新型井下熱交換器之實驗室取熱性能分析

Abstract

這份研究旨在研究一常見之U型管式熱交換器以及我們設計的同心圓多重管式熱交換器應用於地熱能源之取熱效率。藉由減小熱交換器之總體積，測試上述兩種熱交換器的取熱性能。熱交換器使用的管子為四分銅管，高度大約都是20公分，一個是常見於地熱系統的U型管，另一個則是同心圓式的多重管熱交換器。本實驗藉由改變管內流量以及熱源-模擬地熱井側的環境溫度，測量熱交換器進出口的壓力以及溫度來推算各個熱交換器的的總熱阻、壓降、熱傳量以及井側自然對流係數。為了瞭解模擬地熱井內的流動形式，本實驗也紀錄了井內的垂直溫度分佈，同時本實驗也測試了熱交換器內的結垢對於熱傳性能的影響。

The research studies on a common borehole heat exchanger applicable in geothermal energy- the common U-tube heat exchanger and the designed co-axial multi-tube heat exchanger. By reducing the size of the heat exchanger, the heat extraction performance of both heat exchangers are tested. The heat exchangers are composed of 4-charge pure copper tubes, with a height of 20 centimetres, the configurations are a u-tube and a coaxial multi-tube heat exchanger. By means of changing the flow rate and well-side temperature, the overall heat resistance, pressure drop, heat transfer rate, free convection coefficient of well-side are examined by recording the pressure and temperature of heat exchanger inlet and outlet. In order to study the flowing pattern on the shell-side of the heat exchanger, the vertical temperature distribution inside the simulated well is examined. Some fouling effects on heat transfer is also tested in the study.