High-Performance Computing Data Center Warm-Water Liquid Cooling

NREL's High-Performance Computing Data Center (HPC Data Center) is liquid cooled for energy efficiency, taking advantage of the fact that liquid has approximately 1,000 times the cooling capacity of air.

Liquid cooling technologies offer a more energy-efficient solution that also allows for effective reuse of heat rejected by the computing equipment. And rack power densities of 60 kilowatts (kW) per rack or more can be achieved using warm-water liquid cooling, which requires less floor space.

NREL's HPC Data Center is cooled without mechanical refrigeration, as indirect evaporative cooling takes advantage of NREL's semi-arid climate with 60°F design wet-bulb temperature. The relatively warm (up to 75°F) water used for computer cooling allows the data center to use highly efficient evaporative cooling towers.

Water circulates through heat exchangers in the HPC systems to efficiently capture waste heat. The water is heated to around 100°F by the HPC systems and used as a source of heating for laboratory and office spaces in the ESIF.

Key design parameters for NREL's liquid-cooled data center include IT cooling supply and IT return water, as the ESIF can only produce 75°F on the hottest day of the year with cooling towers, and the building requires at least 95°F to heat the facility on the coldest day of the year.