Stage 2 of 14 / Calculation
Model the AI workload and rack capacity
Turn a heterogeneous rack schedule into installed nameplate, operating average, operating peak, concurrent peak, annual IT energy and growth headroom.
- Advanced
- 14 stages
- 20 min
- Mission-critical electrical and thermal systems
After this stage you can
- Build rack groups with density, count and average/peak load fractions.
- Calculate nameplate, average, peak, concurrent peak, annual energy and growth headroom.
- Identify whether the target capacity is limited by installed racks, concurrent load or future growth.
The engineering
AI racks are not a single density. A training hall may run at 50 kW per rack while an inference hall runs at 12 kW and a network row at 8 kW. The model keeps a separate group for each density and applies an average and a peak load fraction to the provisioned power.
Installed nameplate is not operating demand. A 50 kW rack provisioned for a future GPU generation may draw 35 kW average today and 47 kW at peak. The workbench requires both fractions and rejects a peak below the average. Concurrency is applied to the summed peak, not to each rack independently.
Annual IT energy comes from the operating average multiplied by 8,760 hours. Growth is a compound scalar over the stated horizon. It is a planning allowance, not a deployment schedule, and it must be compared with the owner target before electrical and cooling capacity are fixed.
EngiMetric / AI data-center workbench
One project, computed from rack to report
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Your deliverable for this stage
A rack schedule and IT capacity statement with explicit nameplate, average and peak values.
Stage assumptions, limits and sources
Assumptions
- All racks in a group share the same provisioned power and load fractions.
- Load fractions are assumptions, not measured telemetry.
- Annual IT energy uses a flat 8,760-hour average unless the energy stage applies its hourly shape.
Constraints
- The rack schedule is a capacity model, not a bill of materials for servers.
Limitations
- No GPU workload trace, scheduler, power capping or DVFS model.
- No measured PDU branch-circuit or rack PDU data.
- Growth is not a phased deployment schedule.
Review status
- Needs engineering review
- Professional review is required before publication or use as a design basis.
Sources
- Uptime Institute - Tier Standard overviewengineering org
- ASHRAE - Data Center Guidance and Datacom Seriesengineering org
- Open Compute Project - Data Center Facility projectengineering org
- NVIDIA - DGX SuperPOD reference architectureofficial docs
- U.S. Department of Energy - Data centers and serversgovernment
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Stage kind: Calculation / Journey: ai-data-center / Stage: it-capacity