Ultrasonic Humidification in the Data Center

The claimed benefits of Ultrasonic Humidification are hard to ignore, but are they worth the cost? Advantages such as claimed 90% energy savings, cleaner humidification and more precise control of relative humidity levels are important to any IT Facilities manager, but do the real world benefits of Ultrasonic Humidification outweigh the costs?

And, yes, there are costs for Ultrasonic Humidification! But many data centers are switching to Ultrasonic Humidification technology.

Stulz manufactures various configurations and sizes of Ultrasonic Humidifiers

The biggest challenges the data center industry faces is simple lack of product knowledge and an understanding of how Ultrasonic Humidification can save them money. In the humidification industry, Ultrasonic Humidification is still a newcomer-even though the technology has been around for decades. A challenge you may face as a facilities manager is lack of selection-there are only two major Ultrasonic Humidification manufacturers with the experience and service the mission critical industry demands: Stulz and Humidifirst.

Humidifirst manufacturers Ultrasonic Humidifiers as well as a Liebert retrofit kit.

Ultrasonic Humidification works on the premise of vibrating water molecules-as opposed to heating them-in order to produce a fine mist (1-2 microns) of discharge. The fact that the water is vibrated instead of boiled means big energy savings. Ultrasonic Humidification uses 90% less energy than isothermal methods of humidification (Infrared and steam canister). Stulz claims up to 93% energy savings with their Ultrasonic Humidifiers.

Ultrasonic Humidification is a method of humidification which uses an adiabatic process rather than an isothermal process to create humidity. In ultrasonic humidification, a small disc (often metal) transducer is vibrated through piezoelectric application of voltage under a thin layer of water. The frequency of vibration is sufficiently high that the water molecules can no longer conform to the waveform induced by the transducer. On the negative portion of the wave cycle, the water cavitates, forming a micro pocket of negative pressure. The water in this micro region is released from the surface tension of the thin film of water. Thus, small water droplets are released into a discharge device, often a tube or fan assembly.

There are few technologies in our industry we can migrate to that can save energy (and dollars) like Ultrasonic Humidification can. There are some important costs that come with Ultrasonic Humidification.

First, the expense of the system. If you design your data center cooling with external humidification, you will be paying for additional units. This is more costly than adding a humidifier component to an air handler that you are already purchasing.

Second, Ultrasonic Humidifiers are expensive. Requests to both Stulz and Humidifirst quoted approximately $800-$3,000 for small, entry level Ultrasonic systems with an output of up to 10 lbs./hr.

Finally, the auxillary systems/components required by Ultrasonic Humidification systems add more costs: Stainless steel or certain plastic lines must be used, as well as DI or Reverse Osmosis water.

The installed price of an Ultrasonic Humidification system can be several times greater than steam humidification systems. If it weren't for that 93% energy savings, the payback period would be extraordinarily long. Both Stulz and Humidifirst claim many customers see payback period of 1-2 years for Ultrasonic Humidificaiton.

Energy savings of 90% or more are hard to ignore. When 20%-30% of a data center's operating costs are allocated to cooling and environmental conditioning, efficiency gains can make a large, positive impact on the bottom line.

In Part II of our Ultrasonic Humidification article, we will go into detail on how the energy savings are achieved. Part II also has a brief demo video of an ultrasonic humidifier in action!