Compressed air dryer sizing basics

When completing your air treatment setup, it's important to understand how compressed air dryer sizing and type impact air quality.

When completing your air treatment setup, it's important to understand how compressed air dryer sizing and type impact air quality. Since high temperatures create more moisture (water vapor), you'll want to pay attention to actual cubic feet per minute (acfm). This is opposed to standard cubic feet per minute (scfm).

The reason why this distinction is essential is how both ambient heat and generated heat impact water vapor levels. Actual cubic feet per minute accounts for this. When following guidelines for proper compressed air dryer sizing and type, you'll protect your equipment and end product. This is because untreated moisture can contain microorganisms as well as lead to rust and other air compressor maintenance issues.

This article covers both compressed air dryer sizing and type for your desired application. It provides a general overview of how to assess what's more appropriate for your environment and industry.

Person formulating dimensions for air compressor

Additional factors for compressed air dryer sizing

In addition to what's mentioned above, there are several factors you need to consider when sizing an air compressor dryer. These include inlet air pressure and flow, inlet air temperature, ambient air temperature, relative humidity, as well as pressure dew point (PDP). The latter will determine the type of dryer you need, typically either a desiccant or refrigerant. These will be covered later.

Essentially, you want to ensure that your dryer can handle the flow (expressed in cfm) of your air compressor, along with drying capacity and operating conditions. If you work in a hot, humid environment, you'll need equipment to compensate for that in addition to handling the compressor's flow rate. With all this, the inlet temperature determines the water load. These points are really important for lowering the PDP or drying the air.

That being said, much like sizing an air compressor, you don't want to invest in a machine that's either too big or too small. In either instance, you'll run into extra costs and unnecessary performance issues. Typically a compressed air dryer is rated based on standard psig, inlet temperature, and ambient temperature levels.

If your environment/operations deviate, then it's important to determine actual capacity with the manufacturer's guidelines.


Air compressor dryer types

As mentioned above, there are generally two types of air compressor dryers. These are either desiccant or refrigerated. With this, it's worth pointing out that refrigeration dryers are acceptable for most industrial applications. However, if you work in a sensitive industry, like medicine or food and beverage, then a desiccant dryer is usually needed.

Refrigerated air dryers provide a dew point of 3° Celsius (37° Fahrenheit). By comparison, desiccant dryers achieve up to -70 °C (-100 °F) as standard. This low temperature delivers clean, dry air. Of course, to know what's most suitable for your application, you'll want to consult the International Organization for Standardization (ISO) 8573-1 air quality classes.

It's also worth pointing out that for particularly sensitive applications, an oil-free air compressor is recommended. This is because oil-injected equipment uses oil as a lubricant and coolant. Drying and filtering won't remove all oil microparticles from water vapor. You can find related articles on these topics on our blog.

Choosing the right air treatment setup

While this article provides a general overview of compressed air dryer sizing, we hope it helps point you in the right direction. Of course, it's always advised to consult an expert when making such decisions for your business.

In addition to dryers, you'll also want to add aftercoolers, pipes, filters, separators, and drains. A comprehensive air treatment setup is essential for any industry. This also applies to handling waste after moisture is removed from your oil-injected equipment.

To make this more clear, you'll want to adhere to environmental and governmental regulations surrounding waste disposal to keep your operations in good order. If you have any questions on these topics, our team is available to help point you in the right direction.

Contact us today for an assessment of your needs. We're happy to help design the right air treatment solution.