Jalali Castle's Natural Refrigerators

Iran, Iran

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Jalali Castle’s Natural Refrigerators are two ancient subterranean “yakhchāl” (icehouse) structures located just outside the Seljuk-era fortress walls of Ghal’eh Jalali on Alavi Street in Kashan, Isfahan Province, Iran. Above ground, each refrigerator appears as a modest domed building, but beneath the dome is a deep pit that extends underground; this pit, combined with thick clay and earthen walls, creates a naturally insulated space that stays cool even in Kashan’s hot, dry summers. The design uses simple physics: the high internal ceiling and deep pit allow hot air to rise and escape, the clay walls absorb moisture and remain cool, and the thick insulation blocks sunlight, so the interior can be used to store ice, dairy, fruits, and other perishable goods for long periods without any modern refrigeration. In the past, these icehouses were connected to a qanat (underground aqueduct) system that supplied water to freeze into ice, especially in winter, and then keep it stored in the cool underground chambers, making them effective “natural refrigerators” for both the castle’s occupants and local farmers. Today, the two domed structures are recognized as a unique historical and engineering feature of Kashan; they are open to visitors and illustrate how ancient Persian societies adapted to arid climates by turning simple materials like clay, earth, and shelter into efficient cooling systems.