Mechanical Dehumidifiers use refrigeration components to lower the dew point of air to prevent undesirable condensing or sweating on machine surfaces. Designed for use in the plastics industry, Berg’s Dehumidifiers shower a production area with dried air preventing moist plant air from condensing on cool or cold mould surfaces.

Since the ability of air to hold moisture decreases with decreasing temperature, the moisture in the air condenses as it passes through a cooling coil. Condensate collects on the cold coil surface and is then drained away and dryer cool air remains. The air then passes through a reheat coil to bring it back to ambient temperature or above and is then force into the moulding chamber.

The Mechanical Dehumidifying units can easily achieve dew point temperatures of 40-45°F, which allow cooled surfaces in the process area to operate at temperatures above this without fear of condensing moisture.

Occasionally processes require air at dew point temperatures below freezing. In these instances we incorporate the use of desiccant air driers to remove the moisture to these low levels. The packaged unit would first achieve the bulk of the drying with the refrigeration equipment and then the desiccant would be used to trim the remaining moisture from the air.

A desiccant is an hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container. Commonly encountered pre-packaged desiccants are solids, and work through absorption or adsorption of water, or a combination of the two.      Desiccants for specialised purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules. Pre-packaged desiccant is most commonly used to remove humidity that would normally degrade or even destroy products sensitive to moisture.

Silica gel, calcium sulfate, calcium chloride, montmorillonite clay, and molecular sieves are commonly used as desiccants. Rice is a common "low-tech" alternative, frequently used for example in salt-shakers to maintain granularity of table-salt for effective pouring or shaking.        Rice, however, is not a good general purpose desiccant since, unless immersed in an organism-hostile environment like pure salt, over time may be eaten by creatures that might in turn pollute the product that is being preserved. Salt itself is another effective desiccant, used for millennia in preparation of dried foodstuffs.