SALT LAKE CITY Acoustically coupled transducers can directly generate electricity from heat, researchers reported on June 8 during the annual meeting of the Acoustical Society of America here. "We have a new source of renewable energy from waste heat," said University of Utah professor Orest Symko.
The team's so-called thermoacoustic prime mover consists of back-to-back heat exchangers with an intervening stack of materials tuned to a resonant acoustic frequency. When heat goes in, a resonant sound is generated and acoustically coupled to a piezoelectric transducer, which converts the sound into electricity.
The heat-driven electricity generator is an Army-funded project that aims to generate electricity while cooling radar systems. Symko's group, in cooperation with Washington State University and the University of Mississippi, is investigating methods to improve the efficiency of their heat-driven acoustically coupled electricity generators. Ultimately, the idea is to also directly convert solar heat into electricity.
So far the team has demonstrated only laboratory desktop prototypes, but their Army contract calls for a prototype electricity generator that harvests the waste heat from the university's hot-water plant next year, with the aim transferring that technology to cooling a real military radar the year after. The researchers estimate that it will take an additional two years to develop a model that harvests the sun's heat directly.
The technology, according to Symko, has a wide range of possible applications, from cooling electronics in small portable devices to directly generating electricity from the heat in nuclear power plants without the giant steam turbines.