UT Austin Researchers Model Desalination for Data Center Cooling

University of Texas at Austin researchers modeled desalination pathways for data-center cooling, testing whether salty water could ease demand on local freshwater supplies despite higher energy use and treatment costs.

The analysis covers brackish groundwater, seawater and produced water, the liquid brought to the surface during oil and gas production. The modeled systems target water with less than 500 parts per million of total dissolved solids. Feed salinities range from 5,000 parts per million for brackish water and 35,000 for seawater to at least 50,000 for produced water. Treatment options include two-stage reverse osmosis, mechanical vapor compression and hybrid configurations. The study models desalination of produced water, not its use untreated as coolant.

In one produced-water scenario, mechanical vapor compression paired with minimum liquid discharge treated feed at 50,000 parts per million salinity. The model yielded 753 liters of freshwater for every 1,000 kilograms of feed, using 36 kilowatt-hours per cubic meter of permeate. The water cost was $10.4 per cubic meter of permeate.

Across the modeled feedwater types, minimum or zero liquid discharge improved freshwater recovery by 4% to 220% compared with conventional brine disposal. Those approaches also raised energy use by more than 12% and water costs by more than 15%.

Among three data-center scenarios, Longview, Texas, had the lowest local water-stress result under the Saline Water Utilization Intensity measure. That case used brackish groundwater and two-stage reverse osmosis rather than produced water. The analysis describes modeled cases, not an operating installation.

“We can solve parts of this problem with the technology we already have; there’s just a cost to it,” said Vaibhav Bahadur, a professor in UT Austin’s Walker Department of Mechanical Engineering.

Texas officials have also taken steps involving data-center water use. On Sept. 21, Gov. Greg Abbott directed the Texas Commission on Environmental Quality (TCEQ) to halt permits sought by data centers until the Electric Reliability Council of Texas (ERCOT) completes its audit. On Thursday, Oct. 15, Attorney General Ken Paxton sent letters to 156 data-center developments seeking current and accurate water-use information. The permit halt is tied to ERCOT’s completion of the audit.