小型數據中心之熱管理實驗分析

Abstract

本研究主要探討以天花板供風之小型機房內部的安排，改善機房過熱和熱回流情形，機房大小包括半尺寸和全尺寸兩種，以實驗方式針對機櫃擺置、供風量調整和擋板之安排進行探討，其中包括機櫃發熱均勻與不均勻、機櫃距離空調箱之距離和冷通道封閉等等，機房最大發熱量設定為30kW，機房內包含10台機櫃和7個供風口，每台機櫃皆以42個風扇進行強制對流，結果顯示，將發熱量較大之機櫃位於回風口附近，可提高RCI至82 %，且效果優於均勻發熱的配置。機櫃擺置方面，將機櫃和回風口距離增加，RCI可上升至92 %。熱通道空間增加，可使SHI下降至0.32，且機櫃入口平均溫度會隨熱通道空間增加而下降。機櫃上方的回流現象，對入口溫度影響較嚴重，應以擋板封住機櫃之上方空隙，可改善機櫃過熱情形。在擋板之安排方面，將機櫃A以垂直於機櫃之擋板封閉，可有效提高RCI至99 %。當冷通道完全封閉時，機櫃上方會因為冷熱通道壓力差過大，導致機櫃上半部過熱嚴重，其中供風量越小，機櫃入口溫度越低，在供風量為2.83 m3/s時，RCI高達99 %。

This study focused on the arrangement of computer racks inside a small data center with suppling airflow from the ceiling. Various layouts are examined and compared to realize the conditions of inlet overheating and reversed air flow from hot aisle. Moreover, the size of the test data center includes the half-size and full-size, respectively. The experiments are performed subject to the arrangement of racks, various supplied air flow rates, and blockage layout arrangements, including non-uniform and uniform heat generations in racks, distance between racks and CRAH, and containment of the cold aisle layout, etc. The total power of data center is set with 30 kW, and a total of 10 racks and 7 grilles for suppling airflow. Each rack was conducted with 42 fans. For The results indicate that setting the higher power racks near return air can marginally improves the RCI to 82%, and slightly offset the hot air return as compared to that of uniform heating. In the meantime, increasing distance between racks and CRAH could improve RCI to 92%. A slight increase of hot-aisle spacing also improves SHI to 0.32, and the average temperature at entrance of racks will decrease as the spacing of hot-aisle is increased. It is also found that the reversed flow at the top racks has severe impact on the temperature at entrance of racks. To improve the overheating conditions at racks, this study suggests to put a blockage at the top of racks. For the condition of full containment of the cold aisle, the lower pressure at the top of racks incurred by jet airflow bring about severe overheating at the top side of racks. By lowering the supplied airflow rate to eliminate jet air flow, the flow reversal can be significantly reduced and the corresponding RCI at the condition of total supplied airflow rate of 2.83m3 /s may reaches over 99%.