The invention relates to a desalination method and system that uses freeze crystallization technology that incorporates the use of compressed air energy as the source for freezing temperatures. When compressed air is released by a turbo expander, chilled air is produced as a by-product, wherein the chilled air is introduced into a chamber, wherein a spray cloud of seawater droplets, which has been pre-chilled by heat exchange with the cold chamber walls, is then circulated and exposed to the chilled air in the chamber. The droplets then settle at the bottom of the chamber, wherein they are deposited at slightly above the eutectic temperature, to form an ice/brine slush mixture. A slush removal mechanism with a screw-like helical blade is provided to continuously remove the ice particles from the chamber.