Yakhchal

Iranian Ice house also known as Yakhchal, were the early ancient refrigerators.
A Persian ice house, or yakhchal, is an ancient passive refrigerator allowing the storage of ice in the deserts of Iran. Ice was collected in winter and stored in the ice house where it was kept cool in summer by the domed shape and thick walls made from a special mud called srooj, composed of sand, clay, egg whites, lime, goat hair, and ash, which was resistant to heat transfer. Ice-houses are believed to have been used in Iran as early as two thousand years ago