伺服器內散熱器及風扇之節能分析

An Analysis on Energy Saving for Radiators and Fans Inside Servers

最近雲端產品的需求不斷提升，而支持雲端科技的資料中心亦持續成長，資料中心的耗能相當可觀，現在單一Rack 之設計即可達20 KW，而Rack 又以伺服器為主要組成之設備，傳統的伺服器設計多以硬體設備之價格為設計考量，其中CPU 為主要發熱源，通常為伺服器內價格最高之散熱器，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，本研究選擇兩款材料銅及鋁，先各進行優化，改變鰭片數量，各找出最佳之設計，之後兩者加以比較散熱性能及耗電，銅散熱器價格較貴，但只需71.7% 的風扇轉速即可達到和鋁散熱器一樣的散熱效果，可省下16.6 W 的電源，若用台灣對工業用電的電價計算，一年可省下28 USD，以一般四年淘汰一次硬體設備計算，可省下112USD，已遠超過選用鋁材質散熱器之價差，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。

Due to the rising demand for cloud products in recent years, datacenters in support of cloud technology have also continued to grow. Datacenters consume considerable energy, reaching up to 20 KW for the singleRack design. The server is the main component of the Rack. The traditionalserver design in the past took hardware equipment price as the maindesign consideration. In particular, the CPU was the main heat source,and usually the most costly radiator in the server. Hence, more affordable materials were usually chosen as radiators in order to solve the heat dissipationissue. In this paper, in addition to radiator prices, CFD analysiswas conducted to determine if using the most costly radiator with less airoutput would lead to more energy saved and fewer electricity fees in orderto make the use of the most costly radiator worthwhile. In this study, twomaterials, namely, copper and aluminum, were selected for optimizationand the number of fins was changed in order to find the best design. Thetwo were then compared for dissipation performance and energy consumption.The copper radiator was more costly, but it only needed 71.7%of the fan spinning speed to achieve the same dissipation result as thealuminum dissipater, saving 16.6 W of power. Calculated using Taiwan’sindustrial electricity costs, 28 USD can be saved every year; calculatedusing the 4-year cycle of hardware, 112 USD can be saved, greatly exceedingthe price difference of using aluminum radiators. This study shallserve as a reference for IT equipment dissipation design. In addition totaking hardware price differences into account, it is recommended that acompromised design be adopted to save more electricity costs and themoney be used for hardware instead.