A compound used to make certain types of solar photovoltaic cells.

A popular term for "non-conventional" transportation fuels derived from natural gas (propane, compressed natural gas, methanol, etc.) or biomass materials (ethanol, methanol).

The conversion of the complex carbohydrates in organic material into energy.

The downward facing structural element that is directly opposite the floor.

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

A method for making sheets of polycrystalline silicon in which silicon dendrites are slowly withdrawn from a melt of silicon whereupon a web of silicon forms between the dendrites and solidifies as it rises from the melt and cools.

A tube in which combustion gases from a combustion appliance are vented out of the appliance to the outdoors.

A heat storage system that uses a heat storage medium, and where the additional or removal of heat results in a change in temperature.

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

A unit of apparent power, equal to 1,000 volt-amperes; the mathematical product of the volts and amperes in an electrical circuit.

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

A facility or piece of equipment that produces electricity.

A means to increase the thermal efficiency of a steam electric generating system by converting some waste heat from the condenser into electricity. The heat engine in a bottoming cycle would be a condensing turbine similar in principle to a steam turbine ...

A type of (geothermal) heat pump that uses well (ground) or surface water as a heat source. Water has a more stable seasonal temperature than air thus making for a more efficient heat source.

The production of an electric current in a conductor by the variation of a magnetic field in its vicinity.

The unit of illuminance equivalent to 1lumen per square meter.

A measure of the electrical resistance of a material equal to the resistance of a circuit in which the potential difference of 1 volt produces a current of 1 ampere.

The pressure of the steam or water in a boiler as measured; usually expressed in pounds per square inch gauge (psig).

The ratio of a photovoltaic cell's actual power to its power if both current and voltage were at their maxima. A key characteristic in evaluating cell performance.

The amount of work accomplished by electrical power, usually measured in kilowatt-hours (kWh). One kWh is 1,000 Watts and is equal to 3,413 Btu.2.The energy of moving electrons.