Compressed air chiller dryers are one of the most important parts of compressed air system. No matter where you are, in tropics or in desert, atmospheric air contains some water vapour. When the air or gas cools to the point where it can hold no more water vapour (past the saturation point), it will start to condense into liquid water. This happens at the temperature called the dew point. This dew point is a kind of measure, how much compressed air drying is needed. 

Dry air is important. In almost every process, clean and dry compressed air will result in lower operating costs. Impurities such as solid particles, water and oil, which are in the air will be deposited on the inner surfaces of pipes fittings and inner components, causing an increase in pressure drop. 

The result is undesired loss of performance efficiency. Types: (High pressure) Heatless desiccant regenerated adsorption dryers, Membrane compressed air chillerdryers, Refrigerant compressed air chiller dryers, Heat regenerated adsorption dryers.