A material or structural element that inhibits air flow into and out of a building's envelope or shell. This is a continuous sheet composed of polyethylene, polypropylene, or extruded polystyrene. The sheet is wrapped around the outside of a house during ...

The total cost of production divided by the total quantity produced.

The use of direct, diffuse, or reflected sunlight to provide supplemental lighting for building interiors.

Consist of three main layers. The top layer is near ambient and has low salt content. The bottom layer is hot, typically 160 F to 212 F (71 C to 100 C), and is very salty. The important gradient zone separates these zones. The gradient zone acts as a tran ...

An insulation product composed of loose fibers or fiber pellets that are blown into building cavities or attics using special pneumatic equipment.

The maximum load that a motor is capable of supplying.

The negative pole or electrode of an electrolytic cell, vacuum tube, etc., where electrons enter (current leaves) the system; the opposite of an anode.

A device that cuts off the flow of hot or cold air to or from a room as controlled by a thermostat.

Biomass converted directly to energy or converted to liquid or gaseous fuels such as ethanol, methanol, methane, and hydrogen.

The control of the quality, quantity, and temperature-humidity of the air in an interior space.

A measure of the heating requirements of a building expressed in Btu per degree-day.

The purpose for which useful energy or work is consumed.

A condition that results from an imbalance between the number of protons and the number of electrons in a substance.

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

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 ...

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

A unit of power equal to 1 billion Watts; 1 million kilowatts, or 1,000 Megawatts.

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 ...

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

Energy systems supply individual, or small-groups, of energy loads.