Re: Hydrogen for cars
- From: Dirk Bruere at NeoPax <dirk.bruere@xxxxxxxxx>
- Date: Fri, 27 Jun 2008 15:43:00 +0100
Ian Macmillan wrote:
"Uncle Ben" <ben@xxxxxxxxxxx> wrote in message
news:ddb82064-f1ed-404b-88e8-af3b092f22f7@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jun 25, 11:43 am, Dirk Bruere at NeoPax <dirk.bru...@xxxxxxxxx>
wrote:
Ian Macmillan wrote:couldThe main value of hydrogen is at its endpoint of use in a fuel cell. The
considerable difficulties of manufacture, storage, transport and safety
probably rule out its practical use in bulk, except as a political
boondoggle.
However, there are a variety of methods using chemical reactions that
bulkproduce hydrogen from water at the point of use, so that the need forthirtyhydrogen is eliminated. A recent example uses aluminium amalgamated with
gallium, but similar schemes, some using iron, have been around for
andyears.
To produce hydrogen from water using electricity is very inefficient,
independentuses far more energy than can be recovered from the resulting hydrogen,
quite apart from the cost of handling the bulk product.
Ultimately the sun is the only feasible source of energy that is
mechanicalof mineral resources, whether realised as heat, electricity oraspower. Fusion power is, as always, potential.
Primary energy can be used to directly produce an energy carrier, such
ahydrogen, but to use the energy to produce an intermediate stage may bethanmore practical approach.
A chemical disassociation system could be even less energy efficient
considered.electrolysis, but could be easily and safely distributed, perhaps in a
cartridge form.
The point is that both effectiveness and efficiency have to be
leaders?Is anyone able to put some figures on the potential cost efficiency of a
chemical dissociation system at the point of use, versus the bulk
production and distribution of hydrogen, as promoted by our beloved
carAnd how would the bulk and weight versus range of a water dissociatingpracticehttp://en.wikipedia.org/wiki/Fuel_cell#Fuel_cell_efficiencysystem likely to compare with bulk hydrogen, or batteries?Hydrogen for transport is a non-starter.
Splitting water, 80% efficient.
Fuel cell to electricity, 60% in
Batteries, 90%+http://en.wikipedia.org/wiki/Lithium_ion_battery
--
Dirk
http://www.transcendence.me.uk/- Transcendence UK
Remote Viewing classes in London- Hide quoted text -
- Show quoted text -
The efficiency figures need further description. For example,
conversion of the chemical energy in gasoline to motion of a car
against friction is only about 20%. So 60% sounds pretty good. But
I'll bet that is not the process with 60% efficiency.
Ben
The thing about batteries is not their efficiency or capacity, but their
cost, and that as with explosives, the energy is all together in one place.
More so with super capacitors. A 30KWH battery is more dangerous than a
tankfull of petrol, which needs air to burn. A capacitor with that much
energy would be a bomb! (remember the SF "Interociters"?)
Efficiency may take second place to something that works.
LiFeP
http://www.evworld.com/article.cfm?storyid=979
"Because of its nanophosphate chemistry, A123 asserts that it's battery is the first "intrinsically safe" lithium-ion cell on the market.
"There is no risk for thermal runaway," Fulop claimed, which has been a concern with older lithium chemistries. "This is the first high-power lithium chemistry to offer that benefit." "
It will burn, but not explode.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
Remote Viewing classes in London
.
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- From: Ian Macmillan
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