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Two hour electric flights anyone?

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Mark Agate18/02/2016 09:05:20
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If these guys are right, we'll all be using these soon...

**LINK**

J D 818/02/2016 09:51:50
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I would like to know how the fuel pellets are produced and the costs involved, both moneytary and environmentally.

The electric car is very clean at its point of use but producing the battery pack and the electric to charge it is where the cost is.

Its the same for the hydrogen car, producing and storing the fuel has all ways been the problem.

Could this be the answer then?

Piers Bowlan18/02/2016 10:25:23
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Three times the energy density of Lithium batteries! The solid state hydrogen fuel is stable at 500 degrees, water vapour is the waste product. here. impressive stuff.

Wingman18/02/2016 10:56:46
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Astounding! Had me checking it isn't April 1st!

Steve Houghton 118/02/2016 11:10:32
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Using hydrogen as a fuel is not a new idea. For those of us of a certain age group, (which is probably the majority on this web site wink 2), who remember that old BBC news program Nationwide, (which was shown each evening after the 6 o'clock news), there was a story about a guy who, I think was from the Manchester area, had devised equipment to run his car off hydrogen. This is going back to the early 1970's I think.

This equipment he fitted in the car boot along with a tank of water. Petrol was used to start the car, then the hydrogen plant used the hydrogen stored within the water to power the car.

Not surprisingly, nothing ever came of it and I seem to remember hearing rumours that the inventor was bought out by a petrolium company.

J D 818/02/2016 12:42:08
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Yes hydrogen fuel cells have been around a long time. William Robert Grove of Swansea came up with the idea in the 1830's The problem has all ways been producing and storing the hydrogen in a cost effective way.

Apollo 13 had big problems with its fuel cell,all though that was in the liquid oxygen section but it does illustrate the dangers of storing liquid hydrogen/oxygen that this new solid method may overcome.

David perry 118/02/2016 12:46:13
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But water vapour is a big environmental issue in contrails.

And if you thought glow fuel was volatile !

D
Martin Whybrow18/02/2016 12:48:54
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The problem with water as a source of hydrogen is that it takes exactly the same amount of energy to separate the hydrogen and oxygen as you get from burning the hydrogen; add in the fact that thermodynamics limit the efficiency of any energy conversion process and it's obvious that water as a fuel doesn't work.

It is possible to get the hydrogen out of water chemically, e.g. react lithium metal with the water, but then you'll need a lot of lithium and will need to get rid of a lot of lithium hydroxide (which, incidentally, contains half of the original hydrogen that was in the water, so you only get half the amount of hydrogen gas as you would be electrolysis).

The pellets sound very interesting as a storage medium though.

Simon Chaddock18/02/2016 13:27:55
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The electric 'fuel' cell has been around for quite some time indeed such was used to provide electrical power the Apollo lunar missions in the 19 60s but can give trouble as Apollo 13 found out! wink 2

Hydrogen is not really a wonder "fuel" as it is so reactive it is not plentiful on earth in its natural state. It has to be 'extracted' which takes as much energy to do as it releases when it is converted back to water. It is simply acting as a medium to store energy.

Mark Agate18/02/2016 13:36:16
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I think people are confusing fuel and batteries here. Lithium batteries do not generate energy, they just store it. It has to be generated elsewhere.

If hydrogen pellets can store energy safely at this kind of density, they'll be an ideal way of powering vehicles of the future, and our models, providing they can be made economically.

Andy.I18/02/2016 13:50:42
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Posted by john davies 8 on 18/02/2016 09:51:50:

[snip]

The electric car is very clean at its point of use but producing the battery pack and the electric to charge it is where the cost is.

[snip]

Clean at the point of use but they produce seven times more pollution that an IC powered car, just somewhere else - where the electricity is generated!

Andy Meade18/02/2016 14:19:09
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Assuming of course that safe, clean, nuclear power isn't used wink

Edited By Andy Meade on 18/02/2016 14:19:21

Don Fry18/02/2016 15:18:44
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Posted by Andy.I on 18/02/2016 13:50:42:
Posted by john davies 8 on 18/02/2016 09:51:50:

[snip]

The electric car is very clean at its point of use but producing the battery pack and the electric to charge it is where the cost is.

[snip]

Clean at the point of use but they produce seven times more pollution that an IC powered car, just somewhere else - where the electricity is generated!

Source of assertion please, as I don't think, though I may be wrong, that power stations are less efficient power converters or greater polluters than an individual car engine, or are you also factoring in energy and pollution consequences of battery production.

Frank Skilbeck18/02/2016 17:29:36
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Posted by Andy.I on 18/02/2016 13:50:42:
Posted by john davies 8 on 18/02/2016 09:51:50:

[snip]

The electric car is very clean at its point of use but producing the battery pack and the electric to charge it is where the cost is.

[snip]

Clean at the point of use but they produce seven times more pollution that an IC powered car, just somewhere else - where the electricity is generated!

Love to see where you get that reference, a gas fired power station with exhaust heat recovery is 55-60% efficient a diesel engine running at optimum load is less than 50%. Have you also thought of pollution caused by producing and refining oil.......................

Peter Christy18/02/2016 18:54:37
1243 forum posts

The article is less than clear about whether the pellets are *producing* hydrogen or simply *storing* it. Back in the 80's, I think it was, BBC's Horizon programme did a study of hydrogen power. Hydrogen is tricky stuff to store. Liquifying it requires a massive refrigeration unit, and storing it under pressure is plain dangerous. It will leak past almost any valve, and they demonstrated the pressure issue by knocking the neck off a cast iron hydrogen bottle (a bit like an oxy-acetylene bottle). The metal cylinder shot across the desert like a torpedo, spewing out highly flammable hydrogen behind it! Not what you wanted in a car or 'plane!!!

But then they showed it being stored at low pressure in a similar cylinder containing a substance that could absorb vast quantities of hydrogen, releasing it only when gently warmed. I note the article linked to above mentions warming the pellets, so I'm guessing this is similar to what the American researchers were doing on the Horizon programme 30 years ago!

Knocking the neck off the bottle this time only produced a slight "phut" sound, as there was virtually no pressure in the container.

Be that as it may, if they've found a way to store the hydrogen cheaply and safely, it could indeed be a breakthrough.

As for producing hydrogen, all you need is water and electricity - which brings us back to nuclear power! The thing is that you can't easily throttle a nuclear power plant back at times of low-demand - mostly over-night, hence cheap rate electricity. So if overnight, the surplus was used to produce hydrogen from water, then it would solve two problems in one hit!

Of course, you would still have to produce the infrastructure to support a hydrogen economy, but we did it with petrol and diesel, so why not?

Oh, and in that Horizon program, they were running internal combustion engines quite happily on hydrogen, without the need for expensive fuel cells........

--

Pete

Martin Whybrow18/02/2016 20:03:16
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The pellets store the hydrogen, I believe it's effectively 'pressurised' to 5 bar (although it's actually absorbed into the pellet material rather than being under pressure).

The storage medium for hydrogen you saw on TW was metal hydrides; they're expensive and difficult to produce and require the use of metals such as sodium or lithium, but were previously the only way to store hydrogen in a readily retrievable form, other than in a gas cylinder.

Not sure if you've seen it, but a new electric vehicle designed in the UK and running on hydrogen was announced yesterday.

Martin Whybrow18/02/2016 20:04:01
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Posted by Mark Agate on 18/02/2016 13:36:16:

I think people are confusing fuel and batteries here. Lithium batteries do not generate energy, they just store it. It has to be generated elsewhere.

I didn't read it that way.

Peter Christy19/02/2016 09:51:12
1243 forum posts

Martin: Yes, hydrides does ring a bell. Presumably the people in the article have found a cheaper alternative. And yes, I saw the article about the Welsh electric car. Wouldn't be much use for carrying my models around, though....!

--

Pete

Simon Chaddock19/02/2016 11:21:59
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And technically you don't need "hydrogen" to achieve a 2 hour powered electric flight.

It is quite possible (and even longer!) with an ordinary LiPo. wink 2

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