Sandia National Laboratories used a new technique that successfully halved the amount of water used to cool a high-performance data center at the National Renewable Energy Laboratory (NREL); the technique substituted a reusable liquid refrigerant in place of evaporative-water cooling towers.

The thermosyphon hybrid cooling system saved 1.16 million gallons of water in the first year of operation, cutting the data center’s onsite water usage in half, while continuing to operate at optimal energy efficiency, according to the DOE. The engineer who created the technique was awarded the DOE’s Federal Energy and Water Management Award.

Sandia will install a system using the technique at its own facilities in 2019, Martinez says (via Process Cooling magazine). He believes the water savings will be even more significant at Sandia, which has more high-performance computers.

The cooling process for the refrigerant relies upon convection rather than requiring an electrically powered pump. “The hot water from the data center causes the refrigerant to turn from liquid to gas, which removes energy through the phase change.  The refrigerant then rises to a heat exchanger where the outside air cools it off so that it can re-liquefy. The liquid refrigerant then returns to the original reservoir via gravity and the process starts again,” Sandia says.