1) Flow Rate (Free Air Delivery (FAD))
The flow rate is determined by the FAD of your air compressor(s) to determine the minimum flow the refrigerated air dryer needs to be able to process. For example an 8 bar, 75kW Rotary Screw Compressor has a FAD of 14.18m³/min.
2) Operating Pressure
Refrigerated air dryers are usually specified at a 7 bar operating pressure. Therefore a compressor operating at 8 bar would require a correction factor to be applied. The correction factor table below indicates that for 8 bar operating pressure the dryer has a capacity of 1.06 times that of its capacity at 7 bar.
3) Maximum Ambient Temperature The maximum ambient temperature of the environment the refrigerated dryer will be located must be considered in the calculations.
4) Maximum Inlet Air Temperature The inlet air temperature refers to the temperature of the compressed air as it enters the dryer. An effective aftercooler will reduce the temperature of the compressed air to around 10°C above ambient. An air dryer selected for an ambient temperature of 35°C will typically experience an inlet temperature of 45°C.
5) Pressure Dew Point
The pressure dew point is the point at which water vapour turns to liquid. A correctly sized dryer will lower the pressure dewpoint such that moisture is turned to liquid which can be easily removed.