Vertiv 360AI High Density Reference Design #027: 2x NVIDIA Blackwell DGX SuperPOD (GB300 NVL72)

Overview

This 2025 design is a 2.5 MW GB300 NVL72 hall. Total IT is 2,512 kW (1,256 kW per pod), with 16 compute racks at 142 kW and 24 support racks at 10 kW, 40 racks in all. Cooling is 77% liquid and 23% air. The IT UPS is 4 x 1,000 kVA in 4-to-make-3 for two pods and the facility UPS is 2 x 240 kVA 2N. Distribution has 8 x 500 kVA PDUs, 8 x 400 A (240/415 V) busbars per pod and 2 x 60 A tap-offs per rack per busbar.

Unusually for the series it offers three thermal options. Option 1 is CDU plus CRAH plus a free-cooling chiller: 2 x 1,350 kW CDUs per pod at N+1, 3 CRAHs per pod (N+2 across the two pods) and 3 free-cooling chillers at N+1, running 30% propylene glycol. Option 2 uses in-row/rack CDUs with pumped-refrigerant air units, option 3 an integrated DH-series unit. In options 2 and 3 the chip-loop supply temperature is about 24 degC (23.8 degC / 75 degF).

The document's distinctive contribution is the mechanical UPS load calculation: (20.5 kW x 2 CDUs + 17 kW x 3 CRAHs) x 2 pods = 184 kW. It makes plain that when CDU pumps and CRAH fans ride on UPS, the IT UPS carries a further 184 kW. The document forecasts rack density toward 1 MW per rack; vendor values remain indicative.

Key points

1. Total IT 2,512 kW (1,256 kW per pod); 16 racks at 142 kW + 24 racks at 10 kW (40 racks).
2. Cooling split 77% liquid / 23% air.
3. IT UPS 4 x 1,000 kVA in 4-to-make-3 for two pods; facility UPS 2 x 240 kVA 2N.
4. 8 x 500 kVA PDUs; 8 x 400 A 240/415 V busbars per pod; 2 x 60 A tap-off per rack per busbar.
5. Compute racks 8 x 33 kVA DC power shelves; support racks 2 x 33 kVA shelves (2N).
6. Option 1: 2 x 1,350 kW CDU per pod N+1; 3 CRAH per pod; 3 free-cooling chillers N+1 with 30% propylene glycol.
7. Mechanical UPS load: (20.5 kW x 2 CDUs + 17 kW x 3 CRAHs) x 2 pods = 184 kW.
8. Chip-loop supply fluid 23.8 degC (75 degF) in options 2/3.

Using it in design

• Implement mechanical UPS sizing explicitly: mechUpsKw = sum of CDU pump kW + CRAH fan kW for every unit that must ride through; default about 20 kW per 1.35 MW CDU (roughly 1.5% of liquid load) and about 17 kW per CRAH.
• Offer the three thermal options as selectable cooling architectures for a liquid hall.
• Default TCS supply temperature to 24 degC for GB300-class cold plates; assume 30% propylene glycol on free-cooling loops and apply the capacity derate.

Who should read it

Engineers choosing a cooling architecture for a liquid-cooled hall and sizing its mechanical UPS load.

Related standards

• ASHRAE TC9.9 Liquid Cooling Guidelines (W27/W32)
• OCP Open Rack V3
• Uptime Tier Standard: Topology

Publication details

Authors

Vertiv

Publisher

Vertiv

Year

2025

Document number

AI Reference Design #027

Document language

English

Source type

Manufacturer

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation