Abstract: The sub-ambient solar desalination system includes a solar pond and a pressure reducing structure. The solar pond is adapted for receiving saltwater and heating the saltwater through direct exposure to solar radiation at atmospheric pressure. The pressure reducing structure is in fluid communication with the solar pond for receiving heated saltwater therefrom. The pressure reducing structure is configured such that pressure of the heated saltwater within a central portion of the pressure reducing structure is at sufficiently reduced sub-ambient pressure to undergo a phase change to produce pure water vapor and a concentrated brine solution. The pressure reducing structure has a vapor outlet for releasing the pure water vapor, which is collected in a fresh water tank and condensed into pure liquid water. The solar pond is in fluid communication with an outlet portion of the pressure reducing structure for recycling the concentrated brine solution back to the solar pond.

Abstract: A low energy desalination system with a venturi device includes a saline water feed, a pump, and a venturi device. The pump provides saline water to the nozzle of the venturi device. The fluid flowing through the nozzle speeds up at the throat or constricted region of the device. This results in a reduction in pressure at the throat of the device. The reduced pressure at the throat of the device makes the fluid susceptible to evaporation which causes a certain amount of water to evaporate from the saline water. Freshwater vapor from the fluid flows through a freshwater vapor outlet at the throat of the venturi device to a freshwater tank and the concentrated brine remaining in the venturi device flows toward the diffuser of the venturi device and then to a brine tank.