Around 400 BC, the Persians invented a cooler that allowed them to store ice all year round. The cooler goes by the name of "yakhchāl". Yakhchal is a type of evaporative cooler which cooled the air through the evaporation of water. Above ground, the structure had a domed shape, but had a subterranean storage space. It was often used to store ice, but sometimes was used to store food as well.
These thousand year old structures were made from composed of sand, clay, egg whites, goat hair, lemon juice, ash and a water resistant mortar called sarooj. It used a heat resistant type of clay which could keep the interior nice and cool. The structures would allow for cool air to come in from the entries at the base and the warm air would exit from the top of it.
These thousand year old structures were made from composed of sand, clay, egg whites, goat hair, lemon juice, ash and a water resistant mortar called sarooj. It used a heat resistant type of clay which could keep the interior nice and cool. The structures would allow for cool air to come in from the entries at the base and the warm air would exit from the top of it.
