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A yakhchāl ( 'ice pit'; yakh meaning 'ice' and chāl meaning 'pit') is an ancient type of ice house, which also made ice. They are primarily found in the Dasht-e Lut and Dasht-e-Kavir deserts, whose climates range from cold (BWk) to hot (BWh) desert regions.
In modern-day Iran, Afghanistan, Tajikistan and Israel the term yakhchāl is also used to refer to modern Refrigerator.
The structure typically had a domed shape on the ground, a subterranean storage space, shade walls, and icy pools. It was often used to store ice, but sometimes was used to store food as well as produce ice. The subterranean space and thick heat-resistant construction material insulated the storage space year-round. These structures were built and used since ancient times in Iran.
The also recorded to adopt the technology of Yakchal. Humayun (r. 1530–1540, 1555–1556) expanded ice imports from Kashmir to Delhi and Agra, insulating blocks with straw and saltpetre to slow melting, a Persian technique. Early Baraf Khana (underground pits) stored ice, adapted from 'yakhchāl' for preservation. primary source: Akbar (r. 1556–1605) organized ice transport from Kashmir to Delhi, Agra, and Lahore via a 14-stage relay system, delivering ice in two days using saltpetre. The ab-dar khana at Fatehpur Sikri used sandstone cisterns and qanats, resembling yakhchāl, to cool water and make sherbets and early desserts.
During the era of Jahangir (r. 1605–1627), Tuzuk-i-Jahangiri describes baraf khana as insulated cellars storing ice for palace cooling, food preservation, and kulfi, a frozen milk dessert with pistachios and saffron. Ice was harvested in Lahore from shallow ice pans and stored in straw-lined pits.Shah Jahan (r. 1628–1658).
Although many have deteriorated over the years due to widespread commercial refrigeration technology, some interest in them has been revived as a source of inspiration in Low-energy house and sustainable architecture. And some, like a yakhchāl in Kerman (over a mile above sea level), have been well-preserved. These still have their cone-shaped, eighteen meter high building, massive insulation, and continuous cooling waters that spiral down its side and keep the ice frozen throughout the summer.
However, they varied a lot because, as some used all three components, whereas others were simply a large shade wall over a thin pool.
The yakhchāl is built of a unique water-resistant mortar called sarooj. This mortar is composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions, is resistant to heat transfer and is thought to be completely water-impenetrable. This material acts as effective insulation all year round. The sarooj walls are at least two meters thick at the base.
They also often have access to a qanat (Iranian aqueduct), and are sometimes equipped with bâdgirs (windcatchers or wind towers) built of mud or mud brick in square or round shapes with vents at the top which funnel cool air down through internal, vertically placed wooden slats to the water or structure below. A bâdgir can also function as a chimney, releasing warm air out the top and pulling cool air in from a base opening or a connected qanat (air in a qanat is cooled by the underground stream). It is this construction that allows the ice house of a yakhchāl to take advantage of evaporative cooling, keeping the structure cool to well below ambient temperatures.
The ice inside the structure was often separated using wood, straw and mud to separate the layers of ice and keep them from sticking to each other. Furthermore, most designs incorporated a hole at the bottom that would connect back to the qanat, or simply act as a well for drainage.
Water is often channeled from a qanat to a yakhchāl, which is used to fill the provisioning pools or used to power the evaporative cooling throughout the ice house. Incoming water is channeled along the north side of the wall so that radiative cooling in the wall's shadow pre-chills the water before it enters the yakhchāl (as pictured at the yakhchāl at Kowsar). Ice is then brought from either the ice pools covered by the walls, or from nearby mountains to be stored in the reservoir.
By night time, the ice pools would often have a negative energy budget:
This meant that ice pools could use the cold of the desert nights and/or radiative cooling to freeze water which would later be transported to storage as ice.
See also
Further reading
(1980). 9780670396832, Viking Press. ISBN 9780670396832
External links
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