Vapour pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapour in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.

In a mechanical compression chiller technology, the coolant is circulated through a chilling coil heat exchanger that is inserted in the filter house, downstream from the filtering stage.

Vapor lock is a problem caused by liquid fuel changing state to gas while still in the fuel delivery system of gasoline-fueled internal combustion engines.

In physics, a vapour is a substance in the gas phase at a temperature lower than its critical temperature which means that the vapor can be condensed to a liquid by increasing the pressure on it without reducing the temperature.

A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column, creating very high electric potentials.

A value chain is a set of activities that a firm operating in a specific industry performs in order to deliver a valuable product (i.e., good and/or service) for the market.

A vacuum is space devoid of matter.

Consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft.

A utility tunnel, utility corridor, or utilidor is a passage built underground or above ground to carry utility lines such as electricity, steam, water supply pipes, and sewer pipes.

Utility sub-metering is a system that allows a landlord, property management firm, condominium association, homeowners association, or other multi-tenant property to bill tenants for individual measured utility usage.

A post or column that supports overhead power lines and associated equipment such as transformers.

The utility frequency, line frequency or mains frequency is the nominal frequency of the oscillations of alternating current in a wide area synchronous grid transmitted from a power station to the end-user.

Resources that are provided to homes and industry such as electricity, water and natural gas.

An urban heat island (UHI) is an urban area or metropolitan area that is significantly warmer than its surrounding rural areas due to human activities.

Uranium-238 is the most common isotope of uranium found in nature, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor.

Uranium-233 was investigated for use in nuclear weapons and as a reactor fuel. It has been used successfully in experimental nuclear reactors and has been proposed for much wider use as a nuclear fuel.

Uranium trioxide is used industrially in the reprocessing of nuclear fuel and uranium enrichment.

Uranium ore deposits are economically recoverable concentrations of uranium within the Earth's crust.

Uranium mining is the process of extraction of uranium ore from the ground.

Uranium hexafluoride colloquially known as "hex" in the nuclear industry, is a compound used in the process of enriching uranium, which produces fuel for nuclear reactors and nuclear weapons.