A heat exchanger in which two fluids flow in opposite directions for transfer heat energy from one to the other.

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 popular term for energy produced from renewable energy resources.

A solar heating system that uses a liquid as the heat transfer fluid.

The process by which sunlight directly enters a building through the windows and is absorbed and stored in massive floors or walls.

Salt mixtures with potential applications as solar thermal energy storage materials.

The interior area of a building, calculated in square feet or meters.

A solar photovoltaic device with a specified area.

A measure of the unavailable or unusable energy in a system; energy that cannot be converted to another form.

A coating applied to the surface of the glazing of a window to reduce heat transfer through the window.

Freshly cut, unseasoned, wood.

The process of controlling indoor moisture levels and condensation.

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

The fine particulate matter entrained in the flue gases of a combustion power plant.

The lower or net heat of combustion for a fuel that assumes that all products of combustion are in a gaseous state. (See Net Heating Value below.)

see Solar Spectrum above.

The apparent angle of the sun north or south of the eath's equatorial plane. The earth's rotation on its axis causes a daily change in the declination.

The space between a hanging ceiling and the floor above or roof; usually contains HVAC ducts, electrical wiring, fire suppression system piping, etc.

The potentially useful byproducts of ethanol fermentation process.

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