目前電腦機房空調循環系統分為冰水循環系統、冷媒直膨式循環系統以及冷媒液泵式循環系統。冰水循環系統利用冰水作為工作流體，但必須承擔冰水洩漏的風險。冷媒直膨式系統須將壓縮機置於冷卻元件之機櫃之中，會佔去一部分的空間使擺設冷卻盤管的位置縮小，因此製冷能力較低，且冷媒的工作壓力較高。冷媒液泵式循環系統的冷卻元件中不需使用壓縮機，在相同機櫃大小中可保有較大的空間放置較大的冷卻盤管，且將冰水移出機房可避免冰水洩漏的風險。
在本論文中第一部分開發一套冷媒液泵循環系統，工作流體採用冷媒R134a，冷卻能力為30kW，管外為空氣，利用熱交換器設計理論設計冷卻盤管(蒸發器)，蒸發器採用板鰭管式熱交換器，尺寸為長250 mm、寬54.6mm、高1722mm，熱傳面積28.56 m2，採用246根管子，一排82根總共三排管路。並利用熱力學理論對冷媒液泵循環系統進行熱力學分析，計算其性能係數COP (Coefficient of Performance)為5.77，並完成循環相關元件尺寸設計，最後利用所設計的元件完成冷媒液泵系統原型機的架設。
第二部分針對水平式電腦機房空調系統，利用計算流體力學軟體進行分析，機房中冷卻元件將冷空氣吹出的空間稱為冷通道(Cold Aisle)，伺服器排出熱風的空間稱為熱通道(Hot Aisle)。本研究考慮單一熱通道機房模組大小為長：10000 mm、寬：4820 mm、高：3440 mm，機房內放置兩排(2 rows)機櫃與冷卻元件，一排中有9台冷卻元件(冷卻能力30kW/冷卻元件)和10台裝載伺服器的機櫃(發熱功率27kW/ servers)。而熱通道位於在機房中央，冷通道則在機房兩側。扣除機櫃長度(910 mm/ cabinet)後，固定冷、熱通道間距總和為3000 mm下，改變熱通道間距(800 mm~2600 mm)，探討10種不同冷、熱通道間隔組合對於機房冷卻能力的影響，並利用機櫃冷卻指標(Rack Cooling Index, RCI)進行冷卻效果的評估。結果顯示，在熱通道間距小於1800 mm時，熱通道間距越大RCI值越大；當熱通道距離大於1800 mm時，熱通道間距越大，RCI值越小；當熱通道間距為1800 mm、冷通道間距為600 mm時，RCI值為100%，此為最佳排列方式。

The method of data center cooling is divided into (1) chilled water cooling system (2) direct expansion refrigerant cycle system (3) pumped refrigerant cycle system. Chilled water cooling system is using chilled water as the working fluid, but it has the risk of leakage chilled water. In direct expansion refrigerant cycle system, compressor shall be placed into standard cabinet will take up part of the space so that the placement of the cooling coil shrink, thus cooling capacity is low, and the refrigerant pressure is high. Pumped refrigerant cycle system without using compressors can retain a large space to place a larger cooling coil in the same cabinet size and can prevent water leakage risk.
The first part of this thesis is developing a pumped refrigerant cycle system, the working fluid using R134a in the tube side. According to the theory of heat exchanger design cooling coil that cooling capacity of 30kW (evaporator), using the plate-fin and tube heat exchanger that the length, width, height and heat transfer area of the heat exchanger is 250 mm, 54.6mm, 1722mm, 28.56 m2. Using thermodynamic theory analysis system to calculate the coefficient of performance (COP) is 5.77, and the completion of the relevant component size design. Finally, we set up the prototype of the pumped refrigerant cycle system.
The second part of the thesis is that data centers in-row cooling system analysis by computational fluid dynamics (CFD). In data centers, the space of cooling unit blowing cold air is called cold aisle and the space of server exhaust hot air called hot aisle. This study considers a single aisle module size of length, width, height is 10000 mm, 4820 mm, 3440 mm, and the room placed two rows cabinet and cooling units, a row of nine cooling units (cooling capacity 30kW / cooling unit) and 10 servers (power 27kW/ servers). Hot aisle is located in the central room, and the cold aisle is located in the room on both sides. Fixed the sum of cold and hot aisle size is 3000 mm, changing the hot aisle size range from 800mm to 2600mm to investigate the effect of cooling capacity with ten different combination of hot and cold aisle size and then using Rack Cooling Index (RCI) assess the cooling effect.
The results indicates that when the size of hot aisle is less than 1800 mm, the greater hot aisle size, the greater the value of RCI. When the size of hot aisle is larger than 1800 mm, the greater hot aisle size, the smaller the value of RCI. When the hot aisle size is 1800 mm and cold aisle size is 600 mm, the value of RCI is 100% that the best aisle size combinations.

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