Air dehumidifiers for cold rooms

Air dryers for frozen food storage facilities

IR Version
The IR version dehydrators are designed to be installed outside the negative room in an environment with a positive temperature above 5°C (dock, attic, etc.).
For reasons of space saving and ease of maintenance (carrying out equipment maintenance in an environment with a positive temperature), we recommend this installation configuration whenever possible.

ICF Version
ICF versions are intended to be installed inside the negative chamber.

Cold Room Dehumidifiers for Frost and Ice Problems

The storage of frozen products is often a source of problems related to the formation of frost or ice:

• Frozen or slippery floors, difficult and dangerous for personnel;
• Formation of ice leading to premature deterioration, breakdowns and an increase in maintenance costs for equipment and premises;
• Need to repackage products;
• Inability to read barcodes on packaging;
• Increase in refrigeration energy consumption.

This phenomenon comes from the inability of cold air to contain a large quantity of water vapour, which condenses to form fog, frost or ice. For example, in a cold store at -25°C, the maximum quantity of water vapour that a kilogram of air can contain is 0.4 g. Depending on the region, outdoor air in France can reach between 12 and 18 g of water vapour per kilogram of air. An infiltration of outdoor air of 100 m3/h can therefore generate a humidity entry of more than 40 kg per day, which will transform into ice.

To avoid these problems, it is necessary to limit the supply of humidity from outside as much as possible and to dry the air in order to prevent this condensation.

Thanks to the dehumidification systems specifically designed for the DESSICA cold room, very dry air is obtained which allows the required conditions to be maintained in the environment either in the airlock, or in the loading dock, or directly at the access doors of the storage warehouse, thus making this condensation and therefore the formation of fog, frost or ice impossible.

Benefits of Dessica Cold Room Dehumidifier

• Energy consumption:
  • Low energy consumption of DESSICA IR and ICF dehydrators.
  • Reduction in the energy consumption of refrigeration systems due to the spacing of defrosting on the evaporators.
• Reduction in operating costs:
  • No need to remove ice manually in the cold room.
  • Reduction in breakdowns on mechanical equipment (photoelectric cells, palletizers, conveyors, etc.).
  • Low maintenance of DESSICA equipment.
• Reduction in the risk of accidents and improvement of working conditions:
  • The dry floor, without ice on either side of the door, is neither dangerous nor slippery.
• Maintaining the quality of the packaging:
  • No need to repackage products.
  • No difficulty in reading barcodes.

Sizing – Dehumidifier Installation

Each warehouse has a different configuration, so several parameters must be taken into account when sizing the installation:

• the frequency of opening/closing doors,
• the climatic conditions of the room adjoining the negative room,
• The height of the warehouse is also an important parameter because it leads to an increase in the “chimney” effect.

For IR versions (installed outside the negative chamber), the treated air circuit ducts must be insulated on their part located outside the negative chamber and the regeneration air discharge duct must also be insulated. A condensation recovery tray must be placed under the dehydrator if it is installed in an environment with high humidity (> 80%).

Taking these parameters into account, the cold room dehydrator can be supplemented with devices which will limit air entry into the refrigerated storage and thus reduce the supply of water vapour (air curtains, quick-opening doors, strip curtains, airlocks, dehumidification of the adjoining room).

The installation of the dehumidifier for cold rooms is always carried out in the same way by recycling on the air from the refrigerated storage. The cold and humid air is sucked into the negative room at least 4 meters from the door and, after dehydration, blown above the door passage on the negative side. The regeneration air is taken from outside the negative room in an atmosphere above 5°C and discharged outside the building. In the case of an air intake in a lower atmosphere, it will be necessary to provide preheating or tracing of the duct.

For ICF versions (installed inside the negative chamber), the regeneration air circuit ducts must be insulated, isolation valves installed upstream and downstream and an air filter placed at the suction.