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Ancient Air Conditioning





ĀB ANBĀR | رابنا بآ
The ab anbar is a traditional water storage reservoir of ancient Iran usually submerged and covered with a double walled dome (yakchal). Persian engineers in 400 bc developed a way to freeze and store ice through the desert summer. Water from subterranean channels (quanat) was channeled to the shaded north face of a wall where it would freeze more quickly in winter. The ice was then stored in a nearby double walled dome (yakchal). Water channels (karez/quanats) and wind escapes (bagdir) were used in combination to substantially cool the submerged room. The wind passing the opening of the bagdir creates a low pressure due to the Bernoulli effect. Replacement air is drawn from distant inlets and is passed over the water in the cooler subterranean qanat. Contact with the cool walls of the qanat and the evaporation of water into the dry air cools the air as much as 27 degrees Fahrenheit.



Computational Fluid Dynamics opens new possibilities for the design of forms for passive heating and cooling. Credit: Bushra Obeidat, Hammam Kamal, Amal Almalkawi
Computational Fluid Dynamics opens new possibilities for the design of forms for passive heating and cooling. Credit: Bushra Obeidat, Hammam Kamal, Amal Almalkawi




Halawa House - Hassan Fathy Malqaf with Baffles - Hassan Fathy - Natural Energy and Vernacular Architecture MALQAF یگداب The malqaf is a small hollow tower with a directed opening which catches breezes and directs fresh cooling air into a building below. When the opening is on the leeward side a negative pressure is created within the building due to the Bernoulli effect. This negative pressure draws air from an inlet located elsewhere. Often the air is drawn underground or over water to cool it and remove dust before it enters the space. BÂDGIR فقلم Often multiple wind-catchers / wind-escapes would be combined in a single tower to catch winds of varying direction. Inscriptions found in Egypt indicate that counterposed wind-catchers were used in pharaonic times but the technology was most developed in ancient Iran where the towers are called bâgdir. The multiple directions have an additional advantage in that the windward and leeward sides of the tower, separated by a septum, develop opposed pressures which can induce more substantial airflow than a single directed opening. Often multiple bâgdir would be placed around a water reservoir, āb ānbar. By drawing air over the water a substantial evaporative cooling effect was obtained. This ancient refridgeration was capable of maintaining near freezing temperatures without electricity. Bâgdir of Dolat Abad in Yazd Iran QUANAT ةانق The qanat is a gravity fed horizontal well system that is able to provide a reliable supply of water for irrigation and human settlements in hot arid and semi-arid locations. The qanat draws water from upland aquifers often in the steppes of mountains which receive consistent rainfall and delivers it to land where the water table is too deep to reach by vertical well. The channel eventually surfaces as its slope is slighter that the ground above. A series of relieving wells aid in the construction, maintenance and continual flow of the qanat. The qanat is a naturally sustainable means of extracting water since it draws exactly what the aquifer can supply. Many towns throughout the Middle East, North Africa , and parts of Asia still rely on these ancient channels for water. The layout of these towns is largely determined by the qanat and the sloped distribution of water. Quanats at Gur - Subterranean water channels were integrated with wind escapes to cool homes in ancient Iran.Image Credit - Georg Gerster





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