Method for optimizing equipment cooling effectiveness and HVAC cooling costs in Telecom and Data Centers
ASHRAE Transactions Volume 114. Part1. Presented in the 2008 ASHRAE Winter Meeting
Magnus Herrlin and Kishor Khankari
Raised-floor cooling is the most common way of cooling today’s Data Centers. This paper evaluates two key design parameters for such a cooling protocol; namely, the supply temperature and the supply airflow rate. These parameters not only impact the rack cooling effectiveness but also the energy usage for cooling the space. A leading CFD code is used to accurately establish the temperature field and airflow pattern for different combinations of these parameters in a prototypical Data Center with hot and cold aisles. Based on these comprehensive CFD data, the Rack Cooling Index (RCI) is calculated for evaluating the overall thermal equipment environment. This Index is designed to be a measure of how effectively equipment racks are cooled and maintained within industry thermal guidelines and standards. This paper shows the average RCI for all equipment intakes as well as local values over the intakes of each equipment lineup as computer-generated RCI maps. Based on the results, recommendations are given for selecting supply temperature and supply airflow rate. When the RCI algorithm has been incorporated into the CFD code, engineers and architects will have a new practical tool to evaluate and design Data Centers.