; in a luminaire, the period after which the lumen depreciation and lamp failure is at 70% of its initial value.

A registered trademark for a cholorflourocarbon (CFC) gas that is highly stable and that has been historically used as a refrigerant.

A device used to interrupt or break an electrical circuit when an overload condition exists; usually installed in the positive circuit; used to protect electrical equipment.

Also known as "power towers," these use fields of two-axis tracking mirrors known as heliostats. Each heliostat is individually positioned by a computer control system to reflect the sun's rays to a tower-mounted thermal receiver. The effect of many helio ...

In reference to a wind energy conversion device, the area through which the rotor blades spin, as seen when directly facing the center of the rotor blades.

The structural materials and elements used to construct a wall.

A measure of window glazing performance that is the ratio of the total solar heat gain through a specific window to the total solar heat gain through a single sheet of double-strength glass under the same set of conditions; expressed as a number between 0 ...

The voltage developed across a cell by the current flow through the resistance of the cell.