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Yakhchāl (Persian: یخچال ice pit; yakh meaning ice and chāl meaning pit) is an ancient type of refrigerator. The word also means glacier in Persian. In 400 BC, Persian engineers had already mastered the technique of storing ice in the middle of summer in the desert.[1] Above ground, the structure had a domed shape, but had a subterranean storage space; it was often used to store ice, but sometimes was used to store food as well. The subterranean space coupled with the thick heat-resistant construction material insulated the storage space year round. These structures were mainly built and used in Persia (Iran). Many remain standing that were built hundreds of years ago.
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