thermoacoustic
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Waste heat close to becoming useful in cooling / lighting applications
Not that waste heat in general hasn't been repurposed for non-wasteful activities before, but researchers at Doshisha University are now edging ever closer to making useful the previously annoying thermoacoustic phenomenon. For those not really tied into the science realm, said phenomenon is a nonlinear one in which "heated air autonomously transforms into sound when passing through small mesh holes in a wire sheet." Gurus are now developing a cooling technology that would have heat converted to sound, where it would then be transferred through a tube and reconverted into heat; furthermore, other whiz-kids are looking to generate actual electricity from the racket. In related news, the thermoelectric conversion is being used to transform waste heat from candles into energy for LEDs, which would emit more light than the candle powering it. Pop on past the break for a demonstration of the former.
Tiny thermoacoustic engines pave the way for screaming gadgets
Looks like all that heat generated by your laptop may finally be useful for something other than frying eggs -- a group of grad students led by professor Orest Symko at the University of Utah has unveiled an array of "thermoacoustic" engines that turn heat into sound, which can be directed at a piezoelectric mechanism to produce electricity. The US Army-funded research seems promising but is obviously still in its infancy -- one of the designs the researchers demonstrated is half the size of a penny but pumps out 120dB of noise (about the same as a siren), while another bumped out over 135dB, (which is roughly equivalent to a jackhammer). The team expects that future, smaller designs will work at ultrasonic frequencies outside the range of human hearing. Although we're not expecting hybrid-siren-powered laptops to hit anytime soon, you Utes out there may want to invest in some earplugs -- Professor Symko says they'll be testing these designs at the University's water-heating facility in the next year.[Via InformationWeek]
