Researchers at General Electric has developed a new air-cooling system based on human lungs that's half the size of conventional computer fans but just as effective at keeping things chilly. GE cooler You just purse your lips and... (click to enlarge) The prototype uses 40mm by 40mm thin metal plates which are bonded to …
"We tested the devices in Mil-STD-810G sand and dust testing environment. They were blasted with really fine grain dust from many different angles," he said. "After four days we had all six devices still working with no problems."
Wow, 4 whole days! :)
I think most tech folks will note that it's not sandy dust that they find in computers but that nasty, sticky, skin-based grey stuff. That's where the testing needs to be.
Re: Test Cycle
That's four days consuming as much sand/dust as a device could reasonably inhale in several years I'd reckon.
But yes - the sticky stuff does require other testing.
sticky stuff does require other testing
Re: not sandy dust
Fluff - where's the military standard for that?
Anyone remember the piezo fans for the early Macs?
And I'm thinking that 115Hz would be really irritating.
I wonder if it makes noise?
115 Hz is in the range of human hearing, but it doesn't necessarily mean the noise is audible. If it sounds like breathing, I would if it be similar to listening to a hummingbird breathe?
GE not visiting the electronics store much
They're called "synthetic jet" fans and they're already on the market.
Hello, thank you for your comment. Synthetic jets is a family name for devices with a single opening and an oscilating actuator. The GE #DCJ is unique as the dual osciliating plates cancels vibration and the wide slot openening is designed to entrain additional airflow creating a net air flow. It is able to do so in a unique 1mm height and expel air in a planar fashion. I hope this helps.
Thank you for that information Peter. I'm wondering about a couple of points as a result:
With an oscillation frequency of about 150Hz, the wavelength in air will be about 2 metres so any vibration cancellation effects would not be due to air-wave interference at a distance from the source. (I'm not an acoustics expert by any means so I hope anyone with knowledge of this subject will join in....). Do the oscillating plates vibrate in the same direction (one goes into the 'fan' cavity as the other goes out) or do they vibrate in opposite directions (both go in/out at the same time) thus expanding the cavity and then compressing it? Given that a flat plate is vibrating at 150Hz and given the complexities of vibration and sound propagation inside a PC or laptop, I'm surprised that a nearby plate (on the other 'side') is able to cancel sound waves launched by the first plate.
Is the frequency of operation related to the mechanical resonance characteristics of the fan plate assembly, or is it related to requirements due to the characteristics of air flow through the fan?
It seems to be a fascinating and useful development and I look forward to large and silent PCs and laptops one day.
He could tell you but then you'd have have to patent your brain and be owned by him. ;)
About the acoustic coupling - if the plates are << than the wavelengh of 150 hz waves, they will not be an efficient source of sound waves (this is why woofers are large). Also, if the plates move in opposite directions,
a rarefaction produced by one will overlap with a compression produced by the other. I bet it would actually be pretty quiet.
Or maybe hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm.
This would depend how good/bad its isolation/coupling to the surroundings are; low frequency hum is notoriously difficult to keep out of places where you don't want it. Perhaps a three-layer device working in anti-phase to itself?
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