It's been getting really hot up in the Northern Hemisphere lately, so here's a way to combat the heat by making a cooler that stays cool. Just add water!
This project is based on the recent invention of Emily Cummins, originally designed for impoverished families in Africa to keep meat and milk from going bad. The beauty of the cooler is its simplicity. It can be made from scrap materials that can be found in almost any home, sometimes in the trash. The Evaporation Fridge consists of an inner and outer tube, with a wet material in between the two layers. Perishable items are kept in the inner tube in a sealed container. As the water in the wet material evaporates, it removes heat from the inner tube and lowers the temperature. The whole process can be compared to the human perspiration system. Think of the fridge as a cooler that sweats, except less gross.
UPDATE: Check out the new version here:
http://www.instructables.com/id/Dew-Bucket-Evaporative-Drink-Cooler/
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Signing UpStep 1: Tools and Materials
I found all of my materials in my garage. If you can't find something, feel free to substitute similar object. My materials are as follows:
1 empty paint bucket
1 empty lantern propane tank(small)
2 plastic tank caps(from full or empty propane tanks)
4-6 rags/washcloths(anything that holds water: sand, sponge, wool, ShamWOW)
2 mesh gutter covers
1 can of spray paint
sandpaper
steel wool
The tools that I used are also very common:
drill press
1" hole saw drill bit
small drill bit
hacksaw with blade for metal
tin snips
hot glue gun
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I just checked Coleman's site and it says that the idea didn't catch on so they aren't including the Green Key with their cylinders anymore. That doesn't mean a person couldn't locate one or two if they wanted to try this project without fear of fire/explosion.
Link: http://www.coleman.com/coleman/recycle/cylinder_dis.asp
As an alternative method of "safeing" a propane can before cutting it, someone here at Instructables suggested filling it with water to displace and absorb any traces of gas. Maybe the author or someone else will recognize which -ible talks about using water to make an empty propane tank safe for cutting.
Yeah I'll say evaporative cooling has been around since Egyptian times, even thin sheets of ice were made at night using the method! (Sorry I have no URL reference for that factoid, but I did read it in a book many years ago.)
Nice -ible, keep going with these. :)
DIY-Guy
http://www.instructables.com/id/Evaporative-Cooler-1/
I think it could spur some ideas with all the brilliant people on this site
http://www.instructables.com/id/Portable-room-cooler/
A filling of damp sand or crushed charcoal works very well for a filling between the two containers. You could also use sawdust, moss, straw or leaves, as long as you have water to dampen them. Using a porous container for the outer layer increases the cooling (for example a large unglazed flower pot) or sink your container into the ground with pebbles around it and keep them damp. In the old days, people often dug out a hole and put a wooden keg into the ground with a wooden box sitting on top. They back filled around the keg with small stones, wet them down and filled in around the barrel with dirt, which was mounded up around the box to allow rain to run away from the keg. The box was the 'lid' of this under ground cooler. A stick was fastened to the box and containers of food were tied to the stick and hung in the keg below. This kept food from spoiling for several days.
Just a little note of interest: In the middle east they made ice by pouring water in shallow trays and placing them where the wind would blow over them. The water would develop a thin layer of ice which would be collected before sunup and stored in tall jars, kept in a cool corner. Their houses were cooled naturally by woven mats hung across the small windows on the windward side of the house. These mats were kept damp by ladeling water across them. Natural swamp coolers!
Then the inner liner. If the food is put in chilled plus some ice blocks would it be best to use an insulated inner to keep the heat out or would that be counterproductive in that colling would not be efficient?
Evaporative cooling have been used in developing nations for some time - Cummins has only changed the materials, as the originals used two clay pots, with water-soaked sand in between. The water evaporated straight through the porous clay.
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Having said that, this is a good Make. Well done.