A simple, low cost set up I have explained in this article will give you a clear idea regarding how to desalinate sea water at a fast rate and in large quantities.
The conventional method of solar sea water desalination process is quite sluggish and cumbersome.
A simple, low cost but effective idea presented here will show you how to desalinate sea water much efficiently.
A Simple Sea Water Desalination Apparatus
A simple and a low cost set up (Exclusively Developed By Me) as shown in the diagram should be able to convert sea water into fresh drinking water in large quantity, depending upon the size of the sphere.
The main feature of this system unlike other conventional ways is the fast conversion rate of waste water into fresh water.
Also, since the whole process is solar operated, cost incurred is zero. Another great advantage of this design is that it's not dependent on the position of the sun and will work throughout the day as effectively.
Let’s study how to desalinate sea water through a simple the set up: The system is basically made up of a large hollow glass sphere with a “T” shaped glass tube extension coming out of its top portion. The sphere is made up of solid glass at the bottom, up to the focal point of the sphere.
This base surface may be painted black to increase the efficiency of the unit. As can be seen in the diagram, the short vertical arm of the tube which extends upwards terminates into a funnel.
The funnel carries a valve in the form of a tap. The long horizontal arm is bent at 90 degrees and terminates inside the reservoir tank.
The whole set up is placed outdoors in an open area where clear sunlight is accessible throughout the day.
Sea water is poured through the funnel and the glass sphere is allowed to fill completely, only up to the circumference of the globe. Now the tap is closed.
How the Desalination System Works?
Once the sphere is filled with water, it behaves like a big, solid and a powerful convex lens. In our childhood days we all have played with this amazing piece of lenses.
We have seen how it is able to focus and concentrate sun rays at one single point when placed at a particular angle under sunlight.
(Click Image to Enlarge) The created focal point is in fact a concentrated beam of the sun rays collected and deflected at a small point.
This point is very hot, and is able to produce burning effect over anything placed under it. The above principle has been simply exploited in the present design.
Without water the sphere is ineffective and will act just like a normal glass. The sunrays entering into it thus cannot generate much of a heat. But the moment it is filled with water, it is transformed into a big solid convex lens having a focal point exactly at its center.
Sun rays hitting the glass sphere are instantly refracted through the entire curvature of the filled water to reach exactly at the center.
Here the rays concentrate into single hot spot. Water at this point starts heating up instantly and the heat is gradually transferred to the whole mass of the filled water.
As the temperature rises, water molecules are converted into vapor. The water vapor formed, rise through the “T” shaped glass tube and the reservoir tank.
The tank being relatively much cooler helps in converting the received water vapor into clean, drinkable water* (see comments) on its roof.
Water molecules accumulated on the roof of the reservoir tank slowly gather to form water drops which ultimately fall into the tank and pure water is thus collected inside the tank.
This water is absolutely pure, and free from viruses, bacteria or dust particles. The efficiency of this apparatus will decrease if the filled water is murky or muddy.
Because in such a case the focal point will be comparatively dull and won’t be able to create enough heat. The above method should have certainly made you understand regarding how to desalinate sea water simply and efficiently.
UPDATE:
Th above design looks quite inefficient since the apparatus is cumbersome and difficult to implement for large scale desalination process. A much better and simpler design can be seen below. The diagram is self explanatory:
