Liu Zhonghui, Chen Weilun, Zhang Jukui
Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun, China.
School of International Education, Jilin Jianzhu University, Changchun, 130118, China.
Sci Rep. 2024 Oct 9;14(1):23566. doi: 10.1038/s41598-024-75843-x.
Rainwater harvesting systems (RWHs) in buildings are benefits in alleviating urban water scarcity. However, climate change and changes in building water demand affect the expected performance of RWHs over their life cycle. Previous studies have only focused on the adaptability of RWHs to climate change without considering the changes in building water demand. To address this issue, this study explores the impact of combined changes in precipitation patterns and domestic water demand on the water-saving efficiency of RWHs over their 25-year life cycle based on historical observations. Three cities in Japan were selected as case studies. The results indicate that during 25-year life cycle of RWHs, precipitation in different cities in Japan shows an increasing trend, while domestic water demand shows a decreasing trend. Such trend resulted in a change of -2.90-4.02% in the water-saving efficiency of the established RWHs and a change of -2.90-3.82% in the theoretical optimal water-saving efficiency, and these effects were greater in RWHs in buildings with high non-potable water demands. Therefore, RWHs in buildings with low non-potable water demand can appropriately reduce the rainwater tanks, while RWHs in buildings with high non-potable water demand must increase the rainwater tank size to eliminate this adverse effect. Furthermore, both reductions in domestic water demand and increases in precipitation have a positive effect on the water-saving efficiency of RWHs. However, when both domestic water demand and precipitation increase or decrease simultaneously, the change in water-saving efficiency of RWHs is related to the non-potable water demand of the building. This study can provide data support and theoretical evidence for the further implementation of RWHs under climate change, and can help stakeholders to optimize and update RWHs to ensure system feasibility.
建筑物中的雨水收集系统（RWHs）有助于缓解城市缺水问题。然而，气候变化和建筑用水需求的变化会影响雨水收集系统在其生命周期内的预期性能。以往的研究仅关注雨水收集系统对气候变化的适应性，而未考虑建筑用水需求的变化。为解决这一问题，本研究基于历史观测数据，探讨了降水模式和生活用水需求的综合变化对雨水收集系统在其25年生命周期内节水效率的影响。选取了日本的三个城市作为案例研究。结果表明，在雨水收集系统25年的生命周期内，日本不同城市的降水量呈增加趋势，而生活用水需求呈下降趋势。这种趋势导致既有雨水收集系统的节水效率变化了-2.90%-4.02%，理论最优节水效率变化了-2.90%-3.82%，且这些影响在非饮用水需求量高的建筑中的雨水收集系统中更为显著。因此，非饮用水需求量低的建筑中的雨水收集系统可适当减少雨水箱容量，而对于非饮用水需求量高的建筑中的雨水收集系统，则必须增加雨水箱尺寸以消除这种不利影响。此外，生活用水需求的减少和降水量的增加均对雨水收集系统的节水效率有积极影响。然而，当生活用水需求和降水量同时增加或减少时，雨水收集系统节水效率的变化与建筑的非饮用水需求有关。本研究可为气候变化条件下雨水收集系统的进一步实施提供数据支持和理论依据，并有助于利益相关者优化和更新雨水收集系统，以确保系统的可行性。
