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Refrigerators To Cool With Sound (Cool!)
T-Kir writes "A very interesting report from the BBC where researchers at Penn State University are developing a prototype fridge that cools using metal plates and sound waves. If successful, this technology would help remove the dependance on gases that contribute to global warming. Talk about Cool!"
Check out their article here. Unfortunately, no mention of peoples' hair igniting.
The article specifically mentions that the sound intensity necessary can only be generated in a super-compressed gas. The sound wouldn't be audible to you at all. Or to your dog, for that matter. It would only exist inside the compression tube.
"Times have not become more violent. They have just become more televised."
-Marilyn Manson
Except the dB scale is logarithmic.
+3 dB = 2 x as loud
+10 dB = 10 x as loud
53 = 10 + 10 + 10 + 10 + 10 + 3 = 10*10*10*10*10*2 times as loud = 200000 times as loud. So actual its much more than "tens of thousands"
A small team of 10 or so in conjunction with Lawrence Livermore National Laboratory built a thermo-acoustic refridgerator. It didn't work to well but it sure did make a hell of alot of noise. :)
Our most successful aspect of the project was the prototyping of the stack. We discovered that a form of carbon areogel had some very cool properties that made isolating the heat exchanges easy. To test the new stack we created a "hooter-tube" (or holfer tube) which is the opposite of the refridgerator. We created a difference in temeperature to generate sound. We dipped one end of the tube in liqued nitrogen and then heated the other end with a blow dryer. It was a blast to play with becuase it was about the size of a light saber and becuase the open end was the cold end the air around the tip would condense and allow you to "see" the sound wave (well, a quarter of it anyway).
here are some photos and other stuff:
photo of hooter tube
photo of working refridgerator (very similar to ours)
Navy page with lots of info
BUNNY OF DEATH!
This research made some noise (ha!) about ten years ago. A company called Macrosonix holds the patents. Even NPR has covered this in the past ten years.
The best explanation of the technology I've seen is in "Fluid Power Journal."