資料中心IT設備之散熱及節能研究

Study of Thermal Performance and Power Saving for IT Equipment in a Data Center

陳錦輝(Chin-Huei Chen)

指導教授 ： 馬小康

國立臺灣大學/工學院/機械工程學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.10523

摘要

近年來，資料中心的成長持續往上提高，其IT設備的耗能亦相當可觀，其中為了散熱需求的電力消耗約佔了整個資料中心的35%~45%，資料中心主要由機架組成且機架中由伺服器佔大部分，本研究以節能為出發點，從伺服器內之散熱元件，伺服器系統，到資料中心機架系統進行分析提供節能之改進研究。
在伺服器內之散熱元件方面, 傳統的伺服器設計多以硬體設備之價格為設計考量，因此對於散熱器多選擇價格較低之材料為出發點來解決散熱問題，本文之研究除了散熱器之價格，使用CFD分析若使用較貴之散熱器而使用較少風量時，節省之風扇電源而省下的電費是否值得使用較貴之散熱器，本研究選擇四種散熱器，先各進行優化，改變鰭片數量及厚度，各找出最佳之設計，之後加以比較散熱性能及耗電。接著改變風扇轉速及風扇尺寸做耗能分析，結果改變風扇轉速獲得較佳之節能效果。原本最便宜的全鋁散熱器已經可以符合CPU之溫度規格, 銅底鋁鰭片之散熱器價格較貴，但可省下28.1%的風扇轉速即可達到和全鋁散熱器一樣的散熱效果，換算成電力可省下16.5W，一年可省下19 USD的電價，已遠超過選用鋁材質散熱器之價差約1.4 USD，本研究可為現在設計設備散熱設計之參考，除了考慮硬體價差，建議可考慮做設計讓步以硬體的錢換取更多省下的電費。
在伺服器系統方面，我們將伺服器系統以分區流場之方法達到節能之目的，各區可各自管理自己之流場以避免分流，可節省風扇耗能約31.0%及減少系統風量使用約12.9%。針對不同負載之伺服器內元件，啟動風扇轉速控制機制後已經可減少風扇轉速及電力31.2%，在使用分區管理流場後，風扇電力可從31.2%再節省至46.2%。若將此分區流場管理應用在資料中心之機房，對於不同負載之機架,在一樣電力下的可提升39%的風量，此分區管理流場之方法從伺服器到資料中心之應用確實有效達到節能之效果。

關鍵字

節能 ； 伺服器冷卻 ； 資料中心散熱 ； IT 設備散熱 ； 區域流場管理 ； 風扇 ； 散熱器

並列摘要

The quantity of data centers has increased continuously in recent years. The power required for a data center to cool its IT (Information Technology) equipment is typically approximately 35%~45% of the data center’s power consumption. Data centers house many racks and a large number of servers. In this study, effective thermal management has been developed for IT equipment from component level to server system level, and also applied to data center level for efficient power saving.
For component level, thermal analysis is used to examine design tradeoffs for heat sinks and fans to reduce power consumption in servers. Heat sinks constructed of aluminum and copper with various fin number and thickness were analyzed. The rotation rate and dimension change of fan are compared for power saving, the result shows that rotation rate change can get the better power saving than dimension change. All-aluminum sinks have the lowest hardware cost for a given thermal specification. The hardware cost for sinks with a copper base and aluminum fins is higher than that of all-aluminum sinks, but the former is more cost effective if we consider electricity consumption, because the fan speed required to achieve the same thermal performance as that of an all-aluminum heat sink is 28.1% lower, representing a 16.5 W reduction in consumption. The annual savings in electricity costs could amount to 19 USD. If we calculate using the 4-year life cycle of hardware, 77.3 USD can be saved, greatly more than offsets the heat sink hardware cost difference of 1.4 USD. This study shall serve as a reference for IT equipment dissipation design. In addition to taking hardware price differences into account, it is recommended that a compromised design be adopted to save more electricity costs and the money be used for hardware instead.
For system level and data center level, the divided zone partition introduces the benefit of one specific zone to avoid airflow bypass and gain power savings. The partition can save 31.0% of the total fan power consumption and reduce the system airflow rate by 12.9%. For a specific load change in the server, the FSC (Fan Speed Control) function can save 31.2% of the fan power consumption. Power savings can be enhanced from 31.2% to 46.2% by implementing the divided zone partition with the FSC function. When the divided zone method is applied in a data center room, it improves the server operating airflow 39% for a specific rack inside a room with different loading racks. The utilization of a divided zone partition shows a significant power savings for IT equipment from the server level to the data center level.

並列關鍵字

Power saving ； server cooling ； data center cooling ； IT equipment cooling ； regional partition ； fan ； heat sink.

參考文獻

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