CASE38 · Data centers · PUE, EC fans and free cooling
Using multi-center PUE diagnosis to prioritize EC fans and free cooling
Center and floor-level PUE is traced to cooling operation and equipment condition. A measured fan pilot is kept separate from the estimated benefits of larger rollout and free-cooling investment.
01 · CASE ANALYSIS
Diagnostic challenge
Center averages hid floor-level cooling anomalies, overcooling and fan-only operation. Comparable total, IT and cooling metering was necessary before ranking centers.
The project linked PUE and cooling indices to operating-unit counts, equipment COP, temperatures and control states.
02 · CASE ANALYSIS
Field data and pilot boundary
Two centers piloted replacement of existing cooling-unit supply fans with efficient EC fans. Before/after fan-power comparison reported a 63.5% reduction.
The result applies to pilot supply-fan power. It is not a 63.5% reduction in whole-center electricity or total cooling electricity.
| Measure | Value | Status |
|---|---|---|
| EC-fan pilot at two centers | 63.5% fan-power reduction | Reported pilot result |
| Expansion to approximately 400 cooling units | Approximately 55% fan-power reduction | Estimated rollout |
| Free-cooling expansion | KRW 426 million/year | Investment-study potential |
| Tower/cooling-system settings | No completed saving quantified | Follow-up diagnosis/test |
03 · CASE ANALYSIS
Scaling and free-cooling opportunities
An expansion scenario targeted approximately 400 poor-performing cooling units at major centers. Estimated fan-power reduction was approximately 55%.
A separate free-cooling study evaluated increasing the fraction of cooling supplied by favorable outdoor conditions. It assessed investment and payback rather than reporting completed savings.
04 · CASE ANALYSIS
Economics and implementation status
EC-fan expansion was estimated at KRW 1.1 billion/year benefit and KRW 2.2 billion investment, with roughly two-year simple payback.
Free-cooling expansion was estimated at KRW 426 million/year benefit and KRW 1.757 billion investment, with approximately 4.13-year simple payback. Cooling-tower temperature tests and other equipment reviews required follow-up.
| Scenario | Annual expected benefit | Estimated investment | Simple payback |
|---|---|---|---|
| EC fans | KRW 1.1 billion | KRW 2.2 billion | Approximately 2 years |
| Free cooling | KRW 426 million | KRW 1.757 billion | Approximately 4.13 years |
05 · CASE ANALYSIS
M&V and engineering lesson
Validate total/IT/cooling meters and adjust comparisons for IT load, outdoor conditions and service temperatures. Confirm fan airflow and thermal conditions when comparing power.
Use pilot results to inform rollout assumptions, while maintaining separate evidence for each measure.
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