# Solar Hydrogen Production



## CesumPec (May 20, 2011)

http://www.dangerouslaboratories.org/h2homesystem.pdf

Here's an older idea, from 1994, about using surplus PV to not charge batteries, but crack water into H and O. Any of you tried this?


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## rockhound (Sep 25, 2009)

The cracking is not usually the problem. If you don't use the hydrogen immediately, STORAGE will be the problem. H atoms are the smallest, and will leak out of almost anything not made especially to keep them secured.


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## Jim-mi (May 15, 2002)

Yes storage on a small scale for "Joe Doe" is a major problem........

For an extreem example remember those explosions at Fukushima Japan. . . all caused by H
Now and again I read about H explosions in battery rooms . . . with various degrees of damage.

Wouldn't it be nice if you could go to Home Despot and get a H tank and pump etc....


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## blooba (Feb 9, 2010)

Jim-mi said:


> Yes storage on a small scale for "Joe Doe" is a major problem........
> 
> For an extreem example remember those explosions at Fukushima Japan. . . all caused by H
> Now and again I read about H explosions in battery rooms . . . with various degrees of damage.
> ...


I have no clue what all you would need but http://www.fuelcellstore.com/en/pc/viewCategories.asp?idCategory=108 looks to be a good place to start looking for supplies


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## roachhill (Jul 8, 2009)

I remember a radio show that had on a fellow running his farm off of H he was deriving from windmill power so it's possible but it looks like alot of research and study to figure it out.


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## watcher (Sep 4, 2006)

Its much more efficient to use the extra electricity to charge more batteries. Think about it. You have to make the electricity, convert it to H2 and O2, and (not counting storage) you have to convert H2 and O2 into heat to run an engine. If each step of your process was 80% efficient you wind up with a system which is barely over 50% efficient.


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## CesumPec (May 20, 2011)

watcher said:


> Its much more efficient to use the extra electricity to charge more batteries. Think about it. You have to make the electricity, convert it to H2 and O2, and (not counting storage) you have to convert H2 and O2 into heat to run an engine. If each step of your process was 80% efficient you wind up with a system which is barely over 50% efficient.


I have no expertise in this area to argue otherwise, but batteries are so costly and inefficient, I would want to see proof one way or the other. H and O offer a lot more flexibility than do batteries to power tractors, generators, hot water, BBQ grills, etc. Since I'm going to be grid tied, it isn't really an issue for me. 

My bro ran across the info because his applications can not make much use of batteries because of the mass, both weight and space. He's always looking for things that are easily expandable (inflatable), very light weight, easily transported. But his homestead has challenges we don't worry about such as a very dry environment with extremes of cold and heat each day. I tell him there are better places to live, but he's determined to make a go of it on Mars. And NASA pays his salary so he listens to them more than me.


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## watcher (Sep 4, 2006)

CesumPec said:


> I have no expertise in this area to argue otherwise, but batteries are so costly and inefficient, I would want to see proof one way or the other.


Ugh. . .I thought I had replied to this but it seems to have been eaten by an internet monster. So here goes again.

The numbers our out there to be found with just a little bit of searching. But. . . as they say the proof is in the pudding.

The ability and knowledge to decompose water into H2 and O2 has been around for 150 years. The lead-acid battery tech is almost as old and Li-ion batteries have been around since the 70s. Now take a while and think. How many H2 powered items can you think of? How many are battery powered?




CesumPec said:


> H and O offer a lot more flexibility than do batteries to power tractors, generators, hot water, BBQ grills, etc. Since I'm going to be grid tied, it isn't really an issue for me.


You seem to think H2 is like propane: you make it, tank it and store it until you need it. Well its but it isn't. One of the biggest problems with H2 is the size of its molecules. They are so small they 'leak' through all the common, and most of the uncommon, materials tanks are made of. 

Another is the fact it is energy density stinks. To get a useable amount of energy you have to have a large amount of it. This means you either have to have a huge volume or store it under high pressure. Either way shoots holes all in your efficiency. Huge volume means a large tank which means you have to use a lot of energy to move it. Anyone who knows about it can tell you it takes a lot of energy to compress a gas.




CesumPec said:


> My bro ran across the info because his applications can not make much use of batteries because of the mass, both weight and space. He's always looking for things that are easily expandable (inflatable), very light weight, easily transported. But his homestead has challenges we don't worry about such as a very dry environment with extremes of cold and heat each day. I tell him there are better places to live, but he's determined to make a go of it on Mars. And NASA pays his salary so he listens to them more than me.


When you are using tax money you can afford to do dumb things. In this case it would be better to build and launch prefab nuclear reactors. That way you don't have to worry about the Martian winds blowing the PV cells down or the sand damaging them or what the drastic temp swings would do the them or how to store enough energy to carry you over the sunless hours.


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## CesumPec (May 20, 2011)

Take a 'lude, dude. I'm pretty sure bro isn't looking for ways to crack water on Mars. There's much bigger problems than efficiencies or storage, like the lack of water.


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