Parametric investigation of a raised-floor data center cooling using a reversible fan system

The active tile cooling has become one advanced thermal management approach for offering an appropriate amount of cooling air to raised-floor data centers. However, difficulty remains to alleviate the waste of the CRAC-supplied cooling air when the data center is over-cooled. In view of this concern, this paper especially investigated a reversible fan system, including a ductwork assembly and a fan unit. This configuration was capable of delivering cooling air upwards into the above-floor space as well as working oppositely to draw unnecessary cooling air backwards into the under-floor plenum to be a smart solution. In this way, the fan unit was able to control the airflow of the perforated tile more flexibly than the conventional fan unit of the active tile systems. The computational fluid dynamics (CFD) model was established to analyze the performance of a raised-floor data center cooling using the reversible fan system, and the key operating conditions (e.g., the rotational speed, rotational direction and the vertical position of the reversible fan unit) were defined and the airflow/thermal performances (e.g., local rack inlet temperature, and the air flow distribution in the cold aisle) were observed and compared carefully. Eventually, the results indicate that the reversible fan system is capable of managing the airflow and thermal distributions efficiently and economically.