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RGClark
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The energy density usually given for hydrogen is 142 MJ/kg, by which comparison is made to how much hydrogen would have to be carried for it to be competitive with gasoline-fueled vehicles:
Bottling the hydrogen genie.
"One kilogram of hydrogen provides about the same chemical energy (142 MJ) as 1 gal of gasoline (131 MJ). Factoring in the greater efficiency of PEMs [fuel cells], we need to store about 1 kg of hydrogen for every 2 gal of gasoline on a similar internal-combustion-engine vehicle."
http://www.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p20.html
But one of the storage methods is by high pressurization. Quantum Technologies has a hydrogen tank that can store hydrogen at 10,000psi.
But the energy density quoted of 142 MJ/kg does not take into account how much extra energy is added by the high pressure. It seems to me you should get more energy out by using this high pressure.
Let's say you have 8 kg of hydrogen stored at 10,000 psi and 300K temperature. There is deviation from the ideal gas law at this pressure and the density is only about 32kg/m^3. See the hydrogen properties here:
Hydrogen Properties Package.
http://inspi.ufl.edu/data/h_prop_package.html
What kind of power could you get from a turbine using hydrogen at this high pressure?
What other methods could you use to get useful work out of this high pressure?
Bob Clark
Bottling the hydrogen genie.
"One kilogram of hydrogen provides about the same chemical energy (142 MJ) as 1 gal of gasoline (131 MJ). Factoring in the greater efficiency of PEMs [fuel cells], we need to store about 1 kg of hydrogen for every 2 gal of gasoline on a similar internal-combustion-engine vehicle."
http://www.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p20.html
But one of the storage methods is by high pressurization. Quantum Technologies has a hydrogen tank that can store hydrogen at 10,000psi.
But the energy density quoted of 142 MJ/kg does not take into account how much extra energy is added by the high pressure. It seems to me you should get more energy out by using this high pressure.
Let's say you have 8 kg of hydrogen stored at 10,000 psi and 300K temperature. There is deviation from the ideal gas law at this pressure and the density is only about 32kg/m^3. See the hydrogen properties here:
Hydrogen Properties Package.
http://inspi.ufl.edu/data/h_prop_package.html
What kind of power could you get from a turbine using hydrogen at this high pressure?
What other methods could you use to get useful work out of this high pressure?
Bob Clark
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