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

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 construction element that inhibits termites from entering building foundations and walls.

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

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

A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel times 100 (for percent).

The energy developed through the use of heat energy.

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

An architectural design (also known as the double envelope house), sometimes called a "house-within-a-house," that employs a double envelope with a continuous airspace of at least 6 to 12 inches on the north wall, south wall, roof, and floor, achieved by ...

This designates the resistance of a material to heat conduction. The greater the R-value the larger the number.

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 device consisting of two dissimilar conductors with their ends connected together. When the two junctions are at different temperatures, a small voltage is generated.

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 study of the transformation of energy from one form to another, and its practical application. (see Law(s) of Thermodynamics above).

The conversion of heat into electricity by the use of thermocouples.

A building energy auditing technique for locating areas of low insulation in a building envelope by means of a thermographic scanner.

A device where sunlight concentrated onto a absorber heats it to a high temperature, and the thermal radiation emitted by the absorber is used as the energy source for a photovoltaic cell that is designed to maximize conversion efficiency at the wavelengt ...

A large number of thermocouples connected in series.

A device used to control temperatures; used to control the operation of heating and cooling devices by turning the device on or off when a specified temperature is reached.

The natural, convective movement of air or water due to differences in temperature. In solar passive design a thermosyphon collector can be constructed and attached to a house to deliver heat to the home by the continuous pattern of the convective loop (o ...