Answer: The characteristic that the partial pressure of water vapor in compressed air is determined by the temperature of the compressed air is used for cooling, dehydration and drying. While keeping the compressed air pressure basically unchanged, lowering the temperature of the compressed air can reduce the water vapor content in the compressed air, and the excess water vapor will condense into liquid. The cold dryer uses this principle to dry the compressed air using refrigeration technology, so the cold dryer has a refrigeration system.
