Yakhchals: Ingenious Ancient ‘Refrigerators’ Could Store Ice In The Hot Desert

A. Sutherland - AncientPages.com - These ancient structures, called yakhchals should not be confused with pyramids or ziggurats.

The yakhchals (‘yakh’ means ‘ice’ and ‘chal’ means ‘pit’) are in fact ancient “refrigerators” used to store ice and other food items.

Yakhchal in Yazd Province

Modern refrigerators and freezers that we possess today, are by no means new inventions. Ancient people had their technological ideas and they were similar to ours.

The yakhchals  were mostly used in Persia about 400 BC. Ancient Persian engineers mastered the technique of storing ice in the middle of summer in the desert. People harvested ice and snow even much earlier, in 1000 BC. There is also written evidence that ancient Chinese, Jews, Greeks, and Romans had a similar tradition.

But what people that lived in deserts did? Some of them, like Persians, built yakhchals, a type of evaporative cooler, which cooled the air through the evaporation of water. The yakhchals were made of a special mortar called sārooj, composed of sand, clay, egg whites, lime, goat hair, and ash which acts as an insulator. Above ground, a yakhchal is in a shape of a dome, and it has an underground storage space, which is used to keep ice or less often - food.

Ancient people got the ice from the icy river in the winter and stored it. Many of the yakhchals  - although they were built hundreds of years ago - they survived to the present day.

The twin ice-pits on Sirjan, Kerman Province, are surrounded by high walls and were constructed with mud-brick.

The twin ice-pits on Sirjan, Kerman Province, are surrounded by high walls and were constructed 108 years ago with mud-brick, the ice-pits are surrounded by high walls.

Another way to keep the temperature low was to use the wall made on the north side of the yakhchal. The water channeled along the wall would freeze faster on a winter day thus producing more ice.

The ice produced and stored was kept in large underground pits. In most yakhchals, the ice was created by itself during the cold months of the year. The water is channeled from the qanat (Iranian aqueduct) to the yakhchal and it freezes upon resting inside the structure.

The yakhchals were constructed with up to two meters thick walls made of a special mortar composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions.

These remarkable structures were not only resistant to heat transfer but also completely water impenetrable.

The yakhchals have not been forgotten and erased from history. Even today, Iranians still call the modern fridges and freezers “yakhchals”. One of the yakhchals that still stands today is in Kerman, the capital city of Kerman Province, Iran. It is about eighteen meters high, and one of the rare surviving yakhchals.

Sometimes, the ingenious ‘refrigerators’ were equipped with a system of windcatchers or wind towers that could easily regulate temperatures inside the yakhchals, especially during very hot summer days.

Written by – A. Sutherland AncientPages.com Staff Writer

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