Refrigeration without electricity 4

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1. 

   Biodiversivist Posted 1:24 am
   24 Jun 2008

   SummaryAfter heating this thermos sized device in an open flame (fueled by any combustible source) and letting it cool for an hour you can put it in any enclosed 3 gallon container and it will keep the interior space just above freezing, (assuming a 30 deg C outside temp) for about 24 hours. They hope to mass produce them for about $25 to $40.
   The advantage it has over other flame powered refrigerators is that you don't need propane or kerosene to run it and it will cost far less. All you need is a cook fire.
   Engineering being the art of compromise, I can see a disadvantage in that you will have to build a fire to heat this device up every 24 hours to keep food cool. There is no free lunch. It will consume cooking fuel and because it is labor intensive, it will add to the time constraints and physical energy drain on a given villager who already expends a lot of time and energy working in fields, collecting water and fuel.
   I wonder if anyone has come up with a manually powered compressor fridge yet?
   Here is a diagram explaining how a the single pressure absorption fridge commonly found in RVs works. A propane flame is applied to the tube in the lower right corner where the baffle is located. To run this type of fridge a village would have to have a fairly reliable source of propane or kerosene.
   
   In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

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2. 

   amazingdrx Posted 1:31 am
   24 Jun 2008

   Cool!But of course many of us would prefer the heating part be done with a solar oven.  Then you could sterilize water and cook with the solar oven while the fridge was being recharged.  The solar oven, a simple fold out device could be provided with the cooling device.
   Anyway, great work!  Finally a big shot conference focuses on a simple effective solution.  More of this is needed.
   (You notice how he got in a plug for think tank supercomputing?  As if that was the key, hehey)
   
   http://amazngdrx.blogharbor.com/blog

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3. 

   amazingdrx Posted 1:42 am
   24 Jun 2008

   Tin canA number 10 tin can with dung or kindling in it could substitute for the gas flame in your example bio-d.  Or a solar oven could concentrate heat on the (normally) gas heated coils. Or biogas could be generated from biomass and manure to power the flame.  Same result.
   The beauty of the regular old gas fridge, converted to dung/biogas/solar, would be that you don't need to time the whole thing.  A regular gas fridge can make ice to store the cold temps until the sun shines again or someone puts some fuel in the burner.  Storing cold is difficult without the water to ice phase change.
   In sunny climes where refrigeration is vital plenty of solar power exists to power it.
   
   http://amazngdrx.blogharbor.com/blog

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4. 

   Ron Steenblik Posted 3:09 am
   24 Jun 2008

   Keeping hot things hot, and cold things coldKind of reminds me of the old story about the kid and the thermos.
   On his first day at school, Ronnie goes off to the cafeteria. Next to him, David, one of his clasmates, opens his lunch box and pulls out a thermos. Ronnie asks, "What's that?"
   David answers, "It's a thermos. It keeps hot things hot, and cold things cold."
   When Ronnie returns home, he asks his parents whether they have a thermos and whether he can bring it to school. "Of course you can, Ronnie", they say. His Dad pulls one down from the shelf and hands it to him.
   The next day Ronnie goes off to school, proud to have such a wonderful object.
   David sees Ronnie's thermos and asks, "What's in it?"
   "Soup and ice cream!", answers Ronnie.
   
   These are only my personal opinions.

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