The fundamental constituent of all vegetative tissue; the most abundant material in the world.

A system where heat is supplied to areas of a building from a single appliance through a network of ducts or pipes.

A large power plant that generates power for distribution to multiple customers.

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 ...

A measure of a fuel's (liquid) ease of self-ignition.

A byproduct of low-temperature carbonization of a solid fuel.

A material formed from the incomplete combustion or destructive distillation (carbonization) of organic material in a kiln or retort, and having a high energy density, being nearly pure carbon. (If produced from coal, it is coke.) Used for cooking, the ma ...

A free and mobile conduction electron or hole in a semiconductor.

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

A method of depositing thin semiconductor films used to make certain types of solar photovoltaic devices. With this method, a substrate is exposed to one or more vaporized compounds, one or more of which contain desirable constituents. A chemical reaction ...

A device for removing heat from a gas or liquid stream for air conditioning/cooling.

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.

A family of chemicals composed primarily of carbon, hydrogen, chlorine, and fluorine whose principal applications are as refrigerants and industrial cleansers and whose principal drawback is the tendency to destroy the Earth's protective ozone layer.

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

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.

As time increases from zero at the terminals of an inductor, the voltage comes to a particular value on the sine function curve ahead of the current. The voltage reaches its negative peak exactly 90 degrees before the current reaches its negative peak thu ...

A type of furnace or reactor in which the emission of sulfur compounds is lowered by the addition of crushed limestone in the fluidized bed thus obviating the need for much of the expensive stack gas clean-up equipment. The particles are collected and rec ...

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.

The prevailing or average weather conditions of a geographic region.