How In-Row Cooling Increases Data Center Efficiency
Cooling efficiency is a top priority for today's data center operators. Increased data
center densities enable operators to deliver more processing power in the same amount of space
to meet the demands of cloud and hyper-scale environments. As more power is consumed per rack,
however, heat becomes a big problem, and traditional computer room air conditioning (CRAC)
units are unable to keep up.
Most modern data centers have adopted some sort of aisle-containment solution to minimize
the mixing of hot and cold air. With cold-aisle containment, racks are positioned in rows with
their fronts facing the aisle, which is enclosed to contain the cold intake air. Hot air from
the rear of the equipment is exhausted into the room, which becomes a large hot-air plenum.
Close up view of the control panel on one of the InRow A/C units, which displays various
status and runtime information. Photo source: Sanity Technology sanitytechnology.com.au
A hot-aisle containment system mirrors this approach - the rears of the racks face the
aisle, which contains the hot air and exhausts it into a drop ceiling void, return system or
computer room air handler (CRAH). Hot-aisle containment is more efficient than cold-aisle containment
because it leverages the fact that hot air rises. It also creates a more comfortable environment
for data center staff and non-racked equipment.
Either way, aisle containment makes it possible to set cooling systems to a higher temperature
while still maintaining a safe operating temperature for the equipment. It also minimizes the
risk of hot spots, and reduces the need for humidification and dehumidification. All of this
reduces costs by reducing power consumption.
However, aisle-containment with a CRAC unit is not as efficient as in-row cooling. As
the name implies, in-row cooling places a cooling unit directly in the row of racks. The unit
may be suspended from the ceiling, placed on top of a cabinet or mounted on the floor. Because
the cooling unit is closer to the equipment, the cold air doesn't have to travel as far and
heat can be dissipated faster. In-row cooling can be used to supplement room cooling, or installed
in a closed-loop arrangement with a cold-aisle containment enclosure.
In-row cooling units may use refrigerant or chilled water, and incorporate fans to distribute
the cold air. State-of-the-art units have built-in intelligence, varying cooling capacity and
fan speeds according to the load.
There are several obvious used cases for in-row cooling. It may be used for a lab environment
within a data center, or to provide more efficient cooling for a customer in a co-location
facility. In-row cooling is also ideal for extremely dense environments, particularly those
that use power-hungry GPU clusters for machine learning and other artificial intelligence applications.
In-row cooling units should be designed to meet customer demand for higher capacity to
address today's heat loads. These units must fit comfortably in any data center environment
for delivering maximum cooling capacity.
Marcus Doran is VP and General Manager at Rahi Systems
Europe. He has over 20 years of experience in data center segment. He has extensive experience
in data center infrastructure solutions contributing well-established relationships with the
customers across the Northern European region.
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