The evolution of data center technology has the HVAC industry working toward new normals as trends shift across the market. One of those shifts concentrates on the growth of different data center types. Enterprise data centers — those that are found on the premises of corporations and businesses — grew 13 percent from 2017 to 2018, while cloud data services grew 32 percent in the same period, according to data reports from the Synergy Research Group.

“Enterprise data centers are seeking to become more sustainable and efficient,” said David Klusas, senior director, Custom & Large Systems Offerings, Liebert Thermal Management, Vertiv. “This can be achieved by replacing or upgrading cooling equipment that has been in use for 15 to 20 years. For example, a refrigerant-based system that uses R-22 can be replaced with a new, greener refrigerant system or a chilled-water based system.”

According to Klusas, the growth of edge data centers is exponential as technologies, services, and applications push for a reduction in latency. To accomplish this latency reduction, a small edge data center with supporting infrastructure is often built in a small office or a closet, or is delivered as a modular, self-contained system with racks, cooling, power, and monitoring, not in its own on-premise building like the enterprise data center.

“Space is at a premium in these small locations, and the cooling unit may need to be placed on the ceiling, wall, floor, or on the rack,” he said. “Cooling equipment and configurations must be flexible in these spaces as well as allow heat rejection in a variety of ways, such as piping to the outside or connecting to the building’s cold water loop.”

Klusas also addressed the increasingly popular hyperscale cloud and colocation data centers, noting an increase in size of highly-engineered data centers utilizing custom and standard solutions.

“New data center construction of more than 10 megawatts in size is becoming the norm,” he explained. “We’re also seeing changes in the infrastructure, with multi-story buildings and/or non-raised floor construction. This means that cooling units are changing with the infrastructure — for example, pumped refrigeration economization systems.”



As contractors continue to navigate the data center market, they will find that increasing technology demands are causing several trends that can impact their businesses. First up is the shift in market players.

“There seems to be some emerging partnerships amongst data center infrastructure players within the data center market,” said Michael Zarrilli, executive director, Data Center Solutions, Johnson Controls. “The recently announced Trane and Stulz partnership is an example of that, and we see this as a kind of widening of their product portfolio that certain players are coming to market with.”

Zarrilli noted that a second developing trend is the movement towards liquid cooling.

“This movement really starts with high density servers and pushes itself into liquid cooling, just because it is very effective at high temperature heat exchanger,” he said. “There’s still several technologies that are out there, and I don’t think that a winner has been picked; but there’s definitely a movement towards liquid.”

He explained that there are three different levels of liquid cooling: rack level, chip level, and immersion cooling, where the entire server is immersed into liquid.

A third trend centralizes around rising rack power densities according to Stuart Smith, global sales manager, ServerCool, a division of Nortek Air Solutions.

“Hardware manufacturers are pushing the performance envelope of their equipment at chip level, which in turn is causing challenges when it comes to cooling,” he said. “This isn’t necessarily reserved for high performance computing, as it may have been in previous years. Data centers are also deploying more power-hungry equipment in order to achieve their IT objectives.”

According to Smith, as a result of this trend, there is a drive for manufacturers of cooling equipment to develop products that can cool racks upward of 30kW while maintaining high levels of resiliency, efficiency, and commercial competitiveness.



Design elements and equipment choice impact data center cooling efficiency. It is a symbiotic relationship that HVAC contractors foster as they provide services for data center customers.

An example of this relationship is found in Vycon Inc.’s VDC® Flywheel Energy Storage unit. This product uses flywheels for DC energy storage, paired with 3-phase uninterruptible power systems (UPS). The VDC flywheels and UPSs can operate up to 104°F, compared to batteries that have to run at 77°F.

“The UPS and flywheels can be located either in an electrical room or in a separate space in the data center where they can operate at higher temperatures and save on cooling,” said John Jeter, OEM director, Vycon Inc. “Once you remove temperature-sensitive batteries, you can run the entire data center at elevated temperatures, reducing the overall cooling and power demand.”

Klusas said that cooling data centers is a matter of containment — separating the hot air from the cool air in the most efficient way possible.

“Containing really means you’re only cooling what’s necessary to cool,” he explained. “Instead of cooling a 20,000-square-foot room, you’re cooling 2,000 square feet within the room. In essence, it’s the most efficient means of getting the right amount of cool air to the right place at the right time.”

The Vertiv™ VRC rack cooling system helps accomplish this cooling process. Designed to fit into small racks in server rooms and network closets, this product delivers 3.5 kW of IT cooling. It deploys load-matching, variable-capacity compressors and fans; and comes in multiple heat rejection options. One option is a self-contained configuration, with options for room or ceiling plenum heat rejection discharge. Another option is a split system, using a refrigerant loop and outdoor condenser.

Beyond reduced temperature, data center operators are also looking to achieve high levels of efficiency in the systems supporting their hardware, said Smith.

“This sometimes means maximizing the allowable temperatures within their white space, enabling them to take advantage of newly developed technologies,” he added.

ServerCool’s CDU 1200-1 supports liquid cooled hardware developed by Hewlett Packard Enterprise and Lenovo, among others. It includes the latest water technologies in water purity and controls to ensure a minimal total cost of ownership.

Another design trend being considered is modularity, said Zarrilli.

“Not to be confused with containerization — which defines mobile data centers in shipping containers — modularity can allow data center providers to build out the HVAC system as the data center is itself built out,” he said. “We have products that help enable this and allow data center providers to build in a very effective manner without stranding cooling capacity until the whole data center is built out.”

One of the products that helps with this trend is the YORK® Mission Critical Direct Evaporative Cooling (DEC) Air Handling Unit (AHU). This product has a partial-power usage effectiveness (pPUE) of less than 1.1 and is designed to meet phased data center expansion strategies. It features high media efficiency to reduce water usage.



Predicting the future of anything can be difficult, if not impossible, and the future of data centers is no exception.

“What isn’t difficult to predict is the fact that the number, size, and quantity of data centers built in the coming years will increase dramatically,” said Smith. “Contractors with expertise and experience in this area will be positioned well for growth.”

He expects that artificial intelligence (AI) and machine learning will change the way data centers are cooled, and mentioned that the information and communications technology sector predicts data centers will be responsible for 20 percent of the world’s total power usage by 2025.

“Government organizations are already looking into ways in which they can legislate the power usage in the data center,” Smith explained. “Over the coming years, I expect to see this legislation to come into force, which will cause operators to use the most efficient ways of cooling their equipment.”

Looking ahead, Klusas expects that the bulk of the servers will continue to be air-cooled for the foreseeable future.

“This will result in a continued drive for greater efficiency and lower first cost solutions for the remaining thermal infrastructure,” he said. “Rack densities in select pods or groups of racks within an overall data center will continue to push the need for increased spot cooling solutions.

“Rear door cooling, which has become increasingly popular recently, will continue to be a good solution for these higher density spots,” he added. (See sidebar.)

The final future look at data center cooling comes from Zarrilli, who said that edge data centers will continue to grow rapidly as the applications using them continue to increase.

“Being smaller, these data centers are growing significantly as a result of 5g; as a result of autonomous vehicles which leverage data algorithms; as a result of video streaming; really, almost any low latency applications, where you need the information as fast as possible, are spurring this growth,” he said. “These data centers tend to be a lot smaller, and you’re going to have to have unique cooling solutions for them.”


Data Center Emerging Trends Report

Vertiv™ has released a free report to assist HVAC contractors working within the data center industry. According to the company, this report, “Data Center 2025: Closer to the Edge,” serves as a midpoint check-in on the original report, which was started in 2014. Following are six emerging trends that the company has identified for the coming years.

  • 5G and Edge Computing — “With its high bandwidths and ultra-low latencies, 5G has the potential to accelerate the development of a host of digitally enabled innovations that increase the demand for, and amplify the benefits of edge computing.”
  • Active Rear Door Cooling — “Active rear door cooling has emerged as a high efficiency solution for racks up to 50kW. This approach uses the equipment rack as a containment system with rear-door chilled-water systems removing heat before the air leaves the rack.”
  • Modular Prefabricated Data Centers — “By designing and integrating all components, including the data center shell, in the factory and then shipping the facility in modules that are assembled on site, the traditional stick-build process has been streamlined.”
  • Application-Driven Edge Infrastructure — “These ‘off-the-shelf’ infrastructure solutions will be an important component in enabling enterprises and telecommunications providers to meet the demand for edge services.”
  • Lithium-Ion Batteries — “Increasingly users are turning to industrial lithium-ion batteries that provide longer lifecycles and reduced cooling costs. Based on these advantages and increasingly competitive pricing, lithium-ion batteries could be the primary battery type in the majority of data centers by 2025.”
  • AI and Machine Learning — “Data analytics is not only driving demand for increased computing within data center facilities, it’s also emerging as a new tool for predicting failure and improving performance.”

A more complete outlook on the future of data center equipment can be found in the free, downloadable report available here.

— Source: Vertiv “Data Center 2025: Closer to the Edge”


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