- 學位論文
數據中心蒸發冷卻之數值模擬
Numerical Simulation of Evaporative Cooling in Data Centers
摘要
隨著科技日新月異的進步，網際網路及資訊軟硬體快速的發展，雲端運算、雲端儲存概念被廣泛應用在各個領域，使得政府機關與企業大量建造或升級原有的數據中心來處理大量的雲端技術服務等，而新一代的IT設備單一機櫃功率可高達10~30千瓦，再加上其他附屬應用產品等，使得機房整體電力與所產生熱能非常可觀。因此如何提升空調效率，或是選用適當冷卻方式將更為重要，如良好的熱管理以及在適當的氣候下使用節能系統，引入外氣來對數據中心進行冷卻。 本研究利用CFD模擬軟體對高架地板型機房及貨櫃型機房進行熱管理的改善與蒸發冷卻模擬分析，理論模式是針對空氣混合物(乾空氣與水蒸氣)與水滴微粒分別採用尤拉法與拉格蘭法進行數值模擬。模擬結果顯示在高架地板型機房機櫃內使用盲板與在冷通道使用檔板阻隔氣流，可防止熱氣回流的問題；而使用節能系統引入外氣並搭配蒸發冷卻方式，可將原本的四台空調減少為兩台運轉。貨櫃型機房之蒸發冷卻模擬分析，使用7 m、20 m及25 m等三種不同直徑的水滴微粒為研究樣品，為避免液滴進入機櫃內，其限制入風口至貨櫃型機房的固定距離內需將液滴需完全蒸發，模擬結果顯示在直徑25 m以上的水滴較不適用在一般標準尺寸的貨櫃型機房，蒸發冷卻後可使外氣溫度降低，作為冷卻設備用途。
並列摘要
With the rapid growth of the Information and Communication Technology (ICT) industry, data centers are essential support for the cloud computing and cloud storage concepts which are widely applied in various fields. Installation of new generation, high power (10~30 kW) IT equipment and other ancillary instruments within a single computer rack, makes the demands to manage both high power consumption and heat generation rates in the data center. Hence, it is essential to improve the efficiency of air conditioning system, the most energy consuming operating system in the data center, or choosing the proper thermal management, or implementing the economizer systems by introducing the outdoor air into data center for air cooling purposes on the suitable weather days. This study aims to investigate the prospective improvement of thermal management and the potential of applying evaporative cooling in the typical data center and container-based data center by using the CFD software. The theoretical model considers the mixing of air mixture (dry air and moist) with fine water droplets in the data center to reach the energy-saving purpose. The computational analysis was based on Eulerian and Lagrangian methods for continuous and discrete phases, individually. For a typical floor-raised data center, the results showed that the use of blind plates inside the rack and partitions in the cold aisles helps prevent the heat reflux and other undesirable issues. With the induction of fine water droplets into the outdoor air in the economizer systems, the droplet evaporation cooling helps reduce the dependence on the use of CRAC air conditioning units, cutting down the demands from four units to two units. As for container-based data center, the fine water droplets with mean size of 7 m, 20 m and 25 m were applied in this study. The water droplets should be evaporated completely within the distance between the air supply side and the container-based data center. The results showed that the water droplet mean size larger than 25 m is not applicable for evaporative cooling purposes in the container-based data center with standard size. The vaporized droplets can reduce the dry bulb temperature within the data center, achieving the energy- saving purpose.