A hybrid cooling system cut direct water use at an operating national-laboratory data center.
- Maturity
- Deployed, stage 4 of 4
- Support
- 1 source · report
- Evidence detail
- How we know ↓
GOLDEN, COLORADO / COOLING DESIGN
DOE reports that NREL’s 10,000-square-foot high-performance-computing facility used warm-water liquid cooling and a thermosyphon to avoid 2.10 million gallons over two years. An open cooling tower remained available for peak conditions.
Move heat efficiently, then choose how to reject it
Warm liquid carries heat away from computing equipment more directly than room air. When outdoor conditions allow, the thermosyphon rejects that heat without the cooling tower’s normal evaporation. The facility retained its tower for peak conditions, making this a hybrid system rather than a water-free one.
DOE reported 1.16 million gallons avoided in the first year and 2.10 million over two years. The figures describe one operating federal HPC facility, not a universal result for larger commercial campuses.
The climate and operating envelope set the result
The approach depends on warm-water equipment, outside conditions that support passive heat rejection, and controls that can switch between modes. A different climate, density, reliability requirement, or water source changes the balance.
A useful proposal should therefore publish the full cooling sequence, expected hours in each mode, site water withdrawals and consumption, and actual metered performance after operation begins.
How we know1 source · checked 2026-09-19 · no corrections
Original sources
Institutions: National Renewable Energy Laboratory · U.S. Department of Energy · Johnson Controls · Sandia National Laboratories
- Maturity
- Deployed
- Claim confidence
- high
- Source published
- 2019-05-01
- Captured
- 2026-09-19
- Last source review
- 2026-09-19
- Editorial method
- AI-assisted source review
- Place / relevance
- Golden, Colorado · operating-facility
Bright compared this account with the linked original and supporting sources and kept reported, budgeted, projected, and observed claims distinct. Bright did not independently audit the underlying records.
Maturity describes the tested or operational setting. Confidence describes support for the particular claim; one does not determine the other.
Revision & correction history
2026-09-19 · Published the two-year DOE operating case with its facility scale, retained wet-cooling capacity, and direct-water boundary explicit.
No corrections recorded.