It’s really hot out there and in some countries, it’s deathly hot and not everyone has access to air conditioning. One of the places dealing with this particular issue right now is Bangladesh, India. In order to help keep people cooler, two companies teamed up to create the Eco-Cooler, an air conditioner that doesn’t use any electricity.
This innovation was brought about by the partnership of Grey Dhaka and Grameen Intel Social Business Ltd. Together they came up with creative solution to the problem of overheated homes by using waste products, particularly, empty plastic bottles.
The simple to make boards uses the bottles to compress and cool the air as it passes through. When the Eco-Coolers are installed in the windows of the tin huts of Bangladesh, they can lower the by 5 degrees Celsius which may not seem like a lot but is better than nothing at all. If you’re interested, you can make your own Eco-Cooler! The instructions are on the linked website for you to follow and it can be made with common materials.
https://www.youtube.com/watch?v=oSbZWNk84F4
The explanation of how it works is wrong. Compression raises the temperature, not lowers it; and the release of pressure at the mouth of the bottle lowers it again, so the effect of the funnels is a wash. If you add holes to a tin wall, of course it’s going to get cooler. If you replace tin sheet, which conducts heat quickly, with something that conducts heat slowly such as cardboard, plywood, or styrofoam, it will get cooler, too. Just add more ventilation and shade the sunward side of the building with a tarp wall, and you’ll get a lot more cooling without all that work.