KlingStubbins Uses FloVENT Airflow Simulation to Improve Server Rack Efficiency

KlingStubbins improved the efficiency of their server rack cabinets – and the energy efficiency of the data centers that house them – by using FloVENT to simulate airflow around the rack.

“I selected FloVENT because it is widely used, well-validated, fast, and dependable.”

Quantifying server rack performance

KlingStubbins needed to improve energy efficiency of an existing server rack product that is installed in existing data centers. The integral rack fans add an electrical load on the facility Uninterrupted Power Supply systems and impose a thermal burden, as well.

Thus the main goal of the study was to quantify the benefit provided by the fans and determine whether or not modifications can be made to the cabinet to allow the fans to be disconnected, as well as allow for cooling airflow in the computer room to be tailored to the specific load for air-handler fan energy savings.

FloVENT is chosen to simulate airflow

Physical testing would not have been a viable approach, since it was obvious that a large number of design alternatives would have to be investigated to achieve acceptable server inlet temperatures without rack fans.

KlingStubbins addressed these issues by simulating airflow in and around the rack with FloVENT Computational Fluid Dynamics (CFD) software.

“I selected FloVENT because it is widely used, well-validated, fast, and dependable,” said Michael Schwarz, Mechanical Engineer and Associate at KlingStubbins. “It is also important to note that Mentor Graphics' support engineers have extensive experience in CFD modeling techniques and thermodynamics.”

11 design scenarios are evaluated

The simulation evaluated 11 different design scenarios (download the PDF of this success story for details about each design scenario). The simulation results demonstrated that placing blanking panels at various locations within the cabinet, covering the front cabinet door, and rearranging the plastic inserts in the rear door made it possible to disconnect the fans while reducing all server inlet temperatures below existing values.

“Overall,” Schwarz says, “the design improvements developed through the simulation make it possible to turn off both the fan trays and specific CRAC fans for substantial energy savings while maintaining server inlet temperatures below the previous design. The key is improving airflow management in the data center.”

The potential energy savings is significant, since the racks are used in large numbers in some of KlingStubbins’ client’s data centers

“It would have been very expensive and time-consuming to investigate these design alternatives by building prototypes and evaluating their performance in a live data center.”