District heating in the context of "Energy system"

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. Communications utilities like fiber optics, cable television, and telephone cables are also sometimes carried. One may also be referred to as a services tunnel, services trench, services vault, or cable vault. Smaller cable containment is often referred to as a cable duct or underground conduit. Direct-buried cable (installed using trenches) is a major alternative to ducts or tunnels.

A nuclear reactor is a device used to sustain a controlled fission nuclear chain reaction. They are used for commercial electricity, marine propulsion, weapons production and research. Fissile nuclei (primarily uranium-235 or plutonium-239) absorb single neutrons and split, releasing energy and multiple neutrons, which can induce further fission. Reactors stabilize this, regulating neutron absorbers and moderators in the core. Fuel efficiency is exceptionally high; low-enriched uranium is 120,000 times more energy-dense than coal.

Heat from nuclear fission is passed to a working fluid coolant. In commercial reactors, this drives turbines and electrical generator shafts. Some reactors are used for district heating, and isotope production for medical and industrial use.

Water heating is a heat transfer process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated to steam have many uses.

Domestically, water is traditionally heated in vessels known as water heaters, kettles, cauldrons, pots, or coppers. These metal vessels that heat a batch of water do not produce a continual supply of heated water at a preset temperature. Rarely, hot water occurs naturally, usually from natural hot springs. The temperature varies with the consumption rate, becoming cooler as flow increases.

A pipeline bridge is a bridge for running a pipeline over a river or another obstacle. Pipeline bridges for liquids and gases are, as a rule, only built when it is not possible to run the pipeline on a conventional bridge or under the river. However, as it is more common to run pipelines for centralized heating systems overhead, for this application even small pipeline bridges are common.

Pipeline bridges may be made of steel, fiber reinforced polymer, reinforced concrete or similar materials. They may vary in size and style depending on the size of the pipeline being run. As there is normally a steady flow in pipelines, they can be designed as suspension bridges. They may also be added to an existing bridge. A pipeline bridge may be equipped with a walkway for maintenance purposes, but for safety and security reasons, the walkway is usually not open to the public.

A manhole (utility hole, maintenance hole, or sewer hole) is an opening to a confined space such as a shaft, utility vault, or large vessel. Manholes, typically protected by a manhole cover, are often used as an access point for an underground public utility, allowing inspection, maintenance, and system upgrades. The majority of underground services have manholes, including water, sewers, telephone, electricity, storm drains, district heating, and gas.

Manholes are generally found in urban areas, in streets and occasionally under sidewalks. In rural and undeveloped areas, services such as telephone and electricity are usually carried on utility poles or even pylons rather than underground.

A public utility building (also known as infrastructure building, and utility building) is a building used by a public utility to maintain its office or to house equipment used in connection to the public utility. Examples include pumping stations, gas regulation stations, and other buildings that house infrastructure components and equipment of water purification systems, water distribution networks, sewage treatment systems, electric power distribution, district heating, telephone exchanges, and public service telecommunication equipment.