Power Usage Effectiveness
PUEBack to Glossary
Cooling
Direct Liquid Cooling
DLC
Cooling method bringing liquid directly to heat-generating components, enabling high-density rack deployments.
Unit: kW per rack
Full Definition
Direct Liquid Cooling (DLC) removes heat from processors, GPUs, and memory by circulating coolant through cold plates or immersion tanks in direct contact with heat-generating components. Unlike air cooling, DLC sustains rack densities of 100 kW or more — essential for modern GPU clusters (NVIDIA H100/H200, AMD MI300X). The three main approaches are: rear-door heat exchangers (passive), direct-to-chip cold plates (active CDU), and full immersion (single or two-phase). DLC significantly reduces hot air in the data hall and often achieves PUE below 1.05.
Also Known As
dlcliquid coolingimmersion coolingcold plate coolingdirect to chip
Source Reference
ASHRAE TC9.9 Liquid Cooling Guidelines (2024); Open Compute Project Liquid Cooling