Battery for photovoltaic powered reverse osmosis (RO) system is expensive and has relatively short life, causing high water cost. The problem of battery-less photovoltaic powered RO system is the unstable water production due to fluctuating solar radiation. Therefore, this study introduces the concept of seasonal water storage tank (SWST) in this system to store the water instead of the electricity, resulting in low water cost and stable water supply. Sizing optimization among the main components of this configuration is important to perfectly fulfill the water demand at the lowest water cost. This study developed the algorithms for optimizing the capacities of the components and their capacities combination to obtain the lowest water cost. RO unit capacity was determined based on the designed operating time which was from 4 to 10 h/d. Two scenarios of water demand, constant and variable, were performed for comparison. The results show that the optimum combinations of component capacity were achieved at designed operating time of RO unit at 8 to 9 h/d. The water costs were very competitive which were 1.74 and 2.59 $/m³ for constant and variable water demand, respectively. Therefore, photovoltaic powered RO system with SWST is a promising concept for a stand-alone system.

用于光伏反渗透（RO）系统的电池价格昂贵，并且使用寿命相对较短，导致水费较高。无电池光伏反渗透系统的问题是由于太阳辐射的波动导致水的不稳定产生。因此，本研究引入了该系统中的季节性储水箱（SWST）的概念来存储水而不是电力，从而降低了水成本并稳定了供水。在此配置的主要组件之间进行尺寸优化对于以最低的水成本完美满足水需求非常重要。这项研究开发了用于优化组件容量及其容量组合的算法，以获得最低的水成本。反渗透装置的容量是根据设计的运行时间（4至10 h / d）确定的。为了进行比较，进行了两种需水情况，恒定和可变。结果表明，在RO装置的设计运行时间为8至9 h / d时，实现了组件容量的最佳组合。水成本极具竞争力，分别为1.74和2.59 $ / m^3分别用于恒定和可变需水量。因此，带有SWST的光伏反渗透系统对于独立系统是一个很有前途的概念。