Abstract: Aqueous saline solutions are converted in part to potable water by passing a compressed aqueous saline solution through one or more beds of contained pellets of higher temperature to heat the aqueous solution to a flash vaporization temperature, then passing the solution to one or more flash vaporization zones. Vaporized potable water from each vaporization zone is separately passed to contained bed of pellets where water is condensed and pellets heated. Simultaneously, a bed of pelletized solids is heated to supplant the highest temperature bed in the system used for heating. By selective switching of beds, the system is kept in continuous operation with a heated bed of pellets replacing the highest temperature bed previously used to heat the aqueous saline solution. The bed used for water condensation is transferred to the heating cycle for subsequent introduction to the system.