Yakhchal

Yakhchls are ingeniously engineered structures that use evaporative and radiative cooling, optimised by the dry, desert climate’s low humidity to efficiently store ice. Their designs typically include a reservoir, shade walls, and ice pits, though some variations use only select components.

The yakhchl is an ancient Persian ice house, designed to make and store ice in desert climates like those of the Dasht-e Lut and Dasht-e-Kavir. Today, the term "yakhchl" is also used in Iran, Afghanistan, and Tajikistan to refer to modern refrigerators. They date back to at least 400 BCE, were built by Persian engineers to store ice year-round for uses like food preservation and making traditional desserts. While many have deteriorated due to modern refrigeration, some well-preserved examples remain and are now inspiring sustainable, low-energy architectural designs.

Yakhchls use passive cooling methods like the solar chimney effect and underground chambers to maintain temperatures well below the desert heat, aided by thick, insulating walls made of sarooj—a water-resistant mortar. Many are connected to qanats and equipped with windcatchers (bâdgirs) to enhance airflow and cooling, while their design also includes features for ice storage and drainage, such as layered insulation and base-level holes. Shade walls, often up to 15 meters high and built in an east–west direction, are essential in creating temperature differences of up to 20 °C to aid ice production, storage, and harvesting. Water is typically channeled along the shaded north side for pre-cooling before entering the yakhchl, where it is stored or frozen in pools, enhancing the efficiency of evaporative and radiative cooling.

Many yakhchls featured shallow ice pools designed for on-site ice production or to supply water for cooling, often shaped like large, shallow channels without special surfacing. At night, these pools benefited from minimal heat gain and efficient radiative cooling, allowing water to freeze naturally in the dry desert air, aided by shade walls and evaporative processes.

[edit] Related articles on Designing Buildings

• Absorption refrigeration.
• Cooling tower.
• Earth-to-air heat exchangers.
• Evaporative cooling.
• Ground energy options.
• Ground pre-conditioning of supply air.
• Ground source heat pumps.
• Night-time purging.
• Pantry, buttery, larder and scullery.
• Phase change materials.
• Refrigerants.
• Thermal labyrinths.
• Thermal mass.
• Thermal storage for cooling.

[edit] External links

http://www.historyofrefrigeration.com/refrigeration-history/yakhchal-ancient-refrigerator/#google_vignette