Thermal analysis for system uses solar energy as a pressure source for reverse osmosis (RO) water desalination

As Natural resources are becoming limited and energy price dramatically increased, energy utilization with efficient systems is essentially required to be used in desalination technologies. The use of solar energy in desalination processes is one of the most promising applications of renewable energies. The primary focus on desalination by solar energy is suitable for use in remote areas. A proposed desalination system uses solar radiation, which concentrated by parabolic dish to heat up the working fluid in a closed space. Then the generated pressure in this space used to push salt water into RO module.Daily production rate of fresh water quantity for suggested system compared with other solar techniques is a promising rate for each m2 of solar radiation collecting surface. The production rate for one operation cycle could reach to 1800 L/cycle of fresh water at low water salinity (Brackish water with 5000 ppm) and 55 L/cycle at highest water salinity (sea water salinity with 42,000 ppm). The required energy needed to produce 1 kg of fresh water is also promising even when in case of using another type of energy, also operating cycle has ability of repetition according to salinity concentration through sunny hours.

► The system consists of parabolic dish concentrator, Pressure tank and RO module.
► The generated pressure pushes the salt water into RO module.
► Thermal analysis was done to estimate the productivity of the system.
► The analysis shows a promising productivity for each 1 m2/day.
► The productivity may reach 1.8–0.055 m3/m2 day for pressure 5–80 bar.