NOVELTY - Apparatus (100) for separating caustic soda and fresh water from seawater using sunlight or running water power comprises: positive and negative electrodes (130) respectively provided to opposite sides of water reservoir (110) and watercourse (120) to electrolyze seawater; power supply (140) disposed at one side of watercourse to supply electricity to the electrodes; power generation arrangement (150) to supply power to power supply; and evaporation tower (160) to evaporate caustic soda-containing water to separate caustic soda and fresh water by spraying and heating the water.    USE - As apparatus for separating caustic soda and fresh water from seawater by using green energy such as sunlight or running water power (claimed). The caustic soda is used as a raw material in the manufacture of pulp, textiles, dyes, rubber, and soaps, and as a drying agent.    ADVANTAGE - The apparatus uses green energy to generate electric power from a power generation arrangement such as a solar power generation arrangement or a running water power generation arrangement, and separates seawater containing 3.5% sodium chloride into caustic soda and fresh water using the generated power without the use of an external electric power supply, thus enabling a reduction in costs for production of fresh water and caustic soda from seawater while preventing emission of carbon dioxide and the use of fossil fuels causing environmental pollution and global warming. Further, electrolyzed caustic soda-containing water is heated in the evaporation tower to evaporate moisture and evaporated vapor is delivered to the turbine generator, which in turn uses the vapor for power generation and discharges cooled water to be used as fresh water.    DETAILED DESCRIPTION - An apparatus (100) for separating caustic soda and fresh water from seawater by using green energy such as sunlight or running water power, comprises: a water reservoir (110) pumping, purifying and discharging a predetermined amount of seawater; a watercourse (120) connected to one side of the water reservoir to allow the seawater discharged from the water reservoir to flow through it; positive and negative electrodes (130) respectively provided to opposite sides of the water reservoir and the watercourse to electrolyze the seawater; a power supply (140) disposed at one side of the watercourse to supply electricity to the electrodes; a power generation arrangement (150) generating and supplying electric power to the power supply; and an evaporation tower (160) guiding the caustic soda-containing water electrolyzed through the watercourse into the evaporation tower and evaporating the water to separate caustic soda and fresh water from the water by spraying and heating the water. An INDEPENDENT CLAIM is included for a method of separating caustic soda and fresh water from seawater by using green energy such as solar or running water power, involving: generating and supplying, by a solar power generation arrangement, electric power to a power supply to supply electricity to electrodes; temporarily storing seawater, from which foreign matter has been removed, in a water reservoir, followed by primarily electrolyzing the seawater through the electrodes; secondarily electrolyzing the primarily electrolyzed seawater through the electrodes in a watercourse while allowing the primarily electrolyzed seawater to flow from the water reservoir through the watercourse; generating vapor by raising and ejecting the electrolyzed caustic soda-containing water into an evaporation tower through an ejection port while heating the caustic soda containing water through an evaporation chamber; receiving the heated vapor from the evaporation chamber through a flow duct to operate a vapor turbine generator for power generation; and collecting caustic soda concentrated in the evaporation chamber through a discharge port while liquefying the remaining vapor to use as fresh water after operating the vapor turbine generator.    DESCRIPTION OF DRAWING(S) - The figure shows a view of an apparatus for separating caustic soda and fresh water from seawater by using green energy.    Apparatus for separating caustic soda and fresh water from seawater (100)    Water reservoir (110)    Watercourse (120)    Positive and negative electrodes (130)    Power supply (140)    Running water power generation arrangement (150)    Evaporation tower (160)