A heat source, such as a space heater, used to provide more heat than that provided by a primary heating source.

The outer casing of a window that sits in a designated opening of a structure and holds the window panes in place.

The storage of compressed air in a container for use to operate a prime mover for electricity generation.

The quantity of heat required to change the temperature of one unit weight of a material by one degree.

A solid-state electrical device that converts light directly into direct current electricity of voltage-current characteristics that are a function of the characteristics of the light source and the materials in and design of the device. Solar photovoltai ...

A system where heat is supplied to areas of a building from a single appliance through a network of ducts or pipes.

A common utility monetary measure equal to one-thousandth of a dollar or a tenth of a cent.

A tubular material used to encase and protect one or more electrical conductors.

A photovoltaic device where incident sunlight is split into different spectral regions, with an optical apparatus, that are directed to individual photovoltaic cells that are optimized for converting that spectrum to electricity.

A complete PV power system composed of the module (or arrary), and balance-of-system (BOS) components including the array supports, electrical conductors/wiring, fuses, safety disconnects, and grounds, charge controllers, inverters, battery storage, etc.

A measure of the efficacy (efficiency) of lamps. It indicates the amount of light (lumens) emitted by the lamp for each unit of electrical power (Watts) used.

A type of anaerobic digester that has a mechanical mixing system and where temperature and volume are controlled to maximize the anaerobic digestion process for biological waste treatment, methane production, and odor control.

The flow rate in these systems is 1/8 to 1/5 the rate of most solar water heating systems. The low-flow systems take advantage of stratification in the storage tank and theoretically allows for the use of smaller diameter piping to and from the collector ...

A light control device that allows light levels to be manually adjusted. A dimmer can save energy by reducing the amount of power delivered to the light while consuming very little themselves.

All the natural and living things around us. The earth, air, weather, plants, and animals all make up our environment.

A mixture of substances that has a melting point lower than that of any mixture of the same substances in other proportions.

Electric power plant or utility capacity on line and running at low power in excess of actual load.

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

A smokestack or flue for exhausting the products of combustion from a combustion appliance.

An electrically charged atom or group of atoms that has lost or gained electrons; a loss makes the resulting particle positively charged; a gain makes the particle negatively charged.