The humidifier you select for your commercial project matters. The type of humidifier you choose and the installation logistics involved will significantly affect everything from air quality to OSHA compliance, so you must correctly determine the right humidifier for optimal commercial air management.
A commercial humidification system allows you to increase or decrease humidity levels for industrial, healthcare, education, and other public environments. While most buildings have heating, cooling, and ventilation systems, only a fraction have a humidification system. This is a significant oversight in commercial air quality management because optimal air moisture offers a variety of benefits, including the following:
- Health: Low relative humidity indoors contributes to higher rates of infection by airborne-transmitted diseases, as well as increased respiratory problems.
- OSHA Compliance: OSHA dictates the acceptable range of indoor humidity is 20–60%.
- Energy Efficiency: The expense of a humidifier can be offset by minimizing heating costs, damage to equipment, adverse health issues, and related costs (absenteeism, insurance claims, and more).
- Commodity Protection: Commercial environments, such as warehouses and laboratories, need to control humidity within a 5–10% range of setpoint to protect goods and other commodities.
- Static Electricity Reduction: Static electricity can damage electronics and is unsafe in the presence of hazardous or explosive materials.
Two Types of Humidifiers for Commercial Air Management
Engineers usually choose from two types of humidifiers; isothermal or adiabatic. Each offers advantages and challenges.
Isothermal Humidification
In this system, external thermal energy produces vapor or steam. Air temperature remains nearly constant. This system offers exact control of humidity and doesn’t increase heat load space. It’s also an exceptionally hygienic system (medium is above 212° F, or 100° C). However, an isothermal humification system does require an outside heat source such as steam, hot water, electricity, or gas.
Adiabatic Humidification
In this system, water (as opposed to steam) is introduced into the air. Space air or airflow provides the energy for vaporization. No heat is added from an external source.
An adiabatic humidification system may offset the cooling load, particularly in shoulder seasons, resulting in energy savings. This system also offers precise humidity control and is a good option when steam or gas is unavailable. However, more extended air handling units (AHUs) are potentially needed due to longer absorption distances. In some applications, additional heating capacity might be required.
Where Will You Install Your Humidifier?
There are two locations to install a commercial humidifier. A ducted humidifier is the most common installation. In this configuration, vapor is distributed via the ductwork. That vapor can be produced either inside or outside the ducts. This system is popular because it doesn’t interfere with the existing layout, and it can utilize existing fans and heating systems to accomplish the distribution and reheating.
However, it does require labor-intensive inspection and maintenance. There is also a potential risk of the ductwork suffering from unsupervised condensation, mold, and bacteria.
A self-contained humidifier doesn’t rely on ductwork. Instead, it distributes vapor within the space, typically by a packaged unit. These are less common than ducted humidifiers, but they are effective when you only require humidification in a single zone, it’s difficult to retrofit the existing space, or you want to control the humidifier separately from the HVAC system. However, self-contained units can offer floor access for easier operation, inspection, and maintenance. Finally, self-contained models could require several units for adequate distribution, which would affect cost.
Which Humidification Technology Is Best for Your Commercial Air Management?
While there are two main types of humidifiers (isothermal and adiabatic) and two primary types of installation (in-duct and self-contained), many technologies have been developed for use in various applications. By understanding each system’s advantages and disadvantages, you will find the most cost-effective and practical solution for your space. Here’s a quick overview of the most popular humidifier technologies;
Centrifugal Atomizing Humidifier
- Adiabatic
- Atomizing
- Installs in space or distributes via ductwork
- Flush or drain needed in duct
- Relatively inexpensive to install and maintain
- Tends to be noisy
- Maximum capacity is about 20 pounds per hour
Compressed Air Nozzle Humidifier
- Adiabatic
- Atomizing
- Installs in space or distributes via ductwork
- Flush or drain not needed
- Relatively inexpensive to install (unless the compressed air is not already available)
- Inexpensive to maintain
- Electric energy costs for compressed air service can be high
- Tends to be noisy
Direct Injection Humidifier
- Isothermal
- Installs in ductwork or AHU
- Flush or drain not needed
- Steam-powered
- Relatively expensive to install if supply steam is not already available
- Inexpensive to maintain
- Steam-related energy costs can be high
- Always ensure boiler treatment chemicals are safe for steam injection and introduction into supply air
Gas Fired Humidifier
- Isothermal
- Uses gas burner instead of electricity
- Installs in mechanical room and distributed via ductwork
- Flush or drain needed
- Relatively inexpensive to install and run if gas is already in place
Steam to Steam Humidifier
- Isothermal
- Heated by steam from boilers
- Installs in mechanical room and distributed via ductwork
- Flush or drain needed
- Energy efficient
- Relatively inexpensive to install
Electric Resistance Humidifier
- Isothermal
- Installs in space or distributes via ductwork
- Flush or drain needed
- Electric heat source
- Relatively inexpensive to install and maintain, but electric energy costs can be high
Electrode Humidifier
- Isothermal
- Installs in space or distributes via ductwork
- Flush or drain needed
- Electric heat source
- Relatively inexpensive to install and maintain, but electric energy costs can be high
Heated Pan Humidifier
- Isothermal
- Installs in space or distributes via ductwork
- Flush or drain needed
- Steam-powered
- Installation costs can be high, especially if a steady steam supply is not already in place
- Relatively low maintenance, but since it uses steam, energy costs can be substantial
Pressurized Water Humidifier
- Adiabatic
- Atomizing
- Installs in space or in the ductwork
- Flush or drain needed in duct
- High installation costs, but maintenance is generally low
- Runs on electric but is energy efficient and relatively inexpensive to operate
Rigid/Wetted Media Humidifier
- Adiabatic
- Evaporative
- Installs in space or in the ductwork
- Flush or drain needed
- Comparatively inexpensive to install and operate
- Relatively high amount of maintenance requires to manage bacteria and mold which accumulates in the basin
- Low risk of oversaturating the air
- Fairly imprecise control of relative humidity within the space
Ultrasonic Humidifier
- Adiabatic
- Atomizing
- Installs in space or in the ductwork
- Flush or drain needed
- Relatively expensive to install
- Maintenance is generally low, other than replacing disks every 10,000 hours
- Runs on electric but is energy efficient and relatively inexpensive to operate
- Maximum capacity is about 80 pounds per hour
General Considerations When Selecting a Commercial Humidifier
When researching humidifiers for your commercial space, remember that every humidifier type, barring direct steam, requires a water service. This can either be domestic water or demineralized (DM), deionized (DI), or reverse osmosis (RO) water. In addition, some (but not all) humidifiers require treated water.
Water treatment tends to add significantly to installation and operation costs, but it can also improve the humidifier’s overall operational performance. Using the right kind of water can also minimize maintenance intervals and reduce mineral fallout in the space. Note that using softened water can reduce maintenance intervals (by reducing scaling on the humidifier components), but it can increase mineral fallout.
Finding the Right Humidifier Distributor for Your Application
Have questions? Ready to spec your commercial humidifier? Don’t hesitate to contact the experts at Coward Environmental Systems, Inc. We have over seventy-five years of expertise and experience, and we’re always happy to answer any questions.
