Solar: Jean Luc Perrier, solar hydrogen production

[chatelot16]

the chance of gogol make me fall on this document on electrolysis
http://mon.univ-montp2.fr/claroline/bac ... MCH213_002

it specifies things that I already knew but it's good to find everything in a clear document

the simplest electrolyser is with potash and nickel-iron electrodes

the industrial electrolyser operate as hot as possible, and alas must operate above their minimum power, not suited to an intermittent and random power like the photovoltaic sun: good for a solar steam station, which has the same problem of not walking at low power

in this document, they only talk about big heavy industrial solutions: he forgets that we can make a potash electrolyser working cold, so that it can operate at variable power up to zero

it does not explain exactly why the industrial electrolyser can not go down to zero, but we see that at each restart it takes a purge cycle with nitrogen (I suppose to get rid of oxygen that can diffuse or it do not when there is no longer the normal flow)

an electrolyser designed for cold operation must be much larger: impossible for industrial applications where the goal is not energy saving, but this larger dimension per W remains admissible when the goal is ecological

we could think of this electrolysis for an isolated site with photovoltaic and battery: we charge the battery first, then when the batteries are completely full we make the storable hydrogen tablet as long as we want to run a generator

battery and hydrogen are complementary: the battery has a good performance but bad for long term ... the hydrogen has a lower yield but can be stored for a long time without loss

[chatelot16]

What for hydrogen? To date, there is no truly cost effective solution for reuse.

The only "profitable" use of H2 is space

PRODUCTIONS of hydrogen: in 2014. World: 60 million tons ... there is not only space!

of hydrogen production with irregular renewable energy exports will easily find buyer in place of fossil fuel-produced hydrogen

even airliners could use liquid hydrogen

the problem of liquid hydrogen is that it is difficult to preserve for a long time, except for the refrigeration machine that can not be put in an airplane ... but each plane could carry the quantity of liquid hydrogen for take-off and climb at altitude, which is an important much of the consomation of the aircraft and does not pose a problem of storage time since it is safe to consume ... it would be a big benefit because the weight of hydrogen would be lower than the weight of kerosene that it replaces

what made the success of the use of liquid hydrogen and fuel cell in apollo: consomation perfectly planned no loss

liquid hydrogen is completely impossible for vehicles that must be able to stay parked as long as you want without consuming anything

Compressed hydrogen would be possible for vehicles with small tanks not too heavy allowing only a little autonomy: but it would make every day the 10 first km hydrogen produced at home without limiting the autonomy since then we walk with normal fuel

the performance is not as good as an electric car but the weight being lower I find that the result would be good ... a good instalation of compressed hydrogen should also work with methane compressed

[Christophe]

It would be necessary to combine the H2 with something else ... the nitrogen of the air for example to make it more easily storable and thus usable, like H2N2 or H2N4 (hydrazine, highly combustible, also used in the space of elsewhere ...) ...

It should...

[chatelot16]

the right combination with something else is with carbon to make gasoline or diesel

[gildas]

Hello,

There is also the mysterious Ohmasa gas:

It is the gas resulting from electrolysis of water but bubbles do not occur during electrolysis. The HHO gas obtained would be stable to compression and can be stored 2 years in bottles.

https://www.youtube.com/watch?v=NUPE0Z9V82E

See as well:
http://peswiki.com/directory:ohmasa-gas ... no-co-ltd-

[izentrop]

battery and hydrogen are complementary: the battery has a good performance but bad for long term ... the hydrogen has a lower yield but can be stored for a long time without loss

Many generalities that have no place to be. depends

• self-discharge, so the quality of the battery
• materials used and the compression ratio for hydrogen, which is the most volatile gas that exists.

It would be necessary to combine the H2 with something else ... the nitrogen of the air for example to make it more easily storable and thus usable, like H2N2 or H2N4 (hydrazine, highly combustible, also used in the space of elsewhere ...) ...

Very energy-intensive all that.

Cold electrolysis has a low efficiency, the heat engine also, sorry to put that, but the electric everything is by far the most profitable, even with a little self-discharge. It is not for nothing that research puts the package on storage in battery using current materials and nanomaterials

[Christophe]

The "pure" yield matters less if the source is renewable ... since currently only a tiny part of the renewable potential is used!

That the super batteries come out but the path will be long because for the moment the ratio of the mass capacities is still more than 20 in favor of liquid fuels (corrected yields)!

1 kg Lithium = 250 Wh max. at 80% yield = 200 Wh useful / kg ...
1 kg petroleum fuel = 12 500 Wh and 30% yield = 12 500 / 3 = 4200 Wh useful / kg ...

So allow me to doubt on the way "any battery" except technological leap (which oil companies and industrialists will not let happen if it happens ... anyway) ...

In short, liquid fuels (petroleum or synthetic) still have a bright future ahead of them!

[chatelot16]

when we look at the formula of hydrazine it is only hydrogen and nitrogen ... but there is no direct and economical way of associating them ... we need a more complicated and energy-consuming method. than the other ... and the result is a toxic and unstable product, usable only where there is sufficient means, really not the fuel of the future

I do not criticize the battery: it's the most direct way to switch from photovoltaic to another use in the days and weeks that follow ... but the batteries do not allow to store the summer for the winters: Hydrogen-filled steel bottle allows it ... Hydrogen is more easily leaked than other gases, but fortunately we know how to make gas cylinders without leakage.

hydrogen, which is the most volatile gas that exists.

a liquid is volatile when it vaporizes easily to become a gas: how hydrogen which is already a gas can be volatile ???

[izentrop]

Li-O2 batteries "can theoretically reach 3450 watts-hours per kilogram

It's almost coming soon ...

Despite these promising results, the researchers point out that lithium-air technology (also known as lithium-oxygen) will not be developed for at least a decade. Large scale commercialization will only be possible after developing a stable and more efficient battery, with reduced charging times and the ability to charge more than 2000 times.

https://prixdesinnovateurs.arcelormitta ... -lenergie/

So allow me to doubt on the way "any battery" except technological leap (which oil companies and industrialists will not let happen if it happens ... anyway) ...

Countries that have fallen behind, like Arabia is or say, are starting to wake up.
With the price of oil going back to high speed V, good ideas will come back. I think that individual cars and trucking will lose ground in favor of the electric train and the river.

Chatelot16, maintenance charging exists.

[izentrop]

Researchers at CSIRO, RMIT and the Queensland University of Technology have discovered that a simple salt bath, improved the performance of lithium batteries considerably.

Researchers Dr. Adam Best, Dr. Anand Bhatt and PhD candidate Andrew Basile have discovered that treating electrodes in a bath containing ionic liquids and lithium salts reduces degradation of the battery electrolyte during operation.

Basil from ITNEWS says the treatment provided several benefits.

“By allowing metallic lithium to behave safely and efficiently within a battery, we are solving one of the many questions needed to make lithium-superoxide (Li-O2) and lithium-sulfur (Li -S) possible. ”He said.

"These technologies have specific energies of 3,505 watt-hours per kilogram (Li-O2) and 2567 Wh / kg (Li-S) which are much more energy dense than current graphite technologies (typically 100-265 Wh / kg , Li-ion).

"In the real world, that would mean having to charge your battery less often, or being able to deliver more power from a single battery."

Bhatt said a practical lithium-air battery could have the same amount of energy as gasoline, after taking into account efficiency declines in a real device.

http://www.itnews.com.au/news/aussie-sc ... ugh-420706