Experimental investigation of the performance of a seawater reverse osmosis desalination system operating under variable feed flowrate pressure and temperature conditions

The integration of Reverse Osmosis (RO) desalination systems with Renewable Energy (RE) technologies offers a sustainable approach to water production. However, the inherent variability of RE sources, along with seasonal shifts in seawater temperature, present significant challenges to the effectiveness of RO membranes. Consequently, there is a critical need for research to examine the impacts of such variations on membrane performance. This study investigates the performance of a small-scale seawater RO (SWRO) unit under variable operational conditions, including non-stable feed flow rate and pressure, across three different feed water temperatures (10, 25, and 35 °C). Utilizing a simulated power produced by photovoltaics on a hypothetical cloudy day for the operation of the SWRO unit, this research aims to address the challenges posed by the variable nature of RE sources and the environmental and economic drawbacks of battery usage. The focus of this research is to assess how these operational variations affect key performance indicators such as water flux, water permeability and salt rejection. The results reveal a decrease in water flux by 0.5×10 -6 m/s and a 12% reduction of the water permeability by the end of the unit’s operation. Furthermore, extremely high values of membrane recovery (up to 40%) were noted, attributed to sudden pressure fluctuations. In addition, sharp pressure variations, especially at low temperatures, result in significantly high specific energy consumption values. These findings underscore the need for careful consideration of operation control strategies in RO units powered by RE to ensure high efficiency and membrane longevity. Implementation of a small-scale seawater RO desalination unit directly powered by PV. Examination of the effects of variable feed flow rate, pressure, and seawater temperature on RO membrane performance. Identification of a decrease in water flux and water permeability coefficient at lower feed water temperatures, attributed to abrupt pressure changes.