Hydrogen vehicles for all seasons

University scientists are part of a team headed by Nuvera Fuel Cells Inc. of Cambridge, Mass., that has won a $5 million U.S. Department of Energy grant for research and development of fuel cells.

Michael H. Santare, professor of mechanical engineering, and Anette M. Karlsson, associate professor of mechanical engineering, are leading the efforts at the University, where the federal funding will support research on polymer electrolyte membrane fuel cells (PEMFCs). Santare says such fuel cells have many potential benefits for transportation applications.

Among those benefits are increased fuel efficiency, lowered harmful emissions and a reduction of the world’s dependence on petroleum, he says.
However, he notes that a number of technical barriers still remain and must be overcome before PEMFCs can be commercially successful on a large scale. One of the most challenging issues for PEMFC-powered vehicles is start-up and shut-down in cold weather.

Because water transport through the membrane is an essential part of the operation of the fuel cell, subfreezing temperatures can impose large stresses on the system as the water freezes, Santare says. These stresses, in turn, can cause premature mechanical failure of the fuel cell.
Furthermore, if water remains in the system after shut-down, it could freeze and further stress the system.

“The need for improved lifetime of PEMFC necessitates that the freeze-thaw behavior be understood clearly and that mechanical models be developed so that new materials and system designs can be introduced to improve the cold temperature performance,” Santare says.

“In automobile applications, the requirement on durability is very high,” Karlsson says. “We don’t expect to have to take the car in for service once a month. In fact, we don’t expect to have to do anything to maintain the car. To ensure a reliable design of a fuel cell, we must therefore understand how it behaves over a long time, for all possible conditions.

“The fuel cell gets frozen several times during the winter and might run very hot during operation in the summer. Each extreme event accumulates a small damage and we must interpret this damage into our models to predict how the material degrades with time.”

The grant, she says, “is an important addition to the ongoing and growing effort in the mechanical engineering department on clean energy, where more than half a dozen faculty members are actively conducting research.”

In addition to Nuvera and UD, other partners in the project are W.L. Gore & Associates and SGL Carbon Inc.

The grant was awarded through the same federal Department of Energy Program that is supporting related work on fuel cells by Jingguang Chen, professor of chemical engineering and director of the Center for Catalytic Science and Technology, and Brian Willis, assistant professor of chemical engineering. (See article on preceding page.)

“The Department of Energy is committed to breaking our addiction to oil by creating a diverse portfolio of clean, affordable and domestically produced energy choices,” U.S. Energy Secretary Samuel W. Bodman said in announcing the award, part of $100 million in grants announced by the agency.

“We expect hydrogen to play an integral role in our energy portfolio, and we are eager to see hydrogen fuel cell vehicles on the road in the near future.”

Both teams’ research efforts also are related to a pilot project in which a shuttle bus powered by hydrogen fuel cells now is operating on the UD campus. (See article on pages 26-27.)

At a ceremony launching the bus, U.S. Sen. Thomas R. Carper of Delaware said the University has made significant contributions in alternative energy research.

“Our country and our world are at the crossroad,” Carper said during the ceremony. “The decisions that we make in the next 10 years in public policy, in research and development, in lifestyle changes, could determine the fate of our way of life in 50 years, 100 years from now.
“Today, there is still time to make a difference. The University and leaders throughout our state will help to make that difference.”

Santare has research interests in applied mechanics and composite materials. He received a doctorate from Northwestern University, joined the UD faculty in 1986 and was a Fulbright Distinguished Visiting Professor at the Universidade do Porto in Portugal in 2001.

Karlsson has interests in the thermo-mechanical properties and response of advanced and traditional materials. She received a doctorate in mechanical and aerospace engineering from Rutgers University and conducted postdoctoral research at Princeton University before joining the UD faculty in 2002. She is the recipient of the 2004 Office of Naval Research Young Investigator Award and the 2005 Francis Alison Young Scholars Award from the University.

—Neil Thomas, AS ’76