On Mon, 11 May 2015 20:57:57 +0000 (UTC), Skywise
wrote:
Larry Dighera wrote in
:
On Fri, 8 May 2015 21:28:24 +0000 (UTC), Skywise
wrote:
Larry Dighera wrote in
news
I was thinking it might be necessary to heat the LH2 so that it could
keep up with the fuel demand of the fuel-cell producing the power to
produce the motive thrust.
Stop refridgerating it? LH2 is -423F/-253C.
That brings up an interesting opportunity for an electric power plant:
superconductivity. This liquid hydrogen fuel concept is beginning to
become more interesting...
http://en.wikipedia.org/wiki/Superconductivity
I really think you are completely missing the problem.
It takes energy to do these things. It is not a source of
energy.
It takes energy to make the hydrogen because it doesn't exist
in it's free state naturally on Earth. Currently, most hydrogen
is produced from natural gas, with CO2 as a byproduct.
It takes energy to compress it, or liquify it.
It takes energy to refridgerate it to such low temperatures.
and to keep it there.
Photovoltaic powered electrolysis of H2O would be my choice to produce
hydrogen. It might even power the compressor and condenser to liquefy it also.
Other than the energy used to make the solar cells, there is no energy cost and
no byproducts. Making this practical will take some ingenuity, but
theoretically, I'd suppose it is possible.
Where is all that energy going to come from?
And you will never ever EVER get out of LH2 the amount of energy
that went into producing it.
With free solar power, that isn't much of an issue.
It's a simple numbers game. Balance the books. You're in the red.
On the other hand, if you do find an alternate SOURCE of energy,
one that is so cheap and plentiful and does minimal or no harm
to the environment, then maybe you can look at things like LH2 as
a medium to store and use energy (after solving the CO2 problem),
and all the losses in it's production won't matter because the
actual SOURCE of energy is so cheap and plentiful you don't mind
wasting a bit of it.
Yep.
Nuclear is the only source of producing mass quantities of energy
that I know of,
If energy production is decentralized, mass quantities aren't required. Think
every home with rooftop photovoltaics.
Of course, that won't do for airline operations, but 250 megawatt solar
facilities are in operation in California and Nevada now:
http://investor.firstsolar.com/releasedetail.cfm?ReleaseID=793411, and even
the Air Force has a 14.2 megawatts installation:
http://www.cnet.com/news/air-force-base-in-nevada-goes-solar-with-14-megawatt-array/#!.
but it has it's own inherent risks and challenges,
most of which I think are solvable except for the public relations
side of it. But, it does not emit CO2 which is the major argument
regarding fossil fuels.
You believe the "inherent risks and challenges" are solvable, because they have
been woefully underestimated as have the costs.
The way I see the current state of nuclear is a lot like the oceans. When the
sea is calm, things are fine. But the sea has the potential for ENORMOUS
destruction, as born out recently in the Fukushima tsunami. Despite the sea
wall, the sea managed to cause massive destruction beyond what engineers had
estimated. And there's NOTHING to prevent an even larger tsunami from
occurring in the future.
The nuclear industry has voluntarily created a $12.6-billion insurance fund and
enacted legislation limiting their liability to that amount. The Fukushima
disaster is estimated at $500-billion. And after 29 years hundreds of square
miles of Chernobyl is still uninhabitable. Nuclear plants are continually
venting radio-active products into the environment during normal operation. And
in the event of a containment breach, the spread of radioactivity can be
alarming. Here's what happened as a result of the Chernobyl meltdown:
Chernobyl disaster effects
National and international spread of radioactive substances
Four hundred times more radioactive material was released from Chernobyl
than by the atomic bombing of Hiroshima. The disaster released 1/100 to
1/1000 of the total amount of radioactivity released by nuclear weapons
testing during the 1950s and 1960s.[88] Approximately 100,000 kmē of land
was significantly contaminated with fallout, with the worst hit regions
being in Belarus, Ukraine and Russia.[89] Slighter levels of contamination
were detected over all of Europe except for the Iberian
Peninsula.[16][90][91]
The initial evidence that a major release of radioactive material was
affecting other countries came not from Soviet sources, but from Sweden. On
the morning of 28 April[92] workers at the Forsmark Nuclear Power Plant
(approximately 1,100 km (680 mi) from the Chernobyl site) were found to
have radioactive particles on their clothes.[93]
So, from my point of view, nuclear fission power is far too dangerous for
consideration as a "free" and "clean" power source. Just ask the residents who
have to pay to saw up, and haul away the entire San Onofre power plant. And
without a safe place to store the radioactive waste, it is just plane
irresponsible. And the potential for catastrophe has been under estimated by
several orders of magnitude, just like the potential of the sea.
But the military wants it, and the war profiteers are happy to oblige....
Fusion reactors have been a decade away for the past 5 decades.
How many years passed between the time Leonardo da Vinci conceived of the
helicopter and it's production?
There aren't enough rivers to dam, and it harms ecosystems.
Wind is intermittent and too little. And kills birds.
I recall living under the flight path of LAX in the '50s. You couldn't hold a
conversation at dinner time for the din of arriving B-707s. Today, I reside
very close to KSBA, and the airliners are significantly quieter than the GA
piston aircraft. Progress takes time...
Solar is viable, but only works during the day. It can be scaled
to compensate along with appropriate electricity storage mechanisms
to offset night and cloudy days. Perhaps Tesla's house battery is
a step in this direction? However, solar cells are still too
expensive to force people to switch.
Responsible people are switching voluntarily; no need to force them.
The price of solar panels is dropping all the time. Last I checked, it was
possible to purchase solar panels on eBay for ~$1/watt.
Folks can't see CO2. They
can't feel .2 degrees Celcius. But they CAN see the numbers on
their credit card bills.
Which brings up another point. The energy problem is as much a
human psychology problem as it is a technical problem.
The way I see it, it's more a matter of entrenched wealthy businessman
protecting their cash cows...
To put it bluntly, the vast majority of people don't give a F.
Brian
Fortunately, that is changing ...
So, the use of LH2 to generate electricity with a fuel-cell to drive an
electrical motor that employs superconductivity seem a worthwhile course to
investigate for powering future aircraft. Granted there are currently
obstacles to achieving a viable system, but I don't believe physics precludes
it; only the development of the technology stands in the way.