Cooling method could relieve heat woes in data centers, electric vehicles

Electronic systems, such as electric vehicles and large data centers, generate a lot of power, which creates tremendous heat. An engineer at Washington University in St. Louis has developed a unique evaporative cooling system using a membrane with microscopic pillars designed to remediate the heat, ultimately improving performance.

Damena Agonafer has developed a unique evaporative cooling system that uses a membrane with microscopic pillars (shown above) that are designed to remediate the heat from high-power electronic systems.

The method, developed by Damena Agonafer, assistant professor of mechanical engineering & materials science, is the first approach to retaining liquids using microfabricated micropillar structures. His theoretical, computational and experimental analyses are published in the March 15 print issue of the Journal of Colloid and Interface Science.

While a postdoctoral researcher at Stanford University, Agonafer developed a method to mitigate high heat-flux generation using water. However, water cannot be used safely in electrical applications, so Agonafer uses dielectric liquid, such as refrigerant, an electrical insulator in high voltage applications that has low surface tension. Unlike water, dielectric refrigerant, a low surface-tension liquid, can "wet" any standard surface.

"This work is the first demonstration of low-surface-tension liquid within porous membrane structures," Agonafer said. "There are many ways to retain liquid inside or behind the porous membrane structure with high surface-tension liquid, such as water, with surface chemistry, but you can't do any type of surface treatment with low surface-tension liquid, so this requires a certain type of microstructure to form an energy barrier and 'pin' these liquids."

This advanced cooling technology will help unleash the full potential of next-generation electronics for a broad array of applications, including renewable energy storage, autonomous driving and public transportation, artificial intelligence, advanced communications and health care.

The McKelvey School of Engineering at Washington University in St. Louis promotes independent inquiry and education with an emphasis on scientific excellence, innovation and collaboration without boundaries. McKelvey Engineering has top-ranked research and graduate programs across departments, particularly in biomedical engineering, environmental engineering and computing, and has one of the most selective undergraduate programs in the country. With 140 full-time faculty, 1,387 undergraduate students, 1,448 graduate students and 21,000 living alumni, we are working to solve some of society’s greatest challenges; to prepare students to become leaders and innovate throughout their careers; and to be a catalyst of economic development for the St. Louis region and beyond.

Agonafer D, Lee H, Vasquez P, Won Y, Jung K, Lingamneni S, Ma B, Shan L, Shuai S, Du Z, Maitra T, Palko J, Goodson K. Porous micropillar structures for retaining low surface tension liquids. Journal of Colloid and Interface Science, Dec. 14, 2017 online; March 15, 2018 print. DOI.

This research was supported by funding from DARPA and the NSF Funded Center for Power Optimization of Electro-Thermal Systems.