Heat to Sound to Electricity

I found this nifty bit of technology via Boing Boing. What's even cooler, for me, anyway, is that it was developed by a guy at my first Alma Mater, the University of Utah. Check this out from Science Daily:

University of Utah physicists developed small devices that turn heat into sound and then into electricity. The technology holds promise for changing waste heat into electricity, harnessing solar energy and cooling computers and radars.

"We are converting waste heat to electricity in an efficient, simple way by using sound," says Orest Symko, a University of Utah physics professor who leads the effort. "It is a new source of renewable energy from waste heat."

How cool is that? Probably not cool at all. It's hot. At least it has to be hot to work.

It's got me wondering, though. How hot does it have to be? If we can turn heat into sound, and sound into energy, couldn't we use this to capture ambient heat in hotter climates, like the one I live in? I'd love to be able to help power my AC with the very heat I'm trying to fend off.

What about using sound waves directly? If we could create a way to capture ambient sound waves in the middle of a noisy city street or construction zone, to create a static standing wave, couldn't we take advantage of the very noise we create to help power the technologies we create it with?

I'm sure there are all kinds of "it won't work yet because . . ." excuses, and I'm certainly not proposing it will be some kind of perpetual motion device. I feel the same way about home based solar panels and windmills. They aren't (currently) complete energy replacement solutions. Let's think about this, though. With enough small "streams" of electricity in place, even if they aren't continuous, won't they still contribute, reducing our overall reliance on fossil fuels, and other climate damaging power production methods?

Now that's hot.