OK, here’s my original idea about how to turn salt water or polluted water into fresh water. You may say, “Perkel, you’re all wet.” But tell me why this wouldn’t work.
As you know – if we run electricity (DC) through water we can separate it into hydrogen and oxygen. We then take the hydrogen and oxygen and run that into a fuel cell which generates electricity and produces fresh water as a byproduct. And the water produced is FRESH WATER, and the electricity generated can be piped back to be used in the separation process.
I’m not proposing a perpetual motion machine. I understand that the power produced by the fuel cell will be less than the power required to split the water in the first place. But this isn’t about producing power, it’s about producing clean water. The recycled electricity just makes it perhaps affordable. Salt water goes in, clean water comes out and the amount of electricity consumed would be maybe 1/5 (80% efficient?) of what it would be if you used electricity to boil the water and then condense the steam.
So – first question – why won’t this work? What am I missing?
Second question – efficiency? If electricity is used to separate water into hydrogen and oxygen and then converted back to electricity in a fuel cell, how much is lost? Anyone have any numbers?
How many gallons of water would you get per kilowatt hour of electricity? Makes you wonder if this were powered by some kind of wave or tidal generator to make the electricity to glean the water – how much water would you get out of this thing?
I can’t follow the formula’s here, but it implies that with some heat capture Marc’s idea might work?
http://www.stardrivedevice.com/electrolysis.html
#18 Paddy-O. You’ve got it. Read my post #7 above. It’s much the same thing but on a much larger scale.
It kills me that the solution can be in place in 5-7 years but isn’t going to happen.
Did anyone mention that Salt Water is a great Conductor of electricity? A lot of your battery power would simply run through the circuit without doing any work. Pure water has a much higher resistance so probably is much easier to split into components.
Just use a vapor compression distiller, powered by solar cells or windmill power. No coal, wood, nuclear power needed.
Another stumbling block is the cost of a fuel cell. They use platinum as a catalyst. This is a rare and expensive metal. There are many much cheaper ways to make fresh water from salt.
Although in many cases it would be even cheaper to be more careful with the fresh water we already have.
#24 “Just use a vapor compression distiller, powered by solar cells or windmill power. No coal, wood, nuclear power needed.”
Workable for low output needs.
Everyone has missed the real answer to “why wouldn’t it work”… COST. How much does it cost to deliver a river of water? Any good solution has to have a low production and maintenance cost
Thermal desalination can be MUCH more energy efficient and MUCH less costly than RO and electrolysis or electrodialysis. Even today’s good thermal technologies use less than 4kW-h/cu.m. plus some amount ( not very large)of WASTE ( low grade)heat.
In any case they are much more efficient(means cheaper) than the proposed one