Solar Thermal Assisted Vacuum Freezing Desalination of Seawater at the Triple Point

A spray vacuum freezing desalination process is proposed to meet the required seawater desalination cost, with water subcooling suppression at freezing. The cost of the proposed desalination method is low, with low energy requirement and minimum carbon emission. General statement of how this problem is being addressed: Nucleating agents will be used to suppress subcooling of freezing the sprayed seawater droplets, so that the energy requirement of the vapor compression process can be minimized. The main energy-consuming process, i.e. the vapor-compression, will be satisfied with low-quality thermal energy such as solar thermal energy. What is to be done in Phase I? The Phase I work will focus on demonstrating the feasibility of the proposed concept. One or two proper nucleating agents will be selected, and a bench scale vacuum freezing chamber will be designed, fabricated, and tested. In addition, collaboration with interested partners will be built up. Commercial Applications and Other Benefits: The proposed technology could be applied to seawater desalination and wastewater treatment. Subcooling suppression techniques developed in this Phase I work could also be applied in the application of phase change materials. The low energy requirement and low operation cost are the competitive edges of this technology. Key Words: desalination, freezing, subcooling, nucleating agent, ejector