Gem Air Dryer 400 CFM, Refrigerated Air Dryer For greater air drying capacity, we offer refrigerated air dryers with air capacities typically above 500 NM3/h. This is a skid-mounted unit consisting of an air-to-freon cooler, an air-to-air precooler, and a moisture separator. The air is first pre-cooled to about 25C with cold air and then cooled to a temperature of (+)3C in a Freon cooler, thus reducing power consumption. The discharged dry air has a dew point of (+)3C and is discharged at a temperature of approximately 25C as a dew point of (+)3C corresponds to a dew point of approximately (-)25C at atmospheric pressure will be pressure.