natural refrigerator
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How to Make a Natural Refrigerator

It is no secret that up to 1.3 Billion people are living without electricity as we speak. This means that something as necessary as a refrigerator is but a dream to that population. Does this mean that they are completely incapable of preserving food? Not at all. You may find that some will use methods as ancient as drying and salting for meat.

Now, the modern world expects us to be more creative than that. And in that context, today we will be looking at two homemade refrigerator examples that do not need electricity. One will be made out of very cheap items. Items that you probably already have at home. While the other will put your handy work to the test.

natural refrigerator pin

Both of them have applied the concept of evaporative cooling. However, they are not the same in terms of efficiency. One records temperatures as low as 4.5 degrees Celsius while the other can take it down to 17.3 degrees. If you already have a refrigerator, these two can serve you well in times of blackouts. They are also very easy to build, especially the first one. You can build it all without having to buy anything extra.

Natural Refrigerator With Easy To Find Materials

If you grasped the concept of evaporation while you were in school, this shouldn’t be complex. It works based on a very simple principle – evaporation causes a cooling effect. Which if you think about is very obvious. Try and remember the last time you came into contact with the clinical spirit. Thanks to its lower boiling point, it evaporates much faster than water ever would. Leaving behind that cooling effect we’re talking about. As an experiment, pour some on your skin and observe. You should feel a very cool sensation as the liquid evaporates. If not, you must be an alien. 

Now, for this natural refrigerator, we will start with a paint bucket.

This bucket will act as our outermost layer. There is no preference for color or size, just any you can find. However, make sure you have a clay pot that can fit inside it. Next, we add sand into the bucket till its quarter-full.

natural refrigerator instructions sand
Screenshots taken from CrazyIandianHacker video https://youtu.be/280AlNuyasQ

The science of this will be made clear at the end. We will then need to put the clay pot we picked out inside the bucket.

natural refrigerator pot

After that, pour more sand into the bucket till the clay pot is completely immersed. Just make sure you don’t get any sand inside the pot. We don’t want the things we put inside it to be covered with sand.

natural refrigerator more sand

Once that is done we will need two towels. One of them will be placed carefully around the pot, on top of the sand that’s showing. Be careful not to cover the top of the clay pot.

natural fridge

The next step would be to cover the pot with a metallic cover. At this juncture, we are almost done with our natural refrigerator.

Next, pour water on the towel. This will lead to the water slowly draining into the sand below it. And this is exactly what we want to happen. You can choose to pour water directly into the sand without the towel. But what we are trying to achieve here is gradual cooling, which would last longer if the water evaporated slowly.

natural fridge towels

This is where we put whatever we want to stay fresh into the clay pot.

fridge

Vegetables are mostly what last the longest in the conditions provided here. Extremely perishable goods will only be able to last a maximum of 24 hours. Lastly, cover the whole bucket with a wet towel.

natural fridge covered towel

When the experiment was done, it was 44 degrees Celsius outside. After an hour, the temperature inside the clay pot was 26.9 degrees Celsius. After three hours, the temperature had dropped down to 17.3 degrees. According to this data, a gradual reduction in temperature was achieved. Exactly what we wanted. Once the water in the space is all gone, we will have to add some more for the process to repeat.

How Does it Work?

Evaporative cooling. If you have never heard of the word, it is what happens when the clinical spirit evaporates on our hands and we feel cold in that spot. This refers to the experiment we talked about earlier. We all know that everything is made up of tiny molecules – even water. So when water molecules are vibrating during the evaporation process. Some molecules break off and hence the water’s kinetic energy reduces.

This reduction in kinetic energy is what we call cooling in simpler terms. The effect will be felt on the clay pot since the water molecules are in the sand. This in turn will make the inside of the pot cold as well, which eventually results in the contents getting cooled. Simple enough? Get to work!

Natural Refrigerator With Optimum Performance

This design was originally invented by a group of students from University of Calgary. They named it the WindChill Food Preservation Unit.

The making of this natural refrigerator starts with a funnel. Its work is to concentrate ambient air into a pipe that has been buried underground. I’m sure from the first design you can imagine what is the reason for this. This pipe then emerges out of the ground to go into a glass evaporation chamber.

advanced natural refrigerator
pic from https://challenge.biomimicry.org/en/custom/gallery/view/2576

The chamber is made up of four walls of glass held together at the corners by blocks of wood covered with glue. Very creative right? Inside the chamber is a coiled copper wire that is immersed in water. This is where the evaporation takes place. To increase efficiency, a solar-powered fan was installed to help the process along. This slightly goes against the natural law but we don’t need it for the natural refrigerator to work.

We only need it when trying to optimize performance. So if you don’t have it you won’t have to add it for you to continue along. The evaporating water around the pipes causes the air inside to get cooler and cooler. Immediately after that, the air is forced underground through another pipe. The pipe emerges again to go into a refrigeration chamber.

This is where all the magic happens. The refrigeration chamber is where we will be placing the items we want to get cooled. This process is not as simple as the first one so follow the steps carefully.

Without optimization, the Windchill Food Preservation Unit goes down to a temperature of 14 degrees Celsius. Even without optimization it still performs better than the sand technique. After optimization, the temperatures go all the way to 4.5 degrees Celsius. A feat I’m sure you hadn’t thought was possible for a natural refrigerator.

How Does it Work?

Jorge Zapote explains how the WindChill works.

The fundamental concepts are still the same as the first refrigerator we made. However, in the first one, the cooling effect came from water directly onto the clay pot. Here the cooling effect is directed towards air and is repeated twice. No wonder it can register cooler temperatures. If you are not able to make this natural refrigerator, take solace in knowing that I too failed terribly. But if you haven’t tried to build it, don’t let me stop you. My handy work is not really the best.

Remember you will want to build it outside since the pipes need to go underground and the coil needs access to sunlight to work.

Requirements to Build the Refrigerator

1. Cooper Wire

You can find this part for as low as $10 on Amazon.

2. Funnel

For this part, it’s hard for you to go wrong. Almost any funnel will do, and almost all of them are very affordable. But just in case you want to be sure, here is our recommendation:

3. Piping

This natural refrigerator does not need a long pipe. 3 meters would even be too long. Most people can cut this off an existing pipe they have at home

This natural refrigerator does not need a long pipe. Most people can cut this off an existing pipe they have at home but if you need piping, here it is:

4. Glass Cutter

This will be used when building the evaporation chamber. The amount of glass needed will be respective to how big you want your chamber to be. Choose wisely knowing that the size is directly proportional to efficiency. Here is our recommendation of which one to buy:

5. Solar Fan

If really going for gold with this, you’ll want a solar powered fan to get the best performance possible and we found this wee solar powered gem on AMAZON.

In Conclusion

We all need to come up with better ways to survive since electricity is not getting any cheaper. From these designs, you can come up with a better one of your own if you have the time. The science is simple and maybe you will discover something I missed. Going natural is also good for the environment at large.

Your invention may end up being what replaces refrigerators in the greener world some of us dream of. Honestly, it’ll be hard for anyone to get rid of their refrigerators anytime soon. But out there is a world of possibilities, anything is possible if you put the work in.

Sources

1. https://www.sciencealert.com/this-clever-new-refrigerator-keeps-food-cold-without-electricity

2. https://youtu.be/280AlNuyasQ