Cold trap

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A cold trap is a natural or artificial cave that is built in such a way that ice accumulates or can be brought into the deepest part. It uses the physical property that cold air is heavier than warm air and that air itself is a poor conductor of heat.

The air lying above the ice cools down to the ice temperature, which makes it heavier than the warm outside air and thus shields the cold medium from the warm. If it is immovable over the ice, i.e. there is no convection , there is only a slight warming of the ice through heat exchange and heat supply through the walls.

Before the invention of the refrigerator, cold traps were used to preserve food and to cool beer ( ice cellar ).

A natural cold trap is located in the Wendelstein cave below the Wendelstein . Ice can be found in it well into summer; the temperature is - as long as there is ice - at 0 ° C. The Birresborn ice caves in the Eifel, which were created by the quarrying of millstones, represent a cold trap created by human hands (probably unintentionally) .

A cold trap catches the cold in a small space and should not be confused with a cold trap , which uses cooling to separate substances from mixtures of substances, e.g. B. for drying humid air, which is passed through coiled pipes through which liquid nitrogen (-196 ° C) flows.

Individual evidence

  1. Birresborn Ice Caves. Retrieved August 25, 2019 .