工研院綠能所提出並設計一種新型單相沉浸式伺服器冷卻系統，採用熱虹吸式熱管熱交換器並以風扇取代循環泵來帶動工作流體循環。藉由挑選工作流體以及採用較順暢流場的方式來提升系統的熱傳能力，並降低散熱能耗來達到節能的目標。實驗將電子元件浸泡於冷卻油中，以顯熱作為熱交換的機制。本研究架設性能測試平台，以模擬機架式伺服器的運作狀態，內含可調式電熱器以模擬發熱晶片，並由沉浸式工作流體將熱移至熱管熱交換器的蒸發部，接著藉由熱管熱交換器的雙相熱傳的特性，將熱能從蒸發部帶往冷凝部，並使用風扇將熱排至環境中。
本實驗改變加熱源的功率及冷凝側風扇的風速，針對兩種黏度的工作流體，在系統達穩態時紀錄並觀察系統的工作行為及性能。實驗結果顯示，當機架式伺服器模擬熱量為5000 W時，採用低黏度(5 cSt)工作流體並之下，熱源最高溫度低於78 ℃，此時系統的PUE效率(Power Usage Effectiveness)1.083，比文獻數據更節能且具更高的散熱能力。

The Industrial Technology Research Institute proposes a new novel single-phase immersion cooling system, which adopts a thermosyphon heat pipe heat exchanger (HPHX) to dissipate heat to the environment. Superb energy-saving features are obtained by selecting a suitable working oil and designing an even and smooth flow pattern. Either of two oils with different viscosities is selected as the working fluid. The oil is driven by a set of axial fans in place of liquid pumps. The heater power and fan frequency are varied to test the steady-state thermal characteristics and performance of the system. A test stand is constructed to simulate racked servers cooled by single-phase immersion cooling. The heat from the dummy heaters transmits to the evaporator of the HPHX through the oil by heat convection, to the condenser through phase change of the working fluid within the HPHX, and then to the environment by a cooling fan. The results show that, when the low-viscosity oil (5 cSt) is used, the maximum temperature of the chips is lower than 78 ℃ at a heating power of 5000 W, with a Power Usage Effectiveness (PUE) of 1.083. The present system outperforms the single-phase immersion cooling systems in the literature.

摘要 i
Abstract ii
致謝 iii
目錄 iii
表目錄 vi
圖目錄 viii
第一章 緒論 1
1.1 研究背景 1
1.2 資料中心散熱型式 2
1.2.1 氣冷式散熱 2
1.2.2 液冷式冷卻 3
1.3 沉浸式冷卻文獻回顧 3
1.3.1 兩相沉浸式冷卻技術 4
1.3.2 單相沉浸式冷卻技術 5
1.3.3 熱管熱交換器 7
1.4 可行性評估 8
1.5 研究目的 11
第二章 實驗設備與方法 12
2.1 實驗方法及目的 12
2.2 實驗設備與架構 12
2.2.1 實驗設備 14
2.2.2 實驗步驟 21
2.3 實驗流程 23
2.3 實驗參數 27
第三章 實驗結果及討論 30
3.1 不同黏度之冷卻液對設備的散熱影響 30
3.2 不同風速與功率下熱穩態溫度點測量 33
3.2.1 溫度點數值 33
3.2.2 冷凝區移熱量 42
3.2.3 系統熱阻與加熱功率及冷凝風扇頻率之關係 43
3.2.4 散熱系統能源使用效率 44
3.3 浸沒油槽流場變化 46
3.4 與現有文獻比較 50
第四章 結論 52
參考文獻 54

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