As GPU power consumption exceeds 700W per accelerator and rack densities climb past 100 kW, traditional air cooling has reached its physical limits. Liquid cooling is no longer optional for AI-focused data centers; it is a fundamental infrastructure requirement that must be planned from the facility design stage.
Direct-to-Chip vs. Immersion Cooling
Direct-to-chip liquid cooling attaches cold plates to GPUs and CPUs, circulating coolant through a closed-loop system to facility-level cooling distribution units. This approach integrates with existing rack infrastructure and is the most widely deployed liquid cooling method, supported by vendors like CoolIT and ZutaCore.
Single-phase and two-phase immersion cooling submerge entire servers in dielectric fluid, achieving the highest heat removal efficiency. While immersion cooling can handle rack densities exceeding 200 kW, it requires specialized tanks, fluid management systems, and maintenance procedures that differ significantly from traditional server operations.
Rear-door heat exchangers provide a middle-ground solution for facilities transitioning from air cooling. By attaching a liquid-cooled coil to the rear of standard racks, they can supplement air cooling capacity by 30-50 kW per rack without modifying the servers themselves.