A method of financial and economic analysis used to determine present and future values of investments or expenses.

A water and energy conserving device that limits the amount of water that a faucet or showerhead can deliver.

The period marked by successive crossing of the earth's meridian by the sun; the hour angle of the sun at a point of observance (apparent time) is corrected to true (solar) time by taking into account the variation in the earth's orbit and rate of rotatio ...

A value used to estimate interior air cooling requirements (load) calculated as the number of degrees per day (over a specified period) that the daily average temperature is above 65 degrees Fahrenheit (or some other, specified base temperature). The dail ...

A solar heating system that uses a liquid as the heat transfer fluid.

One layer of glass in a window frame. It has very little insulating value (R-1) and provides only a thin barrier to the outside and can account for considerable heat loss and gain.

The amount of heat required to raise a unit mass of a substance through one degree, expressed as a ratio of the amount of heat required to raise an equal mass of water through the same range.

A steady-state fermentation process.

A type of water heater in which heated water is stored within the tank. Hot water is released from the top of the tank when a hot water faucet is turned. This water is replaced with cold water that flows into the tank and down to just above the bottom pla ...

A window located on the roof of a structure to provide interior building spaces with natural daylight, warmth, and ventilation.

The mean distance a free electron or hole moves before recombining with another hole or electron.

A deposition process whereby heat is used to break molecules into elemental sources that are then spray deposited on a substrate.

A plot of a wind energy conversion device's power output versus wind speed.

The fossil fuels: coal, oil, and natural gas.

The apparent angle of the sun north or south of the eath's equatorial plane. The earth's rotation on its axis causes a daily change in the declination.

The difference between the brightness of an object compared to that of its immediate background.

Energy that is capable or available for doing work; the time rate at which work is performed, measured in horsepower, Watts, or Btu per hour. Electric power is the product of electric current and electromotive force.

A type of structural, insulated product with foam insulation contained between two facings of drywall, or structural wood composition boards such as plywood, waferboard, and oriented strand board.

The total capacity of electrical generation devices in a power station or system.

A technique for insulating and sealing exterior walls that reduces vapor diffusion through air leakage points by installing pre-cut blocks of rigid foam insulation over floor joists, sheet subfloor, and top plates before drywall is installed.