雙相封閉式熱虹吸環路(TPCLT)是一個高效率的雙相移熱工具，其系統包含蒸發部、冷凝部、蒸氣頭、蒸氣線、液體頭以及液體線，移熱的方式主要是利用工作液體的相變化將熱能由蒸發部移至冷凝部，此裝置為自然且單向循環並不需要而外的動力裝置，並具有將熱量長距離傳輸的能力，所以十分有利於應用在太陽能熱水與建築物一體化。
　　本篇論文主要是研究TPCLT環路系統在太陽能熱水器的應用，實驗中有小型與大型兩種環路，實驗參數在小型TPCLT環路為不同結構以及加入不同長度毛細物質對於熱轉換效率的影響；而大型TPCLT環路則為不同填充量測試、加熱功率啟動測試。小型TPCLT環路實驗結果顯示加熱瓦數為360瓦時，非對稱型環路的效率為70.8 %，而Top-U-Symmetric 和 Both-U-Symmetric的轉換效率分別為74.6%和76.1%，而當多孔性毛細結構放入蒸發管內時，Top-U-Symmetric的轉換效率增加為81%。大型TPCLT環路實驗結果顯示此系統填充量為70%且在加熱功率為630W時，熱轉換效率為69%；填充量為60%且在加熱功率為630W時，熱轉換效率為63%。而在系統填充量為70%時，最低可啟動的加熱功率為270W，填充量為60%時，最低可啟動的加熱功率則為180W。

A two-phase closed loop thermosyphon (TPCLT) is a high-efficiency two-phase heat transfer device, which is composed of evaporator, condenser, vapor head, vapor line, liquid head and liquid line. The basic concept is the phase change of a working fluid is used to transport heat from evaporator to condenser through natural circulation without any external driving forces. The device is capable to transport heat for a long distance, so it is proper to apply on the building integrated solar thermal systems.
This study presents the possibility of the TPCLT apply on the solar thermal storage system. This experiment contains two different types of TPCLT, the small one and the large one. In small TPCLT, experimental results show that when heating power is 360W, the non-symmetric TPCLT’s efficiency is 70.88%, the top-U-symmetric TPCLT’s efficiency is 74.6% and the both-U-symmetric TPCLT’s efficiency is 76.1%. When the porous material is put in the top-U-symmetric TPCLT, the efficiency increases to 81%. In large TPCLT, experimental results show that the storage efficiency is 69% in filling ratio 70% with heating power 630W. The storage efficiency is 63% in filling ratio 60% with heating power 630W. When the system is in filling ratio 70%, the lowest start-up heating power is 270W. When the system is in filling ratio 60%, the lowest start-up heating power is 180W.

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