Development of Water and Energy Balance Model with Method to Identify Parameters for Green Roof

近年來能源供應逐漸受到限制，且在極端天氣之影響下，乾旱缺水與短時間之暴雨造成區域排水無法有效疏散而導致淹水的情況日益增加。未來氣候變遷可能惡化此情況，但影響程度評估具有很高不確定性下，集中式的大系統已經很難有效與具調整彈性地處理，因此，需要分散式的小系統來降低能源需求以及乾旱缺水與暴雨淹水等問題。綠屋頂在近年來已成為解決這些問題最有效率的方案之一，屋頂綠化已經在歐洲各國以及美國發展數十年，相對於國外對於綠屋頂之研究，台灣對於綠屋頂模擬分析研究較有限，因此本研究目的是藉由發展物理性模式來模擬綠屋頂之能量與水量平衡，建立推估模式中本土化參數之研究方法，以及設計實驗找出本土化參數與檢定驗證模式的正確性。水文模式利用水平衡方程式進行建構，能量模式則利用地表面能量平衡來進行。實驗觀測結果發現，本研究所設置的綠屋頂，其洪峰時間可延遲至50分鐘；在能量方面，與一般屋頂相比之下，綠屋頂之溫度變化較為平緩。水文模式驗證結果顯示，在時間尺度以小時為單位上之模擬能合理的掌握趨勢，模擬逕流量、滲漏量以及總排水量之效率係數分別為0.69、0.58以及0.61，誤差來源可能在於實驗箱體排水道會滯留逕流與滲漏之水量，以及模式參數之不確定性而造成；能量模式驗證結果為土壤底部效果最佳，可能是因為實驗箱體側向傳導熱導致土壤表面以及其他分層之誤差產生。參數檢定驗證方面，綠屋頂水文參數明顯會因為CN值、U*以及α值而影響綠屋頂洪峰延遲與滯留雨水之效益。本研究發展模式能合理進行綠屋頂模擬分析，未來能將參數取得方法應用在後續其他的相關研究上。包括結合屋內降溫之分析計算，探討綠屋頂節能效果，並進一步搭配雨水儲集系統且將其應用在LID，以利次級供水。Over the years, the restriction of energy supply has increased to a great amount. Under the impact of the extreme weather, water shortage and the flood happened in those areas with insufficient drainage system have become more and more serious. This situation may likely be deteriorated by future climate change. However, since high uncertainty still remains in the impact assessment; centralized systems may not be effective and flexible solutions. Therefore, distributed small systems are needed for reducing the energy demand, water shortage, and floods. Green roof has been on the top of the efficiency list as one of the best solution for energy and water problems. It has being developed and used all over western atmosphere, including the United States and Europe for more than a decade. Compared to those countries, Taiwan’s research to model green roof is very limited. Therefore the purpose of this research is to develop a physical based energy and water balance models with methods to identify parameters for green roof. Besides, an experiment is designed to verify the model. The experiment results showed that our green roof can delay the peak flow to approximately 50 minutes. Besides, the green roof has less of a variance on the temperature. The simulation results show that the value of coefficient of efficiency for runoff, percolation, and total drainage are 0.69, 0.58 and 0.61. The causes of the errors are most likely coming from clogging in the experimental box pipe, and raw data’s instability. The bottom of the green roof has better energy balance simulation, which may have less effects caused by the heat conduction from the experimental box. The verification study indicates the simulation results are significantly influenced by the parameters of curve number, U*, and α. The proposed models in this study can adequately simulate water and energy for green roof. Thus, the models and methods to determine values of parameters can be applied to future researches. It’s suggested to combine the results of this study with the analysis of indoor temperature adjustment to see the performance of green roof on reducing the energy consumption in future. Furthermore, it can also apply to integrate with LID and rain harvesting system