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How to size a dryer

Compressed air dryer capacity is rated by standard cubic feet per minute (SCFM) capacity, operating pressure, and the dew point range. The right dryer for your system is dependent on a few variables; most industrial applications require common refrigeration dryers, while larger more sophisticated applications that operate within tight tolerances or controlled environments are more suitable for desiccant dryers.

Keep in mind, standard rating is based on 100ᵒF saturated inlet air temperature and 100 PSIG operating pressure. It is important to evaluate the actual performance of the units in their intended operating conditions.

Sizing Guideline

  1. Choose a unit that is rated with a higher maximum air flow (SCFM) than what your compressor can deliver. An undersized dryer will run inefficiently and produce a substantial pressure drop, as the air will have trouble passing through, and to compensate you will have to set your compressor’s pressure higher. Higher pressure settings can result in more energy consumption and inability to deliver the dew point required for your application.
  2. Keep maximum pressure in mind, as you will want to choose a dryer that matches or exceeds the pressure rating of your compressor.
  3. Evaluate ambient temperature for where the dryer is to be placed. You will need to select dryer to be able to handle its operating environment.
  4. Check the maximum inlet air temperature of the unit and make sure your inlet air temperature does not exceed the maximum. If you determine the air coming out of your compressor is too hot for the unit, there are accessories available that are designed specifically for additional cooling.

Modern industrial applications require the highest quality air, including, but not limited to applications such as pneumatic automation, electronics, pharmaceutical and food industries. Compressed air that might be sufficiently dry for one application, might not meet the requirements for another.

Although an undersized compressed air dryer will cost less to buy initially, the dryer will be running at full load capacity, resulting in higher operating costs and energy use. Even then, you may have trouble maintaining a constant dew point leading to inconsistencies or variations in the dryness of the compressed air. A correctly sized and installed unit provides long term, trouble free operation.

Unsure about the unit you need for your compressed air unit requirements? We are here to help you. Be prepared with the following information and call or email one of our customer service reps for assistance and product selection.

  • SCFM Flow (Standard Cubic Feet per Minute)
  • Dew Point
  • Operating Pressure
  • Inlet Air Temperature
  • Relative Humidity
  • Compressed Air System Type
  • Voltage