I found this web page from Futurism that could really be of important use to anyone. Technology has come a long way but, every electronics that we invent would need electricity, and thus defeating the purpose of having a renewable source.

Click here: https://futurism.com/images/cheap-tech-fixes-that-could-transform-life-in-developing-countries/

I believe this could really transform the way we live and benefit mankind. This is not embarrassing but, empowering human lives to shift to a better way of living.

Personally, from these examples, I prefer the Zeer Pot because I’ve tried it and it really works! I just bought clay pots from a gardening store (costs $6), one large and a smaller one. Placed the smaller one inside, filled the surrounding pot with sand (from construction sites), and got a wet rag to cover the pot. I tested it by putting a banana and an apple because bananas rot immediately within a few days with blackening skin. After three days, I compared the banana in the open and it easily blackened, while the banana in the Zeer pot is surprisingly still yellow. Although, I must say that molds started to form at the stem of the banana. I might recommend for you to put it inside a plastic bag? I must also say that you must wet the rag and put one glass of water on the sand everyday to keep it cool.

In conclusion, the Zeer pot is an essential device that could really help nations including poor countries and those in hot climates. But, I must point out that even I do use it now even we have refrigeration. Why? Like the experiment shows that when you put a banana inside a refrigerator, its skin blackens immediately because of moisture since it uses a vapor compressor. The Zeer pot is something we must use in small scale or large scale definitely.

See https://en.wikipedia.org/wiki/Refrigerator#General_technical_explanation.

Zeer pot

Source from: https://futurism.com/images/cheap-tech-fixes-that-could-transform-life-in-developing-countries/