VISION ISSUE SEVENTEEN | SUMMER 2024
The Role of Adiabatic Humidification in MEP Design Introduction to Humidity Control Humidity control is a key factor within the MEP industry that can heavily dictate which heating and cooling systems are implemented within a building. The majority of variable air volume (VAV) systems are required to remove moisture from the supply airstream in the air handling unit. This is done through the cooling coil, which cools the air and wrings out moisture into the condensate drain. A reheat coil will raise the temperature back to the desired setpoint, where the resultant indoor space relative humidity falls within a typical range of 45-60%.
the air through several high-pressure spray nozzles. These nozzles are arranged perpendicular to the flow of air, spraying water into the media. Hot air travels into the adiabatic section, then cool water is
Certain projects require moisture and humidity control year-round, due to factors such as geographical location or program type. During the winter, when outdoor air humidity is generally low, critical building spaces such as museums or libraries will need additional moisture in the airstream to maintain a constant relative humidity setpoint.
sprayed and evaporated into the system. While this process increases relative humidity in the airstream, it cools down the air at the discharge once the energy has been used to evaporate the water.
What is Adiabatic Humidification? To humidify a space, moisture needs to enter the airstream in a gaseous state. Utilizing steam is a common method of humidification, which is an isothermal process. Boilers or heat exchangers are required to generate steam that will be mixed into the system at the air handling unit. In order to create that vapor form from a liquid, 1,000 BTUs per pound of water are required. While 1,000 BTUs per pound of water are still needed, adiabatic humidification is an alternative process that does not require any creation of heat. Energy is drawn from the surrounding atmosphere, turning water into vapor and humidifying the air. Atomized water is introduced into
cleaner method of generating humidity. Adiabatic systems can also contribute to a project’s overall goal to provide an allelectric humidification option, reduce carbon emissions, and provide an energy
Image 1: Adiabatic Humidification Flow Diagram
Pros: Energy Efficiency, Reduced Carbon Emissions, Ease of Maintenance, and Cost Savings If an owner or engineer is implementing a central humidification system into their building, she might consider adiabatic humidification for the simple reason that steam is not readily available. If there is no central plant to produce steam, or it becomes too costly to install a steam boiler, then utilizing adiabatic humidification is a reasonable alternative. Steam boilers that use natural gas and/ or oil will not only waste fossil fuels but create greenhouse gas emissions and contribute to ozone depletion. Nozzle spray humidification naturally absorbs moisture from the atmosphere without having to generate additional humidity. The energy savings accrued from this process will save owners money over time, while also ushering in a ALL TEXT ©2024 KOHLER RONAN, LLC
efficient solution in terms of operating cost and lower input kW per humidification capacity. The high-pressure spray system is relatively easy to install, comprised of only a grid of nozzles that are fixed into the air handling unit. High-pressure pump skids transfer treated water from the reverse osmosis (RO) filter and water treatment system to the manifold in the air handling units; inlet water is connected to the main domestic cold-water line. The system requires semiannual and annual maintenance, including salt maintenance, nozzle cleaning, and maintenance of the water treatment system. Adiabatic systems require minimal “The Role of Adiabatic continued on page 2
Humidification…”
IN THIS ISSUE The Role of Adiabatic Humidification in MEP Design
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Revit ® Corner 3 Project Highlight
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