The replacement of a non-functional or ineffective lamp with a new, more efficient lamp.

A device used to measure total incident solar radiation (direct beam, diffuse, and reflected radiation) per unit time per unit area.

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

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

The electrical power that oscillates between the magnetic field of an inductor and the electrical field of a capacitor. Reactive power is never converted to non-electrical power. Calculated as the square root of the difference between the square of the ki ...

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 ...

Those privately or publicly owned establishments that generate, transmit, distribute, or sell electricity.

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

These lights use an electrically heated filament to produce light in a vacuum or inert gas-filled bulb.

A measure of the effective cooling capacity of a refrigerator, expressed in Btu per hour or in tons, where one (1) ton of capacity is equal to the heat required to melt 2,000 pounds of ice in 24 hours or 12,000 Btu per hour.

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

Materials with various qualities that are applied to glass windows before installation. These coatings reduce radiant heat transfer through the window and also reflects outside heat and a portion of the incoming solar energy, thus reducing heat gain. The ...

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 ...

A gas that does not react with other substances; e.g. argon or krypton; sealed between two sheets of glazing to decrease the U-value (increase the R-Value) of windows.

A way of joining photovoltaic cells or modules by connecting positive leads together and negative leads together; such a configuration increases the current, but not the voltage.

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 ...

The thermal energy used in an industrial process.

The process of implementing measures to reduce peak power demands on a system.

The fine liquid or solid particles contained in combustion gases. The quantity and size of particulates emitted by cars, power and industrial plants, wood stoves, etc are regulated by the U.S. Environmental Protection Agency.

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.