A Refrigerator that Runs Without Electricity

[Serpo]

(http://www.permacultureusa.org/2008/08/11/a-refrigerator-that-runs-without-electricity/)

Community Projects (http://www.permacultureusa.org/category/permaculture-projects/community-projects/), Processing & Food Preservation (http://www.permacultureusa.org/category/food-food-support-systems/processing-food-preservation/) — by Craig Mackintosh (http://www.permacultureusa.org/author/Craig%20Mackintosh) August 11, 2008

http://www.permacultureusa.org/images/mohammed_bah_abba.jpgSometimes there are simple solutions to universal needs that don’t require coal fired electricity, fossil fuels, or even solar panels or wind turbines.
Around a third of the world’s population have no access to electricity. If you’re like me, you’ve spent your entire life being able to plug in. Do we ever give a thought to what life would be like if the various appliances we’ve come to rely on were to suddenly stop working? One of the most energy guzzling appliances in our carbon footprint portfolio is the refrigerator. But, unplug it, and the quality of your life will suddenly deteriorate. Take that thought, and imagine living in a hot dry country in Africa, without electricity, where food quickly wilts and rots in the sun, aided by onslaughts of flies.
One modern day genius, mindful of this basic need to preserve food, has solved the problem for many. Mohammed Bah Abba, a Nigerian teacher, invented the ‘device’ — a refrigerator that doesn’t require electricity!

http://www.permacultureusa.org/images/pot-in-pot_refrigerator.jpgFrom a family of pot-makers, Mohammed has made ingeniously simple use of the laws of thermodynamics to create the pot-in-pot refrigerator, called a Zeer in Arabic.
Here’s how it works.
You take two earthen pots, both being the same shape but different sizes, and put one within the other. Then, fill the space between the two pots with sand before pouring water into the same cavity to make the sand wet. Then, place food items into the inner pot, and cover with a lid or damp cloth. You only need to ensure the pot-in-pot refrigerator is kept in a dry, well-ventilated space; the laws of thermodynamics does the rest. As the moisture in the sand evaporates, it draws heat away from the inner pot, cooling its contents. The only maintenance required is the addition of more water, around twice a day.
0digg

To give an idea of its performance, spinach that would normally wilt within hours in the African heat will last around twelve days in the pot, and items like tomatoes and peppers that normally struggle to survive a few days, now last three weeks. Aubergines (eggplants) get a life extension from just a few days to almost a month.
Inventing the refrigerator in 1995, Mohammed distributed thousands around Nigerian communities during the late 1990s (initially for free to get the word out, then later at just production-cost price), and subsequently won the Rolex Award for Enterprise (http://www.rolexawards.com/special-feature/inventions/abba.html) in the year 2000. It has improved the lives and health of thousands. Less work can translate into more education for children, and small farmers who were before losing large proportions of their harvest (http://www.scienceinafrica.co.za/2004/september/refrigeration.htm) are now able to earn a better income. Another knock-on benefit is improved health due to better preservation of vitamins, as well as a reduction in health problems like dysentery due to the separation of food and flies.
It seems that not all the answers to life’s needs have to come with a plug and instruction book.
http://www.permacultureusa.org/2008/8/11/a-refrigerator-that-runs-without-electricity/

[vacuum]

Great idea and something to keep in mind. I'm kind of interested in the basic details which they could have published. Like, what are the size of the pots? How much sand (inches) separate them? Is there a hole in the bottom of the large pot to keep water from pooling in the sand?

Something to note here is that this type of thing will only work in arid environments. Humidity will impede the evaporation of water. High outdoor temps may also help somewhat.

[mightymanx]

And we give nobel piece prizes to people that manage 2 on going wars and start a third.

(insert facepalm here)

[beefsteak]

For western preppers, here are additional mods:

Add a dripper fitting to a tubing and place atop the sand surround.

Connect same to small, desktop water feature pump disassembled and re-purposed for this 'frig...(these are now cluttering garage- yard- and thrifty- displays of goods on the cheap (50c to a $1)} ...Voila, a minimal maintenance evaporator.

The drippers come in various "gpms" so one could match H2O additions quite nicely to the size of the 2 pot 'frig and the amount of sand layer with very brief experimentation.

Ordinary drip irrigation tubing could be perf'd and said tubing snaked around the inner pot, as both are buried within the sand envelop.

The more sand, the more evap...the more drips. If one wanted a recir unit, then place a hole in the bottom of the "outside pot" and let it drip back --filtered, of course--into the water source into which the desktop fountain pump is depositing the drips.

Attach to a small solar panel continuously topping off a 12v DC battery, and this is another American Prepper version.
It's quite easy to splice in a couple of banana clips into the solar pump wiring so that it can operate both day and night.

These solar powered pumps from China and sold on eBay *under $20-- (as well as formerly available thru Harbor Freight) can reeeeeally move some water. We love'em around here...have 5 of them now. (ebay seller ID: planemodel-a (http://myworld.ebay.com/planemodel-a/?_trksid=p4340.l2559) ( Feedback Score Of 12286 (http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback&iid=140571045256&userid=planemodel-a&ssPageName=VIP:feedback&ftab=FeedbackAsSeller&_trksid=p4340.l2560)http://p.ebaystatic.com/aw/pics/icon/iconShootYllw_25x25.gif) My newest ones arrived in about 10 days from China. In perfect order and working condition.

Suggest purchasing a thumb-twist drip irritation fitting into the tubing to help regulate the speed of the pumped water the 4"x4" solar panel can put out through the dripper end.

I'd start with a 1" sand cushion between pots. Evaporation requires "surface area" to maximize evaporative effect.


beefsteak

[mick silver]

beefsteak what the temp on something like you just did ?

[Dogman]

http://en.wikipedia.org/wiki/Pot-in-pot_refrigerator

And this.

Methods of Alternative Refrigeration

http://www.provident-living-today.com/images/Iced-Cherries.jpg

Passive Cooling

Here are three methods of alternative refrigeration you can use without electricity. Your best success will come using a combination of all three passive cooling methods. Having a way to refrigerate your food and “chill out” when the power goes out could be one thing to help ease the stress during a crisis.
Solution 1: Evaporative Cooler Fridge

http://www.provident-living-today.com/images/Evaporative-Refrigerator.jpg

Supplies needed:

A shelf unit
Burlap bags
Clamps or clothespins
Large pan for water (if needed)
A cheap PVC shelf unit from you local hardware store works well. It’s lightweight and inexpensive.

Assembling Instructions:


Assemble shelf with the top shelf inverted (shown in picture) to use as a built-in tray for water.
Cut burlap to fit around shelf. I recommend doing this ahead of time in case you need to sew pieces together.
Soak burlap in water and place around shelf as shown using the clamps or clothespins to hold cloth in place.
Fill the top (or large pan/cookie sheet) with water.
Leave an extra amount of burlap folded over on the top to soak in the water.

As the water wicks down the burlap there's a cooling effect on the items placed inside on the shelf.Putting it in the shade is of course optimal and a slight breeze is helpful too.
One year when I was at a family reunion in Pinedale, AZ during the summer, we used this alternative refrigeration method to keep our things cool because there was a short supply of ice for coolers. It worked VERY well.


Solution 2: Zeer Pots

Supplies needed:

2 clay pots that are able to nest inside of each other (round pots work best). They need to be clay/earthenware and MUST be unglazed.
Sand-- enough to fill in the space between the 2 pots
A piece of burlap or thick blanket


http://www.provident-living-today.com/images/Zeer-Pots.jpg


Mohammed Bah Abba of northern Nigeria won a Rolex Award for his pot-in-pot invention. It is a refrigerator than runs without electricity. “A key reason for the pot-in-pot’s success is the lack of electricity in most of the northern rural communities, for without electricity there can be no refrigeration.” This alternative refrigeration method is being used in Third world countries to help fresh produce last longer.

Here's how it works.

You take a smaller pot and put it inside a larger pot. Fill the space in between the two pots with wet sand. Cover the pots with a wet cloth. When the water evaporates, it pulls the heat out with it. This simple alternative refrigeration unit uses basic laws of physics to keep the inner vessel cool.
To learn more about Mahammed’s Story and the physics of how this alternative refrigeration unit works go to Rolex Awards. (http://rolexawards.com/en/the-laureates/mohammedbahabba-the-project.jsp)

Solution 3: Radiant Fridge

http://www.provident-living-today.com/images/Solar-Cookit-Folded-Border.jpg http://www.provident-living-today.com/images/Solar-Cookit-Plain.jpg

Using a solar oven of all things!

This is a fabulous way to sometimes actually MAKE ice at night in the same item that you used during the day to cook your food! You can then use the ice to cool things during the day. The only problem with this option is that it requires you have to have a clear NIGHT to work.

Set it up like a solar oven. The same rules apply. Just put the jar or pan with a bag around it with the water inside. The air is concentrated into the container just like the sun is during the day. In the morning you have ice, or at the least you can put an item that needs to keep cool inside the pot so that the temperature can be colder during the night.

Two Examples Radiant Cooling

How to Use the Solar Funnel as a Refrigerator/CoolerHere’s an excerpt from the writing of Steven Jones, (http://www.solarcooking.org/plans/funnel.htm) a retired physics professor.

http://www.provident-living-today.com/images/Solar-Funnel-Cooker.jpg

“Funnel Cooker can be used - at night - as a refrigerator. Here is how this is done. The Solar Funnel Cooker is set-up just as you would during sun-light hours, with two exceptions:


The funnel is directed at the dark night sky. It should not "see" any buildings or even trees. (The thermal radiation from walls, trees, or even clouds will diminish the cooling effect.)
It helps to place 2 (two) bags around the jar instead of just one, with air spaces between the bags and between the inner bag and the jar. HDPE and ordinary polyethylene bags work well, since polyethylene is nearly transparent to infrared radiation, allowing it to escape into the "heat sink" of the dark sky.

During the day, the sun's rays are reflected onto the cooking vessel which becomes hot quickly. At night, heat from the vessel is radiated outward, towards empty space, which is very cold indeed (a "heat sink").

As a result, the cooking vessel now becomes a small refrigerator. We routinely achieve cooling of about 20º F (10º C) below ambient air temperature using this remarkably simple scheme.”
Using a Solar Oven as a Radiant Refrigerator at Night

http://www.provident-living-today.com/images/Radiant-Refridgerator.jpg

Richard McMahon of Western AustraliaHe used a box cooker to make ice. The “Uncooker” was placed in a location where it saw a maximum amount of sky and no trees or buildings. He was getting ice in the cooker even though the outside temperature was above freezing. During the summer months he was unable to make ice.

Later he built a radiant refrigerator. During the summer months the temperature inside the fridge would not rise above 16° C. Read More . . . (http://solarcooking.org/radiant-fridge.htm)

http://www.provident-living-today.com/Alternative-Refrigeration.html

[beefsteak]

beefsteak what the temp on something like you just did ?

mick silver, on the larger pot set-up, 45-48F pretty consistently.

[DMac]

Here is another method to make ice when you have no power:


Ice may be needed for many reasons. To help keep perishable items cold, bring down a fever of a sick person, cool you off in extreme heat of summer. But what do you do if there is no electricity and no machinery to make ice with? You can make ice with fertilizer and water!

Why it works: Ammonium nitrate (a chemical found in fertilizer)is a salt, which is made up of a 50/50 mixture of ammonium and nitrate nitrogen. When ammonium nitrate is mixed with equal parts water the ammonium nitrate dissolves into the water. The energy is absorbed from the water, which causes the temperature of the water to decrease and therefore freeze, creating ice.

Here is what you do: Fill a bucket with equal parts water and ammonium nitrate(fertilizer) place a smaller metal bowl (you can’t use plastic as it is an insulator) half filled with water in the bucket and wait. The bowl of water will freeze and you have clean ice

Make sure your storage items contain Ammonium Nitrate! You can buy it in small quantities at your local farm supply store.

[beefsteak]

Thanks for a terrific reply, DMac.

Happened to be watching the Jerico series here at our house, when this very method was demonstrated live on screen by the femme fatale, Ashley Scott, the blonde, who played Emily Sullivan.

I saved that particular section off onto my HD, but I never found the instructions for it. I hope others are as glad to see your detailed proportions of fertilizer to water.
That's been tougher than all git-out to me and the wife to find.

Don't expect the local farm supply store to look at anyone kindly who walks in asking for some Ammonium Nitrate, however. The Mara Bldg in OKC was blown-up by McVeigh using this particular fert.

It is my understanding that there are micro-printed particles in each mfg batch of Ammonium Nitrate, so as to help identify the source in case anyone gets any creative/destructive ideas, so be forewarned. At least they talked about it. Maybe the microprinting gig never happened, I do not know.

beefsteak

[Twisted Titan]

Bump.........

extremely timely info that should be revisited

[Gaillo]

Moved and stickied...

[solid]

mick silver, on the larger pot set-up, 45-48F pretty consistently.

That is amazing.

Beefsteak, can I pick your brain on some technical aspects? Does the outer pot need to be earthenware? I'm wondering, if you could use wood for the outer pot.

Basically, what I'd like to do is build one of these outside on deck near the helm, for cold drinks, etc. I'm thinking of using teak wood, because of teaks unique properties. Teak, is extremely rot resistant. Teak can remain submerged underwater for years without rotting actually. Also, teak weathers very well exposed to the elements of a harsh marine environment.

My idea is this, build a square solid teak box. line it with sand, and the inner box made of clay. Do you think I could substitute teak instead of clay for the outer layer? I'm thinking you want the outer box to breath some, to assist in the evaporation process. I think the teak would breath enough (I don't know) and also allow to keep the moisture in the sand trapped in side the box. I'm just speculating.

My other question is weight, how much does one of these things weigh in at?

This really sounds like a neat fun project, as well as having an emergency refrigerator and just a place to cool drinks outside.

[Dogman]

That is amazing.

Beefsteak, can I pick your brain on some technical aspects? Does the outer pot need to be earthenware? I'm wondering, if you could use wood for the outer pot.

Basically, what I'd like to do is build one of these outside on deck near the helm, for cold drinks, etc. I'm thinking of using teak wood, because of teaks unique properties. Teak, is extremely rot resistant. Teak can remain submerged underwater for years without rotting actually. Also, teak weathers very well exposed to the elements of a harsh marine environment.

My idea is this, build a square solid teak box. line it with sand, and the inner box made of clay. Do you think I could substitute teak instead of clay for the outer layer? I'm thinking you want the outer box to breath some, to assist in the evaporation process. I think the teak would breath enough (I don't know) and also allow to keep the moisture in the sand trapped in side the box. I'm just speculating.

My other question is weight, how much does one of these things weigh in at?

This really sounds like a neat fun project, as well as having an emergency refrigerator and just a place to cool drinks outside. The outer container needs to be porous so water can seep and evaporate too supply the cooling effect. Have you ever seen the old style canvas water canteens (no liner, just a canvas bag)? The water would seep out and keep the bag wet and as the water evaporated, it would cool the water inside. I have not seen one in years, but in hot and dry desert country, they work, the water would be cooler than the air temp.

Does teak breathe? The water in the sand needs to soak the teak so the water can evaporate off the outside. The inner box needs to be water tight so the food/drinks do not get wet. The wet sand does two things.

1. It is thermal mass that can transfer heat away from the inside pot/box. (Cold is the absence of heat)

2. It provides a reservoir of water and also helps transfer heat away from the inside.

Look at this link, and think about the principles explained.

http://en.wikipedia.org/wiki/Pot-in-pot_refrigerator


Edit: You do not want the inside box/pot to have any insulating property's at all, A clay pot or wall will transfer heat quickly.

Wood, Methinks would not be a good choice , because heat transfers very slowly through it. And is a much better insulator than clay.

The ideal is to remove heat from the inside too the outside quickly.

IMO

[Dogman]

Slightly off topic , but same theme.

On my last post in this thread, I brought up canvas water bags, haven't thought or used one of them in years. In areas that are hot and have low humidity (dry) you can cool water by using canvas bags or buckets.
The canvas soaks and the water outside evaporates , cooling the water stored inside well below air temperature. Just hang them in a shady spot so air can circulate around them and you have a instant water cooler!

Just a thought!

http://1.bp.blogspot.com/_M9JRlA_879c/SC8hBxbsKOI/AAAAAAAAAmU/1g7tAbaTods/s400/desert+water+bag.jpg

http://www.thepirateslair.com/images/soviet-union-russian-dinnerware/lifeboat_canvas_bag.jpg

http://jacidawn.files.wordpress.com/2011/08/048.jpg


Edit: The more air flow the more evaporation = more and lower temp cooling! ;D

[solid]

Thanks a lot, Dogman. That was extremely helpful.

I'm thinking teak might work, it will absorb moisture like any wood does. However, the thickness of the teakwood box would matter. Perhaps a thin box, such as 1/2 or even 3/8 inch teak. Teak is very strong. Furthermore, the inner box, I could possibly build out of polypro, or some fiberglass material that's waterproof and non-insulating. The local hardware store has those thin sheets of polypro you can buy for bathrooms, etc.

Regarding my weight question, the weight would be mostly the sand. 1 inch of sand surrounding the inside wouldn't weigh that much...

I should try and build one. If it works, I'd have a place store cool drinks outside while I'm sailing. If it doesn't work, I'd end up with an expensive storage box, but could still make use out of it.

[Heimdhal]

The only downside is that these methods do not work in places with ambient humidity over 50%, which sucks for us here in the south cause I would love to be able to use something like this if the grid ever went down, but I doubt it work very well at all.


Solid, you might want to try this on the small scale before you go building the whole thing on the boat for that very reason.

[Dogman]

The only downside is that these methods do not work in places with ambient humidity over 50%, which sucks for us here in the south cause I would love to be able to use something like this if the grid ever went down, but I doubt it work very well at all.


Solid, you might want to try this on the small scale before you go building the whole thing on the boat for that very reason. Yea!
Kinda hard to build and requires something that requires low humidity to work, while you are floating on top of an ocean.


1585


Edit: If floating on deep water, throw what you want cooled over board, past the thermocline it is definitely cooler. Used to, when fishing and no ice was available, toss my beer overboard and pull up as needed, not cold , cold, but cool enough!

[solid]

Yea!
Kinda hard to build and requires something that requires low humidity to work, while you are floating on top of an ocean.

I think you guys are right. In all my studies, all the books, and talking to folks, other sailors...I've never heard of any seaman doing anything like this before. There has to be a reason for that. The high humidity pretty much destroys this idea for me, and here I had conjured up this potentially great design.

Dogman, I'll just have to get my solar up and running to provide for cold drinks, though I do very much look forward to doing the tropic island dishwashing method. :) Swinging at anchor, what you do, is just drop all your dirty dishes overboard in the evening. Then, the next morning, dive down and get them. All the little ocean critters should have picked them clean by then. Yayya.