By Rob Goodier
A device rigged with a loudspeaker and other cheap components can clean up a dirty, woodburning cookstove and convert it into a power generator. It’s a small thermoacoustic generator that attaches to the stove to convert heat into sound waves and then into electricity. The concept is rooted in NASA space probe propulsion technology, but it is affordable enough for use in developing regions.
Paul Montgomery, a recent mechanical engineering graduate of Pennsylvania State University, developed a working prototype of the device last year. As he explains, it uses the stove’s leftover heat to produce a high-amplitude sound wave within a resonator. It then channels the wave through a loudspeaker operating in reverse to generate electricity. The advantages are its low cost—projected at about $25, it has no moving parts other than the loudspeaker, and it could be more efficient than a thermoelectric generator.
