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The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs (2004)

Chapter: Appendix H: Useful Conversions and Thermodynamic Properties

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Suggested Citation:"Appendix H: Useful Conversions and Thermodynamic Properties." National Research Council and National Academy of Engineering. 2004. The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs. Washington, DC: The National Academies Press. doi: 10.17226/10922.
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Appendix H
Useful Conversions and Thermodynamic Properties

TABLE H-1 Conversion Factors

metric ton (tonne) = 1000 kg = 1.1023 short tons

Btu = 1055 J

quad = 1015 Btu = 1.055 EJ

liter = 0.2642 gallons U.S.

cubic meter (m3) = 35.31 cubic feet

conversions for hydrogen:

1 million scf/day = 2.65 short tons/day

1 kg = 11.13 N-m3 (0 degrees Celsius and 1 atmosphere)

1 kg = 415.6 scf (60 degrees Fahrenheit and 1 atmosphere)

NOTE: scf = standard cubic feet; Btu = British thermal unit; EJ = exajoule = 1018 joules; N-m3 = normal cubic meter; kg = kilogram.

TABLE H-2 Thermodynamic Properties of Chemicals of Interest

Parameter

Value

Hydrogen HHV (ΔH)

–286 kJ/mol

Hydrogen LHV (ΔH)

–242 kJ/mol

Methane gross heat of combustion HHV (ΔHc)

–891 kJ/mol

Energy content of 1 kg hydrogen

141.9 MJ (HHV) = 39.4 kWh

120.1 MJ (LHV) = 33.3 kWh

of 1 N-m3 hydrogen

12.7 MJ (HHV)

of 1 pound of hydrogen

64.4 MJ (HHV) = 61.0 kBtu

of 1 gallon gasoline

121.3 MJ (LHV); 115,000 Btu (LHV)

NOTE: HHV = higher heating value; LHV = lower heating value; ΔH = enthalpy; J = joule; Btu = British thermal unit; M = million; k = thousand; mol = mole; N-m3 = normal cubic meter; kWh = kilowatt hour. SOURCE: NIST (2003), except DOE (2003f) for gasoline data.

Suggested Citation:"Appendix H: Useful Conversions and Thermodynamic Properties." National Research Council and National Academy of Engineering. 2004. The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs. Washington, DC: The National Academies Press. doi: 10.17226/10922.
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The announcement of a hydrogen fuel initiative in the President’s 2003 State of the Union speech substantially increased interest in the potential for hydrogen to play a major role in the nation’s long-term energy future. Prior to that event, DOE asked the National Research Council to examine key technical issues about the hydrogen economy to assist in the development of its hydrogen R&D program. Included in the assessment were the current state of technology; future cost estimates; CO2 emissions; distribution, storage, and end use considerations; and the DOE RD&D program. The report provides an assessment of hydrogen as a fuel in the nation’s future energy economy and describes a number of important challenges that must be overcome if it is to make a major energy contribution. Topics covered include the hydrogen end-use technologies, transportation, hydrogen production technologies, and transition issues for hydrogen in vehicles.

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