Air that is returned from a heated or cooled space, reconditioned and/or cleaned, and returned to the space.

The supportive structure of a building.

A horizontal axis wind turbine in which the rotor is downwind of the tower.

Parasitic resistance to current flow in a cell due to mechanisms such as resistance from the bulk of the semiconductor material, metallic contacts, and interconnections.

A ratio of the work or useful energy output of a system versus the amount of work or energy inputted into the system as determined by using the same energy equivalents for energy in and out. Is used as a measure of the steady state performance or energy e ...

Costs that are repetitive and occur when an organization produces similar goods or services on a continuing basis.

A window glass that has been coated with a reflective film and is useful in controlling solar heat gain during the summer.

A device for converting the flow of a fluid (air, steam, water, or hot gases) into mechanical motion.

A device used to remove particulate matter from the waste gasses of a combustion power plant.

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

A heat engine of the reciprocating (piston) where the working gas and a heat source are independent. The working gas is compressed in one region of the engine and transferred to another region where it is expanded. The expanded gas is then returned to the ...

Electrical energy lost due to inherent inefficiencies in an electrical transmission and distribution system under specific conditions.

The shape of the phase power at a certain frequency and amplitude.

A mechanism used by electric utilities to determine prices for electricity; typically defines rates according to amounts of power demanded/consumed during specific time periods.

A chemical compound produced in a reaction between ethanol and isobutylene (a petroleum-derived by-product of the refining process). ETBE has characteristics superior to other ethers: low volatility, low water solubility, high octane value, and a large re ...

The power available from the rise and fall of ocean tides. A tidal power plant works on the principal of a dam or barrage that captures water in a basin at the peak of a tidal flow, then directs the water through a hydroelectric turbine as the tide ebbs.

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

The inherent characteristic of a material to inhibit the transfer of energy. In electrical conductors, electrical resistance results in the generation of heat. Electrical resistance is measured in Ohms. The heat transfer resistance properties of insulatio ...

A tank used in a closed-loop solar heating system that provides space for the expansion of the heat transfer fluid in the pressurized collector loop.

This represents three layers of glazing in a window with an airspace between the middle glass and the exterior and interior panes.