Study: Focus on Systems, Not Materials, for Reducing Desalination Technologies' Energy Consumption

Despite an emphasis on discovering novel materials to improve the energy efficiency of water desalination, a team of Yale researchers asserts that these efforts show little benefit. The time and resources, they say, would be better spent on improving other aspects of desalination, such as system design. 

The study, which comes from the laboratory of Menachem Elimelech, the Roberto C. Goizueta Professor of Chemical & Environmental Engineering, was published Friday in Energy & Environmental Science.

“There are all these materials that come with great promises for reducing the energy consumption of desalination, but the materials have a very small measurable impact,” said Elimelech. “With system design, you can improve energy efficiency much more than with any novel material.”

Global water scarcity is one of the greatest environmental threats and the need to harness unconventional water sources is paramount - this includes the development of water desalination processes. Three of the most commonly researched desalination technologies are reverse osmosis, solar thermal desalination, and capacitive deionization. Energy consumption for these technologies remains a chief concern and a prominent area of investigation among researchers in the field.

Research aimed at minimizing the energy consumption has increasingly focused on developing new materials to accomplish this. However, the Elimelech research team systematically analyzed the approach of using advanced materials to enhance the energy efficiency of reverse osmosis, solar thermal desalination, and capacitive deionization. They found that advanced materials offer little to improve energy efficiency. Instead, the researchers identified several system- and design-based approaches with significantly greater potential to augment energy efficiency.

“We suggest more meaningful applications of novel materials, such as enabling greater selectivity (water-solute or ion-ion) and improved process reliability,” said lead author Sohum K. Patel, a Ph.D. student in Elimelech’s lab. “In contrast to materials, we emphasize the potential of process design in enhancing desalination energy efficiency.”

The study’s other authors are Cody L. Ritt, Akshay Deshmukh, Zhangxin Wang, Mohan Qin, Razi Epsztein.