As CERN's main energy optimization lever, cold production at the Prévessin-Moëns data center is carried out by "drycoolers". This innovative equipment avoids the need for energy-hungry chillers, by making the most of a resource that's as local as it is inexhaustible: the relatively cool air temperature of the Ain region! Powered by 8 adiabatic drycoolers (16 MWf), measuring around 12 metres long and 4 metres high, cold production is ensured by redundancy and a tempered water loop capable of oscillating between 22°C and 32°C. In concrete terms, the data center's drycoolers use outside air to cool the closed water loop, which ensures the refrigeration of the servers and the smooth running of their electronic components. In summer, when the outside air rises above 22°C, the drycoolers switch to "wet mode". Water trickles down onto damp cardboard, which in turn cools the water loop by evaporation. To further reduce the data center's water consumption, run-off water from the drycoolers is collected in tanks, achieving a consumption of less than 0.331 L / KWh IT. In each room, five huge fanwalls distribute cold and ensure that the overall target temperature, set at 26°C by CERN, never drifts above 32°C.