In 2022, MIT researchers built a 4-inch cooler that kept food fresh without electricity

On a hot roof in Cambridge, Massachusetts, a small experimental device sat in the sun without a fan, compressor or electrical connection. Its job was simply to get colder than the air around it. Water moved through one part of the device, heat escaped through another, and layers of insulating material helped keep the cooling from being undone by sunlight.That rather quiet experiment points to a problem that is becoming harder to ignore. Cooling is increasingly important as temperatures rise, yet conventional air conditioning depends on electricity and reliable infrastructure. In places where either is scarce, keeping food, water or indoor spaces cool can be difficult. An MIT team has been testing a different approach, combining several passive cooling methods in a single compact structure.MIT researchers combined three cooling effects without electricityThe idea is not to replace air conditioning with a single miracle material. Instead, the system brings together three familiar physical effects that have usually been used separately: evaporation, heat loss by infrared radiation and thermal insulation.Individually, each has limitations. Evaporative cooling becomes less effective whe...