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  • This is a work in process,

  • based on some comments that were made at TED two years ago

  • about the need for the storage of vaccine.

  • (Video): [On this planet

  • 1.6 billion people

  • don't have access to electricity

  • refrigeration

  • or stored fuels

  • this is a problem

  • it impacts:

  • the spread of disease

  • the storage of food and medicine

  • and the quality of life.

  • So here's the plan ... inexpensive refrigeration

  • that doesn't use electricity, propane, gas, kerosene or consumables

  • time for some thermodynamics

  • And the story of the Intermittent Absorption Refrigerator]

  • Adam Grosser: So 29 years ago, I had this thermo teacher

  • who talked about absorption and refrigeration, one of those things

  • that stuck in my head, a lot like the Stirling engine:

  • it was cool, but you didn't know what to do with it.

  • It was invented in 1858, by this guy Ferdinand Carré,

  • but he couldn't actually build anything with it

  • because of the tools at the time.

  • This crazy Canadian named Powel Crosley commercialized this thing

  • called the IcyBall, in 1928.

  • It was a really neat idea, and I'll get to why it didn't work,

  • but here's how it works.

  • There's two spheres and they're separated in distance.

  • One has a working fluid, water and ammonia,

  • and the other is a condenser.

  • You heat up one side, the hot side.

  • The ammonia evaporates and it recondenses in the other side.

  • You let it cool to room temperature,

  • and then, as the ammonia reevaporates and combines with the water

  • back on the erstwhile hot side,

  • it creates a powerful cooling effect.

  • So it was a great idea that didn't work at all.

  • They blew up.

  • (Laughter)

  • Because you're using ammonia, you get hugely high pressures

  • if you heated them wrong;

  • it topped 400 psi.

  • The ammonia was toxic, it sprayed everywhere.

  • But it was kind of an interesting thought.

  • So the great thing about 2006,

  • there's a lot of really great computational work you can do.

  • So we got the whole thermodynamics department at Stanford involved --

  • a lot of computational fluid dynamics.

  • We proved that most of the ammonia refrigeration tables are wrong.

  • We found some nontoxic refrigerants

  • that worked at very low vapor pressures.

  • We brought in a team from the UK --

  • a lot of great refrigeration people, it turns out, in the UK --

  • and built a test rig, and proved that, in fact,

  • we could make a low-pressure, nontoxic refrigerator.

  • So this is the way it works.

  • You put it on a cooking fire.

  • Most people have cooking fires in the world,

  • whether it's camel dung or wood.

  • It heats up for about 30 minutes, cools for an hour.

  • You put it into a container and it will refrigerate for 24 hours.

  • It looks like this.

  • This is the fifth prototype, it's not quite done.

  • It weighs about eight pounds, and this is the way it works.

  • You put it into a 15-liter vessel, about three gallons,

  • and it'll cool it down to just above freezing --

  • three degrees above freezing --

  • for 24 hours in a 30 degree C environment.

  • It's really cheap.

  • We think we can build these in high volumes for about 25 dollars,

  • in low volumes for about 40 dollars.

  • And we think we can make refrigeration something that everybody can have.

  • Thank you.

  • (Applause)

This is a work in process,

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B1 US TED ammonia thermodynamics absorption computational refrigerator

【TED】Adam Grosser: A mobile fridge for vaccines (Adam Grosser: A mobile fridge for vaccines)

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    Zenn posted on 2018/01/18
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