Yakhchal

A Yakh -chal (Persian يخچال ) is a traditional refrigerator that was distributed mainly in Persia in the 5th century.

In these underground dome-like buildings ( up to 5000 m³ volume) was kept ice, they were also used for the preservation of food. The 2 meter thick walls of the dome prevented the penetration of heat into the interior. The ice was brought and stored in order to then use it during the summer months for the traditional Persian ice cream in the winter months from the nearby mountains.

Today existing Yakh -chal usually stand for over 100 years.

Operation

First, very large basins were dug with about 40 to 50 cm depth in the soil. After that, the water from a qanat or a stream was passed into the pelvis. During the night, the ice that was transported out of the basin and stored in the memory of the refrigerator compartment formed.

A very high brick or mud wall was built on the south side of the basin to the day to prevent direct sunlight on the pool. So the bottom of the water basin was much cooler than the adjacent terrain to accelerate the Eisbildungsprozess. Also two other walls were built on the western and eastern sides often so that the pelvis was screened at the sunrise and sunset from the direct rays.

For the construction of a special mortar ( Sarooj ), a mixture of sand, clay, lime, ash, and goats' hair, etc., was used, the heat- resistant worked in a given mixing ratio.

The Yakh -chal, which were built in peripheral areas of deserts above ground had, a huge dome-like part and underground a large and very deep (up to 15 m ) memory space.

The cold rooms even have different sizes. One of the greatest of these is in Meybod. Its double-shell dome is made ​​of raw bricks. To economically and statically to achieve an optimum, the outer shell of the conical dome from bottom to top was thinner. This design had a weight reduction, material saving and also lower your center of balance result. The Meyboder dome is 15m high. The outer shell has a thickness of below 240cm and above 20cm (thickness of a brick ). So the dome reaches a stepped outer wall, which was very helpful in reaching for repair and annual maintenance of this huge building.

Most of the stand, as in Meybod, an approximately 12m high, 40m long and up to 2 m thick (at the bottom) of the Gnomon Wall north of the dome. To the north of this wall the water basin was. For a further reduction and regulation of temperatures most Yakh -chal still have a wind catcher.

The " ice storage " was once connected by a lock-like opening to the pool of water, through which the chunks of ice gained landed for storage in the memory, but which was then walled up again after the "harvest". He also had a most closable entrance through which a narrow staircase led down deep, which served to transport the ice on the opposite side.