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When 100% Outdoor Air Dehumidifiers Are Needed

Maintaining proper indoor air quality is essential for ensuring optimal comfort in a variety of applications. Proper ventilation and humidity management must be implemented in a range of environments that involve anyplace that the public have access.

For systems dealing with high-moisture outdoor air loads (naturally humid climates, for example), employing a 100% Outdoor Air (OA) Dehumidifier can help manage required occupant make up air, and the overall quality of the environment. While extremely versatile, these units are most effective when ducted into an existing Air Handling Unit (AHU) or directly into the space at hand as a last resort.

The Basic Types of 100% Outdoor Air Dehumidifiers

The technology available to manage humidity levels in building environments varies nearly as much as the environments themselves; heat-powered active desiccant dehumidification, vapor-compression refrigeration-cycle dehumidification, and exhaust-air/outside-air enthalpy exchange are among the most popular solutions.  They all have a place in conditioning outdoor to the space depending on the dew point and temperature needed in the space.  Occasionally when odors are a problem added dedicated air filtration will be required.

Enthalpy control is the most common measure used in 100% Outdoor Air Dehumidifiers. Enthalpy is a measure of the total energy contained in the entering air.  The permissible level of enthalpy is determined by the level required to be supplied to the air handler or space that is being fed by the dehumidifier.  Enthalpy controlled dehumidifiers are designed to provide maximum air moisture removal and operate at a reduced flow rate when compared to a standard dehumidifier. Air can be supplied from the O/A type dehumidifier at a range of temperatures (or even neutral temperatures, if desired).

At Dehumidifier Corp. of America (DCA), we offer both air-cooled and water-cooled refrigeration based O/A systems.  The air cooled systems are coupled with an outdoor remote condenser. Water cooled dehumidifiers can use  process water, chillers, cooling towers, city water, or geothermal loops to dispose of excess heat generated by the dehumidifier.

Reducing Primary Equipment Size with a DCA O/A Unit

For high-occupant fresh-air loads in spaces such as schools, educational facilities, or large offices, a 100% Outdoor Air Dehumidifier can pretreat fresh air before it’s supplied to the building’s main Air Handling Unit. This allows engineers to reduce the size of the main AHU, as it no longer needs to manage the additional outdoor air loading. The building will only require a unit large enough for its own load, while outdoor air is managed through the dehumidifier and controlled either via enthalpy sensor or modulated reheat for temperature control.

A large indoor pool room is another key example of a high-humidity environment that can benefit from a 100% O/A dehumidifier. Because the outdoor air load from high moisture regions is so highly concentrated, it’s often more practical to split it from the internal required pool water evaporation load usually handled by a recirculating pool dehumidifier. Applying a 100% OA dehumidifier to manage the make-up air can allow for a smaller recirculating air dehumidifier to be used to handle the internal moisture load. The O/A dehumidifier can even be minimized in seasons when the moisture load in the make-up air is lower than that controlled in the pool room. This strategy makes energy usage, run time, and overall loading significantly more efficient.

Dedicated Oudoor Air Systems and Custom Dehumidifier Solutions from DCA

A 100% OA unit can be used in many other applications aside from those discussed above — for example, a DCA unit may be added to an exhaust system along with an energy-recovery device and a heater to create a dedicated outdoor air system. These systems also provide an efficient way to maintain the flow of fresh air to nursing homes, health-care facilities, and any large venue comprised of individual rooms.

Many other practical uses of a DCA O/A system can be applied in a multitude of applications.  Please, contact the factory with your particular needs for assistance.

DCA’s systems rise to the challenge, whether combatting humid outdoor air in warm climates or managing vast amounts of square footage in indoor pools. To learn more about the air-quality management and moisture removal capabilities offered by dehumidifier technology, check out our comprehensive catalog, or reach out to the team today.