As you are reading this website, some of the bits flowing through the internet to your computer are passing through massive data centers along the way. And you can thank an HVAC technician for it.
Data centers are energy-dense clusters of computing power, centralized to host information storage and processing servers efficiently at the behest of internet supergiants like Amazon, Google, and Yahoo. Scores of less familiar names also operate data centers, subleasing space or server capacity to almost any business that needs a lot of cheap computing power.
Concentrating this equipment in one building makes it easier to shuffle those bits around, not to mention making it more efficient to hire staff to work on them. It also, however, generates a whole lot of heat. A single server can put out almost 1,500 BTUs per hour. According to a 2015 article in Data Center Frontier, a typical Amazon data center hosts between 50,000 and 80,000 servers… servers that would melt down without industrial-strength cooling to keep them running.
With a building boom in data centers and with HVAC systems being so integral to their operation, there is plenty of work for commercial HVAC installers specializing in data center work.
Data center design, and specifically data center HVAC design, is a relatively new science. Data centers consume between 100 and 200 percent the energy of a similarly-sized office space. As the ironclad laws of thermodynamics dictate, all that energy turns into heat at some point and without powerful cooling systems, all those expensive servers would end up as molten slag.
It’s also expensive. Energy consumption is a major expense for data centers, coming in right behind staffing costs according to a 2014 Wired magazine article, representing 30 percent of operating expenses.
Energy efficiency is critical, then, to data center operation. The critical measure of this is called PUE, or Power Usage Effectiveness. It’s a simple formula for HVAC techs to run…
Total Facility Energy Consumption ÷ IT Equipment Energy Consumption = PUE
In the era of the first dot-com boom, data centers were lucky to get a PUE of 2, consuming 2 watts of electricity for every 1 watt of computing power. This was achieved simply by throwing big, fan-driven industrial coolers in place, letting the natural convection of heat rise up into intakes and blasting cool return air up from drop floors beneath the equipment racks.
But, according to Data Center Knowledge, an industry website, by 2014, the average was down to 1.7.
HVAC technicians on both the installation and operation side of the business are a part of that improvement.
Installing Cutting-Edge HVAC Systems Drives Down Data Center Costs…
…But Often Involves Standard Installation Methods
Data centers balance a need to maximize usable space with the need to keep electronics operating at their optimum temperature. Unlike commercial or industrial spaces, data centers require minimal open space for human workers—narrow aisles threaded between industry standard mounting racks are all that are required.
For HVAC installers, this makes airflow more of an exercise in applied ducting than anything else. Data centers typically have drop ceilings and raised floors that serve as integral parts of the airflow management system and further channelize circulation. Hot air rising from the server components is sucked into overhead ducting and run through AC units before being pushed out under the floors to be sucked up by server intakes.
The aisles also play a role in air channels. Racks are set up in pairs, back to back, creating a cool aisle (front, exposed side) and a hot aisle (back to back side). Servers suck air in through their front panels and exhaust it out the rear. This makes airflow setup relatively straightforward. Since air mixing is limited, HVAC return air temperatures do not have to be as low to get ideal server inlet air temperatures.
In some data centers, this is taken even further by explicitly walling off the hot and cold aisles, preventing even incidental mixing from between or above the racks.
Commercial HVAC installers are responsible for putting in both the bones of the ducting systems and the massive compressor and fan units that will circulate the air through them. This means a lot of work with cranes and on rooftops outside. Because data centers are erected in all climates, from desert to tundra, this can mean exposure to all sorts of weather.
On the building interior, the work is like any other construction site—dirty, involving plenty of heavy lifting and brute force. Reading blueprints and mechanical drawings is part of the process.
Placement is Critical for Controlling Costs and Temperatures
Although work is plentiful, it’s also remote. Data centers are built where land is cheap and energy is abundant, which often means in the hinterlands near rivers or remote generating plants. Locating along major rivers also offers a significant source of cooling water and a massive heat sink, such as those built by Amazon and Google along the Columbia River in Oregon.
Increasingly, data center designers are using the environment itself as a cooling source. Consequently, new data centers are more likely to be located at high latitudes where the average temperature is relatively low. In some places, such as at Yahoo’s Lockport, New York data center, outside air is a primary component of the cooling system; elsewhere, it’s simply more efficient to cool the building if the ambient air temperature is starting at lower levels.
Data Center HVAC Operation Balances Cooling and Efficiency With Stability
HVAC technicians who service data centers have to head problems off at the pass. Stability is a primary concern for data center operators. In 2013, according to Data Center Dynamics, a single minute of downtime cost $7,900. Cooling failures are a real risk and technicians have to ensure that they keep systems up and running at all times. There is rarely spare capacity to fail over to when chillers go down.
Electrical outages, on the other hand, is something data centers are equipped for. Massive battery banks or generators are co-located on-site to power both server and cooling systems if outside power goes down. Technicians may be responsible for assisting with or operating these systems and ensuring they are linked up to the cooling units.
Daily operation of the HVAC systems is also carefully monitored and supervised. Although installers will have worked out the basic airflow through the data center, the equipment as it is installed will have an effect on how the center is cooled. HVAC technicians help other staff identify the ideal operating temperature to balance with cooling costs. Any hot spots in the system create inefficiencies.
Technicians will also help advise staff on how to position equipment for the best results. Power-dense equipment, which has higher cooling demands, is located toward the bottom of the racks.
Cable management is something of an art form, but since cables can obstruct exhaust fans, it is important to maximizing efficiency.
Electronics don’t like dust or water, either, so keeping humidity low and eliminating particulate matter is another issue for data center cooling technicians. Complex filtering arrangements require constant attention and maintenance.
Becoming an HVAC Technician In Data Centers
Commercial HVAC work can take technicians into a lot of different sub-specialties, and data center HVAC work is one of them. A solid education and understanding of industrial refrigeration is the best first step to take to an HVAC data center technician job. But like all commercial HVAC work, it’s rarely an entry-level position.
Depending on the locality, you may need to be licensed or certified to work in data center HVAC. Although a trade school or community college program may cover the education aspects of licensing, in most states you need both education and on-the-job experience to qualify.
Apprenticeship programs are a common way to satisfy both requirements. Lasting no longer than five years, an apprenticeship will offer the mandatory classroom education and hands-on training and experience under the supervision of experienced journeyman HVAC mechanics.
There’s another route into becoming a data center HVAC specialist on the service and operations side, which is to simply become a data center engineer. Engineers are responsible for all facets of data center operation, and necessarily find themselves servicing and working with building HVAC systems. In time, specializing in this aspect of the work can lead to dedicated positions servicing data center HVAC units.
Though HVAC technology in data centers is changing quickly, familiarity with ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards is important. A course in data center energy efficiency will help provide that familiarity and may be taken directly through ASHRAE.