A measure of the number of cycles or wavelengths of electrical energy per second; U.S. electricity supply has a standard frequency of 60 hertz.

This compound of nitrogen and oxygen is formed by the oxidation of nitric oxide (NO) which is produced by the combustion of solid fuels.

An idealized process in which a working fluid (water, air, ammonia, etc) successively changes its state (from a liquid to a gas and back to a liquid) for the purpose of producing useful work or energy, or transferring energy.

The addition of dopants to a semiconductor.

The process by which materials expel or release gasses.

A valve used to mix heated water with cold in a heating system to provide a desired water temperature for end use.

A measure of the amount of light incident on a surface; measured in foot-candles or Lux.

A hydropower plant that is operated at maximum allowable capacity for part of the day and is either shut down for the remainder of the time or operated at minimal capacity level.

The heat that flows from the building interior, through the building envelope to the outside environment.

A type of water heater that circulates water through a heat exchanger in a boiler. The heated water then flows into an insulated storage tank.

The amount of heat produced from the complete combustion of a unit of fuel. The higher (or gross) heating value is that when all products of combustion are cooled to the pre-combustion temperature, water vapor formed during combustion is condensed, and ne ...

A seal used to prevent the leakage of fluids, and also maintain the pressure in an enclosure.

All the components of the appliance used to condition interior air of a building.

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

A generic term for an electrical conductor.

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 space heating device that burns pellets; are more efficient, clean burning, and easier to operate relative to conventional cord wood burning appliances.

A wood or gas burning appliance that is primarily used to provide ambiance to a room. Conventional, masonry fireplaces without energy saving features, often take more heat from a space than they put into it.

These are state government agencies responsible for the regulation of public utilities within a state or region. A state legislature oversees the PUC by reviewing changes to utility laws, rules and regulations and approving the PUC's budget. The commissio ...

Energy output from a system that equals energy input.