Silo Dehumidification / Hot Air Dryers
By Mark Haynie and Joshua Belisle · Edited by Dana Gardner
Published August 9, 2024 · Reviewed by Mark Haynie · June 15, 2026
Summary
What does a silo dehumidifier do for stored resin?
A silo dehumidifier keeps stored resin from picking up moisture; it does not dry the material. Metal silos sweat internally as outdoor humidity and temperature change, and that moisture can transfer to the resin. The dehumidifier circulates silo air through a desiccant, typically silica gel or molecular sieve, and returns a blanket of dry air to the space above the material.
[Airflow 150-250 cfm]
Metal silos are affected by the weather conditions surrounding them. They can become damp internally from sweat on their sidewalls caused by changes in humidity and temperature. This moisture can be transferred to the material stored in the silo.
Silo dehumidifiers are not intended to dry the material stored inside the silo. Instead, they operate on the simple principle of providing a blanket of dry air in the space above the material to keep the material from picking up additional moisture while in storage.
Silo dehumidifiers are usually installed in the base of a silo and one dehumidifier may serve more than one silo.
A resin silo dehumidifier is a device used to remove moisture from the air inside a resin silo. The dehumidifier works by using a desiccant material to absorb moisture from the air.
The dehumidifier consists of a housing unit that contains the desiccant material, which is typically a silica gel or molecular sieve. The housing unit also contains a fan that circulates the air inside the silo through the desiccant material.
As the air passes through the desiccant material, the moisture in the air is absorbed by the desiccant, leaving the air dry. The dry air is then released back into the silo, helping to maintain the desired humidity level.
5 Tips for Choosing a Resin Silo Dehumidification System
- Capacity: Choose a dehumidifier that is appropriate for the size of your resin silo. The dehumidifier should be able to handle the volume of air in the silo and maintain the desired humidity level.
- Efficiency: Look for a dehumidifier that is energy efficient, as this will help you save on energy costs in the long run. Check the dehumidifier’s energy consumption and compare it to similar models to find the most efficient option.
- Durability: Choose a dehumidifier that is built to last. Look for a model with a sturdy construction and quality components that can withstand the harsh conditions often found in industrial environments.
- Maintenance: Consider the ease of maintenance when choosing a dehumidifier. Look for a model that is easy to clean and has easily accessible components that can be replaced if necessary.
- Features: Consider any additional features that may be useful for your specific needs. For example, some dehumidifiers may come with a digital control panel, automatic shut-off, or the ability to adjust the humidity level. Choose a model with features that will make it easier for you to use and maintain the dehumidifier.
Types of Resin Drying Systems
Silo Dehumidification/ Hot Air Dryers
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Frequently Asked Questions
Why does resin in a metal silo pick up moisture?
Metal silos respond to the weather around them. Changes in humidity and temperature cause sweat to form on the inside of the sidewalls, and that moisture can transfer to the material stored in the silo. A dehumidifier counters this by keeping the air above the material dry so the resin does not absorb additional moisture in storage.
Can one silo dehumidifier serve more than one silo?
Yes. Silo dehumidifiers are usually installed in the base of a silo, and one dehumidifier may serve more than one silo. The unit houses the desiccant and a fan that circulates the silo air through it; the dried air is released back into the silo to hold the desired humidity level. Airflow for this class of equipment is in the 150-250 cfm range.
What should I look for when choosing a silo dehumidification system?
Five things: capacity matched to the volume of air in the silo so it can hold the target humidity; energy efficiency, compared against similar models; durable construction that stands up to industrial conditions; easy maintenance with accessible, replaceable components and simple cleaning; and features such as a digital control panel, automatic shut-off, or an adjustable humidity setting.
About the Authors
Vice President of Moisture & Drying Technologies, Novatec
Mark Haynie has designed and installed resin drying systems for more than 40 years, working in thousands of plastics plants across the industry. As Novatec’s Vice President of Moisture & Drying Technologies, he leads the company’s drying technology group, including its work on moisture measurement and predictive drying. He also serves as a technical reviewer for Novatec’s Drying Knowledge Center and has authored numerous technical articles and whitepapers on resin drying and moisture.
Mark earned a Bachelor of Science in Chemical Engineering from Virginia Tech.
Through Novatec’s Ask the Expert program, Mark regularly helps processors troubleshoot drying performance and resin-moisture challenges.
Technology Manager, Novatec
Joshua Belisle is Technology Manager at Novatec, where his work focuses on simulation and technology development for resin drying. He earned a B.S. in Mechanical Engineering with a minor in Engineering Business from the University of Virginia in 2023 and joined Novatec that same year. Joshua uses simulation tools to investigate previously difficult-to-measure aspects of the drying process, helping Novatec better understand airflow, heat transfer and other variables that influence resin-drying performance.
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Author Profile:
Mark has designed and installed resin drying systems for more than 40 years, working in thousands of plastics plants across the industry. He leads Novatec’s drying technology group, including its work on moisture measurement and predictive drying, and serves as the technical reviewer for the drying articles in the Knowledge Center. He has authored numerous technical articles and whitepapers on resin drying and moisture, including How to Optimize Resin Drying in Humid Weather, and answers processors’ drying questions through the Knowledge Center’s Ask the Expert program.