A measure of the average amount of a specified pollutant or material emitted for a specific type of fuel or process.

Thermosyphon systems use a separate storage tank located above the collector. Liquid warmed in the collector rises naturally above the collector, where it is kept until it is needed. The liquid can be either water or a glycol solution. If the fluid is wat ...

A solar water or space-heating system in which solar energy is collected, and/or moved by natural convection without using pumps or fans. Passive systems are typically integral collector/storage (ICS; or batch collectors) or thermosyphon systems. The majo ...

The amount of time required for positive cash flows to equal the total investment costs.

A device that produces mechanical energy directly from two heat reservoirs of different temperatures. A machine that converts thermal energy to mechanical energy, such as a steam engine or turbine.

The products of all combustion processes formed by the combination of nitrogen and oxygen.

The process of using heat that is rejected in one part of a cycle for another function or in another part of the cycle.

The process of producing electricity by transforming other forms or sources of energy into electrical energy; measured in kilowatt-hours.

An electricity generating facility that uses geothermal energy.

The total amount of electric energy loss in an electric system between the generation source and points of delivery.

The maximum value of natural solar insolation.

A lamp where the light beam is focused 2 inches ahead of the lamp reducing the amount of light trapped in the fixture.

Material such as brick, rock, or stone.

The ability to send or wheel electric power to a customer over a transmission and distribution system that is not owned by the generator (seller) of the power.

An aluminum foil fabricated insulator with backings applied to provide a series of closed air spaces with highly reflective surfaces.

The value of a personal portfolio, product, or investment after depreciation and interest on debt capital are subtracted from operating income. It can also be thought of as the equivalent worth of all cash flows relative to a base point called the present ...

Power generated by a utility unit that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.

The change in direction of a ray of light when it passes through one media to another with differing optical densities.

A solar energy concentrating technology that uses a linear receiver that tracks the focal area of a reflector or array of reflectors.

Solar collector thermal performance ratings based on collector efficiencies, usually expressed in Btu per hour for solar collectors under standard test or operating conditions for solar radiation intensity, inlet working fluid temperatures, and ambient te ...