At 120kW per rack, air alone stops being a cooling strategy and becomes a fire hazard with extra steps. Our halls stay under 1.2 annualized PUE — here is the stacked system that gets them there.
Direct-to-chip first, air second
Every accelerator in our high-density rows sits on a cold-plate loop carrying water at 32°C supply. The loop removes roughly 80% of rack heat before air ever touches it, which means the room air handlers only deal with the remainder — VRMs, DIMMs, fabric and power shelves.
Free cooling most of the year
Ashburn gives us roughly 7,000 hours a year when outside air — or a dry cooler looking at it — can carry the load without compressors. Our economizer plant switches modes automatically, and the PUE curve we publish each month shows exactly when it did.
- Below 55°F ambient: full economizer, compressors off.
- 55–75°F: partial economizer with trim cooling.
- Above 75°F: mechanical cooling, loop temperatures float up to save lift.
Efficiency is a metering problem first. You cannot optimize a kilowatt you cannot see — so we submeter everything down to the rack.
What this means for your invoice
Power passes through at wholesale plus a fixed delivery fee, so every tenth of PUE we shave lands directly in your bill. Clients running sustained training typically see 18–24% lower energy cost per petaflop-hour than in legacy air-cooled space.
