175 Percent More Efficient Refrigeration

If a new "smart" metal could help cool your home or refrigerate your food 175 percent more efficiently than current technology, imagine what that would do for your electric bills.

Researchers at the Clark School are developing a new "thermally elastic" metal alloy for use in advanced refrigeration and air conditioning systems. The technology promises far greater efficiency and reductions in greenhouse gas emissions.

The Clark School team will soon begin testing of a prototype system, with economic stimulus funding from the U.S. Department of Energy. The new grant is part of a program designed to bring "game-changing" technologies to market.

"Air conditioning represents the largest share of home electric bills in the summer, so this new technology could have significant consumer impact, as well as an important environmental benefit," says Eric Wachsman, director of the University of Maryland Energy Research Center (UMERC).

"The approach is expected to increase cooling efficiency 175 percent, reduce U.S. carbon dioxide emissions by 250 million metric tons per year, and replace liquid refrigerants that can cause environmental degradation in their own right," Wachsman adds.

The lead researchers on the project, Ichiro Takeuchi, Manfred Wuttig and Jun Cui, materials science engineers at the Clark School, have developed a solid coolant to take the place of fluids used in conventional refrigeration and air conditioning compressors. Their system represents a fundamental technological advance, they say.

In the next phase of research, the team will now test the commercial viability of their smart metal for space cooling applications. The 0.01-ton prototype is intended to replace conventional vapor compression cooling technology. Instead of fluids, it uses a solid-state material - their thermoelastic shape memory alloy.

This two-state alloy alternately absorbs or creates heat in much the same way as a compressor-based system, but uses far less energy, the Maryland team explains. Also, it has a smaller operational footprint than conventional technology, and avoids the use of fluids with high global warming potential.

General Electric Global Research and the Pacific Northwest National Laboratory are partnering with the Clark School on the project.

The Department of Energy has given the team $500,000 - one of only 43 grants nationwide - as part of its Advanced Research Projects Agency-Energy (ARPA-E) program, designed to advance out-of-the-box, transformational research from the laboratory to marketplace. The grants are funded with money from the federal American Recovery and Reinvestment Act.

"These grants are highly competitive and require a demonstration that the technology has genuine commercial potential," Wachsman explains. "This represents a significant investment in the state of Maryland and the development of its 'green' economy."

Wachsman, who has been on the job at Maryland for about eight months, is working to make UMERC the campus focal point of interdisciplinary energy research.

He's also submitted a proposal to the Department of Energy to locate a $130 million multi-institutional research hub in the Washington, D.C., region, focusing on a broad array of green building research (including including technology such as this). The agency is expected to make a decision next month on the highly competitive grant.

The grant to develop Maryland's solid-state coolant is part of a $92 million package of ARPA-E awards distributed to 18 states.

The ARPA-E program stems from a recommendation contained in the 2006 National Academies report, Rising Above the Gathering Storm - a report co-authored by University of Maryland President C.D. Mote, Jr.

Designed to spur U.S. innovation, the program was established in the 2007 America Competes Act.

Published July 16, 2010