A battery is required in reverse osmosis powered by a photovoltaic system (PV-RO) to prevent inevitable dumping energy and to prolong the operating time of producing water simultaneously. However, the battery is expensive and has a short lifespan. To obtain a competitive water cost, a battery capacity should be as small as possible. This study presents a novel strategy to prevent dumping energy and minimize battery capacity. PV-RO system with battery (PV-RO-Battery) and seasonal water storage tank (SWST) is investigated and its water cost is analyzed. This strategy ensures that all of the daily energy produced by the PV system is used to produce water in less than 24 h, avoiding the accumulation of storing daily excessive energy. Excess daily water production over daily demand is stored in SWST and is supplied to the source of demand when the water production is less than demand. A comparison of a PV-RO-Battery system with and without SWST is also conducted. The reduction of water cost was from 10.21 $/m³ to 2.31 $/m³ and 36.96 $/m³ to 3.06 $/m³ for the constant and variable demand, respectively. It means that the water cost from the system with SWST is only 20.5% and 8.3% of the system without SWST.

在由光伏系统 (PV-RO) 供电的反渗透中需要电池，以防止不可避免的能量倾倒并同时延长生产水的运行时间。但是，电池价格昂贵，使用寿命短。为了获得有竞争力的水成本，电池容量应尽可能小。这项研究提出了一种防止倾倒能量和最小化电池容量的新策略。研究了电池（PV-RO-Battery）和季节性蓄水箱（SWST）的PV-RO系统，并分析了其用水成本。该策略确保光伏系统产生的所有日常能量在不到 24 小时内用于生产水，避免了储存日常多余能量的积累。超过每日需求的每日水产量储存在 SWST 中，并在水产量低于需求时供应给需求源。还对有和没有 SWST 的 PV-RO-Battery 系统进行了比较。水费降低 10.21 $/m对于恒定和可变需求，分别为³至 2.31 $/m ³和 36.96 $/m ³至 3.06 $/m ³。这意味着有 SWST 的系统的用水成本仅为没有 SWST 的系统的 20.5% 和 8.3%。