Persians were also recognised as innovators in the fields of refrigeration, cooling, and ventilation.
The first crafting methods for prehistoric refrigerators date back to around 400 BC, making Persian expertise in cooling and refrigeration technology even older. These structures, known as Yakhchals, typically included sizable, well-insulated underground storage areas, sometimes exceeding volumes of 1,800,000 cubic feet. Additionally, the subterranean spaces had Qanat, or wind catchers, for generating natural ventilation that helped with temperature drops to even freezing points. With the aid of a mortar made of sand, lime, egg white, goat hair, and ash, these underground chambers were literally topped off by stepped dome-like structures made of heat-resistant mud bricks that frequently reached heights of over 60 feet.