Wriggling Heat Sinks

YourHero writes "Purdue researchers have come up with a new way to cool chips, in about 2 years. Just build a bunch of little piezoelectric fans (the waving kind, not the spinning kind). Since they don't spin, no bearings, less self-generated heat. Since they don't have magnets, no electromagnetic noise problems. And, of course, super-efficient. A press release and abstract for your reading pleasure. Formal presentation at THERMES 2002 Jan 15th."

electomagnetic noise....

[Anonymous Coward]

the fact that there are no magnets has nothing to do with the electromagnetic noise..

Still need Whirly-Birds

[miracle69]

The innovative fans will not replace conventional fans. Instead, they will be used to enhance the cooling now provided by conventional fans and passive design features, such as heat-dissipating fins.

Oops. Looks like the editor didn't read the article....

Does this surprise anyone?

Piezoelectric fans are already available

[Harumuka]

At least from Piezo Systems Inc. [piezo.com] in Cambridge, MA. Their specs are worth reproducing:

• Input Voltage: 115VAC, 60 Hz
  
• Capacitance: 15 nF
  
• Power Consumption: 30 mW
  
• Volume Flow Rate: 2 CFM, (0.9 l/s)
  
• Peak Air Velocity: 400 FPM, (2.0 m/s)
  
• Weight: 2.8 grams
  
• Mounting: #2-56 clr. holes, 2 places
  
• Temperature Range: -20 C to 70 C
  
• EMI/RFI: None
  

However, they're not cheap. Pricing starts at $149. Additionally there is a Piezoelectric Resonant Blade Element [piezo.com]. Interesting stuff. Hopefully mass production of piezoelectric fans will lower their price to the average customer range.

Piezo fans? Old hat.

[FFFish]

Here's a picture of an old-style piezo fan [piezo.com]

You used to be able to buy piezo fans for the old Mac Classic [acornworld.net] (read the list near the bottom of the page).

IOW, piezo fans have been around since the mid-to-late 80's. Now, yes, I'll admit that they weren't very efficient (as in, they didn't move a lot of air)... but the concept has been there for eons.

Re:Piezoelectric fans are already available

[Anonymous Coward]

Ouch. But, considering that you'd need 20 or so of those to replace a single conventional fan in flow rate, you'd be able to get their bulk prices. Then, they're only $49 each (or roughly $1000 per conventional fan).

Nothing New

[pcjunky]

I have had one of these fans cooling my sterio for years. I got mine as a sample while working for a crystal manufacurer in 1984. It makes VERY little noise but does not even begin to move enough air to cool a modern CPU. These new ones would have to be 10 times more powerful.

Re:Piezoelectric fans are already available

[Harumuka]

Ouch. But, considering that you'd need 20 or so of those to replace a single conventional fan in flow rate, you'd be able to get their bulk prices.

Not a bad estimate. Considering computer fans typically move 20-30 CFM, although high-end [coolerguys.com] fans which blow more than 50 CFM), you would need 10 to 15 piezoelectric fans to achieve equivalent volume air flow. In 5-24 quantites they cost $79, so that translates to $790 to $1185.

Of course, laptop manufacturers could buy in bulk (100+) easily at $39. $390 to $585 per fan, significantly less.

Yet, according to the article these are novelty fans. If it costs manufacturers $149 per novelty fan, I wonder what the "real" thing costs...

Answer: what is piezoelectric?

[Jucius Maximus]

For those who are unaware, piezoelectric crystals are items that will change shape under the application of an electric field and/or generate a potential difference (i.e. a voltage) when squeezed.

They're used in inkjet printers - they're in ink some cartridge when an electric field is applied to them and they change shape, forcing the ink out of the I also hear the they used them in the ipod for some sort of playlist control mechanism.