Illustrative c5 air delivery
6.14 m³/s terminal air; 3.07 kW terminal fan inputmodeled
| Value kind | modeled — Interpret this value according to its displayed kind, scope, source, and as-of date. |
|---|---|
| Scope | Assume the four-rack design of 5.1 leaves 80.0 kW on air. Use air density 1.20 kg/m³, specific heat 1.005 kJ/(kg·K), a 12.0 K rack-air rise, 10.0% terminal bypass, 300 Pa external pressure and 0.600 fan/motor efficiency. For the inlet screen assume 23.0 °C terminal supply, a 27.0 °C equipment limit, 1.0 K reserve, ±0.2 K measurement uncertainty, and hypothetical worst inlets of 25.2 °C normal, 25.6 °C with a terminal unavailable and 26.3 °C with containment open. These exercise 5.1 energy conservation and this chapter’s delivery mechanism; none is an operating measurement. |
| As of | 2026-09 |
| Source | Guide calculation from expressly assumed teaching inputs. Primary reference supplies method or equipment context, not evidence that this design was built or tested. |
| Derivation | Equipment airflow = 80.0/(1.20 × 1.005 × 12.0) = 5.53 m³/s. Terminal airflow = 5.53/0.900 = 6.14 m³/s, using the unrounded equipment flow. Fan input = 6.14 m³/s × 300 Pa / 0.600 = 3.07 kW. This terminal input is separate from server fans already inside the IT meter. The allowed indicated inlet is 27.0 − 1.0 − 0.2 = 25.8 °C. Normal and unavailable-terminal assumptions pass; open containment at 26.3 °C fails by 0.5 K. Restore containment or revise delivery before taking that service state. The crossover is an indicated 25.8 °C, not a rack-kW band. Require the supplier fan curve and inlet map to demonstrate these duties before release. ASHRAE’s data-center environmental guidance supplies the inlet-envelope context; use 13.5 for installed acceptance. |
| Review | checking…cadence-derived review 2027-01-03 · standard cadence |
| Recorded changes | none recorded |
| Claim id | p5-c5-air-delivery |
Where the guide uses it
Not quoted in a chapter yet; it is kept in the curated register.
← Full numbers register — every date-stamped figure in the guide, with revision history.