Fuel cells producing *liquid* water?

Robert Clark wrote:
...
A material that might be able to reach these criteria is "tetrahedral
amorphous diamond" if used in the form of microspheres.
This report gives an average tensile stength of 7.3 GPa when tested on
micron-scale samples:

Young’s modulus, Poisson’s ratio and failure properties of
tetrahedral amorphous diamond-like carbon for MEMS devices.
J. Micromech. Microeng. 15 (2005) 728–735
doi:10.1088/0960-1317/15/4/009
http://ej.iop.org/links/q03/3NXzoBo,...jmm5_4_009.pdf

The thickness to radius ratio of a spherical pressurized tank is given
by:

h/r = Δp/(2σ)

where h is the wall thickness, r the radius of the sphere, Δp the
overpressure, and σ the tensile strength of the material.

This page gives properties of hydrogen at various pressures and
temperatures (there is deviation from the ideal gas law at very high
pressures):

Hydrogen Properties Package.
http://www.inspi.ufl.edu/data/h_prop_package.html

At a temperature of 300 K, a pressure of 6000 bar gives a density of
72 kg/m^3, or .072 kg/l.
Using a tensile strength of 7.2 GPa = 72,000 bar for the tetrahedral
amorphous diamond and 6000 bar pressure for the hydrogen, the thickness
to radius ratio for a spherical tank would be h/r = 1/24.
The volume for a sphere is V = (4/3)Pi*r^3. For a wall thickness small
compared to the radius, we can take the volume of the wall to be 4*h*
Pi*r^2, which equals (1/6)*Pi*r^3, when h/r = 1/24.
Since the volume of the tank and the wall both have r to the third
power, the radius will cancel when calculating the ratio of the
hydrogen mass to the mass of the tank wall material. So I'll take r =
1. Then the mass of the hydrogen in the tank would be 72*(4/3)*Pi =
301.6 kg.
I'll take the density of tetrahedral amorphous diamond to be that of
diamond, 3500 kg/m^2. Then the mass of the container would be:
3500*(1/6)*Pi = 1885 kg. Then the ratio of the mass of hydrogen to the
container wall mass would be 301.6/1885 = 0.16.
The tetrahedral amorphous diamond is amorphous as is glass. So it may
be that heat and laser irradiation could also allow hydrogen to be
infused and/or released.


Bob Clark

I should have calculated the mass of hydrogen to the total weight. The
total weight is 1885+301.6 = 2186.6 kg. So the weight of the hydrogen
to the total weight is 301.6/2186.6 = .138.


Bob Clark

Eeyore wrote:

Don Lancaster wrote:


dave e wrote:

Don Lancaster wrote:


You have to recognize that converting water vapor to liquid consumes
energy and has to be charged against the fuel cell efficiency budget.

Wow, you got that completely backwards.

Not really.


Yes you did. I spotted it too and if you're trying to weasel your way out of it,
expect to be challenged. Energy is *liberated* when steam condenses.

Graham

So by throwing away energy, the fuel efficiency goes up, you are claiming?



--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email:

Please visit my GURU's LAIR web site at http://www.tinaja.com

Don Lancaster wrote:

Eeyore wrote:

Don Lancaster wrote:

dave e wrote:

Don Lancaster wrote:


You have to recognize that converting water vapor to liquid consumes
energy and has to be charged against the fuel cell efficiency budget.

Wow, you got that completely backwards.

Not really.


Yes you did. I spotted it too and if you're trying to weasel your way out of it,
expect to be challenged. Energy is *liberated* when steam condenses.

Graham

So by throwing away energy, the fuel efficiency goes up, you are claiming?

No, I'm claiming you stated something back-to-front.

Graham

Robert Clark wrote:

Robert Clark wrote:
...
A material that might be able to reach these criteria is "tetrahedral
amorphous diamond" if used in the form of microspheres.
This report gives an average tensile stength of 7.3 GPa when tested on
micron-scale samples:

Young’s modulus, Poisson’s ratio and failure properties of
tetrahedral amorphous diamond-like carbon for MEMS devices.
J. Micromech. Microeng. 15 (2005) 728–735
doi:10.1088/0960-1317/15/4/009
http://ej.iop.org/links/q03/3NXzoBo,...jmm5_4_009.pdf

The thickness to radius ratio of a spherical pressurized tank is given
by:

h/r = Δp/(2σ)

where h is the wall thickness, r the radius of the sphere, Δp the
overpressure, and σ the tensile strength of the material.

This page gives properties of hydrogen at various pressures and
temperatures (there is deviation from the ideal gas law at very high
pressures):

Hydrogen Properties Package.
http://www.inspi.ufl.edu/data/h_prop_package.html

At a temperature of 300 K, a pressure of 6000 bar gives a density of
72 kg/m^3, or .072 kg/l.
Using a tensile strength of 7.2 GPa = 72,000 bar for the tetrahedral
amorphous diamond and 6000 bar pressure for the hydrogen, the thickness
to radius ratio for a spherical tank would be h/r = 1/24.
The volume for a sphere is V = (4/3)Pi*r^3. For a wall thickness small
compared to the radius, we can take the volume of the wall to be 4*h*
Pi*r^2, which equals (1/6)*Pi*r^3, when h/r = 1/24.
Since the volume of the tank and the wall both have r to the third
power, the radius will cancel when calculating the ratio of the
hydrogen mass to the mass of the tank wall material. So I'll take r =
1. Then the mass of the hydrogen in the tank would be 72*(4/3)*Pi =
301.6 kg.
I'll take the density of tetrahedral amorphous diamond to be that of
diamond, 3500 kg/m^2. Then the mass of the container would be:
3500*(1/6)*Pi = 1885 kg. Then the ratio of the mass of hydrogen to the
container wall mass would be 301.6/1885 = 0.16.
The tetrahedral amorphous diamond is amorphous as is glass. So it may
be that heat and laser irradiation could also allow hydrogen to be
infused and/or released.


Bob Clark

I should have calculated the mass of hydrogen to the total weight. The
total weight is 1885+301.6 = 2186.6 kg. So the weight of the hydrogen
to the total weight is 301.6/2186.6 = .138.

Perhaps you could take a cue from the Levitated Dipole Experiment,
for fusion plasma confinement, and find a way
to bond hydrogen to the *outside* of a diamond nanofilament.
Less carbon would be required
if it were on the inside, pulling on the hydrogen,
rather than on the outside pushing.


--- G. R. L. Cowan, former hydrogen fan
Burn boron in pure oxygen for vehicle power:
http://www.eagle.ca/~gcowan/Paper_for_11th_CHC.html

Eeyore wrote:


Don Lancaster wrote:


dave e wrote:

Don Lancaster wrote:


You have to recognize that converting water vapor to liquid consumes
energy and has to be charged against the fuel cell efficiency budget.

Wow, you got that completely backwards.

Not really.


Yes you did.

No, he didn't, in context. The guy is in the Sahara....

Eeyore wrote:

No, I'm claiming you stated something back-to-front.

Another of several hundred claims under your new name. 'Eeyore'????

What a trollllll.....

Dan Bloomquist wrote:

Eeyore wrote:


Don Lancaster wrote:

dave e wrote:

Don Lancaster wrote:


You have to recognize that converting water vapor to liquid consumes
energy and has to be charged against the fuel cell efficiency budget.

Wow, you got that completely backwards.

Not really.


Yes you did.

No, he didn't, in context. The guy is in the Sahara....

Is that so ? I missed that. I thought he was being coy about his operating
location.


Graham

Eeyore wrote:


Dan Bloomquist wrote:


Eeyore wrote:


Don Lancaster wrote:


dave e wrote:


Don Lancaster wrote:



You have to recognize that converting water vapor to liquid consumes
energy and has to be charged against the fuel cell efficiency budget.

Wow, you got that completely backwards.

Not really.


Yes you did.

No, he didn't, in context. The guy is in the Sahara....


Is that so ? I missed that. I thought he was being coy about his operating
location.

No, you are simply posting for the sake of it. A lot of folks on the
sci. groups spend 20 time doing the research. You seem to do 20 time the
posting....

Robert Clark wrote:
...
The Department of Energy has set the ultimate goal for hydrogen energy
storage to be superior to that of gasoline as above 10 MJ energy stored
per kg of total weight and 10 MJ per L of total volume. At an energy
content of hydrogen at 142 MJ per kg, this means about .07 kg of H2 per
kg of total storage system weight and .07 kg of H2 per liter of total
storage system volume.
A material that might be able to reach these criteria is "tetrahedral
amorphous diamond" if used in the form of microspheres.
This report gives an average tensile stength of 7.3 GPa when tested on
micron-scale samples:

Young's modulus, Poisson's ratio and failure properties of
tetrahedral amorphous diamond-like carbon for MEMS devices.
J. Micromech. Microeng. 15 (2005) 728-735
doi:10.1088/0960-1317/15/4/009
http://ej.iop.org/links/q03/3NXzoBo,...jmm5_4_009.pdf

...

That link should be:

Young's modulus, Poisson's ratio and failure properties of
tetrahedral amorphous diamond-like carbon for MEMS devices.
J. Micromech. Microeng. 15 (2005) 728-735
http://ej.iop.org/links/q41/OYlAji77...jmm5_4_009.pdf


Bob Clark

Robert Clark wrote:
Robert Clark wrote:
...
The Department of Energy has set the ultimate goal for hydrogen energy
storage to be superior to that of gasoline as above 10 MJ energy stored
per kg of total weight and 10 MJ per L of total volume. At an energy
content of hydrogen at 142 MJ per kg, this means about .07 kg of H2 per
kg of total storage system weight and .07 kg of H2 per liter of total
storage system volume.
A material that might be able to reach these criteria is "tetrahedral
amorphous diamond" if used in the form of microspheres.
This report gives an average tensile stength of 7.3 GPa when tested on
micron-scale samples:

Young's modulus, Poisson's ratio and failure properties of
tetrahedral amorphous diamond-like carbon for MEMS devices.
J. Micromech. Microeng. 15 (2005) 728-735
doi:10.1088/0960-1317/15/4/009
http://ej.iop.org/links/q03/3NXzoBo,...jmm5_4_009.pdf

...

That link should be:

Young's modulus, Poisson's ratio and failure properties of
tetrahedral amorphous diamond-like carbon for MEMS devices.
J. Micromech. Microeng. 15 (2005) 728-735
http://ej.iop.org/links/q41/OYlAji77...jmm5_4_009.pdf


Bob Clark

Apparently I shouldn't link directly to the pdf file since the link
address changes.
Here's the address for the abstract to the paper:

Young's modulus, Poisson's ratio and failure properties of tetrahedral
amorphous diamond-like carbon for MEMS devices.
Sungwoo Cho et al 2005 J. Micromech. Microeng. 15 728-735
http://www.iop.org/EJ/abstract/0960-1317/15/4/009

There is a link for the full paper on this page. The full paper is
available free for a short period after publication.


Bob Clark