Page 1 - How sealing gaps under IT racks can lead to significant savings

February 3, 2016By Lars Strong

How sealing gaps under IT racks can lead to significant savings

In previous articles we’ve discussed the importance of sealing
gaps both within IT racks as well as gaps between IT racks in
order to optimize your data center’s cooling and ultimately
reduce operating costs. What we haven’t talked about are the
gaps commonly found under IT racks, which due to their
inconspicuous location, are often left unsealed. If not
addressed, these gaps can potentially be extremely harmful
to IT equipment, leading to costly capital expenditures down
the road.

The Need for a Solution

Often overlooked, the small space between the bottom of an IT rack or cabinet and the raised floor or
slab can have a significant impact on IT inlet temperatures. This space allows for exhaust air
recirculation, as air from the hot aisle flows under the racks into the cold aisle where IT equipment at
the bottom of racks pulls in the hot air. This leads to hotspots, which can ultimately lead to degradation
of IT equipment. Since we recently enhanced our AisleLok® Under Rack Panel, we conducted a
computational fluid dynamics (CFD) analysis using Future Facilities’ 6 Sigma software to examine the
effectiveness of sealing these gaps.

The CFD analysis revealed the impact of sealing these small gaps, which reduced temperatures as a
result of eliminating the exhaust air recirculation under the rack. Furthermore, sealing the gap under
the rack created opportunities to improve overall airflow management efficiency and increase cooling
capacity by raising temperature set points and reducing fan speeds.

The Results

This image shows the variation in IT equipment intake air temperatures across a row in the CFD model.
The dark gray areas are where blanking panels fill locations without IT equipment. The maximum IT
inlet temperature is 86.4° F.

BEFORE (Unsealed openings underneath IT cabinets)