Stuttgart 21 transport hub designed to operate without air conditioning

The Stuttgart 21 megaproject, a massive subterranean transport hub in Germany, is designed to operate entirely without artificial air conditioning. This design choice has drawn public scrutiny following record-high summer temperatures.

Deutsche Bahn (DB) defends the decision, stating that the station's underground location in a basin will help maintain stable temperatures during extreme heat and cold. The cooling mechanism relies on air traveling through tunnels between 3 and 9.5 kilometers in length. This natural airflow is intended to be aided by the movement of passing trains and glass 'light eyes' equipped with automated ventilation flaps.

Jörg Hamann, head of communications for Deutsche Bahn, noted that eliminating heating and cooling could significantly reduce the hub's long-term carbon footprint. This aligns with efforts to lower emissions, as the International Energy Agency (IEA) reports that air conditioning contributes approximately one billion tonnes of CO2 annually.