More than 326.4 million people call America home. Per a Pew Research Center study, more than 75 percent of Americans now carry their own smartphones.

That’s approximately 245 million people.

With each phone hosting a number of personal, professional, and various other social media apps, data use in the U.S. is rampant.

This generation’s rapid deployment of data is birthing data centers throughout the country.

And, as data centers evolve, so do the comfort systems that protect these facilities’ vital infrastructure. One common solution lies in air handlers, which come in many configurations, shapes, and sizes.


While air-handling systems play a large role in keeping data centers cool, it’s important for facility managers and HVACR contractors to understand which type is best for each application.

“Direct evaporative cooling with air-side economizers are the most prolific for data centers 200 kW and above with low- to mid-kW density,” said Carol Baker, senior vice president of marketing, Nortek Air Management. “Direct and indirect designs can provide free cooling. Any climate can benefit from a free cooling unit as can any data center that wants to reduce the cost of operations. Warm climates benefit the most because there is a larger demand for cooling.

“Chilled water design is for high-density load areas where a large cooling duty is required from a compact footprint, and the need to provide reliable and redundant operating is needed for data center cooling,” she continued. “Finally, direct expansion units make up the majority of the data center market. We do not manufacture a CRAC [computer room air conditioning unit], instead, we manufacture a replacement solution to increase cooling capacity, which is a highly efficient chilled water CRAH (DRU) [computer room air handler] and provides immediate energy cost savings from improved efficiency.”

According to Steve Madara, vice president, thermal management data centers, global, Vertiv, choosing the proper air handler depends on many factors, including the customer’s operating set points and how those match up with local climatic conditions for achieving the highest levels of economization.

“Other variables include the building configuration and number of floors, the customer’s preference or lack of preference for the use of water, and the build out plans for modularity,” Madara said. “There is no single solution.”

While there are an array of different types of air handlers, customers often opt to install solutions that are customizable to their setting.

“Custom air handlers are engineered to address challenging requirements for ventilation requirements, size constraints, efficiency, and energy standards of any commercial building not achieved through configured systems,” said Baker. “We make custom solutions, so we can address any capacity — large or small — with various technologies.

“Custom air handlers address concerns for reliability, air quality, and sound,” Baker continued. “In places like data centers, the indoor environment is critical to the business operations. The building in this environment is not just four walls that provide comfort for the occupants. The building is a core part of its operational function. Custom-engineered air handlers provide the flexibility needed in critical and complex environments.”

Similarly, Vertiv is also capitalizing on customized air handlers for data centers, especially in its ability to allow for more precise temperature control and efficiency.

“The precise temperature control and efficiency of custom air-handling units is made possible through the use of highly advanced, intelligent controls,” Madara said. “These types of controls, which are designed exactly for the sophisticated needs of the data center environment, offer data center managers higher energy efficiency, greater protection, and deeper actionable insight at the thermal management systems and unit levels.”


Using air-handling systems to reduce data center energy usage is still a very prevalent trend. With the market continuing to evolve at a rapid pace, new technologies are emerging and will continue to develop over time.

“Air-handling systems will continue to play a large factor in the data center market as a cooling solution for the near future,” said Baker. “However, the data center industry is certainly under the spotlight for its large energy and water consumption. As the market grows, this will drive advanced technologies. For example, new technologies in evaporative, adiabatic, liquid cooling, and more are emerging, and the industry might expect to see new air-handler designs that use this technology to continue to reduce the use of mechanical cooling.”  

Vertiv is also seeing reduced energy usage as a key factor customers are looking for.

“Large air-handling systems designed for data centers continue to evolve in ways that increase energy efficiency and protection through multiple technologies, such as indirect evaporative, direct evaporative, pumped refrigerants economization, and chilled water,” said Madara. “Indirect evaporative systems, in particular, have proven highly efficient, and they keep outside air from entering the data center. Air handlers in data centers are far different than standard commercial rooftop air-handling units. The application of large data center air handlers is an outgrowth of the need for larger scale and capacity units for use in mega data centers by customers pushing the envelope with higher operating temperatures and greater efficiencies. We are seeing a considerable increase in the demand for large air handlers for data centers, especially focused on the cloud and colocation. As mega data centers get larger, there is a need for larger cooling modules and the scale associated with larger air handlers.”


Due to the fact that data centers are continually operating, air handlers are used more, which tends to age them faster and creates more contaminants. UV technology is an emerging trend that more and more data centers are utilizing to keep air-handling units operating at their best.

“Extracting heat from server rooms and data centers requires that HVAC equipment is continually operating at its original design capacity,” said Daniel Jones, president, UV Resources. “However, as air conditioning and refrigeration equipment ages, its ability to maintain temperatures and humidity levels declines. More often, the culprit is reduced coil heat transfer effectiveness, or the ability of air-handling units’ cooling coils to remove heat from the air.

“These inefficient heat transfer rates derive primarily from the buildup of organic contaminants on and through the coil’s fin areas,” Jones continued. “Such buildups are routinely eliminated through the use of light in the UV-C wavelengths. UV-C works by disassociating molecular bonds, which, in turn, disinfects and disintegrates organic buildup and restores cooling capacity and airflow to increase the potential for energy savings. Because cooling systems represent the most expensive parts of a data center facility to both construct and operate, even the smallest improvement in energy efficiency can translate to sizeable savings.”

In the last 10 years, the use of UV-C in air-handling equipment has grown across multiple building types and any building that uses air conditioning can benefit from the application of UV-C with increased performance, decreased energy costs, and improved IAQ.

“Servers generally require an airflow volume of about 160 cfm while blade servers consume about 120 cfm of air between 66° and 77°F per kilowatt,” Jones continued. “Despite these industry benchmarks, most data center operators believe higher temperatures lead to equipment failures. Therefore, half of all data center managers strive toward the temperature goal of 71° to 75°. Given this aggressive set point goal, data center operators believe it is critical to maintain the original design specifications of their HVAC equipment. UV-C offers them a maintenance tool that is working to maintain as-built coil heat transfer efficiency and pressure drop levels on a 24/7 basis,” said Jones.

By eradicating organic matter that has accumulated and grown over time, and preventing it from returning, UV-C technology serves to restore the coil’s performance to regain system capacity. As the system capacity increases, the energy wasted to compensate for lost capacity is returned in the form of lower power consumption, which saves energy.

So, what are manufacturers doing to meet the increasing demands of data centers? Creating and utilizing technology that ensures they meet the needs of data centers of all shapes and sizes while saving energy at the same time.

Publication date: 6/19/2017

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