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.

A refined petroleum product suitable for use as a fuel in internal combustion engines.

The measure of seasonal or annual efficiency of a heat pump operating in the heating mode. It takes into account the variations in temperature that can occur within a season and is the average number of Btu of heat delivered for every watt-hour of electri ...

A profile of how the wind speed changes with height above the surface of the ground or water.

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 point or outdoor temperature where the heating capacity of a heat pump matches the heating requirements of a building.

A material used to seal gaps around windows and exterior doors.

The decomposition of organic material to alcohol, methane, etc., by organisms, such as yeast or bacteria, usually in the absence of oxygen.

A material that can be used to store thermal energy as latent heat. Various types of materials have been and are being investigated such as inorganic salts, eutectic compounds, and parrafins, for a variety of applications, including solar energy storage ( ...

The maximum load that a device is capable of carrying.

The sum of all the costs both recurring and nonrecurring, related to a product, structure, system, or service during its life span or specified time period.

A federal agency established in 1933 to develop the Tennessee river valley region of the southeastern U.S., and which is now nation's largest power producer.

A diagram that indicates the average percentage of time that the wind blows from different directions, on a monthly or annual basis.

A battery-powered electrically driven vehicle.

The storage of heat energy during utility off-peak times at night, for use during the next day without incurring daytime peak electric rates.

A thermal storage wall is a south-facing wall that is glazed on the outside. Solar heat strikes the glazing and is absorbed into the wall, which conducts the heat into the room over time. The walls are at least 8 in thick. Generally, the thicker the wall, ...

A water heater that heats water before it is directly distributed for end use as required; a demand water heater.

The path followed by electrons from a generation source, through an electrical system, and returning to the source.

The use of devices to limit or prevent the release of pollution into the atmosphere.

A heating system, such as a solar water heater or geothermal heatpump, in which the working fluid is heated and used directly; in an open-loop solar system, the domestic water is circulated in the collector loop.