Numerical analysis of vapor condensation process in a condensation dome of a patent-based solar-vacuum desalination plant

Abstract

Water-desalination process using renewable energy sources have become more and more popular as they can produce drinking water without negative effect to the environment. The present study examines the condensation dome of a vacuum-based water desalination plant using transient 3D finite volume method. The whole system is under semi-vacuum condition (to reduce the boiling temperature of the saltwater) and the water vapor is condensed in the mentioned condensation dome. The objective of the current research is to evaluate the performance of the proposed condensation dome in a patent-based desalination plant under various novel possible geometric and operational conditions which have not been investigated before. First, four different scenarios of the fins are examined for a given time step. Then the best selected fin arrangement is simulated under a wide range of ambient air conditions in the same time step. Finally, the condensation process is simulated for the selected geometric and ambient conditions under various time steps between 1 and 60 s. The results revealed that, adding only external fins, and then considering both internal and external fins can boost the water condensation rate around 24 % and 62 % respectively compared to that for the base dome without any fin. Besides, when both internal and external fins are in the same direction, the condensation performance is 5 % higher than that for case 3 in which any internal fin is located between every pair of external fins. However, condensation rate is less sensitive for fin configuration when ambient air becomes warmer. Furthermore, higher level of ambient air heat transfer coefficient (higher wind speed) boosts the water condensation rate as well. The general outcome for the tested size of the dome is promising with around 2000 gr condensed water after 60s in the best selected conditions.