Discharging a battery to 20 percent or less of its full charge capacity.

A term used for the transparent or translucent material in a window. This material (i.e. glass, plastic films, coated glass) is used for admitting solar energy and light through windows.

A component of a hydropower plant; a pipe that delivers water to the turbine.

A combustion heating appliance that vents the combustion by-products directly into the heated space. The latest models have oxygen-sensors that shut off the unit when the oxygen level in the room falls below a safe level.

The area between the layers of glazing (panes) of a window.

A slender threadlike spike of pure crystalline material, such as silicon.

A building structural element that is built onto a building's exterior along the inner edges of all the windows, and extending from the ground to the eaves. Wingwalls help ventilate rooms that have only one exterior wall which leads to poor cross ventilat ...

The amount of power a wind turbine can produce at its rated wind speed, e.g., 100 kW at 20 mph. The rated wind speed generally corresponds to the point at which the conversion efficiency is near its maximum. Because of the variability of the wind, the amo ...

An air distribution outlet, typically located in the ceiling, which mixes conditioned air with room air.

A colorless, pungent, gas (NH3) that is extremely soluble in water, may be used as a refrigerant; a fixed nitrogen form suitable as fertilizer.

A pump for circulating the heat transfer fluid in a hydronic heating system.

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.

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

The weight of a material per unit of volume compared to the weight of the same volume of water.

That portion of supply air that is drawn from outside, plus any recirculated air that has been treated to maintain a desired air quality.

A method of preventing oxidation of the exposed metal in structures by imposing between the structure and the ground a small electrical voltage.

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

A material used to seal areas of potential air leakage into or out of a building envelope.

Energy available as a result of motion that varies directly in proportion to an object's mass and the square of its velocity.

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