Experimental study of a standalone membrane water desalination unit fully powered by solar energy

Abstract

In this study, a fully solar-driven water desalination system is designed, fabricated, and tested. The proposed system is designed for remote, isolated areas with limited electricity and freshwater access. For commercial PVDF membranes, the performance of the MD unit is evaluated at various feed temperatures, flow rates, and salt concentrations. In addition, the effect of MD cell design was examined to determine the effect of the obstacles on the feed channel. Increasing the temperature by 20 degrees from 55 to 75 °C enhances productivity by 165 % from 6.2 to 16.4 kg/m2.h. At different operating conditions, the new design of the MD cell with cylindrical obstacles attained higher flux productivity compared to the conventional MD cell design. The maximum attained freshwater output flux was around 15 kg/m2.h at a feed inlet temperature of 65 °C and feed mass flowrate of 66 kg/h for the MD cell with cylindrical obstacles. In the presence of obstacles, a reduction in the specific energy consumption (SEC) by 35–15 % is associated with an increase in the gain output ratio (GOR) by 50–20 % compared to the case of no obstacles. Observations indicate that a small PV module with an area of 0.377 m2 is sufficient to operate the membrane unit for contentious 15 h. Collectively, using solar MD units collectively has the potential to be used for decentralized desalination of water.