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Glossary of Energy Terms "V"

VAV System (Variable Air Volume System): A mechanical Heating Ventilating and Air Conditioning system capable of serving multiple zones which controls the temperature maintained in a zone by controlling the amount of heated or cooled air supplied to the zone.

Vapor Barrier: A material with a permeance of one perm or less which provides resistance to the transmission of water vapor.

Vapor Liquid (V/L) Ratio: The V/L ratio is a measure of the tendency of a fuel to vapor lock.

Vapor Lock: A condition caused when fuel fails to flow to an engine due to increased fuel vapor pressure in the inlet fuel line or internal fuel pump cavities. The increased fuel vapor pressure is caused by high temperatures or heat build-up.

Ventilation: The process of supplying or removing air by natural or mechanical means to or from any space. Such air may or may not have been conditioned or treated.

Verification Phase: The step of the Nebraska Energy Emergency Plan to determine the existence and scope of an energy shortage and report to the Governor and other policymakers as appropriate.

Vertical Integration: An arrangement whereby the same company owns all the different aspects of making, selling and delivering a product or service. In the electric industry, it refers to the historically common arrangement whereby a utility would own its own generating plants, transmission system and distribution lines to provide all aspects of electric service.

Vessel Bunkering: Includes sales for the fueling of commercial or private boats, inclusive to oil company vessels but excluding military vessels.

Visible Light Transmittance: The ratio of visible light transmitted through a substance to the total visible light incident on its surface.

Volt (V): A unit of electromotive force. It is the amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and office have 120 volts.

Voltage Of A Circuit (Electric Utility): The electric pressure of a circuit, measured in volts. Usually a nominal rating, based on the maximum normal effective difference of potential between any two conductors of the circuit.

Volumetric Wires Charge: A type of charge for using the transmission and/or distribution system that is based on the volume of electricity that is transmitted.