結合CNS照度標準之透天住宅自然採光潛力分析

近幾年的疫情，開啟了居家辦公的可能性，住宅節能較以往更顯重要。自然採光可節省照明用電，若能釐清影響自然採光的因素，將有助於設計出照明節能最大化的住宅。本研究以透天式住宅為研究對象，探討不同平面設計、不同開窗方位以及不同緯度等條件變化下，住宅可利用的自然採光之面積百分比差異，試圖找出在何種條件下，能使住宅產生最大的自然採光效益，節省照明耗能。　　本研究選擇兩個現存於台灣的真實透天住宅案例以DIALux軟體進行日照模擬。兩個案例分別為台灣常見的長型連棟式透天住宅與近期興起的方型社區型透天住宅，透過模擬以比較不同平面設計是否存在著先天自然採光的優劣性。研究結果顯示，有兩向採光及天窗採光的長型透天住宅（案例A），全年採光面積百分比平均為27.63%~38.39%。方形的社區型住宅雖然也是兩向開窗且有露天天井（案例B），但由於需要與周邊住戶區隔，露天天井的一、二樓四周皆有牆壁阻擋自然採光，使其全年採光面積百分比低於案例A，僅約19.12%~26.63%。由此可知平面設計對自然採光有絕對之影響性。　　因兩個案例原始平面開窗方向並非一致，為了排除先天方位不同的影響，本研究將兩個平面旋轉八個方位後，進行方位因素的影響效果比較。雖兩個案例在八個方位自然採光的優劣排序並不相同，但案例A在八個方位全年採光面積百分比差距約10.31%~10.76%，案例B則為7.27%~7.51%，兩個案例年平均最高之方位皆是東西向方位，由此可知開窗方向也會影響住宅的自然採光效益。　　本研究進一步比較台北與台南兩個不同緯度的自然採光差異，結果顯示，全年自然採光面積百分比差距約0.02%~1.33%，平均值僅0.23%，差距微乎其微，幾乎可以忽略。

關鍵字

透天式住宅；自然採光；照度；方位

並列摘要

In recent years, the pandemic has opened up the possibility of working at home, making the residential energy saving more important than before. Daylighting can save lighting electricity. Clarifying the factors that affect daylighting could help designing a residential building with maximize lighting energy saving in lighting. This study takes houses as research objects, and discusses the percentage difference of available daylighting area of houses under different plane design, different window opening orientations and different latitudes. This study aims to find out that which condition can make the house generate the maximum daylighting benefits and save lighting energy. 　　In this study, two real house cases in Taiwan were selected for sunlight simulation using DIALux software. The two cases were long multi-span houses which is common in Taiwan and square community-type houses arisen in recent years respectively. Through simulation, the advantages and disadvantages of innate daylighting in different plane design were compared. The results show that the average annual daylighting area percentage of the long houses (case A) with two-way daylighting and skylight daylighting is 27.63%~38.39%. Although the square community-type houses also have two-way windows and an open-air patio (case B), however, due to the need to be separated from the surrounding residents, there are walls around the first and second floors of the open-air patio to block daylighting, making the percentage of annual daylighting area lower than case A, only about 19.12%~26.63%. This shows that the plane design has an absolute influence on daylighting. 　　Because the original plane windows open-direction of the two cases are not the same, in order to eliminate the influence of different innate directions, this study compared the influence effects of orientation factors after rotating the two planes for eight orientations. Although the rank of advantages and disadvantages of the daylighting in the eight orientations of two cases is not in the same order, the percentage difference of annual daylighting area in the eight orientations of case A is about 10.31%–10.76%, while that in Case B is 7.27–7.51%. In both cases, the orientation with the highest annual average daylighting is east-west, which shows that the direction of window opening will also affect the daylighting benefit of the house. 　　This study further compared the daylighting difference between Taipei and Tainan at two different latitudes. The results show that the percentage difference of daylighting area in the whole year is about 0.02%–1.33%, with an average of only 0.23%. The difference is negligible and can be almost ignored.