The calculator answers the two questions that every dryer selection starts with: how much water enters the system along with the compressed air, and what rated capacity the dryer needs under the conditions in your compressor room. The results are indicative and serve as a first check of your assumptions before you talk to a supplier.
Estimate how much condensate forms in your system and convert a dryer's rated capacity to your actual operating conditions.
Compressor and system parameters
Flow referenced to inlet conditions
Maximum value, not the annual average
Humidity of the intake air
Pressure in the distribution system
Value from the dryer datasheet
Actual compressor running time
Reference conditions ISO 7183 defines the reference conditions for refrigeration dryers: 7 bar working pressure, +25 °C ambient temperature and +35 °C inlet air temperature. Catalogue capacities refer to these conditions.
System requirements
Peak flow, not the average
Coldest section, winter included
Set by the process or customer specification
Correction factors from the datasheet
Read factors K1-K4 from the datasheet of the specific dryer. They differ between manufacturers and models, so the calculator does not assume them. With the default value of 1.00 the result reflects the reference conditions, not your actual installation.
This calculator is an indicative tool and does not replace sizing based on the equipment datasheet and complete system data. Results rely on the ideal gas model and the Magnus formula for saturation vapour pressure. The actual condensate load varies with ambient conditions and aftercooler performance.
Factors K1-K4 are not universal. Every manufacturer publishes its own values in the datasheet, separately for working pressure, inlet air temperature, ambient temperature and required dew point. This is why the calculator does not assume them – with the default value of 1.00 the result reflects the reference conditions, not the conditions in your own installation.
A full explanation of these parameters, a comparison of drying methods and a step-by-step selection procedure are covered in our article on compressed air drying in industry. The available units are listed in the compressed air dryers and air treatment category.
To confirm the result for a specific installation, send the parameters above to a CPP PREMA technical advisor. They can recalculate the capacity using the manufacturer’s correction factors and select the filtration and condensate drainage to match.
