Energy recovery devices (ERD) are vital for improving the energy efficiency of reverse osmosis (RO). Nevertheless, small-scale seawater RO systems are rarely equipped with ERDs, mainly because of the associated high capital and maintenance costs. Herein, we propose a new type of reciprocating switcher (RS)-ERD with dual self-boost hydraulic cylinders that can pre-pressurize the low-pressure hydraulic cylinder during stroke switching. The structure and working process of the pre-pressurization reciprocating switcher (PPRS)-ERD are presented, and mathematical models of the entire system are established. Based on these models, a detailed performance analysis is performed. Compared to the conventional RS-ERD, both the high pressure (HP) check valve cores and hydraulic cylinders move smoothly, which suggests that the vibrations of the check valves and cylinders can be neglected. The maximum pressure fluctuation amplitudes of HP seawater (HPS) at the outlet and HP brine (HPB) at the inlet are 0.015 MPa and 0.016 MPa, which represent decreases of 98.91 % and 98.87 %, respectively. The flow fluctuation amplitudes of HPS and HPB do not exceed 0.17 m³/h and 0.07 m³/h, which represent improvements of 95.34 % and 96.59 %, respectively.

能量回收装置 (ERD) 对于提高反渗透 (RO) 的能源效率至关重要。然而，小型海水反渗透系统很少配备 ERD，主要是因为相关的高资本和维护成本。在此，我们提出了一种新型的往复式切换器（RS)-ERD 带有双自升压液压缸，可在行程切换过程中对低压液压缸进行预加压。介绍了预压往复式切换器（PPRS）-ERD的结构和工作过程，建立了整个系统的数学模型。基于这些模型，进行了详细的性能分析。与传统的 RS-ERD 相比，高压 (HP) 止回阀芯和液压缸运动平稳，这表明止回阀和气缸的振动可以忽略不计。出口高压海水（HPS）和进口高压盐水（HPB）的最大压力波动幅度分别为0.015 MPa和0.016 MPa，分别下降了98.91%和98.87%。HPS和HPB的流量波动幅度不超过0.17 m³ /h 和 0.07 m ³ /h，分别代表 95.34 % 和 96.59 % 的改进。