既有建物「綠建築化」適宜性評估之案例研究

A Case study on Suitability Appraisal of Turning Buildings Green

洪巧軒(Chiao-Hsuan Hung)

指導教授 ： 周慧瑜

朝陽科技大學/理工學院/營建工程系/碩士(2010年)

摘要

因應全球暖化與氣候極端化，以及科學家所提出地球溫度上升攝氏兩度後即進入不可逆生態毀滅循環的嚴重警告，世界各國對於節能減碳議題應展現出積極態度與實際作為。尤其對營建業而言，依據調查，台灣的建築產業耗能所排放的二氧化碳量占全國排放量之28.8%，顯示營建業對於排碳所造成之環境衝擊，有更責無旁貸的責任。
過去國內較顯著可見的相關政策，主要是綠建築的推動。不過就綠建築標章的評估內容看來，現行制度所關注的焦點，在設計出使用階段上具有節能減碳效果的房子，但若從建築物生命週期的角度來看，新建、整建、拆除重建或者內外部設備建材的更換，都會在營建、運輸、生產及廢棄物處理等過程中產生碳排放等環境成本，若對於既有建物也同樣單從使用上強調「綠建築化」的好處，則是否會因忽略上述其他連帶製造的環境成本，導致更多碳排放的發生。對於營建業而言，節能減碳的課題不僅止於建築物使用階段，台灣建築業占全國28.8%的排碳量中，有9.31%、1.49%分別來自建材生產與營建運輸。因此非使用階段之排碳量亦不可忽視。
為探討上述疑慮是否在現實中可能發生，本研究以一通過綠建築標章之建築工程新建案為例，以其原規劃設計作為「綠建築化」後之建物條件並當作基準組，再依據該案在計算綠建築指標時，對於非綠建築情況之建物條件設定，建構一假設該棟建物去除所有綠建築設計後之情境條件作為對照案例組，而後計算當該建築由一棟非綠建築，經部份拆除整建而綠建築化時，依照建築指標的觀點所獲得使用階段的節能減碳效益(即減少的排碳量)，以及在拆除整建過程中所產生的排碳量；兩者再從成本效益比較的觀點進行敏感度分析，以瞭解既有建物的綠建築化就總體排碳量而言，是否可能發生對當下減緩氣候暖化威脅的急迫任務沒有幫助，反而可能帶來更多環境負擔的問題。
經案例分析結果得知，在拆除與建築施工階段的環境成本，確實可能大到不足以抵銷建材、設備或結構在使用階段所獲得的節能減碳效益。此結果正呼應了本研究擬強調的觀點，亦即在追求既有建物「綠建築化」時，應以更全面的角度進行環境成本與效益的評估，以避免造成更多的環境傷害。

關鍵字

綠建築 ； 環境成本 ； 建築物生命週期 ； 節能減碳

並列摘要

In order to respond to global warming and extreme climates, as well as the serious warning proposed by scientists saying that the Earth will enter an irreversible cycle of biological destruction after the global temperature rises by 2℃, every country in the world should show active attitudes and actual deeds aimed the issue of energy saving and carbon reduction. Especially for the construction industry, according to surveys, the CO2 emission quantity from energy consumption in the architecture industry in Taiwan has accounted for 28.8% of nationwide emission quantity, which shows that the construction industry has its unshirkable responsibility for the environmental impact caused by carbon emission.
In the past, the more obvious related policies in our country are mainly the ones regarding the promotion of green buildings. However, in terms of the assessment content of Green Building Label, the focus concerned by the existing system is to design a house encompassing the effect of energy saving and carbon reduction at the using stage. However, if judged from the angle of a building’s life cycle, the undertakings, such as new construction, renovation, dismantling and reconstruction, or replacement of internal/external equipment and building materials, will all produce environmental cost such as carbon emission during the processes of construction, transport, production, and discard disposal. For the existing buildings, if the advantages of “green building construction” are simply emphasized in the aspect of usage, the question is whether much more carbon emission will occur due to the ignorance of the aforementioned other environmental costs produced accordingly. For the construction industry, the issue of energy saving and carbon reduction is not only limited to the using stage of a building. In the 28.8% of nationwide carbon emission quantity that the construction industry in Taiwan has accounted for, 9.31% and 1.49% of it respectively derive from building material production and construction transport. Therefore, the carbon emission quantity at the non-using stage should not be ignored.
In order to explore whether the aforementioned doubts will possibly occur in the reality, a new project of construction work that has passed the Green Building Label was taken as the example in this study. Its original planning and design were applied to be the building condition after “green building construction”, which was used for the baseline group. Then, according to such a project’s building condition setting for the situation of non green buildings when the green building indicator was calculated, the situational conditions were established, assuming that all the green building designs have been removed from such a building, which was used for the control case group. Later, the calculation was performed, aimed at the effectiveness of energy saving and carbon emission (namely the reduced carbon emission) at the using stage acquired according to the perspective of architecture indictors, as well as the carbon emission quantity produced in the process of dismantling and reconstruction, when such a building was undergoing green building construction through partial dismantling and reconstruction from its original status of a non green building. Then, based on the perspective of cost-effectiveness comparison, the Sensitivity Analysis of the two was performed, in or order to understand the problem whether the green building construction of the existing buildings may not do any help to the current emergent task for slowing down the threat of climate warming but result in many more problems of environmental burdens instead, in terms of total carbon emission quantity.
Through Case Analysis, the findings indicated: The environmental cost at the stage of dismantling and building construction may be too great to counteract the effectiveness of energy saving and carbon reduction obtained at the using stage of building materials, equipment or structures. Such results have exactly echoed with the perspective the study intended to emphasize. That is to say, when pursuing the “green building construction” of the existing buildings, we should undertake the assessments of environmental cost and effectiveness based on a more comprehensive angle, for fear of resulting in much more environmental damage.

並列關鍵字

environmental cost ； green building ； energy saving and carbon reduction ； a building’s life cycle

參考文獻

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