Ancient Cooling Systems

Yakchals, ancient refrigerators found in Persia, date back to at least 400 BC and showcase remarkable cooling techniques in extremely hot climates. These structures, made of a unique mixture including sand, clay, egg whites, and goat hair, provided high insulative properties, equivalent to modern materials. The construction utilized thick walls to create an effective thermal barrier, which allowed ice to be produced and preserved even during summer months. The combination of sheltered channels for water diversion and a conical dome shape enabled optimal cooling through convection currents.