Around 400 BC, long before the invention of electricity, engineers from ancient Persia developed a sustainable technology that kept their ice from melting, even throughout the boiling summer.
Engineers, during that time, built dome-shaped evaporation coolers above the ground with copious amount of underground space for ice, food and other putrescible products. These ancient evaporation coolers are called ‘Yakhchal’.
This effective method of storing ice in a ‘Yakhchal’ may seem a little complicated, but, this technique was a simple process that even the poorest could afford.
Exterior Of A Yakhchal In Iran
The structure of the ‘Yakhchals’, above the ground, was a humongous mud brick dome, that could rise above the height of around 60 feet. Below the ground surface, there was an empty space that measured up to 5000 cubic metres and it was surrounded with very thick walls that measured at least 2 metres at the base. These walls were made out of a type of mortar called ‘Sarooj’. This mortar was a mixture composed of clay, sand, egg whites, goat hair and ash in a very specific proportion. ‘Sarooj’ was also resistant to heat transfer and it was believed to be completely waterproof.
Many of the structures also contained a system of windcatchers that helped in bringing the temperatures inside the ‘Yakhchals’ to frosty levels during the summer.
Interior Of A Yakhchal In Meybood, Iran
Ice was accumulated in this ‘Yakhchals’ during winters from nearby mountains. Some ‘Yakhchals’ also had underground channels called ‘qanats’ to carry water from nearby rivers, lakes or ponds.
Because of its effective applications and major architectural elements, these structures are considered as marvels of ancient architecture. Some of the ‘Yakhchals’ that were built more than hundreds of years ago still remain intact. In the present day Iran, Afghanistan and Tajikistan, the term ‘Yakhchal’ is used to refer to the modern day refrigerators.