free energy change = 56.32 kcal/mol | for H_{2} + 0.5 O_{2} -> H_{2}O
_{( l )} |

1 km/kWh ~ 22.8 mpge | using the HHV of gasoline |

1 gallon = 3.785 liters | |

1 gpm = 0.0630833 liters/s | |

1 gram = 0.035273961 ounce | |

1 L = 0.035315 cubic foot | |

1 SCF = 1.18 moles | (under ideal gas law). 1 SCF is typically defined at 20 C, 760 mmHg. |

22.5 L = 1 mole | (under ideal gas law at STP - 273.15 K, 1 atm) |

1 atm = 1.013 bar = 101.3 kPa = 760 mmHg = 760 Torr = 14.7 psi | |

0.118 tonnes/barrel ~ 740 kg/m^{3} |
density of vehicle gasoline ("motor spirit") |

332.6 gallons/tonnes ~ 794 kg/m^{3} |
density of methanol |

1 inch of water = 1.86765 mmHg = 0.249 kPa = 0.0361 psi | |

1 calorie = 4.18 J | |

1 BTU = 1055 J | |

1 lb = 0.4536 kg | |

1 hp ~ 746 W | for water, electric, 550 ft.lbf/s horsepower |

1 mile ~ 1.609 km | |

adult: 70 kg; child: 40 kg |

0.444 - 0.646 tonnes of oil equivalent per tonne | energy density of coal |

1.0000 - 1.0415 toe/tonne | energy density of crude oil |

1.130 toe/tonne | energy density of liquefied petroleum gas |

1.070 toe/tonne | energy density of motor gasoline |

33,300 - 42,000 kJ/m^{3} |
energy density of natural as; 40,6000 for Indonesian |

H_{2}: 120 MJ/kg = 33 kWh/kg (LHV) |
hydrogen energy density |

H_{2}: 142 MJ/kg = 39 kWh/kg (HHV) |
hydrogen energy density |

H_{2}: 70.8 kg/m^{3} |
liquid hydrogen density at 20 K |

H_{2}: 10.1 GJ/m^{3} |
liquid hydrogen energy density at 20 K |

Natural gas (as methane): 14 kWh/kg (LHV) | (note correction from previous result) |

Gasoline: 12.3 kWh/kg gasoline (LHV) | (from electric vehicle technology, p. 53) |

Gasoline: 125000 BTU/gallon (HHV) | (Bob) |

Steel flywheel: 12-30 Wh/kg | (electric vehicle technology, p. 53 |

Lead-acid battery: 35-50 Wh/kg | (ibid) |

Advanced battery goal: 200 Wh/kg | (ibid) |

Spiral-wound thin film lead-acid battery: 15 Wh/kg | (1) |

1.0 kW/kg | estimate of Ballard PEM FC stack power density (2) |

0.25 kW/kg | estimate of PEM FC system power density (2) |

1.0 kW/kg | estimate of battery system specific weight (2) |

0.5 kW/kg | estimate of motor and controller weights (3) |

1.5 wt% | metal hydride energy density |

5.0 wt% | compressed gas cylinders; c.f. 7.5% for large, state of the art cylinders |

$20/kg metal hydride | China's GRINM estimate of future costs |

50% H2 HHV to electric power | Average fuel cell conversion efficiency |

$8/GJ of hydrogen | Bob's estimate of H2 prices using ceramic filters |

C_{D}: 0.5 (scooter), 0.33 (car) |
Drag coefficient estimates from [source] |

A_{F}: 2.0 m^{2} (car) |
Frontal area estimate |

C_{RR}: 0.0092 (car) |
Coefficient of tire rolling resistance |

PNGV goal: 3 mph/s accel. at 65 mph | |

PNGV goal: 55 mph on a 6.5 degree slope | |

Car auxiliary load: ~ 400 W | (Tom's paper) |

Scooter auxiliary load: ~ 60 W | (Honda Elite250 manual) |

Car cruising power needed: 6 kW | (on a flat slope) |

Motorcycle economy: 100 mpg | (estimate) |

77% electric to wheels | Estimate of electric drivetrain efficiency |

11,400 miles per year | Average annual passsenger car usage (2) |

(1) Keating, J.; Schroeder, B.; Nelson, R. "Development of a valve-regulated, lead/acid battery for power-assist hybrid electric vehicle use" Bolder Technologies Corporation, Wheat Ridge, CO. 1996

(2) Ogden, Joan M.; Steinbugler, Margaret M.; Kreutz, Thomas G. "A comparison of hydrogen, methanol and gasoline as fuels for fuel cell vehicles: implications for vehicle design and infrastructure development", draft paper

(3) Chang, L. "Recent developments of electric vehicles and their propulsion systems" Proceedings of the 28th Intersociety Engineering Conference, vol. 2, pp. 2.205-2.210, American Chemical Society, 1993

You can email me at bruce@brucelin.ca

Last updated