When investing in air compressors for your facility, it is also important to consider what other accessories might be needed along with the compressor & the piping. One of the more common accessories- especially in the Pacific Northwest- is an air dryer. Northwest Pump offers desiccant & refrigerated air dryers through Sullair  and the other air compressor vendors that partner with Northwest Pump. The difference between all the variations of dryers depend on the way they remove moisture. Here are a few points to consider when looking for a compressed air dryer for your system.

Why use a compressed air dryer?

Facilities use dryers of either style to reduce the moisture in the compressed air. Excess moisture can cause problems for the equipment using the compressed air. Depending on the intended use, this moisture could also damage the end-product, reducing its quality or requiring it to be thrown out entirely.

Refrigerated Dryers

Refrigerated dryers work much like a refrigerator in a kitchen does. These dryers reduce the temperature for the compressed air to approximately 35°F, causing the moisture mixed with the air to turn to condensate. The condensate is then stored within the dryer until it gets drained. The dry air then passes through a heat exchanger to be warmed back up before exiting the dryer.

refrigerated compressed air dryerThere are several advantages facilities with refrigerated dryers can expect. First, they tend to be a cheaper investment than other kinds of compressed air dryers. Refrigerated dryers also typically have reduced maintenance costs. However, the cost to operate a refrigerated dryer will vary drastically depending on the ambient temperature around the dryer itself.

Facilities where winter temperatures drop to below freezing should expect to see an increase in costs when using a refrigerated dryer during the winter months. That is because the dewpoint, the point where moisture turns from a gas to a liquid, of the dryer is now higher than the temperature outside. For these reasons, refrigerated dryers are not suitable for installation in areas where temperatures reach 35°F or below. Even if the dryer is installed in a climate controlled area, if the compressed air system’s piping goes outside or is exposed to freezing temperatures, then water will condense in the lines. In this scenario, a desiccant dryer would be needed.

Desiccant Dryers

Desiccant dryers utilize two alternating towers filled with material designed to absorb the moisture in the condensed air. The air travels through a tower, removing moisture, before being sent to the plant. As one tower becomes saturated with moisture the system automatically switches towers until it ‘dries out’ then cycles back.

Desiccant dryers have several ways of maintaining the same air pressure: heatless, heated, and a heated blower purge. Heated desiccant dryers use an additional heat source to help dry the saturated desiccant, which reduces the amount of purge air needed compared to the heatless design. Heated blower purge dryers utilize an ambient air blower in addition to a heater to further reduce the amount of purge air used to achieve the desired pressure dewpoint.

Customers can expect higher initial costs when purchasing a desiccant dryer. Because this type of dryer does not rely on temperature to remove moisture, it costs less to operate annually.

Next Steps

Looking to upgrade your compressed air system? Ask our experts how Sullair’s compressors and dryers can reduce your utility bills here, by calling us at 1-800-452-PUMP, or emailing sales@nwpump.com. Looking for service for your compressors or dryers? Request service here, call us at 1-866-577-2755, or email us at service@nwpump.com.