Improving Ducting To Increase Cooling Performance Of High-end Web Servers Subjected To Signicant Thermal Shadowing -an Experimental And Computational Study

Abstract

Ensuring that all the critical components like CPU's receive sufficient amount of flow as per their requirement is an vital importance in implementing air cooling for IT equipments. In addition to that the overall system resistance varies with the component location with in the chassis. In this study, parametric improvement in chassis ducting system is made to counteract the effects of thermal shadowing in a open compute air cooled server in which a CPU thermally shadows the other. Commercially available computational fluid dynamics codes have permitted simulation of server models to predict efficiency of the servers with every changes made in the design and input variables. Initially this study discusses about the methodology that outlines experimental procedures and tests employed for generating data for calibration of a detailed server model generated using a commercially available CFD tool. The resulting experimentally-calibrated computational fluid dynamics model of the server is used to parametrize improve the duct design and the location with the view of estimating the effect of airflow bypass on fan power consumption and CPU die temperatures. Improvements achieved are experimentally tested by prototyping the improved chassis using acrylic sheets and reported with reduced flow rates, flow speeds, fan power consumption and fan acoustic noise levels. Further, the study is extrapolated for evaluating the savings in total pumping power and flow rates in the layout of a traditional data center and highly-efficient data center working on air side economization. Savings in amount of water consumed by the layout and savings in number of computer room air conditioning(CRAC) units are also evaluated.