Abstract：
Higher water ages are linked with water quality decline as chlorine dissipates, temperatures become more favorable for microbial growth, and metals and organic matter leach from the pipes. Water fixtures with automated purging devices can limit water age in premise plumbing systems, but also increase water use. To develop purging strategies that lower age while also minimizing water use, the stochastic nature of water demands must be considered. In this research, a hydraulic plumbing network model, with stochastic demands at fixtures, was used to compare water age and water use for five purging conditions: purging at regular intervals, \"smart\" purging (considering the time of last use), purging with different volumes of water, purging at different fixtures, and the purging with different levels of home occupancy. Higher purging frequency and volume resulted in lower water ages, but higher water use. Purging greatly reduced the variability in water ages, avoiding extreme ages entirely. Water age was minimized by scheduling the purging around occupancy behavior, such as before the occupants wake up or return from work. Scheduled purging used more water than smart purging. Purging after 12 h of nonuse used only 55% of the additional water required for purging every 12 h. Purging after 24 h of nonuse at the kitchen tap and shower used only 38% of the additional water required for purging every 24 h, while maintaining lower water ages and removing the variability in water ages. While larger purging volumes had a greater impact on water age, there were diminishing returns. Purging has a larger impact on low-occupancy homes because fixtures have less frequent use. Overall, this research provides a methodology to compare purging strategies that minimize both water age and water use. While the numerical results presented here are only valid for the specific layout and usage habits, they provide insights and trends applicable to other cases.
摘要：
随着氯的消散，较高的水龄与水质下降有关，温度变得更有利于微生物生长，金属和有机物从管道中浸出。带有自动吹扫装置的水装置可以限制房屋管道系统中的水龄，同时也增加了用水量。为了制定降低年龄的清除策略，同时最大限度地减少用水，必须考虑用水需求的随机性。在这项研究中,液压管道网络模型，随着固定装置的随机需求，用于比较五种吹扫条件下的水龄和用水量：定期吹扫，“智能”清除（考虑上次使用的时间），用不同体积的水吹扫，在不同的固定装置处吹扫,以及不同家庭占用水平的清洗。较高的吹扫频率和体积导致较低的水年龄，但更高的用水量。吹扫大大减少了水年龄的变化，完全避免极端年龄。通过安排围绕占用行为的吹扫，将水龄最小化，例如在居住者醒来或下班返回之前。计划清除比智能清除使用更多的水。在厨房水龙头和淋浴间不使用24小时后,吹扫只使用了每24小时吹扫所需额外水的38%。同时保持较低的水年龄和消除水年龄的变化。虽然较大的吹扫体积对水龄影响较大，收益递减。清除对低占用房屋的影响更大，因为固定装置的使用频率较低。总的来说,这项研究提供了一种方法来比较吹扫策略，最大限度地减少水的年龄和用水量。虽然这里给出的数值结果仅对特定的布局和使用习惯有效，它们提供了适用于其他案例的见解和趋势。
