Thermoacoustic Cooler Means Green-Friendly Icecream

MuddyRiverDoc writes "National Public Radio aired a story describing ice cream manufacturer Ben & Jerry's sponsored development of a thermoacoustic refrigeration technology, which uses helium gas subjected to ultra-loud 173 db sound to chill an ice cream cooler. The NPR interview and pictures of the Penn State researchers who did the development is available. There is also a brief description of the technique at the Penn State Live site and at the BBC, and an over-cute Ben & Jerry's broadband presentation, Sounds Cool!, that does however provide a useful diagram. Thermoacoustic refrigeration has been a focus of research for more than a decade at Purdue and elsewhere, and has reportedly flown on the Space Shuttle, but this prototype is reportedly the first that demonstrates the size, efficiency, and quiet operation that promises successful commercial introduction. Cool Sound Industries, Inc. is reportedly exclusively licensed for this thermoacoustic technology."

Comments

Microwave Fridge

[tindur]

I really miss a microwave fridge in my kitchen

Re:Microwave Fridge

[kaos.geo]

Some 8 years ago, I suggested a "microwave fridge"
to a friend, he dismissed it as impossible... but his mother who happened to be there (and also happens to be a major Physics major) liked the idea and after some years of occassional debate between her and her college professor-type friends, they phoned me to tell me that sound waves would do the trick... :P
At least now I know I wasnt so crazy after all! :P

Peltier cooler?

[beldraen]

Out of curiosity, is there a reason why peltier coolers haven't been more main stream? I even have a small cooler that uses one, but it seems the idea of making it into larger appliances is something not which of thought.

Re:Same Energy as Freon Systems

[Fian]

There is another disadvantage - Helium is a finite resource (excluding fusion). A lot of our current supply of helium is collected almost as a by-product of natural gas mining. When the supply runs out, which is anticipated to happen with a few decades, there won't be any liquid helium for super cooling or *gasp* for your party balloons - let alone to chill your groceries

I heard that

[N8F8]

A class I was taking last semester was being taught by a retired NASA program manager who mentioned the helium scarcity. Most of the world's helium is "mined" in Texas, so if this were handled correctly it could lead to quite the litte technology monopoly. OTOH, if helium were to become more scarce on earth I pretty sure someone would find an alternative source.

Ice cream plants are already enviromentally safe

[chrisatslashdot]

This technology may be great for retail coolers and the like but virtually all ice cream plants already use an environmentally safe refrigerant. Anhydrous ammonia is the refrigerant of choice for industrial applications.

• It causes no ozone depletion
• It does not contribute to global warming
• It has heat transfer characteristics 1.6 to 4 times that of HFCs and CFCs
• It requires 1.22 HP per ton of refrigeration (versus 1.27 for R134a and 1.25 for R22 this can be important when you have 10,000 HP engine rooms)
• It cost $0.25/lb (versus $3.40 to $25.00 for HFCs and CFCs) Important when you have hundreds of thousands of pounds of charge.
• It is lighter than air (unlike HFCs and CFCs) so releases typically float away
• It has a narrow window of explosive concentration that is difficult to achive LEL:16% UEL:25%(its is hard to make it go boom)
• It is a naturally occuring chemical. Your body make ammonia.
• Its pungent odor is 'self-alarming'. You will leave an atmosphere of ammonia long before concentration levels reach dangerous limits.

The reason you don't have ammonia in your car and home is that exposure to the chemical in concentrations above 300ppm poses health risk. 30 minutes of exposure above 1720ppm can cause death and 5,000ppm is rapidly fatal. It should never be used in a run-to-failure, zero maintenance system like your kitchen fridge or AC unit.

Re:Ice cream plants are already enviromentally saf

[jafiwam]

Themoacoustic coolers can probably be produced with a much higher mean time between failure as well. Fewer moving parts. I assume they could make a long-life speaker cone and make it replacable with a "slide out, slide in, recharge gas" type fix.

The end result is fewer fridges go to landfills beause they broke.

Even if the average lifetime of the fridge can be raised by a few percent, that's significant reduction in appliance-garbage.