An apparatus for converting the energy available in the wind to mechanical energy that can be used to power machinery (grain mills, water pumps) and to operate an electrical generator.

A large number of thermocouples connected in series.

The relationship of a building to true south, as specified by the direction of its longest axis.

A unit of heat containing 100,000 British thermal units (Btu).

A type of heat pump that transfers heat from outdoor air to indoor air during the heating season, and works in reverse during the cooling season.

An abbreviation for one thousand cubic feet of natural gas with a heat content of 1,000,000 Btus, or 10 therms.

A mound of dirt next to exterior walls to provide wind protection and insulation.

The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy v ...

The housing around a motor that supports the active parts and protects them. They come in different varieties (open, protected) depending on the degree of protection required.

A heat absorbing reaction or a reaction that requires heat.

The cutting of a grid pattern of grooves in a semiconductor material, generally for the purpose of making interconnections.

Ratio of useful energy output of a device to the energy input, averaged over an entire heating season.

A type of heat pump that uses sealed horizontal or vertical pipes, buried in the ground, as heat exchangers through which a fluid is circulated to transfer heat.

A device that measures the intensity of direct beam solar radiation.

Any light source designed specifically to direct light a task or work performed by a person or machine.

As defined in the Energy Security Act (P.L. 96-294; 1980) as "any organic matter, including sewage, sewage sludge, and industrial or commercial waste, and mixtures of such matter and inorganic refuse from any publicly or privately operated municipal waste ...

The maximum possible voltage across a photovoltaic cell; the voltage across the cell in sunlight when no current is flowing.

see Peak Power

Generation of energy at the location where all or most of it will be used.

A non-crystalline semiconductor material that has no long-range order.