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

Re:Microwave Fridge

[Dog135]

Unfortunately, there's absolutely no way to move heat from anywhere to a warmer place.

Using the Peltier effect you can. By connecting a high conducting material and a low conducting material to a battery, the high conducting material becomes cold, without even getting hot. The heat transfers to the low conducting material regardless of the ambiant temprature.

http://www.its.caltech.edu/~jsnyder/thermoelectric s/history_page.htm
http://www.quasarelectronics.com/3066.htm

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:Peltier cooler?

[WindBourne]

My understanding is that they are doing an ultra thin coating rather than doing a gas. But you do have a point.

Of course, I do find it funny that we allow our homes to be built on radon sites, but would prevent Tritium from being used on watch dials. But that was a total knee jerk reaction.

From what I have heard, Boeing is getting ready to use them as is the military. In many ways they make a lot more sense as no mechanical parts. Pretty much means no future repairs or re-filling.

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

Re:I'm amazed B&J's still operates semi-autono

[StateOfTheUnion]

There was a contract that allowed them to remain somewhat autonomous . . . the ex-hippies (Ben and Jerry) would sell unless the buyer was contractually obligated to continue some the socially concious initiatives that they started.

And its probably good marketing . . . keeps the "socially concious" brand reputation.

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.

What's the problem GreenFreeze?

[danharan]

There already is a climate-friendly alternative, GreenFreeze. And the Europeans that have adopted this technology (despite the fact it was heavily pushed by GreenPeace) have a lot of experience making very energy-efficient appliances.

Unless they expect this to be cheaper/ more efficient, I can't understand why they would finance such research- except as publicity.

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:Thermoacoustic cooling for airconditioning?

[Lebo]

Could a thermoaccoustic AC unit be created? Sure, but it won't fix the problem of 3rd world AC. The electricity costs of a Thermoaccoustic AC unit would actualy be HIGHER then the costs for a conventional unit.

The issue here is not energy-efficency, it's abandoning ozone-depleateing refrigerants.

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.

Re:Question

[Theaetetus]

Speaking of kitchen efficiencies, Spider Robinson once had an essay about the incredible heating-cooling inefficiencies in any modern kitchen...

• Stoves that have doors that must be opened to see inside, and doors that open downwards letting heat escape. Could be better designed with larger, clearer windows and lighting inside, and doors that either open upwards (hinged at top) or have some shutter-type arrangement that would allow heat to stay inside the oven with less escape.
• Refridgerators that have freezers on top, doors that open horizontally, and create waste heat in the rest of the room. More efficient would be freezers that open upwards (like ice chests) or freezers on the bottom (let the heat rise up and keep the 'fridge' compartment warmer than the freezer), windows that let you see food so that you don't have to let the cold out while you look at the contents, and a way of harnessing the waste heat for use in the oven or dishwasher located right next to the fridge.
• Sinks without thermocouples, necessitating playing with the faucet to get the proper temperatures... A dial would be much faster and easier.

Etc.

-T

Refinement of Einstein and Szilard's design?

[Mark of THE CITY]

The story reminded me that Einstein and Szilard obtained patents on various thermoacoustic refrigerators.Is this a refinement of that?