Standard compressed air enters to the Air to Air heat exchange, where it is pre cooled by out going cold dry air. Highly effective pre cooler reduces the temperature considerably, and enable to use smaller & economical refrigeration system. Then the pre cooled, relatively low temperature compressed air enters to Air to Refrigerant heat exchanger, where it is cooled down to +3°C (Pressure Dew Point). At this temperature, moisture in vapour form condensed to liquid form, and separated from the compressed air by moisture separator and discharged to drain port through automatic drain valve. The cold dry compresses air passes back to Air to Air Heat Exchanger, and gain temperature by exchanging heat with incoming warm air. The dry air coming out from the dryer is ready to use for instrumentation and process air applications.