Cooling
Why air stops
Moving heat with air needs airflow and fan power that become impractical above roughly 20 to 30 kW per rack. NVL72-class racks cool GPUs and CPUs with liquid, but power supplies, NICs and some switches still reject heat to air, so every liquid-cooled hall keeps some air handling.
Source: https://pantheon.run/learn/nvidia-gb200-nvl72-power-and-cooling Checked 2026-09-18
| Figure | Value | Source |
|---|---|---|
| Practical air ceiling | 20 to 30 kW per rack | https://www.vertiv.com/en-ca/insights/articles/educational-articles/data-center-containment-strategies-for-high-density-environments/ Opened 2026-10-06: Vertiv's containment article gives 20-30 kW per rack for air-cooled rows. Re-sourced from pantheon.run, whose page carries no such figure. This is a vendor's rule of thumb, not a standard. |
| GB200 NVL72 rack | NVIDIA reference rack about 120 kW; HPE's OEM configuration rated 132 kW nominal, about 192 kW peak design power | https://pantheon.run/learn/nvidia-gb200-nvl72-power-and-cooling |
| GB300 NVL72 rack | 132 to 155 kW by configuration | https://www.supercomputing.news/emerging/nvidia-45c-warm-water-cooling-mgx-data-center |
| Liquid to air split | about 115 kW liquid, 17 kW air (87 / 13 %) | https://pantheon.run/learn/nvidia-gb200-nvl72-power-and-cooling unverified Unsourced. The pantheon.run page cited here carries no liquid-to-air split. HPE's product page for the GB200 NVL72 was opened in a browser on 2026-10-07: it describes a mix of air and liquid cooling but gives no kW or percentage figures. The figure may be in HPE's QuickSpecs, which were not read. |