condensation and frost prevention

When cold surfaces are surrounded by moist air, water vapor will condense on the surface if the dew point of the surface is lower than the dew point of the surrounding air.

This phenomenon, known as “sweating,” often leads to corrosion such as in water treatment plants or during surface preparation and coating of storage tanks in the chemical industry.  Additional problems can be caused when moisture condenses on ice rink surfaces and softens the ice.  Finally, injection molding machines often use chilled water to remove the heat from the plastic during forming. Condensation can form on the molds causing disruption in the molding process.

Bry-Air’s desiccant dehumidifiers are used to blanket the surface with dry air resulting in condensation prevention and economic benefits to the end user.

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Condensation Prevention in the Meat Industry

Unwanted moisture is a problem in nearly all meat processing plants throughout the world. Dangerous conditions, such as fogging, are the results of unwanted moisture forming on equipment, floors, ceiling, and walls. Condensation happens in meat and poultry processing plants when warm humid air comes in contact with cooler surfaces such as those found in cut rooms, chiller rooms and packaging rooms.

Increased scrutiny by the USDA has resulted in companies actively searching for cost-effective solutions for fogging, icing, dripping, and other moisture related problems in order to comply with the USDA zero tolerance guidelines.

Condensation is the problem, and desiccant dehumidification is the solution. Bry-Air, Inc. desiccant dehumidifiers precisely control the humidity and dew point in the plant so that condensation cannot occur. Contact Bry-Air toll free at 877-427-9247 to see how we can assist you with your facility needs. 

Design & Implementation of Desiccant Dehumidification MUA System for the Food Processing Industry

ConAgra partnered with Bry-Air, Inc. to solve process environment issues at their plant in Jonesboro, Arkansas. The 80,000 sq ft plant provides deli-quality turkey products. The operational issues ConAgra and Bry-Air, Inc. agreed to address included:
  • High humidity levels in the plant which caused continuous condensation issues.
  • Severe negative pressures in the process areas.
  • Process area temperatures that were near the limit of allowable specifications.

The first phase of the project involved an in-depth study of the plant processes and existing conditions. This included identifying all air systems, air flow patterns, current plant operation models, wash down and refrigeration system.  From this in-depth analysis a plan was put together to address the issues. The plan included adding desiccant DH MUA systems, chillers, ductwork, utilities and modifying existing MUA systems, exhaust systems and air movement devices.The plan was implemented by ConAgra using purchased desiccant DH systems, rental chillers and local contractors for electrical, piping, duct work, roofing and rigging. Bry-Air, Inc. provided design, support, supervision, start-up and commissioning of the systems.  At the conclusion of our work, the following results were achieved:

  • Humidity levels are being maintained well below condensation dew points at all ambient conditions.
  • Process space temperatures have been lowered 5-10 degrees because of frost reduction on the refrigeration coils.
  • Defrost cycles have been reduced by 50-70% and in some cases were be completely eliminated.
  • The process space is maintained with sufficient positive pressure to minimize or eliminate moisture and thermal infiltration
  • Internal process space air flow patterns are correct for proper cleanliness and quality requirements.
  • Wash-down dry-out is significantly quicker and less labor intensive.conagra_case_study_meat_processing
  • Process exhaust has been reduced by 60% with no negative effects on process quality.
  • Floors dry quickly and stay dry during daily process cycle.
  • Building structure has been dried out. Concrete is dry as is the roof structure.

The Jonesboro facility’s problems were solved and all compliances were achieved.

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Dehumidification Control System for Mold & Fungus Prevention in the Brewing Industry

dehumidification_in_breweriesBry-Air, Inc. environmental control systems allow for consistent and quality products to be produced efficiently by preventing the effects of humidity.  Brewing requires large amounts of heat, water and malted grain. All of these components are necessary for growing yeast which turns natural sugars into alcohol. In a brewery yeast is a beneficial fungus, however if ambient humidity levels remain unchecked, microbes and fungus may grow in its place and disrupt the brewing process.

Hygiene is an inherent problem in any brewery or distillery. The growth of mold and fungus on walls, in the hops storage area and in the fermentation and yeast rooms is caused by one common factor…humidity.

The following are general guidelines for temperature and humidity control in breweries:
Area Temp ° F % RH
Hops Storage 35 45% – 55%
Fermentation Rooms 55 – 65 40% – 45%
Filtration Rooms 55 – 60 40% – 45%
Grains Storage 60 35% – 40%
Kegging Areas 55 – 60 40% – 45%

The brewing process requires very low temperatures which can result in condensation on the tanks and vats containing the beer. In addition the presence of high humidity due to frequent water usage for cleaning make conditions perfect for condensation and growth of bacteria. Desiccant dehumidification can eliminate organic corrosion, mold, mildew and fungus in yeast rooms, fermentation rooms, storage facilities and kegging areas. Other benefits of dehumidification include improved sanitary conditions, reduced maintenance costs, frost free operation and quicker drying of floors after washing.

Heineken, the Dutch beer brewer, is famous all over the world and needs no introduction. Maintaining high quality in all aspects of the production of beer is of prime importance to all Heineken employees. So when they had problems with condensation, bacteria and sanitary conditions within their production area they contacted Bry-Air, Inc.

The total moisture load at a temperature of 35°F was 224 pounds of water removal per hour. To remove this quantity of water a Bry-Air, Inc. Model MVB-200-FS was selected with a nominal airflow of slightly over 20,000 cfm. The energy source for the reactivation was steam and an air-to-air heat recovery coil was included for additional energy savings. The dehumidifier was installed on the roof of a six floor production building in a sheet-metal housing. From there the dry air was distributed to each of the six floors and the basement area. The return air from the production areas was re-circulated through the dryer and dried on a continuous basis.

With Bry-Air’s expertise, derived from over 50 years of experience, Heineken to solve their hygiene problems and continued to produce one of the world’s highest quality beers.

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Environmental Temperature Control Systems for Storage Silos


dehumidification_of_silosBry-Air, Inc. environmental control systems allow for consistent and quality products to be produced efficiently by preventing the effects of humidity.

When material is stored in a silo there is usually a “dead space” or open area at the top which is left open for air circulation. This empty space can create problems because the variation of temperatures outside the silo will result in condensation in this space. This condensation forms on the walls and can lead to the following problems:

  • Corrosion of the silo itself.
  • Caking and agglomeration of hygroscopic material stored inside.
  • An increase in microbial activity leading to the spoilage or contamination of the material being stored.
  • Some chemicals can become hazardous when exposed to water.

The fact that such large quantities of product are stored in silos makes the spoilage or contamination of that product a very expensive commercial loss. In the past, the traditional method of moisture prevention was the use of pressurized hot air which was blown up from the bottom of the silo. This is an effective method but the energy costs to accomplish this can far exceed the benefits. In addition, if the material being stored is powdery or the bulk density is very light, the product tends to become airborne within the silo which can lead to physical degradation of the material known as “flake off”.

The Bry-Air, Inc. desiccant dehumidifier is designed to provide dry air continuously and without the high temperatures that could cause damage to the product. Regardless of ambient conditions, the Bry-Air, Inc. dehumidifier provides dry air inside the silo that is below the dew point of the air outside the silo, thereby eliminating any condensation and the problems associated with condensation.

Another advantage in using desiccant dehumidification is that the dehumidification can be accomplished with a small, energy efficient dehumidifier. Therefore, there are no problems with bulky equipment and high energy bills. Depending on the customer’s preference, the Bry-Air, Inc. unit can be placed next to the silo or mounted on a catwalk. If desired, multiple silos can be fed from a single dryer in a central drying arrangement or smaller “dedicated” units can be utilized on each individual silo.


  • The dehumidifier should be sized to deliver 100% fresh air in an amount equal to at least one air change per hour based on an empty silo. The total volume of the silo divided by 60 indicates the minimum CFM.
  • For low dew point applications, when hygroscopic products could be subject to significant moisture regain, or when interior to exterior temperature differences are more extreme, it is preferable that the fresh air be pre-cooled by chilled water or DX, before dehumidification.
  • If the dehumidification system is designed to re-circulate the silo air, additional filtration may become necessary.
  • Care should be taken to prevent product dust from entering the dehumidifier from back pressure when filling the silo or when returning product back to the silo.

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Condensation Prevention Control Systems for Ice Skating Arenas

ice_skating_arenasBry-Air, Inc. environmental control systems allow for consistent control to efficiently prevent the effects of humidity.  According to the physical laws of nature, moisture migrates through the air from a higher concentration to the lower concentration due to a difference in vapor pressure. When air is cooled it is not able to hold as much moisture. Thus, moisture will condense on any surface that has a lower temperature than the dew point temperature of the air.

This is particularly a problem in ice arenas where the condensed moisture is deposited onto the surface of the ice in the form of water droplets and also, in the form of fog above the surface of the ice. When moisture condenses and accumulates on the surface on the ice, it is known as “frosting”. This “frosting” in turn, results in “slow” ice and also imposes an additional load on the ice making system.

These conditions cannot be solved by ventilation because the introduction of outside air only aggravates the problem when the weather outside is mild and humid. Insulating the roof also aggravates drip during mild outside weather conditions. Low emissivity ceilings stay warmer and thus, reduce condensation and dripping. Under these conditions, to prevent condensation in the ceiling space and to eliminate the fogging, there are two approaches; refrigeration or desiccant dehumidification.


In the past, refrigeration air conditioning systems, utilized in ice skating, curling and hockey rinks, have had a history of humidity related problems along with high energy consumption rates. Conventional refrigeration equipment can maintain space conditions in a skating rink of 45°F to 60°F at a relative humidity of 60% to 75%. This can result in the air so close to saturation that it actually forms a fog over the rink and condensation inside the building and on the surface of the ice.
Any attempt to maintain lower humidity levels would necessitate maintaining evaporator temperatures lower than 32°F which would result in frost formation on the evaporator coil. A more effective and energy efficient solution is a desiccant dehumidification system.


The primary advantage for a desiccant dehumidification system is its ability to dry air down to very low humidity levels. A desiccant dehumidifier can easily maintain 30% to 40% relative humidity within an ice skating rink thus, eliminating fog and condensation year-round, regardless of outdoor weather conditions.

According to studies conducted by ASHRAE and several manufacturers of desiccant systems, the average energy consumption of a desiccant dehumidifier is as much as 70% less than a comparable refrigeration system. So, desiccant dehumidification systems can eliminate fog and condensation while, at the same time, reducing operating costs. There is also the potential for a reduction in maintenance to the building and equipment inside as it is no longer subject to excessive humidity and the problems associated with it.

To Download a PDF version of this case study click HERE.