A freeze type compressed air dryer machine uses refrigeration to cool compressed air, causing moisture to condense into liquid water, which is then removed. It is a common and cost-effective method for dehumidifying compressed air to prevent issues like freezing, corrosion, and equipment damage in pneumatic systems. The process involves a refrigeration cycle with a compressor, condenser, evaporator, and expansion valve that cools the air stream, removes liquid water, and then reheats the air slightly to prevent re-condensation.