Since its invention in the 1950’s, the use of desiccant dehumidifiers has grown dramatically. The growth is attributed to the desiccant dehumidifier’s ability to achieve and effectively maintain lower humidity levels compared to refrigerant style dehumidifiers. Now, a wide variety of industries use desiccant dehumidification to improve the quality of their processes and products. In this article, I will discuss some of the many applications for desiccant dehumidifiers.
Corrosion Prevention
All materials corrode, which is to say every substance eventually changes from one form to another through chemical reactions. Moisture can catalyze and accelerate chemical reactions that depend on oxygen and heat. Desiccant dehumidifiers work to protect materials from subtle and expensive forms of corrosion by removing moisture that may come in contact with the material surface. Some of the applications where desiccant dehumidifiers are used for corrosion prevention are:
- Marine vessel storage and lay-up
- Lithium battery production
- Computer and electronics protection
- Ammunition storage
- Military and civil avionics protection
- Box beam and metal tank protection
Condensation Prevention
When cold surfaces are surrounded by moist air, water vapor will condense on the surface like “sweat” on a cold beer glass in summertime. This can lead to a surprising number of problems. For instance, consumers in a supermarket may not be able to see frozen foods in a refrigerated display case with a glass door. That may mean thousands of dollars in lost revenue. Alternately, condensation can form on hidden aircraft structural members as a plane descends from the cold upper atmosphere into moist environments, which can accelerate stress corrosion, shortening the life of the air frame. In both of these cases, dehumidifiers are installed to surround the cold surface with dry air. Typical applications for condensation prevention include:
- Cold and frozen product storage
- Ice rinks
- Surface preparation and coating
- Injection molding
- Aircraft interiors
Mold and Fungus Prevention
Mold and fungus are present in almost all materials. They can survive without moisture, remaining dormant for decades, even centuries. But when moisture and a food source become available, they will multiply rapidly. Desiccant dehumidifiers help prevent mold and fungus growth by reducing the amount of moisture in the air. Mold and fungus prevention applications are:
- Grain, seed and bulb storage
- Food and meat production
- Wine and beer production and storage
- Archives, libraries and museums
- Fabric and textile manufacturing and storage
Moisture Regain Prevention
Virtually every substance has some affinity for moisture. Even plastic resins like nylon cans collect six to ten percent of their dry weight in water vapor. For some products, moisture regain can affect critical dimensions just like thermal expansion or can make products that would otherwise flow freely stick together. Desiccant dehumidifiers are effective in controlling humidity at low temperatures, and have been widely applied to prevent moisture regain in these applications:
- Fertilizer packaging and storage
- Flour, plastic and powder conveying
- Sugar and powdered drink packaging
- Semiconductor manufacturing
- Pill manufacturing and packaging
Product Drying
Most products are dried using hot air to vaporize moisture and carry it away. Often, hot air is either too slow or results in damage to the product. Using a desiccant dehumidifier for product drying can maintain product quality without sacrificing processing speed. Because of that, the range of product drying applications for desiccant dehumidifiers has expanded significantly in recent years to include:
- Meat, fish, pasta, cheese and vegetable cooking
- Plastic, nylon and polystyrene production
- Chromatography materials
- Pharmaceutical and food powders
Dry Cooling
Air conditioning systems generally use cooling coils to control both air temperature and humidity. In most comfort-conditioning applications, this is an extremely efficient method of controlling humidity. In some circumstances, there is a benefit to adding a desiccant dehumidifier to the cooling system to control humidity separately from air temperature. The benefits are greatest where the moisture loads are high compared to the sensible heat loads, or where they peak at different times. For example, a building may be able to use 65°F outside air for cooling, but the air will still be carrying enough moisture to require dehumidification. Applications for dry cooling include:
- Hospitals and nursing homes
- Hotels and health clubs
- Supermarkets and retail stores
- Public building and auditoriums
Short-Term and Long-Term Solutions
Whether your application requires a desiccant dehumidifier for a week or on a permanent basis, Eldridge can recommend the right sized unit to fit your needs and time period. For short-term needs, we have partnered with Industrial Drying Solutions to provide rental units with turn-key installation and service. For permanent applications, we offer the complete line of desiccant dehumidifiers from Innovative Air Technologies.