Thermoacoustic Refrigeration

[bags]

hi friends,
I wanted to know about the Thermoacoustic Refrigeration.Can u please submit any links or explanation about the topic.Looking forward to your replies.

 

[Danger]

Sorry, bags, but I can't help you. I've never even heard of that before. I'm just weighing in so you don't think that you're being ignored. Others are looking for your answers.

 

[Artman]

Here is an article with a decent basic description of the process.

http://www.ehponline.org/docs/1994/102-9/innovations.html" Quote below from the article:

How does it work? First, customized loudspeakers are attached to cylindrical chambers filled with inert, pressurized gases such as xenon and helium. At the opposite end of the tubes are tightly wound "jelly rolls" made of plastic film glued to ordinary fishing line. When the loudspeakers blast sound at 180 decibels, an acoustic wave resonates in the chambers. As gas molecules begin dancing frantically in response to the sound, they are compressed and heated, with temperatures reaching a peak at the thickest point of the acoustic wave. That's where the superhot gas molecules crash into the plastic rolls. After transferring their heat to the stack, the sound wave causes the molecules to expand and cool. "Each one of these oscillating molecules acts as a member of a 'bucket brigade,' carrying heat toward the source of the sound," says Garrett. Cold temperatures can then be tapped for chilling refrigerators, bedrooms, cars, or electronic components on satellites and inside computers, according to Garrett. Someday, he says, turning up the air-conditioner could be accomplished by adjusting a volume-control knob.

 

[LuZ]

I'm trying to build up a knowledge base on this here

http://www.mecheng.adelaide.edu.au/anvc/thermoacoustics/

 

[FredGarvin]

180 dB? Wholly molley. Forget worrying about fan noise from that fridge.

 

[LuZ]

180 dB? Wholly molley. Forget worrying about fan noise from that fridge.

That's the internal sound pressure level. You'll find that the 'noise' amplitude inside a typical thermoacoustic refrigerator is in general, similar or less than that of a typical vapour compression system, so the expectation in external noise levels should be similar.

A system I built myself that achieved an max internal SPL of 176dB operating at ~105Hz was found to emit a sound power level equivalent to 51dB(A) at 1 metre.

 

[FredGarvin]

What's the main cause for the attenuation? From 180 to 51 dB is pretty substantial.

 

[LuZ]

What's the main cause for the attenuation? From 180 to 51 dB is pretty substantial.

It is: believe it

Provided that the structure is not driven at a resonant frequency, it's due to the high structural impedance to the operating frequency, and poor re-radiation of vibration at the external surface. Also, it's 176dB to 51dB(A): the 'A' weighting is also a factor here.

 

[FredGarvin]

So is the acoustic source is a single frequency source? I guess that would make it easier to tailor the enclosure for those purposes. Pardon the pun, but very cool.

 

[LuZ]

So is the acoustic source is a single frequency source? I guess that would make it easier to tailor the enclosure for those purposes. Pardon the pun, but very cool.

The interior is largely featureless so the operating mode is typically of very http://en.wikipedia.org/wiki/Q_factor" (low damping). There are of course harmonics associated with the operating frequency, but are usually of insignificant level.

 

[Pat M]

Can anyone supply some details abount this type of cooling. Sounds interesting.
Thanks
Pat M

 

[LuZ]

Can anyone supply some details abount this type of cooling. Sounds interesting.
Thanks
Pat M

I'm going to blatantly refer to the links I've put together here:

http://www.mecheng.adelaide.edu.au/anvc/thermoacoustics/index.php?option=com_weblinks&Itemid=23

 

[asproegypt1]

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[pranj5]

Well, can anybody give me a comparative analysis of thermoacoustic compressors and conventional compressors regarding energy consumption and how much the thermoacoustic compress can compress gas/vapor i.e. upto which pressure level (in bars).