Faculty of Engineering, Porto University, Portugal.
Department of Civil & Construction Engineering, Swinburne University of Technology, Hawthorn VIC3122, Australia.
Sci Total Environ. 2020 Aug 10;729:138967. doi: 10.1016/j.scitotenv.2020.138967. Epub 2020 Apr 26.
One of the main strategies that are being applied to improve the efficiency of water consumption in buildings is the use of non-potable water for pavement washing, toilet flushing, irrigation, and others. According to several guidelines, the design and assessment of a Rainwater Harvesting System (RWHS) should be made using recent official records of precipitation. However, there is not an indication whether historical or future projections should be used, leaving space for the designer to choose. This article presents the study of RWHS in southern Europe, namely in Portugal, considering two case studies (a dwelling in Oporto and an apartment in Vila Real). The main goal was to explore the impacts that climate change will have on these systems and, for that purpose, a daily simulation using future rainfall data was performed for both cases considering two scenarios: RCP 4.5 which is more optimistic, and RCP 8.5 which is more pessimistic. The RWHS in Oporto showed a better performance in the future decades, comparing with simulations based on recent decades, for both scenarios. However, the savings will not have a significant variation (less than 5 €/year). In the future, this system will provide around 47 (±2.4) m of rainwater per year to the selected non-potable purposes, leading to savings of around 66 (±3.3) €/year. Vila Real case study also revealed a slight improvement of the system's efficiency in the future decades but the results for rainwater collected and used are so similar to the recent ones that it can be concluded that the performance will be sustained. This system will provide around 50 (±2.5) m of rainwater per year to the selected non-potable purposes, leading to savings of around 200 (±10.2) €/year. It can be concluded that there will be no significant changes in RWHS performance in the future, in the studied areas.
提高建筑物用水效率的主要策略之一是将非饮用水用于路面清洗、冲洗厕所、灌溉等。根据几项准则，应使用最近的官方降水记录来设计和评估雨水收集系统 (RWHS)。然而，没有说明应使用历史记录还是未来预测，这为设计者留出了选择的空间。本文介绍了在南欧（即葡萄牙）进行的 RWHS 研究，考虑了两个案例研究（波尔图的一处住宅和维拉雷阿尔的一套公寓）。主要目标是探讨气候变化对这些系统的影响，为此，针对这两种情况，使用未来的降雨数据对两个案例进行了每日模拟：RCP4.5 更为乐观，而 RCP8.5 更为悲观。对于这两种情况，与基于最近几十年的模拟相比，波尔图的 RWHS 在未来几十年的表现更好。然而，节省的费用不会有显著变化（每年不到 5 欧元）。在未来，该系统将每年为选定的非饮用水用途提供约 47（±2.4）立方米的雨水，每年可节省约 66（±3.3）欧元。维拉雷阿尔的案例研究也表明，未来几十年该系统的效率略有提高，但收集和使用的雨水结果与最近的结果非常相似，可以得出结论，该系统的性能将保持稳定。该系统将每年为选定的非饮用水用途提供约 50（±2.5）立方米的雨水，每年可节省约 200（±10.2）欧元。可以得出结论，在研究区域内，未来 RWHS 的性能不会有重大变化。
