由於工作場所的通風問題被長期忽略，空氣中有害物質被作業人員攝入而危害健康頗鉅。由於通風不佳，無法將廠房內的熱量排出建築物外時，也常引致工作環境高溫。近年來因為對工業廠房環境的重視，人們開始改善工業通風問題。本研究使用商用計算流體力學軟體，改變各種設計參數，分析使用煙囪進行自然通風之一般高度廠房或建築廠房的速度場與溫度場，歸納出此類煙囪通風之設計準則。包括：(1)增加廠房的高度，會使入口空氣流量增加，但流速會降低；增加廠房的寬度，會使入口空氣流量線性增加，但流速幾乎不變；增加煙囪高度，可使廠房入口空氣流量與流速都增加；(2)改變煙囪入口面牆高度於適當範圍，可使廠房內氣流平順且無溫度外溢；(3)將單支煙囪擺置後方中間或角落時，廠房側牆與煙囪之間的距離若超過臨界值，煙囪與牆壁之間會形成迴流泡，並使煙囪內的熱氣外溢至室內；(4)多支煙囪擺置後方時，若相鄰煙囪的間距超過臨界值，會使廠房內形成迴流泡，並使煙囪內的熱氣外溢至室內；(5)入口面牆的高度，應設計在合適的範圍內，可使流場迴流泡不致於太大，且流量不致於太小；(6)入口窗戶的開窗率若大於臨界值，可使牆後尾流區較小；(7)在入口面牆裝設百葉窗，若使百葉片角度於適當範圍，可消除入口牆下游的迴流區；(8)廠房內若擺置會發熱的機檯，可依據「稀疏型排列法」與「緊湊型排列法」調整機台間距與排列方式，並將作業人員置於機台側邊走道進行工作，可使作業人員感受到較佳之氣流速度與較低之溫度。以上之設計準則與參數，皆有量化數據，設計人員可獲得具體之參考。

The poor ventilation in the workplace has been existing for decades in Taiwan. The hazardous substances in the air of the workplace are frequently ingested by the workers and induce health problems. Besides, due to the pool ventilation the heat accumulated in the plants and building causes high indoor temperature which reduces the work efficiency. The present study used a commercial computational fluid dynamics (CFD) software to analyze the velocity and temperature fields of the natural ventilation technology using the chimney. Various design parameters were studied for the chimney-ventilated regular-height building with and without installing heat-generating machines indoors. Design guidelines were finally summarized. The design parameters for design considerations included: (1) the effect of building height and width on the induced inlet flow velocity and flow rate, (2) the effect of the chimney height on the induced inlet flow velocity and flow rate, (3) the height of the chimney facial wall on the leakage property of the chimney containment, (4) the appropriate location and number of the chimney, (5) the critical opening ratio of the inlet windows, (6) the appropriate arrangement method of the venetian blind installed at the inlet wall for reduction of recirculation bubble, (7) the arrangement methods should heat-generating machines were installed indoors. The above design guideline and optimized parameters provided designers to achieve high efficiency natural ventilation.

[1] Andersen, K. T., “Theory for natural ventilation by thermal buoyancy in one zone with uniform temperature,” Building and Environment, Vol. 38, No. 11, 2003, pp. 1281-1289.
[2] Gan, G., “Simulation of buoyancy-induced flow in open cavities for natural ventilation,” Energy and Buildings, Vol. 38, No. 5, 2006, pp. 410-420
[3] Schlaich, J., “The solar chimney: electricity from the sun,” Edition Axel Menges, 1995.
[4] Afonso, C., and Oliveira, A., “Solar chimneys: simulation and experiment,” Energy and Buildings, Vol. 32, No. 1, 2000, pp. 71-79
[5] Mathur, J., Mathur, S., and Anupma, “Summer-performance of inclined roof solar chimney for natural ventilation,” Energy and Buildings, Vol. 38, No. 10, 2006, pp. 1156-1163
[6] Kang, J. H., and Lee, S. J., “Improvement of natural ventilation in a large factory building using a louver ventilator,” Building and Environment, Vol. 43, No. 12, 2008, pp. 2132-2141.
[7] Ballestini, G., Carli, M. D., Masiero, N., and Tombola, G., “Possibilities and limitations of natural ventilation in restored industrial archaeology buildings with a double-skin facade in Mediterranean climates,” Building and Environment, Vol. 40, No. 7, 2005, pp. 983-995.
[8] Gratia, E., and Herde, A. D., “Is day natural ventilation still possible in office buildings with a double-skin facade,” Building and Environment, Vol. 39, No. 4, 2004, pp. 399-409.

[9] 黃榮芳，林楷玲，許清閔，「工業通風—原理與實務」，中華環保衛生協會，2020。
[10] Technical Reference：SOLIDWORKS FLOW SIMULATION 2016