CFD analysis of free cooling of modular data centers

Air-side economizers use outside air for cooling information technology (IT) equipment completely or part of the time (coupled with traditional computer room air conditioning (CRAC) units). This system is often used in colder climates and requires less energy since it doesn't use compressors for cooling incoming air. In this paper, thermal performance of an air side economizer for a modular data center is studied using computational fluid dynamics (CFD). The modular data center is comprised of two 12 ft × 40 ft (3.66 m × 12.19 m) IT containers, one 12 ft × 40 ft (3.66 m × 12.19 m) power/cooling module, and a 12 ft × 36 ft (3.66 m × 10.97 m) plenum. Blowers in the power/cooling module draw outside air, pass it through filters, and distribute the air between the two IT modules. The IT modules are arranged in a hot/cold aisle arrangement with a total heat load of 1.2 MW. The two IT modules contain more than 5000 servers, actuator controlled louvers, and sensors needed for cooling system control. CFD analysis of the modular data center showed the importance of louver angles at the inlet of the IT containers. Based on the simulation results improvements have been made to the modular data center by adjusting the angle of the louvers to improve airflow distribution in the servers. This change resulted in significant improvement in the mean exhaust temperature at the servers.