NSF engineering research centers take on heat and water

New methods for increasing the power density of electric systems used in transportation and more efficient and improved water treatment technologies are the focus of two new engineering research centers announced by NSF in August.

Led by the University of Illinois at Urbana-Champaign, the Center for Power Optimization of Electro-Thermal Systems (POETS) will aim to increase the power density of electrified systems by 10 to 100 times. That increase should lead to lighter, more compact, and more efficient power electronics for cars, airplanes, construction equipment, tools, and other mobile applications. Center researchers will integrate three-dimensional cooling circuitry, power converters, and algorithms to improve power management. Success could lead to a doubling of the range of electric vehicles, according to center officials. The NSF award is valued at $18.5 million over five years.

Andrew Alleyne, POETS’s principal investigator, says that while heat dissipation limits power density, thermal considerations are often viewed as a problem to be solved only after the power electronics have been designed. “We take a multidisciplinary approach,” he says. “We have electrical engineers, mechanical engineers, materials scientists, and physicists.” The objective is to codesign electronics from the beginning to take account of thermal and electric limits.

“It took people who knew computational algorithms and numerical methods, and people who knew semiconductors and chip design, to come up with ways bit by bit to keep climbing up the Moore’s law path,” he says. “Similarly, we are going to need to have folks who know the mechanical, materials, and thermal side and people who know the electrical power electronics side. Together we will keep climbing up the ladder of increased power density.”

The early stages of the research program will involve a considerable amount of physics, says Alleyne. “We’re going to be building up a thermal equivalent of electrical circuits. That is, we’ll be building a thermal diode or gate, the thermal equivalent of a capacitor, and the equivalent of a thermal potentiometer. If we can build these components, we can route thermal power throughout a volume, in a fashion similar to routing electrical power—clearly not as fast, but as easily.”

Stanford University, Howard University, and the University of Arkansas are partners in the center, which will engage up to 25 faculty and 50 students, Alleyne says.

Rice University is the recipient of a five-year NSF award, also valued at $18.5 million, for the Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment Systems. Principle investigator Pedro Alvarez says the goal is to develop modular, portable, and more efficient catalytic and physical water-treatment processes.

As one example, Rice scientists found that when electrons in some nanoparticles are excited by sunlight, they produce water vapor. “If you put these particles on the surface of a hydrophobic membrane, water vapor can get on the other side, leaving behind salt and other pollutants and microbes,” he explains.

The center will also look at enhancing reverse-osmosis membranes (see the Quick Study by Greg Thiel, Physics Today, June 2015, page 66) that won’t get clogged or biofouled. Possible improvements include coatings and antimicrobial particles.

“We are still using Victorian-era technologies like sand filters” for water treatment, Alvarez notes. “They work very well to remove suspended solids and bacteria. But what about endocrine disrupters, or pharmaceuticals, or trace-level carcinogens? Current systems aren’t doing a very good job” of eliminating them, he says.

Other technology options for improving treatment include sorbents and catalysts. Self-assembling nanoparticle surfaces might be used to reduce biofouling and corrosion in water distribution systems.

Partnering with Rice are Arizona State University, the University of Texas at El Paso, and Yale University. Alvarez expects about 20–30 faculty members and 200 students to participate in center research.

Including the new pair, NSF supports 20 engineering research centers in the areas of advanced manufacturing; biotechnology and health care; energy, sustainability, and infrastructure; and microelectronics, sensing, and information technology.