There are various ways to convert salt water to fresh water (reverse osmosis is popular). One way is to freeze the salt water. It will form ice that can be melted for fresh water. Normally this isn't the most energy efficient way to go. But it has two advantages, 1) the melting ice may be valuable for air conditioning and 2) ice is a good way to store AC for later use (say if you are using solar energy to run the refrigeration or you want to use power at night when it is cheaper). So it might be practical in places where fresh water, AC and possibly time shifting are needed.

hello, can you tell me any other way to convert sea water to fresh water in houses.


james@Self Storage Units

James;

there are many companies that make small desalination units for residential use

http://www.thomasdesalination.com/text/service.html

yeah i know cmkavala but jonr posted the there are many ways to convert sea water into fresh water that is why i asked what are ways to convert sea water in the houses by myself means without any machine.






james@Self Storage Units

James;

I am not sure that freezing salt water would produce fresh water when melted, the salt does not magically disappear

As you freeze salt water, the salt gets pushed into the non-frozen part (that part gets more and more concentrated). Then you thaw and use just the frozen part. But bubbles and gaps can trap some salt in the ice.

For something proven practical, you need a still or a high pressure reverse osmosis system.

Posted By jonr on 03 Oct 2010 01:05 PM
As you freeze salt water, the salt gets pushed into the non-frozen part (that part gets more and more concentrated). Then you thaw and use just the frozen part. But bubbles and gaps can trap some salt in the ice. 

what you say is true, but Ice floes and other forms of sea ice are less salty than the sea water from which they formed, owing to a process known as brine rejection. Yet sea ice still is too salty to be melted for human consumption.

Old blue sea ice is fresh enough to drink. Salt water frozen in controlled conditions might be. Low levels of salt can also be removed with low pressure RO.

Posted By jonr on 03 Oct 2010 07:19 PM
Old blue sea ice is fresh enough to drink. Salt water frozen in controlled conditions might be. Low levels of salt can also be removed with low pressure RO.

Old blue sea ice is not frozen salt water it is glacier ice which is fresh

I don't agree or disagree, but I find (in numerous places and forms):

Can you drink melted sea ice?
The most basic difference is that sea ice forms from salty ocean water, whereas icebergs, glaciers, and lake ice form from fresh water or snow. When sea ice forms, most of the salt is pushed into the ocean water below the ice, although some salt may become trapped in small pockets between ice crystals.

New {sea} ice is usually very salty because it contains concentrated droplets called brine that are trapped in pockets between the ice crystals, and so it would not make good drinking water. As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all of the brine is gone. Most multiyear ice is fresh enough that someone could drink its melted water. In fact, multiyear ice often supplies the fresh water needed for polar expeditions.

jonr;

so based on your research how does one differentiate old sea ice from new sea ice?

I haven't seen anything to answer that question.

Posted By jonr on 05 Oct 2010 05:48 PM
I haven't seen anything to answer that question.

I didn't either

In reply to jonr. I believe you are extremely misinformed.

Freezing salt water in no way will make it any kind of drinkable. The reason 'OLD' Sea ice is blue, is because first off, it is fresh water. Secondly, what you are calling 'sea ice' formed as a glacier from millions of years of melt water and snow fall both of which are pure water with no salt.

The rule that eskimos use for ice is that if it is blue (its fresh) and you can melt it to drink it. If it is gray or white it contains salt and is not drinkable.

True Sea Ice is always way to salty for you to drink. It forms at colder temperatures than fresh water ice because of the salt content. That salt content does not magically disappear.

In the North Atlantic we use ocean water in our ice makers that we have in our fishing vessels. The ice is colder than normal and keeps the fish at the perfect temperature because of the salt content, if the salt fell away from the ice as it was formed our icemakers would produce fresh ice and leave a large residue of salt in the icemaker. If it weren't for the fact that the salt stays in the ice (even at sea) we wouldn't be able to keep the fish as long as we do.

We didn't always have icemakers, we used to fish ice out of the ocean. There weren't always icemakers, but the ice has always been in the ocean (as long as we can remember). And just like the ice we make, it has a high salt content remains frozen longer and at a lower temperature than regular ice.

You probably want a still for small scale desalination. Look into solar stills as well, they are being used in developing countries to reduce sickness from water borne pathogens, but they work equally well at removing salt.

Refer to wikipedia: "Sea ice is largely formed from seawater that freezes" - not icebergs from glaciers. But no question, new sea ice is much less salty than the sea but still salty.

Does it eventually become fresh enough to safely drink (over several years)? Apparently so - not by magic but because the entrapped brine sinks. Supposedly it gets more blue as this happens.