Desalination for Sustainable Water Production with an Emphasis on Low Pressure Distillation

Freshwater resources depletion is a growing concern. This freshwater scarcity motivates research into seawater desalination as a means for alleviating the stresses on water demands. The primary methods of desalination include filtration and distillation. This paper explores the potential energy savings of vacuum distillation for seawater desalination to reduce the amount of energy needed to achieve phase change. Depending on the vacuum boiler design, the vaporization mechanism may be boiling, evaporation, or cavitation. There is very little literature on cavitation that involves mass transfer, so cavitation is not developed here. This thesis focuses on standard models for boiling and evaporation at STP then explores the potential for these models to represent vacuum desalination. To model the transition to vacuum, the model parameters are changed for boiling. The resulting fresh water mass outputs are presented. The purpose is to determine if low pressure conditions are favorable to producing freshwater compared to STP. The final output of this thesis is a proposed algorithm for estimating fresh water mass transfer from a solar vacuum distillation process as a function of heat and electrical inputs