Re: CAFE Electric Aircraft Symposium Set For May 1

[Larry Dighera]

On Mon, 27 Apr 2015 08:25:02 +1200, george152 > wrote:

>On 27/04/2015 1:58 a.m., Larry Dighera wrote:
>
>> Glaring omission: SOLAR IMPULSE
>> <http://us3.campaign-archive2.com/?u=553e7fdb79a7f1570622b070d&id=5e3b071d05&e=2b92d60fc6>
>> Round the world flight with the Sun as sole fuel source!
>>
>
>
>Thanks for that Larry.
>At present I'm extracting the urine (taking the ****) out of some-one
>who thinks the Solar Impulse is a breakthrough.
>Pointed out that that last leg took them 17 hours.
>Most of the Cessnas and Pipers I fly would do it with 4-6 SOB in 4 hours


You are correct, George. Eric Raymond was flying solely on solar power many
years before the Solar Impulse project began. That said, I know of no other
solar powered aircraft that has succeeded, indeed embarked upon, a
round-the-world flight fueled solely by sunlight as the Solar Impulse has.

Comparing today's electrically powered aircraft to Cessnas and Pipers is a bit
like comparing the Wright Flyer to them; electrically powered aircraft are
still in their infancy of development.

What I found interesting about the symposium was the big names on the roster of
speakers: Airbus, Northrop-Grumman, NASA, Carnegie Mellon University ... It
would seem that electrically powered aircraft are making steady advances in
performance and credibility as they are continuing to be developed and
technology improves.

Personally, I believe that one day the world will look back on the
petroleum-based era of motive power as the "Model T" era, and be thankful for
the development of far more efficient and cleaner electrical power. But then,
as being a "card carrying" IBEW member for over 50 years, and having benefit of
the schooling they provided for four years, I may be a bit biased. :-)

[george152]

On 28/04/2015 4:23 a.m., Larry Dighera wrote:
> On Mon, 27 Apr 2015 08:25:02 +1200, george152 > wrote:
>
>> On 27/04/2015 1:58 a.m., Larry Dighera wrote:
>>
>>> Glaring omission: SOLAR IMPULSE
>>> <http://us3.campaign-archive2.com/?u=553e7fdb79a7f1570622b070d&id=5e3b071d05&e=2b92d60fc6>
>>> Round the world flight with the Sun as sole fuel source!
>>>
>>
>>
>> Thanks for that Larry.
>> At present I'm extracting the urine (taking the ****) out of some-one
>> who thinks the Solar Impulse is a breakthrough.
>> Pointed out that that last leg took them 17 hours.
>> Most of the Cessnas and Pipers I fly would do it with 4-6 SOB in 4 hours
>
>
> You are correct, George. Eric Raymond was flying solely on solar power many
> years before the Solar Impulse project began. That said, I know of no other
> solar powered aircraft that has succeeded, indeed embarked upon, a
> round-the-world flight fueled solely by sunlight as the Solar Impulse has.
>
> Comparing today's electrically powered aircraft to Cessnas and Pipers is a bit
> like comparing the Wright Flyer to them; electrically powered aircraft are
> still in their infancy of development.
>
> What I found interesting about the symposium was the big names on the roster of
> speakers: Airbus, Northrop-Grumman, NASA, Carnegie Mellon University ... It
> would seem that electrically powered aircraft are making steady advances in
> performance and credibility as they are continuing to be developed and
> technology improves.
>
> Personally, I believe that one day the world will look back on the
> petroleum-based era of motive power as the "Model T" era, and be thankful for
> the development of far more efficient and cleaner electrical power. But then,
> as being a "card carrying" IBEW member for over 50 years, and having benefit of
> the schooling they provided for four years, I may be a bit biased. :-)
>

There was an electric aircraft in the 30s.
Had an endurance of 2 hours.
I checked through some of the current machines.
Apart from the self launched sailplanes most are two seaters with a two
hour endurance.
Any cross country would be limited by the reserve requirement. Don't
know what it is in the US but here minimum is 15 minutes.
Not a great range and the recharge will really stuff your day

[Larry Dighera]

On Tue, 28 Apr 2015 08:40:43 +1200, george152 > wrote:

>On 28/04/2015 4:23 a.m., Larry Dighera wrote:
>> On Mon, 27 Apr 2015 08:25:02 +1200, george152 > wrote:
>>
>>> On 27/04/2015 1:58 a.m., Larry Dighera wrote:
>>>
>>>> Glaring omission: SOLAR IMPULSE
>>>> <http://us3.campaign-archive2.com/?u=553e7fdb79a7f1570622b070d&id=5e3b071d05&e=2b92d60fc6>
>>>> Round the world flight with the Sun as sole fuel source!
>>>>
>>>
>>>
>>> Thanks for that Larry.
>>> At present I'm extracting the urine (taking the ****) out of some-one
>>> who thinks the Solar Impulse is a breakthrough.
>>> Pointed out that that last leg took them 17 hours.
>>> Most of the Cessnas and Pipers I fly would do it with 4-6 SOB in 4 hours
>>
>>
>> You are correct, George. Eric Raymond was flying solely on solar power many
>> years before the Solar Impulse project began. That said, I know of no other
>> solar powered aircraft that has succeeded, indeed embarked upon, a
>> round-the-world flight fueled solely by sunlight as the Solar Impulse has.
>>
>> Comparing today's electrically powered aircraft to Cessnas and Pipers is a bit
>> like comparing the Wright Flyer to them; electrically powered aircraft are
>> still in their infancy of development.
>>
>> What I found interesting about the symposium was the big names on the roster of
>> speakers: Airbus, Northrop-Grumman, NASA, Carnegie Mellon University ... It
>> would seem that electrically powered aircraft are making steady advances in
>> performance and credibility as they are continuing to be developed and
>> technology improves.
>>
>> Personally, I believe that one day the world will look back on the
>> petroleum-based era of motive power as the "Model T" era, and be thankful for
>> the development of far more efficient and cleaner electrical power. But then,
>> as being a "card carrying" IBEW member for over 50 years, and having benefit of
>> the schooling they provided for four years, I may be a bit biased. :-)
>>
>
>There was an electric aircraft in the 30s.
>Had an endurance of 2 hours.

First I've heard of it. Are you able to provide any more information about it?


>I checked through some of the current machines.
>Apart from the self launched sailplanes most are two seaters with a two
>hour endurance.
>Any cross country would be limited by the reserve requirement. Don't
>know what it is in the US but here minimum is 15 minutes.
>Not a great range and the recharge will really stuff your day

Yeah. Current electric aeronautical technology is still a bit nascent. Given
the comparatively high energy density of petroleum-based aviation fuels, it's
going to be difficult to achieve comparable endurance with any electric
technology other than perhaps highly pressurized hydrogen feeding a remarkably
efficient fuel cell generator.

The way I see it currently, is that a lighter than air craft, that doesn't
relies on power to maintain altitude, and could possibly be covered in
photovoltaic "fabric" (such technology is still pretty new.) is a reasonable
starting place with a far better probability of success than winged aircraft.

The high efficiency of electric power is somewhat enabling in potentially
replacing internal combustion power plants be they piston or turbine.

[Skywise]

Larry Dighera > wrote in
:

> Yeah. Current electric aeronautical technology is still a bit nascent.
> Given the comparatively high energy density of petroleum-based aviation
> fuels, it's going to be difficult to achieve comparable endurance with
> any electric technology other than perhaps highly pressurized hydrogen
> feeding a remarkably efficient fuel cell generator.

Liquid H: 2,600 WattHours/Liter 39,000 WattHours/Kilogram
Gasoline: 9,000 WattHours/Liter 13,500 WattHours/Kilogram

Gasoline has nearly 3.5 times more energy per volume.

Although liquid hydrogen has nearly 3 times more energy per
unit weight, that does not take into account the mass of the
containment vessel. A liquid hydrogen tank is going to more
than 3 times as massive as a gasoline tank or fuel bladder,
thus resulting in a net loss of energy per unit weight of the
fuel plus it's container.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Larry Dighera]

On Mon, 4 May 2015 02:10:28 +0000 (UTC), Skywise >
wrote:

>Larry Dighera > wrote in
:
>
>> Yeah. Current electric aeronautical technology is still a bit nascent.
>> Given the comparatively high energy density of petroleum-based aviation
>> fuels, it's going to be difficult to achieve comparable endurance with
>> any electric technology other than perhaps highly pressurized hydrogen
>> feeding a remarkably efficient fuel cell generator.
>
>Liquid H: 2,600 WattHours/Liter 39,000 WattHours/Kilogram
>Gasoline: 9,000 WattHours/Liter 13,500 WattHours/Kilogram
>
>Gasoline has nearly 3.5 times more energy per volume.
>
>Although liquid hydrogen has nearly 3 times more energy per
>unit weight, that does not take into account the mass of the
>containment vessel. A liquid hydrogen tank is going to more
>than 3 times as massive as a gasoline tank or fuel bladder,
>thus resulting in a net loss of energy per unit weight of the
>fuel plus it's container.
>
>Brian


Thank you for that information. I hadn't seen it before.

I'll agree that a liquid H2 tank will likely be more massive than today's
gasoline tanks, but couldn't liquid H2 be stored in a Styrofoam containing
vessel?

Aren't the relative efficiencies of electrical propulsion vs internal
combustion powerplants being overlooked here?

[Vaughn]

On 5/3/2015 10:10 PM, Skywise wrote:
> Although liquid hydrogen has nearly 3 times more energy per
> unit weight, that does not take into account the mass of the
> containment vessel. A liquid hydrogen tank is going to more
> than 3 times as massive as a gasoline tank or fuel bladder,
> thus resulting in a net loss of energy per unit weight of the
> fuel plus it's container.

I'm not sure where you got that information from, but it's wrong.
Compressed hydrogen takes a heavy tank because of the pressure.

On the other hand, liquid hydrogen need not be under pressure, so it
does not need a massive tank. However, cryogenic fuels have their own
issues! What a cryogenic fuel tank needs that is different from other
liquid fuels is insulation. That insulation need not be heavy, but it
will take up valuable volume in your airframe. Also, cryogenic tanks
are always venting unless you have heavy, expensive power-hungry
refrigeration equipment aboard. So that means that your liquid
hydrogen-fueled airplane could be assumed to be sitting in a cloud of
flammable gaseous fuel whenever it is fueled and sitting on the ground.
No thanks!

[Skywise]

Larry Dighera > wrote in
:

> I'll agree that a liquid H2 tank will likely be more massive than
> today's gasoline tanks, but couldn't liquid H2 be stored in a Styrofoam
> containing vessel?

The problem is either temperature or pressure, or both.

Liquid H2 is cryogenic. It doesn't exert pressure any more than
water does in a tank. But it has to be kept at -423F or -253C.

Styorofoam would just take up space.

If the idea is to avoid the crygenic temperatures, you then
need to fight the pressure. If I did my math right, and read
the phase diagram for hydrogen right, then liquid H2 at room
temperature has a pressure of about 2.5 million atmospheres.
There's no tank in the world that can hold that back.

Pressurized hydrogen at room temperature is just compressed
gaseous hydrogen. So a vehicle with that is like carrying around
a bunch of scuba tanks, which IIRC are only 3000-4000 psi or
about 200 to 270 atmospheres pressure, and look at how heavy
those are!!

I have heard about efforts to store hydrogen in metallic foams
but don't know the state of that work.

The problem is, the energy is in the hydrogen atoms. The more
atoms you have, the more energy you have. So if you want a lot
of energy, you have to cram a bunch of hydrogen atoms together
in a small space.

Now here's the killer. The properties of hydrocarbon molecules
is such that gasoline has a higher density of hydrogen atoms
than even liquid hydrogen!!! There's more hydrogen atoms per
unit volume. That's why gasoline has a 3x higher energy/density
value than liquid hydrogen. There are simply more hydrogen atoms
and therefore more energy.



> Aren't the relative efficiencies of electrical propulsion vs internal
> combustion powerplants being overlooked here?

My thought on electrical propulsion is, how is the electricity
produced in the first place? One rule of reality is that every
time you convert one form of energy to another, there are losses,
eventually ending up as heat. Basic Laws of Thermodynamics stuff.

Internal combustion (or turbine) engines burn the fuel and directly
convert it to mechanical work. That's bascially only one stage of
conversion to have any conversion losses.

Or, burn the fuel to drive a generator (loss 1), which generates
electricity (loss 2), which is then stored in a battery (loss 3),
which then is drawn from the battery (loss 4) to power an electic
motor (loss 5).

All those conversion losses add up. That's why gasoline is so hard
to beat. Doesn't matter if you like fossil fuels or hate it, it's
a simple fact that right now and in the forseable future, it's the
most efficient energy storage mechanism around.

The only alternative I see is to use elctricity from batteries
but generate the electricity by some other means than fossil fuels.
After all, isn't the whole point of this? to stop burning oil and
polluting the atmosphere? Burning the fossil fuels to generate
electricity to run cars and busses and planes only changes the
location of where it's burned. All these people driving their
electric cars feeling smug about themselves are not realizing that
the electricity is most likely coming from a coal fired generating
plant. And due to conversion losses, there's a good chance they
are actually increasing their "carbon footprint" than decreasing it.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Skywise]

Vaughn > wrote in :

> On 5/3/2015 10:10 PM, Skywise wrote:
>> Although liquid hydrogen has nearly 3 times more energy per
>> unit weight, that does not take into account the mass of the
>> containment vessel. A liquid hydrogen tank is going to more
>> than 3 times as massive as a gasoline tank or fuel bladder,
>> thus resulting in a net loss of energy per unit weight of the
>> fuel plus it's container.
>
> I'm not sure where you got that information from, but it's wrong.

http://www.tinaja.com/glib/energfun.pdf

The numbers can be confirmed by other sources.

But I think you misread what I wrote.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Larry Dighera]

On Mon, 04 May 2015 08:33:26 -0400, Vaughn > wrote:

>On the other hand, liquid hydrogen need not be under pressure, so it
>does not need a massive tank. However, cryogenic fuels have their own
>issues! What a cryogenic fuel tank needs that is different from other
>liquid fuels is insulation. That insulation need not be heavy, but it
>will take up valuable volume in your airframe. Also, cryogenic tanks
>are always venting unless you have heavy, expensive power-hungry
>refrigeration equipment aboard. So that means that your liquid
>hydrogen-fueled airplane could be assumed to be sitting in a cloud of
>flammable gaseous fuel whenever it is fueled and sitting on the ground.
> No thanks!

I hadn't considered the explosive environment created by venting liquid
hydrogen. How is that dealt with by suppliers, laboratories and users today?

Perhaps the venting H2 could be captured and run through the fuel-cell and the
resulting electric power stored in batteries for future use to preclude the
explosive atmosphere forming.

I'm wondering if the heat produced by a fuel-cell could be used to change the
liquid H2 into the gaseous phase, and if the resulting cooling of the fuel-cell
will contribute to its efficiency.

[Skywise]

Larry Dighera > wrote in
:

> I hadn't considered the explosive environment created by venting liquid
> hydrogen. How is that dealt with by suppliers, laboratories and users
> today?
>
> Perhaps the venting H2 could be captured and run through the fuel-cell
> and the resulting electric power stored in batteries for future use to
> preclude the explosive atmosphere forming.

Just more equipment that can fail and adds weight and cost. I'm
sure the airlines would like that. Or, would you like that on
your car?



> I'm wondering if the heat produced by a fuel-cell could be used to
> change the liquid H2 into the gaseous phase, and if the resulting
> cooling of the fuel-cell will contribute to its efficiency.

Why would you want to heat liquid H2? The reason tanks vent is
because it's boiling off. It's very difficult to insulate a tank
to LH2 temperatures, so some of it boils off. If you don't vent
it... KABOOOM!

Remember Challenger? That's what happens when the tank breaches.

Speaking of rockets, ever notice how they are constantly venting
while on the pad? They close the valves just before lift-off. If
the launch is delayed the valves are reopened to prevent too much
pressure from building. After launch it's not a problem because
the fuel is being consumed fast enough.

Personally, I find the whole argument on hydrogen as a replacement
for gasoline a joke. It's basic physics. So unless the laws of
physics go out the window.... Well, there are those who think
science and basic physics are a conspiracy to keep the truth from
being revealed... But I'm not assuming anyone here is in that camp.
Yet.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Larry Dighera]

On Fri, 8 May 2015 01:39:59 +0000 (UTC), Skywise >
wrote:

>Larry Dighera > wrote in
:
>
>> I hadn't considered the explosive environment created by venting liquid
>> hydrogen. How is that dealt with by suppliers, laboratories and users
>> today?
>>
>> Perhaps the venting H2 could be captured and run through the fuel-cell
>> and the resulting electric power stored in batteries for future use to
>> preclude the explosive atmosphere forming.
>
>Just more equipment that can fail and adds weight and cost. I'm
>sure the airlines would like that. Or, would you like that on
>your car?
>

I wasn't considering electric airliners yet; I was thinking more along the
lines of GA-sized aircraft. I'm still curious how venting H2 is kept from
producing an explosive atmosphere in laboratories and at the gas plants where
it is produced. Surely the technology exists...

>
>> I'm wondering if the heat produced by a fuel-cell could be used to
>> change the liquid H2 into the gaseous phase, and if the resulting
>> cooling of the fuel-cell will contribute to its efficiency.
>
>Why would you want to heat liquid H2?

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.

>The reason tanks vent is because it's boiling off. It's very difficult to
>insulate a tank to LH2 temperatures, so some of it boils off.

It would be interesting to know just how difficult it is to insulate a LH2
vessel, so that the boil-off rate is reasonably slow.

>If you don't vent it... KABOOOM!

Yeah. I recall the resounding POP that occurs when a burning splint is
inserted into the inverted test tube containing the evolved H2 from
electrolysis. It's a definite issue, as is the explosive atmosphere created by
venting gasoline vapors. But, obviously methods have been successfully
developed to deal with it.

>
>Remember Challenger? That's what happens when the tank breaches.
>

My recollection was that the seals on the Solid Rocket Boosters on the sides of
the big central O2-H2 tank had failed, and the hot SRB gases had breached the
big tank. I wasn't aware of an H2 venting issue.

>Speaking of rockets, ever notice how they are constantly venting
>while on the pad? They close the valves just before lift-off. If
>the launch is delayed the valves are reopened to prevent too much
>pressure from building. After launch it's not a problem because
>the fuel is being consumed fast enough.
>

Agreed.

Ever notice the main rocket nozzles suddenly ice-up shortly after ignition? I
believe that's a result of the cold liquid combustion gases being routed
through tubing coiled around the rocket motors to keep them from melting and
assist in atomizing the gases, so that they will react more readily. Just a
guess.

>Personally, I find the whole argument on hydrogen as a replacement
>for gasoline a joke.

The limited research I conducted years ago seemed to suggest that there wasn't
much else that approached the energy density of gasoline/kerosene. So, while
perhaps not ideal, hydrogen is a somewhat viable alternative to petroleum, that
has the potential to provide efficiencies several times better than the ~30%
efficiency obtained with internal combustion power plants. If you consider
that only one third the fuel will be required to achieve the current
performance, the numbers begin to make more sense.

With 70% of the energy blowing out the exhaust as heat, internal combustion
engine efficiency is comparable to an incandescent lamp that consumes ~90% of
its energy usage to produce heat, and only ~10% to produce light. LEDs, on the
other hand, can be 90% more efficient than tungsten filament lamps, and they
last many times longer too.

>It's basic physics. So unless the laws of physics go out the window....

I understand what you are saying, and I agree; the solution isn't obvious, but
it may be possible. Apparently a lot of large commercial entities seem to
think so...

> Well, there are those who think science and basic physics are a conspiracy to
> keep the truth from being revealed... But I'm not assuming anyone here is in
> that camp. Yet.
>
>Brian


Hey. Let's leave T. Cruz and Santorum out of this discussion. :-)


--
Irrational acts are ultimately founded on irrational beliefs.
-- Larry Dighera

[Skywise]

Larry Dighera > wrote in
:

> I wasn't considering electric airliners yet; I was thinking more along
> the lines of GA-sized aircraft. I'm still curious how venting H2 is
> kept from producing an explosive atmosphere in laboratories and at the
> gas plants where it is produced. Surely the technology exists...

It's burned off to prevent just such a situation.


>>Why would you want to heat liquid H2?
>
> 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. It doesn't take much
to heat it up. That's why the tanks vent.



>>The reason tanks vent is because it's boiling off. It's very difficult
>>to insulate a tank to LH2 temperatures, so some of it boils off.
>
> It would be interesting to know just how difficult it is to insulate a
> LH2 vessel, so that the boil-off rate is reasonably slow.

I'm sure you could eliminated venting altogether with s sufficiently
strong tank and MAINTAINED crygenic cooling.



>>Remember Challenger? That's what happens when the tank breaches.
>>
>
> My recollection was that the seals on the Solid Rocket Boosters on the
> sides of the big central O2-H2 tank had failed, and the hot SRB gases
> had breached the big tank. I wasn't aware of an H2 venting issue.

My point was the size of the KABOOOM.

Perhaps a better example.... Hindenburg.





> Ever notice the main rocket nozzles suddenly ice-up shortly after
> ignition? I believe that's a result of the cold liquid combustion gases
> being routed through tubing coiled around the rocket motors to keep them
> from melting and assist in atomizing the gases, so that they will react
> more readily. Just a guess.

You're correct.

http://www.nasa.gov/mission_pages/constellation/multimedia/cece.html

https://www.youtube.com/watch?v=5QJNnTRRLOo

Although not all rocket engines do this.



> With 70% of the energy blowing out the exhaust as heat, internal
> combustion engine efficiency is comparable to an incandescent lamp that
> consumes ~90% of its energy usage to produce heat, and only ~10% to
> produce light. LEDs, on the other hand, can be 90% more efficient than
> tungsten filament lamps, and they last many times longer too.

Good analogy. But that is an example not of more efficient energy
production, but more efficient energy consumption. Although both
are needed in the grand scheme of things, IMO.

What's to say we can't find a more efficient way to consume fossil
fuels? Although it tends to sound conspiracy theory like, I think
there is some merit to the notion that more fuel efficiency in
cars is being held back for monetary reasons. It is a fact that
vehicles have been designed that get far higher MPG than you
typically find on the road. Why aren't they being sold?

For example, I just found the following on a VW diesel hybrid
capable of nearly 300 MPG.

http://hereandnow.wbur.org/2014/09/17/volkswagen-fuel-efficiency

http://www.wired.com/2013/05/volkswagen-xl1-driven/

This leads to another point I learned myself while driving. People
race from red light to red light. Not don't get me wrong. I like
to drive fast just like anyone else. But what I learned to do is
to not make it a drag race. I still go ten over on the streets,
cruise 80-85mph on the freeway (I'm in LA). I just don't stomp
on the gas pedal to get there.

I did a comparison on this change in driving style. I increased
my MPG by at least 10% just by changing the way I accelerate.
Funny thing is, I often find myself pulling up to the same cars
at the light... those racing off the line.




>>It's basic physics. So unless the laws of physics go out the window....
>
> I understand what you are saying, and I agree; the solution isn't
> obvious, but it may be possible. Apparently a lot of large commercial
> entities seem to think so...

I guess I'm arguing against the public perception. There's a lot
of bad info out there. I don't profess to be any kind of expert
myself, but I know what I know, otherwise I shut up. So many
people think it's a simple thing to just convert all our cars
to some other form of energy and overnight we can change the
world. Well, we can't. We've had a hundred years to develop IC
engines. It may take another hundred years to replace them. What
happens in the lab does not always translate to real-world
practical application.

Can an alternative be found? I'm sure of it.



>> Well, there are those who think science and basic physics are a
>> conspiracy to keep the truth from being revealed... But I'm not
>> assuming anyone here is in that camp. Yet.
>>
> Hey. Let's leave T. Cruz and Santorum out of this discussion. :-)

Hey, the other side of the aisle isn't much smarter. Two sides
of the same coin if you ask me.

hehehe... well, there's a web forum that I visit regularly that
is chock full of nutters. Needless to say my actual participation
has been decreasing over time as I realize the futility of even
existing in such an environment.

The New Dark Ages are upon us.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Vaughn]

On 5/8/2015 2:30 PM, Larry Dighera wrote:
>
>> >Personally, I find the whole argument on hydrogen as a replacement
>> >for gasoline a joke.
> The limited research I conducted years ago seemed to suggest that there wasn't
> much else that approached the energy density of gasoline/kerosene. So, while
> perhaps not ideal, hydrogen is a somewhat viable alternative to petroleum, that
> has the potential to provide efficiencies several times better than the ~30%
> efficiency obtained with internal combustion power plants. If you consider
> that only one third the fuel will be required to achieve the current
> performance, the numbers begin to make more sense.
>
> With 70% of the energy blowing out the exhaust as heat, internal combustion
> engine efficiency is comparable to an incandescent lamp that consumes ~90% of
> its energy usage to produce heat, and only ~10% to produce light. LEDs, on the
> other hand, can be 90% more efficient than tungsten filament lamps, and they
> last many times longer too.
>
Simply put, the problem with using hydrogen as a fuel is that we have no
natural source of it in unattached gaseous form. So we have to MAKE
hydrogen by reforming it from natural gas, or by some even more
energy-hungry method such as electrolysis of water.

So while hydrogen can be used as a fuel, it is not a SOURCE of energy
such as natural gas or gasoline is. Hydrogen is only a CARRIER of
energy (much like our electrical utilities are a carrier of energy, not
a source of energy). In the process of converting "something" to
hydrogen, you never have 100% efficiency, so on a whole-cycle macro
scale the efficiency picture of hydrogen can look pretty dismal.

Also, an article might extol the clean burning properties of hydrogen in
an engine or fuel cell, while failing the mention the pollution produced
by the manufacture of hydrogen.

[[email protected]]

Vaughn > wrote:
> On 5/8/2015 2:30 PM, Larry Dighera wrote:
>>
>>> >Personally, I find the whole argument on hydrogen as a replacement
>>> >for gasoline a joke.
>> The limited research I conducted years ago seemed to suggest that there wasn't
>> much else that approached the energy density of gasoline/kerosene. So, while
>> perhaps not ideal, hydrogen is a somewhat viable alternative to petroleum, that
>> has the potential to provide efficiencies several times better than the ~30%
>> efficiency obtained with internal combustion power plants. If you consider
>> that only one third the fuel will be required to achieve the current
>> performance, the numbers begin to make more sense.
>>
>> With 70% of the energy blowing out the exhaust as heat, internal combustion
>> engine efficiency is comparable to an incandescent lamp that consumes ~90% of
>> its energy usage to produce heat, and only ~10% to produce light. LEDs, on the
>> other hand, can be 90% more efficient than tungsten filament lamps, and they
>> last many times longer too.
>>
> Simply put, the problem with using hydrogen as a fuel is that we have no
> natural source of it in unattached gaseous form. So we have to MAKE
> hydrogen by reforming it from natural gas, or by some even more
> energy-hungry method such as electrolysis of water.
>
> So while hydrogen can be used as a fuel, it is not a SOURCE of energy
> such as natural gas or gasoline is. Hydrogen is only a CARRIER of
> energy (much like our electrical utilities are a carrier of energy, not
> a source of energy). In the process of converting "something" to
> hydrogen, you never have 100% efficiency, so on a whole-cycle macro
> scale the efficiency picture of hydrogen can look pretty dismal.
>
> Also, an article might extol the clean burning properties of hydrogen in
> an engine or fuel cell, while failing the mention the pollution produced
> by the manufacture of hydrogen.

If you burn hydrogen in an engine, you get lots of NOX byproducts, i.e.
smog, because air is mostly nitrogen and hydrogen has a very high
flame temperature.

Fuel cells do not have that problem as the temperatured involved are
much lower.



--
Jim Pennino

[Vaughn]

On 5/9/2015 4:32 PM, wrote:
>
> If you burn hydrogen in an engine, you get lots of NOX byproducts, i.e.
> smog, because air is mostly nitrogen and hydrogen has a very high
> flame temperature.
>
> Fuel cells do not have that problem as the temperatured involved are
> much lower.
>
>
>
Yes, but my point was that you are still left with the problem of the
pollution and greenhouse gas generated by the production of your "clean"
hydrogen fuel.

Besides, for at least the last 30 years, mass consumer fuel cells have
been "just around the corner". Even if they suddenly became practical
and economical, we would still be left with the huge problems involved
in producing and distributing hydrogen.

You can wave your arms and talk about fuel cells all day, but the
problems with hydrogen won't go away. Hydrogen is not an energy source.
To make hydrogen, you make pollution.

[[email protected]]

Vaughn > wrote:
> On 5/9/2015 4:32 PM, wrote:
>>
>> If you burn hydrogen in an engine, you get lots of NOX byproducts, i.e.
>> smog, because air is mostly nitrogen and hydrogen has a very high
>> flame temperature.
>>
>> Fuel cells do not have that problem as the temperatured involved are
>> much lower.
>>
>>
>>
> Yes, but my point was that you are still left with the problem of the
> pollution and greenhouse gas generated by the production of your "clean"
> hydrogen fuel.
>
> Besides, for at least the last 30 years, mass consumer fuel cells have
> been "just around the corner". Even if they suddenly became practical
> and economical, we would still be left with the huge problems involved
> in producing and distributing hydrogen.
>
> You can wave your arms and talk about fuel cells all day, but the
> problems with hydrogen won't go away. Hydrogen is not an energy source.
> To make hydrogen, you make pollution.

And my point was if you BURN hydrogen, you make pollution.



--
Jim Pennino

[Skywise]

wrote in :

> Vaughn > wrote:
>> On 5/9/2015 4:32 PM, wrote:
>>>
>>> If you burn hydrogen in an engine, you get lots of NOX byproducts,
>>> i.e. smog, because air is mostly nitrogen and hydrogen has a very high
>>> flame temperature.
>>>
>>> Fuel cells do not have that problem as the temperatured involved are
>>> much lower.
>>>
>>>
>>>
>> Yes, but my point was that you are still left with the problem of the
>> pollution and greenhouse gas generated by the production of your
>> "clean" hydrogen fuel.
>>
>> Besides, for at least the last 30 years, mass consumer fuel cells have
>> been "just around the corner". Even if they suddenly became practical
>> and economical, we would still be left with the huge problems involved
>> in producing and distributing hydrogen.
>>
>> You can wave your arms and talk about fuel cells all day, but the
>> problems with hydrogen won't go away. Hydrogen is not an energy
>> source.
>> To make hydrogen, you make pollution.
>
> And my point was if you BURN hydrogen, you make pollution.

You are BOTH right.

And a similar argument can be made for going all electric. How
do you make electricity? Right now, most of it is made by BURNING
hydrocarbons.

Moving to electric powered vehicles only shifts the location of
the burning from the vehicle to the electric power plant.

The only way to make electric vehicles viable from a 'pollution
elimination' point of view is to ALSO generate the electricity
from some other method than burning hydrocarbons.

As Vaughn pointed out, we have to find an alternate SOURCE of
energy, not an alternate medium by which to store it. Hydrocarbons
are a source of energy. We get more energy out of hydrocarbons
than we put in to extract it. We don't have to make it. Although
there is the argument about how much is left.

The problem is finding a viable alternate source of energy to
replace hydrocarbons. Ones that can produce energy on par with,
and for future growth eventually exceed the scale of what we get
out of hydrocarbons.

And then there's the whole problem of upgrading the power grid to
handle everyone plugging in their e-car's without the wires glowing.
The alternative to that may well be distributed energy generation.

Replacing hydrocarbons for transportation use is not a simple
or singular problem. At the risk of sounding cliche, it will
require a paradigm shift in the way energy is produced, distributed,
and consumed, and it will have to be adopted by everyone to make
it work.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Dave Doe]

In article >, ,
says...
>
> Vaughn > wrote:
> > On 5/9/2015 4:32 PM, wrote:
> >>
> >> If you burn hydrogen in an engine, you get lots of NOX byproducts, i.e.
> >> smog, because air is mostly nitrogen and hydrogen has a very high
> >> flame temperature.
> >>
> >> Fuel cells do not have that problem as the temperatured involved are
> >> much lower.
> >>
> >>
> >>
> > Yes, but my point was that you are still left with the problem of the
> > pollution and greenhouse gas generated by the production of your "clean"
> > hydrogen fuel.
> >
> > Besides, for at least the last 30 years, mass consumer fuel cells have
> > been "just around the corner". Even if they suddenly became practical
> > and economical, we would still be left with the huge problems involved
> > in producing and distributing hydrogen.
> >
> > You can wave your arms and talk about fuel cells all day, but the
> > problems with hydrogen won't go away. Hydrogen is not an energy source.
> > To make hydrogen, you make pollution.
>
> And my point was if you BURN hydrogen, you make pollution.
>
>

Water is pollution?

I think you either need to get your chemistry right, or define
"hydrogen" - or perhaps, what you are burning. Hydrocarbons?

--
Duncan.

[Skywise]

Dave Doe > wrote in
:

> Water is pollution?
>
> I think you either need to get your chemistry right, or define
> "hydrogen" - or perhaps, what you are burning. Hydrocarbons?

Burning hydrogen with pure oxygen produces only water vapor.
For example, LH2 and O2 rocket engines such as the Shuttle's.

Burning hydrogen with 'air' also produces other compounds,
including nitrous oxides (smog, harmful to humans). 'Air' is
not pure oxygen.

Check your chemistry. ;)

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Dave Doe]

In article >, ,
Skywise says...
>
> Dave Doe > wrote in
> :
>
> > Water is pollution?
> >
> > I think you either need to get your chemistry right, or define
> > "hydrogen" - or perhaps, what you are burning. Hydrocarbons?
>
> Burning hydrogen with pure oxygen produces only water vapor.
> For example, LH2 and O2 rocket engines such as the Shuttle's.
>
> Burning hydrogen with 'air' also produces other compounds,
> including nitrous oxides (smog, harmful to humans). 'Air' is
> not pure oxygen.
>
> Check your chemistry. ;)

Oh I have! Hence the question. I'm sure you've heard of Oxyhydrogen
plants (as in Oxyacetalene plants).

--
Duncan.

[[email protected]]

Dave Doe > wrote:
> In article >, ,
> says...
>>
>> Vaughn > wrote:
>> > On 5/9/2015 4:32 PM, wrote:
>> >>
>> >> If you burn hydrogen in an engine, you get lots of NOX byproducts, i.e.
>> >> smog, because air is mostly nitrogen and hydrogen has a very high
>> >> flame temperature.
>> >>
>> >> Fuel cells do not have that problem as the temperatured involved are
>> >> much lower.
>> >>
>> >>
>> >>
>> > Yes, but my point was that you are still left with the problem of the
>> > pollution and greenhouse gas generated by the production of your "clean"
>> > hydrogen fuel.
>> >
>> > Besides, for at least the last 30 years, mass consumer fuel cells have
>> > been "just around the corner". Even if they suddenly became practical
>> > and economical, we would still be left with the huge problems involved
>> > in producing and distributing hydrogen.
>> >
>> > You can wave your arms and talk about fuel cells all day, but the
>> > problems with hydrogen won't go away. Hydrogen is not an energy source.
>> > To make hydrogen, you make pollution.
>>
>> And my point was if you BURN hydrogen, you make pollution.
>>
>>
>
> Water is pollution?
>
> I think you either need to get your chemistry right, or define
> "hydrogen" - or perhaps, what you are burning. Hydrocarbons?

Air is 78% nitrogen.

Air is used as the oxidizer in an engine.

At high temperatures, i.e. inside an engine, the nitrogen combines
with the excess oxygen to produce NOx; mostly NO and NO2.

It does not matter what is actually "burning", it is the temperature
that causes the reaction and hydrogen has a very high flame temperature.

As hydrocarbons as a rule do not contain nitrogen, where do you think
the NOx emmisions come from?


--
Jim Pennino

[[email protected]]

Dave Doe > wrote:
> In article >, ,
> Skywise says...
>>
>> Dave Doe > wrote in
>> :
>>
>> > Water is pollution?
>> >
>> > I think you either need to get your chemistry right, or define
>> > "hydrogen" - or perhaps, what you are burning. Hydrocarbons?
>>
>> Burning hydrogen with pure oxygen produces only water vapor.
>> For example, LH2 and O2 rocket engines such as the Shuttle's.
>>
>> Burning hydrogen with 'air' also produces other compounds,
>> including nitrous oxides (smog, harmful to humans). 'Air' is
>> not pure oxygen.
>>
>> Check your chemistry. ;)
>
> Oh I have! Hence the question. I'm sure you've heard of Oxyhydrogen
> plants (as in Oxyacetalene plants).

Those are not engines and an oxygen/hydrogen flame exposed to air produces
NOx through the temperatures involved.

It is purely an effect of heating air to a temperature sufficient for
the reaction; the heat source is irrelevant.

--
Jim Pennino

[Skywise]

wrote in :

> It is purely an effect of heating air to a temperature sufficient for
> the reaction; the heat source is irrelevant.

Good point. For example, in the following nuclear test footage,
the red/brown cloud around the stem of the mushroom is nitrous
oxides caused by the heat of the fireball. It's almost literally
"burning the air".

https://www.youtube.com/watch?v=-WsouJ4YzO4

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Larry Dighera]

On Fri, 8 May 2015 21:28:24 +0000 (UTC), Skywise >
wrote:

>Larry Dighera > wrote in
:

>>
>> 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>

[Skywise]

Larry Dighera > wrote in
:

> On Fri, 8 May 2015 21:28:24 +0000 (UTC), Skywise
> > wrote:
>
>>Larry Dighera > wrote in
:
>
>>>
>>> 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.

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.

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.

Nuclear is the only source of producing mass quantities of energy
that I know of, 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.

Fusion reactors have been a decade away for the past 5 decades.

There aren't enough rivers to dam, and it harms ecosystems.

Wind is intermittent and too little. And kills birds.

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. 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. To put it
bluntly, the vast majority of people don't give a F.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Larry Dighera]

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
:
>>
>>>>
>>>> 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 km² 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.

[Vaughn]

On 5/14/2015 1:49 PM, Larry Dighera wrote:
>> 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.
>
>> >
Sorry, but there is no free energy, and there is no totally clean
energy, not even solar. At present, there isn't enough solar energy to
go around. There isn't likely to EVER be enough solar energy to go
around, that's also true of wind and hydro power.

More importantly, if we divert solar energy from the grid to make
hydrogen, then we must make up the difference from somewhere else, which
means burning more fuel. So there is no advantage to diverting "clean"
energy towards something like producing hydrogen, whilst we are burning
coal (or whatever) to make grid power. Energy is energy! Wasting
energy is always a dirty thing to do, even if it's solar. And the
hydrogen energy cycle is inherently wasteful.

[Larry Dighera]

On Thu, 14 May 2015 14:14:43 -0400, Vaughn > wrote:

>On 5/14/2015 1:49 PM, Larry Dighera wrote:
>>> 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.
>>
>>>
>
>Sorry, but there is no free energy,
>

Agreed. I don't think that is at issue here.

>
>and there is no totally clean energy, not even solar.
>

Aside from the waste products associated with the production of solar cells,
I'm not aware of any polluting products emitted by photovoltaic electricity
generation.

>
>At present, there isn't enough solar energy to go around.
>

Mmmm... When it isn't cloudy, there's about 1KW per square meter. It would
seem, that if you've got the land area, there's more than enough solar energy
"to go around", at lease here in southern California. What makes you say that?
Are you saying, that there currently hasn't been enough solar energy generating
stations built to supply the entire nation/world?

>
>There isn't likely to EVER be enough solar energy to go around,
>

Are you able to cite a credible source that supports that assertion? What
leads you to believe that?

>
>that's also true of wind and hydro power.
>

Are you intimating that petroleum based electric generation is the sole
technology that is able to supply the world's needs?

Again, are you able to cite a credible source that supports your an opinion?

>
>More importantly, if we divert solar energy from the grid to make
>hydrogen, then we must make up the difference from somewhere else, which
>means burning more fuel. So there is no advantage to diverting "clean"
>energy towards something like producing hydrogen, whilst we are burning
>coal (or whatever) to make grid power.
>

I wasn't suggesting that grid electricity be used to electrolyze H2O. I was
thinking that solar cells on the roof of a home might be employed electrolyze
water to produce H2 and O2 that would be stored, and used to produce
electricity at a later date.

>
>Energy is energy! Wasting energy is always a dirty thing to do, even if
>it's solar.
>

So, you're saying, that when the Sun is shining on bear earth, we are doing a
"dirty thing" by not capturing the solar energy? Or am I missing your point?

>
>And the hydrogen energy cycle is inherently wasteful.
>

It is true that electrolysis of H2O is not too efficient yet. Until recently
fuel-cell technology hasn't been too efficient either (about 30%). but when I
visited the 2014 Consumer Electronics Show in Las Vegas, an automotive engineer
assured me that they had increased fuel-cell efficiency to 60%, so presumably
the art is making strides toward increasing efficiency. And, if/when H2 power
becomes more mainstream, I would expect the resulting increase in R&D funding
to continue that trend.

How efficient is distilling petroleum into gasoline/kerosene? How efficient
are internal combustion engines piston and turbine?

I appreciate your interest in the subject, but I'm at a loss to understand your
points. And without any supporting research studies or hard data, I'm unable
to put much credence in your unsupported assertions.

Please tell me more about what you KNOW about this subject.

[Larry Dighera]

Hello Brian,

You seem to have firm grasp of the physics involved. Are you able to suggest
how efficient an electric power system powered by LH2 would have to be to
offset the power density difference from gasoline/kerosene?

Larry


On Mon, 4 May 2015 22:27:45 +0000 (UTC), Skywise >
wrote:

>Larry Dighera > wrote in
:
>
>> I'll agree that a liquid H2 tank will likely be more massive than
>> today's gasoline tanks, but couldn't liquid H2 be stored in a Styrofoam
>> containing vessel?
>
>The problem is either temperature or pressure, or both.
>
>Liquid H2 is cryogenic. It doesn't exert pressure any more than
>water does in a tank. But it has to be kept at -423F or -253C.
>
>Styorofoam would just take up space.
>
>If the idea is to avoid the crygenic temperatures, you then
>need to fight the pressure. If I did my math right, and read
>the phase diagram for hydrogen right, then liquid H2 at room
>temperature has a pressure of about 2.5 million atmospheres.
>There's no tank in the world that can hold that back.
>
>Pressurized hydrogen at room temperature is just compressed
>gaseous hydrogen. So a vehicle with that is like carrying around
>a bunch of scuba tanks, which IIRC are only 3000-4000 psi or
>about 200 to 270 atmospheres pressure, and look at how heavy
>those are!!
>
>I have heard about efforts to store hydrogen in metallic foams
>but don't know the state of that work.
>
>The problem is, the energy is in the hydrogen atoms. The more
>atoms you have, the more energy you have. So if you want a lot
>of energy, you have to cram a bunch of hydrogen atoms together
>in a small space.
>
>Now here's the killer. The properties of hydrocarbon molecules
>is such that gasoline has a higher density of hydrogen atoms
>than even liquid hydrogen!!! There's more hydrogen atoms per
>unit volume. That's why gasoline has a 3x higher energy/density
>value than liquid hydrogen. There are simply more hydrogen atoms
>and therefore more energy.
>
>
>
>> Aren't the relative efficiencies of electrical propulsion vs internal
>> combustion powerplants being overlooked here?
>
>My thought on electrical propulsion is, how is the electricity
>produced in the first place? One rule of reality is that every
>time you convert one form of energy to another, there are losses,
>eventually ending up as heat. Basic Laws of Thermodynamics stuff.
>
>Internal combustion (or turbine) engines burn the fuel and directly
>convert it to mechanical work. That's bascially only one stage of
>conversion to have any conversion losses.
>
>Or, burn the fuel to drive a generator (loss 1), which generates
>electricity (loss 2), which is then stored in a battery (loss 3),
>which then is drawn from the battery (loss 4) to power an electic
>motor (loss 5).
>
>All those conversion losses add up. That's why gasoline is so hard
>to beat. Doesn't matter if you like fossil fuels or hate it, it's
>a simple fact that right now and in the forseable future, it's the
>most efficient energy storage mechanism around.
>
>The only alternative I see is to use elctricity from batteries
>but generate the electricity by some other means than fossil fuels.
>After all, isn't the whole point of this? to stop burning oil and
>polluting the atmosphere? Burning the fossil fuels to generate
>electricity to run cars and busses and planes only changes the
>location of where it's burned. All these people driving their
>electric cars feeling smug about themselves are not realizing that
>the electricity is most likely coming from a coal fired generating
>plant. And due to conversion losses, there's a good chance they
>are actually increasing their "carbon footprint" than decreasing it.
>
>Brian

[Skywise]

Larry Dighera > wrote in
:

> Hello Brian,
>
> You seem to have firm grasp of the physics involved. Are you able to
> suggest how efficient an electric power system powered by LH2 would have
> to be to offset the power density difference from gasoline/kerosene?

A quick disclaimer.... I don't have any degrees in this stuff or
work with it. I just happen to be very interested in the sciences
in general and have taught myself a few things over the years.
Having said that, I try very hard to check my facts and figures
before I say anything. I have an allergy to foot-in-mouth disease.

On to your question....

Per numbers in http://www.tinaja.com/glib/energfun.pdf

Liquid H2 has an energy density of 2600 Watt-hours/liter.
Gasoline is 9000 Watt-hours/liter.

[I used energy density per volume rather than per mass
because that's the limiting factor in any vehicle, the
volume of the 'gas tank']

If we make an assumption for discussion's sake that an LH2
powered system were 100% efficient, then the gasoline system
would only need to be 2600/9000 = 29% efficient to reach
parity with LH2. But note that nothing is ever 100% efficient.
There are _always_ conversion losses. It's a matter of how
much.

Per:
http://en.wikipedia.org/wiki/Internal_combustion_engine#Energy_efficiency

Engine efficiency is limited by thermodynamic laws. "Most steel
engines have a thermodynamic limit of 37%." Further, "most engines
retain an average efficiency of about 18%-20%."

Right away we see it's at least potentially possible for gasoline
to still beat out 100% efficient LH2. But let's go on the low
side and assume a gasoline engine is 18% efficient. Then we need
to figure out the efficiency required of an LH2 system to beat
gasoline:

9000 * 18% = 1620
1620 / 2600 = 62%

Therefore an LH2 system would have to be 62% efficient overall to
beat a typical gasoline engine.

Per the same Wikipedia article, "Electric motors are better still,
at around 85%-90% efficiency or more, but they rely on an external
power source (often another heat engine at a power plant subject to
similar thermodynamic efficiency limits)."

OK. So an electric motor _by itself_ is more than efficient, but
as stated it has to get it's electricity from somewhere else. We
are assuming an LH2 powered source.

Let's go with the high side of 90% on the electric motor. So we
have to now figure out what efficiency is required in converting
LH2 to electrity so a 90% efficient electric motor produces
1620 Wh/l of LH2...

1620/.90/2600 = 69%

Now that leaves us with finding out how efficiently LH2 can be
converted to electricity.

Per: http://energy.gov/eere/fuelcells/fuel-cells

"Fuel cells can operate at higher efficiencies than combustion
engines, and can convert the chemical energy in the fuel to
electrical energy with efficiencies of up to 60%."

So we may be coming up a bit short.

However, all my pondering here is surely a gross oversimplification.
And it's possible I goofed on my math or went astray with my logic.
And I imagine different sources will give different numbers. But I
hope it gives you some idea. There are surely other factors that
need to be taken into account. Some may make things work out better,
others may make things worse.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[[email protected]]

Skywise > wrote:
> Larry Dighera > wrote in
> :
> [i]
>> Hello Brian,
>>
>> You seem to have firm grasp of the physics involved. Are you able to
>> suggest how efficient an electric power system powered by LH2 would have
>> to be to offset the power density difference from gasoline/kerosene?
>
> A quick disclaimer.... I don't have any degrees in this stuff or
> work with it. I just happen to be very interested in the sciences
> in general and have taught myself a few things over the years.
> Having said that, I try very hard to check my facts and figures
> before I say anything. I have an allergy to foot-in-mouth disease.
>
> On to your question....
>
> Per numbers in http://www.tinaja.com/glib/energfun.pdf
>
> Liquid H2 has an energy density of 2600 Watt-hours/liter.
> Gasoline is 9000 Watt-hours/liter.
>
>
>
> If we make an assumption for discussion's sake that an LH2
> powered system were 100% efficient, then the gasoline system
> would only need to be 2600/9000 = 29% efficient to reach
> parity with LH2. But note that nothing is ever 100% efficient.
> There are _always_ conversion losses. It's a matter of how
> much.
>
> Per:
> http://en.wikipedia.org/wiki/Internal_combustion_engine#Energy_efficiency
>
> Engine efficiency is limited by thermodynamic laws. "Most steel
> engines have a thermodynamic limit of 37%." Further, "most engines
> retain an average efficiency of about 18%-20%."
>
> Right away we see it's at least potentially possible for gasoline
> to still beat out 100% efficient LH2. But let's go on the low
> side and assume a gasoline engine is 18% efficient. Then we need
> to figure out the efficiency required of an LH2 system to beat
> gasoline:
>
> 9000 * 18% = 1620
> 1620 / 2600 = 62%
>
> Therefore an LH2 system would have to be 62% efficient overall to
> beat a typical gasoline engine.
>
> Per the same Wikipedia article, "Electric motors are better still,
> at around 85%-90% efficiency or more, but they rely on an external
> power source (often another heat engine at a power plant subject to
> similar thermodynamic efficiency limits)."
>
> OK. So an electric motor _by itself_ is more than efficient, but
> as stated it has to get it's electricity from somewhere else. We
> are assuming an LH2 powered source.
>
> Let's go with the high side of 90% on the electric motor. So we
> have to now figure out what efficiency is required in converting
> LH2 to electrity so a 90% efficient electric motor produces
> 1620 Wh/l of LH2...
>
> 1620/.90/2600 = 69%
>
> Now that leaves us with finding out how efficiently LH2 can be
> converted to electricity.
>
> Per: http://energy.gov/eere/fuelcells/fuel-cells
>
> "Fuel cells can operate at higher efficiencies than combustion
> engines, and can convert the chemical energy in the fuel to
> electrical energy with efficiencies of up to 60%."
>
> So we may be coming up a bit short.
>
> However, all my pondering here is surely a gross oversimplification.
> And it's possible I goofed on my math or went astray with my logic.
> And I imagine different sources will give different numbers. But I
> hope it gives you some idea. There are surely other factors that
> need to be taken into account. Some may make things work out better,
> others may make things worse.
>
> Brian

The efficiency numbers look to me to be back of an envelope correct.

The real world, however, has very little interest in the energy efficiency
of things like airplanes.

Some numbers that people care about are endurance, operating cost. initial
cost, and life time maintenance cost.

Given some reference platform, such as a C-172, what would be the enduraance
of a LH2 system for that platform versus gas?

How much does 1 hour of LH2 cost versus gas?

In what column do we put the typical 1%/day evaporation loss of LH2 and
the venting equipment you would have to have in a hanger to get rid of
it?

We can swag what a LH2 system would cost from commercial stuff, but how
much of an adder will aircraft certification cost?

LH2 tanks have limited life; inspection and replacement costs?

Energy efficiency is nice to talk about, but it is dollars that make
things happen.


--
Jim Pennino

[Skywise]

wrote in :

> The efficiency numbers look to me to be back of an envelope correct.

And that's all I guarantee them for! :)

I was about to do some more calculations to try to answer your
questions, and in the process of searching for numbers I found
the following Wikipedia article.

http://en.wikipedia.org/wiki/Hydrogen_economy

At a glance this article seems to cover a lot of the issues
being discussed. I for one would like to read it before trying
to answer. It might be worth other's to read as well.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[[email protected]]

Skywise > wrote:
> wrote in :
>
>> The efficiency numbers look to me to be back of an envelope correct.
>
> And that's all I guarantee them for! :)
>
> I was about to do some more calculations to try to answer your
> questions, and in the process of searching for numbers I found
> the following Wikipedia article.
>
> http://en.wikipedia.org/wiki/Hydrogen_economy
>
> At a glance this article seems to cover a lot of the issues
> being discussed. I for one would like to read it before trying
> to answer. It might be worth other's to read as well.
>
> Brian

After reading that article, I have come to the conclusion that hydrogen
as fuel will become a general economic reality only if at least one of two
things happen:

The world runs out of petroleum, natural gas, and coal and there is no
other choice.

There is huge advancement in electricity production, such as cheap
fusion.

http://en.wikipedia.org/wiki/Hydrogen_economy#Costs


--
Jim Pennino

[Skywise]

wrote in :

> After reading that article, I have come to the conclusion that hydrogen
> as fuel will become a general economic reality only if at least one of two
> things happen:
>
> The world runs out of petroleum, natural gas, and coal and there is no
> other choice.
>
> There is huge advancement in electricity production, such as cheap
> fusion.
>
> http://en.wikipedia.org/wiki/Hydrogen_economy#Costs

I haven't finished the article, but that's also been my general
opinion.

Your item number one has a second ramification. Fossil fuels are
currently the primary mineral source for hydrogen production. So
running out of fossil fuel means switching to hydrogen requires
switching hydrogen production methods. Of course, there's plenty
of sea water, but that leads to your number two.

I think item two is required no matter what we do. Either we use
the electricity directly, or use it to power the production of
things like hydrogen as an energy storage medium. Remember, hydrogen
is not an energy SOURCE, because it has to be manufactured. Fossil
fuel is an energy source because all we have to do is extract it
and do a little refining. It already exists in tangible form.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?

[Larry Dighera]

On Wed, 3 Jun 2015 21:57:44 +0000 (UTC), Skywise >
wrote:

>Larry Dighera > wrote in
:
>[i]
>> Hello Brian,
>>
>> You seem to have firm grasp of the physics involved. Are you able to
>> suggest how efficient an electric power system powered by LH2 would have
>> to be to offset the power density difference from gasoline/kerosene?
>
>A quick disclaimer.... I don't have any degrees in this stuff or
>work with it. I just happen to be very interested in the sciences
>in general and have taught myself a few things over the years.
>Having said that, I try very hard to check my facts and figures
>before I say anything. I have an allergy to foot-in-mouth disease.
>
>On to your question....
>
>Per numbers in http://www.tinaja.com/glib/energfun.pdf
>
>Liquid H2 has an energy density of 2600 Watt-hours/liter.
>Gasoline is 9000 Watt-hours/liter.
>
>
>
>If we make an assumption for discussion's sake that an LH2
>powered system were 100% efficient, then the gasoline system
>would only need to be 2600/9000 = 29% efficient to reach
>parity with LH2. But note that nothing is ever 100% efficient.
>There are _always_ conversion losses. It's a matter of how
>much.
>
>Per:
>http://en.wikipedia.org/wiki/Internal_combustion_engine#Energy_efficiency
>
>Engine efficiency is limited by thermodynamic laws. "Most steel
>engines have a thermodynamic limit of 37%." Further, "most engines
>retain an average efficiency of about 18%-20%."
>
>Right away we see it's at least potentially possible for gasoline
>to still beat out 100% efficient LH2. But let's go on the low
>side and assume a gasoline engine is 18% efficient. Then we need
>to figure out the efficiency required of an LH2 system to beat
>gasoline:
>
>9000 * 18% = 1620
>1620 / 2600 = 62%
>
>Therefore an LH2 system would have to be 62% efficient overall to
>beat a typical gasoline engine.
>
>Per the same Wikipedia article, "Electric motors are better still,
>at around 85%-90% efficiency or more, but they rely on an external
>power source (often another heat engine at a power plant subject to
>similar thermodynamic efficiency limits)."
>
>OK. So an electric motor _by itself_ is more than efficient, but
>as stated it has to get it's electricity from somewhere else. We
>are assuming an LH2 powered source.
>
>Let's go with the high side of 90% on the electric motor. So we
>have to now figure out what efficiency is required in converting
>LH2 to electrity so a 90% efficient electric motor produces
>1620 Wh/l of LH2...
>
>1620/.90/2600 = 69%
>
>Now that leaves us with finding out how efficiently LH2 can be
>converted to electricity.
>
>Per: http://energy.gov/eere/fuelcells/fuel-cells
>
>"Fuel cells can operate at higher efficiencies than combustion
>engines, and can convert the chemical energy in the fuel to
>electrical energy with efficiencies of up to 60%."
>
>So we may be coming up a bit short.
>
>However, all my pondering here is surely a gross oversimplification.
>And it's possible I goofed on my math or went astray with my logic.
>And I imagine different sources will give different numbers. But I
>hope it gives you some idea. There are surely other factors that
>need to be taken into account. Some may make things work out better,
>others may make things worse.
>
>Brian


Hello Brian,

Thank you for your fair and conservative analysis. Very much appreciated.

So generally on a theoretical basis, it is within the realm of possibility that
using LH2 to generate electric power with a fuel-cell to power an electric
motor might be completive in terms of performance with today's General Aviation
internal combustion powered aircraft, because the efficiency of the
electrically powered system is potentially so much greater than the IC
technology, that it compensates for the reduced power density of the LH2 fuel
compared to petroleum. The laws of physics don't prohibit it.

Of course, for this to be realized, significant engineering remains to be
accomplished, but the path to electrically powered aircraft isn't a dead end
due to the laws of physics.

Larry

[Skywise]

Larry Dighera > wrote in
:

> Of course, for this to be realized, significant engineering remains to
> be accomplished, but the path to electrically powered aircraft isn't a
> dead end due to the laws of physics.

VERY SIGNIFICANT engineering.

None of my rough calculations take into consideration the means
by which to store LH2 safely in a vehicle. For one thing, there
will certainly be a weight penalty. If enough, it may offset any
efficiency gains. Steel pressure tanks aren't the lightest things
in the world. I recall work being done in the past in the space
program to make composite LH2 tanks, but they just couldn't ever
withstand the pressures. http://en.wikipedia.org/wiki/Lockheed_Martin_X-33

But here's another safety thought. Would you want planes flying
around that are basically hydrogen 'bombs'? I mean, it's bad
enough when any aircraft crashes, but one with a tank of pressurized
LH2 on board?

hmmm... BLEVE anyone?

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?