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This is a work in process,
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based on some comments that were made at TED two years ago
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about the need for the storage of vaccine.
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(Video): [On this planet
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1.6 billion people
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don't have access to electricity
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refrigeration
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or stored fuels
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this is a problem
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it impacts:
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the spread of disease
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the storage of food and medicine
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and the quality of life.
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So here's the plan ... inexpensive refrigeration
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that doesn't use electricity, propane, gas, kerosene or consumables
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time for some thermodynamics
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And the story of the Intermittent Absorption Refrigerator]
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Adam Grosser: So 29 years ago, I had this thermo teacher
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who talked about absorption and refrigeration, one of those things
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that stuck in my head, a lot like the Stirling engine:
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it was cool, but you didn't know what to do with it.
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It was invented in 1858, by this guy Ferdinand Carré,
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but he couldn't actually build anything with it
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because of the tools at the time.
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This crazy Canadian named Powel Crosley commercialized this thing
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called the IcyBall, in 1928.
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It was a really neat idea, and I'll get to why it didn't work,
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but here's how it works.
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There's two spheres and they're separated in distance.
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One has a working fluid, water and ammonia,
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and the other is a condenser.
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You heat up one side, the hot side.
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The ammonia evaporates and it recondenses in the other side.
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You let it cool to room temperature,
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and then, as the ammonia reevaporates and combines with the water
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back on the erstwhile hot side,
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it creates a powerful cooling effect.
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So it was a great idea that didn't work at all.
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They blew up.
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(Laughter)
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Because you're using ammonia, you get hugely high pressures
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if you heated them wrong;
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it topped 400 psi.
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The ammonia was toxic, it sprayed everywhere.
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But it was kind of an interesting thought.
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So the great thing about 2006,
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there's a lot of really great computational work you can do.
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So we got the whole thermodynamics department at Stanford involved --
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a lot of computational fluid dynamics.
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We proved that most of the ammonia refrigeration tables are wrong.
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We found some nontoxic refrigerants
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that worked at very low vapor pressures.
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We brought in a team from the UK --
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a lot of great refrigeration people, it turns out, in the UK --
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and built a test rig, and proved that, in fact,
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we could make a low-pressure, nontoxic refrigerator.
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So this is the way it works.
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You put it on a cooking fire.
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Most people have cooking fires in the world,
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whether it's camel dung or wood.
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It heats up for about 30 minutes, cools for an hour.
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You put it into a container and it will refrigerate for 24 hours.
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It looks like this.
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This is the fifth prototype, it's not quite done.
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It weighs about eight pounds, and this is the way it works.
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You put it into a 15-liter vessel, about three gallons,
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and it'll cool it down to just above freezing --
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three degrees above freezing --
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for 24 hours in a 30 degree C environment.
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It's really cheap.
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We think we can build these in high volumes for about 25 dollars,
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in low volumes for about 40 dollars.
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And we think we can make refrigeration something that everybody can have.
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Thank you.
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(Applause)