District heating and cooling networks

Insulated pipes carrying hot water, steam or chilled water across a town or industrial park.

Transport · Heat, motion and embodied energy · No. 64

• Transport
• Form: Heat

Europe's 17,000 heat networks pump hot water through nearly 190,000 km of pipe to about 70 million people.

Chart: Illustration: District heating and cooling networks

Where it comes from

Chart: Map of where it comes from

Central plants make heat with boilers, waste heat from power stations or large heat pumps, then pump hot water through buried, foam-insulated steel pipes to every building.

Three things to know

1. Running the same pipes at 55/25 C instead of 80/45 C would cut heat loss by about 43%.
2. Coal-based winter heating north of China's Huai River raised PM10 by about 41.7 micrograms per m³, shortening lives.
3. Manhattan's steam system runs about 169 km of pipe to about 1,555 customers, the largest district steam system in the US.

The journey

1. 1 Heat plantBoiler, CHP waste heat or heat pump
2. 2 Hot waterSupplied at 50-120 C, by generation
3. 3 Insulated pipesSteel in foam, buried under streets
4. 4 SubstationHeat exchanger warms the building's own water
5. 5 ReturnCooled water flows back for reheating

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