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 ...

The structural materials and elements used to construct a wall.

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

The sum of the sensible and latent heat in a substance or fluid above a base point, usually 32 degrees Fahrenheit.

A popular term used for a length of wood or steel used in or for wall framing.

The energy liberated in a chemical reaction, as in the combustion of fuels.

Defects, such as dangling bonds, induced in an amorphous silicon semiconductor upon initial exposure to light.

A process for making inexpensive Galium Arsenide (GaAs)photovoltaic cells in which a thin film of GaAs is grown atop a thick, single-crystal GaAs (or other suitable material) substrate and then is cleaved from the substrate and incorporated into a cell, a ...

A window located high in a wall near the eaves that allows daylight into a building interior, and may be used for ventilation and solar heat gain.

A type of insulation made from virgin basalt, an igneous rock, and spun into loose fill or a batt. It is fire resistant and helps with soundproofing.

The smallest self-contained, environmentally protected structure housing interconnected photovoltaic cells and providing a single dc electrical output; also called a panel.

An electric motor rated at less than one horse power (hp).

A device used to compress air for mechanical or electrical power production, and in air conditioners, heat pumps, and refrigerators to pressurize the refrigerant and enabling it to flow through the system.

The measure of the instantaneous energy efficiency of room air conditioners; the cooling capacity in Btu/hr divided by the watts of power consumed at a specific outdoor temperature (usually 95 degrees Fahrenheit).

A liquid byproduct of wood combustion (or distillation) that condenses on the internal surfaces of vents and chimneys, which if not removed regularly, can corrode the surfaces and fuel a chimney fire.

A device, or system of devices, that allows electrical current to flow through it and allows voltage to occur across positive and negative terminals.

Air with a weight of 0.075 pounds per cubic foot with an equivalent density of dry air at a temperature of 86 degrees Fahrenheit and standard barometric pressure of 29.92 inches of mercury.

A solar energy array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array point ...

A region of electrical contact between two different materials.