A new cooling method for supercomputer systems is picking up steam – literally. After saving millions of gallons of water at a National Renewable Energy Laboratory (NREL) datacenter, this innovative approach, called “thermosyphon cooling,” was installed at Sandia National Laboratories in Albuquerque, New Mexico. There, Sandia has announced, the thermosyphon cooling has already saved over half a million gallons of water during its first six months of operation.
Thermosyphon cooling works by funneling the heat produced by datacenters through pipes surrounded by an outer shell containing a liquid refrigerant. As the pipes heat up, the heat evaporates the refrigerant, allowing it to rise into a cooling chamber where it condenses back into a liquid. This method dramatically reduces the need for evaporative cooling towers, which are often costly in terms of water and energy. If the atmospheric temperature is greater than the temperature of the refrigerant, however, the heat transfer operates the wrong way and mechanical chillers are utilized as a backup measure.
At NREL, thermosyphon cooling saved 1.15 million gallons of water over the course of a year while installed on a datacenter in Golden, Colorado. For his work to develop the method and install it at NREL, David J. Martinez, project lead for Sandia’s infrastructure computing services, won the 2018 Department of Energy’s Federal Energy and Water Management Award, which recognizes contributors to energy and water efficiency in the federal government.
Following the successful implementation at NREL, a thermosyphon cooling unit was installed at Sandia in 2019. Over its first six months of operation, thermosyphon cooling saved 554,000 gallons of water – as well as over 195,000 kilowatt-hours of electricity. In sunny New Mexico, where Sandia is located, thermosyphon cooling is viable throughout the year except during summer daytimes, when the environmental temperature is too high.
At $200,000 per unit, Sandia is being relatively cautious – especially since the payback period for thermosyphon coolers is roughly ten years. For now, Sandia is just using one thermosyphon cooling unit, but it has already purchased two more and is considering a fourth. The impact of four units would be substantial: cost savings of roughly $65,000 a year and annual water savings of nearly 17 million gallons.
“We’re testing out the system because that’s what national labs do: we’re among the first to try things,” said Martinez. “Others may come along when they see our success.”
Header image: A thermosyphon cooler on the roof of Sandia’s supercomputer center is inspected by engineering project lead David J. Martinez. Image courtesy of Randy Montoya via Sandia National Laboratories.