Browsing by Author "Wang, Cheng-Hao"

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Airflow Management on the Efficiency Index of a Container Data Center Having Overhead Air Supply
(2017-12-01)
Wang, Cheng-Hao
;
Tsui, Yeng-Yung
;
Wang, Chi-Chuan
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機械工程學系
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Department of Mechanical Engineering
Effect of airflow managements on the efficiency index of a small container data center having overhead air supply is reported in this study. Seventeen arrangements and configurations regarding the airflow and blockage arrangements are experimentally examined and compared. Test results indicate an appreciable hot air recirculation occurring for rack arrangement without any blockage, and the hot spot occurs at the second rack alongside the cold aisle. The hot spot had moved to the first rack when the blockage plate is installed on the rack top. Rack locations relative to air handler casts a negligible effect on the efficiency index, and it is comparatively more effective by sealing the trailing of the cold aisle. A smaller cold-aisle spacing helps to lower the temperature distribution, and an additional opening of the supplied vent will not help in removal of hot spot. Shutting off the grille in the center of cold aisle is also unable to fix the hot air recirculation and may even incur hot air reversal. The hot air reversal can be removed by adding additional blockage plate at the flow reversal section. Higher supplied air flow rate also improves the efficiency index considerably.
On cold-aisle containment of a container datacenter
(2017-02-05)
Wang, Cheng-Hao
;
Tsui, Yeng-Yung
;
Wang, Chi-Chuan
;
機械工程學系
;
Department of Mechanical Engineering
In this study, influences of various blockage arrangements as well as cold-aisle containment on the overall efficiency of a container datacenter are reported. The test container datacenter contains ten racks and the cold air is supplied from drop ceiling. The experiments are performed with each rack equally delivering a power of 3 kW. Eight different layouts are examined. Appreciable hot air recirculation prevails especially at the entrance of cold aisle. Adding blockage plates to the computer room air handler (CRAH) at the entrance of computer racks only improve marginally the associated rack cooling index (RCI). Layout with enclosing the end of cold aisle while let open the entrance of cold aisle also performs poorly. Full containment of the cold aisle with high jet air flowrate from the supplied grilles gives the worst performance. Layout with enclosing at the entrance of cold aisle but let open the end of cold aisle shows a much superior temperature distribution and a rather high RCI of 99%. Higher supplied flow may induce jet airflow pattern, causing the Coanda effect to result in fluctuating behaviors of RCI and SHI alongside the cold aisle (zigzag phenomenon). A lower supplied air flowrate without Coanda effect for a full containment design give the best overall performance. (C) 2016 Elsevier Ltd. All rights reserved.