Thermoacoustics "sounds cool"

As the name implies, thermoacoustics studies the interplay between heat and sound. My first exposure to the topic was Sondhauss oscillations, where hot glass starts “singing” sine waves.

Standard refrigeration works by vapour compression… What is a sound wave, if not a fluctuating pressure wave? To shorten a long ramble into one, potentially confusing, statement; If you can get a sound wave bouncing back and forth inside a tube (filled with helium at 17 bar), with nodes in the waveform interfering, and heat exchangers placed strategically at high and low pressure nodes, you can achieve single stage cryogenic cooling, with only one moving part, aside from the “working fluid”. I know that’s going to be hard to read, but I’m lazy, trying to be concise, and there are better resources for understanding how it works than something I haven’t typed yet anyway, including the sales brochure I plan on linking to.

The world leaders in this tech are a company called “QDrive”, along with Los Alamos labs. I was looking into thermoacoustic cryocoolers well over a decade ago for liquifying oxygen, and decided it wasn’t economically viable for me at that point, but I’ve kept an eye on the company since. They and their parent companies keep being bought up by bigger and bigger fish, and they are currently in the belly of the military contractor RIX Industries.

So yeah, who’s interested in efficient, single stage cryogenic cooling?

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Sounds :grin:Great
What’s the price tag ?

I don’t know, it’s been a long time since I got a quote from them.

It would be nice to see a cooling capacity sheet for closer to our relevant temperature range. Hard to make judgment based on capacities at 77K. At these deep temperatures more energy inefficiency is considered acceptable so I don’t even know how to make an apples to apples comparison on this one.

They were still owned by CFIC, back when I first got on their mailing list. It was 2005 or so, and there are cheaper ways to store oxygen, so I have no clue about current pricing. I went looking for the website I remember, and they’re no longer on Chart Industries websites. I can look through my emails for when they got taken over by RIX, and get the email of a current sales rep if anyone wants…

What can we use to DIY one of these? What’s the little symbol mean after the 1 and before the Hertz on power requirements?

I don’t know about the DIY thing, but perhaps start by searching alibaba for pulse-tube refrigeration knockoffs? As far as that symbol, it’s “Phi”, and the one denotes that it runs on single phase AC.

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Plug and play coldtrap :smirk:

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