These structures, scattered across Iran, functioned as primitive refrigerators
In the waterless expanses of the Persian desert, an amazing and ingenious ancient technology was discovered, known as yakhchāl, which means “ice pit” in Persian. Yakhchāl (Persian: کلکر; yakh meaning “ice” and chāl meaning “pit”) is an ancient type of evaporative cooler. By 400 BC, Persian engineers had mastered the technique of using yakhchāl to create ice in the winter and store it in the summer in the desert
It reveals our ancestors’ sophisticated approach to ice production and dates back to 400 BC. These structures, scattered across Iran, functioned as primitive refrigerators, using a cooling system designed to store ice year-round. The yachts had a distinctive domed shape that housed a huge underground storage area. Constructed of thick, heat-resistant materials, the yachts used an overhead evaporative cooling system.
Working in harmony with the natural climate, cold air enters through the inlets at the base, while the conical design helps expel the remaining heat through the openings at the top. The process of ice production began with shallow lakes filled nightly by freshwater channels. Protected from the sun’s rays by shading walls, the lakes froze during winter nights.
The collected ice was then transferred to a yahchal made of local materials such as adobe, clay, egg white, goat fur, lemon juice and waterproof mortar. These remarkable structures played a vital role in preserving food, drink and possibly cooling the buildings during the hot summer months. Today, 129 yakhchals remain as a historical reminder of ancient Persian ingenuity.