The campus is not just for expending youthful energy. As a group of University of Maryland students showed recently, it is also a place for saving energy — by designing better appliances.

A team of engineering students, known as UMD Dryer, has won a year-long nationwide student competition in heavy-duty energy saving by designing an “ultra-efficient two-stage heat pump clothes dryer,” the university said.

An arm of the U.S. Energy Department sponsored the design competition for ultra-low-energy use appliances to spur their development.

Improving dryers may not seem a key academic concern, but it could save kilowatt hours by the billion. According to one federal estimate, household dryers in 2011 used 57 billion kilowatt hours of electricity. Authorities said U-Md.’s device could cut that by 40 percent.

The student leader of the UMD team, Tao Cao, said it was rewarding to be on it, and faculty leader Yunho Hwang said members really wanted to save energy, “more than just taking a class.”