以數值模擬探討日式木造建築室內之自然通風

Natural Ventilation for the Interior of Japanese Wooden Buildings by Numerical Simulation

臺灣之古蹟與歷史建築中，日治時期所興建的木造建築，持續為政府與文化團體所重視，也對這些建築進行修復、活化再利用；但再利用之後，可能因為機能、新機械設備的置入或是安全管理上之考量，對於開口的門窗，長時間可能是封閉的，因而減低了室內環境通風效果，進而影響了構材耐久性。因此本研究在不改變原建築之風貌前提下，利用日式木造建築架高地板之構造特性，藉由適當開口調整，探討室內通風與室內溫度之變化。 研究方法藉由計算流體力學以數值模擬之方法，來探討室內風場的風速、溫度之分佈與變化。模擬結果得知，藉由通風口之增加，室內溫度可降低近攝氏2°C，以及增加了室內流場之對流；此自然通風手法除了可提升室內環境之舒適性，也可減輕空調能源負荷，實現永續建築的理念。

In recent years, the importance of Taiwan’s historic wooden buildings built during the Japanese colonial period are increasingly recognized by the government and cultural organizations. They are repaired and activated for reuse. However, due to the adoption of new equipment and security considerations, the vent openings of these buildings are usually closed; thus reducing the effects of ventilation in the interior and resulting in material deterioration. In recognizing these real situations, this study aims to keep the architectural style and the original historical context unchanged, while the ventilation and temperature conditions inside the buildings are studied while changing the vent openings using computational fluid dynamics. The air speed and temperature distributions indoors are examined. The simulation results show that by opening vents the indoor temperature can be reduced by approximately 2°C and indoor air flow increases. This effect of natural ventilation not only enhances the comfort of the indoor environment, but also reduces the energy load of the air conditioning. Thus the concept of sustainable buildings can be achieved.