Cheap Solar Fridge

This instructable is being entered in the Green Tech Contest so please vote.

This solar fridge is a simple and quick diy project. The reason I decided to build it was because the fridge in your house takes up a ton of energy.  This fridge is so cheap and reliable that it can be used in 3rd world countries.  It takes about 15 to 30 minutes to complete and it only cost around $15 dollars.  

Here is what you need

1 large clay flower pot
1 small clay flower pot
 sand  (I used about 1/4 of a bag) 
 towel 
 water
 clay or plumbers putty   (only needed if there is a whole in the bottom of the pot)   

Step 1: Filling Up the Holes

The first step is to see if you have a hole at the bottom of your pot.  If there is not a hole then you can skip this step.  If there is a hole then take your clay or putty and firmly press it into the hole and cover it.  Make sure there is no gaps for water to leak out.

Step 2: Even the Pots

Fill the larger pot with a layer of sand.  Then put the smaller pot inside the larger one and level the sand until both pots are at even height.

Step 3: Finishing With the Sand

Fill the remaining area between the pots with sand.

Step 4: Time to Put the Water In

Pour water into sand to saturate it completely.  Once the water begins welling up instead of soaking in, you can stop.

Step 5: Stock the Fridge

put any items you want into the fridge.

Step 6: Almost Done

Now you have to soak the towel and place it over the top of the pots. 

Step 7: Usage of Your Fridge

Make  sure you put your fridge in a shaded place.  Also return once or twice a day and refill the sand with water and dampen the towel.

Step 8: How It Works

The action that allows it to stay cool is the evaporation of the water surrounding the smaller pot.  As the water evaporates, heat draws out from the smaller pot, keeping the contents inside much cooler the the surrounding environment.

Comments

[wtim24]

do you know how cooling this technique allows you to go. if not an exact number an approximate will do thanks.

[ragtimelil]

I tried this and did not have success. I think it works in a dry climate but not in a humid one.

[cdrobsonjr]

Evaporative coolers - which this truly is - rely on, oddly enough, evaporation. When your ambient humidity is high, the differential between the wet pot and the surrounding air is small, so less evaporation takes place and hence less cooling takes place inside. Your intuition is correct.

[Satrah101]

Hello all can i ask how cool does this get.

[iffee]

How it is solar???

[jeffeb3]

It's not solar. "Make sure you put your fridge in a shaded place". A better title would be "Evaporative Fridge" or "No-Electricity Fridge" or "Cheap Portable Fridge".

[rimar2000]

Yes, it is indirectly solar, bacouse the wind is due to sun.

[phepner]

then it's indirectly nuclear also ... nice instructable anyway

[PaulT241]

Alright! We went from low-tech to high-tech - It's a nuclear fridge. :-)

[SpikeFiend]

Fossil fuels are also indirectly solar energy. ;)

Would a lid on top of the center pot help keep it cooler? Assuming the evaporation takes place in the outer pot.

[rimar2000]

Both you are right.

[fzbw9br]

the wind is not only caused by the sun, but by pressure differences on the earth, so it could be called, an "Indirect, SolaNuclear Low Pressure EvapCooler"

AKA: InSoNuLPEC device

[rimar2000]

Yes, you are right.

[martinbolton]

Thats what I was thinking.
Confused with 'evaporative'

[iffee]

It is evaporative not solar. Think it is night time and cooling will continue in absense of sun!!!

[bcavaciuti]

you could fill the bottom holes with clay mixed with fibres(grass/rope/anything fibrous to hold its strength) this is for 3rd world countries or any people that dont have putty :)

[PaulT241]

Clay could be used in place of putty. Some third-world countries may not have putty, but some areas of the world have easy access to clay.

[BrianB382]

It's no joke. There are a number of names for this type of cooling system, but one is called an evaporative cooler. Check out https://en.wikipedia.org/wiki/Pot-in-pot_refrigerator for more info.

[mobius1ac]

BTW, this is called a Zeer Pot, it is different from a Refrigerator. A fridge has to have an active element to it.

Great product, but title is misleading to those of us looking for an actual fridge

[aurasolar]

You should named it "Power Free Fridge" rather than "Solar Fridge". But your work is awesome. Thumbs up.