Data Center Free Cooling Controls Program

David Shroyer, NetApp

This presentation will focus on a case study completed at a NetApp data center in Sunnyvale, California that optimized the use of existing outside air economizers for free-cooling in addition to improving air flow management and the re-setting of supply air temperature to the servers. The energy conservation measures (ECM) that were implemented in the data center consist of the following:

• Installed an array of wireless sensors at the face of the information technology (IT) equipment racks to enable computer room air handling (CRAH) unit supply air temperature (SAT) to be controlled by the temperatures from those sensors.
• Installed physical barriers between hot and cold aisles wherever practical.
• Optimized CRAH unit outside air economizers.

The field evaluation included specific characteristics of the existing data center air cooling systems, characteristics of server loads, and measurements for use of evaluating their operation performance under various operating conditions before and after the installation of hot aisle containment and optimization of the air-side economizer controls. The final case study will include the results for the case study including:

• Technical objectives.
• Technical information on the data center cooling systems and servers.
• Measured parameters.
• Test procedures and sequence.
• Data acquisition and compiling process.
• Performance metrics for outside air economizer cooling and SAT control.

The target estimated savings for the project installed at the NetApp Building 11 data center was 14 percent from electrical energy associated with cooling the IT equipment. The technical objectives of the test were to demonstrate the effectiveness of using an array of wireless sensors at the face of the IT equipment racks to enable CRAH unit supply air temperature to be controlled at the inlet to the racks; improved air flow management by installing physical barriers between the hot and cold aisles; and optimizing the CRAH units' outside air economizers.

The following parameters were monitored or measured during the evaluation:

• Main electrical power to data center.
• Actual power demand for IT equipment.
• Actual power demand for the CRAH cooling systems.
• Central chilled water plant power.
• CRAH supply and return air temperatures.
• CRAH economizer position.
• Outside air temperature and relative humidity.
• Chilled water supply and chilled water return water temperatures.
• Selected IT equipment racks inlet air temperatures.

Biography:

David Shroyer, has more than 25 years in the HVACR industry, with the last 15 years in designing and engineering automation controls for high-tech companies, commercial, and real estate investment trusts. His work includes data center design and implementation of EEM projects, and was recently involved with the Green Grid, EPA legislation for Data Center Energy Efficiencies (HR6), Energy Efficiency Measures (EEM), Silicon Valley Leadership Group-Energy Watch Partnership Programs, and Energy Management Programs. He is a member of Association for Facilities Engineering, ISA, and RSES.

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