A mathematical representation of the frequency or ratio that specific wind speeds occur within a specified time interval.

The space within a building or structure that is normally occupied by people, and that may be conditioned (heated, cooled and/or ventilated).

A type of water heater that has no storage tank thus eliminating storage tank standby losses. Cold water travels through a pipe into the unit, and either a gas burner or an electric element heats the water only when needed.

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.

A generic term for an electrical conductor.

The process by which materials expel or release gasses.

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

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

Energy produced by the conversion of biomass directly to heat or to a liquid or gas that can be converted to energy.

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.

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 addition of dopants to a semiconductor.

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

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

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 ...

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

In reference to a wind energy conversion system, the area of a turbine blade surface that first comes into contact with the wind.

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.

A type of heating appliance similar to a fireplace, but much more efficient and clean burning. They are made of masonry and have long channels through which combustion gases give up their heat to the heavy mass of the stove, which releases the heat slowly ...