Airflow and Cooling Performance of Data Centers: Two Performance Metrics

This paper focuses on the use of performance metrics for analyzing air-management systems in data centers. Such systems are important for adequately cooling the electronic equipment and controlling the associated energy costs. Computational Fluid Dynamics (CFD) modeling has the capacity to help understand how a cooling solution will perform prior to being built. However modeling also has the capacity to generate an unwieldy amount of data. The crux of the matter is to know what to look for and then objectively characterize and report the performance. Performance metrics provide a great opportunity for the data center industry at large. They could form the foundation for a standardized way of specifying and reporting various cooling solutions. This paper specifically demonstrates the use of two metrics: The Rack Cooling Index (RCI) is a measure of how well the system cools the electronics within the manufacturers' specifications, and the Return Temperature Index (RTI) is a measure of the energy performance of the air-management system. Combined, they provide an opportunity to judge the performance of the air-management system in an objective way subsequent to comprehensive CFD modeling. A real-world example is given for demonstrating the use of these metrics to design a high-density data center The analysis was designed to answer whether a fairly conventional raised-floor system could support significantly higher heat densities than was previously thought. By enclosing the cold equipment aisles, it is demonstrated that the cooling capacity can indeed be greatly increased. This should provide a welcome relief for many data centers that are currently running out of capacity due to a low raised floor.