The unoccupied, and usually unfinished and unconditioned space between the floor, foundation walls, and the slab or ground of a building.

A method of financial and economic analysis used to determine present and future values of investments or expenses.

A solid that contains pores; normally, it refers to interconnected pores that can transmit the flow of fluids. (The term refers to the aquifer geology when discussing sites for CAES.)

In reference to a wind energy conversion system, the wind speed profile in which wind speeds increase with the logarithmic of the height of the wind turbine above the ground.

Usually refers to ethanol to 160 to 200 proof.

A source of power (electricity) that can displace power from another source so that source's power can be transmitted to more distant loads.

A steady-state fermentation process.

Steam available directly from a boiler under full pressure.

see Solar Spectrum above.

The ratio of the sum of the noncoincidental maximum demands of two or more loads to their coincidental maximum demands for the same period.

A process used to apply photovoltaic semi-conductor material to a substrate by a physical vapor deposition process where high-energy ions are used to bombard elemental sources of semiconductor material, which eject vapors of atoms that are then deposited ...

The deferment of certain loads to limit electrical power demand, or the production of energy during off-peak periods for storage and use during peak demand periods.

A layer of semiconductor material (as used in a solar photovoltaic device) whose properties are essentially those of the pure, undoped, material.

The height above the ground that a horizontal axis wind turbine's hub is located.

The weight of water vapor, per unit weight of dry air.

Water in vapor form; used as the working fluid in steam turbines and heating systems.

The value or purchasing power of a dollar in a specified year carried forward or backward.

The amount of energy produced as a percentage of the amount of energy consumed.

A type of combustion heating system in which combustion air is drawn directly from outside and the products of combustion are vented directly outside. These features are beneficial in tight, energy-efficient homes because they will not depressurize a home ...

An automatic valve that is opened or closed by an electromagnet.