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.



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The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs 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.