Hydrogen: Difference between revisions
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*Enthalpy of combustion - 286kJ/mol - [http://en.wikipedia.org/wiki/Hydrogen]. | *Enthalpy of combustion - 286kJ/mol - [http://en.wikipedia.org/wiki/Hydrogen]. | ||
*Heat of combustion (per | *Heat of combustion (per mass) - Compare to gasoline or diesel - enthalpy of combustion of hydrogen is about 3x as large - [http://en.wikipedia.org/wiki/Heat_of_combustion] | ||
*Hydrogen has about 1/8 and 1/3 the volumetric density, resepctively, compared to propane and natural gas. | *Hydrogen has about 1/8 and 1/3 the volumetric density, resepctively, compared to propane and natural gas. | ||
*Let's look at basic calculations. | *Let's look at basic calculations. | ||
*Compare to energy fuel efficiency of gasoline engin - 200 g/kWh, best marine diesel - 150 g/kWhr - [http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption] | *Compare to energy fuel efficiency of gasoline engin - 200 g/kWh, best marine diesel - 150 g/kWhr - [http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption] | ||
Pressurized storage of hydrogen: molar mass of hydrogen molecules is 2 g/mol. 1 mole is about 5 gallons. Pressurized to 100 atm (under 1500 PSI) - readily doable with high pressure electrolyzer - you get 200 grams per 5 gallon container. Max practical for volumetric reasons would be say up to 100 gallons of 20 cu ft volume in cylindrical tanks- say 2 meters by 1 meter wide (base of a single person car). Thus, 100 gallons volume at 100 atm gets you 4 kg of hydrogen. | Pressurized storage of hydrogen: molar mass of hydrogen molecules is 2 g/mol. 1 mole is about 5 gallons. Pressurized to 100 atm (under 1500 PSI) - readily doable with high pressure electrolyzer - you get 200 grams per 5 gallon container. Max practical for volumetric reasons would be say up to 100 gallons of 20 cu ft volume in cylindrical tanks- say 2 meters by 1 meter wide (base of a single person car). Thus, 100 gallons volume at 100 atm gets you 4 kg of hydrogen. For combustion purposes - based on enthalpy of combustion - that is equivalent to about 12 kg of gasoline or diesel. That is about 3 gallons of fuel. | ||
In practical terms - based on our Briggs and Stratton 27 hp gas engine - that is about 75 hp hours. Sufficient for a very small personal vehicle, and arguably more efficient than electric cars from the scalability and Decentralization Perspective. | |||
Revision as of 06:50, 4 February 2015
- Enthalpy of combustion - 286kJ/mol - [1].
- Heat of combustion (per mass) - Compare to gasoline or diesel - enthalpy of combustion of hydrogen is about 3x as large - [2]
- Hydrogen has about 1/8 and 1/3 the volumetric density, resepctively, compared to propane and natural gas.
- Let's look at basic calculations.
- Compare to energy fuel efficiency of gasoline engin - 200 g/kWh, best marine diesel - 150 g/kWhr - [3]
Pressurized storage of hydrogen: molar mass of hydrogen molecules is 2 g/mol. 1 mole is about 5 gallons. Pressurized to 100 atm (under 1500 PSI) - readily doable with high pressure electrolyzer - you get 200 grams per 5 gallon container. Max practical for volumetric reasons would be say up to 100 gallons of 20 cu ft volume in cylindrical tanks- say 2 meters by 1 meter wide (base of a single person car). Thus, 100 gallons volume at 100 atm gets you 4 kg of hydrogen. For combustion purposes - based on enthalpy of combustion - that is equivalent to about 12 kg of gasoline or diesel. That is about 3 gallons of fuel.
In practical terms - based on our Briggs and Stratton 27 hp gas engine - that is about 75 hp hours. Sufficient for a very small personal vehicle, and arguably more efficient than electric cars from the scalability and Decentralization Perspective.