We are just now realizing that for years Africa has been on the forefront on green technology. Farmers produce crops and because of the extreme heat and high humidity the crops deteriorate rapidly. An answer to this would be refrigeration, but buying energy would be expensive. One community in Africa relies on green beans for their income and to fix this issue, they came up with this low energy solution.
The beans are picked warm and the temperature must be brought down to keep them viable. They don't have fridges but they do have charcoal coolers. A building that keeps the temperature at a level that is able to maintain the beans for extended periods of time.
With wood planks, coal, mesh fabric, and a pipe they were able to construct these buildings.
They created the structure of the building first and then packed the walls with charcoal using fabric to keep it in place.
Next they drilled holes into a pipe and installed it at the top of the front wall.
They then ran water to it so that it is constantly dripping water into the charcoal.