A charcoal cooler is a storage chamber that uses evaporative cooling to keep food fresh without electricity. It's made of an open frame with charcoal-filled sides that are kept moist. * How it works Warm, dry air passes through the moist charcoal The charcoal draws energy from its surroundings Water evaporates into the air, cooling it * Where it's used They can be used to store fruits, vegetables, and dairy milk * How to build one Charcoal coolers can be built from locally available materials Yo

Swamp Cooler Improvement