創新誘導式冷卻水塔之實驗研究

An Experimental Study on an Innovative Induction Flow Cooling Tower

鄭鴻鈞(Hong-Jun Zheng)

指導教授 ： 蔡尤溪

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00566

摘要

多台冷卻水塔並排運轉時，因吸氣距離不足，出風端濕熱空氣回流造成短循環，使得冷卻水塔性能降低，亦導致空調冰水主機效率下降，耗電量上升，為解決冷卻水塔結露產生之白霧現象，有人提出使用電熱、太陽能集熱器及熱管等用來防止冷卻水塔白霧的產生，但以上方法都需購置設備及耗電成本。
本研究利用全尺寸之冷卻水塔實驗，改變冷卻水塔風筒高度及擴散型風筒角度，並在風機下方風筒作環狀開口，以風扇吸入口之負壓對冷卻水塔外部氣流產生誘導現象來改善冷卻水塔濕空氣回流與白霧問題，發現誘導口以不影響冷卻水塔能力且能發揮改善濕熱空氣回流與防止白霧的效益下，誘導口較適化開孔率為9.5%冷卻水塔出口面積，並與原冷卻水塔比較其差異性，當安裝擴散風筒時其風量增加7.5%回流率減少22.1%能力增加4.6%，安裝擴散風筒與增加誘導口其回流率減少67.7%能力增加6.6%，經由煙流可視化實驗將各狀態點標示於空氣線圖上，可知誘導風口與原出口狀態混合後其出口狀態濕度比明顯下降，並使得出入口混合曲線偏離飽和線，由此驗證創新誘導式冷卻水塔可減少濕空氣回流率與明顯地減少白霧產生之效果，使用創新誘導式冷卻水塔可對節約能源有很大的貢獻。

關鍵字

冷卻水塔能力、濕空氣回流、誘導口開孔率、防止白霧

並列摘要

When cooling towers are set up in rows, insufficient separation can result in insufficient inflow distance between the towers. The short circuit flow of wet air can cause lower performance of cooling tower. In consequence, the chiller performance will be affected and also chiller power consumption will increase. Moreover, mist at the outlet of cooling towers during the cooler seasons often require some way of reheat at the tower outlet. However these methods of mist prevention are often costly.
Therefore this study made use of a full cooling tower experiment to test the effects of using velocity recovery (VR) stack and an innovative flow induction design. Openings at around the fan inlet were used to induce wet air directly to the fan inlet. This flow induction was to reduce the wet air return and to prevent excess mist formation. It was found that opening ration of 9.5% had good effects compared to the original design. The use of VR stack was found to increase the flow by 7.5%, reduce the wet air return by 22.1%, and also increase the capacity by 4.6%. The combination of VR stack and induction opening can reduce the wet air return by 67.7% and increase the capacity by 6.6%. Flow visualization showed that when compared to plots on psychrometric chart, humidity at the tower outlet decreased after mixing with the induction flow. The deviation from saturation point has the effects of mist prevention, and proved the effectiveness of this innovative design.

並列關鍵字

cooling tower capacity ； wet air return ； induction opening ； mist prevention

參考文獻

[17] 張永宗，「冰水主機最佳排序」，冷凍與空調雜誌，2002年10月，第87-92頁。

[1] Jameel-Ur-Rehman Khan,M. Zubair,“A comprehensive design and performance evaluation study of counter flow wet cooling towers”.,Energy Conversion & Menagement,44,pp.2073-2091,2002.

[7] Jaber.H.andWebb R.L.,”Design of Cooling Towers by the Effectiveness-NTU Method.”,ASME J.Heat Transfer.,111.No.4.,pp.837-843,1989.

[9] Michael J. Bitondo, Mark J. Tozzi, "CHILLER PLANT CONTROL", Carrier Corporation Syracuse, New York, 1999.

[10] S.W. Wang, S.K. Tyagi, Report on the prediction, potential and control of plume from cooling towers of International Commerce Center, The Hong Kong Polytechnic University, Hong Kong,2006.